Aerodynamic Characteristics Of The Groningen Low-resistance Voice Prosthesis

Objectives: Total laryngectomy, as surgical treatment for laryngx andlaryngopharynx carcinoma has a profound impact on the life of the patient. Loss of thelarynx creates a major communication problem. The inability to speak disrupts routineinteraction with others and results in considerable economic, social and psychologicalchanges for the patients. Failure to adjust often leads to permanent disability, socialwithdrawal, and even more serious consequences.It is for this reason that there havebeen several efforts for voice rehabilitation over the last 100 years. Surgical voicerestoration with trache-oesophageal(TE)shunt methods results in a good voice qualitywhen compared with other methods of substitute voice production, such as esophagealspeech, artificial larynx. Then the development of silicone one-way valve prostheses,introduced into the TE shunt, effectively prevents stenosis of the shunt as well asaspiration due to leakage of esophageal contents through the shunt. Prosthesic voicerehabilitation is now widely used in clinical practise and can be considered the mostsuccessful form of voice restoration currently available. So the need for a greaterunderstanding of the pressure, and flow dynamics in a post-laryngectomy patientspeaking with the aid of a tracheo-esophageal valve has been greater. In our experience,we present a validated method of determining in vivo pressure, flow and voiceparameters from patients using tracheo-esophageal voice prostheses post laryngectomy.Then the aerodynamic aspects of the Groningen low-resistance voice prosthesis inlaryngectomees have been studied and explained the clinical meaning.Methods: Total laryngectomy and primary voice restoration were performed in 24patients between June, 2004 and July, 2006. 20 patients originially hadtracheoesophageal puncture and inserted a low- resistance Groningen voiceprosthesis(VP) as a primary procedure. 4 patients had a secondary procedure. Wechoose the patients when they has used the VP for 15 days～1months. They can use theVP fluently and sustain phonation without interruption for 10 seconds and to counteasily from 1 to 15. The experimental set-up was designed to measure threeaerodynamic parameters (a) the sound pressure level(spl). (b) intratracheal pressure(pressure), this corresponds to the pressure acting on the tracheal surface ofthe valve. (c) airflow rate through the oesophageal source airway duringspeech(Flowrate). These parameters were measured simultaneously inlaryngectomiced patients when they speak with the VP. The relationships between thevariables were computed by means of Pearson's product-moment correlations.Results: (1) The correlation between SPL and Pressure was little significant(r=-0.081, p＞0.05). (2) The relationship between flowrate and SPL was littlesignificant(r=-0.037, p＞0.05). (3) The correlation between Pressure and flowrate waspositive (r=0.219, p＜0.05).Conclusion: (1) The aerodynamic model of Groningen low-resistance voiceprosthesis have provides a basis for future studies in this field. (2) This aerodynamicmeasurement is a invasive, acceptable to the patient, repeatable and quick to perform.It may be useful in mointoring patient progress and also in elucidating the mechanicsof prosthesis failure. (3) Myotomy is the most important feature determining patientsatisfaction with the speech after prosthetic voice restoration. In the future research, afurther significant decrease in airflow resistance can be expected to result frominnovations on functional pharyngoesophageal segment surgery rather than fromfurther minor reductions of airflow resistance of shunt valve prostheses.