Faculty Bibliography

BACKGROUND: Lumbosacral transitional vertebrae (LSTV) are increasingly recognized as a common anatomical variant associated with altered patterns of degenerative spine changes. This review will focus on the clinical significance of LSTV, disruptions in normal spine biomechanics, imaging techniques, diagnosis, and treatment. METHODS: A Pubmed search using the specific key words "LSTV," "lumbosacral transitional vertebrae," and "Bertolotti's Syndrome" was performed. The resulting group of manuscripts from our search was evaluated. RESULTS: LSTV are associated with alterations in biomechanics and anatomy of spinal and paraspinal structures, which have important implications on surgical approaches and techniques. LSTV are often inaccurately detected and classified on standard AP radiographs and MRI. The use of whole-spine images as well as geometric relationships between the sacrum and lumbar vertebra increase accuracy. Uncertainty regarding the cause, clinical significance, and treatment of LSTV persists. Some authors suggest an association between LSTV types II and IV and low back pain. Pseudoarticulation between the transverse process and the sacrum creates a "false joint" susceptible to arthritic changes and osteophyte formation potentially leading to nerve root entrapment. The diagnosis of symptomatic LSTV is considered with appropriate patient history, imaging studies, and diagnostic injections. A positive radionuclide study along with a positive effect from a local injection helps distinguish the transitional vertebra as a significant pain source. Surgical resection is reserved for a subgroup of LSTV patients who fail conservative treatment and whose pain is definitively attributed to the anomalous pseudoarticulation. CONCLUSIONS: Due to the common finding of low back pain and the wide prevalence of LSTV in the general population, it is essential to differentiate between symptoms originating from an anomalous psuedoarticulation from other potential sources of low back pain. Further studies with larger sample sizes and longer follow-up time would better demonstrate the effectiveness of surgical resection and help guide treatment.

BACKGROUND: Lateral transpsoas interbody fusion (LTIF) is a minimally invasive technique for achieving lumbar spinal fusion. While it has many advantages over open techniques it carries with it a distinct set of risks, most commonly post-operative ipsilateral thigh pain, weakness and sensory disturbances. It is vital for both the surgeon and patient to understand the risks for and outcomes of injury associated with this procedure. We conducted a systematic review of the literature to evaluate the incidence, risks, and long-term clinical outcomes of post-operative thigh symptoms in patients treated with LTIF. METHODS: We conducted a search of MEDLINE, EMBASE, CINAHL, Scopus, Web of Science and the Cochrane Collaboration Library, using keywords and MeSH terms, for English-language literature published through September 2014, as well as reference lists from key articles. Studies were then manually filtered to retrieve articles that met inclusion criteria. We were interested in studies that reported postoperative lower extremity symptoms after LTIF, such as pain, weakness and changes in sensation. The strength of evidence was determined based on precepts outlined by the Grades of Recommendation Assessment, Development and Evaluation Working Group (GRADE). RESULTS: A total of 392 articles were initially retrieved, with 24 ultimately meeting criteria for inclusion. The incidence of any post-operative thigh symptom varied, ranging as high as 60.7%, with 9.3% of patients experiencing a motor deficit related to direct nerve injury. Several studies reported cases of persistent symptoms at 6 months follow up. Additionally, inclusion of the L4-5 disc space and a longer duration of surgery were both identified as risks for developing postoperative thigh symptoms. CONCLUSION: The risk of postoperative thigh symptoms after LTIF is high. Thigh pain, paresthesias and weakness were the most commonly reported symptoms. While most patients' symptoms resolved by 6 months follow up, several studies reported patients with symptoms persistent as far as 12 months removed from surgery. Surgery at the L4-5 disc space and longer surgical duration place the patient at greater risk for developing postoperative and long-term thigh symptoms.

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.

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.

After anterior discectomy and decompression for cervical radiculopathy and myelopathy, cervical fusion has been the mainstay of treatment for decades. Ongoing investigation into cervical disc arthroplasty, with the goals of motion preservation and reduced adjacent segment degeneration, is occurring with enthusiasm. Understanding and recreating physiologic spinal motion is critical to these efforts and is an evolving process. Prospective randomized United States Food and Drug Administration regulated trials are now available for several devices with promising short-term and mid-term results. Long-term data are awaited with anticipation regarding the clinical, radiographic, and quality-based outcome measures. Ultimately, the decision to incorporate cervical disc arthroplasty into day-today practice will stem largely from the clinical outcome of the procedure, the long-term durability of the device, and the incidence of symptomatic adjacent segment degeneration, as compared with arthrodesis. 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins