Assistance with reduction of high grade spondylolisthesis using temporary alar distraction rods and sacral dome osteotomy in correcting high grade spondylolisthesis: technique, complications, and outcomes

2013

Background

High grade spondylolisthesis can present with significant pain, neurologic deficits and significant deformity. Most advocate decompression along with some amount of instrumented reduction to correct lumbosacral kyphosis and sagittal plane imbalance.

Purpose

Purpose of the study is to describe the use of temporary alar distraction rods and sacral dome osteotomy to assist in the gradual instrumented reduction of high grade spondylolisthesis.

Study Design

Retrospective review of clinical and radiographic data

Patient Sample

26 consecutive patients who underwent surgical treatment of high grade spondylolisthesis were reviewed retrospectively. Age of patients averaged 31 years (range 10 – 50 years; 22 Female, 4 Male). Included: high grade developmental spondylolisthesis (isthmic or dysplastic). Excluded: low grade spondylolisthesis or acquired spondylolisthesis (traumatic, post-operative, pathological, degenerative).

Outcome measure

Visual Analog Pain scores (VAS) and Oswestry Disability Index (ODI) scores, complications

Methods

All patients underwent posterior only approach, Gill laminectomy, slow incremental translational correction of lumbosacral kyphosis and listhesis, and instrumented posterolateral arthrodesis. For grade 4 and 5, sacral dome osteotomy was performed to loosen L5 and allow correction. Temporary contoured rods were placed from L1 and the sacral ala to distract and begin to lift L5 from lumbosacral kyphosis, and begin the reduction process as the laminectomy and construct assembly were completed.

Results

Meyerding grades: Grade 3- 13 patients, Grade 4- 3 patients, Grade 5– 10 patients. Follow up was 2-10 years. For grades 4 and 5, 3-column sacral dome osteotomy rendered L5 more mobile, and temporary alar distraction rods were effective at improving lumbosacral alignment while remaining out of the way during laminectomy and screw insertion. Complications included 2 foot drop, 1 temporary quadriceps weakness (resolved by 12 months) and 3 infections. The 5 patients that presented with cauda equina syndrome improved. Clinical outcomes: VAS averaged 6.2 pre-op, improved to 2.0 at 2 years (p <0.01). Oswestry averaged 35 pre-op improved to 17.2 at 2 years (p <0.01).

Conclusions

A strong flexion moment and kyphosis at the lumbosacral junction along with significant ligament and bony obstacles impede reduction of high grade spondylolisthesis. Translational correction of high grade spondylolisthesis, restoration of lumbosacral alignment and sagittal balance produces significant long-term clinical improvements (ODI and VAS). For grade 4 and 5 listhesis, sacral dome osteotomy and temporary alar distraction rods were helpful in facilitating safe decompression and gradual translational reduction. Neurologic complications occurred in 10%, all with spondyloptosis.