Minimally invasive lateral mass screws in the treatment of cervical facet dislocations: technical note.
OBJECTIVE: The technique of lateral mass screw and rod or plate fixation is a major advancement in the posterior instrumentation of the cervical spine. This technique provides rigid three-dimensional fixation, restores the dorsal tension band, and provides highly effective stabilization in patients with many types of traumatic injuries. METHODS: Patient 1 was a 32-year-old man who had been in a motor vehicle accident. He presented with right C5 radiculopathy. X-ray findings included 45% anterolisthesis of C4 on C5, bilateral facet disruption, and right unilateral C4-C5 facet fracture and dislocation. The patient was placed in Gardner-Wells tongs, and the fracture was reduced with 25 pounds of traction. Patient 2 was a 56-year-old woman who had been in a motor vehicle accident that resulted in complete quadriplegia. Her initial imaging studies revealed a C3-C4 right unilateral facet fracture with subluxation. She was placed in traction, and her neurological status was reassessed. The findings of her neurological examination revealed improvement: she was found to have Brown-Séquard syndrome. Patient 3 was a 33-year-old man who was involved in a diving accident that resulted in bilaterally jumped facets at C3-C4. The patient was neurologically intact, and attempts at closed reduction were not successful. RESULTS: Patients 1 and 2 underwent anterior cervical discectomy with iliac crest autograft fusion and plating. They were then placed in the prone position, and a dilator tubular retractor system was used to access the facet joint at the level of interest. The facet joints were then denuded and packed with autograft. Lateral mass screws were then placed by means of the Magerl technique, and a rod was used to connect the top-loading screws. Patient 3 underwent posterior surgery that included only removal of the superior facet, intraoperative reduction, and bilateral lateral mass screw and rod placement. CONCLUSION: This technical note describes the successful placement of lateral mass screw and rod constructs with the use of a minimally invasive approach by means of a tubular dilator retractor system. This approach preserves the integrity of the muscles and ligaments that maintain the posterior tension band of the cervical spine.