A retrospective chart review was performed to review all the patients who underwent surgery of the craniovertebral junction during a 12-month period at our hospital (UCSF). We included only those with lesions located between the clivus and the body of C2. Eleven patients were identified and included. The medical records were reviewed for demographics and disease-specific information, including age, sex, diagnosis, surgical approach, length of hospital stay (LOS) after surgery, and surgery-related complications. The median age was 54 years (18–64 years). Eight of the patients had an endoscopic approach [endonasal (2), endooral (2), and combined endoscopic transnasal–transoral (4) approaches]. These 8 patients were compared with a contemporary group of 3 patients who had an open, transoral-transpalatal approach for lesions of the craniovertebral junction.
Diagnoses for the endoscopic group included infection (2), tumor (2), rheumatoid arthritis (1), and basilar impression (3). Four of the endoscopic patients had prior transoral surgery at another hospital in the past. All the 3 patients having an open approach had rheumatoid arthritis. None of these 3 had prior C1–C2 surgery.
Early and late postoperative complications were recorded, including documented VPI, dysphagia, need for insertion of percutaneous gastric feeding tube, and airway complications defined as need for endotracheal intubation longer than 24 h, or a tracheotomy as a result of the surgery. Preoperative and postoperative images [computed tomography (CT) and/or magnetic resonance imaging (MRI)] were carefully reviewed for evaluation of the adequacy of resection or decompression.
The data were stored in an excel spreadsheet and transferred to SAS (SAS Institute Inc., Cary, NC, USA) for data analysis by the UCSF Department of Biostatistics, using Fisher's exact test and the Mann-Whitney U test where appropriate.
Surgical technique for endoscopic craniovertebral junction decompression
The patients were positioned supine and were intubated orally and given general anesthesia. Neuromonitoring with somatosensory-evoked potentials was used throughout the procedure. Spinal traction was applied as needed to get the odontoid process into a more normal position. Flouroscopy and neuronavigation were used for surgical guidance.
The endoscopic transnasal approach (endonasal approach) consisted of a bilateral approach through the nostrils. In the expanded form, as described by Kassam et al
] a nasal septal flap was first elevated for closure and then a corridor was prepared with a maxillary antrostomy, ethmoidectomy, middle turbinate resection on the right, posterior septectomy, and a wide sphenoidectomy. However, not all patients required sphenoidectomy or middle turbinectomy, and dissection was tailored to the individual's anatomy. Depending on the location of the lesion, the sphenoid floor and clival bone were drilled to access the craniocervical junction pathology. A midline incision was made with an extended needlepoint cautery through the posterior nasopharygeal mucosa down to the preveterbral fascia. The prevertebral muscles were dissected vertically in the midline and elevated laterally off the spine, which allowed exposure of the anterior tubercle of the atlas. Decompression was then performed using a drill, currettes, and/or Kerrison Rongeur.
The endosocopic transoral approach (endooral approach) was performed with soft palate retraction using 1 or 2 red rubber catheters tied to the uvula and pulled cranially through the nostrils.[12
] The oral cavity and tongue were retracted open with a Spetzler-Sonntag oral retractor. The endoscope was guided under the retracted soft palate to visualize the posterior pharyngeal wall, and the pharyngeal incision was created and continued in the midline to the desired height to expose the C1–C2 area [Figure , ]. The soft tissue and bony structures causing ventral cord compression were resected in a similar fashion to a transnasal decompression, described above [Figure ‐]. The endoscope allowed us to "look" cranially above the level of the soft palate to complete the decompression.
Figure 1 Intraoperative view of the anterior craniovertebral junction, using an endoscopic transoral approach. (a) Linear incision of the pharyngeal mucosa made by Bovie electrocautery. (b) Dissection and exposure of the underlying C1 anterior arch. (c) Drilling (more ...)
For a combined transnasal and transoral approach, the exposure was a combination of the above-mentioned steps in both routes. Then the endoscope and surgical instruments were brought into the surgical field alternatively through the nose and mouth, in order to maximize the exposure with less dissection. Decompression was straightforward because visualization was gained from 2 different angles (from above and below the palate). The most favorable feature gained via combined transnasal and transoral approach is the ability to visualize laterally beyond the confines of the nasal cavity. Such lateral visualization is restricted by the nasal cavity/pterygoid plates in the transnasal-only approach. The addition of the transoral endoscopic approach increased the ability to reach out laterally beyond the confines of the transnasal approach.
CT-based image guidance navigation was typically used for the endoscopic cases. After the pharyngeal incision was completed, surgical dissection was performed with 2 surgeons working in tandem (otolaryngologist and neurosurgeon), one holding the endoscope and retraction while the other performed the dissection and decompression. Visualization of the pulsating dural sac and intraoperative fluoroscopic imaging of instruments placed at the borders of decompression confirmed the extent of the resection.
Closure of the pharyngotomy was performed with absorbable sutures . Tissue sealant and a transnasal merocel sponge were packed in the nose. A transoral feeding tube was then passed under endoscopic guidance. Postoperative CT scans or MRI were performed and adequate decompression was assured in every patient. If the clivus was resected as part of the dissection, a pedicled nasal septal flap was harvested and rotated over the clival defect for closure. This was held in place with an absorbable tissue sealant (DuraSeal, Covidien, Mansfield, MA, USA) and 2 transnasal merocel sponges.