6Skin resurfacing with Microbotox and the treatment of keloids

INTRODUCTION

Microbotox is a useful and versatile chemoresurfacing technique (1) using onabotulinumtoxinA that can improve the sheen and texture of skin, decrease sweat, oil and sebum production, improve acne, reduce the appearance of open pores, decrease fine lines without altering deep muscle movement, lift and sculpt the jawline, improve scars, smoothen the neck and undereye areas, and generally give a natural appearance to the face without an “overbotoxed” look. It can also be used to improve the appearance of scars and to treat established keloids when used in conjunction with intralesional triamcinolone and intense pulsed light (triple therapy).

It involves multiple injections of small boluses of diluted onabotulinumtoxinA into the dermis or the interface between dermis and the superficial layer of facial or neck muscles over the affected area. There are a variety of refinements that can be achieved as the onabotulinumtoxinA exerts its effect on both muscle movement and on the skin itself.

In the muscle, the Microbotox is injected superficially so as to weaken the superficial layer of muscle fibers without compromising deep muscular activity. This decreases fine lines and wrinkles in difficult to treat areas such as the lateral forehead, the undereye area and the neck and jawline. In the skin, the effect of the onabotulinumtoxinA is to decrease the production of sweat (which is well documented), sebaceous secretions, and bring about a shrinkage of the sweat and sebaceous glands, which in turn causes a “tightening” of the skin envelope. Pores appear reduced in size and the skin becomes smooth and unlined. Acne is visibly improved.

The technique can be applied to the forehead, T-zone, cheeks, lower eyelids, jawline, neck, décolletage, and buttocks.

HISTORY

When we started using onabotulinumtoxinA in the 1990s for intramuscular injection of forehead rhytides, one of the common observations was that the overlying forehead skin would often become shiny, smooth, and tight with hardly a pore in sight. Many patients liked this “resurfaced” look. This effect was the result of onabotulinumtoxinA intended originally for the frontalis muscles diffusing back into the skin and affecting the sweat and sebaceous glands. It was usually seen when large boluses of onabotulinumtoxinA were administered to the forehead, allowing this diffusion to occur.

At the same time, there were many patients who also complained that the forehead felt too frozen and stiff and some had difficulty lifting their brows or even complained of droopy eyebrows and loss of definition of the eyelid crease. Our early experience saw us injecting too much onabotulinumtoxinA into the forehead in the mistaken belief that a smooth forehead was the only desired ideal of patients. What patients actually want is a smooth forehead but one that is still able to move naturally and elevate. This seems a paradox since the muscles that create the forehead lines are the same muscles that are responsible for elevation. It therefore seemed obvious that we had to devise a technique of onabotulinumtoxinA administration that decreased visible forehead lines but yet still allowed the underlying muscles to move and the eyebrows to elevate.

Another clinical problem encountered was in achieving a smooth lower eyelid. After the traditionally placed onabotulinumtoxinA injections for the glabella, crow’s feet, and forehead regions, patients often experience enhanced “bunny lines” and wrinkles just under the lower lid eyelash margin. Some would complain that these“new”wrinkles were disturbing. Traditional onabotulinumtoxinA can be administered to the infraorbital

area and to the hypertrophic muscle bundle of the lower lid. In some patients, the result can be pleasing with a slight opening of the orbital aperture, which makes the eye look bigger and more attractive. These are usually younger patients without significant lower eye bags. But in others, there can be distressing complications with resulting “bags” under the eyes, a waterlogged appearance and an unwelcome inanimate response of the lower lid to smiling. Patients feel they look worse than before the onabotulinumtoxinA administration. These are invariably older patients who may have unrecognized eye bags or skin laxity in whom relaxation of the infraorbital orbicularis oculi muscle actually allows the eye bags to bulge and become more visible. The action of the muscles prior to onabotulinumtoxinA administration helps to keep the skin tightened in a state of tension and push the eye bags inward, thus disguising them. This is unmasked once the muscles relax and are no longer able to provide any resistance to the eye bags as they herniate outward.

A third problem area was the neck. Early techniques advocated administering traditional onabotulinumtoxinA (i.e., onabotulinumtoxinA diluted with 2–2.5 ml of saline) into the anterior and lateral platysmal bands without injecting into the muscle in between these bands, over the horizontal neck creases or above the jawline. Some patients had good results with softening of the platysmal bands and improvement of the cervicomental angle but none experienced a lifting of the jawline nor improvement of neck skin quality nor horizontal lines.

