Sternocleidomastoid Myocutaneous Flap for Scalp Reconstruction

Abstract

Scalp defects may occur due to various causes, such as head trauma. For reconstruction of the defect, a primary closure process, skin grafting, or local flap use are the foremost choices when the defect area is not wide. However, repair is difficult when the wound condition further deteriorates due to chronic inflammation. In this condition, free tissue transfer or a pedicled flap is required to restore normal blood supply. The sternocleidomastoid (SCM) flap is conventionally raised as a superiorly or inferiorly based pedicled flap, easily harvested to rectify a nearby scalp defect; additionally, it may either be muscular or myocutaneous. This report describes a case of successful use of the SCM flap for scalp reconstruction, raised as a superiorly based myocutaneous flap.

Introduction

Scalp defects may occur due to various causes, such as head trauma. When the defect is not wide, we select a primary closure process, skin grafting, or local advanced flap for reconstruction. However, for wounds associated with chronic inflammation due to infection, reconstruction of defects is difficult. In such conditions, normal blood supply is required to restore the scalp. Free tissue grafts, such as a free forearm flap, pedicled myocutaneous flap, or trapezius myocutaneous flap, may repair such scalp defects. Additionally, we propose a pedicled flap, the sternocleidomastoid (SCM) flap, which is conventionally raised as a superiorly or inferiorly based pedicled flap that may either be muscular or myocutaneous. ^1,2 Moreover, the SCM flap is easily harvested from a nearby scalp area for reconstruction.

Case Report

A 25-year-old man who was involved in a motorcycle traffic accident subsequently underwent surgery for intracranial hematoma removal. After the surgery, a scalp defect was observed, due to loss of a portion of the scalp skin in the accident (Figure 1). Initially, secondary intent was attempted for this wound; however, the wound did not heal. Subsequently, we attempted to use a local advanced flap, which also proved to be unsuccessful. Indeed, a part of the skull bone at the area of the scalp defect was removed at the time of surgery for the decompression of intracranial pressure. Therefore, we decided to use an SCM flap for the reconstruction of this defect, in order to restore normal blood supply. In the operating room, the patient was placed in a supine position, with the neck extended and skin exposed from the scalp defect to the clavicle. We then designed the skin paddle along the anteroinferior aspect at the middle one-third of the SCM muscle. The myocutaneous flap was elevated off the investing cervical fascia. During this procedure, we carefully preserved the branches of the occipital artery, which predominantly supplies blood to the SMC muscle superiorly. Subsequently, we rotated the myocutaneous flap, avoiding the twisting of the occipital artery branches (Figure 2). The skin margins were sutured without tension at the scalp defect. After the surgery, dressing of the wound was carried out twice per day to prevent secondary infection. At 1 month after the operation, the patient was discharged with a well-implanted SCM flap (Figure 3).

Figure 1.

Preoperative scalp defect.

Figure 2.

A and B, Raised sternocleidomastoid (SCM) flap during surgery.

Figure 3.

Well-implanted sternocleidomastoid (SCM) flap at 1 month (A) and 3 months (B) after surgery.

Partial skin loss was apparent during the early phase, which was re-epithelialized within 3 weeks. There were no other complications, such as flat neck deformity or torticollis.

Discussion

An SCM flap is conventionally raised as a superiorly or inferiorly based pedicled flap; the reported alternatives are myocutaneous, muscular, myoperiosteal, and osteomuscular flaps. ^1,2 The use of the SCM flap is widely accepted in the prevention of Frey syndrome for parotid surgery, closing of the orocutaneous fistulae, and reconstruction of the tongue, mouth floor, and buccal mucosa.

The SCM flap is a type II flap with a segmental vascular supply. Kierner et al divided the vascular pattern of the muscle into 3 horizontal parts: upper, middle, and lower. ³ They described a nourishment pattern consisting of supply to the upper part by the occipital artery, to the middle part by the superior thyroid artery, and to the lower part by the supraclavicular artery. For successful SCM flap reconstruction, Sasaki et al recommended the preservation of the superior thyroid artery. ⁴ However, Larson and Gorpfert believed that the occipital artery was responsible for major blood supply to the SCM muscle. ⁵ Furthermore, Wei et al reported successful outcomes with the use of the occipital artery, rather than the superior thyroid artery. ⁶

In our case, the application of a local flap for reconstruction of the scalp defect was not successful, as previous neurosurgical procedures may have led to unfavorable wound bed conditions. Therefore, we used an SCM flap for reconstruction of the scalp defect. The occipital artery was designated as the major supply artery to increase rotation arc. We used a muscular split paddle, which originated at the sternal head of the SCM muscle, to increase the rotation arc and reduce the bulkiness of the SMC flap. The skin paddle was designed at the middle one-third of the SCM muscle. We determined that perforators from the occipital artery can supply this skin paddle. Despite partial skin necrosis, secondary healing was possible within 1 month.

In general, the SCM flap is useful for reconstruction in the areas of the head and neck, and especially for the oral cavity. However, most of the indications are below the zygomatic arch area, due to limitations of the rotation arc. Therefore, reconstruction of the scalp with an SCM flap is very rare. In our case, we used the occipital artery as a main supplying artery, as well as a split muscle flap for extending the rotation arc. Furthermore, we expect that the application of SCM flaps will increase with the development of a more precise understanding of vascular anatomy.

Conclusion

The SCM flap is a pedicled flap that can be harvested from the nearby scalp. Therefore, we suggest that the SCM flap is an appropriate choice for the reconstruction of poor healing scalp defects.