A novel surgical technique for enucleation in rabbits to reduce the risk of intra- and post-operative orbital hemorrhage.

A 10-year-old male castrated Holland Lop rabbit (Oryctolagus cuniculus) was presented for severe ulcerative stromal keratitis of the right eye and a luxated hypermature cataract and glaucoma of the left eye. Staged bilateral enucleation was elected. A LigaSure™ electrosurgical bipolar vessel-sealing device was used as a means to minimize intraoperative and post-operative hemorrhage, especially that associated with the orbital venous plexus. The LigaSure™ was used to ligate and transect all extraocular muscles, the optic nerve bundle, and the base of the third eyelid with no complications encountered. Overall, the LigaSure™ was easy to use, resulted in minimal hemorrhage, and reduced surgery time. This is the first report of the use of a LigaSure™ to aid in the enucleation of a rabbit. Although only positive results were achieved as an alternative to conventional methodologies, its use in clinical practice should be that of caution until a larger study evaluating the long-term results is performed.

Pain and analgesia in pet rabbits within the veterinary environment: a review.

OBJECTIVE: To provide an overview of pain and analgesia in rabbits with the aim of developing a more accurate understanding of these topics. To illustrate and discuss the areas that have advanced in recent years and those that still require further research. DATABASES USED: Three key subject resources were used: Web of Science, Medline and CAB Abstracts. Search terms were rabbits, lagomorphs, laboratory animals, pet, pain, surgical procedures, ovariohysterectomy, orchiectomy, castration, analgesia, opioids, and non-steroidal anti-inflammatory drugs. References from books and articles relevant to the topics were also included. CONCLUSIONS: Rabbit medicine has improved over the last 20 years, but the literature suggests that pain management in this species is still inadequate and veterinary professionals believe their knowledge of pain and analgesia in this species is limited. Assessment and quantification of pain in rabbits can be challenging in a clinical environment not only because, as a prey species, rabbits tend to hide signs of pain but also because there are no validated methods to assess pain, except the Rabbit Grimace Scale, which is based on only one rabbit breed. Current consensus is that perioperative multimodal analgesia is the best practice. However, it is not widely used in rabbits. In rabbits, analgesia protocols and dosages reported in the literature are often poorly researched and do not result in complete pain amelioration with the return of normal. The present literature on rabbit pain and analgesia presents gaps either due to unexplored areas or insufficient findings. Further research should focus on these areas with the aim of improving the welfare of rabbits within a veterinary clinic.

Four cases of iridociliary tumors in domestic rabbits (Oryctolagus Cuniculus).

Spontaneously occurring ocular neoplasia is rarely reported in rabbits. This case series presents four cases of rabbits diagnosed with iridociliary tumors, which have not been previously reported in this species. Major pathological findings include epithelial tumors affecting the anterior uvea with variable pigmentation and basement membrane formation. Follow-up information was only available for two cases, but neither showed evidence of metastasis, suggesting that the prognosis for these tumors in rabbits, as in other species, may be very good.

Arthroscopic approach and anatomy of the stifle joint in the rabbit.

OBJECTIVE: To describe a technique and normal findings for arthroscopy of the stifle in rabbits. STUDY DESIGN: Cadaver study. ANIMALS: Twenty cadaveric stifles from New Zealand White rabbits were examined. METHODS: The arthroscope was placed through a medial portal, and instrument portals were created on the lateral aspect of the joint. The same portals were used for examination of the entire joint and palpation of structures with a probe. RESULTS: Structures identified in the proximal aspect of the stifle included the suprapatellar pouch, suprapatella, patella, medial and lateral proximal recesses, medial and lateral trochlear ridges, trochlear groove. Structures identified in the distal aspect of the joint included the cranial and caudal cruciate ligaments, medial and lateral menisci, medial and lateral femoral condyles, the long digital extensor tendon, and the cranial meniscal ligaments were identified. All of the proximal structures could be seen in 16/20 limbs. Distally, the cranial cruciate ligament could be identified and manipulated most often (17/20 limbs), followed by the caudal cruciate ligament (11/20), the menisci (9/20), and condyles (9/20). The average examination time was 27 minutes. There was a variably present femorotibial membrane. CONCLUSION: We conclude that the arthoscopic evaluation of the stifle in rabbits is a viable surgical approach and could be used for rabbit models or to examine clinical cases with stifle pathology. Precise portal placement and adequate infrapatellar fat pad debridement were critical for success.

