Avoiding the complications of parotidectomy for benign disease: Intraoperative techniques

Avoiding the complications of parotidectomy for benign disease: Intraoperative techniques

Ayman A Albatanony,a,hMD; Azzam Alkadi,aMD; Ayman H Elgadaa,a,cMD

a) Department of Surgery, Qassim College of medicine, Qassim, Buraida, KSA. b) Department of General Surgery, Menoufiya University, Shibin Alkom, Egypt. c) Department of General Surgery, Zagazig University, Zagazig, Egypt.

Abstract

Parotidectomy for benign disease is the most common indication for parotidectomy. Surgical treatment of benign parotid disease remains a challenging undertaking that is associated with significant postoperative morbidity. The aim of this study is to present our experience with a series  of 29 cases  of superficial parotidectomies, regarding the incidence of the common complications and the techniques we used to reduce the incidence of these complications. We encountered  2 cases (6.9%) of facial nerve dysfunction; both were of a mild degree. We used Ligasure, loupes, nerve monitoring and certain intra operative techniques to achieve such a low incidence of facial nerve dysfunction.  No case of Frey syndrome was encountered, due to the use of expanded poly tetrajluoroethylene sheets. Only 3 cases suffered partial anaesthesia of the ear pinna, as we preserved the trunk or the posterior branch of the great auricular nerve. Salivary fzstula occu"ed in 17.2% of cases, and was mild and was treated conservatively. We recommend sticking to our techniques to decrease the postoperative complications of parotidectomy.

Key words: Parotidectomy, complications, operative techniques.

Introduction:

Parotidectomy for benign  disease  is the most common indication for parotidectomyt 1 and superficial parotidectomy (entailing  the removal of the parotid tissue lateral to the facial nerve and its branches,2  is the most frequently performed  type  of   parotidectomy.3

Parotid gland surgery is problem-prone due to two main  facts:  firstly,  the indication is usually benign, hence the patients expect no complications post-operatively,4 and secondly: it is a technically sensitive surgery because of the close relationship of the gland with the extra-cranial facial  nerve  which  is a motor supply to the muscles  of facial expression.5

Complications of parotid surgery may be intra-operative or post-operative., early or late. Intra-operative complications of parotid gland surgery comprise injury of the facial nerve or one of its branches,  rupture  of the pseudo-

capsule  of a parotid  tumour  or incomplete surgical resection thereof.4

A few of the expected consequences following parotidectomy are ear numbness that may  be temporary or permanent,2 and occasional problems with mastication (gustatory sweating, flushing, itching...).6,7

Surgical treatment ofbenign parotid disease remains a challenging undertaking that  is associated with  significant postoperative morbidity. Some complications are inherent in the nature of the pathology  for which the operation is undertaken; and these need to be taken into account  in preoperative decision making and  patient counselling. Others, however, can result from variations insurgical practice  and could potentially be avoided.8

In this article  we present  our experience with  a  series of  29 cases   of  superficial parotidectomies, regarding the incidence of

the common complications and the techniques we  used  to  reduce  the incidence of  these complications.

Patients and methods:

A retrospective review of 29 consecutive superficial parotidectomies, conducted at the hospitals affiliated with Qassim  College  of medicine, Qassim, KSA, between the January

2009 and January 2012. The pathology reports, operative data and the postoperative course of each patient were studied.

None of the surgeries  was a redo parotid

surgery and none  of the  patients had preoperative facial nerve affection on clinical basis.

Surgical technique:

Hypotensive anaesthesia was used whenever possible. Long-acting paralytic agents  are avoided to allow for facial nerve monitoring.9

The operator used a magnifying  Ioupe in all

cases (x2.5-3.5). Intra operative facial nerve monitoring through  a nerve  stimulator was used in every case and to facilitate this, transparent drapings  were used.l O Typically four electrodes are placed trans-cutaneously in the facial musculature to correspond to the temporal, zygomatic, buccal,  and marginal mandibular branches of  the  facial  nerve.2

The  surgery was  carried out  through a modified Blair incision or a modified face-lift incision.ll The skin in the parotid  area was infiltrated  with  1:80,000  adrenaline.5

Methylene  blue was used to mark points along the proposed  incision and to facilitate proper wound alignment and closure.The skin incision  is made with a scalpel  and carried down through  the subcutaneous tissues and platysma muscle.

An anterior flap was raised trying to keep it as thick as possible,  avoiding violation  of any  neoplasm at the  surface  of the gland.

A posterior, inferior flap is also elevated to

expose the tail of the parotid gland. Silk sutures were used to retract these flaps.