In looking for a solution to these three problems, the author drew on his experience with intradermal injections of onabotulinumtoxinA to the axilla to decrease hyperhydrosis (2–4) and odor and developed the Microbotox technique.

MICROBOTOX (MESOBOTOX)

Microbotox is essentially an intradermal or subdermal injection of very dilute onabotulinumtoxinA to affect the sebaceous and sweat glands as well as the superficial layer of facial muscles. It requires careful preparation of the solution and a sensitive and refined injection technique, which is the key to a successful outcome. Injecting too large a bolus at any given point will flood the area with onabotulinumtoxinA and cause deep muscular paralysis, which may be undesired.

Although having performed this technique for over a year, in 2001 the author coined the term Mesobotox as the depth of injections in this technique correlated with the depth of injections used in traditional mesotherapy. Shortly after that however, the author felt that the dosage of onabotulinumtoxinA being significantly reduced and its application over a wide area of skin via multiple injections of small boluses made the term Microbotox more appropriate instead. The author has lectured extensively on this topic since then (5).

Physiologic Basis for Action

OnabotulinumtoxinA is a very versatile drug that inhibits a variety of receptors including substance-p. In treating rhytides by blocking neuromuscular transmission, onabotulinumtoxinA works on cholinergic receptors. Sweating is also largely mediated through cholinergic receptors and is inhibited by onabotulinumtoxinA as well. However, onabotulinumtoxinA also has the ability to work on noradrenergic receptors, which partly mediate sweat and sebaceous secretions as well. Hence onabotulinumtoxinA is able to decrease muscular activity as well as bring about a change in quality of the overlying skin of the injected area through this double mode of action.

Mechanism of Action

In traditional onabotulinumtoxinA administration, the objective is to bring about muscle weakening or paralysis and in the case of onabotulinumtoxinA facial sculpting (6), an atrophy of the masseteric muscle bulk. Therefore, the onabotulinumtoxinA should be injected into the muscle itself for best effect (Fig. 6.1A–E). This can sometimes lead to pain and bruising. Because the margin for error is higher when injecting into the muscle, we have tended to be more cavalier in the way we inject

into these traditional areas, often not ensuring that we are delivering the correct dose of onabotulinumtoxinA in a precise fashion.

For Microbotox, the delivery technique is very important as we are injecting multiple tiny boluses of onabotulinumtoxinA into the dermis or into the junction between the dermis and the superficial layer of the muscles of the face or neck. This weakens the superficial layer of the facial muscles, which are attached to the undersurface of the facial skin and are responsible for the fine lines and wrinkles that patients dislike.

In the skin, the sweat and sebaceous gland activity is reduced (mediated through both cholinergic and noradrenergic receptors) and they become atrophic. This causes the skin envelope to shrink and patients feel tighter and lifted. Reduction of sebaceous secretion also helps in the control of acne but more importantly makes the “open” pores appear smaller and less in number. As a result, the skin looks more refined and has a smooth sheen to it (Fig. 6.2A–E).

Dilution and Injection Technique for Microbotox

The author always uses a 100-unit bottle of onabotulinumtoxinA (Allergan, Irvine) diluted with 2.5 ml of normal saline. This dilution is used for all injections of onabotulinumtoxinA to the face or masseter muscles [onabotulinumtoxinA facial sculpting or facial slimming (6)] or even to the axilla with 0.1ml containing 4 units of onabotulinumtoxinA and 0.05 ml containing 2 units of onabotulinumtoxinA.

0.1ml droplets

0.05ml droplets

Figure 6.3 Microdroplet training: practice is required to enable the injector to release tiny droplets of diluted onabotulinumtoxinA regularly and evenly. Standard injections of 0.1 and 0.05 droplets are seen at the top left hand side. In comparison, the cluster of droplets below are both a single 0.05 ml droplet divided into multiple microdroplets. The cluster of droplets on the right is very fine (0.05 ml divided into 43 microdroplets) and realistically not achievable. The cluster on the left (0.05 ml divided into 12 microdroplets) is more practical.

A 0.1 ml droplet is quite large and it is easy to see how an inaccurately placed droplet near the eyebrow (when treating for glabellar frown lines) can diffuse down to the levator muscles, thereby causing temporary ptosis of the upper eyelid.

A 0.05 ml droplet contains 2 units of onabotulinumtoxinA and is my usual volume of injectate when doing routine intramuscular injections. Where muscles are thicker or more dense, then 0.1 ml droplets are used.

