You are in: eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > TRAUMA Parotid Duct InjuriesArticle Last Updated: May 21, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Jose E Barrera, MD, Instructor, Department of Otolaryngology-Head and Neck Surgery, Stanford University Jose E Barrera is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, and American Academy of Sleep Medicine Coauthor(s): Don R Revis Jr, MD, Consulting Staff, Department of Surgery, Division of Plastic and Reconstructive Surgery, University of Florida College of Medicine; Michael Brent Seagle, MD, Associate Professor, Division of Plastic Surgery, University of Florida College of Medicine; Consulting Staff, Florida Surgical Center Editors: Daniel G Becker, MD, Clinical Associate Professor, Department of Otorhinolaryngology-Head and Neck Surgery, Division of Facial Plastics and Reconstructive Surgery, University of Pennsylvania; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Robert M Kellman, MD, Professor and Chair, Department of Otolaryngology and Communication Sciences, State University of New York, Upstate Medical University; 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: parotid duct injuries, Stenson duct injuries, salivary gland, parotid fistula, sialocele, parotid duct, Stenson duct, parotid gland, salivary gland injuries, salivary gland injury INTRODUCTIONSection 2 of 11
  The parotid duct, or Stenson duct, is the major duct of the parotid gland, which is the major salivary gland. This duct serves as a conduit for saliva between the substance of the parotid gland and the oral cavity. Injury to the parotid duct may be difficult to diagnose; therefore, the initial examining physician must have a high index of suspicion for injuries occurring in the parotid region. Consultation with a specialist should occur if any question as to the integrity of the parotid duct exists. Successful treatment depends on early recognition and appropriate early intervention. Sequelae of inadequate diagnosis and treatment include parotid fistula and sialocele formation, which are inconvenient for the patient and more difficult to treat than the initial injury. Three operative techniques have been popularized over time. These include repair of the duct over a stent, ligation of the duct, and fistulization of the duct into the oral cavity. Radiation has been used in the past to suppress the gland, but use of radiation for benign disease is now avoided. Some authors advocate use of anticholinergics to suppress glandular function during healing, but this is not a frequently used modality. History of the ProcedureParotid duct injuries have been described in the literature for several hundred years, and published surgical treatments of parotid duct injuries began to appear in the 1890s. Nicoladoni reported the first primary anastomosis of the parotid duct in 1896.1 Morestin reported ligation of the proximal stump in 1917, and formation of an oral fistula was described in 1918.2 Experience in the care of parotid duct injuries greatly increased with the outbreak of World War I, which witnessed many penetrating facial injuries. Many present treatment modalities were developed during the war years. FrequencyApproximately 0.21% of patients with penetrating trauma in the parotid region experience an injury to the parotid duct. Males are twice as likely to experience parotid duct injury as females, a fact probably related to the more aggressive behavior of males. The mean age of patients with parotid duct injury is approximately 30 years. Etiology
ClinicalHistory A careful detailed history is necessary to facilitate communication between various health care professionals involved in the care of the patient and to document why the plan of care was appropriate. Patients with damage to the parotid duct often have multiple injuries requiring cooperation of several medical specialists. Important aspects of the natural history of the wound include the circumstances surrounding the injury, precipitating event or activity, exact mechanism of injury, time of occurrence, location of occurrence, and treatment initiated prior to presentation. Important signs or symptoms related to the wound include pain, fever, edema, discharge, and/or odor. Other important aspects of the history include tobacco, alcohol, or recreational drug use; medications or allergies to medications; tetanus immune status; ability to comprehend the magnitude of injury; and ability to cooperate with the treatment plan. Comorbid conditions that may place the patient at a higher risk for infection or its sequelae include diabetes mellitus, prior splenectomy, liver disease, immunosuppression, and presence of a prosthetic valve or joint. Physical examination A thorough physical examination is necessary in order to evaluate the overall state of health, comorbidities, nutritional status, and mental status of the patient. Following the general physical examination, turn attention to the wound. Assessment of the wound can be quite difficult and is often inaccurately or inadequately performed. Adequate examination of the wound may require administration of intravenous or oral pain medication to ensure patient comfort. Children, intoxicated individuals, and individuals with mental disabilities may require general anesthesia to allow adequate wound examination. Important aspects of wound assessment are listed below.
