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STUDY DESIGN.: Experimental, human cadaveric study. OBJECTIVE.: To assess the fixation effects of injecting cement augmentation before screw insertion or after insertion of fenestrated screws; the effect of modulating cement viscosity; and the effects of these techniques on screw removal. SUMMARY OF BACKGROUND DATA.: It seems clear that cement augmentation can enhance pedicle screw fixation in osteoporotic bone. What remains to be demonstrated is the aspects of optimal technique such that fixation is enhanced with the greatest safety profile. METHODS.: Part I: Human osteoporotic vertebrae were instrumented with solid (nonaugmented) screws, solid screws with polymethylmethacrylate (PMMA), partially cannulated fenestrated (Pfen) screws, or fully cannulated fenestrated (Ffen) screws through which PMMA was injected. Screw fixation was tested in pullout. Part II: Ffen screws were augmented with standard low-viscosity PMMA versus high-viscosity PMMA. Part III: Sample cohorts were extracted from vertebrae to assess required torque and characterize difficulty of extraction. RESULTS.: Part I: Pfen screws demonstrated the greatest fixation with mean failure force of 690 ± 182 N. All methods of cement augmentation demonstrated significant increases in screw fixation. Part II: Ffen screws did not demonstrate a significant difference in pullout strength when high-viscosity PMMA was used as compared with low-viscosity PMMA. Part III: Mean extraction torque values for solid augmented screws, Ffen screws, and Pfen screws were 1.167, 1.764, and 1.794 Nm, respectively, but these differences did not reach significance. None of the osteoporotic vertebrae sustained catastrophic failure during augmented screw extraction. CONCLUSION.: Polymethylmethacrylate cement augmentation clearly enhances pedicle screw fixation in osteoporotic vertebrae when tested in pure pullout. The technique used for cement injection and choice of specialty screws can have a significant impact on the magnitude of this effect. Fenestrated screws have the capacity to confine cement placement in the vertebral body and may provide enhanced safety from cement extrusion into the spinal canal. It is feasible to inject high-viscosity PMMA through this fenestration geometry, and higher-viscosity cement may enhance the fixation effect. [ABSTRACT FROM AUTHOR]

STUDY DESIGN.: Systematic review of literature focused on heterogeneity of treatment effect analysis. OBJECTIVE.: The objectives of this systematic review were to determine if comorbid disease and general health factors modify the effect of fusion versus nonoperative management in chronic low back pain (CLBP) patients? SUMMARY OF BACKGROUND DATA.: Surgical fusion as a treatment of back pain continues to be controversial due to inconsistent responses to treatment. The reasons for this are multifactorial but may include heterogeneity in the patient population and in surgeon's attitudes and approaches to this complex problem. There is a relative paucity of high quality publications from which to draw conclusions. We were interested in investigating the possibility of detecting treatment response differences comparing fusion to conservative management for CLBP among subpopulations with different disease specific and general health risk factors. METHODS.: A systematic search was conducted in MEDLINE and the Cochrane Collaboration Library for literature published from 1990 through December 2010. To evaluate whether the effects of CLBP treatment varied by disease or general health subgroups, we sought randomized controlled trials or nonrandomized observational studies with concurrent controls evaluating surgical fusion versus nonoperative management for CLBP. Of the original 127 citations identified, only 5 reported treatment effects (fusion vs. conservative management) separately by disease and general health subgroups of interest. Of those, only two focused on patients who had primarily back pain without spinal stenosis or spondylolisthesis. RESULTS.: Few studies comparing fusion to nonoperative management reported differences in outcome by specific disease or general health subpopulations. Among those that did, we observed the effect of fusion compared to nonoperative management was slightly more favorable in patients with no additional comorbidities compared with those with additional comorbidities and more marked in nonsmokers compared with smokers. CONCLUSION.: It is unclear from the literature which patients are the best candidates for fusion versus conservative management when experiencing CLBP without significant neurological impairment. Nonsmokers may be more likely to have a favorable surgical fusion outcome in CLBP patients. Comorbid disease presence has not been shown to definitively modify the effect of fusion. Further prospective studies that are designed to evaluate these and other subgroup effects are encouraged to confirm these findings. CLINICAL RECOMMENDATIONS.: We recommend optimizing the management of medical co-morbidities and smoking cessation before considering surgical fusion in CLBP patients. Strength of recommendation: Weak. [ABSTRACT FROM AUTHOR]

Background: In a large teaching institution with providers of various levels of training and backgrounds, and a coding department responsible for all evaluation and management (E&M) billing, variations in documentation can hinder accurate medical management and compensation. The purpose of this study is to assess differences in re-imbursement between templated and non-templated outpatient documentation for patients who eventually underwent single level lumbar microdiscectomy and anterior cervical discectomy and fusion (ACDF) both before and after the E&M billing changes were implemented in 2021., Methods: Data was collected from three spine surgeons on 41 patients who underwent a single level lumbar microdiscectomy at a tertiary care center from July 2018 to June 2019 and 35 patients seen by four spine surgeons from January through December of 2021 given the new E&M billing changes. ACDF data was collected for 52 patients between 2018 and 2019 for three spine surgeons and 30 patients from January through December of 2021 from four spine surgeons. Billing level was decided by independent coders for preoperative visits., Results: During the study period from 2018-2019 for lumbar microdiscectomy, each surgeon averaged about 14 patients. Results showed variability of billing level between the three spine surgeons (surgeon 1, 3.2±0.4; surgeon 2, 3.5±0.6; and surgeon 3, 2.9±0.8). Interestingly, even after the implementation of the 2021 E&M billing changes, there was a statistically significant increased level of billing for templated notes for lumbar microdiscectomy (P=0.013). However, this did not translate to the clinic visits for patients who underwent ACDF in 2021. When data was aggregated for all the patients from 2021 who either underwent lumbar microdiscectomy or ACDF, using a template still resulted in a statistically significant higher level of billing (P<0.05)., Conclusions: Utilization of templates for clinical documentation reduces variability in billing codes. This impacts subsequent reimbursements and potentially prevents significant financial losses at large tertiary care facilities., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-22-91/coif). The authors have no conflicts of interest to declare., (2023 Journal of Spine Surgery. All rights reserved.)

