Brow Ptosis

Etiology

Brow ptosis is almost always acquired. Congenital brow ptosis is rare and occurs when the facial nerve and/or the frontalis muscle are underdeveloped.

Cases of acquired brow ptosis may arise in a variety of ways:

• Age-related: This is the most common form and is associated with changes in the periorbital tissues. Increased laxity of the connective tissue, skin, and frontalis muscle initially leads to drooping in the lateral third of the eyebrow; this may progress to ptosis of the medial two-thirds if left untreated (see Image. The Frontalis Muscle).[3]
• Traumatic: Damage to the intracranial, intratemporal, or extratemporal facial nerve can cause brow ptosis. A hemifacial palsy will result if the damage occurs anywhere between the facial nerve nucleus proximally and the pes anserinus distally. Damage limited to the frontal branch will denervate the ipsilateral frontalis muscle and parts of the corrugator supercilii, procerus, and orbicularis oculi muscles.[4] Fracture of the temporal bone is one of the most common causes of traumatic facial palsy. Other causes include trauma to the parotid gland, zygomatic arch, and mandibular body.
• Myogenic: Myopathy specific to the facial musculature and systemic myopathy can contribute to brow ptosis via atrophy or denervation of the frontalis muscle. These conditions include myasthenia gravis, myotonic dystrophy, and oculopharyngeal muscular dystrophy.[5]
• Infectious: Ramsay Hunt syndrome is a reactivation of the varicella-zoster virus that leads to facial paralysis and a herpetic rash of the ear canal, auricle, scalp, or oropharyngeal mucous membranes. This condition causes an ipsilateral facial palsy that includes brow ptosis.[6] Many other infectious agents can lead to central or peripheral facial nerve dysfunction, including but not limited to: herpes simplex virus, Borrelia burgdorferi (Lyme disease), Treponema pallidum (syphilis), West Nile virus, human immunodeficiency virus, SARS-CoV-2, and poliovirus.[7][8]
• Spastic: Congenital or acquired spasms of the orbicularis oculi can pull the brow down and away from its anatomic position, eventually causing a permanent change. Examples include blepharospasm and hemifacial spasm.[9]
• Neoplastic: Neoplasms of or infiltrating the facial nerve may affect its function and cause brow ptosis. Some of the most common include cancer of the overlying skin, like melanoma and squamous cell carcinoma, or more proximal masses, like acoustic neuromas.
• Iatrogenic: Operations in the area of the temple and lateral forehead pose a significant risk to the innervation and structural integrity of the brow. Overall, the procedures that pose the highest risk for postoperative facial nerve palsy are temporal artery biopsy, acoustic neuroma resection, and temporomandibular joint procedures. Operations to improve brow and overall facial cosmesis, such as endoscopic and open facelift procedures, can cause facial nerve palsy and exacerbate the problem they were intended to correct, but this occurs in less than 1% of procedures. Botulinum toxin injection also risks brow ptosis; overzealous or misplaced injections effectively denervate the brow elevators.[10]

Epidemiology

Anecdotally, it would appear that most cases are associated with the natural aging process, although literature definitively investigating the epidemiology of brow ptosis is lacking. Congenital brow ptosis is rare, as only 4.9% of facial palsy cases are present at birth.[7] The small proportion of remaining cases is attributable to the other acquired etiologies discussed above.

Pathophysiology

Several soft tissue layers comprise the brow. From superficial to deep, they are the skin, the subcutaneous fat, and the frontalis muscle; deep to this, there are the periosteum and skull—the frontal bone centrally and medially, and the zygomatic bone laterally.[11] The frontalis muscle is the sole elevator of the brow.[12] The depressors of the eyebrow include the orbicularis oculi, procerus, and depressor supercilii muscles (with some anatomists considering the latter to be simply a portion of the orbicularis oculi muscle).[13] The facial nerve innervates all muscles of facial expression; its frontal branch innervates the frontalis and the lateral portions of the orbicularis oculi and corrugator supercilii, while the zygomatic branch innervates the procerus, the medial aspects of the corrugator supercilii and orbicularis oculi, and the depressor supercilii (see Image. Motor and Sensory Supply, Face and Superficial Nerves of the Head and Neck).[14]

Excessive sun exposure, gravity, and the natural involutional degeneration of the skin and underlying tissues are the main contributors to brow ptosis. Denervation of the brow elevators, whether via trauma, surgery, botulinum toxin treatment, or a disease process, will also lead to brow ptosis. Long-term spasm of the brow depressors can cause brow ptosis as well; spasms may result from spastic dystonia after facial denervation, facial tics in conditions like Tourette syndrome, or spastic syndromes like blepharospasm and hemifacial spasm due to irritation of the intracranial facial nerve by the pulsations of a nearby artery (see Image. Typical Blepharospasm).

