T1b声門癌CO<SUB>2</SUB>レーザー手術

Abstract

Phonatory functions were compared among 25 patients with T1 glottic cancer (T1a : 18, T1b : 7) following the combined therapy of laser and radiation, 9 patients with T1-2 following radiation treatment alone, and 40 normal subjects (over 50 years old). Maximum phonation time (sec), air flow rate (ml/sec), vocal velocity index, pitch (Hz), pitch perturbation quotient (%), amplitude perturbation quotient (%), and normalized noise energy (dB) were obtained from the use of a phonatory equipment PS-77 and an acoustic analyser SH-10.Moreover, phonatory dysfunctions in 6 of 7 patients with T1b glottic cancer were estimated on the basis of extent and depth of laser irradiation, and of post-operative laryngeal findings by fiberscope.The results were as follows.1. The mean values of phonatory parameters in normal subjects were MPT : 17.8 sec, AFR : 187 ml/sec, VVI : 45.5, pitch : 147 Hz, PPQ : 1.01%, APQ : 3.34%, and NNE : -11.1 dB respectively.In comparison with the normal subjects, those values of radiation treatment alone coinsided closely, and those of T1 group indicated distinctly a decline of the aerodynamic functions and a change for the worse of the acoustic characteristics of voices. However, the difference of those parameters were statistically no significant between Tla and Tlb group.2. After CO2 laser surgery for T1b, laryngoscopy revealed web formation of the anterior commissure (28%), asynmetry and fibrosis of all affected vocal cords. Degree of the post-operative changes had been affected by the extent more than the depth of laser irradiation in glottis.3. In T1b group, the mean values of phonatory parameters in the 3 patients with a marked postoperative change were a short MPT (6.2 sec), higher AFR (372 ml/sec) and VVI (104.3), and pitch : 225 Hz, PPQ : 1.79%, APQ : 4.00%, NNE : -5.6 dB, while, those in the 3 with a mild change were MPT : 18.0 sec, AFR : 155 ml/sec, VVI : 34.1, pitch : 146 Hz, PPQ : 0.25%, APQ : 2.56%, NNE : -14.2 dB, respectively.Because of having the lesion in both vocal cords, CO2 laser management for T1b glottic cancer has including more complex problems than that for T1a in the insure of favorable post-operative voices. At least, laser irradiation covered wide range of the bilateral vocal cords may be phonetically disadvantage. In the use of CO2 laser, it is a necessary to control adequately the extent of laser irradiation in a combination with radiation therapy of curative dose.