Recherche de résistance des os de théropode
Discussion:
36 836
25
Dernière réponse
36 836
25
Dernière réponse
Posté par Pyroraptor
Voila pour finir mon étude sur ce fameux spinosaures il me manque juste la résistance des os d'un dino de préference un théropode
Posté par Yoyo
Les os des théropode était assez fragile comme le montre le spécimen d'allosaure "big all". par exemple, un tyrannosaurus rex tombat à un vitessse de 20 k/h se serait fracturer le crane et le tibia. malgré tout, leur os se cicatrisait vite et efficacement: comme le montre un nouvelle fois le spécimen de big all, son sqeulette à subi en tout 14 fractures, mais ses os se sont tous resoudé.
Posté par Pyroraptor
Sa je le savais mais ce que je ne sais pas c'est le chiffre je sais pas moi une résistance de 6000 newton/m2 ou j'en sais rien
Posté par Yoyo
Possible, il fallait voir d'abors la puissance des machoire des théropode: à partir de la résistance des os d'hadrosaure, on peut estimer la puissance de la machoire, et si on connait la puissance de la machoire, on connait la résistance des os! compris?
Posté par Pyroraptor
Ben oui mais tu as un chiffre? je sais qu'une étude a était mené pour sue je crois mais je n'arrive pas a trouvé de chiffres
Posté par Yoyo
Ah ça, il faut attendre gigy et son les autres spécialistes assoifés de sang... 
Posté par Kuzanaguy
ce n est pas parcque big all avait beaucoup de fracture que les therodes avaient par consequent les os fragiles.de plus il pouvait peu etre contracter une maladie osseuse ou comme plusieurs specialistes avance l idée =big all était un allosaure hyperactif et agressif.de plusl a solidité d un os n est pas la meme par rapport a un choc lateral ou transversal,donc le problème est beaucoup plus compliqué que cela.si les theropodes avaient vraiment les os fragiles je ne vois pas comment ils aurraient pu conserver une locomotion bipedique tout en depassant des poids de plus de 5 à 6 tonnes c est tout bonnement illogique.
Posté par Para
J'ai ça
http://www.ismni.org/jmni/pdf/22/08FYHRIE-SUMMARY.pdf
http://www.ismni.org/jmni/pdf/22/08FYHRIE-SUMMARY.pdf
Posté par Pyroraptor
Merci para mais je pense que si j'arrive a trouver l'étude éffectué sur Sue je pense que se sera mieux car la si je ne me trompe pas c'est une qualité d'os mais aprés fossilisation en faites ce que je cherche c'est la qualitée des os d'un spinosaurus en pleine forme 
Posté par Tikémi
Tu parles du travail réalisé par Brochu ?
Si je ne me trompe pas, il a fait toute une étude sur sue qu'il a passée au scanner
folio spécial de JVP.
Si c'est ça que tu veux, je l'ai au bureau, je pourrais essayer de te trouver l'info vite fait (mais pas avant mardi soir because congés ).
Si je ne me trompe pas, il a fait toute une étude sur sue qu'il a passée au scanner
folio spécial de JVP.Si c'est ça que tu veux, je l'ai au bureau, je pourrais essayer de te trouver l'info vite fait (mais pas avant mardi soir because congés
).
Posté par Lolo
Je dois avoir ça aussi ... ça fait plus de 150 pages à fouiller quand même 
Posté par Tikémi
Faut mettre le radar pour que ça aille plus vite.
Posté par Pyroraptor
oui ce serait bien si vous arriviez a me trouver sa 
ou meme si vous avez les 150 pages a me passer je peux les décortiquer sinon
Posté par Kuzanaguy
Ne postez pas avant que j ai fini les recherches=
FRACTURE MANAGEMENT IN REPTILES
R. Avery Bennett, DVM, MS, Diplomate ACVS
University of Florida, College of Veterinary Medicine, Gainesville, FL
Introduction:
Fractures of the extremities in reptiles are rarely open or comminuted. Many fractures, especially pathologic fractures secondary to metabolic bone disease, are amenable to treatment using external coaptation. In other situations, internal fixation is indicated. Fractures have been successfully stabilized with various forms of internal fixation. In patients with metabolic bone disease, calcium homeostasis must be re-established. This requires medical management while supporting any pathologic fractures. When there is severe tissue trauma, loss of vascular supply, or granulomatous infection and inflammation, amputation may be required. Reptiles generally function well with partial or complete limb amputations.
Long bone fractures in reptiles are usually the result of trauma or metabolic bone disease.1 Most fractures occur as a result of relatively low impact forces, making the incidence of comminuted fractures low.2,3 Most reptiles have tough, yet elastic skin and fractures are not usually open. Little information is available regarding bone healing in reptiles; however, it appears that it occurs at a significantly slower rate when compared to birds and mammals. Healing time for traumatic fractures is generally 6-18 mo. Pathologic fractures from metabolic bone disease seem to heal much more quickly following correction of the hypocalcemia (6-8 wk) and treatment with synthetic salmon calcitonin.
