Intrathecal injection of alcohol or phenol has been an effective pain management technique for patients who live with chronic pain. The injection damages the pain pathways, providing pain relief for up to several months. Although injection into the subarachnoid space can provide pain relief in up to 60 percent of patients, epidural injection is often preferred because of the side effects associated with subarachnoid injections. Side effects are usually sudden and are rarely delayed.
The authors of this article present the case study of a previously healthy 36-year-old woman who injured her thumb and arm in a fall, subsequently developing reflex sympathetic dystrophy. Following unsuccessful conservative treatment, as well as spinal and stellate ganglion blocks (injections into the sympathetic nerve tissue), the patient underwent an epidural injection in her upper thoracic region, the upper part of her mid-back, just below the neck area. She immediately developed a weakness in the left arm and leg and then went into respiratory arrest.
Following a 3-month period of intense rehabilitation, the patient was able to walk short distances with a cane although she still experienced some weakness in both legs. Two months later, she was readmitted to the hospital with increasing weakness and numbness of both legs, malnutrition, and pressure sores.
Assessment through magnetic resonance imaging (MRI) showed that the patient had increased spinal fluid pressure from T2 to T8 (vertebrae in the spine, labeled as T1 being the top thoracic vertebra and T12 is the lowest one) and a myelomalacia (softening of the spinal cord). Her doctors diagnosed myelopathy due to an arachnoid cyst. Following surgery to remove the cyst and to stabilize her cerebral spinal fluid pressure, the patient remained severely disabled.
The authors of this article note that complications of the injection are well known and include meningitis, as well as the spread of the agent into neighboring structures, including the spinal cord. However, arachnoid lesions of the spine was not a known complication. These lesions usually occur as the result of trauma, hemorrhage, parasitic infections, or other causes of inflammation. There are no standard treatment options. The usual options do include removing the lesion, draining the fluid, or providing a shunt for the fluid.