The temporal branch of the facial nerve: how reliably can we predict its path?

Temporal Hollowing Causes, Classifications, and Treatment Options: A Systematic Review

BACKGROUND

Recent developments in surgical techniques and grading schemas to treat temporal hollowing necessitate critically assessing their efficacy. This systematic review presents the currently available protocols for temporal hollowing, aimed toward improving the clinical approach, for the benefit of the surgeon and patient.

METHODS

A search was conducted in Pubmed, Embase, and Google Scholar in September 2021 using the key words "temporal hollowing" and "temporal augmentation." Inclusion criteria were English written articles published in peer-reviewed journals that reported an outcome relating to the cause, classification, or procedure used to prevent or correct hollowing in humans.

RESULTS

Of the 413, 966 publications retrieved, 24 met the study inclusion criteria. Twenty-one publications discussed the etiology of temporal hollowing, 12 discussed a classification or grading system for temporal hollowing, and 19 discussed a procedure to prevent or correct temporal hollowing. The most commonly reported etiology for temporal hollowing was iatrogenic (63%). For classifying temporal hollowing severity, visual analogue scales (25%) were most commonly used. Mesh (26%) and autologous fat grafts (26%) were the most popular procedures used to prevent or correct temporal hollowing.

DISCUSSION

We presented the spectrum of temporal hollowing grading schemas and treatment modalities currently published in the field. The use, by a majority of publications, of a grading system based on the subjective judgement of the examiner (either alone or adjunct to imaging results) suggests the need for a more standardized measurement tool. Future studies should investigate a universally-applicable temporal hollowing classification system and its impact on treatment outcomes.

Depth Transitions of the Frontal Branch of the Facial Nerve: Implications in SMAS rhytidectomy

Background

Anatomy of the frontal branch of the facial nerve relative to the zygomatic arch and the superficial musculoaponeurotic system (SMAS) has been well described. The variability centers on the location where the frontal branch traverses from a deeper to more superficial plane in the SMAS. The goal of this study is to examine the depth transition of the frontal branch of the facial nerve relative to the zygomatic arch with hopes of pinpointing a caution zone for dissection to avoid nerve injury.

Methods

The frontal branch of the facial nerve was dissected in 36 hemifacial fresh cadaver specimens. Pitanguy's line, the zygomatic arch, and temporal crest were marked. Measurements were taken from the zygomatic arch to the location where the frontal branch pierced the temporoparietal fascia. Locations of the superficial temporal artery (STA), the frontal branch cross relative to the lateral orbital rim and frontalis muscle were also measured.

Results

In 94.4% (n = 36) of the specimens, the frontal branch was found to transition to an intra-SMAS plane approximately 9.6 mm above the zygomatic arch. In all specimens, the frontal branch transitioned to an intra-SMAS plane approximately 12.2 mm posterior to Pitanguy's line.

Conclusions

This study describes a surgical "caution zone" centered on a point 9.6 mm above the arch and 12.2 mm posterior to Pitanguy's line, and related to the anterior branch of the STA. We hope this anatomical detail will help to decrease the likelihood of intraoperative injury to the frontal branch of the facial nerve.

Cadaveric Study of Topographic Anatomy of Temporal and Marginal Mandibular Branches of the Facial Nerve in Relation to Temporomandibular Joint Surgery

PURPOSE

Detailed anatomy of the facial nerve, including the variations among different ethnic groups, is essential to prevent an iatrogenic injury. The purpose of the study was to document topographic anatomy of temporal and marginal mandibular (MM) branches of the facial nerve in relation to temporomandibular joint (TMJ) surgery. The specific aim was to demonstrate detailed course of temporal and MM nerves, their surgical implications, and to compare the results obtained with the previous studies.

METHODS

The investigators implemented a prospective cadaveric study. A dissection was carried out on 52 facial halves. The facial nerve was dissected according to the instructions described in the Cunningham^'s dissection manual. Anatomic landmarks were selected as determined by Al-Kayat and Bramley, and results obtained were compared with previous published articles.

RESULTS

The study sample was composed of 52 facial halves (males, n = 35; females, n = 17). The number of branches of temporal nerve varied in dissected facial halves from 3 (n = 37 [70%]), 2 (n = 14 [26%]), to 1 (n = 1 [2%]). The distance between the lowest concavity of the bony external auditory meatus to the point at which the facial nerve bifurcates (distance B) was considerably less in the study population (1.79 cm) when compared with the reported literature (2.3 cm). There was no significant influence of gender and cephalic index on distances measured. There was 1 branch in 15% of the dissected facial halves (1 in 52) and 2 branches in 85% (44 of 52). The MM nerve was seen coursing below the inferior border of the mandible, and in 44 (85%), the nerve was present above the inferior border of mandible all along the course.

