By
Gamal Saleh
General Surgery Department, Faculty of Medicine, Benha University, Egypt
Aim:
ABSTRACT
The current study aimed to evaluate the applicability of retrograde facial nerve dissection during superficial parotidectomy for benign parotid adenomas as regards surgical and functional outcomes.
Methods: The study included 13 patients assigned for superficial parotidectomy using retrograde approach, one of them was assigned to be conducted using anterograde approach but converted to retrograde due to difficulty to identify facial nerve trunk. All patients underwent full history taking, clinical examination and radiological evaluation.
Results: Thirteen patients; 9 males and 4 females with mean age of 33.9±9.6 years were enrolled in the study. All patients had smooth intraoperative course with mean operative time of 91±23.3; range: 60-145 minutes, mean intraoperative blood loss was 53±13.9 ml. Suction drains were removed after a mean duration of 36.5±15.2 hours and mean hospital stay was 44.3±18.5 hours. Two patients showed partial facial weakness with a frequency of
15.4%. Both cases received medical treatment and physiotherapy and the weakness resolved after one and 3 months, respectively.
Conclusion: It could be concluded that retrograde parotidectomy is a feasible, safe approach for facial nerve dissection with minimal reversible postoperative complications and it is recommended if difficulties were anticipated or encountered during standard parotidectomy.
Keywords: Parotidectomy, Retrograde, Facial nerve.

INTRODUCTION
Parotid neoplasms represent 3% of all head and neck tumors. About
85% of the parotid gland tissue is located lateral to the facial nerve, i.e. the superficial lobe. Tumors occur equally in the tissue of both lobes so most of the tumors are superficial to the facial nerve (1) . The majority of parotid masses are benign pleomorphic adenomas that rarely recur, leaving a large group of patients healthy after their parotid surgery, with some desiring aesthetic improvement in their facial appearance (2) .
Surgery is the treatment of choice, with options ranging from simple enucleation to radical parotidectomy. Total or superficial parotidectomies are thought to be unnecessary for preventing recurrence in the majority of cases depending on the histology or location of the tumor, (3) . Therefore, partial superficial parotidectomy is now the treatment of choice in most cases of benign parotid tumors, since it allows complete excision of the tumor with sparing of the facial nerve. A radical procedure is, however, needed if malignancy is confirmed at frozen section (4) .
Zhou et al., (5) evaluated 62 cases of parotid pleomorphic adenoma; there have been no recurrence in all
44 patients operated by superficial parotidectomy, in all 16 patients operated by partial superficial parotidectomy plus partial deep parotidectomy, and in all 2 cases operated by total parotidectomy.
Two cases (4.5%) treated by superficial parotidectomy had transient facial nerve dysfunction, while none of the 16 cases treated by partial superficial plus partial deep parotidectomy had facial nerve dysfunction. Frey syndrome occurred in 8 cases (18%) treated by superficial parotidectomy, in 2 cases
(13%) treated by partial superficial plus partial deep parotidectomy and in all 2 cases (13%) treated by total parotidectomy with a total rate of
Frey syndrome of 19.3%.
Gaillard et al., (6) analyzed the incidence and factors associated with facial nerve dysfunction after conservative superficial parotidectomy with facial nerve dissection and found the incidence of postoperative facial nerve dysfunction was 42.7% on the first postoperative day, 30.7% at 1 month after the parotidectomy, and 0% at 6 months after the parotidectomy. The most common dysfunction was paresis in a single nerve branch
(48.2%), in particular, the marginal mandibular branch and inflammatory conditions were found as factors that increased postoperative dysfunction. facial nerve

