Introduction

According to a study by Siegel et al. (2014), the United States reports over 42,000 new cases of oral cancer annually, with more than 8,000 deaths each year [1].

In Vietnam, from 2015 to 2019, the National Hospital of Odonto-Stomatology in Hanoi detected 628 cases of tongue and floor-of-mouth cancer among 11,738 patients, with an incidence rate of 5.35%. On average, 125.6 new cases of tongue and floor-of-mouth cancer were diagnosed annually [2].

Most patients present at late stages, requiring wide tumor excision and reconstructive surgery to restore defects in the oral cavity. Various free flaps have been used for tongue and floor-of-mouth reconstruction, including the radial forearm flap, anterolateral thigh flap, gracilis muscle flap, and lateral arm flap. Each flap has its advantages and disadvantages, and the choice of technique depends on the surgeon’s experience [3–6].

In this study, we evaluate the outcomes of using the lateral arm flap for tongue and floor-of-mouth reconstruction in patients undergoing cancer resection over the past five years at Central Military Hospital 108 and National Hospital of Odonto-Stomatology in Hanoi.

Research subject and method

Research subjects: patients diagnosed with oral cancer at various stages who visited and received treatment at 108 Military Central Hospital and National Hospital of Odonto-Stomatology in Hanoi from 2020 to 2024.

Inclusion criteria:

— Patients diagnosed with tongue or floor of mouth cancer with pathological diagnostic.

— No previous surgery or radiotherapy.

— No distant metastases.

— No systemic disease which affected the anesthesia procedures.

— Willing to attend cancer resection and free flap reconstructive surgery

Exclusion criteria:

— Distant metastases.

— Systemic diseases affecting surgical procedures.

— Previous surgery or scar along the lateral arm area.

Research method: Prospective, interventional clinical study with longitudinal follow-up

Patients underwent clinical and paraclinical examinations before surgery, with tumor assessment based on T, N, M classification to determine disease stage. Routine laboratory tests, MRI, and PET/CT scans were performed to evaluate tumor location, size, extent of invasion, and lymph node metastasis. The planned tumor resection area, neck dissection, and required size of the lateral arm flap for oral cavity reconstruction were determined accordingly.

Surgical procedure: Patients underwent surgery under general anesthesia with endotracheal intubation. Two surgical teams operated simultaneously. One team performed neck dissection and tumor resection. The other team harvested the lateral arm flap, following the previously described steps [1, 2].

Outcome evaluation: A surgical outcome assessment was developed based on criteria established by domestic and international authors. Speech function was evaluated using the Speech Intelligibility Test (SIT). Swallowing function was assessed using the 7-point Functional Oral Intake Scale (FOIS) from the United States. Collected data were processed using SPSS Statistics 20.0 software.

Result

Patient characteristics:

— Age: Range 27–77, mean 57.05 (SD=10.074) years old.

— Sex: 46 Male, 15 Female, M/F ratio 3/1.

— Time from diagnosis to surgery: from 0 to 12 months, average 4.9 (SD=3.58) months.

— Staging: Stage II 37/61 patients (60.7%), Stage III 16/61 patients (26.2%), Stage IV 8/61 patients (13.1%)

— Tumor location: oral tongue 52/61 (85.24%), floor of mouth 7/61 (11.5%), tongue base 2/61 (3.3%).

Surgical outcome

In stage II patients, 91.9% underwent unilateral neck dissection, whereas in Stage IV, 100% underwent bilateral neck dissection. The difference was statistically significant (p=0.01).

— Lateral arm flap: Average size: 5.87×14.54 cm.

Average area: 67.99 (SD=11.74) cm².

— Recipient vessels: Ipsilateral superior thyroid artery in 43/61 (70.49%) cases. Ipsilateral facial artery in 18/61 (29.50%) cases.

— Flap survival rates: 60/61 flaps survived, consist 98.36%.

1/61 flap necrosed, consists 1.63%.

— Donor site: Primary closure in 52/61 cases, consists 85.2% with average donor skin area 67.63±12.19 cm².

Split thickness skin graft in 9/61 cases, consists 14.8% with average donor skin area 70.08±8.94 cm². There is no specific correlation between primary closure or skin graft indications and donor skin area (p=0.48).

— Recipient site: Primary healing: 58/61 cases.

Delayed healing: 3/61 cases.

Results of speech function recovery

Speech function gradually improved from the 3rd to the 24th month, with 6.4%, 13.0%, 62.0%, and 86.1% of patients showing improvement. The difference was statistically significant (p=0.01).

