Subfascial dissection and extended temporal muscle detachment for middle fossa approach.

BACKGROUND: The soft tissue dissection for the middle fossa approach requires adequate management of the neuro, vascular, and muscular structures in order to maximize exposure and diminish morbidities. METHODS: An incision anterior to the tragus is performed, extending from the zygomatic process to the superior temporal line. The superior temporal artery is exposed, followed by a subfascial dissection of the frontalis nerve. The temporal muscle is dissected and released from the zygoma. All cranial landmarks are exposed for the 5 × 5 cm temporal fossa craniotomy. CONCLUSION: This novel approach provides a safe and adequate access to perform an extended middle fossa craniotomy.

New anatomical insights of the superficial branch of the zygomaticotemporal nerve for treating temporal migraines: An anatomical study.

The zygomaticotemporal nerve is known to contribute to temporal migraines; however, its precise anatomy remains unknown. The potential accessory branches of the zygomaticotemporal nerve may be considered a cause of continued temporal migraines after surgical procedures. In this study, we defined the novel superficial branch of the zygomaticotemporal nerve (sZTN) and investigated its anatomical course, distribution, and clinical implications. Twenty-two hemifaces from 11 fixed Korean cadavers (six males, five females; mean age, 78.3 years) were used in this study. The piercing points of the sZTN through the deep and superficial layers of the deep temporal fascia, and the superficial temporal fascia were defined as P1, P2, and P3, respectively. The distance of each point from the zygomatic tubercle was measured using an image analysis software. The sZTN ascended between the bone and the temporalis after emerging from the zygomaticotemporal foramen. It then pierced the deep temporal fascia without penetrating the temporalis. After then, it pierced the superficial layer of the deep temporal fascia and turned superiorly toward the upper posterior temple. When the sZTN passed through the superficial temporal fascia, it intersected with the superficial temporal artery in every case. The novel findings of the sZTN may help in the treatment of intractable temporal migraines refractory to injection or surgical procedure. Based on our findings, targeting the sZTN may be applied as an alternative treatment strategy for patients who do not show significant improvement with treatment targeted to trigger sites.

Interfascial approach for pterional craniotomy: technique and adjustments to prevent cosmetic complications.

BACKGROUND: Interfascial dissection for pterional craniotomy is one of the main techniques to expose the pterional region. METHOD: A step-by-step optimized method of interfascial dissection to avoid three main esthetic complications of the pterional approach-upper facial nerve palsy, temporal muscle atrophy, and retro-orbital depression. A video of the interfascial dissection and three artistic drawings are provided in support of this technique. CONCLUSION: A safe method of interfascial dissection, respecting anatomy, and avoiding cosmetic complications has been proposed.

The Relationship of the Temporal Branch of the Facial Nerve to the Fascial Planes of Temporal Region in Human Fetuses.

The aim of this study was to obtain information by assessing the relationship between temporal region fascial structures, fat pads, and temporal branches of facial nerve in human fetuses to use the knowledge on treatment of early childhood period surgeries. This anatomic dissection study was conducted on 40 hemifaces with no visible external abnormalities on their faces. Fascial layers and related fat pads of temporal region were dissected layer by layer beginning from superficial to deep. The relations of temporal branches of facial nerve and temporoparietal fascia and the structures of these fascial layers were evaluated. Temporoparietal fascia showed continuity below zygomatic arc with superficial musculoaponeurotic system. Temporal branches of facial nerve showed a multiple branching. Parotid-masseteric fascia became very thin on the superficial of zygomatic arch and ran with superficial layer of temporal fascia above without attaching to periosteum. Temporal branches of facial nerve entered between multilayered layers of temporoparietal fascia. Temporoparietal fascia became thicker on anterior and middle parts because of the localization of superficial temporal fat pad. Temporal fascia was a 2-layered thick and fibrous tissue enveloping intermediate fat pad. Deep layer connected to periosteum of zygomatic arch and superficial layer continued passing superficial of zygomatic arch and connected to the parotid-masseteric fascia. Deep temporal fat pad was found on the deep to deep layer of temporal fascia and surface of temporal muscle. The findings of this study may contribute to the knowledge of the topographical localization of temporal branches of facial nerve with temporal region fascial structures and fat pads in fetuses.

Fronto-temporal branch of facial nerve within the interfascial fat pad: is the interfascial dissection really safe?

