Reconstruction of the Tongue after Hemiglossectomy Using Serratus Anterior Muscle Free Flap

Background Serratus anterior muscle free flap is widely used in numerous indicated reconstructions. Only a few studies have dealt with the use of this flap in tongue reconstruction. Materials and Methods We present a case series of 7 patients with carcinoma of the tongue who underwent hemiglossectomy followed by immediate reconstruction with serratus anterior muscle free flap between January 2017 and December 2019 at the University Hospital Brno. The aim of this study was to evaluate safety and efficiency of the reconstruction as well as the donor site morbidity. Results There was not a single case of flap failure observed and the donor site healed completely in all cases. The functional outcome (tongue mobility, phonation, and deglutition) depended on the severity of the primary oncological disease and health status of the patient. Conclusion The serratus anterior muscle free flap represents an alternative option for reconstruction of the tongue.


Introduction
Growing incidence of tongue tumours places higher demands on its reconstruction [1].In order to ensure good functional result and proper tongue function after hemiglossectomy, an adequate volume of the missing mass and shape must be restored.Free fap transfer is the current method of choice in tongue reconstruction with radial forearm free fap (RFFF) and anterolateral thigh free fap (ALTFF) considered as workhorses [2].
Te serratus anterior muscle free fap (SAMFF) provides a thin and pliable muscle tissue, which is easy to harvest and has long vascular pedicle of good calibre.Tere are only some cases of tongue reconstruction with SAMFF described in the literature despite its advantages.
In this case series, we evaluated tongue reconstruction using SAMFF in 7 patients who underwent hemiglossectomy at the University Hospital Brno.Te aim of the study was to evaluate safety and efciency of the reconstruction, functional result of the restored tongue, eventual complications of wound healing, or fap failure and donor site morbidity.

Case Series
We present a case series of 7 patients who underwent hemiglossectomy for various carcinomas of the tongue between January 2017 and December 2019 at the University Hospital Brno.Inclusion criteria were surgical resectability of the tumour and the need of free fap reconstruction.Te surgical resection was followed by an immediate reconstruction of the tongue with muscle fap SAMFF in all the patients (no myocutaneous form was performed).Te radical tumour resection with or without laryngeal preservation, alongside with deep cervical lymphadenectomy for an advanced stage of invasive tumour, was performed by otolaryngologists, and the immediate reconstruction using SAMFF was performed by plastic surgeons as a one stage  procedure.Te design of the fap was adapted to the missing volume and shape, and an oval shape was used in all cases.
Te fap was spread and modelled at the site of the missing tissue to achieve maximum symmetry with the unafected side of the tongue.Tere were 5 female and 2 male patients in the series with the average age of 63.8 years (48-82 years).Following parameters were assessed: age, sex, tumour characteristics, histopathological classifcation, complications in healing, and fap failure (Table 1).Functional outcomes such as phonation and oropharyngeal dysphagia evaluated by fexible endoscopic evaluation of swallowing (FEES) were followed by an attending ENT surgeon.Morbidity of donor site (pain, scar, and shoulder mobility) was evaluated by an attending plastic surgeon.
Tere was not a single case of fap loss observed in the postoperative period.Tere were only minor complications in wound healing in two cases of the reconstructed tongue which were treated conservatively.Te healing of the faps in the oral cavity was not accompanied by any complications despite the exposure of saliva, and a very good aesthetic result was achieved after the resolution of the swelling and the maturation of the tissues.Te functional outcome of the reconstructed tongue (Figure 1) depended on the severity of the primary oncological disease and the health status of the patient.Te donor site healed completely in all cases, and no functional disorders of the upper extremity movement were observed (Figure 2).In majority of patients, the results of the tongue mobility, phonation, and deglutination were evaluated as adequate.

Discussion
Free fap transfer represents a method of choice in tongue reconstruction after hemiglossectomy.Fasciocutaneous and perforator free faps such as RFFF and ALTFF are the method of choice.Muscle free faps, such as rectus abdominis muscle free fap [3,4], vastus lateralis myofascial free fap [5], or gracilis muscle free fap [6], are used rather rarely.Te myocutaneous form of SAMFF was used by Janik et al. for reconstruction in 7 patients who underwent salvage glossectomy [7].
SAMFF in general is a highly reliable fap with excellent anatomical characteristics for free fap reconstruction of small and moderate defects.It is easy to harvest and wellsuited for head and neck reconstruction.
Te main disadvantages of this technique include the impossibility to use the two-team approach and donor site morbidity with the loss of the muscle tissue.In our study, we did not observe any problems with the upper extremity function, wound healing, or resulting scar in the postoperative follow-up.Te scar was well accepted by the patients.Second, it is not possible to assess directly the fap perfusion of MSAFF by capillary refll, as it can be performed in case of fasciocutaneous or perforator faps.On the other hand, capillary refll assessment of fasciocutaneous or perforator faps used on reconstruction of deeply localized defects of tongue base is compromised by perioperative and postoperative swelling.Standard examination of muscle fap is performed by the Doppler probe, which identifes vascular pedicle pulsation.Te microsutures are often performed on recipient neck vessels.Terefore, high interference from surrounding vessels prevents detection of vascular pedicle of muscle fap by dopplerometry.

Conclusion
Te SAMFF represents an alternative option for tongue reconstruction after hemiglossectomy.Te main advantage of this fap is muscle-to-muscle connection, natural look of the reconstructed tongue, and easy harvesting of the fap with low donor site morbidity.

Data Availability
No data were used in this study.

Figure 2 :
Figure 2: Low donor site morbidity after harvesting MSAFF, 26 months after the surgery.

Table 1 :
Study participants, surgical treatment, and functional outcomes.