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Purpose: This work was conducted to determine the effects of unilateral trigeminal ganglion ablation on lacrimal gland structure and secretory activity., Methods: Adult male New Zealand rabbits underwent unilateral thermocoagulation of the ophthalmic division of the trigeminal ganglion. Sensory denervation was affirmed by anatomic inspection of the lesion and transmission electron microscopy (TEM) of the lacrimal gland innervation. Eight to 10 days after the procedure, the intraorbital lacrimal glands were removed from both sides. To compare the physiologic competence of the intact and denervated glands, freshly isolated gland fragments from the paired intact and denervated glands were stimulated with carbachol (100 microM), isoproterenol (10 microM), phorbol-12,13-dibutyrate (PDBu, 10 microM), forskolin (40 microM), or vehicle. Total secreted protein was measured at 30 or 60 min after the establishment of baseline values. Intact and denervated glands also were examined by light and TEM, and the morphologic appearance of the acinar structures as well as the appearance of nerves innervating the gland after denervation were assessed. Similar experiments were conducted with animals that underwent unilateral superior cervical ganglionectomy., Results: Tissues from sensory denervated glands released significantly more protein than did tissues from innervated glands in response to in vitro stimulation by carbachol or isoproterenol but not in response to PDBu or forskolin. Microscopy showed that the acinar cells that had undergone sensory denervation showed a massive accumulation of secretory granules. The secretory granules filled the entire cytoplasmic space and displaced the ellipsoidal nuclei to the extreme periphery. Examination of segments of nerves revealed numerous unmyelinated axons, a few small-diameter myelinated axons, and a large amount of nerve degeneration after sensory denervation. In contrast to the effects of sensory denervation, sympathetic denervation did not alter either the acinar appearance or secretory responsiveness of the gland., Conclusion: Loss of the considerable sensory innervation from the trigeminal ganglion has pronounced effects on the pharmacologic responsiveness and the structure of the lacrimal gland. The effects of sensory innervation on the gland may be mediated through two possible pathways: direct input to the gland or control of the preganglionic parasympathetic pathway.

A profusion of surgical approaches to gain access to the anterior and middle cranial fossa and skull base have been described. An attempt has been made to simplify the position by suggesting a classification of surgical approaches and to describe a standard approach (of at most 4 defined osteotomies, or at least 2) to give a craniofacial approach to the anterior and middle cranial fossae, the infratemporal fossa, the orbit and the superior nasal cavity. The full extent of the osteotomies have been likened to an ancient Corinthian face mask, or to the stylized face-mask worn by the comic book hero, Batman.

The cervico-ocular reflex (COR) was studied alone or in combination with the vestibulo-ocular reflex (VOR) in the rabbit. Step stimulations of the body with respect to the fixed head induced small slow compensatory responses followed by large compensatory quick phases (QP). These responses remained aligned with the horizon at different head pitch angles. The QP reorientation in space was due to the gravity influence on the otolithic receptors. The vestibular induced QPs exhibit a similar pattern. Because of this reorientation, the reduction of the amplitude of the vestibular induced QPs, due to the addition of the COR, was maintained even at different static head positions. The electrolytic lesion of the ophthalmic branch of the trigeminal nerve deeply affected the space orientation of the COR. In particular, the cervically induced compensatory QPs of the eye ipsilateral to the lesion showed a remarkable variability of their trajectories and they lost space reorientation. These findings suggest that the coordinate system controlling the QPs is influenced by signals originating from both head position in space and eye position in the orbit.

Objective and Importance: Intracranial hemangioendotheliomas are rare lesions, especially in the pediatric age group. Recognizing hemangioendotheliomas as a differential in intracranial tumors of vascular origin is important; complete excision results in a cure, and medical therapy for those lesions that are not resectable produces long-term survival., Clinical Presentation: We report two patients, a 7-year-old female patient with a lesion in the right gasserian ganglion and a 3-month-old male patient with a cervicomedullary junction tumor., Intervention: The 7-year-old underwent a gross total removal with no recurrence. The 3-month-old underwent a partial resection followed by treatment with interferon alpha-2a, with a decrease in the size of the residual tumor. Both patients have been followed for more than 4 years without a recurrence or progression of the tumor., Conclusion: Hemangioendotheliomas are fairly indolent tumors and may be treated with complete surgical resection, resulting in a cure. In cases in which complete tumor removal is not possible, adjunctive therapy with interferon alpha-2a may control residual tumor growth.

During surgical exposure of the trigeminal root for the treatment of trigeminal neuralgia, biopsy specimens of the nerve root were taken in 12 consecutive patients. The biopsies were taken from areas as close as possible to the site of vascular compression, when present. The tissue was prepared for electron-microscopic evaluation. Except for 1 case, massive disruption of tissue ultrastructure was observed. The major findings included zones of de- and dysmyelination, juxtaposition of denuded axons, apparent axon loss and degeneration, and collagen deposition. Adjacent areas of normal root structure were present in most specimens. The ultrastructural changes observed in the biopsy samples demonstrate important pathology within the trigeminal root. Dysmyelination and the proximity of denuded axons in close apposition to each other support neurophysiological theories of pain production including ectopic electrogenesis, ephaptic contacts, and crossed after-discharge. The findings in this study demonstrate a pathophysiological basis for the syndrome of trigeminal neuralgia.

