Comparison Between Three- and Four-Level Anterior Cervical Discectomy and Fusion: Patient-Reported and Radiographic Outcomes

OBJECTIVE

We compared the long-term clinical and radiographic outcomes after 3- and 4-level anterior cervical discectomy and fusion (ACDF) in a retrospective cohort study.

METHODS

Patients who had undergone primary 3- or 4-level ACDF were retrospectively identified. The demographic data and patient-reported outcome measures (PROMs) were collected through a review of the medical records. PROM surveys were administered preoperatively for baseline measurements and at 1 year postoperatively. The surveys included the Neck Disability Index, 12-item short-form physical component summary, 12-item short-form mental component summary, and visual analog scale (VAS) scores for neck and arm pain. The cervical sagittal alignment parameters included C2-C7 lordosis, segmental lordosis, the sagittal vertical axis (SVA), and the T1 slope. Multivariate regression models were used to compare the changes in the PROMs and radiographic measurements over time between 3- and 4-level ACDF. Correlation coefficients were calculated to compare the delta scores for the PROMs and radiographic measurements.

RESULTS

The VAS scores for neck and arm pain had significantly improved from baseline in both cohorts. Only the 3-level group showed significant improvements perioperatively in the Neck Disability Index and 12-item short-form physical component summary. No significant differences were found in the improvement in clinical outcomes between the 2 groups. The pooled results demonstrated a significant negative correlation between the perioperative changes in segmental lordosis and VAS scores for arm pain. A significant negative correlation was also found between the perioperative changes in the SVA and 12-item short-form mental component summary and VAS scores for neck pain. C2-C7 lordosis significantly increased postoperatively only in the 3-level ACDF group.

CONCLUSIONS

Patients undergoing both 3- and 4-level ACDF experienced significant clinical improvement without significant differences between the 2 groups. The radiographic measures of segmental lordosis and SVA also correlated with the changes in clinical outcomes.

How do C2 tilt and C2 slope correlate with patient reported outcomes in patients after anterior cervical discectomy and fusion?

BACKGROUND/CONTEXT

C2 tilt and C2 slope are quick and easy measurements to obtain on lateral radiographs and may be used to determine overall cervical sagittal alignment; however, the influence of these measurements on patient outcomes has not been well established in literature.

PURPOSE

To determine if C2 tilt and/or C2 slope predict patient outcomes better compared with conventional radiographic measures after an anterior cervical discectomy and fusion (ACDF).

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

A total of 249 patients who underwent 1 to 3 level ACDF to address radiculopathy and/or myelopathy at a single academic institution between 2011 and 2015 were identified. Patients with less than 1 year of follow-up were excluded.

OUTCOME MEASURES

Patient Reported Outcomes: Neck Disability Index (NDI), Physical Component Score-12 (PCS-12), and Mental Component Score (MCS-12), Visual Analog Score (VAS) Neck and Arm scores Cervical radiographic measurements: C2 tilt, C2 slope, C2-C7 lordosis, cervical SVA, T1 slope, T1 slope minus cervical lordosis (TS-CL), and C2-C7 ROM METHODS: Pearson correlation tests were performed to assess for significant associations between radiographic measurements and patient outcomes. Multiple linear regression models were developed adjusting for demographics and radiographic parameters to determine which factors were predictive of patient outcomes.

RESULTS

C2 tilt and TS-CL correlated with all postoperative physical outcome scores (NDI, PCS-12, VAS Neck and ARM; p<.05), however no association was seen between C2 slope and postoperative outcomes. After accounting for the presence of subaxial deformity, C2 tilt and TS-CL remained strongly correlated to patient outcome scores. With multiple linear regression, C2 tilt was a significant predictor for NDI, whereas TS-CL was a significant predictor for PCS-12, VAS Neck and VAS Arm.

CONCLUSIONS

C2 tilt significantly correlated with well-described conventional cervical parameters as well as postoperative physical outcomes measures, especially NDI, on multivariate analysis. C2 tilt may provide an easy and practical tool for predicting physical outcomes after ACDF.

Lumbar Pedicle Morphology and Vertebral Dimensions in Isthmic and Degenerative Spondylolisthesis-A Comparative Study

BACKGROUND

The pedicle screw is the most common device used to achieve fixation in fusion of spondylolistheses. Safe and accurate placement with this technique relies on a thorough understanding of the bony anatomy. There is a paucity of literature comparing the surgically relevant osseous anatomy in patients with a degenerative spondylolisthesis (DS) and an isthmic spondylolisthesis (IS). The goal of this study was to determine the differences in the osseous anatomy in patients with a DS and those with an IS.

METHODS

A retrospective comparative cohort study was conducted on patients with a single-level, symptomatic L4-L5 DS or a single-level, symptomatic L5-S1 IS. Magnetic resonance imaging for these patients was reviewed. Morphometries of the pedicle and vertebral body were analyzed by 2 independent observers for the levels from L3 to S1, and radiographic parameters were compared between groups.

RESULTS

A total of 572 levels in 143 patients were studied, including 103 patients with a DS and 40 with an IS. After accounting for confounders, IS and DS had an independent effect on transverse vertebral body width, pedicle height and width, and sagittal pedicle angle. Patients with an IS had a smaller pedicle height (P < .001) and pedicle width (P = .001) than patients with DS. In addition, the angulation of the pedicles varied on the basis of the diagnosis.

CONCLUSIONS

The osseous anatomy is significantly different in patients with a DS than with an IS. Patients with an IS have smaller pedicles in the lumbar spine. Also, the L4 and L5 pedicles are more caudally angulated and the S1 pedicle is less medialized.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Understanding the differences in pedicle anatomy is important for the safe placement of pedicle screws.

Combined Depression and Anxiety Influence Patient-Reported Outcomes after Lumbar Fusion

BACKGROUND

Currently, no studies have assessed what effect the presence of both anxiety and depression may have on patient-reported outcome measurements (PROMs) compared to patients with a single or no mental health diagnosis.

METHODS

Patients undergoing 1- to 3-level lumbar fusion at a single academic hospital were retrospectively queried. Anyone with depression and/or anxiety was identified using an existing clinical diagnosis in the medical chart. Patients were separated into 3 groups: no depression or anxiety (NDA), depression or anxiety alone (DOA), and combined depression and anxiety (DAA). Absolute PROMs, recovery ratios, and the percentage of patients achieving minimal clinically important difference (% MCID) between groups were compared using univariate and multivariate analysis.

RESULTS

Of the 391 patients included in the cohort, 323 (82.6%) were in the NDA group, 37 (9.5%) in the DOA group, and 31 (7.9%) in the DAA group. Patients in the DAA group had significantly worse outcome scores before and after surgery with respect to Short Form-12 mental component score (MCS-12) and Oswestry Disability Index (ODI) scores (P <.001); however, the change in PROMs, recovery ratio, % MCID were not found to be significantly different between groups. Using multivariate analysis, the DAA group was found to be an independent predictor of worse improvement in MCS-12 and ODI scores (P = .026 and P = .001, respectively).

CONCLUSIONS

Patients with combined anxiety and depression fared worse with respect to disability before and after surgery compared to patients with a single diagnosis or no mental health diagnosis; however, there were no significant differences in recovery ratio or % MCID.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Combined anxiety and depression may predict less improvement in MCS-12 and ODI after lumbar arthrodesis compared with single or no mental health diagnosis.

Impact of Sarcopenia on Degenerative Lumbar Spondylosis

Sarcopenia is characterized by progressive age-related and systematic loss of skeletal muscle mass, strength, and function. It was classified as an independent disease in 2016; thus, there is a sparsity of research on the association of sarcopenia with lower back pain and spinal diseases. Its prevalence is around 10% worldwide and it has been shown to be detrimental to quality of life in the elderly. Sarcopenia can be clinically identified by assessing muscle mass and physical performance measurements to show reduced strength (eg, grip strength chair rise and knee extensions) or function (eg, walking speed or distance). Radiographic imaging techniques such as computed tomography, ultrasound, or magnetic resonance imaging help diagnose sarcopenia in the lumbar spine by measuring either the cross-sectional area or the fatty infiltrate of the lumbar musculature. The presence of sarcopenia in patients preoperatively may lead to worse postoperative outcomes. Research in the treatment options for sarcopenia presurgery is still in its infancy but exercise (both aerobic and resistance exercise have been found to slow down the rate of decline in muscle mass and strength with aging) and nutrition have been utilized to varying success and show great promise in the future.

Patient Outcomes Following Short-segment Lumbar Fusion Are Not Affected by PI-LL Mismatch

STUDY DESIGN

This is a retrospective cohort study.

OBJECTIVE

The objective of this study was to further elucidate the relationship between pelvic incidence-lumbar lordosis (PI-LL) mismatch and surgical outcomes in patients undergoing short segment lumbar fusions for degenerative lumbar disease.

SUMMARY OF BACKGROUND DATA

There are few studies examining the relationship between spinopelvic parameters and patient reported outcome measurements (PROMs) in short segment lumbar degenerative disease.

MATERIALS AND METHODS

A retrospective review was conducted at single academic institution. Patients undergoing 1- or 2-level lumbar fusion were retrospectively identified and separated into 2 groups based on postoperative PI-LL mismatch ≤10 degrees (NM) or PI-LL mismatch >10 degrees (M). Outcomes including the Physical Component Score (PCS)-12, Mental Component Score (MCS)-12, Oswestry Disability Index (ODI), Visual Analog Scale (VAS) back and leg scores were analyzed. Absolute PROM scores, the recovery ratio and the percentage of patients achieving minimum clinically important difference between groups were compared and a multiple linear regression analysis was performed.

