Associated lumbar scoliosis does not affect outcomes in patients undergoing focal minimally invasive surgery-transforaminal lumbar interbody fusion (MISTLIF) for neurogenic symptoms-a minimum 2-year follow-up study.

BACKGROUND CONTEXT: There is no current literature comparing outcomes of patients with and without lumbar scoliosis having neurologic symptoms undergoing minimally invasive surgery-transforaminal lumbar interbody fusion (MISTLIF) technique.

PURPOSE: This study aimed to determine whether associated lumbar scoliosis will result in different clinical, radiological, and operative outcomes in patients undergoing focal MISTLIF for neurogenic symptoms, without specific correction of the scoliosis.

STUDY DESIGN: A retrospective case comparison study from prospectively collected hospital registry data was carried out.

PATIENT SAMPLE: Two hundred and thirty eligible patients were evaluated and divided into two groups: Scoliosis Group (SG; n=57) with Cobb angle >10 degrees on anterioposterior (AP) plain lumbar spine radiographs and Non-Scoliosis Group (NSG; n=173) consisting of the remaining patients.

OUTCOME MEASURES: Clinical outcomes were assessed using the Oswestry Disability Index, the North American Spine Society (NASS) Neurogenic Symptom Score, the NASS Satisfaction with Surgery Rating, the 36-Item Short-Form Health Survey (SF-36), and the Numerical Pain Rating Scale for back and leg pain. Radiological findings included Cobb angle, fusion, implant failure or loosening, and adjacent segment degeneration (ASD).

METHODS: Both groups were compared for demographics, perioperative parameters, complications, clinical, and radiological outcomes. Interobserver agreement (kappa statistics) for measurement of Cobb angle was calculated on all cases of both groups by two authors. Patients were evaluated preoperatively, at 6 months, and 2 years after surgery.

RESULTS: The average follow-up was 2.88±1.47 years in the SG and 2.71±1.34 years in the NSG (p=.444). Differences in mean age (SG: 62.9±10.9 years and NSG: 57.6±13.1 years), estimated related risk of death (SG: 3.05±2.13 and NSG: 2.41±1.74), and gender (female=SG: 87.7% and NSG: 64.2%) were statistically significant (p<.05), whereas race distribution, body mass index |(BMI), spinal levels operated, number of levels operated, bone morphogenetic protein (BMP)-2 use, and type of bone graft were not. Fluoroscopic time, operative time, blood loss, postoperative opioid usage, time to ambulation, and length of hospitalization were similar (p>.05). Preoperative and postoperative clinical outcomes were similar in both groups (p>.05) except SF-36 physical function score, which was found to be significantly higher in the NSG at final follow-up (p<.05). Clinical outcomes scores improved significantly postoperatively (p<.05), and grade 1 fusion (Bridwell classification) was achieved in 93% in the SG and in 93.6% in the NSG (p=.417). Total complications were 11 (19.29%) in the SG and 21 (12.13%) in the NSG (p=.097). De novo ASD was found in 1 case in the SG and in 14 cases in the NSG (p=.124), with 1 case in the NSG requiring further surgery.

CONCLUSION: Associated mild lumbar scoliosis (Cobb angle <30°) does not result in significantly different perioperative, clinical, and radiological outcomes in patients undergoing focal decompression and MISTLIF for neurogenic symptoms.