Mitigating facial nerve injury risks in aesthetic surgery: A narrative review of surgical practices and anatomicsal challenges

Abstract

Facial nerve injuries pose challenges in cosmetic surgery. We comprehensively reviewed the anatomy of the facial nerve, with a focus on its five major branches—temporal, zygomatic, buccal, marginal mandibular, and cervical— and explored the clinical implications of nerve injuries during cosmetic procedures. Surgical damage to any branch of the facial nerve can lead to functional impairments, including facial asymmetry, impaired eye closure, speech difficulties, and reduced oral competence. Furthermore, aesthetic consequences, including facial drooping and altered appearance, can profoundly affect patients' psychological well-being. This review provides a detailed discussion of strategies for preventing nerve injury, including surgical techniques and landmark identification that underscores the importance of meticulous preoperative planning and intraoperative execution. This review highlights the importance of comprehensive anatomical knowledge in optimizing patient safety and satisfaction in facial cosmetic surgery.

Introduction

The facial nerve, cranial nerve VII, a critical structure in the human body with sensorimotor components, plays a pivotal role in facial expressions, taste, and various autonomic functions.¹ The facial nerve comprises motor fibers that control facial muscles, parasympathetic fibers that manage secretomotor functions of the salivary and lacrimal glands, and sensory fibers for taste sensations from the anterior two-thirds of the tongue and cutaneous sensations from the external ear.² Owing to its central role in several physiological processes, facial nerve injury induces significant functional impairments and psychologic distress that lower the quality of life.³

The facial nerve is particularly important in oral and ocular physiology, and surgical damage is associated with foreign-body sensation and blurry vision in nearly 54 % and 50 % of patients, respectively.3, 4, 5 Although permanent facial nerve injuries occur rarely, transient neuropraxia, following electrocautery or mechanical traction, occurs more frequently.⁶ Given the cosmetic and functional importance of the structures innervated by the facial nerve, its significance in clinical practice, particularly in cosmetic surgery, cannot be overstated. Surgeons must have a detailed understanding of facial nerve anatomy and its potential variations to minimize the risk of injury during facial procedures. This review highlights the anatomical variations, key landmarks, and clinical relevance of the main branches of the facial nerve, discusses strategies to prevent surgical nerve damage, and provides a comprehensive overview to support improved surgical outcomes.

Anatomy of the facial nerve

The facial nerve originates at the pontomedullary junction of the pons and comprises two main parts: the proper facial nerve, responsible for motor function, and the intermediate nerve, which carries sensory and parasympathetic fibers.⁷ It exits the brainstem and enters the internal acoustic meatus, traveling alongside the vestibulocochlear nerve (CNVIII).⁸ After traversing the facial canal, the nerve bends at the geniculate ganglion, giving off branches including the greater petrosal and stapedius nerves.^9,10 Within the facial canal, the facial nerve carries taste fibers from the anterior two-thirds of the tongue and parasympathetic fibers to the submandibular and sublingual glands.¹¹

After exiting the facial canal and skull via the stylomastoid foramen, the facial nerve innervates the posterior belly of the digastric and stylohyoid muscles before entering the parotid gland, where it divides into five terminal branches: temporal, zygomatic, buccal, marginal mandibular, and cervical (Figure 1).¹² The Davis classification system categorizes the branching patterns of the facial nerve within the parotid gland, based on the presence and location of anastomoses between its divisions,¹³ into four types: Type I, no anastomoses between branches; Type II, anastomoses are confined to the temporofacial division; Type III, a single anastomosis between the temporofacial and cervicofacial divisions; and Type IV, a complex pattern with multiple anastomoses between divisions, frequently accompanied by variations in branch origin and distribution. This classification helps surgeons anticipate anatomical variations and minimize surgical risk (Figure 2).

Figure 1.

