This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Schoenhage, K. O. Articles by Koenig, H. M. Search for Related Content PubMed PubMed Citation Articles by Schoenhage, K. O. Articles by Koenig, H. M. Related Collections Airway Anesthetic Techniques

---

GENERAL ARTICLES

Unanticipated Difficult Endotracheal Intubations in Patients with Cervical Spine Instrumentation

Kai O. Schoenhage, MD^*, and Heidi M. Koenig, MD

*Department of Anesthesiology, University of Illinois at Chicago; and Department of Anesthesiology and Perioperative Medicine, University of Louisville, Kentucky

Address correspondence and reprint requests to Heidi M. Koenig, MD, Department of Anesthesiology and Perioperative Medicine, University of Louisville, 530 South Jackson St., Room C2A03, Louisville, KY 40202. Address e-mail to heidi.koenig{at}louisville.edu.

	Abstract

Top Abstract Introduction Case Reports Discussion References

 
We present two cases of unanticipated difficult airway in patients requiring reoperation after cervical spine instrumentation. In both cases, the upper airway examination was normal, and fiberoptic-guided intubation proceeded with the patient sedated and breathing spontaneously. Cord visualization was difficult, but the scope was eventually advanced into the trachea and the endotracheal tube placed safely. Later review of radiographs showed the previously unrecognized protrusion of cervical hardware into the meso- and hypopharynx. We recommend that anesthesiologists review recent radiographic studies for potential airway compromise before approaching the airway of patients presenting for revision of cervical instrumentation.

	Introduction

Top Abstract Introduction Case Reports Discussion References

 
More patients are undergoing cervical spine hardware instrumentations; rarely, such patients require reoperation. The Mallampati airway assessment in these patients may be difficult and falsely reassuring. Immobilization of the unstable cervical spine may render a full airway examination difficult or impossible.

We describe two patients who underwent reoperation for hardware revision. We proceeded with awake, fiberoptic-guided oral intubation to preserve spontaneous respiration and allow for documentation of the neurological examination after intubation. Prevertebral protrusion of cervical hardware into the pharynx made orientation and access to the glottis unexpectedly difficult.

	Case Reports

Top Abstract Introduction Case Reports Discussion References

 
Case 1
A 64-year-old man with severe rheumatoid arthritis, resulting in cervical deformity and subluxation, presented for revision of unstable posterior cervical instrumentation. He had undergone anterior corpectomy and posterior cervical fusion 1 yr earlier. The cervical pathology had led to generalized muscular weakness with some respiratory impairment and cachexia. No signs of upper airway obstruction, such as dysphonia or stridor, were present. He had a gastric tube in place for dysphagia.

We undertook awake fiberoptic-facilitated endotracheal intubation after he was sedated with careful titration of midazolam (2 mg), propofol (300 mg), and remifentanil (75 µg). Supplemental oxygen was delivered by nasal cannula, and the pharynx was topically anesthetized with lidocaine gel and benzocaine/tetracaine spray. Arterial saturations remained more than 97% throughout the intubation process.

While introducing the fiberscope in the midline, we noted a bulge of the retropharyngeal mucosa resembling a "second uvula" and protruding far into the pharynx just below the level of the epiglottis. There were only two narrow canals bilaterally that barely communicated anteriorly. After several attempts, the tip of the fiberscope was successfully passed around the obstacle, and further landmarks were not recognized until the arytenoids suddenly became visible. The scope was advanced, the 7.0 ID endotracheal tube (Mallinkrodt, Hazelwood, Missouri) was threaded without difficulty, and the airway was secured. The patient experienced no respiratory, cardiovascular, or neurological distress or damage during the prolonged management of the situation.

After the start of surgery, computed tomography scans (Fig. 1) became available that showed a dislodged anterior cervical screw protruding into the submucosa of the meso- and hypopharynx causing the unanticipated obstruction.

View larger version (157K): [in this window] [in a new window]   Figure 1. Case 1. (A) The lateral scout of the computed tomography scan of the head and neck area demonstrates the protruding anterior plate just opposite the epiglottis (white arrows) and the posterior wiring eroding into the foramen magnum (black arrow). Compare to D. (B) The computed tomography at the level of the epiglottis (white arrow) demonstrates the hardware (black arrow) protruding into the airway. (C) The fiberoptic view near the same height as shown in B. Anterior or at the top of the image is the base of the tongue (white triangle), in the middle is the tip of the epiglottis (black arrow), and posterior is the hardware protruding beneath the edematous pharyngeal mucosa (white arrow). (D) Lateral view soon after the previous two surgeries, 11 months before this case, with initial position of anterior and posterior hardware.

Postoperatively, after revision of the posterior instrumentation, the trachea remained intubated. Two days later, because the patient remained very weak, an elective tracheostomy was performed to avoid further airway and respiratory complications. He was discharged to a nursing home and subsequently developed a wound infection and died.

Case 2
A 68-year-old woman with cervical radiculopathy, diabetes mellitus, hypertension, and a large sellar mass presented for cervical exploration 8 days after anterior cervical discectomy and fusion (C3-6). On postoperative Day 7, she had experienced a fall that dislodged the screws anteriorly. This was diagnosed by conventional radiograph. She demonstrated increased right arm weakness and reported dysphagia since the fall.

