Introduction

According to the 2022 American Society of Anesthesiologists Practice Guidelines [1], difficult airway management refers to situations in which an anesthesiologist encounters difficulty or failure in maintaining the airway—whether anticipated or not—during procedures such as face mask ventilation, laryngoscopy, ventilation with a supraglottic airway, tracheal intubation, extubation, or invasive airway management [1].

Tracheobronchopathia osteochondroplastica (TO) is a relatively benign condition of the tracheobronchial tree, characterized by the proliferation and accumulation of diffuse cartilaginous and osseous nodules that protrude into the walls of the trachea and bronchi [2]. This condition often presents with nonspecific symptoms or may be asymptomatic.

In both cases presented, the condition was identified prior to surgery. In the first case, tracheal intubation was successfully achieved by replacing the endotracheal tube (ETT) with a smaller 6.5 mm tube. In the second case, however, tracheal intubation was challenging despite the use of bronchofibroscopy (BFS) and the use of a smaller-diameter ETT. On the fifth attempt, the ETT cuff was positioned just beyond the vocal cords, enabling adequate ventilation and oxygenation to be maintained throughout the robotic-assisted radical prostatectomy (RARP). This case report highlights the specific challenges of airway management in patients with TO undergoing robotic and laparoscopic surgery.

Cases

Ethical statements: This study was approved by the Institutional Review Board (IRB) of Korea Institute of Radiological & Medical Sciences (IRB No. 2025-03-006). The IRB approved a waiver of informed consent.

1. Case 1

A 78-year-old male patient (159.2 cm, 57 kg) was scheduled for RARP owing to a malignant neoplasm of the prostate. One year prior to surgery, a chest computed tomography (CT) scan performed during a health check-up revealed nodular thickening of the tracheal wall. He was subsequently referred to our hospital's pulmonology department, where BFS and biopsy confirmed a diagnosis of TO (Fig. 1). The patient was placed under observation. BFS revealed cartilaginous nodules extending from the proximal trachea to the carina, with smaller nodules observed distally in both the right and left main bronchi, though the overall nodule count was low. Preoperative laboratory results, medical history, and pulmonary function tests (FEV₁ [forced expiratory volume in 1 second], 2.24 L; FVC [forced vital capacity], 3.0 L; FEV₁/FVC, 74%) were unremarkable. No significant issues were noted during the preoperative evaluation. On the day of surgery, the patient received 0.2 mg of glycopyrrolate via intramuscular injection as premedication before being brought to the operating room. Preoxygenation was performed using a high-flow nasal cannula (FiO₂ [fraction of inspired oxygen], 1.0; flow, 30 L/min) for 5 minutes, followed by bag-mask ventilation (FiO₂, 1; flow, 6 L/min). General anesthesia was induced with lidocaine 60 mg, propofol 100 mg, and rocuronium 60 mg. Bag-mask ventilation was maintained, and sevoflurane was initiated at 6%. When the Train-of-Four (TOF) count reached 0, tracheal intubation was attempted with a 7.0 mm ETT, but the procedure was challenging. A second attempt with a smaller 6.5 mm ETT was successful and without complications. Anesthesia was maintained with sevoflurane at 1.5%, and the fresh gas flow was set at 3 L/min (FiO₂, 0.5 in air). Arterial and central venous lines were placed. Continuous infusions of remifentanil (effect-site concentration [Ce], 1.5 ng/mL; Minto model) and rocuronium (infusion flow rate: 3 μg/kg/min) were administered using the Agilia SP TIVA system at the start of surgery. Ventilation and oxygenation were monitored using end-tidal CO₂ (EtCO₂) and peripheral oxygen saturation (SpO₂). Tidal volume was adjusted from 7 mL/kg to 8 mL/kg to maintain peak inspiratory pressure (PIP) below 25 cmH₂O and EtCO₂ below 35 mmHg, even during surgical insufflation. The respiratory rate was adjusted from 10 to 12 breaths per minute. SpO₂ remained consistently at 100%. The patient remained hemodynamically stable, with no intraoperative complications. During emergence, sugammadex 200 mg, esmolol 20 mg, nicardipine 0.5 mg, and dexamethasone 10 mg were administered. Once the TOF ratio exceeded 0.9, extubation was performed without complications.