Rabbit Neutering in Primary-Care Education: Insights from a Surgical Clinic.

Involvement in canine and feline surgical neutering clinics is generally considered to be a key element of primary-care veterinary education, yet opportunities for veterinary students to develop their surgical skills with rabbit patients are uncommon. This is despite the fact that rabbits are currently estimated to be the third most popular companion animal species and the fact that the British Small Animal Veterinary Association (BSAVA) recommends that all non-breeding rabbits be neutered soon after they attain sexual maturity. We describe a pilot rabbit-neutering clinic designed to provide high-quality care for rabbit patients while offering opportunities for undergraduate surgical and case-management skills development. We report on the clinical outcomes for patients. Rates of morbidity (n=18) and mortality (n=1) were low. Of complications reported, the majority (n=16) were considered minor. Challenges included ensuring that staff and students were trained in the specific features of rabbit anesthesia and recovery behavior. We conclude that rabbit surgical clinics offer excellent learning opportunities for undergraduate veterinary students. With prior training in handling and close individual supervision, it is possible to achieve good clinical outcomes and to have a positive impact on the welfare of companion animal populations.

Calculation of posterior chamber intraocular lens (IOL) size and dioptric power for use in pet rabbits undergoing phacoemulsification.

OBJECTIVES: To calculate the size and dioptric power of a posterior chamber intraocular lens (IOL) to achieve emmetropia in adult rabbits and to compare the dioptric power calculation results using a proprietary predictive formula to a retinoscopy-based method. ANIMALS STUDIED: Three wild rabbit cadavers, seven pet rabbits with cataracts and ten healthy pet rabbits. MATERIALS AND METHODS: Implant size was calculated using a capsular tension ring (CTR) (Acrivet® , Berlin, Germany). Published and cadaveric biometric data were used in the predictive formula. An IOL power-escalation study compared the predicted values to the refraction results of one pet rabbit (P1) fitted with a + 41D canine IOL (Acrivet® ) and six pet rabbits (P2-P7) fitted with prototype IOLs (Acrivet® ). Retinoscopy of 10 healthy pet rabbits served as controls. RESULTS: A 13.5 mm CTR fitted in all rabbits and permitted the use of a 13 mm IOL. The predicted IOL power ranged between +24D and +25D. The +41D IOL resulted in a refraction error of +8D. Progressive recalculation through a calibration formula led to the insertion of three +49D IOLs in two pet rabbits and a refraction of +6D to +8D, followed by seven +58D IOLs in four pet rabbits and a refraction median of 0D (range: -1.5D to +1D). CONCLUSIONS: A 13 mm prototype IOL of +58D achieves emmetropia and is of adequate size for rabbits. The combined use of a CTR and retinoscopy is a useful method to calculate the size and refractive power of a new, species-specific, veterinary IOL.

Ventral rhinotomy in a pet rabbit (Oryctolagus cuniculus) with an odontogenic abscess and sub-obstructive rhinitis.

A rabbit was presented for severe dyspnea and was diagnosed with an odontogenic abscess obstructing the rostral nasopharynx using CT scan and oral endoscopy. The offending tooth was extracted intraorally, but due to persistent dyspnea, an endoscopic-guided ventral rhinotomy was performed. The dyspnea subsequently resolved, but the rabbit died 5 weeks later from a seemingly unrelated cause.

Rhinotomie ventrale chez un lapin de compagnie(Oryctolagus cuniculus)atteint d'un abcès odontogène et d'une rhinite causant une subocclusion. Un lapin a été présenté pour une dyspnée grave et a été diagnostiqué avec un abcès odontogène bloquant le nasopharynx rostral par tomodensitométrie et endoscopie orale. La dent en cause a été extraite intra-oralement, mais, en raison d'une dyspnée persistante, une rhinotomie ventrale guidée par endoscopie a été réalisée. La dyspnée s'est subséquemment résorbée, mais le lapin est mort 5 semaines plus tard d'une cause apparemment non reliée.(Traduit par Isabelle Vallières).

