Surgery: principles and techniques

image of Surgery: principles and techniques
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There are specific anatomical considerations, as well as unique aspects of patient preparation, positioning and equipment, with which the reptile clinician should be familiar. This chapter considers the most important factors and frequently performed procedures, covering equipment, patient preparation, soft-tissue and orthopaedic procedures, intra- and postoperative care.

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13.3 A selection of small and microsurgical instruments commonly used in exotic animal surgery: (a) straight microscissors with round handle and counterbalanced; (b) micro needle holders with round handle and counterbalanced; (c) curved microforceps with platform tips and round handle and counterbalanced; (d) straight microforceps with 2 mm ring tips and round handle and counterbalanced. (© SJ Divers)
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13.4 The Lonestar retractor incorporates an adjustable plastic ring to which elastic stays with hooks are attached. This retractor is extremely versatile and works well with a variety of species and surgical procedures. (© SJ Divers)
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13.5 Surgical saws: (a) Stryker 4200 Cordless Driver 2; (b) oscillating sagittal saw attachment to the air-powered 3M mini-driver. (a, Courtesy of Stryker Instruments Inc.; b, © SJ Divers)
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13.6 Orthopaedic implants. (a) FESSA bar with four mini-IMEX pins secured using low-profile screws. (b) Small locking plate and screw. The screw thread (red arrow) engages the plate (white arrow) as shown in the inset, thereby preventing compression of the bone to the plate. Alternatively the screw could be inserted through the adjacent aperture (black arrow) to create compression between the plate and bone. (© SJ Divers)
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13.7 Headband-mounted X2.5 magnification loupe with integrated light source. (© SJ Divers)
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13.8 Video-telescope-operating microscopy. The operating telescope (1) with camera (2) and light cable (3) attached, and supported above the surgical site by a mechanical arm (4), provides a large magnified image on the endoscopy monitor (inset). (© SJ Divers)
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13.9 (a) Medium vascular clip cartridge containing 10 clips and an applicator (Hemoclips, Weck). (b) Four different available sizes of vascular clips. (© SJ Divers)
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13.10 Radiosurgery equipment: (a) the 4.0 MHz Surgitron dual-frequency radiosurgery base unit; (b) bipolar forceps; (c) monopolar cutting electrode. (Courtesy of Ellman International Inc.)
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13.12 The Bair Hugger is a forced-air heating system for maintaining patient temperature. (a) The heat unit (1) is positioned under or adjacent to the table, and is (b) connected to an air blanket (2) under this lizard. (© SJ Divers)
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13.13 Patient positioning: (a) a large tortoise held in lateral recumbency using a V-trough operating table; (b) a large anaconda supported using multiple tables. (© SJ Divers)
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13.14 This kingsnake has been positioned on a forced-air heating blanket, and a sterile adhesive drape has been applied. Note the focused illumination of the surgical site. (© SJ Divers)
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13.15 Routine coeliotomy skin closure in a green iguana using monofilament nylon in an everting horizontal mattress pattern. Inset – open surgical wound following abscess removal in a giant day gecko; note the inverting wound edges. (© SJ Divers)
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13.16 Biluminal central line placement in the left jugular of a leopard tortoise. In all images, the head is positioned at the bottom of the image with the cranial rim of the carapace to the left and cranial plastron to the right. (a) Following a surgical cut-down procedure to identify the vessel, a 20 G intravenous catheter has been temporarily placed into the jugular. (b) The catheter-pack sterile wire (arrowed) has been threaded through the intravenous catheter and advanced into the vein. (c) While the position of the wire (red arrow) is maintained, the intravenous catheter is removed and replaced by a dilator (white arrow), which slightly enlarges the opening in the vein. (d) While maintaining the wire in place, the dilator is removed and the silicone central catheter (arrowed) is threaded over the wire, and into the vein. The wire is then removed, and the catheter flushed and capped. (e) A blue plastic support is placed over the catheter close to the insertion point, and used to secure the catheter to the skin using sutures. (f) The catheter is additionally secured to the head using sutures, and finally the two ports are taped to the cranial carapace. The catheter insertion site is covered with a transparent adhesive dressing. (© SJ Divers)