Introduction: Symptomatic disc degeneration is a common cause of low back pain. Recently, the prevalence of low back pain has swiftly risen leading to increased patient disability and loss of work. The increase in back pain also coincides with a rapid rise in patient medical comorbidities. However, a comprehensive study evaluating a link between patient's medical comorbidities and their influence on lumbar intervertebral disc morphology is lacking in the literature., Methods: Electronic medical records (EMR) were retrospectively reviewed to determine patient-specific medical characteristics. Magnetic resonance imaging (MRI) was evaluated for lumbar spine intervertebral disc desiccation and height loss according to the Griffith-modified Pfirrmann grading system. Bivariate and multivariable linear regression analyses assessed strength of associations between patient characteristics and lumbar spine Pfirrmann grade severity (Pfirrmann grade of the most affected lumbar spine intervertebral disc) and cumulative grades (summed Pfirrmann grades for all lumbar spine intervertebral discs)., Results: In total, 605 patients (304 diabetics and 301 non-diabetics) met inclusion criteria. Bivariate analysis identified older age, diabetes, American Society of Anesthesiologists (ASA) class, hypertension, chronic obstructive pulmonary disease (COPD), peripheral vascular disease, and hypothyroidism as being strongly associated with an increasing cumulative Pfirrmann grades. Multivariable models similarly found an association linking increased cumulative Pfirrmann grades with diabetes, hypothyroidism, and hypertension, while additionally identifying non-white race, heart disease, and previous lumbar surgery. Chronic pain, depression, and obstructive sleep apnea (OSA) were associated with increased Pfirrmann grades at the most affected level without an increase in cumulative Pfirrmann scores. Glucose control was not associated with increasing severity or cumulative Pfirrmann scores., Conclusion: These findings provide specific targets for future studies to elucidate key mechanisms by which patient-specific medical characteristics contribute to the development and progression of lumbar spine disc desiccation and height loss., Level of Evidence: III (retrospective cohort)., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Study Design: Retrospective study., Purpose: To identify the rate of positive acid-fast bacillus (AFB) and fungal cultures during spine debridement, determine whether these infections are more common in certain spine segments, identify comorbidities associated with these infections, and determine whether the universal performance of fungal and AFB cultures during spine debridement is cost effective., Overview of Literature: Spine infections are associated with significant morbidity and costs. Spine fungal and AFB infections are rare, but their incidence has not been well documented. As such, guidance regarding sample procurement for AFB and fungal cultures is lacking., Methods: A retrospective review of medical record data from patients undergoing spine irrigation and debridement (I&D) at the University of Missouri over a 10-year period was performed., Results: For patients undergoing spine I&D, there was a 4% incidence of fungal infection and 0.49% rate of AFB infection. Steroid use was associated with a higher likelihood (odds ratio, 5.62; 95% confidence interval, 1.33-23.75) of positive fungal or AFB cultures. Although not significant, patients undergoing multiple I&D procedures had higher rates of positive fungal cultures during each subsequent I&D. Over a 10-year period, if fungal cultures are obtained for each patient, it would cost our healthcare system $12,151.58. This is compared to an average cost of $177,297.64 per missed fungal infection requiring subsequent treatment., Conclusions: Spine fungal infections occur infrequently at a rate of 4%. Physicians should strongly consider obtaining samples for fungal cultures in patients undergoing spine I&D, especially those using steroids and those undergoing multiple I&Ds. Our AFB culture rates mirror the false positive rates seen in previous orthopedic literature. It is unlikely to be cost effective to send for AFB cultures in areas with low endemic rates of AFB.

Study Design: This was a retrospective cohort study., Objective: The objective of this study was to quantify the rates of complication following surgical treatment for symptomatic degenerative and isthmic spondylolisthesis and to examine the association between slip reduction and complication rates., Summary of Background Data: It is unclear if the degree of spondylolisthesis reduction during lumbar spine fusion in adults influences the rate of surgical complications., Methods: This is a retrospective cohort study of 1-level and 2-level adult fusion patients with degenerative or isthmic spondylolisthesis. The degree of reduction and complications were calculated, and complication rates between those with and without reduction were compared., Results: The surgical reduction was improved by 1 Meyerding grade in 56.5% of the 140 patients included in this analysis. Of those patients, 60% had a grade 1 spondylolisthesis. In addition, 62.5% of grade 2 slips had an improvement by 1 grade. Surgical reduction during lumbar fusion did not result in a higher rate of complications compared with in situ fusion., Conclusions: During 1-level or 2-level lumbar fusion for degenerative or isthmic spondylolisthesis, a 1-grade reduction of the slip was achieved in 56% of patients in this retrospective case series. Reduction of the spondylolisthesis was not associated with a higher rate of complication when compared with in situ fusion., Level of Evidence: Level IV., Competing Interests: C.L.G. is a board or committee member at AOSpine North America, North American Spine Society. E.V.L. is on the editorial or governing board at JISAKOS, Journal of Knee Surgery. J.L.C. received IP royalties and research support from Arthrex Inc.; is a paid consultant; paid presenter, or speaker at Arthrex Inc.; is a paid consultant at Bioventus; received research support from Coulter Foundation, DePuy Synthes—A Johnson & Johnson Company, GE Healthcare, Merial; is on the editorial or governing board at Journal of Knee Surgery; is a board or committee member at Midwest Transplant Network, Musculoskeletal Transplant Foundation and received IP royalties, research support; received research support from National Institutes of Health (NIAMS & NICHD), Purina, US Department of Defense; received publishing royalties, financial, or material support from Thieme: is a paid consultant at Trupanion. T.J.C. is a board or committee member at AOSpine North America, North American Spine Society, Scoliosis Research Society; received stock or stock options from Gentis Inc. The remaining authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Controlled laboratory study., Objective: To investigate the impact of exposure to physiologically relevant caffeine concentrations on intervertebral disc (IVD) cell viability and extracellular matrix composition (ECM) in a whole organ culture model as potential contributing mechanisms in development and progression of IVD disorders in humans. Primary outcome measures were IVD viable cell density (VCD) and ECM composition., Methods: A total of 190 IVD whole organ explants from tails of 16 skeletally mature rats-consisting of cranial body half, endplate, IVD, endplate, and caudal body half-were harvested. IVD explants were randomly assigned to 1 of 2 groups: uninjured (n = 90) or injured (20G needle disc puncture/aspiration method, n = 100). Explants from each group were randomly assigned to 1 of 3 treatment groups: low caffeine (LCAF: 5 mg/L), moderate caffeine (MCAF: 10 mg/L), and high caffeine (HCAF: 15 mg/L) concentrations., Results: Cell viability was significantly higher in the low-caffeine group compared with the high-caffeine group at day 7 ( P = .037) and in the low-caffeine group compared with the medium- and high-caffeine groups at day 21 ( P ≤ .004). Analysis of ECM showed that all uninjured and control groups had significantly higher ( P < .05) glycosaminoglycan concentrations compared with all injured groups. Furthermore, we observed a temporal, downward trend in proteoglycan to collagen ratio for the caffeine groups., Conclusions: Caffeine intake may be a risk factor for IVD degeneration, especially in conjunction with disc injury. Mechanisms for caffeine associated disc degeneration may involve cell and ECM, and further studies should elucidate mechanistic pathways and potential benefits for caffeine restriction.

Aim: To evaluate the effect of sugammadex compared with neostigmine on speed and quality of recovery after rocuronium neuromuscular blockade (NMB) in geriatric patients undergoing posterior lumbar spine surgery., Methods: This randomized controlled study at a tertiary academic medical center involved 40 patients (age ≥65 years, ASA PS II/III) scheduled for elective surgery under general anesthesia. Patients were randomized to sugammadex or neostigmine for reversal of moderate NMB with rocuronium. The primary outcome was recovery time from NMB after surgery to a train-of-four (TOF) ratio ≥0.9 measured at the adductor pollicis (TOF-Watch® SX). Secondary outcomes included hemodynamic change after administration of reversal agent (heart rate, blood pressure, dysrhythmia), time to extubation, pain medication requirement, time to first ambulation, and length of postanesthesia care unit (PACU) and total hospital stay., Results: Sugammadex (4±2.2 min) compared with neostigmine reversal (26.3±17.5 min) was on average 22 min faster (95% CI 14.1-30.5; P≤0.001) with less variability (range 2-11 min vs 5-72 min). The groups significantly differed in time for tracheal extubation, response to verbal commands (open eyes, squeeze hand, lift head), and operating room exit. However, they had similar PACU stay, time to first ambulation, total hospital stay, postoperative pain, and opioid use. Sugammadex had less hemodynamic variability than neostigmine. No patient developed treatment-emergent dysrhythmias., Conclusion: Sugammadex reversal significantly hastened NMB recovery compared with neostigmine reversal in geriatric patients. It significantly decreased operating room time but not PACU time or hospital stay.