Reported analgesic administration to rabbits undergoing experimental surgical procedures.

BACKGROUND: It has become widely accepted that whenever animals are used in scientific procedures, the 3Rs principle of replacement, reduction and refinement described by William Russell and Rex Burch should be adhered to. Animals should be replaced with non-sentient alternatives if possible, the number of animals used should be reduced and experimental procedures should be refined to minimise pain, suffering and distress. Administration of analgesic agents to animals undergoing surgical procedures is a refinement used to alleviate pain. In this study, a structured literature review was carried out to examine current trends in analgesic administration to rabbits undergoing experimental surgical procedures. RESULTS: 128 papers from 51 peer-reviewed journals were selected for inclusion in this review. Reporting administration of systemic analgesia to rabbits in peer-reviewed scientific papers increased significantly from 16% to 50% between 1995-1997 and 2005-2007 (P < 0.001). Papers that reported ethical approval were more likely than papers that did not specify approval to report systemic analgesic administration (P < 0.001). When systemic analgesics were administered, buprenorphine was the most frequently used agent and non-steroidal anti-inflammatory drugs were used less frequently than opioids in both time periods. CONCLUSIONS: Although this review provides evidence that systemic analgesic administration to rabbits undergoing surgical procedures is increasing, rabbits do not always receive analgesia when they undergo experimental surgery. Other practices in rabbit perioperative care that could be improved, highlighted by this survey include: 1) changing the timing of analgesic administration by giving systemic analgesics pre- or perioperatively rather than only postoperatively, 2) using multimodal analgesia when pain is likely to be moderate to severe and 3) increasing the use of non-steroidal anti-inflammatory drugs and use of other techniques such as epidural analgesia particularly for orthopaedic procedures.

Successful outcome of hepatectomy as treatment for liver lobe torsion in four domestic rabbits.

CASE DESCRIPTION: 4 rabbits (1.5 to 6 years old) were evaluated at the Angell Animal Medical Center from June 2007 to March 2009 because of nonspecific clinical signs including anorexia, lethargy, and decreased fecal output. CLINICAL FINDINGS: Physical examination revealed signs of pain in the cranial portion of the abdomen, gas distention of the gastrointestinal tract, and diminished borborygmi. Serum biochemical analyses and CBCs revealed moderately to markedly high alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities and mild to moderate anemia with polychromasia. Abdominal radiographic findings were nonspecific. Three of the 4 rabbits underwent abdominal ultrasonography; abnormalities in shape, size, echogenicity, and blood flow of the liver, indicative of liver lobe torsion, were detected. TREATMENT AND OUTCOME: All 4 rabbits underwent surgery, during which liver lobe torsion was confirmed and the affected liver lobe was resected. Histologic examination of sections of the excised lobe obtained from 3 of the 4 rabbits revealed severe, diffuse, acute to sub-acute hepatic ischemic necrosis. All rabbits recovered from surgery; owners reported that the rabbits were doing well 22 to 43 months after surgery. CLINICAL RELEVANCE: Liver lobe torsions in any species are rarely reported, yet 4 cases of liver lobe torsion in domestic rabbits were treated at 1 referral center in a 2-year period. In rabbits, clinical signs of this condition are nonspecific and results of additional tests, including abdominal ultrasonography and serum biochemical analysis, are necessary for diagnosis. Prompt diagnosis and hepatectomy of the affected lobe are recommended and appear to be associated with an excellent prognosis.

Transcutaneous monitor approximates PaCO(2) but not PaO(2) in anesthetized rabbits.

