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Posterior approach interbody fusion techniques such as posterior lumbar interbody fusion and transforaminal interbody fusion are known as the workhorse procedures for lumbar spinal fusion. Over the years, advancements in procedural steps, technique, and technology have sought to improve patient outcomes. Within the last 2 decades, considerable emphasis has been placed upon minimally invasive techniques utilizing tubular retractors and conscious sedation. Innovation in materials engineering, visualization technology such as endoscopes, and enabling technologies such as augmented reality and robotics have served to enhance the procedures and their outcomes., Competing Interests: Disclosure M P. Steinmetz receives royalties/honoraria from Globus, and speaker fees from Cerapedics. Authors A A. Patel, S. Srivatsa, and M A. Davison have no relevant disclosures., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: The comparative effectiveness of decompression plus lumbar facet arthroplasty versus decompression plus instrumented lumbar spinal fusion in patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis is unknown., Methods: In this randomized, controlled, Food and Drug Administration Investigational Device Exemption trial, we assigned patients who had single-level lumbar spinal stenosis and grade-I degenerative spondylolisthesis to undergo decompression plus lumbar facet arthroplasty (arthroplasty group) or decompression plus fusion (fusion group). The primary outcome was a predetermined composite clinical success score. Secondary outcomes included the Oswestry Disability Index (ODI), visual analog scale (VAS) back and leg pain, Zurich Claudication Questionnaire (ZCQ), Short Form (SF)-12, radiographic parameters, surgical variables, and complications., Results: A total of 321 adult patients were randomized in a 2:1 fashion, with 219 patients assigned to undergo facet arthroplasty and 102 patients assigned to undergo fusion. Of these, 113 patients (51.6%) in the arthroplasty group and 47 (46.1%) in the fusion group who had either reached 24 months of postoperative follow-up or were deemed early clinical failures were included in the primary outcome analysis. The arthroplasty group had a higher proportion of patients who achieved composite clinical success than did the fusion group (73.5% versus 25.5%; p < 0.001), equating to a between-group difference of 47.9% (95% confidence interval, 33.0% to 62.8%). The arthroplasty group outperformed the fusion group in most patient-reported outcome measures (including the ODI, VAS back pain, and all ZCQ component scores) at 24 months postoperatively. There were no significant differences between groups in surgical variables or complications, except that the fusion group had a higher rate of developing symptomatic adjacent segment degeneration., Conclusions: Among patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis, lumbar facet arthroplasty was associated with a higher rate of composite clinical success than fusion was at 24 months postoperatively., Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: This study was funded by Premia Spine (the manufacturer of the device being studied), which funded third-party data management and statistical analysis as well as the study coordinators at the study sites. The Article Processing Charge for open access publication was funded by Premia Spine. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H984 )., (Copyright © 2024 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated.)

Objective: The American Spine Registry (ASR) is a collaborative effort between the American Academy of Orthopaedic Surgeons and the American Association of Neurological Surgeons. The goal of this study was to evaluate how representative the ASR is of the national practice with spinal procedures, as recorded in the National Inpatient Sample (NIS)., Methods: The authors queried the NIS and the ASR for cervical and lumbar arthrodesis cases performed during 2017-2019. International Classification of Diseases, 10th Revision and Current Procedural Terminology codes were used to identify patients undergoing cervical and lumbar procedures. The two groups were compared for the overall proportion of cervical and lumbar procedures, age distribution, sex, surgical approach features, race, and hospital volume. Outcomes available in the ASR, such as patient-reported outcomes and reoperations, were not analyzed due to nonavailability in the NIS. The representativeness of the ASR compared to the NIS was assessed via Cohen's d effect sizes, and absolute standardized mean differences (SMDs) of < 0.2 were considered trivial, whereas > 0.5 were considered moderately large., Results: A total of 24,800 arthrodesis procedures were identified in the ASR for the period between January 1, 2017, and December 31, 2019. During the same time period, 1,305,360 cases were recorded in the NIS. Cervical fusions comprised 35.9% of the ASR cohort (8911 cases) and 36.0% of the NIS cohort (469,287 cases). The two databases presented trivial differences in terms of patient age and sex for all years of interest across both cervical and lumbar arthrodeses (SMD < 0.2). Trivial differences were also noted in the distribution of open versus percutaneous procedures of the cervical and lumbar spine (SMD < 0.2). Among lumbar cases, anterior approaches were more common in the ASR than in the NIS (32.1% vs 22.3%, SMD = 0.22), but the discrepancy among cervical cases in the two databases was trivial (SMD = 0.03). Small differences were illustrated in terms of race, with SMDs < 0.5, and a more significant discrepancy was identified in the geographic distribution of participating sites (SMDs of 0.7 and 0.74 for cervical and lumbar cases, respectively). For both of these measures, SMDs in 2019 were smaller than those in 2018 and 2017., Conclusions: The ASR and NIS databases presented a very high similarity in proportions of cervical and lumbar spine surgeries, as well as similar distributions of age and sex, and distribution of open versus endoscopic approach. Slight discrepancies in anterior versus posterior approach among lumbar cases and patient race, and more significant discrepancies in geographic representation were also identified, yet decreasing trends in differences suggested the improving representativeness of the ASR over the course of time and its progressive growth. These conclusions are important to underline the external validity of quality investigations and research conclusions to be drawn from analyses in which the ASR is used.

Study Design: Prospective randomized Food and Drug Administration investigational device exemption clinical trial., Objective: The purpose of the present study is to report the 1-year clinical and radiographic outcomes and safety profile of patients who underwent lumbar facet arthroplasty through implantation of the Total Posterior Spine System (TOPS) device., Summary of Background Data: Lumbar facet arthroplasty is one proposed method of dynamic stabilization to treat grade-1 spondylolisthesis with stenosis; however, there are currently no Food and Drug Administration-approved devices for facet arthroplasty., Methods: Standard demographic information was collected for each patient. Radiographic parameters and patient-reported outcome measures were assessed preoperatively and at regular postoperative intervals. Complication and reoperation data were also collected for each patient., Results: At the time of this study, 153 patients had undergone implantation of the TOPS device. The mean surgical time was 187.8 minutes and the mean estimated blood loss was 205.7cc. The mean length of hospital stay was 3.0 days. Mean Oswestry Disability Index, Visual Analog Score leg and back, and Zurich Claudication Questionnaire scores improved significantly at all postoperative time points ( P >0.001). There were no clinically significant changes in radiographic parameters, and all operative segments remained mobile at 1-year follow-up. Postoperative complications occurred in 11 patients out of the 153 patients (7.2%) who underwent implantation of the TOPS device. Nine patients (5.9%) underwent a total of 13 reoperations, 1 (0.6%) of which was for device-related failure owing to bilateral L5 pedicle screw loosening., Conclusions: Lumbar facet arthroplasty with the TOPS device demonstrated a statistically significant improvement in all patient-reported outcome measures and the ability to maintain motion at the index level while limiting sagittal translation with a low complication rate., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: The purpose of this study was to evaluate the safety and efficacy of a posterior facet replacement device, the Total Posterior Spine (TOPS) System, for the treatment of one-level symptomatic lumbar stenosis with grade I degenerative spondylolisthesis. Posterior lumbar arthroplasty with facet replacement is a motion-preserving alternative to lumbar decompression and fusion. The authors report the preliminary results from the TOPS FDA investigational device exemption (IDE) trial., Methods: The study was a prospective, randomized controlled FDA IDE trial comparing the investigational TOPS device with transforaminal lumbar interbody fusion (TLIF) and pedicle screw fixation. The minimum follow-up duration was 24 months. Validated patient-reported outcome measures included the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain. The primary outcome was a composite measure of clinical success: 1) no reoperations, 2) no device breakage, 3) ODI reduction of ≥ 15 points, and 4) no new or worsening neurological deficit. Patients were considered a clinical success only if they met all four measures. Radiographic assessments were made by an independent core laboratory., Results: A total of 249 patients were evaluated (n = 170 in the TOPS group and n = 79 in the TLIF group). There were no statistically significant differences between implanted levels (L4-5: TOPS, 95% and TLIF, 95%) or blood loss. The overall composite measure for clinical success was statistically significantly higher in the TOPS group (85%) compared with the TLIF group (64%) (p = 0.0138). The percentage of patients reporting a minimum 15-point improvement in ODI showed a statistically significant difference (p = 0.037) favoring TOPS (93%) over TLIF (81%). There was no statistically significant difference between groups in the percentage of patients reporting a minimum 20-point improvement on VAS back pain (TOPS, 87%; TLIF, 64%) and leg pain (TOPS, 90%; TLIF, 88%) scores. The rate of surgical reintervention for facet replacement in the TOPS group (5.9%) was lower than the TLIF group (8.8%). The TOPS cohort demonstrated maintenance of flexion/extension range of motion from preoperatively (3.85°) to 24 months (3.86°)., Conclusions: This study demonstrates that posterior lumbar decompression and dynamic stabilization with the TOPS device is safe and efficacious in the treatment of lumbar stenosis with degenerative spondylolisthesis. Additionally, decompression and dynamic stabilization with the TOPS device maintains segmental motion.

Background: The goal of this study was to identify predictors of prolonged operative time (OT) in patients receiving posterior/transforaminal lumbar interbody fusion (P/TLIF) and examine the relationship between prolonged OT and perioperative outcomes in this population., Methods: The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients undergoing single-level P/TLIF (Common Procedural Terminology code) between 2012 and 2018. Multivariable linear regression models were constructed to identify factors independently associated with changes in OT and examine the relationship between prolonged OT and perioperative outcomes (overall complications, surgical complications, medical complications, 30-day readmission, 30-day reoperation, and length of stay). All models were adjusted for sociodemographic variables, comorbidities, and procedure-specific variables., Results: Our cohort included 6260 patients. After adjusting for baseline covariates, age between 19 and 39 years increased OT by 15.14 minutes, male sex increased OT by 12.91 minutes, African American race increased OT by 17.82 minutes, other race increased OT by 18.13 minutes, obesity class III increased OT by 27.80 minutes, and the use of navigation increased OT by 10.83 minutes. Our multivariate logistic regression also found that after 2 hours, each additional hour of OT was associated with an increased risk of any complication (3-3.99 hours, odds ratio [OR], 1.68; 4-4.99 hours, OR, 2.33; and >5 hours, OR, 4.65). Incremental increases in OT were also associated with an increased risk of extended length of stay, readmission, and return to the operating room., Conclusions: The results of this study highlight several factors associated with prolonged OT and underscore its association with poorer perioperative outcomes. These data can be used to risk stratify patients before single-level P/TLIF., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Osteobiologics are engineered materials that facilitate bone healing and have been increasingly used in spine surgery. Autologous iliac crest bone grafts have been used historically, but morbidity associated with graft harvesting has led surgeons to seek alternative solutions. Allograft bone, biomaterial scaffolds, growth factors, and stem cells have been explored as bone graft substitutes and supplements., Objective: To review current and emerging osteobiologic technologies., Methods: A literature review of English-language studies was performed in PubMed. Search terms included combinations of "spine," "fusion," "osteobiologics," "autologous," "allogen(e)ic," "graft," "scaffold," "bone morphogenic protein," and "stem cells.", Results: Evidence supports allograft bone as an autologous bone supplement or replacement in scenarios where minimal autologous bone is available. There are promising data on ceramics and P-15; however, comparative human trials remain scarce. Growth factors, including recombinant human bone morphogenic proteins (rhBMPs) 2 and 7, have been explored in humans after successful animal trials. Evidence continues to support the use of rhBMP-2 in lumbar fusion in patient populations with poor bone quality or revision surgery, while there is limited evidence for rhBMP-7. Stem cells have been incredibly promising in promoting fusion in animal models, but human trials to this point have only involved products with questionable stem cell content, thereby limiting possible conclusions., Conclusion: Engineered stem cells that overexpress osteoinductive factors are likely the future of spine fusion, but issues with applying viral vector-transduced stem cells in humans have limited progress., (© Congress of Neurological Surgeons 2021.)

