Post-procedure adhesive arachnoiditis following obstetric spinal anaesthesia.

Sir,

Adhesive arachnoiditis is a crippling disorder in which the pia-arachnoid undergoes extensive inflammatory reactions to injurious stimulus, resulting in subarachnoid scarring. A Swedish study reports the incidence of neurological complications as one case per 2834 subarachnoid blocks and at least one permanent damage for every 923 epidural blocks.[1] A Finnish study reports an incidence of serious complications as 0.45/10,000 for intrathecal and 0.52/10,000 for epidural blocks.[2]

A 35-year-old mother with no significant medical history, in her second pregnancy, underwent spinal anaesthesia for an elective caesarean section at 40 weeks gestation at another hospital. As per the information obtained, spinal anaesthesia in sitting position was performed with due aseptic precautions in L2-L3 interspace using 10% povidone-iodine (betadine™) solution. The cerebrospinal fluid (CSF) tap could be obtained on the second attempt. After aspiration of clear, free-flowing CSF, 12 mg of 0.5% hyperbaric bupivacaine was administered. Surgery proceeded uneventfully.

On the second post-operative day, on the removal of the urinary catheter, the patient complained of urinary incontinence with the loss of sensation over the perineal area and buttocks. Gradually she also complained of constipation, following which an enema was given on the fourth post-operative day. She passed stool but, subsequently, lost her bowel control too.

The patient was referred 11 days post-partum to our centre with signs of S2-S4 radiculopathy, urinary retention, constipation with faecal impaction, loss of sensation over buttocks and perineal area with weak perianal reflex. All her records from the previous hospital were obtained. A thorough examination demonstrated localised unilateral right-sided sensory loss over T11-T12 dermatome. The rectum was hugely loaded with faecal matter. A lumbosacral spine magnetic resonance imaging (MRI) [Figure 1] showed thickening, clumping and nodular enhancement of cauda equina nerve roots, suggestive of arachnoiditis. CSF analysis showed mild lymphocytosis.

Figure 1

Axial magnetic resonance imaging of lumbosacral spine T2 weighted, the arrow showing thickening, clumping and nodular enhancement of cauda equina nerve roots-suggestive of arachnoiditis (likely post-surgery/procedure)

A neurosurgical opinion was taken and the patient was put on a short course of steroids (tablet deflazacort six mg thrice daily). She was asked to undergo physiotherapy and was also suggested transcutaneous electrical nerve stimulation therapy.

The patient was discharged to a rehabilitation centre where she received oral methylprednisolone 16 mg once daily for 7 weeks with gabapentin 100 mg thrice daily for 3 weeks. A repeat MRI 2 months later showed mild enhancement of cauda, clumping of root and resolution compared to the previous MRI. The patient was advised pelvic floor exercises with dietary adjustments to control the faecal incontinence. Steroids were tapered over 2 months after reviewing her 30 days later. She was advised to remove catheter under medical guidance and watch for retention and bladder sensation.

At 12 months follow-up, the patient has significantly regained her bladder control. There was still considerable impairment in bowel control. The anal tone had not completely resolved till the date of submission of this manuscript.

Contamination of intrathecal local anaesthetic drugs with noxious chemicals has been widely suggested as an aetiology in cases of adhesive arachnoiditis; phenolic, acidic and detergent contaminants all being known neurotoxic agents.[34] Alcoholic chlorhexidine, in 2008, was the identified as a culprit in a case of arachnoiditis in a trial held at the United Kingdom.[5]

We considered povidone-iodine contamination as a possibility in this case, by contamination of the injectate or improper cleaning of povidone iodine from the skin before proceeding with the subarachnoid block.

Without more definitive data, neuraxial blocks should be done under stringent aseptic, atraumatic techniques after discarding all sources of contamination. It also seems pertinent to explain to patients the risks of late, permanent neurological deficit while obtaining informed consent.

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Conflicts of interest

There are no conflicts of interest.