Background: The transnasal approach to lesions involving the craniovertebral junction represents a technical challenge because of limited inferior exposure. The endoscopic transseptal approach (EtsA) with posterior nasal spine (PNS) removal is described. This technique can create a wide exposure of the craniovertebral junction, thereby increasing the caudal exposure.
Methods: On patients undergoing anterior craniovertebral junction decompression, we calculated the degree of exposure on the sagittal plan through a paraseptal route, an EtsA without and with PNS removal. The horizontal exposure and working area with the latter approach were also evaluated.
Results: Five patients underwent the transnasal procedure. The age of patients ranged from 34-71 years. All patients harbored basilar impression. The mean postoperative Nurick grade (1, 8) was improved versus the average preoperative grade (3). The average follow-up duration was 16 months. All patients underwent occipitocervical fixation. The mean vertical distances, from the clinoid recess to the inferior most limit with the paraseptal approach, EtsA without and with PNS removal were 38.52, 44.12, and 51.16 mm, respectively. The difference between our approach and a standard paraseptal route was statistically significant (P = 0.041; P< 0.05). The mean horizontal distances were 31.68 mm (mononostril entry) and 35.37 mm (binostril entry). The mean working area was 1795.53 mm2.
Conclusions: Endoscopic endonasal approaches to the craniovertebral junction are increasing, but the downward extension on the anterior cervical spine represents a limit. Therefore, many surgeons prefer transoral or transcervical approaches. The EtsA with PNS removal allows for a more caudal exposure than the standard paraseptal approach, with reduced nasal trauma.
Keywords: Endoscopic extended approach to the craniovertebral junction; Endoscopic transnasal approach; Minimally invasive anterior cervical approach; Odontoidectomy.
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