SF-6D values stratified by specific diagnostic indication

Cost-utility Analysis Comparing Bracing Versus Observation for Skeletally Immature Patients with Thoracic Scoliosis

STUDY DESIGN

Cost-utility analysis.

OBJECTIVE

This study aimed to investigate the cost-utility of bracing versus observation in patients with thoracic scoliosis who would be indicated for bracing.

SUMMARY OF BACKGROUND DATA

There is high-quality evidence that bracing can prevent radiographic progression of spinal curvature in adolescent idiopathic scoliosis (AIS) patients with curves between 25° and 40° and Risser 0 to 2 skeletal maturity index. However, to our knowledge, the cost-utility of bracing in AIS has not been established.

METHODS

A decision-analysis model comparing bracing versus observation was developed for a hypothetical 10-year old girl (Risser 0, Sanders 3) with a 35° main thoracic curve. We estimated the probability, cost, and quality-adjusted life years (QALY) for each node based on comprehensive review of the literature. Costs were adjusted for inflation based on Consumer Price Index and reported in terms of 2020 real dollars. Incremental net monetary benefit (INMB) was calculated based on a probabilistic sensitivity analysis using Monte Carlo simulations of 1000 hypothetical patients. One-way sensitivity analyses were performed by varying cost, probability, and QALY estimates.

RESULTS

Our decision-analysis model revealed that bracing was the dominant treatment choice over observation at $50,000/QALY willingness to pay threshold. In simulation analysis of a hypothetical patient cohort, bracing was associated with lower net lifetime costs ($60,377 ± $5,340 with bracing vs. $85,279 ± $4543 with observation) and higher net lifetime QALYs (24.1 ± 2.0 with bracing vs. 23.9 ± 1.8 with observation). Bracing was associated with an INMB of $36,093 (95% confidence interval $18,894-$55,963) over observation over the patient's lifetime. The model was most sensitive to the impact of bracing versus observation on altering the probability of requiring surgery, either as an adolescent or an adult.

CONCLUSION

Cost-utility analysis supports scoliosis bracing as the preferred choice in management of appropriately indicated AIS patients with thoracic scoliosis.Level of Evidence: 5.

Construct validity and responsiveness of commonly used patient reported outcome instruments in decompression for lumbar spinal stenosis

BACKGROUND

Validity and responsiveness of Oswestry disability index (ODI), Roland Morris disability questionnaires (RMDQ), Short Form-12 Physical Component Score (SF-12 PCS) and Short Form-12 Mental Component Score (SF-12 MCS) in patients undergoing open decompression for lumbar canal stenosis has not been previously reported.

METHODS

Outcome assessment was prospectively evaluated using the ODI, RMDQ, SF-12 PCS and SF-12 MCS pre-intervention and at average follow-up of three months post-intervention. Pearson correlation coefficient was used to evaluate the association between change in values of ODI, RMDQ, SF-12 PCS and SF-12 MCS. Distribution based methods (Effect size [ES], standardised response mean [SRM]) and anchor based method (Area under the curve [AUC] of receiver operating curve [ROC]) were used to determine responsiveness. AUC value ≥ 0.70 is considered as adequate level of responsiveness and the outcome instrument with the largest AUC is considered to be the most responsive outcome instrument.

RESULTS

This study included 77 participants. Responsiveness was assessed at a mean follow-up of 12 weeks postoperatively. There was significant strong correlation between ODI and RMDQ (r = 0.65, p < 0.0001). The ES of ODI, RMDQ, SF-12 PCS and SF-12 MCS were 1.54, 1.48, 1.85 and 0.51 respectively. The SRM of RMDQ, ODI, SF-12 PCS and SF-12 MCS were 1.22, 1.17, 1.0 and 0.47 respectively. AUC of ODI, RMDQ, SF-12 PCS and SF-12 MCS were 0.83-0.88, 0.82 to 0.86, 0.78 to 0.81 and 0.69 to 0.70 respectively.

CONCLUSION

It is recommended to use either ODI or RMDQ as region specific patient reported outcome instrument and SF-12 PCS as a health related quality of life outcome instrument to evaluate outcome after decompressive laminectomy for lumbar canal stenosis.

Cost-Utility Analysis of Operative Versus Nonoperative Treatment of Thoracic Adolescent Idiopathic Scoliosis

STUDY DESIGN

Cost-utility analysis OBJECTIVE.: To compare the cost utility of operative versus nonoperative treatment of adolescent idiopathic scoliosis (AIS) and identity factors that influence cost-utility estimates.

