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Biomedical subjects

A Gevargez

Publications and source records attributed to A Gevargez.

6 recordsLinked to original sources
PubMed2000

CT-guided percutaneous laser disc decompression with Ceralas D, a diode laser with 980-nm wavelength and 200-microm fiber optics.

The aim of this study was to evaluate the compact, portable Ceralas-D diode laser (CeramOptec; 980 + 30 nm wavelength, 200-microm optical fiber) concerning clinical usefulness, handling, and clinical results in the CT-guided treatment of herniated lumbar discs. The positioning of the canula in intradiscal space, the placement of the laser fiber into the disc through the lying canula, and the vaporization itself were carried out under CT-guidance. Due to the thin fiber optic, it was possible to use a thin 23-gauge canula. The laser procedure was performed in 0.1- to 1-s shots with 1-s pulse pause and 4-W power output. A total of 1650-2300 J was applied on each percutaneous laser disc decompression (PLDD). Results in 26 patients were established with a visual-analogue scale (VAS). On the follow-up examinations, 46% of the patients were absolutely pain free ( > 85 % VAS) and fully active in everyday life after 4 postoperative weeks. Thirty-one percent of patients were relieved of the leg pain but had occasional back pain without sensorimotor impairment. Fifteen percent sensed a slight alleviation ( > 50% VAS) of the radiate pain. Eight percent did not experience radicular or pseudo-radicular pain alleviation (< 25% VAS). Cerales-D proves to be an efficient tool for CT-guided PLDD on non-sequestered herniated lumbar discs.

Adult↗
PubMed2000

[Precision and comparison of CT-, MRI- and DL-controlled interventions exemplified by lumbar facet infiltration--an experimental study].

We evaluated the accuracy of the needle tip representation by different imaging techniques for the guidance of facet infiltrations. For visualisation of the lumbar facet joints we used a high-field magnetic resonance tomograph (MRT) with a 2.0 Tesla field and 3.5 mm slice thickness, an open low-field magnetic resonance tomography (MRT) with an 0.064 Tesla field and 9 mm slice thickness, and IMATRON electron beam computed tomograph (EBCT) with a slice thickness of 6 mm, and a mobile C-arm fluoroscope. The study was performed on 4 human cadaveric lumber spine preparations, each of which had 8 facet joints. Under imaging control, special injection needles were placed as close as possible to the facet joint space. Following placement of he needle, all specimens were scanned with the electron beam tomograph using a slice thickness of 1.5 mm. The thin-slice study served as the gold standard. The distance between the tip of the needle and the facet joint was measured in all the images. Comparison of the different modalities with the gold standard revealed the following results: 1) median values of the absolute differences were 1.25 mm for high-field MRI, 1.35 mm for 6 mm EBCT, 2.05 mm for low-field MRI, and 2.30 mm for X-ray fluoroscopy. 2) While there was no statistically significant difference in the accuracy of tip localization between high-field MRI and 6" EBCT (p = 0.293), both systems were more precise than low-field MRI (p = 0.04) and X-ray fluoroscopy (p = 0.009). When choosing the best imaging technique, such additional factors as radiation, costs and time, must also be considered. Provided necessary radiological precautions are taken, and assuming careful pre-interventional planning, CT. EBCT and X-ray fluoroscopy are currently more effective than the expensive, time-consuming and costly magnetic resonance tomography.

Equipment Design↗
PubMed1999

[Possibilities of spinal endoscopy within the scope of minimal invasive intervention--an experimental study].

The purpose of the present study was to evaluate, in vitro, a newly designed spinaloscope with a diameter of 1.8 mm, with integrated portals for instruments and irrigation. The 0 degree optical system has a resolution of 6,000 pixels. The instrument portals can be used for surgical lasers, biopsy forceps or burrs. We carried out our evaluations on fresh (unfixed) human lumbar spine specimens. The position of the endoscope was documented by CT scans. The endoscope was introduced into the spinal canal via the hiatus sacralis using a blunt trocar. The various structures and tissues were clearly identifiable and included the dura, the lig. flavum, the lig. long. posterior, spinal nerves, small pieces of disc material and various fibrous bands. The usefulness of the biopsy forceps was also shown.

Biopsy↗
PubMed1998

Tomographic microtherapy.

Minimally invasive techniques using endoscopes for image-guided therapy are now common in the field of surgery. Fast real-time radiologic imaging should be integrated into the procedure for increased safety in access and guidance techniques for endoscopes and instruments. The transparency of computed tomography (CT) guidance, magnetic resonance imaging, and electron beam tomography scan techniques allows precise guidance of instruments and endoscopes while permitting their diameter to be minimized. This guarantees safe and transparent access into the body, especially in high-risk areas such as the spine and brain. Combining both technologies has the potential to reduce complications and offers significant advantages in microinvasive operative procedures such as biopsies; local tumor therapy with lasers, radio frequency, or drugs; and percutaneous diskectomies or implants. CT is the golden standard for microtherapeutic procedures because of its precise tip discrimination.

Diagnostic Imaging↗
PubMedDate not supplied

[Percutaneous vertebral augmentation (PVA) in osteoporosis of the vertebrae--an experimental study].

The present study was conducted with the aim of establishing whether minimally invasive percutaneous techniques used to stabilize osteoporotic vertebrae are technically feasible. Two different methods were investigated in human thoracolumbar cadaveric vertebrae. In the first technique, special titanium implants were placed via a postero-lateral approach. With the second method, the vertebrae were filled with different types of cement of different viscosities. After each procedure, the vertebrae were examined with conventional X-ray and CT scans. The first technique proved quite unsuccessful--the insertion of the titanium implants proving difficult despite the use of special instruments. The results achieved with the second method were much better. The use of low-viscosity bone cement produced the best results. Despite a single lateral point of entry, the vertebrae were almost completely filled right into the contralateral side. Lumbar vertebrae required an average volume of cement of 7 ml (range: 6.5-10 ml) and thoracic vertebrae 5.5 ml (range: 4-7 ml). Specially developed cement application devices made possible problem-free, controlled introduction of the cement.

Aged↗