An objective assessment of voice production after radiation therapy for stage I squamous cell carcinoma of the glottis

Vocal function after vertical partial laryngectomy with glottic reconstruction by false vocal fold flap: durational and frequency measures

OBJECTIVE

Compare vocal function following vertical partial laryngectomy (VPL) with or without glottic reconstruction by false vocal fold (FVF) mucosal flap.

STUDY DESIGN

Twenty-seven patients with Tla squamous cell carcinoma (SCC) of the glottis were included in a prospective randomized clinical study. All patients were treated by frontolateral partial laryngectomy (FLPL). Glottic reconstruction with FVF mucosal flap was performed in 14 patients at the time of the FLPL, whereas 13 patients had standard FLPL.

METHODS

Objective voice assessment was based on computerized acoustic recordings performed before and 1 year after surgery. When possible, additional recordings were performed at 3 months, 6 months, and 2 years postoperatively. Incidence of postoperative granuloma and anterior neoglottic web were noted. Repeated analysis of variance (ANOVA) was used to compare the durational (maximum phonation time, speech rate) and frequency measurements (average fundamental frequency [Fo], standard deviation of Fo, jitter, shimmer, noise-to-harmonics ratio, degree of voice breaks) between patients with or without glottic reconstruction, postoperative granuloma, and anterior neoglottic web. Linear regression was used to study the evolution over time of the durational and frequency measurements.

RESULTS

Frequency measurements improved with time and were significantly better in patients treated with glottic reconstruction. In addition, glottic reconstruction decreased incidence of postoperative granuloma and anterior neoglottic web.

CONCLUSIONS

The FVF mucosal flap technique can improve vocal results in selected cases of Tla SCC of the glottis when FLPL is the adequate surgical treatment. false vocal folds; glottic reconstruction; vertical partial laryngectomy; vocal function.

Multidimensional assessment of voice characteristics after radiotherapy for early glottic cancer

OBJECTIVES/HYPOTHESIS

To assess voice characteristics of patients following radiotherapy for early glottic cancer through a multidimensional analysis protocol including vocal function and voice quality measures.

METHODS

Voice analyses were performed for 60 patients treated with radiotherapy (66 Gy/33 fractions, 60 Gy/30 fractions, or 60 Gy/25 fractions) for early T1 glottic cancer and 20 matched control speakers. There was a longitudinal group of 10 patients for whom data were collected before as well as 6 months and 2 years after radiation. Furthermore, data were collected for five separate groups of 10 patients each, before, 6 months after, 2 years after, 3 to 7 years after, and 7 to 10 years after radiation. Vocal function was investigated by means of videolaryngostroboscopy, phonetography, maximum phonation time, and phonation quotient measures. Voice quality was assessed by means of objective acoustical analysis and subjective perceptual ratings by trained raters.

RESULTS

Voice characteristics of patients were decreased before radiotherapy, improved after treatment, and became comparable to the voice characteristics of control speakers in at least 55% of the patients. Following radiotherapy, deviant voice quality was mainly negatively affected by increased age and stripping the vocal cord for initial diagnosis. Stroboscopy revealed that next to increasing age and stripping the vocal cord, continued smoking after treatment decreased vocal function following radiotherapy.

CONCLUSION

Voices of patients diagnosed with early glottic cancer improved but did not normalize fully after radiotherapy. Stripping the vocal cord for initial diagnosis and continued smoking after treatment decreased voice characteristics. A multidimensional analysis protocol including perceptual and acoustical analysis of voice quality and stroboscopic analysis of vocal function is recommended to investigate voice characteristics following treatment for early glottic cancer.

Phonatory results after laser surgery for glottic carcinoma

OBJECTIVE

To identify the influence of type and extent of surgery on postoperative voice parameters after endoscopic laser resection for glottic carcinoma.

SETTING AND DESIGN

A multidisciplinary university-based head and neck cancer center. Objective and subjective measures of voice were correlated with type and extent of surgery following a standardized classification in a prospective study including 80 patients.

SUBJECTS AND METHOD

The postoperative mechanism of phonation was assessed by videostroboscopy 6 months after surgery at the earliest. A phonetogram was produced, and its area was calculated (relative phonetogram (RP)) in relation to a gender-different normal phonetogram. Two speech therapists (ST) and a trained otolaryngologist (TO) rated each voice independently for communication ability in a grade from 1 (poor) to 5 (near normal).

