Stephen K. Mendenhall

Minimally Invasive versus Open Transforaminal Lumbar Interbody Fusion for Degenerative Spondylolisthesis: Comparative Effectiveness and Cost-Utility Analysis

BACKGROUND Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for lumbar spondylolisthesis allows for the surgical treatment of back/leg pain while minimizing tissue injury and accelerating the patients recovery. Although previous results have shown shorter hospital stays and decreased intraoperative blood loss for MIS versus open TLIF, short- and long-term outcomes have been similar. Therefore, we performed comparative effectiveness and cost-utility analysis for MIS versus open TLIF. METHODS A total of 100 patients (50 MIS, 50 open) undergoing TLIF for lumbar spondylolisthesis were prospectively studied. Back-related medical resource use, missed work, and quality-adjusted life years were assessed. Cost of in-patient care, direct cost (2-year resource use × unit costs based on Medicare national allowable payment amounts), and indirect cost (work-day losses × self-reported gross-of-tax wage rate) were recorded, and the incremental cost-effectiveness ratio was calculated. RESULTS Length of hospitalization and time to return to work were less for MIS versus open TLIF (P = 0.006 and P = 0.03, respectively). MIS versus open TLIF demonstrated similar improvement in patient-reported outcomes assessed. MIS versus open TLIF was associated with a reduction in mean hospital cost of

Determination of minimum clinically important difference in pain, disability, and quality of life after extension of fusion for adjacent-segment disease: Clinical article

1758, indirect cost of

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

8474, and total 2-year societal cost of

Determination of minimum clinically important difference (MCID) in pain, disability, and quality of life after revision fusion for symptomatic pseudoarthrosis

9295 (P = 0.03) but similar 2-year direct health care cost and quality-adjusted life years gained. CONCLUSIONS MIS TLIF resulted in reduced operative blood loss, hospital stay and 2-year cost, and accelerated return to work. Surgical morbidity, hospital readmission, and short- and long-term clinical effectiveness were similar between MIS and open TLIF. MIS TLIF may represent a valuable and cost-saving advancement from a societal and hospital perspective.

Factors influencing 2-year health care costs in patients undergoing revision lumbar fusion procedures

OBJECT Spinal surgical outcome studies rely on patient-reported outcome (PRO) measurements to assess treatment effect. A shortcoming of these questionnaires is that the extent of improvement in their numerical scores lack a direct clinical meaning. As a result, the concept of minimum clinical important difference (MCID) has been used to measure the critical threshold needed to achieve clinically relevant treatment effectiveness. As utilization of spinal fusion has increased over the past decade, so has the incidence of adjacent-segment degeneration following index lumbar fusion, which commonly requires revision laminectomy and extension of fusion. The MCID remains uninvestigated for any PROs in the setting of revision lumbar surgery for adjacent-segment disease (ASD). METHODS In 50 consecutive patients undergoing revision surgery for ASD-associated back and leg pain, PRO measures of back and leg pain on a visual analog scale (BP-VAS and LP-VAS, respectively), Oswestry Disability Index (ODI), 12-Item Short Form Health Survey Physical and Mental Component Summaries (SF-12 PCS and MCS, respectively), and EuroQol-5D health survey (EQ-5D) were assessed preoperatively and 2 years postoperatively. The following 4 well-established anchor-based MCID calculation methods were used to calculate MCID: average change; minimum detectable change (MDC); change difference; and receiver operating characteristic curve (ROC) analysis for the following 2 separate anchors: health transition item (HTI) of the SF-36 and satisfaction index. RESULTS All patients were available for 2-year PRO assessment. Two years after surgery, a statistically significant improvement was observed for all PROs (mean changes: BP-VAS score [4.80 ± 3.25], LP-VAS score [3.28 ± 3.25], ODI [10.24 ± 13.49], SF-12 PCS [8.69 ± 12.55] and MCS [8.49 ± 11.45] scores, and EQ-5D [0.38 ± 0.45]; all p < 0.001). The 4 MCID calculation methods generated a range of MCID values for each of the PROs (BP-VAS score, 2.3-6.5; LP-VAS score, 1.7-4.3; ODI, 6.8-16.9; SF-12 PCS, 6.1-12.6; SF-12 MCS, 2.4-10.8; and EQ-5D, 0.27-0.54). The area under the ROC curve was consistently greater for the HTI anchor than the satisfaction anchor, suggesting this as a more accurate anchor for MCID. CONCLUSIONS Adjacent-segment disease revision surgery-specific MCID is highly variable based on calculation technique. The MDC approach with HTI anchor appears to be most appropriate for calculation of MCID after revision lumbar fusion for ASD 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 not significantly affected by choice of anchor. Based on this method, MCID following ASD revision lumbar surgery is 3.8 points for BP-VAS score, 2.4 points for LP-VAS score, 6.8 points for ODI, 8.8 points for SF-12 PCS, 9.3 points for SF-12 MCS, and 0.35 quality-adjusted life-years for EQ-5D.

