Gamma Knife Radiosurgery for trigeminal neuralgia outcome

Gamma Knife Radiosurgery for trigeminal neuralgia outcome

Significant pain reduction after initial SRS: 80–96% 1) 2) 3) 4) but only ≈ 65% become pain free. Median latency to pain relief: 3 months (range: 1 d-13 months) 5).

Recurrent pain occurs within 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.

Favorable prognosticators: higher radiation doses, previously unoperated patient, absence of atypical pain component, normal pre-treatment sensory function 6).

Side effects: Hypesthesia occurred in 20% after initial SRS, and in 32% of those requiring repeat treatment 7) (higher rates associated with higher radiation doses) 8).


Outcome prediction of this modality is very important for proper case selection. The aim of a study was to create artificial neural networks (ANN) to predict the clinical outcomes after gamma knife radiosurgery (GKRS) in patients with TN, based on preoperative clinical factors.

They used the clinical findings of 155 patients who were underwent GKRS (from March 2000 to march 2015) at Iran Gamma Knife center, TehranIran. Univariate analysis was performed for a long list of risk factors, and those with P-Value < 0.2 were used to create back-propagation ANN models to predict pain reduction and hypoesthesia after GKRS. Pain reduction was defined as BNI score 3a or lower and hypoesthesia was defined as BNI score 3 or 4.

Typical trigeminal neuralgia (TTN) (P-Value = 0.018) and age>65 (P-Value = 0.040) were significantly associated with successful pain reduction and three other variables including radiation dosage >85 (P-Value = 0.098), negative history of diabetes mellitus (P-Value = 0.133) and depression (P-Value = 0.190). On the other hand, radio dosage > 85 (P-Value = 0.008) was significantly associated with hypoesthesia, other related risk factors (with p-Value < 0.2), were history of multiple sclerosis (P-Value = 0.106), pain duration more than 10 years before GKRS (P-Value = 0.115), history of depression (P-Value = 0.139), history of percutaneous ablative procedures (P-Value = 0.148) and history of diabetes mellitus (P-Value = 0.169).ANN models could predict pain reduction and hypoesthesia with the accuracy of 84.5% and 91.5% respectively. By mutual elimination of each factor in this model we could also evaluate the contribution of each factor in the predictive performance of ANN.

The findings show that artificial neural networks can predict post operative outcomes in patients who underwent GKRS with a high level of accuracy. Also the contribution of each factor in the prediction of outcomes can be determined using the trained network 9).

Case series

The long-term results in 130 patients who underwent radiosurgery for classical TN and were subsequently monitored through at least 7 years (median = 9.9, range = 7-14.5) of follow-up.

The median age was 66.5 years. A total of 122 patients (93.8%) became pain free (median delay = 15 days) after the radiosurgery procedure (Barrow Neurological Institute, BNI class I-IIIa). The probability of remaining pain free without medication at 3, 5, 7 and 10 years was 77.9, 73.8, 68 and 51.5%, respectively. Fifty-six patients (45.9%) who were initially pain free experienced recurrent pain (median delay = 73.1 months). However, at 10 years, of the initial 130 patients, 67.7% were free of any recurrence requiring new surgery (BNI class I-IIIa). The new hypesthesia rate was 20.8% (median delay of onset = 12 months), and only 1 patient (0.8%) reported very bothersome hypesthesia.

The long-term results were comparable to those from our general series (recently published), and the high probability of long-lasting pain relief and rarity of consequential complications of radiosurgery may suggest it as a first- and/or second-line treatment for classical, drug-resistant TN 10).


Thirty-six consecutive patients with medically intractable TN received a median radiation dose of 45 Gy applied with a single 4-mm isocenter to the affected trigeminal nerve. Follow-up data were obtained by clinical examination and telephone questionnaire. Outcome results were categorized based on the Barrow Neurological Institute (BNI) pain scale with BNI I-III considered to be good outcomes and BNI IV-V considered as treatment failure. BNI facial numbness score was used to assess treatment complications.

