Scheuermanns kyphosis correction through the pivoting reduction post on the new multiplanar adjusting screw technique and 2 year results

2005

BACKGROUND CONTEXT

Scheuermann´s kyphosis is usually corrected with a combined anterior and posterior approach, with posterior column shortening and posterior osteotomies. Cantilever correction has also been described. A new technique for achieving highly controlled kyphosis correction was developed using the 160° pivoting reduction post on the new Multi-Planar Adjusting (MPA) screw to pull the spine to the rods.

PURPOSE

This study was undertaken to determine whether a slow and highly controlled cantilever force applied through the pivoting reduction posts on the MPA screws would achieve safe and reliable correction in Scheuermann´s kyphosis patients without posterior osteotomies.

STUDY DESIGN/ SETTING

A prospective analysis of Scheuermann´s kyphosis patients treated with anterior thoracoscopic release and posterior instrumented correction using the new technique. Patients were followed 31 mo (2–4 yrs).

PATIENT SAMPLE

Seven consecutive patients averaged 86° kyphosis (73–91°) underwent posterior instrumented correction by direct vertebral translation using MPA screws. Six were male and one female. Average age was 23 yrs (14–62 yrs).

OUTCOME MEASURES

Oswestry and Visual Analog pain Scores (VAS), pain medication records, and work status were followed. Radiographs were obtained at 6 wks, 3, 6, 9, 12, 24 mo, and yearly thereafter.

METHODS

Indications for surgery included kyphosis progression, failure of bracing, and pain not responding to conservative care. All patients had anterior thoracoscopic release and cancellous allograft arthrodesis prior to the same day posterior corrective surgery. Posterior hook or screw fixation was used above the kyphosis apex and MPA screws below. Rods were contoured to fit the normal upper thoracic spine above the gibbus, and left uncontoured distally. The pivoting reduction posts on the MPA screws were attached to the distal uncontoured portion of the rods, with the rods being left four to six inches above the spine. From this starting point, the spine was gradually brought up to the rods by applying a direct anteroposterior force to pull the vertebra into the proper position. This was achieved by repeated incremental tightening of the reduction nuts on the MPA screw posts. As the kyphosis was reduced, the posterior column was compressed. The reduction process averaged 60 minutes. Though posterior facets were debrided, posterior osteotomies were not performed.

RESULTS

Complications included junctional kyphosis at T1-2 requiring revision in a patient with Ehlers Danlos syndrome. There were no neurologic deficits, nonunions or infections. None of the MPA screws pulled out during the reduction process. The kyphosis which averaged 86 degrees (73–91°) corrected to 37 degrees (23–49°). Clinically, all patients with pre-op pain noted a decrease in VAS pain scores (4.6 pre-op to 1.5 post-op) and medication requirements by latest follow-up. Oswestry scores showed similar improvement (21 pre-op to 9 post-op). All 6 patients that were students or working pre-op returned to school or work, and the one patient who was retired pre-op resumed active retirement.

CONCLUSION

Kyphosis correction by gradually translating the spine into the desired position was safely achieved using the reduction post on the MPA screws, without posterior osteotomies. Two year results with this technique showed the correction was maintained, and functional status improved in these patients.