QUANTIFICATION OF DYNAMIC VELOPHARYNGEAL PORT EXCURSION FOLLOWING SPHINCTER PHARYNGOPLASTY

The sphincter pharyngoplasty is a surgical procedure designed to corre ct velopharyngeal dysfunction. Its advocates cite the theoretical adva ntage of its induction of dynamic activity of the neovelopharyngeal po rt, but this dynamic activity has yet to be quantitatively demonstrate d in the literature. The purpose of this study was to quantify postope rative velopharyngeal dynamism and to document tile results of interve ntion outcome on sphincteric excursion measurements from minimal-to-ma ximal orifice closure. We conducted a 7-year retrospective review of s peech videofluoroscopy evaluations in patients who had undergone sphin cter pharyngoplasty in our center. Between 1989 and 1994, there were 5 8 patients so treated for post-palatoplasty velopharyngeal dysfunction by two surgeons using the same operative technique. Patients for whom sphincter pharyngoplasty was recommended fulfilled both of the follow ing criteria: (1) velopharyngeal dysfunction caused by an anatomic, my oneural, or combined deficiency of the velopharyngeal sphincter that w ould not be expected to be managed by speech therapy alone, and (2) pr eoperative videonasendoscopy and speech videofluoroscopic studies that demonstrated large-gap coronal, circular, or bow-tie closure patterns or velopharyngeal hypodynamism. Of the original 58 patients, 24 under went postoperative speech videofluoroscopic evaluations with basal vie ws. Of these, 20 of the evaluations (83 percent) were of adequate qual ity to be included in a research study. Still images showing maximum a nd minimum excursion of the sphincter in basal view were obtained. To test for observer reliability, the speech videofluoroscopic studies we re randomized and presented for measurement to the same individual on two occasions, each session separated by a 1-month time interval. Topo graphic imaging software was used to obtain maximum and minimum measur ements to within 0.1 mm. Partitioning the variance of the data showed that measurement variability was a very small portion of the total, an d that difference between the minimum and maximum values was the large st sour ce of variability. Of the total variability in the data, 64.0 percent originated in the minimum/maximum difference, 34.3 percent cam e from patient variability, and only 1.7 percent resulted from origina l or repeat measurements. The patient variability may be exaggerated b ecause of variability in the scale of measurement. Results of this stu dy indicate a quantifiable and statistically significant difference in maximum-to-minimum excursion of sphincteric closure. Sphincter pharyn goplasty appears to be dynamic in the majority of cases.