History and Physical

The historical evaluation of an individual with brow ptosis is key to determining the underlying etiology.

• The history of the present illness should focus on the onset and progression of symptoms. Insidious development of brow ptosis in an older patient may indicate an age-related cause. In contrast, patients with a more rapid onset may be experiencing Bell palsy, trauma, neoplasm, or other more unusual pathologies. A waxing and waning course with accompanying fatigability could represent myotonic dystrophy, myasthenia gravis, or oculopharyngeal dystrophy.
• The medical history should specifically evaluate for past instances of facial paralysis of any etiology, even cases long in the past, as well as any injuries in the upper third of the face or the temporal region.
• A history of chemotherapy and/or radiation therapy should be elucidated, as these exposures can speed cutaneous and soft tissue aging.
• The surgical history should reveal all procedures performed in the area of the brow and along the course of the facial nerve, including any neuro-otologic or neurosurgical procedures. Patients should also be asked if they have received chemodenervation with botulinum toxin injections.
• The social history should reveal sun exposure, smoking, and drug use, as they can all expedite involutional changes.

The physical examination should follow a systematic, stepwise approach generalizable to all periorbital aging.

• Neutral brow position should be evaluated by having the patient close their eyes, relax the facial muscles, and open the eyes as gently as possible without raising the brows. This maneuver is challenging for many patients and may require several attempts.
• Brow versus eyelid pathology should be differentiated by manually elevating the brow to the neutral position. A lid still ptotic after brow elevation indicates true blepharoptosis rather than pseudoptosis caused by a drooping brow and excess skin.
• Blepharoptosis should be thoroughly evaluated. The margin-reflex distance (MRD) is recorded. This is the distance measured from the corneal light reflex to the upper lid margin (MRD-1) or lower lid margin (MRD-2). An MRD-1 of less than 2 to 3 mm is indicative of blepharoptosis. The distance must also be measured between the upper eyelid margin and the superior palpebral crease. More than 8 to 10 mm often indicates blepharoptosis due to levator aponeurosis dehiscence. Any brow position or shape asymmetry should also be noted, even if only due to personal grooming. An asymmetric brow with symmetric eyelids may mask blepharoptosis on the side of the elevated brow due to frontalis contraction compensating for a ptotic eyelid. The ice pack test may be employed at the bedside if myasthenia gravis is suspected: placing an ice pack on the patient's eyelids (with a barrier to prevent frostbite) for 2 to 5 minutes will often improve blepharoptosis in patients with myasthenia gravis.[15] Finally, the patient should be evaluated for the Hering phenomenon. Suppose the elevation of a ptotic eyelid, or the eyelid on the side of the elevated brow, produces drooping of the contralateral upper eyelid. In that case, the patient may have bilateral but asymmetric blepharoptosis. Brow height asymmetry is also commonly caused by hemifacial microsomia, which is more frequently present on the right side than on the left.[16] The presence of hemifacial microsomia is definitively confirmed with computed tomography; however, placing a wooden tongue depressor transversely across the patient's bite, posterior to the incisors, when the patient's head is in a neutral position, will demonstrate an asymmetry of lower facial height if the tongue depressor sits at an angle rather than parallel to the floor.
• To complete a thorough periorbital examination, festoons and fat pseudoherniation should be evaluated with digital pressure on the globe while examining the upper and lower eyelids. The former will not enlarge, but the latter will. Festoons will also contract with effortful eye closure and often extend inferior to the inferior orbital rim, while pseudoherniated fat is contained at the rim by the arcus marginalis. Lower eyelid laxity should be evaluated via the snap test. This is performed by distracting the lid from the globe, then releasing and observing lid recoil, which should take no longer than 2 seconds and occur without the patient needing to blink. The lower eyelid vector should be evaluated by observing the relationship between the cornea and the cheek with the patient's head in the Frankfort horizontal position (a line between the top of the external auditory meatus and the inferior orbital rim is oriented parallel to the floor). The vector is negative if the cornea is anterior to the cheek skin at the infraorbital rim. This is associated with aging and an increased risk of ectropion if lower eyelid blepharoplasty is performed without supporting the lower eyelid concomitantly. Finally, tear production should be evaluated via the Schirmer test. Filter paper is inserted into the fornix of the lower eyelid; if there is less than 10 mm of dampness after 5 minutes, tear production is not adequate, and the surgeon must adjust the operative plan accordingly.
• If brow lifting is to be undertaken, the hairline position and shape of the forehead must be visually evaluated to inform the surgeon's choice of operative approach.
• A thorough cranial nerve exam should be performed, especially if damage to the facial nerve is suspected.[11]

