Evaluation of postoperative complications in elderly patients submitted to parotidectomy

Objective: to evaluate the most incident histological subtypes and the main postoperative complications in elderly patients with parotid tumors submitted to parotidectomy. Methods: we conducted a retrospective study with 57 elderly patients submitted to parotidectomy from 2003 to 2017, at the São José County Hospital of Joinville, Santa Catarina, Brazil. Results: thirty-three (57.9%) patients had benign tumors, the most frequent being Warthin's tumor, and 17 (29.8%), malignant tumors, squamous cell carcinoma being the most frequent. Seven patients (12.3%) presented clinical complications, arterial pressure instability and respiratory complications being the most frequent, in four (7%) and three (5.3%) cases, respectively. Thirteen (22.1%) patients presented complications related to the surgical wound, hematoma and wound infection being the most frequent, with six (10.5%) cases each. Twenty-four (42.1%) patients had some degree of facial nerve dysfunction in the postoperative period, Brackman-House grade III being the most frequent, in 11 cases (19.3%). Surgical time and lymphadenectomy were associated with clinical complications. The main variables that showed an association with surgical complications were tumor size, longer surgical time, reoperation, and perioperative crystalloid infusion volume. Conclusion: parotid neoplasms present a differentiated profile in the elderly population, especially Warthin's tumor and squamous cell carcinoma. Hematoma and infection of the operative wound and facial nerve lesions were the most prevalent complications in the postoperative period.


INTRODUCTION
A bout 80% to 85% of salivary gland tumors occur in the parotid, corresponding to approximately 3% to 7% of all head and neck neoplasms.About 25% of them are malignant 1 and surgery is the main form of treatment [1][2][3] .
The elderly population -aged 60 and overis growing and Brazil will be the sixth country with the largest elderly population in the world by 2025, according to the World Health Organization 4 .Thus, an increasing number of elderly people will need surgical treatment, with a direct impact on the health system expenses.Old age has physiological peculiarities that, associated with comorbidities, represent a challenge for surgical decision-making, as well as for postoperative management.
The objective of this study was to evaluate the histological subtypes of parotid tumors most incident in this age group, as well as the main complications in the postoperative period in elderly patients submitted to parotidectomy.

RESULTS
In the period from 2003 to 2017, 194 parotidectomies were performed, of which 101 in patients younger than 60 years.We excluded 30 patients due to incomplete information in their medical records.Thus, we studied 57 patients, of whom 38 (66.7%) were male (2:1 male:female ratio).The mean age was 67.53±6.57years (60 to 85 years).Of the 57 patients, 34 (59.65%) had a history of smoking, and the main comorbidities were systemic arterial hypertension (SAH) in 27 (47.37%)and diabetes mellitus (DM) in ten (17.54%).Seven (12.28%) patients had a history of neoplasms.The majority (84.2%) were classified as ASA II (American Society of Anesthesiologists) in the preanesthetic evaluation (Table 1).
Ultrasonography was the most performed exam and the mean lesion size was 2.95±1.11cm.FNA showed a sensitivity of 50%, specificity of 100%, Positive Predictive Value (PPV) of 100% and Negative Predictive Value (NPV) of 83.33% in relation to the diagnosis of malignant neoplasias (Table 1).
Thirty-three (57.9%) patients had benign tumors, the most frequent being Warthin's tumor in 20 (35.1%), followed by pleomorphic adenoma in 12 (21%) and myoepithelioma in one (1.8%).Seventeen (29.8%) were malignant tumors, squamous cell carcinoma being the most frequent, with eight (14%) cases, followed by pleomorphic exadenoma carcinoma, with two (3.5%), and salivary duct carcinoma, with two (3.5%) cases.There was an increased incidence of malignant tumors with increasing age, the incidences of benign and malignant tumors becoming similar over 70 years, as shown in figure 1.The mean size of the surgical specimen was 5.92±1.85cm(Table 3).

