Reconstruction of complex total parotidectomy defects after ablation is always a challenge for surgeons. The surgical technique in reconstructing total parotidectomy defects using an anterolateral thigh (ALT) flap has not been described in detail. This report describes the treatment of a difficult case with a complex total parotidectomy defect. An ALT flap composed of a vascularized motor branch of the femoral nerve and a narrow portion of the vastus lateralis muscle was harvested. An 8-cm-long vascularized nerve was transplanted into the gap, which can be considered a cable transplant graft, and a myocutaneous paddle was used to cover and fill in the soft tissue defect. There were no complications after surgery, and the patient was satisfied with the reconstructed facial contours. This case shows that using a chimeric ALT flap for reconstruction is possible in a complex total parotidectomy defect.
Reconstruction of complex total parotidectomy defects after ablation is always a challenge for surgeons. A nerve graft made of the great auricular nerve or the sural nerve is helpful when there is a gap between the distal and proximal stumps of a facial nerve that has been severed. However, a poorly vascularized bed is often the recipient site of a graft after resection of a malignant parotid gland tumor, because of bone exposure, skin loss, radiotherapy effects, and scar formation. When free nerve grafts are necessary, nerve regeneration can be affected as a result of these problems. Some experimental and clinical reports have shown that vascularized nerve grafts can be advantageous for nerve graft survival. Under such conditions, a free vascularized motor branch femoral nerve graft and a chimeric anterolateral thigh (ALT) transplant graft were used to repair a total parotidectomy defect. Song et al described the ALT flap in 1984, and the ALT flap has been used increasingly in head and neck reconstruction surgery. Elliott et al reported on their experiences in reconstructing total parotidectomy defects using ALT flaps; however, the surgical technique was not described in detail. In this case report, the authors describe their experience with the surgical techniques used to reconstruct a combination facial nerve and soft tissue defect after removal of a parotid gland carcinoma and assess the function of the donor sites.
Report of Case
A 43-year-old man with recurrent acinic cell carcinoma of the left parotid gland was referred to the authors' department. The patient's medical record was carefully reviewed. According to the surgical notes, the primary tumor was located inferior to the left parotid gland. He had undergone partial superficial parotidectomy for the left parotid tumor, including the inferior and middle parts of the superficial lobe, and received postoperative radiotherapy, with an average radiation dosage of 50 Gy, 2 years previously. The recurrent tumor involved the deep lobe of the parotid gland, the facial skin, and the facial nerve ( Fig 1 ); however, there was no preoperative facial paralysis. A nerve graft that was vascularized to reconstruct the facial nerve defect was used to maintain function.
Wide resection was performed of the affected area of the parotid gland that included the overlying skin. A selective neck dissection (levels I to III) was performed on the left side. The excised lymph nodes were submitted to the pathology department, in particular 2 suspicious lymph nodes in the superior deep cervical region (level IIB). All branches of the facial nerve were identified and marked. The tumor invaded partial paths of the temporofacial and cervicofacial branches and trapped the buccal branches and marginal mandibular branch. The involved facial nerves were degraded and difficult to detach ( Fig 2 ). Therefore, the involved nerve trunk and all of its branches were incised. The results of histopathologic examination ( Fig 3 ) showed that the acinar type cells compromising the tumor (black arrow) infiltrated near the facial nerve (red arrows). After tumor resection, the margins were proved negative. There was an 8-cm-long gap from the proximal end to the distal end of the facial nerve ( Fig 4 ).
An ALT flap was harvested simultaneously with the parotidectomy and neck dissection. The free chimeric ALT flap, which was 10 × 5 cm, included a thin portion of the vastus lateralis and vascularized motor branch of the femoral nerve. This flap was elevated based on the descending branch of the lateral circumflex femoral system ( Fig 5 ). The method of harvesting an ALT flap is well documented. In this report, only the technique used for harvesting additional tissue is described. Because the muscular components offer more degrees of freedom for inset, muscular components were preferred based on the distal runoff of the lateral femoral circumflex vessels (LFCVs). At least 1 sizable muscular perforator originating from the LFCVs was chosen to elevate the muscular portion of the chimeric flap. Also, a portion of the vastus lateralis was chosen randomly, as needed, to cover the defect. An 8-cm-long vascularized motor branch of the femoral nerve that accompanied the descending branch of the LFCVs was simultaneously obtained to interpose the nerve gap. The distal section of the vascularized lateral femoral nerve was divided into 3 portions and each portion was sutured to the distal facial nerves that were resected. Then, the proximal portion was sutured to the facial nerve stump. Before reconstruction of each branch of the facial nerves that had been resected, microvascular anastomosis of the transferred flap was performed. The marginal mandibular and buccal branches of the facial nerve that were severed were reconstructed using sections of the motor branch of the femoral nerve. New bleeding at each end of the grafted vascularized nerves was observed. The residual temporofacial trunk was anastomosed to the facial nerve trunk. The donor site was closed primarily.