SUMMARY OF BACKGROUND DATA

AIS affects 1% to 3% of children aged 10 to 16 years. When the major coronal curve reaches 50°, operative treatment may be considered. The cost utility of operative treatment of AIS is unknown.

METHODS

A decision-analysis model comparing operative versus nonoperative treatment was developed for a hypothetical 15-year-old skeletally mature girl with a 55° right thoracic (Lenke 1) curve. The AIS literature was reviewed to estimate the probability, health utility, and quality-adjusted life years (QALYs) for each event. For the conservative model, we assumed that operative treatment did not result directly in any QALYs gained, and the health utility in AIS patients was the same as the age-matched US population mean. Costs were inflation-adjusted at 3.22% per year to 2015 US dollars. Costs and benefits were discounted at 3%. Probabilistic sensitivity analysis was performed using mixed first-order and second-order Monte Carlo simulations. Incremental cost utility ratio (ICUR) and incremental net monetary benefit were calculated. One-way sensitivity analyses were performed by varying cost, probability, and QALY estimates.

RESULTS

Operative treatment was favored in 98.5% of simulations, with a median ICUR of $20,600/QALY (95% confidence interval, $20,500-$21,900) below the societal willingness-to-pay threshold (WTPT) of $50,000/QALY. The median incremental net monetary benefit associated with operative treatment was $15,100 (95% confidence interval, $14,800-$15,700). Operative treatment produced net monetary benefit across various WTPTs. Factors that most affected the ICUR were net costs associated with uncomplicated operative treatment, undergoing surgery during adulthood, and development of pulmonary complications.

CONCLUSION

Cost-utility analysis suggests that operative treatment of AIS is favored over nonoperative treatment and falls below the $50,000/QALY WTPT for patients with Lenke 1 curves.

LEVEL OF EVIDENCE

2.

Quality of Life in Patients Undergoing Spine Surgery: Systematic Review and Meta-Analysis

STUDY DESIGN

Meta-analysis.

OBJECTIVE

Despite the increasing importance of tracking clinical outcomes using valid patient-reported outcome measures, most providers do not routinely obtain baseline preoperative health-related quality of life (HRQoL) data in patients undergoing spine surgery, precluding objective outcomes analysis in individual practices. We conducted a meta-analysis of pre- and postoperative HRQoL data obtained from the most commonly published instruments to use as reference values.

METHODS

We searched PubMed, EMBASE, and an institutional registry for studies reporting EQ-5D, SF-6D, and Short Form-36 Physical Component Summary scores in patients undergoing surgery for degenerative cervical and lumbar spinal conditions published between 2000 and 2014. Observational data was pooled meta-analytically using an inverse variance-weighted, random-effects model, and statistical comparisons were performed.

RESULTS

Ninety-nine articles were included in the final analysis. Baseline HRQoL scores varied by diagnosis for each of the 3 instruments. On average, postoperative HRQoL scores significantly improved following surgical intervention for each diagnosis using each instrument. There were statistically significant differences in baseline utility values between the EQ-5D and SF-6D instruments for all lumbar diagnoses.

CONCLUSIONS

The pooled HRQoL values presented in this study may be used by practitioners who would otherwise be precluded from quantifying their surgical outcomes due to a lack of baseline data. The results highlight differences in HRQoL between different degenerative spinal diagnoses, as well as the discrepancy between 2 common utility-based instruments. These findings emphasize the need to be cognizant of the specific instruments used when comparing the results of outcome studies.

Which Domains of the ODI Best Predict Change in Physical Function in Patients After Surgery for Degenerative Lumbar Spondylolisthesis?

STUDY DESIGN

A retrospective review.

OBJECTIVE

The purpose of this study is to determine the differential improvement of the various individual items of the Oswestry Disability Index (ODI) and to determine their relationship to other measures of Health Related Quality of Life (HRQOL).

SUMMARY OF BACKGROUND DATA

The ODI is an easily scored, common, 10-item questionnaire about symptoms relevant to lumbar spine pathology. It is not clear if all of the items can be reliably applied to spine surgery. The purpose of this study is to determine the differential improvement of the various individual items of the ODI and to determine their relationship to other measures of HRQOL.

