Objective: To improve the safety of the anterior cervical vertebral surgical approach, MRI and CT have been used and the distances between the medial borders of the longus colli (LC) to expose the uncinated process (UP) have been reported. The anatomic parameters of the LC and vertebral artery (VA) were considered here in relation to the UP to minimize complications.Materials and Methods: Data were obtained from 60 Thai adult skeletons and 20 embalmed cadavers. Direct measurements of the dry cervical vertebrae were performed using digital Vernier calipers, while computer imaging analysis was used for the cadaveric measurements after capturing the images.Results: No significant difference was noted in the inter-UP distance between the dry and cadaveric cervical measurements. The average UP width was 6.7 ± 0.2 mm. The average distance from the tip of the UP to the VA was 2.6 ± 0.1 mm. The calculated distance from the LC to the UP which derived from the inter-UP distance and the distance between the LC increased from C2 to C7 with an average distance of 11.9 ± 0.3 mm.Conclusion: Within a distance of 11.9 ± 0.3 mm from the medial border of the LC, UP can be identified. Dissecting at a distance less than 10 mm posterior, 5–6 mm lateral and superior to the base of the UP can avoid VA injury and optimize the safety of the anterior cervical vertebral surgical approach.

Objective: Botulinum toxin (BoTX) injection to the longus colli (LCo) muscle has been demonstrated to have a role in treating cervical dystonic (CD) patients. It can, however, cause critical complications and awareness of such complications is required. Currently, there is no substantial information regarding this novel procedure. This study aims to define the potentially safe method of injection based on assessment of anatomical measurements.Materials and Methods: We examined distances between the puncture sites and adjacent structures in Thiel-embalmed human cadavers (n=20) to propose an alternative technique for BoTX injection. Parameters were examined for the medial and lateral approaches at the fifth and sixth cervical vertebral levels. We compared each variable between the two different vertebral levels and the two different approaches to evaluate statistical differences.Results: Comparing distances between the puncture sites and neck anatomical structures in each of the two approaches, results were statistically significant. Similarly, we found using the medial approach statistical significance when comparing the measurements at the fifth with the sixth cervical vertebral level of the distances between the puncture sites and the thyroidal arteries and recurrent laryngeal nerve (p < 0.05).Conclusion: The present study results provide initial guidelines for the safe technique for BoTX injection into LCo. Our findings suggest that the medial approach at the C6 vertebral level is preferable with minimal injury to vital structures. Thus, it may provide an optional method and can be used as guidance to improve surgical practice. Ethical approval was not required for this study.