**5. Results**

In 2000, Guyuron was the first to show in a retrospective study the relation between MH and corrugator supercilii muscle resection when he reported that 80% of patients described eliminationorimprovementintheirheadaches followingcorrugator superciliimuscle avulsion forforeheadrejuvenationsurgery [4].This evidence was followedby aprospective study where he reported a 95% rate of either complete alleviation or improvement in MH after a mean follow-up of 1 year [5]. Over the last 15 years, Guyuron conducted several anatomical and clinical studies reporting a reduction of the frequency, duration, and intensity of MH by at least half in 80–90% of patients [4–10]. In 2011, Guyuron et al. published a study examining the longterm benefits of migraine surgery where it was reported an 88% success rate after a 5-year follow-up (29% completely healed; 59% gained improvement; 12% did not show any change) [8]. Other independent groups reported similar findings using Guyuron's protocols, demonstrating the effectiveness of the procedure and the reproducibility of the results [5, 12–15].

From June 2011 till February 2016, we have performed MH decompression surgery over 89 patients with either frontal, occipital, or temporal migraine trigger sites. After a mean followup of 17 months (range: 3–56 months), 93.9% of patients reported positive response to surgery, 52.4% had complete elimination of their migraine, while 41.5% referred at least a 50% reduction in MH symptoms, and 6.1% of patients did not notice any improvement after the surgery. Patients with frontal migraine trigger site reported a 94% positive response to surgery (32% complete relief and 62% significant improvement), 6% had no change in their symptoms, while patients with occipital migraine had positive response in 93.7% (85.5% complete relief and 8.2% significant improvement), and 6.3% did not get any better. Patients complaining for temporal MH had 83.3% positive surgical outcome (50% complete MH elimination, 33.3 significant improvement), and 16.7% of patients did not notice any improvement.

Overall response rates are almost the same as no significant differences can be found between the trigger sites. However, occipital migraine surgery leads to higher rates of complete relief of symptoms than the frontal and temporal and intranasal ones (85.5 vs. 32, 50, and 34%, respectively). This may be attributable to a more complete and thorough decompression since the fourth- and sixth-site surgeries are technically easier to perform.

All patients continue to experience a quality of life better than before surgery, and all would have the surgery again.

As reported in literature, we do have patients that reported complete relief during the first 30– 60 days postoperatively and then gradual (though improved) return of symptoms to the treated region [5, 6, 9]. This event was most common with frontal migraine. The recurrent headaches were often described as less intense and more "treatable," and improvement were beyond baseline. These events were very disappointing for both the surgeon and the patients; no exact mechanism has been found, but it seemed to coincide directly with returning nerve function.

Furthermore, patients should be informed when signing the informed consent that deactivation of a MH trigger site may unmask secondary headaches in almost 17.8% of patients and

In 2000, Guyuron was the first to show in a retrospective study the relation between MH and corrugator supercilii muscle resection when he reported that 80% of patients described eliminationorimprovementintheirheadaches followingcorrugator superciliimuscle avulsion forforeheadrejuvenationsurgery [4].This evidence was followedby aprospective study where he reported a 95% rate of either complete alleviation or improvement in MH after a mean follow-up of 1 year [5]. Over the last 15 years, Guyuron conducted several anatomical and clinical studies reporting a reduction of the frequency, duration, and intensity of MH by at least half in 80–90% of patients [4–10]. In 2011, Guyuron et al. published a study examining the longterm benefits of migraine surgery where it was reported an 88% success rate after a 5-year follow-up (29% completely healed; 59% gained improvement; 12% did not show any change) [8]. Other independent groups reported similar findings using Guyuron's protocols, demonstrating the effectiveness of the procedure and the reproducibility of the results [5, 12–15].

From June 2011 till February 2016, we have performed MH decompression surgery over 89 patients with either frontal, occipital, or temporal migraine trigger sites. After a mean followup of 17 months (range: 3–56 months), 93.9% of patients reported positive response to surgery, 52.4% had complete elimination of their migraine, while 41.5% referred at least a 50% reduction in MH symptoms, and 6.1% of patients did not notice any improvement after the surgery. Patients with frontal migraine trigger site reported a 94% positive response to surgery (32% complete relief and 62% significant improvement), 6% had no change in their symptoms, while patients with occipital migraine had positive response in 93.7% (85.5% complete relief and 8.2% significant improvement), and 6.3% did not get any better. Patients complaining for temporal MH had 83.3% positive surgical outcome (50% complete MH elimination, 33.3

significant improvement), and 16.7% of patients did not notice any improvement.

the fourth- and sixth-site surgeries are technically easier to perform.

have the surgery again.

