Efficacy of Postoperative Antimicrobial Use for Clean Orthopedic Implant Surgery in Dogs: A Prospective Randomized Study in 100 Consecutive Cases

Effects of storage up to 1 year on the in vitro antimicrobial activity of preformulated antibiotic-impregnated calcium sulfate beads

OBJECTIVE

To compare antimicrobial activity as demonstrated by the zone of inhibition (ZOI) produced by antibiotic-impregnated calcium sulfate (CaSO4) beads after storage for 0, 3, 6, 9, and 12 months.

STUDY DESIGN

Controlled laboratory study.

SAMPLE POPULATION

Three-millimeter diameter CaSO4 beads impregnated with vancomycin (125 mg/mL), or amikacin (250 mg/mL), or without antibiotic (control).

METHODS

Calcium sulfate beads were created at the onset of the study. Individual beads were separated in sterile containers and stored in a closed cabinet at room temperature and humidity for 0, 3, 6, 9, or 12 months until testing. The ZOI against methicillin-resistant Staphylococcus pseudintermedius, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa was recorded with serial replating on a fresh lawn of bacteria every 24 h until beads failed to produce a ZOI. The ZOIs and their changes were compared with mixed-effects linear models. Eluted concentrations of vancomycin measured with high-performance liquid chromatography were reported.

RESULTS

At 24 h, ZOIs were comparable regardless of time since formulation, except vancomycin against P. aeruginosa, which failed to generate a ZOI. The daily changes of ZOI and duration of activity of antibiotics did not vary between storage length (p > .05). There was no consistent change in eluted drug concentration between storage length of beads.

CONCLUSION

Light protected storage at room temperature for up to 12 months did not impair the in vitro activity of antibiotic-impregnated CaSO4 beads, as demonstrated through ZOIs.

CLINICAL SIGNIFICANCE

When stored correctly, antibiotic-impregnated CaSO4 beads can be used at least up to 12 months after formulation.

Population pharmacokinetic meta-analysis of five beta-lactams antibiotics to support dosing regimens in dogs for surgical antimicrobial prophylaxis

The Pharmacokinetic/Pharmacodynamic (PK/PD) relationship of antimicrobial drugs (AMD) for surgical prophylaxis has been poorly studied, hampering evidence-based decision making around AMD dosing and timing. Our objective is to use PK/PD principles to inform (1) the timing of administration and (2) the interval for re-administration of AMD used peri-operatively in dogs. Raw plasma concentrations of cefazolin, cefuroxime, cefalexin, amoxicillin and ampicillin were retrieved from original intravenous studies performed in dogs. E. coli and methicillin-susceptible staphylococci were identified as possible intraoperative contaminants and their epidemiological cut-offs (ECOFF) were retrieved from the EUCAST database. Individual PK data were refitted with non-linear mixed effect models (Phoenix®). We performed Monte Carlo simulation to compute i) the 95th percentile of time of peak concentration in the peripheral compartment (informing timing between administration and first incision) and ii) the duration for which at least 90% of dogs maintain a free plasma concentration above ECOFF (informing timing of re-administration: 1.5-4 h). Cefazolin (22-25 mg/kg), cefuroxime (20 mg/kg), cefalexin (15 mg/kg) and amoxicillin (16.7 mg/kg) reached peak peripheral concentrations within 30 min, but ampicillin (20 mg/kg) required 82 min, respectively. For methicillin-susceptible staphylococci, cefazolin and cefuroxime require re-administration every 2 h, whereas cefalexin and both amoxicillin and ampicillin can be readministered every 3 and 4 h, respectively. For E. coli, only cefazolin provided adequate perioperative coverage with 2-hourly administration, where cefuroxime and cefalexin failed uniformly. Alternatively, ampicillin and amoxicillin (critically ill dogs) may cover E. coli contaminations, but only if readministered every 1.5 h. These PK-derived conclusions provide a rationale for perioperative AMD administration timing.

Clinical relevance of positive intraoperative bacterial culture in tibial plateau leveling osteotomy in dogs: a retrospective study

BACKGROUND

Tibial plateau leveling osteotomy (TPLO) belongs to the most frequently used surgical method for the treatment of cranial cruciate ligament rupture in dogs. Surgical site infection (SSI) is one of the possible postoperative complications. The aim of this study was to evaluate the diagnostic value of intraoperative bacterial culture as a tool for the detection of intraoperative bacterial contamination progressing to infection development in canine TPLO. Electronic patient records from dogs who underwent TPLO between January 2018 to December 2020 were retrospectively reviewed. Intraoperative bacterial culture results, used antimicrobial drugs and presence of SSI were recorded.

RESULTS

Ninety-eight dogs were included in the study. SSI rate was 10.2%. All dogs who developed SSI (n = 10) had negative intraoperative bacterial cultures. None of the dogs with positive intraoperative bacterial culture (n = 6) developed SSI. The most cultured bacteria causing SSI was Staphylococcus pseudintermedius (n = 4).

CONCLUSIONS

Intraoperative bacterial culture in dogs undergoing TPLO is not suitable as a predictor of surgical site infection.