After the patient was sedated (titrated midazolam 4 mg, propofol 200 mg, and remifentanil 225 µg) and topical anesthesia (Cetacaine spray) was applied, as in Case 1, we started awake oral fiberoptic intubation because of the possibility of cervical instability. The tip of the epiglottis was visualized. Below that, the retropharyngeal space was only a side-to-side slit-like opening, with a tiny dark opening in the midline beyond it. We advanced the scope blindly until the tracheal rings became visible, and again the intubation (7.0 ID endotracheal tube) proceeded without difficulty. The neurological examination was unchanged compared with the preoperative examination, and the patient was anesthetized. On review, the radiographs (Fig. 2) clearly demonstrated a hematoma and submucosal air, as well as the broken screws and the plate anteriorly dislodged into the airway. Postoperatively, her trachea was extubated, and she immediately demonstrated improved strength in her upper extremities.

View larger version (94K): [in this window] [in a new window]   Figure 2. (A) Lateral cervical spine radiograph demonstrating the approximately 1-cm anteriorly dislodged inferior part of the plate (black arrow) after the patient’s fall (compare with B). Anterior to the plate is submucosal emphysema. The airway is limited to a slit (white arrow) at the level of the hyoid bone. (B) Radiograph before the patient’s fall with the plate still in proper position.

	Discussion

Top Abstract Introduction Case Reports Discussion References

 
These case studies demonstrate that unrecognized retropharyngeal protrusion of dislodged cervical hardware can partially obstruct the upper airway. Sedating such a patient and approaching the obstructed airway from above can rapidly become a dangerous "cannot ventilate, cannot intubate" situation. In Case 1, a tracheostomy would have been the appropriate first choice for the airway because he was quite weak and had a compromised airway. In Case 2, the team should have been ready to perform a tracheostomy urgently. Several reports describe acute and subacute airway obstruction from hematomas, tumors, surgical trauma, and edema or abscesses. The potential of these conditions to cause difficulty with glottic access and intubation are well appreciated by anesthesiologists (1–3). Slowly developing processes (4) are equally challenging in managing the airway. However, cervical hardware issues may not raise the same degree of suspicion, particularly because such patients are less likely to report shortness of air and have been recently tracheally intubated.

As illustrated by the presented cases studies, in patients with previous surgery of the cervical spine, anesthesiologists should review the most recent radiographic studies for evidence of potential airway compromise by the hardware and, if possible, obtain three-dimensional computed tomography images to visualize the airway before entering it physically (5–7). Valuable information that cannot be obtained through physical examination, such as position of hardware relative to the airway, airway diameter, and patency, become visible on these images. Although the surgeons involved would have studied the films, they are usually focused on the boney spine and the hardware relative to it, rather than the airway.

Based on the relationship of the airway to the hardware and other anatomical changes since a previous normal tracheal intubation, a plan to control the airway should be prepared. It is unrealistic to attempt intubation from above when there clearly is not enough room for an endotracheal tube to pass. The intubation options are limited in cases where the spine must remain immobilized and, if the radiographs show a fixed obstruction, as in Case 1, the anesthesiologist should proceed immediately to a surgical airway (8). Other techniques might be used to push glossal or pharyngeal tissue aside to obtain control of the airway despite any retropharyngeal bulging without requiring excessive neck movements. However, they could move the screw into a position that completely obstructs the airway. Spontaneous ventilation should be maintained while the airway is secured with fiberoptic guidance or surgically. Finally, the neurological examination should be documented before general anesthesia is induced.

	Footnotes

 
Accepted for publication September 19, 2005.

	References

Top Abstract Introduction Case Reports Discussion References

 

1. Mazzon D, Zanatta P, Curtolo S, et al Upper airway obstruction by retropharyngeal hematoma after cervical spine trauma: report of a case treated with percutaneous dilational tracheostomy. J Neurosurg Anesthesiol 1998;10:237–40.[Web of Science][Medline]
2. Pollard BA, El-Beheiry H. Pott’s disease with unstable cervical spine, retropharyngeal cold abscess and progressive airway obstruction. Can J Anaesth 1999;46:772–5.[Web of Science][Medline]
3. Harrop JS, Vacarro A, Przybylski GJ. Acute respiratory compromise associated with flexed cervical traction after C2 fractures. Spine 2001;26:E50–4.[Medline]
4. Hassard AD. Cervical ankylosing hyperostosis and airway obstruction. Laryngoscope 1984;94:966–8.[Web of Science][Medline]
5. Naguib M. The three-dimensional computed tomography imaging and prediction of unanticipated difficult tracheal intubation. Anesth Analg 2001;92:281–2.[Free Full Text]
6. McGuire G, El-Beheiry H. Complete upper airway obstruction during awake fibreoptic intubation in patients with unstable cervical spine fractures. Can J Anaesth 1999;46:176–8.[Web of Science][Medline]
7. Kanaya N, Kawana S, Watanabe H, et al The utility of three-dimensional computed tomography in unanticipated difficult endotracheal intubation. Anesth Analg 2000;91:752–4.[Abstract/Free Full Text]
8. Caplan RA, Benumof JL, Berry FA, et al Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2003;98:1269–77.[Web of Science][Medline]

This article has been cited by other articles:

				J. M. Walz, M. Zayaruzny, and S. O. Heard Airway Management in Critical Illness Chest, February 1, 2007; 131(2): 608 - 620. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Schoenhage, K. O. Articles by Koenig, H. M. Search for Related Content PubMed PubMed Citation Articles by Schoenhage, K. O. Articles by Koenig, H. M. Related Collections Airway Anesthetic Techniques