Repeat Gamma Knife surgery for trigeminal neuralgia: long-term results

Abstract

Object The purpose of this study was to assess the long-term outcome achieved after repeat Gamma Knife surgery (GKS) for trigeminal neuralgia (TN) using a uniform treatment plan. Methods Between 1985 and 2010, 53 patients underwent repeat GKS for refractory TN. In the initial GKS, which involved targeting the root entry zone of the trigeminal nerve, a maximal dose of 80 Gy was used with a 4-mm collimator so that the 50% isodose line abutted the pons. In the second GKS, the treatment plan consisted of a 70-Gy dose directed at a target 4–5 mm distal to the first target on the trigeminal nerve. The mean follow-up duration in these patients was 42 months. Outcomes were defined using the Marseille scale: excellent (Class I or II, no pain with or without medications), good (Class III or IV, ≥ 50% relief), and poor (Class V, < 50% relief). Results Trigeminal neuralgia pain was controlled (≥ 50% improvement with or without medications) after repeat GKS in 70% of patients at 1 year, 50% at 3 years, 50% at 5 years, and 50% at 10 years, as defined by a Kaplan-Meier analysis. A correlation was found between facial numbness and pain relief (p = 0.047). No difference was found between patients with Type 1 TN and those with Type 2 TN, and there was no correlation between the best relief obtained and long-term durability of relief from pain. Twenty-two patients (47.8%) described their trigeminal dysfunction in the following manner: numbness (45.6%), dry eye (10.9%), taste change (8.7%), or jaw weakness (2.2%). In only 8.7% of cases did the patient experience facial numbness that was regarded as bothersome. Conclusions Repeat GKS for TN at the doses used provides substantial long-term relief. Treatment failure occurred up to 28 months after the second GKS. Facial numbness correlated with more durable pain relief after repeat GKS in this series.

Feasibility of Multiple Repeat Gamma Knife Radiosurgeries for Trigeminal Neuralgia: A Case Report and Review of the Literature

“…Dvorak et al showed a dose-response relationship for both pain control and development of side effects, with doses above 130 Gy more likely to result in a new dysfunction, as well as improved pain control [9]. Other studies have demonstrated the same correlation between pain control and development of unwanted side effects [18–20]. Another study notes that at cumulative doses above 163 Gy, the rate of bothersome numbness was in the range of 16% [11].…”

Repeat Gamma-Knife Radiosurgery for Refractory or Recurrent Trigeminal Neuralgia with Consideration About the Optimal Second Dose

“…In some studies, root entry zone radiation dose were suggested to be important and root entry zone targets were used (3,15,20,36). In the other studies, retrogasserian targets were also effective and suggested to result in lower complication rate (23,35,44).…”

“…For recurrent or refractory trigeminal neuralgia, repeat gamma-knife radiosurgery (GKS) is known as an effective treatment with low complication rate (3,4,8,15,17,18,20,34,36,37,41,(44)(45)(46)(47).…”

Clinical Outcomes of Gamma Knife Radiosurgery in the Treatment of Patients with Trigeminal Neuralgia

“…We reviewed six studies evaluating patients treated more than once with GKRS [27–32] (Table 2). Of these six articles, two [29, 32] utilized the BNI pain intensity scale [26].…”

“…Kimball et al [27] treated 53 patients with repeat GKRS and analyzed the patients not lost during followup using the Marseille scale [22], which categorizes patients into one of five classes, with a higher class statistically indicating a worse prognosis for the patient. With a mean followup of 42 months, 20 patients (43.5%) were categorized in Marseille class I-II, six patients (13%) were categorized in Marseille class III-IV, and 20 patients (43.5%) were categorized in Marseille class V. The authors also reported a statistically significant ( P = 0.047) correlation between facial numbness and superior long-term pain relief.…”