Neuralgia of the trigeminus (NT) is the most common of cranial nerve neuralgias. Its diagnosis is entirely clinical and its most common form of presentation is well understood. Questions of differential diagnosis can emerge with certain entities such as atypical trigeminal neuralgia, short-duration unilateral neuralgiform cephalea of the trigeminus (SUNCT) arising from injection to the conjunctival, lacrimal or other glands, cluster headache, chronic paroxymal hemicrania, pain arising in the teeth and myofacial pain syndrome. The three main causative factors of NT are compression of the nerve root by an artery in the prepontine space, thereby creating an area of demyelinization, compression of the nerve by a tumor, and multiple sclerosis. The first is the most common of the three. NT can be classified as essential in 10 to 30% of patients. Recent advances in magnetic resonance (MR), and its advantages over other imaging systems, have made MR the diagnostic method of choice. The first treatment is medical and the basic drugs involved can be considered classic. Other therapies have been suggested in recent years, however, and should probably be studied further. Two substances stand out among those proposed: tocainide, an antiarrhythmic drug, and pimozide, an antipsychotic. Surgical treatment of NT can address either the cause (tumor or vascular compression) or symptoms, the latter being indicated when medical treatment fails. Surgery can be performed on peripheral nerves, on the gasserian ganglion and on the posterior fossa. The indications, outcomes and possible complications are quite different for each approach, making choice controversial.

We analyzed 417 patients with trigeminal neuralgia who underwent microvascular decompression (MVD; n = 146) or percutaneous procedures, i.e. radiofrequency rhizotomy (RFR; n = 235) and glycerol rhizotomy (GR; n = 36) between March 1973 and December 1996. MVD and RFR showed the highest rates of initial pain relief (MVD 96.5%; RFR 92.3%; GR 82.8%). RFR and GR had 5.1 and 3.3% rates of facial dysesthesia, respectively, and MVD had the lowest rate (0.3%). Among 9 cases (8.6%) with recurrences after MVD, 8 cases underwent RFR and all of them obtained good long-term results (7.2 years on average). We concluded that MVD is the treatment of choice for tolerant younger patients and should be recommended for patients who desire no sensory deficit. We also determined that radiofrequency rhizotomy is the procedure of choice for patients in whom MVD failed.

Despite the establishment of the vasculoneural compression as a frequent cause of trigeminal neuralgia, minimally invasive surgical techniques to treat medically refractory trigeminal neuralgia are needed in order to minimize the risks associated with craniotomy. Percutaneous retro gasserian glycerol rhizotomy (PRGR) is one of the alternative surgical treatments to microvascular decompression. Technical simplicity, less chance of trigeminal sensory loss, no need of intraoperative sensory testing, and no attempted deliberate destruction of the trigeminal nerve are advantages over other percutaneous trigeminal operations.

From January 1, 1986, to June 30, 1996, 240 patients were operated on for trigeminal neuralgia: 182 patients were treated by thermocoagulation of the gasserian ganglion after Sweet and 58 patients by decompression of the trigeminal nerve after Janetta. In the thermocoagulation group, followed up for 6 months to 10 years 95.2% of the cases showed freedom from pain, in the Janetta operation group, followed up for 6 months to 6 years 98.5% showed freedom from pain. Thermocoagulation is the preferred therapy, especially in older patients in whom general anesthesia is risky, while the Janetta operation is the therapy of choice in younger patients.

The aim of the present study was to evaluate the long-term results of a series of 200 patients operated on by percutaneous compression of the gasserian ganglion (PCGG) according to Mullan and Lichtor's technique. The balloon was inflated for 6 min with 0.7 cm3 of iopamiro. We report excellent and satisfactory results in 62.5% of the cases and recurrence in 32.5% with a mean follow-up of 51 months. Severe sensory complications were rare (3%), whereas hearing disturbances were more frequent (11%). One unfortunate postoperative death was reported. With acceptable morbidity and in spite of this death, PCGG is an effective method which can easily be repeated in the treatment of trigeminal neuralgia.

We assessed thresholds for sensation of temperature and pressure and temporal summation of pain in the trigger area on the painful side and the contralateral nonpainful side in patients with trigeminal neuralgia previously treated with percutaneous retrogasserian glycerol rhizotomy (PRGR). Temperature and tactile thresholds were significantly increased on the painful side in both pain-free patients and patients with paroxysmal pain, but sensory loss was not more severe in patients with paroxysmal pain, except for increased warm thresholds. Abnormal temporal summation of pain (including progressive increase of pain intensity with radiation of pain and aftersensation) was present in the trigger area of patients with paroxysmal pain, but not in pain-free patients. Thus, relief of trigeminal neuralgia after PRGR involves normalization of abnormal temporal summation of pain, whereas sensory loss is less affected.