OBJECTIVE: To compare the accuracy of transcutaneous (tc) to arterial partial pressure of carbon dioxide (PaCO(2) ) and partial pressure of oxygen (PaO(2) ) in anesthetized rabbits. STUDY DESIGN: Prospective, randomized, experimental study. ANIMALS: Eight healthy adult female New Zealand white rabbits weighing 4.05± 0.30 kg. METHODS: Isoflurane anesthetized rabbits received six treatments in random order; PaCO(2) <35, 35-45, and >45 mmHg and PaO(2) < 80, 100-200, >200 mmHg. Arterial and transcutaneous measurements were taken after 15 minutes of stabilization at each condition. Linear regression, correlation and Bland-Altman analysis were performed to compare PtcCO(2) to PaCO(2) and PtcO(2) to PaO(2) . RESULTS: Over a range of measured PaCO(2) values from 21 to 67 mmHg (n=24) mean bias for PtcCO(2) was -1 mmHg and the 95% limits of agreement were -7 to 5 mmHg. The correlation between PtcCO(2) and PaCO(2) was strong with R(2) value of 0.9454. Over the entire range of measured PaO(2) values (46-508 mmHg) mean bias for PtcO(2) was -61 mmHg and the 95% limits of agreement were -226 to 104 mmHg. Correlation was poor with R(2) =0.5969. Comparing PtcO(2) to PaO(2) over a narrower range [PaO(2) < 150 mmHg (n=13)] improved the correlation, with an R(2) value of 0.8518, mean bias of -7 mmHg and 95% limits of agreement from -33 to 19 mmHg. CONCLUSIONS AND CLINICAL RELEVANCE: In healthy anesthetized rabbits, PtcCO(2) closely approximated PaCO(2) . In contrast PtcO(2) underestimated PaO(2) , particularly at high values. The PtcCO(2) sensor may be a useful noninvasive way to assess adequacy of ventilation in anesthetized rabbits.

Simultaneous percutaneous implantation of a microdialysis probe for monitoring perineural concentrations of local anaesthetics during peripheral nerve block in rabbits.

OBJECTIVE: To develop a technique that allows simultaneous percutaneous implantation of both a microdialysis probe and injection catheter in order to monitor the perineural pharmacokinetics of local anaesthetics (LA) after a femoral block. STUDY DESIGN: Prospective experimental study. ANIMALS: Five anaesthetized male New Zealand rabbits with a mean ± SD weight of 3.2 ± 0.2 kg. METHODS: After femoral nerve localization by electrostimulation, an injection catheter and a microdialysis probe were slowly and simultaneously inserted into a cannula left into place in the perineural region. Both were then secured into place, after removal of the cannula. At the end of the experiment, methylene blue was injected to confirm the distance from the femoral nerve during subsequent postmortem anatomical dissection of the injection site. RESULTS: Staining was adequate and the catheter found to be located within 4 mm of the femoral nerve in three out of five rabbits. CONCLUSIONS AND CLINICAL RELEVANCE: This procedure allows direct implantation of a microdialysis probe near the injection site of LA during a femoral nerve block without loosing nerve localization accuracy. This procedure has been used successfully to monitor the regional pharmacokinetics of LA after a peripheral nerve block.

[Squeezing of the spermatic cord using a Pean clamp is not suitable for elimination of testicular function in the rabbit]. / Die Quetschung des Samenstrangs eignet sich beim Kaninchen nicht zur Ausschaltung der Hodenfunktion.

OBJECTIVE: The aim of this study was to evaluate the effect of three different methods for squeezing of the spermatic cord as bloodless castration in rabbits according to the "Burdizzo"-method used for ruminants. MATERIALS AND METHODS: In 18 anaesthetized male rabbits (group 1-3) spermatic cords were squeezed twice using three different methods according to Burdizzo: using a Pean haemostat for 3 minutes (group 1, n=10) or 10 minutes (group 2, n=4) or by use of a Doyen intestine clamp for 3 minutes (group 3, n=4). Seven males serving as controls underwent surgical castration under general anaesthesia. Animals were daily examined until day 7, and on days 14 and 90. Blood samples for testosterone measurement were taken on days 1 and 90. On day 90, all animals of groups 1-3 were surgically neutered and testis examined histologically in comparison with group 4. RESULTS: A swelling of the squeezing site was obvious in all animals of group 1-3 which was - like pain reaction - most obvious in group 1. Temporary changes in testicular consistency, as well as inflammation signs were observed in testes, epididymides and spermatic cords. During the course of the study, testes size increased (p<0.0001) independently of the group. Testosterone was within the physiological range in group 1-3 and differed significantly from group 4 (p=0.0002). Histology revealed normal spermatogenesis and fully elongated sperm in testes and epididymides. CONCLUSION: None of the three bloodless methods used led to testicular shrinking, basal testosterone concentration and disturbed spermatogenesis which would be a suitable marker for testicular atrophy indicating castration. CLINICAL RELEVANCE: Although bloodless castration seems to be an interesting alternative to surgery in rabbits, none of the methods used was successful in inducing castration effects.

