Microstomia Treatment & Management

Updated: Nov 05, 2018
  • Author: Homere Al Moutran, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Medical Therapy

Burns and caustic injuries

Initial management of facial burns involves stabilization of the patient and management of the more life-threatening injuries that can occur from electrocution (eg, cardiac conduction problems, rhabdomyolysis, renal failure).

In patients with flame burns or caustic ingestion, consider the indication of endoscopy to evaluate the aerodigestive tract. However, since product safety laws have limited the pH extremes of household products, laryngeal and gastroesophageal injuries from caustic ingestion have become rare. Expectant management is now common, with clinical assessment dictating acute management and endoscopy reserved for patients who exhibit drooling; dysphagia; stridor; pain in the neck, chest, or abdomen; or other signs and symptoms suggestive of extensive damage.

Facial burns can be dressed with an antibiotic ointment such as bacitracin zinc. If damage extends intraorally, penicillin or another appropriate antibiotic can be administered to cover superinfection by oral flora. Early debridement of electrical burns is not generally advised, since damage and necrosis of the underlying muscle and soft tissues may extend beyond what is visible.

Important to note is that physicians should counsel patients and family members that bleeding from the superficial labial artery may occur after 5-7 days, with sloughing of the eschar. Patients with bleeding can also use a simple pinching maneuver of the thumb and finger until they can be seen by the physician.

Cutis, Raynaud phenomenon, esophageal dysmotility disorder, sclerodactyly, and telangiectasia syndrome

Hygiene measures and prophylactic treatment play a large role in the management of cutis, Raynaud phenomenon, esophageal dysmotility disorder, sclerodactyly, and telangiectasia (CREST) syndrome. Early institution of daily fluoride treatments and dental restorations can help maintain dentition. For patients with CREST syndrome, administer antireflux medication and advise patients to consume a less cariogenic diet (ie, avoid sugary foods and acidic drinks). Xerostomia is treated with either hydroxychloroquine sulfate (Plaquenil) or a combination of hydroxychloroquine sulfate and pilocarpine, which promotes salivary flow by a parasympathomimetic action. Chlorhexidine gluconate rinses can be used to treat the inevitable gingivitis, and the frequent oral candidiasis is treated with antifungals, as needed. If temporomandibular joint dysfunction is present, use nonsteroidal anti-inflammatory drugs for symptomatic relief.

Prevention and appliance therapy

In most patients with microstomia, the disorder develops over time. Patients with perioral burns or fibrosis of the skin may benefit from early intervention with a preventive appliance to reduce contracture as scarring and stiffness advance.

Various oral appliances that prevent microstomia have been developed. [8]   The appliances are classified based on the direction of the stretch (horizontal, vertical, circumoral) and placement (external and internal). Take into account the patient's age, dentition, and the location and depth of the pathologic condition when choosing an appliance. [9, 10, 11] For example, circumoral stretch is required in cases of circumferential burns or sclerosis that involves all of the perioral tissues. Devices that mold to the palate may be effective in adults and cooperative children, but, because infants usually require intact posterior dentition, they are generally not indicated for infants. Furthermore, infants may not keep the device in their mouth and are at risk of choking. For these children, the device may be secured with elastic headbands or, alternatively, with a molded face mask to hold the commissure hooks. Buckle paddles may be included if the cheeks are scarred and require expansion.

The microstomia prevention apparatus (MPA; see image below) is widely available, simple to use for physicians and patients, and does not require intact dentition. However, as with all devices, this apparatus has disadvantages. It does not prevent lower lip eversion when the scar is adjacent to the vermilion borders, a potential for skin breakdown exists, and the patient is unable to retain oral secretions.

Microstomia prevention apparatus (MPA). Microstomia prevention apparatus (MPA).

In cases of trauma, a splint should generally be instituted within 2 weeks of the injury. In general, the appliance is worn for 6 months; the patient may then transition to nighttime use only until the scar is mature. In some cases, the appliance is designed for repeated removal and insertion throughout the day.