The lancinating facial pain of trigeminal neuralgia usually responds to medical treatment. However, in some patients, trigeminal neuralgia is refractory to drug therapy. In addition, some patients are unable to tolerate the side effects of medication. In these cases, several safe and effective surgical procedures are available for the treatment of this common facial pain syndrome.

At the end of the 19th and the beginning of the 20th centuries, German surgeons played a large role in the development of neurologic surgery. Many of them, however, have not been fully appreciated by the neurosurgical community until now. Pioneering personalities like F. Krause and F. von Bramann have contributed considerably to the early establishment of standard neurosurgical principles and operative techniques. Alexander Stieda was their successor and kept alive the neurosurgical tradition in Halle until the end of World War II. This middle-sized city in Central Germany, with an old university where Martin Luther once taught, was especially privileged to be one of the places where some of the best-qualified and restless surgeons have practiced neurologic surgery and done work in progress. This paper traces the biographies of the great old masters of German neurosurgery in search of the "Halle connection" to the progress of our field.

The techniques of two experimental surgical operations on the trigeminal nerve are described, namely, excision of the trigeminal ganglion (ganglionectomy) and division of the trigeminal root (rhizotomy), in the cat. These techniques have been developed with the specific aims of achieving the trigeminal lesion and also preserving a satisfactory postoperative quality of life for the animal in order to make it possible to study the long-term effects of trigeminal dennervation. To the best of our knowledge, a detailed description of such a surgical methodology is lacking; reporting of these procedures may facilitate future research on the trigeminal nerve.

The results of Gamma Knife stereotactic radiosurgery in the management of 51 patients who had typical trigeminal neuralgia were evaluated at the University of Pittsburgh. In all cases, a 4-mm isocenter was targeted at the proximal nerve at the root entry zone. The target dose varied from 60 to 90 Gy. Forty-four patients (86%) had undergone prior surgery. The mean follow-up after radiosurgery was 9.6 months (range, 2-29 months). The initial response rate was 86%. At the last follow-up, 19 patients (37%) had excellent control (pain free), 21 (41%) had good control (50-90% relief), and 11 (21%) had failed treatment. No patient developed further sensory loss or deafferentation pain. A maximum radiosurgery dose > or = 70 Gy was associated with a significantly greater chance for complete pain relief. Using magnetic resonance imaging stereotactic targeting, the proximal trigeminal nerve is an appropriate anatomic target for radiosurgery. Gamma Knife radiosurgery is a useful additional surgical approach in the management of medically or surgically refractory trigeminal neuralgia.

Percutaneous rhizotomy of the trigeminal ganglion is an established technique in the management of trigeminal neuralgia. Meningitis has been reported as a complication of radiofrequency rhizotomy. We report two cases in which percutaneous glycerol injection of the trigeminal ganglion was followed by meningitis due to oral streptococci. While initial laboratory features might be considered consistent with meningitis due to Streptococcus pneumoniae, optimal therapy is likely to differ as a consequence of current antimicrobial susceptibility patterns.

Although the primary treatment of chronic cluster headache is medical, surgical treatment is sometimes used. The authors reviewed the charts of seven patients (ages 36 to 68 years) with chronic cluster headache to identify who responded best to percutaneous stereotactic radiofrequency rhizotomy after medical treatment failed. All patients had immediate pain relief after surgery. At follow-up (median 5 years, range 2 to 20 years), two patients remained pain-free 7 and 20 years later (excellent results); three patients had mild pain recurrence that was well controlled on medications (good results) 6 to 12 months after surgery; and two patients had major pain recurrence 4 days and 2 months after surgery (poor results). Six patients had relief of vasomotor symptoms. One patient had transient diplopia and keratitis without permanent sequelae. Both patients with excellent results had preoperative major pain around the eye; both patients with poor results had major pain around the temple, ear, and cheek; and the three patients with good results had pain equally severe in the eye, temple, and cheek. There was no association between patient age or sex, pain duration, preoperative response to lidocaine blockade, or previous surgery with pain relief. No differences occurred in pain relief between patients with dense hypalgesia and patients with analgesia. The authors conclude that (1) some patients with chronic cluster headache treated by percutaneous stereotactic radiofrequency rhizotomy achieve long-term pain relief, and (2) surgery on the trigeminovascular system alone may not cure the condition in patients with major pain around the temple, ear, and cheek.

Twenty-three patients with intractable trigeminal neuralgia were treated by a modified technique of middle fossa extradural decompression of the trigeminal sensory root at the petrous ridge. After exposing the ganglion and the root at the petrous ridge, by an extradural Frazier's approach a thin layer of autogenous fat was interposed between the dura propria and the middle fossa dura anteriorly, and between the petrous ridge and the root posteriorly. The fat layers were used to prevent dural adhesions and to maintain a space between the petrous ridge and the root. The dura propria was preserved intact. All patients obtained immediate relief of pain following surgery. Twenty patients continue to remain pain free. Two patients have mild occasional pains and one has a persistent pain of moderate intensity. One patient developed a dense sensory loss and two had delayed facial weakness which recovered completely within a month. The mechanism of trigeminal neuralgia is discussed on the basis of anatomical, histopathological and electrophysiological findings and the rationale of middle fossa decompression of the root is stressed. This method is short, simple and safe and may serve as an alternative to the more recent methods of treating trigeminal neuralgia.

