Nerve to the zygomaticus major muscle: An anatomical study and surgical application to smile reconstruction.

Smile reconstruction using the branches that supply the zygomaticus major muscle as a motor source is an established procedure in facial reanimation surgery for facial paralysis. However, the anatomy of the nerve to the muscle remains unclear. Therefore, we herein examined the topographical anatomy of the nerve to the zygomaticus major muscle to obtain more detailed information on donor nerve anatomy. Preserved cadaver dissection was performed under a microscope on 13 hemifaces of 8 specimens. The branches that innervate the zygomaticus major muscle and their peripheral routes medial to the muscle were traced and examined. A median of four (ranges 2-4) branches innervated the zygomaticus major muscle. The proximal two branches (near the muscle origin) arose from the zygomatic branch, the second of which was the major branch. The distal branches (near the oral commissure) arose from the buccal branch or zygomaticobuccal plexus. The vertical distance from the caudal margin of the zygomatic arch to the major branch intersecting point was 19 ± 4.0 mm, while the horizontal distance parallel to the Frankfort plane was 29 ± 5.2 mm. The proximal two branches innervating the zygomaticus major muscle were detected in the majority of specimens. The anatomical findings obtained herein on the nerve to the zygomaticus major muscle will allow for more reliable donor selection in facial reanimation surgery.

Hypoglossal-Facial Side-to-End Neurorrhaphy With Concomitant Masseteric-Zygomatic Nerve Branch Coaptation and Muscle Transfer for Facial Reanimation: Technique and Case Report.

BACKGROUND: Hypoglossal-facial direct side-to-end neurorrhaphy has become widely used for facial reanimation in patients with irreversible facial nerve damage. Although this procedure achieves good restoration of facial function, it has disadvantages such as mass movement and lack of spontaneity. OBJECTIVE: To present a new facial reanimation technique using hypoglossal-facial direct side-to-end neurorrhaphy with concomitant masseteric-zygomatic nerve branch coaptation and secondary muscle transfer to reduce mass movement and achieve a spontaneous smile in patients with facial paralysis. METHODS: This article describes a novel facial reanimation technique that employs hypoglossal and masseteric nerve transfer combined with secondary vascularized functional gracilis muscle transfer. RESULTS: Details of the technique are reported in a patient with complete facial paralysis after brain surgery. The hypoglossal nerve was partially served and connected to the mastoid segment of the facial nerve by side-to-end anastomosis to restore facial symmetry. A nerve supplying the masseter muscle was coapted with a zygomatic branch by end-to-end anastomosis to restore voluntary movement of the oral commissure, as well as to assist with eye closure. A cross face sural nerve graft was connected to zygomatic branches on the healthy side. In the second stage, a vascularized functional gracilis muscle graft was transplanted using the cross face nerve graft as the donor nerve to restore a natural smile. CONCLUSION: Hypoglossal-facial neurorrhaphy with concomitant masseteric-zygomatic nerve branch coaptation and muscle transfer is an alternative facial reanimation technique that reduces mass movement and achieves a natural smile.

Titanium Mesh Implant Exposure Due To Pressure Gradient Fluctuation.

OBJECTIVE: Titanium mesh implants (TMIs) are used for various purposes in craniotomy. Although delayed implant exposure and thinning of the overlying skin are well-known complications, the mechanism has not yet been elucidated. We reviewed our cases and propose a mechanism for TMI exposure. METHODS: From 2009 to 2018, we treated 14 patients with delayed titanium implant exposure after craniotomy. The exposed titanium implant was a TMI in 4 patients, a titanium mesh plate in 6 patients, and a titanium fixation plate with holes in 4 patients. We reviewed the preoperative computed tomography (CT) scans and operative findings. RESULTS: The interval between craniotomy and implant exposure was 13 years (range, 5-27). Implant exposure occurred at the temporal region in 7 patients, frontal region in 6 patients, and parietal region in 1 patient. The skin ulcer size ranged from 0.25 to 10 cm2 (mean, 1.95). In the patients with TMI exposure, the dura was expanded, and no residual epidural space was identified on the CT scans; however, epidural dead space was revealed on the CT scan in the patients with titanium mesh plate or titanium fixation plate exposure. CONCLUSIONS: We believe that the key factor resulting in delayed titanium mesh exposure is the pressure gradient between the atmosphere and the intracranial space. Fluctuation of this gradient exerts dynamic stress on the tissue in the mesh holes and the adjacent tissue, resulting in tissue damage and implant exposure.