Importance: Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction worldwide. It remains unknown whether a ventral or dorsal surgical approach provides the best results., Objective: To determine whether a ventral surgical approach compared with a dorsal surgical approach for treatment of cervical spondylotic myelopathy improves patient-reported physical functioning at 1 year., Design, Setting, and Participants: Randomized clinical trial of patients aged 45 to 80 years with multilevel cervical spondylotic myelopathy enrolled at 15 large North American hospitals from April 1, 2014, to March 30, 2018; final follow-up was April 15, 2020., Interventions: Patients were randomized to undergo ventral surgery (n = 63) or dorsal surgery (n = 100). Ventral surgery involved anterior cervical disk removal and instrumented fusion. Dorsal surgery involved laminectomy with instrumented fusion or open-door laminoplasty. Type of dorsal surgery (fusion or laminoplasty) was at surgeon's discretion., Main Outcomes and Measures: The primary outcome was 1-year change in the Short Form 36 physical component summary (SF-36 PCS) score (range, 0 [worst] to 100 [best]; minimum clinically important difference = 5). Secondary outcomes included 1-year change in modified Japanese Orthopaedic Association scale score, complications, work status, sagittal vertical axis, health resource utilization, and 1- and 2-year changes in the Neck Disability Index and the EuroQol 5 Dimensions score., Results: Among 163 patients who were randomized (mean age, 62 years; 80 [49%] women), 155 (95%) completed the trial at 1 year (80% at 2 years). All patients had surgery, but 5 patients did not receive their allocated surgery (ventral: n = 1; dorsal: n = 4). One-year SF-36 PCS mean improvement was not significantly different between ventral surgery (5.9 points) and dorsal surgery (6.2 points) (estimated mean difference, 0.3; 95% CI, -2.6 to 3.1; P = .86). Of 7 prespecified secondary outcomes, 6 showed no significant difference. Rates of complications in the ventral and dorsal surgery groups, respectively, were 48% vs 24% (difference, 24%; 95% CI, 8.7%-38.5%; P = .002) and included dysphagia (41% vs 0%), new neurological deficit (2% vs 9%), reoperations (6% vs 4%), and readmissions within 30 days (0% vs 7%)., Conclusions and Relevance: Among patients with cervical spondylotic myelopathy undergoing cervical spinal surgery, a ventral surgical approach did not significantly improve patient-reported physical functioning at 1 year compared with outcomes after a dorsal surgical approach., Trial Registration: ClinicalTrials.gov Identifier: NCT02076113.

Study Design: Retrospective population database study., Objective: To investigate the relationship of preoperative hyponatremia to postoperative morbidity and mortality in lumbar interbody fusion patients., Summary of Background Data: Optimization of preoperative patient selection and perioperative management can improve patient outcomes in spinal surgery. Hyponatremia, incidentally identified in 1.7% of the US population, has previously been tied to poorer postoperative outcomes in both the general surgery and orthopedic surgery populations., Materials and Methods: Using the National Surgical Quality Improvement Program database, the authors identified all lumbar interbody fusion patients treated between 2012 and 2014. Patients were classified as hyponatremic (Na<135 mEq/L) or as having normal sodium levels (135-145 mEq/L) preoperatively. The primary outcome was major morbidity and secondary endpoints were prolonged hospitalization, 30-day readmission, and reoperation. Multivariable linear regression was used to find independent predictors of these outcomes., Results: Of 10,654 patients, 45.6% were male individuals, 5.5% were hyponatremic, and 4.2% experienced a major postoperative complication. On multivariable analysis, preoperative hyponatremia was independently associated with major morbidity (odds ratio, 1.22; 95% confidence interval, 1.03-1.44; P<0.05) and prolonged hospitalization (odds ratio, 1.14; 95% confidence interval, 1.02-1.27)., Conclusions: Here the authors provide the first evidence suggesting preoperative hyponatremia is an independent predictor of major morbidity after lumbar interbody fusion. Hyponatremia may represent a modifiable risk factor for improved patient care and preoperative risk counseling., Competing Interests: M.P.S.: consultant for Globus Medical and Intellirod; royalties from Elsevier and Zimmer Biomet; honorarium from Globus Medical and Stryker; research support from Globus Medical. T.E.M.: consultant for Globus Medical. Royalties from Stryker. The remaining authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Preoperative patient optimization is increasingly recognized as key to good surgical outcomes. Preoperative hyponatremia is a modifiable risk factor linked to poorer postoperative outcomes in other surgical fields. We provide the first investigation of the association of preoperative hyponatremia with morbidity and mortality in patients undergoing cervical spine surgery., Methods: We queried the National Surgical Quality Improvement Program registry for patients who underwent cervical spine fusion. Preoperative serum sodium levels were classified as normal (135-145 mEq/L) or hyponatremic (<135 mEq/L); hypernatremic patients were excluded from the analysis. Multivariable logistic analyses using a multiple imputations methodology were performed to determine significant predictors of major morbidity and mortality (MMM)., Results: We included 20,817 patients, of whom 5.2% were hyponatremic at presentation. Preoperative hyponatremia was a significant predictor of MMM (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.09-1.39), mortality (OR, 1.36; 95% CI, 1.03-1.77), major morbidity (OR, 1.24; 95% CI, 1.10-1.40), and odds of prolonged hospitalization (OR, 1.13; 95% CI, 1.04-1.23). Other significant predictors of MMM included age, undergoing an emergent versus nonemergent operation, having chronic obstructive pulmonary disease, having disseminated malignancy, being functionally dependent, presenting with sepsis or septic shock, and having an American Society of Anesthesiologists status of 3, 4, or 5. Similar results were seen in analyses using only complete cases and in sensitivity analyses., Conclusions: Using the National Surgical Quality Improvement Program database, hyponatremia is observed in approximately 1 in every 20 patients undergoing cervical spine fusion. More importantly, it is a predictor of mortality, major morbidity, and prolonged hospitalization. From a systems-level perspective, preoperative hyponatremia may therefore represent a point of intervention for preoperative patient optimization., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Spine surgery has evolved over centuries from first being practiced with Hippocratic boards and ladders to now being able to treat spinal pathologies with minimal tissue invasion. With the advent of new imaging and surgical technologies, spine surgeries can now be performed minimally invasively with smaller incisions, less blood loss, quicker return to daily activities, and increased visualization. Modern minimally invasive procedures include percutaneous pedicle screw fixation techniques and minimally invasive lateral approach for lumbar interbody fusion (i.e., minimally invasive transforaminal lumbar interbody fusion, extreme lateral interbody fusion, oblique lateral interbody fusion) and midline lumbar fusion with cortical bone trajectory screws. Just as evolutions in surgical techniques have helped revolutionize the field of spine surgery, imaging technologies have also contributed significantly. The advent of computer image guidance has allowed spine surgeons to advance their ability to refine surgical techniques, increase the accuracy of spinal hardware placement, and reduce radiation exposure to the operating room staff. As the field of spine surgery looks to the future, many novel technologies are on the horizon, including robotic spine surgery, artificial intelligence, and machine learning to help improve preoperative planning, improve surgical execution, and optimize patient selection to ensure improved postoperative outcomes and patient satisfaction. As more spine surgeons begin incorporating these novel minimally invasive techniques into practice, the field of minimally invasive spine surgery will continue to innovate and evolve over the coming years., (Copyright © 2020. Published by Elsevier Inc.)