Fig. 1. ¹/₂ and full tongue defects.

Fig. 2. Male, 40 years old, tongue carcinoma T2N0M0.

a, b — skin incision for cancer resection, neck dissection, and provisional flap; c–d — neck dissection level I, II, III half tongue and submandibular gland excision; e — tongue reconstruction by lateral arm free fla; f — 3 year follow up.

Fig. 3. Post op and 2 year follow up image of half tongue reconstruction.

Table 1. Neck dissection and staging correlation (n=61)

Table 2. Defects after cancer resection (n=61)

Table 3. Speech function after surgery (n=61)

Table 4. Swallowing function after surgery

Results of swallowing function recovery

Swallowing function gradually improved from the 3rd to the 24th month, with 9.8%, 60.9%, 87.0%, and 90.61% of patients showing improvement. The difference was statistically significant (p=0.01).

Discussion

The lateral arm flap was first described by Song in 1980, but it was not widely used until the 2000s [7, 8]. In 2008, Faria Marquet [9] reported the use of 210 lateral arm flaps for reconstructing soft tissue defects in the head and neck after cancer resection, with 90.9% of cases involving reconstruction of defects following oral cavity cancer resection. The author’s selection criteria for the lateral arm flap were simple: it had an ipsilateral recipient vessel available and the donor site could be closed directly. The lateral arm flap has a moderate size, making it suitable for small and medium-sized defects, and it is easy to harvest. Its vascular pedicle diameter is similar to that of the facial artery and the superior thyroid artery. A major difference between the lateral arm flap and the radial forearm flap is that the donor site scar of the lateral arm flap is more concealed and can be covered by short-sleeved clothing. Due to these advantages, we selected the lateral arm flap as the primary reconstructive material for soft tissue defects following oral cancer resection [7, 9, 10].

The mean patient age in Marquet’s 2008 study was 49.7 years, while Thankappan (2011) [11] reported a mean age of 55.8 (SD=12.2) years, and Pastars [12] reported a mean age of 58 years, with a male-to-female ratio ranging from 2.1:1 to 3:1. In our study, the mean patient age was 57.05 (SD=10.074) years, with a male-to-female ratio of 3:1, and the average time from disease detection to surgery was 4.9 (SD=3.58) months. Oral cancer predominantly occurs in individuals aged 50–70 years, accounting for 80.32% of cases (p=0.0001). These findings are consistent with those of Marquet, Thankappan, and Pastars in terms of age and gender distribution.

Early clinical symptoms of oral cancer are mild and nonspecific, leading to delayed diagnosis. Many patients do not seek medical attention early, and in some cases, doctors fail to detect the disease. Consequently, patients often present at advanced stages, with characteristic symptoms such as palpable masses (76.11%), necrotic ulceration (68.78%), and pain (76.91%). The disease is most commonly diagnosed in Stage II (47.3%) and Stage III (36.9%), while only 4.93% of cases are detected at Stage I.

Tumors are most frequently located in the mobile tongue and the floor of the mouth (88.5%). In Marquet’s study, tumors measuring 1–4 cm accounted for 72.4% of cases, corresponding to Stages I and II, whereas 27.6% of tumors were larger than 4 cm, corresponding to Stages III and IV. Thankappan (2011) reported that 95.8% of patients had T1 or T2 tumors, while Pastars (2018) found that 71% of patients had T3 tumors. These authors classified tumors based on the T staging system, which categorizes tumors as T1 (≤2 cm), T2 (2–4 cm), and T3 (>4 cm). This classification is similar to our study’s staging system.

Determining the location and size of the tumor is crucial in deciding the resection margins and the size and composition of the lateral arm flap required for reconstruction. Tumor location is typically assessed through clinical examination, but evaluating tumor depth and invasion requires imaging studies such as MRI and PET/CT scans to guide surgical resection. Most authors agree that a clear surgical margin should be 1.5 to 2 cm from the tumor [13–16]. In Marquet’s study of 169 patients with oral cancer, the extent of resection included:18.34% underwent hemiglossectomy with floor of mouth resection, 9.46% had three-quarter glossectomy, 3.55% had a total glossectomy extending to the oropharynx, 24.85% underwent posterior mandibular resection, 16.56% had floor of mouth resection, and 7.10% had buccal mucosa tumor resection. In our study, the resection extent included: ¹/₃ to ¹/₂ of the tongue in 8.18% and 62.29% of cases, respectively, ²/₃ of the tongue and floor of the mouth in 29.50% of cases. Compared to Marquet’s study, our results differ due to a smaller patient sample and a higher proportion of tongue cancer cases. In contrast, Marquet’s study had a more balanced distribution of cancers affecting the tongue, floor of the mouth, posterior mandible, and buccal mucosa.

