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Background: Cervical laminoplasty and laminectomy and fusion (LF) are posterior-based surgical techniques for the surgical treatment of cervical spondylotic myelopathy (CSM). Interestingly, the comparative amount of spinal cord drift obtained from these procedures has not been extensively described. The purpose of this study is to compare spinal cord drift between cervical laminoplasty and LF in patients with CSM., Methods: The laminoplasty group consisted of 22 patients, and the LF group consisted of 44 patients. Preoperative and postoperative alignment was measured using the Cobb angle (C2-C7). Spinal cord position was measured on axial T2-magnetic resonance imaging of the cervical spine preoperatively and postoperatively. Spinal cord drift was quantified by subtracting preoperative values from postoperative values. Functional improvement was assessed using the modified Japanese Orthopaedic Association (mJOA) score., Results: Mean spinal cord drift was higher following LF compared to laminoplasty (2.70 vs 1.71 mm, P < .01). Using logistic regression analysis, there was no correlation between sagittal alignment and spinal cord drift. Both groups showed an improvement in mJOA scores postoperatively compared to their preoperative values (laminoplasty, +2.0, P = .012; LF, +2.4, P < .01). However, there was no difference in mJOA score improvement postoperatively between both groups ( P = .482)., Conclusions: This study demonstrates that patients who had LF for CSM achieved more spinal cord drift postoperatively compared to those who had laminoplasty. However, the increased drift did not translate into superior functional outcome as measured by the mJOA score., Level of Evidence: 3., Clinical Relevance: Spinal cord drift following LF may differ from laminoplasty in patients undergoing surgery for CSM. This finding should be considered when assessing CSM patients for surgical intervention., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2021 ISASS.)

Purpose: To date, there are conflicting reports with no consensus on the influence of bisphosphonates on lumbar fusion. The goal of this study was to compare the radiographic and functional outcomes of patients that had lumbar fusion with and without bisphosphonates., Methods: A systematic search of multiple medical reference databases was conducted for studies comparing bisphosphonate use to controls following spinal fusion. Meta-analysis was performed using the random-effects model for heterogeneity. Radiographic outcome measures included fusion rates and risk of screw loosening, cage subsidence and vertebral fracture. Functional outcomes measures included Oswestry Disability Index and visual analog scale score for back and leg pain., Results: Bisphosphonate use was statistically suggestive of a higher fusion rate compared to controls (OR 2.2, 95% CI 0.87-5.56, p = 0.09). There was no difference in screw loosening rates between the bisphosphonate group and controls (OR 0.45, 95% CI 0.14-1.48, p = 0.19). However, bisphosphonate use was associated with decreased odds of cage subsidence and vertebral fractures compared to controls (cage subsidence: OR 0.29, 95% CI 0.11-0.75, p = 0.01; vertebral fracture: OR 0.18, 95% CI 0.07-0.48, p = 0.0007)., Conclusion: Bisphosphonate use does not appear to impair successful lumbar fusion compared to controls. Additionally, bisphosphonate use was associated with decreased odds of cage subsidence and vertebral fractures compared to controls that had lumbar fusion. These slides can be retrieved under Electronic Supplementary Material.

Background: Pedicle screw malposition may result in neurological complications following posterolateral lumbar fusions (PLF). While computer-assisted navigation (NAV) and intraoperative neuromonitoring (ION) have been shown to improve safety in deformity surgeries, their use in routine PLFs remain controversial. This study assesses the risk of complications and reoperation for pedicle screw revision following PLF with and without ION and/or NAV surgery., Methods: Retrospective analyses were performed using the Truven Health MarketScan ® databases to identify patients that had primary PLF with and without NAV and/or ION for degenerative lumbar disorders from years 2007-2015. Patients undergoing concomitant interbody fusions, spinal deformity surgery or fusion to the thoracic spine were excluded. Complications and reoperation for pedicle screw revision within 90 days of surgery were assessed., Results: During the study period, 67,264 patients underwent PLFs. NAV only was used in 3.5% of patients, ION only in 17.9% and both NAV and ION in 0.8% of patients. In univariate analyses, there was a difference in the risk of neurological injuries among groups (NAV only: 1.4%, ION only: 0.8%, NAV and ION: 0.5%, No NAV or ION: 0.6%, P<0.001). In multivariable models, the use of NAV was associated with a higher risk of neurological complications when compared to ION only or no ION or NAV [NAV vs. ION only: odds ratio (OR) and 95% confidence interval (CI) =2.1 (1.4, 3.2), P=0.002; NAV vs. no ION or NAV: OR and 95% CI =2.5 (1.7, 3.5), P<0.001]. There was no difference in reoperation rates among the groups (P=0.135)., Conclusions: Although the overall risk of neurological complications following PLFs is low, the use of NAV only was associated with an increased risk of neurological complications. No differences were observed in the rates of pedicle screw revision among groups., Competing Interests: Conflicts of Interest: I Cheng—Nuvasive, Royalties, consulting; Globus Medical, Royalties; Spine Wave, Royalties; SpineCraft, Royalties; Cytonics, Stock; Spine Innovations, Stock; SpinalCyte, Stock. The other authors have no conflicts of interest to declare., (2019 Journal of Spine Surgery. All rights reserved.)

