495 - Lumbar Alignment after Long Fusion Surgery with Hip Extension Position...

#495 Lumbar Alignment after Long Fusion Surgery with Hip Extension Position on the Orthopaedic Systems Inc.(OSI) “Jackson Frame” without Correction Osteotomy

Sagittal Balance

Poster Presented by: T. Iizuka

Author(s):

T. Iizuka (1)
Y. Ueda (1)
M. Ikenaga (1)
K. Naito (1)
M. Yamada (1)
Y. Tagawa (1)

(1) Nishinokyo Hospital, Orthopaedic Surgery, Nara, Japan

Abstract

Study Design: A retrospective evaluation.

Objective: To evaluate lumbar sagittal alignment in spinal deformity patients who underwent an instrumented posterior spinal fusion with hip extension position.

Summary of Background Data: Intraoperative prone positioning with conventional hip flexion causes loss of lumbar lordosis in adults' lumbar fixation surgery. However no precise data is available concerning lumbar alignment after surgery. Spinal sagittal alignment may often depend on the patients' position at the operating table. Hip extension position may increase and preserve ideal lumbar lordosis because this position provides similar standing lumbar spinal alignment rather than hip flexion position. The results of lumbar alignment with hip extension position on the Orthopedic Systems Inc. (OSI) "Jackson" frame have not been reported precisely before.

Methods: Radiographs of 126 operative spinal deformity patients (70females/56males; mean age, 71.8 years) were analyzed (Jan.2011-Dec.2012). Diagnoses included degenerative lumbar scoliosis (6), lumbar canal stenosis (117) and others (3). Total lumbar lordosis (L1-S1) was measured on preoperative upright and supine position, and postoperative upright lateral radiographs. All patients underwent decompression and spinal fusions using posterior instrumentations with hip extension on Jackson frame. Spinal fusions were performed at 1 level (Group1) in 13 patients, 2 (Group 2) in 36 , 3 (Group 3) in 45, 4 (Group 4) in 24 and more than 5 levels (Group 5) in 8 patients. The change of sagittal alignment was evaluated by δ= (postoperative L1-S1 angle) - (preoperative L1-S1 angle).

Results: Average preoperative upright and supine and postoperative upright lumbar lordosis (L1-S1) measurements were 34.3 degrees and 34.0 (N.S.) respectively (δ=0.3). The change of lumbar lordosis (δ) was 4.00 in Group 1, 1.56 in Group 2, -0.96 in Group 3, -3.67 in Group 4 and -0.50 in Group5. The values of δ in Group 3 and 4 were significantly lower than Group 1 (P< 0.05). 

Conclusion: In adult lumbar fusion surgery, the prone position with hip extension posture on Jackson frame preserved the preoperative lumbar sagittal alignment in this study. The alignment of Group 1 was decreased 4.0 degrees even with hip extension position. The lumbar lordosis was increased in Group 3 (-0.96) and Group 4 (-3.67). Vertebral osteotomy or pedicle subtraction osteotomy should be considered if correction is required in short segments. This result may help to make a scheme for reconstructive surgery with adult lumbar deformity concerning the lumbar sagittal alignment.