| Sažetak | Kirurški postupak kojim se odstranjuje dio ili cijela štitnjača naziva se tireoidektomija. S obzirom na anatomsku blizinu štitnjače i struktura koje sudjeluju u proizvodnji govora, posebna pažnja tijekom postupka tireoidektomije se posvećuje očuvanju povratnog laringealnog živca s posljedičnim očuvanjem funkcije glasa, govora i gutanja. Usprkos niskom postotku pacijenata s ozljedom povratnog laringealnog živca nakon tireoidektomije (do 5%), vrlo visok postotak pacijenata (do 87%) ipak razvije poremećaj glasa. Promjene u glasu se javljaju iako se objektivnim pretragama ne pronalaze promjene na glasnicama, kako u strukturi, tako i u funkciji. Zbog učestalosti pojave poremećaja glasa, kojem je teško utvrditi uzrok nakon tireoidektomije, ova problematika je od iznimne znanstvene i praktične važnosti.
Prvi cilj ovog istraživanja bio je ispitati tijek oporavka glasa nakon tireoidektomije bez lezije povratnog laringealnog živca, u tri vremenske točke nakon operacije. Osim toga, ciljevi su bili ispitati korelate poremećaja glasa nakon tireoidektomije bez lezije povratnog laringealnog živca te ispitati odnos između kvalitete glasa i kvalitete života nakon tireoidektomije bez lezije povratnog laringealnog živca.
U istraživanju su sudjelovala 292 sudionika koji su bili podvrgnuti tireoidektomiji, a nisu razvili ozljedu povratnog laringealnog živca. Ozljeda je isključena primjenom videostroboskopije. Sudionici su praćeni kroz 4 vremenske točke: preoperativno, između 7 i 10 dana nakon operacije, 3 mjeseca nakon operacije i 6 mjeseci nakon operacije. Oni kojima se glas oporavio bili su isključeni iz sljedećeg mjerenja. U svim mjerenjima su se procjenjivale objektivne, perceptivne i subjektivne značajke glasa te kvaliteta života. Objektivne značajke su se mjerile akustičkom analizom koja je uključivala: fundamentalnu frekvenciju (F0), intenzitet, jitter, shimmer i maksimalno vrijeme fonacije (MVF). Perceptivne značajke su se mjerile ljestvicom GRBAS, a subjektivne VHI ljestvicom. Kvaliteta života se mjerila WHOQOL-BREF ljestvicom te su se koristile ukupna kvaliteta života, zadovoljstvo zdravljem, fizička i psihološka domena kvalitete života. Primijenjen je i sociodemografski upitnik.
Rezultati su pokazali da je čak 85% sudionika razvilo poremećaj glasa nakon tireoidektomije. Rezultati ANOVA-e na ponovljenim mjerenjima, primjenom LOCF metode, su pokazali statistički značajne razlike u kvaliteti objektivnih, perceptivnih i subjektivnih značajki glasa između tri postoperativna mjerenja, s konzistentnim trendom poboljšanja poremećaja glasa uvjetovanih tireoidektomijom. Korelacijska i regresijska analiza su pokazale da je kvaliteta glasa mjerena objektivnim, perceptivnim i subjektivnim mjerama značajno povezana i dobro predviđa ukupnu kvalitetu života, zadovoljstvo zdravljem te fizičku i psihološku domenu kvalitete života u sva tri postoperativna mjerenja. Niža kvaliteta glasa rezultirala je i nižom procjenom kvalitete života u ovim domenama. Vrsta i trajanje operacije, preoperativni volumen štitnjače te BMI sudionika pokazali su se važnim prediktorima brzine oporavka glasa, pri čemu su se sudionici podvrgnuti totalnoj tireoidektomiji (nasuprot lobektomiji), oni kod kojih je operacija duže trajala, oni s većim volumenom štitnjače i višim BMI-om oporavljali sporije. |
| Sažetak (engleski) | Introduction: In recent decades, the number of people with thyroid diseases requiring surgical treatment has been continuously growing. Thyroidectomy is a surgical procedure that removes part (lobectomy) or all of the thyroid gland (total thyroidectomy). Considering the anatomical proximity of the thyroid gland and the structures involved in speech production, special attention during the thyroidectomy procedure is devoted to the preservation of the recurrent laryngeal nerve with the consequent preservation of voice, speech and swallowing function. Despite the low percentage of patients with recurrent laryngeal nerve injury after thyroidectomy (up to 5%), a very high percentage of patients (up to 87%) still develop a voice disorder. Changes in the voice occur even though objective tests do not find changes in the vocal cords, both in structure and function. Longitudinal studies showed that, with time, most of the patients recover, however high percentage of patients (up to 18%) can have a voice disorder that persists even one year after thyroidectomy. Considering that voice has an important role in personal identity, a changed voice, especially if the condition is long-term, can cause increased anxiety and depression, lower the quality of life, and slow down the recovery process. Some of previously examined risk factors for voice disorder development and persistence include age, sex, cigarette and alcohol consumption, BMI, type of surgery, time of surgery and volume of thyroid gland before surgery, however results were inconsistent.
