Frequency and management of rod fractures following minimally invasive bipolar fusionless surgery in neuromuscular scoliosis patients.

Introduction: Neuromuscular scoliosis (NMS) is associated with an abnormal muscle tone. Traditional conservative treatments, with the historical practice of early posterior fusion, have proven ineffective. Recently, growth-sparing techniques have gained traction owing to their ability to maximize trunk height. However, these techniques have a substantial risk of complications, particularly rod breakage, with reported incidence rates ranging from 15 % to 42 %. The objective of this study was to conduct a descriptive analysis of NMS patients who experienced rod breakage following the minimally invasive fusionless surgery (MIFS) technique.

Methods: This was a single-center, retrospective study that included all NMS patients who underwent surgery between January 2015 and January 2021 and subsequently presented with rod breakage after MIFS. The MIFS technique is based on proximal fixation with double hook claws made of pedicular and -sus laminar hooks and pelvic fixation with iliosacral screws.

Results: The mean follow-up was 5.2 ± 2.2 years. The mean dominant etiology of NMS was cerebral palsy (67 %). Of the 217 patients who underwent surgery, 15 (6.9 %) developed rod breakage. Rod breakage occurred 2.7 ± 1.3 years after the initial surgery. Four cases of rod fracture recurrence were reported in ambulatory patients with dystonia or hyperactivity.

Conclusion: Compared with other fusionless techniques, the minimally invasive bipolar technique appears promising for patients with NMS, with a lower rate of rod breakage. We recommend the use of a four-rod construct for ambulatory patients or for those with dystonia or hyperactivity.