Photographs are a wise addition to the documentation present on the chart. INDICATIONSSection 3 of 11
See Treatment. RELEVANT ANATOMYSection 4 of 11
The parotid glands are the largest salivary glands. The paired parotid glands are formed as epithelial invaginations into the embryologic mesoderm and first appear at approximately 6 weeks' gestation. The glands are roughly pyramidal in shape, with the main body overlying the masseter muscle. The glands extend to the zygomatic process and mastoid tip of the temporal bone and curve around the angle of the mandible to extend to the retromandibular and parapharyngeal spaces. The gland is divided into superficial and deep lobes with regard to its relation to the facial nerve (ie, cranial nerve VII), which travels through the gland. This division is not truly anatomic but rather is used to facilitate surgical treatment of parotid masses. The facial nerve exits the cranium via the stylomastoid foramen and courses through the substance of the parotid gland. The superficial lobe of the parotid gland rests superficial to or lateral to the facial nerve, and the deep lobe rests deep to or medial to the facial nerve. The facial nerve branches within the substance of the parotid gland in a highly variable pattern. The parotid duct is approximately 7 cm long and is composed of an inner epithelium, a smooth muscle coat, and an outer adventitial layer much like a blood vessel. The parotid duct exits the parotid gland anteriorly and crosses the superficial border of the masseter. It then turns medially and pierces the buccinator muscle. After traveling for a variable distance between the buccinator muscle and the oral mucosa, it enters the oral cavity through a papilla in the buccal mucosa opposite the second maxillary molar. The course of the parotid duct generally follows a line drawn from the tragus to the midportion of the upper lip. Any injury that crosses this line should be considered to involve the parotid duct until proven otherwise. Parotid duct injuries are often overlooked because of more severe concomitant injury or difficulty in obtaining the diagnosis. The parotid duct travels adjacent to the buccal branch of the facial nerve and the transverse facial artery, which also are at risk in injuries causing damage to the parotid duct. The parotid duct was found to be interrelated with the buccal fat pad in cadaveric dissections. In addition, a 26% chance of injuring the parotid duct exists with the removal of the buccal fat pad. The transverse facial artery, if injured, need not be repaired. However, injury to this artery may cause bleeding into the tissues, which may obscure adequate delineation of structures and confuse the diagnosis. Above all, blind clamping of bleeding vessels in the wound is strongly discouraged because of the extremely high risk of further damage to the delicate structures in this area. An injury classification system has been devised for parotid duct injuries. This system divides the parotid duct into the following 3 regions:
CONTRAINDICATIONSSection 5 of 11
Wounds older than 24 hours should probably be managed expectantly because many heal without untoward event. WORKUPSection 6 of 11
Lab StudiesPerform appropriate preoperative laboratory studies as dictated by patient's age, sex, and overall medical condition. Imaging Studies
Other Tests
TREATMENTSection 7 of 11
Medical therapyWounds in the parotid region generally heal well with a low rate of infection, but patients with wounds that involve the oral cavity or require manipulation of the parotid duct through the oral cavity should probably receive prophylactic antibiotics for a brief time after primary closure. Saliva containing as many as 100,000,000 organisms per mL and representing as many as 190 different species may be inadvertently introduced to the wound. These species are both aerobes and anaerobes, and several of the more common species produce beta-lactamase, rendering them resistant to penicillin. Routine cultures are not necessary because they are costly, demonstrate no growth in over 80% of cases, and rarely alter first-line therapy. Moreover, wounds subsequently manifesting signs of infection often have bacteriologic profiles differing from the initial cultures. Wound care is the cornerstone of therapy; antibiotics cannot avert or cure infections in the setting of poor wound care. In regards to antibiotic therapy, err on the side of caution because the risk of antibiotic therapy is minimal, while the potential complications of wound infections are considerable. Prophylactic antibiotics should be continued for 5-7 days. Selection of the appropriate antibiotic involves multiple factors, including culture results if obtained and available, drug sensitivities, patient age, drug interactions, expected compliance, and renal and hepatic function. The drug of choice is amoxicillin/clavulanate potassium (Augmentin; adult dosage 500/125 mg PO tid or 875/125 mg In rare cases, human saliva has been shown to contain and occasionally transmit Clostridium tetani. Assess all patients for tetanus immune status and update their immunization as appropriate. Err on the side of caution when deciding to administer tetanus toxoid or tetanus immune globulin. Some authors choose to employ anticholinergic agents to suppress glandular function during healing or in an attempt to close a fistula or resolve a sialocele spontaneously. A