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Repair of a postaural fistula with a suprafascial radial forearm free flap
  1. Adam T Misky1,
  2. Allan Ponniah1 and
  3. Dariush Nikkhah1,2
  1. 1Department of Plastic and Reconstructive Surgery, Royal Free London NHS Foundation Trust, London, UK
  2. 2University College London, London, UK
  1. Correspondence to Mr Dariush Nikkhah; d.nikkhah{at}nhs.net

Abstract

We describe the case of a patient with the rare complication of a chronic postaural fistula following repeated and extensive surgery and adjuvant radiotherapy to the head and neck for a pleomorphic adenoma of the parotid gland. This case demonstrates the importance and value of thorough preoperative planning for major head and neck reconstruction, particularly if the area for reconstruction has distorted anatomy due to prior treatment or damage. In complex free flap reconstruction, it is important to investigate the recipient site with the help of arteriography and give due consideration to the donor site and its postoperative management. We highlight the importance of multidisciplinary work for the care of these patients not only intraoperatively, but also in the preoperative planning stage, and perhaps most importantly in the postoperative care.

  • Radiotherapy
  • Radiology
  • Head and neck surgery
  • Otolaryngology / ENT
  • Plastic and reconstructive surgery

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Background

The patient described in this case report had a rare complication of a relatively common procedure in head and neck surgery for a pleomorphic adenoma. The procedure described took place in an area previously treated with radiotherapy, a difficult surgical field that warrants further consideration when thinking about surgical management.

Pleomorphic adenoma is the most common solid salivary gland tumour in children and is therefore something that most head and neck, or ear, nose and throat (ENT) surgeons will encounter throughout their career.1 Complete extirpation of the tumour is advised, to avoid future malignant transformation, which may require a total parotidectomy.1 Facial nerve injury is an established complication of parotidectomy, less is known about other, less common complications, particularly if adjuvant radiotherapy is required.2 Adjuvant radiotherapy may be necessary to achieve local control in cases where the tumour is unresectable, there is multifocal recurrence postoperatively or the resection margins are positive.3

The case demonstrates the importance of multidisciplinary work in the care of a patient with complex reconstructive needs, as well as the importance of preoperative planning in cases complicated by distorted anatomy following radiotherapy.

Case presentation

A healthy woman in her 40s was referred to the plastic surgical service, requiring reconstruction for a persistent postaural fistula. She previously had a right-sided parotidectomy for a paediatric pleomorphic adenoma and required adjuvant radiotherapy due to the unexpectedly large size of the tumour and resultant positive excision margins. Subsequently, she required a subtotal petrosectomy and blind sac closure 18 years after her original parotidectomy, due to recurrent otitis media. This left her with a right postaural fistula that was closed directly 5 years prior to the current referral. Following failure of direct closure there was a second attempt made at closure of the fistula using autologous fat and transposition of the masseter muscle. Unfortunately, 5 months prior to her presentation, her postaural fistula recurred, causing pain, persistent postaural discharge, worsening facial nerve palsy as well as systemic yeast infections. The fistula was deemed unlikely to be amenable to direct closure or other simple closure methods, given the previous extensive radiotherapy to the field and was judged to require free flap closure.

On examination in the plastic surgical clinic, she was noted to have a right postaural fistula actively discharging purulent material. General examination was otherwise unremarkable. There were no clinical signs of active infection, and no positive microbiological samples were ever returned from the fistula.

Investigations

As the patient was likely to require a flap (free or pedicled) for reconstruction following excision of the fistula, a thorough investigation of the surrounding vascular anatomy was required to aid with planning of the microvascular anastomosis. A CT angiogram of both carotid arteries was performed for this reason. A further MRI scan of the head and neck was also performed, to allow accurate mapping of the fistula tract and the surrounding soft tissue anatomy.

Of note, the CT angiogram showed irregularities in the right external carotid artery, as well as all of its branches distal to the right superior thyroid artery, likely secondary to the previous extensive radiotherapy to the right side of the patient’s head and neck (figure 1). A small incidental left anterior tentorial meningioma was also noted on the MRI scan and was advised to be followed up radiologically.

Figure 1

3D angiogram showing poor right external carotid vessel quality compared with left external carotid (both highlighted in red circles).

