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B. Swendseid et al. / Oral Oncology 73 (2017) 43–47

Table 1 Preoperative and perioperative data. A majority of our patient cohort was female, and over half had a tissue diagnosis of malignancy before their planned surgery. Three quarters had normal facial nerve function preoperatively, and nearly one quarter had pain in the parotid region. Squamous cell carcinoma was the most common pathologic diagnosis, followed by primary parotid neoplasms. Half of our patients required resection of the deep parotid lobe. Some degree of nerve sacrifice was necessary in 40% of our patients, but total nerve sacrifice was performed in only 19%. Patient preoperative and perioperative data Values n (%) Mean (SD, range) Preoperative data Patients 75 Age (Years) 69.1 (15.3, 3–92) Sex (Female) 43 (57.3%) Smoking history 37 (49.3%) Presence of mass (Months) 8.5 (15.6) Range: 1–48 Preoperative tissue diagnosis of malignancy 48 (64.0%) Normal facial nerve function 56 (74.7%) Pain in parotid region 17 (22.6%)

with high grade requiring total sacrifice 46% of the time compared to 50% for low grade. In patients with normal preoperative nerve function and lack of parotid area pain, nerve sacrifice was still performed in 5 (10.9%) cases. We analyzed these cases in greater detail. One patient had a high grade Acinic cell carcinoma requiring sacrifice of isolated nerve branches during a superficial parotidectomy. The remaining 4 patients had metastatic skin cancers (3 squamous cell, 1 mela noma) requiring total parotidectomy. 2 of these patients were receiving surgery for recurrent disease, 1 of whom had was receiv ing a revision parotidectomy. Therefore, the 10.9% of patients requiring nerve sacrifice in the absence of pain or preoperative dysfunction had other worrisome clinical factors like more aggres sive tumor pathologies, more extensive surgical intervention (total parotidectomy) and recurrent disease. Length of presence of parotid mass, smoking or drinking history, metastatic vs. primary tumors, gender, and positive nodal status did not predict nerve sacrifice. The incidence of facial nerve sacrifice in the setting of parotid malignancies was previously unknown. Our results showed that in this population complete nerve preservation is possible in 80.4% of patients with normal preoperative facial nerve function, and 90.6% in patients without pain or weakness. Increasing utility of fine needle aspiration in salivary gland neoplasms combined with improvements in cytology and immunohistochemistry has given otolaryngologists the ability to have a preoperative diagnosis of malignancy before definitive surgery. While malignancy is known to be associated with nerve sacrifice, the head and neck sur geon lacks predictive tools for discussing the likelihood of this occurrence. In addition, while facial nerve dysfunction and pain would suggest involvement of the nerve, no studies have been published that provide exact rates for when this would occur, or the extent of nerve sacrifice that is likely to be performed. Table 2 Predictors of facial nerve sacrifice. On univariate analysis, patients were significantly more likely to require intraoperative facial nerve sacrifice if they presented with preoperative facial nerve weakness, pain in the parotid region or received resection of the deep lobe of the parotid gland. In terms of tumor pathology, metastatic melanoma significantly reduced the likelihood of nerve sacrifice, and squamous cell carcinoma approached but did not reach significance for increasing likelihood for nerve sacrifice. Predictors of facial nerve sacrifice FN Sacrifice FN Preservation P value Number of patients 30 45 – Pre-operative factors Age in years (SD) 72.1 (11.6) 67.1 (17.3) 0.17 Female 14 (34%) 27 (66%) 0.26 Normal pre-op FN function 11 (20%) 45 (80%) 0.0006 Presence of mass in years (SD) 1.05 (1.9) 0.56 (0.62) 0.11 Pre-op pain 13 (76%) 4 (24%) 0.001 Smoking history 16 (43%) 21 (57%) 0.57 Alcohol history 22 (42%) 30 (58%) 0.54 Operative factors Total parotidectomy 24 (65%) 13 (35%) 0.0001 Lymph node dissection 25 (45%) 31 (55%) 0.16 Pathology Primary parotid carcinoma 11 (42%) 15 (58%) 0.77 Melanoma 1 (8%) 11 (92%) 0.037 Squamous cell carcinoma 17 (52%) 16 (48%) 0.074 Other tumor characteristics High grade tumor 26 (46%) 31 (54%) 0.086 Low grade tumor 4 (22%) 14 (78%) 0.086 Positive lymph nodes 18 (49%) 19 (50%) 0.13 Presence of metastasis 13 (36%) 23 (64%) 0.51 Bold indicates statistical significance. Discussion

Perioperative data Tumor pathology Melanoma

12 (16.0%) 33 (44.0%) 25 (33.3%)

Squamous Cell Carcinoma

Primary parotid carcinoma (mucoepidermoid, adenoic cystic carcinoma, salivary duct adenocarcinoma, etc.)

Mucoepidermoid

7 2 8 3 5

Adenoic cystic carcinoma Salivary duct carcinoma Acinic cell carcinoma Other primary carcinoma

Basal cell carcinoma

4 (5.3%) 1 (1.3%)

Lymphoma

Tumor grade High grade tumor Low grade tumor

57 (76.0%) 18 (24.0%)

Operative management Superficial parotidectomy Total parotidectomy Lymph node dissection Facial nerve sacrifice

38 (50.7%) 37 (49.3%) 56 (74.7%) 30 (40.0%) 23 (30.7%) 24 (32.0%) 14 (18.7%)

Upper division Lower division

Total nerve sacrifice

nerve function could have their nerve preserved . As expected 100% of patients with abnormal facial nerve function required some degree of nerve sacrifice. Pain combined with preoperative malig nant diagnosis resulted in some degree of nerve sacrifice in 75% of patients, compared to 33.3% of those without pain. Overall, 89.1% of patients with normal pre-operative facial nerve function and without pain had total nerve preservation , while having one of these factors resulted in at least partial nerve sacrifice 81.8% of the time (Table 4). We also found that a diagnosis of melanoma was protective against the need for facial nerve sacrifice, with only 1 out of 12 patients requiring nerve sacrifice (9%). Squamous cell carcinoma was the most likely to require facial nerve sacrifice, with results trending towards statistical significance (p = 0.074). For primary parotid malignancies, 44% required some degree of sacrifice. How ever, if these patients had normal preoperative facial nerve func tion, the nerve could be preserved in its entirety 87.5% of the time. While adenoid cystic carcinoma (ACC) is known for its local aggressiveness and nerve invasion, we only had two such cases in our review. One required total nerve sacrifice and the entire nerve was preserved in the other. Overall, tumors classified as ‘high grade’ had a higher propensity to require nerve sacrifice compared to ‘low grade’ tumors (46% to 22%). The likelihood of requiring total nerve sacrifice rather than partial did not vary by tumor grade,