Branches of the facial nerve. This figure illustrates the facial nerve following its emergence from the stylomastoid foramen. The dissection reveals the nerve's branching pattern within the parotid region, including its temporal, zygomatic, buccal, marginal mandibular, and cervical branches. The nerve was infiltrated with indocyanine green (ICG) dye and imaged under black light to highlight the anatomical distribution of the five branches. (a) Original dissection image. (b) Annotated view showing the branching paths of the facial nerve for clarity. A. Temporal branch; B. Zygomatic branch; C. Buccal branch; D. Marginal mandibular branch; and E. Cervical branch.

Figure 2.

Davis Distribution of the branches of the facial nerve. This figure demonstrates the six patterns of facial nerve branching within the parotid region, as classified by Davis. Each panel (types I–VI) represents a unique anatomical variation in the distribution of the temporofacial (green) and cervicofacial (purple) divisions of the facial nerve. (a) Displays the course of the facial nerve through the parotid gland. (b) Illustrates the different patterns of connections between the nerve branches.

Temporal branch

The temporal branch is the most superior division of the facial nerve that courses through the parotid gland, over the zygomatic arch, and toward the temporal region of the scalp. It innervates the frontalis, superior portion of the orbicularis oculi, and corrugator supercilii muscles, thereby contributing to eyebrow movement, eyelid closure, and frowning.^14,15

To minimize injury, several anatomic landmarks aid in defining a “safe zone” for temporal branch preservation. Davies et al. identified the porion—a fixed bony point at the upper border of the external auditory meatus—as a reliable posterior landmark; a line drawn 12 mm anterior to it (the Porion Line) accurately marks the posterior boundary of the temporal branch distribution.¹⁶ Anteriorly, the zygomaticotemporal and frontozygomatic sutures define the Zygomatic Sutural Line, completing the anatomic framework for surgical planning.¹⁶ Radiologic references such as the supraorbitomeatal and infraorbitomeatal lines offer further refinement. While Pitanguy’s line (0.5 cm below the tragus to 1.5 cm above the lateral eyebrow) has been widely used, its reliance on soft tissue landmarks makes it more prone to interindividual variation.¹⁶

Sanderson et al. proposed a reliable method for locating the temporal branch using two consistent bony landmarks: the apex of the tragus and the zygomatic arch.¹⁷ The temporal branch crosses the inferior zygomatic arch approximately 3.21 ± 0.05 cm anterior to the tragal apex, which serves as a stable reference with minimal interindividual variation. The zygomatic arch, easily palpable and anatomically consistent, provides a second key landmark, as the nerve runs superficially over it—making it especially vulnerable during facial surgery.¹⁷ Sanderson further noted that Pitanguy’s line is less accurate due to eyebrow variability, with the temporal branch crossing the arch on average 0.34 ± 0.09 cm anterior to this line, reinforcing the value of bony landmarks over soft-tissue cues.¹⁷

However, anatomical variation in the number and course of temporal branch divisions increases the risk of injury.¹⁸ Some branches run more superficial or deeper than expected. Pankratz et al. identified a “caution zone” where the nerve becomes more superficial—9.6 mm above the arch and 12.2 mm posterior to Pitanguy’s line—as it transitions from a sub-SMAS to an intra-SMAS plane, a critical area to avoid during SMAS rhytidectomy and similar procedures (Figure 3).¹⁹

Figure 3.

Injury to the temporal branch following a linear laceration. This figure depicts a surgical exposure of a temporal branch injury that was caused by a linear laceration extending across Pitanguy's line (indicated in purple). The surgical approach highlights the anatomical relationship of the temporal branch in proximity to Pitanguy's line, and emphasizes its vulnerability in facial trauma. (a) The laceration prior to the nerve repair highlights the severed temporal branch within the wound bed. (b) Appearance of the laceration after injury nerve repair demonstrates the re-anastomosis of the affected nerve branch.