Antimicrobial prophylaxis in companion animal surgery: A scoping review for European Network for Optimization of Antimicrobial Therapy (ENOVAT) guidelines

Surgical antimicrobial prophylaxis (SAP) is widely used to reduce the risk of surgical site infections (SSI), but there is uncertainty as to what the proportion of SSI reduction is. Therefore, it is difficult for surgeons to properly weigh the costs, risks and benefits for individual patients when deciding on the use of SAP, making it challenging to promote antimicrobial stewardship in primary practice settings. The objective of this study was to map the veterinary evidence focused on assessing the effect of SAP on SSI development and in order to identify surgical procedures with some research evidence and possible knowledge gaps. In October 2021 and December 2022, Scopus, CAB Abstracts, Web of Science Core Collection, Embase and MEDLINE were systematically searched. Double blinded screening of records was performed to identify studies in companion animals that reported on the use of SAP and SSI rates. Comparative data were available from 34 out of 39123 records screened including: eight randomised controlled trials (RCT), 23 cohort studies (seven prospective and 16 retrospective) and three retrospective case series representing 12476 dogs and cats in total. Extracted data described peri- or post-operative SAP in nine, and 25 studies, respectively. In the eight RCTs evaluating SAP in companion animals, surgical procedure coverage was skewed towards orthopaedic stifle surgeries in referral settings and there was large variation in SAP protocols, SSI definitions and follow-up periods. More standardized data collection and agreement of SSI definitions is needed to build stronger evidence for optimized patient care.

Evaluation of a client questionnaire at diagnosing surgical site infections in an active surveillance system

OBJECTIVE

To report sensitivity, specificity, predictive values and accuracy of a client questionnaire at diagnosing surgical site infections (SSIs) and describe the impact of active surveillance on SSI detection.

STUDY DESIGN

Prospective, cohort study.

ANIMALS

Dogs and cats undergoing soft tissue or orthopedic surgery over a 12-month period at a referral hospital.

METHODS

Clients were emailed a questionnaire 30 days postoperatively, or 90 days where an implant was used. Three algorithms were developed to diagnose SSIs using one or both of two criteria: (1) presence of any wound healing problems; (2) wound dehiscence or antibiotic prescription, and either purulent discharge or two or more clinical signs (redness, pain, heat, swelling, discharge). Algorithmic diagnoses were compared to gold standard diagnoses made by veterinarians.

RESULTS

Of 754 surgical procedures, 309 responses were completed with 173 corresponding gold standard diagnoses. The most accurate algorithm determined "SSI" or "No SSI" from 90.2% of responses with 95.5% (92.4-98.6) accuracy, 82.6% (77-88.3) sensitivity, 97.7% (95.5-100) specificity, 86.4% (81.2-91.5) positive predictive value, and 97% (94.5-99.6) negative predictive value. "No SSI" was diagnosed in responses not meeting criterion 1, and "SSI" in responses meeting criteria 1 and 2. "Inconclusive" responses, comprising 9.8% of responses, met criterion 1 but not 2. Overall SSI rate was 62/754 (8.2%) and 12/62 (19.4%) SSIs were detected by active surveillance only.

CONCLUSION

Use of this client questionnaire accurately diagnosed SSIs; active surveillance increased SSI detection.

CLINICAL SIGNIFICANCE

Surveillance of SSIs should be active and can be simplified by using a client questionnaire and algorithmic diagnoses, allowing automated distribution, data collection and analysis.

Influence of antiseptic lavage during tibial plateau leveling osteotomies on surgical site infection in 1422 dogs

OBJECTIVE

To determine the influence of preclosure antiseptic versus saline lavage on surgical site infections (SSI) in dogs following tibial plateau leveling osteotomy (TPLO).

STUDY DESIGN

A multicenter retrospective study.

SAMPLE POPULATION

Dogs treated with TPLO (n = 1422) between December 2019 and October 2021.

METHODS

The medical records of dogs treated with TPLO were reviewed for preclosure antiseptic lavage or saline irrigation. Additional collected data included signalment, unilateral or bilateral TPLO, postoperative administration of antimicrobial medications, antibiotic agent, surgeon, and development of SSI within 90 postoperative days. Eleven factors were analyzed for association with SSI using univariate and multivariate analysis.

RESULTS

Data were collected from the records of 519 dogs treated with antiseptic lavage and 903 dogs treated with saline lavage during TPLO. Surgical site infections were diagnosed more frequently in dogs that received preclosure antiseptic lavage (77/519, 14.84%) than those with saline irrigation (80/903, 8.86%) (p = .001). Single session bilateral TPLO increased the odds of SSI by 2.5x (p = .004). The odds of SSI increased by 11% (p = .001) for every 5 kg increase in bodyweight. Postoperative administration of antimicrobials decreased the risk of SSI (p = .008).

CONCLUSION

The preclosure antiseptic lavage tested here did not decrease the incidence of SSI after TPLO.

CLINICAL SIGNIFICANCE

The results of this study do not provide evidence to support preclosure antiseptic lavage during TPLOs.

