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gamma_knife_radiosurgery_for_trigeminal_neuralgia

Gamma Knife radiosurgery for trigeminal neuralgia

Gamma knife radiosurgery (GKRS) is one of the alternatives for treatment for classical trigeminal neuralgia (TN).

The first use of SRS by Lars Leksell was for the treatment of trigeminal neuralgia. Initially, this was reserved for refractory cases following multiple operations 1).

The Leksell Gamma Knife and the Accuray CyberKnife systems have been used in the radiosurgical treatment of trigeminal neuralgia. The 2 techniques use different delivery methods and different treatment parameters. In the past, CyberKnife treatments have been associated with an increased incidence of treatment-related complications, such as facial numbness.

CyberKnife radiosurgical parameters can be optimized to mimic the dose distribution of Gamma Knife plans. However, Gamma Knife plans result in superior sparing of critical structures (brainstem, temporal lobe,and cranial nerves VII and VIII) and in steeper dose fall off away from the target. The clinical significance of these effects is unknown 2).

Indications

Generally recommended for patients with co-morbidities, high-risk medical illness, pain refractory to prior surgical procedures, or those on anticoagulants (anticoagulation does not have to be reversed to have SRS).

Mechanism

Treatment plan

4 -5 mm isocenter in the trigeminal nerve root entry zone identified on MRI. Use 70–80 Gy at the center, keeping the 80% isodose curve outside of the brainstem.

Results: Significant pain reduction after initial SRS: 80–96% 3) 4) 5) 6) but only ≈ 65% become pain free. Median latency to pain relief: 3 months (range: 1 d-13 months) 7).

Recurrent pain occurs with in three years in 10–25%. Patients with TN and multiple sclerosis are less likely to respond to SRS than those without MS. SRS can be repeated, but only after four months following the original procedure.

Outcome

Repeat Radiosurgery for Trigeminal Neuralgia

Case series

A total of 263 patients contributed by 9 member tertiary referral Gamma Knife centers (2 in Canada and 7 in USA) of the International Gamma Knife Research Consortium (IGKRF) constituted this study.

The median latency period of Facial pain response (PR) after SRS was 1 mo. Reasonable pain control (Barrow Neurological Institute Pain Scale I-IIIb) was achieved in 232 patients (88.2%). The median maintenance period from SRS was 14.1 months (range, 10 days to 10 years). The actuarial reasonable pain control maintenance rates at 1 yr, 2 yr, and 4 yr were 54%, 35%, and 24%, respectively. There was a correlation between the status of achieving BNI-I and the maintenance of facial pain recurrence-free rate. The median recurrence-free rate was 36 mo and 12.2 mo in patients achieving BNI-I and BNI > I, respectively (P = .046). Among 210 patients with known status of post-SRS complications, the new-onset of facial numbness (BNI-I or II) after SRS occurred in 21 patients (10%).

In this largest series SRS offers a reasonable benefit to risk profile for patients who have exhausted medical management. More favorable initial response to SRS may predict a long-lasting pain control 8).

2016

One hundred seventeen patients with medically refractory TN treated by GKRS at the Department of Functional Neurosurgery and Gamma Knife Radiosurgery, and Department of Neurology, Ruber International Hospital, Madrid, Spain were followed up between 1993 and 2011. Mean maximum dose was 86.5 Gy (range: 80-90 Gy; median: 90 Gy). Clinical response was defined based on the Burchiel classification. They considered classes I and II as a complete response. For toxicity, they use the Barrow Neurological Institute Pain Scale. Mean duration of follow-up was 66 months (range: 24-171 months).

Complete response at last follow-up in our patients was 81%, with an excellent response while off medication in 52%. Pain-free rates without medication (class I) were 85% at 3 years (confidence interval [CI]: 78%-94%), 81% at 5 years (CI: 72%-91%), and 76% at 7 years (CI: 65%-90%). Complete response rates (classes I-II) were 91% at 3 years (CI: 86%-97%), 86% at 5 years (CI: 79%-93%), and 82% at 7 years (CI: 72%-93%). Poor treatment response rates differed significantly between patients who had undergone previous surgery and were refractory to management with medication prior to GKRS. New or worsening facial numbness was reported in 32.5% (30% score II and 2.5% score III). No anesthesia dolorosa was reported. Permanent recurrence pain rate was 12%.

GKRS achieved favorable outcomes compared with surgery in terms of pain relief and complication rates in our cohort of patients, notwithstanding decreasing pain-free survival rates over time. They consider GKRS to be an initial treatment in the management of medically intractable TN in selected patients 9).


