Faculty Bibliography

BACKGROUND CONTEXT: Intraoperative neuromonitoring (IOM) of spinal cord and nerve root injury through somatosensory evoked potentials (SSEP), transcranial motor evoked potentials (TcMEP), spontaneous electromyography (sEMG), and triggered electromyography (tEMG) modalities is vital during spinal surgery. However, there are currently no practice guidelines or practice patterns for the utilization of unimodal or multimodal IOM (MIOM) for specific spinal surgeries. PURPOSE: This pilot study documents practice patterns of IOM for select spinal procedures. STUDY DESIGN/SETTING: Questionnaire survey. PATIENT SAMPLE: 22 fellowship-trained spine surgeons, both surgeons and neurosurgeons, were queried on use of IOM modality combination in various spine procedures. Surgical experience varied from three to 29 years, with an average of 14.4 years. OUTCOME MEASURES: Percentage of surgeons using IOM modality or MIOM combination was calculated for each procedure. METHODS: Spine surgeons at two hospitals were surveyed on practice patterns of use of intraoperative monitoring for three deformity procedures and 21 non-deformity procedures. RESULTS: Of the 18 (81%) responses received: 15 from orthopaedic surgeons and 3 from neurosurgeons. Deformity Surgery: For both cervical and thoracic deformity surgeries, all surgeons used at least SSEP+TcMEP. For cervical surgeries, 47% of surgeons additionally used sEMG while for thoracic 71% of surgeons additionally used sEMG+tEMG. Most surgeons (44%) used all four modalities for lumbar deformity surgery. Non-Deformity surgery: For patients having radiculopathy undergoing ACDF, SSEP alone was utilized by 29%. However, in patients undergoing ACDF with symptoms of myelopathy, most surgeons (31%) used SSEP+TcMEP with only 13% using SSEP only. Fourty-six percent of surgeons utilized SSEP+TcMEP+sEMG for cervical arthroplasty procedures. SSEP+ TcMEP+sEMG was most commonly used for posterior cervical laminoforaminotomy, posterior cervical laminectomy and posterior cervical laminect!

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 !

BACKGROUND: Cervical laminoplasty (CLP) and posterior cervical laminectomy and fusion (CLF) are well-established surgical procedures used in the treatment of cervical spondylotic myelopathy (CSM). In situations of clinical equipoise, an influential factor in procedural decision making could be the economic effect of the chosen procedure. The object of this study is to compare and analyze the total hospital costs and charges pertaining to patients undergoing CLP or CLF for the treatment of CSM. METHODS: We performed a retrospective review of 81 consecutive patients from a single institution; 55 patients were treated with CLP and 26 with CLF. CLP was performed via the double-door allograft technique that does not require implants, whereas laminectomy fusion procedures included metallic instrumentation. We analyzed 10,682 individual costs (HC) and charges (HCh) for all patients, as obtained from hospital accounting data. The Current Procedural Terminology codes were used to estimate the physicians' fees as such fees are not accounted for via hospital billing records. Total cost (TC) therefore equaled the sum of the hospital cost and the estimated physicians' fees. RESULTS: The mean length of stay was 3.7 days for CLP and 5.9 days for CLF (P < .01). There were no significant differences between the groups with respect to age, gender, previous surgical history, and medical insurance. The TC mean was $17,734 for CLP and $37,413 for CLF (P < .01). Mean HCh for CLP was 42% of that for CLF, and therefore the mean charge for CLF was 238% of that for CLP (P < .01). Mean HC was $15,426 for CLP and $32,125 for CLF (P < .01); the main contributor was implant cost (mean $2582). CONCLUSIONS: Our study demonstrates that, in clinically similar populations, CLP results in reduced length of stay, TC, and hospital charges. In CSM cases requiring posterior decompression, we demonstrate CLP to be a less costly procedure. However, in the presence of neck pain, kyphotic deformity, or gross instability, this procedure may not be sufficient and posterior CLF may be required.

