Type 1 Thyroplasty Procedure
Type 1 thyroplasty (medialization thyroplasty) is performed under local anesthesia with sedation to allow real-time voice monitoring, involving creation of a thyroid cartilage window at vocal cord level, medial displacement of the paralyzed vocal fold using an implant or cartilage wedge, and intraoperative voice assessment to achieve optimal medialization. 1, 2
Preoperative Preparation
Patient Selection and Assessment
- Primary indication: Unilateral vocal fold paralysis causing dysphonia with breathy voice, vocal fatigue, and inadequate glottic closure 1, 3
- Vocal fold atrophy is also an appropriate indication 1
- Perform preoperative laryngoscopy to document vocal fold position and mobility 3
- Obtain baseline voice measurements including fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, mean phonation time, and glottal gap quantification 3
Anesthetic Approach
- Use monitored local anesthesia with sedation to permit patient phonation during the procedure for real-time voice assessment 1, 2
- This allows precise adjustment of medialization based on immediate voice quality feedback 1
Surgical Technique
Incision and Exposure
- Make a horizontal skin incision over the thyroid cartilage at the level of the vocal cord 1
- Expose the thyroid cartilage lamina on the affected side 1
Cartilage Window Creation
- Create a rectangular window in the thyroid cartilage at the level of the vocal cord (typically 5-7mm above the inferior border of the thyroid cartilage) 1, 4
- For calcified cartilage, cut with minimal soft tissue intervention 4
- The window should be positioned to correspond with the membranous vocal fold 1
Medialization
- Depress the cartilage fragment inward to medialize the vocal fold 1
- Use a cartilage piece harvested from the contralateral thyroid ala as a wedge if needed to enhance lateral compression 1
- Alternatively, place a silicone implant inside the window to push the paralyzed cord medially 2
- Fix the window with a silicone plug to enhance and maintain medialization 4
Intraoperative Adjustment
- Achieve overmedialization of the vocal cord during surgery, as some reversion can occur postoperatively 4
- Have the patient phonate repeatedly during the procedure to assess voice quality and adjust the degree of medialization 1, 2
- Fine and reliable adjustment of depression is possible because surgical intervention inside the thyroid cartilage is minimal 1
Postoperative Management
Immediate Care
- Discharge patients within 24 hours for uncomplicated unilateral procedures 5
- Day-case surgery is feasible for carefully selected patients without anticoagulation, revision surgery, or atrophic/irradiated laryngeal tissue 5
- Monitor for airway compromise, though this complication is rare with proper technique 2, 5
Follow-up Assessment
- Perform postoperative voice analysis including acoustic measures (jitter, shimmer, noise-to-harmonic ratio) and aerodynamic measures (mean phonation time, mean flow rate, mean subglottic pressure) 3
- Quantify glottal gap reduction with videostroboscopy 3
- Expected outcomes include significantly reduced glottal gap, improved pitch and amplitude perturbation, increased phonation time, and improved subglottic pressure 3
Critical Pitfalls and Complications
High-Risk Patients
- Patients on anticoagulation (e.g., warfarin) have increased risk of postoperative hematoma 5
- Revision thyroplasty cases carry higher infection risk (occurred in 2 of 57 patients at 3 days postoperatively) 5
- Patients with prior radiotherapy may develop implant erosion through atrophic mucosa months later 5
Technical Considerations
- Voice reversion can occur postoperatively if medialization is inadequate 4
- Ensure adequate fixation of the implant or cartilage wedge to prevent displacement 4
- Avoid excessive medialization that could cause airway compromise, though this is rare 2