PubMed Health⌕ Search

Biomedical subjects

D J Prolo

Publications and source records attributed to D J Prolo.

At least 19 recordsLinked to original sources
PubMed1991

The use of bone grafts and alloplastic materials in cranioplasty.

Trephination dates from prehistoric neolithic times (10,000-7000 B.C.) and is the oldest operation known. Cranioplasty with bone allografts dates from the Stone Age Celts. Through the millennia, generations of surgeons have tried bone autografts, allografts, and rarely xenografts for cranioplasty but abandoned these in favor of alloplastic metals and plastics, most recently methylmethacrylate. Disillusionment with bone cranioplasty has followed the recurrent experience that orthotopic transplantation of bone to skull is almost invariably accompanied by a striking propensity for resorption. Resorption coupled to new bone formation is the usual process of remodeling. A unique acellular nonosteoclastic resorption, antedating invasion of the graft by osteoprogenitor cells and unrelated to the remodeling, characterizes the initial response of bone placed in a skull bed. This previously undescribed resorption in the skull likely represents passive diffusion of mineral from an altered matrix (calciolysis) and varies directly with the degree the graft is denatured by processing. There is the least amount of resorption in the fresh autograft and the most in autoclaved or chemically treated frozen or freeze-dried grafts. Remodeling of this diminished template occurs centripetally from skull defect margins through osteoconductive mechanisms only. Marrow-poor skull with thin diploe provides few osteoprogenitor cells that slowly, incompletely remodel the reduced graft over years.

Biocompatible Materials↗
PubMed1990

Effects of stimulus intensity on direct recordings of eighth nerve auditory evoked responses.

Effects of auditory stimulus intensity on auditory nerve and brainstem evoked potential patterns recorded simultaneously from the scalp and directly from the eighth nerve were compared for an anesthetized patient undergoing surgery for macrovascular decompression. Replicable robust potentials were readily obtained from a recording electrode on the eighth nerve less than half a second after as few as 15 stimulations. Less robust and less readable evoked potential patterns were obtained from scalp recordings after 30 seconds and about 900 stimulations. It was observed in the direct auditory evoked response (DAER) that there is a systematic decrease in peak latencies with each 10 dB increase in stimulus intensity between 60 and 90 dB nHL. Also, with each 10 dB increase in stimulus intensity there is an increase in amplitude of the DAER action potential between 70 and 90 dB nHL but not between 60 and 70 dB.

Acoustic Stimulation↗
PubMed1986

Quantitative comparisons of healing in cranial fresh autografts, frozen autografts and processed autografts, and allografts in canine skull defects.

Adult dog skull defects larger than 17 mm do not spontaneously heal. A quest for a potentially viable, cosmetically, mechanically, and technically acceptable template for human cranial reconstruction prompted a comparison of processed autogeneic and allogeneic bone implants with a fresh autograft control in the dog. Quantitative reproducible observations demonstrated that fresh calvarial bone autografts were superior to the nonviable implants in volume percent defect filled, mm2 new cortical bone, mm2 new and old cortical bone, and cortical bone porosity. Frozen autografts achieved 75%, antigen-extracted, autolyzed, partially demineralized auto- and allografts, 50% of the overall efficiency of fresh autografts. Fresh cancellous bone added to allografts did not improve long-term repair. Remodeling of all grafts appeared consistent with osteoconductive invasion by peripheral host endosteal and diploic elements; host external periosteum and dura contributed less. Central osteoinductive recruitment of mesenchymal cells from muscle or dura seemed not to occur in the adult dog. Partially demineralized dog calvarial grafts were resorbed without acting as a template for new bone formation. Surface demineralization, antigen extraction, and autolytic digestion of autografts and allografts, with or without fresh iliac bone, did not improve calvarial bone regeneration in adult dogs.

Animals↗
PubMed1984

Clinical utility of allogeneic skull discs in human craniotomy.

One hundred fifteen burr hole defects were filled with sterilized human cadaver skull in 45 patients ranging in age between 10 and 88 years. One to 6 allogeneic skull discs per patient were placed in all areas of the calvaria. The length of postoperative observation ranges between 6 months and 5 years. No instances of infection, resorption, or rejection have occurred. Discs became incorporated and were osteoconductive, with new bone formed by "creeping substitution." In contrast to frozen autogeneic skull, these allogeneic discs were not resorbed. Allogeneic skull may be used safely and effectively to fill small discontinuity defects in the human calvaria.