Treatment

Following extensive preoperative planning and multidisciplinary discussions between radiology, the ENT and plastic surgical teams, it was decided to attempt excision of the persistent postaural fistula and reconstruction with a suprafascial radial forearm free flap (RFFF). Excision of the postaural fistula, as well as associated necrotic skin and adipose tissue, was performed by a consultant ENT surgeon. Necrotic adipose tissue was noted in the cavity previously filled with adipose tissue following the subtotal petrosectomy and previous fistula closure. Intraoperatively, the facial nerve was identified, preserved and good function was demonstrated using a nerve stimulator, and the Eustachian tube was meticulously sealed with bone wax (figures 2 and 3)

Figure 2

Postaural fistula and preoperative markings.

Figure 3

Postauricular defect following excision of fistula and necrotic tissue.

In the meantime, a plastic surgical team templated and raised a suprafascial RFFF based on the postauricular defect in the conventional manner, performing the dissection in the suprafascial plane. The RFFF was harvested with the radial artery at its origin with its two venae comitantes and the cephalic vein, providing a 15 cm long pedicle (figures 4 and 5). Care was taken to ensure the sensory branch of radial nerve remains intact. Preoperatively, good collateral hand perfusion had been determined using Allen’s test. A long pedicle was required to allow it to reach the superior thyroid artery, preoperatively selected as the appropriate recipient vessel. The donor site was closed with a conventional hatchet flap.

Figure 4

Preoperative markings of RFFF.

Figure 5

RFFF with vascular pedicle before flap is disconnected from donor site.

Two experienced plastic surgical consultants then inset the RFFF in the postaural defect. The RFFF was partially deepithelialised to allow it to sit in the defect and the leading edge of the skin paddle was visible through the external auditory meatus. The radial artery was anastomosed to the right superior thyroid vessel end-to-end using microvascular technique. Unfortunately, the first attempt at anastomosis was unsuccessful, as the anastomosis clotted off, after which the patient received 5000 IU heparin intravenously and underwent a second attempt at an end-to-end anastomosis between the same vessels, this time successfully. The cephalic vein and one of the radial venae comitantes were anastomosed end-to-end using microvascular technique to appropriate superficial veins encountered during dissection. The cephalic vein anastomosis was created using a venous coupler, the vena comitans hand-sewn, due to a significant (3:1) size mismatch. Total flap ischaemia time was 2 hours and 50 min. Good flow was seen on Acland test of the anastomosed vessels. The pedicle was buried subcutaneously in its path between the postauricular area and the superior thyroid artery.

Following insetting of the flap, significant bleeding was noted from beneath the flap; therefore, the flap was raised again, and anastomoses were checked for integrity. All anastomoses were intact, and no major bleeding was found. The bleeding was noted to be a result of general capillary oozing around the recipient area. Haemostasis was achieved using Tisseel (Baxter International, Deerfield, Illinois, USA), a fibrin sealant which was applied over the pedicle. The use of fibrin sealants in microvascular surgery has been shown to be safe and have the added benefit of preventing kinking of the vascular pedicle.4

The wound was closed in layers, with a small split thickness skin graft (STSG) harvested and inset in the conventional manner, used to cover a portion of the free flap that could not be buried. Two small open passive drains were left in situ at the recipient site to avoid the formation of a collection (figure 6).

Figure 6

Immediate postoperative appearance of the postauricular reconstruction.

Following the operation, the patient was admitted to the plastic surgical ward for routine free flap monitoring and had an uneventful inpatient stay. She was discharged on the 6th postoperative day and was subsequently routinely reviewed in the plastic surgical dressing clinic as well as the plastic surgical consultant clinic.

Outcome and follow-up

At a plastic surgery consultant clinic review 8 months postoperatively, the patient had a good outcome with excellent healing of both the donor and the recipient sites, as well as 100% take of the STSG on the postauricular area. The RFFF had shrunk down as expected in the immediate postoperative period, which resulted in a functionally and aesthetically pleasing result for the patient (figure 7). The donor site healed well, and the patient regained good hand function with the support of specialist hand therapists (figure 8).

Figure 7

Postauricular reconstruction 8 months postoperatively.

Figure 8

Donor site 8 months postoperatively.

She has had no concerns about recurrence of the fistula; however, at her 8-month review, she noted that the wound within the meatus has opened up slightly, and started occasionally discharging serous fluid. This, however, is a wound healing complication only, rather than a recurrence of her prior issues. A postoperative MRI to investigate patency or recurrence of fistula or malignant disease showed no significant fistula.