The incidence of early pain relief was high (80.5 %) and relief was noted in an average of 1.6 months after treatment. At minimum follow-up of 3 years, 67 % were pain free (BNI I) and 75 % had good treatment outcome. At a mean last follow-up of 69 months, 32 % were free from any pain and 63 % were free from severe pain. Bothersome posttreatment facial numbness was reported in 11 % of the patients. A statistically significant correlation was found between age and recurrence of any pain with age >70 predicting a more favorable outcome after radiosurgery.

The success rate of GKRS for treatment of medically intractable TN declines over time with 32 % reporting ideal outcome and 63 % reporting good outcome. Patients older than age 70 are good candidates for radiosurgery. This data should help in setting realistic expectations for weighing the various available treatment options 11).


From 1994 to 2009, 40 consecutive patients with typical, intractable TN received GKRS. Among these, 22 patients were followed for >60 months. The mean maximum radiation dose was 77.1 Gy (65.2-83.6 Gy), and the 4 mm collimator was used to target the radiation to the root entry zone.

The mean age was 61.5 years (25-84 years). The mean follow-up period was 92.2 months (60-144 months). According to the pain intensity scale in the last follow-up, 6 cases were grades I-II (pain-free with or without medication; 27.3%) and 7 cases were grade IV-V (<50% pain relief with medication or no pain relief; 31.8%). There was 1 case (facial dysesthesia) with post-operative complications (4.54%).

The long-term results of GKRS for TN are not as satisfactory as those of microvascular decompression and other conventional modalities, but GKRS is a safe, effective and minimally invasive technique which might be considered a first-line therapy for a limited group of patients for whom a more invasive kind of treatment is unsuitable 12).


Kondziolka et al., evaluated pain relief and treatment morbidity after trigeminal neuralgia radiosurgery.

All evaluable patients (n = 106) had medically or surgically refractory trigeminal neuralgia. A single 4-mm isocenter of radiation was focused on the proximal trigeminal nerve just anterior to the pons. For follow-up an independent physician who was unaware of treatment parameters contacted all patients.

After radiosurgery, 64 patients (60%) became free of pain and required no medical therapy (excellent result), 18 (17%) had a 50% to 90% reduction (good result) in pain severity or frequency (some still used medications), and 9 (9%) had slight improvement. At last follow-up (median, 18 months; range, 6-48 months), 77% of patients maintained significant relief (good plus excellent results). Only 6 (10%) of 64 patients who initially attained complete relief had some recurrent pain. Radiosurgery dose (70-90 Gy), age, surgical history, or facial sensory loss did not correlate with pain relief. Poorer results were found in patients with multiple sclerosis. Twelve patients developed new or increased facial paresthesias after radiosurgery (10%). No patient developed anesthesia dolorosa. There was no other procedural morbidity.

Gamma knife radiosurgery is a minimally invasive technique to treat trigeminal neuralgia. It is associated with a low risk of facial paresthesias, an approximate 80% rate of significant pain relief, and a low recurrence rate in patients who initially attain complete relief. Longer-term evaluations are warranted 13).

References

1)

Brisman R. Gamma knife surgery with a dose fo 75 to 76.8 Gray for trigeminal neuralgia. J Neurosurg. 2004; 100:848–854
2) , 8)

Pollock BE, Phuong LK, Foote RL, Sta ord SL, Gor- man DA. High-dose trigeminal neuralgia radiosur- gery associated with increased risk of trigeminal nerve dysfunction. Neurosurgery. 2001; 49:58–62; discussion 62-4
3)

Kondziolka D, Lunsford LD, Flickinger JC. Stereotactic radiosurgery for the treatment of trigeminal neuralgia. Clin J Pain. 2002; 18:42–47
4)

Massager N, Lorenzoni J, Devriendt D, Desmedt F, Brotchi J, Levivier M. Gamma knife surgery for idi- opathic trigeminal neuralgia performed using a far-anterior cisternal target and a high dose of radiation. J Neurosurg. 2004; 100:597–605
5) , 7)

Urgosik D, Liscak R, Novotny J, Jr, Vymazal J, Vlady- 1982 ka V. Treatment of essential trigeminal neuralgia with gamma knife surgery.JNeurosurg.2005; 102 Suppl:29–33
6)

Maesawa S, Salame C, Flickinger JC, Pirris S, Kond- ziolka D, Lunsford LD. Clinical outcomes after ster- eotactic radiosurgery for idiopathic trigeminal neuralgia. J Neurosurg. 2001; 94:14–20
9)

