Treatments

Introduction

Despite recent advances in medical treatment for osteoporosis, osteoporotic fractures remain a common problem and – with the increase in life expectancy and the aging population – the frequency of osteoporotic fractures and their associated treatment costs are expected to increase substantially.

Osteoporotic fracture in the spine remains subclinical (without clear signs) and progress is normally insidious. Some patients feel acute and severe pain. Traditional treatment of painful osteoporotic compression spine fracture includes bed rest, analgesics, bracing and physiotherapy. Most patients respond well to such conservative treatments but some suffer from protracted pain as well as permanent loss of mobility. 

Vertebroplasty is an image guided and percutaneous technique (one that uses needle-punctures to the skin) that injects the medical grade cement polymethylmethacrylate (PMMA) into a vertebral body that has the osteoporotic compression fracture. It is effective in stabilizing the spine fracture and helps prevent further collapse, thus helping to relieve acute pain. 

Anatomy

From a biomechanical point of view, a vertebral segment consists of three columns. Osteoporotic spine fractures usually occur in the anterior column, at the thoraco-lumbar junction – the stress point of axial loading. However, the fracture can also occur at other levels in the thoracic and lumbar spine. The location depends on the application of stress.

Cause

An Osteoporotic spine fracture usually occurs after a fall. The most common fall injury is a slip that leads to a landing on the buttock. The axial loading causes a compression fracture, usually at the thoraco-lumbar junction.

Symptoms

The most common symptom of osteoporotic spine fracture is severe back pain that will keep the patient in bed. The patient will not be able to tolerate sitting or walking and immobility in geriatric patients can result in various complications, including pneumonia, deep vein thrombosis, urinary tract infections and pressure sores. Prolonged immobility will only aggravate muscle atrophy and osteoporosis.

Some patients might also experience neurological complications such as numbness and weakness of the lower limbs. This is because of mechanical compression on the dural sac or the exiting lumbosacral nerve roots and may sometimes be associated with sphincter dysfunction (cauda equina syndrome).

Diagnosis

Physical examination of the spinal column for localized deformities such as acute kyphosis, area of local tenderness and swelling is essential to localize the pathology.

Fluoroscopy (X-ray) of the thoraco-lumbar spine will show features of a vertebral body collapse, a compression fracture and angular deformities. A magnetic resonance scan (MRI) is useful to rule out infective or malignant lesions while computer tomography scans (CT) assess the integrity of the posterior cortex of the involved vertebral body, a piece of useful information on the feasibility of vertebroplasty.

Non-surgical treatment

The goal is to control pain and to help the patient in ambulation and get out of bed. Common conservative treatment included rest, analgesics, bracing and physiotherapy. Calcitonin may have some analgesic effects in acute osteoporotic spine fractures.

Surgical treatment

If the back pain from the fracture is persistent and intractable after several weeks of conservative treatment, a surgeon may consider the option of vertebroplasty. Vertebroplasty (or kyphoplasty – see below) injects medical grade cement to strengthen the vertebral body after an acute osteoporotic fracture. It can be performed under local or general anesthesia. A cannulated needle system is inserted under image guidance to the vertebral body through the pedicle. Bone cement is injected while it is in the semi-fluid state to fill up the collapsed or compressed vertebral body. This stabilizes the segment when the cement hardens and will help the back pain. The image guidance would be fluoroscopic based, CT-based and computer navigation based. It is a minimally invasive procedure and usually gives immediate symptom relief.

Vertebroplasty is an extremely delicate procedure that requires the guidance of meticulous imaging or navigation. Possible complications are: leakage of cement into the spinal canal; damage to the neural structures causing neurological deficits; anaphylactic reaction to the cement and cement embolisation entering systemic circulation. Also, there have been reports that osteoporotic collapse in adjacent vertebral segments can be due to the shifting of stress after cement injection.

Kyphoplasty is a modification of vertebroplasty. The collapsed vertebral body is first expanded with an expansible balloon for kyphosis correction before injecting cement to fill up the vertebral body cavity.

Rehabilitation

Mobilization (sitting and walking exercises); ventilation exercises and muscle strengthening exercise programmes can be started immediately. 

Prevention

Various exercise programmes on fall prevention and maintainance of mobility are essential to prevent osteoporotic spine fracture. Adequate Calcium and Vitamin D intake is necessary to improve bone strength. Pharmacological treatment of anti-resorptive drugs such as bisphosphonates can reduce the risks of osteoporotic spine fracture.

Dr. KWOK, Kin-on