**3. Surgical treatment of migraine**

#### **3.1. Frontal trigger site**

Initially, patients who suffered from frontal migraine headache due to muscle compression underwent a procedure developed by Guyuron et al., in which hyperexcitability and inflammation of supraorbital and supratrochlear nerves were eliminated through selective myotomies of depressor supercilii, corrugator supercilii, and procerus muscles, using a transpalpebral approach. The frontal trigger site was approached by means of incising the supratarsal crease involving up to two-thirds of the medial limit of the caudal portion of the conventional upper blepharoplasty incision. After, a skin-orbicularis oculi muscle flap was raised above the level of the septum and the orbicularis muscle in a cephalic direction. The depressor supercilii muscle was exposed and resected as completely as possible, protecting the supraorbital nerve and supratrochlear nerve to allow exposure of the corrugator supercilii muscle. After excision with electrocautery of the corrugator supercilii, lateral fibers of the procerus muscle encasing the supratrochlear nerve were also removed. Fat was then harvested either from the medial fat pad of the upper lid or from an area deep to the deep temporal fascia above the zygomatic arch, if endoscopic ablation of the zygomaticotemporal branch of the trigeminal nerve was performed concomitantly, and placed to fill the depression left following

**Figure 1.** The endoscope is inserted through one incision in the subgaleal plane until the superciliary region is reached to perform the section of the corrugator supercilii, depressor supercilii, and procerus muscles (this picture belongs to Prof. Edoardo Raposio).

resection of the corrugator supercilii muscle and to cushion the nerves [6–8]. The supraorbital nerve, a sensory branch of the ophthalmic division of the trigeminal nerve, exits the orbit by passing over the supraorbital ridge or via a notch or foramen before diving into a superficial and deep branch and is intimately related to the corrugator supercilii in 78% of patients. While incomplete resection of the glabellar muscle group may account for persistent migraine in some patients, the supraorbital foramen (present in 25% of patients) may represent an additional compression site. Since 2002 Guyuron has performed a supraorbital foraminotomy during release of the supraorbital nerve if encountered during resection of the corrugator. As regards the effectiveness of transpalpebral nerve decompression in contrast with the endoscopic approach, a transpalpebral approach did not allow myotomies to be complete, failing to remove more than one-third of the corrugator supercilii muscle transverse portion. The whole corrugator supercilii muscle might be removed by means of an endoscopic approach, which was thus claimed to be more thorough and appropriate for this purpose. Endoscopic nerve decompression, however, was not performed on patients with long foreheads (8 cm measured from the anterior hairline to the supraorbital ridge) or on patients with significant curvature to the forehead, as endoscopic access would have been difficult to impossible. It relies on three to six access incisions 1.5–2 cm in length, located 1–2 cm behind the anterior hairline. Two distinct surgical instruments, an endoscope and a dissector, are generally used. In an effort to reduce the invasiveness of the current endoscopic techniques, we described our minimally invasive, endoscopic selective myotomy technique with a single access, performed with a specifically modified endoscope (Karl Storz, Tuttlingen, Germany) and without the need for general anesthesia [12–15]. With the patient supine and the head in a neutral position, frontal trigger nerves are located. Skin markings are drawn above the eyebrow bilaterally, at the mid-pupillary line (supraorbital nerve) and 1 cm medially (supratrochlear nerve). In this minimally invasive technique for forehead headache treatment, local anesthesia with diluted 40-cc Carbocaine 1% + 40-cc NaCl 0.9% and 20-cc sodium bicarbonate 8.4% is injected in the forehead, between the glabellar region and about 2 cm behind the anterior hairline. The infiltration of local anesthetic allows not only anesthesia but also the undermining of the tissues and the creation of a space between the periosteum and adjacent tissues to facilitate endoscopic visualization. A single 1.5-cm incision is then performed on the midline, 1 cm behind the frontal hairline. All tissues are dissected (cutaneous, subcutaneous, aponeurotic galea) until the periosteum is reached in the subgaleal plane. This location is chosen so that the postoperative scar will be hidden in the patient's hair. Tissues all over the forehead bilaterally are undermined in the subgaleal plane through the hairline incision by means of long scissors. Undermining must be done carefully, particularly when the inferior limit of the undermining area (superciliary region) is reached, in order not to damage supratrochlear and supraorbital nerves. The lateral anatomic limit of the undermining area is the temporal region, bilaterally. In order to lift the frontal skin during the endoscopic procedure and better visualize the anatomic structures, nylon 1-0 sutures are placed in the superciliary region at each side of both supratrochlear and supraorbital nerves bilaterally. Then a suction of blood and residual anesthetic fluid in the entire undermined forehead is performed through the hairline incision before inserting the endoscope and whenever the endoscopic view is not clear. Our modified endoscope (Karl Storz, Tuttlingen, Germany) consists of a 9-mm trocar with an air/insufflator/

the semispinalis. It then exits the overlying trapezius muscle or the fasci, emerging in an area 4 cm in diameter centered 1.3 cm from midline and 6.2 cm below the line between the two

