Treatment for Adductor Spasmodic Dysphonia by Type 2 Thyroplasty Using Titanium Bridges
Condition: Adductor Spasmodic Dysphonia
MeSH terms: Dysphonia; Hoarseness
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      For adductor spasmodic dysphonia, there is a need for establishing a new therapy under the
      present circumstance where no standard therapy has been established yet and existing
      therapies fail to provide permanent effect. Evaluation of the efficacy of type 2 thyroplasty
      using titanium bridges will expand the therapeutic options available for adductor spasmodic
      dysphonia and establishment of a standard therapy.
    

Detailed description: 
      Spasmodic dysphonia is a type of functional dysphonia not associated with any organic
      abnormality or palsy of the larynx. The speech disorder in this disease is caused by
      involuntary and intermittent spasms of the intralaryngeal muscles (Castelon, 2002).

      There is no curative treatment for this disease. Conservative therapies include voice
      training (voice therapy) and muscle relaxant medication to ease the tension in the larynx
      during speech, although there is not much evidence to support the effectiveness of either. An
      internationally employed therapy is local injection of botulinum toxin A into the
      intralaryngeal muscles to suppress involuntary movements of the vocal cords. The injection
      can be administered percutaneously from the anterior neck within a short time, and a number
      of reports have indicated a greater than 90% efficacy of this treatment (Tisch 2003, Blitzer
      2010). However, this local injection therapy is effective only for a limited period of 3 to 4
      months, and periodic injections have to be continued throughout life for maintaining relief
      from the symptoms under the present circumstances.

      Type 2 thyroplasty is an operative procedure in which the thyroid cartilage is incised at the
      midline, and the incised gap is opened and fixed with the thyroarytenoid muscles attached on
      both sides, so that the vocal cords do not shut too tightly during speech even with strong
      adduction of the glottis, as the symptoms of adductor spasmodic dysphonia are caused by
      excessive closure of the glottis due to strong involuntary and intermittent adduction of the
      intralaryngeal muscles (Isshiki 2001).

      In 2002, the titanium bridge made of biocompatible pure titanium was developed in Japan for
      exclusive use in type 2 thyroplasty (Isshiki 2004). When the titanium bridge was used in
      actual cases, the symptoms disappeared without recurrence after the operation (Sanuki 2007,
      Sanuki 2009, Isshiki & Sanuki 2009, Sanuki 2010).

      There is a need for establishing a new therapy under the present circumstance where no
      standard therapy has been established yet and existing therapies fail to provide permanent
      effect. Evaluation of the efficacy of type 2 thyroplasty using titanium bridges will expand
      the therapeutic options available for adductor spasmodic dysphonia and establishment of a
      standard therapy.
    

Intervention name(s): Type 2 Thyroplasty using Titanium Bridges
Intervention type(s): Device
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Screening
Keywords: Spasmodic Dysphonia; Type 2 Thyroplasty; Titanium Bridges; Operation