In a single-center, retrospective comparative study, 202 patients with MS and concomitant TN were evaluated. A minimum follow-up of 24 months was required. Patients with a history of microvascular decompression or previous intervention were excluded. There were 78 PBC procedures performed and 124 first-dosage GKRS procedures for a total of 202 patients between February 2009 and December 2013. The PBC procedures were successfully completed in all cases. The two groups were compared with regards to initial effect, duration of effect, and rate of complication(s), including the type and severity of the complication(s).

Immediate pain relief resulted in 87% of patients treated with PBC and in 23% of patients treated with GKRS. The Kaplan-Meier plots for the two treatment modalities were similar. The 50% recurrence rate was at 12 months for the PBC and 18 months for the GKRS. The rates of complication (excluding numbness) were 3% for GKRS and 21% for PBC. The difference was statistically significant (Chi-square test, p = 0.03).

PBC and GKRS are effective techniques for the treatment of TN in patients with MS, with GKRS presenting fewer complications and superior long-term relief. For these reasons, we consider GKRS as the first option for the treatment of TN in MS patients, reserving PBC for patients with acute, intractable pain 10).

References

1)
Lunsford LD. Comment on Taha J M and Tew J M: Comparison of Surgical Treatmen ts for Trigemin al Neuralgia: Reevaluation of Radiofrequency Rhizotomy. Neurosurgery. 1996; 38
2)
Descovich M, Sneed PK, Barbaro NM, McDermott MW, Chuang CF, Barani IJ, Nakamura JL, Lijun M. A dosimetric comparison between Gamma Knife and CyberKnife treatment plans for trigeminal neuralgia. J Neurosurg. 2010 Dec;113 Suppl:199-206. PubMed PMID: 21222296.
3)
Brisman R. Gamma knife surgery with a dose fo 75 to 76.8 Gray for trigeminal neuralgia. J Neurosurg. 2004; 100:848–854
4)
Pollock BE, Phuong LK, Foote RL, Sta ord SL, Gorman DA. High-dose trigeminal neuralgia radiosurgery associated with increased risk of trigeminal nerve dysfunction. Neurosurgery. 2001; 49:58–62; discussion 62-4
5)
Kondziolka D, Lunsford LD, Flickinger JC. Stereotact ic radiosurgery for the treatment of trigeminal neuralgia. Clin J Pain. 2002; 18:42–47
6)
Massager N, Lorenzoni J, Devriendt D, Desmedt F, Brotch i J, Levivier M. Gamma kn ife surgery for idiopathic trigeminal neuralgia performed using a far-anterior cisternal target and a high dose of radiation. J Neurosurg. 2004; 100:597–605
7)
Urgosik D, Liscak R, Novotny J, Jr, Vymazal J, Vladyka V. Treatment of essential trigeminal neuralgia with gamma knife surgery. J Neurosurg. 2005; 102 Suppl:29–33
8)
Xu Z, Mathieu D, Heroux F, Abbassy M, Barnett G, Mohammadi AM, Kano H, Caruso J, Shih HH, Grills IS, Lee K, Krishnan S, Kaufmann AM, Lee JYK, Alonso-Basanta M, Kerr M, Pierce J, Kondziolka D, Hess JA, Gerrard J, Chiang V, Lunsford LD, Sheehan JP. Stereotactic Radiosurgery for Trigeminal Neuralgia in Patients With Multiple Sclerosis: A Multicenter Study. Neurosurgery. 2019 Feb 1;84(2):499-505. doi: 10.1093/neuros/nyy142. PubMed PMID: 29688562.
9)
Martínez Moreno NE, Gutiérrez-Sárraga J, Rey-Portolés G, Jiménez-Huete A, Martínez Álvarez R. Long-Term Outcomes in the Treatment of Classical Trigeminal Neuralgia by Gamma Knife Radiosurgery: A Retrospective Study in Patients With Minimum 2-Year Follow-up. Neurosurgery. 2016 Dec;79(6):879-888. PubMed PMID: 27560193.
10)
Alvarez-Pinzon AM, Wolf AL, Swedberg HN, Barkley KA, Cucalon J, Curia L, Valerio JE. Comparison of Percutaneous Retrograsserian Balloon Compression and Gamma Knife Radiosurgery for the Treatment of Trigeminal Neuralgia in Multiple Sclerosis: A Clinical Research Study Article. World Neurosurg. 2016 Oct 15. pii: S1878-8750(16)31016-6. doi: 10.1016/j.wneu.2016.10.028. PubMed PMID: 27756676.
gamma_knife_radiosurgery_for_trigeminal_neuralgia.txt · Last modified: 2019/07/13 11:28 by administrador