DISCUSSION
Neoplasms of the parotid glands affect 1:100,000 inhabitants, representing 0.6% of all neoplasms 1,3,5,6 .Among the benign ones, the pleomorphic adenoma is the most common type, followed by the Warthin's tumor 1,3,7,8 .Malignant tumors are a minority, occurring in 15% to 30% of cases, and among these, the most common primary neoplasias are mucoepidermoid carcinomas followed by adenoidecystic carcinomas 3,7,8 .However, the incidence of parotid tumors is influenced by geography, gender and age 3,7 .The frequency of malignant tumors of the parotid glands also varies possibly due to the lower incidence.In Brazil, a review of 154 cases showed a predominance of pleomorphic adenoma, followed by Warthin's tumor between benign neoplasms and mucoepidermoid carcinoma followed by squamous cell carcinoma among malignancies 6 .
In our study, there was a predominance of benign tumors, the most frequent being Warthin's tumor, followed by pleomorphic adenoma and myoepithelioma.This result corroborates with studies in the elderly populations 3,9 , in which the most common benign tumor was the Warthin's tumor and not the pleomorphic adenoma that leads the rates in the general population.Among malignant tumors, squamous cell carcinoma was the most frequent, contrasting with the worldwide incidence of malignant tumors of the parotid, so that only one patient had mucoepidermoid carcinoma and there were no cases of adenoidecystic carcinoma.
Other studies have shown a predominance of squamous cell carcinoma as the main malignant neoplasm in this age group 1,8 .Our study also showed that in the elderly, the male gender is more susceptible to parotid neoplasias, in the proportion of 2:1, which has already been observed by other authors 1,7,8,10 .
FNA is an important diagnostic tool for lesions of the parotid gland, with the main objective of establishing the differential diagnosis between benign and malignant lesions 3,11 .Values of sensitivity and specificity vary greatly between studies.Values of 62% to 79% sensitivity and 98 to 100% specificity for diagnosis of malignant tumors were reported in studies with 153 and 320 patients, respectively 5,12 .In our study, 24.6% of FNA were indeterminate and one possible explanation is the delay in analyzing the slide by the pathologist.Deneuve et al. observed no cases of inconclusive cytological analysis when the specimen was analyzed by the pathologist immediately after collection and the puncture repeated in case of unsatisfactory material 13 .
Diagnostic tests for malignant tumor detection in our study were similar to other studies, with a low sensitivity (50%) and specificity of 100%.The low sensitivity may be a reflection of the sample size 3 .There were three cases of false negative for malignancy, in which cytology showed two cases of "epithelial proliferation" and one "suggestive of pleomorphic adenoma", whose histopathological reports were, in two cases, metastatic squamous cell carcinoma and one of ex-pleomorphic adenoma salivary duct carcinoma.
These results may have occurred due to sampling errors, lack of adequate material or difficulty distinguishing reactive cells from malignant ones 3 .Thus, our findings show that cytological results compatible with benign lesions should not be used to guide an expectant management in tumors of the parotid glands 13 .
There is strong evidence that 60% of parotid tumors are in close contact with the facial nerve and that the risk of nerve damage is proportional to the extent of neural dissection 11 .
Thus, the main postoperative complication in parotid lesions is facial nerve dysfunction 3 .The incidence of neural dysfunction in our work reached 42.1%, with a predominance of grade III in 19.3% of cases, similar to that described in the literature, in which rates range from 15% to 40%.Although our work evaluates the dysfunction only in the period of hospitalization after surgery, the literature shows that the vast majority of dysfunctions are transitory in the dissections of benign tumors and the risk of permanent injury occurs in 0% to 4% of the cases 11,14 .More conservative surgical techniques, which do not dissect all branches of the facial nerve and resect less parotid tissue, such as partial superficial parotidectomy, have become more popular 11,15 .In this context, studies showed a reduction in surgical time, lower rates of facial nerve dysfunction and better aesthetic results with partial parotidectomy in relation to superficial parotidectomy 11,15 .Our study demonstrated a tendency (without significance) to increase in cases of nerve dysfunction with superficial parotidectomy and a strong association of this complication with total parotidectomy.In a review of 131 patients, total parotidectomy was associated with a high incidence of neural dysfunction, with a 61% incidence in the postoperative period 16 .A higher incidence of facial nerve palsy is expected in radical surgical approaches, such as total parotidectomy 3 .
