TRIGEMINAL ROOT AND GANGLION INJECTIONS USING PHENOL IN GLYCERINE FOR THE RELIEF OF TRIGEMINAL NEURALGIA

Infratemporal Fossa Vascular Anatomy Pertinent to Percutaneous Access to the Foramen Ovale for Treatment of Trigeminal Neuralgia: A Comparison of Cadaveric Dissection and Computed Tomography Analysis

BACKGROUND

Trigeminal neuralgia may be treated via percutaneous access to the foramen ovale (FO). Vascular complications associated with the needle trajectory can result in serious morbidity and mortality. This study aimed to correlate the vascular relationships of the FO at the skull base via cadaveric dissections and computed tomography (CT).

METHODS

Two fresh cadaver heads were injected with red and blue latex to delineate arteries and veins. Neck and infratemporal fossa dissections were carried out to delineate the vascular relationships of the FO. High-resolution head CT images of adult patients undergoing neurosurgical evaluations or procedures were analyzed for distances and sizes of skull base foramina in the infratemporal fossa.

RESULTS

Three infratemporal fossa dissections (2 cadaveric specimens) were performed. Mean distance of FO to internal carotid artery was 2.4 ± 0.12 cm, and mean distance of FO to middle meningeal artery was 0.8 ± 0.16 cm. Head CT images of 52 patients (104 sides) with 1-mm axial slice thickness were analyzed. Area of the FO was 31.1 ± 9.6 mm². Distance of FO to internal carotid artery was 1.70 ± 0.31 cm, and distance of FO to middle meningeal artery was 0.73 ± 0.61 cm.

CONCLUSIONS

Cadaveric delineation of vascular structures in the infratemporal fossa correlates with head CT imaging and may be used to accurately plan percutaneous access to the FO. Inadvertent puncture of the extracranial internal carotid artery is nearly impossible with good technique. The most likely source of percutaneous vascular injury is the middle meningeal artery and distal branches of the maxillary artery.

Trigeminal Neuralgia: Current Approaches and Emerging Interventions

Trigeminal neuralgia (TN) has been described in the literature as one of the most debilitating presentations of orofacial pain. This review summarizes over 150 years of collective clinical experience in the medical and surgical treatment of TN. Fundamentally, TN remains a clinical diagnosis that must be distinguished from other types of trigeminal neuropathic pain and/or facial pain associated with other neuralgias or headache syndromes. What is increasingly clear is that there is no catch-all medical or surgical intervention that is effective for all patients with trigeminal neuralgia, likely reflective of the fact that TN is likely a heterogenous group of disorders that jointly manifests in facial pain. The first-line treatment for TN remains anticonvulsant medical therapy. Patients who fail this have a range of surgical options available to them. In general, microvascular decompression is a safe and effective procedure with immediate and durable outcomes. Patients who are unable to tolerate general anesthesia or whose medical comorbidities preclude a suboccipital craniectomy may benefit from percutaneous methodologies including glycerol or radiofrequency ablation, or both. For patients with bleeding diathesis due to blood thinning medications who are ineligible for invasive procedures, or for those who are unwilling to undergo open surgical procedures, radiosurgery may be an excellent option-provided the patient understands that maximum pain relief will take on the order of months to achieve. Finally, peripheral neurectomies continue to provide an inexpensive and resource-sparing alternative to pain relief for patients in locations with limited economic and medical resources. Ultimately, elucidation of the molecular mechanisms underlying trigeminal neuralgia will pave the way for novel, more effective and less invasive therapies.

Historical aspects of the problem of treatment of trigeminal neuralgia and the role of neurosurgical methods in its solution (literature review)