Ertiaei A, Ataeinezhad Z, Bitaraf M, Sheikhrezaei A, Saberi H. Application of an artificial neural network model for early outcome prediction of gamma knife radiosurgery in patients with trigeminal neuralgia and determining the relative importance of risk factors. Clin Neurol Neurosurg. 2019 Feb 12;179:47-52. doi: 10.1016/j.clineuro.2018.11.007. [Epub ahead of print] PubMed PMID: 30825722.
10)

Régis J, Tuleasca C, Resseguier N, Carron R, Donnet A, Yomo S, Gaudart J, Levivier M. The Very Long-Term Outcome of Radiosurgery for Classical Trigeminal Neuralgia. Stereotact Funct Neurosurg. 2016;94(1):24-32. doi: 10.1159/000443529. Epub 2016 Feb 17. PubMed PMID: 26882097.
11)

Karam SD, Tai A, Wooster M, Rashid A, Chen R, Baig N, Jay A, Harter KW, Randolph-Jackson P, Omogbehin A, Aulisi EF, Jacobson J. Trigeminal neuralgia treatment outcomes following Gamma Knife radiosurgery with a minimum 3-year follow-up. J Radiat Oncol. 2014;3:125-130. Epub 2013 Nov 20. PubMed PMID: 24955219; PubMed Central PMCID: PMC4052001.
12)

Lee JK, Choi HJ, Ko HC, Choi SK, Lim YJ. Long term outcomes of gamma knife radiosurgery for typical trigeminal neuralgia-minimum 5-year follow-up. J Korean Neurosurg Soc. 2012 May;51(5):276-80. doi: 10.3340/jkns.2012.51.5.276. Epub 2012 May 31. PubMed PMID: 22792424; PubMed Central PMCID: PMC3393862.
13)

Kondziolka D, Perez B, Flickinger JC, Habeck M, Lunsford LD. Gamma knife radiosurgery for trigeminal neuralgia: results and expectations. Arch Neurol. 1998 Dec;55(12):1524-9. PubMed PMID: 9865796.

Stereotactic radiosurgery for brain metastases

Stereotactic radiosurgery for brain metastases

Management of brain metastases typically includes radiotherapy (RT) with conventional fractionation and/or stereotactic radiosurgery (SRS). However, optimal indications and practice patterns for SRS remain unclear.

Significant heterogeneity exists in target volumes for postoperative stereotactic radiosurgery.

The use of radiosurgery as a first-line or salvage treatment for brain metastases continues to expand. As a focal, highly precise treatment option, stereotactic radiosurgery (SRS) provides many benefits, including a short treatment timeline, a low probability of normal tissue complication, and a high probability of treated lesion control 1).


Kann et al. sought to evaluate national practice patterns for patients with metastatic disease receiving brain RT. They queried the National Cancer Data Base (NCDB) for patients diagnosed with metastatic non-small cell lung cancer, breast cancer, colorectal cancer, or melanoma from 2004 to 2014 who received upfront brain RT. Patients were divided into SRS and non-SRS cohorts. Patient and facility-level SRS predictors were analyzed with chi-square tests and logistic regression, and uptake trends were approximated with linear regression. Survival by diagnosis year was analyzed with the Kaplan-Meier method. Results: Of 75,953 patients, 12,250 (16.1%) received SRS and 63,703 (83.9%) received non-SRS. From 2004 to 2014, the proportion of patients receiving SRS annually increased (from 9.8% to 25.6%; P<.001), and the proportion of facilities using SRS annually increased (from 31.2% to 50.4%; P<.001). On multivariable analysis, nonwhite race, nonprivate insurance, and residence in lower-income or less-educated regions predicted lower SRS use (P<.05 for each). During the study period, SRS use increased disproportionally among patients with private insurance or who resided in higher-income or higher-educated regions. From 2004 to 2013, 1-year actuarial survival improved from 24.1% to 49.6% for patients selected for SRS and from 21.0% to 26.3% for non-SRS patients (P<.001). Conclusions: This NCDB analysis demonstrates steadily increasing-although modest overall-brain SRS use for patients with metastatic disease in the United States and identifies several progressively widening sociodemographic disparities in the adoption of SRS. Further research is needed to determine the reasons for these worsening disparities and their clinical implications on intracranial control, neurocognitive toxicities, quality of life, and survival for patients with brain metastases 2).