Background Context: Anterior lumbar interbody fusion (ALIF) exposes the anterior aspect of the spine through a retroperitoneal approach. Access to the anterior spine requires mobilization of intra-abdominal viscera/vasculature, which can become complicated as scarring and/or adhesions develop from prior abdominal surgical interventions, increasing risk of intraoperative complications. The literature suggests that "significant prior abdominal surgery" is a relative contraindication of ALIF surgery; however, there is no consensus within the literature as to what defines "major/significant" abdominal surgeries. Additionally, the association between the number of prior abdominal surgeries and perioperative complications in ALIF surgery has not been explored within the literature., Purpose: This study seeks to explore the association between perioperative complications of ALIF surgery and the type (major and/or minor) and number of prior abdominal surgeries., Design: A retrospective cohort study was performed to examine perioperative complications in ALIF patients with or without prior history of abdominal surgery., Patient Sample: All consecutive patients undergoing ALIF with or without a history of prior abdominal surgery from 2008 to 2018 at a single tertiary center were evaluated. Patients under the age of 18, patients with spinal malignancy, or patients who had ALIF above L3 were excluded., Outcome Measures: Perioperative complications included intraoperative complications during ALIF surgery and postoperative complications within 90 days of ALIF surgery. Intraoperative complications include vascular injury, ureter injury, retroperitoneal hematoma, etc. Postoperative complications include urinary tract infection, revision of abdominal scar, ileus, deep vein thrombosis, pulmonary embolism, etc. Other outcome measures include readmission within 90 days, length of ALIF surgery, and length of hospital stay., Methods: Electronic medical records of 660 patients who underwent ALIF between 2008 and 2018 were retrospectively reviewed. Patient demographics, Charleston Comorbidity Index (CCI), level of fusion, past abdominal surgical history, use of access surgeon during exposure, intraoperative, and postoperative complications were collected. Predictors of intraoperative and postoperative complications were analyzed using simple and multivariable logistic regression. Statistical analysis was performed using JMP 14.0 (SAS, Cary, NC, USA) software., Results: After controlling for age, length of ALIF, gender, multilevel ALIF, and the use of an access surgeon, there was no significant association between the type of prior abdominal surgery (major and/or minor) and intraoperative complications on multivariable logistic regression analysis (Minor: odds ratio [OR]=1.68; 95% confidence interval [CI]: 0.58-4.86 & Major: OR=1.99; 95% CI: 0.80-4.91). On multivariable logistic regression, the odds of developing an intraoperative complication increases by 52% for each additional prior abdominal surgery after adjusting for age, length of ALIF, gender, multilevel ALIF, and the use of an access surgeon (OR=1.52, 95% CI: 1.10-2.11). Iliac vein laceration was the most common intraoperative complication (n=27, 4%). Neither the type (major and/or minor) nor the number of prior abdominal surgeries were significant predictors of postoperative complications (Minor: OR=1.29; 95% CI: .72-2.31, Major: OR=1.24; 95% CI: 0.77-2.00, & Number: OR=1.03; 95% CI: .84-1.26)., Conclusion: With each additional prior abdominal surgery, accumulation of scarring and adhesions can likely obscure anatomical landmarks and increase the risk of developing an intraoperative complication. Therefore, the number of prior abdominal surgeries should be taken into consideration during planning and operative exposure of the anterior spine via a retroperitoneal approach., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background Context: Bertolotti syndrome (BS) is caused by pseudoarticulation between an aberrant L5 transverse process and the sacral ala, termed a lumbosacral transitional vertebra (LSTV). BS is thought to cause low back pain and is treated with resection or fusion, both of which have shown success. Acquiring cadavers with BS is challenging. Thus, we combined 3D printing, based on BS patient CT scans, with normal cadaveric spines to create a BS model. We then performed biomechanical testing to determine altered kinematics from LSTV with surgical interventions. Force sensing within the pseudojoint modeled nociception for different trajectories of motion and surgical conditions., Purpose: This study examines alterations in spinal biomechanics with LSTVs and with various surgical treatments for BS in order to learn more about pain and degeneration in this condition, in order to help optimize surgical decision-making. In addition, this study evaluates BS histology in order to better understand the pathology and to help define pain generators-if, indeed, they actually exist., Study Design/setting: Model Development: A retrospective patient review of 25 patients was performed to determine the imaging criteria that defines the classical BS patient. Surgical tissue was extracted from four BS patients for 3D-printing material selection. Biomechanical Analysis. This was a prospective cadaveric biomechanical study of seven spines evaluating spinal motions, and loads, over various surgical conditions (intact, LSTV, and LSTV with various fusions). Additionally, forces at the LSTV joint were measured for the LSTV and LSTV with fusion condition. Histological Analysis: Histologic analysis was performed prospectively on the four surgical specimens from patients undergoing pseudoarthrectomy for BS at our institution to learn more about potential pain generators., Patient Sample: The cadaveric portion of the study involved seven cadaveric spines. Four patients were prospectively recruited to have their surgical specimens assessed histologically and biomechanically for this study. Patients under the age of 18 were excluded., Outcome Measures: Physiological measures recorded in this study were broken down into histologic analysis, tissue biomechanical analysis, and joint biomechanical analysis. Histologic analysis included pathologist interpretation of Hematoxylin and Eosin staining, as well as S-100 staining. Tissue biomechanical analysis included stiffness measurements. Joint biomechanical analysis included range of motion, resultant torques, relative axis angles, and LSTV joint forces., Methods: This study received funding from the American Academy of Neurology Medical Student Research Scholarship. Three authors hold intellectual property rights in the simVITRO robotic testing system. No other authors had relevant conflicts of interest for this study. CT images were segmented for a representative BS patient and cadaver spines. Customized cutting and drilling guides for LSTV attachment were created for individual cadavers. 3D-printed bone and cartilage structural properties were based on surgical specimen stiffness, and specimens underwent histologic analysis via Hematoxylin and Eosin, as well as S-100 staining. Joint biomechanical testing was performed on the robotic testing system for seven specimens. Force sensors detected forces in the LSTV joint. Kruskal-Wallis tests and Dunnett's tests were used for statistical analysis with significance bounded to p<.05., Results: LSTV significantly reduces motion at the L5-S1 level, particularly in lateral bending and axial rotation. Meanwhile, the LSTV increases adjacent segment motion significantly at the L2-L3 level, whereas other levels have nonsignificant trends toward increased motion with LSTV alone. Fusion involving L4-S1 (L4-L5 and L5-S1) to treat adjacent level degeneration associated with an LSTV is associated with a significant increase in adjacent segment motion at all levels other than L5-S1 compared to LSTV alone. Fusion of L5-S1 alone with LSTV significantly increases L3-L4 adjacent segment motion compared to LSTV alone. Last, ipsilateral lateral bending with or without ipsilateral axial rotation produces the greatest force on the LSTV, and these forces are significantly reduced with L5-S1 fusion., Conclusions: BS significantly decreases L5-S1 mobility, and increases some adjacent segment motion, potentially causing patient activity restriction and discomfort. Ipsilateral lateral bending with or without ipsilateral axial rotation may cause the greatest discomfort overall in these patients, and fusion of the L5-S1 or L4-S1 levels may reduce pain associated with these motions. However, due to increased adjacent segment motion with fusions compared to LSTV alone, resection of the joint may be the better treatment option if the superior levels are not unstable preoperatively., Clinical Significance: This study's results indicate that patients with BS have significantly altered spinal biomechanics and may develop pain due to increased loading forces at the LSTV joint with ipsilateral lateral bending and axial rotation. In addition, increased motion at superior levels when an LSTV is present may lead to degeneration over time. Based upon results of LSTV joint force testing, these patients' pain may be effectively treated surgically with LSTV resection or fusion involving the LSTV level if conservative management fails. Further studies are being pursued to evaluate the relationship between in vivo motion of BS patients, spinal and LSTV positioning, and pain generation to gain a better understanding of the exact source of pain in these patients. The methodologies utilized in this study can be extrapolated to recreate other spinal conditions that are poorly understood, and for which few native cadaveric specimens exist., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Carotid artery injury and stroke secondary to prolonged retraction remains an extremely rare complication in anterior cervical discectomy and fusion (ACDF). However, multiple studies have demonstrated that carotid artery retraction during the surgical approach may alter the normal blood flow, leading to a significant reduction in the cross-sectional area of the vessel. Others have suggested that dislodgment of atherosclerotic plaques following manipulation of the carotid artery can be a potential risk for intracranial embolus and stroke., Purpose: We aimed to evaluate: (1) the incidence of postoperative stroke following ACDF and (2) incidence of other postoperative complications in a cohort of patients who had a diagnosis of carotid artery stenosis (CAS) versus those who did not., Patient Sample: This study utilized the Statewide Planning and Research Cooperative System database from January 1, 2009 to December 31, 2013. All patients who underwent (ACDF) and had a preoperative diagnosis of CAS were identified using the International Classification of Disease, ninth revision codes. Those who had a previous history of stroke were excluded. Patients who had CAS were propensity score matched to patients without history of CAS for demographics and Charlson/Deyo comorbidity scores., Outcome Measures: Incidence of postoperative stroke and other complications were compared between the cohorts. The threshold for statistical significance was set at a p<.05. This study received no funding. The authors report no conflict of interests relevant to this study., Results: There were 34,975 patients who underwent an ACDF in the study time period. After excluding those under the age of 18 and with history of previous stroke, there were 61 patients who had CAS that were compared with a propensity-matched cohort. The CAS cohort had a significantly higher incidence of postoperative stroke during their hospitalization (6.6% vs 0%, p<.042). The CAS cohort also had higher rates of acute renal failure (27.9% vs 4.9%, p = .01) and sepsis (18% vs 4.9%, p = .023). There were no stroke related deaths., Conclusions: Patients with CAS who underwent ACDF had a statistically significant greater incidence of developing a postoperative stroke. To the best of our knowledge, no previous study has evaluated the development of postoperative stroke in patients with CAS undergoing ACDF. Larger, multicenter studies are needed to estimate the true incidence of stroke in this specific patient population. However, our results may illustrate the importance of preoperative optimization, approach-selection, and postoperative stroke surveillance in patients with a history of CAS who undergoes ACDF., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background Context: Degenerative changes in the cervical spine occur in an age-dependent manner. As the US population continues to age, the incidence of age-dependent, multilevel, degenerative cervical pathologies is expected to increase. Similarly, the average age of patients with cervical spondylotic myelopathy (CSM) will likely trend upward. Posterior cervical fusion (PCF) is often the treatment modality of choice in the management of multilevel cervical spine disease. Although outcomes following anterior cervical fusion for degenerative disease have been studied among older patients (aged 80 years and older), it is unknown if these results extend to octogenarian patients undergoing PCF for the surgical management of CSM., Purpose: The present study aimed to quantify surgical outcomes following PCF for the treatment of CSM among the octogenarian patient population compared with patients younger than 80 years old., Study Design/setting: This was a retrospective study that used the National Surgical Quality Improvement Program (NSQIP)., Patient Sample: The sample included patients aged 60-89 who had CSM and who underwent PCF from 2012 to 2014., Outcome Measures: The outcome measures were multimorbidity, prolonged length of stay (LOS), discharge disposition (to home or skilled nursing/rehabilitation facility), 30-day all-cause readmission, and 30-day reoperation., Methods: The NSQIP database was queried for patients with CSM (International Classification of Disease, Ninth Revision, Clinical Modification code 721.1) aged 60-89 who underwent PCF (Current Procedural Terminology code 22600) from 2012 to 2014. Cohorts were defined by age group (60-69, 70-79, 80-89). Data were collected on gender, race, elective or emergent status, inpatientor outpatient status, where patients were admitted from (home vs. skilled nursing facility), American Society of Anesthesiologists class, comorbidities, and single- or multilevel fusion. After controllingfor these variables, logistic regression analysis was used to compare outcome measures in the different age groups., Results: A total of 819 patients with CSM who underwent PCF (416 aged 60-69, 320 aged 70-79, and 83 aged 80-89) were identified from 2012 to 2014. Of the PCF procedures, 79.7% were multilevel. There were no significant differences in the odds of multimorbidity, prolonged LOS, readmission, or reoperation when comparing octogenarian patients with CSM with patients aged 60-69 or 70-79. Patients aged 60-69 and 70-79 were significantly more likely to be discharged to home than patients over 80 (odds ratio [OR] 4.3, 95% confidence interval [CI] 1.8-10.4, p<.0001, and OR 2.7, 95% CI 1.1-6.4, p=.0005, respectively)., Conclusions: Compared with patients aged 60-69 and 70-79, octogenarian patients with CSM were significantly more likely to be discharged to a location other than home following PCF. After controlling for patient comorbidities and demographics, 80- to 89-year-old patients with CSM who underwent PCF did not differ in other outcomes when compared with the other age cohorts. These results can improve preoperative risk counseling and surgical decision-making., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background Context: The United States Centers for Disease Control and Prevention estimates the prevalence of inflammatory bowel disease (IBD) at more than 3.1 million people. As diagnostic techniques and treatment options for IBD improve, the prevalence of IBD is expected to increase. For spine surgeons, patients with IBD have a unique complication profile because patients with IBD may present with poor nutritional status and because the medications used to manage IBD have been associated with poor vertebral bone mineralization and immunosuppression. Presently, there are very limited data regarding perioperative outcomes among patients with IBD who undergo spinal surgery. The present study begins to address this knowledge gap by describing trends in patients with IBD undergoing lumbar fusion and by quantifying the association between IBD and immediate postoperative outcomes using a large, national database., Purpose: To advance our understanding of the potential pitfalls and risks associated with lumbar fusion surgery in patients with IBD., Design/setting: Retrospective cross-sectional analysis., Patient Sample: The Nationwide Inpatient Sample (NIS) database was queried from 1998 to 2011 to identify adult patients (18+) who underwent primary lumbar fusion operations using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) coding., Outcome Measures: Incidence of lumbar fusion procedures, prevalence of IBD, complication rates, length of stay, and total hospital charges., Methods: The annual number of primary lumbar fusion operations performed between 1998 and 2011 was obtained from the NIS database. Patients younger than 18 years of age were excluded. The prevalence of IBD in this population (both Crohn disease and ulcerative colitis) was determined using ICD-9-CM codes. Logistic regression models were estimated to determine the association between IBD and the odds of postoperative medical and surgical complications, while controlling for patient demographics, comorbidity burden, and hospital characteristics. The complex survey design of the NIS was taken into account by clustering on hospitals and assuming an exchangeable working correlation using the discharge weights supplied by the NIS. We accounted for multiple comparisons using the Bonferroni correction and an alpha level for statistical significance of . 0028., Results: The prevalence of IBD is increasing among patients undergoing lumbar fusion, from 0.21% of all patients undergoing lumbar fusion in 1998 to 0.48% of all patients undergoing lumbar fusion in 2011 (p<.001). The odds of experiencing a postoperative medical or surgical complication were not significantly different when comparing patients with IBD with control patients without IBD after controlling for patient demographics, comorbidity burden, and hospital characteristics (adjusted odds ratio=1.1, 95% confidence interval [CI] 0.99-1.3, p=.08). On multivariable analysis, the presence of IBD in patients undergoing lumbar fusion surgery was associated with longer length of stay and greater hospitalization charges., Conclusions: Among patients who underwent lumbar fusion, IBD is a rare comorbidity that is becoming increasingly more common. Importantly, patients with IBD were not at increased risk of postoperative complications. Spine surgeons should be prepared to treat more patients with IBD and should incorporate the present findings into preoperative risk counseling and patient selection., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background Context: Lumbar fusion is an effective and durable treatment for symptomatic lumbar spondylolisthesis; however, the current literature provides insufficient evidence to recommend an optimal surgical fusion strategy., Purpose: The present study aims to compare the clinical outcomes, fusion rates, blood loss, and operative times between open posterolateral lumbar fusion (PLF) alone and open transforaminal lumbar interbody fusion (TLIF) + posterolateral fusion for spondylolisthesis., Study Design: This is a systematic literature review and meta-analysis of English language studies for the treatment of spondylolisthesis with PLF versus PLF + TLIF., Patient Sample: Data were obtained from published randomized controlled trials (RCTs) and retrospective cohort studies., Outcome Measures: Clinical outcomes included Oswestry Disability Index (ODI), back pain, leg pain, and health-related quality of life (HRQOL) scores. Fusion rate, operative time, blood loss, and infection rate were also assessed., Methods: A literature search of three electronic databases was performed to identify investigations performed comparing PLF alone with PLF + TLIF for treatment of low-grade lumbar spondylolisthesis. The summary effect size was assessed from pooling observational studies for each of the outcome variables, with odds ratios (ORs) used for fusion and infection rate, mean difference used for improvement in ODI and leg pain as well as operative time and blood loss, and standardized mean difference used for improvement in back pain and HRQOL outcomes. Studies were weighed based on the inverse of the variance and heterogeneity. Heterogeneity was assessed using the I 2 -an estimate of the error caused by between-study variation. Effect sizes from the meta-analysis were then compared with data from the RCTs to assess congruence in outcomes., Results: The initial literature search yielded 282 unique, English language studies. Seven were determined to meet our inclusion criteria and were included in our qualitative analysis. Five observational studies were included in our quantitative meta-analysis. The pooled fusion success rates were 84.7% (100/118) in the PLF group and 94.3% (116/123) in the TLIF group. Compared with TLIF patients, PLF patients had significantly lower odds of achieving solid arthrodesis (OR 0.33, 95% confidence interval [CI] 0.13-0.82, p=.02; I 2 =0%). With regard to improvement in back pain, the point estimate for the effect size was -0.27 (95% CI -0.43 to -0.10, p=.002; I 2 =0%), in favor of the TLIF group. For ODI, the pooled estimate for the effect size was -3.73 (95% CI -7.09 to -0.38, p=.03; I 2 =35%), significantly in favor of the TLIF group. Operative times were significantly shorter in the PLF group, with a summary effect size of -25.55 (95% CI -43.64 to -7.45, p<.01; I 2 =54%). No significant difference was observed in leg pain, HRQOL improvement, blood loss, or infection rate. Our meta-analysis results were consistent with RCTs, in favor of TLIF for achieving radiographic fusion and greater improvement in ODI and back pain., Conclusions: Our results demonstrate that for patients undergoing fusion for spondylolisthesis, TLIF is superior to PLF with regard to achieving radiographic fusion. However, current data only provide weak support, if any, favoring TLIF over PLF for clinical improvement in disability and back pain., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background Context: Transforaminal lumbar interbody fusion (TLIF) or anterior lumbar interbody fusion with percutaneous pedicle screws (ALIFPS) offer significantly higher radiographic fusion rates than other fusion techniques for L5-S1 isthmic spondylolisthesis (IS). As it stands, there is a relative paucity of comparative data of the two techniques., Purpose: To define the clinical, radiographic, and financial differences between TLIF and ALIFPS for L5-S1 IS., Design/setting: A retrospective cohort study conducted at a single tertiary care center., Patient Sample: Sixty-six patients who underwent either TLIF or ALIPFS for L5-S1 IS at a single tertiary care center between 2009 and 2014., Outcome Measures: Quality of life outcome scores including the EuroQol-5 Dimensions (EQ-5D), Pain Disability Questionnaire (PDQ), and Patient Health Questionnaire-9 (PHQ-9). Sagittal balance parameters including: pelvic incidence, pelvic tilt, sacral slope, segmental lordosis, total lordosis, degree of slip, disc height, and L1-axis S1 distance (LASD). Cost measures included in-hospital charges, hospital length of stay (LOS), and post-admission costs accrued over 1 year., Methods: Quality of life (QoL) outcome scores, radiographic data, and financial data were collected with a minimum of 1-year follow-up. Clinical results were investigated using the PDQ, PHQ-9, and EQ-5D. Radiographic measurements included lumbar lordosis, segmental lordosis, pelvic tilt, pelvic incidence, height of disc, L-1 axis S-1 distance, and the degree of slip. Cost data were generated based on patient-level resource utilization. Comparative data were presented as median with interquartile range (IQR). Continuous variables were compared using either independent Student t tests assuming unequal variance or Mann-Whitney U tests for parametric and nonparametric variables, respectively. The minimally clinical important difference (MCID) used for each questionnaire was as follows: PDQ (26), PHQ-9 (5), and EQ-5D (0.4)., Results: A total of 66 patients met inclusion criteria. In the ALIFPS cohort, PDQ scores improved from 69 [47, 82] to 26 [18.2, 79.7], p=.02. In the TLIF cohort, PDQ scores improved from 73 [46, 85] to 48.5 [23, 67.5], p=.01. Both groups also showed a significant improvement in EQ-5D scores at 1 year, but the ALIFPS group showed a significantly greater improvement in EQ-5D scores at 1 year (0.1 [0,0.2] vs. 0.2 [0.1, 0.4], p=.02). Furthermore, only the ALIFPS cohort showed a significant improvement in segmental lordosis. The ALIFPS cohort showed a significantly greater improvement in disc height than did TLIF (3.5 [2, 5.5] vs. 6.7 [4.1, 10], p=.01). No significant differences were found in the direct costs of both procedures., Conclusions: Our findings suggest that anterior lumbar interbody fusion with percutaneous pedicle screws can achieve better clinical outcomes compared with TLIF for the treatment of IS. We believe the superior radiographic outcomes achieved through ALIFPS, namely a greater restoration of segmental lordosis and disc height, may have contributed to the improved clinical outcomes presented in the current study., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design: A retrospective cohort study at a single tertiary care center., Objective: To determine the impact of superior segment facet joint violation (FJV) during lumbar fusion on reoperation rates and quality of life (QOL)., Summary of Background Data: Although lumbar fusion is an efficacious and durable treatment for numerous spinal pathologies, adjacent segment degeneration remains a serious complication. FJV has been suggested to alter load-bearing capability and potentially contribute to adjacent segment degeneration., Materials and Methods: Patients who underwent instrumented lumbar fusion surgery between 2009 and 2013 with postoperative computed tomography imaging were included. Patients were placed in the FJV group if either of the superior segment facet joints were compromised by the pedicle screw or rod. Patients with preserved facet joints were placed in the control group. Demographic, perioperative, QOL, and reoperation data were collected. QOL scores including the Pain Disability Questionnaire, Patient Health Questionnaire-9, and EuroQOL 5 Dimensions (EQ-5D) were acquired., Results: Of 240 patients included, 112 patients were found to have FJV and the remaining 128 patients were placed in the control group. One year following lumbar fusion, QOL outcomes and reoperation rates were similar between the FJV and control groups. At 2-year follow-up, patients in the FJV group were less likely to make a significant improvement in EQ-5D (P=0.041). Also, the reoperation rate in the FJV group was significantly higher than in the control group at 2 years (15.2% vs. 6.3%, respectively; P=0.024) and 3 years (19.6% vs. 9.4%, P=0.023). Multivariable logistic regression showed FJV to be an independent predictor of both (1) failing to make a significant improvement in EQ-5D (P=0.046) and (2) undergoing reoperation at both 2 and 3 years postoperatively (P=0.024 and 0.020, respectively)., Conclusions: FJV was independently associated with a higher reoperation rate and diminished improvement in QOL.

