Spinal anesthetic management for discectomy in a patient with amyotrophic lateral sclerosis -A case report-
A 64-year-old man, 165 cm in height and 70 kg in weight, visited the department of neurosurgery due to severe pain on the left lateral leg. On physical examination, left ankle dorsiflextion was impaired. Magnetic resonance imaging (MRI) of lumbosacral vertebral column showed a left paramedian disc extrusion, between lumbar 4 and 5 vertebras. The patient was scheduled for discectomy. In premedical history, the patient complained of dysarthria, dysphagia and weakness in both legs, while walking 3 years ago. He also complained of dyspnea, although, there were no abnormalities on the blood gas analysis. On the physical findings by a neurologist, deep tendon reflex was exacerbated and babinski test was positive. The electromyogram (EMG) suggested that the patient had a motor neuron disease and he was diagnosed with ALS. Pulmoary function test was not performed before the operation, due to the undergoing emergency operation for resolution of severe pain on the left leg.\nSpinal anesthesia for discectomy was chosen to avoid respiratory complication, which is associated with general anesthesia. No preanesthetic medication was given. Spinal anesthesia was done between lumbar 3 and 4, via a midline approach in the left lateral position and was injected with 10 mg of 0.5% hyperbaric bupivacaine, plus fentanyl 20 µg using a 25 guage Quinke spinal needle. Immediately after the injection of local anesthetic agent and opioid, the patient was placed back to the supine position. The level of the spinal anesthesia was T10, after 15 minutes and then we changed the patient's position from supine to prone position. Propofol at a rate of 0.5-1.0 mg/kg/hr was infused for sedation with O2 5 L/min via nasal cannula. Intraoperatively, vital signs were as follows: blood pressure of 122 to 139/81 to 95 mmHg; heart rate between 75 and 97 beats/min; and oxygen saturation of 100%. There were no complications for one and a half hour of the surgery. The patient was monitored for one hour, in postoperative anesthetic care units (PACU), and then was discharged from PACU. The patient was fully recovered at 5 hours, after the spinal anesthesia and no exacerbation of neurologic signs or symptoms were revealed. The patient was discharged two days after surgery and at the 3 months follow-up, there were no neurologic complications due to spinal anesthesia.