Re-assessment system and staged surgical strategy with minimally invasive techniques for treatment of severe adult spinal deformities.

OBJECTIVE: To determine the feasibility of minimally invasive surgery (MIS) for severe adult spinal deformities and propose a re-assessment system and minimally invasive staged surgical strategy.

METHODS: We operated on 53 patients from June 2016 to August 2017 using a re-assessment system and a staged surgical strategy with minimally invasive techniques in minimally invasive spinal deformity surgery (MISDEF) class III; patients with scoliotic apex vertebrae above L1-2 or spontaneous fusion of the facet joints were excluded. The re-assessment system was applied. Stage I involved multi-segment lateral lumbar interbody fusion (LLIF) and anterior column realignment (ACR) and stage II involved posterior minimally invasive surgical treatment. Pre- and post-operative visual analogue scale (VAS), Oswestry disability index (ODI), surgical data, and radiographic images were collected. The major and minor complications were recorded.

RESULTS: All patients were followed for 11.5 months (range, 6-20 months). LLIFs were performed in 168 segments, of which 113 had ACR. The average sagittal correction angle of each ACR segment was 15.6° ± 6.3° (range, 7-28°). The correction rate of the Cobb angle for lumbar scoliosis after stage I was 55.4% and the total correction rate was 75.6%. LL-PI mismatch was improved from -32.8° ± 14.9° to -2.5° ± 9.4°, reaching the sagittal matching state of the lumbar spine.

CONCLUSIONS: A re-assessment system and minimally invasive staged surgery for severe adult spinal deformity can achieve good clinical outcomes and deformity correction and may have the advantage of decreasing unnecessary iatrogenic injury.