You are in: eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > RECONSTRUCTIVE SURGERY MicrostomiaArticle Last Updated: Feb 23, 2007AUTHOR AND EDITOR INFORMATIONAuthor: David Darrow, MD, DDS, Associate Professor, Departments of Otolaryngology-Head and Neck Surgery and Pediatrics, Eastern Virginia Medical School David Darrow is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American Academy of Pediatrics, American Bronchoesophagological Association, American Cleft Palate/Craniofacial Association, and American Medical Association Coauthor(s): Jamie Eaglin, BS, Eastern Virginia Medical School; Jeffrey D Carron, MD, Assistant Professor, Pediatric Otolaryngologist, Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center Editors: Hassan H Ramadan, MD, MSc, Professor and Vice-Chair, Department of Otolaryngology-Head and Neck Surgery, Professor, Department of Pediatrics, West Virginia University; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Gregory C Allen, MD, Assistant Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine; Christopher L Slack, MD, Otolaryngology-Facial Plastic Surgery, Private Practice, Associated Coastal ENT; Medical Director, Treasure Coast Sleep Disorders; Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine Author and Editor Disclosure Synonyms and related keywords: microstomia, small mouth, CREST syndrome, calcinosis cutis, Raynaud phenomenon, esophageal dysmotility disorder, sclerodactyly, telangiectasia syndrome, orofacial burns, Freeman-Sheldon syndrome, craniofacial dysplasia, whistling baby syndrome, Hallermann-Streiff syndrome, oro-palatal dysplasia, Fine-Lubinsky syndrome, hemifacial microstomia, small oral opening, diffuse facial scleroderma INTRODUCTIONHistory of the ProcedureMicrostomia is the term used to describe a congenital or acquired reduction in the size of the oral aperture that is severe enough to compromise cosmesis, nutrition, and quality of life. Prior to the 20th century, microstomia was usually seen in adults as the result of surgical resections of the lips for malignancies or other masses. In recent years, the development of improved surgical reconstructive techniques, particularly the transfer of regional flaps and vascularized free tissue, has made this disorder increasingly rare among adults who undergo lip resections. As a consequence, microstomia due to connective tissue disorders has become more important in adults. During the early 1900s, electrical service became available to most Americans, and lye and other caustic substances were introduced into many homes as household cleaners. Coincidentally, microstomia due to accidental burns and subsequent scarring around the mouth was noted to affect an increasing number of children. Despite federal legislation that mandated protections incorporated into both electrical wiring and packaging for caustic materials, such accidents remain a frequent cause of microstomia among children. Advances in prosthetic dentistry over the past 30 years have improved early management of pediatric patients with oral burns, but surgical correction is also occasionally necessary. Less commonly, genetic disorders are associated with microstomia. Earlier identification of children with this syndrome has resulted in avoidance of complications and early intervention when necessary. ProblemIndividuals with microstomia may experience limited oral intake, articulation problems, and difficulty inserting dental appliances. Additionally, a small oral opening results in restricted access for routine oral hygiene. The severe tooth decay that may follow is then compounded by limited access for the dentist, possibly delaying treatment and leading to more extensive odontogenic infections. As a result, head and neck surgeons should be familiar with the management of microstomia and, more importantly, with its prevention. FrequencyThe incidence and prevalence of microstomia are difficult to determine since no established criteria for diagnosis is available. In addition, no code for microstomia is listed in the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), and, therefore, database searches may be inaccurate. With the development of innovative flap techniques and microvascular free tissue transfer, microstomia following oral cavity tumor extirpation has become an uncommon condition. However, reports have shown that that 3.7-10.8% of thermal burn admissions and more than 30% of diffuse facial scleroderma cases are complicated by microstomia. Microstomia related to congenital syndromes is less common. EtiologyIn toddlers, orofacial burns occur when the child sucks on the female end of a live extension cord or the junction of two cords. The relatively high electrical resistance of the skin reduces injury to the skin and more distal structures; however, the low resistance of saliva-coated mucosa results in significant injury to the oral tissues. The lower lip is usually damaged more extensively than the upper lip, with most of the injury occurring at the vermilion border of the oral commissures. Caustic injury from suicide attempts, assaults, and accidental ingestions can also cause chemical burns and resultant scarring. Lye and industrial cleaning solutions are the predominant items associated with suicide attempts and accidental ingestions that cause such burns. Since the advent of product safety laws, bleach and other household products rarely have a pH level greater than 12, and the resulting injuries are far less serious than in the past. Conversely, sulfuric acid from car batteries has reportedly been used as a weapon in domestic abuse cases. Burns of the lips may also result from explosions of volatile liquids, which spray a patient's face with burning fuel before he or she has time to react. Although uncommon, splash burns from flaming foods and alcoholic drinks have also been reported. Microstomia is common