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Abstracts of the 2013 Annual Meeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves
Phoenix, Arizona • March 6–9, 2013
Cauda equina syndrome secondary to an absent inferior vena cava managed with surgical decompression
Case report
Mayshan Ghiassi, Mahan Ghiassi, Elyne Kahn, Luke Tomycz, Michael Ayad, and Oran Aaronson
The authors report on the case of a 24-year-old man who presented with back pain and radiculopathy due to epidural venous engorgement in the setting of a congenitally absent inferior vena cava. Despite initial improvement after steroid administration, the patient's health ultimately declined over a period of weeks, and signs and symptoms of cauda equina syndrome manifested. Lumbar decompression was performed and involved coagulation and resection of the compressive epidural veins. No complications occurred, and the patient made a full neurological recovery.
Cost per quality-adjusted life year gained of revision neural decompression and instrumented fusion for same-level recurrent lumbar stenosis: defining the value of surgical intervention
Clinical article
Owoicho Adogwa, Scott L. Parker, David N. Shau, Stephen K. Mendenhall, Oran Aaronson, Joseph S. Cheng, Clinton J. Devin, and Matthew J. McGirt
Object
Despite advances in technology and understanding in spinal physiology, reoperation for symptomatic same-level recurrent stenosis continues to occur. Although revision lumbar surgery is effective, attention has turned to the question of the utility and value of revision decompression and fusion procedures. To date, an analysis of cost and heath state gain associated with revision lumbar surgery for recurrent same-level lumbar stenosis has yet to be described. The authors set out to assess the 2-year comprehensive cost of revision surgery and determine its value in the treatment of same-level recurrent stenosis.
Methods
Forty-two patients undergoing revision decompression and instrumented fusion for same-level recurrent stenosis–associated leg and back pain were included in this study. Two-year total back-related medical resource utilization, missed work, and health state values (quality-adjusted life years [QALYs], calculated from the EQ-5D with US valuation) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Mean total 2-year cost per QALY gained after revision surgery was assessed.
Results
The mean (± SD) interval between prior and revision surgery was 4.16 ± 4.64 years. Bone morphogenetic protein was used in 7 cases of revision arthrodesis (16.7%). A mean cumulative 2-year gain of 0.84 QALY was observed after revision surgery. The mean total 2-year cost of revision fusion was $49,431 ± $7583 (surgery cost $21,060 ± $4459; outpatient resource utilization cost $9748 ± $5292; indirect cost $18,623 ± $9098). Revision decompression and extension of fusion was associated with a mean 2-year cost per QALY gained of $58,846.
Conclusions
In the authors' practice, revision decompression and fusion provided a significant gain in health state utility for patients with symptomatic same-level recurrent stenosis, with a 2-year cost per QALY gained of $58,846. When indicated, revision surgery for same-level recurrent stenosis is a valuable treatment option for patients experiencing back and leg pain secondary to this disease. The authors' findings provide a value measure of surgery that can be compared with the results of future cost-per-QALY-gained studies of medical management or alternative surgical approaches.
Long-term outcomes of revision fusion for lumbar pseudarthrosis
Clinical article
Owoicho Adogwa, Scott L. Parker, David Shau, Stephen K. Mendelhall, Joseph Cheng, Oran Aaronson, Clinton J. Devin, and Matthew J. McGirt
Object
The number of low-back fusion procedures for the treatment of spine disorders has increased steadily over the past 10 years. Lumbar pseudarthrosis is a potential complication of lumbar arthrodesis and can be associated with significant pain and disability. The aim of this study was to assess, using validated patient-reported outcomes measures, the long-term effectiveness of revision arthrodesis in the treatment of symptomatic pseudarthrosis.
Methods
This is a retrospective study of 47 patients who underwent revision lumbar arthrodesis for pseudarthrosis-associated back pain. Baseline 2-year outcomes were assessed using the following: visual analog scale (VAS) for back pain, Oswestry Disability Index (ODI), Zung Self-Rating Depression Scale, time to narcotic independence, time to return to work, EuroQol health-state utility, and physical and mental quality of life (Short Form [SF]–12 Physical and Mental Component Summary scores).