For Microbotox, that same 0.05 ml droplet can be injected in multiple smaller droplets. Depending on the skill of the operator, 0.05 can be injected in 10 to 20 drops. In the clinical situation if the operator can inject 0.05 ml in 10 drops this is sufficient.

In different parts of the face, neck, and body, different dilutions of Microbotox are used especially when treating patient solely for pore closure or smoothening the skin and not wanting to affect the underlying muscle activity.

Injecting the small boluses of onabotulinumtoxinA should be done slowly and evenly, each injection spaced about 1cm apart in a grid-like fashion. Once the injections can be done steadily and the boluses made even smaller, the injection distance can be reduced to 0.5cm apart. All air bubbles must be carefully removed from the syringe prior to injection as this may compromise the injection accuracy.

Figure 6.4 Twenty-four units of Botulinum injected superficially into the entire forehead as multiple small drops. Each drop should raise a small whitish bleb. If not it is too deep.

The objective is to retain as much muscular function and hence eyebrow elevation as possible but at the same time to smoothen the skin, reduce pore size, improve the sheen, and reduce rhytides especially those over the lateral forehead, which are a reflection of overactive frontalis muscle activity. Twenty-four to twenty-eight units are sufficient for the entire forehead including eight points of injection over the glabellar and eyebrow regions to decrease corrugator activity. If traditional onabotulinumtoxinA has already been given to the glabellar, eyebrow, and central forehead regions to create a brow lift as described by this author, then 16 units is sufficient just for the lateral forehead alone. This usually lasts 4 months. On an average, the forehead will be covered with 40 to 50 injection points (Fig. 6.4). To anesthetize the forehead, a supraorbital nerve block with a small bolus of Lignocaine 1% without adrenaline administered to the supraorbital nerves will provide adequate numbness and comfort for the patient. Additionally, Elamax 5 % (LMX 5) can be used to supplement the areas not covered by the nerve blocks. Surprisingly, because the injection bolus is so small patients seldom complain of pain even if an anesthetic is not used. It is better to underinject the lateral forehead to avoid any lowering of the eyebrow or sensation of heaviness. Patients should have a smooth forehead but still be able to elevate their eyebrows and look natural (Fig. 6.5A,B).

For the Microbotox technique, depending on the region of the face or neck to be injected, the required number of units are drawn up into a 1 cc syringe and then topped up to 1 ml with normal saline.

For example, if the forehead requires 24 units of onabotulinumtoxinA, then 0.6 ml of the prepared onabotulinumtoxinA (2.5 ml dilution) is drawn into a 1 ml syringe and an additional 0.4 ml saline is drawn up to make 1 cc of injectable solution. That is 24 units of onabotulinumtoxinA in 1 ml of solution.

For the injection technique, some practice is required, which can be gained by filling a 1 cc syringe with normal saline, attaching a 30G needle and then injecting small droplets onto a table top to practice delivering big and small boluses consistently. With this simple exercise, most physicians are surprised to learn that they are overinjecting the onabotulinumtoxinA many a time and not delivering evenly sized boluses with each injection (Fig. 6.3).

Patients often request a smoothening of the bunny lines and the fine lines under the eyelids, especially after onabotulinumtoxinA administration to the crow’s feet, glabella, and forehead regions, which makes the wrinkles of the undereye and paranasal regions relatively more prominent and noticeable (Fig. 6.6). This part of the face is extremely delicate with a small margin for error. With too little onabotulinumtoxinA, the result is negligible. With too much administered, the entire lower lid can take on the complications already described above. The author usually uses 8 to 12 units for the infraorbital as well as nasal bunny line region. The results last approximately 3 to 4 months and the patients are warned that this area may wear out faster than other areas simply because there is less onabotulinumtoxinA spread out over a wide area. For patients who want a slight degree of movement over the lateral orbicularis (crow’s feet region), then 24 to 28 units can be used for this area and the infraorbital and bunny lines as well. Surprisingly, many patients who used to receive traditional onabotulinumtoxinA in

Figure 6.6 Microbotox of the infraorbital and bunny line regions. The droplets should be evenly spaced out to prevent overrelaxation of the orbicularis muscle.

these areas now request Microbotox instead as they feel they look more natural and have less stiffness (Fig. 6.7A,B).

An infraorbital nerve block with a small bolus of anesthetic is used (to avoid any dilution and diffusion errors) although most patients can tolerate the infraorbital injections without any anesthesia. About 25 injection points are used for the undereye and bunny line regions.

