To the Editor:—
A 62-yr-old man who had undergone surgical removal of a T9–T10 neurofibroma a decade previously was referred to the Magnetic Resonance Imaging Institute of our institution for a semi-urgent examination to rule out recurrence of the disease, precipitated by the recent onset of severe back pain. He had severe spastic paraparesis with marked involuntary movements, even when supine. However, despite sedation with midazolam, intravenous propofol, and (subsequently) inhaled nitrous oxide and isoflurane (up to 2% inspired), immobility could not be achieved. The examination was therefore canceled to allow further discussions with the treating physicians.
Given the risk of a worsening neurologic deficit if a lesion were undiagnosed and hence left untreated, it was determined that obtaining a high-quality scan was mandatory. General endotracheal anesthesia with neuromuscular blockade was considered, but given the patient's obesity and smoking history, alternatives were also discussed. A spinal anesthetic was considered and discussed with the patient's neurosurgeon, who was agreeable to this plan as long as the lumbar puncture could be performed below the level of the patient's suspected thoracic lesion. A 22-gauge Quincke spinal needle was inserted in the L3–L4 interspace, with the patient lying on his left side (an atraumatic bloodless tap). Plain bupivacaine was progressively and slowly injected (5 mg and then 2.5 mg; total, 7.5 mg) to achieve a level of T12. The patient stopped moving his legs, and the magnetic resonance imaging examination was easily completed. The patient was stable during the scan and recovered motor function uneventfully 20–30 min after completion of the scan. No complications were noted, and he was sent home 1 h later.
To our knowledge, a spinal anesthesia for a magnetic resonance imaging examination has not been reported previously. This approach may be reasonable in patients with involuntary movements of the legs in whom difficulties in performing a general anesthetic are anticipated.