RESULTS

After simple cordectomy the means were as follows: RP = 24.8%, TO = 3.26, and ST = 3.33. When the anterior commissure was completely preserved, mean results were better (RP = 34%, TO = 3.92, ST = 3.83). Results were worse after extended cordectomy (RP = 14.7%, TO = 2.82, ST = 3.00) and transglottic resection (RP = 13.7%, TO = 2.30, ST = 2.86) but were similar within these two groups. The parameters RP TO, and ST do not differ significantly between the group who had speech therapy after surgery (n = 33) and the group who did not (n = 47). Voice production at glottic level yields better results for every parameter than supraglottic substitute phonation. The amount of tissue removed was less significant.

CONCLUSION

Postoperative phonatory results correlate with the postoperative mechanism of phonation. There is no linear correlation with the amount of tissue removed. Comparison of similar types of resection preservation of the anterior commissure plays a key role. From the data in this study, there is no evidence for a significant benefit from speech therapy. The parameter RP is an effective and relatively simple parameter to complete auditory voice assessment.

Has radiotherapy become too expensive to be considered a treatment option for early glottic cancer?

BACKGROUND

External beam radiotherapy and surgery produce equivalent long-term survival and tumor control in early glottic cancer. The expense and cost of radiotherapy have been challenged.

METHODS

A retrospective review was performed for 57 patients undergoing radiotherapy for glottic cancer. End points included local tumor control, relapse-free survival, cause-specific survival, medical charges, and costs. The results were compared with those of 265 patients who underwent transoral endoscopic removal or an open laryngeal procedure at the same institution.

RESULTS

The local control, larynx preservation, re-treatment, voice quality, relapse-free survival, and cancer death results and medical charges and costs are reported by treatment.

CONCLUSIONS

Radiotherapy provides at least equivalent, if not superior, local tumor control, larynx preservation, voice quality, and survival, compared with the surgical options. Overall medical charges and costs for radiotherapy are similar to transoral endoscopic resection and less than partial vertical laryngectomy.

Objective evaluation of the quality of voice following radiation therapy for T1 glottic cancer

BACKGROUND

Radiation therapy is commonly considered the treatment of choice for T1 glottic cancer. While it is generally believed that the quality of voice following irradiation is quite satisfactory, few studies have reported the results of objective assessment of voice after radiation therapy.

PURPOSE

To objectively evaluate the quality of voice following radiation therapy for T1 glottic cancer.

MATERIALS AND METHODS

The voices of 12 patients treated for T1 glottic cancer with radiation therapy were evaluated by acoustic analysis and speech aerodynamic studies. Eleven patients received between 6300 and 6665 cGy at a daily fraction size of 180-225 cGy. One patient received 7000 cGy at a daily fraction size of 200 cGy. Evaluation of the quality of voice was done 3 months to 7 years following completion of radiation therapy.

RESULTS

The number of patients who scored abnormal values for the measurements of fundamental frequency, jitter, shimmer and harmonic to noise ratio was 2, 10, 4 and 3, respectively. The number of patients who scored abnormal values for transglottic airflow rate, subglottal pressure and glottal resistance was 12, 8 and 9, respectively. None of the studied patients scored normal values in all given tests.

CONCLUSION

Although radiation therapy cures a high proportion of patients with T1 glottic cancer, the quality of voice does not return to normal following treatment.

Premalignant lesions of the vocal cords. A retrospective study of 62 cases treated with CO2 laser

A series of 62 patients treated by (repeated) CO2 laser excision and/or vaporization for premalignant lesions of the vocal cords was analysed retrospectively. Of the 54 patients available for follow-up (ranging from 1 to 15 years), five patients (9%) developed an invasive glottic carcinoma and needed radiotherapy. Only two patients (4%) needed extensive surgery (total laryngectomy). One patient (2%) died of a recurrent carcinoma despite radiotherapy and laryngectomy, and six patients (11%) died of a metachronic lung carcinoma. The therapeutic results of (repeated) laser therapy were comparable to those in other reports regarding radiotherapy or stripping. The subjective functional results were satisfactory and tended to improve along with refinement of laser surgery techniques. Follow-up of patients who once had a premalignant laryngeal lesion is mandatory ad vitam, regardless of the grade of the lesion. For the screening of lung cancer, there is still no consensus on a standard-of-care. The classical chest X-ray remains the most accessible and comfortable screening procedure.

