Overview

Several disorders that cause facial pain can be successfully treated by neurosurgical procedures. It is important to accurately diagnose the disorder and identify the best treatment for each disorder. In the absence of randomized prospective studies, standardized methods of reporting, and standardized outcome criteria, it is difficult to compare the results of various surgical procedures and the different reported series of the same surgical procedure. Nevertheless, several important observations emerge from reviews of the literature and personal experience.

General Observations on Facial Pain

• Accurate diagnosis is required.
• The diagnosis of typical Trigeminal Neuralgia (TGN) is seldom difficult.
• In general, the length of the list of the patients symptoms is directly proportional to the likelihood of treatment failure.
• Medical treatment should be explored before surgery is contemplated.
• There is no successful surgical procedure for treatment of atypical facial pain.
• It is more difficult to treat neuropathic than neuralgic pain.
• Patients with dysesthetic pain seldom respond to ablative surgery.
• There is no single superior treatment for facial pain. The treatment should be individualized. Patients should have access to a broad spectrum of treatment options.
• The results of surgical treatment diminish as facial pain becomes more chronic.

Results for Vagoglossopharyngeal Neuralgia

Current neurosurgical procedures for the treatment of vagoglossopharyngeal neuralgia include PSR rhizotomy, open intracranial rhizotomy, MVD, and recently PSR trigeminal nucleotomy-tractotomy. In recommending treatment, one must consider the following observations: 

Open intracranial rhizotomy has the highest rate of long-term pain relief
After open rhizotomy of the glossopharyngeal and upper vagal rootlets, long-term pain relief is consistently achieved in more than 90% of patients (38,39). MVD has inconsistently achieved high rates of pain relief. Some surgeons reported pain relief in more than 90% of patients after MVD (40,41), Resnick et al. reported a 76% pain relief in patients followed for more than 2 years (42). 

PSR rhizotomy carries the highest risk of postoperative dysphagia, vocal cord paralysis, and irritative cough
The authors have had difficulty achieving precise controlled coagulation of the glossopharyngeal and vagal nerves. Many series have reported dysphagia and vocal cord paralysis after PSR rhizotomy (38). The authors restrict the use of PSR rhizotomy to patients with glossopharyngeal neuralgia from cancer who already have developed vocal cord paralysis and swallowing difficulty. 

Open rhizotomy has been associated with 10-20% risk of temporary swallowing problems (38). Many authors have decreased this risk by restricting vagal rhizotomy to the upper two or upper third of the vagal rootlets and preserving the upper large-diameter vagal rootlets (38). The authors have not encountered cases of postoperative permanent dysphagia or vocal cord paralysis after they used intraoperative monitoring of the false vocal cord to differentiate motor from sensory vagal rootlets (43). 

MVD was introduced to minimize the risks associated with section of the upper vagal rootlets; however, dysphagia and vocal cord paralysis can develop from excessive manipulation of the lower cranial nerves. In the series of Resnick et al., 10% of patients developed transient paresis of the cranial nerves IX and X and 2% developed permanent moderate swallowing difficulty (42). 

Perioperative care
Patients with glossopharyngeal neuralgia may develop hemodynamic instability during intubation, manipulation of the lower cranial nerves, and postoperatively secondary to hypersensitivity to the vagus nucleus, ephaptic transmission between cranial nerves IX and X or nuclei, and hypersensitivity of the carotid sinus reflex. Before laryngeal intubation, topical anesthesia to the oropharynx and intravenous atropine should be administered. Intraoperatively, the surgeon should avoid excessive manipulation of the lower cranial nerves to decrease risks of severe fluctuations of blood pressure and heart rate. Atropine should be administered prior to section of the vagal rootlets. Strict postoperative control of blood pressure is required to avoid hypertensive crisis. These risks should be taken seriously. In the series of Resnick et al. of MVD, the mortality rate from hemodynamic instability was 5% (42). 

Open rhizotomy is recommended for patients with vagoglossopharyngeal syncope
Ten percent of patients with vagoglossopharyngeal neuralgia develop sudden excessive vagal outflow during an attack resulting in bradycardia, heart arrhythmias, hypotension, syncope, seizure, or cardiac arrest, known as vagoglossopharyngeal syncope. Bradyarrythmia can be transiently blocked by atropine, while hypotension usually responds to local injection of lidocaine near the carotid bifurcation (38). Vagoglossopharyngeal syncope can be successfully treated with carbamazepine and with open rhizotomy (38). Data are insufficient to support the use of MVD or other surgical procedures for this disorder. 

Open rhizotomy is contraindicated in bilateral glossopharyngeal neuralgia. In the rare event of bilateral glossopharyngeal neuralgia, open rhizotomy carries a high risk of swallowing problems from sectioning both glossopharyngeal nerves (38). In bilateral glossopharyngeal neuralgia, MVD is likely the treatment of choice. 

Conclusion
Open rhizotomy seems to have the highest rate of long-term pain relief. Risks of postoperative dysphagia and vocal cord paralysis are minimized by using intraoperative vagal monitoring. MVD has a low risk of permanent dysphagia and vocal cord paralysis and a lower rate of long-term pain relief. Open rhizotomy is the treatment of choice for patients who experience vagoglossopharyngeal syncope. MVD is the treatment of choice for patients who develop bilateral glossopharyngeal syncope. PSR rhizotomy should be restricted to patients with pain of cancer who already have swallowing problems and vocal cord paralysis. Percutaneous trigeminal nucleotomy-tractotomy requires further evaluation before recommending it as a treatment option (44).

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Sources

Through the Trigeminal Neuralgia Association (TNA), local support groups are available. The support group provides an opportunity for patients and their families to share experiences, receive support, and learn about advances in treatments, pain control, and medications. Additional information is available on the web at www.tna-support.org or facial-neuralgia.org

If you would like information about the Greater Cincinnati Trigeminal Neuralgia Support Group, please call the Mayfield Clinic at (513)569-5290. For support outside Greater Cincinnati, please contact the Trigeminal Neuralgia Association at 800-923-3608. 

The following journal articles and books formed the basis of our observations along with our own personal experience. Bibliography listing.

updated: 6.2004
originally published > Tew JM, Taha JM: Therapeutic Decisions in Facial Pain. Clinical Neurosurgery 46:410-431, 2000