3d computed tomography analysis of arytenoid adduction in patients with unilateral vocal fold paralysis.

Laryngeal framework surgery is a commonly used technique to improve closure of
the focal cords in patients with closing deficits of the vocal cords. The basis
procedure consists of medialization of the vocal fold to which an arytenoid
adduction can be added. The main goal is to improve glottis closure, and
thereby improve voice quality. This additional arytenoid adduction is highly
advocated by some surgeons but deemed less necessary by others.

Laryngeal Framework Surgery including medialization and arytenoid adduction
technique is performed under local anesthesia. The muscle process of the
arytenoid is pulled by two 3-0 nylon sutures in simulation of the functions of
the lateral cricoarytenoid muscle and the lateral thyroarytenoid muscle.

Arytenoid adduction is indicated when dysphonia due to unilateral vocal cord
paralysis is particularly associated with a large, glottal chink and with a
level difference between the two cords during phonation.

Several factors contribute to the maximum voice result in LFS surgery. During
surgery after medialization an estimation is made if arytenoid adduction is
necessary to improve the voice more than just with medialization alone. The
surgeon concludes in agreement with the patient if this arytenoid adduction is
added.

Two-dimensional endoscopy and stroboscopy is a common approach for examining
the vocal folds pre- and postoperatively. However, this approach has some
limitations in visualizing the level of the vocal fold and estimating the
vertical movements of the arytenoid and vocal folds. Investigations with
high-resolution computed tomography (HRCT) offer a three-dimensional view. With
HRCT, the influence of the medialization implant on the arytenoid cartilage can
be evaluated and quantitatively measured.

Assessment of the change of position of the arytenoid cartilage after laryngeal
framework surgery including medialization thyreoplasty and arytenoid adduction.
The position of the arytenoid will be assessed at baseline pre-operative and 3
months post-operative.

Observational explorative study. Patients will undergo two CT-scans. The first
scan will be pre-operative. The second scan will be 3 months post-operative.

Burden: The burden associated with participation in this study is the time it
takes to do 2 CT-scans. No additional hospital visits are required as the first
CT-scan will be planned during hospital admission before surgery, or
simultaneously with pre-operative hospital visit, and the second CT-scan will
be combined with the standard follow-up visit at 3 months.

Risk: 2 CT-scans will be planned, without IV-contrast. There is a small risk of
radiation induced disease (1:100.000). The radiation dose is calculated at 0.33
mSv / scan.