Study Design. A case report of 3 patients with posterior migration of bullet-shaped fusion cages after transforaminal lumbar interbody fusion (TLIF). One patient required emergency revision surgery; the other 2 patients are being observed during conservative treatment.
Objective. To review cases of posterior migration of fusion cages and report ensuing clinical courses.
Summary of Background Data. TLIF is a commonly used procedure; however, there are few reports describing cage migration after the procedure. In most cases, when posterior cage migration follows posterior lumbar interbody fusion, emergency revision surgery is required. One recent study reported a case of posterior cage migration after TLIF, which was treated conservatively.
Methods. Posterior migration of the bullet-shaped fusion cages occurred 1 to 2 months after TLIF in 3 patients. One of the 3 patients had isthmic spondylolisthesis treated by TLIF with bilateral pedicle screw fixation. The other 2 patients had degenerative scoliosis and were treated by TLIF with unilateral pedicle screw fixation.
Results. The patient with isthmic spondylolisthesis required revision surgery because the migrated cage caused nerve root irritation. The migrated cage was removed and a large-sized cage was employed to achieve stability. The other 2 patients had no pathologic symptoms after the posterior migration of the cage and were treated conservatively and observed.
Conclusion. Revision surgery after TLIF appears relatively safe because the migrated cage tends to locate more laterally than in patients with cage migration after posterior lumbar interbody fusion. Cage migration subsequent to TLIF may not cause compression of neural tissues, so conservative treatment may suffice for these patients. Unilateral pedicle screw fixation may not provide sufficient stability to prevent cage migration in patients with degenerative scoliosis. Further study is needed to clarify surgical indications for unilateral pedicle screw fixation in TLIF.
Three patients had posterior migration of bullet-shaped cages after transforaminal lumbar interbody fusion, one of which required emergency revision surgery. The revision surgery was relatively safe because the migrated cage was located more laterally in comparison with the cage migration after posterior lumbar interbody fusion. If the migrated cage causes no damage to neural tissues, the patients may be treated conservatively.
From the *Department of Orthopedic Surgery, Chiba Rosai Hospital, Japan; and †Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Japan.
Acknowledgment date: January 18, 2008. First revision date: April 23, 2008. Acceptance date: July 7, 2008.
The legal regulatory status of the device(s)/drug(s) that is/are the subject of this manuscript is not applicable in my country.
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 for correspondence and reprint requests to Yasuchika Aoki, MD, Department of Orthopedic Surgery, Chiba Rosai Hospital, 2–16 Tatsumidai-higashi, Ichihara, Chiba, 290-0003, Japan; E-mail: yasuaoki@h6.dion.ne.jp
