Preoperative Halo Traction with Posterior Spinal Release and Pedicle Screw Fixation for the Treatment of OI with Severe Scoliosis

Abstract

We report the perioperative management, technical pearls and the early surgical outcome of 4 patients with osteogenesis imperfecta (OI) who have undergone surgical correction for their scoliosis. Materials and Methods This is a case series of 6 OI patients, type III (1), IV (3) and V(2) and classified according to clinical classification. The average age was 15.2 years old (12-18). Their pre-operative and post-operative whole spine xrays were evaluated to determine the deformities (level, Cobb’s angle, listing, truncal balance). The patients’ records were also reviewed. The pins for the halo were inserted under local anaesthesia with the position confirmed by CT scan. Traction started from 3Kg and gradually increased weekly by 0.5-1kg. Weekly xrays monitoring to assess for the change in Cobb’s angle and cervical instability. Intraoperatively, tranexamic acid and cell savers were used and patients were monitored by spinal cord monitoring to ensure the safety of the surgery. Posterior releases were done to allow better deformity correction. Pedicle screw fixation system was used in all patients. Results Five patients had undergone a period of pre-operative halotraction. Among them, one had poor tolerance and the traction was stopped prematurely after 17 days with traction reaching about 40% of body weight. One had poor response despite after two months of traction with the weight reaching 42% of body weight. Long spinal fusions were used to correct the deformity.. The average correction of the major curves was from 99.3 degrees (140-72) to 54.4 degrees (71-47). All patients were given spinal braces post-operatively. All were fit for discharge from the hospital within 10 days after surgeries except one due to spinal cord complication (Brown-Séquard syndrome) which subsequently recovered. 3 patients require exchange of pins during traction due to loosening. The others had no major early complication. Union was difficult to assess but no implant loosening was detected in patients being followed up at 1 year post-op in 5 patients. The remaining patient is currently still at early post-op within 1 month.Discussion Scoliosis is common in patients with OI[1]. However, information on the surgical management of scoliosis in patients with OI including the perioperative management is very limited [2,3]. With proper medical treatment, peri-operative care, surgical skills, and stable implant fixation, scoliosis surgery for OI patients should become safer with greater chance of success [4]. The response of the traction varies in our series. Two patients, despite prolonged traction for more than 2 months, the change in scoliosis is only limited. The weight of traction was between 20-45.5%. Beyond that, patients complained of neck and back pain. Even though we could not properly assess the screw fixation stability, patients with pre-op bisphosphonate seemed to have better purchase during screw insertion. Screw fixation was technically demanding especially the rib deformity might affect the screw entry sites. Conclusion Scoliosis surgery is technically demanding. Pre-operative preparation may help to reduce the risk and improve surgical outcome. However, due to the deformity in the spine and ribs, the correction may be limited. Further studies are required to determine the role of pre-op traction to ensure the safety of the surgical treatment.