The Bipolar Coagulation Forceps Prevented Salivary Fistula in Patients with Parotidectomy

Background: Salivary stula is a relatively common complication in patients with parotidectomy. The purpose of this study was to investigate the effect of bipolar coagulation forceps in salivary stulas. Method and Material: From March 2015 to June 2020, 177 patients for management of parotidectomy were recruit from the Department of Oral and Maxillofacial Surgery at the Second Xiangya Hospital, Central South University. The patients were divided into experimental group and control group according to application of bipolar coagulation forceps or suture, respectively. Results: The draining output of experimental group was dramatically decreased compared to control group (p = 0.04). The duration of pressure dressing application in experimental group was signicantly increased compared to control group (p = 0.0003). Moreover, the incidence of salivary stula in experimental group (9.8%, 8/82) was notably lower than that in control group (34.7%, 33/95) (p < 0.0001). In logistic regression model for salivary stula development, both of bipolar coagulation forceps (p = 0.0026) and draining output (p = 0.0186) associated with salivary stula. Conclusion: Our ndings indicated that bipolar coagulation forceps decreased the incidence of salivary stula in parotidectomy patients. The bipolar coagulation forceps is a safe, effective, and convenient method to prevent salivary stulas in parotidectomy patients.


Introduction
Salivary gland tumor is relatively rare and constitute approximately 3-4% of head and neck tumors [1].
Moreover, parotid tumor is the most common salivary gland tumors, accounting for 80% of salivary gland neoplasms [2]. Although the most tumors in minor salivary gland are malignant, the majority tumors in parotid tumors are benign [1]. Parotid neoplasms vary widely in pathological diagnoses [3], while the complications present usually similarly due to common anatomic location. The surgical treatment is still a universally accepted therapy for benign parotid neoplasms. The parotidectomy inevitably destroy the entirety of parotid lead to various complications including facial nerve paralysis, salivary stula and Frey's syndrome.
Salivary stula is a relatively common complication that occurs between 5-39% [4], decreasing the quality of life in patients with parotidectomy. This complication also could cause visible scarring and wound infection. To meet this challenge, a continuing pressure dressing for the parotid region is necessary, which lead to esthetic morbidity, prolonged hospitalization, increased costs, and emotional instability [5]. Thus, it is important to identify a novel treatment that decrease the occurrence of salivary stula.
In preset study, we aimed to investigate the effect of bipolar coagulation forceps in salivary stulas. This study revealed that bipolar coagulation forceps can be applied in parotidectomy to reduce the incidence of salivary stulas.

Method And Material
Patients and study design The present study was a retrospective cohort study. From March 2015 to June 2020, 177 patients for management of parotidectomy were recruit from the Department of Oral and Maxillofacial Surgery at the Second Xiangya Hospital, Central South University. The study was approved by the institutional review board of the Second Xiangya Hospital and informed consent was obtained from all participants. The patients with parotidectomy history were excluded. The surgical procedures were performed by senior surgeons. The surgical procedures include tumor and partial super cial parotidectomy with branched facial nerve dissection, tumor and partial super cial parotidectomy with main trunk facial nerve dissection, tumor and total parotidectomy with main trunk facial nerve dissection. Then, the operative wound of parotidectomy were sealing by bipolar coagulation forceps (TIANEN TECHNLOGY Co., Ltd, China) or sutured, respectively. The patients were divided into experimental group and control group according to application of bipolar coagulation forceps ( Fig. 1) or suture, respectively. Finally, negative pressure drainage devices were used to collect postoperative secretion. The restraining bandage was used for maintaining a continuing pressure to operative region, postoperatively. The 24 h drainage were recorded for each day until the negative pressure drainage was uprooted with the criterion that the drainage was < 10 mL for two consecutive days or after 8 days [3]. All patients underwent routine observation and strict follow-up. Salivary stula was de ned when an effusion developed in surgical region after removing drainage device. The clinical parameters of patients were obtained from medical record. The tumor volume was measured using the following formula: tumor volume = 0.5 × length × width 2 .