Background Context: It is recognized that radiological parameters of type 2 dens fractures, including displacement and angulation, are predictive of treatment outcomes and are used to guide surgical decision-making. The reproducibility of such measurements, therefore, is of critical importance. Past literature has shown poor interobserver reliability for both displacement and angulation measurements of type 2 dens fractures. Since such studies however, various advancements of radiological review systems and measurement tools have evolved to potentially improve such measurements., Purpose: To re-examine the inter-rater reliability of measuring displacement and angulation of type 2 dens fractures using modern radiological review systems. Besides quantitative measurements, the reliability of raters in identifying diagnostic classifications based on translational and angulational displacement was also examined., Study Design: Radiographic measurement reliability and agreement study., Patient Sample: Thirty-seven patients seen at a single institution between 2002 and 2017 with primary diagnosis of acute type 2 dens fracture with complete computed tomography (CT) imaging., Outcome Measures: Radiological measurements included displacement and angulation. Diagnostic classifications based on consensus-based clinical cutoff points were also recorded., Methods: Measurements were performed by five surgeons with varying years of experience in spine surgery using the hospital's electronic medical record radiological measuring tools. The radiological measurements included displacement and angulation. Diagnostic classifications based on consensus-based clinical cutoff points were also recorded. Each rater received a graphic demonstration of the measurement methods, but had the autonomy to select a best cut from the sagittal CT to measure. All raters were blinded to patient information., Results: Measurements for displacement and angulation among the five raters demonstrated "excellent" reliability. Intra-rater reliability was also "excellent" in measuring displacement and angulation. The reliability of diagnostic classification of displacement (above vs. below 5 mm), was found to be "very good" among the raters. The reliability of diagnostic classification of angulation (above vs. below 11°) demonstrated "good" reliability., Conclusions: Advancement of radiological review systems, including review tools and embedded image processing software, has facilitated more reliable measurements for type 2 odontoid fractures., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: To compare perioperative and radiographic outcomes following lateral lumbar interbody fusions in two cohorts of patients who either underwent single position or dual position surgery., Methods: Patients over the age of 18 with degenerative lumbar pathology who underwent a lumbar interbody fusion via lateral access from 2012-2015 from a single surgeon met inclusion criteria. Patients who underwent combined procedures, had a history of retroperitoneal surgery, or had inadequate preoperative imaging were excluded. Patients who remained in the lateral decubitus position for pedicle screw fixation [single-position (SP)] were compared to those turned prone [dual-position (DP)]. Demographics, surgical details, and perioperative outcomes were compared between groups., Results: A total of 42 SP and 24 DP patients were analyzed. The DP group had a 44.4-minute longer operating room time compared to the SP group (P<0.001) after adjusting for the number of levels operated (P<0.001) and unilateral versus bilateral screw placement (P=0.048). Otherwise, no differences were observed in peri-operative outcomes. Lordosis was not different between groups pre-operatively (P>0.999) or post-operatively (P=0.479), and neither was the pre- to post-operative change (P=0.283)., Conclusions: Lateral pedicle screw fixation following lateral interbody fusion decreases operating room time without compromising post-operative lordosis, complication rates, or perioperative outcomes., Competing Interests: Conflicts of Interest: Cheng—Nuvasive, Royalties, consulting; Globus Medical, Royalties; Stryker Spine, Consulting; Spine Wave, Royalties; SpineCraft, Consulting; Cytonics, Stock; Spine Innovations, Stock; SpinalCyte, Stock. The other authors have no conflicts of interest to declare.

Study Design: Systematic review and meta-analysis., Objective: To compare the efficacy of the use of either bisphosphonates or teriparatide on radiographic and functional outcomes of patients that had thoracolumbar spinal fusion., Summary of Background Data: Controversy exists as to whether bisphosphonates interfere with successful spinal arthrodesis. An alternative osteoporosis medication is teriparatide, a synthetic parathyroid hormone that has an anabolic effect on osteoblast function. To date, there is limited comparative data on the influence of bisphosphonates or teriparatide on spinal fusion., Methods: A systematic search of medical reference databases was conducted for comparative studies on bisphosphonate or teriparatide use after thoracolumbar spinal fusion. Meta-analysis was performed using the random-effects model for heterogeneity. Radiographic outcomes assessed include fusion rates, risk of screw loosening, cage subsidence, and vertebral fracture., Results: No statistically significant differences were noted between bisphosphonates and control groups regarding fusion rate and risk of screw loosening (fusion: odds ratio [OR] = 2.2, 95% confidence interval [CI]: 0.87-5.56, P = 0.09; loosening: OR = 0.45, 95% CI: 0.14-1.48, P = 0.19). Teriparatide use was associated with higher fusion rates than bisphosphonates (OR = 2.3, 95% CI: 1.55-3.42, P < 0.0001). However, no statistically significant difference was noted between teriparatide and bisphosphonates regarding risk of screw loosening (OR = 0.37, 95% CI: 0.12-1.18, P = 0.09). Lastly, bisphosphonate use was associated with decreased odds of cage subsidence and vertebral fractures compared to controls (subsidence: OR = 0.29, 95% CI 0.11-0.75, P = 0.01; fracture: OR = 0.18, 95% CI 0.07-0.48, P = 0.0007)., Conclusion: Bisphosphonates do not appear to impair successful spinal fusion compared to controls although teriparatide use is associated with higher fusion rates than bisphosphonates. In addition, bisphosphonate use is associated with decreased odds of cage subsidence and vertebral fractures compared to controls that had spinal fusion., Level of Evidence: 3.