[Fractures and luxations in small mammals]. / Frakturen und Luxationen beim Kleinsäuger.

Most traumata in small mammals occur at home. Diagnosis and therapy can be compared with that in the dog and cat, but species-specific differences have to be considered. For fracture treatment a butterfly-cast can be sufficient for stabilization in special cases. In most cases satisfying results can be obtained with a "tie-in-fixator" treatment. Dislocations of the elbow joint are treated by reduction or stabilization through suture techniques or temporary arthrodesis.

In vivo evaluation of deer antler trabecular bone as a reconstruction material for bone defects.

Availability of graft materials to fill up osseous defects has always been a concern in orthopaedic surgeries. Deer antler material is a primary bone structure that is easy to collect and could serve as a xenograft. This study examines the behaviour of red deer antler trabecular cylinders in critical size distal femoral epiphyseal defects in 11 rabbits, and evaluates the effect of the decellularization protocols. Two preparation regimes (A and B) were used, with and without lipids and proteins. Radiographs were taken immediately after surgery and after euthanasia 12 weeks post-implantation. Histological evaluation was performed on non-decalcified 10-µm sections with a van Gieson picro-fuchsin staining protocol. A region of interest was defined for each histological section, evaluating the inflammatory reaction, the fibrosis process, and the osteogenesis. Each histological section was microradiographed to evaluate bone contact, presence of synostosis, remodelling and ossification processes. All antler cylinders were successfully implanted. Final radiographic analysis demonstrated osteointegration of most implants at various stages. Light to moderate inflammation around the grafts was noted with only one case showing full encapsulation. A variable degree of intimacy between implant and host bone was evidenced, with bone remodelling and osteogenesis of various intensity being present in all implanted sites. No differences were found between group A and B. Removal of lipids and proteins in the grafts surprisingly did not seem to matter. Decellularization and sterilization protocols may be advocated. Although it presents several limitations, this study shows some promising results regarding antler trabecular bone osteointegration.

Comparison of endoscopic endotracheal intubation and the v-gel supraglottic airway device for spontaneously ventilating New Zealand white rabbits undergoing ovariohysterectomy.

BACKGROUND: Due to the technical difficulties with endotracheal intubation of rabbits, a prospective, randomised, controlled study was performed to compare a rabbit-specific supraglottic airway device (SGAD), the v-gel, with endoscopic endotracheal intubation (EEI) in spontaneously breathing rabbits undergoing ovariohysterectomy. METHODS: Fourteen adult female New Zealand white rabbits were randomly allocated to one of two groups based on the method of airway establishment: EEI or v-gel SGAD. Anaesthesia was induced with ketamine and xylazine and maintained using isoflurane in 100 per cent oxygen. Comparisons were made between groups based on placement time of endotracheal tube/SGAD, number of attempts and adjustments, the necessity to increase isoflurane concentrations to maintain a surgical plane of anaesthesia, arterial blood gas values, gross laryngeal evaluation, and laryngotracheal histopathology. RESULTS: Both techniques resulted in elevated arterial pCO2 levels, but the v-gel was associated with more elevated pCO2 in comparison with EEI (P=0.045). Airway trauma was histologically present but clinically negligible in both groups, with no statistically significant differences observed between techniques (P>0.05). Placement time of the v-gel was significantly faster (P=0.003) and required less technical skill than EEI, but was more easily displaced when changing the animal's position (P=0.004). CONCLUSION: The v-gel is a practical alternative to EEI for securing the airway of healthy spontaneously ventilating rabbits, provided a capnograph is utilised to ensure continuous placement. Both airway techniques appear safe and effective with few complications, as long as intermittent positive pressure ventilation can be employed to correct hypercapnia.

