Medial sural artery perforator flap following orbital exenteration
- Daniah ALNafisee ,
- Taylor Cave and
- Brent A Chang
- Department of Otolaryngology, Head and Neck Surgery, Mayo Clinic Arizona, Scottsdale, Arizona, USA
- Correspondence to Dr Daniah ALNafisee; dnafisee@gmail.com
Abstract
An extended orbital exenteration defect in a male in his mid-80s was successfully reconstructed with a medial sural artery perforator flap. To our knowledge, this flap has not been described in the literature for such defects until now. While it may require meticulous intramuscular perforator dissection, it provides several advantages; it is thin, pliable, has a long pedicle of large calibre facilitating microanastomosis and provides adequate coverage where the amount of chimeric muscle can easily be tailored to the defect’s surface area and volume. In addition, its robust vascular supply can withstand volume changes post radiation therapy. Two years after surgery, the patient has healed well with an excellent functional outcome.
Background
Orbital exenteration (OE), first described by George Bartisch in 1586, involves removing the entire orbit including the ocular globe, eyelids, lacrimal gland, conjunctival sac, retro-bulbar tissues and surrounding periosteum.1–3 The remaining defect tends to be complex, especially when it involves other surrounding structures such as the skull base, paranasal sinuses, maxilla and nose.1 The primary goal of reconstruction is to maintain separation between the cavity (orbit) and these structures.1 The secondary goal is to reconstruct facial contour and to restore appearance and function. Moreover, shorter healing times are desirable, as many patients undergoing this procedure will require adjuvant radiotherapy.1
Several strategies have been described to reconstruct orbital defects from secondary intention and split thickness skin grafts to regional pedicled and free flaps.1 The specific reconstruction choice may be influenced by a number of variables including extent of the defect, patient anatomic factors, surgical expertise and patient interest in prosthetic options. Larger, more advanced defects may require free tissue transfer.1 To our knowledge, this is the first case report describing correction of an OE defect with a medial sural artery perforator (MSAP) flap.
Case presentation
An elderly male in his mid-80s with several comorbidities and a medical history of anorectal carcinoma presented with a left lacrimal sac mass and persistent epiphora. Three years prior, he had been treated for a dacryocyst with multiple recurrences. While under the care of an outside ophthalmologist, he underwent incisional biopsy showing papillary squamous cell carcinoma. On physical examination, he was alert and orientated with no obvious distress. He had a 2-cm left lacrimal sac nodular mass with extension into the inferior eyelid and posterior lateral displacement of the globe. There was no palpable cervical or parotid lymphadenopathy. His Allen’s test was negative bilaterally with poor perfusion through the ulnar system.
Investigations
The patient was assessed with several radiological scans. CT sinuses showed a left medial canthus soft tissue mass with destruction of the left inferior lamina papyracea. CT neck with intravenous contrast showed no evidence of lymphadenopathy. MRI of the orbits with and without intravenous contrast confirmed a 2-cm left lacrimal sac mass with a small anterior cystic component and a fluid level with extension into the left ethmoid cavity along the middle turbinate with no involvement of the nasal septum. Positron emission tomography CT from skull to thigh indicated a left medial orbit hypermetabolic mass with no evidence of metastasis.
Differential diagnosis
The differential diagnosis for the first 3 years was dacryocyst and was drained on two separate occasions. When the eye swelling failed to resolve and recurred for the third time, an incisional biopsy was sent to pathology and papillary squamous cell carcinoma was diagnosed.
Treatment
The patient was keen for a curative intent approach. Due to the mass being in close approximation to the globe and the need for adequate surgical margins, an OE was performed (figure 1).
Orbital exenteration extended to the maxillary and ethmoid sinuses post papillary squamous cell carcinoma excision.
A left-sided ethmoidectomy, medial maxillectomy, superficial parotidectomy and frontal sinus osteoplastic flap were completed for oncologic clearance. The superficial parotidectomy was performed prophylactically as it was thought to be the most likely first echelon nodal drainage basin.