following resection of masses of the lips; however, the problem is usually not functionally significant unless at least half of the lip is involved. When the lesion is small, wedge resection is usually used, resulting in functionally normal lips and oral vestibule. However, large resections of the lip that require local advancement and transposition flaps, such as those described by Gillies, Karapandzic, Estlander, and Abbe, use only the remaining lip tissue and often result in microstomia severe enough to cause functional compromise. Flaps that mobilize cheek or mental area tissue (ie, Grimm or Bernard reconstructions), incorporate pedicled distal tissue (ie, pectoralis myocutaneous flap and deltopectoral flap), or bring in vascularized free tissue (radial forearm or fibula free flaps) are less likely to result in narrowing of the oral aperture. Autoimmune disease, mainly the calcinosis cutis, Raynaud phenomenon, esophageal dysmotility disorder, sclerodactyly, and telangiectasia (CREST) syndrome variant of scleroderma, can cause microstomia through contracture from severe sclerosis of the facial skin. Patients with this disorder are at high risk for dental problems due to poor oral access that are exacerbated by temporomandibular joint dysfunction. These patients also have xerostomia, which places teeth at further risk due to loss of the protective effects of saliva. Decreased salivary flow and limited tongue mobility from fibrosis often leads to dysphagia. Ischemic changes in the gingiva lead to recurrent gingivitis and mobile teeth. Furthermore, gastroesophageal reflux, part of the esophageal dysmotility of CREST syndrome, promotes erosion of the enamel layer of the teeth. A few congenital and inherited disorders have been associated with microstomia. Perhaps the most dramatically small mouths appear in children with Freeman-Sheldon syndrome (ie, craniocarpotarsal dysplasia, whistling baby syndrome). Other disorders that may cause microstomia include Hallermann-Streiff syndrome, oro-palatal dysplasia, Fine-Lubinsky syndrome, restrictive dermopathy, types of epidermolysis bullosa, and, occasionally, Down syndrome and hemifacial microsomia (see Images 1-3). PathophysiologyOral burns are generally third degree, with a central area of necrosis surrounded by a pale elevation of the skin. The adjacent skin is usually hyperemic. In electrical burns, soft tissue injury is typically more extensive than initially appreciated, as the current follows the low-resistance paths of muscle, nerves, and blood vessels. Coagulation necrosis occurs, followed by a period of coagulative necrosis with inflammation of adjacent vital tissues. Over several weeks, the necrotic cells are removed by fragmentation and phagocytosis of the cellular debris by scavenger white cells and by the action of proteolytic lysosomal enzymes brought in by the immigrant white cells. Eventually, fibroblast formation and collagen deposition occur, along with scar tissue formation and contraction. In scleroderma, endothelial alterations lead to stimulatory changes that involve many cells, including fibroblasts, T lymphocytes, macrophages, and mast cells. The activated cells secrete various substances that lead to deposition of extracellular matrix compounds, including fibronectin; proteoglycans; and collagen types I, III, V, and VII, in the skin and other tissues. The degree of sclerosis increases when profibrotic cytokine–induced fibrosis is also present. ClinicalThe cause of microstomia in affected patients can usually be determined by the clinical history. Microstomia caused by disorders that are likely to chronically and progressively involve the perioral tissues must be differentiated from microstomia due to trauma or surgical scar that is characterized by a more correctable narrowing of the oral aperture. Microstomia due to the latter is more likely to be corrected with surgery. Patients affected by isolated microstomia may be socially isolated for long periods before presentation to a physician because of their appearance. Asymmetry, lack of proportion, excessive dental show, and altered geometric shape can produce a mouth that draws the curious stares of others. As with other facial deformities, microstomia can render a patient socially disabled. Often, patients with microstomia present with functional problems. Articulation abnormalities can lead to impaired communication. Patients may report difficulty brushing their teeth or inserting dentures. Some affected individuals may be referred by their dentists, since a limited oral opening can impair cleaning teeth and complicate extractions or restorative procedures. Caloric intake is limited only when the oral aperture size is drastically reduced. Patients with scleroderma may present with dysphagia or involvement of other systems before the oral aperture is affected. INDICATIONSIntervention in microstomia is indicated early following burns and other perioral trauma to reduce complications due to scarring. Such early intervention generally involves some sort of appliance therapy. In patients with microstomia of longer duration, impairment of functions such as those described in the Clinical section, including speech, swallowing, and oral hygiene, are indications for intervention. Patients should also be considered for management of their microstomia if the deformity is socially disabling. RELEVANT ANATOMYMicrostomia is affected predominantly by restriction of the labial skin and mucosa or the orbicularis oris muscle. Occasionally, vertical excursion is also limited because of scarring of the tissues of the cheeks. The lips are composed of skin and mucosa that are not supported directly by any rigid framework. Externally, the facial skin extends to the vermilion border. Internally, the lips form the anterior boundary of the oral vestibule; here, they are lined with oral cavity mucosa