Spinal cord stimulator for neuropathic pain in a patient with severe disability due to transverse myelitis

Abstract

Transverse myelitis is an inflammatory disease of the central nervous system that disrupts nerve signals’ conduction. The illness is characterised by weakness in the lower limbs accompanied by paresthesia and urinary and bowel incontinence. The most disabling sequel is the onset of chronic neuropathic pain, which can severely limit the patient’s independence and negatively affect her quality of life. We present the case of a patient who received a spinal neurostimulator after a failure of conventional medical treatment. Masking pain through paresthesia, a mechanism provided by the device significantly reduces pain perception. The treatment success in our patient represents an advance in pain therapy.

Background

Transverse myelitis (TM) is an inflammatory disease of the spinal cord that affects the myelin of nerve fibres, predominantly in the cervical region (60%) and the thoracic region (33%).¹ The damage produced in the spinal cord’s ascending and descending pathways interrupts the normal conduction signals of nerves.²

The most common associated symptoms are lower limb weakness, sensory disturbances, pain and sphincter dysfunction.¹

The refractory management of pain associated with TM has a significant negative impact on the patient’s quality of life, making its treatment a real therapeutic challenge.³ For this reason, we present the case of a young patient with chronic pain refractory to conventional therapy associated with TM, who had a successful treatment after the implantation of a spinal stimulator.

Case presentation

We present a 39-year-old woman diagnosed 5 years ago with TM. The patient was initially hospitalised for lack of sensation and weakness in the lower extremities, constipation and urinary urgency.

A definitive diagnosis was established after an operation for a presumed mass at the spine’s level. A biopsy of atypical tissue was taken at the level of T10–12. The histopathological examination reported chronic inflammation. A wide laminectomy was performed with the placement of a stabiliser bar.

The patient presented a progressive motor and sensory deficit in the lower limbs accompanied by chronic pain. The pain was initially described as burning and squeezing with irradiation to the right leg.

Due to the advanced stage of the disease, a cystostomy was performed for bladder incontinence. Despite initial management with high-dose glucocorticoids, the illness progressed until she was permanently incapacitated.

Treatment

After the diagnosis of TM, the patient was initially managed by the neurosurgery service with high-dose glucocorticoids. Posteriorly, gabapentin 300 mg once a day, amitriptyline and tramadol 20 drops once a day was added. The patient also developed major depressive disorder due to chronic pain, managed by psychiatry with fluoxetine, conductive therapy and physical-occupational therapy sessions. After an overdose of tramadol that required admission to the Intensive care unit (ICU), it was decided to suspend the drug.

Several years later, she was referred to our hospital for refractory pain treatment. The patient was started on oxycodone 10 mg and gabapentin dose was increased to 300 mg every 8 hours, which produced slight improvement. Despite the opioid therapy, the pain severely limits daily activities, so a buprenorphine patch was added, and oxycodone was scaled to 40 mg. The patch was suspended due to an allergic reaction.

Despite the multidisciplinary management, the pain did not diminish, and she was unable to remain in a wheelchair for more than 2 hours. Her interpersonal and intrafamily relationships, and her personal and professional independence were severely affected due to pain. The patient reported 8–9 on the Visual Analogue Scale.

Due to the severe impact on her quality of life, it was decided to place a spinal neurostimulator. A neurostimulator with percutaneous electrodes was placed through L4 and L5 until reaching the thoracic level. During the procedure, abundant fibrosis was evident with difficult access to the thoracic spine. The electrodes were placed at the thoracic level, below the previous surgery, finding satisfactory stimulation. Electrode 1 was placed: intensity 5.5 mA, pulse duration 250 µs, frequency 80 Hz, electrode 2: intensity 6.0mA, pulse duration 350 µs, frequency 80 Hz (figure 1).

Figure 1.

Intraoperative X-ray during spinal electrode placement.

Outcome and follow-up

One week later, the patient reported a significant decrease in pain, decreasing to 2–3 on the Visual Analogue Scale, returned to her daily activities, managed to stay in a wheelchair for longer periods of time, and showed a significant improvement in the quality of sleep.

The wound healed adequately and there were no complications in the 3-month follow-up. The patient reported minor unspecified discomfort two nights before follow-up when she tried to move from the chair to the bed; for these reasons, anX-ray at the time was requested to assess possible displacement (figure 2).

Figure 2.

Radiographic control at the 3 months follow-up.

The patient described the intervention result as an improvement of more than 60% in pain. She reduced the pain medication to paracetamol on-demand, and 20% of the previously required oxycodone. The use of buprenorphine patch was discontinued.

Discussion

Our patient presented with idiopathic TM, a rare disease in clinical practice. Many factors have been associated with the disease; however, between 15% and 30% of cases are characterised as idiopathic.²

The total bilateral sensory and motor impairment was established in a period of hours, similar to other cases.² Once diagnosed, it was managed with acute phase treatment based on corticosteroids, plasmapheresis and cyclophosphamide.²

Our patient developed severe permanent dysfunction, a sequela reported in up to 44% of patients.^{2 4}

A late complication of TM is neuropathic pain below the lesion level,⁵ observed in up to 50% of cases.⁴ The pain can be explained for direct neuronal damage, orthopaedic factors or spasticity.² It is usually treated with gabapentin, carbamazepine, nortriptyline, tramadol, topical lidocaine, non-steroidal anti-inflamatory drugs (NSAIDs) and opioids.^{2 4}

Our patient did not achieve a significant remission of pain despite initial pain management; this is not uncommon due to only between 40% and 60% achieved pain relief with drug treatment.^{5 6} Spinal stimulator was considered because of the refractory pain management and significant impairment in quality of life.

Although it is recommended to place the electrodes above the lesion level, it was not possible in our case because of the severe fibrosis. However, satisfactory pain reduction was achieved.

Neurostimulation proved to be an effective treatment in patients with predominantly neuropathic pain in the lower extremities, such as those presented as sequelae of TM in our patient.^5–8

Our patient demonstrated a significant decrease in pain intensity that allowed her to return to most of her daily life activities, improved sleep quality, increased her independence and decreased the need for opioid medication.^{5 8 9} Similar cases described by Reddy et al and Leffey et al also report a significant improvement (80%) in their patient’s pain and considerable functional improvement.^{3 10}

According to a case reported by Hamid and Haider, the benefit in pain and quality of life continues at 18 months follow-up.¹¹

Despite the lack of long-term studies on the benefit of spinal neurostimulation, our case demonstrates the beneficial effect of the device in treating neuropathic pain refractory to conventional medical treatment.

Patient’s perspective.

When my illness started, my personal goals, daily activities, and my relationship with my family and friends were seriously affected. The constant presence of disabling pain diminished my desire to live. Many drugs were used by the doctors who treated me in an unsuccessful attempt to manage my pain. My life became a daily torment until they decided to try a surgery that they had never told me about. They put me on a neurostimulator, and I cannot describe the relief I felt just days after surgery. They gave me back my hope and the will to live.

Learning points.

• Pharmacological treatment could not be enough to manage chronic pain associated to Transverse Myelitis. Therefore, other treatments should be considered.

• Spinal cord stimulation effectively treats neuropathic pain associated with transverse myelitis.

• Although there is a lack of long-term studies on the final outcome, spinal cord stimulation for chronic pain should be considered an option in patients with transverse myelitis.