Chimeric Free Fibula Flap: An Encounter With Aberrant Anatomy

Fibular free flap with proximal perforator skin paddle due to aberrant anatomy - a case report

BACKGROUND

The fibular free flap is considered one of the most valuable options for mandible reconstruction. A perforator flap has gained widespread acceptance in oral and maxillofacial reconstruction. Typically, the fibula flap is obtained primarily with the distal perforator due to its reliable blood supply, with less attention given to the proximal perforators during the harvesting process. Normally, the distal perforator of the fibula exhibits stability and shows limited anatomical variations. However, there have been reported cases in which the distal perforator is absent. At times, these vascular abnormalities remain undetectable through Doppler examination or preoperative angiography evaluation. Therefore, this case details the experience of encountering the rare event of vascular abnormality in oral cancer surgery.

CASE PRESENTATION

This article reports the case of a patient who presented with a congenital absence of the distal perforator in the peroneal artery, attributed to a vascular abnormality. Additionally, we provide a review of the concept of utilizing the proximal perforator as an alternative approach in the flap harvesting process.

CONCLUSIONS

While the distal perforator of the peroneal artery is typically utilized for fibula free flap procedures, surgeons must remain cognizant of the potential for its absence due to aberrant anatomy. Recognizing an alternative approach in such cases can be pivotal for precise surgical planning and favorable outcomes in oral and maxillofacial reconstruction.

Proximal peroneal perforator flap, cadaveric study, and clinical applications for shallow defect reconstructions

PURPOSE

Peroneal artery perforator offers a versatile range of microvascular tissue transfer methods from local flaps to vascularized osteocutaneous fibula flaps. It is one of the few flaps that can cover shallow defects that require thin and pliable skin paddles, such as in hands and feet (Han et al., 2018). The proximal region of the lower leg offers such flexible and thin flap compared to the middle and distal lower leg (Winters & de Jongh, 1999). However, the anatomy of the proximal peroneal artery perforator is relatively unknown in literature and its proximity to the common peroneal nerve (CPN) has not yet been studied. This study conducted a cadaveric study and put it in application into clinical settings.

METHODS

Twenty lower leg specimens were dissected according to the methods of clinical proximal peroneal artery perforator flap harvest. Perforators arising in the proximal lower leg area of between 20 and 40 percentile of fibular length were inspected. Perforator length, location from fibular head, course, and location of CPN were recorded. Clinical reconstruction cases using the proximal lateral lower leg were analyzed. Six patients between the ages of thirty and seventy were included. Five cases were due to trauma, and one from mass excision, but all required thin and pliable flaps for reconstructions in hands or feet. Flaps were designed concentrical oval shapes, and harvest was done similarly to cadaveric perforator dissection, but perforator dissection was done only up to the required pedicle length. Perforator length, flap size, thickness, and long-term complications were recorded.

RESULTS

Among 20 specimens, a total of 20 perforators were found in 18 cadavers (90%). Two specimens showed no perforators while two specimens showed multiple perforators. The perforators were located at an average of 101 mm from fibular head, with an average length of 55 mm ranging from 20 to 153 mm. The average size of perforator at origin was 2.0 mm, ranging from 1.0 to 3.6 mm. 45% showed septocutaneous course and 55% intramuscular course. Two out of 20 perforators were shown to arise from source vessels other than the peroneal artery. All clinical cases were successful without complications or debulking for contour shaping. Flap sizes ranged from 15 to 40 cm² . Largest flap width was 5 cm, and all donor sites were primarily closed without complications. One year of follow-up showed no complications.

CONCLUSION

Proximal peroneal artery perforator flap provides a reliable pedicle for a versatile tissue transfer. This study shows that the perforators of the proximal lateral lower leg often arise from vessels other than the peroneal artery, such as the anterior tibial artery or popliteal artery, as had been previously reported (Winters & de Jongh, 1999). Although the source vessel varies, perforator anatomy is at a safe distance from CPN. This variation of source vessels suggests a change in nomenclature to "proximal peroneal perforator flap." The clinical applications of this flap showed that it can be effectively used for reconstructions of shallow defects, such as in the hands and feet without secondary procedures for debulking.

Reconstruction of nasal airway in patients of class IIId maxillary defect with vastus lateralis muscle-chimeric double skin paddle ALT flap

BACKGROUND

A reconstructive challenge in patients with class IIId maxillary defect is how to obliterate the defect and restore a patent nasal airway. The current strategy using the single anterolateral thigh (ALT) fasciocutaneous flap for reconstruction may result in permanent mouth breathing. As the ALT flap was a common option in reconstruction processes, this study aimed to evaluate the benefits of vastus lateralis (VL) muscle-chimeric double skin paddle ALT flap in simultaneous defect and nasal airway reconstruction.

METHODS

This study included 21 patients with class IIId maxillary defect who underwent free ALT flap reconstruction (n = 11, single ALT flap group; n = 10, VL muscle-chimeric double skin paddle ALT flap (chimeric ALT flap) group) at the China Medical University Hospital from August 2015 to September 2019. Associated parameters collected for analysis included gender, age, body mass index (BMI), operative time, hospitalization, clinical stage, preoperative treatment, flap/defect size, comorbidities, postoperative RT, mouth breathing and short/long term complications.

RESULTS

No significant differences were observed in age, BMI, hospitalization, clinical stage, preoperative treatment, defect size, comorbidities, and postoperative RT between the two groups; however, the chimeric ALT flap group as dominated by male patients (p = 0.009), and had longer operative times (12.1 h vs. 10.1 h, p = 0.002) and larger flap sizes (180 cm² vs. 96.7 cm², p = 0.013). Compared with the chimeric ALT flap group, the single ALT flap group suffered from permanent mouth breathing.

CONCLUSION

Nasal airway reconstruction should be considered in patients with class IIId maxillary defect. Compared to the single ALT flap, the chimeric ALT flap is a superior reconstructive option for patients with class IIId maxillary defect, although a longer surgical duration and larger flap size are required.