Introduction. Autonomic nerve system (ANS) regulates intercostal vascular nutrition (internal mammary artery), and its pathological status leads to developmental asymmetry of the trunk and rib cage, and consequently producing scoliotic deformity of the spine. The aim of this study is to investigate the possible causation of idiopathic scoliosis in development abnormalities of ANS. Methods. We evaluated samples taken from 12 patients with idiopathic scoliotic deformities and a control set of three patients without scoliotic deformity. We examined the samples of autonomic nerves taken from convexity and concavity of the scoliotic deformity during the patients' surgical correction by the transthoracic approach. We used the electronmicroscopic method to analyse samples, and the morphometric method for statistical evaluation. Results. Evaluation of the samples taken from scoliotic convexity and the control samples of non-scoliotic patients showed normal findings in autonomic nerve structures. We detected significant morphological changes in all scoliotic samples taken from concavity. These changes were mostly in myelin vaginas with abnormalities and compression of the axon fibre, massive lesion and separation of the myelin sheath, vacualisation of cytoplasma of the Schwann cells, and condensation of the cytoblast. By morphometric measurements we found 23·71% of myelinised nerve fibres (MNF), 12·21% of unmyelinised nerve fibres (UNF), and 5·0% of Schwann cells (SC) in samples taken from scoliotic convexity, and 29·9% of MNF, 19·9% of UNF, and 16·7% of SC in control non-scoliotic samples. We recorded 17·36% of MNF, 5·82% of UNF, and 5·27% of SC in samples taken from concavity. Conclusions. We noted abnormalities in structure of ANS in concave side of scoliotic curves, and statistically significant differences between both sides of scoliotic deformity (convexity and concavity). Furthermore, we recorded discrepancies between scoliotic samples and non-scoliotic control samples. The abnormalities, mostly in the myelinated fibres, might be originated by the primary genetic lesion and thus could affect the development of scoliosis. The abnormalities of ANS can produce changes in internal mammary artery, and consequently can lead to the abnormal blood supply of vertebrae as well as anterior wall chest. These abnormalities of ANS could lead to the scoliotic origin in growing spine

Ventral screw osteosynthesis is a common surgical method for treating fractures of the odontoid peg, but there is still no consensus about the number and diameter of the screws to be used. The purpose of this study was to develop a more accurate measurement technique for the morphometry of the odontoid peg (dens axis) and to provide a recommendation for ventral screw osteosynthesis.

Images of the cervical spine of 44 Caucasian patients, taken with a 64-line CT scanner, were evaluated using the measuring software MIMICS. All measurements were performed by two independent observers. Intraclass correlation coefficients were used to measure inter-rater variability.

The mean length of the odontoid peg was 39.76 mm (sd 2.68). The mean screw entry angle α was 59.45° (sd 3.45). The mean angle between the screw and the ventral border of C2 was 13.18° (sd 2.70), the maximum possible mean converging angle of two screws was 20.35° (sd 3.24). The measurements were obtained at the level of 66% of the total odontoid peg length and showed mean values of 8.36 mm (sd 0.84) for the inner diameter in the sagittal plane and 7.35 mm (sd 0.97) in the coronal plane. The mean outer diameter of the odontoid peg was 12.88 mm (sd 0.91) in the sagittal plane and 11.77 mm (sd 1.09) in the coronal plane. The results measured at the level of 90% of the total odontoid peg length were a mean of 6.12 mm (sd 1.14) for the sagittal inner diameter and 5.50 mm (sd 1.05) for the coronal inner diameter. The mean outer diameter of the odontoid peg was 11.10 mm (sd 1.0) in the sagittal plane and 10.00 mm (sd 1.07) in the coronal plane. In order to calculate the necessary screw length using 3.5 mm cannulated screws, 1.5 mm should be added to the measured odontoid peg length when anatomical reduction seems possible.

The cross-section of the odontoid peg is not circular but slightly elliptical, with a 10% greater diameter in the sagittal plane. In the majority of cases (70.5%) the odontoid peg offers enough room for two 3.5 mm cannulated cortical screws.

Cite this article: Bone Joint J 2013;95-B:536–42.