HSC Section 6 Nov2016 Green Book

Kraft et al

Table 1.  Clinical Presentation.

below the true vocal folds and measuring 12 mm long. Fifteen patients had preoperative computed tomography (CT) scans. The median degree of stenosis as determined by CTwas 56.8% (Cotton-Myer grade 2). Four patients had grade 1 stenosis at presentation and 4 patients had grade 3 stenosis. Median follow-up after surgery was 21.4 months (IQR, 5.1-43.1). For the 11 patients receiving at least 2 dilations, the median time between the first and second procedures was 23.7 months. Three patients ultimately proceeded to definitive cricotracheal resection. Seventeen of the 25 patients had a preoperative PFT in addi- tion to at least 1 postoperative PFT performed within 8 weeks of surgery. Four parameters demonstrated a statisti- cally significant improvement after intervention: (1) PEF (absolute change = 2.54 L/s), (2) PIF (absolute change = 1.57 L/s), (3) FEV1/PEF (absolute change = 0.44), and (4) FIF50% (absolute change = 1.71 L/s). FEV1, FVC, FEF25%-75%, and PEF/PIF did not change significantly (Table 2). Preoperative and postoperative PFT values were then examined in the context of balloon size. Improvement in the PIF was the only parameter that was affected by the size of dilation, with rank-order testing indicating a greater degree of improvement with use of a larger balloon ( P = .047) (Table 3). Changes in PFT Over Time Seven patients of the 25 in this sample had at least 3 PFTs taken following the initial dilation. PEF, PIF, FEV1/PEF, and FIF50% from these samples were plotted as a function of time. There is a linear relationship between time and both PEF and FEV1/PEF ( P = .0307 and P < .001, respectively). The slope of the line was unique to each patient (Figures 1 and 2). PIF and FIF50% generally decrease as the time from surgery increases, but a linear relationship could not be established (data not shown). Five of the 7 patients did have a second procedure but had not accumulated a sufficient number of subsequent PFTs during the study period for analysis. (The patients represented by a star and hexagon had only 1 procedure.) Discussion Not all patients are ideal candidates for endoscopic man- agement of subglottic stenosis. Historically, previous failed dilations, stenosis length greater than 1 cm, circumferential stenosis, evidence of cartilage loss/damage, a history of severe bacterial infection with tracheotomy, posterior glot- tic stenosis with arytenoid fixation, and involvement of the inferior margin of the vocal folds were considered poor Preoperative Versus Postoperative PFT Assessment

Median

Interquartile Range

Race  Caucasian

23  2

 Latina

Age at surgery, mo

45.3

38.5-67.0 61.5-85.5 1.55-1.65 23.5-32.1 38.9-78.4 11.0-16.5 9.0-17.0 5.1-43.1 1-3

Weight, kg Height, m

70

1.6

Body mass index, kg/m 2

28.7

Stenosis, %

58.60

Cotton-Myer grade

 2

Distance below cords, mm 15

Length of stenosis, mm

12

Follow-up, mo

21.4

No. of procedures

 2

1-3

Time between first & second surgeries, mo

23.7

15.6-31.8

to identify patients with a preoperative diagnosis of sub- glottic stenosis. Clinical records were then further screened to select patients who met the inclusion criteria. All data points, to include demographic, clinical, operative, labora- tory, radiographic, and pulmonary functional data, were entered in a Microsoft Excel spreadsheet. Data were imported into and analyzed via SPSS version 20.0 (SPSS Inc, Chicago, Illinois, USA). A P value < .05 was consid- ered to be significant. As we could not assume a normal distribution for our small sample size, a Wilcoxon signed rank test was used to look for differences in the pre-dilation and post-dilation differences in pulmonary function data. Subsequently, a Kruskal-Wallis test was performed on those PFT parameters that improved sig- nificantly to determine the contribution of dilation size on the change. For those measures that changed significantly, post- operative PFT values were plotted as a function of time to assess the rate of change after intervention. Results Clinical Presentation and Evaluation of Stenosis A total of 25 new patients with iSGS were seen between 2006 and 2011 at our clinic. As anticipated, all patients were female. Ninety-two percent (N = 23) were white and 8% (n = 2) Hispanic. The median age at the time of the first surgical intervention was 45.3 years (interquartile range [IQR], 38.5-67.0), with a median body mass index of 28.7 kg/m 2 (IQR, 23.5-32.1) (Table 1). A total of 45 procedures were performed. Twelve patients had 1 procedure, 9 patients had 2 procedures, 2 patients had 3 procedures, 1 patient had 4 procedures, and 1 patient had a total of 7 procedures (median = 2).At the time of initial presen- tation, the typical stenosis was described as beginning 15 mm

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