Adolescent↗
PubMed1984

Composite autogeneic human cranioplasty: frozen skull supplemented with fresh iliac corticocancellous bone.

Skull totally exteriorized during craniotomy becomes nonviable. Resorption of the reimplanted cranial section occurs variably according to its treatment, the properties of the recipient bed, and the metabolic conditions of the host. Neurosurgeons commonly deep freeze autogeneic skull for preservation before delayed autogeneic cranioplasty. Aseptic necrosis commonly follows replacement of the autograft in its former cranial bed. This clinical study of six patients represents an attempt to block this destructive resorption by supplementing the frozen autograft with fresh corticocancellous autogeneic ilium. Observations of these patients ranging in age from 12 to 52 years support the following conclusions: (a) Osteogenesis was not enhanced by the addition of fresh corticocancellous bone to the frozen autoimplant. (b) The period of time that the autoimplant was frozen did not influence its subsequent biological behavior after cranioplasty. (c) Sterilization with ethylene oxide and in one case additional gamma irradiation did not impair the quality of the implant compared to those not sterilized. (d) Resorption occurred in both frozen and fresh but devitalized autogeneic skull. (e) Autogeneic skull is repaired by osteoconduction rather than by inducing competent perivascular stem cells to become osteogenic. (f) Freezing of autogeneic skull for preservation is practical, acceptable, but suboptimal from the perspectives of cerebral protection and cosmetic reconstruction. (g) The supplementation of the frozen autoimplant with fresh corticocancellous bone increases operating time and patient discomfort without affording additional benefit.

Adult↗
PubMed1983

Human bone morphogenetic protein (hBMP).

Human bone morphogenetic protein (hBMP) was chemically extracted from demineralized gelatinized cortical bone matrix by means of a CaCl2 X urea inorganic-organic solvent mixture, differential precipitation in guanidine hydrochloride, and preparative gel electrophoresis. hBMP is isolated in quantities of 1 mg/kg of wet weight of fresh bone, and has the amino-acid composition of an acidic polypeptide. The mol wt is 17 to 18 k-Da (kilodaltons). Implants of the isolated 17-kDa protein are very rapidly adsorbed and produce a smaller volume of bone than protein fractions consisting of 24-, 17-, and 14-kDa proteins. Since the isolated 24- and 14-kDA components lack hBMP activity, the kinetics of the bone morphogenetic processes including the function of other proteins as carrier molecules, await investigation.

Adult↗
PubMed1982

Superior osteogenesis in transplanted allogeneic canine skull following chemical sterilization.

Sterilization of allogeneic bone increases the availability of this tissue for supplanting skeletal defects and effecting fusions. The optimal sterilant destroys micro-organisms, preserves the physical and chemical integrity of bone and possibly even reduces immunogenicity. Cortical bone of skull heals slowly and is variably resorbed. Of 36 dogs, spontaneous regeneration in 72 paired 20 mm defects was constant but always incomplete, and restored only about one third of the cross-sectional area of the defect at six months. The repair in defects replaced with canine allogeneic bony disc, sterilized with ethylene oxide (n = 9), gamma irradiation (n = 7), or methanol/chloroform/iodoacetic acid (n = 7) and then lyophilizedd, was compared with repair in defects filled with aseptically procured lyophilized only (n = 23) discs from the same donor. Criteria for evaluation of implants at six months included volume of defect filled, radiodensity, extent of fusion around circumference, revascularization, and remodeling. Bony discs sterilized with methanol/chloroform/iodoacetic acid remodeled at a superior rate (p less than 0.01). Radiation sterilization resulted in diminished density and inferentially reduced protection of the brain (p less than 0.025). Ethylene oxide, lyophilized implants, and implants lyophilized only produced comparable repair. Whereas an acceptable cranioplasty was achieved in 86% of methanol/chloroform/iodoacetic acid, lyophilize implants, all other alloimplants served an osteoconductive function with a successful repair occurring in 56% to 58%.

Animals↗
PubMed1981

Balloon catheter occlusion for cavernous carotid artery injury during transsphenoidal hypophysectomy. Case report.

