Vidian neurectomy-some technical remarks

The anatomical and radiological evaluation of the Vidian canal on cone-beam computed tomography images

INTRODUCTION

The aim of this study is to explore the anatomy of the Vidian nerve to elucidate the appropriate surgical approach based on preoperative cone-beam computed tomography (CBCT) images.

MATERIALS AND METHODS

The Vidian canal and its surrounding structures were morphometrically evaluated retrospectively in CBCT images of 400 cases by the Planmeca Romexis program. The types of the Vidian canal were determined and seven parameters were measured from the images.

RESULTS

Three types of the Vidian canal according to the relationship with the sphenoid bone were found as follows: the Vidian canal totally protruded into the sphenoid sinus (19.75%), partially protruded into sphenoid sinus (44.37%) and embedded inside bony tissue of the body of sphenoid bone (35.87%). The position of the Vidian canal was medial (34.62%), on the same line (55.12%) and lateral (10.25%) to the medial plate of the pterygoid process. The distance between the Vidian canal and the vomerine crest, the mid-sagittal plane, the round foramen, the palatovaginal canal, and the superior wall of the sphenoid sinus, the length of the Vidian canal and the angle between the Vidian canal and the sagittal plane was found to be 16.69 ± 2.14, 13.80 ± 2.00, 8.88 ± 1.60, 5.83 ± 1.37, 23.98 ± 2.68, 13.29 ± 1.71 mm and 25.78° ± 3.68° in males, 14.62 ± 1.66, 11.43 ± 1.28, 8.51 ± 1.63, 5.78 ± 0.57, 22.37 ± 2.07, 12.91 ± 1.26 mm and 23.43° ± 3.07° in females, respectively.

CONCLUSIONS

Our results may assist with proper treatment for surgical procedures around the Vidian canal with a high success rate and minimal complications. Therefore, the results obtained in this study contribute to the literature.

Endoscopic Vidian Neurectomy

Background

Vidian neurectomy has in the past been advocated for the treatment of vasomotor rhinitis. With the recent better understanding of nasal and sinus anatomy, the surgical technique and outcomes of this procedure have been reassessed in this preliminary report.

Methods

A total of nine patients with symptoms of vasomotor rhinitis underwent 14 endoscopic vidian neurectomies between 1998 and 2001. All patients had negative screening for allergies on their serum or on skin-prick tests. The surgical technique for endoscopic vidian neurectomy is presented. The outcomes for the patients were retrospectively assessed with patients asked to score their pre- and postoperative symptoms rating these symptoms on a scale of 1–10 after a mean follow-up of 25 months (range, 21–36 months).

Results

On this retrospective analysis there was a significant improvement in the symptoms of rhinorrhea (p = 0.018) and nasal obstruction (p = 0.011). There was no significant difference between the pre- to postoperative symptoms for postnasal drip or sneezing. The most common minor adverse effect was dry eyes (35.7%) and nasal crusting (28.6%).

Conclusion

Endoscopic vidian neurectomy improves the symptoms of nasal obstruction and rhinorrhea in patients with vasomotor rhinitis.

Dissection and exposure of the whole course of deep nerves in human head specimens after decalcification

The whole course of the chorda tympani nerve, nerve of pterygoid canal, and facial nerves and their relationships with surrounding structures are complex. After reviewing the literature, it was found that details of the whole course of these deep nerves are rarely reported and specimens displaying these nerves are rarely seen in the dissecting room, anatomical museum, or atlases. Dissections were performed on 16 decalcified human head specimens, exposing the chorda tympani and the nerve connection between the geniculate and pterygopalatine ganglia. Measurements of nerve lengths, branching distances, and ganglia size were taken. The chorda tympani is a very fine nerve (0.44 mm in diameter within the tympanic cavity) and approximately 54 mm in length. The mean length of the facial nerve from opening of internal acoustic meatus to stylomastoid foramen was 52.5 mm. The mean length of the greater petrosal nerve was 26.1 mm and nerve of the pterygoid canal was 15.1 mm.