BACKGROUND: The study was conducted to clarify the presence or absence of fronto-temporal branches (FTB) of the facial nerve within the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad. METHODS: Eight formalin-fixed cadaveric heads (16 sides) were used in the study. The course of the facial nerve and the FTB was dissected in its individual tissue planes and followed from the stylomastoid foramen to the frontal region. RESULTS: In the fronto-temporal region, above the zygomatic arch, FTB gives several small twigs running anteriorly in the fat pad above the superficial temporalis fascia and a branch within the temporo-parietal fascia (TPF) to the muscles of the forehead. There were no twigs of the FTB within the interfascial fat pad. CONCLUSIONS: No branches of the FTB are found in the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad. The interfascial dissection can be safely performed without risk of injury to the FTB and potential subsequent frontalis palsy.

Anatomy of the Anterior Deep Temporal Nerve: Implications for Neurotization in Blinking Restoration in Facial Paralysis.

Facial paralysis can lead to dysfunctions in eyelid closure, which is called lagophthalmos. A number of surgical procedures, both dynamic and static, have been described to restore the innervation of the orbicularis oculi muscle that closes the eyelids. This cadaver-based anatomical study aimed to evaluate the anatomy of the anterior, middle, and posterior deep temporal nerves; nerves to the temporalis muscle; and their availability for direct muscle neurotization of the orbicularis oculi. A total of 10 hemisectioned head specimens from 5 adult cadavers (2 men and 3 women) were used in this study. The adequacy of the length of the anterior deep temporal nerve was assessed for direct neorotization of the orbicularis oculi muscle. The mean distances between the originating point of the deep temporal nerves from the mandibular nerve in the infratemporal fossa and their terminal entry points into the muscle were 46.4 (42-51 mm), 42.2 (38-46 mm), and 33.4 mm (26-40 mm) for the anterior, middle and posterior branches of the nerves, respectively. We conclude that the anterior deep temporal nerve is a versatile nerve that can be used for direct muscle neurotization, nerve transfer, and babysitter procedures in selective blinking restoration. Before proceeding with any further clinical use, an anatomical study should be performed with fresh specimens from cadavers.

Silent squamous cell carcinoma invading the orbit following the course of the zygomaticotemporal nerve.

PURPOSE: To evaluate the clinical and histopathological characteristics of silent skin squamous cell carcinomas (SCC) with invasion routes to the orbit. METHODS: Retrospective case studies. Clinical records and histopathological material, therapy and complications were evaluated, together with MRI imaging analyses and literature review on the anatomy of the lateral orbital wall in relation to the zygomatico-temporal nerve channel. RESULTS: Two recent cases of metastatic SCC from het lateral zygomatic region to het orbit are reported. Originally the skin tumors of the first case was diagnosed as benign, but a review of the pathology of these skin tumors showed an invasive SCC. The second case was diagnosed as an atypical SCC. Analysis of possible invasion routes, using both computer tomography (CT) and magnetic resonance imaging (MRI), indicated neither skin nor bone involvement. However, the lateral temporal fossa near the entrance of the zygomatico-temporal channel showed small tumors and pseudo-cysts. The original skin tumor specimens did not show malignant tissue in the surgical margins nor intra- or perineural invasion. CONCLUSIONS: Because the course of the zygomatico-temporal nerve bundle was exactly in line with the original skin tumor, the channel and the orbital tumors, this route should be considered when malignant orbital tumors have a history of or a relation with a periorbital skin-tumor.

Precision of jaw-closing movements for different jaw gaps.

Jaw-closing movements are basic components of physiological motor actions precisely achieving intercuspation without significant interference. The main purpose of this study was to test the hypothesis that, despite an imperfect intercuspal position, the precision of jaw-closing movements fluctuates within the range of physiological closing movements indispensable for meeting intercuspation without significant interference. For 35 healthy subjects, condylar and incisal point positions for fast and slow jaw-closing, interrupted at different jaw gaps by the use of frontal occlusal plateaus, were compared with uninterrupted physiological jaw closing, with identical jaw gaps, using a telemetric system for measuring jaw position. Examiner-guided centric relation served as a clinically relevant reference position. For jaw gaps ≤4 mm, no significant horizontal or vertical displacement differences were observed for the incisal or condylar points among physiological, fast, and slow jaw-closing. However, the jaw positions under these three closing conditions differed significantly from guided centric relation for nearly all experimental jaw gaps. The findings provide evidence of stringent neuromuscular control of jaw-closing movements in the vicinity of intercuspation. These results might be of clinical relevance to occlusal intervention with different objectives.

