Innovative Approaches for Utilizing the Fibula Flap Skin Paddle in the Presence of Alternate Vessel Anatomy—A Report of Three Clinical Cases

ABSTRACT

The fibula free flap is a versatile option for reconstructing complex defects, particularly in the head and neck region. However, variations in the vascular anatomy of the skin paddle can pose challenges during flap harvest and inset. We identified three clinical cases of patients who were found to have alternative or aberrant vessel anatomy to the fibula skin paddle. Operative notes and photo documentation were used to determine variations in vessel anatomy to the fibula skin paddle. A total of three cases were identified in which alternative or aberrant vessel anatomy was noted to the fibula skin paddle. Variations identified included skin paddle perfusion via a perforating branch of the posterior tibial artery, a perforating branch of the tibioperoneal trunk, and absence of distal perfusion requiring use of a proximal peroneal artery perforator. There were no cases of partial or total flap loss or incidences of reoperation. These findings illustrate that awareness of potential vascular variations and management strategies, such as identifying alternative vascular sources and utilizing flow‐through flaps or freestyle perforator flaps, can help to successfully harvest and inset the fibula skin paddle in the presence of alternate vessel anatomy. An alternate donor site may be necessary when no suitable perforators are identified.

1. Introduction

The fibula free flap is a workhorse flap in reconstructive surgery, particularly in the reconstruction of complex defects in the head and neck region. Its versatility, robust vascular pedicle, and the potential for incorporating skin, muscle, and bone make it a preferred choice for a variety of reconstructive indications (Chang et al. 2008; Chang and Weber 2005; Hanasono et al. 2010; Hidalgo and Pusic 2002; Taylor et al. 2009; Clemens et al. 2012; Jones et al. 2012; Yazar et al. 2004; Salgado et al. 2011). However, variations and anomalies in vessel anatomy can pose significant challenges during surgical execution, potentially compromising flap viability and patient outcomes. The skin paddle component of the fibula free flap plays a pivotal role in providing soft tissue coverage over the reconstructed area and is traditionally based on the cutaneous perforators arising from the peroneal vessels. In cases where alternative vessel anatomy is encountered, such as variations in vessel source or absence of expected perforators, the conventional approach may become inadequate, necessitating alternate strategies to allow utilization of the skin paddle.

This report aims to offer practical guidance to reconstructive surgeons faced with challenging vascular variations in fibula flap surgery by synthesizing existing clinical experiences. We first elucidate the relevant anatomical considerations, focusing on the typical vascular anatomy and variations encountered. Subsequently, we explore alternative strategies devised to address alternate vessel anatomy, including modification of flap design and utilization of supplementary vascular sources.

2. Case Reports

Cases in which alternative or aberrant vessel anatomy of the fibula skin paddle occurred were collected by the senior author (P.Y.) at the University of Texas M.D. Anderson Cancer Center. A retrospective review of these cases was performed to determine management strategies of the cases encountered. Notably, there were no incidences of partial or total flap loss and all patients went on to heal uneventfully with routine follow up and stable reconstructive outcome for greater than 1 year.

2.1. Case Report 1—Skin Paddle Supplied by Perforating Vessels From the Posterior Tibial Artery

A 66‐year‐old female with a history of dermatofibrosarcoma protuberans (DFSP) of the chin underwent marginal mandibulectomy and reconstruction using a lateral arm flap, followed by adjuvant radiation therapy. She subsequently developed osteoradionecrosis (ORN) of the mandible, requiring segmental mandibulectomy, boney reconstruction of the mandible, and stable soft tissue coverage of the chin. The anticipated reconstruction was an osteocutaneous fibula free flap utilizing the skin paddle for neck resurfacing. Intra‐operatively, two sizeable perforators, “A and B,” were noted to take an intra‐muscular course through the soleus muscle, and further dissection revealed that the perforators originated from a common branch off of the posterior tibial vessels. There were no perforators from the peroneal vessels. The skin flap was then harvested based on perforating vessels from the posterior tibial vessels and connected to the distal ends of the fibular vascular pedicle in a flow‐through fashion to create a “fabricated chimeric flap” (Figure 1). The peroneal artery was anastomosed to the facial artery using 9–0 nylon suture, and the peroneal vein to the facial vein using a 4.0 mm coupling device.

FIGURE 1.

Skin paddle supplied by perforating vessels from the posterior tibial artery.

