PubMed Health⌕ Search

Biomedical subjects

R D Bucholz

Publications and source records attributed to R D Bucholz.

35 records · Page 2Linked to original sources
PubMed1991

Transcranial Doppler ultrasound following closed head injury: vasospasm or vasoparalysis?

Nine patients suffering closed head injury were studied using transcranial Doppler ultrasound recording of the basal cerebral arteries. On admission, six patients had Glasgow Coma Scores of 7 or less, while three had initial scores of 8-10. Eight of the nine patients (82%) developed abnormally high mean velocities (greater than or equal to 110 cm/s) in one or more vessels. The onset, duration, and amplitude of the altered flow velocities were somewhat different from those that are seen with vasospasm after aneurysmal subarachnoid hemorrhage, which tend to occur later. Cerebral angiography in one of the study patients confirmed the presence of vasospasm. Multivariate regression analysis showed a definite correlation between the velocities recorded, even when abnormally elevated, and concurrent pH and PCO2 measurements (p = 0.01, R2 = 0.23). Although these results suggest that the cerebral vasculature retains its vasoreactivity following head injury, arguing against vasoparalysis, inconsistencies found in some of the patients lead us to think that both vasospasm and vasoparalysis may occur following head trauma but that they may have different temporal profiles.

Adolescent↗
PubMed1991

Open depressed skull fracture missed on computed tomography: a case report.

A case of an open depressed skull fracture that was missed on standard computed tomographic (CT) scan is presented. The fracture was seen on a CT generated lateral scout film, and after repositioning the gantry, further CT images clearly showed the fracture and underlying brain injury. The authors recommend that all patients with head trauma undergoing head CT have either a CT generated lateral scout film or a lateral skull radiograph to assess the vertex of the skull, an area poorly visualized on standard axial images.

Adult↗
PubMed1991

Endoscopic coagulation of the choroid plexus using the Nd:YAG laser: initial experience and proposal for management.

Although most patients with hydrocephalus are treated effectively with ventriculoperitoneal shunts, a small group fails to respond to diversion procedures. In some patients within this group, hydrocephalus may be caused in part by the overproduction of the cerebrospinal fluid (CSF). In other patients, previous shunt infections may limit the ability of the peritoneum to absorb fluid, and patient response to a ventriculoperitoneal shunt may be improved by reducing CSF production. We discuss a case of a 29-month-old hydrocephalic infant with a ventriculoperitoneal shunt who had ascites. Computed tomography showed bilateral symmetrical enlargement of the choroid plexus. Repeated cultures of the CSF and shunt tubing were sterile, and the daily production of the CSF exceeded 1000 ml. Therapy with acetazolamide decreased the CSF output temporarily, but it was discontinued after serious electrolyte abnormalities occurred. The endoscopic coagulation of the choroid plexus with a neodymium:YAG laser transmitted through a flexible quartz fiber decreased CSF production effectively. This procedure may be useful in a variety of clinical conditions associated with hydrocephalus or with other intraventricular lesions.

Child, Preschool↗
PubMed1990

Spinal cord arteriovenous malformation with an associated lymphatic anomaly. Case report.

Spinal cord arteriovenous malformations (AVM's), like other vascular anomalies of the central nervous system, can be associated with similar vascular lesions of the skin and viscera. A 7-year-old girl, who presented with rapidly progressing paraplegia, was found to have a spinal cord AVM, cutaneous angioma, and a chylous malformation of the lymphatic system. She had previously undergone treatment for a posterior thoracic cutaneous angioma. At surgery, upon incision of the paravertebral muscle fascia, viscous pale fluid was encountered emanating from a foramen in the thoracic lamina. The spinal AVM was resected in spite of concern that the abnormality represented spinal osteomyelitis. Postoperatively, there was full return of function in the lower extremities, along with recurrent episodes of chylothorax, which slowly came under control with dietary manipulation. A review of the anatomy of the thoracic duct and nontraumatic causes of chylothorax is presented, and the association of cutaneous and central angiomas is discussed. Finally, the treatment of chylothorax is delineated.

Arteriovenous Malformations↗
PubMed1989

Halo vest versus spinal fusion for cervical injury: evidence from an outcome study.

