Faculty Bibliography

BACKGROUND CONTEXT: Numerous studies have demonstrated poorer outcomes in patients with Workers' Compensation (WC) when compared to those without WC following treatment of various of health conditions including spine disorders. It is thus important to consider compensation status when assessing treatment outcomes in spine surgery. However, reported strengths of association have varied significantly (1.31-7.22). PURPOSE: The objective of this study was to evaluate the association of unsatisfactory outcomes on compensation status in spine surgery patients. STUDY DESIGN/SETTING: Meta-analysis PATIENT SAMPLE: Not applicable OUTCOME MEASURE: Demographics, type of surgery, country, follow-up time, patient satisfaction, return to work and non-union events. METHODS: Both prospective and retrospective studies that compared outcomes between compensated and non-compensated patients in spine surgery were included. Two independent investigators extracted outcome data. The meta-analysis was performed using Revman software. Random effects model was used to calculate risk ratio (RR, 95% confidence interval (CI) for dichotomous variables. There are no conflicts of interest to report among the authors, and no funding was received for this study. RESULTS: 31 studies (13 prospective; 18 retrospective) with a total of 3567 patients were included in the analysis. Follow-up time varied from 4 months to 10 years. 12 studies involved only decompression; the rest were fusion. Overall RR of an unsatisfactory outcome was 2.12 [1.74, 2.58; p<0.001] in patients with WC when compared to those without WC after surgery. RR of an unsatisfactory outcome in patients with WC, compared to those without, was 2.09 [1.38, 3.17]; p<0.01 among studies from Europe and Australia and 2.14 [1.48, 2.60]; p<0.01 among US studies. RR of decompression-only procedures was 2.53 [1.85, 3.47]; p<0.01 and 1.79 [1.45, 2.21]; p<0.01 for fusion. 43% (209/491) of patients with WC returned to work versus 17% (214/1250) of those without WC (RR 2.07 [1.43, 2.98]; p<0.001). 25 % (74/292) and 13.5% (39/287) of patients had non-union in the compensated and non-compensated groups, respectively. This was not statistically significant (RR 1.33 [0.92, 1.91]; p=0.07). CONCLUSIONS: Workers' compensation patients have a two-fold increased risk of an unsatisfactory outcome compared to non-compensated patients after surgery. This association was consistent when studies were grouped by country or procedure. Compensation status must be considered in all surgical intervention studies.