Complications

With increased adoption of this approach also comes an increase in incidence of treatment failure. Radiosurgical failure, either due to tumor regrowth or radiation necrosis, can occur in about 10% to 15% of patients still alive at 1 yr 3).

Radiation necrosis (RN) may occur after treatment and is challenging to distinguish from local recurrence (LR).

PET is superior to computed tomography and magnetic resonance imaging in the differentiation between recurrence and radiation reaction/necrosis. However, temporary radiation effects may mask remaining tumor tissue, and repeat PET studies may sometimes be necessary 4).


There are a variety of salvage options available for patients with brain metastases who experience local failure after stereotactic radiosurgery (SRS). These options include resection,whole brain radiation therapy, laser interstitial thermotherapy, and repeat SRS. There is little data on the safety and efficacy of repeat SRS following local failure of a prior radiosurgical procedure.

Systematic Reviews

2017

Using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using PubMed and Medline up to November 2016. A separate search was conducted for SRS for larger brain metastases.

Twenty-seven prospective study, critical reviews, metaanalysis, and published consensus guidelines were reviewed. Four key points came from these studies. First, there is no detriment to survival by withholding whole brain radiation (WBRT) in the upfront management of brain metastases with SRS. Second, while SRS on its own provides a high rate of local control (LC), WBRT may provide further increase in LC. Next, WBRT does provide distant brain control with less need for salvage therapy. Finally, the addition of WBRT does affect neurocognitive function and quality of life more than SRS alone. For larger brain metastases, surgical resection should be considered, especially when factoring lower LC with single-session radiosurgery. There is emerging data showing good LC and/or decreased toxicity with multisession radiosurgery.

A number of well-conducted prospective and meta-analyses studies demonstrate good LC, without compromising survival, using SRS alone for patients with a limited number of brain metastases. Some also demonstrated less impact on neurocognitive function with SRS alone. Practice guidelines were developed using these data with International Stereotactic Radiosurgery Society consensus 5).


Stereotactic radiosurgery (SRS) offers excellent local control for brain metastases (BM) with low rates of toxicity.

It avoids whole brain radiotherapy (WBRT)-associated morbidity.

Studies have clearly established the safety and efficacy of single-dose SRS. However, as patient survival has increased, the recurrence of tumors and the development of metastases to new sites within the brain have made it desirable to repeat treatments over time. The cumulative toxicity of multi-isocenter, multiple treatments has not been well defined.

Postoperative stereotactic radiosurgery to the resection cavity safely and effectively augments local control of large brain metastases. Patients with <4 metastases and controlled systemic disease have significantly lower rates of distant brain failure (DBF) and are ideal treatment candidates 6).

In patients with limited brain metastases from non small cell lung cancer (NSCLC), SRS is an effective treatment associated with high local control rate with low morbidity. When performed in isolation, close follow-up is mandatory and radiosurgery can be renewed as salvage treatment for distant brain progression, limiting the use of WBRT 7).

Significant tumor volume reduction by 6 or 12 weeks post-SRS was associated with long-term local control.

For patients at low risk of distant intracranial failure (such as those with systemic disease control) with early, robust volumetric response, it may reasonable to lengthen imaging intervals to maximize clinical utility.

Although it is necessary to validate the findings in a larger, prospective series, the results are encouraging that a robust early volumetric response is associated with sustained local control for metastatic brain lesions 8).

Gamma Knife radiosurgery (GKRS) offers a high rate of tumor control and good survival benefits in both new and recurrent patients with MBT. Thus, GKRS is an effective treatment option for new patients with MBT, as well as an adjuvant therapy in patients with recurrent MBT. 9) 10).


There appears to be no consensus regarding the optimal treatment strategy among patients with >3 brain metastases, and practice patterns are heterogeneous. Radiation oncologists, especially high-volume CNS specialists, are treating significantly more brain metastases with SRS than what currently is recommended by published consensus guidelines. Providers struggle with patients with a moderate intracranial disease burden. Further prospective studies are needed to support these practice patterns and guide decision making 11).

