Abstract
Introduction: Lumbar spine morphology is well described in healthy children but has not been described in children with Osteogenesis Imperfecta (OI).
Aims: To look at lumbar bony morphometry in OI children and to consider the importance of these factors in spinal surgery in these children
Methods: 21 lumbar vertebrae (from L3-5) of 7 OI (6 OI type 3 and 1 OI type 4) children with scoliosis were analysed using Reformatted Computer Tomographic scans. The following measurements obtained: Spinal canal diameters, Transverse pedicle width, Total pedicle length, Pedicle root length, Transverse pedicle angle and Sagittal pedicle angle. Results are compared with previously published data of normal age-matched lumbar spine measurements
Results: The mean age was 12 years (range 7-18 years). 6 females and 1 male. All had spondylolisthesis at L5-S1. Results were analysed by Wilcoxon Signed Rank test (nonparametric test). The transverse pedicle width was significantly narrower at all 3 levels (p< 0.01). Transverse pedicle angle was significantly less angled at all 3 levels (L3 p=0.04, L4 & L5 p< 0.01) whilst the sagittal pedicle angle was significantly more angled at all 3 levels (p< 0.01). Spinal canal diameter (AP) was significantly increased at all 3 levels (L3 & L5 p< 0.01, L4 p=0.02). And no significant differences in spinal canal transverse diameter and total pedicle length. Pedicle root length Significantly longer at all 3 levels (L3 & L4 p< 0.05, L5 p< 0.01). All children had grade-I spondylolisthesis at L5/S1.
Conclusions: A longer pedicle root with a narrower transverse diameter (and thinner cortices) and a reduced transverse angle is essential knowledge when passing pedicle screws in the lumbar spine in children with OI. This is a difficult technique and its safety requires further evaluation.
Correspondence should be addressed to Mr Carlos Wigderowitz, Senior Lecturer, University Department of Orthopaedic and Trauma Surgery, Ninewells Hospital and Medical School, Dundee DD1 9SY.