Continuous Rate Infusion of Ketamine Hydrochloride and Dexmedetomidine for Maintenance of Anesthesia during Laryngotracheal Surgery in New Zealand White Rabbits (Oryctolagus cuniculus).

New Zealand white rabbits (Oryctolagus cuniculus) are an established in vivo model for the study of structural and functional consequences of vocal-fold vibration. Research design requires invasive laryngotracheal procedures, and the presence of laryngospasms or pain responses (or both) hinder phonation-related data collection. Published anesthesia regimens report respiratory depression and muscle tone changes and have been unsuccessful in mitigating autonomic laryngeal responses in our protocol. Infusion of ketamine hydrochloride and dexmedetomidine hydrochloride in pediatric medicine provides effective analgesia and sedation for laryngotracheal procedures including intubation and bronchoscopy; however, data evaluating the use of ketamine-dexmedetomidine infusion in rabbits are unavailable. This study reports a new infusion regimen, which was used in 58 male New Zealand white rabbits that underwent a nonsurvival laryngotracheal procedure to induce phonotraumatic vocal-fold injury. Animals were sedated by using ketamine hydrochloride (20 mg/kg IM) and dexmedetomidine (0.125 mg/kg IM). Maintenance anesthesia was provided by using continuous rate intravenous infusion of ketamine hydrochloride (343 µg/kg/min) and dexmedetomidine (1.60 µg/kg/min). A stable plane of anesthesia with no autonomic laryngeal response (laryngospasm) was achieved in 32 of the 58 rabbits (55%). Laryngospasms occurred in 25 of 58 animals (43%) and were controlled in 20 cases (80%) by providing 0.33 mL 2% topical lidocaine, incremental increase in infusion rate, or both. Continuous rate infusion of ketamine hydrochloride-dexmedetomidine with prophylactic topical lidocaine provides a predictable and adjustable surgical plane of anesthesia, with minimal confounding respiratory and autonomic laryngeal responses, during extended-duration laryngotracheal surgery in rabbits. This regimen should be considered as an alternative to injection maintenance for prolonged, invasive procedures.

Comparison of 3 intraosseous catheter sites and methods of determining placement success in cadaver rabbits.

The study goals were to determine if intraosseous (IO) catheters can be placed with greater success into the humerus, femur, or tibia of cadaver rabbits, and to evaluate the accuracy of perceived success (PS) and objective clinical success (OCS) criteria against true intramedullary catheterization confirmed by fluoroscopy. This was a prospective study utilizing 12 rabbit cadavers. Twenty-two participants attempted IO catheter placement at 3 sites. Perceived success, OCS, and fluoroscopic true success (FTS) were recorded. A Fisher's exact test was used to compare PS, OCS, and FTS, and FTS rates between sites (P < 0.05). A Wilcoxon test was used to compare speed of placement (P < 0.05). Overall, of 66 attempts, PS was reported in 86.4%, OCS was documented in 62.1%, FTS was confirmed in 43.9%. Perceived success and OCS overestimated FTS (P ≤ 0.01 and P = 0.027, respectively). Confirmation of FTS occurred in 10/22 (45.5%) humeral, 5/22 (22.7%) femoral, and 14/22 (63.6%) tibial (P = 0.03) attempts. Median time until placement for the humerus was 37.5 seconds (range: 15 to 125 seconds); the femur 135 seconds (range: 91 to 148 seconds); the tibia 49 seconds (range: 19 to 150 seconds). The humerus and tibia were faster to catheterize than the femur (P = 0.01 and 0.03, respectively). Participant PS and OCS criteria overestimated FTS. The humerus or tibia may be more successful and are faster to catheterize.

