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Biomedical subjects

W Rauschning

Publications and source records attributed to W Rauschning.

At least 37 records · Page 2Linked to original sources
PubMed1992

Vertebral burst fractures: an experimental, morphologic, and radiographic study.

Spinal burst fractures are produced by rapid compressive loading, and may result in spinal cord injury from bone fragments forced from the vertebral body into the spinal canal. This fracture is one of the most difficult injuries of the spine to successfully treat, in part because the biomechanics of reduction and the exact mechanism by which the distraction forces are transmitted to the intracanal fragments of the burst fracture have not been adequately investigated. The authors developed a reproducible technique for creating these fractures in vitro. The fractures produced were identical to those observed in clinical practice, and were used for investigating the mechanics of this fracture and its reduction. This work describes the pathologic anatomy of the burst fracture both on the gross structure and also on microtome sections of the vertebrae, and examines the biomechanics of fracture reduction. The margins of the vertebral bone fragment, which was forced posteriorly into the spinal canal during fracture, were noted to extend far laterally beyond the pedicles. The authors also found extensive damage not only to the disc above the injured level, but also to that below, explaining the clinical observation that disc degeneration frequently occurs at both levels. Examination of anatomic data provided by microtome section supported the hypothesis that the fibers that actually reduce the intracanal fragment originate in the anulus of the superior vertebra in the midportion of the endplate and insert into the lateral margins of the intracanal fragment. Investigations using magnetic resonance imaging confirmed that these obliquely directed fibers account for the indirect reduction of the fragment. The authors' studies demonstrate that the posterior longitudinal ligament provides only a minor contribution in the reduction of the fracture in comparison to the attachments of the posterior portion of the anulus fibrosus. The forces required to reduce this fragment were studied. Distraction was found to be the predominant force required for indirect posterior reduction. This was confirmed by a series of tests using devices that provided segmental fixation. The application of uniform distraction forces was most effective in the posterior reduction of the intracanal fragment.

Adult↗
PubMed1992

Anatomic and technical considerations of pedicle screw fixation.

Pedicle screw systems provide significant and, in many cases, improved and previously unattainable spinal fixation. However, pedicle screw systems represent difficult surgical techniques involving several potential problems and complications. Only by detailed knowledge of the anatomy of the spine, with a clear understanding of the pedicle screw systems implementation, can the risks of complications be minimized.

Blood Vessels↗
PubMed1992

Postoperative cervical spine specimens studied with the cryoplaning technique.

Eight cervical spine specimens from patients who had undergone anterior and/or posterior screwplate fixation for traumatic or pathologic fractures and degenerative disorders were frozen in situ during clinical autopsies after the arteries were injected with red contrast medium. After partial thawing of the specimens, the metallic implants were extracted and the screw tracts and other implant cavities were filled with blue casting medium. Sagittal high-resolution computed tomography (CT) scans of the frozen specimens were obtained and correlated with closely spaced cryosectional images at the same levels. This technique not only facilitates accurate radiologic pathoanatomic correlations, but also detailed analysis of implant positioning, adequacy of reduction and decompression, and the cause of surgical complications.

Aged↗
PubMed1992

MR imaging with histopathological correlation in vertebral metastases of breast cancer.

In 5 patients with advanced breast cancer and spinal metastases MR imaging of the spine was performed before and/or after death. T1-, proton density-, and T2-weighted and "phase contrast" images were obtained in the sagittal plane. Autopsies included histopathologic examination of whole sagittal sections of the vertebral body. The relative signal intensities on the different MR sequences of various tissues identified histologically were evaluated. "Phase contrast" images combined with T1-weighted images were highly sensitive in detecting metastases. All metastatic tumours over 3 mm in size were found with MR imaging. Vertebrae containing connective tissue and reactive bone marrow had an MR appearance similar to that of metastases even though no metastases were found histopathologically.

Adult↗
PubMed1992

Epicardial fat causing pitfalls in CT and MR imaging of the pericardium.