Prospective measurement of outcomes and complications of tibial tuberosity advancement using novel mini plates in small breed dogs

Cranial cruciate ligament (CrCL) disease is a common orthopedic disease in canine patients. Tibial osteotomy procedures for the treatment of cranial cruciate ligament disease in small breed dogs (<15 kg) have previously been limited. A total of 22 client-owned dogs, 26 stifles, with cranial cruciate ligament disease were treated with novel mini-tibial tuberosity advancement plates. The most common intraoperative complications included the need for plate-cage overlap in 7 stifles (26.92%) and screw head fracture in 1 (3.85%). Post-operative complications included tibial tuberosity fracture (3.85%), post-operative medial patella luxation (7.69%), and persistent lameness (7.69%). Of the 26 stifles evaluated in the medium term (>6-12 months) post-operatively, 92.3% had no lameness, with the remaining 7.7% having Grade 1 lameness. A good to excellent clinical outcome was noted in all 26 stifles that underwent TTA with novel mini plates.

In Vitro and In Vivo Studies of Antibacterial Coatings on Titanium Alloy Implants for Veterinary Application

The aim of this work was the evaluation of biological properties of hybrid coatings modified with Ag, Cu, and Zn nanoparticles (NPs) applied on TPLO medical implants by the sol-gel process. The implant coatings enriched with various concentrations of metallic NPs were investigated in the in vitro bactericidal efficacy tests against Gram+ and Gram- bacteria and pathogenic yeast. Next, the designed materials were tested on human osteosarcoma cell lines. The cells adhesion, proliferation, viability, and differentiation were investigated. The cell growth wasevaluated using SEM, and the metallic ion release was measured. The results revealed that the NPs concentration in the hybrid layers decreased with the incubation time. In the last stage, the implants were tested in vivo on six canine patients. Three months after the operation, the radiological evaluation of the performed anastomosis was carried out as well as the histopathological evaluation of tissue regeneration. The strongest bactericidal efficacy was observed for the layers containing AgNPs. Along with an increased concentration of metallic additives, a growing toxic effect was clearly observed. The most pronounced toxic effect was especially evident with the AgNPs concentration exceeding 1 mol %. In all the operated patients, no deviations were found during the follow-up examinations in the postoperative period. The low dose of AgNPs in the hybrid layer facilitated the tissue healing process. It was proven that silver nanoparticles may accelerate the bone healing process. The correct tissue reparation was observed.

Rate of surgical site and urinary tract infections in dogs after cessation of antibiotics following spinal surgery

BACKGROUND

Excessive use of antimicrobials and the increasing occurrence of antimicrobial resistance are major challenges in both human and veterinary medicine. The role of prophylactic antimicrobial therapy in orthopaedic and neurosurgeries in dogs can be questioned. The aim of this study was to evaluate the rate of surgical site infections (SSI) and urinary tract infections (UTI) in dogs after cessation of antibiotics following spinal surgery.

METHODS

Electronic patient records from January 2018 to December 2019 were retrospectively reviewed to identify dogs that underwent spinal surgery (n = 158). Antimicrobial drug use and the presence of SSI and UTI were recorded.

RESULTS

Overall, SSI developed in 1.3% of dogs that underwent spinal surgery, while UTI developed in 8.2%. Multidrug-resistant (MDR) bacteria were detected in 5.1% of dogs. The rates of SSI, UTI and MDR did not differ significantly between dogs that received postoperative antimicrobial therapy and those that did not.

LIMITATIONS

The main limitation of this study was its retrospective design.

CONCLUSION

Overall, the SSI rate in this study was low. Cessation of postoperative antimicrobial use in dogs following spinal surgery did not have a negative effect on either SSI development or the occurrence of UTI.

Biomechanical Comparison of Tibial Plateau Leveling Osteotomy Performed With a Novel Titanium Alloy Locking Plate Construct vs. an Established Stainless-Steel Locking Plate Construct

A novel canine tibial plateau leveling osteotomy (TPLO) fixation device was recently developed with design features such as titanium alloy (TA) material, distal monocortical screw fixation, and a point contact undersurface specifically targeted to reduce surgical site infection rates by ensuring tissue perfusion under the plate. The strength of the novel TPLO construct was compared with that of a predicate stainless steel (SS) locking plate construct with bicortical screws in 16 paired cadaveric canine limbs. The mean loads to failure were 716.71 ± 109.50 N (range 455.69–839.69 N) and 629.50 ± 176.83 N (range 272.58–856.18 N) in the TA and SS groups, respectively. The average ratio of the loads to failure of the paired specimens was 1.18 (p = 0.031). No failure of the TA constructs involved the distal fixation with monocortical screws. Substantial mechanical equivalence of this novel TA monocortical/bicortical fixation construct to an established SS bicortical screw fixation construct is demonstrated. Clinical investigation of potential merits of this novel TA, monocortical/bicortical locking screw/plate system is now warranted.

