Perioperative airway assessment is particularly important in patients with congenital anomalies that may cause obstruction. Although collagenopathies are reportedly associated with impaired musculoskeletal development such as kyphoscoliosis, tracheomalacia, midface hypoplasia, and cleft palate , which are likely to induce difficult airway management, rapid development of airway edema during airway management has rarely been described. We previously reported the development of airway constriction after several trials of tracheal intubation in the present patient associated at the age of 6 years . At that time, it was not clear whether the laryngeal and epiglottic edema was due to soft tissue vulnerability caused by the collagenopathy or by the repeated trials of tracheal intubation, which can develop independent of Kniest dysplasia.
We experienced failure of tracheal intubation and glottis edema again after only two trials of tracheal intubation when this patient was 13 years of age. The Japanese Society for Anesthesiologists (JSA) airway management guideline recommends preoperative airway evaluation by a modified Kheterpal’s model to predict combined difficult facemask ventilation and direct laryngoscopy . In our patient, none of the 12 assessment factors of this model were found, and facemask ventilation and direct laryngoscopy were easily performed. However, endoscopic examination revealed that the larynx was small. These episodes suggest that immature development of the airway can be preoperatively diagnosed even at a higher age and that perioperative rapid development of airway edema should be expected regardless of age in patients with Kniest dysplasia. Airway management with tracheal intubation rather than a laryngeal mask was chosen at the age of 13 years because preoperative evaluation by physical examination did not indicate airway constriction. However, a supraglottic airway device should have been used without attempting tracheal intubation regardless of the patient’s age because of the soft tissue vulnerability caused by the collagenopathy. In addition, the 2014 JSA airway management guideline 2014 states that the capnogram waveform provides only limited information in the neonatal and pediatric population and that the ventilation status grades in these groups of patients should therefore be determined together with any other clinical information available. Although the capnogram wave form was maintained at a plateau without exhibiting an obstructive pattern or increase in peak airway pressure, the possible development of airway edema should be considered in patients with a collagenopathy.
Segawa et al. . reported a case involving a patient with Kniest dysplasia in which increased difficulty in performing tracheal intubation occurred as the patient aged. Although tracheal intubation was easily performed at the age of 6 years, only the tip of the epiglottis was observed with the laryngoscope, and the trachea was blindly intubated at the age of 11 years. This implies that anatomical changes of the larynx with growth may cause difficult airway management in patients with Kniest dysplasia. Whether mucosal irritation by repeated tracheal intubation at a younger age led to the laryngeal thickening and airway narrowing is unclear, but the small larynx noted by the otolaryngologist suggests that impaired laryngeal growth was present in this patient. The edema around the vocal cords persisted for 9 days, and the tracheal tube was extubated on postoperative day 21 at the age of 6 years. The prolonged contact of the tracheal tube with the mucosa at the level of the glottis may have exacerbated the edematous changes that were induced by tracheal intubation. Therefore, even if organic constriction is not detected by preoperative evaluation, tracheal intubation should be avoided as much as possible.
Patients with Kniest dysplasia often require several operations because of multiple osteochondral tissue anomalies. Type II collagen also plays a role in the early stage of wound healing after surgery. However, Husain et al. . reported a case in which a patient with Kniest dysplasia underwent multiple procedures in the head and neck region, including cochlear implantation, mandibular distraction, palatoplasty, and laryngotracheal reconstruction without any associated complications with respect to wound healing such as soft tissue dehiscence, hypertrophic scar formation, or relapse up to 36 months of age.
Although whether collagenopathy can influence the healing of airway edema or subsequent narrowing of the glottis due to persistent hypertrophy remains unclear, airway assessments are required during the perioperative period, even after growth.
In summary, we have herein presented a patient with Kniest dysplasia in whom trials of tracheal intubation induced laryngeal edema both at the age of 6 years and again at 13 years. Patients with Kniest dysplasia can develop airway narrowing that is not detectable by preoperative interviews or physical examination. Therefore, preoperative assessment of the laryngopharynx and trachea by endoscopy and computed tomography is required to exclude anomalies such as tracheomalacia and airway narrowing. Additionally, because of connective tissue vulnerability, tracheal intubation may also exacerbate airway edema even if the laryngeal condition is normal preoperatively. Therefore, alternative airway management methods such as the use of a laryngeal mask should be considered.