Unilateral blindness following superior laryngeal nerve block for awake tracheal intubation in a case of posterior cervical spine surgery

Abstract

Background: Superior laryngeal nerve block (SUPLANEB) is a popular airway anesthesia technique utilized for successful awake endotracheal intubation in patients with significant cervical spine instability. If not performed by an expert, it carries the risk of general/neurologic complications that are typically minimal/transient. However, permanent blindness and/or upper cranial nerve neuropathies may occur. Here, we describe a case in which a young patient underwent an atlantoaxial fusion for a C2 nonunion (e.g., following a fracture) complicated by unilateral blindness due to a SUPLANEB. Case Description: A 25-year-old neurologically intact male underwent a C1-C2 posterior arthrodesis to address a nonunion of a C2 fracture. To perform the awake nasotracheal intubation, a SUPLANEB was performed using a video laryngoscope. Although the operation was uneventful, postoperatively, the patient reported left visual loss accompanied by left-sided facial numbness and hearing loss. On examination of the left eye, the anterior segment and fundus examinations were normal, but the OCT (optical coherence tomography) and retinal angiography demonstrated left-sided postischemic retinal edema with permeability of the intraocular vessels. Although the cranio-orbital computed tomography scan showed only mild pneumocephalus, the CT angiogram scan revealed abnormal air in the left carotid sheath accompanied by diffuse subcutaneous emphysema. Further, brain and orbital magnetic resonance imaging scans were normal. The patient was treated with pure oxygen, systemic steroid therapy, and nimodipine. The pneumocephalus and subcutaneous emphysema resolved on day 3. At 2 months follow-up, the patient remained blind on the left side, but had no further neurological deficits. Conclusion: Blindness and upper cranial nerves neuropathies should be considered as potential complications of SUPLANEB. Notably, these deficits were not directly related to the operative positioning or neurosurgical spinal procedure.

Ultrasound-Guided Block of the Internal Branch of the Superior Laryngeal Nerve Reduces Postoperative Sore Throat Caused by Suspension Laryngoscopic Surgery: A Prospective Randomized Trial

“…However, SLNB, by using a local anesthetic as an injection, might cause complications, such as intravascular Abbreviations: BIS, Bispectral index; Ce, Concentration effect-site; HR, Heart rate; iSLNB, Internal branch of superior laryngeal nerve block; MAP, Mean arterial pressure; POST, Postoperative sore throat; SLN, Superior laryngeal nerve; SLNB, Superior laryngeal nerve block. injection, nerve damage (12), and dysphagia, and even more serious complications including blindness or upper cranial nerve neuropathies (13).…”

“…Meanwhile, SLNB or block or transection of its internal branch is a viable therapeutic option for medically refractory neuropathic cough ( 8 , 11 ). However, SLNB, by using a local anesthetic as an injection, might cause complications, such as intravascular injection, nerve damage ( 12 ), and dysphagia, and even more serious complications including blindness or upper cranial nerve neuropathies ( 13 ).…”

“…Superior laryngeal nerve block is now commonly used in endotracheal intubation and bronchoscopic maneuvers, which result in relatively transient stimulations, so SLNB performed by lidocaine injection is the first choice in these clinical applications ( 13 , 15 ). These are obviously different from patients with laryngeal cancer undergoing suspension laryngoscopic surgery, whose operative process has a longer duration and causes stronger stimulation.…”

Anesthetic management of airway stent placement by rigid bronchoscopy with superior laryngeal nerve block while preserving spontaneous breathing: A case report

“…By placing a linear ultrasound probe in the parasagittal plane under the jaw, the greater horn of the hyoid bone, thyroid cartilage, thyrohyoid membrane, and thyrohyoid muscle can be identified, and the internal branch of the superior laryngeal nerve is detected between the hyoid bone and thyroid cartilage 12,18–20 . Reported complications of SLNB that was performed blindly include unilateral visual impairment with left facial numbness and hearing loss 21 . Therefore, SLNB performed under real‐time ultrasound guidance is preferable.…”

“…12,[18][19][20] Reported complications of SLNB that was performed blindly include unilateral visual impairment with left facial numbness and hearing loss. 21 Therefore, SLNB performed under real-time ultrasound guidance is preferable.…”