Evaluation

Evaluation of brow ptosis outside of a thorough history and physical examination is rarely necessary. However, there are some cases in which imaging and laboratory studies are beneficial or even diagnostic. Myogenic causes of brow ptosis may be elucidated with certain assays; for example, myasthenia gravis may be diagnosed via serologic testing for acetylcholine receptor antibodies.[17] Brow ptosis caused by a neoplasm will necessitate a thorough evaluation of the mass. These assessments vary widely based on the suspected type of neoplasm, including anything from a shave biopsy to magnetic resonance or positron emission tomography scanning. However, if the decision is made to proceed with brow lifting, preoperative facial photographs should be taken and then posted intraoperatively for reference during surgery. The views should include frontal in repose and with raised eyebrows, as well as bilateral profile views in the Frankfort horizontal position with and without eyebrow raising. Not only does eyebrow raising help assess the function of the frontal branch of the facial nerve and the frontalis muscle, but it may also elucidate the presence of blepharoptosis and pseudoherniation of fat within the lower eyelids.

If the patient wishes to undergo brow lifting, the evaluation should also include attention to the patient's forehead anatomy, specifically the height of the forehead and its degree of convexity. The position of the hairline should be noted, as should the degree of brow ptosis, the heaviness of the brow soft tissues, and whether or not additional surgery will be performed concurrently with the brow lift. Critically, the amount of hair on the scalp should be assessed, as well as any personal or family history of hair loss. These details are fundamental for devising an appropriate surgical plan. For example, patients with low hairlines who would benefit from hairline elevation may be good candidates for coronal brow lifting.

On the other hand, if the hairline needs to be lowered, a pretrichial incision would be more appropriate so that forehead skin may be excised and the scalp advanced. If reduction of the bony brow is necessary for gender affirmation, either a coronal or a pretrichial/trichophytic approach will provide the correct exposure; these approaches are also among the most effective in terms of the degree of brow elevation achievable, although suture suspension is the most powerful in that regard. Tall foreheads with prominent convexities are more challenging to address with an endoscopic technique due to the instruments' limited length and visibility around the frontal bone's curvature. The endoscopic left may also elevate the hairline, albeit subtly. Patients in whom hair loss is anticipated may be poor candidates for coronal or pretrichial brow lifting, because of visible scarring, unless a head covering or hairpiece is to be worn routinely. 

While blepharoplasty may be performed with any surgical brow lift, it is all but mandatory for the transblepharoplasty technique. If midface lifting is desired, it can be accomplished separately from the browlift or as an extension of an endobrow operation. Glabellar rhytids can be reduced through division of the corrugator supercilii muscle using coronal, pretrichial, trichophytic, or endoscopic approaches. Other considerations include the need to correct brow position asymmetry (best achieved with direct, transblepharoplasty, or suture suspension techniques), perform the procedure under local anesthesia (again, direct, transblepharoplasty, or suture suspension), or even avoid surgical intervention altogether (thread lifting or botulinum toxin). For a summary of these considerations and a decision-making aid, please see the Image. Brow Lifting Techniques, Table.