Perineural invasion of cutaneous squamous cell carcinoma along the zygomaticotemporal nerve.

The vast majority of periocular squamous cell carcinoma spreads intraorbitally along the supraorbital and infraorbital nerves into the cavernous sinus. A patient presented with a history of resected squamous cell carcinoma and pain in the zygomatic distribution. She was found to have temporalis involvement of the malignancy and invasion of the zygomaticotemporal nerve by histopathology. She underwent aggressive resection and adjuvant treatment with no evidence of recurrence at 8-month follow up. This case illustrates an uncommon route of squamous cell carcinoma spread through the zygomaticotemporal sensory nerve distribution.

Evidence for the functional compartmentalization of the temporalis muscle: a 3-dimensional study of innervation.

PURPOSE: The temporalis muscle is commonly used for functional transfer. It is architecturally complex, but few studies have examined its intramuscular innervation and none has used 3-dimensional modeling techniques. Understanding neuromuscular compartmentalization may allow the design of local muscle transfers to minimize donor-site morbidity. The purpose of the present study was to document the intramuscular innervation patterns throughout the volume of the temporalis muscle and define functional units within the muscle. MATERIALS AND METHODS: In 10 formalin-embalmed cadaveric specimens, the foramen ovale was exposed and the branches of the mandibular nerve were identified. Each branch was digitized in short segments extramuscularly and intramuscularly. Three-dimensional models were reconstructed from the digitized data using Maya software, and the innervation patterns were documented. RESULTS: The temporalis muscle was found to have superior and inferior parts that were further grouped by innervation into regions, with each receiving its innervation from 1 primary nerve. The nerves originated directly from the mandibular nerve, except in 3 specimens, where the posterior deep temporal nerve arose from the masseteric nerve. CONCLUSION: These results provide a detailed mapping of innervation patterns and suggest there are at least 5 functional compartments. Each of these has the capacity for selective activation, 3 of which have clinical value. These findings may allow for decreased donor-site morbidity and more functionally sophisticated designs in clinical practice.

Deep subfascial approach to the temporal area.

PURPOSE: Surgical access to the temporomandibular joint (TMJ) and zygomatic arch is a challenge even to the experienced maxillofacial surgeon. The conventional subfascial approach to these structures carries the potential risk of transient paralysis of the frontalis and orbicularis oculi muscles. This article discusses the use of a deep subfascial approach to access the TMJ and zygomatic arch. This surgical technique provides a safe operating field without jeopardizing the branches of the facial nerve. PATIENTS AND METHODS: A study was carried out on 12 patients, wherein 15 surgical exposures were made, to access the TMJ and zygomatic arch. A deep subfascial approach was used that preserved the structural and functional integrity of the temporal and zygomatic branches. RESULTS: Postoperatively, no functional deficit was noted in either the temporal or zygomatic branches of the facial nerve as ascertained by clinical examination. CONCLUSIONS: The deep subfascial approach preserves and protects the branches of the facial nerve. It relies on distinct anatomic planes that are easily identified during surgery; and hence, the technique becomes relatively simple and easy to use.

Rapid and accurate identification of cut ends of facial nerves using a nerve monitoring system during surgical exploration and anastomosis.

PURPOSE: Surgical exploration and end-to-end neurorrhaphy is the preferred management for traumatic facial nerve injury. Traditionally, finding the cut ends of facial nerves depends mainly on a surgeon's experience. In this study, a nerve monitoring system to help the surgeon quickly and accurately identify, confirm, and locate the cut ends of facial nerve branches was investigated. PATIENTS AND METHODS: Six patients with traumatic facial nerve injury were selected, and the nerve monitoring system was applied during the surgical process of facial nerve exploration and anastomosis. Operation time and surgical outcome were used to evaluate the effect of this method. RESULTS: The surgical procedures required 6 to 15 minutes (mean, 10 minutes) for detecting and dissecting each cut end of a facial nerve branch. All cut ends of injured facial nerve branches were found during surgery in all 6 patients, and no intraoperative complications were encountered. The postoperative function of the facial nerve, evaluated by clinical examination and diagnostic electroneurography, was satisfactory and symmetrical in all 6 patients at 3 months. CONCLUSION: Using a nerve monitoring system could effectively help surgeons achieve rapid and accurate identification of the cut ends of facial nerves during surgical facial nerve exploration for traumatic facial nerve injury.