Results
The mean duration of time between prior fusion and development of symptomatic pseudarthrosis was 2.69 years. Bone morphogenetic protein was used in 4 cases (8.5%) of revision arthrodesis. A significant improvement in VAS back pain (7.31 ± 0.81 vs 5.06 ± 2.64, p = 0.001), ODI (29.74 ± 5.35 vs 25.42 ± 6.0, p = 0.001), and physical health SF-12 (23.83 ± 6.89 vs 27.85 ± 8.90, p = 0.001) scores was observed when comparing baseline and 2-year post–revision arthrodesis scores, respectively, with a mean cumulative 2-year gain of 0.35 quality-adjusted life years. The median time to narcotics independence was 12.16 (interquartile range 1.5–24.0) months and the median time to return to work was 4 months (interquartile range 3–5 months). By 2 years after revision surgery, no patients had experienced pseudarthrosis. The SF-12 Mental Component Summary (44.72 ± 7.90 vs 43.46 ± 7.51, p = 0.43) and Zung Self-Rating Depression Scale scores (39.36 ± 7.48 vs 41.39 ± 10.72, p = 0.37) were not significantly improved by 2 years.
Conclusions
The authors' study suggests that revision lumbar arthrodesis for symptomatic pseudarthrosis provides improvement in low-back pain, disability, and quality of life. Revision lumbar arthrodesis should be considered a viable treatment option for patients with pseudarthrosis-related back pain. Mental health symptoms from pseudarthrosis-associated back pain may be more refractory to revision surgery.
Cost-effectiveness of transforaminal lumbar interbody fusion for Grade I degenerative spondylolisthesis
Clinical article
Owoicho Adogwa, Scott L. Parker, Brandon J. Davis, Oran Aaronson, Clinton Devin, Joseph S. Cheng, and Matthew J. McGirt
Object
Transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis-associated back and leg pain is associated with improvement in pain, disability, and quality of life. However, given the rising health care costs associated with spinal fusion procedures and varying results of recent cost-utility studies, the cost-effectiveness of TLIF remains unclear. The authors set out to assess the comprehensive costs of TLIF at their institution and to determine its cost-effectiveness in the treatment of degenerative spondylolisthesis.
Methods
Forty-five patients undergoing TLIF for Grade I degenerative spondylolisthesis–associated back and leg pain after 6–12 months of conservative therapy were included. The authors assessed the 2-year back pain visual analog scale (VAS) score, leg pain VAS score, Oswestry Disability Index, and total back-related medical resource utilization, missed work, and health-state values (quality-adjusted life years [QALYs], calculated from EQ-5D with US valuation). Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). The mean total 2-year cost per QALY gained after TLIF was assessed.
Results
Compared with preoperative health states reported after at least 6 months of medical management, a significant improvement in back pain VAS score, leg pain VAS score, and Oswestry Disability Index was observed 2 years after TLIF, with a mean 2-year gain of 0.86 QALYs. The mean ± SD total 2-year cost of TLIF was $36,836 ± $11,800 (surgery cost, $21,311 ± $2800; outpatient resource utilization cost, $3940 ± $2720; indirect cost, $11,584 ± $11,363). Transforaminal lumbar interbody fusion was associated with a mean 2-year cost per QALY gained of $42,854.
Conclusions
Transforaminal lumbar interbody fusion improved pain, disability, and quality of life in patients with degenerative spondylolisthesis–associated back and leg pain. The total cost per QALY gained for TLIF was $42,854 when evaluated 2 years after surgery with Medicare fees, suggesting that TLIF is a cost-effective treatment of lumbar spondylolisthesis.
Utility of minimum clinically important difference in assessing pain, disability, and health state after transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis
Clinical article
Scott L. Parker, Owoicho Adogwa, Alexandra R. Paul, William N. Anderson, Oran Aaronson, Joseph S. Cheng, and Matthew J. McGirt
Object
Outcome studies for spine surgery rely on patient-reported outcomes (PROs) to assess treatment effects. Commonly used health-related quality-of-life questionnaires include the following scales: back pain and leg pain visual analog scale (BP-VAS and LP-VAS); the Oswestry Disability Index (ODI); and the EuroQol-5D health survey (EQ-5D). A shortcoming of these questionnaires is that their numerical scores lack a direct meaning or clinical significance. Because of this, the concept of the minimum clinically important difference (MCID) has been put forth as a measure for the critical threshold needed to achieve treatment effectiveness. By this measure, treatment effects reaching the MCID threshold value imply clinical significance and justification for implementation into clinical practice.
Methods
In 45 consecutive patients undergoing transforaminal lumbar interbody fusion (TLIF) for low-grade degenerative lumbar spondylolisthesis-associated back and leg pain, PRO questionnaires measuring BP-VAS, LPVAS, ODI, and EQ-5D were administered preoperatively and at 2 years postoperatively, and 2-year change scores were calculated. Four established anchor-based MCID calculation methods were used to calculate MCID, as follows: 1) average change; 2) minimum detectable change (MDC); 3) change difference; and 4) receiver operating characteristic curve analysis for two separate anchors (the health transition index [HTI] of the 36-Item Short Form Health Survey [SF-36], and the satisfaction index).