Background Context: Vertebral osteomyelitis (VO) becomes increasingly more prevalent as people age, and it is a condition seen frequently by referral center spine surgeons. It can take as long as 6 months for a proper diagnosis to be made. Staphylococcus aureus (S. aureus) is the most common isolated organism in up to 80% of the affected population. The clinical presentation of vertebral osteomyelitis is typically non specific (back pain), which can make timely diagnosis challenging. Fever is often absent. Serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell count (WBC) and serum polymorphonuclear leukocyte percentage (PMN%) are traditionally used as first-line tests because of their perceived sensitivity to help diagnose vertebral osteomyelitis. It is not known whether these test values are affected by the infecting organism., Purpose: To determine whether individual first-line diagnostics differed based on infecting organism and whether certain organisms are associated with lower lab values. Additionally, this study sought to determine if VO caused by lower virulent (eg, culture-negative and nonpyogenic organisms) could contribute to delays in treatment due to lack of elevated biomarkers., Study Design/setting: Single-center retrospective cohort study., Patient Sample: We reviewed clinical data of 133 patients (60% male) diagnosed with VO from 2015-2019 in a US Midwest academic hospital., Outcomes Measures: Primary outcome measures included the maximum temperature upon presentation, serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell count (WBC), and percentage neutrophils during the hospital admission., Methods: Inclusion criteria were adult patients diagnosed with vertebral osteomyelitis who underwent blood culture and/or biopsy prior to treatment. All patients enrolled in the study were diagnosed with VO and confirmed via magnetic resonance imaging (MRI). MRI findings associated with VO included destruction of endplates, increased signal in vertebral bodies, and the surrounding disc on T2-weighted imaging were confirmed. The patients had laboratory work up and clinical follow up regardless of positive culture or negative culture. The mean peak inflammatory marker levels were compared among organisms with student's t test. Demographics, comorbidities, and CCI were collected and multivariable logistic regression models were used. Receiver operating characteristic curve analysis was performed to delineate separate, optimal cut offs for CRP, ESR, WBC, and PMN% for patients with culture positive osteomyelitis RESULTS: Patients' average age was 57.0±13.7 years with a mean BMI of 30.5±9.70 kg/m 2 , and a mean Charleston Comorbidity Index (CCI) of 3.17±2.35. Staphylococcus aureus and antibiotic resistant organisms (MRSA and VRE) demonstrated a higher mean CRP and ESR than culture negative, fungal and TB cases. Staphylococcus aureus, antibiotic resistant organisms, and coagulase negative Staphylococcus demonstrated a higher mean WBC than culture negative as well as fungal and TB cases. Staphylococcus aureus, antibiotic resistant organisms, coagulase negative Staphylococcus, and Streptococcus species had a higher mean peak PMN%, than culture negative as well as fungal and TB case. Temperature did not correlate with a diagnosis of osteomyelitis., Conclusions: Serum laboratory markers in the diagnosis of VO appear to be influenced by the infecting organism type. Laboratory values in patients diagnosed with VO with culture negative or non-pyogenic organisms are lower compared to antibiotic resistant and S. aureus organisms. Fever did not correlate with a diagnosis of VO., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Determining important links between medical comorbidities and cervical spine degenerative disc disease (DDD) will help elucidate pathomechanisms of disc degeneration. Electronic medical records and magnetic resonance imaging were retrospectively reviewed to evaluate 799 patients assessed for cervical spine pathology. Bivariate analysis identified older age, diabetes, ASA class, cancer, COPD, depression, hypertension, hypothyroidism, Medicare status, peripheral vascular disease, history of previous cervical spine surgery, smoking, and lower median household income as having strong associations with increased cumulative grade of cervical spine DDD. This study provides evidence suggesting aging and accumulation of medical comorbidities influence severity of cervical spine DDD., (© 2021 Professor P K Surendran Memorial Education Foundation. Published by Elsevier B.V. All rights reserved.)

Cystic fibrosis (CF) is a relatively common disease seen in Whites of northern European descent. Classically, it was a lethal disease and uncommon for the orthopedic practitioner to interact with CF patients. Recent pharmaceutical breakthroughs targeting the CF transmembrane conductance regulator (CFTR) gene have significantly prolonged patient life expectancy. This makes it increasingly likely that orthopedic surgeons will encounter CF patients in their clinic. In this article, the authors discuss pertinent musculoskeletal manifestations of the CF population, including the increased risk of decreased bone mineral density and bone mineral content, muscle deconditioning, spinal kyphosis, fractures, and elevated systemic inflammation predisposing these individuals to CF-related arthralgia. The diagnoses are grouped into subspecialties (arthroplasty, pediatrics, spine, sports, and trauma) most likely to evaluate the patient. Additionally, the authors review treatment options for these conditions and discuss the need for these patients to be seen in the perioperative period by their CF care team for patient optimization due to their diminished pulmonary function. Interspersed with this literature review, the authors present 2 unique cases. The first case details a patient with pain over her spine due to multilevel spinous process bursitis caused by a high-frequency chest wall oscillation system, which masquerades as an infection. The second case is a non-contact midsubstance rectus femoris tear in an athlete. These cases highlight the need for increased vigilance for uncommon diagnoses in the CF patient population. [ Orthopedics . 2021;44(3):e440-e445.].