Temperature distribution in expiratory speaking flow, and early detection of vocal fold pathology

This paper describes an application of heat transfer fundamentals to the development and testing of an instrument with potential use for speech production analysis. The method exploits an assumed difference between the air flow patterns of individuals with healthy and breathy voices: during breathy speech production, the glottis does not close completely, and the leakage of warm air through the glottis increases the extent of the temperature field outside the oral cavity. The proposed instrument is a pipe through which the tested individual breathes out while producing a sustained vowel. The pipe wall temperature is maintained uniform at a level considerably lower than the body temperature. The temperature gradient along the pipe centreline is measured and related to the average air velocity through the glottis. The measurements compare favourably with numerical results for the temperature field inside the instrument. These findings therefore suggest that the temperature distribution outside the oral cavity could be useful in understanding changes in air flow patterns through the vocal folds. The centreline temperature chart to be used in conjunction with the instrument is reported in dimensionless terms.

Acoustic analysis of voice in individuals with amyotrophic lateral sclerosis and perceptually normal vocal quality

Currently, early phonatory changes in amyotrophic lateral sclerosis (ALS) are not well understood. The aim of this study was to compare acoustic parameters of voice in ALS subjects who demonstrated perceptually normal vocal quality on sustained phonation with a control group. We hypothesized that objective analysis of voice would reveal significant differences on specific acoustic parameters of voice compared to the control group. Results revealed statistically significant differences between the two groups on measures related to frequency range and phonatory stability. The findings suggest that early bulbar signs affecting the laryngeal system may be present in patients with ALS before the occurrence of perceptually aberrant vocal characteristics.

Quantitative analysis of voice quality in early glottic laryngeal carcinomas treated with radiotherapy

The quality of voice after radiotherapy is generally considered to be better than that after surgery for early glottic (T1a and T1b) carcinomas. Studies concerning voice quality after radiotherapy are scarce, and results have been contradictory concerning actual normalization of voice following therapy. This study was designed to compare several voice parameters of patients successfully treated 1-12 years previously with radiotherapy (5750-7000 cGy) for early glottic carcinoma. Parameters involved an age- and sex-matched control group. Results showed that voice quality following radiotherapy was less than normal for maximum vocal intensity, dynamic vocal intensity range, jitter, and mean fundamental frequency. These findings showed that voice following radiotherapy could not be considered normal.

Stroboscopic observation of the larynx after radiation in patients with T1 glottic carcinoma

We studied laryngeal video stroboscopy (LVS) system for evaluation of patients with glottic carcinoma (T1N0M0) before and after radiotherapy. There were 10 patients with T1 glottic squamous cell carcinoma (9 men and 1 woman) who received radiotherapy at the Hitachi General Hospital. We performed LVS before and after radiotherapy. The presence or absence of mucosal waves (MW) was particularly noted. No MW were present before radiotherapy but at 1-6 months after, MW gradually appeared. One year after radiotherapy all patients showed MW on LVS. In patients with glottic carcinoma MW recovered after radiation therapy. LVS may be useful for the clinical follow-up of post-radiation patients for early detection of recurrence of glottic carcinoma.

Phonomicrosurgical treatment of early glottic cancer and carcinoma in situ

BACKGROUND

In recent years, transoral resection of early glottic cancer has developed into a phonomicrosurgical approach that resulted from the convergence of microlaryngoscopic surgical technique theory with body cover mucosal wave theory of voice production. The vocal outcome from these procedures has improved by minimizing the deep resection margin and thereby maximizing the preservation of the vocal folds' normal layered microstructure (laminae propria and epithelium). Recurrence and cure rates from this narrow-margin approach were examined.

METHODS

The phonomicrosurgical resection approach is composed of four basic procedures in which there is an increasing depth of resection to accommodate a narrow-field deep cancer margin. This approach was employed to treat 13 T1 cancers and 7 with carcinoma in situ (CIS).

RESULTS

No patients who underwent a cancer resection developed a recurrence. Minimum follow-up on these patients was 2 years and the mean follow-up was 42 months. In the group with CIS, 2 patients developed microinvasive carcinoma despite en bloc excision of the CIS. Both were successfully treated; 1 was resected transorally and the other underwent radiation therapy.

CONCLUSIONS

This study indicates that the phonomicrosurgical approach, which incorporates a narrow deep cancer margin to enhance the postoperative vocal outcome, resulted in standard control and cure of early glottic neoplasia.

