The use of growth-sparing instrumentation in pediatric spinal deformity is associated with a significant incidence of adverse events. However, there is no consistent way to report these complications, allowing for meaningful comparison of different growth-sparing techniques and strategies. The purpose of this study is to develop consensus for a new classification system to report these complications.
The authors, who represent lead surgeons from 5 major pediatric spine centers, collaborated to develop a classification system to report complications associated with growing spine surgery. Following IRB approval, this system was then tested using a minimum of 10 patients from each center with at least 2-year follow-up after initial implantation of growing instrumentation to assess ease of use and consistency in reporting complications. Inclusion criteria were only patients who had surgical treatment of early onset scoliosis and did not include casting or bracing.
Complications are defined as an unplanned medical event in the course of treatment that may or may not affect final outcome. Severity refers to the level of care and urgency required to treat the complication, and can be classified as device related or disease related. Severity grade (SV) I is a complication that does not require unplanned surgery, and can be corrected at the next scheduled surgery. SVII requires an unplanned surgery, with SVIIA requiring a single trip and SVIIB needing multiple trips for resolution. SVIII is a complication that substantially alters the planned course of treatment. Disease-related complications are classified as grade SVI if no hospitalization is required and grade SVII if hospitalization is required. SVIV was defined as death, either disease or device related.
A total of 65 patients from 5 institutions met enrollment criteria for the study; 56 patients had at least 1 complication and 9 had no complications. There were 14 growing rods, 47 VEPTRs, ,and 4 hybrid constructs. The average age at implant was 4.7 years. There were an average of 5.4 expansions, 1.6 revisions, and 0.8 exchanges per patient. The minimum follow-up was 2 years. The most common complications were migration (60), infection (31), pneumonia (21), and instrumentation failure (23). When classified, the complications were grade I (57), grade IIA (79), grade IIB (10), and grade III (6).
Well-documented uncertainty in clinical decision making in this area highlights the need for more rigorous clinical research. Reporting complications standardized for severity and impact on the course of treatment in growing spine surgery is a necessary prerequisite for meaningful comparative evaluation of different treatment options. This study shows that although complications were common, only 9% (SVIII) were severe enough to change the planned course of treatment.
We propose that future studies reporting complications of different methods of growth-sparing spine surgery use this classification moving forward so that meaningful comparisons can be made between different treatment techniques.