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Introduction: Neurotrophic ulceration (NTU) in the trigeminal nerve sensitive area is rare. It may be caused by a lesion anywhere on the trigeminal nerve's trajectory. The diagnosis is usually clinical, but other diagnoses, particularly neoplastic, must be ruled out first. The physiopathology and treatment of NTU remain controversial. We report a severe case of NTU and describe the main features of this poorly documented disease., Observation: A 67-year-old female patient consulted in the dermatology department for a progressive ulceration of the nose ala and the right upper lip, having developed over the two previous years. She had undergone two thermocoagulations of the right Gasserian ganglion for facial neuralgia 3 years before. The diagnosis of NTU, initially ruled out because of biopsies suggesting verrucous carcinoma, was finally retained because of the clinical presentation and anamnesis. Treatment consisted in surgical excision and primary reconstruction using a forehead flap. The diagnosis was confirmed after histopathological examination of the surgical specimen. A recurrence was noted 2 years postoperatively, then the patient was lost to follow-up., Discussion: The physiopathology of NTUs is badly documented. The cutaneous ulcerations look like facial neoplasms but the clinical findings (unilateral and paranasal location; lesion of the trigeminal nerve; local trauma; psychological instability) suggest neurotrophic ulceration. The histopathological examination, sometimes difficult, reveals non-specific chronic inflammatory ulceration. There is no consensus on treatment. The psychological profile may be a risk factor for recurrences and must be taken into account., (Copyright © 2011. Published by Elsevier Masson SAS.)

The authors present a retrospective study of 121 patients treated with balloon compression of the rootlets behind the Gasser ganglion from 1995 to 2007. The inclusion criteria were drug-resistant idiopathic trigeminal neuralgia. The authors described the surgical technique and compared their results with results from the literature. The following parameters were compared: technical success, pain relief and recurrence, and complications. Balloon compression is considered in the literature to be a safer procedure than other percutaneous surgeries, especially for postoperative sensitive disorders. The best indications seem to be trigeminal neuralgia in older patients or pain due to multiple sclerosis and neuralgia involving the V1 territory. These conclusions should be confirmed by larger series, a longer follow-up (> 5 years) and statistically better analysis.

The percutaneous Hartel transoval route goes through an inverted pyramid, with an inferior summit and a superior base that includes three compartments. The danger of the inferior compartment is the parotid duct. The middle compartment contains many branches of the mandibular nerve. The superior compartment is crossed by the internal maxillary artery and its branches, as well as the auditory tube. The base of the pyramid presents not only the foramen ovale, but also the foramen lacerum, where the trocar may injure the internal carotid, and the foramen jugulare, where the trocar may meet the internal jugular vein and nerves of the pars nervosa (IX, X, XI). The trigeminal cave contains, within the trigeminal cistern, the trigeminal ganglion, extended backward by the triangular plexus (the target for thermocoagulation). These structures are undercrossed by the masticatory motor branch of the trigeminal nerve.

The authors report their experience of the treatment of essential trigeminal neuralgia by percutaneous thermocoagulation of the Gasserian ganglion (400 patients). This method has always been performed on anesthetized patients, using an ultra short acting barbiturate: methohexital. Most often, two or three successive coagulations are needed to obtain the desired analgesia. No complications have resulted, although 30 p. cent of our patients were over 70 years old.

Voltage and current within Gasserian ganglion have been measured during a therapeutical high frequency coagulation of the Gasserian ganglion in 25 consecutive cases. From these values, the impedance (Ohm), the work (Watt) and the total energy (Joule) necessary to obtain an analgesia without anesthesia have been calculated. The study has shown that the temperature and the time of coagulation in correlation with the length of the non isolated tip of the electrode are actually the only constancy in the control of the therapeutical lesions.

The results of thermo-coagulation have been evaluated in a series of 50 patients followed up from two to six years (average three years). Neuralgia disappeared in nearly 80 p. 100 of the cases (however this was obtained with a second operation in nine cases). The frequency of recurrences increase with time: 20 p. 100 during the first two years reaching 40 p. 100 after three years. They were more likely to occur if the post-operative sensory deficit is moderate. Complications directly related to the surgical technique were rare: some faded away relatively quickly (oculo-motor palsies less than 1 p. 100, masseter weakness 20 p. 100 in the first weeks). The only residual problems were related to sensory deficits: in general they were limited to a small cutaneous area and total anesthesia was never been observed. Although paresthesias were noted in 12 p. 100 of the cases, these usually were not really troublesome. Our conclusion, therefore, is that differential thermocoagulation appears to be the best surgical treatment for trigeminal neuralgia.

The authors report the late results of thermocoagulation of the gasserian ganglion in 939 patients operated by 3 different neurosurgical teams, (Bologna, Bordeaux, Marseille). It has been assessed that the results are comparable among the 3 teams and that percutaneous selective thermocoagulation represents a simple and low-risk technique with a high rate of efficacity.