Minimum clinically important difference of the health-related quality of life scales in adult spinal deformity calculated by latent class analysis: is it appropriate to use the same values for surgical and nonsurgical patients?

BACKGROUND CONTEXT: Health-related quality of life (HRQOL) parameters have been shown to be reliable and valid in patients with adult spinal deformity (ASD). Minimum clinically important difference (MCID) has become increasingly important to clinicians in evaluating patients with a threshold of improvement that is clinically relevant. PURPOSE: To calculate MCID and minimum detectable change (MDC) values of total scores of the Core Outcome Measures Index (COMI), Oswestry Disability Index (ODI), Physical Component Summary (PCS), Mental Component Summary (MCS) of the Short Form 36 (SF-36), and Scoliosis Research Society 22R (SRS-22R) in surgically and nonsurgically treated ASD patients who have completed an anchor question at pretreatment and 1-year follow-up. STUDY DESIGN/SETTING: Prospective cohort. PATIENT SAMPLE: Surgical and nonsurgical patients from a multicenter ASD database. OUTCOME MEASURES: Self-reported HRQOL measures (COMI, ODI, SF-36, SRS-22R, and anchor question). METHODS: A total of 185 surgical and 86 nonsurgical patients from a multicenter ASD database who completed pretreatment and 1-year follow-up HRQOL scales and the anchor question at the first year follow-up were included. The anchor question was used to determine MCID for each HRQOL measure. MCIDs were calculated by an anchor-based method using latent class analysis (LCA) and MDCs by a distribution-based method. RESULTS: All differences between means of baseline and first year postoperative total score measures for all scales demonstrated statistically significant improvements in the overall population as well as the surgically treated patients but not in the nonsurgical group. The calculated MDC and MCID values of HRQOL parameters in the entire study population were 1.34 and 2.62 for COMI, 10.65 and 14.31 for ODI, 6.09 and 7.33 for SF-36 PCS, 6.14 and 4.37 for SF-36 MCS, and 0.42 and 0.71 for SRS-22R. The calculated MCID values for surgical and non-surgical treatment groups were 2.76 versus 1.20 for COMI, 14.96 versus 2.45 for ODI, 7.83 versus 2.15 for SF-36 PCS, 5.14 versus 2.03 for SF-36 MCS, and 0.94 versus 0.11 for SRS-22R; the MDC values for surgical and nonsurgical treatment groups were 1.22 versus 1.51 for COMI, 10.27 versus 9.45 for ODI, 5.16 versus 6.77 for SF-36 PCS, 6.05 versus 5.67 for SF-36 MCS, and 0.38 versus 0.43 for SRS-22R. CONCLUSIONS: This study has demonstrated that MCID calculations for the HRQOL scales in ASD using LCA yield values comparable to other studies that had used different methodologies. The most important finding was the significantly different MCIDs for COMI, ODI, SF-36 PCS and SRS-22 in the surgically and nonsurgically treated cohorts. This finding suggests that a universal MCID value, inherent to a specific HRQOL for an entire cohort of ASD may not exist. Use of different MCIDs for surgical and nonsurgical patients may be warranted.

Impact of early unanticipated revision surgery on health-related quality of life after adult spinal deformity surgery.

BACKGROUND CONTEXT: Revision surgery represents a major event for patients undergoing adult spinal deformity (ASD) surgery. Previous reports suggest that ASD surgery has minimal or no impact on health-related-quality of life (HRQOL) outcomes. PURPOSE: The present study aims to investigate the impact of early reoperations within the first year on HRQOL and on the likelihood of reaching the minimally clinically important difference (MCID) after ASD surgery. DESIGN: This is a retrospective analysis of prospectively collected data from consecutive surgically treated adult deformity surgery patients included in a multicenter, international database. PATIENT SAMPLE: The present study included 280 patients from a multicenter international prospective database. OUTCOME MEASURE: Oswestry Disability Index (ODI), Short Form-36 (SF-36), Scoliosis Research Society-22 (SRS-22), MCID were evaluated in this work. METHODS: Consecutive surgical patients with ASD recruited prospectively in six different centers from four countries with a minimum 2-year follow-up were stratified into two groups: R (revision surgery within the first year) and NR (no revision). Health-related-quality of life (ODI, SF-36, SRS-22) was assessed and compared at 6-month, 1-year, and 2-year follow-up stages. Statistical analysis included chi-square tests, Student t tests, and linear mixed models. RESULTS: Forty-three patients (R Group) received 46 revision surgeries. Nineteen patients (41.3%) had implant-related complications, 9 patients (19.6%) had deep surgical site infections, 9 patients (19.6%) had proximal junctional kyphosis, 3 patients (6.5%) had hematoma, and 6 patients (13%) had other complications. Baseline characteristics differed between groups. At 6 months, all HRQOL scores improved in both groups, except in the SF-36 Mental Component Summary and SRS-22 mental health domain in the R Group. At 1 year, ODI and SRS-22 improvement was significantly greater in the NR Group, exceeding the reported MCID. At the 2-year follow-up, ODI, SRS-22, SF-36 MCS, and SF-36 PCS improvement was similar in both groups. However, postoperative change was only above the MCID for SF-36 PCS, ODI, and SRS-22 in the NR Group. CONCLUSIONS: Early unanticipated revision surgery has a negative impact on mental health at 6 months and reduces the chances of reaching an MCID improvement in SRS-22, SF-36 PCS, and ODI at the 2-year follow-up.