The trigeminal nerve is a mixed fifth cranial nerve, consisting of motor and sensory components. The sensitive component receives somesthetic information from the skin and mucous membranes of the face into the central nervous system, and the motor component is responsible for the innervation of chewing muscles. One of the manifestations of the pathology of the trigeminal nerve is pain syndrome. Trigeminal neuralgia occupies the main place among neurogenic pain syndrome in the face, is characterized by а severe course and the absence of sufficiently effective methods of treatment. According to the World Health Organization (WHO), the prevalence of trigeminal neuralgia in different countries is 2–5 cases per 100 thousand people per year. Trigeminal neuralgia is classified into 3 etiologic categories. Idiopathic trigeminal neuralgia occurs without apparent cause. Classical trigeminal neuralgia is caused by vascular compression of the trigeminal nerve root. Secondary trigeminal neuralgia is the consequence of a major neurologic disease, e. g., a tumor of the cеrеbеllоpоntine angle or multiple sclerosis. Today, there are many different options for the surgical treatment of trigeminal neuralgia. microvascular decompression of the root, radiosurgical destruction of the Gasser’s node, radiofrequency destruction, glycerol rhizotomy, balloon microcompression are considered the main effective and proven surgical methods for treating trigeminal neuralgia. But the questions of diagnosing the cause of the disease and choosing an adequate surgical method for treating therapeutically resistant trigeminal neuralgia for a particular patient remain open. The development of surgical methods begins from ancient times to the present day. The main stages in the development of neurosurgical treatment methods are presented. The following surgical techniques are described: open method – microvascular decompression, and closed percutaneous destructive methods – radiofrequency destruction, glycerol rhizotomy, balloon compression, radiosurgery, cryodestruction, laser destruction, botulinum toxin injections.

Gamma Knife Radiosurgery in Recurrent Trigeminal Neuralgia after Other Procedures

Objectives Trigeminal neuralgia (TN) is undurable paroxysmal pain in the distribution of the fifth cranial nerve. Invasive treatment modalities for TN include microvascular decompression (MVD) and percutaneous procedures, such as, radiofrequency rhizotomy (RFR). Gamma Knife radiosurgery (GKRS) is a considerable option for patients with pain recurrence after an initial procedure. This study was undertaken to analyze the effects of gamma knife radiosurgery in recurrent TN after other procedures. Methods Eleven recurrent TN patients after other procedures underwent GKRS in our hospital from September 2004 to August 2016. Seven patients had previously undergone MVD alone, two underwent MVD with partial sensory rhizotomy (PSR), and two underwent RFR. Mean patient age was 60.5 years. We retrospectively analyzed patient's characteristics, clinical results, sites, and divisions of pain. Outcomes were evaluated using the Visual Analog Scales (VAS) score. Results Right sides were more prevalent than left sides (7:4). The most common distribution of pain was V1 + V2 division (n = 5) following V2 + V3 (n = 3), V2 (n = 2), and V1 + V2 + V3 (n = 1) division. Median GKRS dose was 80 Gy and the mean interval between the prior treatment and GKRS was 74.45 months. The final outcomes of subsequent GKRS were satisfactory in most cases, and at 12 months postoperatively ten patients (90.0%) had a VAS score of ≤ 3. Conclusions In this study, the clinical result of GKRS was satisfactory. Invasive procedures, such as, MVD, RFR are initially effective in TN patients, but GKRS provides a safe and satisfactory treatment modality for those who recurred after prior invasive treatments.

Surgical treatment of cranial neuralgias

The most common types of cranial neuralgias amenable to surgical therapeutic options are trigeminal neuralgia and glossopharyngeal neuralgia, the former having an approximate incidence of 5/100000 cases per year and the latter of 0.05/100000 cases per year. Surgical therapy of these pathological conditions encompasses several strategies, going from ablative procedures to neurovascular decompression, to radiosurgery. The choice of the most appropriate surgical option (which must be taken into account when all conservative treatments have proven to be unsuccessful) has to take into account many factors, the most important ones being neuroradiological evidence of a neurovascular conflict, severity of symptoms, the age and clinical history of the patient, and the patient's overall medical condition. In this chapter we report our experience with the treatment of trigeminal and glossopharyngeal neuralgia, describing the surgical procedures performed and reviewing the most recent aspects on this subject in the past literature.

Percutaneous retrogasserian glycerol rhizotomy for trigeminal neuralgia: technique and expectations

Object

In the management of trigeminal neuralgia (TN), physicians seek rapid and long-lasting pain relief, together with preservation of trigeminal nerve function. Percutaneous retrogasserian glycerol rhizotomy (PRGR) offers distinct advantages over other available procedures. The aim of this report was to provide details of the PRGR procedure and its expected outcome.