Case series

Patients (n = 41) undergoing single-fraction Gamma Knife SRS following surgical resection of brain metastases from 2011 to 2017 were retrospectively reviewed. SRS included the entire contrast-enhancing cavity with heterogeneity in inclusion of the surgical tract and no routine margin along the dura or clinical target volume margin. Follow-up MR imaging was fused with SRS plans to assess patterns of failure.

The median follow-up was 11.1 months with a median prescription of 18 Gy. There were 5 local failures: infield (n = 3, 60%), surgical tract (n = 1, 20%), and marginal > 5 mm from the resection cavity (n = 1, 20%). No marginal failures < 5 mm or dural margin failures were noted. For deep lesions (n = 13), 62% (n = 8) had the entire tract covered. The only tract recurrence was in a deep lesion without coverage of the surgical tract (n = 1/5).

In this small preliminary experience, despite no routine inclusion of the dural tract or bone flap, no failures were noted in these locations. Omission of the surgical tract in deep lesions may increase failure rates 12).

References

1)

Nieder C, Grosu AL, Gaspar LE. Stereotactic radiosurgery (SRS) for brain metastases: a systematic review. Radiat Oncol. 2014 Jul 12;9:155. doi: 10.1186/1748-717X-9-155. Review. PubMed PMID: 25016309; PubMed Central PMCID: PMC4107473.
2)

Kann BH, Park HS, Johnson SB, Chiang VL, Yu JB. Radiosurgery for Brain Metastases: Changing Practice Patterns and Disparities in the United States. J Natl Compr Canc Netw. 2017 Dec;15(12):1494-1502. doi: 10.6004/jnccn.2017.7003. PubMed PMID: 29223987.
3)

Sneed PK, Mendez J, Vemer-van den Hoek JG, Seymour ZA, Ma L, Molinaro AM, Fogh SE, Nakamura JL, McDermott MW. Adverse radiation effect after stereotactic radiosurgery for brain metastases: incidence, time course, and risk factors. J Neurosurg. 2015 Aug;123(2):373-86. doi: 10.3171/2014.10.JNS141610. Epub 2015 May 15. PubMed PMID: 25978710.
4)

Ericson K, Kihlström L, Mogard J, Karlsson B, Lindquist C, Widén L, Collins VP, Stone-Elander S. Positron emission tomography using 18F-fluorodeoxyglucose in patients with stereotactically irradiated brain metastases. Stereotact Funct Neurosurg. 1996;66 Suppl 1:214-24. PubMed PMID: 9032864.
5)

Chao ST, De Salles A, Hayashi M, Levivier M, Ma L, Martinez R, Paddick I, Régis J, Ryu S, Slotman BJ, Sahgal A. Stereotactic Radiosurgery in the Management of Limited (1-4) Brain Metasteses: Systematic Review and International Stereotactic Radiosurgery Society Practice Guideline. Neurosurgery. 2017 Nov 3. doi: 10.1093/neuros/nyx522. [Epub ahead of print] PubMed PMID: 29126142.
6)

Ling DC, Vargo JA, Wegner RE, Flickinger JC, Burton SA, Engh J, Amankulor N, Quinn AE, Ozhasoglu C, Heron DE. Postoperative stereotactic radiosurgery to the resection cavity for large brain metastases: clinical outcomes, predictors of intracranial failure, and implications for optimal patient selection. Neurosurgery. 2015 Feb;76(2):150-7. doi: 10.1227/NEU.0000000000000584. PubMed PMID: 25549189.
7)

Zairi F, Ouammou Y, Le Rhun E, Aboukais R, Blond S, Vermandel M, Deken V, Devos P, Reyns N. Relevance of gamma knife radiosurgery alone for the treatment of non-small cell lung cancer brain metastases. Clin Neurol Neurosurg. 2014 Oct;125:87-93. doi: 10.1016/j.clineuro.2014.07.030. Epub 2014 Jul 27. PubMed PMID: 25108698.
8)

