Extracapsular Parotidectomy: A Safe Alternative to Partial Superficial Parotidectomy in Properly Selected Patients

Abstract

Objective

Partial superficial parotidectomy (PSP) is the surgical option of choice for treating benign tumors in the superficial lobe of the parotid gland. The less invasive extracapsular parotidectomy (ECP) technique was previously described. Our goal was to review our PSP and ECP cases and compare the outcomes and complications between the surgeries.

Study Design

Retrospective cohort review.

Setting

Tertiary care hospital.

Methods

We reviewed the medical records of 98 consecutive with benign parotid tumors restricted to the superficial lobe who underwent parotid surgery. The cohort was divided into 2 groups—ECP (41 patients) and PSP (57 patients). The demographics, tumor size and pathology, operative time, postoperative complications and recurrence rates were compared.

Results

No significant differences were found between the groups regarding age, gender, body mass index (BMI), and final tumor pathology. Moreover, no significant association was found between the tumor‐specific pathology and the surgery type performed. The mean tumor diameter was significantly smaller in the ECP group compared to the PSP group. The operative time was significantly shorter in the ECP group than in the PSP group.

Conclusion

ECP is a safe alternative to PSP in properly selective benign parotid tumors. ECP has a significantly shorter operative time. ECP does not increase the risk of complications related to parotid surgery, including facial nerve paralysis.

Partial superficial parotidectomy (PSP) is the gold standard for the excision of benign tumors localized in the superficial lobe of the parotid gland. The surgery entails partially or fully identifying the facial nerve within the parotid gland, followed by the excision of the tumor with a cuff of normal surrounding parotid gland tissue. PSP generally carries a low risk of complications, including hematoma, facial nerve paralysis, tumor recurrence, and Frey syndrome.

In the past 15 years, several publications have advocated for extracapsular parotidectomy (ECP) as a less invasive alternative to PSP for the excision of benign parotid tumors within the superficial parotid lobe. ¹ ECP entails dissecting the parotid tumor off the surrounding parotid tissue while keeping the tumor capsule intact. This is in contrast to tumor enucleation where the tumor capsule is incised and only the content of the tumor removed. While restricted to relatively small tumors, ECP has been shown to carry a low risk of facial nerve injury and no additional morbidities compared to PSP. Nonetheless, PSP has remained the preferred surgical technique by most surgeons. The general adoption of ECP as a serious option for benign parotid tumors has been slow, mainly due to fear of injuring the unidentified facial nerve and/or tumor capsule breach and spillage.

In 2016, we started performing ECP as an alternative to PSP in a highly selected group of patients. This study aimed to analyze the results of our parotid surgeries performed on benign parotid tumors and compare the relevant outcomes between the PSP and ECP groups.

Methods and Materials

We conducted a retrospective cohort review of all patients who underwent parotid surgery between January 2016 and September 2024. All surgeries were performed by a single surgeon (the lead author). Demographic data, radiology reports, clinical notes, operative notes and times, surgery types, pathology reports, and complications were collected from the hospital's electronic patient record (EPR) system, and are summarized in Table 1. Facial nerve paralysis, seroma/sialocele, hematoma, and Frey syndrome were the specifically addressed complications in this study. Patients with incomplete medical records, malignant tumors, preoperative facial weakness, revision surgery, and those for whom the operation was performed for a reason other than a benign tumor or by a different surgeon were excluded.

Table 1.

Patient Characteristics Table, All Groups (N = 98)

Characteristic	n (%)	Mean (SD)
Age		47.54 (16.95)
BMI		29.94 (6.14)
Largest tumor diameter (cm)		3.29 (2.47)
Length of surgery (minutes)		112.02 (50.33)
Gender
Male	61 (62.2%)
Female	37 (37.8%)
Tumor type
Pleomorphic adenoma	32 (35.2%)
Warthin's tumor	33 (36.3%)
Other	33 (36.3%)
Capsular breech (histophatological)
PSP	2 (2%)
ECP	1 (1%)
Surgical side
Right	49 (51.0%)
Left	47 (49.0%)
Surgery type
PSP	57 (59.4%)
ECP	39 (40.6%)
Facial nerve weakness (transient)
Yes	1 (1.0%)
No	97 (99.0%)
Facial nerve weakness (permanent)
None	100%
Seroma/sialocele
Yes	1 (1.0%)
No	97 (99.0%)
Hematoma
Yes	2 (2%)
No	96 (98%)
Frey syndrome
Yes	1 (1.0%)
No	97 (99.0%)

