#442 Radiographic Correction and Clinical Outcomes of Lateral Lumbar Interbody Fusion (LLIF) with Open versus Percutaneous Screw Fixation in Degenerative Scoliosis Patients

General Session: Lateral Interbody Fusion

Presented by: C. Chang

Author(s):

C. Chang (1)
J. Attenello (1)
Y.P. Lee (1)
S.R. Garfin (1)
R.T. Allen (1)

(1) UC San Diego Health System, Department of Orthopaedic Surgery, La Jolla, CA, USA

Abstract

Object: A retrospective study comparing clinical outcomes and correction of coronal deformity and sagittal alignment in degenerative scoliosis patients, treated with lateral lumbar interbody fusion (LLIF) combined either with percutaneous versus open pedicle screw instrumentation.

Methods: The authors retrospectively reviewed adult deformity cases undergoing combined LLIF and posterior instrumentation at the University of California San Diego Medical Center between August 2009 and September 2011. Patients were divided into two groups: eleven patients underwent LLIF+open posterior pedicle screw instrumentation (Group-1); five patients underwent LLIF+percutaneous pedicle screw instrumentation (Group-2). Data on peri-operative complications were collected. Pre- and post-operative posterior-anterior, lateral scoliosis radiographs, and CT/MRIs were reviewed. Coronal deformity and regional lumbar lordosis were compared between groups. Clinical outcomes evaluation compared pre- and post-operative visual analog scale (VAS) scores, SF-12 scores, and the Oswestry Disability Index (ODI).

Results: In Group-1 (open) all patients had laminectomies and six cases were revisions. Mean pre-operative coronal Cobb in Group-1 was 24.4° (range 11-38°), which corrected to 10.7° post-operatively. For Group-2 pre-operative coronal Cobb was 23.3° (range 14.2-30.4°), improving to 16.7° following surgery. Mean regional lumbar lordosis for Group-1 improved from 30° pre-operatively to 42.3° after surgery, while in Group-2 regional lordosis improved slightly from 26.8° to 29.6° post-operatively. Peri-operative complications occurred only in Group-1, including two wound infections (18%) and one dural tear (9%).

Mean VAS follow-up time was 6 months (range 2-22 months) for Group-1 and 8.3 months (2-22) for Group-2. Mean VAS decreased from 5.1 to 2.5 in Group-1, and from 7 to 1.3 in Group-2. Mean ODI follow-up time for Group-1 and Group-2 were 7.9 months (range 2-17 months) and 17.3 months, respectively. Mean ODI decreased from 45.9% to 20.9% in Group-1, and from 45.7% to 22.8% in Group-2. Mean SF-12 follow-up time for Group-1 and Group-2 were 8.6 months (range 2-17 months) and 25.7 months (24-29), respectively. Mean SF-12 PCS score increased from 27.7 to 39.6 (43% increase) in Group-1, and from 31.7 to 45.6 (44%) in Group-2. Mean SF-12 MCS score increased from 43.8 to 58 in Group-1, and from 54.2 to 57.9 in Group-2.

Conclusions: Radiographically, though coronal Cobb angle and sagittal alignment improved in both groups, they improved significantly more in Group-1. In the percutaneous group, regional lumbar lordosis did not significantly increase, and coronal correction was 28% versus 56% correction in the open group. Significant improvements in VAS, SF-12 PCS, and ODI scores occurred in both groups, but significantly greater improvements in VAS (less pain) were found in Group-2 at latest follow-up. In Group-2, there were no posterior or peri-operative complications. In summary, while open posterior procedures improved radiographic parameters more effectively, it comes at the cost of higher complication rates. The morbidity in adult scoliosis surgery is minimized with less-invasive techniques in carefully selected patients, with similar outcomes compared to the open approach. Percutaneous posterior fixation, without decompression, should be considered part of the algorithm in selected patients with degenerative scoliosis, understanding that differences in patient pathologies, global sagittal/coronal balance, and curve characteristics may necessitate an open approach and higher complication risks.