The LaryngoscopeVC 2014 The American Laryngological,Rhinological and Otological Society, Inc.

Thyroid Ala Perichondrial Flaps for Subglottic Reconstruction

J. Drew Prosser, MD; Carrie M. Bush, MD; Gregory N. Postma, MD; Paul M. Weinberger, MD

Objectives/Hypothesis: Techniques available for reconstruction of the cricotracheal region in adults are currently sub-optimal. We sought to 1) understand the anatomic basis for the thyroid ala perichondrial flap, 2) describe the technique ofharvesting and intraluminal placement, and 3) learn the limitations of defects for which it can be used.

Study Design: Cadaveric anatomical study.Methods: In fresh cadaveric specimens, the perichondrium of the outer layer of the thyroid cartilage was elevated by

tracing the superior, medial, and lateral borders of each thyroid cartilage ala. The inferiorly based flap was then placed intothe airway through the cricothyroid membrane. The extent of coverage was measured.

Results: A total of 10 flaps were performed (6 male and 4 female). The average length of thyroid perichondrial flapsobtained was 1.67 cm. All flaps were able to completely cover the cricoid cartilage and extended to but did not cover the firsttracheal ring. Once placed intraluminally, the flaps extended 2.4 cm below the vocal cords. Using both flaps enabled coverageof the entire anterior 180 degrees of the airway lumen in all specimens. There were no significant differences in male/femaleor right-sided/left-sided flaps.

Conclusions: The thyroid ala perichondrial flap is technically feasible and can provide coverage of anterior airwaydefects up to approximately 2.4 cm below the true vocal cords. This flap could enable transfer of vascularized tissue to aid incricotracheal reconstruction.

Key Words: Airway reconstruction, subglottic stenosis, thyroid perichondrial flap.Level of Evidence: N/A

Laryngoscope, 00:000–000, 2014

INTRODUCTIONCurrent operative management of subglottic steno-

sis is based on the size, degree, and length of the ste-notic segment. Whereas several endoscopic operativeinterventions have been utilized, open techniques aregenerally required in patients with severe stenosis.1 Inopen reconstruction, the primary goal is to increaseluminal size either by resection of the stenotic segmentwith reanastamosis or by augmentation with animplanted material. The most widely utilized material isautogenous cartilage grafts, which are most often placedanteriorly as free grafts to augment the intraluminaldiameter.

Several different donor sites have been utilizedwith multiple modifications to provide vascularized tis-sue to a free cartilage graft. Providing a vascularizedimplant provides the theoretic benefits of improvedgraft survival with decreased cartilage remodeling.Additionally, the use of local pedicled flaps has theadvantage of utilizing the same operative site and the

ability to be performed in the same operative setting.Thyroid perichondrial flaps have been utilized for avariety of procedures, including reconstruction of par-tial laryngectomy defects2 and as a vascular supply ofthe pedicled thyroid cartilage flap.3 Previous work hasdemonstrated the utility of using perichondrium as afree tissue graft to line the internal tracheal lumen toimprove re-epithelization and decrease granulation tis-sue formation.4 Having used this flap to repair defectsin the anterior cricoid cartilage and the cricothyroidmembrane following emergent cricothyroidotomy, theauthors looked to investigate the feasibility and ana-tomic limitations of performing pedicled thyroid peri-chondrial flaps in a cadaver model to evaluate theextent to which they could be utilized for subglottic air-way reconstruction.

MATERIALS AND METHODSAfter institutional review board exemption was obtained,

fresh nonembalmed cadavers donated for anatomical researchand study were obtained. An apron incision was utilized andsubplatysmal flaps were elevated to expose the strap muscles,which were divided in the midline and removed from theirattachments to fully expose the airway from the thyroid carti-lage to the sternal notch.

A 15 blade was used to incise the thyroid ala perichon-drium in the midline and then traced around the lateral andsuperior margins on each side. Next, a freer elevator was usedto elevate an inferiorly based perichondrial flap (Figs. 1–4).This was then repeated on the contralateral side (Fig. 5). Theairway was divided in the midline through the cricoid down tothe third tracheal ring (similar to the incision made to place acostal cartilage graft).

From the Cincinnati Children’s Hospital Medical Center (J.D.P.),Cincinnati Ohio; James A. Haley Veterans’ Hospital (C.M.B.), Tampa,Florida; and the Georgia Regents University (G.N.P., P.M.W.), Augusta,Georgia, U.S.A.

Editor’s Note: This Manuscript was accepted for publication April30, 2014.

The authors have no funding, financial relationships, or conflictsof interest to disclose.

Send correspondence to Paul M. Weinberger, MD, 1120 15thStreet, BP4109, Department of Otolaryngology, Georgia Regents Univer-sity, Augusta, GA 30912. E-mail: pweinberger@gru.edu

DOI: 10.1002/lary.24757

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Fig. 1. Lateral view of the thyroid cartilage and trachea after expo-sure obtained. [Color figure can be viewed in the online issue,which is available at wileyonlinelibrary.com.]

Fig. 2. Inferiorly based perichondrial flap partially elevated. [Colorfigure can be viewed in the online issue, which is available atwileyonlinelibrary.com.]

Fig. 3. Superiorly based view showing elevation of the perichon-drial flap with a freer. [Color figure can be viewed in the onlineissue, which is available at wileyonlinelibrary.com.]

