Study Design. Retrospective matched-cohort analysis.
Objective. To evaluate the change in radiographical parameters in patients undergoing interbody fusion and posterior instrumentation compared with posterior spine fusion (PSF) alone for degenerative scoliosis.
Summary of Background Data. Little is known about the effect of lateral interbody fusion (LIF) on sagittal plane correction in the setting of degenerative scoliosis. We performed a retrospective study to investigate these changes compared with PSF.
Methods. Between 1997 and 2011, 33 patients had LIF at 181 levels between T8 and L5 vertebrae for the treatment of degenerative scoliosis (mean; 5 ± 2 levels). Of those, 23 patients had additional anterior lumbar interbody fusion (ALIF) at 37 levels between L4 and S1 vertebrae (mean; 1.6 ± 0.5 levels). A 1:1 matched control of patients who underwent PSF was performed. Patients were matched by age, sex, and diagnosis. Clinical and radiographical data were collected and compared between the matched cohorts.
Results. Lumbar lordosis (LL) was significantly restored in the LIF ± ALIF compared with PSF cohort (44° ± 14° vs. 36° ± 15°, P = 0.02). The segmental LL over the 102 LIF levels significantly improved from 12°± 10° to 21°± 13° postoperatively (P < 0.0001). However, the change over the 37 ALIF levels was not significant (from 30° ± 15° to 29° ± 9°, P = 0.8). Sagittal plane alignment was improved in the LIF ± ALIF compared with PSF cohort and trended toward but did not reach significance (3.8 ± 3.2 cm vs. 6.2 ± 5.7 cm, P = 0.09). Sacral slope was significantly higher in the LIF ± ALIF compared with PSF cohort (33° ± 11° vs. 28° ± 10°, P = 0.03). Pelvic tilt was lower in the LIF ± ALIF compared with PSF cohort and trended toward but did not reach significance (22° ± 10° vs. 26° ± 10°, P = 0.08).
Conclusion. LL and sacral slope had mildly but statistically improved in the interbody fusion cohort compared with PSF cohort. Sagittal alignment and pelvic tilt trended toward but did not reach statistical significance. Segmental LL was improved at LIF levels more than at ALIF levels.
Level of Evidence: 3
A matched-cohort analysis of radiographical parameters was conducted between patients undergoing interbody fusion with posterior instrumentation versus posterior fusion alone for degenerative scoliosis. Lumbar lordosis and sacral slope had significantly improved in the interbody cohort. Sagittal alignment and pelvic tilt trended toward favoring the interbody cohort.
*Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN
†Center of Orthopedic Research and Education (CORE) Institute, Sun City West, AZ
‡Department of Orthopedic Surgery, Guang An Men Hospital, Beijing, China; and
§Department of Orthopedic Surgery, University of Hawaii, Honolulu, Hawaii.
Address correspondence and reprint requests to Ahmad Nassr, MD, Mayo Clinic, Department of Orthopedic Surgery, 200 First St SW, Rochester, MN 55905, E-mail: firstname.lastname@example.org
Acknowledgment date: May 22, 2013. First revision date: August 29, 2013. Acceptance date: October 2, 2013.
The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.
CTSA Grant Number UL1 TR000135 from the National Center for Advancing Translational Sciences (NCATS), a component of the National Institutes of Health (NIH), funds were received to support this work. The contents of this work are solely the responsibility of the authors and do not necessarily represent the official view of NIH.
Relevant financial activities outside the submitted work: grant, board membership, patents, royalties, grants/grants pending, and fees for participation in review activities.