Vertebroplasty versus Kyphoplasty
(author: Thammo Weise)

Both minimal invasive procedures are undisputedly methods which because of their effective pain reduction have revolutionised the therapeutic concept for osteoporosis related vertebral compression fractures. Besides the purely pecuniary fact that Kyphoplasty instruments cost five to ten times as much as those for Vertebroplasty, there are several other aspects which also deserve close consideration:

The rate of straightening of kyphosis into the approximately pre-fracture form originally propagated by Kyphon has been put into perspective by numerous studies. In many cases involving recent fracture (6-8 weeks) straightening is possible, but often by only a few millimetres or degrees depending on the age of the fracture. However, it has now also been found that hyperlordotic positioning alone also makes it possible for Vertebroplasty to reduce the angle of kyphosis by two to three degrees. Since this fact is not attributed primarily to Vertebroplasty as a pure pain therapy, however, in most cases no attention at all is paid to measuring the change in the angle of kyphosis pre- and postoperatively. In view of the DRG codes, which remunerate vertebral redressement depending on the instruments used (OPS 5-839.a... vs. OPS 5-839.9...), remuneration based on the actual success of treatment is recommended under the circumstances described.

The correction of the billing modalities since 2007 has meant that Vertebroplasty has become much more economical than Kyphoplasty both for hospitals and for health system. With the same diagnosis, an adequate procedure (number of vertebrae treated), taking into account the set costs and minimum hospitalisation time and assuming that the clinical background conditions, such as imaging, team and intervention time are identical, the balance works out clearly in favour of Vertebroplasty.

Many research groups can demonstrate with evidence that the leakage risk and thus the potential for an intervention related complication are lower with Kyphoplasty. On the one hand, this will certainly be due to the compaction of the trabecular structure as a cement barrier by the expansion of the balloon and the professional support provided by the manufacturer for all treatments by inexperienced users. On the other hand, the experience of well versed physicians shows that the choice of excellent - in terms of resolution and position relative to the patient - imaging and the application of a high-viscosity cement due to the polymerisation process using an injection system can achieve similar results to those of Kyphoplasty. Nevertheless, the presumed safety aspect is the decisive argument for many users. However, it should be noted that by far the highest proportion of leakages remain clinically silent and have no impact on the patient. Scientists of RWTH Aachen University have recently studied the intervertebral pressure conditions in both procedures in human specimens. It was found that during the injection of an identical quantity of cement the pressure conditions are significantly higher during Vertebroplasty and that the pressure in a kyphoplastied vertebra only rises after the cavity has been completely filled with cement. This study, however, does not disprove the higher leakage potential with burst or split fractures which can develop only to a certain extent due to the cement application and much more probably because of the balloon dilatation during Kyphoplasty.

Naturally, there are also other aspects that argue in favour of Vertebroplasty. For example, the much smaller external diameter of the Vertebroplasty needles which also allow the safer transpedicular access route in the upper part of the thoracic spine. To further minimise the risk of leakage, there is a tendency to apply smaller amounts of cement. In future this trend will also be reflected in the use of smaller needle diameters which make Vertebroplasty even more atraumatic for patients. Kyphoplasty cannot follow this trend due to design factors. The decision whether to perform the procedure under general or local anesthesia is ultimately taken by the physician based on an estimation of the patient’s situation. However, Kyphoplasty will more likely be performed under full sedation since it is a lengthier procedure due to the more elaborate instrumentation and therefore involves greater overall stress for the patient. A similar situation exists as regards radiation exposure for the physician and patient. The introduction and expansion of the balloon requires additional imaging and thus involves significantly higher radioexposure. This circumstance is of minor relevance for the patient. When all the treatments performed by a surgeon are taken together, however, they represent a markedly higher risk of physician exposure. Depending on the indication and the patient’s constitution, the advantages and disadvantages of the two procedures should be closely compared and weighed against each other. In all cases a decision should be made on an individualised basis, reflecting the patient’s intentions and with the patient’s benefit in mind.

Sincerely,

Thammo Weise