Split laminotomy versus conventional laminotomy: postoperative outcomes in pediatric patients

OBJECTIVE Split laminotomy is a technique for accessing the spinal canal from the posterior midline that minimizes muscle dissection and bone removal. Benefits of this approach in minimizing postoperative pain and muscle atrophy in the adult population have been reported, but pediatric data are limited. Herein, the authors evaluate the benefits of the split laminotomy technique in pediatric patients. METHODS Data obtained in patients who underwent posterior spine surgery at Children's Hospital of Wisconsin for an intradural midline pathology between April 2008 and June 2015 were reviewed retrospectively. Each patient was assigned to one of two groups, the split-laminotomy or conventional-laminotomy group. The primary outcomes assessed were mean daily pain score, total opioid use over a period of 72 hours after surgery, and the degree of paraspinal muscle atrophy and fat infiltration found on short-term (1-4 months) and long-term (1-4 years) follow-up spine MRI studies. RESULTS A total of 117 patients underwent lumbar-level surgery (83 conventional laminotomy, 34 split laminotomy), and 8 patients underwent thoracic-level surgery (4 in each group). No significant difference in the mean daily pain scores between groups was found. The daily opioid use was significantly lower in the split-laminotomy group on postoperative day 0 (POD0) and POD1 but not on POD2 (p = 0.01, 0.01, and 0.10, respectively). The total opioid use over the 72-hour postoperative period was significantly lower in the split-laminotomy group (p = 0.0008). The fat/muscle ratio was significantly higher in both the short-term and long-term follow-up periods in the conventional-laminotomy group (p = 0.01 and 0.0002, respectively). The rate of change of paraspinal muscle fat infiltration was significantly lower in the split-laminotomy group than in the conventional-laminotomy group (p = 0.007). The incidence of complications was not significantly different between groups (p = 0.08). CONCLUSIONS This study was of the largest series reported thus far of pediatric patients who underwent split laminotomy and the only controlled study that has involved children. The authors' results reinforce the short-term benefit of split laminotomy in minimizing acute postoperative pain and long-term benefits of decreasing muscle atrophy and fatty degeneration, which are known to be associated with the development of chronic pain and spinal instability. Additional efforts for assessing long-term effects in the development of chronic pain, spinal instability, and spinal deformity are still necessary.