The blink reflex was prospectively studied in 28 patients with trigeminal neuralgia, prior-to and following percutaneous glycerol rhizotomy to the Gasserian ganglion. Fifteen patients (54%) had varying degrees of sensory loss in the trigeminal nerve distribution already before glycerol injection. Three more patients developed sensory loss following glycerol injection. Thus following glycerol injection 18 patients had graded sensory loss. Pre-injection the blink reflex showed abnormal R1 wave in 57% patients, while direct and consensual R2 waves were abnormal in 43% and 48%, respectively. Post-injection R1 wave was abnormal in 64% patients. Direct R2 waves were abnormal in 33% patients. Thus clinical findings of sensory loss correlated well with pre-and post-injection blink reflex abnormality. Postoperatively R1 and ipsilateral R2 latencies from the side of the injection deteriorated and consensual R2 latency improved, thus, signifying better function on the contralateral side following relief of pain by glycerol rhizotomy.

A modified lateral subtemporal, transpetrous apex and sub-Gasserian ganglion approach was found to be most suitable for clival chordomas. The approach selection was based on the typical anatomical relationship of chordomas in terms of site of origin, pattern of growth and neural and vascular displacements. The approach was suitable to deal with tumour anterior and lateral to the brain stem, the clival part of the tumour and its sub-cavernous sinus extensions. The carotid artery was under control. The approach had the advantage of being simple and relatively quick and of its familiarity to general neurosurgeons. The tumour could be excised radically and extension of anterior, posterior and inferior exposure was possible.

We analyze the results of treatment and the course of disease in 20 patients suffering from chronic cluster headache. Patients were followed for an average of 5 years. Sumatriptan provided the most effective relief of symptoms in those who used that medication. The results of surgical and medical prophylaxes were poor. The disease either remitted or changed to an episodic variety after several months or years in most patients. There is no evidence to suggest that these changes were related to any particular treatment.

Percutaneous compression of the trigeminal ganglion, which is currently being used for the control of trigeminal neuralgia, induces marked intraoperative elevations of the systemic blood pressure and heart rate changes, which may increase the risk of cardiovascular complications. We have analyzed the characteristics of the arterial hypertensive response and the cardiac rhythm changes induced by percutaneous compression of the trigeminal ganglion in 42 consecutive, unselected patients undergoing operations for essential trigeminal neuralgia under three different regimens of anesthesia. The first 22 patients (Group 1) underwent operations under brief general anesthesia without endotracheal intubation. The following 10 patients (Group 2) had general anesthesia with intubation and mechanical ventilation and received larger doses of hypnotic and analgesic agents. Finally, 10 more patients (Group 3), who had general anesthesia with intubation, underwent local anesthetic blockade of Meckel's cave (injection of 1 ml of 1% lidocaine) before ganglion compression. Foramen ovale puncture elicited bradycardia in the majority of the patients of Groups 2 and 3, but only four patients (18%) of Group 1 showed bradycardia. Ganglion compression caused marked tachycardia in all patients of Groups 1 and 2; about one-third of the patients also had extrasystoles. By contrast, patients of Group 3, who had local anesthetic blockade of Meckel's cave before ganglion compression, did not develop tachycardia or extrasystoles. Foramen ovale puncture elicited marked elevations of the systemic blood pressure in all patients. Ganglion compression further increased blood pressure, except in patients of Group 3, who had local anesthetic blockade of Meckel's cave.(ABSTRACT TRUNCATED AT 250 WORDS)

We studied the epithelial healing of denervated corneas in New Zealand albino rabbits with their left trigeminal ganglia surgically amputated. On the 14th day after amputation, the corneas were keratectomized (in 8.5 mm diameter) and documentation of the healing process began. We calculated the epithelial healing rate using simple regression analysis. We observed a mean healing rate of 0.463 +/- 0.059 mm2/hr (mean +/- SE) in the denervated corneas, compared to 0.609 +/- 0.031 mm2/hr in the control corneas; a statistically significant difference of P < 0.001. We performed scanning electron microscopic observation (SEM) at three points; before keratectomy, 48 hrs after keratectomy, and 14 days after keratectomy. SEM observation revealed that, in contrast to the control corneas, the surface of the epithelial cells in denervated corneas appeared rough with numerous exfoliating cells observed. This indicates that the epithelial cells might attach only weakly to the floor in denervated corneas. Transmission electron microscopic observation (TEM) performed at 48 hrs and 14 days after keratectomy also supports this finding. For example, the intercellular space is widened and fewer desmosomes are observed in denervated corneas. Using immunohistochemistry, the surface of the wound bed was covered with fibronectin in a similar fashion to the control. In the late stage, the denervated corneas demonstrated spontaneous epithelial breakdown with 83% of them having persistent epithelial defects. Epithelial healing in the control corneas displayed no abnormal signs. On the 14th day after keratectomy, these eyes were enucleated for immunohistochemistry using bromodeoxyuridine (Brd U) to observe dividing cells.(ABSTRACT TRUNCATED AT 250 WORDS)

We report a large trigeminal neurinoma in an 18-month-old child involving the Gasserian ganglion and all three divisions in a plexiform pattern. The tumour in the ophthalmic division extended all the way to the supraorbital nerve. The child presented with proptosis which had been observed since she was 4 months of age. There was a family history of neurofibromatosis.