Study Design: A retrospective cohort study at a single institution., Objective: To determine the effect of preoperative depression on Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey scores in a lumbar fusion population., Summary of Background Data: HCAHPS surveys are used to assess the quality of the patient experience, and directly influences reimbursement for hospital systems and spine surgeons nationwide. Untreated depression has been linked to worse functional outcomes in spine surgery. We, however, aimed to elucidate whether HCAHPS survey responses were different in depressed patients., Methods: Prospectively collected functional outcome data including Patient Health Questionnaire 9, EuroQol five dimensions, and Pain Disability Questionnaire were analyzed preoperatively. Preoperative Patient Health Questionnaire 9 scores of greater than or equal to 10 (moderate to severe depression) defined our depressed cohort of patients. HCAHPS responses were obtained for each individual, allowing for real-world analysis of outcomes in this population., Results: In our 237 patient cohort, depressed patients were younger, female; were on full disability; and had lower scores on EuroQol five dimensions and Pain Disability Questionnaire preoperatively. Approximately 73.2% of depressed patients felt doctors treated them with respect, compared to 88.8% of patients without depression (P = 0.005). Also, depressed patients felt nurses treated them with less respect (P = 0.014) and that physicians did not listen to them as carefully (P = 0.029). Multivariate regression analysis revealed that patients with preoperative depression had higher odds of patients feeling less respected by both physicians and nurses. Multivariate analysis also revealed that depression was an independent predictor of lower patient satisfaction with nursing response to their needs., Conclusion: In patients undergoing lumbar fusion, preoperative depression was shown to have negative effect on patient experience measured by the HCAHPS survey. These results suggest that depression may be a modifiable risk factor for poor hospital experience., Level of Evidence: 3.