Background: Intraoperative neuromonitoring (ION), such as motor-evoked potential (MEP), somatosensory evoked potentials (SSEP), and electromyography (EMG), is used to detect impending neurological injuries during spinal surgery. To date, little is known about the trends in the use of ION for scoliosis surgery in the United States., Methods: A retrospective review was performed using the PearlDiver Database to identify patients that had scoliosis surgery with and without ION from years 2005 to 2011. Demographic information (such as age, gender, region within the United States) and clinical information (such as type of ION and rates of neurological injury) were assessed., Results: There were 3618 patients who had scoliosis surgery during the study period. Intraoperative neuromonitoring was used in 1361 (37.6%) of these cases. The number of cases in which ION was used increased from 27% in 2005 to 46.9% in 2011 ( P < .0001). Multimodal ION was used more commonly than unimodal ION (64.6% versus 35.4%). The most commonly used modality was combined SSEP and EMG, while the least used modality was MEP only. Neurological injuries occurred in 1.8 and 2.0% of patients that had surgery with and without ION, respectively ( P = .561). Intraoperative neuromonitoring was used most commonly in patients <65 years of age and in the Northeastern part of the United States (age P = .006, region P < .0001)., Conclusions: The use of ION for scoliosis surgery gradually increased annually from 2005 to 2011. Age and regional differences were noted with neuromonitoring being most commonly used for scoliosis surgery in nonelderly patients and in the Northeastern part of the United States. No differences were noted in the risk of neurological injury in patients that had surgery with and without ION. Although the findings from this study may seem to suggest that ION may not influence the risk of neurologic injury, this result must be interpreted with caution as inherently riskier surgeries may utilize ION more, leading to an actual reduction in injuries more dramatic than observed in this study., Competing Interests: Disclosures and COI: No funds were received in support of this work. No relevant financial disclosures are associated with this work.

Consensus is lacking regarding optimal surgical treatment of recurrent lumbar disk herniation. A systematic search of multiple databases was conducted for studies evaluating outcomes after treatment for recurrent lumbar disk herniation. Treatment options included decompression surgeries and fusion surgeries. Although fusion surgeries eliminated re-recurrence of disk herniation, this coincided with higher incidences of complications and reoperation. Decompression surgeries and fusion surgeries both resulted in improvements in Japanese Orthopaedic Association, Oswestry Disability Index, and visual analog scale back and leg scores postoperatively (P<.05). The complication risk profiles of decompression surgeries and fusion surgeries must be balanced with the risk of disk herniation re-recurrence, as both procedures lead to improvements in functional outcomes. [Orthopedics. 2018; 41(4):e457-e469.]., (Copyright 2018, SLACK Incorporated.)

Purpose: The aim of this study was to analyze rates of perioperative complications and subsequent cervical surgeries in patients treated for cervical degenerative disc disease with anterior cervical discectomy and fusion (ACDF) and those treated with artificial cervical disc arthroplasty (ACDA) for up to 5-year follow-up., Methods: California's Office of Statewide Health Planning and Development discharge database was analyzed for patients aged 18-65 years undergoing single-level ACDF or ACDA between 2003 and 2010. Medical comorbidities were identified with CMS-Condition Categories. Readmissions for short-term complications of the procedure were identified and rates of subsequent cervical surgeries were calculated at 90-day and 1-, 3-, and 5-year follow-up. Multivariate regression modeling was used to identify associations with complications and subsequent cervical surgeries correcting for patient and provider characteristics., Results: A total of 52,395 eligible cases were identified: 50,926 ACDF and 1469 ACDA. Readmission was less common in the ACDA group (OR: 0.69, 95% CI: 0.48-1.0, p = 0.048). Subsequent cervical spine surgery was more common in the ACDF group in the immediate perioperative period (within 90 days of surgery) (ACDF 3.35% vs. ACDA 2.04%, OR: 0.63, 95% CI: 0.44-0.92, p = 0.015). At 1-, 3-, and 5-year postoperatively, rates of subsequent cervical surgeries were similar between the two cohorts., Conclusions: We found no protective benefit for ACDA versus ACDF for single-level disease at up to 5-year follow-up in the largest cohort of patients examined to date. Early complications were rare in both cohorts stressing the value of large cohort studies to study risk factors for rare events. These slides can be retrieved under Electronic Supplementary Material.

Study Design: Systematic review and meta-analysis., Objective: Compare the radiographic and clinical outcomes of anterior lumbar interbody fusion (ALIF) to transforaminal lumbar interbody fusion (TLIF)., Summary of Background Data: ALIF and TLIF are 2 methods of achieving spinal arthrodesis. There are conflicting reports with no consensus on the optimal interbody technique to achieve successful radiographic and clinical outcomes. The goal of this systematic review and meta-analysis was to compare the radiographic and clinical outcomes of ALIF to TLIF., Materials and Methods: A systematic search of multiple medical reference databases was conducted for studies comparing ALIF to TLIF. Studies that included stand-alone ALIFs were excluded. Meta-analysis was performed using the random-effects model for heterogeneity. Radiographic outcome measures included segmental and overall lumbar lordosis, and fusion rates. Clinical outcomes measures included Oswestry disability index (ODI) and visual analog scale (VAS) score for back pain., Results: The search yielded 7 studies totaling 811 patients (ALIF=448, TLIF=363). ALIF was superior to TLIF in restoring segmental lumbar lordosis at L4-L5 and L5-S1 (L4-L5; P=0.013, L5-S1; P<0.001). ALIF was also superior to TLIF in restoring overall lumbar lordosis (P<0.001). However, no significant differences in fusion rates were noted between both techniques [odds ratio=0.905; 95% confidence interval, 0.458-1.789; P=0.775]. In addition, ALIF and TLIF were comparable with regards to ODI and VAS scores (ODI; P=0.184, VAS; P=0.983)., Conclusions: For the restoration of lumbar lordosis, ALIF is superior to TLIF. However, TLIF is comparable to ALIF with regards to fusion rate and clinical outcomes.