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.

From 1980 through 1993 a series of 44 patients with trigeminal neurinomas was treated. Five of them were operated on for the remainder of the tumour as they had undergone previous surgery elsewhere, 35 were operated on for the first time, and 4 were not operated on for various reasons. An epidural approach to the neurinomas originating in the branches of the Vth nerve peripherally to the Gasserian ganglion (GG) was used. In the neurinomas originating in the GG or in the root of the Vth nerve, either an epidural-transdural approach or an epidural-transdural-transpetrous approach was used. All tumours operated on using the approach described in this article were completely removed. In 10 patients, the Vth nerve sensory deficits increased in comparison with preoperative deficits; in 9 their state remained unaltered; and in 11 the sensory function of the Vth nerve improved. In those patients who had experienced pre-operative atypical trigeminal pain, the pain disappeared after surgery. There was no additional treatment: radiosurgery, irradiation or chemotherapy. Histopathological examination did not reveal any malignant changes in the tumours in any of the patients. Based on our own experience and on the published data it is believed that the best treatment for trigeminal neurinomas is complete microsurgical removal of the lesion.

Patient comfort during percutaneous radiofrequency electrocoagulation for trigeminal neuralgia provides better working conditions for the surgeon and makes the patient more willing to return if a second procedure is necessary. This study evaluates five different regimens for analgesia and sedation including the standard of fentanyl and droperidol (Group A) and four other regimens, each containing midazolam. In a sixth group, droperidol was assessed for its antiemetic effects. Patients were medicated as follows: Group B, low-dose midazolam (3.0 mg average); Group C, low-dose midazolam (2.5 mg average) and oral diazepam (7.5 mg average) just before the procedure; Group D, high-dose midazolam (5.5 mg average); and Group E, high-dose midazolam (5.1 mg average) and oral diazepam. Medications were titrated to induce mild sedation in Groups A, B, and C and heavier sedation in Groups D and E. All patients received fentanyl and small doses of intravenous methohexital just before the cannula penetrated the foramen ovale and before radiofrequency electrocoagulation. At least 2 weeks later, patients reported their level of discomfort during the procedure and their recollection of the procedure on a 0 to 10 scale. In another group of 96 patients, 1.25 mg of droperidol was given in addition to the medications described for Groups D and E. There was a statistically significant improvement in comfort in Groups C, D, and E and added amnesia in Groups D and E. Vomiting occurred in none of the patients medicated with droperidol and in 5 of 143 patients who did not receive droperidol.(ABSTRACT TRUNCATED AT 250 WORDS)

The features of histamine-induced headache and its associated vascular responses were studied in 52 patients with different surgical lesions of the gasserian ganglion and in 12 control subjects. Certain features of headache (eg, intensity, type, and duration) were similar in patients and control subjects. However, the pain was absent on the side of the trigeminal lesion in 26 (50%) of the patients. This unilateral absence of pain was not related to the hypoesthesia that was caused by the operation, and it was associated with a decrease in vascular responses (histamine-induced facial flushing and increase in temperature) on the side operated on. These abnormalities were more prevalent in patients who had undergone thermocoagulation and presented with more severe damage of the trigeminal ganglion than in those who were subjected to trigeminal compression or glycerolization. The trigemino-vascular system seems to control headache of a vascular type and associated craniofacial vasodilatation in human subjects.

Neoplastic involvement of the trigeminal nerve was observed in 73 patients operated on in our institution for extra-axial tumours of the posterior and middle cranial fossae. It was defined as contact, compression, or infiltration. The nerve root was involved in 58 patients, the ganglion and/or the peripheral divisions in 9, all portions of the Vth nerve system in 6. A clinical trigeminal dysfunction was present in 44 patients (60%). Anatomico-surgical findings are correlated with clinical features and with tumour type. Typical trigeminal neuralgia was the complaint in 7 subjects; all of them presented an involvement of the sensory root. Post-operatively, 11 patients were relieved of their symptoms. The outcome is correlated with the anatomical findings and with the extent of surgical removal of the tumours. The importance of a careful evaluation of patients with trigeminal symptomatology is stressed.

