Case Study – Persistent pain after surgery
Mrs K is a 48 year old lady who was referred with radicular leg pain that persisted despite an otherwise complicated spinal operation.
Her symptoms first started whilst lifting heavy boxes at home. She has a sudden onset of low back and radicular pain down her right leg (sciatica). When symptoms didn’t settle with conservative management and a transforaminal steroid injection she was referred to a spinal surgeon. She was found to have L5 foraminal stenosis compressing the nerve. She underwent an uncomplicated L5/S1 laminectomy. Despite initially reporting a significant reduction in her pain, gradually the pain returned and was impacting on her function and quality of life.
She was investigated with another MRI that showed no residual nerve root compression. She was advised by her surgeon that further surgery was unlikely to help.
After a medication and physiotherapy trial, it was decided to trial a spinal cord stimulator. This is the insertion of a small lead that can stimulate the dorsal columns of the spinal cord and modulate the pain signal. It is often effective in neuropathic pain such as what Mrs K was experiencing.
A trial of spinal cord stimulation therapy was performed. This is a day surgical procedure performed under sedation. The small leads are advanced through a needle into the epidural space. The lead is sercured to the skin and connected to a battery controller. Over the next 7 days Mrs K’s pain and activity was recorded. She found that the therapy reduced her pain considerably and allowed her to be more active with less medication. The temporary leads were then removed and she was booked to undergo permanent implant of the spinal cord stimulation system.
The spinal cord stimulation system was implanted under sedation, and she was discharged home the following day. The pain relief obtained from the spinal cord stimulator allowed Mrs K to reduce her analgesic medication and engage in active physiotherapy.
Case Study – Lumbar Facet Joint Pain
JG is a 60 year old office worker who has suffered with increasing left sided low back pain. His pain is described as a dull ache that is exacerbated by prolonged standing and walking. His pain radiates down the lateral thigh, but not beyond the knee. He has previously managed well with NSAIDs and intermittent physiotherapy. In recent years, his pain-related limitation of function has progressively increased.
JG’s posture and gait were normal, but he demonstrated pain and stiffness when rising from the chair. He had a good range of lumbar flexion without pain. Lumbar extension and rotation to the left was quite uncomfortable.
There was minor midline spinal tenderness and he was most tender to the left of the L4 spinous process. Neurological examination of the lower limbs revealed no motor or sensory changes.
A CT scan of his lumbar spine showed mild disc dessication at L4/5 level, with facet joint arthritis at L4/5 and L5/S1. A SPECT scan shows uptake in the left L4/5 facet joint.
He was reviewed by a spinal surgeon who ordered a left L4/5 facet joint injection. This gave significant but short-lived relief, lasting unfortunately only one day. He was told that spinal surgery was unlikely to alleviate his pain.
JG’s clinical symptoms and radiological findings are consistent with facet joint pain. A diagnostic medial branch block to the left L4/5 facet joint was performed. This involves the injection of 0.5mL of 0.5% bupivacaine to the medial branch nerve above and below the affected joint, anaesthetising the joint for 4 to 8 hours. During this time, JG’s pain diary indicated a significant reduction in his lumbar spinal pain. His symptoms returned to baseline the day after the injection.
Following this positive response to a diagnostic medial branch block, JG underwent radiofrequency denervation to the medical branch nerves supplying the L4/5 facet joint. This involves thermal disruption to the medial branch nerve using a specialised needle. This procedure was performed with radiological guidance under light sedation.
After three days of post-procedure discomfort his symptoms began to subside and at a follow up in 4 weeks he reported an 80% reduction on his pain NRS (Numerical Rating Scale).
After 18 months his symptoms slowly returned. This procedure was repeated and the same pain reduction was observed.
Facet Joint Arthropathy
Facet joint arthropathy is a significant cause of lower back pain, particularly in the older population. The facet joints are identified as the origin or “pain generator” of low back pain in 15 to 45% of cases, with a higher incidence in the older age group. These small joints at the back of the spine provide stability and flexibility to the spine and can become inflamed with age, wear and tear or with injury.
The pain that results from facet joint arthropathy is typically deep and aching, made worse by activity and can be felt on one or both sides of the lumbar spine. Typically, the pattern of referred pain associated with the facet joints is into the buttocks, groin or down the legs to the knees.
The changes of facet joint arthropathy can be seen on CT scan, MRI and bone scan, but as these radiological findings can be present in asymptomatic patients, diagnostic blocks are the only definitive test for the condition.
Identifying the facet joints as the “pain generator” in back pain can be done using a series of diagnostic local anaesthetic techniques (see medial branch blocks). Once the diagnosis is established, a more permanent treatment to block pain signals from the inflamed joint can be undertaken. See Radiofrequency Facet Joint Denervation for more information.