Treatment / Management

Selection of the most appropriate treatment for a given individual with brow ptosis depends on forehead and brow anatomy, ptosis etiology, severity, and, most importantly, patient goals.[18] For age-related brow ptosis, surgical management is most effective. Surgery may also be indicated for some traumatic, neoplastic, and iatrogenic causes. Those surgeries may include nerve decompression, removal of a neoplasm, or nerve reconstruction with or without additional brow lifting. The most common procedures used to treat brow ptosis are discussed below. Many of these procedures may be combined with other rejuvenation procedures, such as upper blepharoplasty, botulinum toxin injection, or skin resurfacing, to optimize patient outcomes and provide a more holistic approach to facial rejuvenation.(B3)

An in-depth understanding of forehead and periorbital anatomy is fundamental to successfully using the following techniques. Medially, the soft tissue of the brow is composed of the skin, subcutaneous fat, galea aponeurotica, loose areolar tissue, and pericranium. Laterally, the conjoint tendon divides the forehead and temporal regions, a confluence of the galea aponeurotica, temporoparietal fascia (TPF), pericranium, and temporalis muscle fascia. The conjoint tendon must be released to allow the forehead to elevate during any type of subperiosteal brow lifting. Lateral to the conjoint tendon, the soft tissue layers include the skin, subcutaneous fat, TPF, superficial layer of the deep temporal fascia, temporal fat pad, temporalis muscle, and pericranium (see Image. Fascial Planes of the Face).

The frontal branch of the facial nerve runs just deep to the TPF along a course approximated by the Pitanguy line. This line runs 0.5 cm below the tragus and 1.5 cm above the lateral extent of the brow (see Image. Pitanguy Line), crossing over the central portion of the zygomatic arch.[19] There may be more than one frontal branch, however, and arborization of the nerve occurs distally, so the Pitanguy line should be considered an indicator of a danger zone, rather than a roadmap to the location of the facial nerve. The supraorbital neurovascular bundle exits the orbit at the midpupillary line and courses superiorly to supply sensation and blood to the lateral brow. The bundle passes through a notch roughly two-thirds of the time and a foramen the other one-third, although the left and right sides may be asymmetric.[20] 

Whether there is a notch or a foramen can be an important consideration, particularly during coronal brow lifting, as a foramen may limit the neurovascular bundle's mobility and thereby cause traction or avulsion injuries. The supratrochlear bundle is medial to the supraorbital bundle and supplies sensation and blood to the glabella and medial forehead. Both bundles travel in a plane deep to the frontalis muscle but give off perforating vessels to the overlying skin. Around the periphery of the orbit lies the arcus marginalis, another condensation of connective tissues that brings together the periorbita, the pericranium, and the orbital septum. This too must be divided superiorly and laterally to provide mobility during subperiosteal lifting procedures.

Endoscopic Brow Lift

Described by Isse in 1994, the endoscopic brow lift—or "endobrow" procedure—is one of the most commonly employed approaches to brow lifting (see Image. Endoscopic Brow Lifting, Video).[21] The operation is performed via 5 incisions placed 1 to 2 cm behind the hairline: 1 median and 2 paramedian incisions, each 1 to 2 cm long, and 2 temporal incisions perpendicular to a line drawn from the nasal ala through the lateral canthus. The paramedian incisions are marked directly above the planned peak of the brow. They must be long enough to accommodate whatever apparatus will fixate the forehead in its elevated position (see Image. Endoscopic Brow Lift Incisions). The temporal incisions are used for lateral access to the brow and orbit, but may be converted to fusiform skin excisions if additional temporal lifting is needed. The procedure begins with the development and elevation of a subperiosteal plane down to the level of the supraorbital rims, which can be done under endoscopic visualization or blindly.(B3)

If performed without visualization for rapidity, many surgeons will introduce the endoscope for the last centimeter or so of elevation to ensure the integrity of the supraorbital neurovascular bundles. Posterior subperiosteal elevation is also performed to permit the scalp to move backwards slightly due to the elevated forehead. Laterally, a plane is developed deep to the TPF, on top of the temporalis fascia, and this is followed to the lateral aspect of the orbital rim, taking care to avoid avulsing the medial zygomaticotemporal "sentinel" vein, which lies within 1 cm of the frontal branch of the facial nerve.[22] The periosteum should then be elevated around the orbital rim down to the level of the lateral canthus. However, elevation may continue onto the zygomatic bone if a midface lift is planned. The conjoint tendon must then be released to make the forehead and temporal compartments contiguous, permitting effective brow elevation; dividing the tendon is easiest if approached laterally.