Patients are always enthusiastic to reduce the lines in this region and very small doses of onabotulinumtoxinA are in fact required to do so. Avoid overinjecting this area as it is easy to develop the complications of enhanced eye bags or festooning, lid laxity, a swollen waterlogged appearance and the “inanimate lower eyelid.”

THE NECK AND JAWLINE

Microbotox is used here to elevate the jowls, smoothen the jawline, reduce the platysmal bands, reduce horizontal creases, decrease the crepelike appearance of the neck skin, and allow the neck skin to drape the cevicomental angle more acutely.

It does all of this by exerting its action on the sweat and sebaceous glands of the neck to smoothen and tighten the skin and on the platysmal muscle over its entire area as opposed to the technique of pinpoint injections to the platysmal bands alone. Elamax ointment applied to the whole neck for 20 minutes can be useful for patient comfort. Two to three syringes of onabotulinumtoxinA solution are prepared, each containing 24 to 28 units in 1 ml saline.

For the full Microbotox neck, the area of coverage should be from two fingerbreadths above the jawline to the clavicle below and from the preauricular region sweeping downward under the chin and across the midline (Fig. 6.8). If the patient only wants elevation of the jawline, then two syringes of onabotulinumtoxinA are sufficient with the injections starting above the jawline and sweeping down over the neck up to the level of the thyroid cartilage. The distribution of the Microbotox is therefore in the form of a sling going under the chin and upper neck. Here the injection points can be closer together. Over the sternocleidomastoid however, the injections should be spaced further apart to avoid weakening this muscle.

In those patients who have horizontal neck lines as their primary complaint, the injection points can be closer together along the lines themselves and in between the sternocleidomastoids but more dispersed over that muscle.

In all cases of neck and jawline Microbotox, care should be taken not to inject over the risorius or the depressor anguli oris as this can lead to an asymmetric smile or the lack of a full, broad smile.

If the patient also has horizontal neck lines and crepelike skin, then a third syringe of onabotulinumtoxinA can be used to resurface the entire anterolateral surface of the neck as well (Figs. 6.9 and 6.10). Microbotox of the neck and jawline is a good complimentary treatment to the onabotulinumtoxinA facial slimming technique for masseteric hypertrophy where the initial rapid shrinkage of the masseteric bulk can lead to a temporary laxity of the jowl and upper neck skin. The microbotox of the neck and jawline helps to alleviate this by relaxing the superficial platysma fibers and allowing the skin to redrape more closely to the cervicomental angle.

MICROBOTOX FOR OILY FACIAL SKIN, ACNE, AND LARGE PORES

In Asia, a common request is to smoothen the skin, decrease the incidence of acne over the cheeks and forehead and especially to reduce the appearance of large facial pores. While there are many other modalities that can help such as intense pulsed light, fractional lasers, chemical peels, and other nonablative laser systems. Microbotox has been an effective and efficient solution as patients can see visible results within a week (Fig. 6.11).

The usual areas addressed are the forehead and central T-zone as well as the nose and both cheeks below the infraorbital skin. This is where the facial skin is at its thickest and most greasy and where the pores are most visible.

For facial and nose sweat and sebaceous gland reduction, great care has to be taken to ensure small boluses of the onabotulinumtoxinA solution are injected into the dermis with as little spillover into the facial muscles as possible. For initial dosing of the forehead and T zone area 20 units in 1ml saline is sufficient to achieve a smoothening of the

male bodybuilder patients who request a smooth décolletage/chest area devoid of sweating. This makes the chest area smooth, dry, and satiny for posing and photographic purposes. One cubic centimeter with 28 units is sufficient for this area. Interestingly, in these patients, the decrease of sweating in this area has lasted up to 10 months.

The back of the hands can be injected in a similar way with one syringe of 28 units onabotulinumtoxinA in 1 ml per hand. This makes the skin of the dorsum smoother and more lustrous.

MICROBOTOX IN TRADITIONAL AREAS

An interesting spinoff of the microbotox technique has been that many patients now request Microbotox in the traditional areas of the crow’s feet, glabella, and central forehead regions, which otherwise would have received full-dose conventional onabotulinumtoxinA. These patients feel that the smoothness of the skin conferred by the Microbotox technique is more important than the muscle weakening effect and in fact would prefer to have more muscle movement than when they were being treated with full-dose onabotulinumtoxinA. They feel they look more natural.