Temporal branch injury primarily affects forehead and eye muscles, leading to difficulty raising the eyebrow, wrinkling the forehead, and fully closing the eye (lagophthalmos).²⁰ Functionally, the inability to close the eye completely can result in exposure keratopathy and long-term damage secondary to corneal dryness. Aesthetically, the loss of forehead movement causes an asymmetrical appearance, with the affected side of the forehead appearing smooth and flat. Eyebrow ptosis on the affected side may contribute to a sagging appearance.²¹ Gao et al. conducted a single-center retrospective review of 93 patients who underwent reduction malarplasty and found that 4.3 % (4 patients) developed transient temporal branch injury at 1 week after surgery, presenting with loss of forehead lines and impaired eyebrow lifting, while eyelid closure was preserved.²²

Zygomatic branch

The zygomatic branch exits the parotid gland just inferior to the temporal branch and courses along the zygomatic bone, near the lateral aspect of the orbit, deep into the zygomaticus major muscle. This branch is commonly divided into superior and inferior branches. The superior branch typically courses toward the orbicularis oculi muscle, particularly around the lateral canthus of the eye, and plays a key role in eyelid closure and blinking. The inferior branch extends toward the zygomaticus major and minor muscles, which elevates the lips and contributes to facial expressions such as smiling.¹⁴

Saylam et al. conducted a cadaveric dissection study of 66 specimens from 33 adult cadavers, in which superficial tissues were removed to identify the zygomatic branches of the facial nerve and their anatomic relationships with the parotid gland, tragus, and lateral palpebral commissure, and found that the zygomatic branch typically emerges from the anterior border of the parotid gland. The mean horizontal distance between the tragus and the point where the uppermost zygomatic branch exits the parotid gland was approximately 30.7 mm, although this distance ranged from 16.2 to 45.6 mm.²³ This study provides detailed morphometric data that can guide localization of the zygomatic branches during surgery.

Saylam et al. identified an oblique line from the tragus to the lateral palpebral commissure as a reliable landmark for locating the path of the zygomatic branches, which are almost always located beneath this line. The average vertical distance from the midpoint of this oblique line to the uppermost zygomatic branch is 19.29 mm, ranging from 5.70 to 28.72 mm.²³ This measurement helps surgeons assess the depth at which nerve branches can be located. Kehrer et al. also highlighted Zuker's point—located midway between the root or "crux" of the ear helix and the oral commissure serving as a marker for locating, within 5 mm, the zygomatic branch; this anatomic landmark is particularly useful in facial reanimation procedures.²⁴

The zygomatic branch exhibits several important anatomical variations critical for surgical planning. Saylam et al. noted that most individuals (69.7 %) have two zygomatic branches while 25.8 % have three, and 4.5 % have only one. In rare cases, the zygomatic branch forms a common trunk with the buccal branches of the facial nerve. Furthermore, the inferior branch of the zygomatic nerve may form a zygomaticobuccal plexus with the buccal branches, a relationship observed in 9.1 % of the cases.²³ From a surgical standpoint, these variations underscore the importance of cautious dissection in the lateral midface, particularly when performing procedures such as facelifts, blepharoplasty extensions, or zygomatic arch reduction, where inadvertent injury can result in functional and aesthetic deficits. The branch may also vary in depth, running superficially beneath the skin–making it more vulnerable–or deeper along or below the zygomatic arch. This relationship with the zygomatic arch is often classified into three types: directly on or below the arch, 1 − 2 cm below it, or >2 cm below it, which affects its surgical accessibility.²⁵ For surgeons, recognizing these depth variations informs the choice of dissection plane, favoring a more conservative sub-SMAS approach in high-risk areas, and highlight the need for meticulous, layered dissection to preserve nerve integrity.