The cohort was divided into PSP and ECP groups. Demographics, tumor maximum diameter, operative time, final tumor pathology, status of the tumor capsule, and complications were compared. A t‐test was used to compare continuous variables, and Pearson's chi‐square was used to compare categorical data. A P < 0.05 was considered significant. The data were analyzed using SPSS software (v. 29).

Regarding ECP surgery, our technique is similar to those previously described. ¹ Briefly, the patient is kept in a supine position under general anesthesia, with the head facing the contralateral side. Two‐channel facial nerve monitoring electrodes are used to monitor the frontal and marginal mandibular branches. A modified Blair incision is created proportional to the tumor size, followed by raising supraplatysmal flap. Next, a window is created through the parotid capsule over the most prominent part of the tumor (Figure 1). Sharp and blunt dissection along the tumor capsule is then carried out. Frequent stimulation of the parotid tissue, especially on the deep surface, can occasionally reveal a nearby facial nerve branch that can be protected. The mass is excised with its intact capsule, albeit with very little surrounding normal parotid tissue. The parotid capsule window is then reapproximated, if possible, using absorbable sutures, and the skin is closed in 2 layers.

Figure 1.

Extracapsular Parotidectomy. (A) Superficial parotid tumor visible through parotid fascia, (B) extracapsular dissection of the tumor directly on the capsule, (C) parotid capsule defect and superficial parotid cavity after excising the tumor.

Regarding PSP technique, the initial surgical steps of preparation and flap elevation are similar to ESP. The tympanomastoid suture is used as a landmark for the proximal dentification of the main trunk of facial nerve. Relevant branches of the facial nerve are then dissected distally to excised the part of the superficial lobe harboring the tumor.

Results

A total of 115 consecutive cases were reviewed for this study. Seventeen were excluded according to the previously established criteria, which resulted in 98 patients who were closely analyzed. The cohort's demographics, preoperative, operative, and postoperative collected data are summarized in Table 1. Our patient groups were mainly middle‐aged, with a mean age of 47.5. The 2 main tumor pathologies were pleomorphic adenoma and Warthin tumors at 35% and 36%, respectively. Other benign tumors (29%) included enlarged parotid lymph nodes, myoepithelioma, oncocytoma, and lymphoepithelial cysts. The average largest tumor diameter was 3.3 (SD = 1.82). Minor capsular breech was documented in two of the cases in the PSP group and a single case in the ECP group.

Given the early postoperative discharge of benign tumor patient's from our clinic, no long‐term follow up data were available regarding recurrence rates. In the short postoperative period, usually limited to 2 months, there were no identified recurrencies.

The cohort was divided into 2 groups—ECP (41 patients) and PSP (57 patients). Univariate analysis was performed to compare the collected variables between the PSP and ECP groups (Table 2). No significant difference was found between the groups regarding age, gender, BMI, and final pathology. The mean tumor diameter was significantly shorter in the ECP than in the PSP group (2.5 vs 4.0, respectively; P = .008). Furthermore, the operative time was significantly shorter (ie, almost halved) in the ECP versus PSP group (75.1 vs 138.1, respectively; P ≤ .001). No significant association existed between the tumor‐specific pathology and surgery type performed (χ² = 2.53, P = .28).

Table 2.

Univariate Analysis of Continuous Variables (PSP vs ECP)

	PSP	ECP
	Mean (SD)	Mean (SD)	t	Mean difference	95% CI for difference	P‐value (2‐tailed)
Age	45.00 (19.01)	51.10 (13.77)	–1.74	–6.56	[–14.05, 0.92]	.085
BMI	28.69 (6.86)	30.59 (5.19)	–1.38	–1.99	[–4.84, 0.86]	.169
Tumor largest diameter (cm)	4.00 (3.44)	2.54 (1.16)	2.72	1.62	[0.44, 2.80]	.008
Length of surgery (min)	138.10 (50.99)	75.10 (24.64)	7.31	64.66	[47.05, 8 2.28]	<.001

Abbreviations: BMI, body mass index; CI, confidence interval; ECP, extracapsular parotidectomy; PSP, partial superficial parotidectomy.