RESULTS

A total of 306 patients were included, with 59 patients in the NM group and 247 patients in the M group. Patients in the M group started with a higher degree of PI-LL mismatch compared with the NM group (22.2 vs. 7.6 degrees, P<0.001) and this difference increased postoperatively (24.7 vs. 2.5 degrees, P<0.001). There were no differences between the 2 groups in terms of baseline, postoperative, or Δ outcome scores (P>0.05). In addition, having a PI-LL mismatch was not found to be an independent predictor of any PROM on multivariate analysis (P>0.05).

CONCLUSION

The findings in this study show that even though patients in the M group had a higher degree of mismatch preoperatively and postoperatively, there was no difference in PROMs.

LEVEL OF EVIDENCE

Level III.

Do Preoperative Epidural Steroid Injections Increase the Risk of Infection After Lumbar Spine Surgery?

STUDY DESIGN

Retrospective study.

OBJECTIVE

To elucidate an association between preoperative lumbar epidural corticosteroid injections (ESI) and infection after lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

ESI may provide diagnostic and therapeutic benefit; however, concern exists regarding whether preoperative ESI may increase risk of postoperative infection.

METHODS

Patients who underwent lumbar decompression alone or fusion procedures for radiculopathy or stenosis between 2000 and 2017 with 90 days follow-up were identified by ICD/CPT codes. Each cohort was categorized as no preoperative ESI, less than 30 days, 30 to 90 days, and greater than 90 days before surgery. The primary outcome measure was postoperative infection requiring reoperation within 90 days of index procedure. Demographic information including age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI) was determined. Comparison and regression analysis was performed to determine an association between preoperative ESI exposure, demographics/comorbidities, and postoperative infection.

RESULTS

A total of 15,011 patients were included, 5108 underwent fusion and 9903 decompression only. The infection rate was 1.95% and 0.98%, among fusion and decompression patients, respectively. There was no association between infection and preoperative ESI exposure at any time point (1.0%, P = 0.853), ESI within 30 days (1.37%, P = 0.367), ESI within 30 to 90 days (0.63%, P = 0.257), or ESI > 90 days (1.3%, P = 0.277) before decompression surgery. There was increased risk of infection in those patients undergoing preoperative ESI before fusion compared to those without (2.68% vs. 1.69%, P = 0.025). There was also increased risk of infection with an ESI within 30 days of surgery (5.74%, P = 0.005) and when given > 90 days (2.9%, P = 0.022) before surgery. Regression analysis of all patients demonstrated that fusion (P < 0.001), BMI (P < 0.001), and CCI (P = 0.019) were independent predictors of postoperative infection, while age, sex, and preoperative ESI exposure were not.

CONCLUSION

An increased risk of infection was found in patients with preoperative ESI undergoing fusion procedures, but no increased risk with decompression only. Fusion, BMI, and CCI were predictors of postoperative infection.Level of Evidence: 3.

Regional and experiential differences in surgeon preference for the treatment of cervical facet injuries: a case study survey with the AO Spine Cervical Classification Validation Group

PURPOSE

The management of cervical facet dislocation injuries remains controversial. The main purpose of this investigation was to identify whether a surgeon's geographic location or years in practice influences their preferred management of traumatic cervical facet dislocation injuries.

METHODS

A survey was sent to 272 AO Spine members across all geographic regions and with a variety of practice experience. The survey included clinical case scenarios of cervical facet dislocation injuries and asked responders to select preferences among various diagnostic and management options.

RESULTS

A total of 189 complete responses were received. Over 50% of responding surgeons in each region elected to initiate management of cervical facet dislocation injuries with an MRI, with 6 case exceptions. Overall, there was considerable agreement between American and European responders regarding management of these injuries, with only 3 cases exhibiting a significant difference. Additionally, results also exhibited considerable management agreement between those with ≤ 10 and > 10 years of practice experience, with only 2 case exceptions noted.

CONCLUSION

More than half of responders, regardless of geographical location or practice experience, identified MRI as a screening imaging modality when managing cervical facet dislocation injuries, regardless of the status of the spinal cord and prior to any additional intervention. Additionally, a majority of surgeons would elect an anterior approach for the surgical management of these injuries. The study found overall agreement in management preferences of cervical facet dislocation injuries around the globe.

How Does Smoking Influence Patient-reported Outcomes in Patients After Lumbar Fusion?

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The goal of this study was to determine the effect of smoking on patient-reported outcome measurements (PROMs) after lumbar fusion surgery.

SUMMARY OF BACKGROUND DATA

Although smoking is known to decrease fusion rates after lumbar fusion, there is less evidence regarding the influence of smoking on PROMs after surgery.

METHODS

Patients undergoing between 1 and 3 levels of lumbar fusion were divided into 3 groups on the basis of preoperative smoking status: never smokers (NS); current smokers (CS); and former smokers (FS). PROMs collected for analysis include the Physical Component Score (PCS-12), Mental Component Score (MCS-12), Oswestry Disability Index (ODI), and Visual Analogue Scale back (VAS back) and leg (VAS leg) pain scores. Preoperative and postoperative PROMs were compared between groups. A multiple linear regression analysis was performed to determine whether preoperative smoking status was a predictor of change in PROM scores.

RESULTS

A total of 220 (60.1%) NS, 52 (14.2%) CS, and 94 (25.7%) FS patients were included. Patients in most groups improved within each of the PROMs analyzed (P<0.05). VAS leg pain (P=0.001) was found to significantly differ between groups, with NS and FS having less disability than CS (3.6 vs. 2.0, P=0.010; and 3.6 vs. 2.4, P=0.022; respectively). Being a CS significantly predicted less improvement in ODI (P=0.035), VAS back (P=0.034), and VAS leg (P<0.001) compared with NS. In addition, NS had a significantly lower 30-day readmission rate than CS or FS (3.2% vs. 5.8% and 10.6%, respectively, P=0.029).

CONCLUSION

CS exhibited worse postoperative VAS leg pain and a lower recovery ratio than never smokers. In addition, being in the CS group was a significant predictor of decreased improvement in ODI, VAS back, and VAS leg scores.

LEVEL OF EVIDENCE

Level III.

Does Smoking Status Influence Health-Related Quality of Life Outcome Measures in Patients Undergoing ACDF?

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

Whereas smoking has been shown to affect the fusion rates for patients undergoing an anterior cervical discectomy and fusion (ACDF), the relationship between smoking and health-related quality of life outcome measurements after an ACDF is less clear. The purpose of this study was to evaluate whether smoking negatively affects patient outcomes after an ACDF for cervical degenerative pathology.

METHODS

Patients with tumor, trauma, infection, and previous cervical spine surgery and those with less than a year of follow-up were excluded. Smoking status was assessed by self-reported smoking history. Patient outcomes, including Neck Disability Index, Short Form 12 Mental Component Score, Short Form 12 Physical Component Score (PCS-12), Visual Analogue Scale (VAS) arm pain, VAS neck pain, and pseudarthrosis rates were evaluated. Outcomes were compared between smoking groups using multiple linear and logistic regression, controlling for age, sex, and body mass index (BMI), among other factors. A P value <.05 was considered significant.

RESULTS

A total of 264 patients were included, with a mean follow-up of 19.8 months, age of 53.1 years, and BMI of 29.6 kg/m2. There were 43 current, 69 former, and 152 nonsmokers in the cohort. At baseline, nonsmokers had higher PCS-12 scores than current smokers (P = .010), lower VAS neck pain than current (P = .035) and former (P = .014) smokers, as well as lower VAS arm pain than former smokers (P = .006). Postoperatively, nonsmokers had higher PCS-12 scores than both current (P = .030) and former smokers (P = .035). Smoking status was not a significant predictor of change in patient outcome in multivariate analysis.

CONCLUSIONS

Whereas nonsmokers had higher function and lower pain than former or current smokers preoperatively, smoking status overall was not found to be an independent predictor of outcome scores after ACDF. This supports the notion that smoking status alone should not deter patients from undergoing ACDF for cervical degenerative pathology.

Description and Reliability of the AOSpine Sacral Classification System

BACKGROUND

Several classification systems exist for sacral fractures; however, these systems are primarily descriptive, are not uniformly used, have not been validated, and have not been associated with a treatment algorithm or prognosis. The goal of the present study was to demonstrate the reliability of the AOSpine Sacral Classification System among a group of international spine and trauma surgeons.

METHODS

A total of 38 sacral fractures were reviewed independently by 18 surgeons selected from an expert panel of AOSpine and AOTrauma members. Each case was graded by each surgeon on 2 separate occasions, 4 weeks apart. Intrarater reproducibility and interrater agreement were analyzed with use of the kappa statistic (κ) for fracture severity (i.e., A, B, and C) and fracture subtype (e.g., A1, A2, and A3).

RESULTS

Seventeen reviewers were included in the final analysis, and a total of 1,292 assessments were performed (646 assessments performed twice). Overall intrarater reproducibility was excellent (κ = 0.83) for fracture severity and substantial (κ = 0.71) for all fracture subtypes. When comparing fracture severity, overall interrater agreement was substantial (κ = 0.75), with the highest agreement for type-A fractures (κ = 0.95) and the lowest for type-C fractures (κ = 0.70). Overall interrater agreement was moderate (κ = 0.58) when comparing fracture subtype, with the highest agreement seen for A2 subtypes (κ = 0.81) and the lowest for A1 subtypes (κ = 0.20).