Methods

The authors reviewed their experience with PRGR in 1174 patients to evaluate the procedural technique, results, and complications. Although it is clear that TN is not a static disorder but one characterized by remissions and recurrences, long-lasting pain relief was noted in 77% of patients, with 55% discontinuing all medications and 22% requiring some drug usage.

Conclusions

The authors discuss the role of PRGR in their practice, along with other procedures such as microvascular decompression and gamma knife surgery, for idiopathic or multiple sclerosis–related TN. They conclude that PRGR had distinct advantages over other procedures, which include eliminating the need for intraoperative confirmatory sensory testing, and a lower risk of facial sensory loss.

Improved visualization of the foramen ovale for percutaneous approaches to the gasserian ganglion. Technical note

Percutaneous procedures for treating trigeminal neuralgia involve the penetration of foramen ovale using cutaneous landmarks and radiological guidance. The placement of radiopaque markers over the commonly used "zygomatic points" in front of the ears provides landmarks on intraoperative radiological studies that facilitate localization of the foramen ovale. Speed and safety of percutaneous trigeminal procedures should be enhanced. There is no increase in radiation exposure over that in other commonly used approaches.

Percutaneous retrogasserian glycerol rhizotomy. Predictors of success and failure in treatment of trigeminal neuralgia

Eighty-five medically intractable trigeminal neuralgia patients treated by percutaneous retrogasserian glycerol rhizotomy (PRGR) were followed for 6 to 54 months. The median time to recurrence of symptoms refractory to medical therapy and requiring further intervention was 3 years (by Kaplan-Meier survival analysis). The median time to recurrence of symptoms requiring some form of medical treatment was 2 years. Following repeat PRGR for recurrent symptoms, the median time to recurrence was 1 year. Univariate log rank statistics and multivariate Cox proportional hazards modeling revealed significant associations between favorable outcome and female sex, absence of atypical features or associated cluster headache symptoms, success of prior carbamazepine therapy, duration of symptoms, and cerebrospinal fluid return during the procedure. A scoring system using prognostic factors has been developed based upon these findings. Assessment of published studies of PRGR and of other treatments for trigeminal neuralgia is made difficult by the variety of outcome measures employed and variable follow-up intervals. The present study attempts to address these issues by definition of endpoints, statistical analysis of the data, and identification of important prognostic factors in a manner useful to the clinician.

Current concepts concerning the etiology and treatment of trigeminal neuralgia

Trigeminal neuralgia (tic douloureux) was first identified over three hundred years ago. Only recently have the causes of the disorder begun to be recognized and understood. The first attempts at treatment involved the neurotomy of peripheral branches of the trigeminal nerve. This procedure, along with neurectomy, ganglionectomy, rhizotomy, tractotomy, and injections of toxic substances into the ganglion and nerve branches were the main treatment modalities in years past. Although they exhibited marked success, they are fraught with complications, such as relapse, loss of facial sensation and motor control, infection, deafferentation pain, and a fairly high rate of mortality from the procedure. The current treatment modalities that result in a predictable success with minimal risk are microvascular decompression, percutaneous retrogasserian thermal rhizotomy, and percutaneous retrogasserian glycerol rhizotomy. Other procedures, such as balloon compression of the gasserian ganglion, cryotherapy, acupuncture, and drug therapy, are also being used with marked promise.

Extravesical subtrigonal injection of 50 per cent ethanol for detrusor instability

Urinary incontinence with detrusor instability often is refractory to pharmacological therapy as well as other conservative modalities. We report the results obtained from 10 patients with detrusor incontinence who underwent extravesical subtrigonal injection of 50 per cent ethanol. Postoperatively, 9 of the 10 patients had conversion to detrusor stability and 6 had an acontractile bladder. Of the 10 patients 9 had an excellent result for at least 10 months postoperatively with 1 patient requiring 2 additional treatments to convert to detrusor stability. Complications included fistula formation in 3 patients, requiring primary closure in 2 and ileal diversion in 1. Of the 10 patients 7 remain dry or vastly improved at a mean of 24 months of followup.