Two-year comprehensive medical management of degenerative lumbar spine disease (lumbar spondylolisthesis, stenosis, or disc herniation): a value analysis of cost, pain, disability, and quality of life

BACKGROUND CONTEXT Persistent back pain and leg pain after index surgery is distressing to patients and spinal surgeons. Revision surgical treatment is technically challenging and has been reported to yield unpredictable outcomes. Recently, affective disorders, such as depression and anxiety, have been considered potential predictors of surgical outcomes across many disease states of chronic pain. There remains a paucity of studies assessing the predictive value of baseline depression on outcomes in the setting of revision spine surgery. PURPOSE To assess the predictive value of preoperative depression on 2-year postoperative outcome after revision lumbar surgery for symptomatic pseudarthrosis, adjacent segment disease (ASD), and same-level recurrent stenosis. STUDY DESIGN Retrospective cohort study. PATIENT SAMPLE One hundred fifty patients undergoing revision surgery for symptomatic ASD, pseudarthrosis, and same-level recurrent stenosis. OUTCOME MEASURES Patient-reported outcome measures were assessed using an outcomes questionnaire that included questions on health-state values (EQ-5D), disability (Oswestry Disability Index [ODI]), pain (visual analog scale), depression (Zung Self-Rating Depression Scale), and 12-Item Short Form Health Survey physical and mental component scores. METHODS One hundred fifty patients undergoing revision neural decompression and instrumented fusion for ASD (n=50), pseudarthrosis (n=47), or same-level recurrent stenosis (n=53) were included in this study. Preoperative Zung Self-Reported Depression Scale score was assessed for all patients. Preoperative and 2-year postoperative visual analog scale for back pain and leg pain scores and ODI were assessed. The association between preoperative Zung Depression Scale score and 2-year improvement in disability was assessed via multivariate regression analysis. RESULTS Compared to preoperative status, VAS-BP was significantly improved 2 years after surgery for ASD (8.72±1.85 vs. 3.92±2.84, p=.001), pseudoarthrosis (7.31±0.81 vs. 5.06±2.64, p=.001), and same-level recurrent stenosis (9.28±1.00 vs. 5.00±2.94, p=.001). Two-year ODI was also significantly improved after surgery for ASD (28.72±9.64 vs. 18.48±11.31, p=.001), pseudoarthrosis (29.74±5.35 vs. 25.42±6.00, p=.001), and same-level recurrent stenosis (36.01±6.00 vs. 21.75±12.07, p=.001). Independent of age, BMI, symptom duration, smoking, comorbidities, and level of preoperative pain and disability, increasing preoperative Zung depression score was significantly associated with less 2-year improvement in disability (ODI) after revision surgery for ASD, pseudoarthrosis, and recurrent stenosis. CONCLUSIONS Our study suggests that the extent of preoperative depression is an independent predictor of functional outcome after revision lumbar surgery for ASD, pseudoarthrosis, and recurrent stenosis. Future comparative effectiveness studies assessing outcomes after revision lumbar surgery should account for depression as a potential confounder. The Zung depression questionnaire may help risk stratify patients presenting for revision lumbar surgery.