METHODS

Analysis of a prospective registry of patients treated at an academic medical center was undertaken. At baseline, standardized outcome measures including ODI and SF12 PCS were collected on all patients undergoing elective fusion surgery for degenerative spondylolisthesis. Multiple linear regressions were performed using change in SF12 PCS as the dependent variable and change in ODI components as the independent variables.

RESULTS

Baseline and 1-year follow-up data were collected on 196 patients (mean age 60.4 years). There were statistically significant differences in improvement among ODI items. Surprisingly, the most improvement after surgery was noted in the standing, sex life, and social life domains. The least improvement was noted in the personal care, sleeping, and sitting domains. Linear regression for change in ODI components versus change in SF-12 PCS revealed a significant correlation (R = 0.353, P ≤ 0.001). The only retained domains in the final model were change in lifting, standing, and traveling as predictors for ΔPCS.

CONCLUSION

All domains of the ODI do not improve equally after surgery for degenerative spondylolisthesis. Some of the domains that improve most (e.g., sex life) have no discernible relationship to the known pathophysiology of degenerative spondylolisthesis. Based upon these results, we conclude that the item bank and composite scoring of the ODI are inappropriate for evaluating quality of life in studies of surgically treated degenerative spondylolisthesis patients.

LEVEL OF EVIDENCE

3.

Surgery for degenerative cervical myelopathy: a patient-centered quality of life and health economic evaluation

BACKGROUND CONTEXT

Degenerative cervical myelopathy (DCM) represents the most common cause of non-traumatic spinal cord impairment in adults. Surgery has been shown to improve neurologic symptoms and functional status, but it is costly. As sustainability concerns in the field of health care rise, the value of care has come to the forefront of policy decision-making. Evidence for both health-related quality of life outcomes and financial expenditures is needed to inform resource allocation decisions.

PURPOSE

This study aimed to estimate the lifetime incremental cost-utility of surgical treatment for DCM.

DESIGN/SETTING

This is a prospective observational cohort study at a Canadian tertiary care facility.

PATIENT SAMPLE

We recruited all patients undergoing surgery for DCM at a single center between 2005 and 2011 who were enrolled in either the AOSpine Cervical Spondylotic Myelopathy (CSM)-North America study or the AOSpine CSM-International study.

OUTCOME MEASURES

Health utility was measured at baseline and at 6, 12, and 24 months following surgery using the Short Form-6D (SF-6D) health utility score. Resource expenditures were calculated on an individual level, from the hospital payer perspective over the 24-month follow-up period. All costs were obtained from a micro-cost database maintained by the institutional finance department and reported in Canadian dollars, inflated to January 2015 values.

METHODS

Quality-adjusted life year (QALY) gains for the study period were determined using an area under the curve calculation with a linear interpolation estimate. Lifetime incremental cost-to-utility ratios (ICUR) for surgery were estimated using a Markov state transition model. Structural uncertainty arising from lifetime extrapolation and the single-arm cohort design of the study were accounted for by constructing two models. The first included a highly conservative assumption that individuals undergoing nonoperative management would not experience any lifetime neurologic decline. This constraint was relaxed in the second model to permit more general parameters based on the established natural history. Deterministic and probabilistic sensitivity analyses were employed to account for parameter uncertainty. All QALY gains and costs were discounted at a base of 3% per annum. Statistical significance was set at the .05 level.

RESULTS

The analysis included 171 patients; follow-up was 96.5%. Mean age was 58.2±12.0 years and baseline health utility was 0.56±0.14. Mean QALY gained over the 24-month study period was 0.139 (95% confidence interval: 0.109-0.170, p<.001) and the mean 2-year cost of treatment was $19,217.82±12,404.23. Cost associated with the operation comprised 65.7% of the total. The remainder was apportioned over presurgical preparation and postsurgical recovery. Three patients required a reoperation over the 2-year follow-up period. The costs of revision surgery represented 1.85% of the total costs. Using the conservative model structure, the estimated lifetime ICUR of surgical intervention was $20,547.84/QALY gained, with 94.7% of estimates falling within the World Health Organization definition of "very cost-effective" ($54,000 CAD). Using the more general model structure, the estimated lifetime ICUR of surgical intervention was $11,496.02/QALY gained, with 97.9% of estimates meeting the criteria to be considered "very cost-effective."

CONCLUSIONS

Surgery for DCM is associated with a significant quality of life improvement. The intervention is cost-effective and, from the perspective of the hospital payer, should be supported.

