The Efficiacy of Sternocleidomastoid Muscle Flap on Frey's Syndrome via a Novel Test: Galvanic Skin Response

Meta-Analysis to Evaluate the Efficacy of Sternocleidomastoid Muscle Flap as a Reconstruction Modality in Prevention of Frey's Syndrome Following Parotidectomy

BACKGROUND

One of the commonest complications following parotidectomy is Frey's syndrome (FS). The use of sternocleidomastoid muscle (SCM) flap to prevent FS is controversial. Hence, this study has been designed to compare the effect of SCM flap with no reconstruction in prevention of FS following parotidectomy.

METHODOLOGY

An exhaustive literature search was conducted in July 2019. Studies focusing on sternocleidomastoid flap following parotidectomy were included in the meta-analysis. A random effects model was used to generate pooled estimates. Odds ratio with a 95% confidence interval was calculated for subjective symptoms and objective test.

RESULTS

A total of 125 studies were identified, out of which 17 studies were recruited in the meta-analysis. Sixteen studies were analyzed for the subjective symptoms, and ten were analyzed for the objective signs. There was no statistically significant difference in the occurrence of FS with the use of SCM flap on objective analysis. However, the subjective analysis showed a statistically significant reduction in FS following reconstruction with SCM flap after parotidectomy.

CONCLUSION

The present meta-analysis suggests that the use of SCM flap following parotidectomy has no effect in reducing the incidence of Frey's syndrome.

What is the best method for prevention of postparotidectomy Frey syndrome? Network meta-analysis

BACKGROUND

Prevention of Frey syndrome (FS) after parotidectomy using an interposition barrier has long been gaining a wide popularity; however, there is no clear evidence regarding which preventive technique is more effective. The aim of this network meta-analysis (NMA) is to answer the question: What is the best method for prevention of FS after parotidectomy?

METHODS

A comprehensive search of the PubMed, Embase, SCOPUS, and Cochrane library was conducted to identify the eligible studies. The outcome was the incidence of subjective Frey syndrome (SFS) and objective Frey syndrome (OFS). The Bayesian NMA accompanied with a random effects model and 95% credible intervals (CrIs) were calculated using GeMTC R package.

RESULTS

Thirty-four studies (n = 2987 patients) with five interventions, namely Alloderm (ADM), temporoparietal fascia (TPF), sternocleidomastoid muscle (SCM), superficial musculoaponeurotic system (SMAS), and free fat graft (FFG), were compared together and with no interposition barrier (NB). The results of NMA showed a statistically significant reduction in both SFS and OFS when ADM, TPF, SMAS, FFG, and SCM were compared with NB. No statistical differences were observed when comparing ADM, SCM, SMAS, FFG, and TPF. TPF ranked the best of all treatments (59.4%) and was associated with the least incidence of SFS; whereas ADM ranked the best of all treatments (61.1%) and was associated with the least incidence of OFS.

CONCLUSIONS

All interventions (TPF flap, ADM, FFG, SMAS, and SCM) were associated with a significant reduction in the incidence of FS when compared with NB. TPF and ADM showed the best outcome with the least incidence of SFS and OFS, respectively.

Use of the SMAS flap for reconstruction of the parotid lodge

The purpose of our study was to evaluate the benefits of the SMAS flap in patients with benign tumours of the parotid gland treated by superficial parotidectomy. We carried out a retrospective chart review on 123 patients suffering from benign tumours of the parotid gland admitted to our Institution between March 1997 and March 2010. A superficial parotidectomy was performed in all the cases reported. Our sample was divided in two groups basing SMAS flap reconstruction done (Group 2) or not (Group 1) after superficial parotidectomy. Reconstruction using SMAS flap was accomplished in 64 patients. Chi-square test was used to assess statistical difference between the two groups. The level of statistical significance was P < 0.05. No significant differences concerning hematoma, wound infection and facial paralysis were observed between the first and second group (3.38 vs 1.56% [P > 0.05], 8.47% vs 4.68% [P > 0.05], 5.08% vs 0.00% [P > 0.05]). Transient facial nerve weakness, fistula, dip skin and Frey's syndrome were significantly more frequent without SMAS flap reconstruction (10.16% vs 3.125% [P < 0.05], 13.55% vs 3.125% [P < 0.05], 13.55% vs 3.125% [P < 0.05], 20.33% vs 0% [P < 0.05] respectively). The use of the SMAS flap is able to reduce the cosmetic and functional complications that occur after the removal of a benign tumour of the parotid through the superficial parotidectomy technique, above all, it reduces the occurrence of Frey's syndrome.

The Effects of Superficial Musculoaponeurotic System Flap on the Development of Frey's Syndrome and Cosmetic Outcomes After Superficial Parotidectomy

Objective

To investigate the outcomes of superficial musculoaponeurotic system (SMAS) flap and classic techniques in superficial parotidectomy in terms of Frey's syndrome (FS) and cosmetic satisfaction.

Methods

In this study, a retrospective chart review of patients that underwent superficial parotidectomy was performed. These patients were divided into two subgroups: group 1 included patients in which the SMAS flap was harvested and group 2 comprised the remaining patients on whom classic superficial parotidectomy was performed. All the patients were evaluated clinically and with Minor's starch-iodine test for FS. For the evaluation of the cosmetic results, the patient's satisfaction was queried according to the incision scar and surgical field skin retraction/facial symmetry. Both groups were compared in terms of complications and numbness of surgical area.

Results

Fifty-five patients (31 male and 24 female) with a mean age of 50.19 years were included in the study. Thirty-two patients were in group 1 and 23 in group 2. Thirteen patients (23.7%) described as having FS and six of them were in group 1, while seven were in group 2. Minor's starch-iodine test was positive in nine patients in group 1 (28.1%) and six patients in group 2 (26.1%) (p=1.000). With regard to cosmetic satisfaction, eight patients (25%) stated mild discomfort from the incision scar and two patients (6.3%) stated cosmetic dissatisfaction for facial asymmetry in group 1. In group 2 for the same factors the number of patients were 11 (47.8%) and 2 two (8.7%), respectively (p=0.027). There were no statistically significant differences in means of complication and numbness (p>0.05).

Conclusion

According to our study results, there was no superiority between both the groups in terms of FS and incision scar satisfaction. We determined that there was a significant benefit of SMAS flap application in the prevention of volume loss and surgical area retraction.