Background:In patients with Scheuermann kyphosis (SK) undergoing posterior spinal fusion with instrumentation (PSFI), intraoperative lateral radiographs assess deformity correction in the prone position. The relationship between thoracic and (partially un-instrumented) lumbar parameters on prone intraoperative versus standing postoperative radiographs is unknown.Methods:Forty-five consecutive patients with SK who underwent PSFI between 2007 and 2014 were reviewed. Thoracic kyphosis (TK), lumbar lordosis (LL), instrumented level kyphosis [upper instrumented vertebrae (UIV)-lower instrumented vertebrae (LIV)], and traditional sagittal parameters were recorded from preoperative standing, intraoperative prone, first outpatient standing, and >2-year standing radiographs and time periods were compared. Exclusion criteria included reduction modification after intraoperative radiographs and postoperative construct revision prohibiting comparison to initial intraoperative radiographs.Results:Twenty-five patients averaging 16 (12 to 20) years old during surgery with 3.1 (2 to 7) years follow-up met inclusion criteria. Average surgical variables included: 13±1 fusion levels, UIV at T2, LIV at L3, 3.8±1.6 osteotomies per patient, and 43±9% correction of TK. Preoperative TK and LL measured 82 and 76 degrees, respectively. TK on intraoperative (47 degrees), 6-week (49 degrees), and >2-year (50 degrees) radiographs changed significantly only between intraoperative and >2-year radiographs (P=0.03) by just 3 degrees. LL increased 5 degrees from intraoperative prone to 6-week standing radiographs (51 to 56 degrees, P=0.01) without further significant change at >2 years (59 degrees, P=0.09). Instrumented levels (UIV-LIV) had increased kyphosis at 6 weeks (32 to 35 degrees, P=0.01) without further change at >2 years (36 degrees, P=0.06).Conclusions:TK on intraoperative prone radiographs during PSFI for SK should match the standing TK ∼6 weeks later. Intraoperative prone LL only slightly increases on early standing radiographs. Assuming a routine postoperative course, intraoperative radiographs slightly underestimate TK (by 3 degrees) and LL (by 8 degrees) on >2-year standing radiographs. These parameters (TK, LL, UIV-LIV) are visualized during surgery and should be used in future studies to predict long-term outcomes.Level of Evidence:Level IV - retrospective study.
- intraoperative radiographs
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health
- Orthopedics and Sports Medicine