2. Case 2

A 71-year-old male patient (172 cm, 66.1 kg) was scheduled for RARP owing to malignant neoplasm of the prostate. Nine years prior to surgery, chest CT during a health check-up revealed suspicious findings suggestive of a laryngeal tumor. However, the patient was unable to follow up owing to personal reasons. One year later, he presented with worsening evening cough and was referred to the pulmonology department, where he underwent BFS, biopsy, and imaging studies including chest CT (Fig. 2). BFS revealed nodular mucosal elevations along the entire length of the trachea, primarily affecting the posterior wall (Fig. 3). These elevations narrowed the airway lumen and extended from the carina to the proximal portions of both main bronchi. The patient was subsequently diagnosed with TO and has been under observation since. Preoperative laboratory and pulmonary function tests (FEV₁, 3.01 L; FVC, 4.05 L; FEV₁/FVC, 74%) showed no abnormalities. The patient had a history of hypertension and was found to have a right bundle branch block on electrocardiogram but reported no cardiac symptoms. No other significant findings were noted during the preoperative evaluation. On the day of surgery, the patient received premedication with 0.2 mg glycopyrrolate via intramuscular injection before being brought to the operating room. Preoxygenation was performed using a face mask for 5 minutes (FiO₂, 1; flow, 6 L/min), followed by bag-mask ventilation. General anesthesia was induced with lidocaine 60 mg, propofol 120 mg, and rocuronium 50 mg for muscle relaxation. Once the TOF count reached 0, intubation was attempted using a video laryngoscope with a 7.0 mm ETT; however, the tube could not be advanced. The tube size was then changed to a 6.5 mm ETT for a second attempt. Although the vocal cords were clearly visualized, the ETT could not be advanced beyond them. Subsequently, BFS was performed by inserting the bronchoscope through the tube to guide it to the appropriate depth. During the procedure, if SpO₂ levels dropped, mask ventilation was applied before resuming intubation. Following five intubation attempts under BFS guidance using gentle rotation over a 25-minute period, intubation was confirmed via video laryngoscopy, which demonstrated that the ETT had been advanced 8 cm beyond the vocal cords (Fig. 4). When we checked ETT cuff had barely passed the vocal cords, the cuff was inflated and the tube was secured in place. Adequate ventilation (EtCO₂ <35 mmHg) and oxygenation (SpO₂ 100%) were confirmed. Dexamethasone 5 mg was administered, and arterial and central venous lines were placed. Continuous infusions of remifentanil (Ce, 1.5–2 ng/mL; Minto model) and rocuronium (infusion flow rate, 4 μg/kg/min) were administered using the Agilia SP TIVA system at the start of surgery. During surgical site insufflation, volume control ventilation was used, with tidal volume adjusted from 7 to 8 mL/kg to maintain PIP below 25 cmH₂O. Respiratory rate was adjusted from 11 to 13 breaths per minute, maintaining EtCO₂ below 35 mmHg. Arterial blood gas analysis during insufflation revealed PaCO₂ of 39.5 mmHg (EtCO₂, 35 mmHg) and PaO₂ of 218 mmHg. The patient remained hemodynamically stable, and no complications occurred throughout the procedure. During emergence, sugammadex 200 mg was administered. Extubation was performed without complications once the TOF ratio exceeded 0.9.

Discussion

Wilks first reported a case of this condition in 1857, and Aschoff introduced the term “tracheobronchopathia osteochondroplastica” in 1910. Jackson later published the first case report of TO in an American journal in 1932 [3]. TO is a benign disorder of the tracheobronchial tree, characterized by multiple submucosal nodules (0.1–1.0 cm in size) composed of cartilage and bone, typically protruding into the anterolateral walls of the trachea and bronchi [4].

Clinically, TO is often asymptomatic and incidentally discovered. However, it can present with wheezing, cough, hemoptysis, dyspnea, and, rarely, obstructive symptoms. As a result, it is frequently identified via fiberoptic bronchoscopy or chest CT performed for unrelated reasons [2,5].

