This is a 53-year-old woman with a history of migraines. She presented with sciatica refractory to treatment and a herniated disc L5-S1.
After informed consent and preoperative study without contraindications, L5-S1 microdiscectomy was performed.
The operative technique, including preparation and positioning, was as follows:
- Anaesthesia
General anaesthesia was performed, with orotracheal intubation. Induction was performed with Propofol, analgesia with Renifentanil (m opioid receptor agonist, with analgesic potency similar to fentanyl), and relaxation with Atracurium Besylate (competitive or non-depolarising neuromuscular blocking agent). Sevofluorane was used as a volatile anaesthetic. During the procedure, 100 mg Tramadol (centrally acting analgesic, pure non-selective µ, delta and kappa opioid receptor agonist) and 25 mg Dexketoprofen tromethamol were administered. The duration of anaesthesia was 1 hour 50 minutes without any complications of any kind during the anaesthesia.
- Placement
The patient was placed in the Mohammedan position, with the pectoral region and iliac crests supported on special pillows, with central recesses to avoid decubitus of the abdomen and breasts.
The head was supported on a cushioned system in the form of a cranially open donut. To avoid ocular support, the eyes were protected with lubricant and eye pads held in place by a bandage placed circularly over the head at the level of both eyes.
The lower extremities were padded in the decubitus regions (both knees). Pedial and posterior tibial pulses were checked on both sides. The position of the patient's back was parallel to the ground.
- Surgical technique
It was performed by conventional microsurgery with a two-finger midline incision, section of the common sacro-lumbar aponeurosis, retraction of the paravertebral musculature, flavectomy, root dissection and excision of the extracted disc herniation. Blood loss was minimal and no blood was administered. A small amount of hydrogen peroxide was used as a haemostatic (about 5 cc).
- Immediate postoperative period
Upon awakening from anaesthesia, the patient reported that she could not see anything at all in either eye. Ophthalmology was requested and no pathology was found. Ocular tension was normal. The photomotor and consensual reflexes were preserved.
An emergency brain CT scan was performed, which showed an image in the right intraventricular choroidal circulation compatible with a gas bubble. Another right occipital occipital juxta-osseous image was considered doubtful.
A cranial MRI was performed, which showed a diffuse signal increase in T2 sequences in posterior areas of both occipital lobes. The MRI angiography was normal.
The picture was interpreted as being of vascular origin, either positional or derived from the patient's migraine history, and she was empirically treated with dexamethasone and vasodilators.
After 6 hours, she reported perceiving indistinguishable and faint chromatic shapes, with the appearance of a threat reflex.
The following morning (12 hours after the operation), he reported having recovered his vision, although he perceived chromatic halos around the figures presented to him. These dyschromatopsias disappeared within 24 hours. A follow-up MRI showed significant improvement of the occipital images seen on the previous MRI.
Subsequent controls (one month after surgery) showed visual normality.