Accurately measuring the quality and effectiveness of cervical spine surgery in registry efforts: determining the most valid and responsive instruments

BACKGROUND CONTEXT Spinal surgical outcome studies rely on patient reported outcome (PRO) measurements to assess the effect of treatment. A shortcoming of these questionnaires is that the extent of improvement in their numerical scores lacks a direct clinical meaning. As a result, the concept of minimum clinically important difference (MCID) has been used to measure the critical threshold needed to achieve clinically relevant treatment effectiveness. Post hoc anchor-based MCID methods have not been applied to the surgical treatment for pseudoarthrosis. PURPOSE To determine the most appropriate MCID values for visual analog scale (VAS), Oswestry Disability Index (ODI), Short Form (SF)-12 physical component score (PCS), and European Quality of Life 5-Dimensions (EQ-5D) in patients undergoing revision lumbar arthrodesis for symptomatic pseudoarthrosis. STUDY DESIGN/ SETTING: Retrospective cohort study. METHODS In 47 patients undergoing revision fusion for pseudoarthrosis-associated back pain, PRO measures of back pain (BP-VAS), ODI, physical quality of life (SF-12 PCS), and general health utility (EQ-5D) were assessed preoperatively and 2 years postoperatively. Four subjective post hoc anchor-based MCID calculation methods were used to calculate MCID (average change; minimum detectable change; change difference; and receiver operating characteristic curve analysis) for two separate anchors (health transition index (HTI) of SF-36 and satisfaction index). RESULTS All patients were available for a 2-year PRO assessment. Two years after surgery, a significant improvement was observed for all PROs; Mean change score: BP-VAS (2.3±2.6; p<.001), ODI (8.6%±13.2%; p<.001), SF-12 PCS (4.0±6.1; p=.01), and EQ-5D (0.18±0.19; p<.001). The four MCID calculation methods generated a wide range of MCID values for each of the PROs (BP-VAS: 2.0-3.2; ODI: 4.0%-16.6%; SF-12 PCS: 3.2-6.1; and EQ-5D: 0.14-0.24). There was no difference in response between anchors for any patient, suggesting that HTI and satisfaction anchors are equivalent in this patient population. The wide variations in calculated MCID values between methods precluded any ability to reliably determine what the true value is for meaningful change in this disease state. CONCLUSIONS Using subjective post hoc anchor-based methods of MCID calculation, MCID after revision fusion for pseudoarthrosis varies by as much as 400% per PRO based on the calculation technique. MCID was suggested to be as low as 2 points for ODI and 3 points for SF-12. These wide variations and low values of MCID question the face validity of such calculation techniques, especially when applied to heterogeneous disease and patient groups with a multitude of psychosocial confounders such as failed back syndromes. The variability of MCID thresholds observed in our study of patients undergoing revision lumbar fusion for pseudoarthrosis raises further questions to whether ante hoc or Delphi methods may be a more valid and consistent technique to define clinically meaningful, patient-centered changes in PRO measurements.

Accurately measuring outcomes after surgery for adult Chiari I malformation: determining the most valid and responsive instruments.

OBJECT Revision lumbar fusion procedures are technically challenging and can be associated with tremendous health care resource utilization and cost. There is a paucity of data regarding specific factors that significantly contribute to increased cost of care. In light of this, the authors set out to identify independent risk factors predictive of increasing 2-year direct health care costs after revision lumbar fusion. METHODS One hundred fifty patients undergoing revision instrument-assisted fusion for adjacent-segment disease (50 cases), pseudarthrosis (47 cases), or same-level stenosis (53 cases) were included in this study. Patient demographics, comorbidities, preoperative health states as assessed by patient-reported outcome questionnaires and perioperative complications were collected and analyzed. Two-year back-related medical resource utilization and direct health care costs were assessed. The independent association of all variables to increasing cost was assessed using multivariate linear regression analysis. RESULTS There was a wide range (

Extent of Preoperative Depression Is Associated with Return to Work After Lumbar Fusion for Spondylolisthesis

24,935-

Comprehensive Assessment of 1-Year Outcomes and Determination of Minimum Clinically Important Difference in Pain, Disability, and Quality of Life After Suboccipital Decompression for Chiari Malformation I in Adults

63,769) in overall 2-year direct costs for patients undergoing revision lumbar fusion (mean