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13.17 Infected rodent-induced trauma in a boa constrictor: (a) at initial presentation, demonstrating severe muscle loss, exposure of multiple vertebrae, necrosis and infection; (b) after surgical debridement and 9 weeks of weekly dressings (note the healthy granulation tissue); (c) after 10 months of wound care. Despite the profound improvement, this snake may have long-term dysecdysis issues associated with this scar. (© SJ Divers)
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13.18 Plastron shell infection in a spur-thighed tortoise: (a) surgical debridement of the lesion using a curette; (b) irrigation and cleaning using cotton-tipped applicator and dilute povidone iodine; (c) antibiotic ointment applied to the wound; (d) bandage technique to maintain medication in contact with plastron and prevent contamination of the area; (e) healthy granulation tissue 4 weeks later. (© SJ Divers)
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13.19 A wet-to-dry dressing has been applied to an infected carapacial fracture in this small tortoise. Openings have been cut to permit the unhindered use of the head and limbs. (© SJ Divers)
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13.20 Severe trauma management in a Burmese python. (a) Necrotic and infected wound on initial presentation being irrigated with sterile saline. (b) Wet sterile gauze overlaid with dry sterile gauze on the wound. Note the loops of sutures that have been placed around the entire wound in preparation for the tie-in. (c) The ties have been laced through the suture loops to hold the dressing in place. (© SJ Divers)
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13.21 Aural abscess removal in a spur-thighed tortoise. (a) The caseous plug is being gently levered out of the tympanic cavity using forceps and an angled curette. (b) The removed abscess; note the projection that was within the Eustachian tube (arrowed). (c) A cotton-tipped applicator has been inserted down the Eustachian tube to ensure patency. (© SJ Divers)
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13.22 Thyroid adenoma in a green iguana: (a) surgical exposure of the mass at the coelomic inlet; (b) the removed bilobed gland has been transected to reveal the cystic nature of the mass. (© SJ Divers)
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13.23 Focal corneal infection in a Hermann’s tortoise: (a) initial presentation of a focal accumulation of bacteria and leucocytes on the cornea; (b) following corneal debridement, further treatment includes topical antimicrobial therapy and, if deemed necessary, a third eyelid flap procedure. (© SJ Divers)
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13.24 Subspectacular abscess treatment in a Burmese python. (a) Initial presentation with distension of the subspectacular space and neovascularization of the spectacle. The recommended 90-degree wedge resection in the most dependent aspect of the spectacle is indicated (blue dotted line). (b) Intraoperative view following wedge resection and flushing. Note that the cornea is now visible and exposed. (c) View of the opening to the lacrimal duct (arrowed) that has been catheterized for retrograde flushing. (© SJ Divers)
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13.25 Enucleation in a green iguana: (a) original presentation of panophthalmitis; (b) collapse of the globe following enucleation and tarsorrhaphy. (© SJ Divers)
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13.26 Phallus amputation in a snapping turtle: (a) prolapsed phallus clamped, and mattress sutures placed along the base in preparation for removal; (b) view of the vent immediately following amputation, with the small stump retracted into the cranioventral cloaca. (© SJ Divers)
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13.27 Cloacal prolapse: (a) presentation of cloacal prolapse in a green iguana; (b) cleaning a cloacocolonic prolapse in a spur-thighed tortoise in preparation for surgical replacement. (© SJ Divers)
