Purpose: To evaluate the effect of interbody distraction by OLIF for the treatment of adult spinal deformity.
Overview of Literature: Adult spinal deformity with symptomatic stenosis has been addressed conventionally using a direct posterior decompression approach with fusion. However, stenotic symptoms can also be alleviated indirectly through restoration of intervertebral and foraminal heights and correction of spinal alignment.
Methods: Twenty-eight patients with adult spinal deformity underwent OLIF combined with modified cortical bone trajectory screws at 94 lumbar levels with neuromonitoring. The patients were divided into three groups based on their preoperative lumbar lordosis: group A, <0°; group B, 0°-20°; and group C, >20°. The cross-sectional area (CSA) of the thecal sac was measured preoperatively and postoperatively on axial magnetic resonance images. Differences in CSA were evaluated, and the relationship between the CSA extension ratio and preoperative CSA was assessed. Changes in disc height and segmental disc angle were measured from plain radiographs.
Results: OLIFs were performed successfully without neural complications. In group A, the mean CSA increased from 120.6 mm2 preoperatively to 148.5 mm2 postoperatively (p <0.001). The mean CSA for group B increased from 120.1 mm2 preoperatively to 154.4 mm2 postoperatively (p <0.001). Group C had an increase in mean CSA from 114.7 mm2 preoperatively to 160.7 mm2 postoperatively (p <0.001). The mean CSA enlargement ratio was 27.5%, 32.1%, and 60.4% in groups A, B, and C, respectively. The mean CSA extension ratio was inversely correlated with preoperative CSA.
Conclusions: The effect of indirect neural decompression in adult spinal deformity with OLIF varies with the degree of preoperative lumbar lordosis.
MATERIALS AND METHODS: This is an observational cross-sectional study conducted on all degenerative spine disease patients who underwent both methods of posterior lumbar instrumentation and fusion from 2010 to 2014 by the Orthopedic and Neurosurgery Department, Sarawak General Hospital. The analyzed variables were method of surgery and the levels involved, demographic data, estimated blood loss, duration of operation, length of hospitalization, visual analog scale of back pain and radicular pain preoperative, postoperative 1 month, 3 months, 6 months, 1 year, and functional outcome.
RESULTS: One hundred and twenty-two patients underwent posterior lumbar instrumentation and fusion from 2010 to 2014. Seventy patients were subjected to MIS transforaminal lumbar interbody fusion (TLIF) and 52 open TLIF. Total 89 patients underwent single level of lumbar fusion with sixty patients in MIS group and 29 in open surgeries. MIS TLIF has less estimated blood loss and shorter hospitalization and longer operation time compared to open TLIF, which were statistically significance. MIS TLIF has statistically significance better functional outcome based on Oswestry disability index, Modified NASS score, and RAND 36-item Health Survey 1.0 score. Complications such as infection, new onsets of neurological, and dural tear are equal in both methods of surgery.
CONCLUSION: This study concluded that MIS has better functional outcome compared to open TLIF with shorter hospitalization, faster return to work, and less estimated blood loss.