Direct speech feature estimation using an iterative EM algorithm for vocal fold pathology detection

The focus of this study is to formulate a speech parameter estimation algorithm for analysis/detection of vocal fold pathology. The speech processing algorithm proposed estimates features necessary to formulate a stochastic model to characterize healthy and pathology conditions from speech recordings. The general idea is to separate speech components under healthy and assumed pathology conditions. This problem is addressed using an iterative maximum-likelihood (ML) estimation procedure, based on the estimation-maximization (EM) algorithm. A new feature for characterizing pathology, termed enhanced-spectral-pathology component (ESPC), is estimated and shown to vary consistently between healthy and pathology conditions. It is also shown that the mean-area-peak-value (MAPV) and the weighted-slope (WSLOPE) indexes, which are obtained from the ESPC estimate, are meaningful measures of speech pathology conditions. For classification purposes, a five-state hidden-Markov-model (HMM) recognizer was formulated, based on the MAPV, WSLOPE, and ESPC spectral features. A set of log Mel-frequency filter bank coefficients were used to parameterize the ESPC feature. An evaluation of the HMM-based classifier was performed using speech recordings from healthy and vocal fold cancer patients of sustained vowel sounds. It is shown that while both MAPV and WSLOPE are useful features for vocal fold pathology detection, superior performance was achieved using a finer spectral representation of ESPC (e.g., a detection rate of 88.7% for pathology and 92.8% for healthy condition). One main advantage of the proposed method is that it does not require direct estimation of the glottal flow waveform. Therefore, the limitation of the inability to characterize vocal fold pathology, due to incomplete glottal closure, is no longer an issue. The results suggest that general analysis of the ESPC feature can provide a quantitative, noninvasive approach for analysis, detection, and characterization of speech production under vocal fold pathology.

Voice evaluation before and after laser excision vs. radiotherapy of T1A glottic carcinoma

Quality of voice after treatment for T1A glottic squamous cell carcinoma was studied in two matched groups of males treated either with CO2 laser cordectomi (n = 18, mean age 65.2 years) or with full dose radiotherapy (n = 18, mean age 65.1 years). All patients had histologically verified invasive squamous cell carcinoma. Fifteen male patients (mean age 63.9 years) without laryngeal disorders were used as controls. Voice recordings prior to treatment, and both at 3 months and at 2 years after completed treatment were analyzed. Acoustic measures of shimmer, jitter, breathiness, harmonic-to-noise ratio and fundamental frequency (F0) average were calculated with the Soundscope program. Two plain measures were also used: time required to read a running speech voice sample, and number of breaths. Perceptual voice analysis was performed blindly by two groups of listeners, Group A (4 experienced listeners) and Group B (4 naive listeners). Group A estimated quality of voice according to a modified GRBAS score, whereas Group B estimated Grade only. We found voice quality both at 3 months and at 2 years after radiotherapy to be significantly better than after laser treatment, as assessed by the acoustic variables breathiness, jitter, F0 average, running speech voice sample reading time and number of breaths. The perceptual variables Grade (Group A and B), Breathiness, Asthenia and Strain were also significantly better after radiotherapy.

Premalignant epithelium and microinvasive cancer of the vocal fold: the evolution of phonomicrosurgical management

Phonomicrosurgical treatment of premalignant vocal fold epithelium and microinvasive cancer combines principles of surgical oncology with advanced laryngoscopic microsurgical-techniques. This treatment is guided by mucosal-wave theory of voice production and strives not only to cure the disease but also to achieve optimal vocal function. Surgical techniques developed during the past two centuries have improved methods for vocal fold visualization, tissue retrieval, and tissue evaluation. Examination of the evolution of these surgical techniques reveals the incomplete convergence of laryngoscopic surgical theory with both the concept of premalignancy and the anatomical-physiological principles of voice production. This historical review, which helps to explain the lack of consensus about current treatment options, led to a series of four investigations. They were conducted with the aim of developing a laryngoscopic (phonomicrosurgical) management approach for improving the treatment of premalignant and microinvasive vocal fold epithelium. In the first of four investigations, 42 patients (each of whom had a significant smoking history) underwent microlaryngoscopic biopsy of 52 vocal fold lesions. These lesions, which were suspicious for atypia or malignancy and were confined to the musculomembranous vocal fold, were mapped according to surface involvement and depth of penetration. Review of the maps revealed that 27 of the 52 lesions involved only the superior/ventricular surface. For these patients, the entire layered vocal fold structure could potentially be preserved on the medial/vocalizing surface. Twenty-five of the 52 lesions involved both the superior/ventricular surface and the medial/vocalizing surface. No lesion involved only the medial surface. These data suggest that (in smokers) geographic localization of keratotic and erythroplastic lesions on the superior/ventricular surface of the musculomembranous vocal fold are likely to contain atypia. This characteristic facilitates the appropriate selection of patients for biopsy and may spare individuals, who have lesions resulting from hyperfunctional dysphonia and/or gastroesophageal reflux, from unnecessary biopsy. These two disorders typically result in pathology on the medial and/or posterior glottal surfaces. In order to determine whether a directed biopsy or an excisional biopsy approach is preferable for obtaining an accurate diagnosis, all specimens underwent whole-mount sectioning for three-dimensional histopathological analysis. Keratosis was noted: without atypia in 14; with atypia in 27; and with carcinoma in 11. The severity of the atypia usually varied throughout each specimen. The surface appearance of the lesion was not a reliable prognosticator of the severity of dysplasia either between patients or in different areas of the same lesion; therefore, excisional biopsy and whole-mount, multiple-section histopathological analysis were necessary for obtaining an accurate diagnosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Aerodynamic and stroboscopic findings before and after microlaryngeal phonosurgery