Injury to the zygomatic branch has distinct clinical features. A hallmark symptom is lagophthalmos, incomplete eyelid closure, secondary to the paralysis of the orbicularis oculi muscle. This can lead to corneal exposure, ulceration, infection, and chronic irritation. Loss of muscle function in the zygomatic region results in noticeable facial asymmetry, with the affected side appearing drooped or less mobile.²⁶ As the zygomatic branch plays a key role in smiling, damage to this nerve can impair facial movements, and thus affect communication and social interactions. In severe cases, upper lip movement may be impaired, which makes speech articulation and eating challenging. Paralysis can cause the lower eyelid to sag, which further exacerbates eye exposure and aesthetic concerns.²⁷ In a retrospective observational study of 215 patients(247 operative procedures) undergoing external dacryocystorhinostomy, 16 (7.4 %) experienced zygomatic branch injury, presenting with lagophthalmos, which generally resolved over several months; the study provides valuable clinical insight, however, its retrospective design, reliance on chart review, and the limited mean follow-up time of 20 weeks (range 3 to 50 weeks) limit the strength and generalizability of the findings.²⁸

Buccal branch

The buccal branch, most often the largest branch of the facial nerve, travels horizontally across the face, emerging from the anterior aspect of the parotid gland and coursing either over or just beneath the superficial fascia of the masseter muscle. The buccal branch typically courses inferior to the parotid duct; however, it can also run parallel to or even cross the parotid duct to reach the buccal region of the face.²⁹ The buccal branch innervates several muscles involved in facial expressions, including the buccinator muscle, which controls cheek tension during activities, such as blowing and chewing,³⁰ and supplies the orbicularis oris, which is responsible for lip puckering, and the levator labii superioris and levator anguli oris, which elevate the upper lip.³¹

The buccal branch is closely associated with key midface landmarks. Saylam et al. identified the parotid duct (Stensen duct) as a critical reference, with the buccal branch typically passing either superior or inferior to it at a mean distance of 6.68 ± 5.06 mm.³² It usually emerges from the anterior border of the parotid gland about 35.62 ± 7.11 mm from the tragus, and reliably travels below a line drawn from the tragus to the ala nasi—making these landmarks valuable guides for avoiding nerve injury during midface and parotid surgery.³² Anatomical variations in the branch–duct relationship are categorized into four types: Type I (35 %)—a single branch passing inferior to the duct; Type II—passing superiorly; Type III—forming a plexus with adjacent branches such as the zygomatic or marginal mandibular (26.7 %); and Type IV—two separate branches passing both superior and inferior to the duct (13.3 %).³²

Tsai et al. conducted an anatomic cadaveric study of 35 adult Taiwanese hemifaces, excluding specimens with facial defects, and reported that the branches of the buccal nerve could cross over Stenson's duct at between 1 and 5 distinct points. They analyzed the anatomic relationship between the point of emergence of the buccal branches of the facial nerve and that of Stenson's duct along the anterior border of the parotid gland. They reported that the most superior branch of the buccal nerve emerges 9.58 ± 5.68 mm superior to Stenson's duct, and that the most inferior branch of the buccal nerve emerges 11.03 ± 5.38 mm inferior to Stenson's duct along the anterior border of the parotid gland.³³ Common anatomical variations include the number of buccal branches, which can range from a single dominant branch to multiple branches (typically, two to six). These branches may arise separately from the main trunk of the facial nerve or as a common stem before subdividing into smaller branches.³⁴ The presence of multiple buccal branches increases surgical complexity, as each branch must be carefully identified and preserved to maintain facial function.

Injuries to the buccal branches frequently cause weakness of the muscles that control the upper lip and cheek, leading to drooping and decreased mobility.³⁵ Patients may experience difficulty with movements such as smiling and showing their teeth, incomplete mouth closure, articulation, and an inability to puff their cheeks. These deficits can cause functional impairments, such as difficulty in pronouncing bilabial sounds with "P," "B," and "M," as well as issues associated with chewing, eating, and drooling.³⁶ Aesthetically, facial asymmetry is most frequently apparent during smiling, with a flattened or expressionless appearance on the affected side, which can contribute to social and psychological distress.³⁷ Pelster et al. reported a patient with buccal nerve injury after Mohs surgery who experienced weakness in the upper lip and left oral commissure without resolution at the 2-month follow-up.³⁵

