Dear Editor,

Progressive supranuclear palsy (PSP), also known as Steele-Richardson-Olszewski syndrome, is a rare neurodegenerative disorder. Limitations in the forward movement of the neck can make tracheal intubation and ventilation difficult to perform, resulting in life-threatening events if anesthetic protocols are not adapted.¹

Here, we report the case of an 81-year-old female with a history of PSP who was scheduled for left mammary tumor extirpation and ipsilateral lymph node excision. PSP was diagnosed in association with severe neck stiffness, bilateral lack of a downward gaze, generalized hypertonia, dysdiadochokinesia, and slight resting tremor on physical examination at the age of 65. Other medical records report untreated arterial hypertension and deficits in antithrombin III and homocysteine. The patient had not received any previous surgical interventions. The patient was classified as American Society of Anesthesiologist (ASA) status III, indicating serious limitations in cervical mobility; however, no other predictors of difficult tracheal intubation (e.g., Mallampati test equal to one, more than 3 cm mouth opening, normal ability to protrude the inferior maxillary incisor in front of the upper maxillary incisors, and normal thyromental distance) or difficultventilation were noted. General anesthesia was induced using 150 μg fentanyl and 150 mg propofol. The patient could be easily ventilated using a face mask, but after two attempts of trying to insert number 4 and 3 laryngeal mask airways (LMA, AMBU(r), Aure Once TM, USA), ventilation became inefficient though we noted improvement after cuff deflation. Tracheal intubation under direct laryngoscopy using a #7 endotracheal tube was performed without difficulty (Cormack score of 1 using a #3 Macintosh blade, Macintosh blade KAWE (r), Germany). At the end of the surgical intervention, the patient had her trachea extubated and was transferred to the postanesthesia care unit. She was returned to the ward after 4 hours without any postoperative cognitive complications, and she was discharged from the hospital on the fourth postoperative day.

PSP is usually diagnosed during the sixth or seventh decades of life and is associated with rapid progression. The average life expectancy is 10 years.² The classic risk factors include a history of cranial trauma, cerebrovascular disease, and dietary exposure to benzyltetrahydroisoquinoline (e.g., TIG: an urotensin II receptor antagonist, reticulin) and carbolines.³ The few published studies on the use of general anesthesia in these patients describe the potential difficulty of airway management due to the cervical dystonia.In the case of suspected airway stenosis, the authors recommended the use of cervical magnetic resonance imaging to assess for the presence of airway stenosis prior to intervention.1, 4 In the present case, despite the difficulty ventilating the patient using LMA, intubation was performed without incident. In addition, virtually all of patients with PSP develop frontal cognitive dysfunction, including possible dementia and subcortical distinctive manifestations (e.g., apathy, mental inflexibility, and defects in memory retrieval), all of which could predispose these patients be uncooperative and cause difficulties when attempting intubation.In contrast, there is no solid evidence in the literature that anesthetics exacerbate neurological dysfunction in these patients. In fact, our patient, who did not have advanced dementia, did not present with a worsening postoperative neurological condition.

PSP is a rare disease that causes cervical dystonia and contributes to difficulties in airway management. Could cervical dystonia be a predictor of difficult LMA insertion? Some authors have described the failure to insert an LMA in patients who had received radiotherapy to the lower part of the neck.⁵ Anatomic factors were, therefore, most likely responsible for these failures. The presence of an LMA in a narrowed hypopharynx may compress the laryngeal structures in an inextensible neck, resulting in the collapse of the glottis. Improvement in ventilation after cuff deflation in our patient lends support to this hypothesis. Panegyres et al⁶ reported that laryngeal dystonia causes upper airway obstruction in patients with progressive supranuclear palsy, but, on the other hand, the successful use of LMA in a patient with craniocervical dystonia during magnetic resonance imaging has been reported.⁷ In our opinion, specific protocols, such as the use of fiberoptic intubation or tracheostomy, should be applied in certain cases. Magnetic resonance imaging may be useful for the preanesthesia evaluation of the grade of airway stenosis.