Учебники / Textbook and Color Atlas of Salivary Gland Pathology - DIAGNOSIS AND MANAGEMENT Carlson 2008

286 Non-salivary Tumors of the Salivary Glands

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Outline

Introduction

Penetrating Injuries

Trauma to the Gland

Salivary Fistula

Sialocele

Nerve Injury

Frey’s Syndrome

Hollowing

Trauma to Salivary Gland Ducts

Transection

Stenosis of the Duct

Radiation Injury

External Beam

Radioactive Iodine

Barotrauma

Summary

References

Introduction

The salivary glands may be subjected to a number of injuries and insults. Trauma to the parotid is relatively rare, noted to be present in only 0.21% of patients in a trauma unit (Lewis and Knottenbelt 1991). Penetrating trauma may be truly uncontrolled or accidental in nature; however, identical complications and injuries are seen after the intentional controlled trauma of surgery. This chapter will therefore deal with the complications of both salivary gland surgery and true traumatic injury. In addition, the injurious effects of radiation and barotrauma will be reviewed.

Penetrating Injuries

TRAUMA TO THE GLAND

Salivary Fistula

Penetrating injury to the substance of a major gland—for example, the parotid or submandibular

gland—will cause direct damage to the gland and possible related structures and may lead to the formation of an external salivary fistula to the skin (Figure 12.1). When the substance of the gland is injured, suture of the parenchyma is recommended (Lewkowicz, Hasson, and Nablieli 2002). In addition to direct closure of the parotid capsule, a pressure dressing for 48 hours is applied to reduce the chances of sialocele formation. In 51 cases of parotid complications following trauma, 15 (29.4%) developed parotid fistula, treated by intravenous fluids and nil by mouth, with faster healing of parenchymal injuries alone than when the ductal system was involved (Parkeh, Glezerson, and Stewart et al. 1989). Similarly, Ananthakrishnan and Parkash (1982) reported that their 3 cases of fistula from the parotid gland parenchyma resolved without treatment, unlike the 14 fistulae related to parotid ductal injury. In a study of 13 patients with traumatic parotid fistulae, 54% resolved with conservative management within 3 weeks and the remainder were cured by internal drainage with a catheter (Cant and Campbell 1991). Landau and Stewart (1985) advocated conservative management of post-traumatic parotid fistulae and sialoceles and found that parenchymal injuries alone resolved in 5 days, whereas ductal injuries took 14 days. Morestin (1917), in a series of 62 war injuries with parotid fistula, 30 glandular and 32 ductal, reported good success with the creation of an intraoral fistula. In more extensive avulsive injuries with gross scarring, conservative treatment may be less successful (Figure 12.2), and established epithelialized fistulae require excision with repair of the parotid capsule and closure.

The submandibular gland is less liable to be involved in the development of traumatic fistulae, perhaps because it is protected by the mandible and its smaller size. Few cases of submandibular gland fistulae have been reported. A case report of submandibular gland fistula secondary to a gunshot wound was reported in 1995, where the authors also reviewed the literature and found only one

Figure 12.1b. Exploration via a modified Blair incision to check for damage to the external carotid artery and facial nerve and to suture the parotid capsule.

other case from 1976 (Singh and Shaha 1995). In their 1995 case the fistula resolved without active treatment in 10 days.

Rarely internal parotid fistulae can occur presenting as rhinorrhea or rhinorrhea related to food,

usually as a result of maxillary fracture with parotid fistula into the maxillary antrum (Faussat, Ghiassi, and Princ 1993; Scher and Poe 1988). In a recent report of parotid fistula into the maxillary antrum (and a very rare case of a sublingual gland fistula to the skin), excellent results were achieved with botulinum toxin injection (Breuer, Ferrazzini, and Grossenberger 2006). Although the authors state that primary surgical repair should be carefully considered, they found the injection of botulinum toxin to be effective, to shorten fistula closure time, and to be minimally invasive. The current management of fistulae from the parotid gland parenchyma is therefore conservative, as cases that do not involve the duct will resolve. In recalcitrant cases botulinum toxin appears a good option. True fistula post-surgery—for example, superficial parotidectomy—is not common but may occur through the surgical skin incision. Usually management with antisialogogues, nil by mouth, or botulinum toxin will lead to resolution. In a report of 3 cases post-parotidectomy treated with injection of botulinum toxin under electromyographic control, all resolved with no recurrence 14–21 months after therapy (MarcheseRagona et al. 2006).

Sialocele

A sialocele is formed by the extravasation of saliva into glandular or periglandular tissues due to disruption of the parenchymal or ductal structures of the salivary gland. This is most commonly seen following trauma, and the usual sites are the sublingual gland (ranula) or minor salivary glands (mucocele). Ranulae and mucoceles were discussed in chapter 4, and this section will concentrate largely on parotid sialoceles. Parotid sialoceles are usually seen after penetrating trauma to the parotid region and will present as painless, cystic swellings that are gradually increasing in size. Aspiration of the sialocele with fluid positive for amylase >10,000 units/liter will confirm the diagnosis. Computerized tomograms will show a cystic mass with smooth margins and a density lower than the surrounding tissues. After 2 weeks there will be enhancing borders due to the development of a capsule (Cholankeril and Scioscia 1993) (Figure 12.3).

