Evaluation of postoperative function in patients undergoing reconstruction following resection of superior and lateral oropharyngeal cancer: long-term outcomes of reconstruction with the Gehanno method

Abstract

Resection of the superior or lateral wall of the cancer-affected oropharynx can often lead to disturbed nasal breathing, dysphagia, and dysarthria. The authors used the Gehanno method to reconstruct these surgical defects and achieved favourable functional recovery soon after surgery. The present study was undertaken to analyze the long-term outcome and usefulness of this method. Reconstruction was carried out using the Gehanno method in 36 patients during the 10-year period between 1997 and 2007. Both short-term and long-term evaluations of the postoperative function were performed in 12 of the 36 cases. The postoperative function was favourably maintained in all 12 cases, but gradual deterioration was noted in some cases in which the forearm flap had been used for reconstruction. Conventionally, the forearm flap is considered suitable for the reconstruction of complex structures such as the oropharynx because of its excellent flexibility. The results suggest that if the forearm flap is used for reconstruction using the Gehanno method, the surrounding tissue is likely to undergo change over time. The rectus abdominis myocutaneous flap should be considered as the first-choice flap for reconstruction using the Gehanno method.

The oropharynx and its surrounding structures such as the soft palate and tonsils play important roles in articulation and swallowing. Surgery in this region should be performed carefully to prevent loss of the physiological function of these structures.

For functional recovery after resection of superior and lateral oropharyngeal cancer, the authors applied a technique in which a narrow border is created between the superior pharynx and the oropharynx (whilst avoiding disturbance in nasal breathing), similar to the velopharyngoplasty reported by G ehanno et al. , and the technique reported by O mura et al. was used to reconstruct the lower part of the fauces such that it is narrow and high . The authors have reported that reconstruction with this technique (hereafter called Gehanno method) enables favourable functional recovery soon after surgery . To date, several cases have reported short-term (less than 1 year) evaluations of functional recovery after reconstruction performed using various techniques , but few studies have reported the long-term outcomes of these techniques . Only 1 study (published by the authors) has reported the long-term outcomes of reconstruction performed using the Gehanno method . In this study, the authors have evaluated functional recovery more than 2 years after reconstruction with the Gehanno method and compared the long-term results with the short-term results to analyze the long-term usefulness of this method.

Materials and methods

During the 10-year period between 1997 and 2007, 36 patients underwent oropharyngeal reconstruction using the Gehanno method. In 12 of these 36 patients, follow-up was continued for 2 years or longer after surgery. The postoperative function (described later) was evaluated for these patients, and this allowed comparison of the long-term and short-term outcomes. These 12 patients were analyzed in this study. The survival data for these 12 patients did not correlate with the survival data of all the patients who underwent the operation at the authors’ facilities. Of the 24 patients for whom postoperative function could not be evaluated, 5 died of an underlying disease, 3 died of other causes, 3 could not be followed up, and 13 could not be evaluated. The reasons for the 13 not being evaluated were: lack of cooperation in 4; accompanying disease in 2 (1 postoperative cerebral infarction and 1 depression); combined resection of some organs in 7 (3 subtotal glossectomy, 3 resection of the mandible and 1 total laryngectomy). Neither short-term nor long-term evaluation of function was possible for the 13 patients who could not be evaluated.

The ages of the 12 patients at the time of surgery ranged from 51 to 68 years (mean 60.3 years). The ages of the patients at the time of evaluation of the long-term results ranged from 54 to 71 years (mean 64.2 years). All 12 patients were men. The site of the primary cancer was the lateral wall in 10 cases and the superior wall in 2 cases. At the first examination, the tumour was rated according to the T classification system: T1 in 1 case; T2, 4 cases; T3, 1 case; and T4, 6 cases. The authors adopted the draught classification system proposed by M iura et al. to classify the extent of the defects ( Fig. 1 ) because the evaluation of postoperative function is closely dependent on the extent of the oropharyngeal defects.

Figure 1
Classification of the extent of defects in the oropharynx (draught).
Source : M iura et al. .

All 12 patients received preoperative radiation (about 40 Gy). In the cases in which excision in the parapharyngeal space was required, the operative field was developed using a mandibular swing approach , and reconstruction was performed using a rectus abdominis myocutaneous flap. In the cases in which excision in the parapharyngeal space was not required, reconstruction was performed using an intraoral technique with a forearm flap. The rectus abdominis myocutaneous flap was used for reconstruction in 7 cases, whereas the forearm flap was used in 5 cases ( Table 1 ).

Table 1
Patient data.
Patient Age Sex T classification Defect type Reconstruction
1 58 M T1 IIb FA
2 58 M T2 IIIa FA
3 63 M T4 IIIa RAMC
4 65 M T4 IIa FA
5 51 M T2 IIIa FA
6 64 M T2 IIIa RAMC
7 61 M T3 IIIb RAMC
8 53 M T4 IIIa FA
9 68 M T4 IIIa RAMC
10 60 M T2 IIIa RAMC
11 56 M T4 IIIa RAMC
12 67 M T4 IIIa RAMC

FA: forearm flap, RAMC: rectus abdominis myocutaneous flap.

