Posterior instrumentation and fusion in myelomeningocele scoliosis: evaluation of posterior instrumentation and fusion surgery results in spinal curves with two or more consecutive lamina defects

The aim of this study is to report the results of scoliosis surgery in myelomeningocele (MMC) patients with posterior lamina defects (PLD) who had isolated posterior instrumentation/fusion (PIF) with all pedicle screw. Twenty scoliotic patients with myelomeningocele were included in the study. Patients who had two or more levels of PLD, PIF with all pedicle screw construct and post-operative follow-up of at least two years were included. Pure kyphotic patients were excluded. Ten out of 20 patients had thoracic level myelomeningocele. The mean follow-up was 52±29 months. The mean number of spinal levels with posterior lamina defects was 4.7±2.2. Mean blood loss and operative time were 1558±933 ml and 351±47 minutes. Pre and post-operative Cobb angles of the main curve was 86°±26° and 43°±27°, respectively. Correction rate of the main curve was 54±21%. The rates of pseudoarthrosis, infection and implant related complication were 10%, 25% and 50%, respectively. Based on Clavien-Dindo classification, 15% of patients had grade1, 20% grade2, 55% grade3 and 10% grade4 complications. Infection rate was significantly higher in thoracic level patients (p<0.05). Although grade 3 complications were higher in patients with 4 or more level of lamina defects, thoracic level MMC, non-ambulatory patients and in patients with pelvic instrumentation there was no statistical difference (p>0.05). MMC scoliosis with PLD can effectively be treated with PIF. Pseudoarthrosis rate is low. Although the procedure is associated with high rate of implant related complications, most of them can be managed with simple surgical procedures. Keywords: Myelomeningocele, scoliosis, posterior instrumentation and fusion, all pedicle screw construct, lamina defect.