CONCLUSIONS

The topographic anatomy of the temporal and MM nerves is the same as reported in the literature. The only considerable difference was found in distance B; hence, surgical procedures involving the distance B require special consideration.

Postoperative temporal hollowing: Is there a surgical approach that prevents this complication? A systematic review and anatomic illustration

BACKGROUND

Temporal hollowing is a common complication following surgical dissection in the temporal region. Our objectives were to: (1) review and clarify the temporal soft tissue relationships - supplemented by cadaveric dissection - to better understand surgical approach variations and elucidate potential etiologies of postoperative hollowing; (2) identify if there is any evidence to support a surgical approach that prevents hollowing through a systematic review.

METHODS

Cadaveric dissection was performed on six hemi-heads. A systematic review of the literature was undertaken to identify surgical approaches with a decreased risk of postoperative hollowing.

RESULTS

A total of 1212 articles were reviewed; 19 of these met final inclusion criteria. Level I and II evidence supports against the use of a dissection plane beneath the superficial layer of the deep temporal fascia or through the intermediate temporal fat pad. Level II evidence supports preservation of the temporalis muscle origin - no evidence is available to support other temporalis resuspension techniques. For intracranial exposure, refraining from temporal fat pad dissection (Level I Evidence) and use of decreased access approaches such as the minipterional craniotomy (Level I Evidence) appear to minimize temporal soft tissue atrophy.

CONCLUSIONS

This study highlights the significance of preservation of the temporal soft tissue components to prevent hollowing. Preserving the temporalis origin and avoiding dissection between the leaflets of the deep temporal fascia or through the intermediate temporal fat pad appear to minimize this complication.

Assessment of facial nerve injury with "House and Brackmann facial nerve grading system" in patients of temporomandibular joint ankylosis operated using deep subfascial approach

Background:

Preservation of the functional integrity of the facial nerve (FN) is a critical measure of success in temporomandibular joint (TMJ) surgery. In spite of the development of a myriad of surgical approaches to the TMJ, FN remains at risk. The deep subfascial approach provides an additional layer of protection (the deep layer of the temporalis fascia and the superficial temporal fat pad) to the temporal and zygomatic branches of the FN and thus, is the safest method to avoid FN injury.

Objectives:

To assess FN injury following TMJ surgery using deep subfascial approach and measuring it on House and Brackman facial nerve grading system (HBFNGS).

Materials and Methods:

Twenty TMJs in 18 patients were operated for TMJ ankylosis, using “the deep subfascial approach.” FN function was assessed postoperatively at 24 h, 1 week, 1 month, 3 months, 6 months using HBFNGS. Statistical analysis was done using SPSS 16.0.

Results:

Of 20 surgical sites 3 sites showed Grade III (moderate) FN injury and 17 sites showed Grade II (mild) FN injury at 24 h. The condition improved with time with full recovery of FN at all surgical sites at 6 months.

Conclusion:

The deep subfascial approach has a distinct advantage over the conventional approaches when dissecting the temporal region and is the safest method to avoid injury to FN.

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.

Interfascial Dissection for Protection of the Nerve Branches to the Frontalis Muscles during Supraorbital Trans-Eyebrow Approach: An Anatomical Study and Technical Note

Introduction Preservation of the temporal branches of the facial nerve during anterolateral craniotomies is important. Damaging it can inflict undesirable cosmetic defects to the patient. The supraorbital trans-eyebrow approach (SOTE) is a versatile keyhole craniotomy but still has a high rate of frontalis muscle (FM) palsy. Objective Anatomical study to implement the interfascial dissection during the SOTE to preserve the nerves to the FM. Methods Slight modification of the standard technique of the SOTE was performed in 6 cadaveric specimens (12 sides). Results Distal rami to the FM were exposed. The standard "u-shape" incision of the FM can cross over the nerves. Alternatively, an "l-shape" incision was performed until the superior temporal line (STL). An interfascial dissection was performed near to the STL and the interfascial fat pad was used as a protective layer for the nerves. Conclusion Various pathologies can be addressed with the SOTE. In the majority of the cases the cosmetic results are good, but FM palsy remains a drawback of this approach. The interfascial dissection may be used in an attempt to prevent frontalis rami palsy.