Historical, pathophysiological, and therapeutic aspects of vidian neurectomy

Vidian neurectomy yields dramatic relief of nasal hypersecretion in patients with allergic rhinitis. Clinical studies conducted on vidian neurectomized nasal mucosa have shown that nasal hypersecretion observed after challenging the nasal mucosa with antigen is caused by reflexively induced activation of the parasympathetic center secondary to stimulation of the sensory nerve terminals in the nasal mucosa by histamine. On the contrary, nasal mucosal swelling is caused mostly by the direct effects of chemical mediators on the nasal vasculature, although vascular reflex mediated by the noncholinergic parasympathetic nerve may be partially involved in the onset of nasal mucosal swelling after antigen challenge. Considering the long-term side effects of inhibition of lacrimation and possible partial recurrence of hyperreactive nasal symptoms observed after vidian neurectomy, less invasive endoscopic posterior nasal neurectomy is considered the treatment of choice for patients with allergic rhinitis who require surgical intervention.

Expanded endonasal approach: vidian canal as a landmark to the petrous internal carotid artery

The purpose of this study was to describe the technique used to safely identify the petrous carotid artery during expanded endonasal approaches to the skull base. A series of 20 cadaveric studies was undertaken to isolate the vidian artery and nerve and to use them as landmarks to the petrous internal carotid artery (ICA). Twenty-five consecutive paraclival endoscopic cases were also reviewed to determine the consistency of the vidian artery in vivo as an intraoperative landmark to the ICA. These data were then correlated with results from a separate study in which computed tomography scans from 44 patients were evaluated to delineate the course of the vidian canal and its relationship to the petrous ICA. In all 20 cadaveric dissections and all 25 surgical cases, the vidian artery was consistently identified and could be reliably used as a landmark to the ICA. The correlation between anatomical and clinical data in this paper supports the consistent use of the vidian artery as an important landmark to the petrous ICA.

Vidian canal: analysis and relationship to the internal carotid artery

OBJECTIVES

The purpose of this study is to describe the anatomy and relationships of the vidian canal to known endonasal and skull base landmarks. This will allow the endoscopic skull base surgeon to safely approach the anterior genu of the petrous carotid artery during expanded endonasal approaches to the skull base.

STUDY DESIGN

The study is a prospective cohort study.

METHODS

Axial, coronal, and sagittal computed tomography scans of the paranasal sinuses and skull base of 44 patients were examined. Individuals with known skull base pathology were excluded. Measurements included the length of the vidian canal, the relationship of the vidian canal to the anterior genu of the petrous carotid artery, and the type of pneumatization of the sphenoid sinus as it pertains to foramen rotundum and the vidian canal. In addition, we will focus on the relationship of the vidian canal to the sphenopalatine foramen and base of the medial pterygoid plate.

RESULTS

The degree of pneumatization of the sphenoid sinus is highly variable. The mean length of the vidian canal is 18 mm (10-23 mm). The vidian canal is found entirely within bone in 27% to 30% of scans reviewed. The anterior genu of the petrous internal carotid artery is found superior-medial to the vidian canal in 44 of 44 of the CT scans reviewed. The vidian canal runs medial to lateral in 93% to 98% of patients studied.

CONCLUSIONS

As a result of this study the endoscopic skull base surgeon has a number of anatomical landmarks and measurements that may be helpful in safely localizing the anterior genu of the petrous internal carotid artery during expanded endonasal approaches to the skull base.

Laser treatment of hyperplastic inferior nasal turbinates: a review

BACKGROUND AND OBJECTIVE

Since the early 80s various types of lasers have been used for the reduction of hyperplastic inferior nasal turbinates. Up to now many studies have revealed a variety of important information. To summarize these findings and to determine the value of laser treatment of hyperplastic inferior nasal turbinates, a comparative review of the literature was performed.

STUDY DESIGN/MATERIALS AND METHODS

The study of the literature revealed that hyperplastic inferior turbinates of more than 2,000 patients have been treated and followed up. Treatment was performed with the CO2 (10,600 nm), diode (805/810/940 nm), Argon-ion (488/514 nm), KTP (532 nm), Nd:YAG (1,064 nm), and Ho:YAG (2,080 nm) laser in more than 20 studies so far. Generally, the authors of the trials used different laser parameters (power, energy) and application modalities (contact, non-contact, interstitial, superficial). To determine the long-term results objective (active anterior rhinomanometry, acoustic rhinometry, mucociliary function tests, allergy tests) as well as subjective parameters (questionnaire) were recorded and evaluated. In some cases morphological changes of the turbinate tissue were studied by light and scanning electron microscopy (SEM).

