[Modified primary stable ventral derotation spondylodesis with Halm-Zielke instrumentation for the treatment of idiopathic scoliosis].

OBJECTIVE

Surgical technique with an anterior double-rod system for thoracic, thoracolumbar, or lumbar scoliosis. The aim of the system is to correct the coronal plane deformity and normalize the sagittal balance.

INDICATIONS

Scoliosis which should have a coronal Cobb measurement of at least 40 degrees and should usually not exceed 90 degrees in between T4 and L4. In the Lenke classification, the curve types 1 (main thoracic) and curve type 5 (thoracolumbar/lumbar) are amenable to anterior instrumentation and fusion.

CONTRAINDICATIONS

Osteoporosis. Infection. Allergic reaction to implants. Minor curves that do not correct to < 25 degrees on flexibility maneuvers. Structured kyphosis in the major curve. Severe sagittal plane malalignment with pathologic kyphosis cranial or caudal of the instrumented segments.

SURGICAL TECHNIQUE

The spine is exposed via an open thoracotomy or a thoracoabdominal approach. After completion of diskectomies at each level, the anterior double-rod system is fixed with two bicortical screws per vertebral body. The longitudinal components consist of a solid rod and a threaded rod. The rods are contoured to maintain normal sagittal and coronal contour. The proximal screws are engaged first and then a cantilever force is used to correct the deformity. Occasionally, a partial rod rotation maneuver or intersegmental compression is performed. Morselized autograft (typically rib) is placed in the disk spaces. Intraoperative radiographs are taken to evaluate the correction.

POSTOPERATIVE MANAGEMENT

Brace-free mobilization. Physiotherapy. Respiratory therapy.

RESULTS

Very high rate of successful spondylodesis. Excellent frontal correction of about 60-70%. Very good spontaneous correction of adjacent minor curves of around 40%. Restoration of a physiological profile. Correction angle and length of fusion comparable to modern transpedicular double-rod systems.