What is the difference?
With the introduction of new technologies in medicine, understanding each new technique is becoming more and more difficult. Minimally invasive procesdures are in full bloom and the spine is benefiting from these advancements. One area that can be confusing are the treatment choices for spine compression fractures. The 2 terms often mentioned include Vertebroplasty vs Kyphoplasty. People with compression fractures secondary to osteoporosis or tumor, oftentimes have multiple other diseases. The need for a procedure that was minimally invasive, offered little blood loss and allowed immediate wight bearing was in great demand. Vertebroplasty was introduced in the late 80’s as a technique to stabilize these problematic fractures.
Vertebroplasty is a procedure that introduces a needle via a bony tunnel into the front of the spine. The vertebral body (anterior portion of the spine bone) is the weight bearing portion of the spine and undergoes collapse with fractures. Vertebroplasty allows for the injection of a polymer (bone cement) through these bony tunnels into the vertebral bone and hardens. The cement hardens over a period of 12-15 minutes secondary to a chemical reaction. Once the cement is hard, the bone is stable and immediate weight bearing can be performed.
The problems with vertebroplasty are twofold. The first is the liquid cement will follow the path of least resistance. Best case scenario involves the hard outer surface (cortex) of the bone being intact. If there is any discontinuity of the cortex, there is a risk of cement leakage into the spinal canal or into the abdomen or chest. The second issue is the cement fixes the spine in a collapsed position. We are all familiar with patients who progressively “hunch over” with time secondary to multiple fractures. This procedure does not address the deformity issue.
Kyphoplasty was developed with the help of orthopedic surgeons to address the deformity issue. One of the basic tenants of Orthopedics is to obtain a reduction of the fracture. In other words, “If it’s bent, straighten it out.” Kyphoplasty is similar to vertebroplasty in that initially a needle is introduced into the vertebral body. Over this needle a small tube is inserted. Through this tube a balloon is placed into the body and slowly inflated. With young fractures, the balloon will inflate the collapsed vertebrae. Oftentimes, this improvement in alignment will minimize “hunching over” (kyphosis) that appears. More importantly, the balloon will create a space in the bone as it inflates. This forms a bone “hole” which is of low resistance. The balloon is then removed and cement added through this tube. The cement follows the path of least resistance which is the bone “hole”. This minimizes unintended leakage of cement from the vertebral body.
To summarize, there are two techniques which allow surgeons to treat compression fractures. Both involve needle placement into the spine and stabilization of the fracture with “bone cement”. Only one allows for improvement of the deformity that is associated with these fractures and only one creates a “bone hole” to allow for safer placement of the liquid cement. That option is kyphoplasty.