The key to proper management of parotid gland and duct injuries is early recognition at the time of primary assessment. Detailed history of the mechanism and timing of injury is required. Whenever an injury to the parotid gland or duct is suspected, the patient should be asked about the timing of the last meal since a recent meal will result in increased salivation with pouring of saliva into the wound [16]. On examination, an injury to the parotid gland or duct should be suspected whenever the wound affects the region extending from the tragus of the ear to the upper lip (imaginary line). When suspicious, massaging of the gland region can express saliva from the injured region. In many cases, cannulation of the parotid duct orifice with injection of saline and/or methylene blue (MB) is required to confirm or exclude parotid duct injury. Care should be taken not to stain the surrounding tissue when using MB, making detection of facial nerve injury and its repair troublesome.

Penetrating injuries to the parotid gland and duct region are usually associated with injuries to surrounding structures including:

Anastomosis is better done over a catheter introduced through the duct orifice. Injection of saline or MB facilitates recognition of the distal stump. The proximal stump is found through fine exploration of the wound. Massaging of the gland may aid the identification of the proximal stump through expression of saliva. At least 3 stitches with fine nylon sutures (9-0 or 10-0) are used to repair the duct. Alternatively, 7-0 or 8-0 silk sutures can be used. If a segment is lost, an autologous venous graft can be used for the repair [22]. Pressure dressing is required for 2 days, and the intraductal catheter should be left in place for 2 weeks postoperatively. Antisialogogues and antibiotics should be prescribed. Observation of the postoperative course is mandatory [18, 21].

In case of badly lacerated parotid duct, ligation of the proximal stump can be done aiming at atrophy of the parotid gland. This can be aided by the use of anticholinergic drugs. Alternatively, oral reimplantation of the proximal stump into the oral mucosa can be done [18].

Facial nerve integrity should be evaluated in any patient presenting with craniofacial injury through exclusion of motor facial deficits. If facial nerve affection is present, grading of the injury is essential as it can help in estimating the magnitude of the injury and the probable recovery potential. The “House-Brackmann” grading system is the most commonly used for this purpose [28]. A computed tomography can help in delineating the site of injury in cases of temporal bone fractures. Electroneurography aids in the identification of the degree of injury and in follow-up. Deteriorating results warrant nerve exploration [29].

For intratemporal injuries, a simple mastoidectomy is done for approaching the injured site. Only decompression is required if the nerve is not severed. If the nerve is severed, mobilization may be required to attain tension-free repair.

Injuries distal to the stylomastoid foramen should be suspected in any deeply seated wound along the course of the nerve as in case of deep cheek lacerations. A motor deficit should promote meticulous nerve exploration with the target being primary repair. The utilization of nerve monitor and surgical microscope is greatly helpful in this situation. It is well established that injuries distal to a line connecting the lateral canthus and gonial notch of the mandible do not require repair due to the distal branching of the facial nerve [18]. Otherwise, more proximal injuries require primary repair. Identification of the cut ends is the first concern, sometimes requiring a classic superficial parotidectomy to identify and trace the branches.

Crushed ends should be carefully trimmed and approximated without tension. Two or three nonabsorbable 8-0–10-0 monofilament sutures are placed through the epineurium with the help of surgical microscope (although several debates exist regarding the time and technique of repair). Mobilization may be required to attain such tension-free repair. If such approximation is not feasible, cable nerve grafting is done using either the great auricular nerve or sural nerve. Inferior to direct anastomosis and nerve grafting are the nerve substitution techniques involving either a hypoglossal-facial or a cross-facial anastomosis [30].

Recovery of motor functions usually requires at least 6 months following the injury. However, extent of recovery and the duration required vary widely according to the extent of nerve affection, site of trauma, and the methodology of the repair process. A certain degree of synkinesis almost always results.

In case of failure of primary treatment, a variety of secondary facial reanimation techniques exist with variable success rates. These techniques include the nerve substitution techniques, dynamic muscle slings, or static procedures [29].

Detailed history regarding the mechanism of trauma should be taken to assess the possible extent of injury. Any accompanying manifestations including loss of consciousness, dizziness, or headache should be noted and dealt with carefully as they may reflect concussions with associated intracranial injuries. It should be noted that almost half of the assault injuries to the MF region are associated with high alcohol levels, which can lead to a variable degree of confusion. This, however, should not be assumed as the causative factor until both intracranial injury and hypoxia are excluded [5].

Inspection of the nasal region can reveal variable degrees of external deformity, the detection of which can be facilitated by examination through the different views (frontal, worm’s eye, bird’s eye views) (Fig. 1.5). However, such deformity can be obscured by the resulting edema. Palpation may reveal nasal or septal deviations; a step deformity or crepitus can also be felt. Good lighting and proper nasal speculum are required to detect the integrity of septal cartilage and bone together with the development of septal hematoma. If the physician is familiar with fiberoptic naso-endoscopy, it will be a valuable tool to assess the nasopharyngeal cavity and the posterior nasal complex. Epistaxis and cerebrospinal fluid (CSF) rhinorrhea can be present; the latter should raise suspicion of an associated skull base injury. Thorough examination of the whole facial region is required to rule out associated MF injuries with special focus on the naso-orbital-ethmoid varieties [35].