Submuscular Isola Rod With and Without Limited Apical Fusion in the Management of Severe Spinal Deformities in Young Children

Laurel C. Blakemore, MD,
Peter V. Scoles, MD,
Connie Poe–Kochert CPNP,
George H. Thompson, MD
Cleveland, Ohio USA

PURPOSE:
The management of severe progressive spinal deformities in young children is difficult and controversial.

METHODS:
Between 1993 and 1999, we managed 29 such children who had orthotic failure or contraindications to an orthosis. Our protocol consisted of insertion of a submuscular Isola rod, with or without an anterior and posterior apical fusion and a postoperative orthosis. The rod is left 3–4 cm long, usually below the lower hook. The rod is lengthened periodically to accommodate growth and deformity progression. A definitive spinal fusion is performed in early adolesence.

RESULTS:
There were 10 males and 19 females. This included 10 children with idiopathic scoliosis (infantile and juvenile), 6 with neuromuscular disorders. 4 with congenital scoliosis, 6 with syndromes, and one each with a spinal cord injury, spinal cord tumor, and spinal cord infarct. The mean age at surgery was 6.9 years (range, 1 – 11 years). The patients were divided into two groups: Group A included short anterior and posterior apical spinal fusion and submuscular Isola rod and Group B submuscular Isola rod without fusion. There were 11 patients in Group A and 18 in Group B. Preoperative, initial postoperative, and most recent follow–up radiographs were analyzed. The mean postoperative follow–up was 31 months (range, 2–63 months). The mean number of rod lengthenings was 2 (range, 0–5). The mean preoperative curve was 66º (range, 40–112º). The initial mean postoperative curve was 37º (range, 16–54º). The most recent radiographs showed a mean curve of 45º (range, 28–69º). Curve correction was maximal following the initial procedure. Preoperative curve magnitude was larger in the Group A (75º) than Group B (61º). The final correction was similar in the two groups. Nine patients in Group B have completed their course of treatment and have undergone spinal fusion at a mean age of 11.2 years (range, 10–13 years). Seven patients (24%) sustained 8 complications: 5 from Group A and 2 in Group B. This included 3 rod breakages and 5 hook displacements, all of which required revision. There was one superficial wound infection treated medically.

CONCLUSIONS:
This submuscular Isola rod protocol has been very effective in the management of severe progressive spinal deformities in young children. Correction in the more severe curves is enhanced by the inclusion of a short apical fusion. The submuscular rod improved spinal alignment and allowed continued spinal growth delaying the need for definitive fusion. The complication rate has been acceptably low. The protocol was well tolerated by the families and patients.