Every effort was made to preserve the great auricular nerve, but if its division was judged to be imperative  for a safe identification & dissection of the facial nerve; or to prevent tumour  cell dissemination, it was sacrificed

preserving its posterior branch.l2 We employed the techniques advised by Vieira et al in 2002.13

The posterior belly of the digastric muscle is exposed with further elevation of the tail of the parotid gland. During elevation of the tail of the parotid, the continuity of the posterior facial  vein  is   preserved  if   possible.

The posterior belly of the digastric muscle serves as a landmark for the facial nerve. The facial nerve  is  identified using  anatomic landmarks, which include the posterior belly of the digastric  muscle, the mastoid  tip, the tragal cartilage pointer, and the tympanomastoid  suture.2

Anterior retraction of the parotid gland was kept gentle, to avoid traction injury of the facial nerve and its branches. Traction was suggested by Nouraei et al to be the main cause of injury to the marginal mandibular  branch, the most commonly injured branch.8

After identification of the facial nerve trunk,

the parotid gland superficial to the nerve is divided carefully.This was achieved by passing a fine mosquito forceps above and parallel to the nerve, spreading it open, elevating it and then, the parotid  tissue above it is removed using a Ligasure Precise®.14 This was repeated tracing the facial nerve branches  distally till removing  the whole parotid gland lateral to the nerve. Anatomic distortion by a neoplasm or  operative manipulation was  constantly considered. In  no case  we needed  to do a retrograde facial nerve dissection.

After the gland was removed, the wound was carefully inspected and bleeding sites were controlled, if any. The integrity  of the facial nerve  is confirmed both visually and by electrical stimulation of the main trunk of the facial nerve  and  its  peripheral branches.

Before  skin closure, defect  filling  in the parotid area was performed in all patients. An expanded polytetrafluoroethylene (e-PTFE) (GoreTex®) sheet was used. Parotid duct was not sought nor ligated routinely. The wound is irrigated, realigned, and closed in layers on a suction drain.

Results:

Data were presented either as means with standard  deviations  or as percentages when appropriate.

Demographic data:

Out of the 29 patients included in this study there were 18 men (62%) and 11 women. The average age was 51±11.6 years (range: 29-73 years). The right side was affected  in 56% of cases. Benign parotid neoplasms (pleomorphic parotid adenoma, adenolymphoma and parotid lipoma) were the cause of surgery in 26 patients and chronic inflammation in 3 patients. The average operative time was 151±40.2 minutes (range: 120-223 minutes). In no case the intra operative blood loss exceeded 140ml. Post operative facial nerve affection:

Facial nerve  function was evaluated at 1 day, 1 month  and 6 months postoperatively, using the House-Brackmann grading system.lS A degree of facial nerve affection was found

in 2 cases (6.9%) in the study group. According

to the House-Brackmann grading system, the affection was mild in both cases (i.e. grade 2 and 3), and both regained normality by the end of the 6 months follow-up period. Both cases were inflammatory not   neoplastic cases. Frey syndrome (gustatory sweating):

All the patients were assessed clinically for the presence of Frey syndrome at one and six month's visits. None of the patients complained of Frey syndrome or other problems related to mastication.

Anaesthesia/parathesia in the ear  pinna:

3 patients (10.3%) complained of a degree of anaesthesia in the ear pinna that was tolerable and were improving on the 6 month follow up visit.

No post operative haemorrhage nor infection

were reported. Transient salivary fistula  was noted  in 5 patients (17.2%) and both  settled within a few weeks of conservative treatment. Seroma was reported in 4 cases, and all were treated with repeated aspiration and disappeared within  3 weeks  of surgery. 1 case developed a keloid at the scar  site.  Recurrence of the tumour was  not  evaluated due  to  the short follow up period.

Discussion:

The incidence of facial nerve dysfunction in our study was 2/29 (6.9%),  and both cases were mild affection that improved completely within few months of surgery (1 case resolved in  6  weeks, and  1 case in  16 weeks). The

incidence and severity of facial nerve affection in the current study is lower than that reported by many authors. Nouraei et al in 2008 wrote: "Postoperative facial  nerve  dysfunction is a common finding, affecting 30-60% of patients following parotidectomy, and although most cases are  transitory in  nature, it can, nevertheless, be associated with  significant morbidity and distress".8

According to Wang  and Eisele, temporary facial nerve paralysis involving all or just one of the branches of the nerve occurs in 10-30% of  parotidectomies.2 In  2011, Amin et  al reported that2 cases out of23 (8.7%) developed transient facial nerve affection.17

The relatively low incidence in the current study was  the  cumulative effect of  many factors. Hypotensive anaesthesia helped in maintaining a dry field as  did  the  local infiltration with  adrenaline. The  use  of  a surgicalloupe allowed better identification of the tissues,  a subtle step overlooked by quite a few surgeons; for example Sharma and Sirohi in 2010 reported 5/17 (29.4%) of facial nerve dysfunction  postoperatively  when  no

magnification was used.s The value  of using

the  Ioupe  was  also  pointed   out  by

Papadogeorgakis  et  aJ18   and  Pai.19

Identification of the main trunk of the facial nerve  was  a crucial step. One  should  avoid going directly to the facial  nerve  trunk area before identifying the anatomic landmarks.20