Surgical Outcome Predictor in Degenerative Lumbar Spinal Disease Based on Health Related Quality of Life Using Euro-Quality 5 Dimensions Analysis

PURPOSE

We aim to introduce the predictive value of a quantitatively described formula model in a multicenter prospective analysis using the EuroQol-5 dimensions (EQ-5D) health scale to anticipate postoperative improvement in patients with degenerative lumbar spine disease (DLSD).

MATERIALS AND METHODS

Quality of life was evaluated in 376 patients from 17 tertiary hospitals before and after spinal decompression and fusion surgery. The five items of the EQ-5D, mobility (M), self-care (S), usual activities (A), pain/discomfort (P), and anxiety/depression (D), were checked as level 1, 2, or 3, with 3 being the worst. A minimal significant change in the calculated EQ-5D (cEQ-5D) was set as 0.05. Logistic regression analysis was performed to predict the highest successful outcome (cEQ-5D improvement after operation >0.05) with the given sets of 5 items of the EQ-5D.

RESULTS

In the cEQ-5D analysis, among patients with a formula score of S+A+2×P+D≤8, 18/68 (27%) showed significant improvement in the cEQ-5D at 1 year postoperatively (p<0.05). However, in patients with a formula score of ≥9, 265/308 (86%) demonstrated significant improvements in the cEQ-5D at 1 year postoperatively (p<0.05).

CONCLUSION

We suggest that S+A+2×P+D≥9 in the EQ-5D can quantitatively describe the better surgical outcome predictors for DLSD. With a definite DLSD lesion confirmed by an imaging study, patients who meet the formula scores of 9 or over and have refractory symptoms to non-operative treatment could be better surgical candidates resulting in satisfactory surgical outcomes of over 86%, than those who scored 8 or lower.

Incremental cost-effectiveness of adult spinal deformity surgery: observed quality-adjusted life years with surgery compared with predicted quality-adjusted life years without surgery

OBJECT

Incremental cost-effectiveness analysis is critical to the efficient allocation of health care resources; however, the incremental cost-effectiveness ratio (ICER) of surgical versus nonsurgical treatment for adult spinal deformity (ASD) has eluded the literature, due in part to inherent empirical difficulties when comparing surgical and nonsurgical patients. Using observed preoperative health-related quality of life (HRQOL) for patients who later underwent surgery, this study builds a statistical model to predict hypothetical quality-adjusted life years (QALYs) without surgical treatment. The analysis compares predicted QALYs to observed postoperative QALYs and forms the resulting ICER.

METHODS

This was a single-center (Baylor Scoliosis Center) retrospective analysis of consecutive patients undergoing primary surgery for ASD. Total costs (expressed in 2010 dollars) incurred by the hospital for each episode of surgical care were collected from administrative data and QALYs were calculated from the 6-dimensional Short-Form Health Survey, each discounted at 3.5% per year. Regression analysis was used to predict hypothetical QALYs without surgery based on preoperative longitudinal data for 124 crossover surgical patients with similar diagnoses, baseline HRQOL, age, and sex compared with the surgical cohort. Results were projected through 10-year follow-up, and the cost-effectiveness acceptability curve (CEAC) was estimated using nonparametric bootstrap methods.

RESULTS

Three-year follow-up was available for 120 (66%) of 181 eligible patients, who were predominantly female (89%) with average age of 50. With discounting, total costs averaged $125,407, including readmissions, with average QALYs of 1.93 at 3-year follow-up. Average QALYs without surgery were predicted to be 1.6 after 3 years. At 3- and 5-year follow-up, the ICER was $375,000 and $198,000, respectively. Projecting through 10-year follow-up, the ICER was $80,000. The 10-year CEAC revealed a 40% probability that the ICER was $80,000 or less, a 90% probability that the ICER was $90,000 or less, and a 100% probability that the ICER was less than $100,000.

CONCLUSIONS

Based on the WHO's suggested upper threshold for cost-effectiveness (3 times per capita GDP, or $140,000 in 2010 dollars), the analysis reveals that surgical treatment for ASD is cost-effective after a 10-year period based on predicted deterioration in HRQOL without surgery. The ICER well exceeds the WHO threshold at earlier follow-up intervals, highlighting the importance of the durability of surgical treatment in assessing the value of surgical intervention. Due to the study's methodology, the results are dependent on the predicted deterioration in HRQOL without surgery. As such, the results may not extend to patients whose HRQOL would remain steady without surgery. Future research should therefore pursue a direct comparison of QALYs for surgical and nonsurgical patients to better understand the cost-effectiveness of surgery for the average ASD patient.