General principles of fracture fixation apply to reptile patients - rigid stabilization and anatomic alignment with minimal disruption of callus and soft tissues. Many factors must be considered when deciding on the method of fixation to be used. The forces exerted on the fracture (bending, compression, rotation, and shear) must be neutralized to promote healing. Generally, the more forces that must be neutralized by the fixation, the higher the incidence of complications and failure. Practical consideration include the patient's functional requirements, cost of the materials, ease of application, availability of equipment, and the surgeon's level of experience with various fixation devices. Most closed fractures in reptiles will heal without intervention with varying degrees of malunion.2,3 This may be acceptable in some patients. The patient's size and conformation may influence the type of device used and how it is applied. The general health and metabolic status of the patient may preclude a surgical procedure for orthopedic repair. Finally, financial concerns must often be considered.
External Coaptation - External coaptation involves the use of splints, slings, and other bandages to immobilize a fracture. This is probably the most commonly used method of fracture fixation in reptile orthopedics because it is simple, requires little equipment, takes only a short time to apply and a brief anesthesia period, and generally is the least expensive. Fractures which are minimally displaced usually heal with minimal support.
When dealing with pathologic fractures secondary to metabolic bone disease, external coaptation is usually the treatment of choice. Metabolic bone disease is a complex disease in reptiles with many causes and factors contributing to its development.4 It is one of the clinical manifestations of prolonged hypocalcemia and occurs most commonly in green iguanas, but can occur in anycaptive reptile. Hypocalcemia in reptiles may be the result of improper diet, the presence of organic disease, or failure to provide proper husbandry. Because bone is dynamic (undergoing constant remodeling), during prolonged hypocalcemia the mineralization process lags behind the deposition of organic bone matrix resulting in the formation of hypomineralized bone (fig. 1). Orthopedic abnormalities occur when the bone loses approximately one third of its calcium content. Orthopedic problems associated with metabolic bone disease include stunted
FRACTURE MANAGEMENT IN REPTILES
R. Avery Bennett, DVM, MS, Diplomate ACVS
University of Florida, College of Veterinary Medicine, Gainesville, FL
Introduction:
Fractures of the extremities in reptiles are rarely open or comminuted. Many fractures, especially pathologic fractures secondary to metabolic bone disease, are amenable to treatment using external coaptation. In other situations, internal fixation is indicated. Fractures have been successfully stabilized with various forms of internal fixation. In patients with metabolic bone disease, calcium homeostasis must be re-established. This requires medical management while supporting any pathologic fractures. When there is severe tissue trauma, loss of vascular supply, or granulomatous infection and inflammation, amputation may be required. Reptiles generally function well with partial or complete limb amputations.
Long bone fractures in reptiles are usually the result of trauma or metabolic bone disease.1 Most fractures occur as a result of relatively low impact forces, making the incidence of comminuted fractures low.2,3 Most reptiles have tough, yet elastic skin and fractures are not usually open. Little information is available regarding bone healing in reptiles; however, it appears that it occurs at a significantly slower rate when compared to birds and mammals. Healing time for traumatic fractures is generally 6-18 mo. Pathologic fractures from metabolic bone disease seem to heal much more quickly following correction of the hypocalcemia (6-8 wk) and treatment with synthetic salmon calcitonin.
General principles of fracture fixation apply to reptile patients - rigid stabilization and anatomic alignment with minimal disruption of callus and soft tissues. Many factors must be considered when deciding on the method of fixation to be used. The forces exerted on the fracture (bending, compression, rotation, and shear) must be neutralized to promote healing. Generally, the more forces that must be neutralized by the fixation, the higher the incidence of complications and failure. Practical consideration include the patient's functional requirements, cost of the materials, ease of application, availability of equipment, and the surgeon's level of experience with various fixation devices. Most closed fractures in reptiles will heal without intervention with varying degrees of malunion.2,3 This may be acceptable in some patients. The patient's size and conformation may influence the type of device used and how it is applied. The general health and metabolic status of the patient may preclude a surgical procedure for orthopedic repair. Finally, financial concerns must often be considered.
External Coaptation - External coaptation involves the use of splints, slings, and other bandages to immobilize a fracture. This is probably the most commonly used method of fracture fixation in reptile orthopedics because it is simple, requires little equipment, takes only a short time to apply and a brief anesthesia period, and generally is the least expensive. Fractures which are minimally displaced usually heal with minimal support.
