Triple-Rod Construct Approach for Severe Rigid Scoliosis: A Comprehensive Case Series.

Objective: Scoliosis is a complex three-dimensional deformity of the spine that leads to lateral curvature, rotation, and imbalance. The severity of scoliosis varies, ranging from mild cases requiring observation to severe, rigid deformities that may necessitate surgical intervention. The surgical management of severe rigid scoliosis carries with it several devastating complications, such as neurological injury, bleeding, implant failure, or loss of correction. The triple-rod technique is an advanced spinal instrumentation method for correcting severe and rigid scoliosis, involving the sequential placement of three rods to enhance deformity correction, reduce mechanical stress on the primary rods, and improve the stability of the construct. These are eight patients among many who presented with varying etiologies of severe rigid scoliosis, but were all treated with a triple-rod posterior instrumentation approach. This case series aimed to evaluate the surgical outcomes of the triple-rod technique in patients with severe and rigid scoliosis from various etiologies, including idiopathic, congenital, neuromuscular, and syndromic scoliosis. This study examines the surgical outcomes of the triple-rod technique by evaluating the extent of coronal and sagittal correction achieved, assessing the efficacy of correction in the primary and secondary structural curves of rigid scoliosis, and documenting any intra-operative or post-operative complications.

Methods: This retrospective single-center study analyzed patients with severe and rigid scoliosis treated surgically using the triple-rod technique. Inclusion criteria included a main coronal curve of >90° and a flexibility index of <25%, excluding those with prior traction or spinal surgery. Pre-operative and post-operative radiographs were used to measure curve angles and assess surgical correction. Post-operatively, all patients were monitored for complications, including neurological function, intra-operative neuromonitoring changes, wound infections, and thromboembolic events. Neurological assessments were conducted at regular intervals, evaluating muscle strength, deep tendon reflexes, and sensory responses. Post-operative radiographs were obtained to assess implant positioning, hardware-related issues, curve correction maintenance, and overall spinal alignment.

Results: Eight patients with severe rigid scoliosis underwent surgical correction using the triple-rod technique. The mean age at surgery was 16.3 years (range: 13-24 years). The major coronal Cobb angle improved significantly from a pre-operative mean of 97.9°±7.1° to 51.6°±10.9° post-operatively, while the sagittal Cobb angle improved from 53.9°±23.5° to 35.6°±9.5°. The triple-rod technique demonstrated significant correction, with the main thoracic curve showing the greatest improvement. All cases were completed without complications, including neurological deficits, intra-operative monitoring changes, infections, thromboembolic events, or hardware-related issues.

Conclusions: The triple-rod technique offers an effective solution, providing substantial correction of coronal and sagittal deformities associated with severe rigid scoliosis. Its primary advantage is the ability to achieve a gradual and controlled correction of spinal deformity. This technique helps minimize the risk of neurological complications and other surgical morbidities associated with severe rigid scoliosis surgery.