The Nationwide Inpatient Sample database does not accurately reflect surgical indications for fusion

Object

The rates of lumbar spinal fusion operations have increased dramatically over the past 2 decades, and several studies based on administrative databases such as the Nationwide Inpatient Sample (NIS) have suggested that the greatest rise is in the general categories of degenerative disc disease and disc herniation, neither of which is a well-accepted indication for lumbar fusion. The administrative databases classify cases with the International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM). The ICD-9-CM discharge codes are not generated by surgeons but rather are assigned by trained hospital medical coders. It is unclear how accurately they capture the surgeon's indication for fusion. The authors sought to compare the ICD-9-CM code(s) assigned by the medical coder to the surgeon's indication based on a review of the medical chart.

Methods

A retrospective review was undertaken of all lumbar fusions performed at our institution by the department of neurosurgery between 8/1/2011 and 8/31/2013. Based on the authors' review, the indication for fusion for each case was categorized as spondylolisthesis, deformity, tumor, infection, nonpathological fracture, pseudarthrosis, adjacent-level degeneration, stenosis, degenerative disc pathology, or disc herniation. These surgeon diagnoses were compared with the primary ICD-9-CM codes that were submitted to administrative databases.

Results

There were 178 lumbar fusion operations performed for 170 hospital admissions. There were 44 hospitalizations in which fusion was performed for tumor, infection, or nonpathological fracture; the remaining 126 were for degenerative diagnoses. For these degenerative cases, the primary ICD-9-CM diagnosis matched the surgeon's diagnosis in only 61 of 126 degenerative cases (48.4%). When both the primary and all secondary ICD-9-CM diagnoses were considered, the indication for fusion was identified in 100 of 126 cases (79.4%).

Conclusions

Characterizing indications for fusion based solely on primary ICD-9-CM codes extracted from large administrative databases does not accurately reflect the surgeon's indication. While these databases may accurately describe national rates of lumbar fusion surgery, the lack of fidelity in the source codes limits their role in accurately identifying indications for surgery. Studying relationships among indications, complications, and outcomes stratified solely by ICD-9-CM codes is not well founded.

Changes in health utility, disability, and health-related quality of life in patients after spinal fusion: a 2-year follow-up study

STUDY DESIGN

Prospective longitudinal database study.

OBJECTIVE

To evaluate changes in health utility, disability, and health-related quality of life (HRQOL) in patients undergoing spinal fusion.

SUMMARY OF BACKGROUND DATA

Recently, measuring disability, HRQOL, and health utility has become important when defining the value of surgical interventions.

METHODS

Data of spinal fusion patients from a prospective longitudinal database were analyzed. Health utility was captured by SF-6D (six dimensional health state classification from the 36-dimensional Short Form Health Survey) score, disability by Oswestry Disability Index, and HRQOL by the 36-Item Short Form Health Survey. The changes in these scores were compared between the groups during the 2-year follow-up.

RESULTS

Altogether 242 patients were stratified into 5 groups according to the surgical indication: degenerative spondylolisthesis (n = 140), isthmic spondylolisthesis (n = 39), spinal stenosis (n = 23), disc pathology (n = 15), and postoperative conditions (n = 25). The mean age varied from 48 years in isthmic spondylolisthesis group to 66 years in the groups with degenerative spondylolisthesis or spinal stenosis. Preoperatively, the surgical indication subgroups differed significantly from each other according to utility, disability, and the physical component summary score of the HRQOL. Isthmic spondylolisthesis group had the best and the group of postoperative conditions the worst preoperative values. Nevertheless, the SF-6D, the Oswestry Disability Index, and the physical component summary in all diagnostic groups had improved significantly already by 3 months of follow-up, and the improvement remained stable until 2 years of follow-up. Interestingly, the biggest improvement in Oswestry Disability Index (-27), physical component summary (13) and SF-6D (0.19) was found in a group with disc pathology. The mental component summary score values were similar preoperatively (P = 85), and the improvement in the mental component summary was significant in the groups with degenerative olisthesis, spinal stenosis, and postoperative conditions.

CONCLUSION

The 5 surgical indication groups showed significantly different scores preoperatively in health utility, disability, and the physical aspect of HRQOL. At 2 years, however, all groups benefitted from the fusion surgery significantly.