Although several options are available to address adjacent segment disease (ASD), the most effective surgical treatment has not been determined. In addition, it is important to subdivide ASD into stenosis with or without instability to determine if a decompression alone vs an extension of fusion is necessary. A systematic search of multiple medical reference databases was conducted for studies on surgical treatment of ASD. The primary outcome measures used were radiographic and clinical success rates. Meta-analysis was completed to determine effect summary values, 95% confidence intervals, and Q statistic and I 2 values, using the random effects model for heterogeneity. The search yielded 662 studies, of which 657 were excluded. A total of 5 (level IV) studies with a total of 118 patients were included in this review. In 2 studies (46 patients), stenosis without instability was the indication for reoperation for ASD. However, extension of fusion was the modality of choice for the treatment of ASD in all studies. Overall clinical improvement (in back and/or leg pain scores) was noted in 71.3% of patients (95% confidence interval, 37.4-100), while radiographic fusion was noted in 89.3% of patients (95% confidence interval, 51.2-100). Following reoperation for ASD, revision surgery rates ranged from 4.5% to 23.1% at last clinical follow-up. There is variability in the clinical improvement following lumbar fusion for ASD. In addition, little literature exists regarding the optimal treatment options for patients with ASD for stenosis with or without instability. [Orthopedics. 2018; 41(2):e161-e167.]., (Copyright 2017, SLACK Incorporated.)

Study Design: Systematic review and meta-analysis., Objective: The purpose of this study was to evaluate the effect of postoperative ketorolac administration (ie, dosage and duration of use) on pseudarthrosis following thoracolumbar posterolateral spinal fusions., Summary of Background Data: Ketorolac is a nonsteroidal anti-inflammatory drug often administered for pain control after spine surgery. The main concern with ketorolac is the risk of pseudarthrosis following fusion., Materials and Methods: A systematic search of multiple medical reference databases was conducted for studies detailing postoperative ketorolac use in lumbar fusion and scoliosis surgery in adult and pediatric patients, respectively. Meta-analysis was performed using the random-effects model for heterogeneity as this study analyzes heterogenous patient populations undergoing variable approaches to fusion and variable numbers of levels with variable means of detection of pseudarthrosis. Outcome measure was pseudarthrosis., Results: Overall, 6 studies totaling 1558 patients were reviewed. Pseudarthrosis was observed in 119 (7.6%) patients. Pseudarthrosis were observed in adults with ketorolac administered for >2 days [odds ratio (OR), 3.44, 95% confidence interval (95% CI), 1.87-6.36; P<0.001], adults with doses of ≥120 mg/d (OR, 2.93, 95% CI, 1.06-8.12; P=0.039), and adults with ketorolac administered for >2 days and at doses ≥120 mg/d (OR, 4.75, 95% CI, 2.34-9.62; P<0.001). Ketorolac use in smokers was associated with pseudarthrosis (OR, 8.71, 95% CI, 2.23-34.0; P=0.002)., Conclusion: Ketorolac, when administered for >2 days and/or at a dose of ≥120 mg/d, is associated with pseudarthrosis in adults after posterolateral lumbar fusion. Ketorolac use in smokers is also associated with pseudarthrosis.

Study Design: Retrospective study., Objective: Evaluate the effect of age on the efficacy of allograft/demineralized bone matrix (DBM) enriched with concentrated bone marrow aspirate (BMA) in posterolateral lumbar fusions (PLFs)., Summary of Background Data: Cell-based therapies such as concentrated BMA have been developed as a potential alternative to iliac crest bone graft (ICBG). BMA contains mesenchymal stem cells (MSCs) and growth factors that can confer osteogenic and osteoinductive potential to osteoconductive scaffolds such as DBM/allograft. To date, no studies have examined the role of age on fusion outcomes when BMA is utilized despite the well-established deleterious effects of advanced age on bone marrow and MSC potential., Materials and Methods: Fifty-one patients that underwent PLF were divided into 3 groups. Group A (n=14) composed of patients age 65 years and older who received BMA with DBM. Group B (n=17) consisted of patients younger than 65 years of age who received BMA with DBM. Group C (n=20) composed of patients age 65 years and older who received ICBG. Fusion rates and clinical outcomes were assessed., Results: Fusion was significantly lower in group A (35.7%) compared with both groups B (76.4%) and C (80%) (A vs. B, P=0.03; A vs. C, P=0.01). There were no differences in clinical outcomes among all groups except for pseudarthrosis which occurred in 28.6% of patients in group A compared with none and 5% of patients in groups B and C, respectively (A vs. B, P=0.03; A vs. C, P=0.13)., Conclusions: Elderly patients undergoing PLF using DBM enriched with BMA achieved lower radiographic fusion success compared with their nonelderly counterparts and compared with elderly patients that had fusion with ICBG. This may be partly due to the effect of advanced age on MSC potential.