The Adult Deformity Surgery Complexity Index (ADSCI): a valid tool to quantify the complexity of posterior adult spinal deformity surgery and predict postoperative complications.

BACKGROUND CONTEXT: In 2008, Mirza et al. designed and validated the first and only index capable of quantifying the complexity of spine surgery. However, this index is not fully applicable to adult spinal deformity (ASD) surgery as it does not include the surgical techniques most commonly used and most strongly associated with perioperative complications in patients with ASD. PURPOSE: The objective of this study is to develop an "Adult Deformity Surgery Complexity Index" (ADSCI) to quantify objectively the complexity of the ASD posterior surgery. STUDY DESIGN/SETTING: This is an expert consensus (Delphi process) and retrospective analysis of prospectively collected data using multiple regression models. PATIENT SAMPLE: Patients were prospectively enrolled in two comparable multicenter ASD databases sharing the same inclusion criteria. OUTCOME MEASURES: The ADSCI was internally and externally validated using R2 for intraoperative bleeding and length of surgery. Receiver operating characteristics (ROC) and area under the curve (AUC) analysis was used to assess the sensitivity and specificity of ADSCI. METHODS: The development and validation of ADSCI was based on the construction and comparison of three different tools: ADSCI score was constructed by three rounds of expert consensus (ADSCI-Delphi) and two multiple regression models (ADSCI-RM-Simple and ADSCI-RM-Mixed). Their predictive capability was compared by means of R2 values in the same subrogated of surgical complexity as in the Mirza index validation: intraoperative bleeding and duration of surgery. Sensitivity and specificity were evaluated using ROC curves and AUC analysis. The external validity was also examined by evaluating its predictive capability in another multicenter ASD database of comparable patients in the United States. RESULTS: At the time of the study, the database included 1,325 patients. Four hundred seventy-five patients were eligible for the study, having been treated surgically using a posterior approach only (52.2 years standard deviation 20; 77.7% women; 85.4% American Society of Anesthesiologists I/II). Fifty-one international experts participated in the Delphi consensus process. The surgical variables selected by consensus and included in the equation were divided into actions and factors. Actions selected were number of fused segments, decompressions, interbody fusions, and cemented levels; number and type of posterior osteotomies; and use of pelvic fixation. The factors included were implant density, revision surgery, and team experience. ADSCI-RM-Mixed (regression model with Delphi formula interactions) provided the best estimates and predictive value, well above Mirza's invasiveness index. The ADSCI-RM-Mixed, with greater AUCs (>0.70), was also the most sensitive and specific for both of the dependent variables studied and for complication prediction. ADSCI-RM-Mixed obtained also the highest R2 value in the validation cohort in predicting blood loss (R2=0.34) and surgical time (R2=0.26) with effect sizes similar to those for the derivation cohort. CONCLUSIONS: The ADSCI is the first tool to be specifically developed for the preoperative assessment of the complexity of ASD surgery. This study confirms its validity, specificity, and sensitivity, and shows that it has greater predictive capability than the more generic Mirza invasiveness index. The ADSCI should be useful for quantitatively estimating the increased risk associated with more invasive surgery and adjusting for surgical case-mix when making safety comparisons in ASDS.

Decision analysis to identify the ideal treatment for adult spinal deformity: What is the impact of complications on treatment outcomes?