The arcus marginalis is then divided from lateral canthus to lateral canthus to mobilize the brow soft tissues, and the corrugator supercilli muscles may be divided if a reduction in glabellar frown lines is desired, taking care to avoid overly aggressive resection, which may lateralize the medial brows and make them appear unnatural. The forehead is then elevated to the desired position and fixated with one of many methods.[21][23] Resorbable polymer implants may be drilled into the frontal bone to hook the forehead periosteum, suspending it. Alternatively, a "bone bridge" may be drilled into the calvarium, permitting anchorage of a suture that is passed through the periosteum of the forehead. Multiple other techniques have been described as well.[24] If temporal lifting via the lateral incisions is desired, the TPF at the anterior edge of the excision is anchored posterosuperiorly to the temporalis fascia.(B3)

The endoscopic brow lift is best suited for patients with low or average brow height, defined as 6 cm or less from the brow to the hairline, and those without significant forehead curvature or bossing of the brow ridges. Some disadvantages of this technique include the risk of damage to the frontal branch of the facial nerve (which would exacerbate brow ptosis), risk of damage to the supratrochlear and supraorbital nerves (which would cause forehead numbness), difficulty in correcting brow asymmetry (because the forehead is elevated as a unit), and limited ability to achieve a dramatic elevation with this minimally invasive approach (2-4 mm).[25] The most significant limitation on the degree of lift achieved with the endobrow procedure is downward traction from the closure of concomitantly performed upper eyelid blepharoplasty, and the most common complication of this technique is forehead itching.[25]

Gliding Brow Lift

A less technically demanding variant of the endobrow lift is the "gliding brow lift," described by Viterbo and colleagues in 2019.[26] This procedure differs from the traditional endoscopic approach in that the elevation is done blindly in a subcutaneous plane rather than a subperiosteal one. However, similar paramedian incisions are used behind the hairline. The risk of nerve damage is virtually eliminated by dissecting in a subcutaneous plane rather than a subperiosteal one. Still, because skin is very elastic, it must be stabilized effectively during the healing process for the lift to persist. To do so, a "hemostatic net" of 4-0 and 5-0 nylon sutures is placed, taking numerous, regularly spaced bites across the forehead to tack the skin to the underlying muscle. While the sutures appear somewhat alarming immediately after surgery, they reduce the risk of hematoma formation despite the relatively vascular plane of elevation, and they are removed on postoperative day 2. The effect and longevity of this technique are reportedly comparable to those of endoscopic lifting.

Coronal Brow Lift

Open coronal approaches constitute a more traditional category of brow-lifting options. Pretrichial incisions are placed at or just in front of the hairline, while trichophytic incisions are hidden just posterior to the hairline; the classic coronal incision passes directly over the vertex of the scalp and may take a zig-zag or undulating shape for the sake of scar camouflage.[27] Dissection is carried forward from the central part of the incision in the subgaleal plane until diving subperiosteally 1 to 2 cm superior to the orbital rim, unless a pericranial osteoplastic flap or a frontal cranioplasty for gender affirmation is planned, in which case, the dissection may be entirely subperiosteal (see Image. Pretrichial Variant of the Coronal Brow Lift). As with the endoscopic lift, the temporal portions of the elevation occur atop the temporalis fascia to protect facial nerve branches, and the conjoint tendons are also released.

If desired, the corrugator supercilii muscles may be divided to smooth the glabella. Division of the arcus marginalis is also essential in open approaches, and avoiding injury to the supraorbital neurovascular bundles is critical. When the bundles pass through foramina, they may obstruct access to the orbital rim and require osteotomies of the inferior rims of the foramina for complete forehead flap mobilization; performing these osteotomies to convert foramina into notches may place the supraorbital nerves at increased risk of injury if not done carefully. After flap elevation, the excess skin and soft tissue are excised as necessary, and the incision is closed in layers. Coronal brow lifts allow for more dramatic brow elevation than the endoscopic option provides, and they do not require expensive endoscopic equipment; however, they result in significant scars that may be revealed by hair loss and are more likely to cause minor complications like forehead numbness, pruritus, and alopecia, as well as long-term anesthesia or hypesthesia posterior to the incision in nearly all patients.[28] 

The pretrichial coronal approach is also commonly used for facial feminization procedures, in which the brow lifting operation is accompanied by adjustment of the frontal hairline and reduction of the supraorbital ridge.[29] If concomitant hairline advancement is desired, subcutaneous elevation posterior to the incision will afford 2 to 4 cm of movement. Still, care should be taken during wound closure to avoid tension, widening the scars, and making them more visible just anterior to the new hairline. Pretrichial or trichophytic incisions may be used for cisgender patients as well; they may make the scar more visible along the anterior hairline, but they will avoid the posterior displacement of the hairline seen with a coronal incision. Importantly, it is critical to counsel patients that while forehead numbness after surgery is most likely due to temporary supraorbital or supratrochlear nerve dysfunction, there will always be some degree of hypesthesia or paresthesia that persists posterior to the incision due to transection of distal sensory nerve branches.