When dealing with pathologic fractures secondary to metabolic bone disease, external coaptation is usually the treatment of choice. Metabolic bone disease is a complex disease in reptiles with many causes and factors contributing to its development.4 It is one of the clinical manifestations of prolonged hypocalcemia and occurs most commonly in green iguanas, but can occur in anycaptive reptile. Hypocalcemia in reptiles may be the result of improper diet, the presence of organic disease, or failure to provide proper husbandry. Because bone is dynamic (undergoing constant remodeling), during prolonged hypocalcemia the mineralization process lags behind the deposition of organic bone matrix resulting in the formation of hypomineralized bone (fig. 1). Orthopedic abnormalities occur when the bone loses approximately one third of its calcium content. Orthopedic problems associated with metabolic bone disease include stunted
Posté par Kuzanaguy
Growth, malleable mandibles with loose teeth (rubber jaw), firm fibrous swelling (fibrous osteodystrophy) of the mandible and long bones, bowing of the long bones, and pathologic fractures of the axial and appendicular skeleton.
These fractures are difficult to stabilize using internal fixation because the bone is too soft to support implants. If when Steinmann pins are inserted they contact a cortex, they penetrate rather than being diverted down the medullary canal. Cerclage, hemicerclage, and interfragmentary wires collapse the soft bone. Bone screws have minimal resistance to pulling out when placed in such soft bone. Similarly, external skeletal fixation does not function well as the bone purchase of the fixation pins is minimal. In some cases IM pins may be carefully inserted to provide axial alignment and some bending stability; however, external coaptation should be applied in addition as cortical purchase may be minimal. Fortunately, once the patient's calcium homeostasis has been reestablished, fracture healing progresses rapidly with a fibrous union providing stability as early as 3-4 wk. Medical therapies for hypocalcemia have been described.4 It appears that salmon derived calcitonin (Miacalcin, 100 IU/ml, Schering Plough) at a dose of 50 IU/kg IM administered weekly in the front leg for two treatments may speed recovery from metabolic bone disease by blocking the action of parathyroid hormone and inhibiting bone resorption.5 It is crucial that the patient be normocalcemic prior to the administration of calcitonin.
A wide variety of splinting and casting techniques have been used successfully.1,2,6-9 Anesthesia is recommended during the application of external coaptation to prevent iatrogenic fractures or comminutions and to minimize patient stress. All forms of external coaptation should be monitored closely for evidence of soiling, slippage, creating vascular compromise, or other problems which may require splint replacement.
Soft, conforming cast padding (Specialist Cast Padding, Johnson & Johnson, New Brunswick, NJ; Webril, Kendall Co., Boston, MA) and conforming roll gauze (Conform, Kendall Co., Boston, MA) work well for the initial padding layers. These materials should be cut to an appropriate width for the size of the patient. Using a roll that is too wide will result in a lumpy, cumbersome bandage. The bandage may be reinforced with a wood applicator stick, a tongue depressor, an aluminum rod, light weight casting material, or other substance that will add bending stability. Most of these do not conform to the normal angles of a reptile limb necessitating that the limb be splinted in extension. This can result in a decrease in the range of motion in immobilized joints due to periarticular fibrosis (fracture disease).
Orthoplast (Johnson & Johnson, New Brunswick, NJ), Hexcelite (Hexcel Medical, Dublin, CA), and Veterinary Thermoplastic (VTP) (IMEX Veterinary, Inc., Longview, TX) are rigid at room temperature but when heated in water become malleable. This allows the material to conform closely to the configuration of the limb. Orthoplast is a solid sheet while Hexcelite is a webbing available in roll or sheet form. The Hexcelite is much easier to conform but is not as rigid when cool. VTP is available in various sizes and thicknesses. It is a solid sheet with a fiber mesh reinforcement within plastic. It is easily cut to an appropriate size and is more malleable than Orthoplast and more rigid than Hexcelite, making it ideally suited for use as a splint.
In applying a splint, tape stirrups may be applied to the skin to be incorporated into the bandage and prevent slippage. The first layer should consist of some type of padding material - cotton or cast padding. The padding is compressed with an expansile wrap such as conforming gauze, bandaging tape (Vetrap; 3M Animal Care Products, St. Paul, MN), or elastic tape (Elasticon; Johnson & Johnson Medical, Inc, Arlington, TX). If no reinforcing splint is necessary, elastic tape or bandaging tape should be used. If a splint material is to be added, conforming gauze should be applied. The splint should be placed external to the gauze and covered with a final layer of bandaging tape or elastic tape.