RESULTS

Laser surgery of inferior turbinates can be performed as an outpatient procedure under local anesthesia. Due to a minimally invasive and controllable coagulation and ablation of soft tissue, almost no complications or bleedings were observed during the operation or postoperatively. Depending on the chosen parameters (power, energy) and the application modalities (contact, non-contact, superficial, interstitial) laser treatment of hyperplastic inferior nasal turbinates achieved comparable or better results than most of the conventional techniques for turbinate surgery like conchotomy, electrocautery, cryotherapy, chemical cauterization, and vidian neurectomy. More invasive (radical) operative methods, such as inferior turbinoplasty, submucous turbinectomy, lateral outfracture, partial and total turbinectomy, seemed to be more effective than laser surgery in the long-term.

CONCLUSIONS

Laser treatment of hyperplastic inferior nasal turbinates can be considered as a useful, cost-effective, and time-saving procedure for the reduction of hyperplastic inferior nasal turbinates. Short operation time, good results, and minor side effects compared to other surgical methods provide an excellent clinical response of the patients.

Endoscopic surgery of the vidian nerve. Preliminary report

The anatomy, surgical technique, and difficulties of endoscopic vidian neurectomy are described. The procedure was carried out on 12 patients: 8 had resistant secretomotor rhinopathy and 4 had recurrent nasal polyposis. This technique is a minor surgical procedure with symptomatic relief and minimal postoperative morbidity.

Clinical evaluation of vidian neurectomy for nasal allergy

For the clinical evaluation of vidian neurectomy, questionnaires were sent to 250 cases operated on from 1971 to 1982, with answers obtained from 171. For sneezing, 56.8% of cases were evaluated markedly effective, 36.7% effective, 4.3% unchanged, and 2.2% aggravated. For rhinorrhea, markedly effective was 54.7%; effective, 39.4%; unchanged, 3.7%; aggravated, 2.2%. For nasal obstruction, markedly effective was 67.5%; effective, 27.4%; unchanged, 5.1%; and aggravated, 0%. On the other hand, 20% of cases complained of relapse of nasal allergic symptoms. Concerning the side effects, 28.7% of cases complained of cheek, upper lip, or palate numbness. Decrease of lacrimation was noted in 9.4% of cases. Several kinds of disturbances in the eye movement were observed in 4% of cases. Among them, 16 cases showed complete recovery within 24 h. In 3 cases, abducens paralysis continued for several months. Postoperative arterial bleeding occurred in one case. My recent strategy for the treatment of allergic rhinitis is conservative treatment at first, secondary nasal surgery such as septoplasty or turbinotomy, and at last vidian neurectomy if the patient agrees to be operated on after understanding the side effects.

Laser vidian neurectomy

Laser vidian neurectomy appears to offer the technical advantages of a less traumatic, more precisely controlled method of operating in an anatomical area which creates, by its location, technical difficulties in accessibility. Results indicate that postoperative patient comfort is greater, affording the opportunity to perform surgery on an outpatient basis. Results of laser vidian neurectomy are no different than those using conventional techniques.

Role of the vidian nerve in nasal allergy

Clinical studies were performed to evaluate the role of the vidian nerve at onset of symptoms in nasal allergy. A localized area of one side of the nasal cavity was stimulated with known allergen and 0.1% histamine chloride in patients with perennial nasal allergy. The effect of unilateral vidian neurectomy and sensory anesthesia on glandular and vascular response was evaluated. With localized nasal stimulation, hyperrhinorrhea was seen in both sides of the nasal cavity before vidian neurectomy. Unilateral vidian neurectomy blocked hyperrhinorrhea only in that nasal cavity in which the nerve was sectioned. However, hyperrhinorrhea from the contralateral side, with an intact vidian nerve, was blocked with sensory anesthesia of the opposite side of the nasal cavity where the stimulation was applied. Nasal hypersecretion in allergic rhinitis was assumed to be mostly due to stimulation of sensory receptors by a chemical mediator and reflexive stimulation of the nasal glands. Vidian neurectomy, however, did not have any apparent influence on the swelling of the nasal mucosa caused by localized stimulation of allergen and histamine.

Vidian neurectomy: neuroanatomical considerations and a report on a new surgical approach

If conventional treatment fails, vidian neurectomy is a viable alternative for therapy of chronic rhinitis with recurrent polyposis of the nose and sinuses. From a neuroanatomical point of view beneficial and adverse effects of this surgical procedure are discussed. According to our own investigations and experiences, vidian neurectomy should be performed together with clearing out of the sinuses in every case. Beginning with this precondition a new surgical approach was developed: the vidian nerve is detected through a transethmoidal route in the pterygoid canal at the bottom of the sphenoid sinus and dissected using the operation microscope.