Validation of the AO Spine Thoracolumbar Injury Classification System Treatment Algorithm: Should it be used to Guide Fracture Management?

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

To determine how historical management of thoracolumbar spine injuries compares to the recently proposed AO Spine Thoracolumbar Injury Classification System treatment algorithm.

SUMMARY OF BACKGROUND DATA

Classifications of the thoracolumbar spine are not uncommon. The frequent advent of new classifications is typically due to previous classifications being primarily descriptive or unreliable. Thus, AO Spine created a classification with an associated treatment algorithm to guide injury classification and management.

METHODS

Thoracolumbar spine injuries were retrospectively identified from a prospectively collected spine trauma database at a single, urban, academic medical center during the years 2006-2021. Each injury was classified and assigned points based on the AO Spine Thoracolumbar Injury Classification System injury severity score. Patients were grouped into scores of three or less (preferred initial conservative treatment) and greater than six (preferred initial surgical intervention). Either operative or non-operative treatment was considered appropriate for injury severity scores of four or five.

RESULTS

A total of 815 patients (TL AOSIS 0-3: 486, TL AOSIS 4-5: 150, TL AOSIS 6+: 179) met inclusion status. Injury severity scores of 0-3 were more likely to undergo non-operative management compared to scores of 4-5 or 6+ (99.0% vs. 74.7% vs. 13.4%, P<0.001). Thus, guideline congruent treatment was 99.0%, 100%, and 86.6%, respectively (P<0.001). Most injuries determined to be a 4 or 5 were treated non-operatively (74.7%). Based on the treatment algorithm, 97.5% of patients who received operative treatment and 96.1% who received non-operative treatment were managed in accordance with the algorithm. Of the 29 patients who did not receive algorithm congruent treatment, 5 (17.2%) were treated surgically.

CONCLUSIONS

A retrospective review of thoracolumbar spine injuries at our urban academic medical center identified that patients are historically treated in accordance with the proposed AO Spine Thoracolumbar Injury Classification System treatment algorithm.

Varenicline Mitigates the Increased Risk of Pseudoarthrosis Associated with Nicotine

BACKGROUND CONTEXT

High serum nicotine levels increase the risk of non-union after spinal fusion. Varenicline, a pharmaceutical adjunct for smoking cessation, is a partial agonist designed to displace and outcompete nicotine at its receptor binding site, thereby limiting downstream activation. Given its mechanism, varenicline may have therapeutic benefits in mitigating non-union for active smokers undergoing spinal fusion.

PURPOSE

To compare fusion rate and fusion mass characteristics between cohorts receiving nicotine, varenicline, or concurrent nicotine and varenicline after lumbar fusion.

STUDY DESIGN

Rodent non-instrumented spinal fusion model.

METHODS

Sixty eight-week-old male Sprague-Dawley rats weighing approximately 300 grams underwent L4-5 posterolateral fusion (PLF) surgery. Four experimental groups (control: C, nicotine: N, varenicline: V, and combined: NV [nicotine and varenicline]) were included for analysis. Treatment groups received nicotine, varenicline, or a combination of nicotine and varenicline delivered through subcutaneous osmotic pumps beginning two weeks before surgery until the time of sacrifice at age 14 weeks. Manual palpation testing, microCT imaging, bone histomorphometry, and biomechanical testing were performed on harvested spinal fusion segments.

RESULTS

Control (p=0.016) and combined (p=0.032) groups, when compared directly to the nicotine group, demonstrated significantly greater manual palpation scores. The fusion rate in the control (93.3%) and combined (93.3%) groups were significantly greater than that of the nicotine group (33.3%) (p=0.007, both). Biomechanical testing demonstrated greater Young's modulus of the fusion segment in the control (17.1 MPa) and combined groups (34.5 MPa) compared to the nicotine group (8.07 MPa) (p<0.001, both). MicroCT analysis demonstrated greater bone volume fraction (C:0.35 vs N:0.26 vs NV:0.33) (p<0.001, all) and bone mineral density (C:335 vs N:262 vs NV:328 mg Ha/cm³) (p<0.001, all) in the control and combined groups compared to the nicotine group. Histomorphometry demonstrated a greater mineral apposition rate in the combined group compared to the nicotine group (0.34 vs 0.24 μm/day, p=0.025).

CONCLUSION

In a rodent spinal fusion model, varenicline mitigates the adverse effects of high nicotine serum levels on the rate and quality of spinal fusion.

CLINICAL SIGNIFICANCE

These findings have the potential to significantly impact clinical practice guidelines and the use of pharmacotherapy for active nicotine users undergoing fusion surgery.

Comparing Posterior Lumbar Decompression and Fusion and Transforaminal Lumbar Interbody Fusion in Lumbar Degenerative Spondylolisthesis as Assessed by the CARDS Classification System

STUDY DESIGN

Retrospective cohort study OBJECTIVE: To compare outcomes among Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) subtypes in patients undergoing posterior lumbar decompression and fusion (PLDF) or transforaminal lumbar interbody fusion (TLIF) and evaluate the CARDS system as a tool to guide clinical decisions regarding the treatment of degenerative spondylolisthesis (DS).

METHODS

Patients undergoing PLDF or TLIF for DS from 2010-2020 were identified. Patients were grouped by preoperative CARDS classification. Multivariate analysis was utilized to determine the effects of treatment approach on one-year PROMs and 90-day surgical outcomes.