Initially, patients who suffered from frontal migraine headache due to muscle compression underwent a procedure developed by Guyuron et al., in which hyperexcitability and inflammation of supraorbital and supratrochlear nerves were eliminated through selective myotomies of depressor supercilii, corrugator supercilii, and procerus muscles, using a transpalpebral approach. The frontal trigger site was approached by means of incising the supratarsal crease involving up to two-thirds of the medial limit of the caudal portion of the conventional upper blepharoplasty incision. After, a skin-orbicularis oculi muscle flap was raised above the level of the septum and the orbicularis muscle in a cephalic direction. The depressor supercilii muscle was exposed and resected as completely as possible, protecting the supraorbital nerve and supratrochlear nerve to allow exposure of the corrugator supercilii muscle. After excision with electrocautery of the corrugator supercilii, lateral fibers of the procerus muscle encasing the supratrochlear nerve were also removed. Fat was then harvested either from the medial fat pad of the upper lid or from an area deep to the deep temporal fascia above the zygomatic arch, if endoscopic ablation of the zygomaticotemporal branch of the trigeminal nerve was performed concomitantly, and placed to fill the depression left following

**Figure 1.** The endoscope is inserted through one incision in the subgaleal plane until the superciliary region is reached to perform the section of the corrugator supercilii, depressor supercilii, and procerus muscles (this picture belongs to

external auditory canals [3, 5, 6, 11].

102 Current Perspectives on Less-known Aspects of Headache

**3.1. Frontal trigger site**

Prof. Edoardo Raposio).

**3. Surgical treatment of migraine**

suction triple valve, a straight Hopkins telescope with fiber-light transmission, a Wittmöser operating sheath with a connection for high-frequency diathermy, and a specifically designed elliptical-tipped wire loop electrode for electrocautery. The modified endoscope is inserted through the incision in the subgaleal plane (**Figure 1**) and used to perform endoscopically assisted section of the corrugator supercilii, depressor supercilii, and procerus muscles bilaterally (**Figure 2**), with the purpose of decompressing the supraorbital nerve and supratrochlear nerves bilaterally. During this procedure, it is important to dissect every part of the muscle, which receives facial nerve fibers responsible for contraction of the muscle itself, in order to prevent irritation to surrounding nerves from the muscle's movement. At the end of the procedure, after an accurate hemostasis, the cutaneous access is closed with absorbable suture, without any drainage, and a compressive bandage is positioned all around the patient's head.

**Figure 2.** Endoscopically assisted section of the corrugator supercilii and depressor supercilii muscles (this picture belongs to Prof. Edoardo Raposio).