commonly used agent is propantheline bromide (Pro-Banthine), which inhibits the action of acetylcholine at the postganglionic nerve endings of the parasympathetic nervous system (adult dose 15 mg Surgical therapyMeticulous wound care is the cornerstone of treatment for penetrating injuries in the parotid region. Copious irrigation has been shown to decrease the incidence of wound infection. Use isotonic sodium chloride solution, dilute Betadine, or dilute hydrogen peroxide to cleanse the wound thoroughly. Irrigation is best performed with a 10-mL syringe with an 18-gauge angiocatheter attached. Take care to avoid injection of the tissues and to prevent additional trauma. Careful debridement of devitalized tissue, particulate matter, and clot is necessary to reduce the infection risk and to improve the cosmetic result. Clean, surgically created wound margins allow for faster wound healing and better scarring. Head and neck wounds, being in a cosmetically sensitive area, may be closed if they are less than 12 hours old and not obviously infected. These have been closed with a low incidence of infection. The low infection rate is probably related to the excellent regional blood supply and infrequency of edema in these areas. Perform closure in a simple interrupted fashion, avoiding layered closure with buried sutures. Preoperative detailsAppropriate consent must be obtained, including an explanation of the possible need for duct repair, ligation, or reimplantation into the oral mucosa. Informed consent includes a discussion of the possible complications, including but not limited to infection, hematoma, hypertrophic scarring, nerve injury, parotid fistula, sialocele, and death from anesthesia. Discuss expectant care with the patient as a viable alternate course of treatment that is probably less than ideal. Repair at initial presentation is technically simpler than in the case of delayed presentation with development of complications such as a fistula or sialocele. Administer 1 dose of intravenous broad-spectrum antibiotics within 1 hour prior to the operation. Intraoperative detailsAfter initiation of general anesthesia, prepare and drape the head and neck in the usual sterile fashion. Plan the initial incision based on the level of suspected injury indicated by preoperative examination of the wound, the oral papilla, and cannulation of the duct with a silastic tube. All but the most distal injuries require a standard approach to the parotid gland. Distal injuries may sometimes be appropriately approached through an intraoral buccal mucosal incision, and often the facial wound is extensive enough to allow adequate visualization of key structures and their repair. The most important initial step is the identification of the buccal branches of the facial nerve and the parotid duct itself. If the buccal branch was transected, repair it with fine sutures (8-0 to 10-0 nylon is appropriate) under microscopic aid. Use of a nerve stimulator intraoperatively and avoidance of the use of paralytic agents by the anesthesiologist can greatly aid in identification of facial nerve branches. The distal end of the parotid duct is identified by the silastic tube, which was placed via cannulation of the intraoral papilla. The proximal parotid duct can usually be identified by the flow of saliva into the wound. If not clearly identified, gentle pressure over the gland may cause an increased flow of saliva, facilitating identification. Once all key structures are identified, a decision is made regarding which repair technique to employ. Distal lacerations, occurring at site C, may be treated in several ways. If the papilla is uninjured, the proximal portion may be dissected free and reimplanted into the papilla. The papilla may be gently dilated if this technique is chosen. Alternatively, if the papilla is injured or if the proximal duct does not reach the papilla, the duct may be reimplanted into the oral mucosa posterior to the papilla. This should be performed with fine interrupted absorbable sutures with meticulous approximation of duct epithelium to oral mucosa. This should probably be performed under loupe magnification because of the difficulty of using the surgical microscope deep in the oral cavity. If the distal injury does not leave enough duct to be reimplanted into the oral mucosa without undue tension, then the best decision is to ligate the proximal duct. Injuries occurring over the masseter muscle, at site B, are the most common injuries to the parotid duct and may be treated by repair or ligation. Perform primary repair if enough length remains. Trim the edges cleanly and perform anastomosis over the silastic stent. A single layer of interrupted fine sutures (8-0 to 10-0 nylon or similar suture) is used to carefully reapproximate the severed ends with the surgical microscope or under loupe magnification. If a portion of the duct is damaged beyond repair or is missing, the proximal and distal duct should be ligated. Reports of attempts to use a vein graft to replace missing or damaged segments of parotid duct have generally found such attempts unsuccessful. Injuries of the proximal duct near the parotid substance, at site A, are usually best treated by ligation of the duct. The amount of proximal duct remaining is usually insufficient to result in a useful repair. Laceration of the gland itself without disruption of the parotid duct