Techniques for Preservation of the Frontotemporal Branch of Facial Nerve during Orbitozygomatic Approaches

Background During orbitozygomatic (OZ) approaches, the frontotemporal branch (FTB) of the facial nerve is exposed to injury if proper measures are not taken. This article describes in detail the nuances of the two most common techniques (interfascial and subfascial dissection). Design The FTB of the facial nerve was dissected and followed in its tissue planes on fresh-frozen cadaver heads. The interfascial and subfascial dissections were performed, and every step was photographed and examined. Results The interfascial dissection is safe to be started from the most anterior part of the superior temporal line and followed to the root of the zygoma. The dissection is continued on the deep temporalis fascia (DTF), and the interfascial fat pad is elevated. With the subfascial dissection, both the superficial temporalis fascia and the DTF are elevated. The interfascial dissection exposes the zygomatic arch directly, whereas the subfascial dissection requires an additional cut on the DTF to expose the zygomatic arch. Proper subperiosteal dissection on the zygomatic arch is another important step in FTB preservation. Conclusion Detailed understanding of the complex relationship of the tissue planes in the frontotemporal region is needed to perform OZ exposures safely.

The transeyelid midface lift

The transeyelid approach to midface lift is an elegant approach for mild descent of malar soft tissue. The subciliary approach is the most commonly used and technically less challenging for surgeons experienced in facelift techniques. This technique in midface rejuvenation also has the advantage of ease of combining with other periocular and mid and upper face rejuvenation, such as blepharoplasty and forehead lift. Complication is rare with lid malposition, scaring, and temporary nerve function impairment being the most common.

Endoscopic lateral orbitotomy

Background

Lateral orbitotomy can be minimalized using contemporary endoscopy.

Methods

Anatomy of the temporal fossa/orbital wall junction is described. The attachment of the temporal fascia is cut off from the orbital rim through a 1.5 cm skin incision in the lateral orbital wrinkle. The temporal muscle is detached from the bone to create a space for the telescope. An appropriate bone opening in the lateral orbital wall is created with the aid of neuronavigation to handle intraorbital pathology.

Conclusion

Endoscopic lateral orbitotomy is an original alternative to the microsurgical Krönlein approach and yields good functional and cosmetic results.

Electronic supplementary material

The online version of this article (doi:10.1007/s00701-014-2205-7) contains supplementary material, which is available to authorized users.

Traditional and contemporary surgical approaches to the orbit

Traditional orbital approaches are nearly a century old and still comprise the foundation of techniques used today. Computer-assisted planning and intraoperative navigation have recently been reported with more prevalence in the literature. The purpose of this article was to review commonly used approaches to the orbit: old and new.

Preoperative percutaneous mapping of the frontal branch of the facial nerve to assess the risk of frontalis muscle palsy after a supraorbital keyhole approach

OBJECT

Although a supraorbital keyhole approach utilizing an eyebrow incision and supraorbital minicraniotomy is one of the most commonly used keyhole approaches for treating cerebral aneurysms, the risk of frontalis muscle palsy due to an injury of the frontal branch of the facial nerve remains a serious drawback to a supraorbital keyhole approach as a minimally invasive surgical technique. Therefore, the authors attempted to evaluate the risk of frontalis muscle palsy by mapping the frontal nerve branch in the lower forehead using a nerve conduction study in individual patients.

METHODS

Percutaneous mapping of the frontal nerve branch was performed preoperatively on 52 patients who underwent supraorbital keyhole approaches for aneurysmal clipping. The maximal compound muscle action potentials (CMAPs) in the lower forehead were observed at 5 points along a laterally inclined line angled 30° from the midpupillary line, in which the points were 1.0, 1.5, 2.0, 2.5, and 3.0 cm as measured from the supraorbital margin. ResULTS Severe frontalis muscle palsy was observed in 11 patients (21.2%), yet recovery occurred 2-5 months after surgery. No patients experienced permanent palsy. The incidence of severe palsy was 7.4% in those patients showing clear CMAPs with a high location (exclusively at 2.0, 2.5, or 3.0 cm), 14.3% in those with a bimodal distribution, 40.0% in those with a low location (exclusively at 1.5 cm), and 83.3% in those with an extremely low location (exclusively at 1.0 cm).

CONCLUSIONS

Percutaneous mapping of the frontal branch of the facial nerve using a nerve conduction study can be used to assess the risk of postoperative frontalis muscle palsy following a supraorbital keyhole approach. The patients with the highest risk of postoperative palsy showed a clear CMAP exclusively at 1.0 cm along the inclined line measured from the supraorbital margin.