Clinical anatomy of the periocular region.

The aims of this article are twofold: (1) to provide the facial plastic surgeon with a comprehensive and up-to-date overview of periocular anatomy including the brow, midface, and temporal region and (2) to highlight important anatomical relationships that must be appreciated in order to achieve the best possible functional and aesthetic surgical outcomes.

[Lengthening temporalis myoplasty: A new approach to facial rehabilitation with the "mirror-effect" method]. / Rééducation des paralysies faciales après myoplastie d'allongement du muscle temporal. Intérêt du protocole « effet-miroir ¼

Peripheral facial paralysis often reveals two conditions that are hard to control: labial occlusion and palpebral closure. Today, there are efforts to go beyond the sole use of muscle stimulation techniques, and attention is being given to cerebral plasticity stimulation? This implies using the facial nerves' efferent pathway as the afferent pathway in rehabilitation. This technique could further help limit the two recalcitrant problems, above. We matched two groups of patients who underwent surgery for peripheral facial paralysis by lengthening the temporalis myoplasty (LTM). LTM is one of the best ways to examine cerebral plasticity. The trigeminal nerve is a mixed nerve and is both motor and sensory. After a LTM, patients have to use the trigeminal nerve differently, as it now has a direct role in generating the smile. The LTM approach, using the efferent pathway, therefore, creates a challenge for the brain. The two groups followed separate therapies called "classical" and "mirror-effect". The "mirror-effect" method gave a more precise orientation of the patient's cerebral plasticity than did the classical rehabilitation. The method develops two axes: voluntary movements patients need to control their temporal smile; and spontaneous movements needed for facial expressions. Work on voluntary movements is done before a "digital mirror", using an identical doubled hemiface, providing the patient with a fake copy of his face and, thus, a 7 "mirror-effect". The spontaneous movements work is based on what we call the "Therapy of Motor Emotions". The method presented here is used to treat facial paralysis (Bell's Palsies type), whether requiring surgery or not. Importantly, the facial nerve, like the trigeminal nerve above, is also a mixed nerve and is stimulated through the efferent pathway in the same manner.

Lengthening temporalis myoplasty and brain plasticity: a functional magnetic resonance imaging study.

BACKGROUND: Lengthening temporalis myoplasty (LTM) is a technique developed since ten years for facial paralysis. A spontaneous smile is acquired after this surgery explains by brain plasticity and the aim of the study is to confirm this plasticity by functional magnetic resonance imaging. MATERIALS AND METHODS: A functional magnetic resonance imaging (fMRI) was performed at various time points in ten patients who were operated on LTM during one year. RESULTS: Two different areas were found to be involved in chewing and smiling. We observed changes in the areas involved in smiling and chewing three months after surgery, and these changes persisted for at least one year. CONCLUSIONS: Our findings thus confirm that brain plasticity underlies the clinical observation of acquisition of a spontaneous smile.

Differential activation of proapoptotic molecules between mouse and rat models of distal motor trigeminal denervation.

BACKGROUND: We previously developed a rat trigeminal motor neuron axotomy model involving masseter and temporal muscle resection to study pathological changes of the central nucleus after peripheral nerve injury caused by oral surgery. Because motor neurons are reported to be more vulnerable to axotomy in mice than rats, we compared the degeneration process of the trigeminal motor nucleus in the rat model with a similar mouse model. METHODS: We removed masseter and temporal muscles of adult mice or rats. Animals were sacrificed at 3, 7, 14, 28, 42, and 56 days post-operation, and the trigeminal motor nuclei were histologically analyzed. RESULTS: Size reduction, but no neuronal loss, was seen in the trigeminal motor nuclei in both mice and rats. Time-dependent Noxa expression, starting at 1 week post-operation (wpo), was seen in the mouse model. By 8 wpo, mice expressed a higher level of Noxa than rats. Additionally, we noted persistent expression of cleaved caspase-3 in mice but not in rats. Conversely, apoptosis-inducing factor (AIF), which executes DNA fragmentation in the nucleus, was not translocated to the nucleus in either model. CONCLUSIONS: Our findings indicate differential activation of motor neuron apoptosis pathways after axotomy in mice and rats. Lack of activation of caspase-independent pathways and distal end denervation in our model might be related to the survival of motor neurons after axonal injury. These findings could be relevant to future neuroprotective strategies for peripheral nerve injury caused by oral surgeries.