Evaluation of post-operative complications, outcome, and long-term owner satisfaction of elbow arthrodesis (EA) in 22 dogs

The objective of this study was to report post-operative complications and outcomes in canines undergoing elbow arthrodesis (EA) with fixation techniques including bone plate fixation with a non-locking dynamic compression plate (DCP), bone plate fixation with a locking plate (LCP), and external skeletal fixator (ESF). Medical records of twenty-two cases that underwent EA between January 2009-December 2019 from 8 referral hospitals including both private practice and academic institutions were reviewed. Post-operative complications were classified as either minor or major, surgical evaluations were performed 8 weeks post operatively, and a follow-up questionnaire was sent to owners. Of the total 22 cases that met inclusion criteria, a total of 19/22 cases had complications, 12 major and 7 minor. Complications reported in 8/9, 7/9, and 4/4, for the DCP, LCP, and ESF fixation groups, respectively. Mild to moderate mechanical lameness was identified at surgical evaluation in 16/22 cases. Complete radiographic bone healing was achieved after 9 weeks in 19/22 cases. Long term owner follow up was available in 14/22 cases. Owners reported a good to normal quality of life in 13/14 cases and poor in one case. The majority of owners (11/14) reported good to excellent satisfaction with the outcome irrespective of persistent lameness. This study demonstrates that successful EA can be achieved using a variety of fixation methods, but persistent lameness is expected and complication rate is high.

Effect of three different needle holders on gastrointestinal anastomosis construction time and bursting pressure in equine jejunal segments

Background

Equine small intestinal resection and anastomosis is a procedure where optimizing speed, without compromising integrity, is advantageous. There are a range of different needle holders available, but little is published on the impact surgical instrumentation has on surgical technique in veterinary medicine.

The objectives of this study were to investigate if the needle holder type influences the anastomosis construction time, the anastomosis bursting pressure and whether the bursting pressure is influenced by the anastomosis construction time.

Single layer end-to-end jejunojejunal anastomoses were performed on jejunal segments harvested from equine cadavers. These segments were randomly allocated to four groups. Three groups based on the needle holder type that was used: 16.5 cm Frimand (Group 1), 16 cm Mayo-Hegar (Group 2) or 20.5 cm Mayo-Hegar (Group 3) needle holders. One (Group 4) as control without anastomoses. Anastomosis construction time was recorded. Bursting pressure was determined by pumping green coloured fluid progressively into the lumen whilst recording intraluminal pressures. Maximum pressure reached prior to failure was recorded as bursting pressure. Construction times and bursting pressures were compared between needle holder, and the correlation between bursting pressure and construction time was estimated.

Results

Construction times were not statistically different between groups (P = 0.784). Segments from Group 2 and Group 3 burst at a statistically significantly lower pressure than those from Group 4; P = 0.031 and P = 0.001 respectively. Group 4 and Group 1 were not different (P = 0.125). The mean bursting pressure was highest in Group 4 (189 ± 61.9 mmHg), followed by Group 1 (166 ± 31 mmHg) and Group 2 (156 ± 42 mmHg), with Group 3 (139 ± 34 mmHg) having the lowest mean bursting pressure. Anastomosis construction time and bursting pressure were not correlated (P = 0.792).

Conclusions

The tested needle holders had a significant effect on bursting pressure, but not on anastomosis construction time. In an experimental setting, the Frimand needle holder produced anastomoses with higher bursting pressures. Further studies are required to determine clinical implications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02871-4.

Risk factors for surgical site infection associated with clean surgical procedures in dogs

Surgical site infection (SSI) is associated with increased morbidity, cost and mortality in human medicine and with increased morbidity and cost in veterinary medicine. The aim of this study was to evaluate risk factors for SSI development after clean surgical procedures in dogs, treated at both first opinion clinics as well as referral hospitals. 1550 dogs scored 1 or 2 according to the American Society of Anesthesiologists (ASA), that underwent clean surgical procedures at 103 clinics located in Northern and Central Europe were included in the study. Data regarding the surgical procedure, surgery time use of perioperative antimicrobial prophylaxis (AMP), surgery type, intraoperative hypothermia, and the use of surgical implants were recorded according to predefined protocols. Active 30-day SSI surveillance was performed. A random effects logistic regression model was used to evaluate the association between the perioperative variables and SSI development. SSI was detected in 85/1550 dogs (5.5%); 25 occurred in the 500 orthopedic/neurosurgery procedures (5.0%), and 60 in the 1050 soft tissue procedures (5.7%). A total of 1524 dogs were included in the final multivariable model. Increased surgery time was the only variable associated with an increased risk of SSI. No association between the other risk factors evaluated in the study and SSI occurrence was detected. Efforts must therefore be made to keep the surgery time as short as possible. Orthopedic and neurosurgical procedures including those where an implant is placed should not automatically be regarded as high-risk procedures benefiting from perioperative AMP.

Efficacy of postoperative antibiotic use after tibial plateau leveling osteotomy in dogs: A systematic review

OBJECTIVE

A systematic review of published data to determine whether postoperative antibiotic use after tibial plateau leveling osteotomy (TPLO) decreases infection rates.

STUDY DESIGN

Systematic review.

METHODS

A broad bibliographic search was performed in three online databases through March 2020 for publications on postoperative antibiotic use after TPLO in dogs. Search terms included dog, canine, TPLO, tibial plateau leveling osteotomy, infection, antibiotic, and antimicrobial. Articles that met inclusion criteria were evaluated for level of evidence (LoE) by a modified Oxford Level of Evidence (mOLE) and GRADE (Grading of Recommendations, Assessment, Development and Evaluation) classification and evaluation.

