HSC Section 6 Nov2016 Green Book

TABLE I. Univariable Analysis of Influencing Factors on the Surgical Outcome of Laryngeal Reinnervation.

Overall Grade

Jitter

Shimmer

NHR

MPT

Post-VMUR

Glottal Closure

< 0.001 < 0.001 < 0.001

Sex

0.7131

0.1844

0.1394

0.3456 0.0010 0.1554

0.1804

0.5141

< 0.001 < 0.001

< 0.001

< 0.001 < 0.001

< 0.001 < 0.001

Age

0.3441 0.3807

Pre-VMUR

0.0630

0.0022

< 0.001

< 0.001

< 0.001

0.0007

0.0010

Denervation duration

0.5410

Data in Table I represent P value calculated by univariable analysis. P < 0.05 is deemed as statistically significant. MPT 5 maximum phonation time; NHR 5 noise-to-harmonics ratio; VMUR 5 voluntary motor-unit recruitment.

the identified significant variables—denervation dura- tion. The results are as follows (see Table III).

analyses before building the multivariable logistic regression model. Univariable logistic regression models containing each covariate were fit. Covariates of known clinical significance or with P value < 0.05 in the univariable logistic models were selected as candidates for the multivariable model. Statistical significance was considered a -level 0.05.

Videostroboscopic Findings On preoperative videostroboscopy, the majority of cases in each group had severely incomplete glottal clo- sure, which did not differ significantly among the three groups. On videostroboscopy performed 2 years after the reinnervation operation, most patients showed complete glottal closure. The postoperative stroboscopic findings were significantly improved in total sample and within each group compared with the corresponding preopera- tive findings ( P < 0.01). However, denervation duration was not a significant variable with regard to multivari- able logistic regression analysis in glottal closure. Vocal Function Assessment The preoperative values of perceptual evaluation parameter (overall grade) and acoustic parameters—jit- ter (local), shimmer (local), and the NHR—showed no significant differences among the three groups. Two years after the reinnervation operation, the postopera- tive value of overall grade was significantly improved within each of the three groups compared with the corre- sponding preoperative values ( P < 0.001). Postoperative values of jitter (local), shimmer (local), and the NHR were significantly lower within each group compared with the corresponding preoperative values ( P < 0.05). The postoperative MPT was significantly longer than the preoperative MPT in each group ( P < 0.05). Denervation duration was identified as a significant variable with regard to parameters (overall grade), jitter, shimmer, NHR, and MPT in multivariable logistic

RESULTS Univariable Results

Table I displays the results of demographic or pre- operative medical variables in univariable analysis. Briefly, gender was only significantly associated with MPT. Age was significantly associated with overall grade, shimmer, NHR, MPT, postoperative VMUR, and glottal closure. Preoperative VMUR was significantly associated with overall grade, MPT, postoperative VMUR, and glottal closure, whereas denervation dura- tion was significantly associated with overall grade, jit- ter, shimmer, NHR, MPT, and postoperative VMUR. Multivariable Logistic Regression Model Results Based on univariable logistic regression results, sig- nificant candidate variables were identified ( P < 0.05) for assessment in the multivariable logistic regression model. Table II shows the results of multivariable logis- tic regression. These indicate that age of patients; sever- ity of nerve injury, which was presented as preoperative VMUR; and denervation duration had impact on the sur- gical effect of laryngeal reinnervation. Stratification analysis on other significant variables such as age of patients and preoperative VMUR will be presented in another report (unpublished). In the present study, we performed further stratification analysis aimed at one of

TABLE II. Multivariable Analysis of Influencing Factors on the Surgical Outcome of Laryngeal Reinnervation.

Overall Grade

Jitter

Shimmer

NHR

MPT

Post-VMUR

Glottal Closure

< 0.001 < 0.001 < 0.001 < 0.001

0.0133

Sex

0.6692

0.1124

0.2320

0.4301 0.0080

0.7663 0.0004

< 0.001 < 0.001 < 0.001

< 0.001

< 0.001

Age

0.2588 0.3374

< 0.001

< 0.001

0.0091

Pre-VMUR

0.4935

< 0.001

< 0.001

< 0.001

0.0004

Duration of denervation

0.1809

Data represent P value calculated by multivariable analysis. P < 0.05 is deemed as statistically significant. MPT 5 maximum phonation time; NHR 5 noise-to-harmonics ratio; VMUR 5 voluntary motor-unit recruitment.

Laryngoscope 124: August 2014

Li et al.: Denervated Duration on Reinnervation for UVFP

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