The indications for surgical fusion, as opposed to halo fixation, in the management of cervical spine injury are still unclear. At St. Louis University Medical Center a conservative protocol has been adopted to treat almost all cervical spine fractures with halo fixation. To determine what factors have contributed to failure of halo fixation, the records and radiographs of all patients with cervical spine injuries who were treated at that institution between 1984 and 1986 were reviewed. During this interval, 124 patients were treated, consisting of 93 men and 31 women between 6 and 94 years old. Of these, 15 (12%) had cervical fusion without preoperative halo device application. This group included eight patients with old injuries and delayed diagnosis, three with nonreducible locked facets, and four with miscellaneous indications. The remaining 109 patients were treated with halo vests. Four died before completing the 3-month standard treatment. Of those completing the treatment, 48 had C1-2 level injuries and 57 had C3-T1 level injuries. Sixteen patients (15%) failed their halo treatments and required surgical fusion: eight while still in halo fixation and eight after they had completed treatment with a halo device. Failure of halo treatment was indicated by recurrent dislocation in 13 patients and increased neurological deficit in three. Thirteen of the patients who failed treatment had C3-T1 injuries and three had C1-2 injuries. Of 27 patients with odontoid fractures, only two (7.4%) failed halo fixation. There were no failures in 11 patients with hangman's fractures. Of the 57 patients with C3-T1 injuries, 13 (23%) failed treatment, nine of whom had locked or "perched" facets. The factors causing failure of halo fixation were analyzed. The overall success rate was 85%, suggesting that the halo vest can be used to treat most patients with cervical spine injuries. Under certain circumstances (in the presence of old injuries, difficult reduction, or locked or "perched" facets), surgery may be indicated to avoid unnecessary delay in definitive management.

Adolescent↗
PubMed1987

Temporoparietal craniopagus. Case report and review of the literature.

A case of craniopagus twins joined in the temporoparietal area is presented, along with a review of the literature on craniopagus. A large area of brain was shared between the neurologically normal infants, with defects in the scalp, skull, and dura. The twins were separated in a three-step procedure. First, areas of shared brain were divided and separated with silicone sheets. The second procedure consisted of the insertion of scalp expanders to allow primary skin closure. In the third procedure complete separation was performed which was complicated by severe hypotension in one infant that was due to dural sinus hemorrhage. Cerebrospinal fluid leak was the most difficult problem encountered in the postoperative period; this was treated with lumboperitoneal and ventriculoperitoneal shunts. After 2 years, one twin is neurologically normal; the other is severely developmentally delayed, possibly related to the severe hypotension experienced during the third procedure. A review of the literature on craniopagus is presented. Analysis of data in the literature suggests that the area involved in the craniopagus as well as the venous connections are closely related to survival following separation of craniopagus twins.

Brain↗
PubMed1985

Separation of craniopagus twins utilizing tissue expanders.

An example of craniopagus Siamese twins is presented. The methods used in their separation using skin expanders and scalp flaps to achieve primary closure of the wounds with hair-bearing scalp are outlined. A detailed discussion of the planning and the mathematical considerations of these skin expanders and scalp flaps is included.

Brain↗
PubMedDate not supplied

Frameless stereotactic ultrasonography: method and applications.

In stereotactic neurosurgery, computed tomography (CT) and magnetic resonance (MR) images are registered in a coordinate system defined with respect to the skull. By intraoperatively tracking the coordinate position of a surgical instrument, various displays can be formed which show the position of the instrument in the MR and/or CT images. However, the accuracy of this display varies because intracranial structures may shift or warp from their position prior to surgery. Ultrasonic imaging systems provide real-time images of the brain, but structures in these images are difficult to interpret because the images are based on ultrasonic echoes. A method has been developed for the real-time registration of these images. With this registration, software continuously updates a corresponding image constructed from the set of MR and/or CT images used for guidance. By developing this second view of the structures in the ultrasound image, the surgeon can easily interpret the ultrasound image, and it becomes possible to determine the extent of the intra-operative structure shift between the two images.

Algorithms↗
PubMedDate not supplied

The NeuroStation--a highly accurate, minimally invasive solution to frameless stereotactic neurosurgery.

The NeuroStation is an image-guided neurosurgery workstation designed to deliver frameless stereotaxy within an ergonomic, integrated surgical environment. Generally, stereotaxy can provide the neurosurgeon with important intra-operative localization information using diagnostic images such as computerized tomography (CT) or magnetic resonance imaging (MRI). To date, however, stereotaxy has not been widely accepted by neurosurgeons due to the procedural difficulties of incorporating conventional stereotaxy. The NeuroStation addresses the problems of conventional stereotaxy through the use of frameless stereotactic methods wherein state-of-the-art instrumentation and computer innovations allow: a) standard surgical instruments to be used as the localization device; b) multipoint registration methods in place of frame-based registration; and c) real-time interactive surgical localization. The NeuroStation can thus be transparently integrated into the neurosurgical procedure providing the neurosurgeon with image-guidance for surgical planning, biopsies, craniotomies, endoscopy, intra-operative ultrasound, radiation therapy, etc.

Adult↗
PubMedDate not supplied

An accurate and ergonomic method of registration for image-guided neurosurgery.

We have developed a system for accurately and conveniently achieving surgical registration for image-guided neurosurgery, based on alignment and matching of patient forehead contours. The system consists of a contour digitizer that is used in the operating room to acquire patient contours, editing software for extracting contours from patient image data sets, and a contour-match algorithm for aligning the two contours and performing data set registration. Initial tests of the individual portions of the system have found each to be robust; we are in the process of refining the design of the optical digitizer in order to further automate the procedure as well as provide increased accuracy.

Algorithms↗
PubMedDate not supplied

Post-traumatic spinal synovial cyst with spondylolysis: CT features.