RESULTS

A total of 1,056 patients were included:148 patients with Type A DS, 323 Type B, 525 Type C, and 60 Type D. Patients with CARDS Types A and C who underwent PLDF experienced longer length of stay and were less likely to be discharged home. There were no differences in revisions, complications, or readmissions between surgical approaches. CARDS Type A patients undergoing PLDF were less likely to achieve MCID for VAS Back (36.8% vs 76.7%, p=0.013). There were no other significant differences in PROMs among CARDS subtypes. TLIF independently predicted better VAS Leg pain improvement at one-year follow-up (β=-2.92, p=0.017) among CARDS Type A patients. Multivariable analysis demonstrated no significant difference in PROMs by surgical approach among other CARDS subtypes.

CONCLUSION

Patients with disc space collapse and endplate apposition (CARDS Type A) appear to benefit from TLIF. However, patients with lumbar spondylolisthesis without disc space collapse or kyphotic angulation (CARDS Type B and C) showed no benefit from additional interbody placement.

Patient-Reported Outcomes Following Anterior and Posterior Surgical Approaches for Multilevel Cervical Myelopathy

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To compare health-related quality of life (HRQoL) outcomes between approach techniques for the treatment of multilevel degenerative cervical myelopathy (DCM).

SUMMARY OF BACKGROUND DATA

Both anterior and posterior approaches for the surgical treatment of cervical myelopathy are successful techniques in the treatment of myelopathy. However, the optimal treatment has yet to be determined, especially for multilevel disease, as the different approaches have separate complication profiles and potentially different impacts on HRQoL metrics.

MATERIALS AND METHODS

Retrospective review of a prospectively managed single institution database of patient-reported outcome measures after 3 and 4-level anterior cervical discectomy and fusion (ACDF) and posterior cervical decompression and fusion (PCDF) for DCM. The electronic medical record was reviewed for patient baseline characteristics and surgical outcomes whereas preoperative radiographs were analyzed for baseline cervical lordosis and sagittal balance. Bivariate and multivariate statistical analyses were performed to compare the two groups.

RESULTS

We identified 153 patients treated by ACDF and 43 patients treated by PCDF. Patients in the ACDF cohort were younger (60.1 ± 9.8 vs . 65.8 ± 6.9 yr; P < 0.001), had a lower overall comorbidity burden (Charlson Comorbidity Index: 2.25 ± 1.61 vs . 3.07 ± 1.64; P = 0.002), and were more likely to have a 3-level fusion (79.7% vs . 30.2%; P < 0.001), myeloradiculopathy (42.5% vs . 23.3%; P = 0.034), and cervical kyphosis (25.7% vs . 7.69%; P = 0.027). Patients undergoing an ACDF had significantly more improvement in their neck disability index after surgery (-14.28 vs . -3.02; P = 0.001), and this relationship was maintained on multivariate analysis with PCDF being independently associated with a worse neck disability index (+8.83; P = 0.025). Patients undergoing an ACDF also experienced more improvement in visual analog score neck pain after surgery (-2.94 vs . -1.47; P = 0.025) by bivariate analysis.

CONCLUSIONS

Our data suggest that patients undergoing an ACDF or PCDF for multilevel DCM have similar outcomes after surgery.

Creation of a Risk Calculator for Predicting New-Onset Cardiac Arrhythmias in Patients Undergoing Lumbar Fusion

INTRODUCTION

As an increasing number of lumbar fusion procedures are being conducted at specialty hospitals and surgery centers, appropriate patient selection and risk stratification is critical to minimizing patient transfers. Postoperative cardiac arrhythmia has been linked to worse patient outcomes and is a common cause of patient transfer. Therefore, we created a risk calculator to predict a patient's likelihood of developing a new-onset postoperative cardiac arrhythmia after lumbar spinal fusion, which may improve preoperative facility selection.

METHODS

A retrospective review was conducted of patients who undergoing lumbar fusion from 2017 to 2021 at a single academic center. Patients were excluded if they had any medical history of a cardiac arrhythmia. Multivariable regression was conducted to determine independent predictors of inpatient arrhythmias. The final regression was applied to a bootstrap to validate an arrhythmia prediction model. A risk calculator was created to determine a patient's risk of new-onset cardiac arrhythmia.

RESULTS

A total of 1,622 patients were included, with 45 patients developing a new-onset postoperative arrhythmia. Age (OR = 1.05; 95% CI, 1.02 to 1.09; P = 0.003), history of beta-blocker use (OR = 2.01; 95% CI, 1.08 to 3.72; P = 0.027), and levels fused (OR = 1.59; 95% CI, 1.20 to 2.00; P = 0.001) were all independent predictors of having a new-onset inpatient arrhythmia. This multivariable regression produced an area under the curve of 0.742. The final regression was applied to a bootstrap prediction modeling technique to create a risk calculator including the male sex, age, body mass index, beta-blocker use, and levels fused (OR = 1.04, [CI = 1.03 to 1.06]) that produced an area under the curve of 0.733.

CONCLUSION

A patient's likelihood of developing postoperative cardiac arrhythmias may be predicted by comorbid conditions and demographic factors including age, sex, body mass index, and beta-blocker use. Knowledge of these risk factors may improve appropriate selection of an outpatient surgical center or orthopaedic specialty hospital versus an inpatient hospital for lumbar fusions.

A Multi-Disciplinary Review of Time-Driven Activity-Based Costing: Practical Considerations for Spine Surgery

STUDY DESIGN

A multi-disciplinary review.

OBJECTIVES

To provide a roadmap for implementing time-driven activity-based costing (TDABC) for spine surgery. This is achieved by organizing and scrutinizing publications in the spine, neurosurgical, and orthopedic literature which utilize TDABC and related methodologies.

