eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > Trauma

Parotid Duct Injuries: Treatment

Author: Jose E Barrera, MD, Instructor, Department of Otolaryngology-Head and Neck Surgery, Stanford University
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
Contributor Information and Disclosures

Updated: May 21, 2008

Treatment

Medical Therapy

Wounds 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 PO bid). It is the most effective and economical choice for outpatient therapy, unless contraindicated because of penicillin allergy. Doxycycline is an alternative choice for oral therapy in patients allergic to penicillin (adult dosage 100 mg PO bid). Rocephin 1 g administered intramuscularly or intravenously is useful in patients whose compliance with dosage schedules is questionable.

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 PO qid half an hour prior to meals).

Surgical Therapy

Meticulous 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 Details

Appropriate 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 Details

After 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 Details

Place 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.

In the case of a chronic parotid duct fistula, an intraoral diversion technique to reestablish salivary flow in the setting of a nonfunctional parotid duct punctum has been described. In this case report, a fistula tract and the surrounding ellipse of skin were passed in the oral cavity and sutured to the buccal mucosa with 4-0 chromic sutures.³ This allows for correction of a chronic fistula and simultaneous revision of a traumatic scar without need for stenting.

Alternatively, chronic fistula and sialocele have been medically managed with botulinum toxin type A.⁴ In this case, the authors injected only 100 IU divided among 3 injection points in the superficial part of the parotid to stop salivary secretion. After 5 days, the sialocele disappeared and subsequent problems were related to the scar. Three months later, because of the reappearance of facial tension and the initial effectiveness of this dosage, 100 IU of botulinum toxin were again injected. Maintenance injections of 100 IU were performed every 3 months.

Follow-up

No special follow-up is necessary over and above routine postoperative care.

Complications

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.

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