Neck and low back pain are common among the adult human population and impose large social and economic burdens on health care and quality of life. Spine-related disorders are also significant health concerns for canine companions with etiopathogeneses, clinical presentations, and diagnostic and therapeutic options that are very similar to their human counterparts. Historically, induced and spontaneous pathology in laboratory rodents, dogs, sheep, goats, pigs, and nonhuman primates have been used for study of human spine disorders. While each of these can serve as useful preclinical models, they all have inherent limitations. Spontaneously occurring spine disorders in dogs provide highly translatable data that overcome many of the limitations of other models and have the added benefit of contributing to veterinary healthcare as well. For this scoping review, peer-reviewed manuscripts were selected from PubMed and Google Scholar searches using keywords: "intervertebral disc," "intervertebral disc degeneration," "biomarkers," "histopathology," "canine," and "mechanism." Additional keywords such as "injury," "induced model," and "nucleus degeneration" were used to further narrow inclusion. The objectives of this review were to (a) outline similarities in key features of spine disorders between dogs and humans; (b) describe relevant canine models; and (c) highlight the applicability of these models for advancing translational research and clinical application for mechanisms of disease, diagnosis, prognosis, prevention, and treatment, with a focus on intervertebral disc degeneration. Best current evidence suggests that dogs share important anatomical, physiological, histological, and molecular components of spinal disorders in humans, such that induced and spontaneous canine models can be very effective for translational research. Taken together, the peer-reviewed literature supports numerous advantages for use of canine models for study of disorders of the spine when the potential limitations and challenges are addressed., Competing Interests: The following authors have the following declarations: Naomi N. Lee: No conflicts to declare; Jacob S. Kramer: No conflicts to declare; Aaron M. Stoker: Arthrex, Inc: IP royalties; Other financial or material support; Musculoskeletal Transplant Foundation: IP royalties; Chantelle C. Bozynski: No conflicts to declare; Cristi R. Cook: Arthrex, Inc: IP royalties; Paid consultant; Paid presenter or speaker; Research support CONMED Linvatec: IP royalties; Paid consultant; Paid presenter or speaker Musculoskeletal Transplant Foundation: IP royalties; Paid presenter or speaker Zimmer: Research support; James T. Stannard: No conflicts to declare; Theodore J. Choma: AO Spine North America: Board or committee member Gentis, Inc: Stock or stock Options North American Spine Society: Board or committee member Scoliosis Research Society: Board or committee member; James L. Cook: Artelon: Paid consultant Arthrex, Inc: IP royalties; Paid consultant; Paid presenter or speaker; Research support AthleteIQ: IP royalties ConforMIS: Research support CONMED Linvatec: Paid consultant Coulter Foundation: Research support DePuy Synthes, A Johnson & Johnson Company: Research support Eli Lilly: Paid consultant; Research support Journal of Knee Surgery: Editorial or governing board Merial: Research support Midwest Transplant Network: Board or committee member Musculoskeletal Transplant Foundation: Board or committee member; IP royalties; Research support National Institutes of Health (NIAMS & NICHD): Research support Purina: Research support Schwartz Biomedical: Paid consultant Thieme: Publishing royalties, financial or material support Trupanion: Paid consultant U.S. Department of Defense: Research support Zimmer‐Biomet: Research support. Note: Authors James L. Cook and Cristi R. Cook are husband and wife., (© 2020 The Authors. JOR Spine published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Background: While there are several different animal models for use in the characterization of spinal fixation, none have emerged as a definitive model for comparative studies in spinal fixation methods. The purpose of this study is to establish morphometric data of porcine vertebrae and to characterize the feasibility of pedicle screw fixation in porcine spines for potential comparative human study., Methods: Four spines from 45 to 50 kg Hanford minipigs were cleaned of soft tissue and analyzed by computed tomography and dual-energy x-ray absorptiometry. Two 5 × 30-mm pedicle screws were placed in each vertebra and tested to failure using a combined moment-load protocol., Results: Pedicle widths were measured from L6-T5. Widths ranged from 7.15 mm (T6) to 9.24 mm (T14). Posterior cortex to anterior cortex depth ranged from 25.9 to 32.6 mm. Mean bone mineral density was 1.0665 g/cm 2 (range 1.139-1.016). Force-to-failure demonstrated mean 1171.40 N (+ 115.34)., Conclusion: Our baseline morphometric and compositional data demonstrate that porcine vertebrae can serve as a useful model for comparative studies due to their similar pedicle widths and bone mineral density to the human vertebra. This biomechanical data could provide a baseline comparison for future studies. This study also suggests that the minipig could be a suitable model for comparative studies due to similarities in pedicle width and bone mineral density to the human vertebrae.

Study Design: Prospective, nonrandomized, clinical study., Objective: Epidural steroid injections (ESIs) are an important diagnostic and treatment modality for spine pathology. The success of these injections has been attributed to the anatomic location reached by the injectate. This study evaluates injectate dispersal patterns after cervical interlaminar ESI using magnetic resonance imaging (MRI)., Methods: Patients between the ages of 18 and 85 years with cervical radiculopathy were identified. After obtaining consent for study participation, a gadolinium-enhanced cervical ESI was administered via an interlaminar approach under fluoroscopic guidance. Study participants underwent a cervical spine MRI within 15 minutes of administering the injection. Craniocaudal dispersal and the presence or absence of circumferential dispersal was assessed., Results: The injectate dispersed a mean of 8.11 cm in the cranial direction, 6.63 cm in the caudal direction, and 360° circumferentially. No adverse events related to the ESI were reported., Conclusions: Fluoroscopy-guided cervical interlaminar ESI resulted in nearly uniform circumferential dispersal within the epidural space with multilevel migration in the cranial and caudal directions. MRI is a safe and accurate tool to evaluate spinal injectate dispersal., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Goldstein is an AOSpine member. The other authors have no conflicts of interest to disclose.

Study Design: Longitudinal survey., Objective: It remains important to align competence-based objectives for training as deemed important by clinical fellows to those of their fellowship supervisors and program educators. The primary aim of this study was to determine trainee views on the relative importance of specific procedural training competencies. Secondarily, we aimed to evaluate self-perceived confidence in procedural performance at the commencement and completion of fellowship., Methods: Questionnaires were administered to 68 clinical fellows enrolled in the AOSNA fellowship program during the 2015-2016 academic year. A Likert-type scale was used to quantify trainee perspectives on the relative importance of specific procedural competencies to their training base on an established curriculum including 53 general and 22 focused/advanced procedural competencies. We measured trainee self-perceived confidence in performing procedures at the commencement and completion of their program. Statistical analysis was performed on fellow demographic data and procedural responses., Results: Our initial survey response rate was 82% (56/68) and 69% (47/68) for the follow-up survey. Although most procedural competencies were regarded of high importance, we did identify several procedures of high importance yet low confidence among fellows (ie, upper cervical, thoracic discectomy surgery), which highlights an educational opportunity. Overall procedural confidence increased from an average Likert score of 4.2 (SD = 1.3) on the initial survey to 5.4 (SD = 0.8) by follow-up survey ( P < .0001)., Conclusions: Understanding trainee goals for clinical fellowship remains important. Identification of areas of low procedural confidence and high importance to training experience will better guide fellowship programs and supervisors in the strategic delivery of the educational experience., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Study Design: Retrospective literature review of spine surgical site infection (SSI)., Objective: To perform a review of SSI risk factors and more specifically, categorize them into patient and surgical factors., Methods: A review of published literature on SSI risk factors in adult spine surgery was performed. We included studies that reported risk factors for SSI in adult spinal surgery. Excluded are pediatric patient populations, systematic reviews, and meta-analyses. Overall, we identified 72 cohort studies, 1 controlled-cohort study, 1 matched-cohort study, 1 matched-paired cohort study, 12 case-controlled studies (CCS), 6 case series, and 1 cross-sectional study., Results: Patient-associated risk factors-diabetes mellitus, obesity (body mass index >35 kg/m 2 ), subcutaneous fat thickness, multiple medical comorbidities, current smoker, and malnutrition were associated with SSI. Surgical associated factors-preoperative radiation/postoperative blood transfusion, combined anterior/posterior approach, surgical invasiveness, or levels of instrumentation were associated with increased SSI. There is mixed evidence of age, duration of surgery, surgical team, intraoperative blood loss, dural tear, and urinary tract infection/urinary catheter in association with SSI., Conclusion: SSIs are associated with many risk factors that can be patient or surgically related. Our review was able to identify important modifiable and nonmodifiable risk factors that can be essential in surgical planning and discussion with patients., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose of Review: This is a literature review of the measurement of patient satisfaction in musculoskeletal medicine. Its purpose is to better understand the motivation for such measurements, the potential confounders, and the potential physician behaviors that may modulate such measures., Recent Findings: There have been studies documenting that physician conveyance of empathy, the extent to which patients' expectations for pain control and timeliness of care are met, as well as patient demographics and health status all affect the current measures of patient satisfaction. In the mission to affect patient-centered care are met, musculoskeletal providers will be measured by their patients' satisfaction. There is much yet to be understood regarding patients' expectations of care; the science behind case-mix adjustment in this sphere is in its infancy, but there are some compelling reasons for musculoskeletal providers to attempt to optimize their patients' satisfaction.

