Alternate Pedicle Screws Technique versus Hybrid Construct for the Correction of Adolescent Idiopathic Scoliosis: A Prospect ive Randomized Study

Abstract

Background Data: The use of all pedicle screws technique, instead of hybrid constructs,for the treatment of AIS became more popular over the past several years. Studies to compare both techniques were usually retrospectively performed.Purpose: To compare between an alternate all pedicle screws technique and hybrid constructs in correction of AIS in a prospective trial. Study Design: Prospective, non-randomized. Patients and Methods: The study included 50 patients with adolescent idiopathic scoliosis divided into 2 groups; 27 patients had surgical correction using alternate pedicle screws technique (Group 1) and 23 patients had surgical correction using hybrid constructs (Group 2). The age at surgery had an average of 15y + 7m in Group 1 and 14y + 8m in Group 2. The dorsal curves in Group 1 ranged from 40o to 62o with a mean of 46.5o and in group 2 ranged from 32o to 79o with a mean of 54.3o. The lumbar curves rangedfrom 14o to 73o with a mean of 41.7o in Group 1 and in Group 2 ranged from 31o to 77o with a mean of 46.8o. The deformity was measured by Cobb’s method preoperatively, postoperatively and at final follow up with measurement of postoperative correction %. Operative time and blood loss were also measured and recorded. All patients hadposterior correction, instrumentation and fusion using either an all pedicle screws technique, in an alternating manner, (Group 1); or a hybrid construct including pedicle screws, hooks and sublaminar wires (Group 2).Results: The dorsal curves were corrected in group 1 and group 2 to a mean of 18.2o and 20.9o respectively. The lumbar curves were corrected in group 1 and group 2 to a mean of 14.6o and 17.7o respectively. Patients were followed up for a minimum of 2 years with an average loss of correction of 2.2° and 2.0o respectively. Overall, there was no majorpostoperative neurological deficit and no metal failure in either group. Conclusion: Correctional power of alternating all screws technique for AIS in the coronal plane was slightly but insignificantly better than hybrid constructs. However,the correction of vertebral rotation was significantly better leading to a lesser need for thoracoplasty with its consequent hazards. (2012ESJ010)