RESULTS

Thirteen studies met the inclusion criteria. Effect of antibiotic use was the primary question in four studies. Among those, 50% (2/4) were assigned a mOLE of 1b and a GRADE of moderate, while the other 50% (2/4) were assigned a mOLE of 4b or 4c with a GRADE of low. The two studies with the highest LoE did not provide evidence of the benefit of antibiotic usage. Results of only one study provided evidence to support the use of postoperative antibiotics. The remaining nine studies provided evaluation of antibiotic use secondarily and were all assigned a low LoE. Among these, 78% (7/9) provided evidence to support the use of postoperative antibiotics.

CONCLUSION

We found little evidence to support the use of postoperative antibiotics to reduce the risk of surgical site infections in dogs after TPLO. The answer to this clinical question is complicated by the lack of prospective studies and inconsistent treatment protocols in the evaluated studies.

CLINICAL SIGNIFICANCE

The clinical impact of postoperative antibiotic administration on infection rates after TPLO is uncertain.

Calcium sulfate antibiotic-impregnated bead implantation for deep surgical site infection associated with orthopedic surgery in small animals

OBJECTIVE

To report the outcomes and complications associated with antibiotic-impregnated calcium sulfate beads for prevention and treatment of orthopedic-related surgical site infection (SSI) in companion animals.

STUDY DESIGN

Retrospective case series.

ANIMALS

Client-owned cats (n = 2) and dogs (n = 14).

METHODS

Medical records of 16 cases in which implantation of antibiotic-impregnated calcium sulfate beads was performed for the prevention or treatment of SSI were reviewed. Information collected included signalment, prior surgery, reason for bead placement, antibiotics used, bacterial culture results, and clinical outcomes.

RESULTS

Surgical site infection resolved in six of 10 animals treated therapeutically and did not occur in six of six animals treated prophylactically. Susceptibility of the causative bacteria to the antibiotic implanted was confirmed in five of six cases with resolved SSI treated therapeutically but in only one of four cases with unresolved SSI treated therapeutically. Complications directly related to bead placement were evident in only one case in which beads extruded from external skeletal fixator pin tracts 7 days after implantation. At final follow-up, 11 of 12 animals without SSI had satisfactory limb use and no clinical, cytologic, or radiographic evidence of infection.

CONCLUSION

Implantation was well tolerated. Resolution of SSI was inconsistent; however, when bacteria were susceptible to the antibiotic implanted, SSI resolved in all but one case.

CLINICAL SIGNIFICANCE

Antibiotic-impregnated calcium sulfate beads could be considered for prevention or treatment of orthopedic SSI in small animals. A prospective clinical study is required to obtain additional information, including the value of preoperative bacterial culture.

A retrospective evaluation of complications associated with forkless tibial tuberosity advancement performed in primary care practice

OBJECTIVE

To report postoperative complications associated with forkless tibial tuberosity advancement (TTA) performed in primary care veterinary practice and to compare results with previous publications.

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Three hundred seventy-four forkless TTAs in 329 dogs performed by six nonspecialist veterinarians.

METHODS

Medical records of dogs treated with a standard forkless TTA (2013-2016) and with at least 12 months of postoperative follow-up were reviewed. Complications recorded by the referring practice or the operating veterinarian were classified as minor (medically treated) or major (surgically treated).

RESULTS

Complications occurred in 57 of 374 (15.2%) TTAs; 28 (7.5%) complications were major, and 29 (7.7%) complications were minor. Postliminary meniscal injuries were documented in 12 of 374 (3.2%) TTAs (12/57 major complications) and were more common when the ratio of cage size to bodyweight was ≤0.25 (P = .019). Mean TTA (cage size) was greater in this population than what has been previously reported for a lower median bodyweight.

CONCLUSION

The incidence of major complications was low and within the range previously reported for TTA in referral practice after adjusting for study design. The magnitude of advancement was greater, and the incidence of postliminary meniscal injury was lower than what has been previously reported, after accounting for dogs that had a preliminary meniscal injury or medial meniscal release.

CLINICAL SIGNIFICANCE

Forkless TTA may be successfully performed by experienced veterinarians in primary care practice with a low rate of complications. The incidence of postliminary meniscal injury may be reduced by a greater degree of advancement of the tibial tuberosity.

Investigation of Variables Associated with Surgical Site Infection following the Management of Canine Cranial Cruciate Ligament Rupture with a Lateral Fabellotibial Suture

OBJECTIVE

 This study investigated variables associated with surgical site infection (SSI) in dogs with cranial cruciate ligament rupture managed with stifle joint examination and lateral fabellotibial suture stabilization.

STUDY DESIGN

 A retrospective study of dogs that had stifle arthroscopy, stifle arthrotomy, or a combination of both, followed by lateral fabellotibial suture stabilization for cranial cruciate ligament rupture. All cases had a minimum follow-up of 90 days. Lameness grades were recorded preoperatively, and at 6-week and final follow-up.

RESULTS

 One hundred fifty procedures in 130 dogs met the inclusion criteria. Overall, SSI rate was 17.3% and removal of the lateral fabellotibial suture was performed in 53% of SSI. Multivariable analysis showed significant association between SSI and bodyweight (p = 0.013), and induction using propofol (p = 0.029). Multilevel ordinal logistic regression analysis showed a greater proportion of dogs had a higher lameness grade at 6-week (p = 0.021) and final follow-up (p = 0.002) assessments in the infected compared with non-infected dogs.

