Top 25 Cited Gamma Knife® Surgery Articles — Trigeminal Neuralgia
Jean Régis, Philippe Metellus, Henry Dufour, Pierre-Hughes Roche, Xavier Muracciole, William Pellet, Francois Grisoli and Jean-Claude Peragut
Object. This study was directed to evaluate the potential role of gamma knife surgery (GKS) in the treatment of secondary trigeminal neuralgia (TN). The authors have identified three anatomicoclinical types of secondary TN requiring different radiosurgical approaches.
Methods. Pain control was retrospectively analyzed in a population of patients harboring tumors of the middle or posterior fossa that involved the trigeminal nerve pathway. This series included 53 patients (39 women and 14 men) treated using GKS between July 1992 and June 1997. The median follow-up period was 55 months. Treatment strategies differed according to lesion type, topography, and size, as well as visibility of the fifth cranial nerve in the prepontine cistern. Three different treatment groups were established. When the primary goal was treatment of the lesion (Group IV, 46 patients) we obtained pain cessation in 79.5% of cases. In some patients in whom GKS was not indicated for treatment of the lesion, TN was treated by targeting the fifth nerve directly in the prepontine cistern if visible (Group II, three patients) or in the part of the lesion including this nerve if the nerve root could not be identified (Group III, four patients). No deaths and no radiosurgically induced adverse effects were observed, but in two cases there was slight hypesthesia (Group IV). The neuropathic component of the facial pain appeared to be poorly sensitive to radiosurgery. At the last follow-up examination, six patients (13.3%) exhibited recurrent pain, which was complete in four cases (8.8%) and partial in two (4.4%).
Conclusions. The results of GKS regarding facial pain control are very similar to those achieved by microsurgery according to series published in the literature. Nevertheless, the low rate of morbidity and the greater comfort afforded the patient render GKS safer and thus more attractive.
Satoshi Maesawa, Camille Salame, John C. Flickinger, Stephen Pirris, Douglas Kondziolka and L. Dade Lunsford
Object. Stereotactic radiosurgery is an increasingly used and the least invasive surgical option for patients with trigeminal neuralgia. In this study, the authors investigate the clinical outcomes in patients treated with this procedure.
Methods. Independently acquired data from 220 patients with idiopathic trigeminal neuralgia who underwent gamma knife radiosurgery were reviewed. The median age was 70 years (range 26–92 years). Most patients had typical features of trigeminal neuralgia, although 16 (7.3%) described additional atypical features. One hundred thirty-five patients (61.4%) had previously undergone surgery and 80 (36.4%) had some degree of sensory disturbance related to the earlier surgery.
Patients were followed for a maximum of 6.5 years (median 2 years). Complete or partial relief was achieved in 85.6% of patients at 1 year. Complete pain relief was achieved in 64.9% of patients at 6 months, 70.3% at 1 year, and 75.4% at 33 months. Patients with an atypical pain component had a lower rate of pain relief (p = 0.025). Because of recurrences, only 55.8% of patients had complete or partial pain relief at 5 years. The absence of preoperative sensory disturbance (p = 0.02) or previous surgery (p = 0.01) correlated with an increased proportion of patients who experienced complete or partial pain relief over time. Thirty patients (13.6%) reported pain recurrence 2 to 58 months after initial relief (median 15.4 months). Only 17 patients (10.2% at 2 years) developed new or increased subjective facial paresthesia or numbness, including one who developed deafferentation pain.
Conclusions. Radiosurgery for idiopathic trigeminal neuralgia was safe and effective, and it provided benefit to a patient population with a high frequency of prior surgical intervention.
Douglas Kondziolka, L. Dade Lunsford, John C. Flickinger, Ronald F. Young, Sandra Vermeulen, Christopher M. Duma, Deane B. Jacques, Robert W. Rand, Jean Regis, Jean-Claude Peragut, Luis Manera, Mel H. Epstein and Christer Lindquist
✓ A multiinstitutional study was conducted to evaluate the technique, dose-selection parameters, and results of gamma knife stereotactic radiosurgery in the management of trigeminal neuralgia. Fifty patients at five centers underwent radiosurgery performed with a single 4-mm isocenter targeted at the nerve root entry zone. Thirty-two patients had undergone prior surgery, and the mean number of procedures that had been performed was 2.8 (range 1–7). The target dose of the radiosurgery used in the current study varied from 60 to 90 Gy. The median follow-up period after radiosurgery was 18 months (range 11–36 months). Twenty-nine patients (58%) responded with excellent control (pain free), 18 (36%) obtained good control (50%–90% relief), and three (6%) experienced treatment failure. The median time to pain relief was 1 month (range 1 day–6.7 months). Responses remained consistent for up to 3 years postradiosurgery in all cases except three (6%) in which the patients had pain recurrence at 5, 7, and 10 months. At 2 years, 54% of patients were pain free and 88% had 50% to 100% relief.
A maximum radiosurgical dose of 70 Gy or greater was associated with a significantly greater chance of complete pain relief (72% vs. 9%, p = 0.0003). Three patients (6%) developed increased facial paresthesia after radiosurgery, which resolved totally in one case and improved in another. No patient developed other deficits or deafferentation pain. The proximal trigeminal nerve and root entry zone, which is well defined on magnetic resonance imaging, is an appropriate anatomical target for radiosurgery. Radiosurgery using the gamma unit is an additional effective surgical approach for the management of medically or surgically refractory trigeminal neuralgia. A longer-term follow-up review is warranted.