Marginal mandibular branch

The marginal mandibular branch of the facial nerve exits the parotid gland at its lower anterior border and courses inferoanteriorly along the mandibular margin, typically traveling superficial to the facial artery and vein but deep to the platysma before curving upward toward the chin.³⁸ Despite some interindividual variation, it reliably innervates the depressor anguli oris, depressor labii inferioris, and mentalis muscles, which contribute to lower lip movement and expressions such as sadness and pouting.³⁹

Hazani et al. conducted a cadaveric dissection study of 18 facial halves using loupe magnification to identify key anatomical landmarks for avoiding surgical marginal mandibular nerve (MMN) injury. The masseteric tuberosity, located at the mandibular angle, serves as a primary reference point, and the MMN crosses the facial artery approximately 3 cm anterior to the tuberosity along the mandibular border, which constitutes a reliable intraoperative guide. The facial artery is a crucial landmark, as the MMN passes superficial to it at the lower mandibular border. The distance from the masseteric tuberosity to the mental midline is 11.3 cm, with the MMN positioned nearly 3 cm from the tuberosity, and provides another consistent reference. The inferior mandibular border is a key landmark, as the MMN follows this margin, and courses deep within the masseteric fascia after exiting the parotid gland.⁴⁰ This study provides precise morphometric data useful for surgical planning, though its small cadaveric sample limits generalizability to live patients.

Kannan et al. (2024) identified the first submental artery perforator (SMAP) as a reliable landmark for locating the MMN.⁴¹ Positioned 2 cm below the mandibular border and 2–3 cm anterior to the platysma’s posterior edge, the first SMAP consistently aligns with the MMN, which aids nerve identification during facelifts and neck dissections. Preoperative Doppler imaging improves surgical precision by mapping the location of first SMAP, around which the MMN frequently loops. Intraoperative nerve stimulation further confirms the MMNs identity by verifying its branches to the depressor anguli oris and labii inferioris.⁴¹

Hazani et al., through cadaveric dissection, identified key anatomical variations of the MMN that increase the risk of iatrogenic injury. In 19 % of cases, the nerve dips ≤1 cm below the mandibular border, rather than remaining above it—particularly relevant in patients with lax or atrophic tissues.⁴⁰ Additionally, the MMN may bifurcate near the facial artery in 22 % of cases, complicating its dissection.⁴⁰ While it typically exits the parotid gland above the mandible, variants may exit below and course across the posterior belly of the digastric and submandibular gland, increasing susceptibility to injury. The nerve usually crosses the facial artery ∼3 cm anterior to the masseteric tuberosity, but this relationship also varies, underscoring the importance of individualized surgical planning.⁴⁰

MMN injuries confer several distinct clinical symptoms of which the most common are drooping and difficulty in controlling the lower lip on the affected side, owing to paralysis or weakness of the depressor labii inferioris muscle. The innervation of the chin muscles makes the affected side appear less responsive or stiff during facial expressions. Functional impairments include difficulty eating and drinking, drooling – particularly during oral intake – and speech impairment. Aesthetic consequences include facial asymmetry and smile deformity.⁴² Sugeeth et al. conducted a prospective longitudinal study of 48 patients who all underwent submandibular procedures during a single year at a tertiary care hospital. They reported a 12 % incidence of marginal mandibular nerve injury following submandibular procedures; the affected patients exhibited lower lip droop, impaired oral continence, slurred speech, and facial asymmetry (Figure 4).⁴³ While this study provides clinically relevant incidence data, its small sample size and single-center design limit the generalizability of the findings.

Figure 4.

Facial asymmetry following injury to the marginal mandibular branch. This figure demonstrates the clinical presentation of facial asymmetry and drooping of the right side of the face following an injury to the marginal mandibular branch of the facial nerve. The image highlights the characteristic inability to elevate the lower lip on the affected side, which results in an uneven smile.