METHODS

PubMed and Google Scholar were searched for relevant articles. The articles were selected by two independent researchers. After article selection, data was extracted and summarized into research domains. Preferred reporting items for systematic reviews and meta-analyses (PRISMA) systematic review process was followed.

RESULTS

Of the 524 articles screened, thirty-five articles met the inclusion criteria. Each included article was examined and reviewed to define the primary research question and objective. Comparing different procedures was the most common primary objective. Direct observation along with one other strategy (surveys, interviews, surgical database, or EMR) was most commonly employed during process map development. Across all surgical subspecialties (spine, neurologic, and orthopedic surgery), costs were divided into direct cost, indirect cost, cost to patient, and total costs. The most commonly calculated direct costs included personnel and supply costs. Facility costs, hospital overhead costs, and utilities were the most commonly calculated indirect costs. Transportation costs and parental lost wages were considered when calculating cost to patient. The total cost was a sum of direct costs, indirect costs, and costs to the patient.

CONCLUSION

TDABC provides a common platform to accurately estimate costs of care delivery. Institutions embarking on TDABC for spine surgery should consider the breadth of methodologies highlighted in this review to determine which type of calculations are appropriate for their practice.

Reasons for transfer and subsequent outcomes among patients undergoing elective spine surgery at an orthopedic specialty hospital

Objective

To evaluate the reasons for transfer as well as the 90-day outcomes of patients who were transferred from a high-volume orthopedic specialty hospital (OSH) following elective spine surgery.

Materials and Methods

All patients admitted to a single OSH for elective spine surgery from 2014 to 2021 were retrospectively identified. Ninety-day complications, readmissions, revisions, and mortality events were collected and a 3:1 propensity match was conducted.

Results

Thirty-five (1.5%) of 2351 spine patients were transferred, most commonly for arrhythmia (n = 7; 20%). Thirty-three transferred patients were matched to 99 who were not transferred, and groups had similar rates of complications (18.2% vs. 10.1%; P = 0.228), readmissions (3.0% vs. 4.0%; P = 1.000), and mortality (6.1% vs. 0%; P = 0.061).

Conclusion

Overall, this study demonstrates a low transfer rate following spine surgery. Risk factors should continue to be optimized in order to decrease patient risks in the postoperative period at an OSH.

A Proposal for a Standardized Imaging Algorithm to Improve the Accuracy and Reliability for the Diagnosis of Thoracolumbar Posterior Ligamentous Complex Injury in Computed Tomography and Magnetic Resonance Imaging

STUDY DESIGN

Systematic Literature Review.

OBJECTIVE

To propose a systematic imaging algorithm for diagnosing posterior ligamentous complex (PLC) injury in computed tomography (CT) and magnetic resonance imaging (MRI) to improve the reliability of PLC assessment.

METHODS

A systematic review was conducted following PRISMA guidelines. The Scopus database was searched from its inception until July 21, 2022, for studies evaluating CT or MRI assessment of the PLC injury following thoracolumbar trauma. The studies extracted key findings, objectives, injury definitions, and radiographic modalities.

RESULTS

Twenty-three studies were included in this systematic review, encompassing 2021 patients. Five studies evaluated the accuracy of MRI in detecting thoracolumbar PLC injury using intraoperative findings as a reference. These studies indicate that black stripe discontinuity due to supraspinous or ligamentum flavum rupture is a more specific criterion of PLC injury than high-signal intensity. Thirteen papers evaluated the accuracy or reliability of CT in detecting thoracolumbar PLC injury using MRI or intraoperative findings as a reference. The overall accuracy rate of CT in detecting PLC injury was 68-90%. Two studies evaluate the accuracy of combined CT findings, showing that ≥2 CT findings are associated with a positive predictive value of 88-91 %. Vertebral translation, facet joint malalignment, spinous process fracture, horizontal laminar fracture, and interspinous widening were independent predictors of PLC injury.

CONCLUSION

We provided a comprehensive imaging algorithm for diagnosing PLC in CT and MRI based on available literature and our experience. The algorithm will potentially improve the accuracy and reliability of PLC assessment, however it needs multicentre prospective validation.

Does Facet Distraction Affect Patient Outcomes After ACDF?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study is to determine if there is a correlation between the amount of facet distraction and postoperative patient-reported outcomes after ACDF.

METHODS

A retrospective cohort analysis of patients undergoing 1 to 3 level ACDF for degenerative pathologies at a single academic center was performed. Each patient received upright, lateral cervical spine x-rays at the immediate postoperative time point from which interfacet distance (facet distraction) was measured. Patient-reported outcome measures including NDI, PCS-12, MCS-12, VAS Neck, and VAS Arm pain scores were obtained preoperatively and at short-term (<3 months) and long-term (>1 year) follow-up. Receiver operating curves were generated to evaluate the possibility of a critical interfacet distraction distance. Univariate and multivariate analysis were performed to compare outcomes between groups based on the degree of facet distraction.

RESULTS

A total of 229 patients met the inclusion criteria. Receiver operating curves failed to yield a critical interfacet distraction distance associated with worse post-operative outcomes. Patients were instead grouped based on facet distraction distance below and above the third quartile (0.8mm-2.0 mm, 2.0mm-3.7 mm), with 173 and 56 patients in each respective group. Univariate analysis did not detect any statistically significant differences in outcome measures, recovery ratio, or % MCID achievement at short- and long-term follow-up between groups. Multivariate analysis also failed to demonstrate any significant differences between the facet distraction groups.