A spinal synovial cyst at L2-L3 produced obstruction at myelography and simulated an intraspinal tumor on CT. The CT recognition of bilateral spondylolysis of L3 suggested the possibility of a mobile posterior arch of L3 and associated synovial herniation. This was verified at surgery.

Adult↗
PubMedDate not supplied

MR imaging of lumbar juxtaarticular cysts.

Three surgically proven cases of lumbar extradural juxtaarticular cysts were examined by magnetic resonance (MR) imaging. The highly variable MR signal patterns are presented.

Adult↗
PubMedDate not supplied

Acellular dermal allograft for sellar reconstruction after transsphenoidal hypophysectomy.

Obliteration of the sphenoid sinus using fat is often used after transsphenoidal hypophysectomy. The morbidity of this approach includes donor site complications, fat necrosis, and delayed mucocele formation. As obliteration with fat is intended to prevent cerebrospinal fluid (CSF) leakage, an alternative for this technique would be techniques used for CSF rhinorrhea repair. Instead of sinus obliteration, these defects are repaired with fascial autografts, which are unfortunately associated with donor site complications. To avoid sinus obliteration and donor site complications, we have reconstructed the sella with acellular dermal allograft in lieu of sinus obliteration. Transsphenoidal hypophysectomy was performed under combined microscopic and endoscopic visualization. For closure, the sellar anterior wall was reconstructed with acellular dermal allograft, septal cartilage/bone autograft, and fibrin glue. The sinus mucosa was then draped over the reconstruction and held in place with microfibrillar collagen hemostat slurry. The sphenoid sinus was not obliterated. Postoperatively, all patients underwent serial nasal endoscopy. Thirteen patients underwent the procedure as described for removal of pituitary adenoma. Postoperative discomfort and pain were minimal. Intraoperative CSF leaks were identified in five patients; none of these patients experienced a postoperative CSF leak. The microfibrillar collagen hemostat was cleared by sphenoid mucociliary clearance. One patient developed acute sphenoid sinusitis several weeks after surgery; this patient did not develop meningitis. One postoperative CSF leak occurred in an obese patient, in whom an intraoperative CSF leak was not identified; this leak resolved with bedrest and delayed lumbar drainage alone. Sellar reconstruction with acellular dermal allograft may eliminate the need for sphenoid sinus obliteration after transsphenoidal hypophysectomy. Acellular dermal allograft sellar reconstruction ultimately provides for an aerated, functioning sphenoid sinus without increased CSF leak risk or potential donor site morbidity.

Female↗
PubMedDate not supplied

Triple-technique (MR imaging, single-photon emission CT, and CT) coregistration for image-guided surgical evaluation of patients with intractable epilepsy.

Ictal and interictal single-photon emission CT (SPECT) play an increasingly important role in the surgical evaluation of patients with epilepsy. We present a method of coregistration of MR, SPECT, and CT images to correlate structural data (MR imaging), blood flow changes (SPECT), and location of subdural electrodes (CT) for patients undergoing image-guided surgical treatment of epilepsy. MR-SPECT root mean square (rms) mismatch distances were 2.1 to 2.5 mm, and MR-CT rms mismatch distances were 1.0 to 4.5 mm. Coregistration assisted in image-guided placement of subdural electrodes and in surgical resection of the suspected epileptogenic focus.

Adolescent↗
PubMedDate not supplied

Predictive value of hippocampal MR imaging-based high-dimensional mapping in mesial temporal epilepsy: preliminary findings.

BACKGROUND AND PURPOSE: We objectively assessed surface structural changes of the hippocampus in mesial temporal sclerosis (MTS) and assessed the ability of large-deformation high-dimensional mapping (HDM-LD) to demonstrate hippocampal surface symmetry and predict group classification of MTS in right and left MTS groups compared with control subjects. METHODS: Using eigenvector field analysis of HDM-LD segmentations of the hippocampus, we compared the symmetry of changes in the right and left MTS groups with a group of 15 matched controls. To assess the ability of HDM-LD to predict group classification, eigenvectors were selected by a logistic regression procedure when comparing the MTS group with control subjects. RESULTS: Multivariate analysis of variance on the coefficients from the first 9 eigenvectors accounted for 75% of the total variance between groups. The first 3 eigenvectors showed the largest differences between the control group and each of the MTS groups, but with eigenvector 2 showing the greatest difference in the MTS groups. Reconstruction of the hippocampal deformation vector fields due solely to eigenvector 2 shows symmetrical patterns in the right and left MTS groups. A "leave-one-out" (jackknife) procedure correctly predicted group classification in 14 of 15 (93.3%) left MTS subjects and all 15 right MTS subjects. CONCLUSION: Analysis of principal dimensions of hippocampal shape change suggests that MTS, after accounting for normal right-left asymmetries, affects the right and left hippocampal surface structure very symmetrically. Preliminary analysis using HDM-LD shows it can predict group classification of MTS and control hippocampi in this well-defined population of patients with MTS and mesial temporal lobe epilepsy (MTLE).

Adult↗