Discussion
This case series presents an alternative method for reconstruction of circumferential pharyngeal defects using a dual flap technique, with the rotated deltopectoral flap as the posterior wall of the neopharynx. The purpose of this technique is to reconstruct the neopharynx with minimal soft tissue bulk in the limited central compartment space, and to create a wider, conical conduit for food passage. A single tubed flap, with the exception of the jejunal free flap, incorporates all the flap bulk in the central compartment, limiting the calibre of the neopharynx. The deltopectoral flap positions naturally on the prevertebral fascia. The second flap being used as a patch flap as opposed to a tubed flap, allows the majority of the flap bulk to be located in the lateral neck.
To maintain continuity of the neopharynx, the flaps need to be sutured stepwise to the posterior pharyngeal wall postero-superiorly and to the tongue base supero-anteriorly. Similarly, the flaps are sutured inferiorly to the cervical oesophageal remnant forming a continuous food passage. This resulted in a conical shaped neopharynx (Figure 2), which resembles the natural pharynx more than a tubed flap reconstruction. The authors theorise that this wider, conical neopharynx would both enhance the swallow function, and allow improved air passage for speech. Our limited series seems to support this, with good functional outcomes reported.
The additional advantage to the DP flap, is that it can be rapidly raised and positioned on the posterior wall, requiring minimal de-epithelialisation. This also converts a complex circumferential defect into a ‘partial’ defect, and consequently, does not contribute significantly to the surgical time.
To the authors knowledge, the combination of a DP and a second flap has never been described before in the literature. Various techniques have been described for reconstructing circumferential defects, including tubed free flaps, tubed pedicled flaps, and suturing of flaps onto the prevertebral fascia. A recent multicentre study concluded that the type of flap used during reconstruction does not impact on the post-operative swallowing outcomes with just over half of patients being able to gain normal diet post-operatively (54% with any flaps; 63% RFFF. 53% PMMC, 58% FJF) with no significant difference between the different flaps being used. 5 Nevertheless, other series have demonstrated superior functional outcomes when free flaps were used (58% - 63% normal feeding; 21-25% stricture requiring dilatation) compared to tubed PMMC or PMMC with the prevertebral fascia forming the posterior pharyngeal wall (18-40% stenosis requiring dilatation; 53-91% adequate oral nutrition; 43% satisfactory vocal function).10-13
In our case series, all patients ultimately achieved oral diet intake, with 7 patients achieving sufficient intake to support their complete nutrition. Only one patient developed a stricture requiring repeated dilatation. All patients who were able to receive a tracheooesophageal puncture attained intelligible speech. The need for post-operative dilatation of the neopharynx is frequently reported in the literature when tubed free or single pedicle flaps are used for reconstruction of circumferential pharyngolaryngeal defects. Dilatation figures vary from 21% with the FFF to 40% with PMMC. 5
The main weakness of the dual flap technique lies in the likelihood of patients developing a small fistula. This occurs at the de-epithelialised region on the DP flap. While an important consideration in the perioperative period, this has not impacted on subsequent care or adjuvant treatment delivery in any of the patients involved. The fistula has always remained small and low volume, requiring minimal/no intervention, and the authors are of the opinion that the long-term functional outcome advantages outweigh the consequences of fistula development. In fact, it may be that the small fistula is advantageous, allowing a means of controlled drainage, as none of the patients have developed significant tissue breakdown. The factors that pre-dispose to fistulae have been investigated extensively in previous studies, including comparing between free and pedicled tissue flaps. 14-16 Despite a recent trend towards increasing free flap use, morbidity profiles appear to be similar between free and pedicled flaps 16. Although all patients in our case series developed a fistula, the short-lived nature, and the rapid healing indicate that dual flap use appears to be a robust reconstruction technique.