Fig. 4. Inferiorly based flap completely elevated. [Color figure canbe viewed in the online issue, which is available at wileyonlineli-brary.com.]

Fig. 5. Anterior view of bilateral flaps elevated. [Color figure canbe viewed in the online issue, which is available at wileyonlineli-brary.com.]

Fig. 6. Inferior view of flaps elevated and tunneled into the airway.[Color figure can be viewed in the online issue, which is availableat wileyonlinelibrary.com.]

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Next, both flaps were tunneled through the cricothyroidmembrane, placed into the airway lumen, and connected in themidline (Fig. 6). This maneuver can be accomplished withoutextensive removal of the cricothyroid muscle insertion. The infe-rior extent of the flap was then measured using calipers, aswell as the extent to which it covered the intraluminal surfacerecorded.

RESULTSA total of 10 flaps were performed (6 male and 4

female). The average length of thyroid ala perichondrialflaps obtained was 1.67 cm (range 1.3–2 cm). All flapswere able to completely cover the cricoid cartilage, andin 60% of specimens they extended to but did not coverthe first tracheal ring. The flaps were able to completelycover the first tracheal ring in 40% of specimen. Onceplaced intraluminally, the flaps extended 2.4 cm (range2.1 cm–2.6 cm) below the vocal cords. Using both flapsenabled coverage of the entire anterior 180 degrees ofthe airway lumen in all specimens. There were no signif-icant differences in the male and female cartilages or inthe right-sided and left-sided flaps; however, all femaleflaps were able to completely cover the first trachealring, whereas in the male specimens the flaps extendedto but did not cover the first tracheal ring.

DISCUSSIONThe thyroid ala perichondrial flap is technically fea-

sible and can provide coverage of anterior airway defectsup to approximately 2.4 cm below the true vocal cords.As the perichondrium provides random patterned bloodsupply to the underlying cartilage; this flap enablestransfer of vascularized tissue to aid in cricotrachealreconstruction and repair of defects after cricoidthyroi-dotomy. In addition, this flap has the advantage of beingin the operative field and not requiring a separate inci-sion. It can be coupled with a chondral graft of choiceand lines the internal airway for improved epitheliza-tion. Additional vascular tissue could be rotated to coverthe external tracheal lumen to further improve vascular-ity via a pedicled muscular flap or even a free flap.

The drawbacks of this flap include its relative deli-cate nature and the limitation of reconstructing onlysubglottic defects because it was not able to extendbelow the first tracheal ring. It is yet to be determined ifthis will have effects on donor cartilage; however, this isunlikely due to the fact that the internal perichondriallining of the thyroid cartilage is left undisturbed. Addi-tionally, the external thyroid cartilage perichondrium isoften disrupted during laryngeal framework surgery,

with little to no effect noted on the underlying cartilageitself. Also yet to be elucidated is the degree to whichthe intraluminal flap will improve cartilage survival,decrease graft remodeling, and improve intraluminal re-epithelization. Further work in animal models is in pro-gress to examine these factors. Previous work has beendone utilizing a prefabricated sternohyoid myocartilage-nous flap that is rotated into the airway in an attemptto improve graft survival and mucosal re-epithelizationin patients with long segment stenosis.5 This studyoffers another option for providing local vascularized tis-sue to aid in cricotracheal reconstruction.

Although this cadaver study describes the harvest-ing, placement, and anatomic characteristics of the flap,there are several limitations to this study. This flap hasnot been previously described for airway reconstruction;therefore, the exact indications and applicability haveyet to be defined. In addition, because primary airwayreconstruction has a high success rate with low rates ofgraft loss, it is unlikely that this flap will be required forprimary airway reconstruction. The one notable excep-tion would be for primary reconstruction of small defectsleft by emergent cricothyroidotomy, for which our grouphas successfully used this flap over the past severalyears. Finally, this cadaveric study does not assess thedurability of the vascular supply that the flap provides,or whether clinically the flap will improve graft mucosal-ization and survival. Additional animal studies can beused to answer these questions.

CONCLUSIONThis flap has shown to be technically feasible in

human cadavers and can provide vascularized tissue andinternal tracheal lining of defects up to 180 degrees of theanterior subglottis, extending 2.4 cm below the vocal cords.

BIBLIOGRAPHY

1. Santos D, Mitchell R. The history of pediatric airway reconstruction.Laryngoscope 2010;120:815–820.

2. Lim YC, Son EJ, Kim K, Kim KM, Choi EC. Perichondrial flap to preventchondritis and cartilage necrosis in salvage vertical partial laryngec-tomy for recurrent glottic carcinoma after irradiation: a new procedure.Acta Otolaryngol 2005;125:659–663.

3. Fry TL, Fischer ND, Pillsbury HC. Tracheal reconstruction with pedicledthyroid cartilage. Laryngoscope 1985;95:60–62.

4. Cui P, Gao P, Luo J, Ruan Y. Thyroid alar cartilage graft laryngotrachealreconstruction in adults. Otolaryngol Head Neck Surg 2011;144:747–750.

5. Nouraei SAR, Nauraei SM, Sandison A, Howard DJ, Sandhu GS. The pre-fabricated sternohyoid myocartilagenous flap: A reconstructive optionfor treating recalcitrant adult laryngotracheal stenosis. Laryngoscope2008;118: 687–691.

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