Experimental craniosynostosis in growing rabbits

1983 ◽  
Vol 58 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Dennis L. Nappen ◽  
Vincent G. Kokich
Keyword(s):  
New Zealand ◽  
The Other ◽  
Coronal Suture ◽  
Content Type ◽  
Metallic Implants ◽  
New Zealand White Rabbits ◽  
Parietal Bones ◽  
Fine Print

✓ Reports on the role of the periosteum in premature sutural synostosis have been contradictory. The present study summarizes a series of six experiments designed to clarify these previously conflicting findings. Twenty-five male New Zealand White rabbits were divided into six experimental groups. In four of the groups, methyl-2-cyanoacrylate was used to glue the frontal and parietal bones together and temporarily immobilize the coronal suture. In the other two groups, the sutures were not immobilized. Polyethylene was used to separate the cyanoacrylate from the periosteum in two of the groups. The experiments were performed at 5 weeks of age, and the animals were killed at either 30, 45, or 180 days postoperatively. Metallic implants were placed in the frontal and parietal bones for monitoring growth and/or sutural immobilization. Sutural fusion was confirmed radiographically or histologically. Based upon the findings it seems that mechanical immobilization of a suture does not induce fusion of that suture in rabbits. Furthermore, it appears that the mere application of methyl-2-cyanoacrylate to the periosteum overlying a suture will consistently cause the formation of a bony bridge in growing rabbits but not in nongrowing animals. The adhesive does not consistently induce synostosis if the periosteum is excised.

The effects of mechanical immobilization on sutural development in the growing rabbit

1980 ◽  
Vol 53 (6) ◽  
pp. 794-801 ◽  
Author(s):  
William J. Foley ◽  
Vincent G. Kokich
Keyword(s):  
New Zealand ◽  
Biological Response ◽  
Bone Union ◽  
Coronal Suture ◽  
Content Type ◽  
Bone Bridge ◽  
Age Related ◽  
New Zealand White Rabbits ◽  
The Brain ◽  
Fine Print

✓ Methyl-2-cyanoacrylate was used to mechanically immobilize the coronal suture unilaterally in a series of New Zealand white rabbits at varying ages. The animals were separated into groups; some were sacrificed at 30 days and some at 60 days postoperatively. Amalgam markers were placed in the parietal and frontal bones across the coronal suture, and were measured immediately after surgery and at the time of sacrifice to confirm mechanical immobility. The animals were studied radiographically and histologically in order to document the presence or absence of sutural bone union. Based on the results of this study, it appears that immobilization of the coronal suture results in the formation of an ectocranial periosteal bone bridge in rabbits less than 8 weeks of age. Bone union was not found in animals older than 8 weeks of age. This age-related difference in response is believed to be due to decreased periosteal depository activity on the ectocranial surface of the calvaria once the brain ceases to expand actively. Furthermore, bone union or synostosis was never seen within or across the internal portion of the sutural ligament. It is suggested, therefore, that sutural immobilization at young ages in the rabbit does not result in sutural synostosis and that the term “periosteal bone bridge” should be used when referring to this biological response.

Roentgen stereophotogrammetric analysis of neurocranial suturectomy in rabbits

1984 ◽  
Vol 60 (1) ◽  
pp. 158-165 ◽  
Author(s):  
Per Alberius ◽  
Göran Selvik ◽  
Leif Ekelund
Keyword(s):  
Bone Growth ◽  
Initial Rate ◽  
The Other ◽  
Cranial Vault ◽  
Coronal Suture ◽  
Content Type ◽  
Growth Disturbances ◽  
New Zealand White Rabbits ◽  
Control Volumes ◽  
Fine Print

✓ This investigation was conducted to further elucidate both the significance of a calvarial suture and the compensatory ability of the cranial vault. Four-week-old male New Zealand White rabbits were subjected to unilateral or bilateral extirpation of the coronal suture after insertion of metallic markers, and were then followed regularly by roentgen stereophotogrammetry until age 21 weeks. Bilateral extirpation of the normal coronal suture resulted in a dramatically increased initial rate of bone separation, which tended to remain supranormal for the rest of the investigation. Unilateral suturectomy showed differences in growth between the sides, the operated side initially separating significantly more than the other. Volumetric calvarial growth in rabbits with unilateral extirpation terminated similar to that in control animals, while volumes in rabbits with bilateral extirpations constantly exceeded control volumes, finally exceeding these by 65%. Responses at intact sutures confirmed the compensatory capacity of cranial vaults. The results indicate that the passive longitudinal and volumetric cranial vault bone growth responds quickly to growth disturbances, thereby demonstrating its plasticity, and that the neurocranial suture is a restraining and modulating component in cranial growth.

