Right upper lobe anatomy revisited: a computed tomography scan study

Abstract

Background The double lumen tube (DLT) has become the most popular way to isolate the lungs for thoracic surgery. The variable anatomy of the right main stem bronchus (RMSB) seems to be the main reason clinicians are unwilling to use the right-sided DLT (R-DLT). The factors that could compromise the adequate ventilation of the right lung are mostly the variable length of the RMSB and the misalignment of the lateral orifice of the R-DLT in regard to the right upper lobe bronchus (RULB). The objectives of this study were to validate an alternative method to estimate the RMSB length, and to determine the distribution of the angulation of the ostium of the RULB. Methods From high-resolution computed tomography scans of the thorax of 106 consecutive patients, the length of the RMSB was measured using Kim's method and the carina-to-carina method. The angle between the RULB origin and the lateral aspect of the RMSB was also measured. All these measurements were correlated and inter-observer variation documented. Results From the Kim's method, the mean (standard deviation [SD]) length of the RMSB was 25.5 (4.7) mm. From the alternative carina-to-carina method, the mean (SD) length of RMSB was 29.4 (4.6) mm. The interobserver agreement was substantial with both methods (Kim's method: intraclass correlation coefficient [ICC] = 0.84; carina-to-carina method: ICC = 0.95). Both measures were closely related (ICC = 0.93; P \ 0.001). The RULB presented a wide range angulation [mean (SD), 0.1 (9.5)°; range, -28.6 to 21.2]. Conclusion These anatomic observations provide a better understanding of the variable anatomy of the right bronchial tree and may guide thoracic anesthesiologists in the choice of the best lung isolation device for their patients.

Anatomy of the right upper lobe revisited and clinical considerations in Chinese population

“…The results of our study showed a much higher rate (52.3%) of RMSB length less than 23 mm (63.5% in women, 42.8% in men) in our patients. This percentage is comparable with that (50%) in Korea patients, and differs from that (25%) in Canadian patients [4,13]. The Kim's study had a very small number of cases, inversely, our study included the greatest number of patients (n = 2093) of all relevant studies except for our own previous study, as listed in Table 1, so the percentage is convincing.…”

“…Different mean RMSB lengths ranged from 12 to 25.5 mm had been described in previous publications [9][10][11][12][13] (Table 1). In these studies, aside from different methods, such as in vivo fiberoptic bronchoscopy, autopsy study and cast study as well as computed tomography (CT) scan, were used to measure the RMSB length, the definition of the RMSB length were ambiguous.…”

“…In these studies, aside from different methods, such as in vivo fiberoptic bronchoscopy, autopsy study and cast study as well as computed tomography (CT) scan, were used to measure the RMSB length, the definition of the RMSB length were ambiguous. In some studies, the distance between the tracheal carina and the proximal margin of the upper lobe bronchial orifice was defined as the right bronchial length (RBL) [9][10][11], however, other researchers defined the RMSB length as the distance between the tracheal carina and the distal margin of the upper lobe bronchial orifice [12,13]. Since accurate anatomy of the RMSB and RUB relates to the selecting of devices, specifically, the R-DLT for lung isolation, definite RMSB length need to be further discussed.…”

“…In recent years, CT-guided bronchial width measurement has been used to predict the appropriate DLT size increasingly, which is superior to conventional method, such as height, age, and chest X-ray [14]. A recent study involving 106 patients had provided a better understanding of the variable anatomy of the right bronchial tree by using thoracic CT imaging [13]. In 2015, our team had published a study in regard to the precise measurements of the tracheobronchial tree using CT scans in Chinese population, which focused on the entire tracheobronchial distribution, and found that there was a large individual variation in the length of the RMSB [11].…”

The combination of computed tomography measurements and flexible video bronchoscope guidance for accurate placement of the right-sided double-lumen tube: a randomized controlled trial

“…Benumof et al [34] de ned the margin of safety of Rusch RDLT intubation as the length of the RUL-VS minus RUL diameter. Kim JH et al [17,35] suggested that LDLT should be considered if the distance between the tracheal carina and the distal edge of the RUL bronchus is less than 23 mm. However, the above studies did not take into account the design and size of different brands of DLTs.…”