Pedicle Screw-only Constructs With Lumbar or Pelvic Fixation for Spinal Stabilization in Patients With Duchenne Muscular Dystrophy

Abstract

Study Design: Retrospective case study. Objective: We present a retrospective clinical study of 36 patients of Duchenne muscular dystrophy (DMD) treated for correction of scoliosis with pedicle screw-only constructs with the objective to analyze our technique, correction and maintenance of spinal and pelvic deformity, spinal fusion, the complications we encountered, and the adequacy of lumbar fixation. Summary of Background Data: Pedicle screw constructs have shown better deformity correction and maintenance as compared with other methods of instrumentation in adolescent idiopathic scoliosis. There are very few reports of pedicle screw-only constructs for DMD patients. Methods: Thirty-six patients were followed up for an average period of 37.75 months (min 24 mo). All patients were instrumented from T2, T3, or T4 to L5 and all levels were instrumented. Pelvic fixation was performed only if the pelvic tilt was more than 15 degrees (10 patients). Results: Cobb angle improved 65% (P<0.001) after surgery from a mean preoperative value of 71 degrees to an average postoperative value of 25.5 degrees. Balanced sitting posture was obtained in all patients. The lumbar lordosis improved significantly (P<0.0001) from an average preoperative value of -21.4 degrees to a mean immediate postoperative value of 23.7 degrees and to 19.5 degrees at final follow-up. In patients where pelvic fixation was performed, pelvic tilt improved 62% (P<0.0001) from an average of 25.8 degrees preoperatively to 9 degrees postoperatively to 11 degrees at final follow-up. In patients where pelvic fixation was not performed, the pelvic obliquity also improved from 10.5 degrees preoperatively to 5.8 degrees postoperatively (41.5% correction) and 8.5 degrees at final follow-up (4.2% correction). Conclusions: Pedicle screw-only constructs provide good stability allowing better correction and maintenance of coronal and lumbar deformities, obtaining good sitting balance, and mobilizing patients early after surgery. Longer follow-up is required to adequately comment on the need for pelvic stabilization.