514 - Temporary Alar Distraction Rods and Sacral Dome Osteotomy in Correctin...

#514 Temporary Alar Distraction Rods and Sacral Dome Osteotomy in Correcting High Grade Spondylolisthesis: Technique, Complications, and Outcomes

Oral Posters: Deformity

Presented by: J. Patterson


J. Patterson (1)
D. Crandall (1), (2), (3)

(1) Banner Samaritan Orthopaedic Residency Program, Phoenix, AZ, USA
(2) Sonoran Spine Center, Mesa, AZ, USA
(3) Sonoran Spine Research and Education Foundation, Phoenix, AZ, USA


Purpose: High grade spondylolisthesis (HGS) 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 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 HGS.

Methods: Prospective data from 26 consecutive patients who underwent surgical treatment of high grade spondylolisthesis were reviewed retrospectively. Age of patients averaged 31years (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). 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, Grade 4- 3, Grade 5- 10. Follow up: 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 HGS. 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.

Figure 1 Sacral osteotomy

Temporary alar distraction rods prior to construct