Vertebral body alignment, balloon dilatation, cementing of the vertebral body
Definition
Vertebroplasty: Vertebral body stabilization for vertebral body fractures, or prophylactically for imminent vertebral body fractures, by inserting bone cement without ballooning the vertebral body. Kyphoplasty: Vertebral body stabilization for vertebral body fractures, or prophylactically for impending vertebral body fractures, by introducing bone cement with balloon erection of the vertebral body. Both methods of vertebral body stabilization (kyphoplasty and vertebroplasty) are modern surgical procedures for treating collapsed (sintered) vertebral bodies in the thoracic and lumbar spine.
They are currently not used on the cervical spine. In contrast to vertebroplasty (1987), which was originally developed for the treatment of vertebral hemangiomas, kyphoplasty (1998) was developed specifically for the treatment of osteoporotic vertebral body fractures. The majority of patients with osteoporotic vertebral body fractures are symptom-free thanks to adequate pain and physiotherapy.
However, 10-20% of patients suffer from chronic back pain. After exclusion of other causes, these patients have the indication for a pain-reducing kyphoplasty or vertebroplasty. Vertebroplasty and kyphoplasty are successfully used for the following diseases:
- Fresh osteoporotic vertebral body fractures (spontaneous fractures)
- Fresh traumatic vertebral body fractures
- Neoplastic vertebral body incursions (tumors or metastases)
Approximately 5 million people in Germany suffer from pathological bone loss (osteoporosis).
Vertebral body fractures are one of the most common complications of advanced osteoporosis. Those affected suffer from severe acute or chronic back pain, which in the past was usually treated conservatively with painkillers or orthoses (bodices, corsets). With kyphoplasty, a successful surgical method is now available that restores the structure and stability of the vertebral body and thus leads to a considerable reduction in pain, as well as preventing further collapse of the previously damaged vertebral body.
The possibility of kyphoplasty, however, does not replace a systemic osteoporosis therapy! The most common site of fracture formation is the thoraco-lumbar transition, i.e. the transition from thoracic spine curvature (kyphosis) to lumbar spine curvature (lordosis). Due to the change in curvature of the spinal column, the vertebral bodies are subject to particular stress, which explains the increased incidence of vertebral body fractures in this area.
Traumatic vertebral body fracture differs considerably from osteoporotic vertebral body fracture. While osteoporotic vertebral body fractures usually occur spontaneously, insidiously, or after a minor injury, traumatic vertebral body fractures are based on a significant degree of violence. Accordingly, the types of fractures also differ, although traumatic vertebral body fractures are much more complex and have a much higher incidence of severe concomitant injuries such as spinal cord, intervertebral disc or ligament injuries.
Complex vertebral body fractures and those with significant concomitant damage cannot be treated by means of kyphoplasty surgery. In such cases, extensive stabilizing surgical procedures are always necessary. In general, kyphoplasty is not yet routinely used to treat traumatic vertebral body fractures.
There is too little long-term experience to date to develop a standard for the use of this procedure in traumatic vertebral body fractures. However, the best conceivable vertebral body fracture form is certainly the fresh, stable compression fracture of a vertebral body without further accompanying injuries. Experience with osteoporotic vertebral body fractures has shown that it would be advisable to perform surgery early, because experience shows that only then can the compressed vertebral body be satisfactorily repositioned.
Vertebral body fractures involving the posterior edge of the vertebral body (in the direction of the spinal cord) are a contraindication for the use of kyphoplasty and vertebroplasty. Vertebroplasty was developed to stabilize hemangioma vertebrae (benign vertebral body tumor, based on proliferating vascular growth). Its use has proven successful.The use of kyphoplasty for malignant (malignant) tumors is mainly seen in disseminated (scattered) tumor infestation by osteolytic (bone-dissolving) tumors, when surgical healing in the spinal region is no longer possible.
Authors refer to the theoretically possible venous seeding of malignant vertebral body tumors when the tumor mass is displaced by the balloon catheter. A major advantage is the relatively small intervention and thus the almost instantaneous possibility of continuing ongoing radiation or chemotherapy. Two different surgical techniques are described for kyphoplasty, which differ mainly in their surgical access route to the vertebral body: The microsurgical “half-open” technique is used in cases of concomitant diseases that are difficult to treat or difficult anatomical conditions in the surgical field.
The operation is performed under general anesthesia via a 5 cm long incision. Due to the better intraoperative visibility, concomitant injuries can be treated or complications, such as an unintentional bone cement leakage into the spinal canal, can be corrected immediately. Disadvantages are the greater soft-tissue trauma and thus the somewhat longer recovery time for the patient as well as the necessity of general anesthesia.
With the percutaneous technique, surgery can be performed under both general and local anesthesia. All the surgical steps described below are performed on both sides in chronological order. Under X-ray control, a hollow needle is inserted into the fractured vertebral body from the back through a stab incision (1-2 cm long skin incision).
A guide wire is inserted through this hollow needle, which acts as a guide rail for the now inserted working channel. When placing the working channel, care must be taken to ensure that the vertebral body wall is not injured, as otherwise the bone cement injected later could escape. A drill is used to create a bearing in the vertebral body for the kyphoplasty balloon, then the kyphoplasty balloon is inserted.
The balloon is gradually filled with contrast medium and the collapsed vertebral body is lifted until a satisfactory correction is achieved. Once vertebral body alignment has been achieved, the balloon is removed. It leaves a bony cavity, which is filled with viscous bone cement (PMMA=polymethyl methacrylate) under low pressure.
The filling volume depends on the last achieved volume of the kyphoplasty balloon (approx. 8-12 ml). The duration of the operation depends on the number of vertebral bodies operated on.
If only one vertebral body has been operated on, the operation time is approx. 30-45 minutes. Patients are fully mobilized the day after surgery.
The significant pain reduction is usually immediate. In vertebroplasty, the vertebral body is filled with bone cement without prior balloon erection. Because no bony cavity has been created beforehand, the thin-bodied bone cement must be injected under high pressure into the vertebral body so that it can be distributed in it.