CONCLUSIONS

To our knowledge, the present study is the first to describe the reliability of the AOSpine Sacral Classification System among a worldwide group of expert spine and trauma surgeons, with substantial to excellent intrarater reproducibility and moderate to substantial interrater agreement for the majority of fracture subtypes. These results suggest that this classification system can be reliably applied to sacral injuries, providing an important step toward standardization of treatment.

Update on Spinal Cord Injury Management

The management of acute spinal cord injury requires a multidisciplinary approach to maximize patient outcomes and potential. Treatment of this injury involves both surgical and medical intervention. Medical intervention in acute spinal cord injury is aimed at decreasing the neurotoxic environment that occurs as part of the secondary injury. New neuroregenerative therapies are being developed.

Updated Return-to-Play Recommendations for Collision Athletes After Cervical Spine Injury: A Modified Delphi Consensus Study With the Cervical Spine Research Society

BACKGROUND

Previous studies have attempted to establish return-to-play (RTP) guidelines in collision sport athletes after cervical spine injury; however, recommendations have been limited by scant high-quality evidence and basic consensus survey methodologies.

OBJECTIVE

To create relevant clinical statements regarding management in collision sport athletes after cervical spine injury, and establish consensus RTP recommendations.

METHODS

Following the modified Delphi methodology, a 3 round survey study was conducted with spine surgeons from the Cervical Spine Research Society and National Football League team physicians in order to establish consensus guidelines and develop recommendations for cervical spine injury management in collision sport athletes.

RESULTS

Our study showed strong consensus that asymptomatic athletes without increased magnetic resonance imaging (MRI) T2-signal changes following 1-/2- level anterior cervical discectomy and fusion (ACDF) may RTP, but not after 3-level ACDF (84.4%). Although allowed RTP after 1-/2-level ACDF was noted in various scenarios, the decision was contentious. No consensus RTP for collision athletes after 2-level ACDF was noted. Strong consensus was achieved for RTP in asymptomatic athletes without increased signal changes and spinal canal diameter &gt;10 mm (90.5%), as well as those with resolved MRI signal changes and diameter &gt;13 mm (81.3%). No consensus was achieved in RTP for cases with pseudarthrosis following ACDF. Strong consensus supported a screening MRI before sport participation in athletes with a history of cervical spine injury (78.9%).

CONCLUSION

This study provides modified Delphi process consensus statements regarding cervical spine injury management in collision sport athletes from leading experts in spine surgery, sports injuries, and cervical trauma. Future research should aim to elucidate optimal timelines for RTP, as well as focus on prevention of injuries.

Social Media Presence Correlated with Improved Online Review Scores for Spine Surgeons

BACKGROUND

In the next decade, health care reimbursement will be more aligned to patient clinical outcomes. These outcomes are influenced by the patient's perceived opinion of his or her care. An evaluation into the role of surgeon demographics, social media (SM) accessibility, and office wait times was conducted to identify correlations with these among 3 online review platforms.

METHODS

A total of 206 (148 orthopedic, 58 neurosurgery trained) spine surgeons were included. Spine surgeon ratings and demographics data from 3 physician rating websites (Healthgrades.com [HG], Vitals.com, Google.com [G]) were collected in November 2019. Using the first 10 search results from G we then identified if the surgeons had publicly accessible Facebook, Twitter, or Instagram (IG) accounts.

RESULTS

The mean age of the cohort was 54.3 years (±9.40 years), and 28.2% had one form of publicly accessible SM. Having any SM was significantly correlated with higher scores on HG and G. An IG account was associated with significantly higher scores on all 3 platforms, and having a Facebook account correlated with significantly higher scores on HG in multivariate analysis. An office wait time between 16 and 30 minutes and >30 minutes was associated with worse scores on all 3 platforms (all P < 0.05). An academic practice was associated with higher scores on all 3 platforms (P < 0.05).

CONCLUSIONS

A shorter office wait time and an academic setting practice are associated with higher patient satisfaction scores on all 3 physician review websites. Accessible SM accounts are also associated with higher ratings on physician review websites, particularly IG.

Is the Neck Disability Index an Appropriate Measure for Changes in Physical Function After Surgery for Cervical Spondylotic Myelopathy?

Background

The Neck Disability Index (NDI) is a 10-item questionnaire about symptoms relevant to cervical spine pathology, originally validated in the physical therapy literature. It is unclear if all of the items apply to spine surgery. The purpose of this study was to determine if improvements in the composite NDI score or specific NDI domains are appropriate measures for tracking changes in physical function after surgical intervention for cervical spondylotic myelopathy (CSM).

Methods

A retrospective cohort review of patients treated at a major academic medical center was undertaken. Baseline and postoperative standardized outcome measurement scores, including composite NDI, NDI subdomain, and SF-12 physical component score (PCS), were collected. Wilcoxon signed-rank test was used to determine whether patients exhibited improvement in each of the outcome measures included. Multiple linear regression was performed to determine whether change in NDI composite or subdomain scores predicted change in physical function after surgery for CSM-compared with the well-validated PCS score-controlling for factors such as age, sex, etc.

Results

Baseline data were collected on 118 patients. All outcome measures exhibited significant improvement after surgery based on the Wilcoxon signed-rank test. On linear regression, work (β = -2.419 [-3.831, -1.006]; P = .001) and recreation (β = -1.354 [-2.640, -0.068]; P = .039), as well as the NDI composite score (β = -0.223 [-0.319, -0.127]; P < .001), were significant predictors of change in physical function over time.

Conclusions

Although the NDI composite score did predict change in PCS over time, only 2 of the 10 NDI subdomains were found to be associated with change in physical function over time. Based on these results, the item bank and composite scoring of the NDI are inappropriate for evaluating quality of life in studies of surgically treated cervical spondylotic myelopathy patients.

Clinical Relevance

NDI may not be a valid tool in the determination of physical function changes after surgery for CSM.

Level of Evidence

III.

Proton Pump Inhibitor Use Affects Pseudarthrosis Rates and Influences Patient-Reported Outcomes

STUDY DESIGN

Retrospective cohort review.

OBJECTIVES

Cervical pseudarthrosis is a frequent cause of need for revision anterior cervical discectomy and fusion (ACDF) and may lead to worse patient-reported outcomes. The effect of proton pump inhibitors on cervical fusion rates are unknown. The purpose of this study was to determine if patients taking PPIs have higher rates of nonunion after ACDF.

METHODS

A retrospective cohort review was performed to compare patients who were taking PPIs preoperatively with those not taking PPIs prior to ACDF. Patients younger than 18 years of age, those with less than 1-year follow-up, and those undergoing surgery for trauma, tumor, infection, or revision were excluded. The rates of clinically diagnosed pseudarthrosis and radiographic pseudarthrosis were compared between PPI groups. Patient outcomes, pseudarthrosis rates, and revision rates were compared between PPI groups using either multiple linear or logistic regression analysis, controlling for demographic and operative variables.

RESULTS

Out of 264 patients, 58 patients were in the PPI group and 206 were in the non-PPI group. A total of 23 (8.71%) patients were clinically diagnosed with pseudarthrosis with a significant difference between PPI and non-PPI groups (P = .009). Using multiple linear regression, PPI use was not found to significantly affect any patient-reported outcome measure. However, based on logistic regression, PPI use was found to increase the odds of clinically diagnosed pseudarthrosis (odds ratio 3.552, P = .014). Additionally, clinically diagnosed pseudarthrosis negatively influenced improvement in PCS-12 scores (P = .022).

CONCLUSIONS

PPI use was found to be a significant predictor of clinically diagnosed pseudarthrosis following ACDF surgery. Furthermore, clinically diagnosed pseudarthrosis negatively influenced improvement in PCS-12 scores.

Bromodomain-containing protein 4 inhibition alleviates matrix degradation by enhancing autophagy and suppressing NLRP3 inflammasome activity in NP cells

An imbalance between matrix synthesis and degradation is the hallmark of intervertebral disc degeneration while inflammatory cytokines contribute to the imbalance. Bromodomain and extra-terminal domain (BET) family is associated with the pathogenesis of inflammation, and inhibition of BRD4, a vital member of BET family, plays an anti-inflammatory role in many diseases. However, it remains elusive whether BRD4 plays a similar role in nucleus pulposus (NP) cells and participates in the pathogenesis of intervertebral disc degeneration. The present study aims to observe whether BRD4 inhibition regulates matrix metabolism by controlling autophagy and NLRP3 inflammasome activity. Besides, the relationship was investigated among nuclear factor κB (NF-κB) signaling, autophagy and NLRP3 inflammasome in NP cells. Here, real-time polymerase chain reaction, western blot analysis and adenoviral GFP-LC3 vector transduction in vitro were used, and it was revealed that BRD4 inhibition alleviated the matrix degradation and increased autophagy in the presence or absence of tumor necrosis factor α. Moreover, p65 knockdown or treatment with JQ1 and Bay11-7082 demonstrated that BRD4 inhibition attenuated NLRP3 inflammasome activity through NF-κB signaling, while autophagy inhibition by bafilomycin A1 promoted matrix degradation and NLRP3 inflammasome activity in NP cells. In addition, analysis of BRD4 messenger RNA expression in human NP tissues further verified the destructive function of BRD4. Simply, BRD4 inhibition alleviates matrix degradation by enhancing autophagy and suppressing NLRP3 inflammasome activity through NF-κB signaling in NP cells.

Risk Factors for Pseudarthrosis After Surgical Site Infection of the Spine

Background

Pseudarthrosis following spinal fusion is a complication that frequently requires revision surgery. Reported rates of pseudarthrosis after surgical site infection (SSI) range from 30% to 85%, but few studies have identified infection as an independent risk factor for its development. The purpose of this study was to determine the incidence of clinically symptomatic pseudarthrosis in patient who developed SSI following lumbar fusion and to identify factors associated with its development.