LEVEL OF EVIDENCE

3.

Total hospital costs of surgical treatment for adult spinal deformity: an extended follow-up study

BACKGROUND CONTEXT

Whereas the costs of primary surgery, revisions, and selected complications for adult spinal deformity (ASD) have been individually reported in the literature, the total costs over several years after surgery have not been assessed. The determinants of such costs are also not well understood in the literature.

PURPOSE

This study analyzes the total hospital costs and operating room (OR) costs of ASD surgery through extended follow-up.

STUDY DESIGN/SETTING

Single-center retrospective analysis of consecutive surgical patients.

PATIENT SAMPLE

Four hundred eighty-four consecutive patients undergoing surgical treatment for ASD from January 2005 through January 2011 with minimum three levels fused.

OUTCOME MEASURES

Costs were collected from hospital administrative data on the total hospital costs incurred for the operation and any related readmissions, expressed in 2010 dollars and discounted at 3.5% per year. Detailed data on OR costs, including implants and biologics, were also collected.

METHODS

We performed a series of paired t tests and Wilcoxon signed-rank tests for differences in total hospital costs over different follow-up periods. The goal of these tests was to identify a time period over which average costs plateau and remain relatively constant over time. Generalized linear model regression was used to estimate the effect of patient and surgical factors on hospital inpatient costs, with different models estimated for different follow-up periods. A similar regression analysis was performed separately for OR costs and all other hospital costs.

RESULTS

Patients were predominantly women (n=415 or 86%) with an average age of 48 (18-82) years and an average follow-up of 4.8 (2-8) years. Total hospital costs averaged $120,394, with primary surgery averaging $103,143 and total readmission costs averaging $67,262 per patient with a readmission (n=130 or 27% of all patients). Operating room costs averaged $70,514 per patient, constituting the majority (59%) of total hospital costs. Average total hospital costs across all patients significantly increased (p<.01) after primary surgery, from $111,807 at 1-year follow-up to $126,323 at 4-year follow-up. Regression results also revealed physician preference as the largest determinant of OR costs, accounting for $14,780 of otherwise unexplained OR cost differences across patients, with no significant physician effects on all other non-OR costs (p<.05).

CONCLUSIONS

The incidence of readmissions increased the average cost of ASD surgery by more than 70%, illustrating the financial burden of revisions/reoperations; however, the cost burden resulting from readmissions appeared to taper off within 5 years after surgery. The estimated impact of physician preference on OR costs also highlights the variation in current practice and the opportunity for large cost reductions via a more standardized approach in the use of implants and biologics.

Post-traumatic stress symptoms after elective lumbar arthrodesis are associated with reduced clinical benefit

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To assess the impact of postoperative post-traumatic stress disorder (PTSD) symptoms on clinical outcomes after lumbar arthrodesis.

SUMMARY OF BACKGROUND DATA

Postoperative PTSD symptoms occur among many patients who underwent elective lumbar fusion. Although adverse impact of preoperative depression and psychiatric distress has been described, no reports have assessed the impact of postoperative PTSD symptoms on clinical outcomes after lumbar arthrodesis.

METHODS

Seventy-three patients undergoing elective lumbar spinal arthrodesis completed the PTSD Checklist-Civilian Version (PCL-C) at 3, 6, 9, and 12 months postoperatively. Short-Form 36 and the Oswestry Disability Index (ODI) were completed preoperatively and at 1 year postoperatively. Impact of postoperative PTSD symptoms, preoperative psychiatric diagnoses, and mental composite scores on clinical outcome scores and likelihood of reaching minimal clinically important difference for ODI and physical composite score (PCS) was evaluated.

RESULTS

PTSD symptoms were reported in 22% of the cohort, with significantly reduced surgical benefit as measured by final (P < 0.0001 and P = 0.003) and total change (P = 0.013 and P = 0.032) in ODI and PCS scores, respectively. Likelihood of reaching minimal clinically important difference for both ODI and PCS was also reduced for patients reporting PTSD symptoms (P = 0.009 and P = 0.001, respectively). A preoperative psychiatric diagnosis correlated only with final ODI score (P = 0.008). Preoperative mental composite scores were significantly correlated with final ODI and PCS scores, as well as final change from preoperative and likelihood of reaching minimal clinically important difference for PCS, but not for ODI scores.