scholarly journals The effect of age, anatomical site and bone structure on osteogenesis in New Zealand White rabbit

2015 ◽  
Vol 88 (2) ◽  
Author(s):  
Francesca Ravanetti ◽  
Edoardo Scarpa ◽  
Vittorio Farina ◽  
Marco Zedda ◽  
Carlo Galli ◽  
...  
Keyword(s):  
New Zealand ◽  
Bone Structure ◽  
Skeletal Maturity ◽  
Zealand White Rabbit ◽  
Anatomical Site ◽  
Bone Implants ◽  
New Zealand White Rabbits ◽  
Preclinical Trials ◽  
Parietal Bones

Among animal models, rabbits are widely used in medical research, as they fill the gap between smaller models, commonly employed in basic science, and larger ones, which are better suited for preclinical trials. Given their rapid growth, rabbits provide a valuable system for the evaluation of bone implants for tissue regeneration. By means of a histomorphometric analysis, here we quantified the mineral apposition rates (MARs) in osteonic, periosteum and endosteum osteogenic fronts, of skeletal elements within femur, tibia, radius, ulna, frontal and parietal bones in New Zealand White rabbits aged 6, 7 and 8 months. Our hypothesis is that the MAR varies according to the skeletal maturity of the animal, and also within the skeletal elements and the osteogenic fronts considered. In the present study we show that the MAR in both femur and tibia is significantly higher than in ulna and radius. We also demonstrate that the MAR in parietal bones is significantly higher compared to the MAR of both frontal and forelimb bones. Contrary to what was expected, the MARs of all the skeletal elements considered were not decreased following full skeletal maturity. Finally, the MAR of the osteonic-osteogenic front is the lowest in all of the skeletal elements considered. In conclusion, these results provide new important insights for the evaluation of bone implants, casting a light on the role of both age and osteogenic fronts on the bone MAR, and providing valuable information on the physiological bone turnover in New Zealand White rabbits.

The intracerebral distribution of BCNU delivered by surgically implanted biodegradable polymers

1992 ◽  
Vol 76 (4) ◽  
pp. 640-647 ◽  
Author(s):  
Stuart A. Grossman ◽  
Carla Reinhard ◽  
O. Michael Colvin ◽  
Mark Chasin ◽  
Robert Brundrett ◽  
...  
Keyword(s):  
New Zealand ◽  
Brain Tissue ◽  
Direct Injection ◽  
Normal Brain ◽  
Local Concentration ◽  
Content Type ◽  
Drug Concentrations ◽  
New Zealand White Rabbits ◽  
The Brain ◽  
Fine Print

✓ The local concentration and distribution of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) within normal brain tissue were studied following surgical implantation of biodegradable polymer containing BCNU in New Zealand White rabbits. Cylindrical discs of poly(bis(p-carboxyphenoxy)-propane:sebacic acid) copolymer in a 20:80 formulation were made containing [3H]-inulin or [3H]-BCNU labeled in the methylene hydrogens of the chloroethyl groups. These were implanted in the brains of 56 New Zealand White rabbits. The animals were sacrificed 3, 7, 14, or 21 days later and the brains were rapidly removed, frozen, and prepared for quantitative autoradiography. Autoradiographs from coronal sections bisecting the polymer were analyzed to determine both the proportion of the brain section exposed to the tracer and the local drug concentrations as a function of distance from the polymer. Tritiated BCNU was also injected directly into the brains of eight additional rabbits, and local brain concentrations were studied over time. The results of this study demonstrate that approximately 50% of the area of the brain sections was exposed to radiolabeled compound 3 days after BCNU-polymer implantation, 15% at 7 days, and less than 10% at 14 and 21 days. Polymer discs containing 600 µg BCNU generated 6 mM concentrations of BCNU in brain tissue 10 mm from the polymer at 3 and 7 days. Pharmacological studies demonstrated that approximately 25% of the tritium label was associated with intact BCNU 3 days following polymer implantation. Radiolabeled inulin delivered by polymer remained dispersed throughout the ipsilateral hemisphere for 14 days. Direct injection of [3H]-BCNU into brain parenchyma resulted in widely distributed tracer at 1 and 3 hours with rapid disappearance thereafter. It is concluded that local delivery of BCNU to brain tissue with this polymeric drug delivery system results in sustained high local concentrations of BCNU which may be of value in the treatment of patients with brain tumors.