In addition to preventive apparatus, the injection of chemical agents that inhibit fibroblast growth have shown potential in preventing scar formation. Exercise and massage improve patient outcome.

Safety laws have limited the pH extremes of household products, making caustic injuries rarer, but this does not eliminate the need for prevention through securing caustic items out of reach from children. Strategic placement of electrical cords is also imperative in reducing household accidents that lead to perioral burns.

Microstomia following resection of malignancies of the lips and mouth has become uncommon with modern reconstructive techniques. However, the surgeon must understand which reconstructive techniques lead to a smaller oral aperture. As a rule, surgical techniques that do not recruit tissue to compensate for the defect promote microstomia, while techniques that bring in additional tissue to compensate for resected lip, either by a pedicled or free flap, are less prone to shrinking the oral opening. In such cases, the microstomia may be complicated by radiation therapy.


Surgical Therapy

The surgical correction of microstomia is approached in 1 of 2 ways. The first is to re-create the corners of the lips (commissures), a procedure known as commissuroplasty or commissurotomy. This procedure is usually indicated when scarring from a burn has resulted in significant thickening or asymmetry of one or both commissures. [12] Although a number of modifications of this procedure have been developed, the essentials include reestablishing the intended location of the commissure, excising the scar tissue, and covering the area with mucosal flaps. Establishing an intact orbicularis muscle clinically prior to proceeding with scar excision is crucial.

Various reconstructive procedures for the commissures have been proposed, beginning with Dieffenbach in 1831. This technique involved the advancement of superior, inferior, and lateral mucosal flaps to reconstruct the corner of the mouth after removal of a triangular wedge of scar tissue. The procedure was modified by Converse and later by Friedlander et al and Mehra et al (see the first image below). [13, 14, 15] Gillies and Millard, and later Johns et al, used the vermilion flap of the corner of the mouth to reconstruct the upper lip; [3, 16] they also used oral mucosa from the inner aspect of the lower lip to form a new vermilion border (see the second image below).

Commissuroplasty, as performed by Converse (1959). Commissuroplasty, as performed by Converse (1959). (A) Skin excision designed to accommodate elongation of the commissure. (B) Skin excision performed and mucosal incisions diagrammed. (C) Mucosal flaps incised and mobilized. (D) Mucosal flaps sutured in place. (Reprinted from Converse JM and Wood-Smith D. Techniques for repair of defects of the lips and cheeks. In Converse JM, ed. Reconstructive Plastic Surgery, 2nd edition, volume 3. WB Saunders; Philadelphia:1977. pp.1574, with permission from Elsevier).
Commissuroplasty, as performed by Gillies and Mill Commissuroplasty, as performed by Gillies and Millard (1957). (A) Triangular skin excision designed to accommodate elongation of the commissure. A flap of vermilion is raised from the lower lip. (B) Vestibular mucosa is advanced externally to reconstruct the vermilion of the lower lip. (C) The vermilion flap is rotated and sutured laterally to reconstruct commissure. (Reprinted from Converse JM and Wood-Smith D. Techniques for repair of defects of the lips and cheeks. In Converse JM, ed. Reconstructive Plastic Surgery, 2nd edition, volume 3. WB Saunders; Philadelphia:1977. pp.1575, with permission from Elsevier).

The commissures may be lengthened with transposition flaps. Muehlbauer described a procedure using 2 Z-plasties that rotate 2 small skin flaps into the mucosa of the lip. [17] Fairbanks and Dingman used 2 small triangular flaps of mucosa, one with a superior base and one with an inferior base. [18] These flaps were dissected free and transposed for a lengthening effect while the buccal mucosa was advanced to the commissure and then sutured. The technique described by Fernandez-Villoria transposed inner and outer orbicularis oris muscle flaps and advanced oral mucosa to form the new vermilion. [19]

Berlet et al presented a technique designed to reduce the shortening effect seen during healing. [20] The shortened commissure is opened and mucosal flaps are rotated in to cover the raw surfaces. The lateral rotation of the flaps and the position of the intraoral closure theoretically result in a natural tendency of the flaps to pull laterally with healing. Jackson also used rotated rhomboid mucosal flaps to cover the raw surfaces after commissurotomy.