CONCLUSION

Increased interfacet distance did not correlate with increased neck pain or disability after an ACDF.

Linking Patterns of Intraoperative Neuromonitoring (IONM) Alerts to the Odds of a New Postoperative Neurological Deficit: Analysis of 27,808 Cervical Spine Procedures From a National Multi-institutional Database

STUDY DESIGN/SETTING

Retrospective review of a national multi-institutional database of 27,808 extradural cervical spine procedures performed between January 2017 and May 2021.

OBJECTIVE

Characterize intraoperative neuromonitoring alerts by the patterns of modalities and nerves/muscles involved and quantify risk of new-onset neurological deficit for patients with a primary diagnosis of myelopathy, stenosis, or radiculopathy.

SUMMARY OF BACKGROUND DATA

Phenotyping alert patterns and linking those patterns with risk is needed to facilitate clinical decision-making.

METHODS

Cases with alerts were categorized by patterns of modalities or nerves/muscles involved, and alert status at closure. Unadjusted odds ratios (ORs) for new-onset neurological deficit were calculated. A mixed-effects logistic regression model controlling for demographic and operative factors, with random intercepts to account for clustering in outcomes by surgeon and surgical neurophysiologist was also used to calculate ORs and probabilities of neurological deficit.

RESULTS

There was significantly increased risk of a new neurological deficit for procedures involving posterior compared with anterior approaches (OR: 1.82, P=0.001) and procedures involving three levels compared with one (OR: 2.17, P=0.001). Odds of a deficit were lower for patients with radiculopathy compared with myelopathy (OR: 0.69, P=0.058). Compared with cases with no alerts, those with unresolved Spinal Cord alerts were associated with the greatest elevation in risk (OR: 289.05) followed by unresolved C5-6 Nerve Root (OR: 172.7), C5-T1 Nerve Root/Arm (OR: 162.89), C7 Nerve Root (OR:84.2), and C8-T1 Nerve Root alerts (OR:75.49, all P<0.001). Significant reductions in risk were seen for resolved Spinal Cord, C5-6 Nerve Root, and C8-T1 nerve alerts. Overall, unresolved motor evoked potential and somatosensory evoked potential alerts were associated with the greatest elevation in risk (OR:340.92) followed by unresolved motor evoked potential-only (OR:140.6) and unresolved somatosensory evoked potential-Only alerts (OR:78.3, all P<0.001). These relationships were similar across diagnostic cohorts.

CONCLUSIONS

Risk elevation and risk mitigation after an intraoperative neuromonitoring alert during surgery is dependent on the type and pattern of alert.

Cellular Bone Matrix Leading to Disseminated Tuberculosis After Spinal Fusion: A Report of 2 Cases

CASE

Although implanted tuberculosis (TB) is rare, a single lot of cellular bone matrix was found to be infected with TB, leading to devastating outcomes. We present 2 cases referred to our institution because of instrumentation failure caused by TB inoculation of cellular bone matrix.

CONCLUSION

Irrespective of spinal region of implanted TB infection, excision of infected bone, extensive irrigation and debridement, and instrumented stabilization are of primary importance to ensure TB eradication and adequate stabilization.

Six-Year Follow-up of a Randomized Controlled Trial of i-FACTOR Peptide-Enhanced Bone Graft Versus Local Autograft in Single-Level Anterior Cervical Discectomy and Fusion

BACKGROUND

Previous analyses of the US Food and Drug Administration (FDA) Investigational Device Exemption study demonstrated the superiority of i-FACTOR compared with local autograft bone in single-level anterior cervical discectomy and fusion (ACDF) at 12 and 24 months postoperatively in a composite end point of overall success.

OBJECTIVE

To report the final, 6-year clinical and radiological outcomes of the FDA postapproval study.

METHODS

Of the original 319 subjects enrolled in the Investigational Device Exemption study, 220 participated in the postapproval study (106 i-FACTOR and 114 control).

RESULTS

The study met statistical noninferiority success for all 4 coprimary end points. Radiographic fusion was achieved in 99% (103/104) and 98.2% (109/111) in i-FACTOR and local autograft subjects, mean Neck Disability Index improvement from baseline was 28.6 (24.8, 32.3) in the i-FACTOR and 29.2 (25.6, 32.9) in the control group, respectively (noninferiority P < .0001). The neurological success rate at 6 years was 95.9% (70/73) in i-FACTOR subjects and 93.7% (70/75) in local autograft subjects (noninferiority P < .0001). Safety outcomes were similar between the 2 groups. Secondary surgery on the same or different cervical levels occurred in 20/106 (18.9%) i-FACTOR subjects and 23/114 (20.2%) local autograft subjects ( P = .866). Secondary outcomes (pain, SF-36 physical component score and mental component score) in i-FACTOR subjects were similar to those in local autograft subjects.

CONCLUSION

i-FACTOR met all 4 FDA-mandated noninferiority success criteria and demonstrated safety and efficacy in single-level anterior cervical discectomy and fusion for cervical radiculopathy through 6 years postoperatively. Safety outcomes are acceptable, and the clinical and functional outcomes observed at 12 and 24 months remained at 72 months.

The impact of demineralized bone matrix characteristics on pseudarthrosis and surgical outcomes after posterolateral lumbar decompression and fusion

Objectives

The objectives of our study were to compare the fusion rates and surgical outcomes of lumbar fusion surgery based on the (1) type of demineralized bone matrix (DBM) carrier allograft, (2) the presence/absence of a carrier, and (3) the presence of bone fibers in DBM.