Aphasia and left thalamic hemorrhage

1978 ◽  
Vol 48 (4) ◽  
pp. 570-574 ◽  
Author(s):  
Arden F. Reynolds ◽  
A. Basil Harris ◽  
George A. Ojemann ◽  
Paul T. Turner
Keyword(s):  
Acute Onset ◽  
The Other ◽  
Content Type ◽  
Thalamic Hemorrhage ◽  
Fine Print

✓ Left thalamic hemorrhage as a cause of aphasia has not been widely recognized. Large thalamic hemorrhages cause coma, making speech examination impossible; smaller thalamic hemorrhages were difficult to document until recent diagnostic advances. Nine cases of thalamic hemorrhage with aphasia have been described in the literature. This report presents four additional cases. These patients had acute onset of aphasia, supranuclear paralysis of upward gaze, right hemisensory deficits, and mild right hemiparesis. Three of the four patients responded to ventriculostomy drainage with rapid clearing of the supranuclear paralysis of upward gaze, and two later required placement of permanent ventricular shunts. After 1 year, two patients exhibited no clinically detectable speech malfunction and the other two were severely aphasic. The hemiparesis, hemisensory deficits, and ocular pareses all cleared. These cases are discussed with respect to present models of the role of the thalamus in speech.

The use of bone morphogenetic protein—6 gene therapy for percutaneous spinal fusion in rabbits

2004 ◽  
Vol 1 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Jeffrey J. Laurent ◽  
K. Michael Webb ◽  
Elisa J. Beres ◽  
Kevin McGee ◽  
Jinzhong Li ◽  
...  
Keyword(s):  
Gene Therapy ◽  
New Zealand ◽  
Spinal Fusion ◽  
Ct Scanning ◽  
Content Type ◽  
Morphogenetic Protein ◽  
New Zealand White Rabbits ◽  
Percutaneous Administration ◽  
Multiple Levels ◽  
Fine Print

Object. Fusion procedures in the lumbar spine have been performed in the US since 1911. Since that time, the indications and techniques for spinal fusion have evolved. Despite technical advancements, spinal fusion remains a major operation, and fusion nonunion rates of up to 35% are still reported. In this study, the authors were able to induce intertransverse process fusions in immune-competent New Zealand White rabbits by percutaneous administration of an adenoviral vector containing the bone morphogenetic protein (BMP-6) gene (Ad-BMP-6). The results represent an important step forward in finding new methods to increase the success and decrease the morbidity associated with spinal fusion. Methods. Five New Zealand White rabbits were used. Injection of the adenoviral construct was performed at multiple levels (bilaterally) in each animal while using fluoroscopic guidance. Injection consisted of either Ad-BMP-6 or Ad—β-galactosidase (β-gal) (control). Because multiple levels were injected, each animal served as an internal control. The animals underwent postinjection computerized tomography (CT) scanning at 7 and 14 weeks. After undergoing final CT scanning, the animals were killed and the spines were harvested. The fusion sites were analyzed by gross inspection, histopathological methods, and micro—CT studies. Conclusions. The results of this study show that an anatomically precise fusion can be accomplished by percutaneous administration of gene therapy. The next step in these studies will be extension of the technique to nonhuman primates and eventually to human clinical studies.

Skull growth after coronal suturectomy, periostectomy, and dural transection

1982 ◽  
Vol 56 (4) ◽  
pp. 529-535 ◽  
Author(s):  
William J. Babler ◽  
John A. Persing ◽  
K. Maurits Persson ◽  
H. Richard Winn ◽  
John A. Jane ◽  
...  
Keyword(s):  
Dura Mater ◽  
Normal Growth ◽  
Coronal Suture ◽  
Falx Cerebri ◽  
Content Type ◽  
Total Length ◽  
Skull Growth ◽  
Parietal Bones ◽  
Fine Print

✓ Using radiocephalometric procedures, the authors examined the separate effects of suturectomy, periostectomy, and dural transection on the growing skull in young rabbits. When the coronal suture was surgically removed during normal growth, the freed frontal and parietal bones separated at a significantly accelerated rate. No accelerated separation was found when only the overlying periosteum and aponeurosis were transected. Furthermore, no additional separation was observed when the dura mater and falx cerebri were transected following suturectomy. Analysis of growth at the adjacent frontonasal and anterior lambdoid sutures suggested that the accelerated separation of bones after suturectomy was compensated for by reduced growth at these adjacent sutures. The result of these compensatory actions was that the total length of the skull remained unchanged. This study not only supports earlier observations that sutures grow in response to extrinsic separative forces but, significantly, that the suture tissue itself, rather than the dura or pericranium, acts as a restraint during normal translatory growth.

