Two-year results for scoliosis secondary to Duchenne muscular dystrophy fused to lumbar 5 with segmental pedicle screw instrumentation.

Background: Instrumentation and fusion to the sacrum/pelvis has been a mainstay in the surgical treatment of scoliosis in patients with Duchenne muscular dystrophy since the development of the intrailiac post. It is recommended for correcting pelvic obliquity. However, caudal extent of instrumentation and fusion has remained a matter of considerable debate. This study was performed to determine the efficacy and safety of stopping segmental pedicle screw constructs at L5 during surgical treatment of scoliosis associated with Duchenne muscular dystrophy (DMD).

Methods: From May 2005 to June 2007, a total of 20 consecutive patients underwent posterior spinal fusion and segmental pedicle screw instrumentation only to L5 for scoliosis secondary to DMD. All patients had progressive scoliosis, difficulty sitting, and back pain before surgery. A minimum 2-year follow-up was required for inclusion in this study. Assessment was performed clinically and with radiological measurements. The Cobb angles of the curves and spinal pelvic obliquity were measured on the coronal plane. Thoracic kyphosis and lumbar lordosis were measured on the sagittal plane. These radiographic assessments were performed before surgery, immediately after surgery, and at a 3-month interval thereafter. The operating time, blood loss, and complications were evaluated. Patients were questioned about whether they had difficulty sitting and felt back pain before surgery and at 6 weeks, 1 year, and 2 years after surgery.

Results: A total of 20 patients, aged 11-17 years, were enrolled. The average follow-up period was 37 months. Preoperative coronal curves averaged 70 degrees (range 51 degrees -85 degrees ), with a postoperative mean of 15 degrees (range 8 degrees -25 degrees ) and a mean of 17 degrees (range 9 degrees -27 degrees ) at the last follow-up. Pelvic obliquity improved from 13 degrees (range 7 degrees -15 degrees ) preoperatively to 5 degrees degrees (range 3 degrees -8 degrees ) postoperatively and 6 degrees (range 3 degrees -9 degrees ) at the last follow-up. Good sagittal plane alignment was recreated and maintained. Only a small loss of correction of scoliosis and pelvic obliquity was noted. The mean operating time was 271 min (range 232-308 min). The mean intraoperative blood loss was 890 ml (range 660-1260 ml). The mean total blood loss was 2100 ml (range 1250-2880 ml). There was no major complication. All patients reported that difficulty sitting and back pain were alleviated after surgery.

Conclusion: Segmental pedicle screw instrumentation and fusion only to L5 is safe and effective in patients with DMD scoliosis of <85 degrees and pelvic obliquity of <15 degrees . Good sagittal plane alignment was achieved and maintained. All patients benefited from surgery in terms of improved quality of life. There was no major complication.