Immediate Cranioplasty for Postcranioplasty Infection in Patients with Ventriculoperitoneal Shunt.

BACKGROUND: Patients with a ventriculoperitoneal (VP) shunt tend to develop epidural fluid accumulation after cranioplasty and also have a higher frequency of syndrome of the trephined after bone flap removal. Thus treatment of patients with postcranioplasty infection and a VP shunt is often challenging. CASE DESCRIPTION: We treated 2 patients with postcranioplasty infection and a VP shunt. One patient had undergone decompressive craniectomy for cerebral hemorrhage, and the other patient had a large frontal dead space following resection of a brain tumor. Both patients were treated by immediate cranioplasty with obliteration of the epidural dead space by using a vascularized free latissimus dorsi muscle flap. In both of them, the postoperative course was uneventful without any complications. CONCLUSIONS: Immediate cranioplasty and obliteration of the epidural dead space with a vascularized free latissimus dorsi muscle flap is an alternative for patients with postcranioplasty infection who are unfavorable candidates for temporary bone flap removal because of the risk of neurologic deterioration.

Differential Reanimation of the Midface and Lower Face Using the Masseteric and Hypoglossal Nerves for Facial Paralysis.

BACKGROUND: Hypoglossal nerve transfer is frequently employed to reanimate the paralyzed facial muscles after irreversible proximal facial nerve injury. However, it can cause significant postoperative synkinesis because it involves the reinnervation of the whole mimetic musculature using a single motor source. OBJECTIVE: To describe our experience with differential reanimation of the midface and lower face using separate motor sources in patients with short-term facial paralysis after brain surgery. METHODS: Seven patients underwent combined nerve transfer (the masseteric nerve to the zygomatic branch and the hypoglossal nerve to the cervicofacial division of the facial nerve) and cross-facial nerve grafting with the aim of achieving a spontaneous smile. The median duration of paralysis before surgery was 7 mo and follow-up ranged from 7 to 31 mo (mean: 18 mo). For evaluation, both physical examination and video analysis were performed. RESULTS: In all patients, reanimation of both the midface and the lower face was successful. A nearly symmetrical resting lip was achieved in all patients, and they were able to voluntarily elevate the corners of their mouths without visible synkinesis and to close their eyes while biting. No patient experienced impairment of masticatory function or tongue atrophy. CONCLUSION: Differential reanimation of the midface and lower face with the masseteric and hypoglossal nerves is an alternative method that helps to minimize synkinetic mass movement and morbidity at the donor site.

Versatility of the Latissimus Dorsi Free Flap during the Treatment of Complex Postcraniotomy Surgical Site Infections.

BACKGROUND: Some intractable cases of postcraniotomy infection, which can involve compromised skin, an open frontal air sinus, and residual epidural dead space, have been reported. In such cases, reconstructing the scalp and skull is challenging. METHODS: Between 2009 and 2016, the author treated 12 patients with recalcitrant postcraniotomy surgical site infections with latissimus dorsi (LD) free flaps. The patients' ages ranged from 37 to 79 years (mean, 63.5 years), and their underlying diseases included subarachnoid hemorrhaging (n = 5), brain tumors (n = 4), and cerebral arteriovenous malformations (n = 3). RESULTS: The LD free flap was used for scalp reconstruction in 3 cases, scalp reconstruction and separation of the intracranial and nasal cavities in 5 cases, and the obliteration of epidural dead space in 4 cases. Debridement followed by staged cranial reconstruction was carried out in 8 cases, and single-stage cranial reconstruction was conducted in 2 cases. The bone defects of the other 2 cases, which were small, were filled with LD musculo-adipose free flaps. The postoperative local appearance of the wounds was acceptable in every case, and no complications occurred. CONCLUSIONS: The LD free flap is a versatile tool for the treatment of complex postcraniotomy surgical site infections. This vascularized muscle flap is useful for controlling local infections because of its abundant vascularity. Moreover, its variety of uses means that it can resolve several problems in cases involving complex cranial wounds.

Masseteric Nerve as "Baby Sitter" Procedure in Incomplete Facial Paralysis.

Supplemental Digital Content is available in the text.

Masseter Atrophication after Masseteric Nerve Transfer. Is It Negligible?

Supplemental Digital Content is available in the text.

Selective orbicularis neuromyectomy for postparetic periocular synkinesis.