Combined subgaleal/myocutaneous technique for temporalis muscle dissection

Background The frontal branch of the facial nerve (FBFN) is the most susceptible neural structure to injury during frontotemporal craniotomies. The balance between adequate temporalis muscle mobilization and frontal branch protection with minimal anatomical alteration is the philosophy behind our approach to temporalis muscle dissection. Objective To describe a combined subgaleal/myocutaneous technique for dissection and mobilization of the temporalis muscle in anterolateral cranial approaches. Methods Interdisciplinary literature review of the anatomical course of the FBFN was performed. Retrospective analysis of anterolateral craniotomies performed at our institution in which the combined subgaleal/myocutaneous (CSGMC) technique was performed. Results A total of 71 cases of anterolateral craniotomies (excluding full variant orbitozygomatic) were performed with the successful application of a CSGMC technique (36 pterional, 31 orbitopterional, and 4 fronto-orbital). Partial frontalis weakness was transient in one case. Conclusion The CSGMC technique provides sufficient protection for the FBFN and allows for adequate mobilization for a variety of skull base exposures while minimally violating myofascial anatomy. This is the first reported technique that allows both adequate temporalis muscle mobilization with performance of the one-piece orbitofrontal and orbitopterional approaches, without disruption of the superficial/deep temporalis fascia and fat-pad complex.

The versatility of the temporoparietal fascia flap in head and neck reconstruction

OBJECTIVES

The temporoparietal fascia flap (TPFF) is a versatile tool in head and neck reconstruction. This article aims to describe the spectrum of TPFF applications through a series of case studies and related review of the literature.

METHODS

Medical records were reviewed to identify cases that represent major TPFF application categories. A literature review was performed to support the presentation and discussion of each case category.

RESULTS

Seven cases were identified each representing a distinct application category. These included auricular reconstruction, hair-bearing tissue transfer, facial soft tissue augmentation, cutaneous and mucosal oncologic defect repair, reconstruction after salvage laryngectomy, skull base reconstruction, and orbital reconstruction.

CONCLUSION

The TPFF is a uniquely versatile tool in head and neck reconstructive surgery. Outstanding in its pliable, ultra-thin yet hardy and highly vascular form, the temporoparietal fascia flap is a workhorse for the creative head and neck reconstructive surgeon.

Facial-zygomatic triangle: a relationship between the extracranial portion of facial nerve and the zygomatic arch

BACKGROUND

This study was conducted to clarify the relationships between the extracranial portion of the facial nerve (EFN) and the zygomatic arch (ZA).

METHOD

Four cadaveric heads (8 parotid regions), examined under 3-40x magnification, were dissected from lateral to medial to expose the EFN.

FINDINGS

In a vertical plane just anterior to the tragus, the distance from the superior edge of the ZA to the facial nerve (FN) is, on average, 26.88 mm. The FN then courses superiorly and anteriorly, crossing the ZA 18.65 mm anterior to the tragus on average. Thus, three points can be used to depict a triangle: A, at the level of the anterior border of the tragus, just above the superior edge of the ZA; B, 26 mm below A; and C, 18 mm anterior to A. This so called facial-zygomatic triangle represents the area where surgical dissection can be performed with no risk of damaging the FN. Thus, the closer one stays to the tragus, the lesser the risk of damaging the FN below the ZA. If the incision is carried out on a vertical plane closer to the tragus, the skin can be safely cut up to 2 cm below the ZA.

CONCLUSION

The facial-zygomatic triangle is a very useful superficial landmark to avoid FN damage when working below the ZA.

Reverse-flow retroauricular island flap in facial reconstruction

BACKGROUND

Reconstruction of facial skin defects requires good-quality skin cover to satisfy aesthetic expectations of patient, especially when the skin defect is on the uncovered area of the face. Limitations in the available local tissue and donor-site morbidity restrict the options.

OBJECTIVE

In an effort to solve these problems, we have begun to use a subcutaneous pedicled retroauricular reverse-flow flap.

METHODS

Between January 1997 and December 2005, reverse-flow subcutaneous pedicled retroauricular island flap was used to cover facial defects in 12 patients who underwent surgical excision of skin tumor. The patients ranged in age from 44 to 81 years with a mean age of 58 years.

RESULTS

Only one case experienced a superficial necrosis in the distal one-quarter part of the flap. The functional and aesthetic results were satisfactory for both patients and surgeons, and no tumor recurrence was observed during the 12 to 28 months (mean, 18.8 months) follow-up period.

CONCLUSIONS

This flap can be used reliably for the reconstruction of facial skin defects of small and medium size. The preference of frontal branch pedicled flap enables more distal facial area defects to be covered, such as dorsal nasal, nasolabial, and upper lip, than flaps based on parietal branch.

The relationship of the fronto-temporal branches of the facial nerve to the fascias of the temporal region: a literature review applied to practical anatomical dissection

The understanding of the course of the facial nerve and its relationship to the different connective tissue layers in the temporal area is paramount to preserving this nerve during surgery. But the use of different nomenclatures for anatomical structures such as for the different fascial layers or fat pads in the temporal region as well as the difference in description of the course of the fronto-temporal branches of the facial nerve in relationship to the fascial layers can lead to confusion. Therefore we have reviewed the literature about this topic and tried to apply the information to practical anatomical dissection.

