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

Anatomical variations of the zygomaticofacial foramen and its related canal through the zygomatico-orbital and zygomaticotemporal foramina in dry human skulls

PURPOSE

The aim of this study is to reveal the location of the zygomaticofacial foramina, the variations of their numbers, and their connections between the zygomatico-orbital and zygomaticotemporal foramina.

METHODS

Ethics committee approval of our study was received by the Istanbul Medical Faculty Clinical Research Ethics Committee (date:30.07.2021, number:358356). 171 zygomatic bones of unknown gender from the Department of Anatomy, Istanbul University, were included in this study. The number of zygomaticofacial foramina and their connections with the zygomatico-orbital foramen and the zygomaticotemporal foramina were examined. Also, the morphometric distances between the zygomaticofacial foramen were calculated. Evaluation of the data was done with SPPS v.21.

RESULTS

The number of zygomaticofacial foramina was found as 299. It was found single, double, three, four, five and six foramina, in 52 (30.4%), 52 (30.4%), 24 (14.03%), 10 (5.85%), 5 (2.93%), 1 (0.58%) zygomatic bone, respectively. Zygomaticofacial foramen was absent in 27 (15.8%) bones. Of these 299 foramina, 129 were found to be connected with zygomatico-orbital foramen and 23 with zygomaticotemporal foramen. It was noted that 147 zygomaticofacial foramina had no connection with any foramina. The distances between the zygomaticofacial foramen and the frontozygomatic suture, temporal process, maxillary process, the lowest point of the zygomatic bone, and orbital rim were found as 25.30 ± 2.81mm, 18.74 ± 3.56mm, 21.56 ± 4.16mm, 18.72 ± 2.57mm, 6.67 ± 3.27mm, respectively.

CONCLUSION

Consequently, the location and variations of ZFF are of great importance for maxillofacial surgery and regional block anesthesia. Knowing its location and variations will help prevent complications during any surgical intervention in this region.

Liposuction of the Zygomatic Arch Area: A Novel Concept to Improve the Midface Contour

BACKGROUND

An ovoid, slender face with a smooth contour is preferred in oriental esthetics. We developed a novel concept to achieve a slimmer and harmonious midface contour by liposuction of the projection area of the zygomatic arch.

METHODS

A cadaver study including anatomical dissection and histologic examination were conducted to better understand the soft tissue structure of the projection area of the zygomatic arch and the vital technique for liposuction. For the clinical evaluation, 49 patients with midface hypertrophy who underwent liposuction of the zygomatic arch area from January 2016 to June 2021 were retrospectively reviewed.

RESULTS

Cadaver study showed that abundant fatty tissue existed in the subcutaneous layer of the zygomatic arch area. The liposuction manipulation was precisely limited to the subcutaneous fat layer, and nerve branches were observed in the deeper loose areolar tissue plane. Of the 49 patients enrolled in this study (including 98 zygomatic arch areas), the median fat removal volume per zygomatic arch area was 3.0 (2.0, 5.0) mL. The subcutaneous fat thickness was significantly decreased postoperatively [median 9 (6, 10) mm vs. 1 (1, 2) mm per zygomatic arch area, P < 0.001]. All patients were satisfied with their postoperative outcomes. Only three patients underwent slight depression of the liposuction area during making facial expression after surgery and subsequently recovered.

CONCLUSIONS

Liposuction of the zygomatic arch area is effective in improving midface hypertrophy and achieving a harmonious facial contour with a low risk of complications.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Microanatomy of the Frontal Branch of the Facial Nerve: The Role of Nerve Caliber and Axonal Capacity

BACKGROUND

A commonly seen issue in facial palsy patients is brow ptosis caused by paralysis of the frontalis muscle powered by the frontal branch of the facial nerve. Predominantly, static methods are used for correction. Functional restoration concepts include the transfer of the deep temporal branch of the trigeminal nerve and cross-facial nerve grafts. Both techniques can neurotize the original mimic muscles in early cases or power muscle transplants in late cases. Because axonal capacity is particularly important in cross-facial nerve graft procedures, the authors investigated the microanatomical features of the frontal branch to provide the basis for its potential use and to ease intraoperative donor nerve selection.