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13.28 Transcutaneous cloacopexy in a green iguana. (a) Following replacement of the viable prolapsed tissue and aseptic skin preparation of the caudolateral coelom, a large lubricated cotton-tipped applicator is inserted into the cloaca, and tented against the ventrolateral body wall. Two to three simple interrupted polydioxanone sutures are placed through the skin and cotton-tip. (b) The suture ends are left long and held by haemostats. The cotton-tipped applicator, carrying the sutures, is removed from the cloaca. The cotton is teased away from the sutures (inset). (c) After pulling the sutures back into the cloaca with the haemostats, they are tied (arrowed). The cloacocolonic wall is now sutured to the body wall and a fibrous adhesion generally develops over the next 4–8 weeks. (© SJ Divers)
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13.30 Transplastron coeliotomy in chelonians. View of the ventrum of a generic chelonian illustrating the positions of the clavicles (1), cranial rim of the pelvis (2), heart (3) and paired abdominal veins (arrowheads). The approximate locations of plastron hinges in spp. (green line) and spp. (blue line) are also shown. The four proposed osteotomy incisions are indicated (black dotted lines). (© SJ Divers)
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13.31 Transplastron coeliotomy in chelonians: (a) using an air-powered oscillating saw to cut through the plastron; (b) the plastron flap is elevated and the muscle attachments dissected free. (© SJ Divers)
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13.32 Transplastron coeliotomy in chelonians: (a) midline incision between the abdominal veins (arrowed); (b) ring retractor and elastic stays improve access as a liver biopsy is performed. (© SJ Divers)
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13.33 Transplastron coeliotomy in chelonians: (a) routine closure of the coelomic membrane using absorbable sutures in a simple continuous pattern; (b) absorbable suture placed through predrilled holes in the plastron flap and shell in preparation for flap reposition; (c) application of low-temperature polymethyl methacrylate (Technovite) by syringe. (© SJ Divers)
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13.34 Transplastron coeliotomy in chelonians. (a) Final repair with the incision and sutures buried beneath the repair material. (b) View of the plastron of a spur-thighed tortoise that underwent transplastron coeliotomy 12 weeks earlier. The plastron flap had become a sequestrum and, following removal,  new bone can be seen filling the entire area. It is recommended to leave this sequestrum flap in place for 6–12 months to provide additional protection. (© SJ Divers)
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13.35 Prefemoral coeliotomy in a red-eared terrapin in dorsal recumbency: (a) following prefemoral skin incision, a ring retractor and elastic stays have been placed, and the coelomic musculature can be seen; (b) following blunt dissection through the musculature, part of the left ovary can be seen; (c) following the intracoelomic procedure, the musculature is closed using a continuous pattern; (d) finally, the skin is closed in a routine manner. (© SJ Divers)
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13.36 Left paramedian coeliotomy in a chameleon. (a) With the lizard in right lateral recumbency, the proposed surgical approach is indicated (blue dotted line). (b) Several ribs and associated intercostal vessels can be seen (arrowheads), as radiosurgical dissection continues along the ventral border of the ribcage. (c) The ribcage is reflected dorsad (1), and oviducts containing eggs (2) can be exteriorized. The finger-like projections of the caudal avascular lung can also be seen and must be preserved (3). (d) Routine closure of the muscle and skin incisions. (© SJ Divers)
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13.37 Coeliotomy in the green iguana. (a) Ventrum of an iguana illustrating the paired pelvic veins (1), anastomosing to form the large abdominal vein (2). Possible coeliotomy entry can be made using a paramedian (blue dotted line) or midline (black dotted line) incision. (b) Paramedian skin incision made using a reversed guarded scalpel blade to avoid inadvertent damage to deeper structures. (c) Dissection through the thin abdominal musculature using cotton-tipped applicators. (d) Exposure of the coelom and visualization of the ventral midline abdominal vein (arrowed). (© SJ Divers)
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13.38 Coeliotomy in a green anaconda. (a) Initial skin incision can be made between the first and second (blue dotted line) or second and third (green dotted line) rows of lateral scales. Incision through the large ventral scutes or between the large ventral scutes and the first row of lateral scales (red dotted line) is not advised. (b) Subcutaneous dissection to gain access to the coelom. (© SJ Divers)