BACKGROUND: Patients with cervical disc herniations resulting in radiculopathy or myelopathy from single level disease have traditionally been treated with Anterior Cervical Discectomy and Fusion (ACDF), yet Cervical Disc Arthroplasty (CDA) is a new alternative. Expert suggestion of reduced adjacent segment degeneration is a promising future result of CDA. A cost-utility analysis of these procedures with long-term follow-up has not been previously reported. METHODS: We reviewed single institution prospective data from a randomized trial comparing single-level ACDF and CDA in cervical disc disease. Both Medicare reimbursement schedules and actual hospital cost data for peri-operative care were separately reviewed and analyzed to estimate the cost of treatment of each patient. QALYs were calculated at 1 and 2 years based on NDI and SF-36 outcome scores, and incremental cost effectiveness ratio (ICER) analysis was performed to determine relative cost-effectiveness. RESULTS: Patients of both groups showed improvement in NDI and SF-36 outcome scores. Medicare reimbursement rates to the hospital were $11,747 and $10,015 for ACDF and CDA, respectively; these figures rose to $16,162 and $13,171 when including physician and anesthesiologist reimbursement. The estimated actual cost to the hospital of ACDF averaged $16,108, while CDA averaged $16,004 (p = 0.97); when including estimated physicians fees, total hospital costs came to $19,811 and $18,440, respectively. The cost/QALY analyses therefore varied widely with these discrepancies in cost values. The ICERs of ACDF vs CDA with Medicare reimbursements were $18,593 (NDI) and $19,940 (SF-36), while ICERs based on actual total hospital cost were $13,710 (NDI) and $9,140 (SF-36). CONCLUSIONS: We confirm the efficacy of ACDF and CDA in the treatment of cervical disc disease, as our results suggest similar clinical outcomes at one and two year follow-up. The ICER suggests that the non-significant added benefit via ACDF comes at a reasonable cost, whether we use actual hospital costs or Medicare reimbursement values, though the actual ICER values vary widely depending upon the CUA modality used. Long term follow-up may illustrate a different profile for CDA due to reduced cost and greater long-term utility scores. It is crucial to note that financial modeling plays an important role in how economic treatment dominance is portrayed.

STUDY DESIGN: Retrospective chart review. PURPOSE: To evaluate the incidence of potential total disc replacement (TDR) candidates among cervical and lumbar fusion patient populations using strict Food and Drug Administration (FDA) criteria and with relative exclusion criteria removed. OVERVIEW OF LITERATURE: Recent studies suggest that the potential percentage of patients that are candidates for TDR ranges from 0-5% in lumbar fusions and 43% in cervical fusions. METHODS: We performed a retrospective chart review of 280 consecutive patients who had lumbar (n = 174) and cervical (n = 106) fusion or TDR performed by one of four independent adult orthopaedic spine surgeons. Charts were screened for investigational device exemption (IDE) inclusion/exclusion criteria and later reanalyzed excluding relative exclusion criteria, such as history of chronic medical illness, twolevel disease (cervical cases), and history of prior fusion surgery in the anatomic region. RESULTS: Of the 174 lumbar surgeries, 10 were TDR with Prodisc-L and 164 were lumbar fusions. The most common TDR exclusion criteria were lytic spondylolisthesis or spinal stenosis (47.7% of patients) and more than 2 level degenerative disc disease (37.9%). 14.9% had no IDE exclusion criteria and would be considered candidates for TDR. After excluding the relative lumbar exclusion criteria, this percentage increased to 25.8%. Of the 106 cervical cases, 3 had a TDR with Prodisc-C and 103 had a cervical fusion. Twenty eight percent had no IDE exclusion criteria and would be considered candidates for cervical TDR. CONCLUSIONS: A larger percentage of cervical fusion candidates are potential candidates for TDR (28%) than lumbar fusion candidates (14.9%) based on the strict IDE criteria

