Association of spinal cord abnormalities with vertebral anomalies: an embryological perspective.

PURPOSE: To analyze the relationship between spinal cord and vertebral abnormalities from the point of view of embryology. METHODS: We analyzed the clinical and radiological data of 260 children with different types of spinal cord malformations in combination with vertebral abnormalities. RESULTS: Among 260 individuals, approximately 109 presented with open neural tube defects (ONTDs), 83 with split cord malformations (SCMs), and 83 with different types of spinal lipomas. Pathological spina bifida emerged as the most frequent vertebral anomaly, affecting 232 patients, with a higher prevalence in ONTD. Vertebral segmentation disorders, including unsegmented bars, butterfly vertebrae, and hemivertebrae, were present in 124 cases, with a higher prevalence in SCM. The third most common spinal anomaly group consisted of various forms of sacral agenesis (58 cases), notably associated with blunt conus medullaris, spinal lipomas, and sacral myelomeningocele. Segmental aplasia of the spinal cord had a typical association with segmental spinal absence (N = 17). CONCLUSION: The association between SCM and neuroenteric cyst/canal and vertebral segmentation disorders is strong. High ONTDs often coincide with pathological spina bifida posterior. Type 1 spinal lipomas and focal spinal nondisjunction also correlate with pathologic spina bifida. Segmental spinal absence or dysgenesis involves localized spinal and spinal cord aplasia, sometimes with secondary filar lipoma.

Easy method to simplify "freehand" subaxial cervical pedicle screw insertion.

STUDY DESIGN: Technical note. OBJECTIVES: The objective of this study is to check out safety and rationality of standardized and fast tricks to select trajectory of subaxial cervical pedicle screw (SCPS) insertion, based on simple angles to bony landmarks. MATERIALS AND METHODS: Stage 1 - Computed tomography (CT)-morphometric analysis of C3-C7 vertebrae of ten patients with cervical degenerative diseases. Stage 2 - SCPS insertion in 6 cadavers, according to the developed technique (59 pedicle screws). Stage 3 - SCPS insertion in 6 patients, according to the developed technique (32 pedicle screws). RESULTS: CT-morphometric analysis showed that the average length of C3-C7 pedicle channels was 32 mm, the average angle between a pedicle axis and an axis of contralateral lamina - 180°, the average angle between a pedicle axis and plane of a posterior surface of a lateral mass amounted to 90° and the coordinates of an optimal entry point - 2 mm from a lateral edge and 2 mm from an upper edge of the lateral mass posterior surface. During the cadaveric study, 39 screws had a satisfactory position (66.1%), 7 screws permissible (11.9%), and 13 screws unacceptable (22%). During the clinical study, 26 screws (81.25%) had satisfactory position, 4 (12.5%) had permissible position, and 2 (6.25%) unacceptable position. CONCLUSION: Developed and clinically approved a method for simplicity SCPS insertion is relatively safe and cheap. No doubt, it requires further investigation, but the results of primary analysis allow us to recommend it to wide practical application.