BACKGROUND: Facial synkinesis is a distressing consequence of incomplete recovery from facial paralysis. The author presents selective orbicularis neuromyectomy as an alternative surgical treatment for periocular synkinesis. METHODS: Eleven patients (eight women and three men; mean age: 67 years; range: 50-77 years) with postparetic facial synkinesis underwent selective orbicularis neuromyectomy at our hospital between March 2010 and December 2013. All 11 patients exhibited ocular hypertonicity and synkinetic eye closure during voluntary oral movements. The causes of the subjects' facial palsy were as follows: Bell's palsy, seven cases; Hunt's syndrome, two cases; and brain tumor resection, two cases. The patients' preoperative and postoperative facial function levels were evaluated using the Sunnybrook scale. RESULTS: The mean duration of the follow-up period was 37 months (range: 12-57 months). During follow-up, all 11 patients showed decreasing ocular hypertonicity and less marked synkinetic ocular movements. The subjects' mean synkinesis score fell by 4.5 points (48%). One patient demonstrated lower lid ectropion at 1 postoperative month, which was repaired secondarily. No other postoperative complications occurred. CONCLUSIONS: Selective orbicularis neuromyectomy is simple and effective for patients who exhibit periocular synkinesis after facial paralysis, and it should be considered as an alternative treatment for periocular synkinesis.

Masseteric nerve transfer for short-term facial paralysis following skull base surgery.

BACKGROUND: Nerve transfers have been widely used to reanimate paralyzed facial muscles after irreversible proximal injuries to the facial nerve. The author has developed a technique involving masseteric nerve transfer combined with cross-facial nerve grafting for treating skull base surgery-induced facial paralysis. This paper aims to demonstrate that this procedure is effective and causes negligible donor site morbidity. METHODS: Seven patients who developed facial paralysis after the removal of skull base tumors were treated with masseteric nerve transfer combined with cross-facial nerve grafting with the aim of reanimating the midface. The mean period of preoperative paralysis was 6 months. The follow-up period ranged from 22 to 65 months (mean: 46 months). The patients were evaluated with physical examinations and video analysis. RESULTS: Successful reanimation of the midface was achieved in all patients except one, whose muscle tone recovered. On average, facial motion developed 4 months after the nerve transfer. Only minimal coordinated eyelid movement was seen during biting. None of the patients experienced impaired masticatory function or visible wasting of the masseter muscle. All of the patients who recovered the ability to contract their paralyzed muscles were able to close their eyes tightly during biting; however, none of the patients have been able to achieve an effortless spontaneous smile. CONCLUSIONS: Masseteric nerve transfer is an alternative method for selective reanimation of the midface and does not cause donor site morbidity.

Cranial Reconstruction following the Removal of an Infected Synthetic Dura Mater Substitute.

BACKGROUND: The objective of this study was to describe the outcomes of an algorithmic approach to cranial reconstruction following the removal of an infected synthetic dura mater substitute due to postcraniotomy infection. METHODS: A retrospective review was conducted of the cases of 12 patients who underwent cranial reconstruction from 2006 to 2013 after the removal of an infected expanded polytetrafluoroethylene sheet (a synthetic dura mater substitute) due to postcraniotomy infection. RESULTS: Average patient age was 46 years (range, 19-70 years). Follow-up was 4.6 years. The expanded polytetrafluoroethylene sheets were implanted after decompressive craniectomy or after combined resection of the dura mater and a tumor. Epidural, but not subdural, abscesses were found in 6 patients, in whom a sufficient capsule developed underneath the synthetic dura mater. Both epidural and subdural abscesses were found in the remaining 6 patients, and the capsule remained intact after debridement of the subdural abscesses in half of them. Secondary cranial reconstruction was safely performed by leaving the capsule intact in the 9 cases in which no additional dural reconstruction was performed. In the remaining 3 patients, in whom no capsule remained after debridement, secondary cranial reconstruction was carried out by leaving the pericranium over the brain surface. None of the patients developed postoperative complications in follow-up periods. CONCLUSIONS: Staged cranial reconstruction after the removal of an infected synthetic dura mater substitute using an algorithmic approach is feasible and safe, produces satisfactory cosmetic results, and is not associated with any complications.

Modified cranialization and secondary cranioplasty for frontal sinus infection after craniotomy: technical note.

