Stephanie Benoit April 11, 2016

Dr. Claudio Storck is an otolaryngology specialist at the University Hospital of Basel, Switzerland. He primarily focuses on studying the factors of success involved in cricoid-thyroid approximation (CTA) in trans-women, which is an operation that can sometimes help to elevate the vocal pitch of the patient.

An unsatisfactory outcome

CTA is the most commonly used tactic, and it involves approximating the cricoid cartilage to the thyroid cartilage, thereby tilting back the cricoid plate as well as the arytenoid cartilage. This has the effect of elongating the vocal fold, and increasing the vocal pitch of the patient. However, this procedure fails to achieve its desired outcome in about one third of patients. Therefore, Dr. Storck sought to predict the outcome of these operations. In this way, the patient could avoid going through an entire operation if their anatomy was not optimal for the procedure. Dr. Storck achieved the first prize in the Europe and Africa category of the Mimics Innovation Awards in 2015 for this research.

Larynx: antero-lateral-view
Antero-lateral view of the larynx © Olek Remesz

 

 

Visualizing three distinct CTJ types

Previous studies have defined three types of crico-thyroid joints (CTJ), called A, B and C. Type A has a well-defined joint, with a clear cartilaginous protrusion, and is the type that presents the most chance of a successful CTA outcome. Types B and C have poorly defined (or even flat) joints with no clear protuberance, and are most likely to result in an unsuccessful CTA.

Using Materialise Mimics software, Dr. Storck and his team were able to create 3D images of the larynx from high-resolution CT scans of the patients’ pre-operative crico-thyroid joints. The different types of CTJs were clearly visible on the 3D images, and Dr. Storck examined whether these different CTJ types correlated with the results of the surgery.

Thyroplasty research: 3D-image of a larynx cut at the level of the crico-thyroid jointRight oblique frontal view on the 3D-image of a larynx cut at the level of the crico-thyroid joint. Type A shows the typical protuberance (arrow); Type B/C shows a flat surface of the cricoid part (arrow). right-hemi-larynx-cricoid-plate_ View from the left on a right hemi-larynx with the preoperative and postoperative positions of the cricoid plate superimposed.

 

Predicting thyroplasty results

He found that there was a significant difference: ten out of the eleven trans-women with type A came out of the surgery with a satisfactory outcome, and none of the surgeries performed on the trans-women with type B or C produced a satisfactory result. Based on these results, Dr. Storck concludes his research by saying that the 3D images of the patients were vital in aiding them to distinguish the type of CTJ in the patient, and that this type should be the deciding factor when assigning CTA to the patient – only patients with a type A CTJ should be considered. Convinced by the benefits of 3D images, Dr. Storck is now always using the technology when performing a CTA operation. 3D-reconstructed-postoperative-larynx_

Left oblique frontal view on a 3D reconstructed postoperative larynx. The thyroid and cricoid cartilages are approximated with two monofile thread loops running through the holes of the two manually adjusted titanium miniplates to prevent shearing of the threads through the cartilages.

About the author Dr. Claudio StorckDr. Claudio Storck is an assistant professor and surgeon at the University Hospital of Basel, Switzerland. He is specialized in otolaryngology and is currently the head of laryngology and phoniatrics at the ENT-department. In 2015, he won a Mimics Innovation Award for his research on the Cricothyroid joint anatomy as a predicting factor for the success of cricoid-thyroid approximation in trans-women. Read more publications from Dr. Claudio Storck on ResearchGate

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