In this study we followed the time-honoured classical 4landmarks.2 There  are more  than

15 landmarks that can be used for identification of the main trunk of the facial nerve,21 however, we found the classic four ones more consistent, specially the  tragal pointer. This was  in accordance with Rea et al, who studied  these four landmarks extensively.22 A modification of the use of these 4 landmarks was proposed by  Pereira et  al, and  we  also found this technique helpful.23  The advices of O'Brien et al were also honoured.24

Intra-operative facial nerve monitoring helped in decreasing the  incidence of facial nerve dysfunction. It was  pointed out  by Pienk.owski et al in 2010  that intra-operative facial  nerve monitoring should  be a standard procedure during parotid gland surgery inmost clinical situations.lO Lowry  et al also  found

that the use of facial nerve monitoring reduced the likelihood of the surgeon  being sued by more  than  20%.25 Another subtle step  is ignoring the parotid duct. It is better not to be sought for nor ligated. Olsen in 2004 advised "do not look for the parotid duct or try to isolate it after raising the cheek flap as this puts an unnecessary risk of injuring the small buccal nerve  branches that  often  accompany the duct".26 We also believe that using the Ligasure Precise® for dissection was a crucial step. The incidence  of facial nerve injury in this study (6.9%) is comparable to that reported by Michel et al (4%), who used a tissue welding forceps for dissection during  parotidectomy.27 An interesting fmding  in our study is that both cases of facial nerve affection were encountered in inflammatory  cases. This is in accordance with Gaillard et al., 2005.28 We depended on the clinical-based system  for evaluation of facial nerve function because it is evident that there is no subclinical affection of facial nerve following parotidectomy,16 hence no need for electro-physiological evaluation.

Frey  syndrome is a quite  common and unpleasant complaint, observed in up to 40% of patients after parotidectomy and is a potential cause of patient embarrassment, and may limit the patient's quality oflife.7 We encountered no  cases  suffering clinically from  Frey syndrome within the 6 months follow up period. The factors contributing to this in our opinion are mainly two factors: keeping the raised flaps as thick as possible without risking opening the  tumour pseudo-capsule, and  more importantly, the mechanical barrier we used, i.e. the e-PTFE  sheet.  The insertion of the mechanical barrier  virtually eliminates any possibility  of Frey syndrome, as it prevents the cross  regeneration of nerve  fibers,  the hypothesis agreed  to be the  cause  of  this syndrome.29  Guo et al in 2005 reported also a zero percent incidence of Frey syndrome in e­ PTFE-implanted cases.30

Many types of mechanical barriers  were described  (Oxidized regenerated  cellulose,31

Lyophilized Dura and  polyglactin & polydioxanone mesh,32 dermofat  graft,33 fat injection,7 superficial temporal artery fascia flap34  & superiorly based superficial sternocleidomastoid flap,17) but   in many

respects, e-PTFE implants represent the ideal solution since they are not resorbed, exhibit good biocompatibility, and  low tissue reactivity.35 We also agree with Guo et al that the aesthetic effects of the use of e-PTFE were very  good. The  advantage of  being  non­ absorbable was also a disadvantage of e-PTFE, as it acts as a foreign body in the wound, thus causing salivary fistula.  We encountered 5 cases (17.2%), a percentage that is lower than that reported by Dulguerov et al in 1999, who reported a 25% incidence of salivary fistula in the e-PTFE-implanted patients.32 All the fistula cases  in our study, as in theirs', eventually closed  with  conservative  treatment.

We managed to preserve the great auricular nerve main trunk in 26 cases (89.6.1%). The trunk had to be sacrificed in 3 cases (10.3%), due to the close proximity with the tumour and in these three cases; we managed to preserve the posterior branch alone. This may had been one  of  the  causes for  a relatively longer operation time than reported.

Sensory disturbance of the pinna as a result of excising the great  auricular nerve  often reduces the quality of life of the patients who have undergone parotidectomy,36 We agree with Vieira et al that preservation of the great auricular  nerve or its branches is technically feasible during parotidectomy.13 The average operative time was comparable to that reported in the 1iterature13 and this could be explained by the  time saving using Ligasure37 compensated for the time loss of both great auricular nerve  preservation and  e-PTFE insertion.

Conclusion:

The use of facial nerve monitoring, Ligasure as well as sticking to the fine operative details can  decrease post  operative facial nerve dysfunction. The use of e-PTFE is advisable to eliminate the incidence of Frey syndrome; however transient salivary fistula  is to be anticipated. Great auricular nerve can be saved in the majority of cases.

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