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One Versus Two BAK Fusion Cages in Posterior Lumbar Interbody Fusion to L4L5 Degenerative Spondylolisthesis: A Randomized, Controlled Prospective Study in 25 Patients With Minimum Two-Year Follow-up

Zhao, Jie MD; Wang, Xinwei MD; Hou, Tiesheng MD; He, Shisheng MD

Spine:
Randomized Trial
Abstract

Study Design. We accomplish posterior lumbar interbody fusion using posterolateral insertion of a single BAK fusion cage (Sulzer Spine-Tech, Minneapolis, MN) with unilateral facetectomy and hemilaminectomy.

Objective. To subject a single BAK fusion cage inserted posterolaterally in posterior lumbar interbody fusion to a randomized, controlled trial to assess its clinical safety and efficacy.

Summary of Background Data. Routinely, two threaded cages in posterior lumbar interbody fusion have been recommended, which need bilateral facetectomy, extensive exposure, and retraction of cauda equina. Our biomechanical study showed that it is feasible to accomplish posterior lumbar interbody fusion using posterolateral insertion of a single threaded cage with unilateral facetectomy and hemilaminectomy.

Materials and Methods. Patients with a primary diagnosis of L4–L5 degenerative spondylolisthesis accompanied by low back pain and unilateral leg pain, having failed conservative treatment, were considered for the procedure. Twenty-five patients were randomized into two groups of 13 and 12, respectively, using a random number table. Group 1 had a single BAK fusion cage inserted posterolaterally and oriented counter anterolaterally on the symptomatic side with unilateral facetectomy and hemilaminectomy. Group 2 had two BAK fusion cages inserted posteriorly with bilateral facetectomy and laminectomy.

Results. A total of 12 of 13 patients in Group 1 and 11 of 12 patients in Group 2 achieved successful radiographic arthrodesis. Clinical results at 2 years for 7 of 13 patients in Group 1 were excellent, 4 of 13 were good, 2 of 13 fair, and no poor clinical results; 4 of 12 patients in Group 2 were excellent, 5 of 12 good, 1 of 12 fair, and 2 of 12 poor. Regarding complications, 2 of 12 in Group 2 had a postoperative motor and sensory deficit of the opposite adjacent (upper) nerve root.

Conclusion. Posterior lumbar interbody fusion using diagonal insertion of a single threaded cage by a posterior approach with unilateral facetectomy enables sufficient decompression and solid interbody arthrodesis to be achieved while maintaining a majority of the posterior elements. It is a clinically safe, easy, and economic technique to treat lumbar degenerative spondylolisthesis.

Author Information

From the Orthopedic Surgery Department, Changhai Hospital, Shanghai, People’s Republic of China.

Acknowledgment date: December 12, 2000.

First revision date: November 9, 2001. Second revision date: February 14, 2002.

Acceptance date: March 4, 2002.

The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.

No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Address correspondence to Jie Zhao, MD, Orthopedic Surgery Department, Changhai Hospital, 174 Changhai Road, Shanghai 200433, People’s Republic of China; E-mail: orth.wang@263.net

© 2002 Lippincott Williams & Wilkins, Inc.