Methods

This was a retrospective review of a prospectively collected database. Patients who underwent spinal surgery and developed SSI between January 2005 and March 2015 with a minimum 2-year follow-up were included. Patient-specific and procedural characteristics were recorded. Presence of pseudarthrosis was determined clinically by the treating surgeon and was confirmed radiographically. All those in the Pseudarthrosis group required a revision procedure after the eradication of infection. Univariate and multivariate analyses were conducted as appropriate.

Results

A total of 416 patients were included. Of these, 21 (5.0%) developed symptomatic pseudarthrosis following SSI. In this cohort, multivariate regression showed that age, Charlson Comorbidity Index, male sex, and surgical approach were not significant predictors of pseudarthrosis formation. However, number of levels fused was found to be the leading predictor for pseudarthrosis development (odds ratio [OR], 1.356/level, P < .001), followed by body mass index (OR, 1.083/point, P < .009) in this cohort. The number of levels fused was found to be a significant predictor of hardware removal (OR, 1.190/level, P < .001). Of the 21 pseudarthrosis cases, 85.7% found staphylococcal species, of which 27.8% exhibited methicillin-resistant Staphylococcus aureus.

Conclusions

The number of spinal levels fused and body mass index are independent predictors of pseudarthrosis in patients who develop SSI after spinal fusion.

Level of Evidence

Level 4.

Clinical Relevance

This is the first known study to specifically identify risk factors for the development of symptomatic pseudarthrosis.

Fusion technique does not affect short-term patient-reported outcomes for lumbar degenerative disease

BACKGROUND/CONTEXT

Degenerative lumbar disease can be addressed via an anterior or posterior approach, and with or without the use of an interbody cage. Although several studies have compared the type of approach and technique, there is a lack of literature assessing patient-reported outcome measures (PROMs) and radiographic parameters between different fusion techniques.

PURPOSE

To determine whether the surgical approach and fusion technique for lumbar degenerative disease had an effect on short-term PROMs and radiographic parameters.

STUDY DESIGN/SETTING

Retrospective Cohort Study.

PATIENT SAMPLE

Three hundred and ninety-one patients who underwent a 1-3 level lumbar spine fusion procedure at a high-volume academic center were retrospectively identified. Patients were divided into three groups based on the type of fusion they underwent: posterolateral fusion (PLF), anterior lumbar interbody fusion (ALIF), or transforaminal lumbar interbody fusion (TLIF).

OUTCOME MEASURES

PROMs: Short Form-12 (SF-12) Physical Component Score (PCS) and Mental Component Score (MCS), Oswestry Disability Index (ODI), Visual Analog Score (VAS) Back, VAS Leg. Spinopelvic measurements: Pelvic Tilt (PT), Sacral Slope (SS), Pelvic Incidence (PI), Lumbar Lordosis (LL), Segmental Lordosis (SL), PI-LL mismatch.

METHODS

Patients with less than 1-year follow-up were excluded from the cohort. Pre- and postoperative spinopelvic measurements were obtained for all patients. Univariate analysis (Chi-squared/Fisher's exact test or ANOVA test with post-hoc Bonferroni test) was used to compare among the three groups in the PROMs and radiographic spinopelvic parameters. Multiple linear regression was used to determine if fusion technique was an independent predictor of change in each patient outcome.

RESULTS

Two hundred and sixteen patients were included in the PLF group, 33 patients in the ALIF group, and 142 patients in the TLIF group. The PLF group was significantly older at baseline (p<.001) and had lower preoperative diagnosis rates of degenerative scoliosis and disc herniations (p<.001), whereas the ALIF group underwent a higher proportion of three-level fusions (p<.001). There was no significant difference in spinopelvic parameters preoperatively, however the ALIF group showed significantly more improvement in SL postoperatively (p=.004) than the PLF and TLIF groups. Within each group, SL improved for the PLF and ALIF groups (p=.002 for both), but not for the TLIF group (p=.238). Comparing patient outcomes, the ALIF group reported lower preoperative VAS Leg scores (p=.031), however, this difference resolved postoperatively. Stratifying for preoperative diagnosis, there were no significant differences in outcomes, except for a greater improvement in VAS Leg scores for degenerative scoliosis patients undergoing ALIF. Using multivariate analysis, fusion technique was not found to be a significant predictor of change in any patient outcome or in odds of revision.

CONCLUSIONS

Lumbar degenerative disease can be treated with several different fusion techniques, however, the relationship between type of fusion and PROMs is not established. Based on the findings in this study, the ALIF group showed greater improvement in SL compared with the PLF and TLIF groups, however, there was no difference noted in overall LL, PI-LL mismatch or other spinopelvic parameters. Despite these radiographic findings, patient outcome measures remained similar between all three fusion types.

Ultrasound-triggered antibiotic release from PEEK clips to prevent spinal fusion infection: Initial evaluations

Despite aggressive peri-operative antibiotic treatments, up to 10% of patients undergoing instrumented spinal surgery develop an infection. Like most implant-associated infections, spinal infections persist through colonization and biofilm formation on spinal instrumentation, which can include metal screws and rods for fixation and an intervertebral cage commonly comprised of polyether ether ketone (PEEK). We have designed a PEEK antibiotic reservoir that would clip to the metal fixation rod and that would achieve slow antibiotic release over several days, followed by a bolus release of antibiotics triggered by ultrasound (US) rupture of a reservoir membrane. We have found using human physiological fluid (synovial fluid), that higher levels (100–500 μg) of vancomycin are required to achieve a marked reduction in adherent bacteria vs. that seen in the common bacterial medium, trypticase soy broth. To achieve these levels of release, we applied a polylactic acid coating to a porous PEEK puck, which exhibited both slow and US-triggered release. This design was further refined to a one-hole or two-hole cylindrical PEEK reservoir that can clip onto a spinal rod for clinical use. Short-term release of high levels of antibiotic (340 ± 168 μg), followed by US-triggered release was measured (7420 ± 2992 μg at 48 h). These levels are sufficient to prevent adhesion of Staphylococcus aureus to implant materials. This study demonstrates the feasibility of an US-mediated antibiotic delivery device, which could be a potent weapon against spinal surgical site infection.

The Effect of Oblique Magnetic Resonance Imaging on Surgical Decision Making for Patients Undergoing an Anterior Cervical Discectomy and Fusion for Cervical Radiculopathy

Background

The purpose of this study was to determine if oblique magnetic resonance imaging (MRI) sequences affect the surgical treatment recommendations for patients with cervical radiculopathy.

Methods

In this cohort study consecutive clinical cases of persistent cervical radiculopathy requiring surgical intervention were randomized, blinded, and reviewed by 6 surgeons. Initially each surgeon recommended treatment based on the history, physical examination, and axial, coronal and sagittal preoperative magnetic resonance (MR) images; when reviewing the cases the second time, the surgeons were provided oblique MR images. This entire process was then repeated after 2 months. Change in surgical recommendation, interobserver and intraobserver reliability and the average number of levels fused was determined.

Results

The addition of the oblique images resulted in the surgical recommendation being altered in 49.2% (59/120) of cases; however, the addition of oblique images did not substantially improve the interobserver reliability of the treatment recommendation (κ = .57 versus.57). Similarly, the overall intraobserver reliability using only traditional MRI sequences (κ = .64) was only slightly improved by the addition of oblique images (κ = .66). Lastly, the addition of oblique images did not change the average number of levels fused (traditional MRI = 1.38, oblique MRI = 1.41, P = .53), or the total number of 3-level fusions recommended (6 versus 6, P = 1.00).

Conclusions

The additional oblique images resulted in a change to the surgical plan in almost 50% of cases; however, it had no substantial effect on the reliability of surgical decision making. Further studies are needed to see if this alteration in treatment affects clinical outcomes.

Level of Evidence

3.

Medicaid Reimbursement for Common Orthopedic Procedures Is Not Consistent

Two major forms of physician reimbursement include Medicare (MCR; federally funded) and Medicaid (MCD; state funded). The only oversight provided to individual states for setting MCD reimbursement is that it must provide a standard payment that does not negatively affect patient care. The goals of this study were to determine the variability of MCD reimbursement for patients who require orthopedic procedures and to assess how this compares with regional MCR reimbursement. Medicaid reimbursement rates from each state were obtained for total knee arthroplasty, total hip arthroplasty, anterior cruciate ligament repair, rotator cuff repair, anterior cervical decompression and fusion, posterior lumbar decompression, carpal tunnel release, distal radius open reduction and internal fixation, proximal femur open reduction and internal fixation, and ankle open reduction and internal fixation. Discrepancy in reimbursement for these procedures and overall differences in MCD vs MCR reimbursement were determined. Average MCD reimbursement was 81.9% of MCR reimbursement. There was significant variation between states (37.7% to 147% of MCR reimbursement for all 10 procedures). Twenty and 40 states provided less than 75% and 100% of MCR reimbursements, respectively. Medicaid valued knee arthroplasty (91.4% of MCR reimbursement) over other common procedures. Conversely, carpal tunnel release (74.1% of MCR reimbursement; P=.004) had the lowest reimbursements. The most interstate variation was noted for anterior cruciate ligament reimbursement, ranging from 20.6% to 229% of local MCR reimbursement. Disparities were found between MCR and MCD when comparing identical procedures. Further research is necessary to understand the impact of these significant differences. It is likely that these discrepancies lead to suboptimal access to necessary orthopedic care. [Orthopedics. 2019; 42(2):e193-e196.].

