Vertebroplasty for Osteoporotic Vertebral fracture
by Mr. K P Muralikuttan FRCS Tr. & Orth.
Calderdale Royal Hospital, Halifax, West Yorkshire HX3 0PW
120,000 osteoporotic vertebral fractures occur annually in the United Kingdom. A third of these patients continue to have significant pain requiring narcotic analgesics even at three months. Bed rest make the osteoporosis worse due to further bone loss in these patients. Vertebral wedge compression fractures often lead to increasing kyphosis and can have an adverse effect on respiratory function. These patients have increased risk of further fractures and have a higher mortality.
Assessment of patients with osteoporotic vertebral fractures must include a thorough neurological examination, radiological study of the deformity and consideration of risk factors for osteoporosis. Often the plain radiographs are insufficient to assess these fractures. MRI scan can show marrow signal changes, fracture comminution, canal compromise and cortical disruption.
Treatment plan must include medical management of osteoporosis as well as treatment of the osteoporotic vertebral fractures. Continued pain after three months of the fracture, radiculopathy with or without neurological deficit, spinal decompensation from deformity, and significant aggravation of respiratory function all indicate failure of conservative management. Surgical intervention is considered in such situations. The standard approach to this problem involves spinal decompression and fusion. However reduced fixation strength due to the osteoporosis can cause implant failure and adjacent vertebral fractures.
Vertebroplasty
Vertebroplasty is an alternative surgical option for management of patients with osteoporotic vertebral fractures. Vertebroplasty is defined as the percutaneous augmentation of vertebral body volume and strength by injection of a hardening material in a liquid state. The procedure of injecting bone cement into the vertebra was initially tried in painful vertebral body tumours more than twenty years ago. Success of the procedure led to extension of its application to osteoporotic vertebral fractures.
Vertebroplasty reduces the duration of acute pain due to osteoporotic fracture, helps to reduce the use of analgesic medication, decreases the chance of further collapse of the vertebral body and improves the mobility of the patient. In majority of patients the pain relief is quick and complete.
Indications and contra-indications
Painful spinal metastasis with intact posterior cortex, chronic non-united vertebral compression fracture and progressive early kyphosis following vertebral fracture are considered definite indications for vertebroplasty. Relative indications include sub acute fractures with persistent pain, acute vertebral fractures with more than 40% collapse of the height of vertebra or with more than 20 degree kyphosis and acute wedge compression fractures in patients with kyphosis due to previous fractures.
When the vertebra is completely collapsed with loss of more than two thirds of the vertebral body height or when there is spinal canal compromise, the procedure is contraindicated. Breach of the posterior vertebral cortex is also a contraindication for the procedure.
Technique
Vertebroplasty is done as day case under general anaesthesia (local anaesthesia with sedation is an alternative). Low viscosity cement is injected into the vertebral body through a special large bore needle inserted through the pedicle percutaneously. Cement sets in 15 to 20 minutes and patient can be mobilised and discharged home on the same day. Most patients can progressively return to normal activity within days or weeks.
Results
Improvement in the pain level is reported in 75 to 100% of patients following vertebroplasty for osteoporotic vertebral fractures. In bone tumours the reported success rate is just under 75%. In most patients the pain relief is maintained for a period of six months or more. Early vertebroplasty within three months of a fracture helps to regain vertebral body height in 70% of cases.
The main shortcoming of vertebroplasty is the inability to restore vertebral body height if the procedure is done once the fracture is immobile. Because cement is injected under pressure, there is a risk of leakage of cement into the spinal canal if the posterior vertebral cortex is breached by the fracture.
Kyphoplasty
Kyphoplasty is designed to remedy these shortcomings. In kyphoplasty, a balloon is passed into the vertebral body by percutaneous transpedicular approach. Inflation of the balloon creates a space in the vertebral body into which cement is injected without pressure through a cannula. This helps to reduce the risk of leakage of cement into the spinal canal. The expansion of the balloon also helps to correct deformity by restoring the vertebral height.
Complications
Complications are uncommon following vertebroplasty. Cement leakage into the spinal canal can produce serious neurological consequences. Fat embolism, CSF leak due to inadvertent dural puncture, pulmonary embolism due to cement embolisation, bleeding and infection are other rare reported complications. There is also increased risk of fracture of adjacent vertebral bodies following strengthening of one or more osteoporotic vertebrae by percutaneous cement delivery.
Summary
Vertebroplasty is a safe and effective minimal invasive method of treatment of osteoporotic vertebral fractures and vertebral body tumours. With the increasing prevalence of osteoporotic vertebral fractures due to increase in the percentage of elderly population in the United Kingdom, vertebroplasty is gaining increasingly important role in management of osteoporotic vertebral fractures.
Reference
1.Hadjipavlou A G, Tzermiadianos M N, Katonis P G and Szpalski M. Percutaneous vertebroplasty and balloon kyphoplasty for the treatment of osteoporotic vertebral compression fractures and osteolytic tumours. JBJS 2005; 87-B: 1595-1604.
