Success treating AIS with bracing is related to time worn and scoliosis severity. Temperature monitoring can help patients comply with their orthotic prescription. Routinely collected temperature data from the start of first brace treatment was reviewed for 14 patients. All were female with an average age of 12.4 years (range 10.3–14.6) and average 49o Cobb angle (30–64).

Our current service recommendation is brace wear for 20 hours a day. Patients complied with this prescription 38.0% of the time, with four patients averaging this or more. Average brace wear was 16.3 hours per day (3.5–22.2).

There were 13 patients who had completed brace treatment. The majority had surgery (7/13; 54%) or were considering surgery (1/13; 8%). There were 5 who did not wish surgery at discharge (5/13; 38%); 1 achieved a 40o Cobb angle, with 4 larger (53o;53o;54o;68o). The Bracing in AIS Trial (BrAIST) study measured “success” as less than a 50o Cobb angle, so using this metric our cohort has had a single “success”.

Temperature monitors allowed an analysis of when patients were achieving their brace wear. When comparing daywear (8am-8pm) to nightwear (8pm-8am), patients wore their brace an average of 7.6 hours a day (2.5–11.2) and 8.7 hours a night (0.4–11.5).

We conclude the minority of our patients comply with our current 20 hour orthotic prescription. The “success” of brace treatment is lower than comparison studies despite higher average compliance but starting with a larger scoliosis. Brace wear is achieved during both the day and night.

Lowest instrumented vertebra (LIV) selection is critical to preventing complications following posterior spinal arthrodesis (PSA) for thoracolumbar/lumbar adolescent idiopathic scoliosis (TL/L AIS), but evidence guiding LIV selection is limited.

This study aimed to investigate the efficacy of PSA using novel unilateral convex segmental pedicle screw instrumentation (UCS) in correcting TL/L AIS, to identify radiographic parameters correlating with distal extension of PSA, and to develop a predictive equation for distal fusion extension using these parameters.

We reviewed data (demographic, clinical, radiographic, and SRS-22 questionnaires) preoperatively to 2-years' follow-up for TL/L AIS patients treated by PSA using UCS between 2006 to 2011. 53 patients were included and divided into 2 groups: Group-1 (n=36) patients had PSA between Cobb-to-Cobb levels; Group-2 (n=17) patients required distal fusion extension.

A mean curve correction of 80% was achieved. Mean postoperative LIV angle, TL/L apical vertebra translation (AVT), and trunk shift were lower than previous studies. Six preoperative radiographic parameters significantly differed between groups and correlated with distal fusion extension: thoracic curve size, thoracolumbar curve size, LIVA, AVT, lumbar flexibility index, and Cobb angle on lumbar convex bending. Regression analysis optimised an equation (incorporating the first five parameters) which is 81% accurate in predicting Cobb-to-Cobb fusion or distal extension. SRS-22 scores were similar between groups.

We conclude that TL/L AIS is effectively treated by PSA using UCS, six radiographic parameters correlate with distal fusion extension, and a predictive equation incorporating these parameters reliably informs LIV selection and the need for fusion extension beyond the caudal Cobb level.