Cervical branch

The cervical branch emerges inferior to the parotid gland and travels 1–2 cm below the mandibular border within the superficial fascia of the neck. As it descends, the nerve travels within the subcutaneous tissue, superficial to the deep cervical fascia and deep to the platysma muscle, crosses the submandibular triangle, and may pass adjacent to the angle of the mandible or descend slightly inferior to it.⁴¹ The cervical branch primarily innervates the platysma muscle, which plays a key role in depressing the lower lip and tautening the skin of the neck. These actions are important for facial expressions of fear and tension, besides practical movements, such as tightening the skin of the neck.¹

Chowdhry et al. (2010) dissected 16 fresh heminecks using loupe magnification to identify key anatomical landmarks for locating the cervical branch of the facial nerve and reported that the cervical branch point was typically located 1 cm inferior to a perpendicular line constructed at the mandibular angle along the mastoid–mentum line. They further determined that the branching point is situated 1.75 ± 0.26 cm below this perpendicular reference line, providing a consistent anatomical landmark for identifying and preserving the cervical branch during surgical procedures.⁴⁴

Ziarah and Atkinson described the cervical branch as coursing posterior to the mandibular branches without crossing the mandible, located approximately 0.83 cm (range 0.2–1.4 cm) posterior to the gonion. It runs deep to the platysma and superficial to the outer lamina of the deep cervical fascia, forming a fine plexus near the hyoid bone, creating a recognized “danger zone” between the mandible and hyoid. In 80 % of cases, a single branch emerges from the parotid, while in 20 %, two parallel branches form a plexus near the submandibular gland.⁴⁵ Although the cervical branch rarely anastomoses with the mandibular branch, frequent communications with the transverse cervical and great auricular nerves are observed, particularly near the greater cornu of the hyoid. Familiarity with these anatomical relationships is essential to avoid inadvertent nerve injury.

Injuries to the cervical branch induce weakness or paralysis of the platysma, which impairs specific neck movements, such as tautening the skin of the neck.³ Although the cervical branch plays a minor role in lower facial expression and facial symmetry, this nerve damage can have subtle aesthetic consequences that include sagging of the neck owing to flaccid skin, loss of jawline definition resulting in a more rounded facial appearance, and the development of prominent platysmal bands, contributing to a wrinkled or banded neck contour.⁴⁶ In a single surgeon study, Daane et al. analyzed 2002 patients who underwent SMAS platysma facelifts and reported a 1.7 % incidence of cervical branch injuries.⁴⁷ Affected individuals experienced symptoms, such as transient lip depressor dysfunction, asymmetry in facial expressions, difficulty in fully depressing the corner of the mouth, and a distorted smile. Notably, all patients in the study cohort achieved complete recovery of function after 6 months.

Cosmetic surgeries and potential complications

Facial nerve injury is a known complication of facial cosmetic surgery, most often due to direct trauma, stretching, or transection.⁴⁸ Facelifts and brow lifts carry the highest risk given their proximity to key nerve branches.⁴⁹ Injuries may result from sharp dissection, excessive tension, or poor technique, including improper instrument positioning.⁵⁰ Each procedure carries unique risk based on its anatomical location (Table 1 and Figure 5).

Table 1.

Measures to prevent facial nerve injury in common cosmetic surgeries.

	Useful landmarks	Dissection	Surgical techniques
Facelift	Sentinel vein Zygomatic arch Parotid duct	Zygomatic and Buccal: Dissect 5 mm above the upper masseteric ligaments Mandibular: Superficial to the platysma-SMAS Cervical: Ensure subplatysmal dissection at the mandibular angle; avoid sub-SMAS fat penetration	Avoid excessive ligament release Use blunt dissection near nerves Stay superficial to the temporoparietal fascia Limit cautery
Brow Lift	45° RL from the lateral canthus Red Zone: 2 cm superolateral to the brow Supratrochlear and supraorbital foramina	Incision ≤3 cm from the lateral canthus along the RL Avoid deep dissection in the Red Zone	Minimize trauma in high-risk zones Use caution near zygomatic bone and the infraorbital rim Gentle retraction
Eyelid surgery	1–2 mm crease below the lash line	Keep dissection superficial to protect medial orbicularis motor line Avoid deep dissection at the medial palpebral corner Maintain superficial submuscular dissection in the lateral lower eyelid Limit pretarsal orbicularis oculi dissection	Preserve nerve integrity with careful handling Avoid excessive tension on tissues
Neck lift	Gonion SCM muscle Submandibular gland	Avoid penetrating the platysma or aggressive liposuction Limit lateral dissection to protect delicate CBFN branches	Maintain superficial subplatysmal plane Use blunt-tip scissors with vertical spreading