Surgical exposure of lateral orbital lesions using a coronal scalp flap and lateral orbitozygomatic approach: clinical experience

BACKGROUND

The lateral extraconal compartment is a typical localization of intra-orbital tumours. With the exception of anterior lesions, which can be reached by a transconjuntival route, most of these tumours are currently approached through the classic lateral orbitotomy originally described by Kronlein. We present here our experience in the management of lateral orbital lesions, using a coronal skin flap, followed by subfascial dissection of the temporalis muscle. The procedure was intended to overcome the potential drawbacks associated with the classic transtemporal approach.

METHODS

The approach was used in eleven patients harbouring bone lesions of the lateral orbital wall or intra-orbital lesion of the lateral extra-ocular compartment. The postoperative results were assessed using a simple cosmetic outcome scale, which evalutated the temporalis muscle trophism and the function of the frontotemporal branch of the facial nerve.

RESULTS

All lesions were satisfactorily exposed. The subfascial dissection of the temporalis muscle is a key manoeuvre which, at the same time, abolishes the risk of injury to the frontotemporal branch of the facial nerve and provides a wide exposure of the lateral orbital wall. The cosmetic outcome was excellent in 9 patients and good in 2 patients.

CONCLUSIONS

The reported technique is a convenient surgical option to approach lateral intra-orbital lesions, with a minimal cosmetic impact.

Coronal incision for treating zygomatic complex fractures

OBJECTIVES

To study the value of coronal incisions for treating zygomatic complex fractures.

PATIENTS AND METHODS

A retrospective study was conducted on 69 out of 83 patients regarding the indications and complications of scalp incisions for treating zygomatic complex fractures (the other 14 patients were treated by local incisions and approaches).

RESULTS

In the early postoperative period, 5 patients suffered from haemorrhage, 2 had infections, 24 patients reported immediate postoperative anaesthesia and paraesthesia affecting the supraorbital region. Six had symptoms and signs of facial nerve injury: difficulty with wrinkling the forehead or to closing the eyes. After a follow-up of 3-5 years, 6 cases suffered from a scar wider than 0.5 cm, paraesthesia in 2 cases (parietal region and temporal region), depression of the temporal fossa in 2 and 1 patient had (persistent) palsy of the temporal branch of the facial nerve.

CONCLUSION

On one hand, coronal incisions offer advantages such as: extensive exposure to ensure exact anatomical reduction. On the other hand, this incision has disadvantages such as obvious scars, long operating time, infections, haemorrhage, paraesthesia in the operative region, palsy of the facial nerve and depression of the temporal fossa. Therefore, the indications for coronal incisions should be strictly applied, and this incision should not be overused.

Temporoparietal fascia plication in rhytidectomy

BACKGROUND

The temporal region has a complex subcutaneous fascial structure known as the temporoparietal fascia, which is part of the subcutaneous musculoaponeurotic system. The temporoparietal fascia is continuous with the superficial musculoaponeurotic system (SMAS) of the face in the inferior border, the frontalis muscle, and the orbicularis oculi muscle in the anterior border. Therefore, a properly planned temporoparietal fascia plication can increase the tightness of the SMAS. In addition, plication of the temporoparietal fascia can provide lifting to decrease lateral canthal wrinkles with elevation of the lateral brows in rhytidectomy. Furthermore, plication of the temporoparietal fascia can yield deep tissue support, which prevents alopecia and visible scar formation in the temporal region by decreasing the tension along the skin incision.

METHODS

Plication of the temporoparietal fascia was performed for 16 patients who had undergone face-lifts over the previous 10 years. Careful subcutaneous dissection, performed immediately under the hair follicles to avoid frontal nerve injury, provides excellent exposure of the temporoparietal fascia for plication in rhytidectomy and protects the auriculotemporal nerve and the superficial temporal vessels.

RESULTS

There were no complications such as hematoma, facial nerve injury, alopecia, or visible scar formation attributable to the temporoparietal fascia plication.

CONCLUSION

Temporoparietal fascia plication can be performed simply during rhytidectomy as an additional procedure. It not only augments the effects of the rhytidectomy, especially in the lateral brows, the lateral canthal, and the temporal regions, but also decreases the risk of possible complications.