Methods

Patients >18 years of age who underwent single-level posterolateral decompression and fusion (PLDF) between L3 and L5 between 2014 and 2021 were retrospectively identified. We assessed bone grafts based on carrier type (no carrier, sodium hyaluronate carrier, and glycerol carrier) and the presence of bone fibers. Fusion status was determined based on a radiographic assessment of bony bridging, screw loosening, or change in segmental lordosis >5°. Analyses were performed to assess fusion rates and surgical outcomes.

Results

Fifty-four patients were given DBM with a hyaluronate carrier, 75 had a glycerol carrier, and 94 patients were given DBM without a carrier. DBM carrier type, bone fibers, and carrier presence had no impact on 90-day readmission rates (P = 0.195, P = 0.099, and P = 1.000, respectively) or surgical readmissions (P = 0.562, P = 0.248, and P = 0.640, respectively). Multivariable logistic regression analysis found that type of carrier, presence of fibers (odds ratio [OR] = 1.106 [0.524-2.456], P = 0.797), and presence of a carrier (OR = 0.701 [0.370-1.327], P = 0.274) were also not significantly associated with successful fusion likelihood.

Conclusion

Our study found no significant differences between DBM containing glycerol, sodium hyaluronate, or no carrier regarding fusion rates or surgical outcomes after single-level PLDF. Bone particulates versus bone fibers also had no significant differences regarding the likelihood of bony fusion.

Development of a comprehensive assessment tool to measure the quality of care for individuals with traumatic spinal cord injuries

OBJECTIVE

To develop a comprehensive assessment tool to evaluate the Quality of Care (QoC) in managing individuals with traumatic spinal cord injuries (TSCI).

METHOD

At first, the concepts of QoC for TSCI were identified by conducting a qualitative interview along with re-evaluation of the results of a published scoping review (conceptualization). After operationalization of indicators, they were valued by using the expert panel method. Afterward, the content validity index (CVI) and content validity ratio (CVR) were calculated and served as cut-offs for indicator selection. Then specific questions were developed for each indicator and classified into three categories: pre-hospital, in-hospital, and post-hospital. Data availability of the National Spinal Cord Injury Registry of Iran (NSCIR-IR) was subsequently used to design questions that represent indicators in an assessment tool format. The comprehensiveness of the tool was evaluated using a 4-item Likert scale by the expert panel.

RESULT

Twelve experts participated in conceptualization and 11 experts participated in operationalization phase. Overall, 94 concepts for QoC were identified from published scoping review (87 items) and qualitative interviews (7 items). The process of operationalization and indicator selection led to the development of 27 indicators with acceptable content validity. Finally, the assessment tool contained three pre-hospital, twelve in-hospital, nine post-hospital, and three mixed indicators. Ninety-one percent of experts evaluated the entire tool as comprehensive.

CONCLUSION

Our study presents a health-related QoC tool that contains a comprehensive set of indicators to assess the QoC for individuals with TSCI. However, this tool should be used in various situations to establish construct validity further.

Predictors of Academic Productivity Among Spine Surgeons

INTRODUCTION

The relationship between research productivity in training and future productivity as an attending spine surgeon is not well-established in the literature nor has the effect of geographic location of training institutions on future academic success been investigated. The aim of our study was to (1) summarize characteristics of academically productive spine surgeons, (2) assess predictors of long-term academic productivity, and (3) establish the effect of geographic location on long-term academic productivity.

METHODS

A query was conducted of the 2021 to 2022 North American Spine Society Spine Fellowship Directory of all orthopaedic and neurosurgical spine fellowship selection committee members for each institution participating in the spine fellowship match. The attending publication rate and h-index were determined. A multivariate linear regression model was developed. P value was set to <0.05.

RESULTS

We identified 310 orthopaedic and neurosurgical spine surgeons, representing 76 fellowship programs. Multivariate linear regression analysis identified that the publications during residency (P < 0.001) and during fellowship (P < 0.001) were significant predictors of an increased publication rate as an attending surgeon. By contrast, the preresidency publication rate (P = 0.729) was not significantly predictive of the attending publication rate. Multivariate analysis of h-index found that residency publication rate had a positive correlation (P = 0.031) compared with preresidency (P = 0.579) or fellowship (P = 0.257) rates. Attendings who had attended residency in the Northeast and currently practicing in the Northeast had a higher publication rate (P < 0.001 and P = 0.004, respectively).

DISCUSSION

A higher number of publications in residency and fellowship were markedly predictive of an increased publication rate as an attending spine surgeon. By contrast, preresidency publications may not be indicative of future academic productivity as an attending. Location may also contribute to attending publication rate and favor those who undergo residency training and ultimately practice in the Northeast.

Trends in Short Construct Lumbar Fusions Over the Past Decade at a Single Institution

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

(1) To compare the rates of fusion techniques over the last decade; (2) to identify whether surgeon experience affects a surgeon's preferred fusion technique; (3) to evaluate differences in complications, readmissions, mortality, and patient-reported outcomes measures (PROMs) based on fusion technique.

SUMMARY OF BACKGROUND DATA

Database studies indicate the number of lumbar fusions have been steadily increasing over the last two decades; however, insufficient granularity exists to detect if surgeons' preferences are altered based on additive surgical experience.

METHODS

A retrospective review of continuously collected patients undergoing lumbar fusion at a single urban academic center was performed. Rates of lumbar fusion technique: posterolateral decompression fusion (PLDF), transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion + PLDF (ALIF), and lateral lumbar interbody fusion + PLDF (LLIF) were recorded. Inpatient complications, 90-day readmission, and inpatient mortality were compared with χ 2 test and Bonferroni correction. The Δ 1-year PROMs were compared with the analysis of variance.