Tubular traction splints may be used to treat fractures of the crus, antebrachium, distal humerus, and distal femur (fig. 2). A tube such as a syringe case of a diameter appropriate to the size of the patient's limb is padded at its proximal end. Tape stirrups are applied to the limb and secured to it. Padding is added to the limb to limit movement within the tube. The tape is then pulled through the tube such that the padded end is forced into the inguinal/axillary region and the limb is maintained in traction. The tape is secured to the outside of the tube maintaining the leg in extension and traction. The disadvantage of this type of splint is that it maintains the limb in complete extension. This can result in a decrease in the range of motion in immobilized joints due to periarticular fibrosis (fracture disease).
The bone involved and the conformation of the patient will also influence the type of coaptation used. For example, it would not be possible to adequately stabilize a humerus fracture in a chelonian with a traditional splint as the joint proximal to the fracture would not be immobilized. In chelonians with a fractured humerus or femur, the limb may be folded into the cavity created between the plastron and the carapace and taped in place preventing movement. Unfortunately, this does not address fracture alignment; however, the resulting malunion may be acceptable.
In lizards, fractures of the humerus or femur may be stabilized with a modified spica splint which will cross over the pelvic or pectoral girdle to the opposite limb, thereby stabilizing the hip or shoulder joint and achieving the goal of immobilizing the joints proximal and distal to the fracture10. Most lizards stand relatively flat or low with respect to the substrate and use abdominal undulation as an aid to locomotion allowing them the ability to ambulate even with this type of device. With fractures of the pelvic limb the splint should cross midline dorsally to allow normal voiding, while with fractures of the pectoral limb it should cross ventrally (fig. 3).
Internal Fixation - Internal fixation is indicated for repair of most severe long bone fractures in reptiles.2,3 External coaptation frequently does not provide rigid stabilization and is frequently not well tolerated by reptile patients.2,3 External coaptation is not feasible in aquatic and semiaquatic reptiles. Virtually all methods for internal fracture fixation have been used successfully in reptiles.2,3,6,7,11-14 Surgical approaches to the long bones and the principles of application of internal fixation in reptiles are similar to those used in mammalian patients.2,3
Intramedullary Steinmann pins and orthopedic wires are very familiar to most veterinarians. They are inexpensive, provide axial alignment and bending stability, and require minimal tissue exposure for insertion. Kirschner wires may be used as IM pins and are available in sizes as small as 0.028 in. Spinal needles are available as small as 25 ga x 3.5 in and may also be used as IM pins.
External skeletal fixation (ESF) may be used for stabilizing a variety of fractures in reptiles. These devices provide good stability without interfering with joints and may be applied even to very small patients. In reptiles they are most often applied parallel to the substrate in a cranial to caudal plane rather than a medial to lateral plane as in mammals because of their different method of ambulation. Biphasic ESF devices use various size Kirschner wires, Steinmann pins, or hypodermic needles as fixation pins but the connecting bar and clamps are replaced by acrylic polymer or other rigid material. This modification makes the apparatus less expensive and more lightweight.
In fracture management with ESF pin loosening will occur for a variety of reasons and the success of the repair depends on the ability of the bone to heal before the fixation pins loosen and the device fails. Because reptile bones heal slowly, the pins are more likely to
These fractures are difficult to stabilize using internal fixation because the bone is too soft to support implants. If when Steinmann pins are inserted they contact a cortex, they penetrate rather than being diverted down the medullary canal. Cerclage, hemicerclage, and interfragmentary wires collapse the soft bone. Bone screws have minimal resistance to pulling out when placed in such soft bone. Similarly, external skeletal fixation does not function well as the bone purchase of the fixation pins is minimal. In some cases IM pins may be carefully inserted to provide axial alignment and some bending stability; however, external coaptation should be applied in addition as cortical purchase may be minimal. Fortunately, once the patient's calcium homeostasis has been reestablished, fracture healing progresses rapidly with a fibrous union providing stability as early as 3-4 wk. Medical therapies for hypocalcemia have been described.4 It appears that salmon derived calcitonin (Miacalcin, 100 IU/ml, Schering Plough) at a dose of 50 IU/kg IM administered weekly in the front leg for two treatments may speed recovery from metabolic bone disease by blocking the action of parathyroid hormone and inhibiting bone resorption.5 It is crucial that the patient be normocalcemic prior to the administration of calcitonin.
A wide variety of splinting and casting techniques have been used successfully.1,2,6-9 Anesthesia is recommended during the application of external coaptation to prevent iatrogenic fractures or comminutions and to minimize patient stress. All forms of external coaptation should be monitored closely for evidence of soiling, slippage, creating vascular compromise, or other problems which may require splint replacement.