A Comparison Study of Three Posterior Fixation Strategies in Transforaminal Lumbar Interbody Fusion Lumbar for the Treatment of Degenerative Diseases

BACKGROUND

There are various posterior fixations utilized with transforaminal lumbar interbody fusion (TLIF). Previous studies have focused on the comparison of two fixation techniques.

MATERIALS AND METHODS

Sixty five patients with single-level lumbar disease were included in this retrospective study. Group A was treated by TLIF with bilateral pedicle screw (BPS), Group B treated by TLIF with unilateral pedicle screw (UPS), and Group C treated by TLIF with UPS plus contralateral translaminar facet screw (UPSFS). The operative time, blood loss, Oswestry disability index (ODI), Japanese Orthopaedic Association Scores (JOA), and visual analog scores (VAS) were recorded. Radiographic examination was used to assess fusion rates and incidence of screw failure.

RESULTS

The blood loss and operative times were 188.69 ± 37.69 ml and 132.96.5 ± 8.69 min in BPS group, 117.27 ± 27.11 ml and 99.32 ± 12.94 min in UPS group, and 121.50 ± 22.54 ml and 112.55 ± 9.42 min in UPSFS group; UPS and UPSFS were better than BPS (P < 0.05). The mean followup time was 38.2 months. Fusion rates were - BPS group: 95.6%, UPS group: 90%, UPSFS: 95% (P > 0.05). Screw and/or rod failures were found in three groups (BPS group: 1, UPS group: 2 and UPSFS: 1, P > 0.05). The average postoperative VAS, ODI, and JOA scores of BPS, UPS, and UPSFS were improved significantly in each group compared to preoperative scores (P < 0.05); there were no significant differences between any two groups at each followup time point (P > 0.05).

CONCLUSION

UPSFS with TLIF is a viable treatment option that provides satisfactory clinical results; the clinical outcome and the complication rate were comparable to BPS. In addition, the invasive of UPSFS cases was comparable to UPS and better than BPS cases. For UPS, it could be used in suitable patients.

Clinical Outcomes After Four-Level Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Anterior cervical discectomy and fusion (ACDF) demonstrates reliable improvement in neurologic symptoms associated with anterior compression of the cervical spine. There is a paucity of data on outcomes following 4-level ACDFs. The purpose of this study was to evaluate clinical outcomes for patients undergoing 4-level ACDF.

METHODS

All 4-level ACDFs with at least 1-year clinical follow-up were identified. Clinical outcomes, including fusion rates, neurologic outcomes, and reoperation rates were determined.

RESULTS

Retrospective review of our institutional database revealed 25 patients who underwent 4-level ACDF with at least 1-year clinical follow-up. Average age was 57.5 years (range 38.2-75.0 years); 14 (56%) were male, and average body mass index was 30.2 kg/m² (range 19.9-43.4 kg/m²). Two (8%) required secondary cervical surgery at an average of 94.5 days postoperatively while the remaining 23 did not with an average follow-up of 19 months. Of 23 patients not requiring revision surgery, 16 (69%) patients fused by definition of less than 1 mm of spinous process motion per fused level in flexion and extension. Fifteen (65%) had at least one muscle group with one grade of weakness preoperatively. Nineteen of these patients (83%) had improved to full strength while no patients lost muscle strength.

CONCLUSIONS

Review of our institution's experience demonstrated a low rate of revision cervical surgery for any reason of 8% at mean 19 months follow-up, and neurological examinations consistently improved, despite a high rate of radiographic nonunion (31%).

Severe Lumbar Disability Is Associated With Decreased Psoas Cross-Sectional Area in Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort.

OBJECTIVES

Alterations in lumbar paraspinal muscle cross-sectional area (CSA) may correlate with lumbar pathology. The purpose of this study was to compare paraspinal CSA in patients with degenerative spondylolisthesis and severe lumbar disability to those with mild or moderate lumbar disability, as determined by the Oswestry Disability Index (ODI).

METHODS

We retrospectively reviewed the medical records of 101 patients undergoing lumbar fusion for degenerative spondylolisthesis. Patients were divided into ODI score ≤40 (mild/moderate disability, MMD) and ODI score >40 (severe disability, SD) groups. The total CSA of the psoas and paraspinal muscles were measured on preoperative magnetic resonance imaging (MRI).

RESULTS

There were 37 patients in the SD group and 64 in the MMD group. Average age and body mass index were similar between groups. For the paraspinal muscles, we were unable to demonstrate any significant differences in total CSA between the groups. Psoas muscle CSA was significantly decreased in the SD group compared with the MMD group (1010.08 vs 1178.6 mm², P = .041). Multivariate analysis found that psoas CSA in the upper quartile was significantly protective against severe disability (P = .013).

CONCLUSIONS

We found that patients with severe lumbar disability had no significant differences in posterior lumbar paraspinal CSA when compared with those with mild/moderate disability. However, severely disabled patients had significantly decreased psoas CSA, and larger psoas CSA was strongly protective against severe disability, suggestive of a potential association with psoas atrophy and worsening severity of lumbar pathology.

The local cytokine and growth factor response to recombinant human bone morphogenetic protein-2 (rhBMP-2) after spinal fusion

BACKGROUND CONTEXT

The systemic response regarding cytokine expression after the application of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a rat spinal fusion model has recently been defined, but the local response has not been defined. Defining the local cytokine and growth factor response at the fusion site will help explain the roles of these molecules in the fusion process, as well as that of rhBMP-2. Our hypothesis is that the application of rhBMP-2 to the fusion site will alter the local levels of cytokines and growth factors throughout the fusion process, in a manner that is different from the systemic response, given the tissue-specific effects of rhBMP-2.

PURPOSE

The purpose of this study was to evaluate the local cytokine and growth factor response after the application of rhBMP-2 in a rat spinal fusion model.

STUDY DESIGN/SETTING

This was a basic science animal model study.

METHODS

This study was partially funded by a physician-sponsored grant from Medtronic. A total of 135 Wistar rats (age 8 weeks, weighing approximately 300-400 g) underwent L4-L5 posterolateral intertransverse fusion with demineralized bone graft (approximately 0.4-cm³ rat demineralized bone matrix [DBM] per side). In the first group, 10 µg of rhBMP-2 on an allograft collagen sponge (ACS) was added to the fusion site with approximately 0.4-cm³ rat DBM per side. In the second group, 100 µg of rhBMP-2 on an ACS was added to the fusion site with approximately 0.4-cm³ rat DBM per side, and the third experiment was the control group, which consisted of only an ACS plus 0.4-cm³ DBM per side. There were nine groups of five animals each per experiment. Each group was sacrificed at time points up to 4 weeks (1, 6, 24, and 48 hours, and 4, 7, 14, 21, and 28 days after surgery). At sacrifice, the DBM, transverse processes, and any new bone formed were harvested, immediately frozen in liquid nitrogen, and prepared for protein extraction. ELISA was performed to compare the levels of various cytokines (interleukin [IL]-1β, tumor necrosis factor alpha, IL-6, IL-1RA [IL-1 receptor antagonist], IL-4, and IL-10) and growth factors (vascular endothelial growth factor [VEGF], endothelia growth factor [EGF], insulin-like growth factor-1 [IGF-1], platelet derived growth factor [PDGF], transforming growth factor beta [TGF-β]) that are known to be involved in the fusion-fracture healing process. Fusion was evaluated on the rats sacrificed at 28 days by manual palpation and microcomputed tomography (microCT) by two independent observers.

RESULTS

The expression of cytokines and growth factors varied throughout the fusion process at each time point. In the groups treated with rh-BMP-2, IL-6 and IL-1RA had higher expression in the early time points (1 and 6 hours). Tumor necrosis factor alpha demonstrated significantly lower expression in the groups treated with rhBMP-2 at Days 1, 2, and 4. At the early time points (1 and 6 hours), in the groups treated with rhBMP-2, all of the growth factors IGF-1, VEGF, platelet derived growth factor AB (PDGF-AB), TGF-β had equal or lower expression compared with controls. At 24 hours, there was a peak in IGF-1, VEGF, and PDGF-AB. These growth factors then declined, with IGF-1 and PDGF-AB having a second peak at Day 7. At 4 weeks, all of the rhBMP-2-treated animals fused based on manual palpation and microCT. The control group had four of five rats fused based on manual palpation and two of five rats based on microCT.

CONCLUSIONS

There is significant variability in the expression of cytokines throughout the fusion process after treatment with rhBMP-2. The inflammatory response appears to peak early (1 and 6 hours), followed by a significant decrease with rhBMP-2 treatment. However, the growth factor expression appears to be suppressed early (1 and 6 hours), followed by a peak at 24 hours, and a second peak at Day 7.

Five-year results of a clinical pilot study utilizing a pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis

OBJECTIVE Lumbar spinal stenosis (LSS) is a common condition that leads to significant disability, particularly in the elderly. Current therapeutic options have certain drawbacks. This study evaluates the 5-year clinical and radiographic results of a minimally invasive pedicle-lengthening osteotomy (PLO) for symptomatic LSS. METHODS A prospective, single-arm, clinical pilot study was conducted involving 20 patients (mean age 61.7 years) with symptomatic LSS treated by a PLO procedure at 1 or 2 lumbar levels. All patients had symptoms of neurogenic claudication or radiculopathy secondary to LSS, and had not improved after a minimum 6-month course of nonoperative treatment. Eleven patients had a Meyerding grade I degenerative spondylolisthesis in addition to LSS. Clinical outcomes were measured using the Oswestry Disability Index, Zürich Claudication Questionnaire, 12-Item Short Form Health Survey, and a visual analog scale for back and leg pain. Procedural variables, neurological outcomes, adverse events, and radiological imaging (plain radiographs and CT scans) were collected at the 1.5-, 3-, 6-, 9-, 12-, 24-, and 60-month time points. RESULTS The PLOs were performed through percutaneous incisions, with minimal blood loss in all cases. There were no operative complications. Four adverse events occurred during the follow-up period. Statistically significant improvement was observed in each of the outcome instruments and maintained over the 5-year follow-up period. Imaging studies, reviewed by an independent radiologist, showed no evidence of device subsidence, migration, breakage, or heterotopic ossification. Thin-slice CT scans documented healing of the osteotomy site in all patients at the 6-month time point and an increase of 115% in the mean cross-sectional area of the spinal canal. CONCLUSIONS Treatment of patients with symptomatic LSS with a PLO procedure provided substantial enlargement of the area of the spinal canal and favorable clinical results for both disease-specific and non-disease-specific outcome measures at all follow-up time points out to 5 years. Future research is needed to compare this technique to alternative therapies for LSS.