The Frontal-Temporal Nerve Triangle: A New Concept of Locating the Motor and Sensory Nerves in Upper Third of the Face Rhytidectomy

BACKGROUND

How to avoid damage to the temporal branch of the facial nerve has long been a central topic of discussion. Recently, damage to the supraorbital nerve, the auriculotemporal nerve, and other branches of the trigeminal nerve divisions has attracted much attention. Focusing on frontal and temporal rhytidectomy, the authors have investigated the course and distribution of the facial nerve branches, the supraorbital nerve, the auriculotemporal nerve, and other branches of trigeminal division. In this article, they present the concept of the frontal-temporal nerve triangle; its contents, vicinity, and clinical significances are discussed.

METHODS

An anatomical study was performed using 30 temporal-parietal regions of 10 fixed adult cadavers and five fresh cadavers. A step-by-step dissection from the superficial layer to the deep layer was involved; all the measurement data were analyzed, and the mean and standard deviation were calculated and expressed in centimeters.

RESULTS

The frontal-temporal nerve triangle is an approximately triangular area formed by the temporal branch of the facial nerve, the supraorbital nerve, and the auriculotemporal nerve. Together with its contents and vicinal structures, it forms a complicated three-dimensional rather than two-dimensional structure. Anatomical structures closely associated with rhytidectomy are located in or near this area.

CONCLUSIONS

Acting as the anatomical body surface landmark for preoperatively locating the temporal branch, the supraorbital nerve, the auriculotemporal nerve, and its related structures, the concept of the frontal-temporal nerve triangle has practical significance in designing incisions and selecting planes of dissection in upper third of the face rhytidectomy.

Using the Frontal Branch of the Superficial Temporal Artery as a Landmark for Locating the Course of the Temporal Branch of the Facial Nerve during Rhytidectomy: An Anatomical Study

BACKGROUND

Previous studies have proposed that the frontal branch of the superficial temporal artery could be used to determine the course of the temporal branch of the facial nerve; however, these studies have not documented this relationship. The objective of this study was to thoroughly examine the courses of the frontal branch and temporal branch in the temporal region and to describe their relationship in detail. The operating technique used to avoid damaging the temporal branch in the rhytidectomy also is discussed.

METHODS

An anatomical study was performed on 30 temporoparietal regions from 10 fixed adult cadavers and five fresh cadavers. Twenty halves of head-vascular-cast specimens also were observed.

RESULTS

Depending on whether the bifurcation point of the superficial temporal artery is superior or inferior to the horizontal line of the superior orbital rim, the frontal branch can be classified as having a high-location or low-location type. The temporal branch and its terminal twigs run deeper into the superficial temporal fascia and are inferior to the frontal branch in the high-location type. In the low-location type, one or more terminal twigs of the temporal branch interweave with the frontal branch above the horizontal plane of the upper orbital rim and terminate below the frontal eminence. The temporal branch locates within a triangular area formed by the lower aspect of the zygomatic arch, the frontal branch, and the vertical line where it crosses the highest point of the frontal eminence

CONCLUSION

The frontal branch can be the anatomical landmark used to locate and protect the temporal branch during rhytidectomy.

The deep subfascial approach to the temporomandibular joint

PURPOSE

The aim of the present study was to improve safety and visibility in the surgical approach to the temporomandibular joint (TMJ). In spite of the development of a myriad of surgical approaches to the TMJ, the facial nerve remains at risk for damage. For this reason the authors present an additional, safe, surgical approach to avoid injuries of the facial nerve during TMJ surgery, termed "the deep subfascial approach."

PATIENTS AND METHODS

Two resident surgeons, under supervision of the Department Chief, made 29 surgical exposures of the condyle, safely using the deep subfascial approach. This surgical approach is carried out by means of a modified preauricular incision followed by the subfascial dissection. Dissection passes under both layers of the deep temporalis fascia.

RESULTS

Neither permanent nor temporary motor loss of the frontal branch of the facial nerve was observed after surgery. It has not been necessary to ligate the superficial temporal vessels except the posterior branch of the superficial temporal artery. Aesthetic results were excellent in all cases.

CONCLUSION

The operation is technically facile, surgically uncomplicated, and clinically effective. It is our opinion that the deep subfascial approach to the TMJ represents a safe method to avoid injury of the facial nerve. We suggest this surgical procedure as a routine and safe approach to the TMJ and to the zygomatic arch, especially in second procedures or in delayed treatments.