METHODS

Nerve biopsy specimens from 106 fresh-frozen cadaver facial halves were obtained. Histologic processing and digitalization were followed by nerve morphometric analysis and semiautomated axon quantification.

RESULTS

The frontal branch showed a median of three fascicles (n = 100; range, one to nine fascicles). A mean axonal capacity of 1191 ± 668 axons (range, 186 to 3539 axons; n = 88) and an average cross-sectional diameter of 1.01 ± 0.26 mm (range, 0.43 to 1.74 mm; n = 67) were noted. In the linear regression model, diameter and axonal capacity demonstrated a positive relation (n = 57; r2 = 0.32; p < 0.001). Based on that equation, a nerve measuring 1 mm is expected to carry 1339 axons.

CONCLUSION

The authors' analysis on the microanatomy of the frontal branch could promote clinical use of cross-facial nerve graft procedures in frontalis muscle neurotization and free muscle transplantations.

Safe Zone for Dissection in Frontotemporal Region to Avoid Injury to the Temporal Branch of Facial Nerve

ABSTRACT

The objective of this study is to provide a reliable roadmap for temporal branch of the facial nerve, in order to minimize, the risk of injury to the nerve during surgical dissections. A literature search was conducted on temporal branch of facial nerve. The date search range was 1950 to 2017. Databases searched included Medline, Web of science, Biosis, SciELO, Data Citation, and Zoologic Records. Data were collected on, author specialty, date of publication, and the relationship of the temporal branch of facial nerve to various landmarks in the frontotemporal region reported in human anatomic studies. Among the 48 studies reviewed, a total of 3477 anatomic dissections were performed in the craniofacial region. Temporal branch of facial nerve was located between 2.5 and 3 cm from lateral orbital rim. In relation to the zygomatic arch, it was found anywhere from the midpoint of the arch to 1 finger breath posterior to the arch. For the plane, it was most commonly described as being under the superficial temporal fascia (STF) or within the loose areolar tissue. Most anatomic dissections found 2 to 4 twigs of the temporal branch of facial nerve. In relation to the lateral canthus, it was found to be 2.85 +/- 0.69 cm superior and 2.54 +/- 0.43 cm lateral to the lateral canthus. Our study suggests consolidated data on surgical landmarks in order to ensure safe dissection in temporal region and prevent injury to the temporal branch of facial nerve.

Distribution of the Laterally Supplying Facial Nerve to the Orbicularis Oculi Muscle

BACKGROUND

The facial nerve that traverses the lateral border of the orbicularis oculi muscle is considered the primary motor for the muscle. Nevertheless, the lateral motor supply to the orbicularis oculi muscle has not yet been fully described.

OBJECTIVES

The aim of this study was to report detailed anatomic information about the lateral motor supply route to the orbicularis oculi.

METHODS

Facial nerve branches that cross the lateral orbicularis oculi border were fully traced from the parotid border to the nerve destinations in 43 fresh hemifaces by microscopic surgical dissection and time-lapse photography.

RESULTS

Through the lateral route, the anterior temporal and upper zygomatic branches supply the superior orbital and superior preseptal orbicularis oculi of the upper eyelid, as well as the lateral pretarsal and malar orbicularis oculi, excluding the upper medial pretarsal portion of the upper eyelid and most of the lower eyelid. The nerve supplying the lateral pretarsal orbicularis oculi muscle crosses the anterior area of the zygomatic arch. It then traverses an area 6 mm above and 4 mm below the lateral canthal crease.

CONCLUSIONS

The anterior area of the zygomatic arch and an area 6 mm above and 4 mm below the lateral canthal crease are the facial nerve danger zones. The present anatomic findings provide surgeons with further insights for performing blepharoplasty, midface lift, facelift, and facial nerve reconstructive surgery.

Facial Nerve Injury and Repair: A Practical Review for Cutaneous Surgery

BACKGROUND

The facial nerve and its branches are at risk of injury during dermatologic surgery. Few publications in the dermatologic literature discuss facial nerve injury and management.

OBJECTIVE

To review facial nerve injury and management, including static and dynamic repair techniques, and to review outcomes in facial nerve reconstruction.