Facial nerve paralysis was generally uncommon, with a single case of transient facial nerve paralysis occurring in the PSP group. In addition, seroma (requiring needle aspiration) and Frey syndrome were encountered once each in the PSP group. Postoperative hematoma requiring drainage developed in 2 cases (once in each group). The overall incidence of complications was low and did not warrant statistical analysis.

Intraoperative conversion from ECP to PSP occurred in two of our cases. This first case was a 3.4 cm pleomorphic adenoma that was discovered intraoperatively to be a deep lobe parotid tumor with a severely compressed superficial parotid tissue lateral to the tumor. The lower main truck of the facial nerve and its branches were stretched on the lateral surface of the tumor. The second case was a 2.6 cm pleomorphic adenoma with the deep surface of the tumor laying on the main trunk of the facial nerve and the pes anuresis. In both cases, the main trunk of the facial nerve was identified proximally using the tympanomastoid suture as a landmark.

Discussion

Our results indicated an extremely low risk of complications in all analyzed patients regardless of the surgery type (PSP and ECP). ECP had a significantly shorter operative time, almost half the operative time of the PSP group. Moreover, ECP did not increase the risk of complications related to parotid surgery.

While PSP remains the standard of care in parotid surgery for benign tumors, publications as early as the late 1990s have discussed the role and safety of ECP. ² In an early study, McGurk et al compared 380 patients who underwent ECP to 95 patients who underwent SPS. The study demonstrated the safety and low recurrence rate of ECP. ² Since then, other published studies have reaffirmed these findings and confirmed the utility of ECP in benign tumor parotid surgery. ³ , ⁴ , ⁵ , ⁶ , ⁷ , ⁸ , ⁹ , ¹⁰

A 2015 meta‐analysis of 1882 parotidectomy patients compared the outcomes of ECP to superficial parotidectomy (SP). The ECP group showed a significantly lower rate of transient facial nerve paralysis and Frey's syndrome, with a comparable rate of permanent facial nerve paralysis compared to the SP group. ³ A more recent meta‐analysis, published in 2021, compared different parotid surgeries and their rates of complications. While the enucleation of intraparotid tumors was associated with the lowest rate of transient facial nerve weakness (2.6%), it was associated with the highest rate of tumor recurrence (14.3%). The study documented significantly lower rates of transient facial nerve weakness, Frey's syndrome, and salivary fistula in ECP than in SP patients. ⁴

Several recent publication have also advocated for ECP for certain parotid tumors. ⁶ , ⁷ , ⁸ , ⁹ , ¹⁰ Zhangi et al compared ECP to traditional SP in 56 patients. All surgeries were performed by the same surgical team. Complication rates were statistically lower in the ECP group. All complications related to ECP were minor and included retroauricular nerve injury and sialomas. Mantsopoulos et al. reviewed their parotid surgeries from year 2000 to 2022 and noticed a gradual increase in the rate of performing ECP compared to more invasive parotid surgeries over the specified time period. Further, they observed lesser complications and better functional outcomes with ECP. ⁷ With regards to Warthin tumor, Bonavolontà et al. studied 224 patients that underwent parotid surgery for Warthin tumor (130 ECP vs 94 SP). Facial nerve palsy, Frey's syndrome, and bleeding were found to be less in the ECP group. ⁸ While not our practice, ECP was also utilized for carefully selected malignant parotid tumors. Mantsopoulos et al reviewed 16 cases of ECP performed on malignant parotid tumors with a mean follow‐up of nine years. There were no facial nerve injuries or disease recurrence after 5 years of follow‐up in their cohort. The authors concluded that ECP seems to be a safe option for carefully selected early‐stage malignant parotid tumors. ⁹ Vanroose et al analyzed 161 unilateral parotidectomy cases (59 SP vs 102 ECP). The operative time, anesthesia time, and length of stay were significantly longer in the SP group. Furthermore, the transient facial nerve paralysis and hematoma rates were significantly lower in the ECP group. Therefore, the authors concluded that ECP can be a more cost‐effective options compared to SP. ¹⁰ In a more recent meta‐analysis by Salzano et al of 21 studies including 2507 patients found a low rate of capsule rupture with ECP (4%) and similar recurrence rate between ECP and PSP (3% vs 4%). Similar to other studies, they found a lower rate of transient facial nerve paralysis and postoperative complications in the ECP groups. ¹¹