CONCLUSION

Postoperative psychological distress was strongly correlated with reduced clinical benefit among patients who underwent elective lumbar arthrodesis, and seemed to be a stronger predictor of reduced clinical benefit than either major psychiatric diagnosis or preoperative mental composite scores. Efforts to reduce postoperative psychological distress may offer an opportunity to enhance patient reported clinical outcomes from elective spine surgery.

LEVEL OF EVIDENCE

2.

Prevalence of adjacent segment degeneration after spine surgery: a systematic review and meta-analysis

STUDY DESIGN

Systematic review of published prevalence of adjacent segment degeneration (ASD) after spine surgery.

OBJECTIVE

To evaluate the prevalence of ASD in patients after cervical and lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

ASD is a common complication after spine surgery in long-term follow-up. A large body of literature has been reported on the topic, but no meta-analysis of the epidemiological data on ASD has been published

METHODS

We searched the MEDLINE until March 2012 published in English language that reported the prevalence of ASD after spine surgery. We determined the ASD rates by calculating proportions and 95% confidence interval (CI) for each study and then pooled the data to derive a pooled proportion and 95% CI.

RESULTS

A total of 94 studies with 34,716 patients from 19 countries were included. The occurrence of radiograph ASD ranged from 4.8% to 92.2%, and the pooled prevalence was 29.3% (95% CI, 22.7%-35.8%) by the random-effects model. The occurrence of symptoms ASD ranged from 0.0% to 30.3%, and the pooled prevalence was 7.4% (95% CI, 6.4%-8.5%). In cervical position, the occurrence of radiograph ASD and symptoms ASD was 32.8% (95% CI, 17.8%-47.9%) and 6.3% (95% CI, 4.8%-7.8%); in lumbar position, the occurrence of radiograph ASD and symptoms ASD was 26.6% (95% CI, 21.3%-31.9%) and 8.5% (95% CI, 6.4%-10.7%). In the 0.5- to 2- or less, more than 2- to 5- or less, and more than 5- to 20- or less year diagnosis time, the radiograph ASD prevalence was 21.8% (16.0%-27.6%), 33.6% (21.8%-45.4%), and 37.4% (10.7%-64.1%), respectively; and the symptoms ASD prevalence was 6.5% (4.8%-8.1%), 12.1% (8.2%-16.0%), and 3.2% (2.5%-4.0%), respectively.

CONCLUSION

Spine surgery is associated with significant risk of ASD. These figures may be useful in the estimation of the burden of the ASD after spine surgery.

Differentiating minimum clinically important difference for primary and revision lumbar fusion surgeries

OBJECT

Previous studies have reported on the minimum clinically important difference (MCID), a threshold of improvement that is clinically relevant for lumbar degenerative disorders. Recent studies have shown that pre- and postoperative health-related quality of life (HRQOL) measures vary among patients with different diagnostic etiologies. There is also concern that a patient's previous care experience may affect his or her perception of clinical improvement. This study determined if MCID values for the Oswestry Disability Index (ODI), 36-Item Short-Form Health Survey (SF-36), and back and leg pain are different between patients undergoing primary or revision lumbar fusion.

METHODS

Prospectively collected preoperative and 1-year postoperative patient-reported HRQOLs, including the ODI, SF-36 physical component summary (PCS), and numeric rating scales (0-10) for back and leg pain, in patients undergoing lumbar spine fusion were analyzed. Patients were grouped into either the primary surgery or revision group. As the most widely accepted MCID values were calculated from the minimum detectable change, this method was used to determine the MCID.

RESULTS

A total of 722 patients underwent primary procedures and 333 patients underwent revisions. There was no statistically significant difference in demographics between the groups. Each group had a statistically significant improvement at 1 year postoperatively compared with baseline. The minimum detectable change-derived MCID values for the primary group were 1.16 for back pain, 1.36 for leg pain, 12.40 for ODI, and 5.21 for SF-36 PCS. The MCID values for the revision group were 1.21 for back pain, 1.28 for leg pain, 11.79 for ODI, and 4.90 for SF-36 PCS. These values are very similar to those previously reported in the literature.

CONCLUSIONS

The MCID values were similar for the revision and primary lumbar fusion groups, even when subgroup analysis was done for different diagnostic etiologies, simplifying interpretation of clinical improvement. The results of this study further validate the use of patient-reported HRQOLs to measure clinical effectiveness, as a patient's previous experience with care does not seem to substantially alter an individual's perception of clinical improvement.