Endoscopic Vidian Neurectomy: The Anatomy Consideration and Preoperative Images Analysis

Abstract

IntroductionAlthough surgery is not a primary treatment for manaing rhinitis, it can have some adjuvant benefit in patients with significant nasal congestion or poor pharmacologic response. It is usually performed by surgical approaches to the inferior turbinate, and the more aggressive procedures such as the vidian neurectomy have not been widely applied. Traditional approaches to the vidian canal necessitate larger incisions, including transseptal, transpalatal and transantral methods. These approaches are often not reliable and at the risk of injury to the abutting neurovascular structures. Pioneers in endoscopic surgery are exploring alternatives to these traditional techniques in an attempt to minimize morbidity and the lack of irrelevant incisions. The main difficulties encountered during endoscopic approach are anatomic variations such as canal wall dehiscence, intra-sphenoid septa, pneumatization degree of pterygoid process and the relationship between vidian canal and middle turbinate. Those variations will have effect in determining the surgical success rate and the related complications. Therefore, a powerful tool, in the purpose of identifying the canal location and its surrounding anatomy, is very important to guide the surgeon in preoperative assessment and intraoperative approach. Computed tomography (CT) scanning is superior for the evaluation of the bony confines of the sinonasal tract and skull base. The most minimal recesses of the sinonasal region are easily assessed and it is possible to evaluate the position and configuration of the vidian canal. That valuable information provided by imaging studies enhances the surgical feasibility and offers an alternative for treating the rhinitis. This chapter describes the use of CT images in this capacity. Growing surgical experience and evolving technology will help to advance the feasibility of endoscopic vidian neurectomy and elucidate their indications by using preoperative images.

The anatomic analysis of the vidian canal and the surrounding structures concerning vidian neurectomy using computed tomography scans

“…In this case, if there is no gap between the pterygoid process and the sphenoid process of the palatine bone, one of them is partially removed by transnasal approach. 5 , 7 On the other hand, the prevalence of the PPP was determined as 39.2% (196/500), similar to previous studies results that ranged between 19% and 43.6%. 4 , 11 , 12 Also, we reported that the prevalence of the PPP that facilitates the Type I approach were significantly higher in VC Type 2 (72.4%) and Type 3 (95.8%) as shown in Table 3 ( p < 0.001).…”

“…In other cases, Type II approach was mostly chosen. 4 , 5 The smaller angle between the posterior end of the middle turbinate and the lateral margin of the anterior opening of the VC, no extreme septum deviation, the presence of the gap between the sphenoid process of the palatine bone and the sphenoid bone just medial to the VC significantly increased the success rate of Type II approach. 5 , 6 , 7 The VC corpus types and the PPP which affects the morphometric parameters should be evaluated on preoperative CT scan to avoid iatrogenic injury during endoscopic surgery.…”

“…In the literature, the most common type of pneumatization of the sphenoid sinus was found as the sellar type. 5 , 13 We also observed the pattern of the sphenoid pneumatization and determined as the sellar type (67%). The sellar type pneumatization facilitates all of the endoscopic approaches but, the conchal (nonpneumatized) sphenoid which was found as 1% in our study is a relative contraindication for both types.…”

“…The vidian nerve, which is formed by deep (sympathetic fibers) and greater (parasympathetic fibers) petrosal nerve, courses through the VC that is an important landmark during endoscopic access to the PPF. 5 Especially, for treating the resistant cases of chronic vasomotor rhinitis, the vidian neurectomy interrupts cholinergic innervation of the nasal mucosa by parasympathetic fibers. 6 In previous studies, the endoscopic surgical approaches to the VC were classified as transsphenoidal (Type I) that transected the vidian nerve inside the sphenoid sinus and transnasal (Type II) that is performed in the anterior wall of the sphenoid sinus.…”

“…4 So, preoperative radiological evaluation of the VC corpus types and surrounding sphenoid structures guides the surgeon in choosing an appropriate surgical approach, decreasing complications during endoscopic surgery. 5 …”