This research looked at the technical difficulties and results of sacral-alar-iliac (SAI) fixation for scoliosis in individuals who had undergone a pelvic osteotomy for hip dysplasia. Scoliosis and hip dislocation are 2 conditions commonly seen in patients with the neuromuscular illness. One may be affected by the other if both are surgically corrected. 

Researchers looked at medical records of individuals younger than 18 years old who had a pelvic osteotomy followed by spinal fusion using SAI screws and a follow-up period of more than or equal to 2 years. They noted the size of the SAI screws used, how long it took to execute the osteotomy and SAI fixation, what kind of osteotomy was performed, and whether or not there were any difficulties. The data was analyzed using a pairwise comparison, and the significance level was set at p-value  less than 0.05. 

There were 32 patients in total. The typical age for a pelvic osteotomy was 10.3±3.2 years, while the typical age for SAI fixing was 13.5±3.4 years. The majority of patients received a Dega osteotomy on only one side of their body (78.1%). The osteotomy side typically had smaller screws (66 mm vs. 72 mm, P<0.05). Due to pelvic deformity from the pelvic osteotomy, SAI screw placement was technically problematic in 8 individuals (25%). Locating the intracortical canal required the use of a bent awl. There were no SAI screw-related problems and no statistically significant differences in the degrees to which pelvic obliquity and major coronal curves were corrected. About 2 patients (6.3%), both of whom had no clinical complaints, showed screw lucency of more than 2 mm surrounding the SAI screw on the side of the pelvic osteotomy. 

Due to pelvic anatomy and previous implants, SAI fixation in patients who have undergone pelvic osteotomy presents technical challenges. Therefore, a shorter SAI screw is typically required on the osteotomy side. However, there were no major issues at the 2-year follow-up for this group of patients, therefore the results were satisfactory.

Source: journals.lww.com/jspinaldisorders/Abstract/2022/11000/Sacral_Alar_Iliac__SAI__Fixation_in_Patients_With.12.aspx