Four hundred and seventy five patients with trigeminal neuralgia underwent cryotherapy (145), radiofrequency thermocoagulation (265) or microvascular decompression 65) and were then followed up for mean time of 45 months. Outcome of treatment was assessed not only by the clinicians but also by a postal questionnaire. The presence of anxiety and depression was determined and compared to 51 patients due to undergo surgery. The median time to recurrence for the cryotherapy patients and the radiofrequency thermocoagulation patients were 6 and 24 months, respectively. At 5 years 38% of the microvascular decompression patients had had a recurrence of neuralgia. There was one operative death in the radiofrequency thermocoagulation group. Patients in all three groups were satisfied with their treatment but the questionnaires showed that clinicians under-report the recurrence of pain and post operative complications. Pre-operatively depression and anxiety are high but post-operatively only 15% were depressed. Patients need careful pre-operative assessment which includes the McGill Pain Questionnaire and they should be given a choice about which surgical method would be most suitable in their case. Printed information should be available to supplement the consultation. This would ensure the patients' expectations matched up with the results as they would be aware of possible outcomes.

Stereotactic radiosurgery under local anesthesia with the Leksell Gamma Knife can effectively treat some patients with recurrent tic douloureux after unsuccessful medical/surgical procedures. Seven of 12 patients have shown complete relief or improvement of their trigeminal neuralgia. No complications have been observed.

The changes in arterial blood pressure which occur during the different steps of thermocoagulation of the trigeminal ganglion and rootlets are reported. The arterial blood pressure of 54 patients with trigeminal neuralgia was recorded continuously by catheterization of the radial artery. The maximal values were recorded (a) during the analgesic-sedation stage; (b) when the electrode came into contact with the base of the cranium during movement of the needle towards the foramen ovale; (c) during insertion of the electrode into the foramen ovale, and (d) during the thermocoagulation. One-way analysis of variance and Student's t test were used for analysis of the data. There was a significant increase of arterial blood pressure during the various stages of thermocoagulation.

The authors studied the long-term follow up of trigeminal neuralgic patients treated by retrogasserian rhizotomy with anhydrous glycerol injection (GI) or by microvascular decompression (MVD) and compared the satisfaction rates between them. Since 1983, 67 patients had been treated either by GI or MVD. The authors analyzed the results of the treatment by the method of questionnaire. Fifty-two patients of these 67 answered the questions, on which the present analysis was based. GI group consisted of 27 patients and MVD group 29 patients. The average follow-up period was 30.9 months in GI group (maximum follow-up: 84 months) and 50.9 months in MVD group (maximum follow-up: 95 months), respectively. The technique of GI used was Härtel's method with cisternography of Meckel's cave. The operations of MVD were performed by J.H. and A.K.. One patient out of 29 failed to be treated by MVD and two recurred within one year. On the other hand, 2 patients out of 27 failed to be treated by GI and 11 recurred. The recurrence was seen earlier in patients who had undergone GI, while one patient recurred the neuralgia at 76 months later. The recurrence rate in patients treated by MVD is 7.0% at 95 months, while that by GI is 49.0% at 84 months based on Kaplan-Meier survival analysis. The pathogenesis of trigeminal neuralgia is speculated to be an emphatic conduction caused by segmental demyelination and artificial synapse formation at the junction of central and peripheral myelin. The factors of this demyelination may be multiple sclerosis, basilar impression, aneurysm, arteriovenous malformation, atheroscleroses and natural aging.(ABSTRACT TRUNCATED AT 250 WORDS)

The neuralgia of the trigeminal nerve is the most frequent neuralgia of the cranial nerves. It is mostly seen in the elderly. In younger patients it must always be suspected as a symptomatic neuralgia. The course is recurrent and progressive. Spontaneous temporary remissions are usual. Later the pain becomes more frequent, unbearable and disabling. At first the therapy is a conservative one, the drug of choice is Carbamazepin, alternatively Phenytoin and Baclofen. If the conservative therapy fails, the only possible treatment is a neurosurgical one. Nowadays all methods aim at the Gasserian ganglion. In use are several percutaneous transoval procedures or the microvascular decompression through a craniotomy. Our surgical procedure of choice is the percutaneous thermorhizotomy in the Gasserian ganglion and the nerve root, where the pain-conducting fibers are destroyed, preserving tactile sensibility. This procedure is practically without vital hazards for the patient. It is applied in local anesthesia and a short intravenous analgesia. The recurrence rate of 32% is considerable, but the procedure can be repeated. The success cannot be deduced from the recurrence rate alone but must take into account the side effects of the procedure. These are mainly a loss of sensibility to touch by too aggressive rhizotomy and anesthesia of the cornea. By the criteria explained in the text we achieved a good result in 44%, a fair one in 25%, an indifferent one in 10% and a poor result in 7%. In 14% the result is unknown.