Cannon et al., (7) tried to determine the relationship between the length of the facial nerve dissected during parotidectomy and subsequent facial nerve paresis and found that the main trunk of the facial nerve is located 1 cm from the tragal pointer and may need to be modified to less than 1 cm. The cervical and marginal mandibular branches had more nerve dissected, whereas the eye and forehead branches were the least dissected. Facial nerve paresis after parotidectomy is associated with the length of the facial nerve dissected during the procedure. The greater the length of facial nerve dissected, the higher the chance of facial nerve paresis, albeit temporarily.
There are two basic approaches for the identification and dissection of the facial nerve. One is the forward or anterograde dissection, where the approach to the main trunk is taken as an early step, tracing it to the bifurcation and peripheral branches.
The other technique is the retrograde dissection, where the peripheral branches are identified first, then proximally to the bifurcation or main trunk (8) .
The current study was designed to evaluate the applicability of retrograde facial nerve dissection during superficial parotidectomy for benign parotid adenomas as regards surgical and functional outcomes
PATIENTS & METHODS
This prospective study was conducted at Department of General
Surgery, Benha University Hospital since May 2008 till Jan 2011. After obtaining written fully informed patients' consent, 13 patients assigned for superficial parotidectomy using retrograde approach, one of them was assigned to be conducted using anterograde approach but converted to retrograde due to difficulty to identify facial nerve trunk. All patients underwent full history taking, clinical examination and radiological evaluation. Patients had benign tumors with no palpable lymph node or radiological evidence of spread was enrolled in the study. All excised specimen were sent for histopathological examination for assuring of being benign lesion.
Operative Technique
All surgeries were performed under general endotracheal anesthesia, patients received prophylactic antibiotic in the form of 3 rd generation cephalosporins. Patient's head was positioned to rest on a pillow on the healthy side and the external auditory meatus was

plugged and ear lobule was folded and retracted for complete exposure of the swelling.
A modified Blair incision, (Fig. 1) was used; the preauricular incision was made in the preauricular crease. The skin incision was deepened, and the skin flap was raised using subfascial dissection under the periparotid fascia, using cutting diathermy, (Fig. 2) to the superior, anterior and inferior borders of the gland with exposure the gland tissues and the zygomatic arch, (Fig. 3). No search was paid for frontal branch of the facial nerve as it was elevated with the superficial fascia. Temporal branch was identified in relation to the frontal branch of the superficial temporal artery, (Fig. 4). Blunt dissection with a haemostat was used while exposing the anterior border of the gland where the distal branches of the facial nerve emanate from the gland on to the masseter muscle. The great auricular nerve was identified and its posterior branch was preserved before the dissection of the facial nerve was commenced so as to diminish the loss of sensation to the earlobe.
Stensen’s duct was used as a landmark for the identification of the buccal and zygomatic branches of the facial nerve. The skin flap was pulled by a retractor to expose the protrusion of the anterior border of the gland, (Fig. 5) where Stensen’s duct emanates from the gland onto the masseter muscle, (Fig. 6). In 11 cases (84.6%) the facial nerve was found lying across the duct, and the duct was preserved during the dissection of the nerve; only in 2 cases the facial nerve was found lying posterior to the duct, so the duct was dissected, ligated and cut to allow exposure of the nerve branches, (Fig. 7). The duct was then traced towards the direction of the mouth in order to remove the remnants. Mandibular branch of the facial nerve was identified near the angle of the mandible and followed to its termination behind the mandible, (Fig. 8). Once a nerve branch was identified, dissection preceded using fine-tipped haemostats to create tunnels in the parotid tissue immediately above the nerve and the fine bridges of parotid tissue over-lying the nerve were preserved so as to avoid nerve injury. The dissection was conducted so as to displace the parotid upwards and downwards avoiding too deep and narrow tunnelling. As the bifurcation, (Fig.
9) and main trunk, (Fig. 10) of the facial nerve was exposed, the gland was resected at the posterior border.
The tumor was excised ‘en bloc’.
The wound is irrigated with saline and the integrity of the facial nerve

was checked, (Fig. 11). The superficial fascia was closed as a separate layer using vicryl 2/0 sutures. Closed suction drainage was used, the suction drain tube was inserted through a separate stab into the sub-facial space away from the dissected facial nerve to prevent damage to the nerve and wound was closed using subcuticular vicryl
4/0 suture, (Fig. 12). Closed suction drainage was maintained for 48 or
72 hours and, thereafter, a thin layer
. of gauze was placed on the wound.
The sutures were removed one week after operation.
The surgical feasibility, intraoperative bleeding, operative time and postoperative complication namely; occurrence of facial nerve weakness, hemoatoma or seroma formation, local saliva accumulation, or salivary fistula were evaluated as operative outcome
Fig. (1): Right parotid swelling, Blair incision marked
Fig. (2): Skin flap was dissected in subfacial plane using dissecting diathermy

Fig. (3): Parotid gland exposed and tail was dissected
Fig. (4): The temporal branch of facial nerve was dissected from gland tissue and elevated with skin flap
Fig. (5): Parotid duct emerging from the gland and facial nerve was identified crossing the duct
Fig. (6): Parotid duct completely dissected to the edge of the masseter muscle and was elevated
Fig. (7): Parotid duct was retracted and the buccal branch of facial nerve was dissected from gland tissue
Fig. (8): The mandibular branch of facial nerve was dissected from gland tissue