Procedure for reconstruction

The procedure is shown in Fig. 2 . First, the pharyngeal mucosa was freed from the pharyngeal posterior wall stump over the prevertebral fascia, and the pharyngeal myomucosal flap, which was composed of mucosa and the superior pharyngeal constrictor, was raised. In this step, freeing of the mucosa was done to the minimum degree possible. Next, the pharyngeal myomucosal flap was everted in the superomedial direction and sequentially sutured to the residual soft palate stump.

Figure 2
Procedure for reconstruction. (1) Resection of the lateral wall and superior wall (including a part of the lingual root) of the oropharynx. (2) Freeing of the pharyngeal myomucosal flap from the oropharyngeal posterior wall stump (*), followed by superomedial eversion. (3) Suturing of the pharyngeal myomucosal flap to the soft palate and hard palate stump in sequences, followed by suturing of the lingual root to the pharyngeal posterior wall stump. (4) Covering of the exposed mucosal defect with the free flap.

Thus, a new velopharyngeal port surrounded by the mucosal plane was formed, the border between the superior pharynx and the oropharynx having been decreased to less than half of its original size. At the lower end of the pharyngeal lateral wall, the pharyngeal posterior wall stump was sutured to the lingual root stump as far as possible to ensure that the lower part of the fauces was narrow and high. In the last step, the flap was sutured to the defective areas of the exposed superior pharynx constrictor, pharyngeal posterior wall, pharyngeal lateral wall, and other areas of the oral cavity and oropharynx, and the wound was covered. Covering the wound marked the end of the reconstruction procedure.

Procedure for reconstruction

The procedure is shown in Fig. 2 . First, the pharyngeal mucosa was freed from the pharyngeal posterior wall stump over the prevertebral fascia, and the pharyngeal myomucosal flap, which was composed of mucosa and the superior pharyngeal constrictor, was raised. In this step, freeing of the mucosa was done to the minimum degree possible. Next, the pharyngeal myomucosal flap was everted in the superomedial direction and sequentially sutured to the residual soft palate stump.

Figure 2
Procedure for reconstruction. (1) Resection of the lateral wall and superior wall (including a part of the lingual root) of the oropharynx. (2) Freeing of the pharyngeal myomucosal flap from the oropharyngeal posterior wall stump (*), followed by superomedial eversion. (3) Suturing of the pharyngeal myomucosal flap to the soft palate and hard palate stump in sequences, followed by suturing of the lingual root to the pharyngeal posterior wall stump. (4) Covering of the exposed mucosal defect with the free flap.

Thus, a new velopharyngeal port surrounded by the mucosal plane was formed, the border between the superior pharynx and the oropharynx having been decreased to less than half of its original size. At the lower end of the pharyngeal lateral wall, the pharyngeal posterior wall stump was sutured to the lingual root stump as far as possible to ensure that the lower part of the fauces was narrow and high. In the last step, the flap was sutured to the defective areas of the exposed superior pharynx constrictor, pharyngeal posterior wall, pharyngeal lateral wall, and other areas of the oral cavity and oropharynx, and the wound was covered. Covering the wound marked the end of the reconstruction procedure.

Evaluation of postoperative function

The presence or absence of disturbances in four functions (nasal breathing, articulation, swallowing, and nasopharyngeal cavity closing function) was evaluated at about 6 months and 2 years after the operation, and the results obtained at the two time points were compared. The long-term results were recorded between 25 and 76 months after surgery (median 41 months).

The presence or absence of disturbed nasal breathing was evaluated by checking for subjective symptoms of nasal congestion and by analyzing the inspired and expired air and the time course of subjective symptoms from immediately after surgery to the time of the long-term outcome evaluation.

The articulation function was evaluated by analyzing speech clarity whilst the patient read a paragraph of a story aloud and by calculating the clarity of 100 monosyllabic Japanese words selected for the oropharyngeal function test . The clarity of velar consonants for 16 of these 100 words (velar consonant clarity) was also evaluated.

The swallowing function was evaluated using a questionnaire survey of the diet menu, time taken for eating, and inconvenience encountered whilst swallowing. The swallowing function was also evaluated objectively using video fluorography (VF).

The nasopharyngeal closing function was evaluated on the basis of the results of the blowing test , by calculating the ratio (%) of the duration of soft blowing during nasal opening to that during nasal closure per expiration (‘blowing ratio’).

Results

Nasal breathing

In the evaluation of subjective symptoms, none of the patients complained of disturbed nasal breathing during inspiration or expiration, and none of the patients experienced nasal congestion from the time immediately after surgery to the time of the long-term outcome evaluation. Intensification of snoring during sleep was observed in some patients but this finding was not considered a subjective symptom.

Articulation

On the basis of the criteria for the evaluation of speech function proposed by Hirose (a member of the Ministry of Health and Welfare cancer study group ‘59-8: Establishment of treatment methods for oral and oropharyngeal cancer and evaluation of post-treatment function’) , speech clarity was rated as excellent (score 8–10) in all 12 patients. When the changes in speech clarity were analyzed in the same patients, the score tended to worsen slightly in patients who had undergone reconstruction with the forearm flap (cases 1, 2 and 8; Fig. 3 ).

Jan 26, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Evaluation of postoperative function in patients undergoing reconstruction following resection of superior and lateral oropharyngeal cancer: long-term outcomes of reconstruction with the Gehanno method
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