2.2. Case Report 2—Skin Paddle Supplied by Perforating Vessels From the Tibioperoneal Trunk

A 71‐year‐old female presented with T4N1M0 (Stage IV) squamous cell carcinoma of the right mandibular gingiva. She was found to have an intra‐oral lesion on dental examination. She had no prior history of radiation or chemotherapy. On evaluation, PET/CT showed FDG avidity at the right mandible and bilateral necks. Therefore, she underwent mandibulectomy, bilateral neck dissection, and tracheostomy and required reconstruction of the mandible and intra‐oral defect. Dissection of the fibula flap demonstrated sizeable B and C perforators to the overlying skin. Further dissection revealed that the perforators were musculocutaneous and arising from the tibioperoneal trunk (Figure 2). The osseous fibula flap was anastomosed to the facial artery using an 8–0 nylon suture and the facial vein using a 4.0 mm coupling device. The skin paddle, based on perforating vessels from the tibioperoneal trunk, was then harvested to reconstruct the intra‐oral defect and anastomosed to the lingual artery and a branch of the internal jugular vein using a 4.0 mm coupling device.

FIGURE 2.

Skin paddle supplied by perforating vessels from the tibioperoneal trunk.

2.3. Case Report 3—Absence of Suitable Distal Perforators; Use of the Proximal “P” Peroneal Artery Perforator

A 67‐year‐old female presented with a complicated history, including lymphoepithelial carcinoma of the base of the tongue, requiring chemoradiation therapy completed in 1996. She subsequently developed squamous cell carcinoma of the left mandibular gingiva requiring wide local excisions and skin grafting in 2019. Unfortunately, she developed recurrent disease in the left oral tongue in 2022, necessitating partial glossectomy followed by a progressive recurrence in 2023. On exam, the patient presented with an ulcerative lesion of the left gingivobuccal sulcus extending to the left posterior oral tongue and into the infratemporal fossa. She underwent tracheostomy, bilateral neck dissection, partial glossectomy, extensive mandibulectomy, from the right parasymphysis to the left temporomandibular joint (TMJ), as well as resection of the disease in the left infratemporal fossa via a coronal incision. A fibular flap with a large skin paddle would need to be harvested to reconstruct the intraoral defect and some soleus muscle, as well as flexor hallucis longus muscle to fill the dead space in the TMJ and infratemporal fossa region. Intra‐operatively, only a distal musculocutaneous perforator C was present. While separating the fibular flap with the FHL from the medial structures, we noticed that a vascular branch originating from the proximal peroneal pedicle traveled in the space between the FHL and soleus muscles and entered the distal soleus muscle where it was divided to free the fibular flap. When the posterior skin paddle incision was made, it was realized that the perforator C did not come from the peroneal pedicle in the distal fibular flap as it is commonly seen. Instead, it came through the soleus muscle and was the continuation of that aberrant vascular branch that had been already divided (Figure 3). This is a rare perforator anatomy that has not been seen in our experience of many hundreds of fibular flaps. Fortunately, a large proximal septocutaneous “P” perforator originating from the proximal peroneal pedicle was present at one‐third from the fibular head upon further exploration, allowing harvest of the skin paddle without additional microsurgical anastomoses (Figure 4).

FIGURE 3.

Absence of suitable distal perforator; perforator not arising from peroneal vessels.

FIGURE 4.

Use of proximal “P” perforator.

3. Discussion

Since the introduction of the fibular osseous flap by Taylor et al. (1975), the osteocutaneous fibula flap for mandibular reconstruction by Hidalgo in 1989 (Chen and Yan 1983), this flap has gained popularity in composite tissue reconstruction of the head and neck and has become the dominant workhorse flap due to its reliability and versatility (Hidalgo 1989). Early use of the flap was plagued by a poor understanding of the vascular anatomy to the skin paddle, resulting in high rates of skin paddle loss (Hanasono et al. 2010; Anthony et al. 1993; Wei et al. 1994; Winters and de Jongh 1999; Baumann et al. 2011). Subsequent anatomical studies have improved understanding and allow for reliable harvest of the skin paddle (Wei et al. 1994; Yu et al. 2011; Carriquiry et al. 1985; Carr et al. 1988; Schusterman et al. 1992; Jones et al. 1996). Preoperatively, the use of duplex ultrasound and/or computed tomographic angiography (CTA) can also be considered as adjuncts for identifying vascular supply to the lower extremity and perforator anatomy. Imaging can also identify rare vascular variations of the lower extremity including peronea magna, in which the peroneal artery is the dominant vascular supply to the lower extremity. However, given the rarity of aberrant perforator anatomy to the lower extremity and the fibula osteocutaneous flap, the authors do not routinely obtain preoperative imaging in patients who have palpable dorsalis pedis and posterior tibial pulses in the distal extremity.