Despite our accurate perioperative data documentation, long‐term follow‐up data were unavailable given the usual early discharge of benign tumors from our clinic and the overall low risk of capsular invasion and recurrence. Our research was a retrospective study of nonrandomized groups and was subject to selection bias. Tumors eligible for ECP in our practice were smaller in size and this could have been a major contributor to the shorter operative time noticed in the ECP group. However, to decrease other sources of data's heterogeneity, we restricted data collection in our study to consecutive patients operated on by a single surgeon. Further, we have a strict selection criteria for considering ECP:

• (1)benign tumors (confirmed by fine needle aspiration cytology),
• (2)mobile tumors on physical examination,
• (3)size ≤3 cm in their largest diameter,
• (4)tumors located in the superficial lobe directly under the parotid capsule, and
• (5)intraoperative nerve integrity monitoring.

Modern parotid surgeons commonly uses intraoperative nerve monitoring, magnification lenses (ie, loupes), and delicate vascular sealing instruments. These surgical aids have permitted a more precise and earlier identification of the facial nerve and tumor capsule, and the subsequent safe excision of tumors. In our series, ECP was converted to PSP in 2 cases, and in both circumstances the loupes and nerve monitoring assisted in the early identification of the nerve and avoiding accidental injury. Furthermore, high‐resolution imaging (eg, CT and MRI) has allowed for the accurate localization of the tumor within the parotid gland tissue and identifying the superficial parotid tumors that are located directly under the parotid capsule. Given these accurate medical imaging and modern surgical techniques, considering ECP for some properly selected benign parotid tissue has become a rational decision.

We recommend that ECP always be performed by an experienced, high‐volume surgeon. If the need arises, the surgeon must comfortably convert from ECP to PSP and identify the facial nerve in an antegrade or a retrograde fashion. The surgeon must also be familiar with the nerve integrity monitoring system and its troubleshooting. Additionally, we found that using a modified Blair incision on most patients, proportional to the size of the tumor, allowed for a smooth conversion to PSP when needed.

We prefer raising supraplatysmal flaps to avoid accidentally breaching the parotid capsule and tumor spillage. Hemostatic‐promoting agents to improve hemostasis after the tumor excision are not routinely used. The judicious usage of microbipolar at a low‐power setting often suffices. Drains are used in cases where a large empty cavity remained after the tumor excision.

The risk of facial nerve paralysis (transient or permanent) is extremely low with ECP and was not present in our studied cohort. Another concern regarding ECP is its lack of the cuff of normal parotid tissue excised around the tumor, especially with pleomorphic adenoma tumors. ECP was previously shown not to increase the risk of tumor capsule rupture or subsequent tumor recurrence more than other parotidectomy techniques. ⁵ In our series there were three cases with documented capsular breech, albeit minor, 2 in the PSP group and one in the ECP group. On the rare occasion of intraoperative tumor capsule breech, we used copious amounts of normal saline to irrigate the tumor bed after excision.

Conclusion

Modern parotid surgery for benign tumors, including PSP and ECP techniques, has a very low risk of facial nerve paralysis (transient or permanent) and other complications. In carefully selected tumors, ECP is a safe surgical alternative to PSP and can halve the operative time without any additional risk of complications.

Author Contributions

Mohammed Njoom: data collection and analysis; Mazin Merdad: reviewing data, writing the manuscript.

Disclosures

Competing interests

None.

Funding source

None.