Abstract

This is the case report on a 1-year 9-month-old boy suffering from spondyloepiphyseal dysplasia congenita who was successfully intubated with our modified lightwand intubation procedure for general anesthesia to undergo bilateral herniorrhaphy despite the great likelihood of facing a difficult airway because of unstable cervical spine. We bent the pediatric wand after it was encased in an endotracheal (ET) tube of appropriate diameter. The light tip of the wand was let to protrude just out of the bevel of the ET tube. Once the light bulb properly transilluminated the trachea, the ET tube was threaded gently into the trachea. The patient recovered from anesthesia smoothly and was discharged on the next day. This maneuver can facilitate both visual and tactile confirmations of the position and proper tube size. The effectiveness and safety of our modified lightwand intubation procedure is well demonstrated.

Keywords

cervical vertebrae; intratracheal; intubation;

1. Introduction

Spondyloepiphyseal dysplasia congenita (SDC) is a rare autosomal dominant genetic disorder of dwarfism involving the vertebral column and epiphyses of long bones. Because these patients have short necks with limited flexion and odontoid hypoplasia with atlantoaxial instability,¹ airway management is challenging. Although fiberoptic intubation remains the gold standard for pediatric difficult airway management, there are few reports recommending that lightwand intubation is also a good alternative.² To date, however, there is no report on the use of lightwand to manage difficult airway in a pediatric patient with dwarfism and unstable cervical spine. We share our experience in successful intubation in a child with SDC with our newly developed modified lightwand intubation procedure.

2. Case report

A 1-year 9-month-old boy with SDC was scheduled for bilateral herniorrhaphy. He stood only 78 cm (3–10 percentile) and weighed 11.2 kg (10–25 percentile). Physical examination revealed hypertelorism, low hairline, short neck, and thoracic kyphoscoliosis. Bony crepitus with neck movement was also noted. Radiographic examination revealed scoliosis of thoracolumbar spine with decreased vertebral body height. Poor ossification of odontoid process and atlantoaxial subluxation were also noted (Fig. 1).

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Fig. 1. Cervical spine X-ray, lateral view. Left film shows decreased vertebral body height and short neck. Right film shows atlantoaxial subluxation (arrow).

General anesthesia was induced with 55 mg of thiopental. After demonstrating that the lungs could be easily ventilated by bag and mask without neck extension or flexion, 25 mg of succinylcholine was given to facilitate endotracheal (ET) intubation. A specially designed pediatric lightwand (Trachlight; Laerdal Medical Corporation, Wappingers Falls, NY, USA) encased in a lubricated uncuffed ET tube (Kendall, ID: 5.0 mm) with the lighting tip protruding just beyond the bevel of the ET tube was inserted (Fig. 2). After the location of the light bulb was confirmed in the trachea, the ET tube was threaded gently into the trachea. During the whole intubation process, there was no neck movement. Intraoperative course was uneventful, and the patient was extubated while he was still deeply anesthetized and he recovered from anesthesia smoothly. He was discharged on the next day.

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Fig. 2. Photograph of modified lightwand endotracheal (ET) tube assembly. The pediatric wand (Trachlight) was bent to around 80° “hockey-stick” formation. The bend was made at approximately the base of the tongue along the patient’s profile, such that the stylet tip was at the level of the laryngeal inlet when the proximal portion was situated in the oropharynx. An uncuffed tracheal tube (of diameter selected on the basis of the patient’s age) was then mounted on the pediatric lightwand with the tip of the light stylet protruding beyond the ET tube. The wand light tip was left naked by placing the ET tube just below the bending site (arrow).

3. Discussion

Lightwand intubation technique needs less manipulation of C-spine movement in sharp contrast to direct laryngoscopy³ and has been used successfully in adult patients with cervical spine injury.⁴ Although lightwand intubation procedure is considered a safe and effective alternative way for tracheal intubation in pediatric patients,⁵ there is limited information to date about managing unstable cervical spine in infants or children with the lightwand intubation technique. In enclosing the light stylet in the ET, it is suggested that the tip of the stylet is anchored just inside the tracheal tube.⁶ Usually, in the adult patients, the glottic opening is much bigger than the outer diameter of the ET tube used. In pediatric patients, the reasons for the failure of lightwand intubation (inappropriately large ET tube, truly difficult tracheal entry, or other technical problems) are difficult to differentiate.⁷ To remedy these ambiguous drawbacks in lightwand intubation usage in complicated situations, we modify the lightwand intubation procedure. We bend the pediatric light wand, which is enclosed in the lubricated ET approximately to 80° in “hockey-stick” formation. The bend takes approximately at the base of the tongue along the patient’s profile such that the stylet tip is at the level of the laryngeal inlet when the proximal portion is situated in the oropharynx.⁸ The lighting tip of the wand is left to protrude the ET tube just below the bending site. The assembled lightwand is inserted so that the naked tip of the light stylet is made to enter the trachea first and then the ET tube is gently threaded into the trachea. Entry into the glottic opening in pediatric patients is much easier using a naked wand tip alone than a conventional tube wand assembly. Once the light stylet transilluminates the trachea at proper position, we have overcome the difficulty of trachea entry. Failed intubation because of an oversized ET tube can be easily detected by the unusual resistance encountered when threading the ET tube. This maneuver can also reduce trauma to the glottic structure caused by repeated trials. Our modified lightwand intubation procedure can give both visual and tactile confirmation of the proper tube size and position.

In clinical studies, there is no evidence of burn injuries caused by conventional use of Trachlight. As for our modification, the risk of tracheal mucosal burn caused by modified lightwand intubation procedure could be very low. The reasons are as follows. Modified lightwand intubation can mostly be completed in less than 30 seconds, following the first blink of Trachlight. Animal study has also demonstrated that the trachea mucosa is not injured even by a 250-second focused Trachlight tip exposure.⁹ In clinical practice, the tip of the lightwand is on moving rather than fixed stationarily at a single location on the tracheal mucosa. Further investigation about safety and efficacy will be done in the near future.

There are few previous reports on the anesthetic management of SDC.10, 11, 12 Although successful tracheal intubation by direct laryngosopy has been reported,¹² Redl¹³ reported the case of a young patient with SDC in whom massive pyramidal tract signs developed after direct laryngoscopic tracheal intubation, resulting in mortality. In our case, the anticipated difficult airway and possibly unstable cervical spine was successfully managed by using modified lightwand intubation without neck movement.

In surgically treated children with dwarfism and unstable cervical spine, the objective of airway management is to prevent neck movement. The safest way to approach this objective, as considered, is to have the patient intubated fiberotically under deep general anesthesia facilitated by maintaining ventilation and anesthesia first with a nasopharyngeal airway. However, fiberoptic intubation requires expensive equipment and a high level of skill.

In conclusion, we successfully intubated a child with SDC with difficult airway and unstable cervical spine by a modified lightwand intubation procedure. When managing pediatric patients with possibly unstable cervical spine, such as trauma victims, rheumatoid arthritis, Down’s syndrome, and so on, the use of modified lightwand intubation should be considered as a safer intubation alternative than direct laryngoscopy.

^† There is no conflict of interest.

^‡ Support was provided solely from institutional and/or departmental sources.