Overall response rates are almost the same as no significant differences can be found between the trigger sites. However, occipital migraine surgery leads to higher rates of complete relief of symptoms than the frontal and temporal and intranasal ones (85.5 vs. 32, 50, and 34%, respectively). This may be attributable to a more complete and thorough decompression since

All patients continue to experience a quality of life better than before surgery, and all would

As reported in literature, we do have patients that reported complete relief during the first 30– 60 days postoperatively and then gradual (though improved) return of symptoms to the treated region [5, 6, 9]. This event was most common with frontal migraine. The recurrent headaches were often described as less intense and more "treatable," and improvement were

that more than one surgery may be needed [9].

110 Current Perspectives on Less-known Aspects of Headache

**5. Results**

Average frequency, intensity, and duration of migraine headache significantly improve. The mean number of days lost from work usually reduces by four times.

Since surgical deactivation of peripheral sensory nerves has demonstrated to be effective for the treatment of MH, positive surgical outcome also has significant economic value as it leads to cost savings by cutting expenses associated with medications, doctor visits, and other financial burdens relating to migraine headache [2]. The median total cost for MH treatment drops from \$5,820/year preoperatively to \$900/year postoperatively with a total median cost reduction of \$3,949.70/year postoperatively [2]. Surgery has a mean cost of \$8,378; thus, MH surgery is cost-effective, reducing both direct and indirect cost; it has also essential social effects by improving the working performances and increasing the participation in daily living activities.

Our results are similar to those reported in literature by other authors [3, 6, 8, 9]. Global positive response rates did not show any significant differences, ranging between 80 and 95%; frontal MH is the most frequent one, but it's also the one that more often either recurred or unmasked a second trigger site after decompression surgery [8, 9]. Occipital MH instead has the better surgical outcome with the highest resolution rate [6, 8].

We believe that this difference may be caused by the compression of the dilated occipital vessels, which is often observed during the surgery and, once removed, lowers the risk for recurrence. Compression over frontal and temporal trigger site is usually consequent to muscular impingement; thus scar tissue might connect again the divided muscular fibers recreating some kind of nerve compression.

Elimination rate of frontal migraine has the highest variability, performed either by endoscopic or transpalpebral approach. Poggi reported a 16.7% complete elimination rate of frontal MH, Guyuron described a 57.1 resolution rate, while Janis gained complete relief of frontal MH only in 8.7% of patients [5]. This discrepancy may partially be explained by variation in the technique: Guyuron and Poggi performed the frontal glabellar muscle avulsion, while Janis resected the only corrugator [5, 6]. Bearden and coworkers reported 58% complete relief of frontal MH following transpalpebral corrugator muscle resection [5]. We have reported a 32% resolution of frontal MH by means of endoscopic resection of glabellar muscles. Thus, complete avulsion of procerus, corrugator, and depressor supercilii muscles may lead to higher elimination rate, but no clear evidences have been reported.

Complete resection of the glabellar muscles can be easily obtained thanks to the magnification offered by the endoscopic technique, which provides a better means to preserve the nerves, resect the muscles, and identify secondary nerve branches [12–15]. Nevertheless, patients that undergo transpalpebral access surgery may experience higher rate of complication (e.g., risk for intraoperative bleeding, more noticeable scars) and a more invasive procedure than if it would have been performed endoscopically; furthermore, patients show lower compliance to receive an open surgery. Therefore, we agree with the common belief that the endoscopic approach for frontal migraine therapy should be considered as the first choice since it has been demonstrated that odds ratio for improvement or elimination is higher if compared with the transpalpebral access [4–6, 12–15]. Trans-palpebral nerve decompression should be performed when a forehead length of 8 cm or more contraindicates the endoscopic approach.

Chepla and coworker showed that patients presenting supraorbital foramen instead of the supraorbital notch experienced higher success rate after resection of the glabellar muscle group with foraminotomy, thus supporting the hypothesis that the supraorbital nerve may be constricted within the foramen leading to frontal migraine headaches [5].

Furthermore, it emerged that some factors may affect the surgical outcome. Migraine surgery failure seems to be associated with increased intraoperative bleeding, surgery on fewer trigger sites, and history of significant head and neck trauma, while older age of migraine onset, higher rate of visual symptoms, surgery at Site I or II, and deactivating all four operative sites are associated with migraine surgery success [5, 8, 9]. The exact relationship between history of head and neck trauma, age of onset, visual symptoms, and response to surgery is not understood. Patients complaining multiple trigger sites will undergo multiple decompression surgeries addressing even minor triggers; this is likely the explanation for better outcome associated with greater number of operative locations. Intraoperative bleeding may interfere with optimal surgical outcome by promoting scar tissue formation. Intraoperative bleeding and blood pressure must be controlled aggressively in order maximize success rate. MH characteristics (e.g., frequency, duration, and amount of drugs needed) also seem to affect the surgical outcome; milder MH have higher chances of improvement in comparison to more severe ones, which are more likely to recur postoperatively [5, 8, 9]. Preliminary Botox infiltration does not affect the surgical success [10].
