Zementaugmentation bei Wirbelmetastasen (Vertebro- und Kyphoplasie) [Cement injection for spinal metastases (vertebroplasty and kyphoplasty)]

Osteolytic lesions of the spine (metastasis, myeloma) can be treated extremely efficiently by percutaneous cement injection. The treatment should be restricted to osteolytic lesions of the vertebral body, and only if a relevant mechanical deterioration is present. If the pedicles and/or the lamina are involved and if there is compression of the spinal canal, the treatment is no longer appropriate. The surgical technique is similar to the treatment of osteoporotic fractures; however, there is definitely a higher risk for cement leakage and the clinical outcome is not as predictable as in osteoporotic fracture treatment. It is important to realize that cement injection per se has no impact on the tumor itself, but provides stability to the vertebral body. An osteolytic lesion without mechanical compromise does not need a vertebroplasty. Patients with tumorous lesions of the spine should be followed by an interdisciplinary team of spine surgeon, oncologist and radio-oncologist.

Experimenter effects on behavioral test scores of eight inbred mouse strains under the influence of ethanol.

ight standard inbred mouse strains were evaluated for ethanol effects on a refined battery of behavioral tests in a study that was originally designed to assess the influence of rat odors in the colony on mouse behaviors. As part of the design of the study, two experimenters conducted the tests, and the study was carefully balanced so that equal numbers of mice in all groups and times of day were tested by each experimenter. A defect in airflow in the facility compromised the odor manipulation, and in fact the different odor exposure groups did not differ in their behaviors. The two experimenters, however, obtained markedly different results for three of the tests. Certain of the experimenter effects arose from the way they judged behaviors that were not automated and had to be rated by the experimenter, such as slips on the balance beam. Others were not evident prior to ethanol injection but had a major influence after the injection. For several measures, the experimenter effects were notably different for different inbred strains. Methods to evaluate and reduce the impact of experimenter effects in future research are discussed.

Percutaneous vertebroplasty, kyphoplasty and lordoplasty: implications for the anesthesiologist

PURPOSE OF REVIEW: Vertebroplasty, kyphoplasty and lordoplasty are minimally invasive procedures mainly performed for refractory pain due to osteoporotic vertebral body fractures. This review summarizes recent findings on outcome, complications and their impact on anesthetic management. RECENT FINDINGS: Despite an increasing number of publications on surgical technique, therapeutic efficacy and side effects of these interventions, anesthetic management per se is hardly investigated. All three treatments provide similar pain relief. Adverse effects include local cement leakage and new fractures adjacent to augmented vertebrae. Asymptomatic pulmonary cement embolism occurs in 4.6-6.8% of patients depending on cement viscosity, injection pressure and number of injected vertebrae. Potentially life-threatening embolism of cement or fat may occur. Kyphoplasty and lordoplasty aim at correcting vertebral deformity and are equally effective; lordoplasty is substantially less expensive, however. The incidence of systemic cement or fat embolism is similar to that in vertebroplasty. Whereas vertebroplasty is mostly performed under local anesthesia and sedation, general anesthesia is required for kyphoplasty and lordoplasty. The anesthetic regimen follows the principles of anesthesia in the elderly population. SUMMARY: Vertebroplasty, kyphoplasty and lordoplasty are effective minimally invasive treatments for stable vertebral compression fractures without compression of the spinal canal. The anesthesiologist must be prepared to manage systemic cement or fat embolism.

Percutaneous transluminal angioplasty and stent placement in acute vessel occlusion: evaluation of new methods for interventional stroke treatment

BACKGROUND AND PURPOSE: The major goal of acute ischemic stroke treatment is fast and sufficient recanalization. Percutaneous transluminal balloon angioplasty (PTA) and/or placement of a stent might achieve both by compressing the thrombus at the occlusion site. This study assesses the feasibility, recanalization rate, and complications of the 2 techniques in an animal model. MATERIALS AND METHODS: Thirty cranial vessels of 7 swine were occluded by injection of radiopaque thrombi. Fifteen vessel occlusions were treated by PTA alone and 15, by placement of a stent and postdilation. Recanalization was documented immediately after treatment and after 1, 2, and 3 hours. Thromboembolic events and dissections were documented. RESULTS: PTA was significantly faster to perform (mean, 16.6 minutes versus 33.0 minutes for stent placement; P < .001), but the mean recanalization rate after 1 hour was significantly better after stent placement compared with PTA alone (67.5% versus 14.6%, P < .001). Due to the self-expanding force of the stent, vessel diameter further increased with time, whereas the recanalization result after PTA was prone to reocclusion. Besides thromboembolic events related to the passing maneuvers at the occlusion site, no thrombus fragmentation and embolization occurred during balloon inflation or stent deployment. Flow to side branches could also be restored at the occlusion site because it was possible to direct thrombus compression. CONCLUSIONS: Stent placement and postdilation proved to be much more efficient in terms of acute and short-term vessel recanalization compared with PTA alone.

The effect of pulsed jet lavage in vertebroplasty on injection forces of PMMA bone cement: an animal study

Percutaneous vertebroplasty, comprising of the injection of polymethylmethacrylate (PMMA) into vertebral bodies, is an efficient procedure to stabilize osteoporotic compression fractures as well as other weakening lesions. Besides fat embolism, cement leakage is considered to be one of the major and most severe complications during percutaneous vertebroplasty. The viscosity of the PMMA during injection plays a key role in this context. It was shown in vitro that the best way to lower the risk of cement leakage is to inject the cement at higher viscosity, which is requires high injection forces. Injection forces can be reduced by applying a newly developed lavage technique as it was shown in vitro using human cadaver vertebrae. The purpose of this study was to prove the in vitro results in an in vivo model. The investigation was incorporated in an animal study that was performed to evaluate the cardiovascular reaction on cement augmentation using the lavage technique. Injection forces were measured with instrumentation for 1 cc syringes, additionally acquiring plunger displacement. Averaged injection forces measured, ranged from 12 to 130 N and from 28 to 140 N for the lavage group and the control group, respectively. Normalized injection forces (by viscosity and injection speed) showed a trend to be lower for the lavage group in comparison to the control group (P = 0.073). In conclusion, the clinical relevance on the investigated lavage technique concerning lowering injection forces was only shown by trend in the performed animal study. However, it might well be that the effect is more pronounced for osteoporotic vertebral bodies.

Percutaneous embolization of arteriovenous malformations at the plantar aspect of the foot

Peripheral arteriovenous malformations (AVM) remain most challenging among various congenital vascular malformations to be treated. Here we present three illustrative patients with Yakes type IIIb and type IV AVM at the plantar aspect of the foot who were successfully treated by minimally invasive embolization. The value of the Yakes AVM classification system to guide the therapeutic decision making by directing specific therapeutic procedures to specific AVM types defined by their angioarchitecture is demonstrated. Direct percutaneous AVM puncture with coiling of aneurysmal outflow vein and subsequent ethanol embolization is shown. Finally, the report illustrates that several AVM types can coexist.