The vascular supply to the skin paddle of the osteocutaneous fibula flap is primarily supplied by the cutaneous perforating branches of the peroneal artery. In our previous prospective anatomical study of the fibular flap perforators (Yu et al. 2011), we identified two groups of cutaneous perforators at reliable intervals along the axis between the fibular head and lateral malleolus. The distal group of perforators, notated “A, B, and C,” could be found at 1/2, 2/3, and 3/4 points of the distance between the fibular head and lateral malleolus, respectively. Distal perforators are generally selected for harvest along with the fibula bone to support the skin paddle. A distinct proximal perforator, named perforator P, was also consistently present at the 1/3rd of the distance from the fibular head. Because of the proximal location of the “P” perforator, it is usually not included in the primary distal skin paddle but is often used to support a second proximal skin paddle to reconstruct a through‐and‐through defect. In our study, we found that approximately 96% of distal perforators were septocutaneous perforators from the peroneal system. In rare cases, however, distal perforators may take a musculocutaneous course and originate from the posterior tibial vessels, the tibioperoneal trunk, or the popliteal vessels. In such circumstances, alternative blood supply to the distal fibular skin paddle needs to be established.

The skin paddle of the fibula osteocutaneous flap has been shown to have highly predictable and reliable vascular anatomy. As previously discussed, the distal cutaneous perforators that are generally most useful for performing composite reconstruction are found to be septocutaneous in 96% of cases. When alternative anatomy is encountered, these representative cases can be used as a guide to harvest a skin paddle successfully. In cases where one or more distal perforators are found to traverse a portion of the soleus muscle, we recommend meticulous intramuscular dissection to trace these perforators before dividing them or abandoning the skin paddle as perforators from the peroneal system may at times be musculocutaneous. If there are multiple cutaneous distal perforators, as is often the case, each perforator should be carefully dissected and evaluated individually as each perforator may be supplied by a different vascular system. Our case examples illustrate that when alternative anatomy is encountered and large cutaneous perforators are identified, the reconstructive surgeon can dissect proximally to identify the vascular source. If dissection demonstrates a more proximal vascular source such as the tibioperoneal trunk or the popliteal system, the pedicle often becomes lengthy and sizeable enough to use for microvascular reconstruction as a freestyle perforator flap. If the distal perforators are absent or unsuitable after dissection, the proximal perforator P should be explored. In some cases, as in Case 3 of our series, a proximal perforator location might still be suitable for the intended reconstruction. If the vascular source does not arise from the peroneal system, a freestyle free flap can be harvested using a proximal perforator with minimal additional morbidity, as the lax nature of the proximal lateral leg often allows for primary wound closure. If no suitable perforators are identified, the use of an alternate donor site can be the most reliable option.

As in many of our mandibular reconstruction cases, recipient vessels can be depleted due to previous surgery and radiotherapy. Finding a second set of recipient vessels can be very challenging. Although we generally prefer a second set of recipient vessels or using a branch of the vascular pedicle of the first free flap as a “parallel” connection for more reliable inflow, a flow‐through or serial connection to the distal end of the peroneal vessels of the fibular flap remains a good option since the caliber and flow are usually appropriate as demonstrated in Case #1.

The skin paddle of the fibula osteocutaneous flap has a highly reliable vascular anatomy; however, variations can occur. Knowledge of variations in vascular anatomy and management strategies can equip the reconstructive surgeon to adapt to challenging cases when they arise. By carefully dissecting and evaluating each perforator, identifying the vascular source, and considering alternative approaches such as flow‐through flaps or freestyle perforator flaps, the reconstructive surgeon can successfully utilize the skin paddle in the presence of alternate vessel anatomy. Through a thorough understanding of the vascular anatomy and a flexible approach to flap design, the reconstructive surgeon can optimize outcomes in fibula flap surgery, even in the face of challenging vascular variations.

Funding

The authors have nothing to report.

Ethics Statement

IRB exemption was obtained to conduct this study.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.