HSC Section 6 Nov2016 Green Book

TABLE I. Objective Measures and Definitions for a Dynamic Videofluoroscopic Swallow Study.

Objective Measures on Dynamic Videofluoroscopic Swallow Study (DSS)

Definition

Total pharyngeal transit time (TPT)

The time between the head of the bolus passing the posterior nasal spine to the time the tail of the bolus passes through the UES. UES opening. The narrowest point of opening between C3 and C6 during maximal distention for bolus passage. A surrogate measure of pharyngeal strength. Specifically, a ratio of pharyngeal area measured in lateral fluoroscopic view at the point of maximal pharyngeal constriction during the swallow to the pharyngeal area measured with the bolus held in the oral cavity. The difference in distance between the anterior margin of the hyoid bone with a 1cc bolus held in the oral cavity to maximal approximation of the hyoid and larynx during swallow and maximal hyoid to larynx approximation. A clear and consistently visible landmark on the anterior thyroid cartilage, such as calcification, was used as an alternative to the subglottic air column if it could not easily be visualized. Maximal approximation usually occurred just after maximal hyoid excursion. The distance traveled by the hyoid to the point of maximal elevation during a swallow from its position during hold.

Upper esophageal sphincter opening (UESmax)

Pharyngeal constriction ratio (PCR)

Hyoid to larynx approximation (HLx)

Hyoid excursion (Hmax)

sensation as a contributing factor to aspiration. 5 Other studies have provided evidence to support the notion that aspiration may not be solely related to vocal fold immobility, as demonstrated by continued dysphagia and/or aspiration after patients underwent surgical intervention to improve glottic closure. 6,7 There have yet to be objective kinematic and temporal measurements obtained from patients with subjective dysphagia as a result of UVFI related solely to vagus nerve injury. The purpose of this investigation was to evaluate pharyngeal strength and upper esophageal sphincter (UES) opening in individuals with UVFI caused by idiopathic or iatro- genic injuries to the vagus nerve. MATERIALS AND METHODS A clinical swallowing database consisting of individuals with dysphagia who underwent a dynamic videofluoroscopic swallow study (DSS) was reviewed to identify individuals with UVFI between January 1, 1999, and June 1, 2012. The Institu- tional Review Board of the University of California, Davis, approved use of this database for clinical research. All patients with UVFI were confirmed by videolaryngoscopy and/or strobo- videolaryngoscopy. Individuals were excluded if they were under 18 years of age, had suspected vagus nerve injury of cen- tral origin (e.g., cerebrovascular accident, neuromuscular dis- ease, brain tumor, etc.), head or neck cancer (i.e., except that isolated to the thyroid, which resulted in only surgical removal of all or part of the thyroid), and/or anterior approach cervical spine surgery. The purpose for excluding these populations was the possibility of a more complex swallowing disorder not neces- sarily limited to injury of the vagus nerve. This resulted in patients with iatrogenic and idiopathic UVFI. None of the patients had undergone a vocal fold medialization procedure prior to the videofluoroscopic swallow study. The timing between onset of UVFI and time of evaluation was not recorded. All swallow studies were preformed using a properly colli- mated OEC Medical Systems 9800 Radiographic/Fluoroscopic unit that provided a 63 kV, 1.2 mA-type output for the full field of view mode (12-inch input phosphor diameter). In accordance with our standard protocol, a metal ring of known diameter was taped to the chin or neck of the patient for measurement cali-

bration purposes. Lateral views were obtained while the patient, seated in an examination chair, was administered liquid barium (EZpaque barium sulfate suspension, 60% w/v; EZ-EM, Inc., Westbury, NY) boluses of 1 cc, 3 cc, and 20 cc and a 3-cc paste bolus (EZ-paste, EZ-EM, Inc.) measured with a syringe or graduated medicine cup. The patient was then turned to obtain anteroposterior views and administered liquid barium boluses of 3 cc and 20 cc. Studies were recorded on a Sony Md-1000 DVD recorder (Sony Corp. America, New York, NY) and were played back using Quick Time (7.7.1; Apple, Cupertino, CA). Measures were obtained from digitized images using ImageJ software (National Institutes of Health, Bethesda, MD) and software tools from Iconico, Inc (New York, NY). Specific measurement techniques have been previously described in detail. 8,9 An experienced unblinded clinician (i.e., the same clinician who conducted the videofluoroscopic swallow studies) analyzed all studies; however, because this study was retrospectively completed, there was no information available related to this study at the time of evaluation. All measures for the current study were obtained from the lateral view. The primary outcome measures were upper esophageal sphincter opening (UESmax) and the pharyngeal constriction ratio (PCR). The PCR is a validated surrogate measure of pha- ryngeal strength on fluoroscopy; and an elevated PCR suggests pharyngeal weakness. 9 The secondary outcome measures were larynx to hyoid approximation (HLx), hyoid displacement (Hmax), and total pharyngeal transit time (TPT) (see Table I for definitions). The data from each variable were compared to age and gender-matched controls with no history of dysphagia. Discrete variables were analyzed with a chi-square test of inde- pendence and an independent samples t test was used to com- pare the control and combined UVFI groups with alpha set at 0.05. A one-way analysis of variance (ANOVA) was used to com- pare the iatrogenic and idiopathic UVFI groups with the con- trol group. A Bonferroni correction was applied to adjust for multiple comparisons with alpha set at 0.01. There is a proba- bility of 0.05 that a type I error has been made in the set of tests. RESULTS A total of 137 individuals with UVFI were identified from the clinical database. There were 25 subjects who met strict inclusion and exclusion criteria (i.e., did not

Laryngoscope 124: October 2014

Domer et al.: PCR and UES Opening in UVFI

2