RESULTS

Of 3938 lumbar fusions, 1647 (41.8%) were PLDFs, 1356 (34.4%) were TLIFs, 885 (21.7%) were ALIFs, and 80 (2.0%) were lateral lumbar interbody fusions. Lumbar fusion rates increased but interbody fusion rates (2012: 57.3%; 2019: 57.6%) were stable across the study period. Surgeons with <10 years of experience performed more PLDFs and less ALIFs, whereas surgeons with >10 years' experience used ALIFs, TLIFs, and PLDFs at similar rates. Patients were more likely to be discharged home over the course of the decade (2012: 78.4%; 2019: 83.8%, P <0.001). No differences were observed between the techniques in regard to inpatient mortality ( P =0.441) or Δ (postoperative minus preoperative) PROMs.

CONCLUSIONS

Preferred lumbar fusion technique varies by surgeon preference, but typically remains stable over the course of a decade. The preferred fusion technique did not correlate with differences in PROMs, inpatient mortality, and patient complication rates.

LEVELS OF EVIDENCE

3-treatment.

Facet Distraction and Dysphagia: A Prospective Evaluation of This Common Postoperative Issue Following Anterior Cervical Spine Surgery

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

Our primary study was to investigate whether the degree of postoperative facet and disk space distraction following anterior cervical discectomy and fusion (ACDF) affects the rate of postoperative dysphagia.

SUMMARY OF BACKGROUND DATA

Although ACDF is safe and well tolerated, postoperative dysphagia remains a common complication. Intervertebral disk space distraction is necessary in ACDF to visualize the operative field, prepare the endplates for fusion, and facilitate graft insertion. However, the degree of distraction tolerated, before onset of dysphagia, is not well characterized ACDF.

MATERIALS AND METHODS

A prospective cohort study was conducted of 70 patients who underwent ACDF between June 2018 and January 2019. Two independent reviewers measured all preoperative and postoperative radiographs measured for interfacet distraction distance and intervertebral distraction distance, with intrareviewer reproducibility measurements after one month. For multilevel surgery, the level with the greatest distraction was measured. Primary outcomes were numerical dysphagia (0-10), Eating Assessment Tool 10, and Dysphagia Symptom Questionnaire score collected at initial visit and two, six, 12, and 24 weeks postoperatively.

RESULTS

A total of 70 patients were prospectively enrolled, 59 of whom had adequate radiographs. An average of 1.71 (SD: 0.70) levels were included in the ACDF construct. Preoperatively, 13.4% of patients reported symptoms of dysphagia, which subsequently increased in the postoperative period at through 12 weeks postoperatively, before returning to baseline at 24 weeks. Intrareviewer and interreviewer reliability analysis demonstrated strong agreement. There was no relationship between interfacet distraction distance/intervertebral distraction distance and dysphagia prevalence, numerical rating, Eating Assessment Tool 10, or Dysphagia Symptom Questionnaire.

CONCLUSIONS

Patients who had an ACDF have an increased risk of dysphagia in the short term, however, this resolved without intervention by six months. Our data suggests increased facet and intervertebral disk distraction does not influence postoperative dysphagia rates.

LEVEL OF EVIDENCE

3.

Do On-Table Radiographs Predict Postoperative Sagittal Alignment after Posterior Lumbar Fusion?

STUDY DESIGN

Retrospective Cohort Study OBJECTIVE: To determine if intraoperative on-table lumbar lordosis and segmental lordosis correlate with postoperative lordosis following single-level posterolateral decompression and fusion (PLDF) or transforaminal lumbar interbody fusion (TLIF).

METHODS

Electronic medical records were reviewed for patients ≥18 years old who underwent PLDF or TLIF between 2012 and 2020. Lumbar lordosis and segmental lordosis were compared between pre-, intra-, and post-operative radiographs using paired t-tests. Significance was set at p<0.05.

RESULTS

A total of 200 patients met inclusion criteria. No significant differences in preoperative, intraoperative, or postoperative measurements were found between groups. Patients who underwent PLDF experienced less disc height loss over one year postoperatively (PLDF: 0.45 + 0.9 mm vs TLIF: 1.2 + 1.4 mm, p<0.001). Lumbar lordosis significantly decreased between intraoperative to postoperative radiographs at 2-6 weeks for PLDF (Δ: -4.0°, p<0.001) and TLIF (Δ: -5.6°, p<0.001), but no change was identified between the intraoperative and >6 month postoperative radiographs for PLDF (Δ: -0.3°, p=0.634) or TLIF (Δ: -1.6°, p=0.087). Segmental lordosis significantly increased from the preoperative to post-instrumentation intraoperative radiographs for PLDF (Δ: 2.7°, p<0.001) and TLIF (Δ: 1.8°, p<0.001), but it subsequently decreased at the final follow up for PLDF (Δ: -1.9°, p<0.001) and TLIF (Δ: -2.3°, p<0.001).

CONCLUSION

Subtle decreases in lumbar lordosis may be noticed in the early postoperative radiographs compared to intraoperative images on Jackson operative tables. However, these changes are not present at one-year follow-up as lumbar lordosis increases to a similar level as intraoperative fixation.

Evaluating Nonoperative Treatment for Low Back Pain in the Presence of Modic Changes: A Systematic Review

OBJECTIVE

The objective of this study was to summarize and assess the current literature evaluating nonoperative treatments for patients with Modic changes (MCs) and low back pain (LBP).