During transsphenoidal hypophysectomy for pituitary ablation in a patient with disseminated breast cancer, brisk arterial hemorrhage occurred during separation of adhesions between the pituitary gland and the wall of the cavernous sinus. Hemorrhage was controlled by placement of a Prolo balloon catheter into the internal carotid artery (ICA) that occluded the site of hemorrhage. The patient experienced no neurological sequelae. The cervical ICA was easily exposed for insertion of this double-lumen catheter. With the image intensifier already in position, injection of contrast material through the arteriography lumen allowed precise localization of the site of injury and directed positioning of the balloon for control of the hemorrhage.

Carotid Artery Injuries↗
PubMed1980

Ethylene oxide sterilization of bone, dura mater, and fascia lata for human transplantation.

The use of allogeneic human bone, dura, and fascia has achieved an enduring and accelerating role in the augmentation of spinal fusions and the repair of skeletal and dural defects. Primary sterilization of these nonviable cadaveric tissues magnifies the potential sources and ensures the microbiological sterility of the implant. Subsequent lyophilization facilitates preservation and distribution and reduces the immunogenicity of the graft. The evaluation of gaseous ethylene oxide (EO) as a sterilant was suggested by the delerious effects of alternative methods. Through a series of experiments, the following properties of EO sterilization were studied: (a) surface and interstitial sterilization; (b) the diffusion of EO into tissue, the formation of the reaction products ethylene chlorohydrin (EC) and ethylene glycol (EG), and the desorption of all three from tissues; (c) lyophilization and aeration in the removal of residues; and (d) minimization of residues through pretreatment. Gaseous EO is a very effective surface sterilant of wet bone, dura, and fascia and does not grossly alter these tissues. Its partial penetration through compact bone renders it less reliable for an interstitial antimicrobial effect, unless access to the interior is provided by serial openings. The toxicity of EO, EC, and EG mandates the desorption through lyophilization of these compounds (EC and EG are formed during sterilization with EO). Before sterilization, bone must be rid of marrow by vigorous irrigation with deionized water. The resultant reduction of the number of cells and of the available chloride decreases antigenicity and the formation of EC. Freeze-drying for more than 72 hours, in some cases augmented by prolonged aeration at room temperature, reduces EO, EC, and EG to acceptable levels. The accurate assay of residues in tissue requires acetone extraction for gas chromatography on rehydrated tissues because extraction of dry tissues gives falsely low results. Rigorous adherence to a protocol incorporating these findings justifies the acceptance of gaseous EO as a safe, relatively rapid, and inexpensive sterilant of bone and soft tissues.

Adult↗
PubMed1979

Autogenous skull cranioplasty: fresh and preserved (frozen), with consideration of the cellular response.

Every craniotomy requires immediate replacement of a fresh autograft of skull or, in the presence of cerebral swelling, delayed reimplantation of preserved autogenous skull. Resumption of osteogenesis, the index of viability, determines the effectiveness of these segments of calvaria in protecting the brain and restoring skull conformity. The cellular response in skull replaced either at the end of craniotomy or after frozen preservation was studied by light and fluorescence microscopy, skull roentgenograms, and radionuclide scintigraphy. In 5 patients eventual total remodeling of skull was found at the time of a second craniotomy performed from 1 to 19 years after the first. In 12 patients skull sections removed aseptically at craniotomy were frozen and stored for 1 to 35 months at -20 degrees C in bacitracin. This cytotoxic preservative method fixed the tissue, which appeared unchanged on light microscopy and was sterile on bacteriological and fungal cultures. In 53 patients who underwent autogenous cranioplasty with skull stored frozen for 3 weeks to 19 months, 48 operations were totally successful. Complications included infections in 2 patients, resorption in 2 infants, and incomplete restoration in 1 adult. In 10 patients the sequential dynamics of skull revitalization were found to be: revascularization, resorption, and accretion. The repair of membranous skull is similar to that of endochondral bone of the skeleton. Skull is metabolically intensely active after reimplantation and is the ideal material for cranioplasty.

Adolescent↗
PubMed1977

Balloon occlusion of carotid-cavernous fistula: introduction of a new catheter.

The most widely used technique for treatment of a carotid-cavernous fistula involves embolization of the fistula with segmental occlusion of the internal carotid artery. An inflatable balloon capping a small flexible catheter becomes a controlled embolus when positioned within the internal carotid artery at the stoma of the fistula. A new double lumen catheter has been designed. Through one lumen the carotid circulation may be displayed, The second lumen allows inflation of the balloon through a self-sealing valve. In twelve patients, results were excellent in eight, fair in two, and poor in two patients intolerant of carotid occlusion.

Adolescent↗