Functional soft palate reconstruction

Abstract

Background: The excision of oropharyngeal carcinoma of more than 50% of the soft palate followed by static reconstruction may result in functional deficits, including velopharyngeal insufficiency, swallowing, and speech difficulties. We describe a functional soft palate reconstruction technique aimed at restoring aeromechanical and acoustic functions, enabling swallowing without nasal regurgitation and speech with low nasalance.

Material and methods: We developed a new operative technique, using muscle transfer and a free flap to create a dynamic reconstruction. To prove the distinct nerve innervation of the two digastric bellies and the feasibility of the technique, we first performed an anatomical study, and then implemented the technique in our clinic. The surgical technique included transfer of the anterior and posterior bellies of the digastric muscle in association with a folded radial forearm free flap. A retrospective analysis of patients who underwent this soft palate functional reconstruction after cancer resection between 2007 and 2017 was performed, and a subjective analysis of nasalance and swallowing was done to evaluate the functional outcomes.

Results: Eight patients (six males, two females) with a mean age of 56 years (range 43-69) who were affected by oropharynx carcinoma (stage T1-3) infiltrating the soft palate were included. Analysis of the reconstruction showed that seven of the eight patients had satisfactory swallowing function, and all patients were able to speak in an understandable manner with minimal nasalance.

Conclusions: Our surgical approach provided a functional reconstruction with outcomes close to normality, making it a suitable technique for patients with large soft palate defects.

Keywords: Digastric muscle; Functional reconstruction; Oropharyngeal carcinoma; Soft palate reconstruction.

Figure 1

Transposition of the digastric muscle with the overlying stylohyoid muscle.

Figure 2

Schematic pictures of the tumor location, defect size, and posterior inset of the radial forearm free flap.

Figure 3

Defect after cancer resection with nasogastric tube.

Figure 4

View of the digastric muscle with its two muscle bellies and the interjacent tendon in the context of the neck dissection.

Figure 5

Preoperative planning of the radial forearm free flap and closure of the donor side.

Figure 6

Schematic and intraoperative picture of fixed muscle showing the sandwich technique after inset of the posterior wall of the radial forearm free flap.

Figure 7

Schematic and intraoperative picture after inset of the anterior wall of the radial forearm free flap.

Figure 8

Intraoperative pictures showing the sandwich technique. a. Flap inset of the posterior wall of the radial forearm free flap (RFFF) inside out and the transposed digastric muscle. b and c. Digastric muscle lying between the posterior and anterior wall of the folded RFFF. d. Sutured anterior wall of the RFFF to the remnant borders of the defect zone to close the sandwich.

Figure 9

Anatomical study showing the independent innervation of the posterior belly of the digastric muscle from behind. Arrow indicates ramus digastricus coming from the facial nerve.

Figure 10

Separate innervation of anterior belly of digastric muscle, view from lateral on submental region. Arrow indicates mylohyoid nerve, star indicates anterior belly of digastric muscle, circle indicates submental, and rectangle is showing stylohyoid muscle surrounding intermediate tendon of digastric muscle.

Figure 11

Anatomical study with view of the posterior belly of the digastric muscle and its separate innervation (arrow).

Figure 12

View from lateral on the nerve and artery entering the posterior belly from behind.

Figure 13

Mobilized anterior muscle belly before transfer.

Figure 14

View from anterior into the oral cavity after muscle transfer (part of mandible removed for demonstration): White circle is showing defect of soft palate and arrow is showing anterior belly of digastric muscle.

Figure 15

View from anterior right oblique after muscle transfer (part of mandible removed for demonstration) showing anterior and posterior muscle bellies with the intermediate tendon.