Partial or conservation laryngectomy procedures are performed not only to surgically remove a malignant lesion from the larynx, but also to preserve some functional valving capacity of the laryngeal mechanism. Retention of adequate valvular function allows conservation of some degree of vocal function and safe swallowing. As such, the primary goal of conservation laryngectomy procedures is cancer control and oncologic safety, with a secondary goal of maintaining upper airway sphincteric function and phonatory capacity postsurgery. However, conservation laryngectomy will always necessitate tissue ablation, with disruption of the vibratory integrity of at least one vocal fold (Bailey, 1981). From the standpoint of voice production, any degree of laryngeal tissue ablation has direct and potentially highly negative implications for the functional capacity of the postoperative larynx. Changes in laryngeal structure result in aerodynamic, vibratory, and ultimately acoustic changes in the voice signal (Berke, Gerratt, and Hanson, 1983; Rizer, Schecter, and Coleman, 1984; Doyle, 1994).

Vocal characteristics following conservation laryngectomy are a consequence of anatomical influences and the resultant physiological function of the postsurgical laryngeal sphincter, as well as secondary physiological compensation. In some instances, this level of compensation may facilitate the communicative process, but in other instances such compensations may be detrimental to the speaker's communicative effectiveness (Doyle, 1997). Perceptual observations following a variety of conservation laryngectomy procedures have been diverse, but data clearly indicate perceived changes in voice quality, the degree of air leakage through the reconstructed laryngeal sphincter, the appearance of compensatory hypervalving, and other features (Blaugrund et al., 1984; Leeper, Heeneman, and Reynolds, 1990; Hoasjoe et al., 1992; Doyle et al., 1995; Keith, Leeper, and Doyle, 1996). Two factors in particular, glottic insufficiency and the relative degree of compliance and resistance to airflow offered by the reconstructed valve, appear to play a significant role in compensatory behaviors influencing auditory-perceptual assessments of voice quality (Doyle, 1997). Excessive closure of the laryngeal mechanism at either glottic or supraglottic (or both) levels might decrease air escape, but may also create abnormalities in voice quality due to active (volitional) hyperclosure (Leeper, Heeneman, and Reynolds, 1990; Doyle et al., 1995; Keith, Leeper, and Doyle, 1996; Doyle, 1997). Similarly, volitional, compensatory adjustments in respiratory volume in an effort to drive a noncompliant voicing source characterized by postsurgical increases in its resistance to airflow may negatively influence auditory-perceptual judgments of the voice by listeners. This may then call attention to the voice, with varied degrees of social penalty. In this regard, the ultimate postsurgical effects of conservation laryngectomy on voice quality may result in unique limitations for men and women, and as such require clinical consideration.

The clinical evaluation of individuals who have undergone conservation laryngectomy initially focuses on identifying behaviors that hold the greatest potential to negatively alter voice quality. Excessive vocal effort and a harsh, strained voice quality are commonly observed (Doyle et al., 1995). Standard evaluation may include videoendoscopy (via both rigid and flexible endoscopy) and acoustic, aerodynamic, and auditory-perceptual assessment. Until recently, only limited comprehensive data on vocal characteristics of those undergoing conservation laryngectomy have been available. Careful, systematic perceptual assessment has direct clinical implications in that information from such an assessment will lead to the definition of treatment goals and methods of monitoring potential progress. A comprehensive framework for the evaluation and treatment of voice alterations in those who have undergone conservation laryngectomy is available (Doyle, 1977).

Depending on the auditory-perceptual character of the voice, the clinician should be able to discern functional (physiological) changes to the sphincter that may have a direct influence on voice quality. Those auditory_-perceptual features that most negatively affect overall voice quality should form the initial targets for therapeutic intervention. For example, the speaker's attempt to increase vocal loudness may create a level of hyperclosure that is detrimental to judgments of voice quality. Although the rationale for such “abnormal” behavior is easily understood, the speaker must understand the relative levels of penalty it creates in a communicative context. Further treatment goals should focus on (1) enhancing residual vocal functions and capacities, and (2) efforts to reduce or eliminate compensatory behaviors that negatively alter the voice signal (Doyle, 1997). Thus, primary treatment targets will frequently address changes in voice quality and/or vocal effort. Increased effort may be compensatory in an attempt to alter pitch or loudness, or simply to initiate the generation of voice. Clinical assessment should determine whether voice change is due to under_-or overcompensation for the disrupted sphincter. Therefore, strategies for voice therapy must address changes in anatomical and physiological function, the contributions of volitional compensation, and whether changes in voice quality may be the result of multiple factors.

Voice therapy strategics for those who have undergone conservation laryngectomy have evolved from strategics used in traditional voice therapy (e.g., Colton and Casper, 1990; Boone and McFarland, 1994). Doyle (1997) has suggested that therapy following conservation laryngectomy should focus on “(1) smooth and easy phonation; (2) a slow, productive transition to voice generation at the initiation of voice and speech production, (3) increasing the length of utterance in conjunction with consistently easy phonation, and (4) control of speech rate via phrasing.” The intent is to improve vocal efficiency and generate the best voice quality without excessive physical effort. Clinical goals that focus on “easy” voice production without excessive speech rate are appropriate targets. Common facilitation methods may involve the use of visual or auditory feedback, ear training, and respiration training (Boone, 1977; Boone and McFarland, 1994; Doyle, 1997).

Maladaptive compensations following conservation laryngectomy often tend to be hyperfunctional behaviors. However, a subgroup of individuals may present with weak and inaudible voices because of pain or discomfort in the early postsurgical period. Such compensations may remain when the discomfort has resolved, and may result in perceptible limitations in verbal communication. In such cases of hypofunctional behavior, voice therapy is usually directed toward facilitating increased approximation of the laryngeal valve by means of traditional voice therapy methods (Boone, 1977; Colton and Casper, 1990). A weak voice requires the clinician to orient therapy tasks toward systematically increasing glottal resistance. Although a “rough” or “effortful” voice may be judged as abnormal, it may be preferable for some speakers when compared to a breathy voice quality. This is of particular importance when evaluating goals and potential voice outcomes relative to the speaker's sex.

The physical and psychological demands placed on the patient during initial attempts at voicing might increase levels of tension that ultimately may reduce the individual's phonatory capability. Those individuals who exhibit increased fundamental frequency, excessively aperiodic voices, or intermittent voice stoppages may be experiencing problems that result from postoperative physiological overcompensation because they are struggling to produce voice. Many individuals who have undergone conservative laryngectomy may demonstrate considerable effort during attempts at postsurgical voice production, particularly early during treatment. Because active glottic hypofunction is infrequently noted in those who have undergone conservative laryngectomy, clinical tasks that focus on reducing overcompensation (i.e., hyperfunctional closure) are more commonly used.

See also laryngectomy.