Background Context: Multiple studies have determined minimum clinically important difference (MCID) thresholds for EuroQOL-5 Dimensions (EQ-5D) scores in lumbar fusion patients. However, a comprehensive understanding of predictors for a clinically significant improvement (CSI) postoperatively does not exist., Purpose: To determine medical, radiographic, and surgical predictors for obtaining a CSI following lumbar fusion surgery., Study Design: This is a retrospective review of patients who underwent instrumented lumbar fusion., Patient Sample: We included patients who underwent lumbar fusion for any indication between 2008 and 2013., Outcome Measures: Outcome measures included preoperative and postoperative EQ-5D Index scores., Materials and Methods: The medical records of patients who received a lumbar fusion for any indication were retrospectively reviewed to identify patient medical and surgical characteristics. A blinded reviewer assessed radiographs for each patient to examine sagittal alignment following fusion. Multivariable logistic regression was used to model the achievement of a CSI based on two commonly cited MCID values., Results: A total of 231 patients fit the inclusion criteria; 58% exceeded an MCID value for an EQ-5D score of 0.100, and 16% exceeded an MCID value of 0.390. Statistically significant independent predictors of not obtaining a CSI for an MCID threshold of 0.100 included a higher preoperative EQ-5D score (odds ratio [OR]=44.8) and L5-S1 fusion (OR=3.3). For an MCID value of 0.390, a higher preoperative EQ-5D score (OR=2,080.8) and a diagnosis of depression (OR=7.1) were predictive of not achieving a CSI, whereas spondylolisthesis (OR=4.1) was predictive of obtaining a CSI postoperatively. For both MCID values, patients who achieved a CSI had better postoperative quality of life (QOL) scores for all metrics measured, despite worse QOL scores preoperatively., Conclusions: This study is the first to use a combination of medical, surgical, and postoperative sagittal balance variables as determinants for the achievement of a CSI after lumbar fusion. The awareness of these predictors may allow for better patient selection and surgical approach to decrease the probability of acquiring a poor outcome postoperatively., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Study Design: A retrospective cohort study., Objective: The objective of this study is to compare the radiographic and clinical outcomes of transforaminal lumbar interbody fusion (TLIF) with bilateral facetectomy (BF) versus unilateral facetectomy (UF)., Summary of Background Data: BF is a surgical technique utilized with the intent of creating a greater degree of segmental lordosis than UF alone. However, the clinical benefits of this technique have not been defined. We seek to determine whether a difference exists between bilateral versus UF during TLIF by utilizing both clinical and radiographic outcome measures., Methods: The electronic medical records of 57 patients who underwent single-level TLIF with either a UF (n = 28) or BF (n = 29) were reviewed. Clinical outcomes were measured through Patient Health Questionnaire-9 (PHQ-9), Pain Disability Questionnaire (PDQ), EuroQol 5 Dimensions (EQ-5D) Health State, and Quality Adjusted Life Year (QALY). Radiographic parameters including disc height and sagittal balance were measured on plain radiographs at 1 year following operation., Results: All radiographic parameters showed no significant differences between the UF and BF cohorts. Segmental lordosis increased significantly in both cohorts. However, there was no significant difference in the increase of segmental lordosis between cohorts. Overall lumbar lordosis did not increase significantly in either cohort. Perioperative complications were also similar between cohorts. PDQ and EQ-5D scores improved significantly in both cohorts at 1 year postoperatively. The BF cohort showed a significantly greater improvement in both EQ-5D (0.1 ± 0.2 vs. 0.3 ± 0.2, P = 0.01) and PHQ-9 scores (-0.8 ± 4.6 vs. 4.6 ± 5.2, P = 0.03) than the UF cohort. The PDQ score improved over the minimally clinical important difference (MCID) of 26 in only the BF cohort., Conclusion: The findings in the present study demonstrate that BF during single-level TLIF improves clinical outcomes to a greater degree than UF without any notable differences in perioperative complications or radiographic measurements., Level of Evidence: 3.

Study Design: Retrospective Review., Objective: The aim of this study was to determine medical, radiographic, and surgical risk factors for the development of adjacent segment disease (ASD) after lumbar fusion., Summary of Background Data: ASD is a recognized outcome of spinal fusion that leads to increased costs and debilitating symptoms for patients. However, a comprehensive understanding of risk factors for the development of this surgical outcome does not exist., Methods: The medical records of patients who received their first lumbar fusion for any indication were retrospectively examined for preoperative medical comorbidities and medications, as well as surgical approach and perioperative complications. A blinded reviewer assessed radiographs for each patient to examine sagittal alignment after fusion. Multivariable logistic regression was used to model the risk of developing ASD on the basis of one or more predictors., Results: A total of 137 patients fit the inclusion criteria; 9% required a follow-up operation for degeneration at segments adjacent to the fusion. The ASD group had a mean follow-up of 21.1 months prior to revision surgery and an overall follow-up of 41.0 months. The average follow-up in the control group was 14.0 months. Statistically significant independent predictors of developing ASD included antidepressant use [odds ratio (OR) = 5.4], diagnosis of degenerative scoliosis (OR = 34.2), fusion of L4-S1 (OR = 56.5), having no decompressions adjacent to the fusion, and low sacral slope (OR = 0.9). No patient who developed ASD received a decompression adjacent to the fusion such that an OR could not be generated for this independent predictor., Conclusion: This study is the first to use a combination of medical, surgical, and postoperative sagittal balance as risk factors for the development of adjacent segment disease after lumbar fusion. The awareness of these risk factors may allow for better patient selection and surgical technique to decrease the probability of acquiring this adverse outcome., Level of Evidence: 4.

OBJECTIVE Ossification of the posterior longitudinal ligament (OPLL) is a pathological calcification or ossification of the PLL, predominantly occurring in the cervical spine. Although surgery is often necessary for patients with symptomatic neurological deterioration, there remains controversy with regard to the optimal surgical treatment. In this systematic review and meta-analysis, the authors identified differences in complications and outcomes after anterior or posterior decompression and fusion versus after decompression alone for the treatment of cervical myelopathy due to OPLL. METHODS A MEDLINE, SCOPUS, and Web of Science search was performed for studies reporting complications and outcomes after decompression and fusion or after decompression alone for patients with OPLL. A meta-analysis was performed to calculate effect summary mean values, 95% CIs, Q statistics, and I(2) values. Forest plots were constructed for each analysis group. RESULTS Of the 2630 retrieved articles, 32 met the inclusion criteria. There was no statistically significant difference in the incidence of excellent and good outcomes and of fair and poor outcomes between the decompression and fusion and the decompression-only cohorts. However, the decompression and fusion cohort had a statistically significantly higher recovery rate (63.2% vs 53.9%; p < 0.0001), a higher final Japanese Orthopaedic Association score (14.0 vs 13.5; p < 0.0001), and a lower incidence of OPLL progression (< 1% vs 6.3%; p < 0.0001) compared with the decompression-only cohort. There was no statistically significant difference in the incidence of complications between the 2 cohorts. CONCLUSIONS This study represents the only comprehensive review of outcomes and complications after decompression and fusion or after decompression alone for OPLL across a heterogeneous group of surgeons and patients. Based on these results, decompression and fusion is a superior surgical technique compared with posterior decompression alone in patients with OPLL. These results indicate that surgical decompression and fusion lead to a faster recovery, improved postoperative neurological functioning, and a lower incidence of OPLL progression compared with posterior decompression only. Furthermore, decompression and fusion did not lead to a greater incidence of complications compared with posterior decompression only.

Background Context: Cervical arthroplasty is an increasingly popular alternative for the treatment of cervical radiculopathy and myelopathy. This technique preserves motion at the index and adjacent disc levels, avoiding the restraints of fusion and potentially minimizing adjacent segment pathology onset during the postoperative period., Purpose: This study aimed to identify all prospective studies reporting adjacent segment pathology rates for cervical arthroplasty., Study Design/setting: Systematic review and meta-analysis were carried out., Patient Sample: Studies reporting adjacent segment degeneration (ASDegeneration) and adjacent segment disease (ASDisease) rates in patients who underwent cervical arthroplasty comprised the patient sample., Outcome Measures: Outcomes of interest included reported ASDegeneration and ASDisease events after cervical arthroplasty., Methods: We conducted a MEDLINE, SCOPUS, and Web of Science search for studies reporting ASDegeneration or ASDisease following cervical arthroplasty. A meta-analysis was performed to calculate effect summary values, 95% confidence intervals (CIs), Q values, and I(2) values. Forest plots were constructed for each analysis group., Results: Of the 1,891 retrieved articles, 32 met inclusion criteria. The patient incidence of ASDegeneration and ASDisease was 8.3% (95% CI 3.8%-12.7%) and 0.9% (95% CI 0.1%-1.7%), respectively. The rate of ASDegeneration and ASDisease at individual levels was 10.5% (95% CI 6.1%-14.9%) and 0.2% (95% CI -0.1% to 0.5%), respectively. Studies following patients for 12-24 months reported a 5.1% (95% CI 2.1%-8.1%) incidence of ASDegeneration and 0.2% (95% CI 0.1%-0.2%) incidence of ASDisease. Conversely, studies following patients for greater than 24 months reported a 16.6% (5.8%-27.4%) incidence of ASDegeneration and 2.6% (95% CI 1.0%-4.2%) of ASDisease. This identified a statistically significant increase in ASDisease diagnosis with lengthier follow-up. Additionally, 1- and 2-level procedures resulted in a 7.4% (95% CI 3.3%-11.4%) and15.6% (95 CI-9.2% to 40.4%) incidence of ASDegeneration, respectively. Although there was an 8.2% increase in ASDegeneration following 2-level operations (relative to 1-level), it did not reach statistical significance. We were unable to analyze ASDisease incidence following 2-level arthroplasty (too few cases), but 1-level operations resulted in an ASDisease incidence of 0.8% (95% CI 0.1%-1.5%)., Conclusions: This review represents a comprehensive estimation of the actual incidence of ASDegeneration and ASDisease across a heterogeneous group of surgeons, patients, and arthroplasty techniques. Our investigation should serve as a framework for individual surgeons to understand the impact of various cervical arthroplasty techniques, follow-up duration, and surgical levels on the incidence of ASDegeneration and ASDisease during the postoperative period., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Management of spine surgery patients with osteoporosis is challenging because of the difficulty of instrumenting and the potential complications, including nonunion and adjacent level fractures. Treatment of this patient population should involve a multidisciplinary approach including the spine surgeon, primary care physician, endocrinologist, and physical therapist. Indication for preoperative treatment before spinal fusion surgery is unclear. All patients should receive calcium and vitamin D. Hormone replacement therapy, including estrogen or selective estrogen receptor modulators, should be considered for elderly female patients with decreased bone mass. Bisphosphonates or intermittent parathyroid hormone are reserved for those with significant bone loss in the spine. Pretreatment with antiresorption medications affect bone remodeling, which is a vital part of graft incorporation and fusion. Although there have been numerous animal studies, there is limited clinical evidence. Accordingly, surgery should be delayed, if possible, to treat the osteoporosis before the intervention. Treatment may include bisphosphonates, as well as newer agents, such as recombinant parathyroid hormone. Further clinical data are needed to understand the relative advantages/disadvantage of antiresorptive vs anabolic agents, as well as the impact of administration of these medications before vs after fusion surgery. Future clinical studies will enable better understanding of the impact of current therapies on biomechanics and fusion outcomes in this unique and increasingly prevalent patient population.