Craniosynostosis in vitamin D-resistant rickets

1981 ◽  
Vol 55 (2) ◽  
pp. 265-271 ◽  
Author(s):  
William A. Roy ◽  
Robert J. Iorio ◽  
Glenn A. Meyer
Keyword(s):  
Vitamin D ◽  
Animal Model ◽  
Coronal Suture ◽  
Content Type ◽  
Vitamin D Resistant Rickets ◽  
New Treatment ◽  
Treatment Procedures ◽  
Fine Print ◽  
Resistant Rickets

✓ Craniosynostosis and associated craniofacial deformities, such as frontal bossing, often occur as symptoms of vitamin D-resistant rickets in children. Similar skull deformities develop in mice with X-linked dominant hypophosphatemia, the most common form of vitamin D-resistant rickets. These mice have a short, wide, high neurocranium, which suggested an inhibition of coronal suture growth. To study this question, we compared histologically the postnatal development of the coronal sutures in normal and hypophosphatemic mice between 1 and 13 weeks of age. Premature fusion of the coronal suture occurred in hypophosphatemic mice by 4 weeks of age. The proportion of the suture obliterated by bone varied among individual animals, but craniosynostosis was present in all animals studied at 4 weeks and older. Fusion of the coronal suture did not occur through 13 weeks of age in any of the normal mice studied. The X-linked hypophosphatemic mouse is an animal model that can be used to study the role of vitamin Dresistant rickets in the development of craniosynostosis, to relate craniosynostosis to the development of associated skull deformities, and to test new treatment procedures.

Computerized tomography studies of congenital and acquired cerebral intraventricular membranes

1981 ◽  
Vol 54 (3) ◽  
pp. 388-391 ◽  
Author(s):  
Edward R. Savolaine ◽  
Arthur M. Gerber
Keyword(s):  
Computerized Tomography ◽  
Antibiotic Treatment ◽  
Plain Film ◽  
The Other ◽  
Ct Scans ◽  
Shunt Failure ◽  
Content Type ◽  
Complicated Course ◽  
Fine Print

✓ The role of intraventricular membranes in recurrent shunt failure is explored in two cases using computerized tomography (CT) with intraventricular metrizamide and air ventriculography. One patient who had hydrocephalus with congenital intraventricular membranes containing neurons had a good ultimate response, although he had undergone seven shunt revisions before the membranes were discovered. The other patient with postventriculitis membranes had a complicated course. The effects of shunt malposition and intraventricular antibiotic treatment are discussed. It is determined that certain clues from CT scans, plain film, and air ventriculography may indicate the presence of membranes contributing to repeated shunt failure and that the use of intraventricular metrizamide with CT facilitates the diagnosis.

Posterior approach for cervical intramedullary arteriovenous malformation with diffuse-type nidus

1999 ◽  
Vol 91 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Kenji Ohata ◽  
Toshihiro Takami ◽  
Alaa El-Naggar ◽  
Michiharu Morino ◽  
Akimasa Nishio ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Poor Prognosis ◽  
Posterior Approach ◽  
The Other ◽  
Anterior Spinal Artery ◽  
Neural Element ◽  
Feeding Artery ◽  
Diffuse Type ◽  
Content Type ◽  
Fine Print

✓ The treatment of spinal intramedullary arteriovenous malformations (AVMs) with a diffuse-type nidus that contains a neural element poses different challenges compared with a glomus-type nidus. The surgical elimination of such lesions involves the risk of spinal cord ischemia that results from coagulation of the feeding artery that, at the same time, supplies cord parenchyma. However, based on evaluation of the risks involved in performing embolization, together with the frequent occurrence of reperfusion, which necessitates frequent reembolization, the authors consider surgery to be a one-stage solution to a disease that otherwise has a very poor prognosis. Magnetic resonance (MR) imaging revealed diffuse-type intramedullary AVMs in the cervical spinal cords of three patients who subsequently underwent surgery via the posterior approach. The AVM was supplied by the anterior spinal artery in one case and by both the anterior and posterior spinal arteries in the other two cases. In all three cases, a posterior median myelotomy was performed up to the vicinity of the anterior median fissure that divided the spinal cord together with the nidus, and the feeding artery was coagulated and severed at its origin from the anterior spinal artery. In the two cases in which the posterior spinal artery fed the AVM, the feeding artery was coagulated on the dorsal surface of the spinal cord. Neurological outcome improved in one patient and deteriorated slightly to mildly in the other two patients. Postoperative angiography demonstrated complete disappearance of the AVM in all cases. Because of the extremely poor prognosis of patients with spinal intramedullary AVMs, this surgical technique for the treatment of diffuse-type AVMs provides acceptable operative outcome. Surgical intervention should be considered when managing a patient with a diffuse-type intramedullary AVM in the cervical spinal cord.

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