Failure of nonoperative care in adult symptomatic lumbar scoliosis: incidence, timing, and risk factors for conversion from nonoperative to operative treatment.

OBJECTIVE: The Adult Symptomatic Lumbar Scoliosis (ASLS) study is a prospective multicenter trial with randomized and observational cohorts comparing operative and nonoperative treatment for ASLS. The objective of the present study was to perform a post hoc analysis of the ASLS trial to examine factors related to failure of nonoperative treatment in ASLS. METHODS: Patients from the ASLS trial who initially received at least 6 months of nonoperative treatment were followed for up to 8 years after trial enrollment. Baseline patient-reported outcome measures (Scoliosis Research Society-22 [SRS-22] questionnaire and Oswestry Disability Index), radiographic data, and other clinical characteristics were compared between patients who did and did not convert to operative treatment during follow-up. The incidence of operative treatment was calculated and independent predictors of operative treatment were identified using multivariate regression. RESULTS: Of 135 nonoperative patients, 42 (31%) crossed over to operative treatment after 6 months and 93 (69%) received only nonoperative treatment. In the observational cohort, 23 (22%) of 106 nonoperative patients crossed over to surgery. In the randomized cohort, 19 (66%) of 29 patients randomized to nonoperative treatment crossed over to surgery. The most impactful factors associated with crossover from nonoperative to operative treatment were enrollment in the randomized cohort and baseline SRS-22 subscore < 3.0 at the 2-year follow-up, closer to 3.4 at 8 years. In addition, baseline lumbar lordosis (LL) < 50° was associated with crossover to operative treatment. Each 1-point decrease in baseline SRS-22 subscore was associated with a 233% higher risk of conversion to surgery (hazard ratio [HR] 2.33, 95% confidence interval [CI] 1.14-4.76, p = 0.0212). Each 10° decrease in LL was associated with a 24% increased risk of conversion to operative treatment (HR 1.24, 95% CI 1.03-1.49, p = 0.0232). Enrollment in the randomized cohort was associated with a 337% higher probability of proceeding with operative treatment (HR 3.37, 95% CI 1.54-7.35, p = 0.0024). CONCLUSIONS: Enrollment in the randomized cohort, a lower baseline SRS-22 subscore, and lower LL were associated with conversion from nonoperative treatment to surgery in patients (observational and randomized) who were initially managed nonoperatively in the ASLS trial.

Effect modifiers for patient-reported outcomes in operatively and nonoperatively treated patients with adult symptomatic lumbar scoliosis: a combined analysis of randomized and observational cohorts.

OBJECTIVE: Adult symptomatic lumbar scoliosis (ASLS) is a common and disabling condition. The ASLS-1 was a multicenter, dual-arm study (with randomized and observational cohorts) examining operative and nonoperative care on health-related quality of life in ASLS. An aim of ASLS-1 was to determine patient and radiographic factors that modify the effect of operative treatment for ASLS. METHODS: Patients 40-80 years old with ASLS were enrolled in randomized and observational cohorts at 9 North American centers. Primary outcomes were the differences in mean change from baseline to 2-year follow-up for the SRS-22 subscore (SRS-SS) and the Oswestry Disability Index (ODI). Analyses were performed using an as-treated approach with combined cohorts. Factors examined were prespecified or determined using regression tree analysis. For each potential effect modifier, subgroups were created using clinically relevant cutoffs or via regression trees. Estimates of within-group and between-group change were compared using generalized linear mixed models. An effect modifier was defined as a treatment effect difference greater than the minimal detectable measurement difference for both SRS-SS (0.4) and ODI (7). RESULTS: Two hundred eighty-six patients were enrolled and 256 (90%) completed 2-year follow-up; 171 received operative treatment and 115 received nonoperative treatment. Surgery was superior to nonoperative care for all effect subgroups considered, with the exception of those with nearly normal pelvic incidence-lumbar lordosis (PI-LL) match (≤ 11°). Male patients and patients with more (> 11°) PI-LL mismatch at baseline had greater operative treatment effects on both the SRS-SS and ODI compared to nonoperative treatment. No other radiographic subgroups were associated with treatment effects. High BMI, lower socioeconomic status, and poor mental health were not related to worse outcomes. CONCLUSIONS: Numerous factors previously related to poor outcomes with surgery, such as low mental health, lower socioeconomic status, and high BMI, were not related to outcomes in ASLS in this exploratory analysis. Those patients with higher PI-LL mismatch did improve more with surgery than those with normal alignment. On average, none of the factors considered were associated with a worse outcome with operative treatment versus nonoperative treatment. These findings may guide future prospective analyses of factors related to outcomes in ASLS care.

Vastus lateralis strain associated with patellofemoral pain syndrome: a report of 2 cases.

Muscle strains of the quadriceps group are common, and occur mostly in the rectus femoris. Strains occur most often when muscles are suddenly activated while on stretch, during either eccentric or concentric contraction. We report 2 cases of vastus lateralis strain that occurred in association with clinical histories of patellofemoral pain syndrome. Symptoms described included anterior knee pain associated with prolonged sitting with the knee flexed, and anterior knee pain associated with running, stair climbing, and jumping. These symptoms preceded the acute strain by at least 1 year. These cases emphasize a clinician's need to understand knee biomechanics, and the need to consider the entire kinetic chain when managing pain and injury in an extremity.