Background: Intraoperative neuromonitoring (ION) such as motor-evoked potential (MEP), somatosensory evoked potentials (SSEP) and electromyography (EMG) are used to detect impending neurological injuries during spinal surgery. To date, little is known on the trends in the use of ION for scoliosis surgery in the United States., Methods: A retrospective review was performed using the PearlDiver Database to identify patients that had scoliosis surgery with and without ION from years 2005 to 2011. Demographic information (such as age, gender, region within the United States) and clinical information (such as type of ION and rates of neurological injury) were assessed., Results: There were 3618 patients who had scoliosis surgery during the study period. ION was used in 1361 (37.6%) of these cases. The number of cases in which ION was used increased from 27% in 2005 to 46.9% in 2011 (p < 0.0001). Multimodal ION was used more commonly than unimodal ION (64.6% vs. 35.4%). The most commonly used modality was combined SSEP and EMG while the least used modality was MEP only. Neurological injuries occurred in 1.8% and 2.0% of patients that had surgery with and without ION, respectively (p = 0.561). ION was used most commonly in patients < 65 years of age and in the Northeastern part of the United States (age; p = 0.006, region; p < 0.0001)., Conclusions: The use of ION for scoliosis surgery gradually increased annually from 2005 to 2011. Age and regional differences were noted with neuromonitoring being most commonly used for scoliosis surgery in non-elderly patients and in the Northeastern part of the United States. No differences were noted in the risk of neurological injury in patients that had surgery with and without ION. Although the findings from this study may seem to suggest that ION may not influence the risk of neurologic injury, this result must be interpreted with caution as inherently riskier surgeries may utilize ION more, leading to an actual reduction in injuries more dramatic than observed in this study.

Background: Cervical spondylotic myelopathy (CSM) is a disorder that can cause neurologic deterioration. Studies on paraspinal muscular atrophy (PMA) in the lumbar spine have shown that these changes are caused by several perioperative factors. It is possible that PMA in the cervical spine could behave similarly. In this retrospective study, we compared the degree of PMA after laminoplasty versus laminectomy and fusion (LF) using a standard posterior approach to the cervical spine., Methods: 18 laminoplasty and 43 LF patients were included in this study. For each patient, preoperative and postoperative MRI files were obtained and transferred into OsiriX imaging software. Atrophy rate was obtained and reported as percentage change in cross-sectional area of the cervical paraspinal muscles from preoperative to postoperative imaging., Results: Mean cross-sectional cervical muscle atrophy rates were 6% and 13.1% for laminoplasty and LF, respectively, representing a 2.19 times increase in the degree of atrophy (P < 0.001). Independently, LF was associated with a 5.84% increase in the rate of PMA (P = 0.03). Involvement of C3 as the cephalad surgical level was associated with a 5.78% decrease in the rate of PMA (P = 0.03). For each degree increase in postoperative Cobb angle, there was a 0.66% decrease in the rate of PMA (P = 0.02)., Conclusion: PMA should be part of the decision making process when a posterior approach is considered, inasmuch as this study demonstrates that cervical laminoplasty was associated with significantly lower rates of PMA compared with cervical laminectomy and fusion. Additionally, these results suggest that minimizing PMA may help preserve cervical lordosis., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design: A retrospective database study., Objective: The goal of this study was to (1) evaluate the trends in the use of electromyography (EMG) for instrumented posterolateral lumbar fusions (PLFs) in the United States and (2) assess the risk of neurological injury following PLFs with and without EMG., Summary of Background Data: Neurologic injuries from iatrogenic pedicle wall breaches during screw placement are known complications of PLFs. The routine use of intraoperative neuromonitoring (ION) such as EMG during PLF to improve the accuracy and safety of pedicle screw implantation remains controversial., Methods: A retrospective review was performed using the PearlDiver Database to identify patients who had PLF surgery with and without EMG for lumbar disorders from years 2007 to 2015. Patients undergoing concomitant interbody fusions or spinal deformity surgery were excluded. Demographic trends and risk of neurological injuries were assessed., Results: During the study period, 2007 to 2015, 9957 patients underwent PLFs. Overall, EMG was used in 2495 (25.1%) of these patients. There was a steady increase in the use of EMG from 14.9% in 2007 to 28.7% in 2009, followed by a steady decrease to 21.9% in 2015 (P < 0.0001). The risk of postoperative neurological injuries following PLFs was 1.35% (134/9957) with a risk of 1.36% (34/2495) with EMG and 1.34% (100/7462) without EMG (P = 0.932). EMG is used most commonly for PLFs in the Southern part of the United States., Conclusion: In this retrospective national database review, we found that there was a steady increase in the routine use of EMG for PLFs followed by a steady decline. Regional differences were observed in the utility of EMG for PLFs. The risk of neurological complications following PLF in the absence of spinal deformity is low and the routine use of EMG for PLF may not decrease the risk., Level of Evidence: 4.

