Rathjen, Karl E.

Background: Arthrogryposis multiplex congenita is a group of conditions characterized by joint contractures affecting 2 or more joints. This study describes results of spinal fusion in patients with classic amyoplasia and general arthrogryposis. Methods: IRB approved retrospective review of patients with a diagnosis of classic amyoplasia and general arthrogryposis who had a primary definitive posterior spinal fusion between 1990 and 2017 at a single pediatric institution. Patients with distal and syndromic arthrogryposis were excluded as well as patients treated with growth-sparing spinal instrumentation. The Modified Clavien-Dindo-sink (MCDS) classification system was used to describe postoperative complications. Results: Over the 28-year period, 342 patients were diagnosed with amyoplasia and general arthrogryposis. Among the 342 patients, 60 (18%) had scoliosis, and 22 (6% of the cohort and 37% of those with scoliosis) were treated surgically. Six patients had growth-sparing techniques, initial fusion elsewhere, or ˂1 year of follow-up, leaving 15 patients. Of the 15, 9 (60%) had a posterior spinal fusion (PSF) and 6 (40%) had a combined anterior spinal fusion (ASF)/PSF. The ASF/PSF group was significantly younger at surgery, had a greater American Society of Anesthesiologists status, longer surgery duration, and lower implant density. The average preoperative major coronal deformity in ASF/PSF patients (108 degrees) was greater than patients treated with PSF alone (88 deg). There were 11 complications in 7 patients, with the most common being deep infection requiring reoperation (5/11, 45%). There was 1 instance (1/11, 9%) of each: prolonged intensive care unit admission (>72 h), superficial wound dehiscence, symptomatic implants requiring removal/revision, coronal plane progression requiring extension of fusion, recurrent pneumothorax requiring return to OR, and pseudoarthrosis leading to implant failure (without revision). Complications occurred in 1/9 (11%) PSF-only patients and 6/6 (100%) ASF/PSF patients with all 6 ASF/PSF patients requiring at least 1 reoperation. The average coronal correction was 48% in the PSF-only group and 28% in the ASF/PSF group. Conclusion: Complication rates after spinal fusion for scoliosis in arthrogryposis multiplex congenita patients are high, especially in patients undergoing ASF/PSF, deep infection is common, and major coronal plane curve correction is modest. Level of Evidence: II Retrospective Study.

Background: Adjacent segment pathology is a known complication after spinal fusion, but little has been reported on junctional failure. A series of adolescent patients presented with acute distal junctional failure (DJF). We sought to determine any common features of these patients to develop a prevention strategy. Methods: A retrospective review was conducted of pediatric patients who developed DJF after instrumented spinal fusion performed at 2 institutions from 1999 to 2013. Patients with proximal junctional failure or junctional kyphosis without failure were excluded. Results: Fifteen subjects were identified with mean follow-up of 38 months. Distal failure occurred a mean of 60 days after index surgery, with history of minor trauma in 4 patients. Failures included 3-column Chance fracture (11) or instrumentation failure (4). Thirteen patients presented with back pain and/or acute kyphosis, whereas 2 asymptomatic patients presented with healed fractures. Two patients also developed new onset of severe lower extremity neurological deficit after fracture, which improved but never resolved after revision. A total of 13/15 subjects required revision surgery, typically within 1 week. Complications associated with revision surgery were encountered in 8 patients (62%). Major complications that required return to the operating room included 2 deep infections, 2 instrumentation failures, and dense lower extremity paralysis that improved after medial screw revision and decompression. At final follow-up, 10 patients are asymptomatic, 2 have persistent neurological deficit, 2 have chronic pain, and 1 has altered gait with gait aid requirement. Conclusions: This study analyzes a heterogenous cohort of spinal fusion patients who developed DJF from 3-column Chance fracture or instrumentation failure. Revision surgery is typically required, but has a high complication rate and can result in severe neurological deficit, highlighting the morbidity of this complication. It is unclear whether level of the lowest instrumented vertebra contributes to DJF. Increased awareness of junctional failure in children may prompt additional studies to further characterize risk factors and preventative strategies. Level of Evidence: Level IV—study-type case series.