BACKGROUND: Wound drains that are left in place for a prolonged period of time have a higher rate of bacterial contamination. Following spinal surgery, a drain is often left in place for a longer period of time if it maintains a high output. Given the major consequences of an infection following spinal surgery and the lack of data with regard to the use of antibiotics and drains, we performed a study of patients with a drain following spinal surgery to compare infection rates between those who were treated with antibiotics for twenty-four hours and those who received antibiotics for the duration for which the drain was in place. METHODS: We performed a prospective randomized trial of 314 patients who underwent multilevel thoracolumbar spinal surgery followed by use of a postoperative drain. The patients were randomized into two groups, one of which received perioperative antibiotics for twenty-four hours (twenty-four-hour group) and the other of which received antibiotics for the duration that the drain was in place (drain-duration group). Data collected included demographic characteristics, medical comorbidities, type of spinal surgery, and surgical site infection. RESULTS: Twenty-one (12.4%) of the 170 patients in the twenty-four-hour group and nineteen (13.2%) of the 144 in the drain-duration group developed a surgical site infection (p = 0.48). There were no significant differences between the twenty-four-hour and drain-duration groups with respect to demographic characteristics (except for the American Society of Anesthesiologists [ASA] classification), operative time, type of surgery, drain output, or length of hospital stay. CONCLUSIONS: Continuing perioperative administration of antibiotics for the entire duration that a drain is in place after spinal surgery did not decrease the rate of surgical site infections. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Introduction ProDisc-C (Synthes Spine USA Products; LLC, West Chester, PA) began its FDA Investigational Device Exemption multicenter randomized study in 2003 and has received marketing approval by the FDA in 2007. This study reports final results of the 7-year follow-up. The aim of this study is to compare long-term efficacy and safety of single-level cervical arthroplasty using ProDisc-C (DePuy-Synthes, Inc) to anterior cervical discectomy and fusion (ACDF) in patients with symptomatic cervical disk disease. Materials and Methods Between August 2003 and January 2005, 209 patients with symptomatic single-level cervical degenerative disk disease refractory to conservative management were enrolled in a prospective, randomized, controlled trial. Of these, 103 received ProDisc-C and 106 ACDF. Patients were followed up for 7 years. The outcomes included Visual Analog Scale for Arm and Neck Pain, Neck Disability Index (NDI), MOS-Short Form 36 (MOS-SF36), neurologic success, adverse events related to the surgery, and secondary surgeries. At the final follow-up at 7 years, the overall follow-up rate was 79.0%. Statistical Analysis Discrepancies between the groups in preoperative demographics and postoperative outcome valuations were analyzed using the Fisher exact test for the categorical variables, and the t-test for the continuous variables. The changes in outcome scores at 2 and 7 years were analyzed using two-way repeated measurements analysis of covariance (ANCOVA) with one fixed factor ("GROUP") (ACDF and ProDisc-C), one repeated factor ("TIME") with two levels corresponding to two follow-up times (2 and 7 years), as well as the interaction effect between the GROUP and the TIME factors. Differences in proportions of secondary operations on the index surgical levels were analyzed by Fisher exact test. In the case of multiple secondary surgeries, each subject was counted only once. The time until the secondary surgery was analyzed by Kaplan-Meyer survival estimates, and the differences in survival tested by log-rank test. Results Table 1 shows adjusted means and their confidence intervals by treatment group. All outcomes improved compared with preoperative status in both study arms at 2 years (p < 0.05), except for the SF36 General Health (p > 0.05). At 7 years postoperative, the improvements were maintained for the same variables as at 2 years postoperative (p < 0.05). There were no significant differences between the ACDF and ProDisc-C patients in the extent of the improvement (GROUP effect p > 0.05 for all variables) for any outcome variable. Further, there were no differences in the extent of improvement between 2 and 7 years postoperative (TIME effect p > 0.05) for all outcome variables. Finally, there were no differences in the time course changes by the group at 2 and 7 years (GROUP*TIME interaction p > 0.05) for any outcome variable. Neurological success rate at 2 years was 88.0 and 90.9% in the ACDF and ProDisc-C groups, respectively (p > 0.05). At 7 years, the success rate was 88.9 and 87.7%, in the ACDF and ProDisc-C groups, respectively (p > 0.05). At 7 years postoperatively, 11.3% subjects in ProDisc-C group had evidence of bone bridging at index level. Of the 106 subjects in the ACDF group, 16 (15.1%) subjects required a secondary operation at the same level compared with 6 out of 103 (5.8%) in the ProDisk-C group (p = 0.0410). Of six secondary surgeries in the ProDisc-C group, three were for device removal, one for reoperation, and two for revision. In the ACDF group, there were six removals, one reoperation, nine revisions, and three supplemental fixations. The reoperation-free survival time was better in the Pro-Disc-C compared with ACDF patients (log-rank p = 0.0221). The conditional incidence rate ratio for the secondary surgery was 3.09 (95% CI, 1.27-8.45, p = 0.0112). There were 6 surgeries in 6 subjects that involved adjacent levels in the ProDisc-C group, compared with 22 surgeries in 13 subjects in the ACDF group. The p-value for the subjects with any surgery at the adjacent level was 0.1134 and the p-value for surgery events was 0.0029 Conclusion Both ACDF and cervical arthroplasty with ProDisc-Care associated with significant long-term improvement in relevant symptoms, functional and health-related quality of life outcomes. There is no evidence of differential efficacy between the two treatments. Disc arthroplasty with ProDisc-C is associated with a significantly lower risk of secondary operation at both the index and adjacent surgical levels