This table outlines specific anatomical landmarks that are crucial for minimizing the risk of facial nerve injury during common cosmetic surgeries, including facelifts, brow lifts, eyelid surgeries, and neck lifts. The table presents critical anatomical considerations and surgical techniques to ensure optimal surgical outcomes and nerve preservation.

Figure 5.

Illustration of the facial nerve branches with associated injury rates for various cosmetic surgeries. The figure shows the primary divisions of the facial nerve as follows: temporal, zygomatic, buccal, marginal mandibular, and cervical branches. Each branch is annotated based on the percentage of injury risk during specific cosmetic procedures.

Facelift (Rhytidectomy)

Facial nerve injury during facelift surgery occurs rarely but has considerable functional and aesthetic consequences. Each branch of the facial nerve carries a varying level of risk, with the temporal branch being particularly vulnerable owing to its superficial course.⁵¹ Cadaveric and clinical studies show variable depth transitions of the frontal branch across the zygomatic arch and relative to Pitanguy’s line; safe dissection respects the parotid-temporal fascia and high-SMAS principles.19, 52, 53, 54 Overall injury rates are as high as 2.6 %, although most cases resolve within 6 months.⁵⁵ Injury rates of the buccal and zygomatic branches range from <0.23 % to 1.08 %, with most cases being transient and clinically insignificant.⁵⁶ The marginal mandibular has a reported injury incidence of 0.51 %; however, the risk of permanent damage is higher approximately 0.1 %, owing to limited nerve arborization. The cervical branch is also susceptible, although injuries generally induce minimal clinical impact.

Multiple systematic reviews and meta-analyses encompassing over 15,000 patients report low rates of permanent nerve injury across SMAS facelift techniques, with pooled estimates ranging from <0.05 % to 0.39 %.56, 57, 58 Temporary nerve injury remains the most common complication, occurring more frequently with high lateral SMAS (1.85 %) and composite rhytidectomy (1.52 %) compared to SMAS plication (OR = 2.71 and 2.22, respectively; P < 0.05).⁵⁷ These findings support the overall safety of SMAS techniques, though complication profiles vary by approach.

While facelift-specific data on surgeon volume or experience are limited, large multi-institutional studies suggest that supervised resident participation does not increase complication rates in outpatient aesthetic procedures.59, 60, 61 Additionally, although overall complication rates do not consistently differ by technique when executed properly, the dissection plane determines which nerves are at risk.61, 62, 63

Brow lift (Forehead lift)

Browlift procedures carry a risk of temporal branch injury, particularly with coronal approaches involving subperiosteal dissection, which have a 6.4 % motor nerve injury rate.⁶⁴ Endoscopic techniques present a lower risk (∼1.5 %), while subgaleal approaches show minimal nerve injury. Overall, the likelihood of injury depends on both incision type and dissection plane.

A 2025 meta-analysis of 22 studies (2127 brows; mean follow-up 20.9 months) reported that persistent motor deficits after brow lift are rare, though sensory disturbances—particularly with tined implant fixation—are more common.⁶⁵ Another 2025 meta-analysis focused on endoscopic brow lifts found temporal branch injury rates typically under 2 %, reinforcing that such injuries are more often associated with coronal approaches.⁶⁶

Smoking and hypertension are key patient-level risk factors for perioperative complications in facial aesthetic surgery, whereas age alone is not consistently predictive. In fact, one multivariable analysis of combined endoscopic brow lift and blepharoplasty found that increasing age was associated with slightly lower odds of complications.⁶⁷ Prior brow or eyelid surgery may complicate revision lifts by distorting anatomic planes, though secondary endoscopic lifts after coronal approaches remain feasible with comparable complication rates, provided cautious dissection is performed.⁶⁸