Statistical analysis
Data were analyzed using SPSS 17.0 (SPSS, Chicago, IL, USA). The signi cance of differences between groups were performed with the chi squared, t test, Fisher's exact test or the nonparametric Mann-Whitney U test depending on the type of data and distribution. Logistic regression analysis was performed with salivary stula. All values were two sided, and p < 0.05 was considered to be signi cant.
The clinical parameter was recorded in Table 1, and there were no signi cant differences between experimental and control group. The postoperative characteristics was showed in Table 2. The draining output of experimental group was dramatically decreased compared to control group (p = 0.04). The duration of pressure dressing application in experimental group was signi cantly increased compared to control group (p = 0.0003). Moreover, the incidence of salivary stula in experimental group (9.8%, 8/82) was notably lower than that in control group (34.7%, 33/95) (p < 0.0001). In logistic regression model for salivary stula development, both of bipolar coagulation forceps (p = 0.0026) and draining output (p = 0.0186) associated with salivary stula.

Discussion
Salivary stula is a relatively common complication in patients treated with parotidectomy. Salivary stulas could persist for a long period after complete wound healing, which may lead to visible scarring and wound infection. To meet this challenge, we aimed to investigate the effect of bipolar coagulation forceps in salivary stulas. In this study, the results suggested that the parotidectomy patients treated with bipolar coagulation forceps had a lower incidence of salivary stulas.
The disease management always consist of diagnosis and therapy. The recent study suggested that drain uid amylase could serve as a predictor for postoperative salivary stula in benign parotid tumors [3]. The parotid capsule's persistence was correlated with salivary stula [3], while closure of the parotid capsule had no effect on deceasing of salivary stula postoperatively [6]. The results indicated that the size of parotidectomy wound area determined occurrence of salivary stula postoperatively. For decreasing salivary stula incidence, the previous studies reported many therapeutic techniques including reduction in oral intake and parenteral feeding [7], sewn site of the salivary leak [6], application of restranining bandage [3], use of anticholinergic agents [8,9], injection of botulinum toxin [10][11][12], application of cyanoacrylates after closing skin incision [13], the resection of tympanic nerve [14], and management of radiation therapy [15]. In present study, our results showed that the application of bipolar coagulation forceps decreased the incidence of salivary stula in parotidectomy patients. It could serve as a novel treatment for salivary stula. As we expected, the patients in control group had more draining output than experimental group.
Electrosurgical instruments, producing heating, was used to control bleeding in surgical procedures [16].
Bipolar coagulation forceps always applied as hemostatic devices in operation [17,18]. In present study, we found that the patients treated with bipolar coagulation forceps had a lower incidence of salivary stula. Due to fragile characteristic of parotid gland, the parotid wound region, treated with surgical suture, easily developed to wound dehiscence postoperatively, caused salivary stula. However, the bipolar coagulation forceps could seal parotid wound region between the forceps, which facilitated the fresh gland wound healing. This may explain that the parotid wound treated surgical suture had a high incidence of salivary stula. The study of Zou showed that methylene was injected into Stensen's duct for ligating the broken duct [19], while the broken intercalated duct and secretory duct hardly had been ligated. The application of bipolar coagulation forceps could resolve the problem. The convenience is the most advantage of bipolar coagulation forceps with universal application for hemostasis.

Conclusion
In this study, we found that bipolar coagulation forceps decreased the incidence of salivary stula in parotidectomy patients. The bipolar coagulation forceps is a safe, effective, and convenient method to prevent salivary stulas in parotidectomy patients.
Declarations Acknowledgements Not applicable.
Authors' contributions KW wrote the paper. KW and YY carried out data collection. KZ and SL were involved in statistical analysis. SZ modi ed the paper and designed this study concepts. All authors read and approved the nal manuscript.

Funding
Not applicable.

Availability of data and materials
The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Ethics approval and consent to participate
The study was approved by the institutional review board of the Second Xiangya Hospital and informed consent was obtained from all participants.

Consent for publication
Not applicable. The data showed as mean ± SD; Surgical procedure, A: tumor and partial super cial parotidectomy with branched facial nerve dissection; B: tumor and partial super cial parotidectomy with main trunk facial nerve dissection; C: tumor and total parotidectomy with main trunk facial nerve dissection. The data showed as mean ± SD. Table 3. Logistical regression analyses of Salivary stula and clinical characteristics. CI, con dence interval; OR, odds ratio.