X-ray exposure in odontoid screwing for Anderson type II fracture: comparison between O-arm and C-arm-assisted procedures.

BACKGROUND: Since the odontoid fractures become increasingly common in the aging population, technical improvements are even more needed. The odontoid screwing has been progressively preferred by many surgeons in type II fractures according to the Anderson-D'Alonzo classification system. However, X-ray exposure remains an issue for surgeons and OR staff members. The aim of the present study was to investigate the feasibility of using the O-Arm for odontoid screwing comparing the radiation exposure to the standard C-Arm. METHODS: Patients consequently referred to our center for odontoid type II fractures, from January 2018 to April 2019, eligible for odontoid screwing were enrolled in the present study. They were operated on using either C-Arm or O-Arm-assisted procedures. The surgical duration, number of acquisitions, global X-ray exposure for the OR staff and patients, and screw placement accuracy were evaluated. RESULTS: No differences in terms of patients' demographical characteristics and surgical duration were reported. The number of acquisitions, intraoperative and global X-ray dose, for the OR staff and patients, was lower in O-Arm-assisted procedures (p < 0.05). The screws were all well positioned. CONCLUSIONS: Since the surgical outcomes seem to be similar using the O-Arm for odontoid screwing, the lower X-ray exposure and the possibility for checking the instrumentation positioning with 3D reconstructions before leaving the OR should be considered.

Submandibular Approach for Single-Stage Craniovertebral Junction Ventral Decompression and Stabilization: A Preliminary Cadaveric Study of Technical Feasibility.

BACKGROUND: The craniovertebral junction (CVJ) may be affected by several diseases. It is an anatomically complex region, involving the osteoligamentous, vascular, and nervous structures, which makes surgery challenging. In a case of ventral compression, an anterior approach is preferable, although posterior fixation is often required. Anterior transmucosal approaches are associated with high rates of complications. However, decompression and fixation by the use of retropharyngeal extramucosal approaches may be challenging. OBJECTIVE: To investigate the feasibility of a single-stage, anterior, extramucosal submandibular (SM) approach modification to the CVJ for simultaneous decompression and stabilization. MATERIALS AND METHODS: This was a preliminary cadaveric feasibility study on 2 injected specimens. A variation of the SM approach with a short "boomerang" incision, microsurgical decompression of the ventral CVJ, and a new hybrid construct for an anterior atlantoaxial stabilization was investigated. The surgical approach, the decompression, and the instrumentation technique have been described. In addition, intraprocedural images and radiographs and also postprocedural computed tomographic images were collected. Furthermore, surgical exposure, working corridors and angles, and decompression grade were measured. RESULTS: The SM approach provided wide exposure of the ventral CVJ and the possibility for instrumentation and decompression by removing the anterior arch of C1 and the odontoid process. CONCLUSION: A single- stage anterior extramucosal SM approach for decompression and stabilization of the CVJ is feasible and could result in shorter surgical duration, avoiding the complications related to both the transmucosal approach and the prone position, although specific related risks exist. Mechanical investigation of this hybrid system and in vivo studies are needed to confirm our results.

Atlantoaxial anterior transarticular screw fixation: a case series and reappraisal of the technique.

BACKGROUND CONTEXT: Atlantoaxial instability is commonly treated with C1-C2 fixation performed via posterior approaches. Although anterior transarticular screw (ATS) fixation, performed with a classic retropharyngeal approach, was described more than 10 years ago, the published literature still lacks a comprehensive analysis of the procedure and a real case series. PURPOSE: We report a series of patients treated with atlantoaxial ATS, describing the surgical procedure in detail and discussing advantages and disadvantages of the technique. STUDY DESIGN: The study design includes case series and technical report. METHODS: We prospectively enrolled 15 patients affected by atlantoaxial instability secondary to trauma, degenerative diseases, or inflammatory diseases. Anterior transarticular screw fixation was performed with anteroposterior open-mouth and lateral intraoperative radiographs. All patients were evaluated radiologically at follow-up to identify bone fusion. RESULTS: Anterior transarticular screw was performed successfully in 14 patients without complications. The procedure was aborted in a case of vertebral invagination, and one case required revision surgery owing to C2 articular bone fracture. Solid C1-C2 fusion was achieved in all cases (at 10- to 21-week follow-up) except in an elderly patient affected by severe osteoporosis. No complications occurred. CONCLUSIONS: Although the procedure is still not widely known, ATS allows the effective and safe treatment of C1-C2 instability even in patients with systemic comorbidities. It offers several advantages over posterior approaches.