Percutaneous vertebral compression fracture management with polyethylene mesh-contained morcelized allograft bone

Percutaneous vertebral augmentation with polyethylene mesh and allograft bone for traumatic thoracolumbar fractures

Purpose. In cases of traumatic thoracolumbar fractures, percutaneous vertebral augmentation can be used in addition to posterior stabilisation. The use of an augmentation technique with a bone-filled polyethylene mesh as a stand-alone treatment for traumatic vertebral fractures has not yet been investigated. Methods. In this retrospective study, 17 patients with acute type A3.1 fractures of the thoracic or lumbar spine underwent stand-alone augmentation with mesh and allograft bone and were followed up for one year using pain scales and sagittal endplate angles. Results. From before surgery to 12 months after surgery, pain and physical function improved significantly, as indicated by an improvement in the median VAS score and in the median pain and work scale scores. From before to immediately after surgery, all patients showed a significant improvement in mean mono- and bisegmental kyphoses. During the one-year period, there was a significant loss of correction. Conclusions. Based on this data a stand-alone approach with vertebral augmentation with polyethylene mesh and allograft bone is not a suitable therapy option for incomplete burst fractures for a young patient collective.

Macromolecule extravasation-xenograft size matters: a systematic study using probe-based confocal laser endomicroscopy (pCLE)

PURPOSE

Profound changes of the vasculature in tumors critically impact drug delivery and therapy response. We aimed at developing a procedure to monitor morphological and functional parameters of the vasculature in subcutaneous xenograft models commonly applied for therapy testing by using probe-based confocal laser endomicroscopy.

PROCEDURES

By monitoring various normal and diseased tissues, we established an experimental and analytical set-up to systematically analyze tracer extravasation from the microvasculature. Application of the approach in two xenograft models (HCT-116 and SW620) was realized consecutively throughout tumor growth.

RESULTS

The incidence of dilated vessels increased with xenograft size in both models while macromolecule extravasation and tracer accumulation in the tumor tissue, respectively, was significantly reduced throughout growth. The development of dilated/ultradilated vessels correlated with tracer extravasation only in the HCT-116 but not the SW620 model. The underlying mechanisms are still ambiguous and discussed.

CONCLUSIONS

Our findings clearly indicate that both xenograft type and size matter for drug delivery and therapy testing.

Real-time assessment of ultrasound-mediated drug delivery using fibered confocal fluorescence microscopy

PURPOSE

Transport across the plasma membrane is a critical step of drug delivery for weakly permeable compounds with intracellular mode of action. The purpose of this study is to demonstrate real-time monitoring of ultrasound (US)-mediated cell-impermeable model drug uptake with fibered confocal fluorescence microscopy (FCFM).

PROCEDURES

An in vitro setup was designed to combine a mono-element US transducer, a cell chamber with a monolayer of tumor cells together with SonoVue microbubbles, and a FCFM system. The cell-impermeable intercalating dye, SYTOX Green, was used to monitor US-mediated uptake.

RESULTS

The majority of the cell population showed fluorescence signal enhancement 10 s after US onset. The mean rate constant k of signal enhancement was calculated to be 0.23 ± 0.04 min(-1).

CONCLUSIONS

Feasibility of real-time monitoring of US-mediated intracellular delivery by FCFM has been demonstrated. The method allowed quantitative assessment of model drug uptake, holding great promise for further local drug delivery studies.

Multiphoton microscopy and microspectroscopy for diagnostics of inflammatory and neoplastic lung

Limitations of current medical procedures for detecting early lung cancers inspire the need for new diagnostic imaging modalities for the direct microscopic visualization of lung nodules. Multiphoton microscopy (MPM) provides for subcellular resolution imaging of intrinsic fluorescence from unprocessed tissue with minimal optical attenuation and photodamage. We demonstrate that MPM detects morphological and spectral features of lung tissue and differentiates between normal, inflammatory and neoplastic lung. Ex vivo MPM imaging of intrinsic two-photon excited fluorescence was performed on mouse and canine neoplastic, inflammatory and tumor-free lung sites. Results showed that MPM detected microanatomical differences between tumor-free and neoplastic lung tissue similar to standard histopathology but without the need for tissue processing. Furthermore, inflammatory sites displayed a distinct red-shifted fluorescence compared to neoplasms in both mouse and canine lung, and adenocarcinomas displayed a less pronounced fluorescence emission in the 500 to 550 nm region compared to adenomas in mouse models of lung cancer. These spectral distinctions were also confirmed by two-photon excited fluorescence microspectroscopy. We demonstrate the feasibility of applying MPM imaging of intrinsic fluorescence for the differentiation of lung neoplasms, inflammatory and tumor-free lung, which motivates the application of multiphoton endoscopy for the in situ imaging of lung nodules.

Treatment of an osteoporotic vertebral compression fracture with the StaXx FX system resulting in intrathoracic wafers: a serious complication

Purpose

To report a serious complication of the StaXx FX system used to stabilize an osteoporotic vertebral fracture.

Case report

A 76-year-old woman presented with a painful vertebral fracture. Treatment by means of a PEEK wafer kyphoplasty was complicated by malposition of the wafers. The patient recovered fully after removal of the wafers by means of a thoracotomy.

Conclusions

New treatment modalities have their own pitfalls and possible complications, as demonstrated in this case report. Caution regarding implementation of new treatment modalities should be practiced.

The biomechanical effects of osteoporosis vertebral augmentation with cancellous bone granules or bone cement on treated and adjacent non-treated vertebral bodies: a finite element evaluation

BACKGROUND

In order to reduce the complications of bone cement, many efforts are underway to replace bone cement augmentation with cancellous bone granule augmentation for treating compression fractures of osteoporotic vertebral bodies. The goal of this study was to investigate the biomechanical effects of cancellous bone granule augmentation of Optimesh and polymethylmethacrylate augmentation of kyphoplasty on treated and adjacent non-treated vertebral bodies.

METHODS

Three-dimensional, anatomically detailed finite element models of the L1-L2 functional spinal unit were developed on the basis of cadaver computed tomography scans. The material properties and plug forms of the L2 centrum were adapted to simulate osteoporosis, cancellous bone granule and polymethylmethacrylate augmentation. The models assumed a three-column loading configuration as the following types: compression, flexion and extension.

FINDINGS

Compared with the osteoporotic model, changes in stress and strain at adjacent levels both of cancellous bone granule and polymethylmethacrylate augmentation models were minimal, but stresses/strains within the two reinforcement material plugs were modified distinctly and differently. In addition, osteoporosis and augmentation had little effect on either the axial compressive displacement of the three columns or the average disc internal pressure in all models.

INTERPRETATION

Both cancellous bone granule and polymethylmethacrylate augmentation restore the total strength and stiffness level of treated vertebral bodies and benefit the reconstruction of vertebral function. Regarding the material mechanical compatibility and the biocompatibility of the treated vertebral body and reinforcement material, however, the morcelized cancellous bone is better than polymethylmethacrylate augmentation.