Controlled thermocoagulation in trigeminal neuralgia

Results of 280 radiofrequency lesions on 229 patients with trigeminal neuralgia are presented with three months to eight years (average 3.8 years) follow up. The patients were aged from 18-91 years. There was a high overall success rate of 94%. The complication rate has been low, with sensory paraesthesiae the commonest (15%) and cranial nerve palsies very rare (2.4%) compared to other reported series.

High resolution CT of Meckel's cave

High resolution CT of the parasellar region was carried out in 50 patients studied for suspected pituitary microadenoma, but who showed normal pituitary gland or microadenoma on CT. This control group of patients all showed an ellipsoid low-density area in the posterior parasellar region. Knowledge of the gross anatomy and correlation with metrizamide cisternography suggest that the low density region represents Meckel's cave, rather than just the trigeminal ganglion alone. Though there is considerable variation in the size of Meckel's cave in different patients as well as the two sides of the same patient, the rather constant ellipsoid configuration of the cave in normal subjects will aid in diagnosing small pathological lesions, thereby obviating more invasive cisternography via the transovale or lumbar route. Patients with "idiopathic" tic douloureux do not show a Meckel's cave significantly different from the control group.

Anaesthetic considerations in percutaneous radiofrequency coagulation of the Gasserian ganglion

This study determined the cardiovascular effects of percutaneous radiofrequency coagulation of the Gasserian ganglion, performed under neuroleptanalgesia and intermittent ultrashort-acting barbiturate anaesthesia. Twelve ASA physical status class II patients were studied. Highly significant increases in mean heart rate and arterial blood pressure followed the insertion of the cannula electrode into the Gasserian ganglion (p less than 0.001). In six randomly assigned patients severe tachycardia and hypertension also accompanied the progress of the thermal lesion (p less than 0.0001). Three patients developed premature ventricular contractions, and two developed significant ST segment depression. Intravenous nitroglycerin, used during current generation, successfully controlled the hypertensive response in the other six patients. In percutaneous thermocoagulation of the Gasserian ganglion the patient's co-operation is essential. In addition to providing suitable operating conditions for both surgeons and patient, we should also be able to maintain normal and stable cardiovascular haemodynamics. Intravenous nitroglycerin used as an adjunct to light general anaesthesia safely maintained intraoperative normotension. It is also suggested that patients with coronary artery disease be adequately monitored and protected during the procedure.

The place of ganglion or root alcohol injection in trigeminal neuralgia

Of 157 patients with trigeminal neuralgia, referred for neurosurgery, 81 underwent 85 ganglion or root injections. The results, which are analysed with regard to pain relief and sensory loss, compare favourably with results from the literature of other forms of surgery, particularly open temporal root section.

Controlled thermocoagulation of trigeminal ganglion and rootlets for differential destruction of pain fibers. 1. Trigeminal neuralgia

✓ The authors report their experience in the treatment of trigeminal neuralgia with controlled increments of radiofrequency heating from an electrode placed in the Gasserian ganglion or its posterior rootlets. Touch is preserved in some or all of a trigeminal zone rendered analgesic. The electrode tip is introduced through the foramen ovale and placed among the desired rootlets with the help of a combination of radiographs and the conscious patient's response to electrical stimulation with a square wave signal and gentle electrical heating. The degree of heat is measured by a thermister at the electrode tip. The patient's cooperation is maintained by the use of the neurolept anesthetic Innovar and the production of brief unconsciousness for the painful parts of the operation by methohexital (Brevital). Of 274 patients with facial pain so treated, 214 had trigeminal neuralgia; 91% of the latter group experienced relief of pain and 125 followed for 2½ to 6 years had a recurrence rate of 22%. In a total of 353 procedures, there has been no mortality and no neurological morbidity outside the trigeminal nerve. Only six of the patients with trigeminal neuralgia have complained significantly of postoperative paresthesias. The most serious undesired result has been the production of an anesthetic cornea in 28 patients, one of whom lost the sight of one eye due to corneal scarring. Correlating findings in our patients with those in studies by other authors, we conclude that the preservation of some touch is due to resistance to heating by the heavily myelinated A-beta fibers.