In anesthesiology, TO is significant because it may result in unexpected difficulty in airway management and intubation, even when preoperative evaluations and clinical symptoms do not suggest a difficult airway. Warner et al. [6] reported an incidental finding of TO during attempted tracheal intubation. Despite switching to a smaller 7.0 mm ETT on the third attempt, intubation remained unsuccessful. Consequently, the anesthesia team decided to awaken the patient and perform further evaluation to elucidate the underlying cause of the subglottic obstruction. Subsequent diagnostic workup, including bronchoscopy and imaging, led to the final diagnosis of TO. In contrast, Takamori et al. [7] reported successful intubation by switching to a 6.5mm ETT with gentle rotation in patient with TO who underwent robot-assisted total prostatectomy. Morax et al. [8] reported a significant cuff leak following intubation with a 7.0 mm ETT under BFS guidance during laparoscopic cholecystectomy, so they attempted cuff overinflation to maintain adequate ventilation despite of the risk of tracheal wall injury.

In other reports, Eckhardt et al. [9] described using a laryngeal mask airway (LMA) as an air leak blocker after placing a 7.0 mm ETT during tracheoplasty in a patient with TO. Ishii et al. [10] reported the use of an LMA under intermittent positive pressure ventilation with a nasogastric tube during laparoscopic hepatectomy under general anesthesia in a patient with TO.

In robotic surgeries such as RARP, the steep Trendelenburg position induces several physiological changes, including increased preload, reduced functional residual capacity and vital capacity, as well as elevated peak and plateau airway pressures. Moreover, pneumoperitoneum may lead to hypercarbia, which may result in pulmonary vasoconstriction, ventilation-perfusion mismatch, hypoxemia, respiratory acidosis, decreased myocardial contractility, arrhythmias, and cerebrovascular vasodilation—potentially increasing intracranial pressure. Effective ventilation is therefore essential in such procedures.

Although our cases were limited to RARP, the anesthetic considerations discussed are broadly applicable to other forms of laparoscopic or robot-assisted abdominal surgeries. These procedures similarly involve pneumoperitoneum and steep Trendelenburg positioning, both of which are known to substantially elevate airway pressures and decrease pulmonary compliance. In patients with TO, whose airways are already compromised by submucosal nodular formations, these physiological changes may further impair adequate ventilation and oxygenation.

The use of a smaller-diameter ETT should be considered in patients with TO when attempting intubation. In some cases, including one of the two cases presented in this report, successful intubation and adequate ventilation were achieved simply by switching to a smaller-sized tube. However, there are patients—including the second case in this report and several previously documented cases—for whom appropriate airway management could not be achieved despite the use of a smaller-diameter tube. Notably, Ishii et al. [10] reported the successful use of an LMA in a patient with TO undergoing laparoscopic hepatectomy; however, such an approach may not be universally applicable in cases where elevated airway pressures or aspiration risk are anticipated, because LMAs have lower seal pressures than ETTs, making them less suitable when higher airway pressures are required. In robotic surgeries requiring steep Trendelenburg positioning, the presence of TO in conjunction with compromised respiratory mechanics necessitates meticulous preoperative airway planning. This highlights the importance of individualized airway strategies beyond merely downsizing the ETT size.

According to 2022 American Society of Anesthesiologists difficult airway algorithm, no more than three to four tracheal intubation attempts are recommended in adult patients [1]. If these attempts are unsuccessful, alternative airway strategies such as the use of a supraglottic airway device or face mask ventilation may be considered. However, in robotic surgeries, the use of LMAs is often limited due to the steep Trendelenburg position and pneumoperitoneum. Although invasive techniques such as surgical cricothyrotomy remain an option, they are associated with significant patient discomfort and potential complications. In our case, a fifth attempt at endotracheal intubation was undertaken with bronchoscopic guidance using gentle rotation. During this attempt, the position of the cuff relative to the vocal cords was carefully evaluated. Following intubation, adequate ventilation was confirmed using arterial blood gas analysis and capnography.