OBJECTIVE: The aim of this study was to analyze the impact of treatment complications on outcomes in adult spinal deformity (ASD) using a decision analysis (DA) model. METHODS: The study included 535 ASD patients (371 with non-surgical (NS) and 164 with surgical (S) treatment) from an international multicentre database of ASD patients. DA was structured in two main steps; 1) Baseline analysis (Assessing the probabilities of outcomes, Assessing the values of preference -utilities-, Combining information on probability and utility and assigning the quality adjusted life expectancy (QALE) for each treatment) and 2) Sensitivity analysis. Complications were analyzed as life threatening (LT) and nonlife threatening (NLT) and their probabilities were calculated from the database as well as a thorough literature review. Outcomes were analyzed as improvement, no change and deterioration. Death/complete paralysis was considered as a separate category. RESULTS: All 535 patients were analyzed in regard to complications. Overall, there were 78 NLT and 12 LT complications and 3 death/paralysis. Surgical treatment offered significantly higher chances of clinical improvement but also was significantly more prone to complications (31.7% vs. 11.1%, p < 0.001). CONCLUSION: Surgical treatment of ASD is more likely to cause complications compared to NS treatment. On the other hand, surgery has been shown to provide a higher likelihood of improvement in HRQoL scores. So, the decision on the type of treatment in ASD needs to take both chances of improvement and burden associated with S or NS treatments and better be arrived by the active participation of patients and physicians equipped with the present information. LEVEL OF EVIDENCE: Level II, Decision analysis.

Does Surgery for Adult Spinal Deformity Affect the Cognitive Abilities in Patients over 50 Years of Age?

AIM: To analyze the cognitive abilities of older patients undergoing spinal deformity surgery so as to understand whether adult spinal deformity (ASD) surgery is associated with postoperative cognitive malfunction. MATERIAL AND METHODS: A prospective longitudinal study was performed on surgical patients older than 50 years, enrolled in a prospective multicenter database. Mini-mental state examination (MMSE) was performed to assess cognitive function in addition to the health-related quality of life (HRQOL) tests; (SF-36, ODI and SRS-22) at the pre-operative, post-operative 6 weeks and 6 months points. Demographics, preoperative health status, co-morbidities and surgical characteristics were also analyzed. Descriptive statistics and repeated measures of variance analysis were performed. RESULTS: A total of 90 patients with a mean age of 67.4±8.2 years were enrolled in the study; all had MMSE evaluations at 6 weeks follow-up and 58 patients had both 6 weeks and 6 months follow-up. Average (SD) surgical time, estimated blood loss, number of levels fused and hospital stay were 240.1 (111.9) minutes, 1621.2 (1058.7) ml, 11.2 (4.4) levels and 14.2 (11.45) days, respectively. On analysis, a slight increase in mean MMSE score (p > 0.05) between time points was found despite decreases of > 2 points (3 or 4) in 6 patients (6.7%) at both time points. CONCLUSION: Although ASD surgery in older patients is recognized as challenging, this study suggests that it is not necessarily associated with a significant deterioration in the cognitive abilities of patients undergoing surgery. This may be due to the relatively minor influence of ASD itself on the cognitive abilities of the patients involved as well as to the relatively stable hemodynamic conditions obtainable during modern ASD surgery.

Adult spinal deformity: a very heterogeneous population of patients with different needs.

OBJECTIVE: The purpose of this study was to analyze and demonstrate the heterogeneity in adult spinal deformity (ASD) populations by baseline health-related quality of life (HRQL) data. METHODS: ASD was defined as patients over 18 years of age with any of the following: coronal deformity >20°, sagittal vertical axis (SVA) >5 cm, pelvic tilt >25°, or thoracic kyphosis >60°. Three hundred fifty-two patients meeting the above definition of ASD were analyzed for measures of HRQL (Oswestry disability index [ODI], SRS-22 [Scoliosis Research Society-22], and SF-36 [Short form-36 health survey] questionnaires) at presentation. Age groups were defined as 18-40, 40-60, and >60 years. Deformity was analyzed as either degenerative (DS) or idiopathic (IS) (294 patients; 71 degenerative, 223 idiopathic). RESULTS: There were significant differences between age groups--predominantly between the lower age group (18-40) and others--for all HRQL parameters except SRS-22 mental health and SF-36 mental component score. Similarly, HRQL measures for DS and IS deformities were significantly different. Regarding location of main curves, thoracolumbar/lumbar (TL/L) (70.2%) was dominant for the DS group and thoracic (55%) for the IS group. Mean age was 65 years for the DS group and 36 for the IS group, which were significantly different. Radiographic parameters were also significantly different between these groups, with IS patients having more coronal deformity and better sagittal balance. CONCLUSION: ASD patients are very heterogeneous at presentation, depending on age and diagnosis. There is a distinct need to stratify ASD as early and late presentation ASD and/or by diagnosis. Patients with IS deformity may be very different from those with DS deformity, even at time of presentation. These differences must be taken into consideration in treatment of these patients, as well as for the analysis of the results of treatment.