Blepharoplasty (Eyelid surgery)

Blepharoplasty, especially lower eyelid surgery, confers a risk of facial nerve injury. The zygomatic and buccal branches of the facial nerve are the primary nerves at risk. Turin et al., in a retrospective review of 150 consecutive patients undergoing a limited incision lateral brow lift combined with upper blepharoplasty by a single surgeon, reported two cases (1.3 %) of temporal branch injuries in 150 blepharoplasty procedures, all of which fully resolved. These findings suggest that while the procedure carries a low risk of transient nerve injury, it remains a safe and effective approach; however, its single-surgeon, retrospective design and lack of long-term follow-up may limit generalizability and the assessment of rare complications.⁶⁹ Our review did not identify any systematic reviews or meta-analyses focused specifically on facial nerve injury rates in blepharoplasty, underscoring a gap in the high-level evidence. Postoperative signs of nerve injury, such as asymmetrical blinking or incomplete eyelid closure, should prompt early intervention. Physical therapy and other rehabilitative measures can facilitate functional recovery and minimize long-term complications.⁷⁰

Evidence directly tying surgeon experience, patient age, or prior surgery to facial-nerve injury after blepharoplasty is sparse: reviews note learning-curve considerations but report no nerve-specific rates, and revision series likewise lack motor-nerve injury rates.71, 72, 73, 74

Neck lift (Cervicoplasty)

The rate of facial nerve injury during neck lifts is relatively low, with studies reporting a temporary injury rate of 1 %−2 %.⁷⁵ The cervical branch of the facial nerve is the most vulnerable, with an injury rate of 1.7 %, which typically induces transient weakness that resolves within a few months.⁷⁶ Permanent nerve damage is extremely rare, and occurs in <0.03 % of cases.⁷⁵

Psychological impact

Facial nerve injury is associated with significant psychosocial burden, with up to one-third of patients experiencing anxiety or depression.^77,78 Quality of life, social functioning, and appearance-related distress correlate more with illness perception and mental health than with clinician-graded severity, often leading to social withdrawal due to communication challenges.79, 80, 81 These findings highlight the need for routine psychological screening and support within multidisciplinary facial nerve clinics. Surgical and rehabilitative interventions can improve outcomes but should be paired with counseling that manages expectations using validated patient-reported measures and minimal important change thresholds.82, 83, 84

Emerging technologies for facial nerve preservation

Emerging technologies are increasingly being explored to enhance facial nerve preservation in aesthetic surgery. Intraoperative nerve monitoring, widely used in salivary gland surgery, reduces deficits and operative time and may be adapted for cosmetic procedures.⁸⁵ Imaging-based techniques, such as systemic bevonescein, have shown safety and improved nerve visualization in early trials.⁸⁶ Robotic systems with real-time nerve monitoring, demonstrated in a sheep model, successfully aborted drilling within 0.1 mm of the facial nerve without injury.⁸⁷ These innovations suggest a future role for monitoring, imaging, and robotics in improving safety and outcomes in aesthetic surgery.

Conclusion

This review highlights the anatomical complexity and clinical relevance of facial nerve preservation in cosmetic surgery. Though permanent injury is rare, the nerve’s sensorimotor importance necessitates precise technique and detailed anatomical knowledge. Emphasizing surgical precision and landmark-based dissection can reduce nerve injury and optimize both functional and aesthetic outcomes.

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Patient consent statement

Not applicable, as this manuscript does not involve identifiable patient data or case reports requiring individual consent.

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Clinical trial registration information

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Funding

This study was funded by the William Harmon for Surgical Education and Research Fund.

Declaration of competing interest

None.

Data availability

All data generated or analyzed during this research are included in this published article. No supplementary files were created, as all relevant data are comprehensively presented in the main manuscript.