MICROBOTOX IN SCARS AND KELOIDS

The author has for many years been using the Microbotox technique to treat fresh scars in order to speed up the resolution of the scar as well as to prevent keloid formation (7). Where there are established keloids, Microbotox injections have been especially useful and the technique will be described below. The use of onabotulinumtoxinA in scars is well established (8–12) but no reports exist so far in the use of onabotulinumtoxinA for keloids and hypertrophic scars.

While several papers have been written documenting the usefulness of Botulinum toxin type-A in the treatment of early scars or the

prophylactic prevention of visible scars developing (8–12), none actually describes the successful treatment of established hypertrophic or keloid scars with botulinum toxin type-A. The following chapter examines the author’s approach to treating keloids and the rationale in the development of the keloid triple therapy program, which includes the use of intense pulsed light (IPL), intralesional triamcinolone, and intralesional Microbotox injections.

Keloids remain a vexing problem to treat in any surgical field (19,20). In esthetic surgery in particular, the best surgical result can be unpredictably compromised by the development of a keloid and no amount of preoperative assessment can truly safeguard a patient from its development. A careful history of previous keloid development and an examination of past scars can help determine if a patient has a keloid tendency. The parents of the patient should also be asked if they are prone. Keloids may develop as a result of factors that may be within a surgeon’s control such as site and location of scar, the way in which the wound was closed, the sutures used, and whether postoperative immobilization was used so the surgeon can exert some influence over its development. Even then with all these precautions, a keloid may still develop and spoil an otherwise good surgical outcome. It is known that tension across a wound has a stimulative effect on the process of wound healing and can trigger the development of a keloid. Keloids in the sternum and over the deltoid regions are good examples of sites on the body where the wounds are subject to high skin tension forces across them and where the forces of nature can conspire to confound the surgeon.

Background Pathophysiology

This chapter does not attempt to delve into the detailed pathophysiology of keloids and the numerous research studies that are ongoing but a broad summary of current understanding (14–16) is in order to provide

a backdrop for why the triple therapy was devised and the rationale for using Microbotox.

Normal Physiology

Wound healing goes through three phases: the inflammatory, fibroblastic, and the maturation phases. In the first phase of wound healing, which is more correctly a wound “cleaning” phase, there is an inflammatory reaction both in the wound and in the surrounding tissues as numerous cellular elements such as red blood cells, eosinophils, mast cells, plasma cells, lymphocytes, and others are recruited to mop up and devour all the traumatized cells and debris in the vicinity as well as to accumulate the cells such as fibroblasts, which will subsequently take part in the repair process. The inflammatory cascade is triggered and vascularity increases to provide the conduits for cellular transport.

In the second phase, the repair cells such as fibroblasts and other cell precursors continue to aggregate and proliferate, producing hyaluronic acid, ground substance, collagen, smooth muscle myofibroblasts that are essentially the “glue” that holds the two wound edges together. This phase is one of rapid accumulation of higgledy piggledy disorganized cells and intercellular matrix and comes to a stop once there has been sufficient cellular accumulation and the wounds have closed.

In the maturation phase, all of these elements begin to organize and sort themselves out becoming linear sheets of collagen interspersed with the right amount of ground substance and the correct intercellular ratios. Muscles if they have been cut also begin to repair themselves as cellular differentiation occurs. This is a slower more long drawn out phase, taking several weeks to months to complete.

All of these phases are controlled by growth factors and cytokines with the usual chemical or hormonal start and stop signals functioning normally.

Abnormal Physiology

Most scars invariably go through an early phase where the wound is hypertrophic. This usually commences from the first 2 weeks after surgery and may last for several months. Here the scar is red, raised, mildly itchy and blanches to the touch but everything is confined to the wound itself. There is no encroachment of surrounding tissue. At a cellular level within the wound can be seen numerous nodules containing cells of collagen and plentiful smooth muscle myofibroblasts in the core of the scar but everything looks organized and neatly arranged. There is a moderate increase in basal collagen production but response to growth factors is still good. Clinically the hypertrophic scar responds to treatment with silicone gel, creams, massage, intralesional triamcinolone, and even intense pulsed light. Usually, three to four sessions of the above can suffice.