Due to the frequency of voice disorder occurrence after thyroidectomy, there is an exceptional scientific and practical importance of studying patients without visible vocal cords injuries. Therefore, the main aim of this study was to follow recovery of the voice disorder that developed without recurrent laryngeal nerve injury. The first objective was to examine the course of voice recovery at three time points after surgery: 7 to 10 days, 3 months, and 6 months after the surgery. Second objective were to examine relationship between voice quality and quality of life after thyroidectomy. Finally, third objective was to determine the correlates of voice disorders after thyroidectomy without recurrent laryngeal nerve lesion.
Methodology: Participants of the study were 292 patients who underwent thyroidectomy and did not develop an injury to the recurrent laryngeal nerve. Initial sample size was 350, but 58 participants were excluded due to voice disorder before surgery, recurrent laryngeal nerve and giving up. Recurrent laryngeal nerve injury was ruled out using videostroboscopy. Participants who entered the study were followed through 4 time points: preoperatively, between 7 and 10 days after the surgery, 3 months after the surgery, and 6 months after the surgery. Those whose voice recovered were excluded from the next measurement. In all measurements, objective, perceptive and subjective features of the voice, as well as quality of life were assessed. Objective features were measured by acoustic analysis that included Fundamental Frequency (F0), Intensity, Jitter, Shimmer and Maximum Phonation Time (MVF). Perceptive features were measured with the GRBAS scale, and subjective features with the Voice Handicap index (VHI) scale. Quality of life was measured by the WHOQOL-BREF questionnaire. Overall quality of life, health satisfaction, physical and psychological domains of quality of life were used. Besides that, a sociodemographic questionnaire, that included questions about age, sex, profession was also applied.
Results: The results showed that as many as 85% of the participants developed a voice disorder after thyroidectomy without recurrent laryngeal nerve injury. 3 months after surgery, 52% of participants still suffered from disorder, and 6 months after surgery, 22% of them still didn’t fully recover. The results of repeated measures ANOVA, using the LOCF (last observation carried forward) method, showed statistically significant differences in the quality of objective, perceptive and subjective features of the voice between the three postoperative time points, with a consistent trend of improvement in voice quality. Most of objective, perceptive, and subjective indicators of voice quality were significantly correlated with overall quality of life, health satisfaction, physical and psychological domains of quality of life in all three postoperative measurements. Also, those indicators proved to be significant predictors of all examined domains of life quality, with the highest level of prediction 3 months after surgery. The bigger changes in voice resulted with lower subjective quality of life in all observed domains. Type and duration of surgery, preoperative thyroid volume, and participants' BMI were found to be important predictors of the rate of voice recovery. Participants undergoing total thyroidectomy were recovering in a slower rate than participants that had lobectomy. Furthermore, longer surgery and bigger thyroid volume resulted with slower recovery of voice, as well as higher BMI.
Conclusion: Voice disorders are common after thyroid surgery even when there is no laryngeal nerve injury. Although, a significant improvement can be observed over the period of time, approximately one-fifth of patients who develop the disorder, have it even 6 months after the surgery. Voice disorder is significantly correlated with the overall quality of life, satisfaction with health, physical and psychological domains of life quality. The most important factors for the persistence od voice disorder relate to the type and duration of the surgery, while the preoperative thyroid volume and the patient's BMI had significant, but smaller effect. Results emphasize the need for more systematic research, and developing standardized protocols and methodology for studying voice disorders after thyroidectomy. Systematic study and consistent results are necessary first step in developing prevention and rehabilitation programs. |