Background Context: Anterior cervical discectomy and fusion (ACDF) and posterior cervical foraminotomy (PCF) are both used to surgically treat patients with cervical radiculopathy and have been shown to have similar outcomes. Nonetheless, ACDF has become increasingly more commonplace compared with PCF, in part because of a pervasive belief that PCF has a higher incidence of required reoperations., Purpose: To determine the reoperation rate at the index level of ACDF versus PCF 2 years postoperatively., Study Design: A retrospective case-control., Patient Sample: All patients that underwent ACDF and PCF for radiculopathy (excluding myelopathy indications) between January 2005 and December 2011., Outcome Measures: Revision surgery within 2 years, at the index level, was recorded., Methods: Propensity score analysis between the ACDF and PCF groups was done, matching for age, gender, race, body mass index, tobacco use, median income and insurance status, primary surgeon, level of surgery, surgery duration, and length of hospital stay., Results: Seven hundred ninety patients met the inclusion/exclusion criteria, including 627 ACDF and 163 PCF. Before propensity matching, the PCF group was found to be significantly older and more likely to be male. After matching, there were no significant differences between groups for any baseline characteristics. Reoperation rate at the index level was 4.8% for the ACDF group and 6.4% for the PCF group (p=.7) within 2 years of the initial surgery. Using equivalence testing, based on an a priori null hypothesis that a clinically meaningful difference between the two groups would be ≥5%, we found that the absolute difference of 1.6% was significantly (p=.01) less than our hypothesized difference., Conclusions: This study demonstrates that even after accounting for patient demographics, operative characteristics, and primary surgeon, there are no significant differences in 2-year reoperation rates at the index level between ACDF and PCF. The reoperation rates are statistically equivalent. Thus, spine surgeons can operate via the posterior approach without putting patients at increased risk for revision surgery at the index level., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Study Design: Retrospective chart review., Objective: To describe the adverse outcomes associated with the use of rhBMP-2 in thoracolumbar and lumbar fusions., Summary of Background Data: rhBMP-2 has been increasingly used in spinal fusions over the past decade. Early studies reported that the use of rhBMP-2 is associated with decreased operative time, blood loss, and pain scores, as well as improved fusion rates. Recent investigations have shown rhBMP-2 to be associated with various complications occurring at incidences ranging from 0% to 100%., Methods: Using the institutional electronic medical records, we retrospectively reviewed all patients between January 2002 and September 2010 that underwent thoracolumbar and lumbar spine fusion with BMP. Patient demographics, operative, and outcome/complication information was collected., Results: A total of 547 patient charts were reviewed with a mean follow-up time of 17 months. Mean age was 58 years. Forty-one percent of patients had undergone previous spine surgery. Thirty-nine percent of patients had a PLIF/TLIF, 29% underwent a PLF, and 20% an ALIF. No relevant differences in the patient characteristics and complications were identified between the various surgical approaches. For all approaches, having undergone a previous spine surgery was associated with increased incidence of radiculitis, reoperation, and pseudoarthrosis (P=0.005, 0.0008, 0.05, respectively) as compared with those without previous spine surgery. Being a current smoker at the time of operation was associated with increased rate of radiculitis (P=0.03) as compared with nonsmokers., Conclusions: The use of rhBMP-2, in this study, had an incidence of radiculitis, pseudoarthrosis, and reoperation that was similar to the rates in historical controls without rhBMP-2. Complications do not differ by surgical approach, but are more likely in current smokers and those undergoing revision surgery. A prospective study is warranted to further delineate the adverse event profile of rhBMP-2 and the variables that are likely to affect it (ie, type of surgery, carrier, and dose).

Background Context: In select patients, posterior cervical foraminotomy (PCF) and anterior cervical discectomy and fusion (ACDF) result in similar clinical outcomes when used to treat cervical radiculopathy. Nonetheless, ACDF is performed more frequently, in part because of surgeon perception that PCF requires operative revisions more frequently. The present study investigates the rate of ACDF reoperation at the index level after initial PCF., Purpose: To determine the rate of ACDF after initial PCF and to further describe any patient characteristics or preoperative or operative data that increase the rate of reoperation after PCF., Study Design: Retrospective chart review., Methods: Demographic, operative, and reoperation information was collected from the electronic medical records for all patients who underwent PCF at one institution between 2004 and 2011. All patients were subsequently contacted by telephone to identify postoperative complications and more conclusively determine whether any revision operation was performed at the index level., Results: One hundred seventy-eight patients who underwent a PCF were reviewed, with an average follow-up of 31.7 months. Nine (5%) patients underwent an ACDF revision operation at the index level. The reason for reoperation in these patients included cervical radiculopathy, foraminal stenosis, disc herniation, and cervical spondylosis. Patients who subsequently underwent ACDF at the index level were significantly younger (25 vs. 35 years, p=.03), had lower body mass index (25 vs. 29, p=.01), and more likely to take anxiolytic (56% vs. 22%, p=.04) or antidepressant medication (67% vs. 27%, p=.02), compared with those that did not have a revision operation., Conclusions: This is the first study to determine conversion to ACDF after PCF. The present study demonstrates that PCF is associated with a low reoperation rate, similar to the historical reoperation for ACDF. Accordingly, spine surgeons can operate via a PCF approach without a significant increased risk for ACDF revision surgery at the index level., (Published by Elsevier Inc.)

Background: Pedicle fractures in the cervical spine are common. They may occur in isolation or in combination with other concomitant fractures. Multiple classification systems have been introduced to provide a clinical framework when approaching these types of fractures; however, these systems do not provide guidelines for optimal treatment. Data regarding decision making are limited. Conservative treatment with orthoses may result in subluxation and instability requiring further treatment. Surgery may not be required in all instances because many of these injuries may heal without surgical intervention., Methods: All cases of cervical fractures treated at a single institution over a 5-year period were retrospectively reviewed. Cases with pedicle fractures were further evaluated, and 40 cases managed either with or without surgery were identified. Data on presenting history, neurologic examination, imaging findings, comorbidity, method of treatment, complication rate, and length of hospital stay were collected. Fractures were classified based on computed tomography scans. Data on associated injuries were also collected. Fusion rate and fracture displacement were assessed by plain radiographs and computed tomography scans at follow-up. Follow-up time points included 2, 6, and 12 weeks and 6 months after injury. Primary outcome was fracture healing regardless of modality in the absence of progressive deformity (i.e., listhesis, kyphosis) and need for further surgery., Results: Conservative therapy was administered to 26 patients, and 14 patients underwent surgery. There were no statistically significant differences between the 2 groups in terms of total levels injured (P = 0.9) or injury severity score (P = 0.5). Patients who presented with intact neurologic status were more likely to be treated conservatively (88% vs. 29%; P = 0.0004), whereas patients presenting with spinal cord injuries were more likely to undergo surgical fixation (35% vs. 0%; P = 0.0004). Length of hospital stay trended toward being significantly greater in patients who underwent surgery (10.6 days vs. 5.5 days; P = 0.07). According to our classification system, the most common fracture type was single line horizontal fracture occurring in 68% (27 of 40 cases). Vertical split pedicle fracture occurred in 28% (11 of 40 cases), and double line horizontal fracture occurred in 5% (2 of 40 cases). Posttreatment progressive listhesis was significantly higher in patients who were treated conservatively (31% vs. 0%; P = 0.03), especially when associated with comminuted lateral mass or subluxation or both., Conclusions: This study describes and classifies unique cervical pedicle fractures and associated injuries. Our findings suggest that surgical treatment results in definitive stability for these injuries compared with conservative therapy, particularly for pedicle fractures associated with comminuted lateral mass or initially displaced fractures. However, nondisplaced vertical split pedicle fractures and isolated single line horizontal fractures may be treated nonsurgically without occurrence of further instability. A larger prospective study is required to confirm these findings., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Object: The goal of this study was to compare the urological complications in patients after anterior lumbar interbody fusion (ALIF) with and without the use of recombinant human bone morphogenetic protein-2 (rhBMP-2)., Methods: The authors retrospectively reviewed the medical records of all patients who underwent ALIF with and without rhBMP-2 between January 2002 and August 2010. Patient demographic, operative, and complication information was analyzed. Male patients who underwent ALIF between L-4 and S-1 were contacted to assess postoperative urological complications., Results: Of the 110 male patients who underwent ALIF and were included in this study, 59 were treated with rhBMP-2 and 51 did not receive rhBMP-2. The mean follow-up duration was 17.5 months for the rhBMP-2 group and 30.8 months for the control group. No difference was found regarding the total number of urological complications in the rhBMP-2 group versus the control group (22% vs 20%, respectively; p = 1.0) or for retrograde ejaculation specifically (8% vs 8%, respectively; p = 1.0)., Conclusions: In this study, the use of rhBMP-2 with ALIF surgery was not associated with an increased incidence of urological complications and retrograde ejaculation when compared with control ALIF without rhBMP-2. Further prospective analyses that specifically look at these complications are warranted.

