The blood supply of the reverse temporalis muscle flap: anatomic study and clinical implications

Description of the Pedicled Osteo-Muscular Flap of Split Temporal Muscle

Background

Reconstruction of the head and neck is dominated by free flaps, and for bone reconstruction by fibula and scapula flaps. However, this choice is sometimes difficult to make in patients who cannot tolerate an extensive and lengthy surgical procedure. In addition, vascular micro-anastomoses are sometimes complicated in patients who have been previously irradiated. Pedicle flaps remain an option and can sometimes be considered as first choice for head and neck reconstruction.

Purpose

In this study, we describe the feasibility of a split temporal muscle pedicled flap with coronal harvesting for a reconstruction that can reach the midline.

Study design sample covariates

Ten fresh-frozen human cadaver heads were dissected, and the length of the split flap was noted, followed by the length of the non-split flap.

Results

The mean length was 155.7 mm (± 20.0) for the split flap, from the point of rotation to the tip of the coronoid process. These results coincide with the tragus-midline distance, which makes it possible to consider reconstruction of the midline, especially the maxilla and the mandible, which has not yet been described in the literature.

Conclusions and relevance

This technique would then allow a supply of pedicled vascularized bone for loco-regional reconstruction.

Split temporalis muscle flap anatomy, vascularization and clinical applications

INTRODUCTION

For more than a century, the temporalis muscle has been used for facial reconstructions. More recently, a split temporalis muscle flap elevated on the superficial temporal pedicle has been described, for which the resulting gain of length makes crossing of the midline possible, as well as reconstruction of substance losses exceeding the midline.

MATERIALS AND METHODS

Fourteen fresh cadaveric dissections were performed to study the different techniques for splitting the temporalis muscle. Dissections with catheterization and injection of radio-opaque contrasting agent in the external carotid artery were then performed to specify the vascularization of the flap split on the superficial temporal pedicle.

RESULTS

The duplication of the superficial temporal pedicle grants greater length compared to that of the deep pedicles, 57 mm versus 40 (p = 0.036). The middle temporal artery is capable of ensuring the vascularization, and therefore the viability, of the split flap. From these results, we spoke about the limitations of this study and we have inferred the main indications.

Anterior cranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graft

Background

Cranial base defects are challenging to reconstruct without serious complications. Although free tissue transfer has been used widely and efficiently, it still has the limitation of requiring a long operation time along with the burden of microanastomosis and donor site morbidity. We propose using a reverse temporalis muscle flap and calvarial bone graft as an alternative option to a free flap for anterior cranial base reconstruction.

Methods

Between April 2009 and February 2012, cranial base reconstructions using an autologous calvarial split bone graft combined with a reverse temporalis muscle flap were performed in five patients. Medical records were retrospectively analyzed and postoperative computed tomography scans, magnetic resonance imaging, and angiography findings were examined to evaluate graft survival and flap viability.

Results

The mean follow-up period was 11.8 months and the mean operation time for reconstruction was 8.4±3.36 hours. The defects involved the anterior cranial base, including the orbital roof and the frontal and ethmoidal sinus. All reconstructions were successful. Viable flap vascularity and bone survival were observed. There were no serious complications except for acceptable donor site depressions, which were easily corrected with minor procedures.

Conclusions

The reverse temporalis muscle flap could provide sufficient bulkiness to fill dead space and sufficient vascularity to endure infection. The calvarial bone graft provides a rigid framework, which is critical for maintaining the cranial base structure. Combined anterior cranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graft could be a viable alternative to free tissue transfer.

Reconstruction techniques in skull base surgery

One of the major challenges of cranial base surgery is reconstruction of basal dural defects. Ineffective reconstruction may result in potentially life-threatening complications such as cerebrospinal fluid leak, meningitis, and tension pneumocephalus. Goals of reconstructive procedures are to repair the dural defect and to separate intracranial contents from bacteria-laden secretion of the mouth, nose, and sinus. Different reconstructive techniques have been reported. Multiple factors may influence the surgical choice of reconstructive technique and its outcome. Regional pedicled flap and vascular free flaps represent the best reconstructive options because vascularized tissues promote fast and complete healing. A variety of endoscopic pedicled mucosal flaps within the nasal cavity have also been described. The different reconstruction techniques are described and discussed in terms of indications, advantages, and drawbacks.