#### **3.2. Temporal trigger site**

The zygomaticotemporal branch of the trigeminal nerve travels between the temporalis muscle and the lateral orbital wall and is commonly transected during craniofacial or esthetic forehead surgery, with no reported consequence. Transcutaneous tattooing of the nerve site by the measurement from the lateral canthus (17 mm lateral and 6.5 mm cephalad to the lateral canthus) could be used to forewarn the surgeon about the location of the nerve. Under local anesthesia two incisions measuring 1.5 cm are made on each side located approximately 7 and 10 cm from the midline. Dissection under the incisions is realized by scissors to expose the deep temporal fascia and with a periosteal elevator is conducted medially, laterally, cephalad, and caudally to accommodate the endoscope. To reach this nerve safely, it is crucial to identify the deep temporal fascia beneath the scalp incision and to continue the dissection in this plane. The zygomaticotemporal branch of the trigeminal nerve is then exposed, isolated, and avulsed on one side, removing approximately 2.5 cm of the nerve, while on the other side, it is decompressed by widening the fascia opening and removing the zygomaticotemporal artery. The proximal nerve end is allowed to retract into temporalis muscle to reduce the risk of neuroma formation. Some surgeons prefer to locate the zygomaticotemporal branch of the trigeminal nerve through a transpalpebral incision [5, 6]. A careful dissection along the inferior lateral orbital rim over the deep temporal fascia is performed. The superficial temporal fascia is carefully lifted off the deep temporal fascia with an elevator and a lighted retractor to retract the tissue and protect the sentinel vein and the temporal branch of the facial nerve. Careful dissection around the vein to identify the zygomaticotemporal nerve is performed, and once identified, the zygomaticotemporal nerve is avulsed. Both avulsion neurectomy and decompression of the zygomaticotemporal branch of the trigeminal nerve are equally effective methods for the treatment of temporal migraine headache, but decompression is the first option. The avulsion remains a logical alternative when decompression is technically difficult or when the zygomaticotemporal branch of the trigeminal nerve has multiple branches without concomitant vessels or tight fascia bands. Our experience about surgical treatment of temporal migraine concerns on open decompression of the zygomaticotemporal branch of trigeminal nerve. In the first moment, the patient indicates the trigger point in temporal region, after we inject local anesthetic and we make a 3-cm cutaneous incision in the same area. By the blunt tip scissors, we perform the dissection up to the deep temporal fascia. We open the inferior temporal septum keeping above the fascia to expose the inferior temporal compartment that contains the zygomaticotemporal nerve, sentinel vessels, and temporal branches of facial nerve. After operating this septum, it is imperative that the level of dissection hug the floor of the space, that is, directly on the deep temporal fascia, because the temporal branches of facial nerve course through the roof of the lower temporal compartment immediately abutting the inferior temporal septum. Then we perform the zygomaticotemporal nerve decompression realizing it from constricting temporal muscle fibers, without any avulsion. When the patient describes a pulsing pain in the temporal region, we perform the electrocautery of sentinel vessels. Eventually, the cutaneous access is closed with absorbable suture, and a compressive bandage is positioned all around the patient's head.

#### **3.3. Occipital trigger site**

suction triple valve, a straight Hopkins telescope with fiber-light transmission, a Wittmöser operating sheath with a connection for high-frequency diathermy, and a specifically designed elliptical-tipped wire loop electrode for electrocautery. The modified endoscope is inserted through the incision in the subgaleal plane (**Figure 1**) and used to perform endoscopically assisted section of the corrugator supercilii, depressor supercilii, and procerus muscles bilaterally (**Figure 2**), with the purpose of decompressing the supraorbital nerve and supratrochlear nerves bilaterally. During this procedure, it is important to dissect every part of the muscle, which receives facial nerve fibers responsible for contraction of the muscle itself, in order to prevent irritation to surrounding nerves from the muscle's movement. At the end of the procedure, after an accurate hemostasis, the cutaneous access is closed with absorbable suture, without any drainage, and a compressive bandage is positioned all around the patient's

**Figure 2.** Endoscopically assisted section of the corrugator supercilii and depressor supercilii muscles (this picture be-

The zygomaticotemporal branch of the trigeminal nerve travels between the temporalis muscle and the lateral orbital wall and is commonly transected during craniofacial or esthetic forehead surgery, with no reported consequence. Transcutaneous tattooing of the nerve site by the measurement from the lateral canthus (17 mm lateral and 6.5 mm cephalad to the lateral canthus) could be used to forewarn the surgeon about the location of the nerve. Under local anesthesia two incisions measuring 1.5 cm are made on each side located approximately 7 and 10 cm from the midline. Dissection under the incisions is realized by scissors to expose the deep temporal fascia and with a periosteal elevator is conducted medially, laterally, cephalad, and caudally to accommodate the endoscope. To reach this nerve safely, it is crucial to identify the deep temporal fascia beneath the scalp incision and to continue the dissection in this plane. The zygomaticotemporal branch of the trigeminal nerve is then exposed, isolated, and avulsed

head.

104 Current Perspectives on Less-known Aspects of Headache

longs to Prof. Edoardo Raposio).