METHODS

A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The PubMed database was searched from its inception until May 1, 2022 for studies evaluating MC and clinical outcomes. Key findings, treatment details, and patient information were extracted from included studies. Study quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

Eighteen studies were included in this review, encompassing a total of 2452 patients, 1713 of whom displayed baseline MC. Seventy-eight percent of studies were high quality. Of included studies, 2 evaluated antibiotics, 5 evaluated steroid injections, 6 evaluated conservative therapies, and 5 evaluated other treatment modalities. Antibiotics and bisphosphonates improved treatment in patients with MC. Patients with MC without disc herniation benefited from conservative therapy, while those with Type I Modic changes and disc herniation experienced poorer improvement. Significant variability exists in reported outcomes following steroid injections.

CONCLUSIONS

Nonoperative therapy may provide patients with MC with significant benefits. Patients may benefit from therapies not traditionally utilized for LBP such as antibiotics or bisphosphonates, but conservative therapy is not recommended for patients with concomitant MC and disc herniation. The large variation in follow-up times and outcome measures contributes to significant heterogeneity in studies and inability to predict long-term patient outcomes. More long-term studies are needed to assess nonoperative treatments for LBP in patients with MC.

Management of C0 Sacral Fractures Based on the AO Spine Sacral Injury Classification: A Narrative Review

The Arbeitsgemeinschaft fur Osteosynthese fragen Spine Sacral Injury Classification hierarchically separates fractures based on their injury severity with A-type fractures representing less severe injuries and C-type fractures representing the most severe fracture types. C0 fractures represent moderately severe injuries and have historically been referred to as nondisplaced "U-type" fractures. Injury management of these fractures can be controversial. Therefore, the purpose of this narrative review is to first discuss the Arbeitsgemeinschaft fur Osteosynthese fragen Spine Sacral Injury Classification System and describe the different fracture types and classification modifiers, with particular emphasis on C0 fracture types. The narrative review will then focus on the epidemiology and etiology of C0 fractures with subsequent discussion focused on the clinical presentation for patients with these injuries. Next, we will describe the imaging findings associated with these injuries and discuss the injury management of these injuries with particular emphasis on operative management. Finally, we will outline the outcomes and complications that can be expected during the treatment of these injuries.

Does a High Postoperative Opioid Dose Predict Chronic Use After ACDF?

OBJECTIVE

The purpose of this study is to determine if increased postoperative prescription opioid dosing is an isolated predictor of chronic opioid use after anterior cervical diskectomy and fusion (ACDF).

METHODS

A retrospective cohort analysis of patients undergoing ACDF for degenerative diseases from 2016-2019 at a single institution was performed. Preoperative and postoperative opioid and benzodiazepine prescriptions, including morphine milligram equivalents (MMEs) and duration of use, were obtained from the Pennsylvania Prescription Drug Monitoring Program. Univariate analysis compared patient demographics and surgical factors across groups on the basis of postoperative opioid dose (high: MME ≥90, low: MME <90) and chronicity of use (chronic: ≥120 days or >10 prescriptions). Logistic regressions identified predictors of high opioid dose and chronic use.

RESULTS

A total of 385 patients were included. Preoperative opioid tolerance and tobacco use were associated with high postoperative opioid dose and chronic usage. Younger age correlated with high-dose prescriptions. Increased body mass index and preoperative benzodiazepine use were associated with chronic opioid use. Chronic postoperative opioid use correlated with high-dose prescriptions, change in opioid prescribed, private pay scripts, and more than 1 prescriber and pharmacy. Logistic regression identified high postoperative opioid dose, opioid tolerance, increased body mass index, and no prior cervical surgery as predictors of chronic opioid use. Regression analysis determined younger age, increased medical comorbidities, and opioid tolerance to be predictors for high MME prescriptions.

CONCLUSIONS

High postoperative opioid dose independently predicted chronic opioid use after ACDF regardless of preoperative opioid tolerance.

Do Patient Outcomes Predict Loss to Long-Term Follow-Up After Spine Surgery?

OBJECTIVE

To determine if spine surgery patients with greater improvement in patient-reported outcomes measures (PROMs) at early postoperative follow-up are more likely to be lost to follow-up at the 1-year and 2-year postoperative visits.

METHODS

All patients older than 18 years who underwent primary or revision decompression or fusion surgery for degenerative spinal conditions at an academic institution were retrospectively identified. Univariate analysis compared patient demographics, surgical factors, and changes in short-term and long-term postoperative PROMs (Neck Disability Index, Oswestry Disability Index, visual analog scale [VAS] neck, VAS arm, VAS back, VAS leg, and Short-Form 12 Physical and Mental Component Scores) across groups with and without 1 year and 2 years follow-up. Logistic regression isolated predictors of loss to follow-up.

RESULTS

A total of 1412 patients were included. Younger patient age, primary surgery, and single surgical approach independently predicted loss at 1 year follow-up. Female sex predicted loss at 2 years follow-up, whereas multilevel fusion surgery predicted attendance at 2 years clinical follow-up. In patients lost at 1 year follow-up compared with those who attended, preoperative to 3-month Mental Component Score and VAS neck pain improvement was significantly greater. When comparing patients based on 2 years follow-up status, VAS back pain improvement at 1 year postoperatively was significantly greater in patients lost to 2 years follow-up. All other changes in PROMs did not differ significantly by 1 or 2 years follow-up attendance.