Study Design: A prospective clinical research article., Objective: The primary goals were to determine (1) radiation exposure to the spine surgeon with the use of an intraoperative 3-dimensional imaging system and (2) to define the safe distance from the computed tomographic scanner., Summary of Background: Intraoperative radiation exposure to the spinal surgeon has been assessed during 2-dimensional fluoroscopy but has not been investigated during intraoperative 3-dimensional imaging., Methods: Ten patients undergoing lumbar or thoracolumbar fusion were enrolled in a prospective trial to determine the radiation exposure to a spine surgeon standing in the substerile room, with the use of the O-ARM Imaging System (Medtronic, Memphis, TN). A thermolucent digital dosimeter was worn at chest level without a lead apron. Dosimeter readings and distance from the spine surgeon were recorded. RESULTS.: Average surgeon exposure was 44.22 ± 17.4 μrem (range: 17.71-70.76 μrem). The mean distance from the O-ARM was 4.56 ± .32 m, and the surgeon was exposed for an average of 19.6 ± 5.7 seconds (range: 8.05-28.7 s). The annual number of necessary procedures required to surpass the exposure limit, according to the data presented here, would be 113,071 operations using O-ARM. Hence, the number of necessary procedures for O-ARM use is predicted to be 1,130,710 annual procedures to reach the occupational exposure limits for extremity, skin, and all other organs and 339,213 procedures to reach the limits for the lens of eye., Conclusion: Radiation exposure is minimal to the surgical team during routine use of the O-ARM imaging system. The number of procedures required to surpass occupational exposure limits is high if using appropriate distance from the O-ARM.

Object: The theoretical advantage of pars interarticularis repair over spinal fusion to correct pars defects is that the treatment is a direct osteosynthesis that preserves motion at the involved functional spinal unit. Several techniques and constructs have been used to achieve greater rigidity, but these techniques may risk entry into the spinal canal, and adverse events are common. A pedicle and laminar screw construct placed entirely outside the spinal canal may offer greater stiffness and achieve higher pars defect healing rates. The purpose of this study was to biomechanically assess an intralaminar screw construct in cadaveric lumbar spines in comparison with other types of constructs typically used in pars repair and to quantify the sizes of screws that can be placed safely in both normal and spondylolytic vertebrae., Methods: The L-4 and L-5 laminae in patients with spondylolysis and in controls who underwent CT (n = 41, each group) were measured by analysis of conventional axial CT images and multiplanar reformations constructed on a Vitrea workstation to determine the feasibility of translaminar fixation with a 4.5-mm-diameter screw. Biomechanical tests for torsion and flexion-extension were performed on 8 fresh human cadaveric lumbar spines before and after modeling for bilateral spondylolytic defects. Three pars repair techniques were tested at each level and in the following sequence: pedicle screw-cable, pedicle screw-rod-hook, and pedicle screw-intralaminar screw., Results: The majority of laminae can accept 4.5 × 25-mm screws. The cable construct allowed the greatest motion and least stability across the defect in all biomechanical tests. The hook and laminar screw constructs performed similarly in all tests and exhibited no significant difference in stiffness., Conclusions: A surgically placed intralaminar screw construct may be a safe and effective alternative to current pars repair methods.

Background: Approaches to the foramen magnum and upper cervical spine traditionally include the posterior midline, far lateral, and endoscopic endonasal approaches. The far lateral approach is a well-established technique for the removal of pathology ventrolateral to the brainstem and the craniocervical junction, but it may be too extensive for lesions limited to areas far from the midline., Objective: To present an alternative to the commonly used approaches to the foramen magnum and upper cervical., Methods: We used an approach directly overlying ventral or lateral pathology., Results: Two cases are presented in which the direct lateral approach followed by an occipitocervical fusion was successfully performed., Conclusion: This approach can be considered for patients in whom a ventral decompression is necessary but an endoscopic endonasal approach is undesirable or when a ventral, lateral, and ventrolateral resection of tumor, pannus, or infection is required.

Study Design: Morphometric and volumetric analyses and virtual screw placement., Objective: The aim of the study was to (1) define the morphometric and volumetric dimensions of the laminae of C3-C7 and (2) analyze the feasibility of unilateral and bilateral translaminar screw placement at C3-C7., Summary of Background Data: Previous studies on translaminar screw fixation have primarily focused on upper cervical and thoracic fixation. Most studies have been conducted on the subaxial cervical vertebrae in the pediatric population and a few in the adult population. In this study, we used computed tomographic (CT) scans to calculate the spatial anatomical environment for translaminar screws at C3-C7. We also determined the feasibility of translaminar screw placement at C3-C7 for clinical applicability., Methods: Morphometric and volumetric analyses were performed on CT scans of the C3-C7 laminae in 25 male and 25 female patients. A total of 2000 morphometric and 1000 volumetric measurements were performed. The feasibility analysis was performed using unilateral and bilateral virtual screw placement via BrainLAB software (BrainLAB AG, Heimstetten, Germany) on the same CT scans., Results: Male patients had significantly (P < 0.05) longer translaminar lengths (C5-C7), sagittal-diagonal measurements (C3-C7), and larger volumes (C6-C7) than female patients. Unilaterally, C7 showed 3.5-mm translaminar screw acceptance rates of 100%, C6 showed high acceptance rates (>64%), and C3-C5 showed lower acceptance rates (<52%). C7 accepted bilateral placement at a high rate (96% men, 84% women). C3 and C6 accepted bilateral screws at low placement rates (8%-24%). C4 and C5 never accepted bilateral translaminar screw placement., Conclusion: Subaxial cervical unilateral translaminar screw placement is a potentially safe and effective technique to use in conjunction with preoperative CT scanning for all vertebral levels. The same is true for bilateral placement at C7 but not at C3-C6. A prospective study to evaluate the long-term outcomes of translaminar fixation at all vertebral levels is currently underway.

Study Design: Retrospective chart review., Objective: To assess the impact that routine postoperative radiographs have in clinical outcome and clinical decision-making., Summary of Background Data: No standard exists that outlines how often and when radiographs should be taken after lumbar fusion. Routine postoperative radiographs can be a source of inconvenience and cost to patients, radiation exposure, and possibly, confounding information., Methods: The patients who underwent a single or multilevel lumbar instrumented fusion were investigated. At each time-point after surgery, it was noted if they demonstrated new symptoms or clinical deterioration. The Fisher exact test was used to analyze the categorical data., Results: Sixty-three patients (25 males and 38 females) were identified with a mean age of 52 years (range, 20-87). Plain radiographs were taken at 269 visits including all time-points. In 17 (6.3%) visits, abnormal findings were found in 13 patients, including suspected pseudoarthrosis on radiographs (n = 10) and adjacent segment disease on radiographs (n = 3). They were found during 11 of 50 visits (22%) in the patients with new symptoms or clinical deterioration and during 6 of 219 visits (2.7%) in the asymptomatic patients. The probability of an abnormal finding was significantly lower in the asymptomatic patients (P < 0.001). Before the 6-month follow-up, abnormal findings were found in 1 of 111 visits (0.9%) and in 16 of 158 visits (10%) at the 6-month follow-up or later. The probability of an abnormal finding was significantly lower before the 6-month follow-up (P < 0.001). In six of the seven symptomatic patients (86%) with suspected pseudoarthrosis on radiographs, pseudoarthrosis was initially suspected between 6 and 12 months after surgery., Conclusion: This study suggests that plain radiographs should be performed as indicated clinically rather than routinely after instrumented lumbar fusion. The vast majority of asymptomatic patients do not require routine postoperative radiographs.

Study Design: Review of literature., Objective: To evaluate the available literature supporting the use of lumbar fusion extenders in clinical practice., Summary of Background Data: Because of the morbidity associated with the harvest of autologous iliac crest bone grafts, the search for lumber fusion extenders and replacements has accelerated. Many formulations of lumbar fusion extenders have been developed, and it is essential to evaluate clinical literature and available outcome metrics of these extenders., Methods: A review of English-language literature was performed between 1990 and January of 2010 for all literature presenting clinical outcomes of lumbar fusion extenders. After controlling for inclusion and exclusion criteria and assigning levels of evidence, 19 clinical studies were fully reviewed including those for demineralized bone matrix, recombinant human bone morphogenetic protein 2 (rhBMP-2), β-tricalcium phosphate, and calcium sulfate., Results: The most extensively studied of the lumbar fusion extenders is β-tricalcium phosphate, especially with regard to its use in adolescent scoliosis correction. The use of rhBMP-2 and demineralized bone matrix is supported only by two and three clinical studies, respectively. Calcium sulfate and other miscellaneous extenders are not conclusively or consistently supported by available clinical studies., Conclusion: Calcium phosphate is the most supported of the lumbar fusion extenders. rhBMP-2 and demineralized bone matrix are supported by smaller bodies of evidence. These formulations are supported by these initial studies but in some cases need to be better examined with regard to side effect profiles.

Ossification of the posterior longitudinal ligament is a common cause of radiculopathy and myelopathy that often requires surgery to achieve decompression of the neural elements. With the evolution of surgical technique and a greater understanding of the biomechanics of cervical deformity, the criteria for selecting one approach over the other has been the subject of increased study and remains controversial. Ventral approaches typically consist of variations of the cervical corpectomy, whereas dorsal approaches include a wide range of techniques including laminoplasty, laminectomy, and laminectomy with instrumented fusion. Herein, the features and limitations of these approaches are reviewed with an emphasis on complications and outcomes.

Object: The C-7 lateral mass has been considered difficult to fit with instrumentation because of its unique anatomy. Of the methods that exist for placing lateral mass screws, none particularly accommodates this anatomical variation. The authors have related 12 distinct morphological measures of the C-7 lateral mass to the ability to place a lateral mass screw using the Magerl, Roy-Camille, and a modified Roy-Camille method., Methods: Using CT scans, the authors performed virtual screw placement of lateral mass screws at the C-7 level in 25 male and 25 female patients. Complications recorded included foraminal and articular process violations, inability to achieve bony purchase, and inability to place a screw longer than 6 mm. Violations were monitored in the coronal, axial, and sagittal planes. The Roy-Camille technique was applied starting directly in the middle of the lateral mass, as defined by Pait's quadrants, with an axial angle of 15° lateral and a sagittal angle of 90°. The Magerl technique was performed by starting in the inferior portion of the top right square of Pait's quadrants and angling 25° laterally in the axial plane with a 45° cephalad angle in the sagittal plane. In a modified method, the starting point is similar to the Magerl technique in the top right square of Pait's quadrant and then angling 15° laterally in the axial plane. In the sagittal plane, a 90° angle is taken perpendicular to the dorsal portion of the lateral mass, as in the traditional Roy-Camille technique., Results: Of all the morphological methods analyzed, only a combined measure of intrusion of the T-1 facet and the overall length of the C-7 lateral mass was statistically associated with screw placement, and only in the Roy-Camille technique. Use of the Magerl technique allowed screw placement in 28 patients; use of the Roy-Camille technique allowed placement in 24 patients; and use of the modified technique allowed placement in 46 patients. No screw placement by any method was possible in 4 patients., Conclusions: There is only one distinct anatomical ratio that was shown to affect lateral mass screw placement at C-7. This ratio incorporates the overall length of the lateral mass and the amount of space occupied by the T-1 facet at C-7. Based on this virtual study, a modified Roy-Camille technique that utilizes a higher starting point may decrease the complication rate at C-7 by avoiding placement of the lateral mass screw into the T1 facet.