Sharpton SR, Oermann EK, Moore DT, Schreiber E, Hoffman R, Morris DE, Ewend MG. The Volumetric Response of Brain Metastases After Stereotactic Radiosurgery and Its Post-treatment Implications. Neurosurgery. 2014 Jan;74(1):9-16. doi: 10.1227/NEU.0000000000000190. PubMed PMID: 24077581.
9)

Bir SC, Ambekar S, Nanda A. Long term outcome of Gamma Knife radiosurgery for metastatic brain tumors. J Clin Neurosci. 2014 Dec;21(12):2122-8. doi: 10.1016/j.jocn.2014.05.015. Epub 2014 Jul 25. PubMed PMID: 25065951.
10)

Bir SC, Ambekar S, Bollam P, Nanda A. Long-term outcome of gamma knife radiosurgery for metastatic brain tumors originating from lung cancer. Surg Neurol Int. 2014 Sep 5;5(Suppl 8):S396-403. doi: 10.4103/2152-7806.140197. eCollection 2014. PubMed PMID: 25289169; PubMed Central PMCID: PMC4173307.
11)

Sandler KA, Shaverdian N, Cook RR, Kishan AU, King CR, Yang I, Steinberg ML, Lee P. Treatment trends for patients with brain metastases: Does practice reflect the data? Cancer. 2017 Feb 8. doi: 10.1002/cncr.30607. [Epub ahead of print] PubMed PMID: 28178376.
12)

McDermott DM, Hack JD, Cifarelli CP, Vargo JA. Tumor Cavity Recurrence after Stereotactic Radiosurgery of Surgically Resected Brain Metastases: Implication of Deviations from Contouring Guidelines. Stereotact Funct Neurosurg. 2019 Feb 14:1-7. doi: 10.1159/000496156. [Epub ahead of print] PubMed PMID: 30763944.

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 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

The exact mechanism of pain relief after radiosurgery is not clearly understood. Histopathology examination of the trigeminal nerve in humans after radiosurgery is rarely performed and has produced controversial results.

There is evidence of histological damage of the trigeminal nerve fibers after radiosurgery therapy. Whether or not the presence and degree of nerve damage correlate with the degree of clinical benefit and side effects are not revealed and need to be explored in future studies 3).

Existing studies leave important doubts as to optimal treatment doses or the therapeutic target, long-term recurrence, and do not help identify which subgroups of patients could most benefit from this technique 4).

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% 5) 6) 7) 8) but only ≈ 65% become pain free. Median latency to pain relief: 3 months (range: 1 d-13 months) 9).

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

Favorable prognosticators: higher radiation doses, previously unoperated patient, absence of atypical pain component, normal pre-treatment sensory function 10).

Side effects: Hypesthesia occurred in 20% after initial SRS, and in 32% of those requiring repeat treatment 11) (higher rates associated with higher radiation doses) 12).

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 13).

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 14).


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 15).

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)

Al-Otaibi F, Alhindi H, Alhebshi A, Albloushi M, Baeesa S, Hodaie M. Histopathological effects of radiosurgery on a human trigeminal nerve. Surg Neurol Int. 2014 Jan 18;4(Suppl 6):S462-7. doi: 10.4103/2152-7806.125463. eCollection 2013. PubMed PMID: 24605252.
4)

Varela-Lema L, Lopez-Garcia M, Maceira-Rozas M, Munoz-Garzon V. Linear Accelerator Stereotactic Radiosurgery for Trigeminal Neuralgia. Pain Physician. 2015 Jan-Feb;18(1):15-27. PubMed PMID: 25675056.
5)

Brisman R. Gamma knife surgery with a dose fo 75 to 76.8 Gray for trigeminal neuralgia. J Neurosurg. 2004; 100:848–854
6)

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
7) , 12)

Kondziolka D, Lunsford LD, Flickinger JC. Stereotact ic radiosurgery for the treatment of trigeminal neuralgia. Clin J Pain. 2002; 18:42–47
8)

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
9) , 11)

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
10)

Maesawa S, Salame C, Flickinger JC, Pirris S, Kondziolka D, Lunsford LD. Clinical outcomes after stereotactic radiosurgery for idiopathic trigeminal neuralgia. J Neurosurg. 2001; 94:14–20
13)

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.
14)

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.
15)

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.
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