Original Research Natural History of Scoliosis in Nonambulatory Spastic Tetraplegic Cerebral Palsy Yaoming Gu, MD, MS, Jean E. Shelton, MD, Jessica M. Ketchum, PhD, David X. Cifu, MD, Dorothy Palmer, MD, Ann Sparkman, LPN, Melinda K. Jermer-Gu, OTR, Marianne Mendigorin Objective: To analyze the development and progression of scoliosis in children and adolescents with nonambulatory spastic tetraplegic cerebral palsy. Design: Retrospective longitudinal review. Setting: Pediatric nursing home. Participants: A total of 110 children and adolescents 18 years of age, with scoliosis. Interventions: N/A. Main Outcome Measures: Cobb angle, age, weight, height, history of hip dislocation, tracheostomy. Results: The Cobb angle increased with age, weight, and height in a nonlinear fashion. A square root transformation of the Cobb angle was chosen to model the nonlinear relation- ship between the Cobb angle and predictors. Age, height, and weight were significant univariate predictors of the square root of the Cobb angle (slopes = 0.377, 0.067, and 0.06, respectively). In the multivariate mixed model, age remained a significant predictor of the Cobb angle (slope = 0.456), but height and weight did not. If the Cobb angle was 40° by age 12 years, scoliosis was more likely to progress than if the Cobb angle was 40°. The effect of age was stronger for those with history of tracheostomy (age slope = 0.631 vs 0.281) than those without. The relationship of age and Cobb angle did not differ signifi- cantly between hip dislocated and non– hip-dislocated groups. Conclusions: Age was found to be the most significant predictor of Cobb angle, and the effect of age was greater in the tracheostomy group than in the nontracheostomy group. After adjustment for age, the weight and height were not significant predictors of Cobb angle. Cobb angles of 40° by the age of 12 years were associated with greater increases in Cobb angle with age. PM R 2011;3:27-32 INTRODUCTION The prevalence of cerebral palsy (CP) is 1.9 to 2.6 per 1000 births [1]. Prematurity is 1 of the major causes of CP [2]. Among individuals who have a gestational age of 20 to 25 weeks, CP prevalence increases to 19 per 1000 live births. Scoliosis appears more frequently and with greater severity in children with CP as compared with healthy children [3]. The estimated incidence of scoliosis in CP ranges from 25% to 64% in institutionalized patients [4,5]. There are few studies in which investigators researched the natural history of scoliosis in children with CP [5-9]. Many factors influence the severity of scoliosis. Factors that predict the progression of scoliosis are early onset of curvature and the severity of the CP [5,8]. Scoliosis continues to worsen even after bone maturity [9]. The severity of CP seems to play a major role in the progression of the curvature. This association appears to be multifactorial [5]. Asymmetric spasticity of paraspinal musculature may force the spine to the contralateral side and result in scoliosis. In addition, hip dislocation may affect the pelvic obliquity and begin the curvature of the spine that results in scoliosis. However, muscle release below the iliac crest does not seem to stop the progression of scoliosis [10]. Overall, the mechanism that triggers scoliosis in CP remains unclear. The reason that scoliosis continues to worsen after bone maturity has also not been defined. Experimental Y.G. VCU Spine Center, Virginia Common- wealth University, 8700 Stony Point Park- way, Suite 260, Richmond, VA 23235. Address correspondence to Y.G.; e-mail: ygu@vcu.edu Disclosure: nothing to disclose J.E.S. Department of Physical Medicine & Re- habilitation, Eastern Virginia Medical School, Norfolk, VA Disclosure: nothing to disclose J.M.K. Department of Biostatistics, Virginia Commonwealth University, Richmond, VA Disclosure: nothing to disclose D.X.C. Department of Physical Medicine & Rehabilitation, Virginia Commonwealth Uni- versity, Richmond, VA Disclosure: nothing to disclose D.P. Department of Physical Medicine & Re- habilitation, Eastern Virginia Medical School, Norfolk, VA Disclosure: nothing to disclose A.S. St. Mary Infant Home, Norfolk, VA Disclosure: nothing to disclose M.K.J.-G. Sheltering Arms Hospital, Rich- mond, VA Disclosure: nothing to disclose M.M. St. Mary Infant Home, Norfolk, VA Disclosure: nothing to disclose Presented in part at the American Academy of Physical Medicine and Rehabilitation annual meeting, November 2008, San Diego, CA. Submitted for publication December 22, 2008; accepted September 22, 2010. PM&R © 2011 by the American Academy of Physical Medicine and Rehabilitation 1934-1482/11/$36.00 Vol. 3, 27-32, January 2011 Printed in U.S.A. DOI: 10.1016/j.pmrj.2010.09.015 27