Lumbar sympathetic blocks and chemical sympathectomies are used for the pain treatment
of peripheral arterial occlusive disease or sympathetically maintained pain syndrome after
nerve injury or complex regional pain syndrome (CRPS). A 30-year-old patient was referred
to the pain department with all the clinical signs and symptoms of a CRPS of the right
foot one and a half years after being surgically treated for rupture of the achilles tendon.
An inpatient admission was necessary due to insufficient pain reduction upon the current
treatment, strong allodynia in the medial distal right lower leg and decreased load-bearing
capacity of the right foot. A computed tomography (CT)-guided lumbar sympathetic block
at the right L3 (Bupivacaine 0.5%, 4 mL) led to a skin temperature increase from 21°C before
block to > 34°C for about 5 hours after the intervention. The patient experienced significant
pain relief, indicating sympathetically maintained pain. Thus, we performed a CT-guided
lumbar sympathetic neurolysis at the same level (ethanol 96%, 2 mL) 5 days later, achieving
again a significant skin temperature increase of the right foot and a slight reduction of his
pain intensity from numeric rating scale (NRS) 7 prior to the intervention to NRS 4 after 8
hours (NRS, 0 = no pain, 10 = strongest pain imaginable). Eight months later a repeated
inpatient admission was necessary due to considerable pain relapse and decreased loadbearing capacity of his right foot. A CT-guided lumbar sympathetic neurolysis was repeated
at the L4 level on the right side and was successful, inducing a significant skin temperature
increase. Despite a temporary irritation of the genitofemoral nerve 8 hours after the
intervention, a delayed irritation of the lateral femoral cutaneous nerve occurred. This was
a long-lasting lesion of the lateral femoral cutaneous nerve following a CT-guided chemical
sympathectomy with a low-volume ethanol 96% application - a complication which has not
been described in literature until now. This is probably caused by broad dissemination of
the neurolytic agent along the psoas muscle despite a correct needle position and spread of
contrast agent. The development of this nerve injury even after injection of a small volume
of ethanol (2 mL) may be delayed.
Key words: Complex regional pain syndrome, CRPS; sympathetically maintained
pain syndrome, sympathectomy, neurolysis, lateral femoral cutaneous nerve, ethanol,
complication, genitofemoral nerve
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