The patient was then positioned in a frog-leg supine position in preparation for the flap harvest. An elliptical, 6×11 cm MSAP flap was designed pre-operatively along an axis from the right midpopliteal crease to the medial malleolus. Perforators approximately 8 cm from the midpopliteal crease were mapped using a Doppler probe and confirmed with intraoperative inspection. Preoperative imaging for perforator mapping was not used. More than one perforator was identified, but the more distal one was chosen in order to shift the skin paddle distally and provide a longer pedicle length. The perforator was closely traced to the medial gastrocnemius muscle until the medial sural artery was encountered. The pedicle was dissected proximally until its takeoff from the popliteal artery and distally where it was ligated, taking a small additional chimeric muscle component (6×4 cm of medial gastrocnemius) based off the distal vascular pedicle (Figure 2). The overall length of the pedicle was 11 cm with a 2-mm diameter artery and 2.5 mm diameter vein.
Chimeric skin paddle and medial gastrocnemius muscle harvest on separate perforators prior to ligation. The asterisk indicates the location of the MSAP perforators. The arrow indicates the pedicle. MSAP, medial sural artery perforator.
The flap was orientated into the defect and the inset was performed. Deep fascia was anchored superiorly to the supraorbital periosteum without obstructing the contralateral frontal sinus outflow. A subcutaneous tunnel was created between the defect and the superficial temporal vessels. Microvascular anastomosis was performed using the superficial temporal artery and vein. The leg defect was primarily closed following suprafascial undermining. The flap showed no signs of vascular compromise in the immediate postoperative period (Figure 3) or otherwise. The total operating room procedure time was 380 min long.
Immediate postoperative view of the MSAP flap inset. MSAP, medial sural artery perforator.
Throughout his admission, the flap demonstrated good perfusion and showed no signs of vascular compromise or dehiscence. He was tolerating an oral diet and his pain was well controlled prior to discharge on day 7.
Outcome and follow-up
Four months postoperatively, the patient was followed up in the outpatient department after completing adjuvant radiotherapy (Figure 4). There was some expected bulk reduction of the flap. Some pigmented desquamation at the borders of the flap was seen and the dried skin was debrided. His main complaint was left-sided intermittent nasal congestion that was well tolerated. The patient also experienced several episodes of epistaxis after discharge from the hospital, one leading to a transfusion. This was managed successfully in an outpatient setting using endoscopically placed haemostatic agents and a small amount of absorbable packing. The patient had minimal donor site issues and did not need any rehabilitation/physiotherapy afterwards. He did not have any movement restrictions and was very pleased with the functional outcome of his donor site (figure 5). Currently, he is 21 months following the completion of adjuvant radiation and is doing well. The patient will continue to undergo routine oncologic surveillance. He declined assessment for prosthesis and wears an eye patch as needed.
Appearance at 4 months following surgery shows flap bulk reduction from radiotherapy and slight pigmented desquamation at the borders of the flap.
Patient’s right calf 9 months postoperatively showing a maturing scar that has healed unremarkably.
Discussion
The reconstruction of OE defects requires careful consideration of a number of variables. Patient variables including anatomy, medical comorbidity, donor site morbidity, patient preferences and specific needs of the reconstructive site including functional and cosmetic outcomes, are of obvious importance. In addition, other variables such as surgical expertise, local hospital resources and input from adjunct specialists such as radiation oncologists and prostheticians must also be considered. In this report, we describe a unique use of the MSAP flap that highlights many of these considerations.