CONCLUSIONS

Overall patient outcomes were not found to affect loss to long-term follow-up after spine surgery. The general lack of association between postoperative follow-up status and clinical outcome may limit bias introduced in retrospective PROM studies.

Patients with radiculopathy have worse baseline disability and greater improvements following anterior cervical discectomy and fusion compared to patients with myelopathy

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) is commonly performed in patients with radiculopathy and myelopathy. Although the goal of surgery in patients with radiculopathy is to improve function and reduce pain, patients with myelopathy undergo surgery to halt disease progression. Although the expectations between these preoperative diagnoses are generally understood to be disparate by spine surgeons, there is limited literature demonstrating their discordant outcomes.

PURPOSE

To compare improvements in patient reported outcome measures (PROMs) for patients undergoing ACDF for myelopathy or radiculopathy. Secondarily, we analyzed the proportion of patients who attain the minimum clinically important difference (MCID) postoperatively using thresholds derived from radiculopathy, myelopathy, and mixed cohort studies.

STUDY DESIGN/SETTING

Single institution retrospective cohort study PATIENT SAMPLE: Patients undergoing primary, elective ACDF with a preoperative diagnosis of radiculopathy or myelopathy and a complete set of preoperative and one-year postoperative PROMs.

OUTCOME MEASURES

Outcome measures included the following PROMs: Short-Form 12 Physical Component (PCS-12) and Mental Component (MCS-12) scores, the Visual Analog Scale (VAS) Arm score, and the Neck Disability Index (NDI). Hospital readmissions and revision surgery were also collected and evaluated.

METHODS

Patients undergoing an ACDF from 2014 to 2020 were identified and grouped based on preoperative diagnosis (radiculopathy or myelopathy). We utilized "general MCID" thresholds from a cohort of patients with degenerative spine conditions, and "specific MCID" thresholds generated from cohorts of patients with myelopathy or radiculopathy, respectively. Multivariate linear regressions were performed for delta (∆) PROMs and multivariate logistic regressions were performed for both general and specific MCID improvements.

RESULTS

A total of 798 patients met inclusion criteria. Patients with myelopathy had better baseline function and arm pain (MCS-12: 49.6 vs 47.6, p=.018; VAS Arm: 3.94 vs 6.02, p<.001; and NDI: 34.1 vs 41.9, p<.001), were older (p<.001), had more comorbidities (p=.014), more levels fused (p<.001), and had decreased improvement in PROMs following surgery compared to patients with radiculopathy (∆PCS-12: 4.76 vs 7.21, p=.006; ∆VAS Arm: -1.69 vs -3.70, p<.001; and ∆NDI: -11.94 vs -18.61, p<.001). On multivariate analysis, radiculopathy was an independent predictor of increased improvement in PCS-12 (β=2.10, p=.019), ∆NDI (β=-5.36, p<.001), and ∆VAS Arm (β=-1.93, p<.001). Radiculopathy patients were more likely to achieve general MCID improvements following surgery (NDI: Odds ratio (OR): 1.42, p=.035 and VAS Arm: OR: 2.98, p<.001), but there was no difference between patients with radiculopathy or myelopathy when using radiculopathy and myelopathy specific MCID thresholds (MCS-12: p=.113, PCS-12: p=.675, NDI: p=.108, and VAS Arm: p=.314).

CONCLUSIONS

Patients undergoing ACDF with myelopathy or radiculopathy represent two distinct patient populations with differing treatment indications and clinical outcomes. Compared to radiculopathy, patients with myelopathy have better baseline function, decreased improvement in PROMs, and are less likely to reach MCID using general threshold values, but there is no difference in the proportion reaching MCID when using specific threshold values.

LEVEL OF EVIDENCE

IRB.

Modified Frailty Index Does Not Provide Additional Value in Predicting Outcomes in Patients Undergoing Elective Transforaminal Lumbar Interbody Fusion

OBJECTIVE

To determine the predictive value of the modified Frailty Index (mFI) in evaluating sarcopenia and clinical outcomes in patients undergoing 1-level or 2-level transforaminal lumbar interbody fusion (TLIF).

METHODS

Patients who underwent a 1-level or 2-level TLIF between 2012 and 2020 were retrospectively identified. Frailty was compared among groups using mFI, and sarcopenia was classified by the psoas muscle cross-sectional area. Bivariate statistics compared demographics, comorbidities, and clinical outcomes. A linear regression model was developed using the Charlson Comorbidity Index (CCI) or mFI as independent variables to determine potential predictors for improvement in 1-year patient-reported outcomes.

RESULTS

Of 488 included patients, 60 were severely frail and 60 patients had sarcopenia, but sarcopenia was not associated with patient frailty (P = 0.469). Severely frail patients had worse baseline Oswestry Disability Index (ODI) (P < 0.001), Mental Component Score-12 (P = 0.001), and Physical Component Score-12 (P < 0.001), and worse improvement in ODI (P = 0.037), Physical Component Score-12 (P < 0.001), and visual analog scale (VAS) back (P = 0.007). mFI was an independent predictor of poorer improvement in VAS back and ODI, whereas age + CCI in addition predicted poorer improvement in VAS leg. Patients with higher mFI experienced longer length of stay, less frequent home discharge, and higher rates of complications, but similar readmission and reoperation rates.

CONCLUSIONS

Frailer patients experience poorer improvement in back pain, physical functioning, and disability after TLIF. mFI and the combination of age and CCI comparably predict patient-reported outcomes but do not correlate to baseline sarcopenia. Frailty increased the risk of complications, length of hospital stay, and risk of nonhome discharge.