Innervation of the Corrugator Supercilii Muscle

The frowning forehead is unwanted, generally because it gives an impression of anger and displeasure. The frown is formed mainly by the repeated contraction of the corrugator supercilii muscle. We studied the relevant nerve supply to the muscle in detail to enhance selective neurotomy. A bicoronal incision extending downward to the preauricle was made and the subgaleal dissection proceeded in 19 hemifaces of cadavers. The temporal branch of the facial nerve was divided into 2 to 4 smaller branches at the zygomatic arch. There were commonly 3 branches. The temporal branch is located 10 mm lateral to the supraorbital notch or foramen 2.8 to 25 mm above the supraorbital rim. It contains 4 to 7 thin rami (5 on average). A plexus mainly from the inferior ramus partly from the middle ramus of the temporal branch of the facial nerve enters the corrugator supercilii muscle in the supraorbital area. Because the temporal branch had multiple interconnection among its own rami, selective blocking of the middle ramus cannot promise the elimination of the frown line.

The fascial planes of the temple and face: an en-bloc anatomical study and a plea for consistency

Many investigators have detailed the soft tissue anatomy of the face. Despite the broad reference base, confusion remains about the consistent nature of the fascial anatomy of the craniofacial soft tissue envelope in relation to the muscular, neurovascular and specialised structures. This confusion is compounded by the lack of consistent terminology. This study presents a coherent account of the fascial planes of the temple and midface. Ten fresh cadaveric facial halves were dissected, in a level-by-level approach, to display the fascial anatomy of the midface and temporal region. The contralateral 10 facial halves were coronally sectioned through the zygomatic arch at a consistent point anterior to the tragus. These sections were histologically prepared to demonstrate the fascial anatomy en-bloc with the skeletal and specialised soft tissues. Three generic subcutaneous fascial layers consistently characterise the face and temporal regions, and remain in continuity across the zygomatic arch. These three layers are the superficial musculo-aponeurotic system (SMAS), the innominate fascia, and the muscular fasciae. The many inconsistent names previously given to these layers reflect their regional specialisation in the temple, zygomatic area, and midface. Appreciation of the consistency of these layers, which are in continuity with the layers of the scalp, greatly facilitates an understanding of applied craniofacial soft tissue anatomy.

The safe face lift with bony anatomic landmarks to elevate the SMAS

The risk for facial nerve injury has been reported to be increased with the inclusion of superficial musculoaponeurotic system (SMAS) elevation as compared with a skin-only face lift. The facial nerve courses through the parotid gland. The SMAS is elevated superficial to the parotid gland. However, in elevating the SMAS anterior to the parotid gland, the facial nerve is at risk of injury where its branches emerge from the anterior edge of the parotid gland. The purpose of this study was to identify bony anatomic landmarks to predict the location of the anterior edge of the parotid gland to avoid injury to the facial nerve branches as they exit the parotid gland. The authors dissected 20 cadaver face halves to determine bony landmarks-the masseteric tuberosity and the inferior lateral orbital rim-to predict the location of the anterior parotid edge. Then they measured the anterior edge of the parotid gland in relation to the vector formed between these two bony landmarks. They identified and measured the most anterior portion of the parotid gland in relation to this vector. Then the most posterior aspect of the parotid gland in relation to this vector was measured. In the 20 dissections, the authors found the most anterior portion of the parotid gland to be 2.7 +/- 1.0 mm anterior to the vector from the inferior lateral orbital rim to the masseteric tuberosity. The most posterior part of the anterior edge of the parotid gland in relation to this vector was found to be 1.0 +/- 1.5 mm posterior to this vector. The parotid gland measured an average of 38.8 +/- 3.5 mm in width from the tragus to the anterior parotid edge. In elevating the SMAS with a face lift, the facial nerve branches can be predicted to exit the anterior edge of the parotid gland, which can be located 38.8 mm anterior to the tragus and near the vector from the inferior lateral orbital wall to the masseteric tuberosity.

The surgical management of facial nerve injury

Treatment of facial nerve injuries depends upon a detailed understanding of its anatomic course, accurate clinical examination, and timely and appropriate diagnostic studies. Reconstruction depends upon the extent of injury, the availability of the proximal stump. and the time since injury and duration of muscle denervation. Although no alternative is perfect, these techniques, in combination with static and ancillary procedures. can protect the eye, prevent drooling, restore the smile, and improve facial symmetry. New techniques (including single-stage free tissue transfers and bioengineered nerve grafts), further research on the characteristics of the facial musculature, and methods of preserving the neuromuscular junction will undoubtedly manifest themselves as further refinements of established surgical techniques.