Reconstruction of the orbit is unique in many ways, even within the head and neck. Some examples of these unique considerations include the highly sensitive cosmetic implications of this area, risk of fistula to surrounding areas and possible prosthetic use afterwards. The full spectrum of reconstructive options may be considered in OE defects, including primary closure (of eyelid skin), secondary intention, skin grafting, regional pedicled flaps and free flaps. Less involved options such as secondary intention or skin grafting are viable options in some circumstances.1 4 While secondary intention may allow for easy detection of local cancer recurrence,5 there is a risk of orbital fistula formation and the delayed wound healing may affect the ability to undergo adjuvant radiotherapy in a timely fashion.1 3 Orbital periosteum is also often resected in OE defects, which may reduce the likelihood of success with such reconstructive methods. Regional pedicled options such as the temporoparietal fascia and cervicofacial advancement flaps can often be used for OE reconstruction but were thought to be inadequate in this case due to the soft tissue coverage needs.1 Based on these limitations, our discussion here will largely focus on different free flap options.
In this specific patient, a number of reconstructive variables were considered. The defect was deep with absence of eyelids and surrounding soft tissue, with extension into the sinonasal cavity. The specific defect warranted reconstruction that was relatively thin and pliable to allow for appropriate facial contour restoration but also was deemed to benefit from muscle in order to seal off the sizeable communication with the nasal cavity and reduce the risk of an orbital fistula, particularly given the high likelihood of postoperative adjuvant radiotherapy. For orbital reconstruction, pedicle length is also a consideration, with a longer vascular pedicled often being favourable, as in this case. For such defects, the common choices for free flap reconstruction are the radial forearm free flap (RFFF) and the anterolateral thigh flap (ALTF). While the radial forearm provides thin tissue that can be favourable for relining the orbital cavity, the lack of muscle can be detrimental. Alternatively, the ALTF provides abundant muscle but can often suffer from an adipose layer that is too thick for orbital reconstruction.3 This specific patient failed an Allen’s test bilaterally and the amount of subcutaneous in the lateral thigh area was considered overly bulky for the defect. Other similar options, such as a rectus abdominis musculocutaneous flap,6 were deemed to not be favourable based on patient preference, anatomy and donor site considerations.
After careful discussion and shared decision making with the patient based on patient preference, reconstructive needs and donor site morbidity profile, the decision to perform an MSAP was made. This flap has recently become more popular for head and neck reconstruction. Originally described by Hallock et al and then further by Cavadas et al, the MSAP is a thin, pliable and versatile flap.7–9 In head and neck reconstruction, the MSAP is often described as a substitute or backup for the radial forearm flap, although it should be noted that it is not quite as thin as the RFFF. The medial sural artery originates from the popliteal artery and supplies the medial gastrocnemius muscle. It also sends off several perforators to the skin area covered by this muscle.8 While this flap may require meticulous intramuscular perforator dissection, it provides a long vascular pedicle with a suitable diameter and low donor site morbidity.7 8 10 11 When considering this flap, the specific thickness in the medial sural area should always be assessed on an individual basis.
For this specific patient, the MSAP was deemed favourable for a number of reasons. The thickness of the medial sural soft tissue was the ideal balance for contouring the orbital cavity while also providing enough tissue for adequate healing. This is made even more favourable by the ability to tailor the amount of chimeric muscle to the defect in terms of surface area, volume and distance from the skin paddle. The patient also was highly interested in the potential for low donor site morbidity from this specific flap, based on his lifestyle and functional status.
This patient ended up doing very well from both an oncologic and functional standpoint. He did not require any secondary revision procedures. He ended up electing not to pursue any prosthetic options. Subsequent outpatient clinic visits showed excellent healing at both the donor and recipient sites.
In conclusion, the MSAP flap offers a number of unique advantages for orbital reconstruction and has a favourable donor site morbidity profile. It should be considered as an option in the reconstructive surgeon’s toolbox for the reconstruction of select OE defects.
Patient perspective
At the time of the diagnosis of the relevant cancer, I was a retired university professor in my mid-80s. After completing my education and receiving a bachelors, masters and Ph.D., all in political science, I taught the fields of my specialty (US constitutional law, administrative law and judicial process) for 40 years. At the time of my retirement, I had fortunately never had a serious illness, although I was diagnosed as having atrial fibrillation. Several years later, I was diagnosed as having anal cancer, but it was identified as highly susceptible to treatment by chemotherapy and radiation. I underwent the prescribed treatment, and the cancer has been in remission ever since.