Hemimasticatory spasm treated with microvascular decompression of the trigeminal nerve.

Hemimasticatory spasm is a very rare disorder of the trigeminal nerve characterized by paroxysmal involuntary contraction of the jaw-closing muscles. The mechanisms leading to hemimasticatory spasm are still unclear. Recently, injection of botulinum toxin has become the treatment of choice due to its excellent results. We report a case of a successful treatment of hemimasticatory spasm via microvascular decompression of the motor branch of the trigeminal nerve.

Contemporary techniques for the correction of temporal hollowing: augmentation temporoplasty with the classic dermal fat graft.

INTRODUCTION: Temporal hollowing is a depression within the soft tissues overlying the temporal fossa, sometimes seen after surgical dissection for access to the facial skeleton. Surgeons have successfully used bone grafts, hydroxyapatite, methyl methacrylate, and autogenous tissue to correct the deformity. A systematic review of the literature demonstrated that the most popular technique for the correction of temporal hollowing seems to be the use of nonbiologic materials. These materials have been used successfully but are associated with some complications. There has been a growing experience with augmentation of the soft tissues of the temporal fossa using dermal fat grafts at our institutions, and this article describes this experience. METHODS: Two senior surgeons' recent experience with the correction of temporal hollowing was reviewed and analyzed. RESULTS: The retrospective review revealed 5 cases of temporal hollowing treated with dermal fat graft placement. Follow-up at 1 year revealed aesthetically pleasing results. CONCLUSIONS: A thorough understanding of temporal anatomy and conscious effort to respect structural integrity during dissection are essential in avoiding temporal hollowing. Sometimes, however, this deformity is impossible to avoid. In these patients, there are a number of options for correction. Open placement of the classic dermal fat graft is a technique that seems to offer good long-term aesthetic results.

Site-to-site variation of muscle activity and sensitivity in the human anterior temporalis muscle: implications for contingent stimulation.

OBJECTIVE: To evaluate variation of electromyographic (EMG) activity and sensitivity between different sites of anterior temporalis (AT) muscle. MATERIALS AND METHODS: Sixteen healthy subjects (eight men: 28.8 ± 5.2 year old and eight women: 29.1 ± 3.9) participated in one experimental session. EMG activity during masticatory muscle contraction was recorded from nine sites at the AT muscle in a 3 × 3 grid with 1 cm between. The subjects maintained steady 30% of maximal voluntary contraction (MVC) using visual feedback. The surface EMG electrode was moved sequentially between these nine test sites and the contractions were repeated. One site was tested four times to assess test-re-test variability. The sensory threshold to electrical stimulation and impedance was also measured at the same sites as the placement of EMG electrodes. RESULTS: The 30% MVC force values did not differ between sites (p = 0.863) or within the same site (p = 0.995) due to the feedback. The EMG activity during 30% MVC was highest at the anterior-superior site (p < 0.05) with a marginal difference within the same site (p = 0.044). Impedance was higher at the posterior-superior, posterior-middle and posterior-inferior sites (p < 0.05). The sensory threshold was highest at the posterior-superior site (p < 0.05). CONCLUSION: These findings showed that electrodes close to the hairline have higher impedance and sensory thresholds and should be avoided. The anterior-superior site produces the highest EMG activity and lower sensory thresholds and can be recommended as the optimal site to place the electrode for contingent stimulation.

Use of temporalis fascia as an interpositional arthroplasty in temporomandibular joint ankylosis: analysis of 8 cases.

PURPOSE: Different interpositional materials have been used to prevent recurrence after gap arthroplasty in temporomandibular joint ankylosis. In this study, the versatility of the temporalis fascia as an interpositional arthroplasty was evaluated. MATERIALS AND METHODS: Eight cases of unilateral temporomandibular joint ankylosis were evaluated, with a follow-up of 11 months to 6 years. RESULTS: Patients had a preoperative maximal interincisal opening of 1 to 9 mm (mean, 2.75 mm). During the last follow-up observation after surgery, patients had a maximum interincisal opening of 32 to 40 mm (mean, 36.5 mm). Deviation to the affected side was observed in all cases. Paresthesia or anesthesia of the temporal branch of facial nerve was absent in all cases. Periodic panoramic radiographs showed that the intra-articular space was well maintained because of interposed tissue, without signs of relapse. There were no signs of reankylosis in any patient. CONCLUSION: The findings of this study show that the temporalis fascia is a good alternative for interpositional arthroplasty.