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13.39 Coeliotomy in snakes. (a) Entry into the coelom just ventral to the ribs to permit exteriorization of a large mass, with a ring retractor used to improve visualization (corn snake). (b) Closure of the coelomic musculature using absorbable poliglecaprone 25 suture material in a continuous pattern (kingsnake). (c) Routine skin closure using nylon sutures in an everting horizontal mattress pattern. Note the marked tape adjacent to this Kenyan sand boa that helped indicated the required approach. (© SJ Divers)
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13.40 Orchidectomy in the green iguana: (a) elevation of the left testis (1) with vascular clips applied to the mesorchium (arrowed); the colon (2) is also visible; (b) following resection of the testis, the vascular clips (arrowed) can be seen resting on the renal vein. (© SJ Divers)
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13.41 Oophorectomy in the green iguana. (a) Elevated right ovary (inactive) (1) revealing the ovarian ligament and associated vessels that have been ligated with vascular clips (arrowed). Below the clips, the renal vein (2) and left adrenal gland (3) can be seen. (b) Exteriorized active ovaries owing to preovulatory follicular stasis. Note the massive enlargement of both ovaries and the mesovarian vessels (arrowed). (© SJ Divers)
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13.42 Oophorectomy in chelonians. (a) Transplastron oophorectomy in a box turtle. Both left (1) and right (2) ovaries have been exteriorized, with a haemostat clamped on the right mesovarium (3) and a vascular clip applied (arrowed). Note the muscle attachments to the caudal margin of the plastron flap (4). (b) Left prefemoral coeliotomy in a red-eared terrapin. The left ovary (1) has been exteriorized and the mesovarium clamped using a haemostat (2). Following vascular clip ligation of the major vessels, the mesovarium is transected using bipolar radiosurgery (3). (© SJ Divers)
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13.43 Salpingectomy in lizards and chelonians. (a) Exposure of both oviducts containing eggs in a green iguana. Inset – the ovaries are anatomically separate from the oviducts and involuted; however, it is critical that they are removed following salpingectomy. (b) Exteriorization of an oviduct containing eggs following a transplastron coeliotomy in an African spurred tortoise. A vascular clip (arrowed) has been applied to ligate several vessels, and the mesovarium is being dissected using a 980 nm diode laser. (© SJ Divers)
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13.44 Reproductive surgery in an endangered Guatemalan beaded lizard. (a) A retained egg is obvious within the exteriorized oviduct. The proposed salpingotomy incision in order to remove the egg is indicated (white dotted line). The incision is subsequently closed using fine absorbable suture material. (b) Ovocentesis in the same lizard to resolve preovulatory follicular stasis but retain reproductive capability. (© SJ Divers)
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13.45 Salpingotomy in snakes. (a) Following coeliotomy in this endangered indigo snake, an egg retained within the oviduct has been exteriorized. The proposed salpingotomy incision is indicated (black dotted line). (b) Following egg removal in this corn snake, the thinly walled oviduct is closed using fine suture material. (© SJ Divers)
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13.46 (a) Removal of an ectopic mummified fetus (1) from between the normal right (2) and left (3) oviducts in a green anaconda. (b) The complete fetus following removal. (© SJ Divers)
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13.47 Salpingectomy in snakes. (a) In this timber rattlesnake, severe bacterial salpingitis necessitated major surgical exposure and salpingectomy. (b) In this corn snake, a granulosa cell tumour involving the oviduct required ovariosalpingectomy. (© SJ Divers)
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13.48 Cystotomy and urolith removal in a desert tortoise: (a) elevation of the urolith within the thinly walled bladder; (b) packing the coelom with moistened sterile gauze is recommended as bladder contents are seldom sterile in chelonians; (c) stay sutures are placed at either end of the cystotomy incision to help keep the bladder elevated and to assist with closure; (d) following the removal of the urolith, the stay sutures are elevated and assist with two-layer closure of the thinly walled bladder. (© SJ Divers)
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13.49 Oesophagostomy tube placement in chelonians. (a) The positions of the left dorsolateral jugular vein (blue dotted line) and ventrolateral carotid artery (red dotted line) are shown, and avoided by the haemostat jaws (arrowed) exiting the caudolateral neck in this spur-thighed tortoise. (b) The correct placement of the tube is verified using endoscopy in this soft-shelled turtle. Inset – intraluminal view of the red rubber feeding tube. (c) The tube is secured using a Chinese finger-trap suture in this soft-shelled turtle. (d) The capped tube is also attached to the carapace, usually with tape, but in aquatic soft-shelled turtles, sutures can be used. (© SJ Divers)