Soft, conforming cast padding (Specialist Cast Padding, Johnson & Johnson, New Brunswick, NJ; Webril, Kendall Co., Boston, MA) and conforming roll gauze (Conform, Kendall Co., Boston, MA) work well for the initial padding layers. These materials should be cut to an appropriate width for the size of the patient. Using a roll that is too wide will result in a lumpy, cumbersome bandage. The bandage may be reinforced with a wood applicator stick, a tongue depressor, an aluminum rod, light weight casting material, or other substance that will add bending stability. Most of these do not conform to the normal angles of a reptile limb necessitating that the limb be splinted in extension. This can result in a decrease in the range of motion in immobilized joints due to periarticular fibrosis (fracture disease).
Orthoplast (Johnson & Johnson, New Brunswick, NJ), Hexcelite (Hexcel Medical, Dublin, CA), and Veterinary Thermoplastic (VTP) (IMEX Veterinary, Inc., Longview, TX) are rigid at room temperature but when heated in water become malleable. This allows the material to conform closely to the configuration of the limb. Orthoplast is a solid sheet while Hexcelite is a webbing available in roll or sheet form. The Hexcelite is much easier to conform but is not as rigid when cool. VTP is available in various sizes and thicknesses. It is a solid sheet with a fiber mesh reinforcement within plastic. It is easily cut to an appropriate size and is more malleable than Orthoplast and more rigid than Hexcelite, making it ideally suited for use as a splint.
In applying a splint, tape stirrups may be applied to the skin to be incorporated into the bandage and prevent slippage. The first layer should consist of some type of padding material - cotton or cast padding. The padding is compressed with an expansile wrap such as conforming gauze, bandaging tape (Vetrap; 3M Animal Care Products, St. Paul, MN), or elastic tape (Elasticon; Johnson & Johnson Medical, Inc, Arlington, TX). If no reinforcing splint is necessary, elastic tape or bandaging tape should be used. If a splint material is to be added, conforming gauze should be applied. The splint should be placed external to the gauze and covered with a final layer of bandaging tape or elastic tape.
Tubular traction splints may be used to treat fractures of the crus, antebrachium, distal humerus, and distal femur (fig. 2). A tube such as a syringe case of a diameter appropriate to the size of the patient's limb is padded at its proximal end. Tape stirrups are applied to the limb and secured to it. Padding is added to the limb to limit movement within the tube. The tape is then pulled through the tube such that the padded end is forced into the inguinal/axillary region and the limb is maintained in traction. The tape is secured to the outside of the tube maintaining the leg in extension and traction. The disadvantage of this type of splint is that it maintains the limb in complete extension. This can result in a decrease in the range of motion in immobilized joints due to periarticular fibrosis (fracture disease).
The bone involved and the conformation of the patient will also influence the type of coaptation used. For example, it would not be possible to adequately stabilize a humerus fracture in a chelonian with a traditional splint as the joint proximal to the fracture would not be immobilized. In chelonians with a fractured humerus or femur, the limb may be folded into the cavity created between the plastron and the carapace and taped in place preventing movement. Unfortunately, this does not address fracture alignment; however, the resulting malunion may be acceptable.
In lizards, fractures of the humerus or femur may be stabilized with a modified spica splint which will cross over the pelvic or pectoral girdle to the opposite limb, thereby stabilizing the hip or shoulder joint and achieving the goal of immobilizing the joints proximal and distal to the fracture10. Most lizards stand relatively flat or low with respect to the substrate and use abdominal undulation as an aid to locomotion allowing them the ability to ambulate even with this type of device. With fractures of the pelvic limb the splint should cross midline dorsally to allow normal voiding, while with fractures of the pectoral limb it should cross ventrally (fig. 3).
Internal Fixation - Internal fixation is indicated for repair of most severe long bone fractures in reptiles.2,3 External coaptation frequently does not provide rigid stabilization and is frequently not well tolerated by reptile patients.2,3 External coaptation is not feasible in aquatic and semiaquatic reptiles. Virtually all methods for internal fracture fixation have been used successfully in reptiles.2,3,6,7,11-14 Surgical approaches to the long bones and the principles of application of internal fixation in reptiles are similar to those used in mammalian patients.2,3
Intramedullary Steinmann pins and orthopedic wires are very familiar to most veterinarians. They are inexpensive, provide axial alignment and bending stability, and require minimal tissue exposure for insertion. Kirschner wires may be used as IM pins and are available in sizes as small as 0.028 in. Spinal needles are available as small as 25 ga x 3.5 in and may also be used as IM pins.
External skeletal fixation (ESF) may be used for stabilizing a variety of fractures in reptiles. These devices provide good stability without interfering with joints and may be applied even to very small patients. In reptiles they are most often applied parallel to the substrate in a cranial to caudal plane rather than a medial to lateral plane as in mammals because of their different method of ambulation. Biphasic ESF devices use various size Kirschner wires, Steinmann pins, or hypodermic needles as fixation pins but the connecting bar and clamps are replaced by acrylic polymer or other rigid material. This modification makes the apparatus less expensive and more lightweight.