Background: Laminectomy with fusion (LF) and laminoplasty are two posterior-based surgical approaches for the surgical treatment of cervical spondylotic myelopathy (CSM). The decompressive effect of these approaches is thought to be primarily related to the dorsal drift of the spinal cord away from ventral compressive structures. A lesser known mechanism of spinal cord decompression following cervical LF is regression of the ventral disc osteophyte complexes which is postulated to result from the alteration of motion across the fused motion segment. The goal of this study was to determine whether regression of the ventral disc-osteophyte complexes occur following laminoplasty and compare the magnitude of this occurrence to cervical laminectomy and fusion., Methods: Seventy patients with CSM who underwent pre- and postoperative magnetic resonance imaging (MRI) and were treated with either laminoplasty or LF. The size of the disc-osteophyte complex at all operative levels were measured on pre- and postoperative MRI using digital calipers., Results: The laminoplasty group consisted of 25 patients with an average age of 54.9 and a mean of 3.24 surgical levels while the LF group consisted of 45 patients with an average age of 65.4 and a mean of 3.44 surgical levels (age, p < 0.0001; levels, p= 0.46). The average time interval between pre- and post-operative MRI was 16.2 and 15.6 months in the laminoplasty and LF groups, respectively (p = 0.91). The average time interval between surgery and post-operative MRI was 10.1 and 10.7 months in the laminoplasty and LF groups, respectively (p = 0.86). When comparing pre- and post-operative MRI, there was a 9.59% decrease in disc-osteophyte complex size from 3.84mm ± 0.74 to 3.47mm ± 0.86 in the laminoplasty group compared to a 35.4% decrease in disc-osteophyte complex size from 4.60mm ± 1.06 to 2.98mm ± 1.33 in LF group (laminoplasty, p < 0.0001; LF, p = 0.0067). Using logistic regression analysis, LF, increased time interval between surgery and post-operative MRI, high cobb angle, and straight sagittal alignment were all independently associated with increased disc-osteophyte complex regression (p < 0.05). No differences in functional outcomes (as defined by mJOA scores) was found between the two surgical techniques., Conclusions: In patients with CSM that had a posterior surgical approach, LF is associated with a larger interval regression in disc-osteophyte complex size compared to laminoplasty. This is likely related to the loss of motion of the cervical spine after surgery as governed by Wolff's law and the Heuter-Volkmann's principle. Although the decompressive effect of LF and laminoplasty is primarily related to the dorsal drift of the spinal cord away from ventral compressive structures, disc-osteophyte complex regression likely provides another mechanism of spinal cord decompression.

Study Design: Systematic review and meta-analysis., Objective: The goal of this study was to (i) assess the risk of neurological injury after anterior cervical spine surgery (ACSS) with and without intraoperative neuromonitoring (ION) and (ii) evaluate differences in the sensitivity and specificity of ION for ACSS., Summary of Background Data: Although ION is used to detect impending neurological injuries in deformity surgery, it's utility in ACSS remains controversial., Methods: A systematic search of multiple medical reference databases was conducted for studies on ION use for ACSS. Studies that included posterior cervical surgery were excluded. Meta-analysis was performed using the random-effects model for heterogeneity. Outcome measure was postoperative neurological injury., Results: The search yielded 10 studies totaling 26,357 patients. The weighted risk of neurological injury after ACSS was 0.64% (0.23-1.25). The weighted risk of neurological injury was 0.20% (0.05-0.47) for ACDFs compared with 1.02% (0.10-2.88) for corpectomies. For ACDFs, there was no difference in the risk of neurological injury with or without ION (odds ratio, 0.726; confidence interval, CI, 0.287-1.833; P = 0.498). The pooled sensitivities and specificities of ION for ACSS are 71% (CI: 48%-87%) and 98% (CI: 92%-100%), respectively. Unimodal ION has a higher specificity than multimodal ION [unimodal: 99% (CI: 97%-100%), multimodal: 92% (CI: 81%-96%), P = 0.0218]. There was no statistically significant difference in sensitivities between unimodal and multimodal [68% vs. 88%, respectively, P = 0.949]., Conclusion: The risk of neurological injury after ACSS is low although procedures involving a corpectomy may carry a higher risk. For ACDFs, there is no difference in the risk of neurological injury with or without ION use. Unimodal ION has a higher specificity than multimodal ION and may minimize "subclinical" intraoperative alerts in ACSS., Level of Evidence: 3.

Study Design: A retrospective database study., Objective: The goal of this study was to (1) evaluate the trends in the use of intraoperative neuromonitoring (ION) for anterior cervical discectomy and fusion (ACDF) surgery in the United States and (2) assess the incidence of neurological injuries after ACDFs with and without ION., Summary of Background Data: Somatosensory-evoked potentials (SSEPs) and motor-evoked potentials (MEPs) are the commonly used ION modalities for ACDFs. Controversy exists on the routine use of ION for ACDFs and there is limited literature on national practice patterns of its use., Methods: A retrospective review was performed using the PearlDiver Patient Record Database to identify cases of spondylotic myelopathy and radiculopathy that underwent ACDF from 2007 to 2014. The type of ION modality used and the rates of neurological injury after surgery were assessed., Results: During the study period, 15,395 patients underwent an ACDF. Overall, ION was used in 2627 (17.1%) of these cases. There was a decrease in the use of ION for ACDFs from 22.8% in 2007 to 4.3% use in 2014 (P < 0.0001). The ION modalities used for these ACDFs were quite variable: SSEPs only (48.7%), MMEPs only (5.3%), and combined SSEPs and MMEPs (46.1%). Neurological injuries occurred in 0.23% and 0.27% of patients with and without ION, respectively (P = 0.84). Younger age was associated with a higher utility of ION (<45: 20.3%, 45-54: 19.3%, 55-64: 16.6%, 65-74: 14.3%, and >75: 13.6%, P < 0.0001). Significant regional variability was observed in the utility of ION for ACDFs across the country (West; 21.9%, Midwest; 12.9% (P < 0.0001)., Conclusion: There has been a significant decrease in the use of ION for ACDFs. Furthermore, there was significant age and regional variability in the use of ION for ACDFs. Use of ION does not further prevent the rate of postoperative neurological complications for ACDFs as compared with the cases without ION. The utility of routine ION for ACDFs is questionable., Level of Evidence: 3.