Application of endoscope in zygomatic fracture repair

The endoscope has been used to visualise the upper face and brow in aesthetic facial surgery which is performed without a coronal incision. We applied these principles to repair zygomatic fractures with the aid of a 4 mm, 30 degree telescope inserted through a small temporal incision. Fracture sites at the zygomatic arch and the zygomaticofrontal suture were exposed and fixed with miniplates under endoscopic control. This technique was used in 15 consecutive patients including 2 with isolated zygomatic arch comminuted fractures and 13 having displaced zygomatic fractures with segmental, displaced zygomatic arch fractures. Nine patients were men and six patients were women with a mean age of 35 years. Three patients had associated mandibular fractures. The periods of follow-up ranged from 3 to 22 months. Two patients developed transient frontal nerve palsy which recovered within 2 months. One patient had mild temporal hollowing on the side of the facial fracture. All patients achieved the adequate anatomic reduction and satisfactory malar symmetry. There has been no case of chewing problems, cheek numbness or progressive enophthalmos developing postoperatively. Application of the endoscope in zygomatic fracture repair minimises the scalp scar, avoids forehead numbness, provides a comfortable postoperative recovery and shortens hospital stay. Careful preoperative evaluation and proper surgical technique are mandatory for achieving optimal results in selected patients.

Temporoparietal fascia: an anatomic and histologic reinvestigation with new potential clinical applications

Temporoparietal fascia constitutes a very important structural unit from both an aesthetic and a reconstructive surgical point of view. A histologically supported anatomic study was conducted for the reappraisal of the anatomic relationships and clinical application potentials of the data obtained. Anatomy of the temporoparietal fascia was investigated on 20 sides from 10 cadavers. After dissections, necropsies were obtained to demonstrate histologic features of the temporoparietal fascia. The outer part of the temporoparietal fascia is continuous with the superficial musculoaponeurotic system (SMAS) in the inferior border and with orbicularis oculi and frontalis muscles in the anterior border. Therefore, plication of the temporoparietal fascia can increase tightness of the SMAS, orbicularis oculi, and frontalis muscle in rhytidectomy. The frontal branches of facial nerve were noted to course parallel to the frontal branch of the superficial temporal artery, lying deeper to the temporoparietal fascia within the innominate fascia. In the view of these findings, conventional subfascial dissection, which is performed to protect frontal branches of the facial nerve, is not reasonable during the temporal part of rhytidectomy. Careful subcutaneous dissection just under the hair follicles is more appropriate to avoid nerve injury and also provides excellent exposure of the temporoparietal fascia for plication in rhytidectomy with protection of the auriculotemporal nerve and the superficial temporal vessels. Furthermore, two layered structures of the temporoparietal fascia are very suitable to insert a framework into the temporoparietal fascia for ear reconstruction to eliminate some of the shortcomings of Brent's technique. A thin muscle layer was also noted within the outer part of the temporoparietal fascia below the temporal line; the term "temporoparietal myofascial flap" would, therefore, be more accurate than "temporoparietal fascial flap." Finally, the innominate fascia and the deep temporal fascia can be elevated with the two layers of the temporoparietal myofascial flap to obtain a well-vascularized, four-layered myofascial flap based on the superficial temporal vessels. This multilayered flap can be used to reconstruct all defects when fine, pliable, thin, multilayered flaps are required.

Unilateral transient forehead paralysis following injury to the temporal branch of the facial nerve

BACKGROUND

Cutaneous surgery in the temporal region of the forehead can lead to injury to the superficial temporal branch of the facial nerve. A flattened forehead and with ipsilateral forehead paralysis can occur with damage to this nerve.

METHODS

A case is presented of transient forehead paralysis resulting from Mohs' micrographic surgery with reconstruction of the defect. The paralysis resolved over a period of fifteen months.

RESULTS

The anatomy of the nerve makes it susceptible to injury during cutaneous surgery. The area of danger is the area superior to the zygomatic arch and lateral to the lateral eyebrow where the nerve is closest to the skin.

CONCLUSIONS

Restoration of motor function usually occurs without intervention, but may take several months. Should motor function not recur, nerve grafting of a repair of the ptotic brow may be needed. The anatomy of the nerve is reviewed and brow lifting options are discussed.

Endoscopic malar/midface suspension procedure

Aging in the midface area is seen with ptosis of the malar tissues, hollowing of the infraorbital area, deepening of the nasolabial and mandibular labial folds, and increased jowling. Some of these aging changes are usually not corrected by a standard SMAS face lift. An endoscope-dependent technique was created specifically to address the midface area. The midface tissues are elevated and released in a subperiosteal manner and then suspended to a higher position after endoscopic dissection of the temporal area. The tissues are repositioned to a higher position on the malar area with softening of the nasolabial fold, decreased jowls, and recreation of the desired youthful fullness in the malar and infraorbital area. This procedure can be combined easily with other facial procedures such as rhytidectomy, neck lift, temple lift, and laser resurfacing when indicated. More than 200 procedures have been completed in the last 22 months. This report presents the surgical technique with early follow-up results.