In fracture management with ESF pin loosening will occur for a variety of reasons and the success of the repair depends on the ability of the bone to heal before the fixation pins loosen and the device fails. Because reptile bones heal slowly, the pins are more likely to
Posté par Pyroraptor
Je cmprends rien 
Posté par Kuzanaguy
Loosen before the fracture is stable. Pin purchase can be maximized by using threaded pins (preferably with the threads applied onto the pin, not cut into it) and inserting the fixation pins in the proper manner as outlined by Egger.15
Bone plating often requires a relatively large patient; however, with the recent availability of the veterinary cuttable plates (Synthes, Paoli, PA) with screws as small as 1.5 mm diameter (1.1 mm core diameter) bones as small as 3 mm diameter may be plated. Finger plates are also applicable to many long bone fractures in reptiles. Bone plating is often the treatment of choice for stabilizing femur and humerus fractures in chelonians. In some reptiles, especially varanids, long bones are curved. In large patients, 2.7 mm reconstruction plates may be used to allow the plate to be contoured to such bones. Of course, bone plating is expensive and requires specific expertise.
In most cases, removal of bone plates is not recommended. With IM pins or ESF, the decision to remove implants should be based on radiographic evidence of bone healing. In some cases, a fibrous union may provide adequate stability allowing fracture healing to proceed to completion if the implants fail or must be removed prior to the development of radiographic union.
Limb Amputation - Phalanges or an entire digit may be amputated with good cosmetic result. When a digit is to be amputated, the incision should be planned to allow the skin closure to be flush with the metacarpal or metatarsal portion of the foot creating a stumpless, cosmetic, functional appendage. Two skin flaps are created with the plantar/palmar flap being longer than the dorsal. When the two flaps are brought together in apposition the incision will be elevated from the substrate making it less likely to become severely contaminated or traumatized by the substrate.
In most animals where limb amputation is indicated, it is recommended that amputation be performed as proximal as possible to prevent the patient from traumatizing the stump on its substrate. This technique has also been recommended for reptiles; however most reptiles have very tough skin which is resistant to such trauma. Their scar tissue, however, is more delicate and easily abraded. Further, because most lizards stand flat or low to the ground even a short stump may aid in locomotion. When a limb must be amputated in a lizard, if the patient may benefit from the ability to use the stump it may be amputated in a location which will provide a stump that will aid in ambulation. The skin should be incised to create a flap on the ventral surface which will be placed over the end of the stump and sutured dorsally (fig. 4). This will place healthy, normal skin in contact with the substrate and the incision/scar tissue dorsal and lateral. The end of the bone should be padded with viable soft tissues prior to skin closure.
In many cases, because of the nature of the trauma or the presence of infection along fascial planes, the entire limb must be removed. This is best performed at the scapulo humeral or the coxofemoral joint. Muscles should be transected at their distal insertions to allow for adequate soft tissue coverage of the site. The muscle bellies are then elevated from the periosteum proximally until the articulation is exposed. Smooth transection of the nerves with a scalpel is recommended.16 The nerves may be injected with bupivicaine to provide local anesthesia minimizing postoperative pain.
In chelonians it is usually best to amputate as proximal as possible since they stand more upright and are more likely to traumatize their stump. A prosthesis may be provided by securing a wood block, furniture coaster, or wheel on the plastron ventral to the shoulder or hip joint secured using an acrylic cement. This will elevate the affected corner of the shell allowing easier ambulation using the remaining limbs.
In most reptiles, a tail that has been traumatized may be amputated back to healthy tissue, especially when vertebrae are exposed. Many lizards and some snakes seem able to voluntarily break off their tail by a process called autotomy in an effort to escape from a predator. They have the ability to regenerate the lost portion of their tail.17 The regenerated segment contains a cartilaginous rod and a different scale and color pattern. Primary closure of the exposed end will prevent regeneration. In handling these species, care must be taken to avoid autotomy. In some instances only a partial autotomy occurs. The distal segment may retain it vascular integrity allowing the defect to heal with a better cosmetic result. A padded tubular splint should be applied to prevent progression of the defect during tail movement.2,3,18
REFERENCES
1. Marcus LC: Veterinary Biology and Medicine of Captive Amphibians and Reptiles. Philadelphia, PA, Lea & Febiger, 1981, pp 77-79.
2. Frye FL: Biomedical and Surgical Aspects of Captive Reptile Husbandry. Edwardsville, KS, Veterinary Medicine Publishing Co, 1981, pp 247-278.
3. Frye FL: Biomedical and Surgical Aspects of Captive Reptile Husbandry (ed 2). Malabar, FL, Krieger Publishing Co, 1991, pp 461-465.