Fig. (9): The facial nerve bifurcation was dissected from gland tissue
Fig. (10): The facial nerve trunk was identified within gland tissue
Fig. (11): The facial nerve trunk and bifurcation were completely dissected and the gland was excised en bulk
Fig. (12): Wound was drained through a separate stab and was closed using subcuticular stitches
Fig. (13): Postoperative picture with patient blowing cheek normal bilaterality and forehead corrugations
Fig. (14): Postoperative picture with patient smiling normal angles of the mouth and both upper eyelids were on the same level

RESULTS
Thirteen patients; 9 males and 4 females with mean age of 33.9±9.6; range: 21-53 years were enrolled in the study. There was a nonsignificant difference between age of included patients categorized according to gender, (Table 1).
All patients had smooth intraoperative course with a mean operative time of 91±23.3; range: 60-
145 minutes. Intraoperative blood loss was minimal and ranged between 40 and 85 ml; mean=53±13.9 ml. Suction drains were removed after a mean duration of 36.5±15.2; range: 24-72 hours. Mean hospital stay was
44.3±18.5; range: 24-72 hours, (Table
2). Histopathological examination of excised specimens assured benign nature of the lesion that diagnosed histopathologically as pleomorphic adenoma of parotid.
During the immediate postoperative period only 2 patients (15.4%) showed partial facial weakness one showed signs of affection of the buccal and the other showed affection of the marginal mandibular branches of the facial nerve. Both cases received medical treatment and physiotherapy and responded to treatment and the weakness resolved one and 3 months, respectively, postoperatively. All other patients showed no objective or subjective evidence of facial weakness as judged by facial nerve integrity tests, (Fig. 13 & 14) and no salivary fistulae were reported in all cases.
Mild cheek edema was noticed and resolved on conservative treatment with anti-edematous drugs. No wound infection or hematoma collection was noticed. Throughout the postoperative follow-up no patient developed Frey' syndrome or complained of retromandibular recess.
Table (1): Patients' data
Number
Males Females
9 (60%) 4 (40%)
Total
13
Age
(years)
34±10
(21-53)
32.3±9.5
(26-46)
34±9.5
(21-53)
Data are presented as mean±SD & numbers; ranges & percentage are in parenthesis
Table (2): Operative and postoperative
data
Operative time
(minutes)
Intraoperative blood loss (ml)
Wound drainage period
(hours)
Hospital stay
(hours)
Mean±SD
91±23.3
53±13.9
36.5±15.2
44.3±18.6
Range
60-145
40-85
24-72
24-72

DISCUSSION
Despite the need for meticulous dissection for retrograde facial nerve identification with preserving function of each branch, mean operative time was 91±23.3; range:
60-145 minutes and mean intraoperative blood loss was
53±13.9; range: 40-85 ml, such figures go in hand with that previously reported in literature regarding retrograde parotidectomy. Bhattacharyya et al., (9) reported that compared to standard parotidectomy, retrograde parotidectomy consumed less operative time and resulted in decreased intraoperative blood loss (67.9 cc versus 40.3 ml).
As regards feasibility of the retrograde approach, no difficulty was encountered during identification or dissection of either the main trunk or the peripheral branches. In one case assigned for standard parotidectomy using anterograde approach, there was a difficulty for main trunk identification and more dissection appeared to be hazardous, a decision to shift to retrograde identification allowed easier identification of all the peripheral branches and dissection was easier and tracing them allowed identification of the bifurcation site and then the main trunk.
Postoperatively there was only transient affection of facial nerve function that resolved within one month of follow-up. Such case points to a fact that retrograde facial nerve identification and dissection was applicable for the difficult cases. Similarly; Pia et al., (8) reported 5 cases assigned for anterograde facial nerve identification that converted to retrograde, 3 cases on account of difficulty in locating the main trunk, due to the presence of a postinflammatory fibrosis and a stylomastoid emergency, arising from a malignant neo-formation in the other two.
Also, Mercante et al., (10) in their series of recurrent benign parotid neoplasia, the surgical technique used was retrograde dissection of the facial nerve starting from one of the peripheral branches and reported only a slight paralysis of some branches which recovered during the post-operative period.
For safety of individual facial nerve branches, the current study depended on identification of a prominent hallmark for each branch so as to undertake safe dissection;
Stensen’s duct was used as a landmark for identification of buccal and zygomatic branches of facial nerve and in 11 cases (84.6%) the facial nerve was found lying

