Oran Aaronson

Utility of minimum clinically important difference in assessing pain, disability, and health state after transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis

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.

Post-operative infection after minimally invasive versus open transforaminal lumbar interbody fusion (TLIF): Literature review and cost analysis

INTRODUCTION Surgical site infection (SSI) in the setting of lumbar fusion is associated with significant morbidity and medical resource utilization. To date, there have been no studies conducted with sufficient power to directly compare the incidence of SSI following minimally invasive (MIS) vs. open TLIF procedures. Furthermore, studies are lacking that quantify the direct medical cost of SSI following fusion procedures. We set out to determine the incidence of SSI in patients undergoing MIS vs. open TLIF reported in the literature and to determine the direct hospital cost associated with the treatment of SSI following TLIF at our institution. METHODS A systematic Medline search was performed to identify all published studies assessing SSI after MIS or open TLIF. The cumulative incidence of SSI was calculated from all reported cohorts and compared between MIS vs. open TLIF. In order to determine the direct hospital costs associated with the treatment of SSI following TLIF, we retrospectively reviewed 120 consecutive TLIFs performed at our institution, assessed the incidence of SSI, and calculated the SSI-related hospital costs from accounting and billing records. RESULTS To date, there have been 10 MIS-TLIF cohorts (362 patients) and 20 open-TLIF cohorts (1 133 patients) reporting incidences of SSI. The cumulative incidence of reported SSI was significantly lower for MIS vs. open-TLIF (0.6% vs. 4.0%, p=0.0005). In our experience with 120 open TLIF procedures, SSI occurred in 6 (5.0%) patients. The mean hospital cost associated with the treatment of SSI following TLIF was

Robot-Assisted Endoscopic Intrauterine Myelomeningocele Repair: A Feasibility Study

29,110 in these 6 cases. The 3.4% decrease in reported incidence of SSI for MIS vs. open-TLIF corresponds to a direct cost savings of

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

98,974 per 100 MIS-TLIF procedures performed. CONCLUSIONS Post-operative wound infections following TLIF are costly complications. MIS vs. open TLIF is associated with a decreased reported incidence of SSI in the literature and may be a valuable tool in reducing hospital costs associated with spine care.

Cost-effectiveness of transforaminal lumbar interbody fusion for Grade I degenerative spondylolisthesis.

Background: Animal experiments have suggested that the intrauterine environment causes secondary injury to the congenitally dysplastic spinal cord. This in turn suggests that early closure of the myelomeningocele sac might prevent secondary injury and therefore improve neurologic outcome. This study was designed to examine the technical feasibility of performing intrauterine myelomeningocele repair using a robot-assisted endoscopic system in an animal model. Methods: Six fetal sheep underwent creation and repair of a full-thickness skin lesion using the da VinciTM system. Results: With the device’s advanced articulated instruments and three-dimensional optics, it was possible to endoscopically repair the induced skin defects. Conclusion: We conclude that, with the recent evolution in robotics and minimally invasive techniques, intrauterine endoscopic surgery has become a realistic goal that promises to reduce the associated risks of fetal surgery and extend the indications for its use.

Preoperative Zung Depression Scale predicts outcome after revision lumbar surgery for adjacent segment disease, recurrent stenosis, and pseudarthrosis

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.

Cost-effectiveness of multilevel hemilaminectomy for lumbar stenosis-associated radiculopathy.

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

Thoracic microendoscopic discectomy: a human cadaver study.

36,836 ±

Cost-utility analysis of minimally invasive versus open multilevel hemilaminectomy for lumbar stenosis.

11,800 (surgery cost,

Cognitive-Behavioral–Based Physical Therapy to Improve Surgical Spine Outcomes: A Case Series

21,311 ±