Objective. The purpose of this study was to evaluate a new questionnaire to assess outcomes related to the midline anterior lumbar approach and to identify risk factors for negative patient responses. Methods. A retrospective review of 58 patients who underwent anterior lumbar surgery at a single institution for either degenerative disc disease or spondylolisthesis in 2009 was performed. The outcome measures included our newly developed Anterior Lumbar Surgery Questionnaire (ALSQ), ODI, and EQ-5D. Results. There were 58 patients available for followup, 27 women and 31 men. The average age at surgery was 50.8 years, with an average followup of 2.92 years. The average change in ODI was 34.94 (22.7) and EQ-5D was 0.28 (0.29). The rate of complications with the anterior approach was 10.3% and there was one male patient (3.2%) with retrograde ejaculation. Determination of the effectiveness of the new ALSQ revealed that it significantly correlated to the EQ-5D and ODI (P < 0.05). Smoking was associated with a negative response on thirteen questions. BMP use was not associated with a negative response on any sexual function questions. Conclusions. Our new Anterior Lumbar Surgery Questionnaire determines patient perceived complications related to the midline anterior lumbar surgical approach.

BACKGROUND CONTEXT: Comparative effectiveness as well as cost analysis research are gaining popularity within the field of spinal surgery. In general, prior studies have shown that surgical interventions with a cost per Quality Adjusted Life Year (QALY) less than >=100,000 are cost-effective for our society. Cost-effectiveness studies for surgical management of spondylolisthesis are lacking. PURPOSE: The purpose of this study is to determine the cost/QALYof lumbar spondylolisthesis treated with multiple surgical techniques, and to identify preoperative factors that lead to cost-effectiveness at 2-year follow-up. STUDY DESIGN/SETTING: Retrospective analysis of prospectively collected data. PATIENT SAMPLE: Patients who underwent surgery for degenerative or isthmic spondylolisthesis at a single institution from 2009-2011. OUTCOME MEASURES: Oswestry Disability Index, change in QALY, cost/QALY. METHODS: We performed a retrospective analysis of prospectively collected data on 44 patients who underwent surgery for degenerative or isthmic spondylolisthesis. There were 30 cases of degenerative and 14 cases of isthmic spondylolisthesis. There were 27 women and 17 men, with an average age at surgery of 59.7 years old (SD 14.8). The change in QALY was determined from the 2-year outcome scores using EuroQol-5D. Outcomes were also assessed using the Oswestry Disability Index (ODI). Hospital DRG codes were used to assess Medicare based hospital costs. Surgical, neuromonitoring, and anesthesia CPT codes were used to determine additional direct care costs of surgery. Analysis was performed to determine which factors were associated with a cost/QALY less than >=100,000, thereby making the procedure cost-effective. Statistical analysis was performed using ANOVA, Chi Square, and linear regression analysis. RESULTS: The average length of follow up was 2 years (SD 0.82). The average postoperative improvement in ODI was 24.5 (SD 23.9) and change in QALYwas 0.4449 (SD 0.2984). The average cost/QALYat 2-year follow-up !

PURPOSE. To measure anatomic variations of the lumbar plexus within the psoas in relation to the L2/3, L3/4, and L4/5 disc spaces and to delineate a safe zone to avoid nerve injury during retractor placement via the transpsoas approach. METHODS. Six male and 6 female cadavers (24 psoas/ lumbar plexuses) aged 35 to 74 years were dissected. The lumbar plexus was isolated bilaterally. The L2, L3, and L4 nerve roots were identified and isolated without disturbing their natural anatomic course. The anteroposterior (AP) diameter of each intervertebral disc at L2/3, L3/4, and L4/5 was used as a reference. Four measurements were made using a caliper: the AP and mediolateral (ML) diameters of the psoas and AP and ML excursions of each nerve root. Percentages were calculated for the 4 measurements using the reference of the AP diameter of the intervertebral disc at each level. Comparison between left and right sides, between males and females, and between excursions of nerve roots were made. RESULTS. The AP diameter of the psoas increased from L2 to L4, with a mean vertebral body coverage of 80%, 86%, and 85% at L2/3, L3/4, and L4/5, respectively. Both the L2 and L3 nerve roots demonstrated substantial anterior trajectories as they coursed distally in the lumbar spine. No nerve root encroached anteriorly beyond 33% of the intervertebral disc space at L2 to L5. CONCLUSION. The lumbar plexus area corresponding to the anterior half of the intervertebral disc was the safe zone. Procedures to the lumbar spine via the transpsoas approach should be performed within the safe zone to avoid nerve injury.