Stabilization of a thoracolumbar flexion-distraction injury utilizing a temporary interspinous process construct: technical note

Many techniques for fixation in the thoracolumbar spine have been described. Occasionally, particularly during operative management of unstable ligamentous or bony injuries, temporizing fixation may be required. The authors report the case of a patient with a ligamentous thoracolumbar flexion-distraction injury who underwent reduction, posterior instrumentation and fusion, and temporary fixation of the destabilized segment utilizing a novel interspinous process screw/rod construct. This construct was stable after placement and allowed for traditional instrumentation to be placed without causing secondary injury to the spinal cord. To the authors' knowledge, this technique has not previously been described.

Intraoperative pedicle screw navigation does not significantly affect complication rates after spine surgery

Various forms of intraoperative computer-assisted navigation technologies exist, and have consistently been shown to improve pedicle screw accuracy. However, the overall clinical effects of inaccurate pedicle screw placement have been debated. We examined the clinical effects of improved pedicle screw accuracy with computer navigation technology in reducing complication rates in patients undergoing multi-level spinal fusion. We retrospectively reviewed the ACS-NSQIP registry utilizing Current Procedural Terminology (CPT) codes 22843 + 22844 to identify patients undergoing spinal instrumentation of greater than 7 levels, as well as the CPT code 61783 to denote the use of intraoperative computer-assisted navigation. The data were then subdivided to into cohorts consisting of instrumentation cases with and without navigation. Demographic information, as well as intraoperative and postoperative complications, were compared between groups. A total of 3168 patients met our inclusion criteria. There were no statistically significant differences in preoperative population data. Surgical time was significantly longer in the navigation group (391.41 versus 350.3 min), but there were no significant improvements in complication rates with the use of navigation. We found that the mean operative time was significantly increased for patients undergoing spinal instrumentation with computer navigation. This increase in operative time was not associated with any increase in surgical or medical complications. However, in this large series, we were unable to show any clinical benefit to intraoperative navigation, and no reductions in short term complications or rates of return to surgery were observed.

Sacral Fractures and Associated Injuries

STUDY DESIGN

Literature review.

OBJECTIVE

The aim of this review is to describe the injuries associated with sacral fractures and to analyze their impact on patient outcome.

METHODS

A comprehensive narrative review of the literature was performed to identify the injuries associated with sacral fractures.

RESULTS

Sacral fractures are uncommon injuries that result from high-energy trauma, and that, due to their rarity, are frequently underdiagnosed and mistreated. Only 5% of sacral fractures occur in isolation. Injuries most often associated with sacral fractures include neurologic injuries (present in up to 50% of sacral fractures), pelvic ring disruptions, hip and lumbar spine fractures, active pelvic/ abdominal bleeding and the presence of an open fracture or significant soft tissue injury. Diagnosis of pelvic ring fractures and fractures extending to the lumbar spine are key factors for the appropriate management of sacral fractures. Importantly, associated systemic (cranial, thoracic, and abdominopelvic) or musculoskeletal injuries should be promptly assessed and addressed. These associated injuries often dictate the management and eventual outcome of sacral fractures and, therefore, any treatment algorithm should take them into consideration.

CONCLUSIONS

Sacral fractures are complex in nature and often associated with other often-missed injuries. This review summarizes the most relevant associated injuries in sacral fractures and discusses on their appropriate management.

Do Formal Laminectomy and Timing of Decompression for Patients With Sacral Fracture and Neurologic Deficit Affect Outcome?

OBJECTIVES

To identify whether formal sacral decompression provides improvement in outcome for patients with neurologic deficit after sacral fracture compared with patients treated with indirect decompression and whether the timing of surgical decompression influences neurologic outcome?

DATA SOURCES

MEDLINE was searched via PubMed using combinations of the following search terms: "Sacral fracture," "Traumatic Sacral fracture," "Sacral fracture decompression," "Sacral fracture time to decompression," "Sacral Decompression." Only clinical studies on human subjects and in the English language were included.

STUDY SELECTION

Studies that did not provide sufficient detail to confirm the nature of the sacral injury, treatment rendered, and neurologic outcome were excluded. Studies using subjects less than 18 years of age, cadavers, nonhuman subjects, or laboratory simulations were excluded. All other relevant studies were reviewed in detail.

DATA EXTRACTION

All studies were assigned a level of evidence using the grading tool described by the Centre for Evidence-Based Medicine and all studies were analyzed for bias. Both cohorts in articles comparing 2 groups of patients treated differently were included in the appropriate group. Early decompression was defined as before 72 hours.

DATA SYNTHESIS

The effect of decompression technique and timing of decompression surgery on partial and complete neurologic recovery was estimated using a generalized linear mixed model to implement a logistic regression with a study-level random effect.

CONCLUSIONS

There was no benefit to early decompression within 72 hours and no difference between formal laminectomy and indirect decompression with respect to neurologic recovery.

Comparison of occipitocervical and atlantoaxial fusion in treatment of unstable Jefferson fractures

BACKGROUND

Controversy exists regarding the management of unstable Jefferson fractures, with some surgeons performing reduction and immobilization of the patient in a halo vest and others performing open reduction and internal fixation. This study compares the clinical and radiological outcome parameters between posterior atlantoaxial fusion (AAF) and occipitocervical fusion (OCF) constructs in the treatment of the unstable atlas fracture.

MATERIALS AND METHODS

68 consecutive patients with unstable Jefferson fractures treated by AAF or OCF between October 2004 and March 2011 were included in this retrospective evaluation from institutional databases. The authors reviewed medical records and original images. The patients were divided into two surgical groups treated with either AAF (n = 48, F/M 30:18) and OCF (n = 20, F/M 13:7) fusion. Blood loss, operative time, Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score, atlanto-dens interval, lateral mass displacement, complications, and the bone fusion rates were recorded.

RESULTS

Five patients with incomplete paralysis (7.4%) demonstrated postoperative improvement by more than 1 grade on the American Spinal Injury Association impairment scale. The JOA score of the AAF group improved from 12.5 ± 3.6 preoperatively to 15.7 ± 2.3 postoperatively, while the JOA score of the OCF group improved from 11.2 ± 3.3 preoperatively to 14.8 ± 4.2 postoperatively. The VAS score of AAF group decreased from 4.8 ± 1.5 preoperatively to 1.0 ± 0.4 postoperatively, the VAS score of the OCF group decreased from 5.4 ± 2.2 preoperatively to 1.3 ± 0.9 postoperatively.

CONCLUSIONS

The OCF or AAF combined with short-term external immobilization can establish the upper cervical stability and prevent further spinal cord injury and nerve function damage.

Are Modic changes associated with intervertebral disc cytokine profiles?

BACKGROUND CONTEXT

Degenerative changes including Modic changes (MCs) are commonly observed in patients with chronic low back pain. Although intervertebral disc (IVD) cytokine expression has been shown to be associated with low back pain, the cytokine profile for degenerative IVD with and without MC has not been compared.

PURPOSE

This study aimed to evaluate the potential association between IVD cytokine expression and MCs.

STUDY DESIGN

A laboratory study was carried out.

METHODS

The IVD tissue samples from 10 patients with type II MCs and10 patients without MCs who underwent an anterior lumbar interbody and fusion for significant low back pain were collected. The expression levels of 42 cytokines were determined using a RayBio Human Cytokine Antibody Array 3 (RayBiotech Inc, Norcross, GA, USA) and the results were verified with enzyme-linked immunosorbent assay (ELISA).

RESULTS

The cytokine array demonstrated a statistically significant increase in the expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) (p=.001) and epithelial-derived neutrophil-activating peptide 78 (ENA-78) (p=.04), and a trend toward an increase in interleukin-1β (IL-1β) (p=.12) and tumor necrosis factor-α (TNF-α) (p=.22) in IVDs associated with type II MCs. These results were validated with ELISA which demonstrated a 3.85-fold increase in the GM-CSF level between IVDs with type II MCs compared with those without MCs (p=.03). Similarly there was a significant increase in the level of both ENA-78 (3.68-fold, p=.02) and IL-1β (2.11-fold, p=.01) in IVDs with type II MCs. Lastly, there was a trend (p=.07) toward an increase in TNF-α in IVDs with type II MCs (4.4-fold).

CONCLUSION

Intervertebral discs with type II MCs demonstrate a significant increase in IL-1β, GM-CSF, and ENA-78, and there is a trend toward an increase in TNF-α. These results further strengthen the association between MCs and low back pain.

Is It Necessary to Extend a Multilevel Posterior Cervical Decompression and Fusion to the Upper Thoracic Spine?

STUDY DESIGN

A retrospective cohort analysis.

