The bone cement placed into the spine to either anchor metal or plastic
Prosthetic parts to bone or used alone in the spine for treating osteoporotic
Compression fractures.
Bone cement has been used successfully to fix artificial joints for more than half
a century. Artificial joints also called prostheses, anchored with the help of bone
cement and sometimes screws and metal rods can also be used to fix the joints. Historically bone cement was first used by Themistokles Gluck in 1870, to fix a total knee prosthesis made of ivory with help cement made of plaster and colophony. However, this bone cement plays a prominent role now in spine
surgeries too.
The two main groups of bone cement are acrylic bone cement and calcium phosphate bone cement. Mostly they are used either in vertebroplasty or kyphoplasty procedures.
Types of Bone Cement
There are different types of bone cement classified based on its viscosity. The characteristics of bone cement such as handling time, the penetration into the bone and the quality and longevity of the fixation depend on its viscosity. Optimum viscosity of the cement helps achieve the best results.
The two requirements for bone cement to be noted are viscosity during the working phase – viscosity should be low enough to deliver the cement from the injection to the bone site – it must penetrate into the spaces of the bone. The viscosity should also be high enough to resist the back bleeding pressure to avoid the risk of blood flow into the cement.
Various types of bone cement are classified according to their viscosity include:
Low viscosity cement: These types of cement remain in a runny state for a long time compared to medium or high viscosity cement. Typically the waiting phase is long, and the setting time also varies.
Medium viscosity cement: These types of cement have the adaptability to various kinds of procedures. Medium viscosity cement has both low and high in viscosity nature, depending on the time of delivery of the cement. So they are considered as dual-phase cement.
High viscosity cement: These types of cement primarily are composed of PMMA with no copolymer content, and they don’t have a runny state. Immediately after mixing, they are ready to apply. High-viscosity cement (HVC) is being implemented in percutaneous vertebroplasty and percutaneous kyphoplasty procedures. High viscosity cement when used is injected using a pressure device. It has low extravasation chance.
Antibiotic Cement: All antibiotics are not suitable to use in bone cement. A lot of factors come under consideration like bacteriologic, physical and chemical factors to mix antibiotics in the bone cement. Implantation of antibiotic cement permanently helps in preserving spinal instrumentation and spinal Fusion during infection eradication. It helps to prevent infection recurrence and reduces operative debridement’s.
What Is Bone Cement Made Of?
Bone cement comprised of two components powder ( polymethyl methacrylate (PMMA), amorphous powder ) and liquid (MMA monomer, stabilizer) that begins to harden when mixed. The viscosity of bone cement changes over time after mixing from a runny liquid into a rough state that can be safely applied and then finally hardens into a solid material. They can be injected into the spine to treat osteoporotic compression fractures.
When Bone Cement First Used In Spine?
Galibert et al was the first surgeon to use PMMA bone cement in 1987 to treat cervical vertebral haemangioma condition. Since then, this method has been successfully used to many spine disorders which includes OVCFs, vertebral metastasis of tumours, myeloma, and traumatic VCFs etc.
How long does bone cement take to set?
Under typical conditions, it takes 2-3 minutes after mixing for most bone cement to achieve suitable viscosity for handling. After mixing of the components, the bone cement might be loaded into a syringe or cartridge or injection gun for assisted application.
What is BCIS(bone cement implantation syndrome)?
BCIS is defined by hypoxia or hypotension and unexpected loss of consciousness at the time of cementation, prosthesis insertion, joint reduction and occasionally, limb tourniquet deflation in people who are undergoing cemented bone surgery.
Are There Any drawbacks In The Use Of Bone Cement?
According to the FDA, PMMA bone cement, used in vertebroplasty and kyphoplasty procedures, may leak those results in soft tissue damage and nerve pain and compression.
Can bone cement be removed?
Yes, when bone cement injected in the spine causes any discomfort, typically it can be removed by various techniques including cutting, scraping, or piecemeal removal.
How Efficient Is Bone Cement In Spine Procedures?
The population of the elderly is increasing rapidly, and instances of degenerative spinal conditions also increasing that accompany osteoporosis which includes spondylolisthesis, intervertebral disk bulge, spinal canal stenosis and vertebral compression fractures.
These conditions influence the reduction of bone quality and the stability of your spine. These conditions cause lower back pain or radiating pain in your lower limbs and also limits. Many methods were used for internal fixation, including rods and instrumentation. Pedicle screw instrumentation is a common procedure for posterior fixation of vertebrae.
However, when these screws are used to treat osteoporotic spine, the strength of the screws decreases due to low bone density, resulting in loosening and pull out of screws. The screw fixation in patients with osteoporosis becomes challenging for spinal surgeons. In such cases, bone cement is considered as the most efficient method in this field. There are screws with cannulation which allow the cement to be placed inside to enhance the fixation of the implant in the bone.
