Spinal fusion is an invasive form of therapy for certain forms of severe back pain and changes in the spine. Depending on the indication, the surgical stiffening of the spine is carried out either partially or completely. The extent of the stiffening determines the subsequent mobility between the vertebrae. Since several vertebral bodies are connected using plates or screws during spondylodesis, they can no longer perform their joint function.

A spinal fusion is a very complex and major operation on the back . After the procedure, it is no longer possible to bring about an improvement in body statics. Due to the irreparable result, this form of therapy is often the patient’s last chance to improve the symptoms. 

Therefore, in almost all cases, a stiffening operation is only carried out when neither conservative treatment measures such as physiotherapy , manual therapy, muscle building training or back school nor other measures such as injections or medication have been able to bring about an acceptable improvement in the symptoms.

Function, effect & goals

Spinal fusion is performed due to serious spinal conditions. The stiffening can be used in the case of pronounced scoliosis or serious spinal injuries after an accident, as well as in the case of severe deterioration of the bone structures . Even in the event of a vertebral fracture, the stiffening brings the vertebrae back together again.

The spondylodesis ensures that the stability of the spine is maintained. In addition, important structures such as the spinal cord and aorta are protected. The endangerment of internal organs can also be averted by stiffening. In this way, not only pain disorders but also neurological deficits can be treated.

The surgical stiffening of the spine always takes place under general anesthesia . Spinal fusion can only be performed minimally invasively if no implants need to be inserted. This method ensures that there is minimal trauma to both skin and soft tissues during access. The use of the special instruments is controlled by imaging procedures during the operation.

The invasive surgical technique itself is performed from the back, with the back muscles being pushed to the side. This access allows the surgeon to access the vertebral bodies that are to be stiffened. Titanium screws are used here, which are connected to longitudinal rods. Bone removal occurs 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 required for this is taken from the rear part of the iliac crest. In some patients it is necessary that metal basket in the vertebral space where the disclies, are introduced in connection with bones. Both screws and rods ultimately cause the bones to grow together permanently. Subsequent metal removal can largely be dispensed with.

The duration of the operation depends on the extent of the spinal fusion. While the duration of the procedure for a minimally invasive splinting is sometimes less than an hour, a long spondylodesis can last up to several hours. Today, the goal of stiffening is achieved in over 95% of all cases. Successful fusion of the vertebrae can almost always be ensured using the latest surgical techniques such as bone attachment and screw fixation.

Risks, side effects & dangers

Since spondylodesis is a very large operation in most cases, there are risks for the cardiovascular system on the one hand . On the other hand, a wound infection occurs in about one percent of those who have been operated on. Complications are generally rare. Nevertheless, nerve injuries can occur, since in most cases constricted nerve fibers have to be exposed as part of a stiffening.

Damage to the nerves in the spinal cord can have serious consequences: sensory disturbances and limitations in motor skills are possible. However, only very rarely do the screws used 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 excluded. It is almost impossible for patients to be confined to a wheelchair after undergoing lower back spinal fusion.

It happens that the vertebrae do not grow together sufficiently. The screws can then loosen and cause pain again. Heavy smokers in particular are more frequently affected by this complication. In addition, it is possible that damage to the implant, such as material fractures, occurs during or after the stiffening. To correct these problems, the spine must be operated on again. 

Since the operated patients are not allowed to move sufficiently within the first eight weeks after the operation, the risk of developing a thrombosis is increased. The use of the necessary urinary catheter can also lead to a urinary tract infection if the device is worn for a longer period of time.

Patients often complain of back pain after the operation. These are caused by the procedure itself, as tissue structures are injured. In addition, unpleasant wound healing pains arise. In a spinal fusion, the surgeon makes a very long incision. If the scar heals poorly, adhesions or growths may appear. These can cause long-term problems. This is different with a minimally invasive procedure, in which only small wounds occur.