OBJECTIVE

The aim of this study was to determine if there is a difference in the revision rate in patients who undergo a multilevel posterior cervical fusions ending at C7, T1, or T2-T4.

SUMMARY OF BACKGROUND DATA

Multilevel posterior cervical decompression and fusion is a common procedure for patients with cervical spondylotic myelopathy, but there is little literature available to help guide the surgeon in choosing the caudal level of a multilevel posterior cervical fusion.

METHODS

Patients who underwent a three or more level posterior cervical fusion with at least 1 year of clinical follow-up were identified. Patients were separated into three groups on the basis of the caudal level of the fusion, C7, T1, or T2-T4, and the revision rate was determined. In addition, the C2-C7 lordosis and the C2-C7 sagittal vertical axis (SVA) was recorded for patients with adequate radiographic follow-up at 1 year.

RESULTS

The overall revision rate was 27.8% (61/219 patients); a significant difference in the revision rates was identified between fusions terminating at C7, T1, and T2-T4 (35.3%, 18.3%, and 40.0%, P = 0.008). When additional variables were taken into account utilizing multivariate linear regression modeling, patients whose construct terminated at C7 were 2.29 (1.16-4.61) times more likely to require a revision than patients whose construct terminated at T1 (P = 0.02), but no difference between stopping at T1 and T2-T4 was identified.

CONCLUSION

Multilevel posterior cervical fusions should be extended to T1, as stopping a long construct at C7 increases the rate of revision.

LEVEL OF EVIDENCE

3.

The Development of a Universally Accepted Sacral Fracture Classification: A Survey of AOSpine and AOTrauma Members

Study Design Survey study. Objective To determine the global perspective on controversial aspects of sacral fracture classifications. Methods While developing the AOSpine Sacral Injury Classification System, a survey was sent to all members of AOSpine and AOTrauma. The survey asked four yes-or-no questions to help determine the best way to handle controversial aspects of sacral fractures in future classifications. Chi-square tests were initially used to compare surgeons' answers to the four key questions of the survey, and then the data was modeled through multivariable logistic regression analysis. Results A total of 474 surgeons answered all questions in the survey. Overall 86.9% of respondents felt that the proposed hierarchical nature of injuries was appropriate, and 77.8% of respondents agreed that that the risk of neurologic injury is highest in a vertical fracture through the foramen. Almost 80% of respondents felt that the separation of injuries based on the integrity of L5-S1 facet was appropriate, and 83.8% of surgeons agreed that a nondisplaced sacral U fracture is a clinically relevant entity. Conclusion This study determines the global perspective on controversial areas in the injury patterns of sacral fractures and demonstrates that the development of a comprehensive and universally accepted sacral classification is possible.

Bone substitutes and expanders in Spine Surgery: A review of their fusion efficacies

STUDY DESIGN

A narrative review of literature.

OBJECTIVE

This manuscript intends to provide a review of clinically relevant bone substitutes and bone expanders for spinal surgery in terms of efficacy and associated clinical outcomes, as reported in contemporary spine literature.

SUMMARY OF BACKGROUND DATA

Ever since the introduction of allograft as a substitute for autologous bone in spinal surgery, a sea of literature has surfaced, evaluating both established and newly emerging fusion alternatives. An understanding of the available fusion options and an organized evidence-based approach to their use in spine surgery is essential for achieving optimal results.

METHODS

A Medline search of English language literature published through March 2016 discussing bone graft substitutes and fusion extenders was performed. All clinical studies reporting radiological and/or patient outcomes following the use of bone substitutes were reviewed under the broad categories of Allografts, Demineralized Bone Matrices (DBM), Ceramics, Bone Morphogenic proteins (BMPs), Autologous growth factors (AGFs), Stem cell products and Synthetic Peptides. These were further grouped depending on their application in lumbar and cervical spine surgeries, deformity correction or other miscellaneous procedures viz. trauma, infection or tumors; wherever data was forthcoming. Studies in animal populations and experimental in vitro studies were excluded. Primary endpoints were radiological fusion rates and successful clinical outcomes.

RESULTS

A total of 181 clinical studies were found suitable to be included in the review. More than a third of the published articles (62 studies, 34.25%) focused on BMP. Ceramics (40 studies) and Allografts (39 studies) were the other two highly published groups of bone substitutes. Highest radiographic fusion rates were observed with BMPs, followed by allograft and DBM. There were no significant differences in the reported clinical outcomes across all classes of bone substitutes.

CONCLUSIONS

There is a clear publication bias in the literature, mostly favoring BMP. Based on the available data, BMP is however associated with the highest radiographic fusion rate. Allograft is also very well corroborated in the literature. The use of DBM as a bone expander to augment autograft is supported, especially in the lumbar spine. Ceramics are also utilized as bone graft extenders and results are generally supportive, although limited. The use of autologous growth factors is not substantiated at this time. Cell matrix or stem cell-based products and the synthetic peptides have inadequate data. More comparative studies are needed to evaluate the efficacy of bone graft substitutes overall.

Genetic aspects of intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) is one of the common causes of low back pain. Similar to many other multifactorial diseases, it is affected by environmental and genetic factors. Although not completely understood, genetic factors include a wide spectrum of variations, such as single nucleotide polymorphisms, which could play a significant role in the etiology of this disease. Besides, the interactions with environmental factors could make the role of genetic factors more complicated. Genetic variations in disc components could participate in developing degenerative disc disease through altering the normal homeostasis of discs. Gene polymorphisms in disc proteins (collagens I, II, III, IX, and XI), proteoglycans (aggrecan), cytokines (interleukins I, VI, and X), enzymes (matrix metalloproteinases II, III, and IX), and vitamin D receptor seem to play considerable roles in the pathology of this disease. There are also many other investigated genes that could somehow take part in the process. However, it seems that more studies are needed to clarify the exact role of genetics in IVDD.

Comparing the Treatment Algorithm and Complications for Patients Undergoing an Anterior Cervical Discectomy and Fusion at a Physician-Owned Specialty Hospital and a University-Owned Tertiary Care Hospital

The purpose of this case-control study is to compare the treatment algorithm and complication rate for patients who undergo an anterior cervical discectomy and fusion at a physician-owned specialty hospital to those who undergo surgery at a university-owned tertiary care hospital. Two controls were identified for 77 patients, and no differences in demographic data were identified. The median time between the onset of symptoms and surgery was shorter for patients who had surgery at the tertiary care center than for patients who had surgery at the specialty hospital (26.7 weeks vs 32.7 weeks, P = .0004). Furthermore, a higher percentage of patients who had surgery at the specialty hospital attempted nonoperative treatments than patients who underwent surgery at the tertiary care hospital.

A Systematic Review of the Treatment of Geriatric Type II Odontoid Fractures

BACKGROUND

Odontoid fractures are the most common cervical spine fracture in the geriatric population; however, the treatment of type II odontoid fractures in this age group is controversial.

OBJECTIVE

To compare the short-term (<3 months) mortality, long-term (≥12 months) mortality, and complication rates of patients >60 years of age with a type II odontoid fracture managed either operatively or nonoperatively.

METHODS

We performed a systematic review of literature published between January 1, 2000, and February 1, 2015, related to the treatment of type II odontoid fractures in patients >60 years of age. An analysis of short-term mortality, long-term mortality, and the occurrence of complications was performed.

RESULTS

A total of 452 articles were identified, of which 21 articles with 1233 patients met the inclusion criteria. Short-term mortality (odds ratio, 0.43; 95% confidence interval, 0.30-0.63) and long-term mortality (odds ratio, 0.47; 95% confidence interval, 0.34-0.64) were lower in patients who underwent surgical treatment than in those who had nonsurgical treatment, and there were no significant differences in the rate of complications (odds ratio, 1.01; 95% confidence interval, 0.63-1.63). Surgical approach (posterior vs anterior) showed no significant difference in mortality or complication rate. Similarly, no difference in mortality or complication rate was identified with hard collar or a halo orthosis immobilization.

CONCLUSION

The current literature suggests that well-selected patients >60 years of age undergoing surgical treatment for a type II odontoid fracture have a decreased risk of short-term and long-term mortality without an increase in the risk of complications.

The Thoracolumbar AOSpine Injury Score

Study Design Survey of 100 worldwide spine surgeons. Objective To develop a spine injury score for the AOSpine Thoracolumbar Spine Injury Classification System. Methods Each respondent was asked to numerically grade the severity of each variable of the AOSpine Thoracolumbar Spine Injury Classification System. Using the results, as well as limited input from the AOSpine Trauma Knowledge Forum, the Thoracolumbar AOSpine Injury Score was developed. Results Beginning with 1 point for A1, groups A, B, and C were consecutively awarded an additional point (A1, 1 point; A2, 2 points; A3, 3 points); however, because of a significant increase in the severity between A3 and A4 and because the severity of A4 and B1 was similar, both A4 and B1 were awarded 5 points. An uneven stepwise increase in severity moving from N0 to N4, with a substantial increase in severity between N2 (nerve root injury with radicular symptoms) and N3 (incomplete spinal cord injury) injuries, was identified. Hence, each grade of neurologic injury was progressively given an additional point starting with 0 points for N0, and the substantial difference in severity between N2 and N3 injuries was recognized by elevating N3 to 4 points. Finally, 1 point was awarded to the M1 modifier (indeterminate posterolateral ligamentous complex injury). Conclusion The Thoracolumbar AOSpine Injury Score is an easy-to-use, data-driven metric that will allow for the development of a surgical algorithm to accompany the AOSpine Thoracolumbar Spine Injury Classification System.

