Many treatments in the world of orthopedics involve removing or replacing damaged or injured tissue. We might “trim out” cartilage tears or perhaps “reconstruct” ACL tears by using other tissue, or we may even “replace” joints with artificial parts. However, in the world of Regenerative Medicine we try to augment the body’s own natural healing abilities to truly repair and heal the damaged tissue itself. We aim to actually cure the problem instead of just trying to come up with a second best solution. Utilizing the patient’s own stem cells is one of the most powerful tools that we have to achieve this.
Mesenchymal stem cells are produced in our bone marrow and they are responsible for healing connective tissues such as injured bone, ligaments, tendons and cartilage. As we get older or injured, we sometimes cannot get enough of these cells into the area in need of repair. This is especially true in and around joints and tendons where blood flow is poor or even non-existent. Since there is poor blood supply to these tissues, the stem cells have no way of reaching these tissues as they try to travel from the bone marrow to the site of injury. This is why injuries such as meniscal tears, labral tears, articular cartilage injuries, rotator cuff tears, ACL tears and many other orthopedic injuries fail to heal on their own. Stem cell procedures help solve this problem by precisely delivering a high concentration of stem cells into the injured area and aid your body’s ability to heal naturally. Patients experience very little down time and they typically avoid the long, painful rehabilitation periods that often follow surgery.
Let’s look at precisely how this is done. The first step is to harvest the bone marrow. This is usually performed through a needle aspiration from the pelvis. Typically anywhere from 1 to 6 needle aspirations are performed under local anesthesia yielding anywhere from 15cc to 120cc of a bone marrow aspirate. This bone marrow aspirate has the appearance of thick blood and is full of many different types of cells, the majority of which are NOT stem cells. Therefore, this bone marrow aspirate must be prepared in order to isolate and concentrate the stem cells. This process usually involves several steps of centrifuging, separating, purifying and reconstituting a mixture resulting in only a few milliliters of fluid containing millions of stem cells. Patients should be aware that there are many different systems available to do this and therefore all stem cell preparations are not the same. A final stem cell concentrate preparation may range anywhere from 5 million to 200 million stem cells. Ultimately the final concentration of the stem cells will depend on the type of system used as well as the age and health of the patient. Our stem cells are most robust prior to age 50 and will decline as we age. Therefore, the younger and healthier the patient, the better the stem cell sample we will end up with. Although there are many other factors, we do believe that ultimately the more stem cells we are able to concentrate and inject, the better the outcome will be.
Once the sample is prepared, we must then precisely inject it into the target tissue at the site of injury. Therefore it is crucial that this injection be performed under some type of guidance either using ultrasound or x-ray. It is also important for the stem cells to stay in the area of injury in order for them to do their job. Therefore often times the stem cell preparation may be combined with thrombin or another agent to make it into a sticky “paste” so that it can attach to the target tissue. After the procedure the target tissue may also have to be protected for a short amount of time and the patient may require a short duration of bracing or crutches so as not to disturb the stem cells.
We are still learning more and more about how exactly it is that the stem cells do their job of healing in the first place. We initially believed that the stem cells actually become or “grow into” the new tissue itself (cartilage, tendon, etc). However, this may not actually be the case. It may be that the stem cells somehow communicate and interact with the damaged tissue to induce those cells to heal themselves. Therefore, we are learning that it is the communication between the stem cells and the surrounding injured tissue that is most important and creating the right environment for them to do their job is essential. That is why often times platelet rich plasma or other biologic solutions may be injected in conjunction with the stem cells in order to provide growth factors and other cellular communicating functions to continue to instruct the stem cells how to heal the damaged tissue.
The take home message is that all stem cell treatments are not the same. The method of collection, preparation, delivery and providing the right environment for the stem cells can all have significant influence on the success or failure of the procedure. Patients should be educated and ask insightful questions from their healthcare providers in order to ensure that they are receiving the best possible treatment for their injury.
The use of stem cells in the world of orthopedics is an evolving science which is still in its infancy. It holds tremendous potential to naturally heal many injuries which may otherwise require more invasive surgeries with long recoveries. However, there are still many unanswered questions regarding this science and since these procedures are often expensive and are still regarded as experimental by most insurance carriers, they typically require large out of pocket costs to the patient and it is therefore important for the patient to be well educated in choosing a procedure that is right for them.