Background: Multiple studies have demonstrated that a significant amount of variability exists in various demineralized bone matrix (DBM) formulations, which casts doubts on its reliability in consistently promoting fusion. Bone marrow aspirate (BMA) is a cellular based graft that contains mesenchymal stem cells (MSCs) and growth factors can confer osteogenic and osteoinductive potential to DBM. The goal of this study was to describe the outcome of DBM enriched with concentrated BMA in patients undergoing combined lumbar interbody and posterolateral fusion., Methods: Eighty patients with a minimum of 12 months of follow-up were evaluated. Fusion and rates of complication were evaluated. Functional outcomes were assessed based on the modified Odom's criteria. Multiple logistic regression analysis was used to examine the effects of independent variables on fusion outcome., Results: The overall rate of solid fusion (i.e patients with both solid posterolateral and interbody fusion) was 81.3% (65/80). Specifically, the radiographic evidence of solid posterolateral and interbody fusions were 81.3% (65/80) and 92.5% (74/80), respectively. Seven (8.75%) patients developed hardware-related complications, 2 (2.5%) patients developed a postoperative infection and 2 (2.5%) patients developed clinical pseudarthrosis. Charlson comorbidity index (CCI) scores of 3 and 4 were associated with non-solid unions (CCI-3, p = 0.048; CCI-4, p = 0.03). Excellent or good outcomes were achieved in 58 (72.5%) patients., Conclusions: Patients undergoing lumbar fusion using an enriched bone graft containing concentrated BMA added to DBM can achieve successful fusion with relatively low complications and good functional outcomes. Despite these findings, more studies with higher level of evidence are needed to better understand the efficacy of this promising graft option.

Purpose: The cortical bone trajectory (CBT) is a novel lumbar pedicle screw trajectory. The aim of this study was to conduct a detailed morphometric measurement of the lumbosacral spine for CBT pedicle screw, using the inferior facet of the cephalad level as a bony landmark., Methods: The three-dimensional computed tomography (3D-CT) scans of 86 adults who underwent examination of the lumbosacral spine were studied. The distances from the starting point to the inferior, lateral and medial border of the inferior facet of the cephalad level were measured. The angles formed between the screw trajectory and the sagittal plane, the superior endplate of the vertebral body and the posterior margin of the pars interarticularis were defined as the transverse angle (TA), cephalad angle 1 (CA1) and cephalad angle 2 (CA2), respectively., Results: The distances from the inferior border of inferior facet to the starting point from L1 to S1 were 8.9, 6.3, 4.1, 2.9, 1.4 and 0 mm, respectively. The distances from the medial border of the inferior facet to the starting point from L1 to S1 were between 3 and 4 mm. TA from L1 to S1 was 9.0°, 9.6°, 11.3°, 13.5°, 15.5°, and 8.2°, respectively. CA1/CA2 from L1 to S1 was 26.7°/38.7°, 26.0°/38.7°, 26.9°/38.0°, 24.4°/37.2°, 22.9°/35.1° and 18.4°/47.8°, respectively. The maximum screw diameters from L1 to S1 were 4.8, 5.1, 6.1, 6.8, 7.8, and 6.1 mm, respectively. Twenty-five millimeter can serve as a safe maximum length of CBT pedicle screws., Conclusions: The inferior facet of the cephalad level is an attractive bony landmark for establishing a starting point of CBT for minimally invasive spine surgery.

Study Design: Retrospective analysis., Objective: To examine complications and rates of subsequent surgery following lumbar spinal fusion (LF) and lumbar total disc arthroplasty (TDA) at up to 5-year follow-up., Summary of Background Data: LF is commonly used in the management of degenerative disc disease causing pain refractory to nonoperative management. Lumbar TDA was developed as an alternative to fusion with the theoretical advantage of reducing rates of adjacent segment pathology and reoperation. Most prior reports comparing these 2 interventions have come from industry-sponsored investigational device exemption trials and no large-scale administrative database comparisons exist., Methods: The California Office of Statewide Health Planning and Development discharge database was queried for patients aged 18 to 65 years undergoing lumbar TDA and LF for degenerative disc disease from 2004 to 2010. Patient characteristics were collected, and rates of complications and readmission were identified. Rates of repeat lumbar surgery were calculated at 90-day and 1-, 3-, and 5-year follow-up intervals., Results: A total of 52,877 patients met the inclusion criteria (LF = 50,462, TDA = 2415). Wound infections were more common following LF than TDA (1.03% vs. 0.25%, P < 0.001). Rates of subsequent lumbar surgery at 90-day and 1-year follow-up were lower with lumbar TDA than LF (90-day-TDA: 2.94% vs. LF: 4.01%, P = 0.007; 1-yr-TDA: 3.46% vs. LF: 4.78%, P = 0.009). However, there were no differences in rates of subsequent lumbar surgery between the 2 groups at 3-year and 5-year follow-up., Conclusion: Lumbar TDA was associated with fewer early reoperations, though beyond 1 year, rates of reoperation were similar. Lumbar TDA may be associated with fewer acute infections, though this may be approach related and unrelated to the device itself., Level of Evidence: 3.

Background: Yolk sac tumors (YST) are malignant neoplasms. They are a subtype of germ cell tumors and typically originate in the gonads although extragonadal origins of such tumors have been described. Yolk sac tumors are commonly found in the gonads of infants and children and are extremely rare in adults. The goal of this case report is to describe the clinical presentation of a rare case of metastatic extragonadal yolk sac tumor originating from the mediastinum and causing an acute conus medullaris syndrome in an adult male., Methods: A 47-year old male presented to our emergency department with a one-day history of bilateral lower extremity weakness, urinary retention and bowel incontinence. Imaging revealed a destructive lesion and a burst fracture of the first lumbar vertebral body (L1) with severe spinal canal stenosis. An urgent spinal decompression and fusion was performed. Oncologic workup revealed a yolk sac tumor originating from the mediastinum., Results: His neurologic function, including motor strength, bowel and bladder function improved in the postoperative period. Chemotherapy regimen of ifosfamide, etoposide and cisplatin was administered and radiation therapy was administered to the spine tumor bed., Conclusions: Yolk sac tumors, although rare, should be considered in the long list differential diagnosis of an otherwise healthy male presenting with conus medullaris or spinal cord compression from metastatic disease without evidence of a testicular mass. Prompt diagnosis with urgent decompression of neural structures and stabilization of the spine may result in improvement in neurological function.

