A 54-year-old woman (height 156 cm, weight 48 kg) with a 15-year history of HSP was diagnosed with lumbar spinal canal stenosis. Her chief complaint was lower back pain upon standing. Her symptoms showed progressive worsening, with severe stenosis at L4/5; consequently, decompressive laminectomy was scheduled to relieve the pain. Neurological examination revealed respective left and right straight-leg raise angles of 50° and 50°, bilateral patellar tendon reflexes were exaggerated, bilateral Achilles tendon reflexes were absent, and left and right manual muscle testing showed (5, 5; 2, 2; 3, 3; and 3, 3 [left and right, respectively]) at the tibialis anterior, lower limb extensor group, lower limb flexor, and gastrocnemius muscles, respectively. Although the patient experienced slight difficulty in standing and walking, she exhibited no dysfunction in the upper limbs; moreover, she showed no bladder or rectal disturbances. Tactile sensory function was intact. She began rehabilitation, comprising standing and walking training to achieve stable walking. She received intrathecal baclofen therapy (38 mcg/day), which relieved the symptom of spasticity.
The patient had undergone laparoscopic unilateral salpingo-oophorectomy using general anesthesia with propofol, remifentanil, and rocuronium, 2 years prior to the present operation. There were no adverse events, such as malignant hyperthermia. Preoperative examinations during the current surgery (e.g., electrocardiography, spirometry, laboratory data, and chest radiography) were unremarkable. The Mallampati classification was I, and the degree of mouth opening (i.e., initial interincisal distance) was > 35 mm. The patient had no smoking history. The patient presented to the hospital 1 day prior to surgery. She was permitted to move using a wheelchair and had no other limitations with regard to her behavior in the ward.
To measure the train-of-four (TOF), TOF-Watch (NIHON KOHDEN Corporation, Tokyo, Japan) was used as a peripheral nerve stimulator; neuromuscular activity was monitored at the adductor pollicis muscle in response to ulnar nerve stimulation. Before induction of general anesthesia, the left radial artery was catheterized for arterial line and blood gas assessment (BGA), which revealed a partial pressure of arterial carbon dioxide (PaCO2) of 36.9 mmHg and a partial pressure of arterial oxygen (PaO2) of 82.6 mmHg.
After pre-oxygenation, general anesthesia was induced using propofol (60 mg [1.2 mg/kg]) and remifentanil (0.3 mcg/kg/min) for rapid induction; rocuronium (10 mg) was then infused. When the TOF ratio decreased and TOF counts reached 4 (2 min after initial rocuronium infusion), additional rocuronium (10 mg) was added (a total of 20 mg rocuronium was administered). TOF counts reached 0 after additional rocuronium administration. Tracheal tube intubation was performed easily using a videolaryngoscope (Airway Scope, AWS-S100, HOYA, Tokyo, Japan). Anesthesia was maintained using desflurane (end-tidal concentration 4.0–4.2%) in oxygen and air (fraction of inspired oxygen 0.4) and remifentanil (0.1–0.4 mcg/kg/min). Fentanyl (50 mcg/dose or 100 mcg/dose) was infused (total of 250 mcg, i.e., 5 mcg/kg was administered). Rocuronium (10 mg) was infused (0.2 mg/kg) when TOF count reached 1. The total dosage of rocuronium was 40 mg in 2.5 h. Vital signs and bispectral index (approximately 40) were stable intraoperatively. In total, 1.4 L of crystalloid was infused intraoperatively. Sufficient akinesia was achieved, and surgery was completed safely.
Neuromuscular blockade was reversed using sugammadex 100 mg (2 mg/kg); postoperative TOF counts were 4. A TOF ratio > 0.9 was obtained. The patient uneventfully emerged from anesthesia. She was rapidly able to follow instructions and breathe spontaneously while intubated and demonstrated adequate tidal volumes before extubation.
After extubation, oxygen saturation remained > 99% when supplying oxygen at 3 L/min. Her respiratory rate was 16 breaths/min and PaCO2 and PaO2 were 46.4 mmHg and 150 mmHg, respectively. Other parameters were approximately identical to their preoperative measurements. The patient’s respiratory condition was stable, without signs of neurological deterioration.
The patient postoperatively used NSAIDs when she experienced wound pain or headache without opioids. One week postoperatively, the patient exhibited fever, which led to a diagnosis of wound infection. She underwent curettage, and the wound was washed and drained. Antibiotics were used to enable her to recover from the wound infection. The patient was recommended bed rest postoperatively; she was permitted to reposition to Fowler’s position if there was no pain. On postoperative day 12, the drain tube was removed, and she was allowed to move using a wheelchair. The patient restarted rehabilitation on postoperative day 18. She trained by standing and walking and gradually recovered to her preoperative level of mobility. She was finally discharged home on postoperative day 43.