Frontal sinus infection after incorrect treatment of an opened frontal sinus may require extended approaches. This article aims to introduce modified cranialization technique and secondary cranioplasty for frontal sinus infection involving the frontal sinus outflow tract after craniotomy. Eight patients with delayed onset frontal sinus infection involving frontal outflow tract after craniotomy were treated from 2008 to 2012. Debridement and cranialization involving the elimination of the frontal outflow tract was performed. Unilateral sinus cranialization combined with reduction of the non-affected contralateral sinus was carried out for the patients with unilateral sinusitis. A pericranial-frontalis muscle flap was used to separate the intracranial and extracranial spaces. Secondary cranioplasty with hydroxyapatite was performed approximately 3 months after the cranialization. The patients' original conditions included brain tumors (n = 3), frontal sinus fractures (n = 2), and subarachnoid hemorrhage (n = 3). The mean interval between the initial treatment and the onset of sinus infection was 23 years. The frontal sinus infection was bilateral in six cases and unilateral in two cases. Frontal sinus outflow tract was involved in sinus infection in every case. None of the patients suffered recurrent rhinogenic infections within the follow-up period (mean = 35 months) after the secondary cranioplasty. Aesthetic results were satisfactory in every case. Modified cranialization involving elimination of the frontal outflow tract is an alternative method for the patients with pathology in the frontal outflow tract after frontal craniotomy. Secondary cranioplasty provides an esthetically pleasing appearance in such cases.

Medial maxillary fractures revisited.

BACKGROUND: We consider medial maxillary fractures to be a unique type of nasomaxillary buttress fracture involving the lateral margin of the piriform aperture, the maxillary frontal process and the medial aspect of the infraorbital rim. This article aims to define medial maxillary fractures as a unique type of facial bone fracture. METHODS: Eight patients with medial maxillary fractures were treated at our hospital from May 2010 to June 2013. Every patient was preoperatively evaluated using three-dimensional and multidimensional computed tomographic scans and surgically treated. RESULTS: The subjects were seven men and one woman (mean age: 17.5 years). The common mechanism of injury was interpersonal impact followed by small object impact. All of the patients exhibited epistaxis and hypoaesthesia affecting the maxillary nerve and/or its branches, and some patients also displayed nasal deformities and/or diplopia. An oral approach was employed in every case, and it was combined with a subciliary approach in some cases. Medial maxillary fractures involve the maxilla, lacrimal bone, ethmoid bone and/or nasal bone. The main difference between medial maxillary fractures and nasoethmoid orbital fractures is the bones they affect. CONCLUSIONS: Medial maxillary fractures are a unique type of nasomaxillary buttress fracture and should be classified as such because of the bones they affect, their symptoms and the surgical approaches used to treat them.

Orbital fracture deterioration after scuba diving.

Sinus barotrauma is a common disease in divers. However, it is not familiar to maxillofacial surgeon. We presented orbital fracture deterioration by sinus barotrauma in scuba diving and a review of literatures. We also discussed the clinical features, the prevention, and the possible mechanism of orbital fracture deterioration after scuba diving.

One-piece versus two-piece orbitozygomatic craniotomy: quantitative and qualitative considerations.

OBJECTIVE: The orbitozygomatic (OZ) craniotomy minimizes brain retraction and improves cranial base exposure by providing a multidirectional view, increased operative angles and working space. The two main variations of the approach include the one-piece and the two-piece types. The microsurgical anatomy of the one- and two-piece OZ craniotomies are presented with the goal of comparing the extent of orbital roof removal between these two craniotomies and the effect of orbital roof removal on operative exposure. METHODS: Ten two-piece and 11 one-piece OZ craniotomies were performed in a stepwise manner simulating the approaches on formalin fixed specimens. The orbital surface area removed above the frontozygomatic suture extending medially over the orbital roof was measured from each bone flap. The two-sided unpaired t test using STATA 7.0 software was used to compare the amount of orbital roof removed using the two approaches. RESULTS: The two-piece OZ craniotomy allowed for the removal of a larger portion of the roof and lateral wall of the orbit than the one-piece. The total orbitotomy, including the orbital roof plus the part of the lateral wall above the frontozygomatic suture, had an average surface area of 996 +/- 229 mm for the two piece and 372 +/- 103 mm for the one-piece. The orbital roof made up 27 +/- 18% of the orbital osteotomy for the one-piece craniotomies and 67 +/- 10% of the osteotomy for the two-piece craniotomies (P < 0.001). CONCLUSION: The two-piece OZ craniotomy allows for more extensive orbital roof removal and better visualization of the basal frontal lobe. Therefore, the two-piece may result in a lower incidence of enophtalmus and poor cosmetic outcomes, particularly if the remaining orbital roof must be removed piecemeal during the one-piece OZ craniotomy in order to obtain satisfactory exposure.