More recently, Turan et al described a single-rhomboid flap technique followed by a splint for 2 weeks. [21] They were able to achieve an increase from 37 mm to 55 mm after 8 months.

Makiguchi et al described the use of a nasolabial flap in the treatment of microstomia caused by burn-related cicatricial contracture, with no postoperative splinting required. [22]

The second approach to surgical correction of microstomia involves augmentation of the lips or commissures. This group of techniques is most useful in individuals with congenital microstomia or a small oral aperture due to surgical resection and reconstruction. The oral aperture may be widened with stair-step lengthening of the muscle in patients with a congenitally small orbicularis oris, such as those with Freeman-Sheldon syndrome (see the images below). Reconstruction using regional pedicled flaps and free flaps brings in distant tissue to expand the oral opening if inadequate tissue is present.

Schematic representation of orbicularis oris muscl Schematic representation of orbicularis oris muscle-lengthening procedure.
Schematic representation of orbicularis oris muscl Schematic representation of orbicularis oris muscle-lengthening procedure.

Tissue expanders are sometimes feasible in patients in whom extensive skin scarring has occurred but muscle is intact. Dynamic slings with temporalis muscle can be used to improve lip and commissure movement when muscle damage has occurred.


Preoperative Details

Before undertaking any procedure, document the degree of the microstomia with photographs, including views at rest and with muscle contraction (ie, smiling, puckering).



Document with follow-up photographs. Expansion devices can be considered if contracture of the oral aperture develops following surgical correction.



Aside from changes to cosmesis, the most common complication of microstomia is loss of dentition. Multiple causes are possible, including limited access, as well as other compounding factors such as xerostomia and, possibly, gastroesophageal reflux.

Complications of surgery for microstomia include difficult intubations, flap failure and necrosis, bleeding, infection, contracture with recurrent microstomia, and unfavorable cosmetic result at the mouth or donor site.

Patients with lip burns should be counseled that sloughing of the superficial eschar and resultant bleeding are common and can usually be controlled by pinching the lip between the fingers for 5-10 minutes.

When using oral expanders, excessive tension leads to ischemic necrosis, further tissue loss, and fibrosis.


Outcome and Prognosis

Treatment of oral commissure burns is reported in several series. With timely intervention, cosmesis and function can be favorably improved using prostheses alone or in combination with mucosal or muscle/mucosal flap reconstruction of the commissure.

Microstomia results variably from large-defect reconstruction following tumor resection, depending on the size and location of the mass and the reconstructive technique chosen. When selecting a reconstruction technique, the surgeon must consider the patient's desires, specifically, function and cosmesis. Although distant flaps reduce the risk of microstomia, they are usually accompanied by excessive bulk and poor skin color match. Revision surgery can be considered when necessary, keeping in mind the necessary vigilance for tumor recurrence.

The prognosis for patients with calcinosis cutis, Raynaud phenomenon, esophageal dysmotility disorder, sclerodactyly, and telangiectasia (CREST) syndrome varies considerably, with remitting and relapsing courses common. Tooth decay and loss are common but can be prevented or delayed with early intervention, aggressive oral hygiene, and antireflux management. Cosmetically, these patients develop masklike facies with smooth shiny skin and fibrosis of the facial muscles.


Future and Controversies

Controversy persists regarding the timing of reconstruction in patients with oral commissure burns. Although many authors advocate allowing scar formation and contracture to occur prior to excision and reconstruction, others argue for early reconstruction once tissue demarcation has occurred over several weeks. Additionally, some argue that oral expansion devices can actually cause hypertrophic scarring and rounding of a commissure and therefore should not be used alone in treatment of commissure burns. However, many agree that the use of expanders diminishes the likelihood of surgical reconstruction.

New reconstructive techniques for deficiencies of the lip and for microstomia continue to emerge. As management options multiply, so does the variety of opinions in regard to optimal management of patients with this condition.

Physicians treating patients with microstomia must always strive to balance function, cosmesis, donor site morbidity, and patient desires.