Free hand technique of cervical lateral mass screw fixation.

STUDY DESIGN: We introduce a simple free hand technique with great ease of application, without angles, measures or degrees, and without any fluoroscopic guidance. It is a safe and reproducible technique. We present our preliminary experience with the use this technique, with inimitable simplicity. PURPOSE: The primary aim of the procedure was to achieve adequate screw trajectory in an apparent challenging ease which is reproducible with a good outcome. OVERVIEW OF LITERATURE: Lateral mass screw fixation is used for posterior subaxial cervical fixation. It was described by Louis and Magerl, then by Anderson, An, and Ebraheim et al. Each one described the procedure with a unique screw entrance point and trajectory. TECHNICAL NOTE: This study is a prospective case study of 45 patients who underwent subaxial cervical lateral mass screw fixation. The screws were inserted using a free hand method. The described free hand technique was found to minimize the morbidity associated with other techniques without compromising the quality of fixation. CONCLUSIONS: Surgical experiences with this technique found it equally safe, rapid, easy, and reproducible.

Odontoidectomy through posterior midline approach followed by same sitting occipitocervical fixation: A cadaveric study.

OBJECT: Atlantoaxial instability with irreducible odontoid process is one of the challenges in spine surgery. These lesions are commonly treated through anterior transoral approach which is followed by posterior atlantoaxial fusion. However, there are still many limitations, especially cerebrospinal fluid fistula with subsequent life-threatening infection, difficulty in cases with limited opening of mouth due to temporomandibular arthritis or anomalies of naso-oropharynx. Türe et al. used the extreme lateral transatlas approach for the removal of odontoid. In this study, we applied the transatlas approach but through posterior midline incision aiming to evaluate its safety and feasibility. METHODS: In four silicon injected, formalin-fixed cadaver heads, posterior removal of the odontoid was done through the familiar midline incision and subperiosteal muscle separation and elevation of muscles as on unit followed by microscopic exposure and mobilization of the vertebral artery after opening of the foramen transversarium of atlas followed by drilling of lateral mass and odontoidectomy. Occipitocervical stabilization was done between the occiput and C2, C3 (C1 lateral mass screw can be added in the contralateral side for better stabilization). RESULTS: Unilateral excision of the lateral mass of atlas after mobilization of the vertebral artery provided safe and excellent exposure of the odontoid process in the four cadaver heads without injury to vertebral artery or retraction of the dura. CONCLUSION: Posterior removal of the odontoid can be done safely through wide and sterile operative field, and occipitocervical fixation performed at the same sitting without need for another operation and hence avoids the risk of cord injury from repositioning.