INTRODUCTION

Traumas are the second most frequent causes of facial palsy, second only to the so-called idiopathic cases. Among the most common causes of trauma we can include head trauma, firearm wound, sharp wound to the face and iatrogenic damage at different regions of the nerve and in predicted and unpredicted situations.

Closed traumas of the head frequently cause fracture of petrous pyramid and facial palsy is present in about 40% of the transversal lesions and in 20% of the longitudinal ones 1. Longitudinal fractures are more frequent than transversal ones and normally produce clinical signs and symptoms that are less severe 2.

Firearm wounds of the temporal bone are also quite common in Brazil and they frequently cause otorrhea, deafness and facial palsy, in addition to endocranial complications 3.

Iatrogenic damage to facial nerve is the most feared complication of otological surgery. Most of the cases occur during mastoidectomy. Many factors may collaborate to such complication, such as advanced middle ear and mastoid disease, previous surgeries, abnormal pathway of facial nerve, and the surgeon's own lack of experience or skill.

The assessment of patients with traumatic facial palsy includes temporal bone imaging diagnosis, audiological testing, topographic tests and electrical prognosis 1, 4.

The treatment has been conservative for a long time, but surgical procedures have been described since the 10th century 5.

All cases of traumatic facial palsy should be submitted to surgical treatment when: 1) facial palsy is total or sudden; 2) electrical tests are non-excitable up to 5th day of palsy; 3) there is evident bone disjunction; 4) there is complete nerve section. Other authors also report that if there is no regeneration of palsy within 6 to 8 weeks, surgical exploration should be conducted 6-8.

OBJECTIVE

To study the incidence and progression of traumatic facial palsy.

MATERIAL AND METHOD

We conducted a retrospective study with 82 patients with traumatic facial palsy seen in the period between January 1990 and January 1999 in the ambulatory of facial nerve, Hospital São Paulo - UNIFESP. The ambulatory comprised a multidisciplinary team of physicians, one physical therapist and one speech therapist. There are about 150 new cases per year, and 6% of them are caused by trauma. All patients are assessed with physical examination, auditory tests, topographic location of lesion, prognostic tests and imaging tests. The levels were scored according to House-Brackmann classification9,10. In this group, 54 patients were male (65.8%) and 28 were female subjects (34.2%). Mean age was 30.9 years (ranging from 2 to 75 years). Racial distribution was 60 Caucasian (73.2%), 21 African-descendents (25.6%), and 1 Asian-descendent (1.2%). The distribution of sides was 40 cases of palsy on the right (48.7%), 36 on the left (43.9%) and 2 bilateral cases (2.4%). We studied the following variables: onset, type of trauma, initial electrical tests, initial grade and final grade using House-Brackmann classification9,10, type of treatment (clinical or surgical) and radiological and surgical findings in cases of head trauma.

RESULTS

Considering onset, there were 71 cases (86.5%) of sudden onset, 10 (12.3%) progressive cases and 1 (1.2%) case at birth.

As to trauma, there were 15 (18.22%) iatrogenic cases, 2 (2.44%) cases by sharp wound to the face, 50 (60.97%) cases after head trauma, 14 (17.07%) cases of firearm wound, and 1 (1.22%) case at birth.

As to initial electrical tests (conducted in 73 cases because the other 9 cases could not be assessed in the first days after onset of palsy) there were 32 (43.84%) patients with unexcitable tests, considering that among the 32 cases with symmetry we observed 24 cases of total recovery, 6 cases with 80% recovery, and 2 cases with 60% recovery; in unexcitable cases out of the 41 cases, only 5 progressed to total recovery.

Considering the initial palsy grade, we observed that in 31.70% of facial impairment there were 8 (9.75%) cases of grade II, 8 (9.75%) cases of grade III, 21 (25.60%) cases of grade IV, 32 (39.02%) cases of grade V, 13 (15.85%) cases of grade VI. In the cases of head trauma, we observed initial mean of 41.6% of facial function; in cases of iatrogenic lesions, 22.6%, in sharp wounds to the face, 10%; in cases of firearm wound, 11.4%, in cases caused at birth, 0%. As to final grade, the mean was 82.73% of facial function, divided into 30 (36.58%) cases of grade I, 28 (34.15%) cases of grade II, 21 (25.60%) cases of grade III, and 3 (3.65%) cases of grade IV. In cases of head trauma, the final mean was 90% facial function, in iatrogenic, it was 72%, in sharp wounds, 70%, in firearm wounds, 57.1% and in the subject affected at birth, 40%.