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13.50 Enterotomy in a bearded dragon with intestinal foreign body and partial obstruction unresponsive to medical therapy. (a) The exteriorized intestinal viscus is isolated using atraumatic paediatric bowel clamps and sterile gauze. (b) Craniocaudal enterotomy incision permits the removal of the foreign body and associated digesta. Note that both the serosa (1) and mucosa (2) are clearly visible. (c) Following removal of the contaminated material and gauze, and using clean instruments, the mucosa is closed using absorbable antibiotic-impregnated (triclosan) poliglecaprone 25 suture material in a simple interrupted pattern. (d) The serosal layer is closed using a simple continuous pattern. Alternatively, a single-layer closure is also acceptable. The intestinal tract and entire coelom are flushed with sterile saline before routine coeliotomy closure. (© SJ Divers)
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13.51 Coeliotomy and renal biopsy in a kingsnake. (a) Coeliotomy approach and a ring retractor to improve visualization. (b) Intraoperative view of the kidney following renal biopsy (arrowed). Inset – excised renal biopsy sample. (© SJ Divers)
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13.52 Coeliotomy and liver biopsy (guillotine method) in a small bearded dragon: (a) intraoperative view of the coelom and placement of a suture loop over the caudal aspect of the left liver lobe; (b) the suture is tightened, taking care not to cut through the tissue, and the distal tissue is sharply dissected free. (© SJ Divers)
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13.53 Distal tail amputation in a green iguana. (a) Presented tail with distal avascular necrosis. The margin between visibly normal and abnormal tissue is marked (arrowed). (b) Following aseptic preparation, the tail is amputated by snapping and twisting the caudal tail cranial to the beginning of the necrosis (arrowed) to ensure that all diseased tissue is removed. The muscle strands of the proximal tail have been trimmed. (© SJ Divers)
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13.54 Proximal tail amputation in a green iguana. (a) Incising the dorsal skin of the proximal tail using a CO laser. (b) The surgical dissection continues through the tail musculature and vertebra, ensuring that a large ventral skin flap is preserved. (c) This ventral flap is lifted over the exposed musculature and spine and sutured to the dorsal skin margin using simple interrupted sutures. (© SJ Divers)
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13.55 Digit amputation in a Bosc monitor. (a) Preoperative view of the left forelimb illustrating the planned incision (red line) between the scales at the proximal base of digit two (arrowed). (b) Following amputation, two mattress sutures close the defect (arrowed), and any excess skin is trimmed. (© SJ Divers)
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13.56 Forelimb amputation in a green iguana. (a) Initial skin incision creates a large dorsolateral skin flap that is reflected to reveal the triceps (1) and brachialis (2) muscles. (b) The musculature is transected, the humerus disarticulated and the limb removed, taking care to ligate the major vessels and nerves (arrowed). (c) The transected muscle bellies of the triceps (1), biceps (2) and coracobrachialis (3) are sutured over the exposed glenoid fossa (4). (d) The lateral skin flap is sutured over the defect using horizontal mattress sutures, and any excess skin is trimmed and discarded. (© SJ Divers)
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13.57 External coaptation for fracture repairs in lizards. (a) Closed ulnar fracture in a Yemen chameleon immobilized by strapping the forelimb to the lateral body wall. Note the wooden splint (arrowed) that prevents bending of the fracture site. (b) Femoral fracture in a bearded dragon immobilized using a thermal plastic splint (arrowed) moulded to the caudal pelvic limb and tail base, and secured using adhesive tape. The splint prevents movement of the coxofemoral joint, which is essential for immobilization of the femoral fracture site. (c) Right femoral and right pelvic fractures in a green iguana immobilized using a Hexcelite cast that extends from the right tarsus to the left stifle. This splint immobilizes the pelvis and both the right stifle and coxofemoral joints. (© SJ Divers)
