Radiofrequency Ablation For Chronic Migraine – A Randomized Controlled Trial

Introduction: Migraine is a common form of primary neurologic headache.1,2 It’s a chronic relapsing relenting disease resulting in many functional years lost in disability. This condition is generally treated with drugs. However 30% of the patients are refractory to drugs.3 When the condition becomes chronic or refractory to medical treatment or associated with side effects of it, surgery is indicated.4,5 The benefit of surgical treatment varies from 65-90% for chronic migraine.6 We have demonstrated that peripheral neurectomy of trigeminal nerves is safe and effective for appropriately selected migraine patients.5,7 This surgery however is associated with a scar postoperatively which many patients are reluctant for. Radiofrequency ablation (RFA) is a percutaneous technique for neural ablation. It is a safe and effective technique for many neurological conditions including headaches due to migraine and other causes.8–10 The RFA gives pain relief in 80-90% patients with average relief in range of 60-70%.10 The benefits include a day-care procedure with lack of any stich or scar. The literature regarding drug reduction / dosage reduction for prophylactic antimigraine therapy is sparse with RFA. Also there is no randomized controlled trial on RFA for chronic migraine at present.

Aim: To evaluate the surgical and functional outcomes of radiofrequency ablation for chronic migraine

Objectives:

Primary: To study the pain outcomes of RF ablation for migraine using Visual analog score and migraine headache index

Secondary: To study the functional outcomes of RF ablation for migraine using Migraine disability assessment test (MIDAS score) and Pain self-efficacy questionnaire (PSEQ).

                       Justification: Surgical intervention can lead to cure of the migraine, and will add many functional years to the patient’s life. It will also be cost effective compared to the chronic drug treatment of the

migraine.

Methodology

Study design: The study will be a randomized controlled trial to be done in Superspeciality Hospital, NSCB Govt. Medical College, Jabalpur

Inclusion criteria:

1.     Patients with chronic or drug refractory migraine

2.     Patients who had >50% relief with local anesthetic block (0.5% Bupivacaine).

 Exclusion criteria:

1.     Patient refusal

 Subject recruitment:

Total 86 patients will be recruited from the neurology and neurosurgery OPD and wards, who will be randomized into test and control arm based on 1:1 ratio.

 Intervention of subjects

Surgical protocol: The trigger site will be confirmed using a preoperative local anesthetic (Bupivacaine block). Thereafter, under local anesthesia (Bupivacaine) with SOS midazolam 1mg, patients will be given sensory and motor stimulation using radiofrequency probe. It will be inserted through a 20/22 gauge needle with 4mm active tip. The sensory stimulation will confirm the site of pain. The motor stimulation should give negative effect. The test arm will undergo RF ablation using 70-80 degrees Celsius for 60-180 seconds. The control arm will undergo a sham ablation. For the frontal headaches, supraorbital and supratrochlear nerves will be targeted, for temporal headaches the Zygomaticotemporal and/or Auriculotemporal nerves will be targeted, and for occipital and cervicogenic headaches the greater and/or lesser occipital nerves will be ablated. Postoperatively, patients will be monitored in neurosurgery ward and will be discharged thereafter.

 Assessment: Patients will be assessed as per the attached proforma.

 Blinding: Both patients and assessing neurologist will be blinded in which group the patient was placed in.

 Post-intervention management: Based on the effect of intervention neurologist will have the freedom to continue or abort the abortive and prophylactic treatment of migraine.

 Patient evaluation:

Patients will be evaluated as shown in the proforma attached. The follow-up period will be minimum 6 months.

 Patient proforma

Demographics

S.No.

Age:

Gender:

Duration of illness (in months):

Trigger sites (Frontal, temporal, occipital):

Provoking factor:

Brain imaging done (yes/no):                                         Any incidental finding:

VAS Score of pain before surgery:

PSEQ score before surgery:

Migraine headache index (intensity x frequency x duration) before surgery:

Number of abortive drugs:                                                         Whether relieved with drugs:

Number of prophylactic drugs:                                                   Whether relieved with drugs:

Palpable pulse at pain site:

Unilateral/bilateral:

Side (Left/Right):

Percent benefit with local anesthetic (in %):

 Surgical factors

Date of operation:

Which nerve:

Which arm (test/control):

No. of ablations:

Temperature/s used:

Duration of surgery:

Intraoperative pain (in a scale of 1 to 10):

Relief in percentage:

Complications:

 Follow-up at 7 days

VAS score:

MIDAS score:

PSEQ score:

Migraine headache index (intensity x frequency x duration):

Subjective improvement in percentage:

Complications:

Number of abortive drugs:                                                         Whether relieved with drugs:

Number of prophylactic drugs:                                                   Whether relieved with drugs:

  Follow-up at 1 month

VAS score:

MIDAS score:

PSEQ score:

Migraine headache index (intensity x frequency x duration):

Subjective improvement in percentage:

Complications:

Number of abortive drugs:                                                         Whether relieved with drugs:

Number of prophylactic drugs:                                                   Whether relieved with drugs:

 Follow-up at 3 month

VAS score:

MIDAS score

PSEQ score:

Migraine headache index (intensity x frequency x duration):

Subjective improvement in percentage:

Complications:

Number of abortive drugs:                                                         Whether relieved with drugs:

Number of prophylactic drugs:                                                   Whether relieved with drugs:

 Follow-up at 6 month

VAS score:

MIDAS score:

PSEQ score:

Migraine headache index (intensity x frequency x duration):

Subjective improvement in percentage:

Complications:

Number of abortive drugs:                                                         Whether relieved with drugs:

Number of prophylactic drugs:                                                   Whether relieved with drugs:

 Follow-up at 12 months

VAS score:

MIDAS score:

PSEQ score:

Migraine headache index (intensity x frequency x duration):

Subjective improvement in percentage:

Complications:

Number of abortive drugs:                                                         Whether relieved with drugs:

Number of prophylactic drugs:                                                   Whether relieved with drugs:

 Sample size: Taking the benefit of RFA for chronic migraine to be about 62%,10 and placebo effect to be about 30%,11 the sample size came to be 39 in each arm using the Kelsey method.12 Taking about 10% drop down, a minimum sample size of 43 will be in each arm.

  Statistical analysis: Data will be recorded in a Microsoft excel sheet and will be analyzed using SPSS 22.0 software for evaluating the safety and efficacy of the procedure.

 Safety: The procedure is normally safe as it is done in the subcutaneous tissues.

National significance: The study can be a landmark one for our country. It will help in reducing the suffering of many patients, adding useful functional years to their lives, and reducing the cost of medicines.