Traditional Growing Rod Instrumentation: Risk-Benefit Analysis of Surgical Intervention Christopher Migdal, BS,1,2 Eric Klineberg, MD,1,2 Joel Lerman, MD, 1,2 Max Haffner, BS, 1,2 Blythe Durbin-Johnson, PhD,1 and Rolando Roberto, MD1,2 1 University of California, Davis, 2 Shriner’s Hospital for Children Northern California INTRODUCTION MATERIALS & METHODS CONCLUSIONS Early onset scoliosis (EOS) can be caused by various syndromes, neuromuscular diseases, or can arise from an unknown, idiopathic origin. If children with severe EOS are left untreated, they are at risk for developing respiratory failure, severe pulmonary hypertension, and cor pulmonale.1 In recent years, the treatment of severe EOS with growing rod implantation (GRI) has become a popular method of treatment. GRI consists of attaching expandable rods across the patient’s scoliotic curve, with the goal of stabilizing the scoliotic curve while allowing for continued chest and spine expansion.2 This expansion is essential, as the thoracic spine and thoracic cage grow rapidly before the age of eight and lung development coincides with and is facilitated by vertical growth of the thoracic spine.3,4 Unfortunately, this process is invasive and poses certain risks for these patients. Along with the inherent dangers and complications associated with surgery, GRI treated children are exposed to anesthesia and radiation with each surgery and throughout their treatment. Increasing radiation exposure from imaging has been linked to increasing cancer risk in children.5 The effect of general anesthesia on the developing brain is equivocal, though it is potentially harmful.6-8 This is a retrospective review of twenty-nine patients who underwent treatment for EOS with GRI at the Shriner’s Hospital for Children Northern California (SHCNC). The inclusion criteria were either: 1) patients treated with who had completed treatment with GRI at SHCNC, or 2) patients who had been undergoing treatment for at least two years with GRI at SHCNC. Of 36 patients treated with GRI at SHCNC, 29 matched these criteria and were included in the study. Patient demographics, number of imaging procedures, anesthesia time, and surgical complications were all acquired from the patients’ medical records. We counted the number of X-ray, fluoroscopic, and CT imaging procedures between the time of initial growing rod implantation and the time of final fusion. Time under anesthesia is defined as beginning upon initial sedation, and ending when the patient is breathing independently. A Linear mixed effects model, including a random effect for subject, were used to estimate the trajectory across multiple procedures of preoperative and postoperative raw Cobb angle and T1-T12 height. Linear mixed effects modeling was conducted using the R package nlme, version 3.1-128.9 All other analyses were conducted using R, version 3.3.1.10 While GRI is an effective treatment for EOS, there are risks associated with the treatment course. In particular, there is considerable potential risk associated with the repeated anesthetics and radiographic imaging. Our model can help weigh the potential risks and benefits in the shared decision-making of initiating, continuing, and completing treatment with GRI. REFERENCES RESULTS Nachemson A. A Long Term Follow-up Study of Non-Treated Scoliosis. Acta Orthop Scand. 2009;39:466-479. Thompson GH, Akbarnia BA, Campbell RM. Growing rod techniques in early-onset scoliosis. J Pediatr Orthop. 27(3):354-361. Karol LA, Johnston C, Mladenov K, Schochet P, Walters P, Browne RH. Pulmonary function following early thoracic fusion in non-neuromuscular scoliosis. J Bone Joint Surg Am. 2008;90(6):1272-128. Dimeglio A, Canavese F. The growing spine: how spinal deformities influence normal spine and thoracic cage growth. Eur Spine J. 2012;21(1):64-70. Kleinerman RA. Cancer risks following diagnostic and therapeutic radiation exposure in children. Pediatr Radiol. 2006;36(S2):121-125. DiMaggio C, Sun LS, Li G. Early childhood exposure to anesthesia and risk of developmental and behavioral disorders in a sibling birth cohort. Anesth Analg. 2011;113(5):1143-1151. Flick RP, Katusic SK, Colligan RC, et al. Cognitive and behavioral outcomes after early exposure to anesthesia and surgery. Pediatrics. 2011;128(5):e1053-6. Glatz P, Sandin RH, Pedersen NL, et al. Association of Anesthesia and Surgery During Childhood With Long-term Academic Performance. JAMA Pediatr. 2016;313(15):e163470. R Core Team. R Package nlme, Version 3.1-128. 2016. http://www.r-project.org/ R Core Team. R version 3.3.1. 2016. http://www.r-project.org/. Risk-Benefit Analysis per Procedure   Hardware Complication/ Unplanned Surgery Wound Complication/ Unplanned Surgery Spine Radiograph/ Chest Radiograph/ Flouroscopy (#) TAT (min) Cobb Correction (deg) T1-T12 gain (cm) Initial (n=29) 3%/0% 7%/7% 4.5/4.0/0.2 305 15 1.6 Lengthening (n=198) 20%/4% 3%/3% 3.3/0.2/0.3 104 0.7 0.4 Final (n=10) 0%/0% 20%/20% 2.3/3.7/0.4 454 3 0.5 Rates listed are per procedure. TAT=Total Anesthesia time, deg=degrees, #=number OBJECTIVES Expand upon the current literature surrounding complications and other potential risks of GRI treatment, focusing on repeated anesthetics and radiographic imaging. Provide a risk-benefit analysis of each GRI procedure that will aid in shared-decision making of initiating, continuing, and completing treatment with GRI. There were 7 idiopathic, 12 syndromic, 6 neuromuscular, and 3 congenital scoliosis patients. There was also 1 patient whose scoliosis was secondary to a large intra-thoracic ganglio-neuroma. On average, patients started treatment at 6.6 years old and were treated for approximately 4 years. Of the 29 patients, 10 patients completed treatment with GRI. These ten patients’ primary Cobb angle reduced on average from 66 degrees to 37 degrees on final films. They each had an average of 31 x-rays, 2 fluoroscopic exams, and 1 CT. They were under general anesthesia for an average of 1,312 minutes for routine scheduled procedures, and if there were implant or wound complications, they were under anesthesia for an additional 155 or 279 minutes, respectively. 60% of the patients had some complication, 50% experienced an implant fracture, and 30% had a wound complication Our linear mixed effects model estimated that although each lengthening procedure roughly decreased the patients’ Cobb angle by 0.7 degrees and increased their T1-T12 height by 0.4 cm, these procedures were associated with a 20% instrumentation complication rate, a 3% wound complication rate, 4 radiographic studies, and 104 minutes under general anesthesia. CONTACT Christopher Migdal cwmigdal@ucdavis.edu Rolando Roberto rfroberto@ucdavis.edu Estimates from linear mixed effects model of the initial preoperative and all postoperative Cobb angles (LEFT) and T1-T12 height (RIGHT) by surgery. The solid line shows the model predicted mean and the dashed lines show the 95% confidence intervals.