The back of the human being and of vertebrate animals is covered by a series of articulated bones whose function is to hold the entire bone skeleton, in addition to protecting and surrounding the spine. Between each of the vertebrae there is an intervertebral disc that acts as a shock absorber for the spine and is responsible for absorbing impacts when carrying out regular daily activities such as walking, running, jumping and allowing the spine to flex. The human spine differs from that of other mammals and animals in that it is the only one that has to support weight and activity directly against gravity, since humans are the only mammal that walks upright and bipedally.
The discs are shaped like a donut, composed of a hard annulus fibrosus on the outside containing a softer, gelatinous nucleus pulposus on the inside. When the human has to lift some weight or support a load, the discs act as shock absorbers, like the suspension in a car. The nucleus pulposus expands, releasing water in this process, thus spreading the load over the entire surface of the disc. The disk behaves elastically and returns to its initial state when the load is relieved. With age, discs can degenerate and the disc nucleus loses this elastic property, so the disc begins to lose height and the annulus fibrosus begins to crack due to the inability of the nucleus to distribute the load. This tends to occur more frequently in the cervical and lumbar region, since they are the ones that bear the most load and mobility and do not have the support of the ribs that act as a frame around the thoracic spine.
The most common pathologies of the spine include herniated discs, disc diseases due to degeneration and overload, idiopathic and degenerative scoliosis (acquired with age), etc. These conditions can lead to compression of the spinal cord and/or nerve roots that supply the arms and legs, which can cause radiating pain down the legs and arms, as well as severe back pain and severely limiting significant movement of people who suffer from them.
When an intervertebral disc is severely degenerated and causes severe pain that does not respond to conservative treatment (physiotherapy, anti-inflammatories, etc.), the solution is usually surgical. The surgery consists of replacing the disc with a titanium intersomatic cage, which allows the disc to be immobilized and its height restored, in addition to restoring the lordosis, that is, the curvature of the lumbar spine. If the surgery is successful, the pain immediately subsides and over time the adjacent vertebrae are joined by bone that grows through the operated box and disc, resulting in an intervertebral fusion.
In 10-15% of cases, fusion may not occur, for reasons as diverse as the quality of the patient’s bone (it is worse in women with osteoporosis, smokers, diabetic patients, etc.) and the cages may shift, causing at the same time that the screws that hold them loosen. This process known as pseudoarthrosis causes very intense pain in affected patients. These cases require revision surgery to remove the boxes and replace them with larger-area boxes to achieve bone fusion. A revision surgery of a migrated and/or pseudo-arthrotic cage is usually considered a complex surgery, since there is a greater risk of infection and of damaging a nervous structure due to the internal scar from previous surgeries.
When it comes to removing the intervertebral cages, the team of surgeons and researchers from the Morgenstern Institute of Spine (MIS) at the Teknon Medical Center has developed an innovative method. “This endoscopic surgical intervention is less invasive and reduces the risk of infection and nerve root damage. To date, spinal revision surgeries have been performed through an anterior or lateral approach to avoid going through scars from previous operations. The great innovation of this new technique is that the intervertebral cages can be removed through a small 2 cm incision and replaced by a larger one, if necessary, through the same incision” explains Dr. Christian Morgenstern, who points out that thanks to With this new technique, patients recover and are discharged from the hospital in a very short time.
During the extraction of the intervertebral boxes, it is essential to protect the nerve root that may be exposed during the operation, the MIS team has designed and patented a special instrument to protect the nerve root, “thanks to this instrument one of the greater limitations of endoscopic fusion surgery, the use of small specialized tools that can penetrate through the neuroforamen, the narrowing of the spinal canal,” says Dr. Morgenstern.
This technique has been carried out in patients previously operated on several times of the lumbar spine who suffered from intense back pain and pain radiating through the legs. After the endoscopic intervention, the pain subsided immediately and within a few hours, the patients were walking without pain, being discharged from the hospital the next day. This surgery is less invasive, avoids the internal scar from previous operations, and therefore there is minimal risk of infection or nerve root injury.