Direct Brow Lift

A far less invasive option than coronal approaches, the direct brow lift is performed through a fusiform excision just above the hair-bearing brows. Excess skin and soft tissue are removed to create a considerable lift with a relatively minor procedure that can easily be performed in the clinic under local anesthesia. This procedure is the most effective option for heavy lateral hooding and is the most straightforward procedure for correcting brow asymmetry.[30] Some drawbacks include the risk of visible scarring—particularly over the medial brow, where the skin is more sebaceous—and an increased chance of excessive elevation that may result in a surprised look. Still, because this technique addresses each brow separately, it is ideally suited for alleviating most cases of brow asymmetry.[31] If additional lift is desired, a 3-0 polydioxanone suture can be used to suspend the dermis of the brow to the periosteum. Still, avoiding injuring or encircling the supraorbital nerve with this suture is important, as it may cause numbness or neuropathic pain.

A “deep plane” variant involves incising orbicularis oculi and suspending the muscle and its underlying fat to improve longevity. Still, this technique should only be employed lateral to the supraorbital nerve, thus making it primarily useful for female brows.[30] The technique of a simple direct brow lift is very straightforward, in that it amounts to nothing more than a skin excision; however, determining where and how much skin to remove is key. A simple way to do this is to have the patient sit upright or stand, and then manually lift the eyebrow to its desired position, holding a marking pen at the level of the top of the brow peak, but not touching the skin. Upon releasing the brow, a dot is placed on the skin where the brow sat when elevated. The same procedure is repeated at a few different locations along the superior margin of the eyebrow, which will delineate the superior extent of the excision. The inferior extent will follow the upper margin of the eyebrow (see Images. Direct Brow Lift Marking and Direct Brow Lift.).

Mid-Forehead Brow Lift

The mid-forehead lift is similar to the direct brow lift, which places the skin excision in a transverse forehead rhytid rather than immediately above the eyebrow; this is primarily a procedure of historical interest due to the often readily apparent scarring it produces.[32] With this procedure, a single, long skin excision can be used to lift both brows together, or individual excisions can be employed on each side, symmetrically or asymmetrically, sharing a rhytid or located at different levels. The higher the excisions are placed, the less effective the lift will be, because the greater the expanse of skin between the lifting point and the brows themselves, the more the skin can stretch and allow the brow to descend.

Suture Suspension Brow Lift

For severe brow asymmetry, unilateral suture suspension of the ptotic brow to a titanium miniplate fixated to the frontal bone at the level of the hairline may be effective. As a side benefit, the sutures can be tightened under local anesthesia if the brow ptosis recurs or worsens. Tessa Hadlock developed the percutaneous suture suspension brow lift at the Massachusetts Eye & Ear Infirmary for use with facial paralysis patients, particularly those who wanted to avoid a direct brow lift scar or for whom a direct brow lift would not provide adequate elevation or longevity (see Image. Right Brow Ptosis With Facial Paralysis). A short, pretrichial incision will later accommodate a 5-hole titanium miniplate, and 3 stab incisions above the brow follow that. A 2-0 silk suture is then threaded through the stab incisions with a reusable Keith needle to create two slings, which are in turn anchored to the miniplate (see Image. Suture Suspension Brow Lifting). The key is to pass the suture through the superficial dermis above the brow to maximize the mechanical advantage, then drive the suture down to the periosteum to meet the miniplate. The procedure can provide a nearly unlimited elevation; however, as with any brow lift, the elevation will decrease over time.