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13.58 Internal fixation in an alligator: (a) radiograph of the right pelvic limb demonstrating fractures of the tibia, fibula and the metatarsal of digit five; (b) intraoperative view of the placement of a locking bone plate on to the tibia; (c) postoperative radiograph demonstrating adequate reduction of the tibial and fibular fractures. (© SJ Divers)
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13.59 Mandibular fracture (red arrows) repair in a snapping turtle: (a) multiple positive-profile pins are placed into the mandible; (b) the ends of the pins are bent along the long axis of the mandible to add strength to the external fixator; (c) acrylic material has been placed over the pins to complete the rigid external fixation (yellow arrow). Note the placement of an oesophagostomy tube (white arrow) to facilitate nutritional support during healing. (© SJ Divers)
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13.60 Vacuum-assisted wound closure in an aquatic turtle with severe shell necrosis and infection. (a) The necrotic and infected carapace is resected using a rotary saw. (b) Additional debridement of the underlying soft tissues is performed. (c) A non-adherent mesh wound covering is applied, followed by the first layer of sterile open-cell foam (1), a fenestrated sterile tube (arrowed), and the second layer of foam (2); an occlusive adhesive drape covers the wound and incorporates the surrounding normal shell to ensure an air-tight seal. (d) The wound drainage tube is connected to a vacuum line (arrowed), and once negative pressure is applied the foam collapses as shown. (© SJ Divers)
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13.61 Fractured-shell repairs in chelonians. (a) A T-plate and screws have been used to stabilize the comminuted plastron fracture (red dotted line) in this aquatic turtle. Note the porcine small intestinal submucosal graft (Biosist) (arrowed) that has been used to fill a defect. (b) Screws and cerclage wire have been used to repair the carapacial fracture (red dotted line) in this box turtle. (© SJ Divers)
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13.62 Cable-tie fracture repair in an aquatic turtle. (a) Aquatic turtle with a simple fracture of the caudolateral carapace (red dotted line) that has been repaired using cable ties and plastic bases. (b) Close-up view illustrating the position of the plastic bases (1) across the fracture site (red dotted line). One cable tie (2) has been placed through both bases and secured using the base of a second cable tie (3). (© SJ Divers)
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13.63 Stifle luxation and cranial cruciate repair in a spur-thighed tortoise. (a) Arthrotomy incision to expose the stifle joint for removal of the cruciate remnant and flushing of the joint. (b) Incision along the cranial aspect of the lateral vastus muscle (red dotted line) to create an autograft. (c) Elevation of the lateral vastus graft from its proximal origin (white arrow) but remaining attached to its insertion at the tibial tuberosity (black arrow). A small cruciate hook has been passed through the intercondylar space of the joint. (d) The graft, drawn through the joint space, is held over the lateral femoral condyle (arrowed). (e) The autograft is sutured to the periosteum on the lateral surface of the lateral femoral condyle using four simple interrupted absorbable monofilament polydioxanone sutures (arrowed). (f) Closure of the joint capsule with lateral imbrication (blue dotted line) to improve joint stability. Closure of the superficial fascia and skin were routine. (© SJ Divers)
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13.64 Surgical implantation of antibiotic-impregnated polymethyl methacrylate (AIPMMA) beads in a tortoise with proximal tibial osteomyelitis: (a) curette debridement of the caseous lesion from the proximal tibia; (b) further debridement using an orthopaedic burr to ensure removal of all necrotic and infected material; (c) placement of a single AIPMMA bead (arrowed) into the tibial defect; (d) routine closure of the subcutaneous fascia and skin. (© SJ Divers)
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13.65 Postoperative care of reptiles. (a) A bearded dragon following coeliotomy. This abnormal posture, believed to be associated with ventral coeliotomy pain, resolved shortly after the administration of analgesics. (b) Localized dysecdysis around the suture line is to be expected and will resolve upon suture removal. (c) Infected coeliotomy wound in a green iguana. In this case, postoperative hygiene was poor and wound infection necessitated a second procedure 1 week after the initial surgery. Thanks to improvements in hygiene, the iguana recovered uneventfully. (© SJ Divers)
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