TREATMENT OF NEUROMUSCULAR SCOLIOSIS USING SUBCUTANEOUS RODS WITHOUT GRAFTING

Abstract

Purpose: The Harrington instrumentation without vertebral grafting associated with corset treatment was described by Joe Moe in 1978 for the treatment of severe scoliosis in young children. In 1989, Jean Dubousset described the ratchet-brace process which occurs after isolated posterior vertebral grafting performed before the end of growth. Thus several options should be discussed for young children with a severe evolving scoliosis inaccessible to orthopaedic treatment: a subcutaneous rod to be lengthened repeatedly without grafting, anterior epiphysiodesis fusion, or a combination of these methods. The purpose of this retrospective analysis was to examine the posterior approach using a subcutaneous rod without grafting.

Material and methods: Fourteen children with scoliosis were treated over a ten-year period: infantile spinal amyotrophy (n=10), cerebral palsy (n=3), congenital (n=1). Mean age at the first operation was 8.6 years. Mean preoperative Cobb angle was 72.5° (45–105°). From the third case onward, the treatment protocol was the same for all patients using proximally three hooks on three thoracic vertebrae mounted on a rod and distally two hooks (L4-L5) mounted on a second rod. The two subcutaneous rods were connected with a connecting device and the fusion grafts were inserted. The first lengthening was planned at about six months. Further lengthenings were planned for about once a year until Risser 2 when spinal fusion could be undertaken.

Results: The first operation corrected the curvature to 43.7° (28–70°) On average, four lengthenings were performed before definitive fusion. Each lengthening (mean 13.7 mm (10–20) produced an average 16.4° (4–31°) correction. Mechanical complications (one proximal hook pull out, one rod fracture) occurred during the learning period (first patient) before the present technique was instituted.

Discussion: The absence of mechanical complications with the described method and the quality of the results suggests this technique should be pursued, avoiding the anterior approach in certain patients where respiratory function is compromised. The inconvenience of the annual operations for lengthening may be avoided with the self-lengthening Phenix #1666 rods.