Acoustic, aerodynamic, and laryngo-video-stroboscopy (LVS) studies were done on 50 patients before and after microlaryngeal surgery for benign vocal fold lesions. Perceptual pre- and postratings were also obtained. After microlaryngeal surgery, statistically significant differences between pre- and posttreatment conditions included postoperative findings of (a) a lowering of mean flow rate, (b) an increase in glottal efficiency, and (c) an increase in maximum sound pressure level. There was no significant improvement in maximum phonation time. Stroboscopy findings showed changes of glottal configuration, linearity of the vocal fold edge, amplitude of vocal fold vibration, excursion of the mucosal wave, and periodicity. Acceptable perceptual voice quality appeared to depend on a straight vocal fold edge, good vibratory amplitude, and good mucosal wave. Improved understanding of vocal function after phonosurgery should help us refine surgical principles and techniques. The combined use of LVS and phonatory function measures is advocated.

Laser cordectomy or radiotherapy: cure rates, communication, and cost

Health care costs have risen dramatically in recent years. Cost-containment strategies have become necessary to ensure that adequate medical care is accessible to all who need it. These strategies include choosing the least costly of several treatment modalities with equal efficacy. Radiotherapy has been considered by some as the treatment of choice for early glottic tumors. Rationale for this is based on two major assumptions: that cure rates are equal for radiotherapy and surgery, and that voice preservation and quality is superior with radiotherapy. Implicit in these assumptions is the idea that cost of therapy should not be a factor in selecting an alternative. This study presents a literature review of cure rates for laser cordectomy and radiotherapy for T1 glottic cancers. An objective voice analysis was performed on 14 patients with T1 glottic cancers treated with laser cordectomy and the results were compared to a group of 20 patients treated with radiotherapy for similar early tumors. Finally, the average total cost of each modality was calculated and compared. Our findings indicate that: (1) cure rates are equivalent; (2) voice quality after laser cordectomy is as good as that noted after radiotherapy; and (3) total cost of therapy is much less for laser cordectomy than for radiotherapy. We advocate laser cordectomy rather than radiotherapy for most early glottic tumors.

Voice analysis of patients with endoscopically treated early laryngeal carcinoma

Endoscopic laser resection of early (T1) laryngeal carcinoma has been advocated as an alternative to radiotherapy. Heretofore, the voice characteristics following this procedure have been addressed in only one review, which included patients treated by irradiation and laser resection. We present the first review of voice findings in 22 patients treated only by endoscopic laser resection of their vocal cord carcinomas. Laser resection of selected vocal cord carcinomas produced voice function results acceptable to the patients and was rated by them to be normal to almost normal. Speech pathologists rated the voices to be near-normal to mildly abnormal. Voices after laser resection of vocal carcinoma exhibited a slightly higher fundamental frequency, a decrease in intensity and phonatory duration, and markedly higher laryngeal airway resistance. The percentage of voicing showed little deviation from normal, as did mean percentage of perturbations.