across the duct, and the duct was preserved during the dissection of the nerve; only in 2 cases the facial nerve was found lying posterior to the duct, so the duct was dissected, ligated and cut to allow exposure of the nerve branches. Such strategy goes in hand with the results of multiple recent anatomical studies;
Saylam et al., (11) who reported that the buccal branches of the facial nerve are very vulnerable to surgical injury because of its location in the midface and for this reason, the surgeons who are willing to operate on this area should have a true knowledge about the anatomy of these branches. Erbil et al., (12) found the zygomatic branch of the facial nerve crossed the duct anteriorly in 90% of studied cases and in 10% it did so posteriorly and the intersection point of the zygomatic branch and the duct may be estimated to be within 5.16±1.01 cm of the lateral canthus. Liu et al., (13) , documented that parotid duct had a constant surface landmark with the buccal branch coursed within the distance between 10.7 mm above and 9.3 mm below the parotid duct.
Through the current study dissection and elevation of the skin flap was conducted at sub-fascial plane using cutting diathermy; such maneuver allowed easy dissection without missing of blood vessels or any of the parotid cutaneous ligament-like tissue projections that may obstacle for completion of dissection up to the zygomatic arch.
Moreover, such approach for skin flap dissection allowed preservation of the frontal branch of the facial nerve included in superficial fascia, identification of the zygomatic branch of the facial nerve at the zygomatic arch and the temporal branch of the facial nerve guided by pulsation of the superficial temporal artery. The applied approach agreed with Coscarella et al., (14) who reported that the frontal branch of the superficial temporal artery served as an important landmark for the subfascial dissections because excessive reflection of the scalp flap inferior to the level of this vessel would inadvertently injure the frontalis branch of the facial nerve. Also, Lei et al., (15) found the temporal branch locates within a triangular area formed by the lower aspect of the zygomatic arch, the frontal branch, and the vertical line where it crosses the highest point of the frontal eminence and concluded that the frontal branch of the superficial temporal artery can be the anatomical landmark used to locate and protect the temporal branch of facial nerve during face surgery.
Mandibular branch of the facial nerve was identified near the angle

of the mandible and followed to its termination behind the mandible.
Similarly, Liu et al., (13) reported anatomically that the marginal mandibular branch coursed within the distance between 13.4 mm above and 4.8 mm below the lower border of mandible, crossed superiorly the facial artery and concluded that there is a close relationship of marginal mandibular branch to facial artery and lower border of mandible.
Only 2 cases of partial nerve affection were reported postoperatively with a frequency of
15.4%. One showed a picture of buccal nerve affection with weak ability to distend the cheek and to blow air and the second showed minimal drop of the angle of the mouth due to affection of marginal mandibular branch of facial nerve.
Both cases received medical treatment and physiotherapy and responded to treatment and the weakness resolved one and 3 months, respectively, postoperatively. Such figures were in line with that reported by various studies concerning postoperative weakness of facial nerve after parotidectomy. Guntinas-Lichius et al., (16) , reported transient and permanent facial palsies with rates of 18% and 4%, respectively in their series of 260 patients. Marchesi et al., (17) reported temporary facial nerve paralysis in 10.3% of patients with a benign superficial neoplasm of the parotid treated by superficial parotidectomy. Upton et al., (18) reviewed a series of 237 patients who underwent parotidectomy and reported a frequency of postoperative facial nerve weakness of 18%.
Also, Heeremans & Mastboom, (19) evaluated the outcome of subtotal parotidectomy in 2 patients who even slight damage to the facial nerve during parotidectomy could have severe implications for their careers; postoperatively, there was clinically a temporary minor marginal branch dysfunction in one patient. Pre- and postoperative electromyography did not indicate asymmetrical function of the facial muscles. A few weeks after the operations, both musicians could resume work. O'Regan et al., (20) evaluated the facial nerve function in 136 patients who had had retrograde nerve dissection during parotidectomy for benign disease and reported that some weakness of the facial nerve was reported in 16% of studied patients and within 6 months 135 (99%) had normal nerve function, but one patient had persistent marginal mandibular nerve paresis. Similar results were obtained in the study of Anjum et al., (21) , who compared both retrograde & anterograde facial

nerve dissection techniques during superficial parotidectomy and reported no permanent facial nerve dysfunction in both groups.
It could be concluded that retrograde parotidectomy is a feasible, safe approach for facial nerve dissection with minimal reversible postoperative complications and it should be considered if difficulties were anticipated or encountered during standard parotidectomy.
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