The effect of increased T2 signal intensity in the spinal cord on the injury severity and early neurological recovery in patients with central cord syndrome

OBJECTIVE

The aim of this paper was to compare the severity of the initial neurological injury as well as the early changes in the American Spinal Injury Association (ASIA) motor score (AMS) between central cord syndrome (CCS) patients with and without an increased T2 signal intensity in their spinal cord.

METHODS

Patients with CCS were identified and stratified based on the presence of increased T2 signal intensity in their spinal cord. The severity of the initial neurological injury and the progression of the neurological injury over the 1st week were measured according to the patient's AMS. The effect of age, sex, congenital stenosis, surgery within 24 hours, and surgery in the initial hospitalization on the change in AMS was determined using an analysis of variance.

RESULTS

Patients with increased signal intensity had a more severe initial neurological injury (AMS 57.6 vs 75.3, respectively, p = 0.01). However, the change in AMS over the 1st week was less severe in patients with an increase in T2 signal intensity (−0.85 vs −4.3, p = 0.07). Analysis of variance did not find that age, sex, Injury Severity Score, congenital stenosis, surgery within 24 hours, or surgery during the initial hospitalization affected the change in AMS.

CONCLUSIONS

The neurological injury is different between patients with and without an increased T2 signal intensity. Patients with an increased T2 signal intensity are likely to have a more severe initial neurological deficit but will have relatively minimal early neurological deterioration. Comparatively, patients without an increase in the T2 signal intensity will likely have a less severe initial injury but can expect to have a slight decline in neurological function in the 1st week.

Diagnosis and neurologic status as predictors of surgical site infection in primary cervical spinal surgery

BACKGROUND CONTEXT

Surgical site infection (SSI) incidence after cervical spinal surgery ranges from 0.1% to 17%. Although the general risk factors for SSI have been discussed, the relationship of neurologic status and trauma to SSI has not been explicitly explored.

PURPOSE

This study aimed to study associated risk factors and to report the incidence of SSI in patients who have undergone cervical spinal surgery with the following four preoperative diagnoses: (1) degenerative disease with no myelopathy (MP), (2) degenerative disease with MP, (3) traumatic cervical injury without spinal cord injury (SCI), (4) traumatic cervical injury with SCI. We hypothesize that SSI incidence would increase from Group (1) to Group (4).

STUDY DESIGN

Retrospective database analysis was carried out.

PATIENTS SAMPLE

We used International Classification of Diseases codes to identify the four groups of patients in the U.S. Nationwide Inpatient Sample (NIS) from the years 2000 to 2011. We complemented this study with a similar search in our institutional database (ID) from the years 2000 to 2013. Patients with concomitant congenital deformity, infection, inflammatory disease, and neoplasia were excluded, as were revision surgeries.

OUTCOME MEASURES

The primary outcome studied was the occurrence of SSI. Statistical analyses included bivariate comparisons and chi-square distribution of demographic data and multivariable regression for demographic, surgical, and outcome variables.

RESULTS

A total of 1,247,281 and 5,540 patients met inclusion criteria in the NIS database and the ID, respectively. Overall SSI incidence was 0.73% (NIS) versus 1.75% (ID). Surgical site infection incidence increased steadily from 0.52% in Group (1) to 1.97% in Group (4) in the NIS data and from 0.88% to 5.54% in the ID. Differences between diagnostic groups and cohorts reached statistical significance. Surgical site infection was predicted significantly by status (odds ratio [OR] 1.69, p<.0001) and trauma (OR 1.30, p=.0003) in the NIS data. Other significant predictors included the following: approach, number of levels fused, female gender, black race, medium size hospital, rural hospital, large hospital, western US hospital and Medicare coverage. In the ID, only trauma (OR 2.11, p=.03) reached significance when accounting for comorbidities.

CONCLUSIONS

Both primary diagnosis (trauma vs. degenerative) and neurologic status (MP or SCI) were found to be strong and independent predictors of SSI in cervical spine surgery.

Pelvic Incidence in Patients with Hip Osteoarthritis

BACKGROUND

Hip osteoarthritis (OA) is a major cause of pain and disability that results in considerable social and medical costs. Mechanics such as posture, alignment and orientation of the hips and the spinal column and the relationship between these factors have been implicated in the development of both hip and spine pathologies. This study aims to test the hypothesis if pelvic incidence varies in patients with and without osteoarthritis. We assessed the relationship between spinopelvic alignment as measured by pelvic incidence (PI) and the presence of hip OA.

METHODS

We collected supine pelvis CT scans of 1,012 consecutive patients not known to have hip OA. Our first group consisted of 95 patients with moderate to severe hip OA as per radiology reports. The second group included 87 patients with no evidence of hip OA. Power analysis revealed the need for 77 patients per group to find a mean difference in PI of 5° or less between both groups. Two trained physicians independently measured the PI to account for inter-observer reliability.

RESULTS

Patients with moderate to severe hip OA had a mean PI of 56.5°±12.8°. The mean PI for patients without hip OA was 57.2°±7.5°. An independent samples t-test revealed no significant difference between the PI values of the two groups. Spearman's correlation coefficient of 0.754 demonstrated a high inter-observer reliability.

CONCLUSION

There was no difference in PI angle of hip OA patients and "healthy" patients. Our measurements of patients without OA were almost identical to the reported normal PI values in the literature. It appears that hip OA is not associated with PI angle, refuting the hypothesis made in previous studies, stating that elevated PI contributes to the future development of hip arthritis. CT scan seems to be a reliable and accurate way of assessing pelvic incidence.

Treatment of isolated cervical facet fractures: a systematic review

OBJECT

In this clinically based systematic review of cervical facet fractures, the authors’ aim was to determine the optimal clinical care for patients with isolated fractures of the cervical facets through a systematic review.

METHODS

A systematic review of nonoperative and operative treatment methods of cervical facet fractures was performed. Reduction and stabilization treatments were compared, and analysis of postoperative outcomes was performed. MEDLINE and Scopus databases were used. This work was supported through support received from the Association for Collaborative Spine Research and AOSpine North America.

RESULTS

Eleven studies with 368 patients met the inclusion criteria. Forty-six patients had bilateral isolated cervical facet fractures and 322 had unilateral isolated cervical facet fractures. Closed reduction was successful in 56.4% (39 patients) and 63.8% (94 patients) of patients using a halo vest and Gardner-Wells tongs, respectively. Comparatively, open reduction was successful in 94.9% of patients (successful reduction of open to closed reduction OR 12.8 [95% CI 6.1–26.9], p < 0.0001); 183 patients underwent internal fixation, with an 87.2% success rate in maintaining anatomical alignment. When comparing the success of patients who underwent anterior versus posterior procedures, anterior approaches showed a 90.5% rate of maintenance of reduction, compared with a 75.6% rate for the posterior approach (anterior vs posterior OR 3.1 [95% CI 1.0–9.4], p = 0.05).

CONCLUSIONS

In comparison with nonoperative treatments, operative treatments provided a more successful outcome in terms of failure of treatment to maintain reduction for patients with cervical facet fractures. Operative treatment appears to provide superior results to the nonoperative treatments assessed.

[The AOSpine Classification of Thoraco-Lumbar Spine Injuries]

Optimal treatment of injuries to the thoracolumbar spine is based on a detailed analysis of instability, as indicated by injury morphology and neurological status, together with significant modifying factors. A classification system helps to structure this analysis and should also provide guidance for treatment. Existing classification systems, such as the Magerl classification, are complex and do not include the neurological status, while the TLICS system has been accused of over-simplifying the influence of fracture morphology and instability. The AOSpine classification group has developed a new classification system, based mainly upon the Magerl and TLICS classifications, and with the aim of overcoming these drawbacks. This differentiates three main types of injury: Type A lesions are compression lesions to the anterior column; Type B lesions are distraction lesions of either the anterior or the posterior column; Type C lesions are translationally unstable lesions. Type A and B lesions are split into subgroups. The neurological damage is graded in 5 steps, ranging from a transient neurological deficit to complete spinal cord injury. Additional modifiers describe disorders which affect treatment strategy, such as osteoporosis or ankylosing diseases. Evaluations of intra- and inter-observer reliability have been very promising and encourage the introduction of this AOSpine classification of thoracolumbar injuries to the German speaking community.

Is there a regional difference in morphology interpretation of A3 and A4 fractures among different cultures?

OBJECT The aim of this study was to determine if the ability of a surgeon to correctly classify A3 (burst fractures with a single endplate involved) and A4 (burst fractures with both endplates involved) fractures is affected by either the region or the experience of the surgeon. METHODS A survey was sent to 100 AOSpine members from all 6 AO regions of the world (North America, South America, Europe, Africa, Asia, and the Middle East) who had no prior knowledge of the new AOSpine Thoracolumbar Spine Injury Classification System. Respondents were asked to classify 25 cases, including 6 thoracolumbar burst fractures (A3 or A4). This study focuses on the effect of region and experience on surgeons' ability to properly classify these 2 controversial fracture variants. RESULTS All 100 surveyed surgeons completed the survey, and no significant regional (p > 0.50) or experiential (p > 0.21) variability in the ability to correctly classify burst fractures was identified; however, surgeons from all regions and with all levels of experience were more likely to correctly classify A3 fractures than A4 fractures (p < 0.01). Further analysis demonstrated that no region predisposed surgeons to increasing their assessment of severity of burst fractures. CONCLUSIONS A3 and A4 fractures are the most difficult 2 fractures to correctly classify, but this is not affected by the region or experience of the surgeon; therefore, regional variations in the treatment of thoracolumbar burst fractures (A3 and A4) is not due to differing radiographic interpretation of the fractures.