Among the procedures combined with parotidectomy, only lymphadenectomy showed association with facial nerve dysfunction.The literature shows that 14% to 24% of patients with parotid gland carcinoma will require cervical dissection due to clinical evidence of metastasis at disease presentation 17 .Thus, almost half of the patients submitted to lymphadenectomy presented infiltration of the facial nerve, most of whom had a diagnosis of invasive or metastatic squamous cell carcinoma (SCC).Thus, the risk and nature of the complications after parotidectomy depend on the extent of surgery, tumor pathology and tumor location within the gland 17,18 .In the intraoperative period, the volume of infused crystalloid and the surgical time showed an association with surgical wound complications.The volume infused causes tissue edema, leading to increased drainage through the wound in addition to hemodiluting factors of the coagulation cascade and healing.Edema, increased drainage and delay in wound drying are risk factors for infection [20][21][22] .It is consensual that the time of surgery predisposes to clinical and surgical complications, especially the increase in the incidence of infection.Shkedy et al. 22 found an association between a period longer than 120 minutes and operative wound infection.Infection is the most frequent complication in the literature, with incidence reaching 29.9% for salivary gland surgery 19,23,24 .Nouraei et al. demonstrated an incidence of 7% and identified age above 60 years as a risk factor for surgical wound infection 25 .
Edema and hematoma were reported as factors related to wound infection 22 .
Bleeding and hematoma after parotidectomy are uncommon and are usually related to inadequate hemostasis at the time of the surgical procedure.Treatment consists of evacuation of the hematoma and control of bleeding sites 26 .In an extensive review of 3,200 cases of head and neck surgery, parotidectomy was the procedure with the highest incidence of wound bleeding, 1.7% 27 .The incidence in our work was 10.5%, and four patients required a surgical reassessment to review hemostasis.
Despite the limitations of the study, related to the small sample and retrospective analysis, we conclude that the incidence of malignant tumors increases with age and are more common in the male gender.The benign and malignant histological subtypes present a differentiated profile in the elderly population in comparison with the general population, especially Warthin's tumor and SCC.The greater the age and the more aggressive the neoplasia, the greater the clinical and surgical complications, and the longer the hospital stay.
We conducted a retrospective cohort study of analysis of medical records of all patients aged 60 years or older submitted to parotidectomy from 2003 to 2017.We excluded patients with incomplete medical records from the study.The type of surgery performed was chosen based on the preoperative diagnosis, clinical presentation of the tumor, fine needle aspiration (FNA) and radiological examinations.All patients had the cervicomastoideofacial incision as standard Original Article Evaluation of postoperative complications in elderly patients submitted to parotidectomy.Avaliação das complicações pós-operatórias em pacientes idosos submetidos à parotidectomia.surgical access.Parotidectomy was classified as partial, superficial or total, based on the resected lobe and the extent of facial nerve dissection.Partial parotidectomy, considered as any procedure less extensive than superficial parotidectomy, does not imply dissection of the facial nerve.Superficial parotidectomy involves resection of the entire superficial lobe and dissection of all branches of the facial nerve.Total parotidectomy involves dissection of the entire facial nerve, with total removal of the parotid tissue from both the deep and the superficial lobe.In malignant tumors, cervical exploration for lymphadenectomy was performed in cases where there was lymph node enlargement in the preoperative evaluation, in those with positive FNA or with imaging tests suggestive of lymphadenomegaly.The surgical sites were drained and maintained with aspiration.All cases had histopathological confirmation.The risk of complication due to facial nerve palsy was assessed by the House-Brackmann scale.We evaluated clinical and surgical complications in the immediate postoperative period.We used the Chi-square test of independence for the associations between characteristics and outcomes.We used the Mann-Whitney test to compare the groups in relation to quantitative (numerical) variables.The level of significance was <0.05.We performed data analysis using the Microsoft Excel 2016 software and the EpiInfo software version 7. The study complied with the Code of Ethics of the World Medical Association (Declaration of Helsinki) and was approved by the Ethics in Research Committee of the São José County Hospital of Joinville, Santa Catarina, Brazil, under the number 80719317.3.0000.5362.

Table 2 .
Details of the procedures and perioperative complications.
* SD, standard deviation.Figure 1.Distribution of benign and malignant tumors according to age group.

Table 3 .
Characteristics of surgical specimens and histopathology.

Table 4 .
Complications in the postoperative period.

Table 5 .
Association between preoperative and perioperative variables with clinical complications.
* DP, standard deviation; ** ASA, American Society of Anesthesiologists; a Chi-square test of independence and Mann-Whitney Test.