There continue to be incremental advances in thoracolumbar spine surgery techniques in attempts to achieve more predictable outcomes, minimize risk of complications, speed recovery, and minimize the costs of these interventions. This paper reviews recent literature with regard to emerging techniques of interest in the surgical treatment of lumbar spinal stenosis, fusion fixation and graft material, degenerative lumbar spondylolisthesis, and thoracolumbar deformity and sacroiliac joint degeneration. There continue to be advances in minimal access options in these areas, although robust outcome data are heterogeneous in its support. The evidence in support of sacroiliac fusion appears to be growing more robust in the properly selected patient., (Copyright © 2016 by the Congress of Neurological Surgeons.)

Patient-reported outcome measures are helping clinicians to use evidence-based medicine in decision making. The use of computer-based questionnaires to gather such data may offer advantages over traditional paper-based methods. These advantages include consistent presentation, prompts for missed questions, reliable scoring, and simple and accurate transfer of information into databases without manual data entry. The authors enrolled 308 patients over a 16-month period from 3 orthopedic clinics: spine, upper extremity, and trauma. Patients were randomized to complete either electronic or paper validated outcome forms during their first visit, and they completed the opposite modality at their second visit, which was approximately 7 weeks later. For patients with upper-extremity injuries, the Penn Shoulder Score (PSS) was used. For patients with lower-extremity injuries, the Foot Function Index (FFI) was used. For patients with lumbar spine symptoms, the Oswestry Disability Index (ODI) was used. All patients also were asked to complete the 36-Item Short Form Health Survey (SF-36) Health Status Survey, version 1. The authors assessed patient satisfaction with each survey modality and determined potential advantages and disadvantages for each. No statistically significant differences were found between the paper and electronic versions for patient-reported outcome data. However, patients strongly preferred the electronic surveys. Additionally, the paper forms had significantly more missed questions for the FFI (P<.0001), ODI (P<.0001), and PSS (P=.008), and patents were significantly less likely to complete these forms (P<.0001). Future research should focus on limiting the burden on responders, individualizing forms and questions as much as possible, and offering alternative environments for completion (home or mobile platforms)., (Copyright 2016, SLACK Incorporated.)

Demographic trends make it incumbent on orthopaedic spine surgeons to recognize the special challenges involved in caring for older patients with spine pathology. Unique pathologies, such as osteoporosis and degenerative deformities, must be recognized and treated. Recent treatment options and recommendations for the medical optimization of bone health include vitamin D and calcium supplementation, diphosphonates, and teriparatide. Optimizing spinal fixation in elderly patients who have osteoporosis is critical; cement augmentation of pedicle screws is promising. In the management of geriatric odontoid fractures, nonsurgical support with a collar may be considered for low-demand patients, whereas surgical fixation is favored for high-demand patients. Management of degenerative deformity must address sagittal plane balance, which includes consideration of pelvic incidence. Various osteotomies may prove helpful in this setting.

Demographic trends make it incumbent on orthopaedic spine surgeons to recognize the special challenges involved in caring for older patients with spine pathology. Unique pathologies, such as osteoporosis and degenerative deformities, must be recognized and dealt with. Recent treatment options and recommendations for the medical optimization of bone health include vitamin D and calcium supplementation, diphosphonates, and teriparatide. Optimizing spinal fixation in elderly patients with osteoporosis is critical; cement augmentation of pedicle screws is promising. In the management of geriatric odontoid fractures, nonsurgical support with a collar may be considered for the low-demand patient, whereas surgical fixation is favored for high-demand patients. Management of degenerative deformity must address sagittal plane balance, including consideration of pelvic incidence. Various osteotomies may prove helpful in this setting., (Copyright 2015 by the American Academy of Orthopaedic Surgeons.)

Osteoporosis, the most common form of metabolic bone disease, leads to alterations in bone structure and density that have been shown to compromise the strength of spinal instrumentation. In addition, osteoporosis may contribute to high rates of fracture and instrumentation failure after long posterior spinal fusions, resulting in proximal junctional kyphosis and recurrent spinal deformity. As increasing numbers of elderly patients present for surgical intervention for degenerative and traumatic spinal pathologies, current and future generations of spine surgeons will increasingly be faced with the challenge of obtaining adequate fixation in osteoporotic bone. The purpose of this review is to familiarize the reader with the impact of osteoporosis on spinal instrumentation, the broad variety of techniques that have been developed for addressing these issues, and the biomechanical and clinical evidence in support of the use of these techniques.

Vertebral compression fractures (VCFs) are the most common type of fracture secondary to osteoporosis. These fractures are associated with significant rates of morbidity and mortality and annual direct medical expenditures of more than $1 billion in the United States. Although many patients will respond favorably to nonsurgical care of their VCF, contemporary natural history data suggest that more than 40% of patients may fail to achieve significant pain relief within 12 months of symptom onset. As a result, percutaneous vertebral augmentation is often used to hasten symptom resolution and return of function. However, controversy regarding the role of kyphoplasty and vertebroplasty in the treatment of symptomatic VCFs exists. The purposes of this review are (1) to outline the epidemiology of VCFs as well as the physical morbidity and economic impact of these injuries, (2) to familiarize the reader with the best available evidence surrounding the operative and nonoperative treatment of VCFs, and (3) to examine the literature pertaining to the cost-effectiveness of surgical management of VCFs with the overarching goal of helping physicians make informed decisions regarding symptomatic VCF treatment.

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/objective: Whole organ in vitro intervertebral disc models have been associated with poor maintenance of cell viability. No previous studies have used a rotating wall vessel bioreactor for intervertebral disc explants culture. The purpose of this study was to develop and validate an in vitro model for the assessment of biological and biomechanical measures of intervertebral disc health and disease., Methods: To this end, endplate-intervertebral disc-endplate whole organ explants were harvested from the tails of rats. For the injured group, the annulus fibrosus was penetrated with a 20G needle to the nucleus pulposus and aspirated. Explants were cultured in a rotating wall vessel bioreactor for 14 days., Results: Cell viability and histologic assessments were performed at Day 0, Day 1, Day 7, and Day 14. Compressive mechanical properties of the intervertebral disc were assessed at Day 0 and Day 14. In the annulus fibrosus and nucleus pulposus cells, the uninjured group maintained high viability through 14 days of culture, whereas cell viability in annulus fibrosus and nucleus pulposus of the injured intervertebral discs was markedly lower at Day 7 and Day 14. Histologically, the uninjured intervertebral discs maintained cell viability and tissue morphology and architecture through 14 days, whereas the injured intervertebral discs showed areas of cell death, loss of extracellular matrix integrity, and architecture by Day 14. Stiffness values for uninjured intervertebral discs were similar at Day 0 and Day 14, whereas the stiffness for the injured intervertebral discs was approximately 2.5 times greater at Day 14., Conclusion: These results suggest that whole organ intervertebral discs explants can be successfully cultured in a rotating wall vessel bioreactor to maintain cell viability and tissue architecture in both annulus fibrosus and nucleus pulposus for at least 14 days. In addition, the injury used produced pathologic changes consistent with those seen in degenerative intervertebral disc disease in humans. This model will permit further study into potential future treatments and other mechanisms of addressing intervertebral disc disease.

