INTRODUCTION

The treatment of laryngeal cancer has been through a number of important changes in the past twenty years owing to improvement in surgical techniques and also because of better understanding of tumor dissemination. Total laryngectomy, which leads to complete irreversible loss of vocal function, can be replaced in some cases by more conservative techniques that preserve phonation. Despite this advantage, dysphagia and aspiration are frequent postoperative complications of partial laryngectomy. Among the conservative techniques used, we can refer to anterior frontal laryngectomy by Tucker's technique as a therapeutic option for glottic tumors that affect the membranous portion of the vocal folds and the anterior commissure. This surgery can hinder laryngeal sphincter function, especially right after surgery, being that swallowing is normally restored on the 3rd to 4th postoperative weeks.

Anterior frontal laryngectomy was first described by Sedlacek-Kambic-Tucker (1) and studied again by Pech in France. The technique allows removal of the membranous glottic plan since arytenoid cartilages are preserved. The reconstruction is inspired in the studies by Freche (1964) and Bouche (1966) (2), which causes lowering of epiglottis on the frontal plan. The typical indication for this approach are tumor lesions that go around the anterior commissure and reach the vocal folds bilaterally (horseshoe lesion), without mobility impairment.

In recent years, high-frequency radiation has gained a highlighted position owing to safety and functional and oncological results (3, 4). Together with improvement of techniques and stricter criteria for indication, it has provided to laryngeal functional surgery a competitive situation for the therapeutic arsenal of head and neck surgeons and otorhinolaryngologists. Thus, open surgery and external radiotherapy are essential strategies in the treatment of laryngeal squamous cell carcinoma (5). Moreover, indications are still not a consensus in the literature owing to lack of randomized studies to compare effectiveness of both treatment options (6). In general, indications for radiotherapy or surgery are similar for tumors classified as T1 and T2, however, most T3 and T4 tumors require multimodal therapy, normally surgery plus adjuvant radiotherapy (7). Conversely, some factors can have relative influence in the therapeutic choice, such as patients' age, professional voice use, smoking and alcohol abuse, and some social-economic factors that may require short-duration solutions. Obviously, the purpose is always to cure cancer causing as minimum dysfunction as possible, with maximum quality of life after treatment and maximum possibility of cure (5). As to initial stage of tumors (T1 and T2), there is a common sense that partial removal of some specific laryngeal compartments is compatible with cure and produce appropriate functional results (8).

Since 1991, our Service of Bronchoesophagology and Head and Neck Surgery, HGB - RJ, has traditionally used radiotherapy and/or surgery to treat glottic cancer, with predominance of surgical indications. Based on this experience, we decided to analyze our results concerning oncological control of 24 patients with glottic cancer treated with anterior frontal laryngectomy by Tucker's technique, comparing them to the international literature.

MATERIAL AND METHOD

In the period between 1991 and 2003, 24 patients with glottic tumors in initial stages of the disease were submitted to anterior frontal laryngectomy and their medical charts were retrospectively analyzed (Graph 1). We analyzed epidemiological characteristics such as gender, age, smoking, alcohol abuse, histological type, location of tumor, impairment of margins by freezing, recurrence, time from tracheostomy, postoperative complications, adjuvant treatment with chemotherapy (Qt) or radiotherapy (Rx), and follow-up of patients.

In all analyzed cases, the main complaint had been progressive dysphonia. Patients were initially examined with indirect laryngoscopy and later biopsy was indicated. It was performed under topical anesthesia and sedation and we conducted subsequent analysis of tumor extension to supra and infraglottic regions. Once confirmed the diagnostic suspicion, anterior frontal laryngectomy was indicated to all patients.

Chest x-ray and analysis of associated comorbidities were conducted in all patients before the final decision for surgery.

Description of the Surgical Technique

Initially, we conducted direct laryngoscopy to confirm the exact location of the lesion, then orotracheal intubation under general anesthesia, and then tracheotomy at the 2nd and 3rd tracheal ring level. Next, we made neck transverse incisions at the level of the cricothyroid membrane with displacement of myocutaneous flap, which could vary depending on type of incision. Pre-laryngeal muscles were detached and laryngeal framework was identified. Next, we dissected the external perichondrium of both sides of the thyroid cartilage with exposure of major cornus. Thyroid cartilage was vertically sectioned (thyrotomy) at the junction of the external third and the two internal thirds on both sides. We opened the larynx through a horizontal incision at the level of the cricothyroid membrane and made a perpendicular incision to it up to the base of the thyroid membrane, going though the thyrotomy on the less affected side. Next, the base of the thyrohyoid membrane was opened horizontally with complete exposure of the lesion, which was totally removed (vocal folds, false vocal folds and anterior commissure) (Figure 3) with macroscopic safety margins. Next we released the lingual aspect of the epiglottis by dissecting medial and lateral glossoepiglottic ligaments, leading to lowering of the epiglottis at the frontal plan, which was sutured to the margins of the surgical site with vicryl 3.0 inferiorly to the cricohyoid membrane, and laterally to the external third of the remaining sides of the thyroid cartilage (Figure 4). A reinforced suture was made using the external perichondrium of the thyroid cartilage. We also placed a Pen-rose drain 1, closed it by plan, placed a metallic cannula and external dressings (Figures 5: surgery 1 to 12 and surgical pieces 1 to 2).

RESULTS

As to epidemiological characteristics, 21 patients were male (87.5%) and 3 were female (12.5%) (Graph 2). The age range was 31 to 65 years, mean age of 55.8 years and 23 patients were aged over 45 years. Out of 24 studied patients, 21 were smokers, 2 were non-smokers, 15 were alcohol abusers, 6 were not alcohol abusers, and 1 patient did not report smoking and 2 did not report alcohol abuse (Table 1).