BACKGROUND: Disc replacement arthroplasty previously has been shown to be an effective alternative to spine fusion for the treatment of single-level lumbar degenerative disc disease. The purpose of the present study was to determine the twenty-four-month results of a clinical trial of the ProDisc-L total disc replacement as compared with spinal fusion for the treatment of degenerative disc disease at two contiguous vertebral levels from L3 to S1. METHODS: A total of 237 patients were treated in a randomized controlled trial designed as a non-inferiority study for regulatory application purposes. Blocked randomization was performed with use of a 2:1 ratio of total disc arthroplasty to circumferential arthrodesis. Evaluations, including patient self-assessments, physical and neurological examinations, and radiographic examinations, were performed preoperatively, six weeks postoperatively, and three, six, twelve, eighteen, and twenty-four months postoperatively. RESULTS: At twenty-four months, 58.8% (eighty-seven) of 148 patients in the total disc replacement group were classified as a statistical success, compared with 47.8% (thirty-two) of sixty-seven patients in the arthrodesis group; non-inferiority was demonstrated. The mean Oswestry Disability Index in both groups significantly improved from baseline (p < 0.0001); the mean percentage improvement for the total disc replacement group was significantly better than that for the arthrodesis group (p = 0.0282). An established clinical criterion for success, a >/=15-point improvement in the Oswestry Disability Index from baseline, occurred in 73.2% (109) of 149 patients in the total disc replacement group and 59.7% (thirty-seven) of sixty-two patients in the arthrodesis group. The Short Form-36 physical component scores were significantly better for the total disc replacement group as compared with the arthrodesis group (p = 0.0141 at twenty-four months). Visual analog scale scores for satisfaction significantly favored total disc replacement from three to twenty-four months. At twenty-four months, 78.2% (111) of 142 patients in the total disc replacement group and 62.1% (thirty-six) of fifty-eight patients in the arthrodesis group responded "yes" when asked if they would have the same surgery again. Lumbar spine range of motion on radiographs averaged 7.8 degrees at the superior disc and 6.2 degrees at the inferior disc in patients with total disc replacement. Reduction in narcotics usage significantly favored the total disc replacement group at twenty-four months after surgery (p = 0.0020). CONCLUSIONS: Despite the relatively short duration of follow-up and design limitations, the present study suggests that two-level lumbar disc arthroplasty is an alternative to and offers clinical advantages in terms of pain relief and functional recovery in comparison with arthrodesis. Longer-term follow-up is needed to determine the risks for implant wear and/or degenerative segment changes.

BACKGROUND: Traditional surgical treatment of isthmic spondylolisthesis is posterior-lateral fusion, but the addition of anterior surgery has been explored. The purpose of this study was to evaluate the surgical and clinical outcomes of anterior-posterior surgical treatment for low-grade isthmic spondylolisthesis. METHODS: Retrospectively, we enrolled 23 consecutive patients (mean age of 50) who underwent surgical treatment for low grade isthmic spondylolisthesis. The mean follow-up was 10 months. Basic demographic and radiographic data was collected. Pre- and post-surgical clinical surveys (VAS, ODI, and SF-36) were collected. RESULTS: All 23 patients underwent anterior interbody fusion with a femoral ring allograft or ICBG in combination with posterior lumbar decompression and fusion with instrumentation. The average slip percentage decreased from 23.2% to 19.0% (p = 0.24) while slip angle increased from 9.8 degrees to 17.9 degrees (p < 0.001) and average disc height decreased from 1.9 cm to 0.80 cm (p < 0.001). VAS scores decreased from 7.1 to 2.4 (p < 0.001), ODI scores decreased from 52.5 to 28.1 (p < 0.001), and SF-36 scores increased in the Physical Component Scale (PCS) from 29.5 to 42.6 (p < 0.001). CONCLUSION: In our study, patients demonstrated an improvement in the ODI as well the physical component scores of the SF-36, thus having a good clinical outcome.

Pedicle screws (PS) can provide initial stabilization of anterior interbody femoral ring allograft (FRA) lumbar constructs. Translaminar screws (TLS) have also been advocated for this procedure. The objective of this study was to use an in vitro human cadaveric model to compare the stability of one-level anterior interbody lumbar constructs stabilized with PS and those stabilized with TLS. Five human cadaveric spinal motion segments (L4-S2) were biomechanically evaluated in the intact condition and using the follow- ing methods of stabilization: anterior interbody fusion with FRA, anterior FRA supplemented with PS, and anterior FRA supplemented with TLS. Stability was determined for each construct by measuring construct displacement as a function of applied load under the following conditions: compression, flexion, extension, lateral bending to each side, and axial torsion. There were no statistically significant differences in construct stability between FRA supplemented with PS and FRA supplemented with TLS under any of the loading conditions. In selected cases, supplementation of anterior femoral ring allograft with translaminar screws is a viable alternative to supplementation with pedicle screws.