To study the complex anatomy of the pericardium and the pericardial recesses, notably the transverse sinus and the recess behind and under the common pulmonary artery, cryomicrotomy sections of 4 frozen cadaver specimens were correlated with CT and MR imaging in multiple planes. In addition, CT chest studies of 254 patients and MR chest studies from 78 patients were reviewed. Epicardial fat interposed between the transverse sinus of the pericardium and the ascending aorta was a normal finding confirmed by cryomicrotomy studies and seen by CT in 23 of 245 patients and in MR imaging in 3 of 78 patients. Epicardial fat indenting the pericardial sac below the common pulmonary artery caused an inhomogeneous signal, mimicking lymphadenopathy on coronal T1 weighted MR images in 4 patients.

Adipose Tissue↗
PubMed1991

Locking screw-plate fixation of cervical spine fractures with and without ancillary posterior plating.

Forty consecutive patients with 19 fractures and 21 fracture-dislocations in the lower cervical spine were treated prospectively with open reduction and interbody fusion, using the AO titanium locking screw-plate system. There were 30 men and 10 women with a mean age of 36 years (range 16-90 years). Eight were admitted tetraplegic, 12 tetraparetic, and 6 had nerve root injuries. Eleven of the fractures and 18 of the fracture-dislocations were also plated posteriorly. Complications included two cardiac arrests, two transient neurological impairments, two severe gastrointestinal bleedings, and one esophageal fistula. At 2-year follow-up, three patients had died and one had emigrated. Three out of ten patients who had complete motor loss initially had regained useful muscle function, while incomplete motor loss usually returned to normal. All fusions had healed in a good or acceptable position. Twenty-four of the 60 posterior plates impinged on facet joints and five were loose. Six screws transgressed facet joints below the fusion. Ten posterior fusions extended to adjacent mobile segments by exuberant bony overgrowth. Ancillary posterior plating significantly reduced the range of neck mobility and also caused significantly more pain than anterior plate fixation alone.

Adolescent↗
PubMed1991

Anatomy of the hip: correlation of coronal and sagittal cadaver cryomicrosections with magnetic resonance images.

Magnetic resonance imaging (MRI) is noninvasive and provides images with higher soft tissue contrast than possible with any other imaging modality. Unlike CT which depicts anatomy in the axial plane, MRI is capable of producing images in thin cross sections acquired directly in any plane, usually axial, coronal or sagittal planes. The use of diagnostic MR images is facilitated by an understanding of the detailed anatomy that is depicted. The purpose of this study was to identify anatomical structures in coronal and sagittal cryomicrosections of the hip region. Thin cryosections of the hips of fresh-frozen cadavers were obtained by a method developed by one of the authors (WR). These sections were matched with thin-section, high resolution MR images of a normal volunteer. The complex anatomy of the hip and its surrounding muscles, tendons and ligaments was exquisitely depicted on both the cadaver microcryosections and the matched MRT images.

Cadaver↗
PubMed1991

Hidden cervical spine injuries in traffic accident victims with skull fractures.

We studied 22 cervical spines from traffic accident victims with fatal craniocerebral injuries (19 male victims and three female victims; mean age, 26 years). Two had parietal fractures, 20 had skull base fractures (seven ring fractures), and 16 had severe polytrauma. The spines with all soft tissues were frozen in situ and removed. Fine-focus specimen radiograms were taken in special views and evaluated by an expert orthopedic radiologist. The specimens were then cryosectioned, and all injuries were recorded at submillimeter intervals on high resolution film. Ten radiological fracture diagnoses were incorrect; six were false positive, and four were false negative. In the upper cervical spine, only one of 10 gross ligamentous disruptions was suspected on the radiograms. In the lower cervical spine, 198 lesions were missed on the radiograms: 77 facet joint and ligamentum flavum injuries, 77 uncovertebral, and 22 disc lesions. In two adolescents, eight cartilaginous end-plate avulsions of the discs were found. At second-look evaluation, only four of the 245 unrecognized bone and discoligamentous lesions were detected on the radiograms. All spines were injured. Multiple-level soft-tissue injuries were common.