CONCLUSION

 Our study demonstrated a higher SSI incidence than previously reported in dogs undergoing a lateral fabellotibial suture for cranial cruciate ligament rupture. Bodyweight and induction with propofol were identified as significant risk factors for postoperative SSI. Owners could be advised of an increased SSI risk in larger dogs and consideration should be given to selection of induction agent. Dogs that develop an SSI have a worse lameness grade at 6-week and final follow-up.

Antimicrobial prophylaxis is considered sufficient to preserve an acceptable surgical site infection rate in clean orthopaedic and neurosurgeries in dogs

Background

Surgical site infections (SSI) are associated with increased morbidity and mortality. To lower the incidence of SSI, antimicrobial prophylaxis is given 30–60 min before certain types of surgeries in both human and veterinary patients. However, due to the increasing concern of antimicrobial resistance, the benefit of antimicrobial prophylaxis in clean orthopaedic and neurosurgeries warrants investigation. The aims of this retrospective cross-sectional study were to review the rate of SSI and evaluate the compliance with antimicrobial guidelines in dogs at a veterinary teaching hospital in 2012–2016. In addition, possible risk factors for SSI were assessed.

Results

Nearly all dogs (377/406; 92.9%) received antimicrobial prophylaxis. Twenty-nine dogs (7.1%) did not receive any antimicrobials and only four (1.1%) received postoperative antimicrobials. The compliance with in-house and national protocols was excellent regarding the choice of prophylactic antimicrobial (cefazolin), but there was room for improvement in the timing of prophylaxis administration. Follow-up data was available for 89.4% (363/406) of the dogs. Mean follow-up time was 464 days (range: 3–2600 days). The overall SSI rate was 6.3%: in orthopaedic surgeries it was 6.7%, and in neurosurgeries it was 4.2%. The lowest SSI rates (0%) were seen in extracapsular repair of cranial cruciate ligament rupture, ulnar ostectomy, femoral head and neck excision, arthrotomy and coxofemoral luxation repair. The highest SSI rate (25.0%) was seen in arthrodesis. Omission of antimicrobials did not increase the risk for SSI (P = 0.56; OR 1.7; CI_95% 0.4–5.0). Several risk factors for SSI were identified, including methicillin-resistant Staphylococcus pseudintermedius carriage (P = 0.02; OR 9.0; CI_95% 1.4–57.9) and higher body temperature (P = 0.03; OR 1.69; CI_95% 1.0–2.7; mean difference + 0.4 °C compared to dogs without SSI).

Conclusions

Antimicrobial prophylaxis without postoperative antimicrobials is sufficient to maintain the overall rate of SSI at a level similar to published data in canine clean orthopedic and neurosurgeries.

Contributing factors to surgical site infection after tibial plateau leveling osteotomy: A follow-up retrospective study

OBJECTIVE

To identify factors associated with surgical site infection (SSI) after tibial plateau leveling osteotomy (TPLO).

STUDY DESIGN

Retrospective case series.

ANIMALS

Dogs (n = 541) that underwent TPLO (n = 659).

METHODS

Medical records of dogs that underwent TPLO from 2011-2018 were reviewed. Data collected included perioperative and postoperative antimicrobial administration, stifle inspection, duration of surgery and anesthesia, comorbidities, and development of SSI including timing, microbiological investigation, and implant removal. Referring veterinarians were contacted for all dogs without a recorded return visit. Risk factors for SSI were assessed by using a multivariable logistic regression model built by using a stepwise approach.

RESULTS

Surgical site infection was documented in 71 of 659 (11%) TPLO, with methicillin-resistant Staphylococcus pseudintermedius accounting for 20 of 71 (28%) infections. Protective factors against SSI included administration of postoperative antimicrobials (odds ratio [OR] 0.263; 95% CI = 0.157, 0.442) and timing of preoperative antimicrobial administration. Preoperative antimicrobial timing was protective against SSI when it was administered more than 60 minutes before the first incision compared with administration within 30 minutes (OR 0.275; 95% CI = 0.112, 0.676) or within 60 minutes (OR 0.419; 95% CI = 0.189, 0.929) of the first incision.

CONCLUSION

Early administration of perioperative antimicrobials and postoperative antimicrobial administration were protective against SSI after TPLO.

CLINICAL SIGNIFICANCE

Antimicrobials can influence the risk of SSI after TPLO. Perioperative and postoperative antimicrobial administration timing should be considered to reduce SSI.

Three-Dimensional-Printed Patient-Specific Osteotomy Guides, Repositioning Guides and Titanium Plates for Acute Correction of Antebrachial Limb Deformities in Dogs

OBJECTIVE

 The aim of this study was to describe the use of patient-specific three-dimensional (3D)-printed osteotomy guides, repositioning guides and custom-printed titanium plates for acute correction of antebrachial limb deformities in four dogs.