Results
All patients were available at the 2-year follow-up. The 2-year improvements in BP-VAS, LP-VAS, ODI, and EQ-5D scores were 4.3 ± 2.9, 3.8 ± 3.4, 19.5 ± 11.3, and 0.43 ± 0.44, respectively (mean ± SD). The 4 MCID calculation methods generated a range of MCID values for each of the PROs (BP-VAS, 2.1–5.3; LP-VAS, 2.1–4.7; ODI, 11–22.9; and EQ-5D, 0.15–0.54). The mean area under the curve (AUC) for the receiver operating characteristic curve from the 4 PRO-specific calculations was greater for the HTI versus satisfaction anchor (HTI [AUC 0.73] vs satisfaction [AUC 0.69]), suggesting HTI as a more accurate anchor.
Conclusions
The TLIF-specific MCID is highly variable based on calculation technique. The MDC approach with the SF-36 HTI anchor appears to be most appropriate for calculating MCID because it provided a threshold above the 95% CI of the unimproved cohort (greater than the measurement error), was closest to the mean change score reported by improved and satisfied patients, and was least affected by the choice of anchor. Based on the MDC method with HTI anchor, MCID scores following TLIF are 2.1 points for BP-VAS, 2.8 points for LP-VAS, 14.9 points for ODI, and 0.46 quality-adjusted life years for EQ-5D.
Abstracts of the 2011 Meeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves March 2011
Survival of patients with malignant primary osseous spinal neoplasms: results from the Surveillance, Epidemiology, and End Results (SEER) database from 1973 to 2003
Clinical article
Debraj Mukherjee, Kaisorn L. Chaichana, Ziya L. Gokaslan, Oran Aaronson, Joseph S. Cheng, and Matthew J. McGirt
Object
Malignant primary osseous spinal neoplasms are aggressive tumors that remain associated with poor outcomes despite aggressive multidisciplinary treatment measures. To date, prognosis for patients with these tumors is based on results from small single-center patient series and controlled trials. Large population-based observational studies are lacking. To assess national trends in histology-specific survival, the authors reviewed patient survival data spanning 30 years (1973–2003) from the Surveillance, Epidemiology, and End Results (SEER) registry, a US population-based cancer registry.
Methods
The SEER registry was queried to identify cases of histologically confirmed primary spinal chordoma, chondrosarcoma, osteosarcoma, or Ewing sarcoma using coding from the International Classification of Disease for Oncology, Third Edition. Association of survival with histology, metastasis status, tumor site, and year of diagnosis was assessed using Cox proportional-hazards regression analysis.
Results
A total of 1892 patients were identified with primary osseous spinal neoplasms (414 with chordomas, 579 with chondrosarcomas, 430 with osteosarcomas, and 469 with Ewing sarcomas). Chordomas presented in older patients (60 ± 17 years; p < 0.01) whereas Ewing sarcoma presented in younger patients (19 ± 11 years; p < 0.01) compared with patients with all other tumors. The relative incidence of each tumor type remained similar per decade from 1973 to 2003. African Americans comprised a significantly greater proportion of patients with osteosarcomas than other tumors (9.6% vs 3.5%, respectively; p < 0.01). Compared with the sacrum, the mobile spine was more likely to be the site of tumor location for chordomas than for all other tumors (47% vs 23%, respectively; p < 0.05). Osteosarcoma and Ewing sarcoma were 3 times more likely than chondrosarcoma and chordoma to present with metastasis (31% vs 8%, respectively). Resection was performed more frequently for chordoma (88%) and chondrosarcoma (89%) than for osteosarcoma (61%) and Ewing sarcoma (53%). Overall median survival was histology-specific (osteosarcoma, 11 months; Ewing sarcoma, 26 months; chondrosarcoma, 37 months; chordoma, 50 months) and significantly worse in patients with metastasis at presentation for all tumor types. Survival did not significantly differ as a function of site (mobile spine vs sacrum/pelvis) for any tumor type, but more recent year of diagnosis was associated with improved survival for isolated spinal Ewing sarcoma (hazard ration [HR] 0.95; p = 0.001), chondrosarcoma (HR 0.98; p = 0.009), and chordoma (HR 0.98; p = 0.10), but not osteosarcoma.
Conclusions
In this analysis of a 30-year, US population-based cancer registry (SEER), the authors provide nationally representative prognosis and survival data for patients with malignant primary spinal osseous neoplasms. Overall patient survival has improved for isolated spine tumors with advancements in care over the past 4 decades. These results may be helpful in providing historical controls for understanding the efficacy of new treatment paradigms, patient education, and guiding level of aggressiveness in treatment strategies.
