kyphoplasty

Terms: straightening of the vertebrae, balloon dilatation, cementation of the vertebrae.

Vertebroplasty: stabilization of the spine in case of vertebral fractures, or preventive stabilization in case of threatened fractures, by injection of bone cement without the use of balloon dilatation.

Kyphoplasty: stabilization of vertebrae in case of fractures or prophylactic stabilization in case of a risk of fracture by injection of bone cement using balloon dilatation.

Causes

Both methods of vertebral stabilization belong to modern surgical technologies used in the treatment of damaged vertebrae in the thoracic and lumbar regions. There is currently no treatment for the cervical spine.

In contrast to vertebroplasty (1987), which was originally developed for the treatment of vertebral hemangiomas, kyphoplasty (1998) was created, which was developed specifically for the treatment of osteoporotic vertebral injuries.

Most patients with osteoporotic vertebral fractures are relieved of pain by this adequate method of physiotherapy and pain therapy. However, 10-20% patients still suffer from chronic back pain.
After ruling out other causes, the patient may opt for a pain-reducing kyphoplasty or vertebroplasty procedure.

Vertebroplasty and kyphoplasty are successfully used in the treatment of the following diseases:

• fresh osteoporotic fractures of the vertebrae (spontaneous fractures);
• traumatic fractures of the vertebrae;
• neoplastic injuries of the vertebrae (tumors and metastases).

1.Osteoporotic vertebral fractures

About 5 million people in Germany suffer from painful atrophy of the bones (osteoporosis). Diseases of the vertebrae are among the most common complications in progressive osteoporosis. Those susceptible to this disease suffer from severe acute or chronic back pain, which was previously treated mostly conservatively with analgesics or orthopedic devices (corsage, corset).

To date, kyphoplasty is a successful surgical treatment at the disposal of doctors, which restores the structure and stability of the vertebra and, as a result, leads to both a significant reduction in pain and the prevention of further damage to the vertebra.

However, the possibility of kyphoplastic treatment of the vertebrae in no way replaces the systematic treatment of osteoporosis!

The most common location for fractures is the transthoracic-lumbar junction, i.e. the transition from the curvature of the thoracic spine (Kyphose) to the curvature of the lumbar spine (Lordose). Due to the change in the curvature of the spine, there are special loads on the vertebrae, which in this case explain the increased incidence of vertebral fractures in this area.

2. Traumatic fractures of the vertebrae (caused by an accident)

Traumatic vertebral fractures are significantly different from osteoporotic vertebral fractures. While osteoporotic vertebral fractures occur mostly unexpectedly, slowly developing or after minor injuries, traumatic vertebral fractures are based on a significant force effect.

In accordance with this, the types of fractures also differ, and traumatic fractures of the vertebrae can reach much more complex fractures of the spine and incomparably more severe concomitant injuries, such as dysfunctions of the spinal cord, dysfunctions of the intervertebral discs or damage to the ligaments. With such complex vertebral fractures and such significant associated injuries, kyphoplasty alone does not lead to a complete cure. In such cases, extensive stabilizing operating techniques are always needed.

In general, kyphoplasty is not yet routinely used in the treatment of traumatic vertebral fractures. To date, there are too few long-term experiences in which a standard could be developed for the application of this process to traumatic vertebral fractures.

However, the ideal form of a vertebral fracture appears to be a fresh, stable vertebral compression fracture with no further associated injury.

The ideal option, worth mentioning, and this is shown by experiments with osteoporotic fractures of the vertebrae, would be to perform the operation as early as possible, since it is known from experience that only then is a satisfactory recovery of the compressed spine possible. Vertebral fractures involving the posterior edge of the vertebrae (in the direction of the spinal cord) are an absolute contraindication for kyphoplasty and vertebroplasty.

3. Neoplastic injuries of the spine

Vertebroplasty was developed to stabilize vertebral hemangiomas (benign tumors of the vertebrae that form due to increased vascular enlargement). Its use has worked well.

The use of kyphoplasty in malignant tumors is considered as a method mainly for disseminated (disseminated) lesions caused by osteolytic (softening) bone tumors, if surgical treatment in the spinal region is no longer possible.
The authors point to a theoretically possible malignant venous breeding ground for tumors on the vertebrae when the tumor mass is displaced by a balloon catheter.

The big advantage is the relatively small surgical intervention and, as a result, the almost immediate possibility to continue the current radiation or chemotherapy.

Diagnostics

For kyphoplasty, 2 different surgical techniques have been described, which differ mainly in the operational approach to the spine.

The microsurgical "semi-open" technique is used in case of concomitant diseases that make the operation difficult or difficult anatomical conditions in the area of the operation.

The operation is performed through a 5-centimeter incision under full anesthesia. Due to the better operating picture, it is also possible to immediately treat concomitant diseases or complications, such as undesirable protrusion of bone cement into the spinal canal. More unfavorable are large soft tissue injuries and, as a result, a slightly longer rehabilitation time for the patient, as well as the need for general anesthesia.

The technique of surgery through the skin can be used both under general anesthesia and under local light anesthesia.

All of this following operational steps occur bilaterally in time sequence.

When using X-ray as a control observation during the operation, a hollow needle is inserted from the back into the damaged vertebra (skin incision 1-2 cm).

A mandrel is inserted through this hollow needle, which acts as a guide bar for the inserted working channel.

Care must be taken during the working placement of the canal to ensure that no damage to the vertebral walls occurs, otherwise the injected bone cement may later leak out.

With the help of a drill, a space is created in the vertebra for a kyphoplastic balloon, which is then placed there. Gradually, the balloon is filled with a contrast agent until a satisfactory level of vertebral correction is achieved. After the restoration of the vertebra is achieved, the balloon is removed. It leaves behind a bone cavity which is filled with viscous bone cement (PMMA=polymethyl methacrylate) using low pressure. The filling volume is determined by the final volume of the kyphoplastic balloon (8-12 ml).

The duration of the operation is determined by the number of operated vertebrae. With one operated vertebra, the operating time is 30-45 minutes. Patients are fully mobilized the very next day after surgery. As a rule, a clear decrease in pain is immediately observed.

In vertebroplasty, the vertebrae are filled with bone cement without first being filled with a balloon. Since the bone cavity was not created in advance, liquid bone cement must be injected at high pressure into the vertebrae in order for it to be distributed there.

Treatment

Kyphoplasty:

• very low operational risk;
• recommended indications for older and more recent injuries of the vertebrae in order to restore the vertebrae;
• restoration of the height of the vertebra with a balloon catheter;
• stabilization of the vertebra with bone cement;
• the risk of cement leakage is much lower, due to the pre-created cavity and low pressure when filling the vertebra with viscous bone cement;
• faster, significant pain relief in 80-95% patients;
• immediate mobilization after surgery is possible.

Vertebroplasty:

• low-risk surgery;
• indications for certain forms of vertebral tumors and older fractures for stabilization without vertebral reconstruction;
• lack of preliminary creation of a bone cavity with a balloon catheter;
• stabilization of the vertebra with bone cement;
• higher risk of cement leakage due to injection under high pressure;
• faster, significant pain relief in 80-95% patients;
• immediate mobilization after surgery is possible.