Discussion

A persistent postaural fistula is a recognised complication of a subtotal petrosectomy.5 The management of such a fistula, unfortunately, is less well described in the available literature. Most available reports of postaural fistulae describe this complication in cases of chronic otitis media of a variety of aetiologies, and these fistulae are treated with surgical excision and primary closure.6 The authors could not find any reports on the management of recurrent postaural or other head and neck fistulae involving the facial skin.

Dealing with such a rare clinical entity had many challenges. Clearly a multidisciplinary approach was required to plan this patient’s treatment. A multidisciplinary approach in head and neck cancer surgery has long been established and has been shown to greatly aid patient care.7 A similar approach was required for this patient, allowing a frank exchange of ideas between ENT, radiology and plastic surgical disciplines, including specialists in otology, head and neck surgery and microsurgical reconstruction.

In challenging cases such as the one described in this report, further complicated by previous adjuvant radiotherapy to the recipient area, meticulous planning is essential. The reconstructive surgeon will need to consider the ‘reconstructive elevator’ instead of the ‘reconstructive ladder’, as simpler reconstructive methods, such as locoregional flaps, are likely to fail.8 This is highlighted in this case by the failure of the patient’s previous masseter transposition flap. The use of preoperative arteriography for free flaps in patients with coexisting chronic wounds or vasculopathy has long been established.9 Radiotherapy will to some extent affect surrounding normal tissue and can result in changes to the normal vasculature, as seen in this patient’s case. When surgeons are aware of the risk of abnormal anatomy in a recipient area, meticulous mapping of the recipient vasculature is necessary to ensure free flap survival.

A further difficulty in a case such as this is finding the balance between reconstruction of the existing defect and donor site morbidity. The RFFF has long been the workhorse of head and neck reconstruction, due to its thin, pliable nature, as well as its long vascular pedicle.10 It is, however, often associated with significant donor site morbidity, due to disabling functional and/or cosmetic sequelae.11 These can result from tendon or nerve exposure following closure of the donor site defect. It is often necessary to cover the donor site with a skin graft, resulting in further morbidity in yet another area of the patient’s body. Although there exist many ways of closing an RFFF donor site, there are, as of yet, no established protocols for the management of a problematic donor site, despite attempts at creating this.12 In the authors’ experience, the donor site outcome is generally better if a suprafascial flap can be raised and the donor site can be closed directly or with a local tissue flap, instead of a skin graft. We propose that for flaps <5 cm in width a hatchet flap can be used to cover the defect with good postoperative outcome (figures 4 and 8).

This case highlights the many difficulties in planning and executing a complex head and neck reconstruction. It is evident that close multidisciplinary collaboration is required, including not only the multidisciplinary surgical team, but also preoperative planning with a radiologist and postoperative management involving specialist hand therapists to overcome donor site morbidity.

Patient’s perspective

This latest surgery marked a new departure in the management of a situation that has been ongoing since I was 17 years old, and although no medical intervention is without a degree of apprehension for the patient, it was a particularly nerve-wracking and seemingly risky event for me, particularly as it was in the midst of lockdown and I was lacking the support that comes from social interaction.

I have always felt in good hands, however, with the surgical team since being referred by the ENT department and was very aware that this was an option of last resort, in view of the fragility of the bone and tissue concerned. When dealing with such a professional, courteous and caring team, it is easier to address the challenges of surgery and its aftereffects, and to commit to healing from the new wounds it necessarily entails.

It is clear to me that I am likely to continue to face the impacts of osteonecrosis of the jaw, and that the ageing process may present additional challenges, but am confident that the work of the plastic surgical team, and experts from other specialties has gone a long way to securing a healthier immediate future, both for me and my family, and for that I am eternally grateful.

Learning points

  • A multidisciplinary approach involving a variety of healthcare professionals, as well as the patient themselves, is required for successful management of difficult reconstructive cases.

  • Preoperative arteriography is key to finding appropriate recipient vessels for free flap reconstruction in head and neck surgery, particularly in a field affected by radiotherapy.

  • The radial forearm free flap is still a useful flap in head and neck reconstruction. The surgeons, however, must be mindful of the associated donor site morbidity and plan to minimise this with appropriate strategies for donor site closure.

  • When dealing with the reconstruction of difficult fields (such as those that have undergone radiotherapy), the initial approach may need to be a complex free flap reconstruction.

Ethics statements

Patient consent for publication

References

Footnotes

  • Twitter @atmisky

  • Contributors ATM, AP and DN contributed equally to the identification and conceptualisation of the case report. ATM collected images and data, wrote the article and obtained informed consent and patient’s perspective. DN and AP reviewed the manuscript and contributed to its final edition.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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