MANAGEMENT OF FIXED SAGITTAL DEFORMITY OF THE SPINE: CLINICAL RESULTS OF TRANSPEDICULAR WEDGE RESECTION (THOMASEN)

Sigurd Berven, MD;
Vedat Deviren, MD;
Arash Emami, MD;
Jason Smith, MD;
Serena Hu, MD;
David S. Bradford, MD
San Francisco, CA, USA

INTRODUCTION:
Since Thomasen's description of the transpedicular wedge resection in 1985, there has been little data in the Orthopaedic literature describing results of the procedure in patients with lumbar kyphosis due to etiologies other than ankylosing spondylitis. The purpose of this paper is to report the efficacy and clinical value of the Thomsen transpedicular wedge resection for the treatment of fixed sagittal plane deformity.

METHODS:
Thirteen consecutive patients (8 female, 5 male), average age 46 years, underwent a transpedicular wedge resection at L2, L3, L4, or L5 for correction of a fixed sagittal plane deformity. Etiology of the deformity was malalignment of prior lumbar fusion (7), ankylosing spondylitis (4), congenital hemivertebra (1), and infection (1). Outcome parameters included modified SRS scores, radiographic measures, and complications.

RESULTS:
Clinical follow–up averaged 57 mos (range 24–103). All patients were extremely (54%) or somewhat (46%) satisfied with their surgery. 10/13 (77%) would definitely repeat their surgery, 2/13 (15%) would probably repeat surgery, and 1/13 (8%) is unsure. Radiographic outcomes demonstrate an improvement of sagittal alignment (C7 to sacral promentory) from 14.8cm (6–24) to 4.6cm (0–14), 70% correction. Lumbar lordosis increased from 21 (–6–40) degrees to 47 (26–65) degrees. Coronal plane deformity (C7 to CSL) improved 50%, from 2.2cm (range 0–5.5) to 1.1cm (0–2.1). Complications occurred in 7 patients and included dural tear (4), transient paresis (4), pulmonary embolus (1). The preoperative diagnosis did not determine clinical outcome. There was no correlation between radiographic improvement and clinical outcome.

DISCUSSION:
The transpedicular wedge resection is an effective technique for the correction of fixed sagittal plane deformity due to loss of lumbar lordosis, with apex of deformity below L1, and a magnitude of deformity correctable with a single–level closing wedge. A pre–existing circumferential fusion in sagittal malalignment is optimally addressed with this technique and a maximum 40 degree correction of kyphosis was possible. Although this has not previously been described, coronal plane decompensation was well corrected with this procedure in patients with fixed imbalance. Other advantages of the transpedicular wedge resection over alternative techniques include single stage correction, posterior column shortening without distraction of the anterior column, and expansion of the space available for neural elements. The technique is equally useful for treatment of ankylosing spondylitis as well as flat–back syndrome. There were no long–term complications observed in this series.