How an almond-sized implant - which takes just 20 minutes to insert - could ease lower back pain with donor cells

An implant the size of an almond is being used to treat chronic lower back pain.

The device, which takes just 20 minutes to insert near the base of the spine, is packed with donated bone cells.

These gradually seep out over weeks and months to form healthy, strong bone that stabilises the sacroiliac joints — among the largest joints in the body, linking the pelvis to the spine. Their job is to provide stability and act as shock absorbers for the back and pelvis.

But almost one in three cases of chronic lower back pain in the UK is due to excess movement — or destabilisation — in these joints. This is usually the result of inflammation arising from injury, or wear and tear from the joint disease osteoarthritis. 

With the new implant, healthy bone cells ‘fuse’ with the damaged joint, creating strong new bone that restores stability and soothes pain. 

The new implant allows healthy bone cells to ‘fuse’ with the two sacroiliac joints that link the pelvis to the spine, creating strong new bone that restores stability and soothes pain

The sacroiliac joints connect the hip bones to the sacrum at the bottom of the spine.

Reinforced with strong ligaments, these joints bear the load of the upper body when you stand, sit, walk or jump and also help with forward and backward bending.

If one or both of the joints become hypermobile (where the degree of movement is greater than it should be) or hypomobile (when there is too little movement), this can lead to chronic pain.

Hypermobility causes inflammation that affects the joint and surrounding nerves, while in hypomobility — often caused by osteoarthritis — the bones in the hip and sacrum rub against one another, triggering pain.

Current treatments include steroid injections (to dampen inflammation), physiotherapy and painkillers. 

In severe cases, surgeons fuse the joints together (the sacrum and the hip) with metal implants to restrict excess movement. But it can be several weeks before patients can even stand up properly after the operation.

The new implant, called the LinQ Fusion System and tested at Rush University in Chicago in the U.S., could be a simpler and effective alternative.

Doctors apply a local anaesthetic to the lower back and make a half-inch incision to insert a thin ‘loading tube’ into the sacroiliac joint.

The device is then fixed in place before the tube is withdrawn.

The results of a recent study published in the Journal of Pain Research, involving 159 patients with chronic lower back pain aged 21 to 70, showed that one year after implantation, pain levels had dropped by more than 80 per cent in roughly a third of the patients.

Many others experienced a 50 per cent reduction in pain.

Patients’ mobility also improved. At the start of the trial, 82.1 per cent were severely disabled or bed-bound. After the trial, none was bed-bound and there was a three-fold drop in severe disability.

Commenting on the research, Mike McNicholas, a consultant orthopaedic surgeon at Liverpool University Hospitals, said: ‘Lower back pain due to sacroiliac joint pathology is a massive burden on society. This promising minimally invasive approach offers great hope to those suffering the problem and their carers and family who are also severely affected.’