The first indication I had of the cancer was an occasional tearing up of my left eye. I reported this to my ophthalmologist who informed me that I had a cyst which could be dealt with (if it became more troublesome) by draining; or if it persisted, by an operation involving an ear, nose and throat specialist. Ultimately, the cyst did become more troublesome, and it was drained by my ophthalmologist and when it regrew, dealt with in two operations involving an ear, nose and throat (ENT) specialist. After the second operation, my ENT doctor informed me in a short 5-min visit that the pathology report following the second operation found that I had cancer and referred me. I immediately contacted the referred hospital, and at the appointment, the ENT doctor informed me that an operation is needed as I had a good chance of dealing with cancer, but that it would very probably involve the removal of my left eye.
Any cancer diagnosis is of course a source of anxiety, but the prospect of losing an eye made it especially so. In my case, among my greatest pleasures is reading, and much of my time is spent reading newspapers daily, and numerous books, mostly history and murder mysteries, and I was concerned that the loss of an eye could interfere with this source of enjoyment.
I was also concerned whether the loss of my eye at my age would really be worthwhile in relation to my quality of life. After discussions with my wife and my doctor, I decided to consent to the operation.
My operation was the first occasion I had spent a night in a hospital, and I was discharged after a week. The hospital care was excellent, and I could not have expected better treatment during my first experience with hospital care. I experienced no pain from the operation, although it resulted in the left side of my face somewhat deadened and congested. After my discharge, I also experienced frequent bleeding from the left side of my nose. The morning before a follow-up visit with my doctor, the bleeding resulted in an emergency room visit and a blood transfusion. That same day, one of the members of the surgical team repacked my left sinus, and the bleeding discontinued. The most discomfort I experienced after the operation was otherwise from the incision made to my right leg to obtain tissue to make a flap to cover my empty eye socket. After the removal of the drain inserted in the incision, the leg healed rapidly, and the discomfort ended. I underwent 6 weeks of radiation therapy following the operation and this resulted in fatigue and a loss of taste, making eating difficult because of loss of appetite. Recovery from the fatigue was prolonged by a short bout with COVID-19, but my energy level has now recovered to my pre-operation and radiation therapy level. My ability to taste food has also recovered to an estimated 60% of normal, and I am able to enjoy most foods at pre-treatment level. My sense of smell, however, is largely gone and does probably reduce my ability to fully recover my ability to taste food. The loss of my left eye has not interfered unduly with my enjoyment of reading, although using only one eye for reading does increase eye fatigue more than normally would be the case. Loss of depth perception was an initial problem, but I believe one learns to compensate for this over time. I continue to drive regularly and recently had my driver’s license renewed, but I drive less in heavy traffic than previously. Although we still travel, my wife now does most of the long-distance driving.
The care I have received from my ENT doctor and the staff at the hospital has been uniformly excellent. Although the decision to undergo the recommended surgery for my cancer which necessitated the removal of my left eye was a difficult one, it was I think the correct one for me.
Learning points
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The medial sural artery perforator (MSAP) flap is a good option to reconstruct an extended orbital exenteration defect.
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The MSAP flap has minimal donor site morbidity.
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The MSAP flap has a long vascular pedicle with a suitable diameter making the microsurgical anastomosis relatively easy.
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The MSAP flap has a robust blood supply that can withstand volume changes, especially in the radiated patient.
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One main disadvantage of the MSAP flap is it requires meticulous intramuscular perforator dissection.
Ethics statements
Patient consent for publication
Footnotes
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Contributors The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content: DALN and BAC. The following authors gave final approval of the manuscript: BAC, TC and DALN. BAC (BC) is responsible for the overall content as guarantor.
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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.
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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.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.
References
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