Chimeric superficial temporal artery based skin and temporal fascia flap plus temporalis muscle flap - An alternative to free flap for suprastructure maxillectomy with external skin defect.

Flaps from temporal region have been used for mid face, orbital and peri-orbital reconstruction. The knowledge of the vascular anatomy of the region helps to dissect and harvest the muscle/fascia/skin/combined tissue flaps from that region depending upon the requirement. Suprastructure maxillectomy defects are usually covered with free flaps to fill the cavity. Here we report an innovative idea in which a patient with a supra structure maxillectomy with external skin defect was covered with chimeric flap based on the parietal and frontal branches of superficial temporal artery and the temporalis muscle flap based on deep temporal artery.

INTRODUCTION

Temporal region is a source of flaps of different tissue quality. Flaps can be raised individually/combined fashion depending upon the requirements. Maxillectomy defects require bulky and pliable tissue for reconstruction to fill the cavity and maintain the facial contour. This is usually accomplished with free flaps- an ALT/rectus flap. The following description is the application of temporal region flaps with forehead flap in a case of cancer maxilla for which suprastructure maxillectomy with skin excision was performed. The case is presented to highlight the management of complex defect with combination of loco regional flaps and its innovative application.

CASE REPORT

This 42-year-old male was diagnosed as right-sided Ca maxilla. He was evaluated and suprastructure maxillectomy (antrum, orbital floor), part of Zygoma with skin excision of 5 × 2 cm was performed by the oncosurgeons [Figures 1 and 2].

Figure 1

Skin defect

Figure 2

Maxillary defect

Initially the patient was planned for free ALT flap. Intraoperatively, we made an alternative plan, because the required skin and soft tissue was relatively less. The right STA pulsations were confirmed. The reconstruction needs to address the orbital floor, filler for cavity and external skin cover. We planned titanium mesh for orbital floor, temporalis muscle and fascial flap for the cavity and an islanded forehead flap for the skin defect.

The markings were done as shown in Figure 3. A gentle “C” shaped incision was made in the R temporal region. Skin was raised in the sub-dermal plane. The temporoparietal fascia along with deep temporal fascia was dissected as a single unit based on the parietal branch of STA, up to the zygomatic arch. This fascial flap was harvested with about 5 cm of pericranium in the distal end to add bulk. Then the temporalis muscle was dissected based on the deep temporal arteries. Next the planned forehead skin flap based on the frontal branch of the STA was elevated [Figure 4]. The frontal branch of the facial nerve was identified and preserved. The orbital floor was reconstructed with titanium mesh [Figure 5]. First the fascial flap was transposed into the defect over the zygomatic arch. It was used to cover the titanium mesh and was sutured to the surrounding soft tissues [Figure 6]. The temporalis muscle was passed through the defect in the anterior part of the zygomatic arch, created by the oncosurgeon during excision. This further aided in the reach of the flap and used as filler in the maxillary antral region. Finally the forehead flap was used to cover the skin defect [Figure 7]. The temporal incision was closed primarily. Attempted closure of the forehead donor site caused elevation of the right eyebrow and hence the secondary defect was covered with STSG from scalp. The flap and donor site healed well without any complications. Comparison of the pre-operative and post-op pictures at three months follow up showed an aesthetically pleasing and harmonius facial contour [Figures 8–10].

Figure 3

Pre-operative planning

Figure 4

All 3 flaps elevated

Figure 5

Orbital floor reconstructed with titanium mesh

Figure 6

Temporoparietal fascia + deep temporal fascia covering the titanium mesh

Figure 7

Immediate post-operative status

Figure 8

Pre-operative worm's eye view

Figure 10

Post-operative frontal view

Post-operative worm's eye view

DISCUSSION

The arterial anatomy and the vascular basis of various temporal flaps were described by H. Nakajima et al.[1] The temporal region has arterial supply network in four tissue layers.

Skin and superficial temporal fascia network

Loose areolar fascia/subgaleal network

Deep temporal fascia network

Temporal muscle network

These vascular networks have good communication with each other. Based on this vascular anatomy, different possible options of combined or individual flaps have been described in this region. Dunham[2] was the first to use the STA as a pedicle flap for reconstruction of facial defects in 1893. Horowitz et al.[3] combined two anatomical structures – galea and pericranium as a single flap in orbital and facial reconstruction. Ozdemir et al.[4] demonstrated the possible options of island skin flaps based on the frontal and parietal branches of the STA in the reconstruction of various facial defects. Harun et al.[5] has designed the bilobed STA flap based on the frontal branch for defects involving lateral canthus, upper and lower eyelids.

Obliteration of the cavities in skull base and midface has been a problem with locoregional flaps because of the lack of adequate, bulky vascularised tissue. Joseph et al.[6] described temporoparietal fascia flap as “work horse from above” for head and neck reconstruction. Andrew et al.[7] used the pedicled temporoparietal fascia for the suprastructure maxillary defect. But the fascia alone may not be adequate enough to fill the cavity. The pedicled temporal flaps can be a good alternative in such conditions. The muscle and the fascial flap add bulk and also provide a well vascularised tissue withstanding radiation.

In the present case, the orbital floor was reconstructed with titanium mesh. It is simple, easy to apply and also CT/MRI friendly. Calvarial bone grafts with temporoparietal fascia would have been difficult to contour. The temporoparietal fascia with deep temporal fascia was used to cover the mesh, the temporalis muscle was used to fill the maxillary cavity. Separation of the fascial layer and the muscle also helps in the increased mobilisation and reach of either of the tissues. The forehead skin was used for skin cover with good colour match. The facial contour was good with the eyeball in normal position and no post operative diplopia. The grafted forehead donor site healed well and remained hidden under the hair line. The contour deformity in the temporal region was camouflaged after hair growth. Moreover, the technical difficulties, time taken and financial restraints of a free flap were all avoided.

The temporal region is a good donor site because of rich vascular network and availability of different tissues-skin, fascia, muscle, galea, calvarial bone and pericranium. Thus, one or more tissues can be harvested depending upon the defect site and nature. The better understanding of the surgical anatomy of this region offers us a suitable alternative to free flaps for suprastructure maxillary defects.