Abstract
The K2M MESA Rail is a new implant with a unique beam-like design which provides increased rigidity compared with a standard circular rod of equivalent diameter potentially allowing greater control and maintenance of correction. The aim of this study was to review our early experience of this implant.
We retrospectively reviewed the case notes and radiographs of all consecutive cases of spinal deformity correction in which at least one rail was used. All radiological measurements were made according to the Scoliosis Research Society definitions.
Since June 2012 thirty-three cases of spinal deformity correction were performed using the K2M Rail system. One case was excluded as there were no pre-operative radiographs. Median age was 15 years; there were 23 females. There were 26 scoliosis cases of which two had associated Chiari malformation, three were neuromuscular, and the remainder were adolescent idiopathic cases. Six patients had kyphotic deformity secondary to Scheuermann's disease. Mean length of follow-up was 16 months. In the scoliosis cases the mean pre-operative Cobb angle of the major curve was 58.6° with a mean correction of 35.6°. The mean post-operative thoracic kyphosis was 21.1°. The median number of levels included in the correction was 13. Bilateral rails were used in four cases, the remainder had one rail on the concave side and a contralateral rod. No patients required an anterior release or staged surgery. All kyphosis cases had posterior apical corrective osteotomies. The mean pre-operative thoracic kyphosis was 75.5° with a mean correction of 31°. The median number of levels included in the correction was 11. Four patients had bilateral rails. No patients required anterior release. Complications: two patients had prominent hardware. One patient had a malpositioned screw causing nerve root irritation, which was removed. There were three superficial infections, which settled with antibiotics. There were no cases of implant breakage, screw pull-out, or loss of correction.
The K2M MESA Rail is a powerful new implant design which helps to achieve and maintain satisfactory correction of complex spinal deformity, and is particularly strong at correcting kyphotic deformity. It also enables restoration of normal thoracic kyphosis, particularly in idiopathic thoracic curves, which tend to be lordosing. This may prevent thoracic flat back and potential long-term sequelae. Early results show that the system is as safe and effective as other posterior deformity correction implants on the market, however, it requires further prospective follow-up to ascertain its outcomes in the long-term.
