Experience with definitive instrumented final fusion after posterior-based distraction lengthening in patients with early-onset spinal deformity: single center results.

Limited reports exist with regard to clinical and radiographic details of patients with early-onset spinal deformity (EOSD) undergoing definitive instrumented final fusion (FF) following implantation of a growing construct. Charts and radiographs were queried for all patients who underwent FF after management of EOSD with a distraction-based posterior construct at a single institution from 2006 to 2017. Patients managed during the growth modulation period with either proximal rib or spinal fixation were included. Thirteen patients qualified for inclusion. Spinal deformity etiologies were varied (neuromuscular: 5, idiopathic: 4, congenital: 4). Average age at implantation was 6.5 years, and patients underwent an average of 8.15 lengthening procedures over an average of 69 months. After the growing program, modest correction in main coronal Cobb was obtained at FF (average 52.4° before FF, 37.6° following FF, P<0.001; average percent improvement of 27%). Five patients required posterior column osteotomies. Using criteria proposed by Flynn and colleagues, 'minimal' coronal correction was achieved in 23% of patients and 'moderate' in 77%. No patient achieved 'substantial' (>50%) correction. Subjective poor bone quality was appreciated in 67% of patients, and 85% were noted to have areas of autofusion over previously spanned levels. Two (15%) patients sustained a total of four complications. After growth modulation procedures, EOSD deformities are generally stiff, bone quality is often subjectively poor, and autofusion is common, even after use of proximally rib-based systems. Modestly improved coronal Cobb correction can be obtained at FF but may require single or multiple posterior osteotomies. Intraoperative difficulties can be expected, and clinicians should be alert for intraoperative and postoperative complications.