The versatile use of temporoparietal fascial flap

BACKGROUND

The pedicled or free temporoparietal fascial has been used in many areas, especially in head and neck reconstruction. This thin, pliable, highly vascularized flap may be also transferred as a carrier of subjacent bone or overlying skin.

OBJECTIVE

The aim of this study is to report our experience in versatile use of temporoparietal fascial flap (TPFF) and discuss the surgical anatomy and technique.

PATIENTS AND METHODS

A total number of 57 TPFFs have been used in periorbital, mid-facial, auricular, and tracheal reconstruction due to tumor resection, trauma, and congenital ear deformities.

RESULTS

All the flaps were successfully transferred without any major complication. The cosmetic results were quite satisfactory to all patients.

CONCLUSION

The advantages and minimal donor site morbidity of TPPF makes this flap a good choice in many reconstructive procedures.

Titanium mesh reconstruction to maintain scalp contour after temporalis musculofascial flap reconstruction of the floor of the middle cranial fossa: a technical note and report of two cases

OBJECTIVE

Temporalis musculofascial rotational flaps can provide excellent tissue for reconstruction of defects in the floor of the middle cranial fossa. This technique can, however, result in cosmetic deformity of the temporal fossa with an asymmetric contour of the head. We report a technique that uses titanium mesh and autologous abdominal adipose to maintain a normal scalp contour.

CLINICAL PRESENTATION

Two patients, one with a large middle cranial fossa and infratemporal schwannoma, and another with penetrating trauma secondary to a rifle accident, required surgical repair of defects of the floor of the middle cranial fossa.

INTERVENTION

The repair was achieved in both cases using a temporalis musculofascial rotational flap. Normal contour of the scalp was maintained with titanium mesh and autologous abdominal adipose reconstruction.

CONCLUSION

The temporalis musculofascial flap, combined with titanium mesh and autologous adipose reconstruction, provided excellent closure of defects of the floor of the middle cranial fossa while preserving normal cosmetic scalp contour.

The temporalis: blood supply and innervation

Numerous reports have described the use of the temporalis muscle as a pedicled flap in reconstructive surgery. A detailed knowledge of the supplying vessels and nerves is necessary for functionally successful muscle transposition. However, controversial anatomic descriptions exist. In this study, 60 human cadavers were investigated to identify the arteries and nerves supplying the temporalis. Forty-three cadavers were dissected after embalming with 10% phenol/formaldehyde. An additional 10 cadavers were examined after injecting latex/barium sulfate (ratio, 1:1) to show the parts of the temporalis supplied by each artery using radiography. The innervating motor branches of the trigeminal nerve were identified by the Karnovsky technique in seven fresh cadavers. In all specimens, three arteries supplying the temporalis were identified: the anterior deep temporal artery (anterior part, 30 percent muscle mass), the posterior deep temporal artery (central part, 51 percent muscle mass), and the medial temporal artery (occipital and in 25 percent upper part, 19 percent muscle mass). Motor branches of the trigeminal nerve innervated the temporalis: the deep temporal nerves of the mandibular nerve (98 percent, central part), branches of the buccal nerve (95 percent, anterior part), and branches of the masseteric nerve (69 percent, posterior part). A remarkable variation of innervating nerve branches, and in 12 percent peripheral anastomoses between the motor nerve branches, were observed. The various numbers of innervating nerve branches demonstrate the difficulty of creating innervated or selectively denervated pedicled muscle flaps for reinnervation. Nevertheless, at least two different pedicled flaps using the anterior or central part of the temporalis can be selectively used for reconstructive surgery.

Anchoring the detached temporalis muscle in craniofacial surgery

The temporalis muscle is often detached to enable craniofacial tumour and trauma access surgery. Failure to carefully handle and reattach the muscle often leads to a cosmetic and functional deformity. The authors discuss the principles of elevation of the whole temporal muscle within its surrounding fascia to reduce atrophy. The temporalis muscle is then reattached to its point of origin, using suspensory absorbable sutures attached to 3 mm titanium microscrews placed inferior to the limits of the muscle, to make them non-palpable. The aim is to reduce the postoperative temporal hollowing often seen when these principles are not observed. A series of cases using this technique are reported.