A decision analysis to identify the ideal treatment for adult spinal deformity: is surgery better than non-surgical treatment in improving health-related quality of life and decreasing the disease burden?

BACKGROUND: Adult spinal deformity (ASD) is a major public health problem. There are pros and cons of the available treatment alternatives (surgical or non-surgical) and it had been difficult to identify the best treatment modality. AIM: To construct a statistical DA model to identify the optimum overall treatment in ASD. METHODS: From an international multicentre database of ASD patients (968 pts), 535 who had completed 1 year follow-up (371 non-surgical-NS, 164 surgical-S), constitute the population of this study. DA was structured in two main steps of: (1) baseline analysis (assessing the probabilities of outcomes, assessing the values of preference-utilities-, combining information on probability and utility and assigning the quality adjusted life expectancy (QALE) for each treatment) and (2) sensitivity analysis. RESULTS: Four hundred and thirty-two patients (309 NS, 123 S) had baseline and 1 year follow-up ODI measurements. Overall, 104 (24.1 %) were found to be improved (a decrease in ODI > 8 points), 225 (52.1 %) unchanged (-8 > ODI > 8) and 65 deteriorated. Surgery presented with a higher chance of improvement (54.2 %) versus NS (9.7 %). The overall QALE ranged from 56 to 69 (of 100 years) and demonstrated better final QALE in the NS group (60 vs. 65, P = 0.0038), this group having started with higher QALE as well (56 vs. 65 years, P < 0.0001). There were improvements in overall QALE in both groups but this was significant only in the surgical group (S from 56 to 60 years, P < 0.0001; NS from 65 to 65 years, P = 0.27). In addition, in the subgroup of patients with significant baseline disability (ODI > 25) surgery appeared to yield marginally better final QALE (58 vs. 56 years, P = 0.1) despite very a similar baseline (54 vs. 54 years, P = 0.93). DISCUSSION AND CONCLUSIONS: This study demonstrated that a single best treatment modality for ASD may not exist. Conservative treatment appears to yield higher (up to 6 %) QALE compared to surgery, most probably secondary to a higher baseline QALE. On the other hand, surgery provides a significantly higher increase in QALE. Especially in patients with significant disability at baseline, the final QALE tended higher in the S group (although not significant). Finally, chances of a relevant improvement at first year turned out to be significantly lower with NS treatment.

Multiple Regression Analysis of Factors Affecting Health-Related Quality of Life in Adult Spinal Deformity.

BACKGROUND: Previous studies demonstrated the adult spinal deformity (ASD) population is heterogeneous. Multiple parameters may affect health-related quality of life (HRQL). AIM: To understand the ranking of parameters affecting HRQL in ASD using multiple regression analysis. PATIENTS AND METHODS: A total of 483 patients enrolled in a prospective multicenter ASD database from the population. Multiple regression analysis was performed for Scoliosis Research Society-22 (SRS-22) and Oswestry Disability Index (ODI) separately. Initially proposed primary variables of diagnosis (highest correlation), age, lordosis gap (L gap), and coronal curve location were regressed for each response variable (SRS-22 and ODI) univariately. Age and L gap could not be used together because of high colinearity. Coronal curve location was removed owing to an insignificant correlation. Two initial models were considered per response, consisting of diagnosis and age in one and diagnosis and L gap in the other. The rest of the potentially predictive variables were introduced in these models one at a time. Final models were evaluated using stepwise automatic model selection. RESULTS: For ODI, body mass index (BMI), gender, and sagittal and spinopelvic parameters were in the basic model but only BMI and gender in the model with L gap and only gender in the model with age were highly predictive. For SRS-22, a large number of parameters were in the basic model but BMI, gender, coronal balance, lordosis curve, and sagittal vertical axis in the model with L gap and only gender in the model with age were highly predictive. Coronal curve location was not significantly predictive in any model. CONCLUSIONS: These findings reiterate the importance of patient diagnosis, age, and/or the amount of lordosis as the most important factors affecting HRQL in ASD. Gender, BMI, and sagittal vertical axis appear to be consistently important co-variables whereas coronal balance and magnitude of L curves may also be important in SRS-22. These may aid in better understanding the problem in ASD and may be useful in future classifications.

