Intrathecal baclofen pumps do not accelerate progression of scoliosis in quadriplegic spastic cerebral palsy.

PURPOSE: To compare scoliosis progression in quadriplegic spastic cerebral palsy with and without intrathecal baclofen (ITB) pumps. METHODS: A retrospective matched cohort study was conducted. Patients with quadriplegic spastic cerebral palsy, GMFCS level 5, treated with ITB pumps with follow-up >1 year were matched to comparable cases by age and baseline Cobb angle without ITB pumps. Annual and peak coronal curve progression, pelvic obliquity progression and need for spinal fusion were compared. RESULTS: ITB group: 25 patients (9 female), mean age at pump insertion 9.4 and Risser 0.9. Initial Cobb angle 25.6° and pelvic tilt 3.2°. Follow-up 4.3 (1.0-7.8) years. Cobb angle at follow-up 76.1° and pelvic tilt 18.9°. Non-ITB group: 25 patients (14 female), mean age at baseline 9.2 and Risser 1.0. Initial Cobb angle 29.7° and pelvic tilt 7.1°. Follow-up 3.5 (1.0-7.5) years. Cobb angle at follow-up 69.1° and pelvic tilt 21.0°. The two groups were statistically similar for baseline age, Cobb angle and Risser grade. Mean curve progression was 13.6°/year for the ITB group vs 12.6°/year for the non-ITB group (p = 0.39). Peak curve progression was similar between the groups. Pelvic tilt progression was comparable; ITB group 4.5°/year vs non-ITB 4.6°/year (p = 0.97). During follow-up 5 patients in the ITB group and 9 in the non-ITB group required spinal fusion surgery for curve progression (p = 0.35). CONCLUSIONS: Patients with quadriplegic spastic cerebral palsy with and without ITB pumps showed significant curve progression over time. ITB pumps do not appear to alter the natural history of curve progression in this population.

Upper arm length model suggests transient bilateral asymmetry is associated with right thoracic adolescent idiopathic scoliosis (RT-AIS) with implications for pathogenesis and estimation of linear skeletal overgrowth.

INTRODUCTION: In girls with adolescent idiopathic scoliosis (AIS) the finding of abnormal extra-spinal bilateral skeletal length asymmetries in upper limbs, periapical ribs, and ilia begs the question whether these bilateral asymmetries are connected in some way with pathogenesis. MATERIAL AND METHODS: We investigated upper arm length (UAL) asymmetries in two groups of right-handed girls aged 11-18 years with right thoracic adolescent idiopathic scoliosis (RT-AIS, n=95) from preoperative and screening referrals (mean Cobb angle 46°) and healthy controls (n=240). Right and left UAL were measured with a Harpenden anthropometer of the Holtain equipment, Asymmetry was calculated as UAL difference, right minus left, in mm. Repeatability of the measurements was assessed as technical error of the measurement and coefficient of reliability. RESULTS: In girls with RT-AIS, UAL asymmetry was greater than in healthy girls, regressed negatively with age and correlated significantly with Cobb angle and apical vertebral rotation. In healthy girls, UAL asymmetry was unrelated to age. Plotted against years after estimated menarcheal age, UAL asymmetry decreased significantly for girls with RT-AIS but not for healthy girls. DISCUSSION AND CONCLUSIONS: The apparent transience of the abnormal UAL asymmetry suggests it is not secondary to spinal deformity but pathogenetically associated with it. We suggest two hypotheses to account for these changes: (1) a transient asymmetry process with growth velocity; and (2) in the light of subsequent research, early skeletal overgrowth with catch-down growth affecting right but not left upper arm. The relation of the upper arm length asymmetry to the increased length of periapical left ribs reported for RT-AIS is unknown. Right upper arm length may provide a more simple model than arm span, for estimating linear skeletal overgrowth of girls with RT-AIS.

Pathogenesis of adolescent idiopathic scoliosis in girls - a double neuro-osseous theory involving disharmony between two nervous systems, somatic and autonomic expressed in the spine and trunk: possible dependency on sympathetic nervous system and hormones with implications for medical therapy.

Anthropometric data from three groups of adolescent girls - preoperative adolescent idiopathic scoliosis (AIS), screened for scoliosis and normals were analysed by comparing skeletal data between higher and lower body mass index subsets. Unexpected findings for each of skeletal maturation, asymmetries and overgrowth are not explained by prevailing theories of AIS pathogenesis. A speculative pathogenetic theory for girls is formulated after surveying evidence including: (1) the thoracospinal concept for right thoracic AIS in girls; (2) the new neuroskeletal biology relating the sympathetic nervous system to bone formation/resorption and bone growth; (3) white adipose tissue storing triglycerides and the adiposity hormone leptin which functions as satiety hormone and sentinel of energy balance to the hypothalamus for long-term adiposity; and (4) central leptin resistance in obesity and possibly in healthy females. The new theory states that AIS in girls results from developmental disharmony expressed in spine and trunk between autonomic and somatic nervous systems. The autonomic component of this double neuro-osseous theory for AIS pathogenesis in girls involves selectively increased sensitivity of the hypothalamus to circulating leptin (genetically-determined up-regulation possibly involving inhibitory or sensitizing intracellular molecules, such as SOC3, PTP-1B and SH2B1 respectively), with asymmetry as an adverse response (hormesis); this asymmetry is routed bilaterally via the sympathetic nervous system to the growing axial skeleton where it may initiate the scoliosis deformity (leptin-hypothalamic-sympathetic nervous system concept = LHS concept). In some younger preoperative AIS girls, the hypothalamic up-regulation to circulating leptin also involves the somatotropic (growth hormone/IGF) axis which exaggerates the sympathetically-induced asymmetric skeletal effects and contributes to curve progression, a concept with therapeutic implications. In the somatic nervous system, dysfunction of a postural mechanism involving the CNS body schema fails to control, or may induce, the spinal deformity of AIS in girls (escalator concept). Biomechanical factors affecting ribs and/or vertebrae and spinal cord during growth may localize AIS to the thoracic spine and contribute to sagittal spinal shape alterations. The developmental disharmony in spine and trunk is compounded by any osteopenia, biomechanical spinal growth modulation, disc degeneration and platelet calmodulin dysfunction. Methods for testing the theory are outlined. Implications are discussed for neuroendocrine dysfunctions, osteopontin, sympathoactivation, medical therapy, Rett and Prader-Willi syndromes, infantile idiopathic scoliosis, and human evolution. AIS pathogenesis in girls is predicated on two putative normal mechanisms involved in trunk growth, each acquired in evolution and unique to humans.