The craniovertebral junction is a complex region that incorporates the occiput-C1-C2 portions of the spine. It is a transition between the cranium and the mobile cervical spine that permits significant motion. The motions afforded and the anatomy are vastly different at the occiput-C1 and C1-C2 articulations. These differences make treating pathology in this region very difficult. Problems include bony fixation of the cranium and the cervical spine (specifically C1 and C2), which limits complex motions, and limited bony sites available for arthrodesis. A thorough knowledge of the normal anatomy and biomechanics is required for fixation of this region. Moreover, an understanding of pathologic motions and the biomechanics of fixation is needed for successful construct design and good patient outcome.

Background: In today's health-care environment, operational efficiency is intrinsic to balancing the need for increased productivity driven by rising costs and potentially decreasing reimbursement. Other operational factors kept constant, decreasing the time for a procedure can be viewed as one marker for increased efficiency., Purpose: To prospectively evaluate the time and operating room efficiency differences between the two methods for intraoperative level localization. STYDY DESIGN: Prospective nonrandomized study., Patient Sample: Prospective consecutive patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) with plate and allograft., Outcomes Measures: Time for performance and interpretation of intraoperative localization radiograph., Methods: This is a prospective nonrandomized study of patients treated consecutively with a single-level ACDF with allograft and plating. All the patients underwent a conventional approach to the cervical spine. After exposure, a spinal needle was placed in the exposed intervertebral disc and a radiography was performed. Either a conventional or a digital radiography was used in each case., Results: Eighteen patients were enrolled in this study. Ten patients underwent localization with conventional radiography, whereas eight patients underwent localization with digital imaging. The mean time for conventional radiography was 823 seconds (standard deviation [SD], 159), and for digital, it was 100 seconds (SD, 34; p<.001)., Conclusions: Current technology provides options for level localization. Digital imaging provides equally accurate information as conventional radiography in a significantly reduced amount of time. Image quality, ease or archival, and manipulation provided by digital radiography are superior to those by provided fluoroscopy. Keeping operational factors constant, decreasing the time for a procedure, and increasing the efficiency of the environment may be viewed as a surrogate for improving the cost basis for a procedure.

Background: Evidence-based clinical practice requires the incorporation of information available in the medical literature into clinical decision making. Reliance on randomized trials as criteria for making recommendations is usually impractical. Conclusions based on low-quality information or post hoc analysis of high-quality information must be interpreted with caution., Purpose: To present a clinical research "case report" as means to describe common pitfalls faced by authors, editors, and readers of the medical literature with a focus on spinal surgery., Study Design/setting: This article describes a historical cohort study performed at a university hospital., Patient Sample: One hundred thirty-eight consecutive patients treated with single-level anterior cervical discectomy and fusion (ACDF) by a single surgeon., Outcomes Measure: The primary outcome measure was the need for reoperation., Methods: The authors performed a retrospective cohort comparison of 138 consecutive patients treated with single-level ACDF using either constrained or translational plates. The primary outcome measure of interest was the need for reoperation at the index or adjacent level. The mean follow-up exceeded 3 years in both groups., Results: Patients treated with a single-level ACDF using a translational plate had a decreased incidence of reoperation compared with those treated with a constrained plate (1.6% translational, 12% constrained). This result was initially felt to be statistically significant when analyzed primarily (p<.05). When further analysis was used to account for potential differences in the patient populations, the significance of this result was lost (p=.16)., Conclusions: Faulty study design or overaggressive statistical data mining leads to unreliable conclusions. It is important that practicing spinal surgeons appreciate the perils and pitfalls of interpretation of the medical literature. Common sense, clinical experience, and healthy skepticism are indispensable for the rational incorporation of lesser quality information from the medical literature into clinical decision making.

Study Design: A retrospective chart review of all patients who underwent posterior cervical fusion during a 1-year time period., Objective: To analyze the safety profile of recombinant human bone morphogenetic protein (rhBMP)-2 in posterior cervical fusion., Summary of Background Data: Use of rhBMP-2 in anterior cervical spine surgery has been associated with complications including postoperative edema, dysphagia, and hematoma formation. No literature exists regarding the safety of rhBMP-2 use for posterior cervical fusion., Methods: We reviewed all posterior cervical fusions performed during 1 year at our hospital following institutional review board permission., Results: A total of 83 patients underwent posterior cervical fusion. Sixty-seven (81%) did not receive rhBMP (control group), whereas 16 (19%) underwent fusion with rhBMP. The most common reason for the use of rhBMP was a failure of an anterior cervical fusion resulting in persistent neck pain, myelopathy, or radiculopathy. The average dose of rhBMP used was 1.3 mL per level. Immediate postoperative medical complications occurred in 5 (7%) in the control group and 2 (13%) in the rhBMP group. A new neurologic deficit after surgery was found in 3 (4%) in the control group and 1 (6%) in the rhBMP group. Wound infection requiring further surgery occurred in 8 (12%) in the control group, and in none in the rhBMP group. One (6%) patient in the rhBMP group had significant postoperative neck swelling, but improved with steroid treatment over 1 week, and without any compromise of vital neck structures. No postoperative hematomas were seen in either group. Chi2 analysis revealed that no complication variable reached significance (P < 0.05) when the 2 groups were compared., Conclusion: rhBMP can safely be used in patients undergoing posterior cervical fusion, as it does not produce complications at the rate previously seen with its use in the anterior cervical spine.

Objective: Patients with cervical radiculopathy and/or myelopathy are often treated with anterior cervical discectomy and fusion. Cervical arthroplasty has recently been advocated as an alternative treatment. Theoretically, arthroplasty should permit early return to activity and protect against adjacent segment disease. Early mobilization and return to activity may, theoretically, reduce cost to the workers' compensation program., Methods: A subgroup analysis of workers' compensation patients from the randomized controlled trials comparing Prestige ST and Bryan (Medtronic Sofamor Danek, Memphis, TN) cervical arthroplasty to fusion was performed. Primary outcome measures were work status, time to return to work, and neck disability. Secondary outcome measures were neck and arm pain and Medical Outcomes Study Short-Form 36-Item Health Survey score., Results: One thousand four patients were enrolled in the studies, 93 of whom were workers' compensation patients. At 6 weeks and 3 months, significantly more patients in the arthroplasty group were working compared with the fusion group. At 6 months and later, there was no significant difference in return-to-work rates. Overall, patients returned to work at a median of 101 days after arthroplasty, compared with 222 days after anterior cervical discectomy and fusion. This difference was not significant when controlling for sex, study, and preoperative work status. At all time points, the Neck Disability Index was consistently lower in the arthroplasty group compared with the fusion group; however, the difference was not significant at 24 months. There was no statistically significant difference in secondary outcomes, neurological events, or pain-related events., Conclusion: In this workers' compensation cohort, it was observed that a greater number of patients in the arthroplasty group returned to work at 6 weeks and 3 months after surgery. A trend toward an earlier return to work was also seen, although this was not statistically significant when controlling for differences in the studies.

Spinal instrumentation for the correction of spinal deformity began with Harrington and his rod system. The use of the Harrington rods was limited, however, because of the need for long-segment instrumentation, distraction, and the potential for hood dislodgment and construct failure. Luque subsequently introduced the next generation of spinal fixation techniques via the concept of segmental instrumentation; his use of sublaminar wires allowed the construct to be fixated to the spine at every level. This arrangement allowed greater control over correction of spinal deformities and significantly lessened the incidence of hardware dislodgment. Modern instrumentation systems, including the use of pedicle screws, permit even greater control of the spine in multiple planes during deformity correction. Newer strategies have decreased the incidence of neurological injury during implant application and provide greater stability. A review of segmental fixation, including surgical techniques, is provided in this article.

Object: Pseudarthrosis and construct failure following single-level anterior cervical discectomy, fusion, and plate placement (ACDFP) rarely occur. Routine postoperative anteroposterior and lateral radiographs may be an inconvenience to patients and expose them to additional and potentially unnecessary radiation. No standard exists to define when patients should obtain radiographs following an ACDFP. The authors hypothesize that routinely obtaining static anteroposterior and lateral radiographs in patients who recently underwent a single-level ACDFP without new axial neck pain or other neurological complaints or symptoms is unwarranted and does not alter the long-term treatment of the patient., Methods: The authors retrospectively reviewed the charts and radiographs of patients who underwent a single-level ACDFP between January 1, 2000, and December 31, 2005. All patients underwent a single-level ACDFP and had routine cervical radiographs obtained at various intervals after surgery., Results: Twenty-one patients underwent ACDFP at C5-6, 14 patients underwent surgery at C6-7, 11 patients at C4-5, and 7 patients at C3-4. None of the intraoperative radiographs demonstrated malposition of the graft or instrumentation. Based on subjective reporting by the patients, the vast majority (49 of 53) showed improvement in neck and arm pain, and/or neurological dysfunction following surgery. Overall, 5 patients (9%) demonstrated abnormalities on their postoperative radiographs. No patients were returned to the operating room as a result of postoperative radiographic findings. The sensitivity of plain radiographs in this patient series or the percentage of patients with new symptoms that had an abnormality related to the construct on plain radiography was 50%. The specificity of plain radiographs or the percentage of patients who were asymptomatic and had normal radiographs was 94%. The positive predictive value was 25%; that is, there was a 25% chance that patients with symptoms would have a construct abnormality on postoperative radiographs. The negative predictive value was 98%; that is, 98% of patients without symptoms will have normal radiographs., Conclusions: Pseudarthrosis and construct failure following single-level ACDFP occur rarely, and patients with new symptoms following surgery are as likely to have normal radiographic findings as they are to have abnormalities identified on their postoperative plain radiographs. Routinely obtaining postoperative radiographs at regular intervals in asymptomatic patients following single-level ACDFP does not appear to be warranted.

Objective: Interbody lumbar fusion techniques have become increasingly popular because of improved rates of fusion, restoration of disc and foraminal height, and promotion of lordosis. Morbidity has been associated with the exposure for these fusions, potentially leading to muscle injury, trunk muscle weakness, and pain. Minimal access surgery has been advocated to limit the exposure related morbidity. Tubular retractors are available, which allow dilation of the muscle through a small incision. The downside of these dilators is the expense required to use them and a generally cumbersome design, which can limit mobility and medial/lateral exposure., Methods: The authors report their experience with a standard ventral cervical retractor system for minimal access transforaminal lumbar interbody fusion. These systems are already owned by the hospital and are familiar to most spine surgeons., Results: The system is placed through a fascial plane between muscles, eliminating muscle dissection and limiting undue retraction and tissue destruction., Conclusion: A standard ventral cervical retractor may be used to perform minimal access transforaminal lumbar interbody fusion. The exposure is as good as or better than tubular retractor systems commercially available. There may be considerable cost savings owing to the elimination of the need for yet another specialized piece of equipment in the operating room. Time may also be saved, as spine surgeons are already adept in the use of such retractors.