The effect of laryngeal irradiation on pharyngoesophageal motility

The upper esophageal sphincter (UES) receives the full radiation dose during external beam radiotherapy to the adjacent larynx. The aim of the study was to assess the effects, if any, of radical laryngeal radiotherapy on motility patterns in the pharyngoesophageal segment. A strain gauge assembly and a digital manometric recorder were used to assess 19 patients 13 to 71 months after irradiation of T1 to T3 glottic cancer to a central dose of 52.5 to 55.7 Gy in 20 daily fractions. Results were compared with those of 23 healthy controls. Tonic lower esophageal sphincter (LES) pressure, distal peristaltic contraction, tonic UES pressure, and eight parameters of pharyngoesophageal dynamics during water and bread swallows were studied. No difference was found between the two groups in tonic LES pressure, peristaltic amplitude, or tonic UES pressure. Water swallow pharyngoesophageal wave velocity was significantly lower in patients than in controls, and the irradiated group also showed a trend toward increased duration of the distal esophageal peristaltic wave. The reduction in upper esophageal wave velocity was associated with the interval following irradiation. The post-treatment interval was also inversely related to the amplitude of UES after-contraction, and associated with an increase in wave duration throughout the pharyngoesophageal segment. A study of 23 laryngectomy specimens, 5 of which had been removed following radiotherapy, failed to identify pathological features in nerves or muscle which characterised previous laryngopharyngeal irradiation. We conclude that laryngeal irradiation has no effect on upper or lower esophageal sphincter tone but causes an increase in wave duration and a reduction in wave velocity in the pharyngoesophageal segment. These changes are independent of age and sex and are not associated with pathological features like the neural degeneration described in the myenteric plexus of irradiated rectum.

Radical radiotherapy for carcinoma of the larynx--Westmead Hospital experience

Between January 1980 and December 1988, 141 patients were treated with radical radiotherapy for carcinoma of the larynx. One hundred and ten (78%) tumours arose on the vocal cords, twenty nine (21%) from the supraglottis and two (1%) from the subglottis. All 63 stage T1 cases, and all except three of 62 T2 cases seen in the time period, were treated by radiotherapy. In addition 14 selected T3 and 5 T4 cases were irradiated. Only 7% had clinical evidence of regional lymph node metastases at presentation. Median follow up is 47.5 months and 2+ year actuarial local control rates are T1-87%, T2-63%, T3-79% and T4-53%. The rates for vocal cord primaries are T1-86%, T2-58%, and T3-75%. Median time to local failure was 8 months with none occurring beyond 21 months. Two of 130 N0 cases (1.5%) relapsed in cervical lymph nodes with a policy of selective prophylactic irradiation of the regional lymphatic areas. Thirty three/thirty seven patients with locoregional failure underwent salvage surgery with 27/32 (84%) evaluable patients achieving ultimate locoregional control with median follow up of 18.5 months from salvage. Four patients (3%) developed distant metastases and 21 (15%) developed a second primary malignancy (including 13 lung cancers) with an actuarial rate of second primary tumours of 23% at five years. Three year actuarial survival for the whole group is 77% but 66% of deaths were due to causes other than larynx cancer. Tumour specific mortality by stage is T1-1.6%, T2-12%, T3,4-21%.(ABSTRACT TRUNCATED AT 250 WORDS)

Laryngeal pathology in hearing-impaired children

Eighty-five children enrolled in a total communication elementary school for the severe-to-profoundly hearing-impaired were evaluated prospectively to assess the incidence of laryngeal abnormalities. Direct flexible laryngoscopy and indirect mirror laryngoscopy revealed vocal cord nodules in 3 children, omega-shape infantile epiglottis in 3 children, and normal larynges in the remaining 79 children. These findings suggest that severe-to-profoundly hearing-impaired children develop detectable laryngeal pathology at approximately the same frequency as previously reported by others for normal hearing children.

Endoscopic laser surgery for early glottic carcinoma: a clinical and experimental study

The purpose of this study is to define the indications for using the CO2 laser for the treatment of early glottic cancer. For this purpose, 52 consecutive laser resections of Tis to T2 vocal cord carcinomas were studied prospectively. In addition, laser resection was performed in eight human cadaver larynges, which were then examined histologically using whole organ sections. Both tumor size and tumor location had important influences on tumor resectability by laser. All of the Tis, 78% of T1, and one of four T2 carcinomas were successfully treated by laser surgery alone. Of the 10 carcinomas involving the anterior commissure, only four could completely be resected with the laser; of these four, two recurred in the anterior commissure. This finding is corroborated by the histologic study, which clearly shows that anterior commissure resection poses problems. The only laser resection complication of early glottic cancer was persistent hoarseness in one third of the patients. It is concluded that CO2 laser resection is a safe and effective alternative treatment for patients with Tis and T1 glottic carcinoma, provided the anterior commissure is free of tumor.