Purpose: Cell-based therapies such as concentrated bone marrow aspirate (BMA) with allograft and demineralized bone matrix (DBM) have been developed as a potential alternative to iliac crest bone graft (ICBG) in spinal fusion. BMA contains mesenchymal stem cells (MSCs) and growth factors that confer osteogenic and osteoinductive potential to osteoconductive scaffolds like allograft and DBM. It is well established that there is an age-related decline in bone marrow MSC population and efficacy. This might be problematic in spine arthrodesis when utilizing BMA derived from elderly patients as a fusion aide. The goal of this study was to describe the outcomes of concentrated BMA with allograft and DBM in elderly patients undergoing posterolateral and interbody lumbar fusion., Methods: Thirty-one patients, age 65 and older, with a minimum of 12 months follow-up underwent combined primary posterolateral and transforaminal lumbar interbody fusion. Radiographic fusion, complications, reoperation rates and clinical outcomes were assessed. Multiple logistic regression analysis was used to examine the effects of variables such as patient age, gender, smoking, osteoporosis, Charlson co-morbidity index score, single versus multilevel fusion, length of hospital stay, and length of follow-up time on fusion outcome., Results: The overall rate of a solid fusion (i.e. the concomitant presence of solid posterolateral and interbody fusion in a patient) was 83.9 % (26/31). Specifically, radiographic evidence of a successful posterolateral fusion was 83.9 % (26/31) while the radiographic evidence of a successful interbody fusion was 96.8 % (30/31). Using logistic regression analysis, none of the variables of interest had an association with non-solid unions. One (3.2 %) patient developed a seroma and one (3.2 %) patient developed clinical pseudarthrosis. None of the patients developed hardware-related complications or graft donor site morbidities. Five (16.1 %) patients required reoperation. Excellent or good results were achieved in 83.9 % of patients., Conclusions: Despite the concerns of reduced fusion potential in elderly patients, autologous concentrated BMA mixed with allograft and DBM in posterolateral and interbody fusions can achieve successful fusion rates with good clinical outcomes and low complication rates.

Background: Antimicrobial drugs used in human infection treatment and animal husbandry may select for drug-resistant bacterial pathogens, which are increasingly observed worldwide. We sought to examine the extent to which identical mobile drug resistance elements are shared across common pathogens isolated from human and animal sources., Methods: We compared the distribution of one class of mobile elements--integrons and gene cassettes--among uropathogenic Escherichia coli isolates, Salmonella enterica serovar Typhimurium isolates from human diarrhea cases, and E. coli and Salmonella isolates from nonhuman sources in the United States. The sequences of the gene cassettes were also compared with those deposited in GenBank., Results: Class 1 integrons were detected in 68 (49%) of 139 uropathogenic E. coli isolates, 16 (72%) of 22 human and animal Salmonella isolates, and 120 (28%) of 436 nonhuman E. coli isolates. The most prevalent cassettes were those encoding aminoglycoside adenyltransferase A (aadA) and dihydrofolate reductase A (dfrA). Sequences of aadA1, dfrA12-orfF-aadA2, and dfrA17-aadA5 gene cassettes from 35 urinary tract infection E. coli isolates and of aadA2 and aadA12 gene cassettes from 7 Salmonella isolates were 100% identical to the corresponding cassette sequences from food animal E. coli isolates and those deposited in GenBank from a wide variety of bacteria isolated from animal hosts from distinct regions of the world., Conclusion: Common community-acquired human drug-resistant infections are caused by bacterial strains that harbor mobile drug resistance determinants of identical sequences that are found in diverse bacterial species from varied animal sources worldwide.

The prevalence of urinary tract infections (UTI) caused by trimethoprim-sulfamethoxazole (TMP-SMX)-resistant Escherichia coli is increasing and varies geographically in the United States. Recent community-based UTI studies have demonstrated geographic clustering of an Escherichia coli clonal group, suggesting occurrence of a community outbreak of UTI. A large proportion of this clonal group (designated CgA) isolated from women in a California college community was found to be resistant to TMP-SMX. We wished to determine if the acquisition of TMP-SMX resistance by CgA occurred before or after the CgA strains were introduced into this community. Between October 1999 and January 2000 and between October 2000 and January 2001, 482 E. coli isolates were consecutively collected from the urine samples of women with UTI at a student health clinic and analyzed for determinants of TMP-SMX resistance. In particular, the distribution of integrons harboring resistance cassettes for TMP-SMX (dfr) was examined. Among 95 TMP-SMX-resistant isolates, 68 and 27 isolates carried class 1 and class 2 integrons, respectively. A class 1 integron was found in 25 (93%) of 27 TMP-SMX-resistant CgA isolates but in only 43 (63%) of 68 TMP-SMX-resistant non-CgA isolates (P < 0.001) and in none of 44 TMP-SMX-susceptible E. coli isolates (P < 0.0001). CgA strains carried only a single arrangement of class 1 gene cassettes (dfrA17-aadA5), while the non-clonal group strains carried nine different cassette arrangements. These results support the idea that CgA strains acquired their resistance at a common site prior to their spread to the college community.