The medical term spondylodesis describes a surgical spinal fusion. In this surgical procedure, two vertebrae are stiffened together. The resulting loss of motion remains permanent and cannot be reversed.
What is spondylodesis?
The medical term spondylodesis describes a surgical spinal fusion. In this surgical procedure, two vertebrae are fused together. Spondylodesis is among the invasive forms of therapy for certain types of severe back pain as well as spinal deformities. Surgical fusion of the spine is performed either partially or completely, depending on the indication. The extent of the fusion determines the subsequent mobility between the vertebrae. Since several vertebral bodies are connected with the help of plates or screws during spondylodesis, they can no longer perform their joint function. Spinal fusion is a very complex and large operation on the back. After the operation, it is no longer possible to bring about an improvement in the body’s statics. Due to the irreparable result, this form of therapy is often the last option for the patient to improve the symptoms. Therefore, in almost all cases, fusion surgery is performed only when neither conservative treatment measures such as physiotherapy, manual therapy, muscle building training or back school, nor other measures such as injections, as well as medication, have been able to bring about an acceptable improvement in the symptoms.
Function, effect, and goals
Spondylodesis is performed due to severe spinal disorders. In cases of pronounced scoliosis or serious spinal injuries after an accident, as well as severe degeneration of bone structures, fusion may be used. Fusion also reunites the vertebrae in the case of a vertebral fracture. Spondylodesis has the effect of maintaining the stability of the spine. In addition, important structures such as the spinal cord and aorta are protected. Endangerment of internal organs can also be averted by fusion. In this way, not only pain disorders but also neurological deficits can be treated. Surgical spinal fusion always takes place under general anesthesia. Only if no implants have to be inserted, spondylodesis can be performed minimally invasively. This method ensures that both skin and soft tissues are minimally injured during access. The use of the special instruments is controlled by imaging techniques during the operation. The invasive surgical technique itself is performed from the back, with the back muscles pushed to the side. Through this access, the surgeon reaches the vertebral bodies that are to be stiffened. Titanium screws are used here, which are connected to longitudinal rods. Bone removal is performed when nerve roots are constricted by the vertebrae. In order to maintain the bony stiffening, bone structures are attached to the so-called transverse processes. The bone mass needed for this is taken from the posterior part of the iliac crest. In some patients, it is necessary for metal baskets to be inserted into the vertebral space where the disc is located, in conjunction with bone. Both screws and rods ultimately cause the bones to grow together permanently. Later removal of the metal can be avoided as far as possible. The duration of the operation depends on the extent of the spinal fusion. While the duration of a minimally invasive spinal fusion can be less than an hour, a long spinal fusion can take up to several hours. Nowadays, the goal of fusion is achieved in over 95% of all cases. Using the most modern surgical techniques, such as the bone attachments and screw fixations, successful fusion of the vertebrae can almost always be ensured.
Risks, side effects and dangers
Because spondylodesis is a very large operation in most cases, there are risks to the cardiovascular system on the one hand. On the other hand, wound infection occurs in about one percent of those who undergo surgery. In principle, complications occur rather rarely. Nevertheless, nerve injuries can occur, since in most cases constricted nerve fibers have to be exposed in the course of a fusion.Damage to the nerves in the spinal cord can have severe consequences: Sensory disturbances and restrictions of motor abilities are possible. Only very rarely, however, do the inserted screws affect the nerve roots. If damage does occur, the nerve usually recovers completely after some time. Nevertheless, there remains a minimal risk of developing permanent foot or leg weakness. The risk of total body paralysis can be ruled out. It is almost impossible for patients to be dependent on a wheelchair after undergoing lower back spondylodesis. Occasionally, the vertebrae do not fuse together adequately. The screws can then loosen and cause pain again. Heavy smokers in particular are frequently affected by this complication. In addition, it is possible that implant damage such as material fractures may occur during or after fusion. To correct these problems, the spine must be operated on again. Since patients who have undergone surgery are allowed insufficient movement within the first eight weeks after the procedure, the risk of developing thrombosis is increased. Also, due to the use of the necessary urinary catheter, urinary tract infection may occur if worn for a longer period of time. Following surgery, patients often complain of back pain. These are caused by the operation itself, as tissue structures are injured in the process. Unpleasant wound healing pain also occurs. In a spondylodesis, the surgeon makes a very long incision. If the scar heals poorly, adhesions or growths may occur. These can cause long-term discomfort. This is different with minimally invasive surgery, which results in only smaller wounds.