In regards to type of treatment, in the 50 cases of head trauma, 19 (38%) required surgical management (16 decompression and 3 graft procedures), and 31 (62%) of the cases did not require corrective surgery. In surgical cases, Computed tomography (CT scan) evidenced 13 longitudinal fractures, 3 transversal fractures and 3 cases without fractures. Surgical findings were: 11 edemas, 5 with bone fragments, and 3 with complete laceration of the nerve. Out of the 19 surgical cases, 5 progressed to G1 and 14 to G2 in House-Brackmann classification; in the 14 cases of firearm wound there were 8 (57.1%) grafts, 3 (21.5%) anastomoses, 2 (14.3%) decompressions, and only one case did not require surgery and presented spontaneous recovery. In the 15 iatrogenic cases, surgical approach was employed in 13 (86.66%) decompressions and 2 (13.34%) grafts; in 2 cases of sharp wound to the face, it was required to perform surgical exploration and anastomoses, and in the case caused at birth, only speech therapy and physical therapy were used.

DISCUSSION

There is much controversy concerning the need for surgery in managing facial nerve damage. However, in trauma cases, these questions are less frequently, especially in cases of sharp wound to the face, firearm wounds or iatrogenic lesions 11-13.

Many authors 1,2,6,7,8,11,12,15,16 reported that there is predominance of lesions in male subjects and in young adults that imply limitation of professional performance and cause severe changes to daily routine. In our sample we observed the same phenomena.

Most of the cases were unilateral, but there were two cases of head trauma with bilateral fracture and palsy that should be treated similarly to the other cases; for the surgical indication, we should favor the worse side or that with poorer hearing, as reported by other authors 2,6,8,11,14.

As to type of onset, most of the cases had sudden onset and this group gathered the most severe cases, of worse evolution and many required surgical treatment. This fact was equally observed by many other authors1,11,16.

It was not possible to define the time between diagnosis and treatment. The time it takes to start treatment normally worsens the prognosis. Bogar and Bento emphasized that it is important to interfere in cases of traumatic facial palsy even after months of onset, given that most of the patients experience improvement 17.

The most frequent cause of trauma was head trauma in which most of the subjects had mild manifestations, progressive cases of good evolution, who developed recovery without the need for surgery. Testa and Antunes found that the main cause of head trauma is car accident 18. Most of the cases of firearm wound, sharp wounds to the face, and iatrogenic causes required surgical approach, especially for the use of nervous grafts 1,8,11,13,16.

Electrical tests showed that in subjects with good prognosis the evolution is favorable, given that in most cases recovery is 80% to 100%. The test with Hilger stimulator proved to be reliable and safe as a screening method to analyze the prognosis of facial palsy evolution 4,14.

Electrical exams are essential in management and prognosis of the pathology. Electroneurography is the most reliable test because it provides percentage of lesion 19. If over 90% of the fibers are damaged, there is indication for surgical decompression. Electroneurography is valid up to 3 weeks; after this period, we should resort to electromyography.

CT scan in valuable in cases of traumatic palsy, but it is not essential as topodiagnosis or electrical tests are. We should bear in mind that if there is facial nerve trauma, if suffers retrograde degeneration of up to 5 mm.19

Brodie and Thompson, in 1997, in a retrospective study of 820 temporal bone fractures, concluded that the most important prognostic factors in recovery of facial nerve recovery were severity and time between palsy and trauma. In our study, we observed better prognosis in patients with incomplete palsy, with favorable electrical tests and in operated cases, and better recovery in patients submitted to total nerve decompression.

Based on the classification of House-Brackmann 9,10 we could classify the grades of initial and final impairment and check the progression of each type of trauma. In firearm wounds, we observed the worse initial indexes because of loss of nerve continuity and associated lesions. The best results were observed in cases of less severe head trauma.

CONCLUSION

In view of the results, we concluded that:

1. There was predominance of male subjects;

2. There was predominance of sudden cases and they progressed proportionally better than progressive cases;

3. There was predominance of cases of head trauma as etiology and they progressed proportionally better than other etiologies;

4. Electrical tests were able to predict quite well the progression of patients;

5. The type of management was proportionally more aggressive to the severity of the palsy and it produced good results;

6. In the studied surgical cases, there was predominance of longitudinal fracture and they led to the best results.

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