**3.2. Temporal trigger site**

The purpose of the surgical treatment of Site IV is to remove the potential compression points of the greater occipital nerve along its course throughout the semispinalis and the trapezius muscles to the subcutaneous tissue of the occipital scalp. The avulsion of the third occipital nerve (TON) during the occipital migraine surgery does not improve clinical outcomes. When this nerve is encountered during the dissection of the GON, it is sacrificed, but the superficial compression of the TON does not contribute significantly to the onset of occipital migraine headaches. Guyuron et al. described their surgical procedure to treat occipital migraine [6]. With the patient prone, under general anesthesia, a horizontal 5- to 6-cm incision is made approximately 3 cm below the occipital protuberance. After reaching the trapezius muscle in the deep anatomical planes, a vertical incision is made over his fascia, where 1–3 mm of vertically oriented muscle fibers is present. If the avulsion of TON is performed, the third occipital nerve is allowed to retract into the portion of the semispinalis capitis muscle to avoid the scar entrapped it, causing a painful neuroma. If the trapezius muscle extends to the midline raphe, it is divided and retracted laterally, and the semispinalis muscle is then further exposed. The trunk of the GON is located usually approximately 1.5 cm from the midline and 3 cm caudal to the occipital protuberance and is identified when the dissection continues under the trapezius fascia and muscle laterally. The GON is released from surrounding muscle and any fascial bands overlying the nerve until the subcutaneous plane is reached. Furthermore, a 2-cm-long segment of the semispinalis capitis muscle between the nerve and the midline raphe is removed. When the occipital artery is ectasic and entangled with the nerve (**Figures 3**–**4**), the ligation is performed, and the GON is separated from the remaining muscle by placing a laterally elevated subcutaneous flap deeply to the nerve. This procedure is then repeated on the opposite side if indicated. Sometimes the muscle fibers of semispinalis capitis are splitting the nerve within; in this case they are also released. When the nerve is within the trapezial tunnel, the dissection is carried distally releasing the GON. This tunnel is the site where the greater occipital nerve penetrates through the trapezial fascial attachments to the occiput, and it has 1- to 2-cm oblique superolateral direction where it often contains angiolymphatics, another possible compression variable that is removed. Our surgical GON bilaterally decompression technique is performed under local anesthesia with the patient prone. After injecting of diluted 40-cc Carbocaine 1% + 40-cc NaCl 0.9% and 20 cc sodium bicarbonate 8.4%, a horizontal occipital scalp incision 6 cm in length is made along the superior nuchal midline to expose subcutaneous structures. No trichotomy is needed, and the scar from the incision will be hidden in the patient's hair. First of all the dissection of occipital muscle is performed; then a minute separation of the trapezius fibers expose the GON and the semispinalis capitis muscle. Trapezius and semispinalis capitis muscle are carefully undermined following the nerve course as far as possible.

**Figure 3.** The dilated left occipital artery constricting the left great occipital nerve (this picture belongs to Prof. Edoardo Raposio).

the scar entrapped it, causing a painful neuroma. If the trapezius muscle extends to the midline raphe, it is divided and retracted laterally, and the semispinalis muscle is then further exposed. The trunk of the GON is located usually approximately 1.5 cm from the midline and 3 cm caudal to the occipital protuberance and is identified when the dissection continues under the trapezius fascia and muscle laterally. The GON is released from surrounding muscle and any fascial bands overlying the nerve until the subcutaneous plane is reached. Furthermore, a 2-cm-long segment of the semispinalis capitis muscle between the nerve and the midline raphe is removed. When the occipital artery is ectasic and entangled with the nerve (**Figures 3**–**4**), the ligation is performed, and the GON is separated from the remaining muscle by placing a laterally elevated subcutaneous flap deeply to the nerve. This procedure is then repeated on the opposite side if indicated. Sometimes the muscle fibers of semispinalis capitis are splitting the nerve within; in this case they are also released. When the nerve is within the trapezial tunnel, the dissection is carried distally releasing the GON. This tunnel is the site where the greater occipital nerve penetrates through the trapezial fascial attachments to the occiput, and it has 1- to 2-cm oblique superolateral direction where it often contains angiolymphatics, another possible compression variable that is removed. Our surgical GON bilaterally decompression technique is performed under local anesthesia with the patient prone. After injecting of diluted 40-cc Carbocaine 1% + 40-cc NaCl 0.9% and 20 cc sodium bicarbonate 8.4%, a horizontal occipital scalp incision 6 cm in length is made along the superior nuchal midline to expose subcutaneous structures. No trichotomy is needed, and the scar from the incision will be hidden in the patient's hair. First of all the dissection of occipital muscle is performed; then a minute separation of the trapezius fibers expose the GON and the semispinalis capitis muscle. Trapezius and semispinalis capitis muscle are

106 Current Perspectives on Less-known Aspects of Headache

carefully undermined following the nerve course as far as possible.

Raposio).

**Figure 3.** The dilated left occipital artery constricting the left great occipital nerve (this picture belongs to Prof. Edoardo

**Figure 4.** Aberrant left occipital arteries compressing the left occipital nerve (this picture belongs to Prof. Edoardo Raposio).