Accidents, Traffic↗
PubMed1991

Surgical anatomy of the sacrum. A guide for rational screw fixation.

Anterior sacral anatomy was studied to allow safe sacral screw placement. The study included 27 bony sacra. Intrapelvic dissections were performed. Cadaveric specimens were dissected and photographed. The position and angulation of the first sacral foramen was extremely variable. After the position of the L5 root, sacral roots, and iliac vessels, was considered, safe posterior sacral screw implantation could be assured through placement above the level of the first sacral foramen directed medially toward the promontory, parallel to the superior sacral end-plate. Complications of indiscriminate screw placement included L5-root damage, iliac vein penetration, and intractable perineal pain due to sacral root injury. Preoperative computed tomography with the scanner gantry tilted to parallel the superior sacral end-plate defined the great vessels, neural foramens, inclination of the superior sacral end-plate, and prominence of the posterior ileum. Surgical accuracy was evaluated after surgery with computed tomography.

Bone Screws↗
PubMed1991

Anatomic and biomechanical assessment of transarticular screw fixation for atlantoaxial instability.

The purpose of this study is to elucidate anatomically the atlantoaxial transarticular screw fixation described by Magerl in 1979 and compare it biomechanically with Gallie wiring. Five human C1-C2 specimens were tested in flexion/extension and rotation intact, then after wiring and screw fixation. Mean screw length was 39 mm, 25 mm in the C2 lamina and 14 mm in the lateral mass. Angular displacement of screwed specimens was significantly less than control or wired groups. Stiffness at 0-0.5 Nm loads was significantly greater for screwed specimens than for wired or controls (101 +/- 49 Nm, 10.3 +/- 9.2 Nm, and 1.96 +/- 0.18 Nm, respectively). All specimens withstood 5 Nm in flexion and extension without failure. Screw fixation provides stability comparable to Gallie wiring and is stiffer at low-range forces and rotational angles.

Atlanto-Axial Joint↗
PubMed1990

An evaluation of spinal deformity in metastatic breast cancer.

Between October 1984 and January 1988 31 magnetic resonance (MR) imaging studies were performed on 27 patients with metastatic vertebral breast cancer (MVBC). The MR images were reviewed to determine the extent and type of sagittal spinal deformity, and whether spinal canal compromise was present. Adjunct studies were compared to determine the pathogenesis of spinal deformity and the etiology of spinal canal compromise. An analysis of the data revealed that a consistent pattern of sagittal spinal deformity exists with MVBC, and a classification system was developed to describe the stages of vertebral deformity. Criteria are suggested for identifying metastatic spinal instability. A protocol is presented for treating patients with metastatic spinal involvement. By understanding the natural history of metastatic spinal deformity, instability and spinal canal compromise can be recognized and treated early, before the onset of progressive deformity and neurologic sequelae.

Breast Neoplasms↗
PubMed1989

Carboplatin. The better platinum in head and neck cancer?

Chemotherapeutic regimens containing cisplatin are the most effective ones in the treatment of squamous cell carcinoma of the head and neck. Because of the high rate of dose-limiting side effects of cisplatin, carboplatin, a second-generation cisplatin analogue, was tested in a phase II trial with fluorouracil in 55 previously untreated patients with advanced carcinoma of the head and neck. Among the 52 patients who completed the study, there were 17 complete responses (33%), 28 partial responses (54%), five patients with no change (10%), and two with progressive disease (4%). Toxic side effects of all courses summed together included leukopenia in 65% of courses, thrombocytopenia in 45% of courses, nausea or vomiting in 29% of courses, and change in serum creatinine level in 3% of courses. These data were compared with the results of our study with cisplatin and fluorouracil in comparable patients and indicated that carboplatin and fluorouracil is better for induction chemotherapy in the treatment of head and neck cancer than cisplatin and fluorouracil due to similar effectiveness but less toxic effect.