Scalp to meningeal arterial anastomosis in the parietal foramen.

OBJECTIVE: The purpose of this study was to examine the parietal foramen and to determine whether it is the site of an anastomosis between the meningeal and scalp arteries. METHODS: Forty parietal regions from 20 adult cadavers, in which the arteries were perfused with colored latex, were examined for this study. The scalp was separated from the parietal foramen, and the vasculature in the foramen and adjacent scalp and dura were examined using x3 magnification. The scalp arteries that anastomosed with the meningeal arteries through the parietal foramen were followed into the dura after craniotomy. RESULTS: Parietal foramen was found in 20 of the 40 (50%) parietal regions. They were present bilaterally in eight heads and unilaterally in four. Every parietal foramen transmitted an anastomosis between the middle meningeal and scalp arteries. In 11 (55%) of the 20 foramina found in this study, the superficial temporal and occipital artery formed an anastomosis in the galea and pericranial layer that sent a branch through the parietal foramen to anastomose with parietal branches of the middle meningeal artery. In the remaining nine (45%) sides, the middle meningeal artery had a connection through the foramen with a small pericranial artery. CONCLUSION: Every parietal foramen was the site of a connection between the middle meningeal and scalp arteries. The scalp end of the anastomosis most commonly arose in an anastomosis between the superficial temporal and occipital arteries. This anastomosis may be involved in several pathologies.

Vascular anatomy of the anteriorly based pericranial flap.

OBJECTIVE: The purpose of this study was to examine the vascular supply of the anteriorly based frontal pericranial flap to determine whether separating the pericranium from the galea above the orbital rim would devascularize the pericranial flap. METHODS: The arteries supplying and the veins draining the frontal pericranial flap were examined in 17 adult cadavers using x3 to x30 magnification. The arteries were examined on 25 sides and the veins on 16 sides. RESULTS: The main trunk and superficial branches of the supraorbital and supratrochlear arteries, which course in the galea-frontalis muscle layer, give rise to the deep branches that supply the pericranium. These pericranial branches may arise in the orbit or at the level of or above the orbital rim. Pericranial arteries that arose above the level of the orbital rim and would be divided in separating the galea and pericranium were found in 28% of the sides examined. Pericranial veins that coursed above the orbital rim and would be divided in separating the galea-frontalis muscle layer from the pericranial layer were found in 43.8% of the sides examined. CONCLUSION: In preparing a pericranial flap based anteriorly on the supraorbital rim, the separation of the galea-frontalis muscle layer from the pericranium layer should not extend into the 10 mm above the supraorbital rim if the arterial and venous pedicle of the pericranial flap is to be preserved.

MacCarty keyhole and inferior orbital fissure in orbitozygomatic craniotomy.

OBJECTIVE: This study had two objectives. The first was to define the ideal position of the MacCarty keyhole, a commonly used craniotomy entry site into which three of the bone cuts in orbitozygomatic craniotomy extend. The second objective was to examine the relationships in the inferior orbital fissure, a site into which two of the bone cuts in orbitozygomatic craniotomy extend. METHODS: Twenty frontotemporal regions from adult skulls were examined to delineate the relationships between the surface anatomy of the fronto-orbitozygomatic region and the underlying frontal fossa and orbit. Drill holes placed along, above, and below the frontosphenoid suture were made beginning anteriorly at an area referred to as the three-suture junction, located at the junction of the frontozygomatic, sphenozygomatic, and frontosphenoid sutures. The site of the deep end of each hole was recorded to clarify the ideal position of the keyhole. The relationships in the inferior orbital fissure, the site of the lower end of the bone cut that begins in the orbital portion of the keyhole and extends along the lateral orbital wall, were also examined. CONCLUSION: Placing the MacCarty keyhole on the frontosphenoid suture 5 to 6 mm behind the three-suture junction results in greater preservation of the lateral wall and roof of the orbit than when the hole is placed at a more anterior site, as previously recommended. The anterolateral part of the inferior orbital fissure, which faces the temporal fossa and into which the bone cuts in the orbitozygomatic craniotomy extend, has a lower density of vascular and neural structures than the middle and posteromedial parts, which are related to the infratemporal and pterygopalatine fossa.