A multiarray mapping method to minimize morbidity from thermocoagulation as treatment of refractory trigeminal neuralgia.

BACKGROUND: Conventional percutaneous thermocoagulation of postgasserian fibers has shown high success rates, with significant residual morbidity. METHODS: This communication summarizes conclusions of multiple publications on our computerized mapping method and technique, and presents new data on short- and long-term results on trigeminal pain, including an actuarial analysis, complications. RESULTS: In TTN, 97.4% of 75 procedures produced initial pain relief without medication. In all, 84.7% of appropriate verbal responses were achieved by proper location of the needle at the chosen target, requiring an average of 1.45 tracts per procedure. Needle tip was located between 1 and 15 mm below the sellar floor in 97.0% of procedures and in an angle of 40 degrees to 80 degrees regarding the clivus profile projection in 99.1%. A 93% reduction of corneal analgesia and a 100% suppression of major dysesthesias and cranial nerve palsies were found. CONCLUSION: We have shown a significant reduction of morbidity from percutaneous thermocoagulation of postgasserian fibers with similar short- and long-term results as those shown in 11 recently selected series. Strict adherence to all details of our new method and technique is essential. Future multiinstitutional studies are needed to confirm and enrich this small series.

A multiarray electrode mapping method for percutaneous thermocoagulation as treatment of trigeminal neuralgia. Technical note on a series of 178 consecutive procedures.

BACKGROUND: We describe our method and mapping technique of the trigeminal nerve using a quadripolar electrode to minimize morbidity of percutaneous thermocoagulation as treatment of trigeminal neuralgia. METHOD: Of 381 patients selected for postgasserian thermocoagulation, 178 consecutive procedures were carried out using, in most cases, our painless and ambulatory method and technique. All patients were preoperatively subjected to 3-dimensional constructive interference in steady-state magnetic resonance and magnetic resonance angiography. Transgasserian introduction of our quadripolar multiarray electrode under constant fluoroscopic monitoring is used with systematic recording of radiologic angles at, in front of, and behind the clivus profile, always below the selar floor. The individual's somatotopic map based on the verbal responses of 34 facial subsegments in lieu of the usual 3 is carefully established. Lesions are aimed at the trigger of pain and restricted to fibers with the lowest thresholds. Maximal lesions are one third the size used in conventional thermocoagulation. Lesions attempt to avoid damage to the first division, uninvolved fibers, and the motor division. RESULTS: Pre- and postoperatory thresholds demonstrate that trigger-aimed small lesions do not extend to unwanted subsegments. The described technique can minimize unnecessary complications from percutaneous thermocoagulation.

Reducing unnecessary morbidity from percutaneous thermocoagulation in the treatment of trigeminal neuralgia--part C: a starting point for a somatotopic map of the human Gasserian ganglion.

OBJECTIVES: An original method and technique has been designed to reduce the significant morbidity associated with techniques currently used for percutaneous thermocoagulation in the treatment of trigeminal neuralgia. The current report deals with the mathematical and biostatistical analysis of verbal responses gathered using such a method in an attempt, as a starting point, to establish the somatotopic organization of the human gasserian ganglion. METHOD: A correspondence analysis was used to validate verbal responses. These were ordered in three 34 x 34 matrices, according the initial sequence of 34 subsegments of the face, which was based on the operative experience of one of the authors. After using a filter for the consistency of responses, and a maximum threshold below 0.5 V, 967 responses from 99 patients were selected for analysis. The frequencies obtained from each subsegment were compared, using all the possible pairwise combinations of the subsegments of the face, and the sequences were ordered using the least contradictory criterion. RESULTS: The incidence of each verbal response within each trigeminal division was analysed, resulting in a proposal of a sequence of 20 subsegments of the gasserian ganglion, listed from the depth to the surface. DISCUSSION: From the strict clinical point of view, the somatotopic map of each individual is invariant and easily analysed over long time periods. Its precise knowledge is critical for inducing smaller, properly placed lesions, in order to avoid unnecessary morbidity from percutaneous thermocoagulation in the treatment of trigeminal neuralgia. The proposed sequence of the gasserian somatotopic organization will be hopefully a useful guide for those interested in trigeminal physiological organization as well as for the therapeutic exploration of gasserian trigeminal fibers.

Reducing unnecessary morbidity from percutaneous thermocoagulation in the treatment of trigeminal neuralgia. Part B: a computerized protocol for quantitative analysis of data for radiofrequency thermocoagulation with the quadripolar electrode method and technique.

OBJECTIVES: An original method and technique was designed to reduce the still significant morbidity of percutaneous thermocoagulation in the treatment of trigeminal neuralgia. A critical part of this technique is the computerized analysis of data, which is the subject of this report. METHOD: We fully describe the computerized program for data collection and analysis, which is designed to evaluate addressed and unaddressed aspects of trigeminal neuralgia using the quadripolar electrode method and technique. RESULTS AND DISCUSSION: The computerized analysis of multiple clinical and radiological variables, including verbal responses from 34 facial subsegments, allows the description of the somatotopic map of the human gasserian ganglion, and the conclusions propose to attempt to abolish unnecessary residual morbidity of thermocoagulation in the treatment of trigeminal neuralgia.