METHODS

 Retrospective review of antebrachial limb deformities in small breed chondrodystrophic dogs that were surgically corrected using a closing wedge ostectomy of the radius at a predetermined site using patient-specific osteotomy guides. Reduction was achieved without the need for intraoperative measurements using patient-specific 3D-printed repositioning guides secured and manipulated using temporary Kirschner wire fixation. The ostectomy of the radius was stabilized with a patient-specific 3D-printed titanium plate.

RESULTS

 All limbs were corrected to within 3.5 degrees (standard deviation [SD]: 1 degree) and 7.5 degrees (SD: 3 degrees) of the pre-planned deformity correction in the frontal and sagittal planes, respectively. No complications were encountered. Owners completed a canine orthopaedic index survey at a median postoperative follow-up time of 19 months. Surgery eliminated the main presenting complaint of buckling over of the manus in all cases.

CLINICAL SIGNIFICANCE

 The 3D-printed osteotomy repositioning guides and titanium plates facilitated accurate acute correction of antebrachial deformities in this case series. The methodology described simplifies intraoperative surgical decision-making on limb position with good clinical outcomes seen in a small number of clinical cases.

Influence of administration of antimicrobial medications after tibial plateau leveling osteotomy on surgical site infections: A retrospective study of 308 dogs

OBJECTIVE

To determine the influence of prophylactic administration of oral antimicrobial medications after tibial plateau leveling osteotomy (TPLO) on surgical site infections (SSI) and antimicrobial-resistant infections.

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Dogs treated with unilateral TPLO (n = 308) between January 2013 and December 2015.

METHODS

Medical records were reviewed for signalment, surgically treated limb, duration of surgery and anesthesia, postoperative administration of antimicrobial medications, antibiotic agent, surgeon, and development of SSI. Statistical analyses included descriptive statistics, simple linear regression, analysis of variance, Fisher's protected least significant difference, and χ² testing.

RESULTS

Data were collected from records of 31 dogs that did not receive antimicrobial medications and 277 dogs that did receive oral antimicrobial medications for 14 days after TPLO. Superficial incisional SSI was detected in two of 31 dogs that did not receive antimicrobial medications and in 48 of 277 dogs that did receive antimicrobial medications (P = .1194). Deep incisional SSI occurred in two of 31 dogs that did not receive antimicrobial medications and in 27 of 277 dogs that did receive antimicrobial medications (P = .5513). Antibiotic-resistant deep incisional SSI occurred in two of 31 dogs that did not receive antimicrobial medications and in 18 of 277 dogs that did receive antimicrobial medications (P = .9920). Body weight correlated with deep incisional SSI and resistant infections. Prolonged duration of surgery and anesthesia were associated with superficial incisional SSI, deep incisional SSI, and antibiotic resistance. Surgeons influenced deep incisional SSI.

CONCLUSION

Previously reported predisposing factors for infection were confirmed, but postoperative administration of antimicrobial medications was not protective against SSI nor did it predispose to antibiotic resistance in our clinical setting.

CLINICAL SIGNIFICANCE

This study does not provide evidence to support administration of prophylactic oral antimicrobial medications after unilateral TPLO.

Risk of infection after double locking plate and screw fixation of tibial plateau leveling osteotomies in dogs weighing greater than 50 kilograms

OBJECTIVE

To compare surgical site infection (SSI) rates after double locking plate and screw fixation (DLP), standard locking plate and screw fixation (LP), and conventional nonlocking plate and screw fixation (NLP) in dogs weighing >50 kg undergoing tibial plateau leveling osteotomy (TPLO).

STUDY DESIGN

Retrospective study (January 2003-October 2017).

ANIMALS

Two hundred seventy-five dogs weighing >50 kg with cranial cruciate ligament disease treated with TPLO.

METHODS

Medical records of dogs weighing >50 kg that underwent TPLO by DLP, LP, and NLP with a minimum follow-up period of 12 months were included. Data collected included signalment, details of any concurrent surgical procedure, type of implant used, use of postoperative antibiotic therapy, occurrence of perioperative complications, and presence of postoperative infection. The probability, risk difference, and relative risk of SSI were estimated for each fixation with a marginal model.

RESULTS

Nonlocking plate and screw fixation was used in 114 (41.5%) dogs, LP was used in 128 (46.5%) dogs, and DLP was used in 33 (12%) dogs. Surgical site infection was diagnosed in 48 of 275 (17.5%) dogs. Postoperative antibiotic therapy was used in 74 (64.9%) dogs, 62 (48.4%) dogs, and 32 (97.0%) dogs in the NLP, LP, and DLP groups, respectively. Dogs with NLP, LP, and DLP had postoperative infection rates of 24.5%, 13.3%, and 9.1%, respectively. There were no risk differences for the three groups (Holm-adjusted P > .05).

CONCLUSION

No difference in infection rates was detected between DLP, LP, or NLP for TPLO in these dogs weighing >50 kg.

CLINICAL SIGNIFICANCE

Fixation of TPLO with DLP in dogs weighing >50 kg does not seem to increase the risk of SSI compared with LP and NLP.

Impact of postoperative antibiotics on rates of infection and implant removal after tibial tuberosity advancement in 1,768 canine stifles

OBJECTIVE

To report infection rate, implant removal rate, and postoperative antibiotic therapy after tibial tuberosity advancement (TTA) in dogs.