Impact on health related quality of life of adult spinal deformity (ASD) compared with other chronic conditions.

PURPOSE: Medical and health policy providers should be aware of the impact of adult spinal deformity (ASD) on health-related quality of life (HRQL). The purpose of this study was to compare the relative burden of four chronic conditions with that of ASD. METHODS: The International Quality of Life Assessment project gathered data from 24,936 people and published the SF-36 scores of patients with self-reported arthritis, chronic lung disease, diabetes and congestive heart failure from 8 industrialized countries (3 continents) Alonso et al. (Qual Life Res Int J Qual Life Asp Treat Care Rehabil 13:283-298, 2004). We compared these with the SF-36 baseline data of consecutive patients with ASD enrolled in a prospective multicentre international database with the following inclusion criteria: age >18 years and scoliosis >20°, sagittal vertical axis >5 cm, pelvic tilt >25° or thoracic kyphosis >60°. Four ASD groups were considered: all ASD patients, surgical candidates (preop HRQL scores), and non-surgical candidates with and without previous surgery. Adjusted estimates of the impact of chronic disease were calculated using separate multivariate linear regression models. Individuals without chronic conditions were used as the reference group. Coefficients for each chronic condition and ASD represent the difference compared with this healthy group. RESULTS: 766 patients (mean age 45.8 years) met the inclusion criteria for ASD. The scores on all SF-36 domains were lower in ASD patients than in any other chronic condition. Differences between ASD and the other chronic conditions were always greater than the reported minimal clinically important differences. When compared with individuals reporting no medical conditions, SF-36 scores from the population with self-reported chronic conditions ranged from -2.5 to -14.1. Comparable scores for patients with ASD ranged from -10.9 to -45.0. Physical function, role physical and pain domains showed the worst scores. Surgical candidates with ASD displayed the worst HRQL scores (-17.4 to -45.0) and patients previously operated the best (-10.9 to -33.3); however, even the latter remained worse than any scores for the other self-reported chronic conditions. CONCLUSIONS: The global burden of ASD was huge compared with other self-reported chronic conditions in the general population of eight industrialized countries. The impact of ASD on HRQL warrants the same research and health policy attention as other important chronic diseases.

Is Routine Postoperative Radiologic Follow-up Justified in Adolescent Idiopathic Scoliosis?

STUDY DESIGN: Retrospective review. OBJECTIVES: To determine whether routine periodic radiographic examination is worthwhile in adolescent idiopathic scoliosis (AIS) patients undergoing instrumented fusion with third-generation implants. SUMMARY OF BACKGROUND DATA: In common practice, patients who have undergone surgery for idiopathic scoliosis are followed up for a minimum of 2 years by clinical assessment and routine radiographic study at 3, 6, 12, and 24 months. The radiation related to these examinations is not negligible. To our knowledge, the use of routine radiographic follow-up after posterior spinal fusion for adolescent idiopathic scoliosis has not been evaluated. METHODS: We retrospectively analyzed full-spine X-rays and clinical records from the first 2 postoperative years of 43 patients. We sought any clinical feature (eg, pain, deformity progression, material protrusion) justifying X-ray, and any relevant radiologic finding (eg, loss of correction, instrumentation loosening, junctional kyphosis). RESULTS: Excluding the immediate postoperative films, 14.8% of X-rays were clinically justified, 8.3% were associated with a relevant finding, and 4.3% led to a therapy change. All patients with clinical deformity progression had a relevant X-ray finding. Pain was associated with a relevant finding in 23.5% of cases (positive predictive value, 0.1); 7.4% of films with no clinical justification showed a relevant finding (negative predictive value, 0.86). Lower Risser sign increased the risk of having a relevant radiographic finding (p < .05). CONCLUSIONS: With the current use of third-generation implants, routine biplanar postoperative X-rays at 3, 6, 12, and 24 months do not seem to be justified in AIS and should be avoided in mature, asymptomatic patients.