may be oversewn with fine absorbable sutures (5-0 or 6-0 Vicryl). If the surgeon is able to repair the duct over a stent, the stent is trimmed at the level of the oral papilla and sewn to the oral mucosa or around the maxillary second molar with a chromic suture. This is designed to hold the stent in place for the recommended 2-3 weeks while the injured duct heals and to help prevent stenosis at the repair site. It may also prevent postoperative edema in the region from collapsing the fragile duct. Patient tolerance of the stent is highly variable. Some patients require stent removal early or remove it themselves without untoward consequence. Most authors recommend a drain in the bed of the wound. This serves to drain any residual salivary leak and prevents early sialocele formation. Drains are removed once drainage is minimal and the skin has become adherent to the operative site. The remaining facial and intraoral lacerations, as well as any incisions required for exposure, are then closed in the standard fashion. Postoperative detailsPlace a compression dressing over the operative field postoperatively for several days. Perform routine drain care. Continue antibiotic prophylaxis for 5-7 days. Antibiotic prophylaxis may be administered orally to prevent retrograde infection if the duct has been repaired over a stent that protrudes into the oral cavity. If ductal injury required ligation of the proximal duct, expect marked temporary swelling of the gland followed by rapid glandular atrophy. If leaking of saliva occurs as in the development of a fistula or sialocele, a pressure dressing should be continued or reinstituted. Intermittent aspiration of sialoceles has led to resolution in many cases. Anticholinergics may be used to temporarily decrease salivary flow in order to effect wound healing. Others have reported dividing the tympanic branch of the glossopharyngeal nerve (ie, Jacobsen nerve) as it runs through the middle ear. This serves to interrupt the preganglionic secretomotor fibers to the parotid gland. This measure only temporarily reduces salivary flow, but it may provide enough time for spontaneous closure of the salivary leak. Follow-upNo special follow-up is necessary over and above routine postoperative care. COMPLICATIONSSection 8 of 11
Complications may result from inadequate initial diagnosis and treatment or following appropriate care. Persistent salivary fistula may be most troubling to the patient. If fistula occurs in the oral cavity, it is of no consequence and requires no further therapy. If the fistula occurs to the overlying skin, the patient experiences saliva dripping down the cheek. Initial expectant management, with or without anticholinergic medications, has led to resolution in many cases. Other cases have required surgical excision of the fistula tract with repair of the duct as previously described. Some have even required superficial parotidectomy for resolution. Anticholinergics may be beneficial in the treatment of fistulas. Sialocele, ie, a collection of saliva beneath the skin, may occur if the duct leaks but no fistula forms. This may also result when the glandular substance of the parotid is disrupted but the parotid duct is intact. This condition usually resolves with intermittent aspiration and compression and rarely requires drain placement. Anticholinergics may be beneficial in the treatment of sialoceles. Duct ligation may lead to early edema of the gland with accompanying pain from stretching of the capsule. This usually subsides spontaneously within 1-2 weeks as atrophy of the gland occurs. Late complications of ligating the duct include chronic infections of the remaining glandular substance. Sialadenitis may result from manipulation of the intraoral papilla or from sialography and may require drainage and antibiotics. Facial nerve injury and sensory nerve injury are well-recognized complications of surgery conducted in the region of the parotid duct, particularly in cases where trauma and blood extravasation have discolored the tissues and disrupted tissue planes. FUTURE AND CONTROVERSIESSection 9 of 11
Some controversy exists regarding optimal treatment of isolated parotid duct injuries. Most authors agree that the treatment of choice is immediate repair over a stent whenever possible, and certainly this is indicated if other injuries, such as facial nerve injuries, are present and require surgical intervention. At least one study, however, documents successful expectant treatment of isolated parotid duct injuries.5 Immediate repair may prevent some complications, such as fistula or sialocele formation, but it also places the patient at risk for other complications, such as iatrogenic facial nerve injury, even in experienced hands. Exploration and repair also involves significantly increased costs because this requires surgery and inpatient care, whereas expectant care is managed on an outpatient basis. On the other hand, a missed injury requires treatment that is also costly—not just financially but also in terms of quality of life. The responsible physician must decide which treatment plan is appropriate to each unique patient-care situation. Certainly, wounds older than 24 hours should probably be managed expectantly because many will heal without untoward event. MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Article Last Updated: May 21, 2008 | ||||||||||||||||||||||||||