Les objectifs de la présente étude étaient de déterminer si des cathéters intra-osseux (IO) peuvent être placés avec plus de succès dans l'humérus, le fémur ou le tibia de cadavres de lapins, et d'évaluer la précision des critères du succès perçu (PS) et du succès clinique objectif (OCS) versus le cathétérisme intramédullaire réel confirmé par fluoroscopie. Il s'agissait d'une étude prospective utilisant 12 cadavres de lapin. Vingt-deux participants ont tenté le placement des cathéters IO aux trois sites. Le PS, l'OCS et le succès réel par fluoroscopie (FTS) furent notés. Un test exact de Fisher fut utilisé pour comparer PS, OCS, et FTS, et les taux de FTS entre les sites (P < 0,05). Un test de Wilcoxon a été utilisé pour comparer la vitesse de placement (P < 0,05). Globalement, des 66 essais, PS a été rapporté dans 86,4 % des cas, OCS a été documenté dans 62,1 % des cas, et FTS a été confirmé dans 43,9 % des cas. Le PS et l'OCS surestimaient le FTS (P ≤ 0,01 et P = 0,027, respectivement). La confirmation de FTS s'est produite dans 10/22 (45,5 %) des essais sur l'humérus, 5/22 (22,7 %) des essais sur le fémur, et 14/22 (63,6 %) des essais sur le tibia (P = 0,03).Le temps médian du placement pour l'humérus était de 37,5 secondes (écart : 15 à 125 secondes); pour le fémur de 135 secondes (écart : 91 à 148 secondes); et pour le tibia de 49 secondes (écart : 19 à 150 secondes). Le cathétérisme de l'humérus et du tibia étaient plus rapides que celui du fémur (P = 0,01 et 0,03, respectivement). Les critères pour le PS et l'OCS des participants surestimaient le FTS. L'humérus et le tibia sont plus rapides à cathétériser et le taux de succès est meilleur.(Traduit par Docteur Serge Messier).

Experimental middle ear surgery in rabbits: a new approach for reconstructing the ossicular chain.

This experimental animal study aimed at evaluating a new prosthesis to replace the ossicular chain; we developed a new technique for surgical implantation into the middle ear of rabbits. The rabbit middle ear is, owing to the relative anatomical dimensions involved, an ideal environment for implantation procedures involving the ossicles, as the surgical conditions are similar to those of the human middle ear. This study included a total of 34 approximately six-month-old female white rabbits (New Zealand) weighing between 3.2 and 4.4 kg. The implants used were constructed of ceramic materials (titania, TiO(2)) of various pore sizes. Directly prior to implanting the total ossicular reconstruction prostheses (TORPs), as well as at 28, 84 and 300 days after implantation, electric response audiometry was used to determine the hearing thresholds of the animals (bone conduction; click stimulus nHL). An erbium:YAG laser was used to excise the original ossicular chain. Following implantation, we were unable to detect any stenosis of the outer ear canal or perforation of the tympanic membrane. The conductive hearing threshold was in the range of 4.21 +/- 6.68 dB nHL (n = 131). The hearing level showed no significant difference before and after surgery (P < 0.05).

Induction of anaesthesia with either midazolam or propofol in rabbits premedicated with fentanyl/fluanisone.

Fifty-four rabbits that were to be neutered were premedicated with 0.1 ml/kg fentanyl/fluanisone and then randomly allocated to be anaesthetised with either midazolam or propofol. Anaesthesia was then maintained with isoflurane. The ease of orotracheal intubation, the rabbits' cardiorespiratory variables, and the speed and quality of recovery from anaesthesia were assessed by the same anaesthetist who was unaware of the induction agent used. Hypotension was common in both groups. The mean (sd) respiratory rates were 30 (12) breaths per minute in the midazolam group and 43 (15) breaths per minute in the propofol group. The mean (sd) time to first head lift was 36 (21) minutes in the midazolam group and 14 (11) minutes in the propofol group, and the mean (sd) times to the return of the righting reflex were 35 (19) minutes and 15 (eight) minutes, respectively. The quality of recovery was better in the propofol group than in the midazolam group.