A keloid scar, however, behaves differently. It can follow from a hypertrophic scar or it can even develop months after a hypertrophic scar has subsided. It rapidly becomes raised, angry purple, hard, intensely itchy, or even painful to the touch and it grows beyond the confines of the original scar. In very aggressive cases, one can even see little fingers of advancing growth encroaching into the surrounding tissue. This is called the advancing edge of the keloid. The keloid may respond briefly to intralesional triamcinolone but invariably recurs after 3 to 4 weeks and patients have been known to be repeatedly injected for years—and even then with dismal results. Intense pulsed light may or may not work and numerous other treatments have been tried, which include interferon, radiation, cryotherapy, polytherapy, surgical excision, ultraviolet A1 radiation, 5-fluorouracil, Bleomycin, silicone gel sheeting, laser surgery, and pressure garments. The fact that there are so many different treatments only attests to the elusive and exasperating nature of the keloid.

At a cellular level, are seen large collagen (type 1) bundles, abundant eosinophils, mast cells, plasma cells, and lymphocytes, plentiful mucopolysachharide ground substance, high numbers of fibroblasts, fibronectin, elastin, and a high expression of proliferative cell nuclear antigen and ATP. In fact, it is as if the inflammatory and fibroblastic phases do not switch off and just continue with a disorganized cellular proliferation. It appears that the stop and start signals do not go off properly (21).

Current Thoughts on Keloid Formation

There are currently several theories behind keloid formation but the most attractive theory is that there is abnormal fibroblastic activity and decreased apoptosis of cells, i.e., increased production versus decreased destruction or breakdown. This in turn is caused by increased levels of growth factors and other cytokines. Why this happens is still not clear (17,18).

While a detailed description of the technique is beyond the scope of this chapter, the author has successfully used Microbotox in the treatment of keloids and scars. The technique is called triple therapy and combines intense pulsed light (IPL) to reduce redness and vascularity of the keloid, intralesional triamcinolone (Kanakort) injections to rapidly flatten the keloid and intralesional Microbotox to induce cellular apoptosis (13) as well as to reduce the tension of actin and myosin across the wound edges and thus reduce keloid relapse and recurrence.

Twenty-eight units of onabotulinumtoxinA in 1 ml saline or 1% Lignocaine is used for all cases of scar or keloid therapy. One cubic centimeter is sufficient to inject bilateral inframammary incisions for breast augmentation or a Cesarean wound. An abdominoplasty scar will require three such vials and an inverted-T breast reduction would require four syringes of the Microbotox preparation. Where the scars are fresh and not keloidal, only Microbotox is required.

Where there is an established keloid, this is first treated with several pulses of IPL using a 640 nm crystal filter. The Microbotox is then injected into the keloid as well as into the skin around the keloid. It is important to locate and inject the skin immediately adjacent to the advancing edge of the keloid. The triamcinolone (Kanakort) is then injected into the keloid until it blanches.

Microbotox has a synergistic effect with triamcinolone. It not only reduces the dose requirement of triamcinolone (which is important as the drug has potential side effects of telengiectasia and hypopigmented skin atrophy) but also reduces the often rapid recurrence of keloid formation while the patient is on intralesional injections of triamcinolone alone. It also has the effect of reducing the redness of the scar. A common observation when using triamcinolone alone at monthly interval is that the keloid reduces in size and intensity for 2 to 3 weeks and then starts to reactivate in the third or fourth week, often growing back to its original size. The physician then gives another dose of triamcinolone and the cycle starts again. With concomitant administration of the Microbotox, the recurrence is slower and less intense such that at the subsequent injection of triamcinolone, this dose can be directed wholly at the residual keloid rather than at a keloid, which has regained its original size. In this way, the keloid resolves at a faster rate and a more complete fashion.

Complications

As can be expected, the main complications of the Microbotox technique are in allowing the onabotulinumtoxinA to spread and diffuse into unintended areas, thereby causing weakness of certain muscles and altering facial movements and expression.

In the forehead, it is important to judge how much onabotulinumtoxinA is to be injected not only in terms of volume but dosage as well since this is a very variable area. In someone with a low narrow forehead, 1 cc may be too much volume whereas in a person with a high wide forehead, 1 cc is insufficient. It also depends on how skilled or dexterous the injector is. If too much is injected and diffuses deeply

into the frontalis muscle, then the patient can experience an immobile, low brow with difficulty in elevating the eyebrows and hooding of the lateral brow and loss of the upper eyelid crease.

Infraorbital complications have already been discussed in detail above. Again great care has to be taken during the injection to make sure the boluses are small and uniformly delivered.

In the neck, some patients can complain of weakness of the neck, especially on getting up from bed or in performing sit-ups. This occurs if there has been too much Microbotox injected over the sternocleidomastoid muscles. This can be avoided by either avoiding injecting over these muscles or increasing the spacing between the injection points to reduce the total load of onabotulinumtoxinA to that area. There have been no complications regarding phonation or swallowing.

