Foot drop following spinal anaesthesia

Dear Editor,

We report a case of foot drop following spinal anaesthesia. The incidence of nerve injury related to spinal anaesthesia is less than 1:10,000, and most incidences have unknown aetiology.1 ^and 2 However, if patients complain of pain or paraesthesia during spinal anaesthesia they must be watched for any unwanted neurological deficits. We report a case involving a possible needle trauma or local anaesthetic drug-related neural structure injury and subsequent foot drop.

A healthy 31-year-old adult female was scheduled for anal fissurectomy surgery. She had no medical comorbidity. Complete blood count and coagulation parameters were normal. After obtaining informed written consent and after overnight fasting, she was prepared for the operation. Routine monitorization (non-invasive blood pressure, electrocardiography, and pulse-oximeter) was performed in the operating room.

Once all aseptic precautions had been completed, a 27 g Quincke needle was inserted in the L4-L5 interspace. As the needle entered the subarachnoid space, the patient exhibited a jerky reaction that was followed by paraesthesia and pain. The needle was immediately withdrawn slightly and once the pain had subsided spinal anaesthesia was achieved with 10 mg (2 mL) 0.5% bupivacaine (heavy marcaine^(r), AstraZeneca, Istanbul, Turkey) In order to achieve saddle block, the patient was kept in a sitting position for five minutes and was turned to a prone position to operation.

In terms of perioperative sedation, midazolam (3 mg) was given intravenously. The operation lasted for 30 minutes. The patient was lightly sedated and was comfortable during the procedure.

At the postoperative sixth hour, the patient noticed that she was unable to move her left foot. After light touch neurological examination, pin prick and vibration senses were all reported to be absent. All reflexes were brisk except for the left knee, the ankle and the plantar reflexes, which were absent. There was also a persistent foot drop involving with left foot plantar flexion (0/5), although the right foot was normal. Because the MRI was normal, surgical intervention was not scheduled. Methylprednisolone (250 mg) and vitamin B complex treatment (Bemiks^(r), Zentiva, Istanbul, Turkey) were started.2 ^and 3 Dexamethazone (16 mg) and B complex therapy were continued for five days. Physiotherapy was scheduled, and the patient was discharged. After 3 months of physiotherapy, the patient's symptoms were markedly improved.

Following spinal anaesthesia, mechanical trauma resulting from a needle or accidentally unsuitable drug placement are the most probable causes of neurological complications. As in many of the reported cases,1 2 ^and 3 we could not explain the exact aetiological factor that led to the neurological complications, which included paraesthesia and pain.

Orientation of the needle is also an important factor in terms of the depth and extent of nerve injury. A transverse needle insertion is associated with greater nerve injury, while a horizontal insertion is less dangerous. During the spinal anaesthesia procedure, paraesthesia associated with needle movement may cause nerve damage. The intensity of the paraesthesia is a strong indicator of nerve damage. The weakness and sensorial defects may be long lasting.4

We recommend a brief neurological examination of the lower limbs before a spinal anaesthesia protocol and, in an acute developed spinal anaesthesia-related foot drop situation, an urgent diagnose is needed and a treatment procedure is crucial for improved long term outcomes.

References

• 1. Nirmala BC, Gowri Kumari. Foot drop after spinal anaesthesia: a rare complication. Indian J Anaesth. 2011;55:78-9.
• 2. Ghai A, Hooda S, Kumar P, Kumar R, Bansal P. Bilateral foot drop following lower limb orthopedic surgery under spinal anesthesia. Can J Anesth. 2005;52:550.
• 3. Reynolds F. Damage to the conus medullaris following spinal anaesthesia. Anaesthesia. 2001;56:238-47.
• 4. Auroy Y, Narchi P, Messiah A, Litt L, Rouvier B, Samii K. Seri- ous complications related to regional anaesthesia: results of a prospective survey in France. Anaesthesiology. 1997;87:479-86.

Publication Dates

• Publication in this collection
  Sep-Oct 2015