Morphometric analysis of lumbar pedicles in patients with spinal dysraphism.

BACKGROUND In patients with open neural tube defects, the incidence of scoliosis and requirement for spinal fusions are increased. Historically, there has been no standardized measurement of vertebral morphometry in these patients. However, anecdotally, patients with open neural tube defects have a more medially oriented lumbar pedicle trajectory than the average population. METHODS A single-institution retrospective review of patients with open neural tube defects was conducted. The demographic parameters and functional and anatomical levels of the defects were noted. CT and MRI scans of the lumbar spine were analyzed; the pedicles from L 1 to S 1 were measured for width (W), length (L) and midline angle (α). The measurements were compared bilaterally, at each level, and with data from previously published reports. RESULTS 16 scans of pediatric patients (mean = 3.0 ・} 4.3; age range = 7 days to 14.4 years; 7 males, 9 females) with a diagnosis of either myelomeningocele or lipomyelomeningocele were assessed. Most defects occurred in the lumbar region, with L 2 and L 5 accounting for 37.5% each. All angles demonstrated a quadratic increase from L 1 to S 1 (means: L 1 = 28.3 ・} 5.24° ; L 2 = 29.1 ・} 6.2°; L 3 = 33.2 ・} 6.0°; L 4 = 36.8 ・} 5.6°; L 5 = 43.8 ・} 5.9°; S 1 = 52.0 ・} 3.6°) and were more medially angulated than those reported previously; no significant difference existed between right and left measurements (W = 0.65 ≤ p ≤ 0.94; L = 0.91 ≤ p ≤ 1; α = 0.24 ≤p ≤0.86). CONCLUSIONS Patients with open neural tube defects had more medially angled pedicle trajectories in the lumbar spine when compared to previously reported values.