At or above the jawline, if the injections are carried too far forward over the depressor anguli oris or too close to the risorius, then a weak or lop sided smile can result. Some patients feel they cannot smile broadly. This may be of concern and embarrassment to patients and may necessitate a small dose of Microbotox to the contralateral side to achieve symmetry. This same complication can be seen when injecting the cheeks for oil control and pore size reduction.

In general, it is best not to inject within two fingerbreadths from the angle of the mouth.

In the hands, a potential complication could be weakness of the intrinsic muscles but this has not been seen yet.

RESULTS

Case 1

A 49-year-old woman with greasy skin, open visible pores, popply chin, and glabellar frown lines requested a happier, vibrant look, and smoother skin so that her make up would stay on better and look more even. She received traditional onabotulinumtoxinA to her glabellar/eyebrow, crow’s feet, central forehead, and chin areas. Each black injection point is between 2 and 4 units. The forehead, infraorbital, and cheek areas were then chemoresurfaced with Microbotox (green areas) using two 1 ml syringes of onabotulinumtoxinA, each syringe containing 24 units in 1 ml saline and injected at 1cm regular intervals. 1 ml was used for each side of the face and forehead (Fig. 6.12A–C).

Case 2

A 37-year-old man complained of oily skin, large pores, and minor acne scars. He disliked the oily appearance and said that he had to constantly blot his face with facial tissues and this irked him. He received 24 units to the forehead and T-zone area and another 28 units to the infraorbital and cheek area. One week later, he was happy with the smooth and even texture of his skin (Fig. 6.13A–H).

Case 3

A 42-year-old woman complained of crepelike appearance of her neck skin, a “chicken skin” appearance, some vertical banding, and some horizontal striations. She had tried chemical peels and thermage with little success. She received a full Microbotox of the neck and jawline using three syringes, each containing 28 units of onabotulinumtoxinA. 0.7 cc in 1 ml of saline. Postinjection, she felt the skin was smoother, finer, tighter, the jawline was lifted and when she applied neck creams they now glided on and stayed on the neck skin more easily (Fig. 6.14A–E).

Case 4

This 33-year-old woman wanted the best possible result for her Cesarean scar. A small keloid scar on her left deltoid had been successfully treated by the author using triple therapy. At the time of delivery, the author closed the Cesarean scar in layers and then commenced triple therapy from the third postoperative week; 28 units of onabotulinumtoxinA mixed with a small amount of Xylocaine 2% (Microbotox) was injected into the mildly hypertrophic scar. IPL using a wavelength of 640nm was also used to decrease redness, and 0.2 ml of triamcinolone was injected at the same time. She came monthly for 5 sessions and, at completion of therapy 6 months after the first treatment, the scar was barely visible and completely soft (Fig. 6.15A–E).

Case 5

This was the author’s first case in which Microbotox was used to treat a keloid. A 16-year-old girl had suffered a laceration of her left neck following a bicycle injury. A large thick and painful keloid developed.

A previous surgeon treated it unsuccessfully with triamcinolone injections for several months and then resorted to excising the keloid. It recurred and the surgeon excised it once more only to see it recur yet again. More triamcinolone injections were administered with little success. The patient became extremely depressed, reclusive, and self-conscious, growing her hair to cover her neck. When she was first seen by the author in March 2003, the keloid was hard, large, and extremely tender. She had not received any treatment for 6 months. Intralesional triamcinolone was given weekly for three sessions, each session being traumatic for both patient and surgeon. It was then decided to inject Microbotox into the keloid and the surrounding skin to act as a “chemical splint” and combine this with the intralesional triamcinolone to potentiate its effects. As the keloid was very red and vascular, it was also decided to expose it to several pulses of IPL at 640 nm in order to decrease its color and vascularity. This triple therapy was performed under a short general anesthesia to aid

patient’s comfort. Twenty-eight units of Microbotox were administered in addition to 2 cc of triamcinolone. The patient was not seen till 11 months later when she returned for a second treatment. Most of the keloid had flattened, leaving only the superior edge still raised and slightly tender. A second treatment of IPL, 28 units Microbotox, and 2 cc triamcinolone were administered. One month later, there was complete flattening of the keloid. Over the next few months, the scar slowly improved in colour, texture, and softness until it appeared almost like normal skin (Fig. 6.16A–E).