STUDY DESIGN

Retrospective study.

ANIMALS

One thousand seven hundred sixty-eight stifles in 1,732 dogs.

METHODS

Medical records (January 2007-December 2011) of dogs treated with a TTA were reviewed. Cases were included if at least 1 year of postoperative follow-up was available and no additional procedures were performed on the stifle. Date of surgery, date of culture, culture and susceptibility results, postoperative antimicrobials used, and any implant removals were recorded. Use of postoperative antibiotics and implant removal were evaluated statistically for effect on infection occurrence and resolution.

RESULTS

Postoperative infections were diagnosed in 82 of 1,768 (4.6%) stifles. Implants were removed from 32 (39%) stifles, with plate and screw removal only in 23 (71.9%) stifles. The rate of infection did not differ between dogs with or without postoperative antibiotic therapy. However, dogs receiving postoperative antibiotic therapy were at risk for developing an oxacillin-resistant infection (P = .001). Oxacillin-resistant infections were associated with a requirement for implant removal to achieve resolution compared with other types of bacterial infections (P < .05).

CONCLUSION

No benefit was detected with the use of postoperative antibiotics after TTA in this population. Implant removal was infrequent, and the requirement for cage removal was not commonly required for infection resolution.

CLINICAL SIGNIFICANCE

This study does not provide evidence to support postoperative antibiotic therapy after TTA. Postoperative infection can be treated in most dogs without removal of the TTA cage.

A prospective, randomized, double-blinded, placebo-controlled clinical study on postoperative antibiotherapy in 150 arthroscopy-assisted tibial plateau leveling osteotomies in dogs

OBJECTIVE

To determine the influence of a 7-day course of postoperative antibiotherapy (cefpodoxime) on surgical site infections (SSI) after tibial plateau leveling osteotomy (TPLO).

STUDY DESIGN

Prospective, randomized, double-blinded, placebo-controlled clinical study.

SAMPLE POPULATION

One hundred fifty client-owned dogs, with consent.

METHODS

Dogs undergoing arthroscopy-assisted TPLO were randomly assigned to 1 of 2 groups, the placebo group receiving perioperative cefazolin and 7 days of placebo medication after surgery or the treatment group receiving perioperative cefazolin and 7 days of postoperative cefpodoxime. Twenty-seven factors were analyzed for association with SSI by using univariate analysis, Fisher's exact test, or Wilcoxon rank-sum test.

RESULTS

SSI rates did not differ (P = .34) between the placebo group (17%; 95% confidence level [CL] 7.94%-26.43%) and the treatment group (11% SSI; 95% CL 3.98%-18.88%). The probability that > 23% of dogs would benefit from postoperative antibiotherapy was less than 5%. The only association between the factors tested in this study and SSI involved the body weight (kg), with each 1 unit increase in kilogram weight increasing the odds of developing an SSI by 4.7%.

CONCLUSION

Although the wide CL may be consistent with a type II error, a 7-day course of cefpodoxime after arthroscopy-assisted TPLO did not influence postoperative SSI in the population tested here. In addition, only a small proportion of dogs would benefit from postoperative antibiotherapy under the conditions of our study.

CLINICAL SIGNIFICANCE

These results should prompt surgeons to reconsider systematic antibiotherapy after TPLO and justify additional studies to determine whether dogs predisposed to infection could benefit from such an approach.

Outcome and complications in dogs with appendicular primary bone tumors treated with stereotactic radiotherapy and concurrent surgical stabilization

OBJECTIVE

To document the outcome of dogs with appendicular primary bone tumors treated with stereotactic radiotherapy (SRT) and concurrent stabilization.

STUDY DESIGN

Multi-institutional retrospective case series.

ANIMALS

Eighteen dogs with presumptive or definitive diagnosis of appendicular osteosarcoma.

METHODS

Medical records of dogs with appendicular primary bone tumors treated with SRT and stabilization were reviewed for signalment, preoperative staging and diagnostics, radiation dose, stabilization method, and outcome.

RESULTS

The distal radius was affected in 13/18 cases. Osteosarcoma or sarcoma was confirmed cytologically or histologically in 15/18 cases. Seven dogs were diagnosed with a pathological fracture at the time of treatment, and 11 were considered at high risk for pathological fracture. Dogs received a single dose (n = 5) or 3 doses (n = 13) of SRT. Surgical stabilization was performed under the same anesthetic event as the final dose of SRT in 10 dogs. Stabilization was achieved with a bone plate (n = 15) or interlocking nail (n = 3). Seventeen dogs received adjuvant chemotherapy. Complications occurred in 16/17 dogs, 15/17 of those being considered major complications. Four dogs experienced more than one complication. Infection was the most common complication, diagnosed in 15/17 cases, and considered as a major complication in 13/15 cases. Postoperative fracture was recorded as a major complication in 3 cases. Nine dogs were amputated at a median of 152 days. The median survival time was 344 days.

CONCLUSION

Treatment of bone tumors with SRT and concurrent stabilization was associated with a prohibitively high complication rate in dogs. Alternative methods for limb salvage should be considered for dogs at risk for pathologic fracture.