4. Burgmann PM, McFarlen J, Thiesenhausen K: Causes of hypocalcemia and metabolic bone disease in Iguana iguana. J Sm Ex Anim Med 2(2):63-68, 1993.
5. Mader DR: Use of calcitonin in green iguanas, Iguana iguana, with metabolic bone disease. Bul Assoc Rept Amphib Vet 3(1):5, 1993.
6. Crane S, Curtis M, Jacobsen ER, et al: Neutralization bone plating repair of a fractured humerus in an Aldabra tortoise. J Am Vet Med Assoc 177(9):945-948, 1980.
7. Robinson Pt, Sedgwick CJ, Meier JE, et al: Internal fixation of a humerus fracture in a Komodo dragon lizard. VM SAC 73(5):645-649, 1978.
8. Redisch RI: Management of leg fractures in the iguana. VM SAC 72(9):1487, 1977.
9. Wallach JD, Boever WJ: Diseases of Exotic Animals. Philadelphia, PA, Saunders, 1983, pp 1027-1043.
10. Jenkins JR: A coaptive device for repair of fractures in the Iguana. J Sm Exotic Anim Med 1(4): 154-155, 1992.
11. Cooper JE, Jackson OF: Diseases of the Reptilia. London, UK, Academic Press, 1981, pp 542-549.
12. Hartman RA: Use of an intramedullary pin in repair of a midshaft humeral fracture in a green iguana. VM SAC 71(11):1634-1635, 1976.
13. Kuehn G: Bilateral transverse mandibular fractures in a turtle. Proc Am Assoc Zoo Vet, 1973, p 243.
14. Redisch RI: Repair of a fractured femur in an iguana. VM SAC 73(12):1547-1548, 1978.
15. Egger EL: External skeletal fixation - general principles, in Slatter D (ed): Textbook of Small Animal Surgery, vol 2 (ed 2). Philadelphia, PA, Saunders, 1993, pp 1641-1656.
16. Weigel JP: Amputations, in Slatter D (ed): Textbook of Small Animal Surgery, vol 2 (ed 2). Philadelphia, PA, Saunders, 1993, pp 1901-1910.
17. Bennett RA: Reptilian surgery - Part II. Management of surgical diseases. Comp Cont Ed Pract Vet 11(2):122-133, 1989.
18. Lutz ME: Surgical and conservative tail repair in iguanas. J Sm Ex Anim Med 1(3):128-129, 1992.
Bone plating often requires a relatively large patient; however, with the recent availability of the veterinary cuttable plates (Synthes, Paoli, PA) with screws as small as 1.5 mm diameter (1.1 mm core diameter) bones as small as 3 mm diameter may be plated. Finger plates are also applicable to many long bone fractures in reptiles. Bone plating is often the treatment of choice for stabilizing femur and humerus fractures in chelonians. In some reptiles, especially varanids, long bones are curved. In large patients, 2.7 mm reconstruction plates may be used to allow the plate to be contoured to such bones. Of course, bone plating is expensive and requires specific expertise.
In most cases, removal of bone plates is not recommended. With IM pins or ESF, the decision to remove implants should be based on radiographic evidence of bone healing. In some cases, a fibrous union may provide adequate stability allowing fracture healing to proceed to completion if the implants fail or must be removed prior to the development of radiographic union.
Limb Amputation - Phalanges or an entire digit may be amputated with good cosmetic result. When a digit is to be amputated, the incision should be planned to allow the skin closure to be flush with the metacarpal or metatarsal portion of the foot creating a stumpless, cosmetic, functional appendage. Two skin flaps are created with the plantar/palmar flap being longer than the dorsal. When the two flaps are brought together in apposition the incision will be elevated from the substrate making it less likely to become severely contaminated or traumatized by the substrate.
In most animals where limb amputation is indicated, it is recommended that amputation be performed as proximal as possible to prevent the patient from traumatizing the stump on its substrate. This technique has also been recommended for reptiles; however most reptiles have very tough skin which is resistant to such trauma. Their scar tissue, however, is more delicate and easily abraded. Further, because most lizards stand flat or low to the ground even a short stump may aid in locomotion. When a limb must be amputated in a lizard, if the patient may benefit from the ability to use the stump it may be amputated in a location which will provide a stump that will aid in ambulation. The skin should be incised to create a flap on the ventral surface which will be placed over the end of the stump and sutured dorsally (fig. 4). This will place healthy, normal skin in contact with the substrate and the incision/scar tissue dorsal and lateral. The end of the bone should be padded with viable soft tissues prior to skin closure.
In many cases, because of the nature of the trauma or the presence of infection along fascial planes, the entire limb must be removed. This is best performed at the scapulo humeral or the coxofemoral joint. Muscles should be transected at their distal insertions to allow for adequate soft tissue coverage of the site. The muscle bellies are then elevated from the periosteum proximally until the articulation is exposed. Smooth transection of the nerves with a scalpel is recommended.16 The nerves may be injected with bupivicaine to provide local anesthesia minimizing postoperative pain.