Transblepharoplasty Brow Pexy (Internal Brow Lift)

The transblepharoplasty browpexy is a way to combine the treatment of upper lid dermatochalasis or blepharoptosis with the treatment of brow ptosis.[33] These conditions are often comorbid, which makes this approach an efficient one. However, it is best used for the female brow because the suspension point must be lateral to avoid injury to the supraorbital neurovascular bundle. An upper eyelid blepharoplasty is performed first; then, dissection is carried superiorly along the orbital septum until the supraorbital rim is reached. At this point, either the pericranium can be elevated with the brow if a bioresorbable suspension device is drilled into the bone (similar to an endoscopic brow lift), or the periosteum can be left in place and used to anchor a suture that suspends the brow (similar to a direct brow lift). If a suspension suture is used, it is more challenging to get symmetric results, due to the limited access afforded by the blepharoplasty incision, and the brow tends to take on a feminine peak (see Image. Transblepharoplasty Brow Pexy). The lift is slightly broader and easier to reproduce symmetrically if a suspension implant is placed. In this case, the conjoint tendon's inferior portion must be released to facilitate an effective lift, and the arcus marginalis should be disrupted to mobilize the periosteum. Similar to the results of the endoscopic approach, the lift obtained with this procedure is limited because it is performed with upper eyelid blepharoplasty.

Thread Lifting

Barbed resorbable threads are becoming a popular option for treating the aging face at multiple levels, and even for contouring of the arms and belly. For brow lifting, a blunt cannula is used to place bidirectionally barbed 4-0 sutures ("threads") via stab incisions made with an 18-gauge needle. The sutures themselves have barbs oriented away from a central point on the thread, which allows them to pull up on the brow and anchor into the subdermis simultaneously. Multiple threads are typically deployed along several vectors to achieve the desired effect. Once the sutures are in place, the brow is manually manipulated into the desired position while tension is kept on the thread, thus permitting the barbs to engage. The threads can be tied off and then cut, or just cut and left below the skin surface. When the sutures are made of polydioxanone, the lift should last at least 6 months, but the duration is 2 to 3 times as long if poly-L-lactic acid threads are used.[34][35] The most likely complications of this technique are asymmetry and dimpling or rippling of the skin due to the thread not being situated at an even depth within the subdermis. Usually, these irregularities settle with gentle massage and time.(B3)

Selective Chemodenervation

Lastly, botulinum toxin injections can be used to treat spastic brow ptosis or even slightly elevate the brow by decreasing the resting tone of the depressor supercilii muscle and thereby augmenting the opposing action of the frontalis muscle. A small injection of 1 to 2 units placed just under the skin, inferior to the eyebrow at the lateral canthus level, can help elevate the brow's tail (see Image. Chemical Brow Lift With Botulinum Toxin). This technique is typically reserved for the female brow because injecting more medially risks causing blepharoptosis by weakening the levator palpebrae superioris muscle. If blepharoptosis does result, apraclonidine eyedrops will help to alleviate symptoms. The injections should last 3 to 4 months.

Differential Diagnosis

Brow ptosis is a fairly straightforward and well-defined diagnosis, but it may be confused with or obscured by other periorbital pathologies. Asymmetric brow ptosis may seem like unilateral pathology unless a thorough physical examination reveals that the more ptotic side was masking the appearance of the less ptotic side. Severe dermatochalasis or blepharoptosis may distract the physician from identifying concomitant brow ptosis. A thorough history and physical examination will reveal whether a patient’s brow ptosis is age-related, traumatic, myogenic, spasm-induced, infectious, neoplastic, or iatrogenic.

Prognosis

The prognosis for brow ptosis highly depends on the etiology and the patient's primary concerns. Full resolution and patient satisfaction can usually be achieved for those mainly focused on the visual field deficits caused by their ptotic brows.[36] That said, patients must be counseled that effective rejuvenation does not mean a permanent cessation of facial aging, but rather an offset by 5 to 10 years, so that while they may look persistently younger than expected based on biological age, the brows will descend over time nonetheless. Patients whose concerns are primarily cosmetic have higher dissatisfaction rates than those with predominantly functional complaints. Patients with non–age-related etiologies have more varied prognoses.

Complications

Complications of brow lifting include numbness of the forehead due to supratrochlear or supraorbital nerve damage (5.5%), alopecia (2.8%), temporary or permanent brow asymmetry due to asymmetric elevation or motor nerve injury (1.7%), and patient dissatisfaction (7.4%). Dissatisfaction may stem from many issues, including persistent discomfort from implanted suspension devices, insufficient brow elevation, excessive brow elevation, division of the corrugator muscles that leads to a "surprised" appearance, and unsightly scarring. Nonsurgical brow rejuvenation complications are infrequent. The most common complication of botulinum toxin treatment is periorbital bruising in 1.7% of patients or transient blepharoptosis.[10]