Traditional management has been conservative, the same as for parotid parenchymal fistulae (Cant and Campbell 1991; Landau and Stewart 1985; Parkeh, Glezerson, and Stewart et al. 1989), with resolution reported in approximately the same time period as for fistulae. Most sialoceles develop 8–14 days post-injury, and the development of a late capsulated sialocele is more difficult to treat. Literature reviews show that treatments proposed include multiple aspirations, pressure dressings, secondary duct repair if this is the etiology, creation of an intraoral fistula, sectioning the auriculotemporal nerve, the use of antisialogogues (atropine, probanthine, glycopyrolate), duct ligation, and even radiation or parotidectomy (Canosa and Cohen 1999; Lewkowicz, Hasson, and Nablieli 2002) (Figures 12.4 and 12.5).

In recent years the use of botulinum toxin has caused a paradigm shift in the way these injuries can be managed. In 1999 Ragona, Blotta, and Pastore et al. reported a case of post-traumatic parotid sialocele resistant to conservative therapy that was successfully cured using botulinum injection. These authors used botulinum F due to its earlier and shorter efficacy compared to botulinum A, and injected the gland with electromyographic control. Botulinum toxin works by causing a chemical denervation of the gland by blocking the cholinergic neurotransmitter. Following this paper a

a

b

Figures 12.3a and 12.3b. Frontal and three-quarter views of patient with right parotid sialocele post-surgery.

report of 4 cases of recurrent post-parotidectomy sialoceles treated with botulinum A toxin injected subcutaneously with 100% success was published (Vargas, Galati, and Parnes 2000), as well as other

Figure 12.4a. A 41-year-old male post-gunshot wound that entered in the left parotid region and traversed to the right parotid region with fracture of both left and right condyles. He developed an increasing sialocele in the right parotid gland.

Figure 12.4b. Panoramic film shows the retained bullet in the right parotid gland (arrow).

Figure 12.4c. Modified Blair incision and partial parotidectomy, with mosquito forceps indicating the bullet. The bullet was situated between the superior and inferior branches of the facial nerve, which was intact with no weakness. The capsule of the parotid gland was repaired and the sialocele resolved. Reprinted with permission from Blanchaert R, Ord RA. 1997. Management of late complications of penetrating injuries to the parotid gland. Pan American Journal of Trauma 6(1):52–57.

Figure 12.5a. Plain film of a 20-year-old man following a gunshot wound shows the bullet “floating” in parotid sialocele.

Figure 12.5b. Surgical exploration to remove the bullet revealed an abscess cavity where the bullet had lodged. Note draining pus. Reprinted with permission from Blanchaert R, Ord RA. 1997. Management of late complications of penetrating injuries to the parotid gland. Pan American Journal of Trauma 6(1):52–57.

case reports (Chow and Kwok 2003). There is a single case of a submandibular sialocele treated with resolution using botulinum toxin A (Capaccio, Cuccarini, and Benicchio et al. 2006).

Nerve Injury

The facial nerve is at risk from penetrating injury to the facial region both in the parotid and in the distribution of its peripheral branches to the facial musculature. It is stated that damage to branches distal to a line drawn from the lateral canthus to the commissure does not require repair and may be managed expectantly. All patients with facial wounds should have a careful clinical examination of facial nerve function. Where this is not possible—for example, in the unconscious patient or the uncooperative infant (Figure 12.6)—the wound should be carefully explored at the time of surgery to exclude transaction of the branches of

Figure 12.6. Infant with laceration from broken glass. No facial nerve damage was present.

294 Trauma and Injuries to the Salivary Glands

the facial nerve. Primary repair soon after the injury with end to end anastomosis is the ideal scenario, as paralysis of the facial nerve is a devastating injury for the patient, and even when “successful” nerve repair has been carried out with satisfying results (based on House-Brackmann, Stennert, and May grading), patients experience a reduced quality of life (Guntinas-Lichius, Straesser, and Streppel 2007) (Figures 12.7 and 12.8). This section will discuss the management of the primary nerve injury and will not discuss the techniques for facial reanimation or static slings, which are beyond the scope of this text. The interested reader will find many recent review articles addressing these topics (Guntinas-Lichius, Streppel, and Stennert 2006; Malik, Kelly, and Ahmed et al. 2005).

Classically the nerve is sutured under the microscope using 9-0 or 10-0 nylon sutures attempting to coapt the nerve ends without tension (Figure

12.9). The suturing can be epineural or fasicular. In epineural suture less damage is caused to the neural bundles with less foreign body reaction in the fasicles due to the suture materials; however, fasicular suturing should allow better adaptation of the fasicles and trimming back the epineurium to prevent fibrous tissue in-growth. However, anatomic studies have shown the fasicular and connective tissue anatomy of the facial nerve to be complex, with the number of fasicles increasing in a proximo-distal way from the geniculate ganglion