A validated, using in vitro biomechanical testing, finite element model was used to evaluate the affects of (1) cement augmentation and (2) an intact posterior cortex in osteoporotic bone. The presence of augmentation and/or a posterior cortical cortex increased the stabilization of the pedicle screw 2-5 fold. Placement of cement influenced failure load and toggle; with distal placement having the largest increase in failure load and decrease in cephalad-caudad toggle. The presence of posterior cortex caused a decrease in the amount of toggle, a proximal shift of the center of rotation and an increase in the maximum failure force.

Transient quadriplegia is a rare injury that can change the course of an athlete's career if misdiagnosed or managed inappropriately. The clinician should be well versed in the return-to-play criteria for this type of injury. Unfortunately, when an unknown preexisting syrinx is present in the athlete, there is less guidance on their ability to return to play. This case report and review of the current literature illustrates a National Collegiate Athletic Association (NCAA) Division I football player who suffered a transient quadriplegic event during a kickoff return that subsequently was found to have an incidental cervical syrinx on magnetic resonance imaging. The player was able to have a full neurologic recovery, but ultimately he was withheld from football.

Study Design Biomechanical study of pedicle screw fixation in osteoporotic bone. Objective To investigate whether it is better to tap or not tap osteoporotic bone prior to placing a cement-augmented pedicle screw. Methods Initially, we evaluated load to failure of screws placed in cancellous bone blocks with or without prior tapping as well as after varying the depths of tapping prior to screw insertion. Then we evaluated load to failure of screws placed in bone block models with a straight-ahead screw trajectory as well as with screws having a 23-degree cephalad trajectory (toward the end plate). These techniques were tested with nonaugmented (NA) screws as well as with bioactive cement (BioC) augmentation prior to screw insertion. Results In the NA group, pretapping decreased fixation strength in a dose-dependent fashion. In the BioC group, the tapped screws had significantly greater loads to failure (p < 0.01). Comparing only the screw orientation, the screws oriented at 23 degrees cephalad had a significantly higher failure force than their respective counterparts at 0 degrees (p < 0.01). Conclusions Standard pedicle screw fixation is often inadequate in the osteoporotic spine, but this study suggests tapping prior to cement augmentation will substantially improve fixation when compared with not tapping. Angulating screws more cephalad also seems to enhance aging spine fixation.

We hypothesised that cells obtained via a Reamer-Irrigator-Aspirator (RIA) system retain substantial osteogenic potential and are at least equivalent to graft harvested from the iliac crest. Graft was harvested using the RIA in 25 patients (mean age 37.6 years (18 to 68)) and from the iliac crest in 21 patients (mean age 44.6 years (24 to 78)), after which ≥ 1 g of bony particulate graft material was processed from each. Initial cell viability was assessed using Trypan blue exclusion, and initial fluorescence-activated cell sorting (FACS) analysis for cell lineage was performed. After culturing the cells, repeat FACS analysis for cell lineage was performed and enzyme-linked immunosorbent assay (ELISA) for osteocalcin, and Alizarin red staining to determine osteogenic potential. Cells obtained via RIA or from the iliac crest were viable and matured into mesenchymal stem cells, as shown by staining for the specific mesenchymal antigens CD90 and CD105. For samples from both RIA and the iliac crest there was a statistically significant increase in bone production (both p < 0.001), as demonstrated by osteocalcin production after induction. Medullary autograft cells harvested using RIA are viable and osteogenic. Cell viability and osteogenic potential were similar between bone grafts obtained from both the RIA system and the iliac crest.

Study Design: A retrospective analysis of the morbidity and mortality data collected by the SRS in 2009 with comparison to previous years., Objectives: Objective of this study was to assess the new format of morbidity and mortality data collection by the SRS in 2009 and evaluate the data collected with comparison to previous years., Summary of Background Data: 2009 morbidity and mortality reporting format was dramatically changed from previous years. This was done in an attempt to simplify the reporting process and to narrow the reporting to only three sentinel events: death, blindness, and neurologic injury. Only deformity cases including scoliosis, kyphosis, and Grade III or greater spondylolisthesis were included., Methods: Results were obtained from the SRS M & M reporting summary for 2009. These included detailed analysis for complications including death, blindness, and neurologic injury. These were compared to similar statistics obtained from the years dating back to 2001. Blindness has not previously been reported., Results: 80.1% of SRS members submitted 35,267 deformity cases. Both the percentage of members submitting data and the number of deformity cases far exceeded any previous year total. 57.6% of cases involved scoliosis, 10.5% kyphosis, and 31.9% spondylolisthesis. Neurologic complications were lower in each major category (scoliosis, kyphosis, and spondylolisthesis) compared to previous years. The death rate was similar to prior reporting 0.12%. Three cases of blindness were reported, two occurred in AIS. All three resolved., Conclusions: The altered format and requirement for all members to participate has dramatically increased the total number of deformity cases reported and percent of membership responding. Neurologic injury rates are decreased from previous years. Three cases of blindness occurred, all of which resolved. Further collection of data is needed to elucidate mechanism and prevention., (Copyright © 2013 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Background: The requirement of obtaining informed consent before medical procedures is well established. With patients having greater access to information through information technology and owing to other factors, disclosure that goes beyond the traditional elements of the risks, benefits, and alternatives to an intervention is demanded from physicians., Questions/purposes: We asked if modern informed consent doctrine encompasses such physician-specific variables like professional experience, health, disability, training, qualifications, disciplinary history, FDA-regulatory status pertaining to a medical device, physician research and financial interests, and statistics related to medical outcomes., Methods: We searched two major legal databases and identified court opinions and legal reviews that have examined the scope of physician disclosure while obtaining informed consent. From this information, we summarized the prevailing state of informed consent law., Results: Despite the expansion of information available to patients, courts have been hesitant to expand the informed consent doctrine to encompass physician-specific variables. Exceptions involve cases in which such variables directly impacted medical care and the patient could demonstrate their relevance in the informed consent process., Conclusions: Judicial decisions have subtly expanded the doctrine of informed consent beyond its traditional limits, at least in some cases. As informed consent law continues to develop, physicians should ask if information would be material to a reasonable patient while making medical decisions; if so, such information should be disclosed.

