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The gold standard for voice restoration after total laryngectomy is tracheoesophageal puncture (TEP). The TEP is a small surgically created fistula in the tracheoeosphageal (TE) wall that may be created at the time of the total laryngectomy (primary TEP) or later after the patient has healed from surgery (secondary TEP). A one-way valved silicone voice prosthesis (VP) is placed into the TEP. The prosthetic valve opens to allow pulmonary air into the vocal tract for vibratory sound production when the tracheostoma is occluded, but remains closed to prevent aspiration of foods/liquids during swallowing.1,2 One of the most difficult complications to manage after TEP is enlargement of the TE fistula that results in aspiration of saliva, liquid, and/or food around the VP into the trachea. Tissue changes associated with radiation, malnourishment, diabetes, smoking, and hypothyroidism may reduce elasticity and integrity of the TEP and have been implicated as potential risk factors for enlarged puncture.3–6 Development of an enlarged TEP has also been associated with acute infection or tumor recurrence.3,7 However, the actual contribution of these potential risk factors is unclear. An enlarged TEP intuitively increases the risk of pneumonia and respiratory complications due to frequent aspiration around the VP. Reduced tissue elasticity also increases the likelihood of spontaneous dislodgement of the VP and consequently the potential for aspiration of the prosthesis. Various treatments, including surgical closure of the TEP, have been proposed to mitigate the ill-effects of an enlarged TEP. Although surgical closure eliminates problems associated with leakage around the prosthesis, closure of the TEP prevents TE voice production, thus negatively impacting quality of life. Because of this, conservative methods, either surgical or nonsurgical, that aim to eliminate leakage around the VP while preserving functional TE voice, either surgical or nonsurgical but excluding complete TEP closure, are of particular interest. Although a variety of conservative treatments have been proposed, there are no clear guidelines for the conservative management of this complication. A better understanding of factors associated with enlarged TEP will lead to more uniform assessment and management of this complication, and may guide preventive efforts. For this purpose, a systematic review was conducted with the following objectives: (1) to estimate the rate of enlarged TEP causing leakage around the VP after total laryngectomy with TEP, (2) to estimate the risk of pneumonia in patients with enlarged TEP, (3) to summarize the effect of potential risk factors for enlarged TEP, and (4) to summarize the type and effectiveness of conservative treatments used to prevent leakage around the prosthesis due to enlarged TEP.

A stochastic model describing the movements, resulting from a smoking cessation program, of a cohort of individuals from the smoking to the non-smoking compartment is proposed. The distribution and first two moments of the number of smokers are derived.

This paper analyzes the waiting-time distribution of a specific job as it moves through a job-shop with multiple centers and exponential service times. The movement of the job through the shop is governed by a Markovian transition matrix and ends with the job's exit from the shop.