DISCUSSION

The Microbotox technique has been an interesting and serendipitous discovery that has greatly expanded the scope of onabotulinumtoxinA practice in the author’s clinic. The initial observation of smooth, clear, and slightly edematous turgid forehead skin with a satiny sheen following administration of onabotulinumtoxinA to the forehead

lines led us to realize that this was due to the intradermal effect of onabotulinumtoxinA that had diffused out from the muscle into the skin. Patient requests to have this smooth forehead skin without loss of forehead movement and expression gave the author the idea to deliver the onabotulinumtoxinA directly into the skin and not into the muscle.

The aim was to deliver the onabotulinumtoxinA as multiple microdroplets into the dermal layer of the skin at carefully spaced out intervals. However, because the injection of the microdroplet was technically challenging and impossible to confine to the dermis alone, there was bound to be diffusion into the underlying superficial muscle layer, which would cause relaxation of the fibers of frontalis that insert into the dermis and not the deeper layers of the muscle. This would allow a smoothening of the skin without affecting the function of the deep muscle and hence elevation of the eyebrows.

If a conventional preparation of onabotulinumtoxinA using 2 to 2.5 ml of saline were used, then each microdroplet would contain a higher concentration of onabotulinumtoxinA and if these microdroplets were to inadvertently diffuse into the deeper fibers of the muscle, then widespread paralysis of that muscle would result, leading to unwanted muscle weakness especially in the lateral forehead. This would in turn cause flattening of the brow, possibly lateral eyelid hooding and patients could complain of a“stiff”feeling over the eyebrow/ forehead region.

The author therefore felt that if the concentration of onabotulinumtoxinA was reduced by further diluting it in the syringe so as to increase the total injection volume to 1 cc but retain the desired number of units (for example, 16, 24, or 28), then the actual dose of onabotulinumtoxinA to the skin would still be relatively high but with much less diffusion into the deep layers of the facial muscles. Only diffusion into the superficial

muscle fibers is desirable as it is this that gives the reduction of superficial and fine rhytides.

Practice with injecting the microdroplets was required to ensure a consistent and steady delivery of these microdroplets to the skin and superficial muscles of the target area. This practice was necessary as the markings of a standard 1 cc syringe are for 0.05 and 0.1 ml droplets only. With Microbotox, we are trying to achieve at least 10 microdroplets with every 0.05 ml. As described, this entailed squirting microdroplets of water onto a glass table top so as to correlate the amount of injection force with the emerging droplets. Developing this tactile sense was very useful as it also helped with a more precise delivery of onabotulinumtoxinA when using conventional 2.5 cc dilutions to the traditional areas.

The Microbotox technique was first used by the author for the improvement of forehead lines and for the fine lines under the lower eyelid. Patients were satisfied with the results in these two difficult areas to treat. Unwanted side effects of injecting normal dilution onabotulinumtoxinA into these areas were significantly reduced and patients gave enthusiastic feedback.

The author then started using the technique to allow better draping of the neck skin and elevation of the jowls and jawline by the intradermal effects on the skin as well as on the superficial fibers of the plastysma. Microbotox of the neck was also seen to be beneficial to reducing the intensity of the horizontal neck lines, another difficult to treat problem.

Once the delivery of microdroplets was consistent and predictable, it was natural to extend this technique to the skin of the T-zone,

nose, and cheeks to decrease sweat and oil secretion and ultimately improve the appearance of open pores. It was also noted that acne in this area improved and patients had a more desirable “matt” finish to their skin instead of the “greasy, oily” look, which necessitated constant blotting.

Microbotox to the décolletage, chest, and hands were again natural extensions of employing this technique.

The use of Microbotox in the treatment of scars and keloids has been particularly rewarding. It arose from the simple idea to use the onabotulinumtoxinA as a “chemical splint” to maximize the effect of the concomitant injections of intralesional steroid and has now become part of an established protocol of three modalities (including IPL) all administered at the same session. Currently the author injects all fresh surgical scars with Microbotox on the sixth or seventh postoperative day just prior to removal of stitches. If the scars are already keloidal, then triple therapy is commenced at the initial consultation and continued monthly until the keloid is resolved. This may require 4 to 8 sessions.

CONCLUSION

Microbotox has multiple uses in the face, neck, hands, and body as well as for scar and keloid therapy. It is a refinement in the use of onabotulinumtoxinA and has allowed us to understand better the myriad effects of onabotulinumtoxinA. It has greatly increased the versatility of an already versatile and fascinating drug.

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