P90. To prevent PJK in Scheuermann's Kyphosis, restore kyphosis to patient's PI value and choose proximal UIV

BACKGROUND CONTEXT Incidence of proximal junctional kyphosis (PJK) in Scheuermann's Kyphosis (SK) varies between 24–40%. Multiple factors have been implicated, including: overcorrection of kyphosis, failure to include the proximal end vertebra and choice of implants. Recently, studies have attempted to analyze pelvic parameters in SK, including lumbopelvic mismatch. However, the issue remains unresolved. PURPOSE This study aimed to determine the goal correction parameters based upon patients’ kyphosis, pelvic incidence, and UIV to prevent PJK in Scheuermann's Kyphosis. STUDY DESIGN/SETTING Retrospective Chart Review. PATIENT SAMPLE A total of 96 Sheuermann Kyphosis patients undergoing correction procedures with all pedicle screws (PS), hybrid fixation (HF) or anterior/posterior fusions with hybrid fixation (AP). OUTCOME MEASURES Kyphosis minus pelvic incidence > -10° was determined to be normal. T1/T2 were grouped together as proximal fusion group compared to T3 and distal group. METHODS X-ray and chart review of all SK patients analyzed and compared. RESULTS 96 total patients: PS (n=41), HF (n=24), and AP (n=31). Overall, at early postop 12/96 (12.5%) patients had PJK. At final follow-up 33/96 (34.4%) had PJK. There was no significant difference between groups at early postop (p = 0.86) or final follow-up (p = 0.67). When correcting Kyphosis-PI to > -10° and UIV was chosen to be T1 or T2, PJK developed in 6% of patients. When fusing to T1/T2 and having kyphosis-PI -10° but UIV chosen at T3 or below, 77.8% of patients developed PJK. When fusing to T3 or below and failing to correct kyphosis-PI to > -10°, 37% of patients developed PJK. CONCLUSIONS While surgical techniques and implants do not seem to have a substantial role in development of PJK, selecting proximal UIV and avoiding Kyphosis-PI mismatch can significantly decrease this possibility. Surgeons treating Scheuermann's Kyphosis should, therefore, aim to correct kyphosis closer to patient's pelvic incidence. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.