The postoperative pathologic analysis confirmed that there was no cervical lymph node metastasis. No complications were observed at the donor or recipient site and the postoperative course was normal. The patient started walking 3 days postoperatively. Isokinetic dynamometer measurements of quadriceps muscle eccentric and concentric strengths were performed before the operation and 3 and 6 months after surgery. There was a 25% deficiency at 3 months after surgery in the isokinetic concentric peak torque per weight, with total and maximum work of the quadriceps at a 90° angular velocity per second. However, all these values returned to 90% of preoperative levels of the donor site 6 months after the operation ( Fig 6 ). The patient sensed no disturbance when walking or playing sports, and he perceived no pain or palsy except for a small amount of numbness at the donor site 6 months postoperatively.
The patient underwent radiotherapy 50 Gy 1 month after surgery. The re-innervated nerve began to recover 3.5 months after surgery. Nearly normal motion was recovered at 6 months after surgery, except for the corner of the mouth. The contours of the face were normal after reconstruction and the patient indicated satisfaction with the results ( Figs 7, 8 ). There was no major subjective donor-site problem except for scarring. The patient indicated normal daily activities were performed without difficulty after 6 months of vigorous postoperative rehabilitation. During the first 3 years of follow-up, the patient was advised to visit the clinic at intervals of 3 months postoperatively. During this period, the patient also underwent routine chest radiography and liver ultrasound to rule out distant metastasis. After 3 years, the recommended follow-up was changed to 6-month intervals.
A facial nerve grading system was used to assess functional recovery. The House-Brackmann system was assessed as grade II.
Reliable reconstruction of the facial nerve, augmentation of the defect using similar tissues, and no facial contour deformities are the main goals of complex total parotidectomy after resection of a parotid carcinoma.
A flap with adequate bulk is required for normal contour reconstruction, including missing skin, for preauricular, retromandibular, and superior cervical soft tissue loss resulting from total parotidectomy. Use of a free ALT flap for total parotidectomy reconstruction has been suggested in several studies based on clinical approaches. An ALT flap was chosen because its superior versatility in a reconstruction procedure allowed precise customization for the patient and it facilitated harvesting a vascularized nerve and a thin portion of the vastus lateralis at the same donor site.
Taylor and Ham designed the vascularized nerve graft in 1976. The advantages of this approach are avoidance of an initial period of ischemia and guaranteed nutrition of the graft. Previously, experimental and clinical studies reported substantially better regeneration of nerves when the nerve grafts were vascularized compared with conventional free nerve grafts. Nerve grafts that are vascularized have 2 major advantages, namely an increased number of large, myelinated axons and rapid axonal regeneration. Therefore, free vascularized nerve grafts were used for facial nerve reconstruction, which improved the status of the recipient bed. There are many factors than can influence functional recovery, such as pre- or postoperative radiotherapy, the extent of the initial damage and tissue loss, and the extent of vascularization of the bed in which repair will occur. To obtain better functional results, a thin portion of the vastus lateralis muscle of a chimaera ALT flap was used as a recipient bed. Transplantation of a muscle flap also prevents facial contour deformity. In the present case, the postoperative functional results were satisfactory. Therefore, a chimeric ALT perforator flap with a vascularized nerve graft is a good choice for patients who have had previous irradiation treatments.
In the present case, donor-site morbidity was not obvious except for scar and peri-incisional numbness. The patient's mobility was not affected when the motor nerve to the vastus lateralis was used. This result was similar to results reported in previous studies. One study reported less objective morbidity of the donor site when using a small amount of muscle with the motor nerve and a narrow strip of the vascularized fascia lata. The present patient's subjective reports indicated the deficits did not interfere with daily activities. In addition, the facial nerve returned to normal in the following order: temporal and zygomatic branches (3 months), buccal branches (6 months), and marginal mandibular branch. There was no neurotization in the marginal mandibular branch at 7.5 months postoperatively. Because the marginal mandibular branch has a small diameter compared with other branches, it is less likely to recover. The authors believe the zygomatic and buccal branches are functionally more important than the others, thereby making the results acceptable.
The technique used for this patient was a refinement of an ALT flap procedure and can offer additional advantages: 1) avoidance of a contour deformity with a chimeric ALT flap; 2) shorter operative time because the chimeric ALT flap procedure is minimal compared with the time needed for a single ALT flap transfer; 3) a chimeric ALT flap can offer more degrees of freedom and meets the demands of a 3-dimensional defect ; 4) a chimeric ALT flap can supply a vascularized nerve graft and recipient bed; and 5) a vascularized motor branch of the femoral nerve can be harvested easily and can be split for complete facial nerve reconstruction.
A chimeric ALT flap with a vascularized motor branch of the femoral nerve is an alternative for a complex total parotidectomy defect reconstruction, especially for a scarred recipient bed.