Simultaneously with the neck dissection and tumor resection, the lateral arm flap harvest is performed concurrently. The flap is typically harvested from the lateral lower third of the arm, but in recent years, many authors have opted for harvesting from the upper third of the forearm. In Marquet’s study, 95.7% of lateral arm flaps were extended flaps. According to the author, the fasciocutaneous flap from the upper third of the forearm is thinner, making it more suitable for reconstructing areas such as the cheek, posterior mandible, and particularly the mobile tongue, as it prevents excessive thickness in these regions. Depending on the defect size, authors have used flaps ranging in size from 4×2 cm to 17×8 cm, with an average of 5.8×4.6 cm [6, 10] or a mean area of 44 cm² [9]. In our study, the average flap size was 5.87×14.54 cm, with a mean area of 67.99 (SD=11.74) cm². This flap size is comparable to Marquet’s study but larger than the flaps used by Thankappan and Song. The difference is likely due to the fact that in their studies, 72.4% of patients had tumors smaller than 4 cm, resulting in smaller post-resection defects and thus requiring smaller flap sizes.

The recipient vessel selection depends on the experience and preference of each surgeon, so the choice of recipient vessel may vary. However, in 16 patients who underwent flap grafting for oral cavity reconstruction after tumor resection, 15 (93.75%) flaps were anastomosed with the facial artery, and only once (6.25%) was the superior thyroid artery used. Thankappan used the superior thyroid artery in 83.3% of cases and the facial artery in 16.7%, while Pastars used the superior thyroid artery in 32% and the facial artery in 68%. In our study, the superior thyroid artery on the same side was used in 43/61 (70.49%) cases, and the facial artery on the same side in 18/61 (29.50%) cases. The differences between authors are inevitable, but the crucial factor is the success of the flap survival. Today, microsurgical techniques have become routine in modern surgery, so the success rate of vessel anastomosis is very high, ranging from 95% to 100%. The success rate in our study was similar, with a 98.36% success rate. One case of vascular necrosis occurred on the second day after surgery, and the flap had to be removed. For flap donor sites: 52/61 cases had direct skin closure, accounting for 85.2% of cases, with an average skin area harvested of 67.63±12.19 cm². 9/61 cases required split-thickness skin grafting, accounting for 14.8%, with an average harvested skin area of 70.08±8.94 cm². There was no significant relationship between the harvested skin area and the method of flap closure (direct closure vs. skin grafting) (p=0.48).

According to McConnell (1988), the tongue is a complex structure responsible for two main functions: swallowing and speaking. Swallowing consists of two phases: the first phase is the mixing of food, and the second phase is the propulsion of food down the throat and esophagus like a piston. For speech function, the tongue ensures pronunciation and helps maintain the airway along with the intrinsic tongue muscles and the geniohyoid and styloglossus muscles [21]. Brown (2006) [18] studied 566 patients with tongue and oral cavity cancer and found that the quality of life of patients who underwent tongue resection and reconstruction was worse than those who underwent palatal reconstruction in the first 12 months after surgery. We followed up with our patients for more than 24 months after surgery and found that 86.1% of patients had good speech recovery, meaning they spoke almost normally; 11.1% had fair speech, with some slurring but understandable; 2.8% had poor speech, with significant slurring, and none were unable to speak after surgery. Thankappan’s results showed that 51.4% of patients spoke normally and 48.6% had minimal slurring. This result differs somewhat from ours; however, we assessed speech function 24 months post-surgery, whereas Thankappan’s study followed up only 12 months after surgery. It is possible that the reconstructive tissue used for tongue reconstruction in their study was still stiff due to incomplete mucosalization, making pronunciation more difficult. Regarding swallowing function, we found very positive results: 90.61% of patients were able to eat normal food, and 9.8% could eat soft food. This result is similar to Thankappan’s findings, where 75.7% could eat normal food and 24.3% could only eat soft food.

Conclusion

The lateral arm flap is a suitable reconstructive material for tissue defects in the oral cavity following cancer resection. The flap meets the functional recovery requirements of both the tongue and the oral cavity after reconstruction, ensuring good speech recovery in 86.1% of patients and swallowing function in 90.61%. Immediate tongue reconstruction using a free flap after tumor resection is an effective treatment for oral cancer, yielding highly reliable results.