Extracapsular Dissection Versus Partial Superficial Parotidectomy For The Treatment Of Benign Parotid Tumors

Objective: In recent years,the most common surgery performed has shifted from SP to PSP.Several studies have suggested that ECD may be a better choice for dealing with BPTs.The dissection of PSP includes the branches of the facial nerve,ligation of parotid duct,removal of partial superficial lobe of the parotid gland together with the tumor.PSP is considered to be safe and can minimize the rate of complications.However,ECD is the minimally invasive approach of parotidectomy,which removes tumors along with a 3-mm rim of healthy tissue surrounding the resection and less or without dissection of the facial nerve.Compared with PSP,ECD is less invasive and has lower complications rate.The recurrent rate does not increase.Based on above,the relative advantages of ECD and PSP remain controversial and there is no conclusion about which is better.So the purpose of this study was to compare the complications of patients treated for a benign parotid tumor(BPT)by extracapsular dissection(ECD)vs.partial superficial parotidectomy(PSP).We use systematic review and meta-analysis to collect relatively literature about postoperative outcomes of PSP and ECD,then analysis facial nerve injury,recurrence rate and other complications.We hope that it will provide a theoretical basis for the selection of the appropriate surgical approach in clinical.Methods: 1 Search Strategy The Pubmed and Cochrane Library databases were searched systematically,without restriction,for articles published before September 2018.Studies comparing ECD with PSP in patients with BPTs were retrieved with the following search terms: “extracapsular dissection,” “partial superficial parotidectomy,” “parotid resection,” “parotid tumors,” “parotid benign tumors,” and “parotid neoplasm.” The related-articles function was used to broaden the search.All of the retrieved abstracts,studies,and citations were reviewed,irrespective of publication language.2 Ducuments Screening Inclusion and exclusion criteria:(1)Studies comparing ECD vs.PSP in patients undergoing surgery for BPTs with an accurate description of the surgical technique and reporting at least one quantitative outcome measure were included.(2)The exclusion criteria were parotid malignancy,case reports/review articles,and lack of a stated follow-up period.3 Data Extraction Data were extracted independently by two investigators,and disagreement was resolved by discussion.For each study,the following information was extracted: first author,year of publication,study design,inclusion and exclusion criteria,number of patients who underwent each type of procedure,follow-up period,and outcomes.4 Statistical Analysis All analyses were performed with Review Manager,version 5.2,and STATA SE,version 12.0,software for Stata Corp.Odds ratios(ORs)were used to compare dichotomous variables.These were reported with 95% confidence intervals(CIs).An OR < 1 favored the ECD group.The point estimate of the OR was considered to be statistically significant at a p value < 0.05 if the 95% CI did not include the value 1.Results: 1 Literature search and study characteristics Briefly,electronic database searching identified 489 potentially relevant studies.After reviewing all of the abstracts,39 studies were deemed to be germane and suitable with respect to the inclusion and exclusion criteria.After reading the full-text articles,seven studies fulfilled the selection criteria and were included in this meta-analysis.The analyzed studies included 1,641 patients(1,120 subjected to ECD and 521 subjected to PSP).2 Facial nerve injury 2.1 ransient facial nerve injury The occurrence of transient facial nerve injury among 371 patients in four studies15-16,20-21 was lower for ECD than for PSP(OR = 0.28,95% CI: 0.11–0.71;p = 0.008;Fig.2A),with no significant between-study heterogeneity(χ2 = 0.80,df = 2,p = 0.670;I2 = 0%).2.2 permanent facial nerve injury The permanent facial nerve injury group included 1,411 patients from six studies15-16,18-21.Statistical analysis revealed no significant difference between ECD and PSP(OR = 0.77,95% CI: 0.35–1.70;p = 0.520;Fig.2B).In addition,no publication bias was detected(Begg’s test p = 0.373;Fig.3).3 Frey syndrome Analysis of data pooled from five analyzed studies15-16,19-21(398 patients)showed that patients who underwent PSP were more likely than those who underwent ECD to develop Frey syndrome(OR = 0.12,95% CI: 0.03–0.48;p = 0.003;Fig.4A).There was no significant between-study heterogeneity(χ2 = 3.07,df = 2,p = 0.220;I2 = 35%). 4 Recurrence Complete recurrence data were provided by two studies17,21,including a total of 277 patients.The recurrence rates were similar for the ECD and PSP patients(OR = 0.17,95% CI: 0.02–1.75;p = 0.14;Fig.4B).Due to the lack of significant between-study heterogeneity(χ2 = 0.39,df = 1,p = 0.53;I2 = 0%),a fixed-effects model was used.5 Infection Analyzable infection data were available from three studies16,20-21 involving a total of 256 patients.Pooling of the data showed that the postoperative infection rates did not differ significantly between the ECD and PSP groups(OR = 0.70,95% CI: 0.07–6.67;p = 0.76;Fig.4C).6 Salivary fistula or sialocele Analyzable salivary fistula/sialocele data were available from three studies16,20-21 involving a total of 256 patients.Pooling of the data revealed no significant difference between the ECD and PSP groups in terms of the rates of salivary fistula/sialocele(OR = 0.40,95% CI: 0.06–2.66;p = 0.350;Fig.4D).Conclusions: Although there was a trend that ECD showed a reduced risk for complications,the present results are not sufficient to conclude that ECD is more beneficial than PSP.Future well-designed,randomized clinical trials with a large number of patients and an extensive follow-up period are needed to confirm and update the findings of this analysis.