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

The Submandibular Approach: A Descriptive Perspective of the Retropharingeal Corridor to the Craniocervical Junction (Microscopic- vs. Endoscopic-Assisted Dissections)

The craniocervical junction refers to an area from the line separating the middle and lower third of the clivus to the base of the dens (anteriorly) and from the posterior edge of the occipital foramen to the spinous process of C2 (posteriorly). Here, the clival region is a challenging surgical target surrounded by a complex neurovascular architecture. Historically, mainly the complex, and high-risk, transmucosal approaches have been the corridors of choice when targeting this region. Nevertheless, the inherent broad anatomic and pathological variants have shown the need for more-malleable and wider approaches. Thus, MacAfee's established retropharyngeal approach has been simplified in parallel to the application of endoscopic surgery, therefore providing access to the clival region through a low-risk retropharyngeal space when compared to homologous anterior transmucosal approaches. The following review analyzes the literature that has specifically described the craniocervical junction after reaching the clivus (or at least after odontoidectomy) through the retropharyngeal corridor, from the perspective of the open approach or the endoscopic submandibular approach.

Atlantoaxial Anterior Transarticular Screw Fixation: Indications and Surgical Technique

Posterior atlantoaxial screw fixation is a widely adopted therapeutic option for C1-C2 instability secondary to fractures or dislocation, degenerative diseases, or tumors at this level. Anterior transarticular screw fixation (ATSF) is an effective alternative to the posterior approaches, presenting several advantages despite being scarcely known and rarely chosen.In this chapter, we describe the ATSF step by step, illustrating its variations reported in literature, and we critically analyze the several advantages and contraindications of this technique. Moreover, we provide a list of tips and tricks on the surgical procedure, including critical operating room settings-the result of more than 10 years of experience in the field by a senior author.ATSF is a valid strategy for the treatment of different diseases occurring at the level of the atlantoaxial complex that needs consideration. Given the significant learning curve of this strategy, some hints may be essential to begin introducing this technique in the personal armamentarium of a spine surgeon so that they can perform ATSF safely and effectively.

Reconstruction after resection of C2 vertebral tumors: A comparative study of 3D-printed vertebral body versus titanium mesh

Background

Surgical resection of C2 vertebral tumors is challenging owing to the complex anatomy of C2 vertebrae and the challenges to surgical exposure. Various surgical approaches are available, but some are associated with excessively high risks of complications. An additional challenge is reconstruction of the upper cervical spine following surgery. In the last decade, additive-manufacturing personalized artificial vertebral bodies (AVBs) have been introduced for the repair of large, irregular bony defects; however, their use and efficacy in upper cervical surgery have not been well addressed. Therefore, in this study, we compared instrumented fixation status between patients who underwent conventional titanium mesh reconstruction and those who underwent the same resection but with personalized AVBs.

Methods

We performed a retrospective comparative study and recruited a single-institution cohort of patients with C2 vertebral tumors. Clinical data and imaging findings were reviewed. Through data processing and comparative analysis, we described and discussed the feasibility and safety of surgical resection and the outcomes of hardware implants. The primary outcome of this study was instrumented fixation status.

Results

The 31 recruited patients were divided into two groups. There were 13 patients in group A who underwent conventional titanium mesh reconstruction and 18 group B patients who underwent personalized AVBs. All patients underwent staged posterior and anterior surgical procedures. In the cohort, 9.7% achieved total en bloc resection of the tumor, while gross total resection was achieved in the remaining 90.3%. The perioperative complication and mortality rates were 45.2% and 6.5%, respectively. The occurrence of perioperative complications was related to the choice of anterior approach (p < 0.05). Group A had a higher complication rate than group B (p < 0.05). Four patients (4/13, 30.8%) developed hardware problems during the follow-up period; however, this rate was marginally higher than that of group B (1/18, 5.6%).

Conclusions

Total resection of C2 vertebral tumors was associated with a high risk of perioperative complications. The staged posterior and retropharyngeal approaches are better surgical strategies for C2 tumors. Personalized AVBs can provide a reliable reconstruction outcome, yet minor pitfalls remain that call for further modification.

Referencing for anterior atlantoaxial trans-articular osteosynthesis: a radiological study and proposal of a decisional algorithm

PURPOSE

Anterior trans-articular C1-C2 screw placement can be considered as a surgical alternative in different conditions affecting the atlantoaxial region. While its rigidity is similar to posterior Magerl and Harms techniques, it also provides some surgical advantages. However, the literature lacks papers exhaustively describing indication criteria, surgical steps, and pitfalls.

METHODS

This is a radiological study on 100 healthy subjects. Thin-layer CT scans of the craniovertebral junction were retrieved from the institutional database. The coronal inclination of the C1-C2 joint rim and the depth of the entry point of the screw with respect to the anterior profile of C2 were measured. The antero-posterior and the medio-lateral surgical corridors for the screw placement, and the wideness of the target area on the upper surface of C1 were also measured.

RESULTS

The multivariate analysis showed that the coronal inclination of the C1-C2 articular joint rim strongly influences the surface extension of the C1 target area; the depth of the entry point and the C1-C2 articular rim inclination seem to be independent factors in influencing both the medio-lateral and the antero-posterior surgical corridors wideness. A decisional algorithm on whether to perform an anterior or posterior approach to the atlantoaxial region was also proposed.

CONCLUSIONS

We can conclude that, as much as the C1-C2 articular rim is tending to the horizontal line, and as deeper is the entry point of the screw on the anterior profile of C2, as easier the anterior C1-C2 trans-articular screw placement will result.

Long-term Radiologic and Clinical Outcomes after Three-level Contiguous Anterior Cervical Diskectomy and Fusion without Plating: A Multicentric Retrospective Study

BACKGROUND

 Anterior cervical diskectomy and fusion (ACDF) has been providing good surgical, clinical, and radiologic outcomes in patients suffering from cervical degenerative disk disease (DDD). However, the role of anterior plating is still debated, especially in three-level procedures. This study aimed to investigate long-term clinical and radiologic outcomes and complications after three-level contiguous ACDF without plating for cervical DDD.

METHODS

 Two institutional databases were retrieved (January 2009-December 2014) for patients treated with three-level contiguous ACDF without plating. Minimum follow-up (FU) was 5 years. Demographical data, smoking status, implant types, Neck Disability Index (NDI), visual analog scale (VAS) for neck pain, complications, fusion rate, adjacent segment degeneration (ASD), cervical lordosis (CL), and residual segmental mobility were evaluated.

RESULTS

 We enrolled 21 patients. Tantalum and carbon fiber cages were implanted, respectively, in 13 and 8 patients. The mean FU length was 5.76 ± 0.87 years. Mean NDI score was 78.29 ± 9.98% preoperatively and 8.29 ± 1.67% at last FU (p < 0.01), whereas mean VAS score decreased from 7.43 ± 1.14 preoperatively to 0.95 ± 0.95 at last FU (p < 0.01). Complications were one postoperative hematoma, one superficial wound infection, and five cases of postoperative dysphagia (recovered within 3 days). The fusion rate was 90% and ASD was reported in three (14%) cases. The mean CL was 6.33 ± 2.70 degrees preoperatively, 8.19 ± 1.97 degrees 3 months after surgery (p = 0.02), and 7.62 ± 1.96 degrees at latest FU. There was no residual mobility on every operated segment at last FU. The smoking status was an independent risk factor for nonfusion in this case series (p = 0.02).

CONCLUSIONS

 Three-level contiguous ACDF without plating seems to be an effective treatment for cervical DDD. Properly designed comparative clinical trials are needed to further investigate this topic.

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.