that harbors minor salivary glands. The upper lip is bounded superiorly by the nose and is divided into 3 subunits, the philtrum and 2 lateral subunits that extend from the philtral columns to the melolabial folds laterally. The lower lip is one functional subunit that extends to the labiomental fold inferiorly and to the melolabial folds laterally. The orbicularis oris is a circular muscle innervated by branches of the facial nerve. Its function is important in maintaining oral competence, normal speech articulation, and facial expression. The deep fibers of the orbicularis oris are oriented horizontally and act to compress the lips and to provide sphincter function, whereas the superficial fibers are responsible for finer movements. The oblique fibers act to evert the lips. The depressors of the lip include the depressor anguli oris, mentalis, depressor labii inferioris, and the platysma. The elevators of the lip include the levator anguli oris, zygomaticus, and risorius. Many of these muscles converge at the oral commissures, or corners of the mouth. Because the orientation of the muscle fibers at these locations is so variable, motion of the lip is normally most restricted at the commissures, and these areas are most severely affected by scarring and fibrosis in microstomia. Sensory innervation to the upper lip is primarily via branches of the infraorbital nerve (cranial nerve [CN] V2), and innervation to the lower lip is via the buccal and mental branches of the mandibular nerve (CN V3). Innervation to the commissures is primarily from the buccal branch of the mandibular nerve. The superior and inferior labial branches of the facial artery provide blood supply to the lips, and venous drainage is through corresponding veins that drain into the anterior facial vein. These vessels form a vascular ring that encircles the oral aperture. The lymphatic drainage of the lips is by cutaneous and mucosal lymphatics. The lateral portion of the lower lip drains into the submandibular lymph nodes; the central portion is drained by the submental lymph nodes. Lymphatic anastomoses between the 2 halves of the lower lip lead to bilateral drainage of the central portion. In contrast, the upper lip has little bilateral drainage, with lymphatics that lead to the preauricular, infraparotid, submandibular, and, sometimes, the submental lymph nodes. CONTRAINDICATIONSOral appliances are generally ill advised for patients with epidermolysis bullosa, since they are likely to induce further oral trauma and ulceration. Surgical correction of microstomia caused by lip resection for cancer should be delayed long enough to be certain the risk of recurrence is minimal. Such surgery is not advised for patients with the calcinosis cutis, Raynaud phenomenon, esophageal dysmotility disorder, sclerodactyly, and telangiectasia (CREST) syndrome because of the likelihood of poor tissue healing. WORKUPLab Studies
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TREATMENTMedical therapyBurns and caustic injuries Initial management of facial burns involves stabilization of the patient. In patients with electrocution injury, burns at the exit site of the current (ie, feet, buttocks) should be excluded. In addition, more life-threatening injuries can occur from electrocution (eg, cardiac conduction problems, rhabdomyolysis, renal failure). In patients with flame burns, consider endoscopy to exclude inhalation injury to the aerodigestive tract. In cases of caustic ingestion, hospital admission and early endoscopy were once considered mandatory. 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. 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 Pharmacotherapeutics 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. 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. 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 4) 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. 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 therapyThe surgical correction of microstomia is approached in one of two ways. The first is to release the lips at the 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. 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 Image 5). Gillies and Millard, and later Johns et al, used the vermilion flap of the corner of the mouth to reconstruct the upper lip; they also used oral mucosa from the inner aspect of the lower lip to form a new vermilion border (see Image 6). 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. Fairbanks and Dingman used 2 small triangular flaps of mucosa, one with a superior base and one with an inferior base. 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. Berlet et al presented a technique designed to reduce the shortening effect seen during healing. 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. 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 Images 7-8). Reconstruction using regional pedicled flaps and free flaps brings in distant tissue to expand the oral opening if inadequate tissue is present. Preoperative detailsBefore undertaking any procedure, document the degree of the microstomia with photographs, including views at rest and with muscle contraction (ie, smiling, puckering). Follow-upDocument with follow-up photographs. Expansion devices can be considered if contracture of the oral aperture develops following surgical correction. COMPLICATIONSAside 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 PROGNOSISTreatment 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 CONTROVERSIESSome controversy exists 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 strive for a balance between function, cosmesis, donor site morbidity, and patient desires. As more innovations are introduced and published, a consensus may develop regarding preferred treatments for microstomia. MULTIMEDIA
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