In conclusion, airway management in patients with TO requires more than simply selecting a smaller ETT. Early recognition, preoperative planning, and the use of BFS guidance and individualized airway management strategies are essential to ensure successful intubation and adequate ventilation, particularly in laparoscopic or robot-assisted surgeries.

Article information

Conflicts of interest

No potential conflict of interest relevant to this article was reported.

Acknowledgments

We thank the Medical Scientist Research Support Program at the Medical Science Substantiation Center, Korea Institute of Radiological & Medical Sciences, for providing English editing services (No. 50543-2025).

Funding

None.

Author contributions

Conceptualization: SJA. Formal analysis: JYL. Supervision: JYL. Writing-original draft: SJA. Writing-review & editing: JYL. All authors read and approved the final manuscript.

Fig. 1.

Bronchoscopic evaluation of a patient (Case 1) showing a large lesion characteristic of tracheobronchopathia osteochondroplastica arising from the distal tracheal wall, along with diffuse nodularity throughout the tracheobronchial lumen.

Fig. 2.

Chest computed tomography image of Case 2 showing multiple small calcifications throughout the trachea, sparing the posterior membrane, suggestive of tracheobronchopathia osteochondroplastica.

Fig. 3.

Bronchoscopic evaluation of a patient (Case 2) demonstrating diffuse nodularity characteristic of tracheobronchopathia osteochondroplastica throughout the tracheobronchial lumen. (A) Trachea. (B) Trachea, carina, left main bronchus, and right main bronchus.

Fig. 4.

Video laryngoscopic views of Case 2 showing that the endotracheal tube had been advanced 8 cm beyond the vocal cords. (A) The intubated state at induction. (B) The intubated state just before emergence.

References

• 1. Apfelbaum JL, Hagberg CA, Connis RT, Abdelmalak BB, Agarkar M, Dutton RP, et al. 2022 American Society of Anesthesiologists practice guidelines for management of the difficult airway. Anesthesiology 2022;136:31–81.ArticlePubMedPDF
• 2. Luo T, Zhou H, Meng J. Clinical characteristics of tracheobronchopathia osteochondroplastica. Respir Care 2019;64:196–200.ArticlePubMed
• 3. Secrest PG, Kendig TA, Beland AJ. Tracheobronchopathia osteochondroplastica. Am J Med 1964;36:815–8.ArticlePubMed
• 4. Raess PW, Cowan SW, Haas AR, Zhang PJ, Litzky LA, Miller WT, et al. Tracheobronchopathia osteochondroplastica presenting as a single dominant tracheal mass. Ann Diagn Pathol 2011;15:431–5.ArticlePubMed
• 5. Abu-Hijleh M, Lee D, Braman SS. Tracheobronchopathia osteochondroplastica: a rare large airway disorder. Lung 2008;186:353–9.ArticlePubMedPDF
• 6. Warner MA, Chestnut DH, Thompson G, Bottcher M, Tobert D, Nofftz M, et al. Tracheobronchopathia osteochondroplastica and difficult intubation: case report and perioperative recommendations for anesthesiologists. J Clin Anesth 2013;25:659–61.ArticlePubMed
• 7. Takamori R, Shirozu K, Hamachi R, Abe K, Nakayama S, Yamaura K, et al. Intubation technique in a patient with tracheobronchopathia osteochondroplastica. Am J Case Rep 2021;22:e928743.ArticlePubMedPMC
• 8. Morax LS, Breitenmoser I, Konrad CJ. Tracheobronchopathia osteochondroplastica: a rare cause of tracheal tube cuff leak. Anaesth Rep 2023;11:e12240.ArticlePubMedPMC
• 9. Eckhardt WF, Forman S, Denman W, Grillo HC, Muehrcke D. Another use for the laryngeal mask airway: as a blocker during tracheoplasty. Anesth Analg 1995;80:622–4.ArticlePubMed
• 10. Ishii H, Fujihara H, Ataka T, Baba H, Yamakura T, Tobita T, et al. Successful use of laryngeal mask airway for a patient with tracheal stenosis with tracheobronchopathia osteochondroplastica. Anesth Analg 2002;95:781–2.ArticlePubMed

Figure & Data

References

Citations

Citations to this article as recorded by