A series of 16 patients with meningiomas of Meckel's cave is reported. Trigeminal neuralgia, typical or atypical, was the initial symptom in 10 patients (62.5%). At admission, trigeminal signs and symptoms were present in 15 patients (93.7%); in 7 patients (43.7%), trigeminal dysfunction was combined with the impairment of other cranial nerves. On retrospective analysis, these patients fall into two clinical groups that differ also in prognosis. Group 1 comprises eight patients with trigeminal signs and symptoms only. These patients had small meningiomas strictly affecting Meckel's cave. Total removal of the tumor was achieved in seven of eight patients, without adjunctive postoperative neurological deficits. In this group, there were no tumor recurrences. Group 2 comprises the other eight patients in whom trigeminal dysfunction was combined with impairment of other cranial nerves. These patients had large tumors arising from Meckel's cave and secondarily invading the cavernous sinus (five patients) or extending into the posterior fossa (two patients) or largely growing into the middle fossa (one patient). Total removal was achieved in only one patient, and a worsening of the preoperative neurological status was observed in four patients; there were three cases of tumor progression. A subtemporal intradural approach (used in the past in every case) is still used for the small tumors of Group 1 with good results. Since 1985, for tumors involving the cavernous sinus, we have employed a frontotemporal craniotomy with extradural clinoidectomy and superior and lateral approach to the cavernous sinus. When the tumor extends toward the posterior fossa, we use a combined temporosuboccipital-transpetrosal approach.(ABSTRACT TRUNCATED AT 250 WORDS)

An unusual postoperative complication of percutaneous thermocoagulation of the gasserian ganglion is reported. Computed tomography and magnetic resonance imaging of the brain disclosed an intracerebral lesion following the surgical procedure. Some rare abnormalities of the skull base could increase the risk of such complications. A meticulous surgical technique with fluoroscopic and neurophysiological control is mandatory in any percutaneous procedure on the trigeminal ganglion.

The resulting changes in the regional cerebral blood flow of 18 patients suffering from idiopathic trigeminal neuralgia and treated by selective thermocoagulation of the trigeminal ganglion were measured by xenon-133 emission tomography. One hour after thermal stimulation, there was an asymmetric increase (P < 0.05) in cerebral blood flow, with a 14.7% mean increase in the ipsilateral cerebral hemisphere (P < 0.001) and a 12.7% mean increase in the contralateral side (P < 0.01). The increase in regional cerebral blood flow was not uniform but was most marked in the ipsilateral middle cerebral artery territory (P < 0.001). There was a slight decrease in cerebellar blood flow, but the reduction in the ipsilateral cerebellar lobe was less than that in the contralateral lobe (P < 0.01). The topography of the most significant changes coincided with that of the innervation of the cerebral vessels by the trigeminal nerve. Several mechanisms are involved in the increase in regional cerebral blood flow, including overall nonspecific activation of the central nervous system and local mechanisms associated with the trigeminal-vascular system.

The authors reviewed a series of 38 consecutive patients with trigeminal neuralgia treated by percutaneous thermocoagulation in 1984-90. In 10 patients in whom the result of the treatment was unsatisfactory the coagulation was repeated (in 2 out of 10 twice). The analysis of the results showed that good outcome was connected with permanent anaesthesia in the area innervated by the coagulated branch. If anaesthesia was not present 24 hours after the treatment, it suggested that an insufficient lesion was done and consequently unsatisfactory result was likely. In patients in whom there was a sensory impairment after either thermocoagulation or other form of treatment (injection of alcohol or rhizotomy) repeated thermocoagulation not only did not give good results but could lead to worsening of the pain.

The authors reviewed a series of 38 consecutive patients with trigeminal neuralgia treated with percutaneous thermocoagulation in years 1984-90. In 10 patients in whom the result of treatment was unsatisfactory the coagulation was repeated (in 2 out of 10 threefold). The analysis of the results showed that good outcome was connected with permanent anaesthesia in the area innervated by the coagulated branch. If the anaesthesia was not present 24 hours after the treatment, it suggested that an insufficient lesion was done and consequently unsatisfactory result was likely. In patients in whom there was sensory impairment after either thermocoagulation or other form of treatment (injection of alcohol or rhizotomy) repeated thermocoagulation not only did not give good results but could lead to worsening of pain.

Marked hyperemia accompanies reperfusion after ischemia in the brain, and may account for the propensity of cerebral hemorrhage to follow embolic stroke or carotid endarterectomy, and for the morbidity that follows head injury or the ligation of large arteriovenous malformations. To evaluate the contribution of trigeminal sensory fibers to the hyperemic response, CBF was determined in 12 symmetrical brain regions, using microspheres with up to five different isotopic labels, in four groups of cats. Measurements were made at 15-min intervals for up to 2 h of reperfusion after global cerebral ischemia induced by four-vessel occlusion combined with systemic hypotension of either 10- or 20-min duration. In normal animals, hyperemia in cortical gray matter 30 min after reperfusion was significantly greater after 20 min (n = 10) than after 10 min (n = 7) of ischemia (312 ml/100 g/min versus 245 ml/100 g/min; p less than 0.01). CBF returned to preischemic levels approximately 45 min after reperfusion and was reduced to approximately 65% of basal CBF for the remaining 75 min. In cats subjected to chronic trigeminal ganglionectomy (n = 15), postocclusive hyperemia in cortical gray matter was attenuated by up to 48% on the denervated side (249 versus 150 ml/100 g/min; p less than 0.01) after 10 min of ischemia. This effect was maximal in the middle cerebral artery (MCA) territory, and was confined to regions known to receive a trigeminal innervation. In these animals, substance P (SP) levels in the MCA were reduced by 64% (p less than 0.01), and the density of nerve fibers containing calcitonin gene-related peptide (but not vasoactive intestinal polypeptide or neuropeptide Y) was decreased markedly on the lesioned side. Topical application of capsaicin (100 nM; 50 microliters) to the middle or posterior temporal branch of the MCA 10-14 days before ischemia decreased SP levels by 36%. Postocclusive hyperemia in cortical gray matter was attenuated throughout the ipsilateral hemisphere by up to 58%, but the cerebral vascular response to hypercapnia (PaCO2 = 60 mm Hg) was unimpaired. The duration of hyperemia and the severity of the delayed hypoperfusion were not influenced by trigeminalectomy, capsaicin application, or the intravenous administration of ATP. These data demonstrate the importance of neurogenic mechanisms in the development of postischemic hyperperfusion, and suggest the potential utility of strategies aimed at blocking axon reflex-like mechanisms to reduce severe cortical hyperemia.