Subsequently the splenius capitis muscle, which is located laterally behind the GON, and the occipital vascular bundle are isolated from the nerve. The proximity of the occipital artery to the greater occipital nerve often seems to cause nerve compression and paroxysmal, throbbing pain. In fact, sometimes the nerve irritation that might be due to the pulsing activity of the occipital artery may be more distended than expected. In this case, the ligation of the occipital artery is performed. At the end of the procedure, after an accurate hemostasis, the cutaneous access is closed with absorbable suture, without any drainage. Presurgical planning should always include questioning for potential pain at lesser occipital nerve compression points. Furthermore, residual migraine pain after occipital nerve decompression of the greater occipital nerve may be attributable to lesser occipital nerve (LON) entrapment and should be evaluated in no responders and partial responders. The occipital artery and fascial bands along its course could potentially compress the lesser occipital nerve. If patients, in addition to compression of the GON, refer pain and symptoms specific to the lesser occipital nerve, a separate incision is made over this nerve at the posterior border of the sternocleidomastoid muscle, and it was avulsed. When a unilateral lesser occipital nerve compression is present, over the path of the LON localized along the middle third of the posterior margin of the sternocleidomastoid, laterally to the first incision of the GON, a 3-cm excision is performed. The lesser occipital nerve can be decompressed or excised and its proximal stump implanted into the muscle. When both bilateral greater occipital nerve and lesser occipital nerve decompressions are performed, two separate incisions are made, one on each side, each to access the ipsilateral greater occipital nerve and the lesser occipital nerve. As regards our experience, when trigger site is identified in the LON, a 4-cm-long lateral occipital incision is performed, followed by the dissection of occipital, trapezius, and a portion of sternocleidomastoid muscles, thus freeing the nerve. If patients present both trigger points, an 8-cm-long medial incision is made and dissection of all abovementioned muscles and vessels (occipital arteries) and isolation of both nerves are performed [15].

#### **3.4. Auriculotemporal nerve**

Auriculotemporal neuralgia has been described in the neurology literature as a syndrome "characterized by attacks of paroxysmal, moderate to severe pain on the preauricular area, often spreading to the ipsilateral temple." Chim et al. in a study concerning the anatomical variations of compression points of the auriculotemporal nerve have identified three specific points that could be surgically treated [5]. The preauricular fascial band compression points (compression points 1 and 2) in the preauricular course of the auriculotemporal nerve were found centered at 13.1 and 11.9 mm anterior and 5.0 and 17.2 mm superior to the most anterosuperior point of the external auditory meatus. The other compression point (compression point 3) is represented by the crossover in the temporal scalp between the auriculotemporal and the superficial temporal artery. Guyuron et al. developed the technique for endoscopic decompression of the zygomaticotemporal branch of the trigeminal nerve, and recently, it has been recognized that the failure of Site II surgery may be because of the lack of identification and decompression of the auriculotemporal nerve. For this reason commonly the auriculotemporal nerve decompression is performed in conjunction with the zygomaticotemporal decompression [5, 6]. We report the endoscopic surgical techniques to decompression-avulsion of the auriculotemporal nerve [5, 6, 15]. The point of maximal tenderness is marked, and Doppler findings to determinate vessel location may be used to avoid injury to the surrounding nerves or difficulty to place the endoscopic access devices. Both techniques can be combined with decompression of the trigger Site II; in that case auriculotemporal nerve is addressed first. In local anesthesia, five- to seven-port incision is designed for Site II surgery, and the 1.5-cm lateral incision is made and is extended anteriorly if necessary. Dissection to identify the vessel and nerve should be performed with blunt tip scissors along the direction of the vessel. The vessel and nerve are commonly found in the superficial layers and along the superficial temporal fascia. The use of blunt tip bipolar and regular suction is enough to safely ligate the vessel and nerve after identification. Although the area of dissection is far cephalad to the temporal branch of the facial nerve, caution should be exercised. The deep temporal fascia is then identified, and placement of endoscope is performed. If one is concerned about an unusually anterior temporal artery causing compression and pain (scars beyond the hairline or proximity to the temporal branch of the facial nerve), ligation of the main trunk of the auriculotemporal nerve in the preauricular area is chosen. The area of maximal tenderness above the temporomandibular joint, which hosts the main trunk of the auriculotemporal nerve, is accessed, and the vessel and nerve are ligated in this area. A 1.5-cm incision is performed 0.5 cm in front of the tragus and above the temporomandibular joint area with the aid of Doppler. The main trunk of the auriculotemporal nerve is identified first, and the vessel is then located in the deeper plane, commonly associated with another small nerve branch. Caution should be used to avoid injury to the facial nerve, which is deep to the dissection, and to the commonly visualized vein, which is in a more superficial plane. Even with vessel ligation in this area, auriculotemporal nerve decompression and superficial temporal artery ligation in the most lateral port should be done, if possible, because of collateral flow that may still exist. If both areas are to be decompressed, lateral port access and decompression are performed first to ensure better visualization of the artery.