Study Design: Biomechanical analysis of bioactive cements augmenting pedicle screw resistance to loosening in osteoporotic synthetic bone., Objective: To simulate in vivo loading-loosening of pedicle screws in osteoporotic vertebrae; and to compare biomechanical efficacy of the following bioactive cements: calcium phosphate (CP), calcium sulfate (CS), and proprietary mixture (M)., Summary of Background Data: Pedicle screw instrumentation in osteoporotic spines is limited by poor bone-screw interface strength, resulting in screw loosening fixation failure. Previous in vivo studies evaluated augmented pedicle screw resistance to pure pullout, not simulating in vivo loading/failure., Methods: A pedicle screw-instrumented osteoporotic thoracic vertebra subjected to combined pullout, transverse, moment loading was simulated. Unconstrained 3-dimensional screw motion relative to vertebra was optically measured during quasi-static, and dynamic loading., Results: Augmented groups (CP, CS, M) produced (P < 8.0E-07) higher quasi-static failure initiation force (61.2,45.6, 40.3 N) than those by the nonaugmented group (21.0 N), with no significant difference in small screw displacement up to these loads. Nonaugmented screw motion after failure initiation was primarily rotation (toggle-migration) with minimal pullout until the screw tip contacted the superior endplate, followed by more prominent screw pullout. Augmented screw motion (with cement remaining intact on screw) was similar, but with eventual bone fracture anterior to the pedicle region. Dynamic loading produced similar failure initiation force and screw motion., Conclusion: We believe our test protocol produced screw loosening failure similar to that observed clinically, and that it has the ability to detect differences in failure initiation force and failure modes to compare short-term efficacy of screw augmentation techniques. All cements improved screw resistance to failure. The CP > CS > M failure initiation force (P < 0.006) was because of differences in cement distribution. Animal studies may be required to characterize the remodeling activity of bioactive cements and their longer term efficacies.

Background: Unintended durotomy is a common complication of spinal surgery. However, the incidences reported in the literature vary widely and are based primarily on relatively small case numbers from a single surgeon or institution., Objective: To provide spine surgeons with a reliable incidence of unintended durotomy in spinal surgery and to assess various factors that may influence the risk of durotomy., Methods: We assessed 108,478 surgical cases prospectively submitted by members of the Scoliosis Research Society to a deidentified database from 2004 to 2007., Results: Unintended durotomy occurred in 1.6% (1745 of 108 478) of all cases. The incidence of unintended durotomy ranged from 1.1% to 1.9% on the basis of preoperative diagnosis, with the highest incidence among patients treated for kyphosis (1.9%) or spondylolisthesis (1.9%) and the lowest incidence among patients treated for scoliosis (1.1%). The most common indication for spine surgery was degenerative spinal disorder, and among these patients, there was a lower incidence of durotomy for cervical (1.0%) vs thoracic (2.2%; P = .01) or lumbar (2.1%, P < .001) cases. Scoliosis procedures were further characterized by etiology, with the highest incidence of durotomy in the degenerative subgroup (2.2% vs 1.1%; P < .001). Durotomy was more common in revision compared with primary surgery (2.2% vs 1.5%; P < .001) and was significantly more common among elderly (> 80 years of age) patients (2.2% vs 1.6%; P = .006). There was a significant association between unintended durotomy and development of a new neurological deficit (P < .001)., Conclusion: Unintended durotomy occurred in at least 1.6% of spinal surgeries, even among experienced surgeons. Our data provide general benchmarks of durotomy rates and serve as a basis for ongoing efforts to improve safety of care.

Object: This is a retrospective review of 10,242 adults with degenerative spondylolisthesis (DS) and isthmic spondylolisthesis (IS) from the morbidity and mortality (M&M) index of the Scoliosis Research Society (SRS). This database was reviewed to assess complication incidence, and to identify factors that were associated with increased complication rates., Methods: The SRS M&M database was queried to identify cases of DS and IS treated between 2004 and 2007. Complications were identified and analyzed based on age, surgical approach, spondylolisthesis type/grade, and history of previous surgery. Age was stratified into 2 categories: > 65 years and ≤ 65 years. Surgical approach was stratified into the following categories: decompression without fusion, anterior, anterior/posterior, posterior without instrumentation, posterior with instrumentation, and interbody fusion. Spondylolisthesis grades were divided into low-grade (Meyerding I and II) versus high-grade (Meyerding III, IV, and V) groups. Both univariate and multivariate analyses were performed., Results: In the 10,242 cases of DS and IS reported, there were 945 complications (9.2%) in 813 patients (7.9%). The most common complications were dural tears, wound infections, implant complications, and neurological complications (range 0.7%-2.1%). The mortality rate was 0.1%. Diagnosis of DS had a significantly higher complication rate (8.5%) when compared with IS (6.6%; p = 0.002). High-grade spondylolisthesis correlated strongly with a higher complication rate (22.9% vs 8.3%, p < 0.0001). Age > 65 years was associated with a significantly higher complication rate (p = 0.02). History of previous surgery and surgical approach were not significantly associated with higher complication rates. On multivariate analysis, only the grade of spondylolisthesis (low vs high) was in the final best-fit model of factors associated with the occurrence of complications (p < 0.0001)., Conclusions: The rate of total complications for treatment of DS and IS in this series was 9.2%. The total percentage of patients with complications was 7.9%. On univariate analysis, the complication rate was significantly higher in patients with high-grade spondylolisthesis, a diagnosis of DS, and in older patients. Surgical approach and history of previous surgery were not significantly correlated with increased complication rates. On multivariate analysis, only the grade of spondylolisthesis was significantly associated with the occurrence of complications.

Object: The purpose of this study was to evaluate the prospectively collected Scoliosis Research Society (SRS) database to assess the incidences of morbidity and mortality (M&M) in the operative treatment of degenerative lumbar stenosis, one of the most common procedures performed by spine surgeons., Methods: All patients who underwent surgical treatment for degenerative lumbar stenosis between 2004 and 2007 were identified from the SRS M&M database. Inclusion criteria for analysis included an age >or= 21 years and no history of lumbar surgery. Patients were treated with either decompression alone or decompression with concomitant fusion. Statistical comparisons were performed using a 2-sided Fisher exact test., Results: Of the 10,329 patients who met the inclusion criteria, 6609 (64%) were treated with decompression alone, and 3720 (36%) were treated with decompression and fusion. Among those who underwent fusion, instrumentation was placed in 3377 (91%). The overall mean patient age was 63 +/- 13 years (range 21-96 years). Seven hundred nineteen complications (7.0%), including 13 deaths (0.1%), were identified. New neurological deficits were reported in 0.6% of patients. Deaths were related to cardiac (4 cases), respiratory (5 cases), pulmonary embolus (2 cases), and sepsis (1 case) etiologies, and a perforated gastric ulcer (1 case). Complication rates did not differ based on patient age or whether fusion was performed. Minimally invasive procedures were associated with fewer complications and fewer new neurological deficits (p = 0.01 and 0.03, respectively)., Conclusions: The results from this analysis of the SRS M&M database provide surgeons with useful information for preoperative counseling of patients contemplating surgical intervention for symptomatic degenerative lumbar stenosis.