Antineoplastic Agents↗
PubMed1989

Phase II study with etoposide in previously untreated advanced breast cancer.

A phase II study was carried out to evaluate the efficacy and safety of etoposide used as first-line chemotherapy for patients with advanced breast carcinoma. A total of 20 patients received 230 mg/m2 i.v. etoposide per day for 3 days (total, 690 mg/m2 per course) every 4 weeks. A total of 95 courses were given. Observed responses included 3 partial remissions (PR) and 14 cases of stable disease (NC). The median duration of response was 6 (PR) and 5.6 months (NC). Contrary to the severe hematological toxicity in heavily pretreated patients described in previous studies, no substantial problems were observed in this trial. No dose reduction was necessary, and only once did leukopenia lead to a 1-week delay in therapy. An increase in platelets up to a maximum of 685,000/mm3 was seen in all patients, particularly in those with bone metastases. No relation to the quality of remission or pretreatment was seen. Nausea, vomiting, and fatique were mild and transient, but alopecia occurred in all cases. One patient developed nonfatal anaphylactic shock after etoposide treatment.

Adult↗
PubMed1989

Pathoanatomical and surgical findings in cervical spinal injuries.

The pathomorphology of normal and degenerated human cervical spines that had been subjected to trauma was studied in detail by surface-cryoplaning of frozen autopsy specimens. Four cervical spines that had been surgically fused were also sectioned after removal of the metal. In young individuals, disc ruptures occurred that resulted in compromise of the vertebral canal. In degenerated spines, vertebral endplate ridges were frequently fractured. These injuries resulted in encroachment on the spinal cord as well as on the nerve roots in the foramen. Osteophytes from the uncinate processes also contributed to stenosis at the nerve root exist. These pathoanatomical findings were corroborated by intraoperative observations in patients. The high incidence of compressive lesions anteriorly in the cervical spine underscores the need to consider both anterior and posterior surgery in many of these patients.

Adult↗
PubMed1988

Lateral lumbar spinal canal stenosis: classification, pathologic anatomy and surgical decompression.

The lateral region of the lumbar spinal canal is subject to pathologic alterations which encroach upon the neural structures located within. In order to further understanding and facilitate communication among specialists in diverse disciplines, a subdivision of the lateral region is proposed to comprise three zones: entrance zone, mid-zone and exit zone. The anatomical boundaries of these zones are defined and the pathologic conditions of each are described, and serve as the basis for techniques of surgical decompression when clinically required.

Humans↗
PubMed1988

Three-dimensional movements of the upper cervical spine.

Knowledge of the normal movements of the occipito-atlanto-axial joint complex is important for evaluating clinical cases that may be potentially unstable. The purpose of this in vitro study was to quantitatively determine three dimensional movements of the occiput-C1 and C1-C2 joints. Ten fresh cadaveric whole cervical spine specimens (occiput to C7) were studied, using well-established techniques to document the movements in flexion, extension, left and right lateral bending, and left and right axial rotation. Pure moments of a maximum of 1.5 N-m were applied incrementally, and three-dimensional movements of the bones were recorded using stereophotogrammetry. Each moment was applied individually and in three load/unload cycles. The motion measurements were made on the third load cycle. Parameters of neutral zone, elastic zone, and range of motion were computed. Neutral zones for flexion/extension, right/left lateral bending, and right/left axial rotation were, respectively: 1.1, 1.5, and 1.6 (occiput-C1); and 3.2, 1.2, and 29.6 degrees (C1-C2). Ranges of motion for flexion, extension, lateral bending (one side), and axial rotation (one side) were, respectively: 3.5, 21.0, 5.5, and 7.2 degrees (occiput-C1 joint) and 11.5, 10.9, 6.7, and 38.9 degrees (C1-C2 joint). The greatest intervertebral motion in the spine was axial rotation at the C1-C2 joint, with the neutral zone constituting 75% of this motion.

Adult↗