Analysis Of Factors Predicting For Pain Resolution After Gamma Knife Radiosurgery For Medically Refractory Trigeminal NeuralgiaKeywords: trigeminal neuralgia, pain, gamma knife, outcome, cranial nerveInteractive Manuscript
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What is the background behind your study?
What is the purpose of your study?
To evaluate the clinical outcomes of patients undergoing Gamma Knife (GK) stereotactic radiosurgery as a non-surgical treatment for trigeminal neuralgia (TGN).
Describe your patient group.
Ninety-five patients underwent GK for TGN between 12/2006 and 6/2009 at William Beaumont Hospital. Eighty had follow-up > 6 weeks and were the subject of this report. Median patient age was 68 years (50-92); 58 female, 22 male. 74% of patients had typical trigeminal pain, 11% had atypical features and 11% multiple sclerosis. Thirty patients (38%) had undergone prior surgical procedures and 37 (46%) had pre-existing sensory complaints.
Describe what you did.
The median dose delivered was 40 Gy (range: 35-45 Gy) at the 50% isodose line using either a single (85%) or two (6%) isocenters with the 4 mm diameter collimator, or two isocenters with a 4 mm and 8 mm collimator helmet (9%). Patients were seen within 2 weeks post-GK and then every 3-6 months in addition to periodic mail surveys and telephone interviews. Multiple patient and treatment-related factors were analyzed for association with pain relief. Mean follow-up duration was 14.7 months.
Describe your main findings.
91% of patients (n=73) reported at least partial pain resolution: 45% (n=36) complete pain relief, 46% (n=37) partial relief. The median time to pain resolution was 23 days. Seventeen patients (23%) who had partial to complete resolution had pain recurrence (median: 6.3 months). The pain recurrence rate was higher in patients with MS (44% versus 20%). Sixteen (20%) patients reported new post-treatment sensory complaints; no other complications were noted. We identified that the greater the treated nerve length, the greater the probability of achieving BNI of I-II (p=0.021) and for resolution to be experienced (p=0.037). The cut-point length for partial/complete relief was a treated length of 0.51cm.
Describe the main limitation of this study.
This is a retrospective study.
Describe your main conclusion.
In this study, GK radiosurgery for trigeminal neuralgia was associated with complete or partial pain resolution in 91% of patients. Longer treated nerve length was associated with better pain resolution.
Describe the importance of your findings and how they can be used by others.
Although 23% of patients had pain recurrence after GK, the initial success and recurrence rates appear similar to those reported after percutaneous treatment approaches with minimal post-treatment neurological complaints. Additional follow-up will be required to assess the durability of relief.
To evaluate the clinical outcomes of patients undergoing Gamma Knife (GK) stereotactic radiosurgery as a non-surgical treatment for trigeminal neuralgia (TGN).
Ninety-five patients underwent GK for TGN between 12/2006 and 6/2009 at William Beaumont Hospital. Eighty had follow-up > 6 weeks and were the subject of this report. Median patient age was 68 years (50-92); 58 female, 22 male. 74% of patients had typical trigeminal pain, 11% had atypical features and 11% multiple sclerosis. Thirty patients (38%) had undergone prior surgical procedures and 37 (46%) had pre-existing sensory complaints.
The median dose delivered was 40 Gy (range: 35-45 Gy) at the 50% isodose line using either a single (85%) or two (6%) isocenters with the 4 mm diameter collimator, or two isocenters with a 4 mm and 8 mm collimator helmet (9%). Patients were seen within 2 weeks post-GK and then every 3-6 months in addition to periodic mail surveys and telephone interviews. Multiple patient and treatment-related factors were analyzed for association with pain relief. Mean follow-up duration was 14.7 months.
91% of patients (n=73) reported at least partial pain resolution: 45% (n=36) complete pain relief, 46% (n=37) partial relief. The median time to pain resolution was 23 days. Seventeen patients (23%) who had partial to complete resolution had pain recurrence (median: 6.3 months). The pain recurrence rate was higher in patients with MS (44% versus 20%). Sixteen (20%) patients reported new post-treatment sensory complaints; no other complications were noted. We identified that the greater the treated nerve length, the greater the probability of achieving BNI of I-II (p=0.021) and for resolution to be experienced (p=0.037). The cut-point length for partial/complete relief was a treated length of 0.51cm.
This is a retrospective study.
In this study, GK radiosurgery for trigeminal neuralgia was associated with complete or partial pain resolution in 91% of patients. Longer treated nerve length was associated with better pain resolution.
Although 23% of patients had pain recurrence after GK, the initial success and recurrence rates appear similar to those reported after percutaneous treatment approaches with minimal post-treatment neurological complaints. Additional follow-up will be required to assess the durability of relief.
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