Study Design: We retrieved a functioning ProDisc-L total disc replacement and associated tissues at 16 months of service life., Objective: To analyze a previously unreported mode of implant malpositioning, wear mechanisms, and polyethylene locking mechanism, and to study retrieved periprosthetic tissues., Summary of Background Data: The clinical performance of polyethylene in the context of total disc replacements remains poorly understood. In the ProDisc-L, the polyethylene core is fixed to the inferior metal endplate through a mechanical interference locking mechanism similar to those used in tibial total knee components. This case represents the third report of an explanted ProDisc-L prosthesis, and the first reported case of posterior malpositioning with this device., Methods: The implant was removed via a transperitoneal approach. Its polyethylene core was evaluated for burnishing, fracture, third-body abrasion, and permanent deformation. An identical, never-implanted set of polyethylene and endplate components served as controls for the microscopic evaluation of wear. Two tissue samples were collected from a region adjacent to the failed implant to evaluate tissue morphology and inflammation. Hematoxylin and eosin-stained tissue sections were also evaluated for the presence of polyethylene debris by polarized light microscopy., Results: The implant was removed without serious incident, although there were incidental venotomies. The patient went on to solid arthrodesis. We found minimal wear, oxidation, and periprosthetic tissue reaction, as might be expected given the short-term duration of implantation and its reason for revision. No evidence was found of malfunction or improper deployment of the locking mechanism. Burnishing seemed to be the result of short-term impingement. Some areas of the tissue matrix showed evidence of early cell degeneration, and some of these areas contained polyethylene particles identified by polarized light microscopy., Conclusions: A larger series of implant retrievals will be needed to investigate possible wear and the biologic response to increased particle generation.

Study Design: An anatomic study of 100 patients comparing the pedicle isthmic width of the lower thoracic spine and the upper lumbar spine using magnetic resonance imaging., Objectives: To compare the lower thoracic pedicles and upper lumbar pedicles in nondeformity patients as a surrogate measure of safety of pedicle screw use., Summary of Background Data: Pedicle isthmic width is the significant limiting factor in the safety and proper placement of transpedicular screws. The presumption in the past has been that the lumbar pedicles are larger than the thoracic pedicles. Few publications in the English-language literature specifically evaluate the association between the pedicle isthmic widths of the lower thoracic and upper lumbar., Methods: The study evaluates 100 patients, without coronal spinal deformities. MRIs were obtained of the pedicles from T10 to L2 and subsequently measured using the axial T2-weighted views. Lower thoracic and upper lumbar pedicle isthmus, the narrowest section of pedicle, was investigated and compared. The "medial pedicle to medial rib corridor" at T10-T12 was defined and measured as part of the methodology of the study. Statistical analysis included one-way analysis of variance with post hoc least significant difference pairwise comparisons., Results: The smallest pedicle isthmic width was at L1 (mean +/- SD, 6.0 +/- 1.6 mm), while T12 (mean +/- SD, 7.6 +/- 1.5 mm) had the largest pedicle width. Although smaller in diameter than T12, both T10 (mean +/- SD, 6.2 +/- 1.2 mm) and T11 (mean +/- SD, 7.5 +/- 1.6 mm) had larger pedicle width than L1 (P < 0.01). Pedicle widths were larger in males compared with females (P < 0.05)., Conclusions: The results show that the lower thoracic pedicles are larger than the upper lumbar pedicles. This may make it safer to place screws in the lower thoracic spine than in the upper lumbar spine. Upper lumbar may be so small (<5 mm) to preclude safe conventional screw placement.

Objective: The objective of this study is to evaluate the effectiveness of a specific methodology for plain radiographic assessment of lumbar pedicle screw position., Purpose: To evaluate the effectiveness of using orthogonal plain radiographs and a systematic method of interpretation, developed by the senior author, in assessing the placement of lumbar and lumbosacral pedicle screws., Study Design: This was an adult cadaver study of the accuracy of using plain radiographs or computed tomography to assess pedicle screw position. Plain radiographs were performed and compared with computed tomography (CT) scans. Gross anatomic dissections were performed to directly confirm screw position. Variables, including screw material, radiographic view, and screw dimensions, were assessed for their effect on the ability of physicians to determine pedicle screw position. Multiple readers were included in the study, including 1 spine Fellow, 3 experienced orthopedic spine surgeons, and 1 neuroradiologist., Methods: Five adult cadaveric spines were instrumented with titanium pedicle screws from L1 to S1. Screws were placed outside the confines of the pedicle in all 4 quadrants or within the pedicle using a Latin-Square design. Each cadaver was imaged with orthogonal radiographs and high-resolution CT scans. The spines were then reimaged after the instrumentation was replaced with stainless steel screws placed in the identical position. Finally, each spine was dissected to assess the exact position of the screws. Images were read in a blinded fashion by 1 spine fellow, 2 staff surgeons, and a staff radiologist. The results were compared with the known screw positions at dissection., Results: In total, 120 pedicle screws were placed, 44 (38%) outside the confines of the pedicle. Sensitivity, defined as the percent of the misplaced screws that were correctly identified, was similar across the 3 diagnostic tests, but markedly improved when all CT formats were considered together. Similarly, specificity, defined as the percent of screws correctly read as being placed within the pedicle, was independent of radiographic examination. Sensitivity of the radiographic technique was 70.1% and specificity was 83.0%, whereas sensitivity for CT scans was 84.7% and specificity was 89.7%. There was an observed association with anatomic level, with a consistently less accuracy in detecting screw position at L1 with plain x-ray (P=0.001). Additionally, correct position of stainless steel screws was more difficult to detect as compared with titanium (P=0.033) using either x-rays or CT. Other variables examined, such as screw length and screw diameter, did not have an effect on the ability to read the positioning., Conclusions: CT scans, often considered the "gold standard" for clinical assessment of pedicle screw placement, have limitations when validated with gross anatomical dissection. The described systematic method for evaluating pedicle screw placement using orthogonal plain radiographs attained accuracy comparable to high-resolution CT scans.

Paget's disease of bone, although common in the United States, is relatively rare in patients younger than 40 years. In a large archival series, 10% of patients with Paget's disease of bone were younger than 40 years. Pain followed by pathologic fracture was the most common presenting complaint in this group of patients. There was no gender difference comparing the younger group with the older group of patients. Of the 521 patients in this series, only 10 were African-American; the others were Caucasians. Seven African-American patients were in the group of patients who were younger than 40 years. Appendicular and monostotic bone involvement was more frequent in the younger age group although these differences were not statistically significant. The incidence of malignant transformation in pagetic bone was high (30.3%), and is a reflection of the high volume of uncommon tumor referrals to our consultation service. However, there were no cases of associated malignancies in the group of patients younger than 40 years.

This is an in vitro study of the mechanical effects of varying hook attachment patterns in long segment kyphotic deformity. In such cases, the optimal implant bulk, fatigue life, and construct rigidity to reliably achieve fusion are still unquantified. Rod strains were measured for multiple laminar hook patterns in a synthetic thoracic spine test bed. Stresses were calculated from strain data. The model displayed similar flexion bending stiffness to the thoracic spine. None of the hook patterns significantly changed overall construct stiffness. Greatest rod strains were seen when utilizing away-facing apical hooks. This model was too stiff to detect differences in construct stiffness. Nonetheless, rod stress analysis showed that for multisegment thoracic constructs, particularly with fixed kyphosis, minimizing apical hooks will minimize rod strain. If periapical hooks are necessary, orienting the hooks toward the apex will minimize rod strain.