Severe pain which cannot be controlled medically is the major factor for which patients seek surgical treatment for trigeminal neuralgia. Patients should be neurologically screened and have an enhanced CT scan prior to surgery in order to exclude a secondary cause for the disease. Peripheral techniques such as cryotherapy and alcohol injections give short-term pain relief but have few complications. The most popular operation, radiofrequency thermocoagulation in the Gasserian ganglion, has a mean recurrence of 3 years, but leaves patients with extensive sensory loss. Microvascular decompression and partial rhizotomy are major neurosurgical procedures that have a low recurrence rate but carry a risk of death and serious morbidity. Patients should be more involved in the choice of surgery.

22 patients undergoing percutaneous microcompression of Gasserian ganglion for the treatment of trigeminal neuralgia were monitored intraoperatively by means of trigeminal evoked potentials (TEPs). The second trigeminal branch was stimulated at the maxillary foramen; evoked responses were recorded using subcutaneous electrodes placed over the scalp. TEPs presented several short-latency waves (called W1, W2, W3, P4, N5, P6, N10) which are generated before and after the ganglion (W1, W2, W3), in the brain stem (P4, N5, P6) and possibly in the cortex (N10); other waves occur within 150 ms after the stimulus (late waves). During compression, W1 did not change, while W2 and W3 as well as P4, N5, P6, N10 and late waves decreased in amplitude: this pattern was noted in the patients who presented with pain relief during the follow-up period. On the contrary, the patients who suffered from pain recurrence did not show similar intraoperative TEP changes. In conclusion, intraoperative TEP derangements may be related to the effectiveness of the compression on the Gasserian ganglion.

Personal seven-year experience (1984-1990) with the application of semilunar ganglionectomy in 25 patients with basic indication for pancreatic cancer (20 patients) and chronic pancreatitis (5 patients). Attention is called on the basic points in the original technique of Legé and the authors' own modifications of this technique. The indications and contraindications for performing the operative intervention were determined. The early postoperative results in 84 per cent of the cases (regardless of the type of diseases) were excellent as regards the pain; in the remote postoperative period the results were poor. The causes of the poor results of semilunar ganglionectomy are analyzed. The most common cause was the generalization of the malignant processes in the pancreas and the faulty performance of the intervention. The major importance of this operation in the treatment of chronic indurative pancreatitis with narrow pancreatic canals and its value when combined with other derivation methods in the operative treatment of pancreatic surgical diseases are pointed out.

The influence of neuroeffector mechanisms in the regulation of postischemic cerebral blood flow was investigated by microsphere determination in 8 cats after chronic unilateral vascular deafferentation by trigeminal ganglionectomy. The animals were subjected to 90 min of reperfusion following 10 min of global ischemia induced by 4-vessel occlusion and systemic hypotension. Cortical hyperemia 30 min after reperfusion was attenuated by up to 48% in cortical gray matter ipsilateral to the side of trigeminal ganglionectomy (p less than 0.01). Axon reflex mechanisms involving the release of neuropeptides from peripheral sensory nerve fibers, such as substance P (SP), calcitonin gene-related peptide (CGRP) and neurokinin A (NKA), mediate this response. SP and NKA cause vasodilation by endothelium-dependent mechanisms (endothelium-dependent relaxing factor), whereas CGRP relaxes vascular smooth muscle by direct receptor interactions. Studies were therefore undertaken to determine the extent to which endothelium-dependent mechanisms mediate the hyperemia following global cerebral ischemia. In 7 intact cats, the postischemic response of pial arterioles to the topical application of acetylcholine (ACh; 10(-7) M), an endothelial-dependent vasodilator, was measured using a closed cranial window technique. Although ACh increased pial arteriolar caliber by 17% under resting conditions, the same dose elicited a vasoconstrictor response (87% of pre-ACh diameter 30 min after reperfusion) for the first 60 min of reperfusion after 10 min of ischemia. ACh-induced vasodilation was restored by 75 min (105%), but was less than control even at 120 min (109 vs. 117%; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)