In chelonians it is usually best to amputate as proximal as possible since they stand more upright and are more likely to traumatize their stump. A prosthesis may be provided by securing a wood block, furniture coaster, or wheel on the plastron ventral to the shoulder or hip joint secured using an acrylic cement. This will elevate the affected corner of the shell allowing easier ambulation using the remaining limbs.
In most reptiles, a tail that has been traumatized may be amputated back to healthy tissue, especially when vertebrae are exposed. Many lizards and some snakes seem able to voluntarily break off their tail by a process called autotomy in an effort to escape from a predator. They have the ability to regenerate the lost portion of their tail.17 The regenerated segment contains a cartilaginous rod and a different scale and color pattern. Primary closure of the exposed end will prevent regeneration. In handling these species, care must be taken to avoid autotomy. In some instances only a partial autotomy occurs. The distal segment may retain it vascular integrity allowing the defect to heal with a better cosmetic result. A padded tubular splint should be applied to prevent progression of the defect during tail movement.2,3,18
REFERENCES
1. Marcus LC: Veterinary Biology and Medicine of Captive Amphibians and Reptiles. Philadelphia, PA, Lea & Febiger, 1981, pp 77-79.
2. Frye FL: Biomedical and Surgical Aspects of Captive Reptile Husbandry. Edwardsville, KS, Veterinary Medicine Publishing Co, 1981, pp 247-278.
3. Frye FL: Biomedical and Surgical Aspects of Captive Reptile Husbandry (ed 2). Malabar, FL, Krieger Publishing Co, 1991, pp 461-465.
4. Burgmann PM, McFarlen J, Thiesenhausen K: Causes of hypocalcemia and metabolic bone disease in Iguana iguana. J Sm Ex Anim Med 2(2):63-68, 1993.
5. Mader DR: Use of calcitonin in green iguanas, Iguana iguana, with metabolic bone disease. Bul Assoc Rept Amphib Vet 3(1):5, 1993.
6. Crane S, Curtis M, Jacobsen ER, et al: Neutralization bone plating repair of a fractured humerus in an Aldabra tortoise. J Am Vet Med Assoc 177(9):945-948, 1980.
7. Robinson Pt, Sedgwick CJ, Meier JE, et al: Internal fixation of a humerus fracture in a Komodo dragon lizard. VM SAC 73(5):645-649, 1978.
8. Redisch RI: Management of leg fractures in the iguana. VM SAC 72(9):1487, 1977.
9. Wallach JD, Boever WJ: Diseases of Exotic Animals. Philadelphia, PA, Saunders, 1983, pp 1027-1043.
10. Jenkins JR: A coaptive device for repair of fractures in the Iguana. J Sm Exotic Anim Med 1(4): 154-155, 1992.
11. Cooper JE, Jackson OF: Diseases of the Reptilia. London, UK, Academic Press, 1981, pp 542-549.
12. Hartman RA: Use of an intramedullary pin in repair of a midshaft humeral fracture in a green iguana. VM SAC 71(11):1634-1635, 1976.
13. Kuehn G: Bilateral transverse mandibular fractures in a turtle. Proc Am Assoc Zoo Vet, 1973, p 243.
14. Redisch RI: Repair of a fractured femur in an iguana. VM SAC 73(12):1547-1548, 1978.
15. Egger EL: External skeletal fixation - general principles, in Slatter D (ed): Textbook of Small Animal Surgery, vol 2 (ed 2). Philadelphia, PA, Saunders, 1993, pp 1641-1656.
16. Weigel JP: Amputations, in Slatter D (ed): Textbook of Small Animal Surgery, vol 2 (ed 2). Philadelphia, PA, Saunders, 1993, pp 1901-1910.
17. Bennett RA: Reptilian surgery - Part II. Management of surgical diseases. Comp Cont Ed Pract Vet 11(2):122-133, 1989.
18. Lutz ME: Surgical and conservative tail repair in iguanas. J Sm Ex Anim Med 1(3):128-129, 1992.
Posté par Kuzanaguy
Mince en faite j ai mal lu un passage,j avais cru voir des données sur la resistance osseuse des reptile=mais en faite on ne parle que de traitement sur des reptile captifs au niveau femorale ou mandibulaire................et aussi des prothèse orthopedique.la mineralisation et blablabla.................................mes désolé vari je retourne a mes recherches.
Posté par Pyroraptor
c'est pas grave mais les modos vont avoir du boulot
Posté par Kuzanaguy
Pourquoi?ce doc est tres interessant tout de mème et il peu etre importé sur science de la vie!
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