Association between surgical tracheostomy and chronic tracheal stenosis: A retrospective, single-center study

Abstract

Background: Tracheal stenosis is a major complication of tracheostomy. Accordingly, anesthesiologists tend to select a smaller endotracheal tube (ETT) than usual for patients with a prior tracheostomy history, regardless of the presence or absence of respiratory symptoms. However, it likely comes from our trial and error, not scientific evidence. Therefore, in this study, we retrospectively examined the association between traditional surgical tracheostomy and tracheal stenosis as assessed by transverse computed tomography (CT).

Methods: Patients who underwent surgery for head and neck cancer from January 2010 to December 2013, with a temporary tracheostomy closed within a couple of months, were included. Exclusion criteria were tracheostoma before surgery, permanent tracheostomy, or insufficient CT follow-up. Transverse CT slices were measured 2 cm above and below the tracheostomy site (0.5 cm/slice for a total of 9 slices). The minimum cross-sectional tracheal area and horizontal and vertical diameters in transverse CT slices were compared before (baseline: BL), 6 months (6M) and 12 months (12M) after tracheostomy. Tracheal stenosis was defined as a decrease in the minimum cross-sectional tracheal area compared to BL.

Results: Of 112 patients, 77 were included. The minimum tracheal area was significantly decreased at 6M and 12M compared to BL (BL: mean 285 [SD 68] mm², 6M: 267 [70] mm², P < 0.01 vs. BL, 12M: 269 [68] mm², P < 0.01 vs. BL), and the localization was predominantly at or above the tracheostomy site at 6M and 12M. Tracheal stenosis was identified in 55 patients at 6M and in 49 patients at 12M without any respiratory symptoms. With regard to horizontal and vertical diameter, only horizontal diameter was significantly decreased at 6M and 12M compared to BL (BL: 16.8 [2.4] mm, 6M: 15.4 [2.7] mm, P < 0.01 vs. BL, 12M: 15.6 [2.8] mm, P < 0.01 vs. BL).

Conclusion: Conventional surgical tracheostomy was associated with a decreased horizontal diameter of the trachea. It resulted in a decreased cross-sectional tracheal area in more than one-half of the patients; however, no patient complained of any respiratory symptoms. Therefore, even without respiratory symptoms, prior tracheostomy causes an increased risk of tracheal stenosis, and using a smaller ETT than usual could be reasonable.

Keywords: computed tomography; intubation; surgical tracheostomy; tracheal stenosis; triangulation.

FIGURE 1

Schematic of a method for measuring the tracheal lumen using computed tomography. Measurement was performed over a distance of 4 cm above and below the tracheostomy site. Each image slice was set to 0.5 cm, and 9 slices were analyzed. The minimum tracheal area among the 9 slices was selected for each time point (baseline, 6 months, and 12 months). Horizontal and vertical tracheal diameters were also measured.

FIGURE 2

Flow of study protocol. Of 112 patients who underwent surgery for neck and head cancer, 77 were included in the study. Computed tomography was performed before surgery (baseline) and at 6 and 12 months after surgery.

FIGURE 3

Tracheal stenosis after tracheostomy. The minimum tracheal area decreased significantly at 6M and 12M (both P < 0.01 vs. BL). There was no difference between 6M and 12M (P = 0.66). *P < 0.01. (B) The horizontal tracheal diameter decreased significantly at 6M and 12M compared to BL (both P < 0.01 vs. BL). There was no difference between 6M and 12M (P = 0.43). *P < 0.01. (C) The vertical diameter did not change over time (6M: P = 0.23 vs. BL; 12M: P = 0.32 vs. BL). No change was observed between 6M and 12M (P > 0.99). Bar graphs are shown as mean ± SD (A,B) and median, first, and third quartile (C). 6M: 6 months after surgery, 12M: 12 months after surgery, BL: baseline, ns, not significant.

FIGURE 4

Horizontal diameter changes in minimum tracheal area before and after tracheostomy. The distribution of horizontal diameter changes in all 77 patients was represented at 6M (A) and 12M (B) compared to BL. The most predominant range in the initial horizontal diameter was within 15 ∼ 20 mm at BL (n = 56). After tracheostomy, many of the diameters shifted shorter than the initial one. 6M: 6 months after surgery, 12M: 12 months after surgery, BL: baseline.

FIGURE 5

Localization of the site of minimum tracheal area before and after tracheostomy. (A) A total of 9 CT slices were obtained for each patient (cranial to caudal, with tracheostomy site in the middle [slice 5]). At BL, the site of minimum tracheal area was at the most cranial (slice 1) or most caudal (slice 9) slice. (B,C) At 6M and 12M, the site of minimum tracheal area was predominantly at or above the tracheostomy site. 6M: 6 months after surgery, 12M: 12 months after surgery, BL: baseline, CT: computed tomography.

FIGURE 6

Localization of the site of maximum tracheal area before and after tracheostomy. (A) A total of 9 CT slices were obtained for each patient (cranial to caudal, with tracheostomy site in the middle [slice 5]). At BL, there was no predominant localization of the site of maximum tracheal area. (B,C) At 6M and 12M, the site of maximum tracheal area was localized below the tracheostomy site (caudally). 6M: 6 months after surgery, 12M: 12 months after surgery, BL: baseline, CT: computed tomography.

FIGURE 7

Tracheal stenosis after tracheostomy. (A) Representative computed tomography image of tracheal stenosis. (B) Schematic showing triangulation after tracheostomy.