METHODS

Two detailed literature reviews were performed using PubMed. First, articles reporting facial nerve injury and/or management in the dermatologic literature were identified. In addition, articles pertaining to outcomes in facial nerve reconstruction with a minimum of 20 patients were included.

RESULTS

Fifty-three articles reporting outcomes in facial nerve reconstruction were identified and consist of retrospective reviews and case series. Most patients achieve improvement in facial symmetry and movement with nerve repair.

CONCLUSION

Timing of facial nerve repair is an important consideration in management of facial nerve injury, with earlier repairs achieving better outcomes. Facial nerve repair does not result in normal facial movement, and improvements may require a year or more to be realized. Many options exist for facial nerve reconstruction, and patients with long-standing facial nerve injuries may still benefit from treatment.

"Radiological morphometric analysis of the zygomatic arch: Application of osteosynthesis on the upper arch border for rigid fixation"

BACKGROUND

This study was designed to introduce a novel method of applying osteosynthetic materials to the upper zygomatic arch border for fracture fixation through a temporal incision, and analyze the radiologic morphometric dimensions of the arch to verify its validity.

METHODS

Radiological morphometry was analyzed in 51 adult patients with unilateral isolated zygomatic arch fractures. Frequent fracture sites, sites of minimal thickness and height, and their correlation were evaluated, as were the locations and dimensions of fixation vantage points. The novel surgical method based on the results was implemented in 17 clinical cases.

RESULTS

Frequent fracture sites, occurring 4.40, 16.47 and 30.48 mm posterior to the arch origin, did not correlate to sites of minimal height and thickness. Arch minimal thickness and height locations were 12.23 and 27.09 mm behind its origin, respectively. Fixation vantage point dimensions varied from point to point, with upper thickness ranging from 1.67 to 4.86 mm and mid-portion thickness ranging from 2.06 to 7.36 mm, and height ranging from 8.99 to 22.53 mm. Arch vertical axis inclination ranged from 6.51° to 16.47°, which increased as the arch stretches posteriorly. These results suggested the use of 1.5 mm-wide plates and 1 mm-diameter screws with 6-8 mm length. Patients received surgery based on these morphometry results for satisfactory stabilization.

CONCLUSIONS

This study introduces a new method for open reduction and internal fixation of arch fractures, with morphometric analysis of the arch verifying the validity of tangential plate application to the upper border.

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.

The sentinel fat pads: the relationship of the ROOF and SOOF to the temporal nerve in facial rejuvenation

BACKGROUND

A great number of studies have reported on the temporal branch anatomy and its relationship to the fascial layers and various fat pads of the temporal region, but no article has included information on the relationship of the temporal nerve to the retro-orbicularis oculi fat (ROOF) and/or the suborbicularis oculi fat (SOOF).

OBJECTIVES

The authors report the results of a series of human cadaver temporal nerve dissections, with particular attention paid to its relation to the ROOF and the SOOF. The results of a literature review and a subsequent open browlift are also reported to confirm the results of the cadaver study.

METHODS

Dissection was performed on 15 fresh human cadavers, for a total of 29 hemifaces. The course and relationships of the temporal nerve branch to the fascia, fat pads, and landmarks in the temporal region were noted and detailed. A thorough review was also performed for 23 articles, to compare the author's anatomical findings with data in the previous literature.

RESULTS

During cadaver dissection, the temporal branch was found to lie on the undersurface of the superficial temporal fascia. In the supraorbital area, the ROOF existed in the loose areolar plane or deep layer of the superficial temporal fascia, with the temporal nerve branch directly superficial to it. The temporal branch passed lateral to the SOOF in its superiomedial course at the level of the zygoma. These findings were later confirmed during an in vivo open browlift as well.

CONCLUSIONS

The ROOF was formerly unrecognized as an important sentinel marker for possible injury to the temporal nerve branch during browlift. However, this cadaver study and its accompanying literature comparisons show that browlift dissection, whether endoscopic or open, should aim to keep the ROOF fat in the superficial plane, ensuring that the nerve branch is safe from iatrogenic injury.