S2 Alar-iliac Fixation: A Powerful Procedure for the Treatment of Kyphoscoliosis

The purpose of this study was to introduce a powerful technique for the treatment of kyphoscoliosis. There are currently multiple techniques for sacropelvic fixation, including trans-iliac bars and iliac and iliosacral screws. Several studies have documented the use of these instrumentation techniques; however, a ubiquitous problematic issue concerns the need for separate incisions for the use of offset connectors, which add to surgical time and morbidity. Any additional dissection of the skin, subcutaneous tissue or muscle in this area is believed to increase the incidence of complications of wound healing. However, as stated above, the above-mentioned techniques require separate incisions for the use of offset connectors, which add to surgical time and morbidity. The novel technique of S2 alar-iliac (S2AI) pelvic fixation has been developed to address some of these issues. However, a technique for achieving correction of kyphoscoliosis with pelvic obliquity in adult patients with spinal deformity has not previously been described. Our entry point is based on the S1 foramen and is typically up to 5 mm caudal and 2 to 3 mm lateral to that foramen. Once the S1 foramen has been identified, a blunt instrument can be used to probe the alar ridge. The screw trajectory is 40°-50° from horizontal and 20°-30° caudal, aimed toward the greater trochanter and rostral to the sciatic notch. A 36-year-old female patient presented with a 3-year history of low back pain, and progressive thoracolumbar kyphoscoliosis. In this typical case, we performed S2AI fixation with transforaminal lumbar interbody fusion and hemivertebra resection technique to treat her lumbosacral kyphoscoliosis. Satisfactory improvement in her preoperative lumbar kyphoscoliosis was found at 3-month follow-up.