None of the patients died postoperatively. Nine of our patients presented aspiration especially of liquids. Other postoperative complications were bleeding through the tracheostoma (2 patients), subcutaneous emphysema (1 patient), tracheostoma infection (2 patients), but most of them did not present any complication.

Only 3 patients were decannulized late at about 2months postoperatively, but most of them were decannulized on the 3rd or 4th postoperative week. In general, it was conducted after inclusion of proper oral feeding (Table 2).

Only one of our patients presented a 2nd primary tumor 10 years after the procedure, submitted then to total laryngectomy and radiotherapy; the patient is currently alive and free from the disease. Two patients did not maintain outpatient follow-up. One patient was maintained free from the disease for 5 years after the surgery and then did not come back. The other 20 patients are alive and free from the disease, with confirmed 10-year survival.

Most of them presented squamous cell carcinoma and 22 patients were in stage T1b and T2 (95.2%) and there were only 2 carcinoma in situ (4.8%).
All surgical pieces were submitted to intraoperative freezing process. Only 1 patient presented impaired resection margins and was referred to adjuvant radiotherapy.

DISCUSSION

The basic problem of tumors that affect the anterior commissure is the difficulty to separate intralaryngeal vestibular bands and vocal folds from the cartilaginous framework, considering that at this level the internal perichondrium is replaced by the insertion of Broyles' tendons; thus, we face greater risk of cartilaginous tumor invasion (9).

The anterior fontal laryngectomy described by Tucker is a surgical technique suitable for tumors limited to the glottic region that affect the membranous portion of the vocal folds and the anterior commissure. Its performance is justified by satisfactory functional results.

Two of our patients had carcinoma in situ, but upon carefully analyzing their medical chart, we observed that both had lesions that involved the anterior thirds of both vocal folds and anterior commissure. Moreover, one of the patients had intraepithelial neoplasm with atypia and the other had lesions that extended about 3mm to the subglottis. Therefore, endoscopic resection was contraindicated based on the principle of the involvement of the anterior commissure and extension to the subglottis, which are relative contraindications for the procedure.

Vocal assessment of the patients submitted to this type of tumor resection results in poor vocal quality, as described in the literature (10).
According to Y. Mallet (2001) (2), indications for epiglottoplasty are:

 true vocal fold carcinoma without deep invasion and preserved mobility;

 true vocal fold carcinoma with significant dysplasia of contralateral vocal fold;

 bilateral glottic carcinoma with or without superficial extension to anterior commissure.

The contraindications are:

 Vocal fold immobility. Some authors accept performance provided there is no arytenoid invasion (11, 12);

 Subglottic tumor extension greater than 5mm;

 Extensions to the supra-glottis;

 Severe chronic pulmonary disease;

 Severe cardiopathy that contraindicates general anesthesia.

According to the classical description by Tucker (11) and other surgeons (13), we may accept small invasions of epiglottis petiole, provided that they can be removed during the surgery and do not affect epiglottoplasty.

Local control of glottic tumors in initial stages is clearly the most important prognostic factor, since regional and distant metastases are rarely observed in these patients in the absence of local recurrence (5).

Tucker defended low neck incision (14) so that it could be prolonged to a possible neck dissection.

Anterior frontal laryngectomy allows removal of glottic lesions (T1b and T2) and reconstruction of surgical defect by epiglottoplasty. Functional and oncological results are satisfactory and justified.

Functional justifications are based on the fact that it is a surgery without effects on the respiratory route, with quick decannulation. During phonation, arytenoid preserves its bascule mechanism. During breathing, glottic space increases transversally. There is also preservation of sphincter movement. The preservation of the posterior third of the thyroid cartilage maintains the integrity of constrictor muscles, which facilitates the elevation of the larynx and its movements during swallowing. Thus, preservation of cricoid rings prevents stenosis.

The current anatomical rationale is based on dissemination of glottic tumors, which occurs anteriorly via anterior commissure and can extend to the contralateral fold. Laterally, the dissemination may occur via thyroid cartilage, in contact with the vocal muscle, and via cricothyroid membrane, whereas inferiorly it takes the elastic cone via.

The safety of the surgical procedure compensates the need to use a cannula for 3 to 4 weeks on average.

However, careful preoperative assessment should be made for precise surgical indication, comprising patients' social profile, since all these factors influence disease control rates in the long run.

CLOSING REMARKS

Anterior frontal laryngectomy is a functionally feasible surgery, but indications are precise and limited, directed ideally to glottic tumors that involve anterior commissure and membranous portions of the vocal folds, and lesions that do not affect mobility of the vocal folds.

The satisfactory functional and oncological results are motivating factors for further application of this surgical technique.





REFERENCES

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¹ Resident Physician, Service of Bronchoesophagology and Head and Neck Surgery, Hospital Geral de Bonsucesso (HGB) - Rio de Janeiro - RJ.
² Physicians, Service of Bronchoesophagology and Head and Neck Surgery, HGB.
³ Head of the Service of Bronchoesophagology and Head and Neck Surgery, HGB.

Study conducted at the Service of Bronchoesophagology and Head and Neck Surgery, Hospital Geral de Bonsucesso - Rio de Janeiro - RJ.

Address correspondence to: Drª Giordania Gomes Campos - Rua José Higino, nº 30 - Tijuca - Rio de Janeiro - RJ - Cep: 20520-200
Tel: (55 21) 9241-2246 - E-mail: giordaniagc@ig.com.br