STUDY DESIGN.: Randomized controlled trial. OBJECTIVE.: Analyze the clinical outcomes at 5 years comparing cervical total disc replacement (TDR) with ProDisc-C (Synthes Spine USA Products; LLC, West Chester, PA) with anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA.: Previous reports of 2- and 4-year results have shown that ProDisc-C, a TDR for surgical treatment of patients experiencing single-level symptomatic cervical disc disease between C3 and C7, is safe and effective. METHODS.: Two hundred nine patients (103 ProDisc-C and 106 ACDF) from 13 sites were randomized and treated. Results including neck disability index, visual analog scale (VAS) neck and arm pain, Short Form-36 (SF-36), neurological examination, device success, adverse event occurrence, and VAS patient satisfaction were analyzed. RESULTS.: Demographics were similar between the 2 patient groups (ProDisc-C: 42.1 +/- 8.4 yr, 44.7% males; ACDF: 43.5 +/- 7.1 yr, 46.2% males). Rates of follow-up at 2 years were 98.1% ProDisc-C and 94.8% ACDF, and at 5 years 72.7% ProDisc-C and 63.5% ACDF. For all clinical outcomes for both groups, there was a statistically and clinically significant improvement at 2 and 5 years compared with baseline. At 5 years, ProDisc-C patients had statistically significantly less neck pain intensity and frequency. Both groups scored high VAS satisfaction scores at 5 years, with ProDisc-C 86.56 and ACDF 82.74. There were no reports of device failures or implant migration with ProDisc-C. The ProDisc-C patients maintained motion at their index level. At 5 years, the ProDisc-C patients had a statistically significantly lower rate of reoperation compared with ACDF patients (2.9% vs. 11.3%). CONCLUSION.: Five-year results show that TDR with ProDisc-C is a safe and effective treatment of single-level symptomatic cervical disc disease. Clinical outcomes were comparable with ACDF. ProDisc-C patients maintained motion at the index level and had significantly less neck pain intensity and frequency as well as a lower probability of secondary surgery.

Spine Tango is currently the only international spine registry in existence. It was developed under the auspices of Eurospine, the Spine Society of Europe, and is hosted at the University of Bern, Switzerland. The HJD Spine Center successfully tested Spine Tango during a 3-month pilot study and has since expanded documentation activities to more surgeons. Workflow integration and dedicated research staff are key factors for such an endeavor. Participation enables benchmarking against national and international peers and outcome research and quality assurance of surgical and non-surgical treatments.

BACKGROUND CONTEXT: Conjoined nerve roots are a relatively uncommon finding but are frequently undiagnosed on preoperative imaging studies. The presence of a conjoined root anomaly represents a significant potential for neurologic injury when nerve root mobilization is necessary during spinal procedures. PURPOSE: This comprehensive review of conjoined lumbar nerve roots encompasses preoperative diagnosis by physical examination and radiographic imaging studies, as well as the intraoperative management of conjoined nerve roots. STUDY DESIGN: Systematic review of existing literature. RESULTS: Findings have been described on standard magnetic resonance imaging (MRI) and computed tomography imaging to increase preoperative diagnosis rates. The literature lacks concrete recommendations regarding intraoperative techniques for conjoined root identification and management. CONCLUSIONS: Preoperative recognition and diagnosis of this anomaly has proven to be the best way to improve the chances of a successful procedure and avoid inadvertently damaging the nerve roots intraoperatively. Several radiographic signs of conjoined lumbar nerve roots have been described using standard MRI techniques including coronal T1- and T2-weighted sequences. Intraoperative management of conjoined nerve roots has not changed significantly since they were first identified, although diagnostic accuracy has improved with advanced MRI techniques.