Histomorphometric evaluation of MMP-9 and CD31 expression during healing under Negative Pressure Wound Therapy in dogs.

INTRODUCTION: The aim of the study was to evaluate the molecular and histological effects of negative pressure wound therapy (NPWT) on vascularisation in clinical cases of open wound treatment in dogs. Open wounds (n=10) were randomly assigned to one of two groups: NPWT treatment (n=5) or foam treatment (polyurethane-foam dressing, n=5). Wounds were matched based on age and underlying cause and analysed with respect to neovascularisation (CD31) and matrix proteinase changes (MMP-9). Histological slides were blinded and analysis was performed using automated histomorphometric software. Values determined at day zero after debridement were used as a reference and wound development at day six was evaluated using linear mixed models. Signalment, pre-treatment time and underlying cause were similar between groups. NPWT resulted in a highly significant increase of vascularisation (p.

INTRODUCTION: Le but de ce travail était de relever les effets moléculaires et histologiques de la thérapie des plaies par pression négative (NPWT) au cours du traitement de plaies ouvertes en clinique chez le chien. Des plaies ouvertes (n=10) ont été répartie de manière randomisée en deux groupes : NPWT (n=5) ou recouvrement au moyen d'un pansement en polyuréthane (n=5). Les plaies ont été appariées en tenant compte de leur âge ainsi que de leur cause et examinées quant à leur néo vascularisation (CD31) et aux variations de l'activité des métalloprotéases matricielles (MMP-9). L'appréciation des divers échantillons histologiques a été faite à l'aveugle, au moyen d'un logiciel d'histomorphométrie automatisé. Les valeurs obtenues au jour 0 après débridement servaient de référence pour l'évolution des plaies au jour 6, évolution analysée avec un modèle mixte. Le signalement, la durée du traitement préalable ainsi que les causes étaient comparables entre les groupes. La NPWT amenait, comparativement au contrôle, à une augmentation significative de la vascularisation (p.

Preventive incisional negative pressure wound therapy (Prevena) for an at-risk-surgical closure in a female Rottweiler.

This case report describes a combination of negative pressure-wound-therapy (NPWT) and NPWT assisted incision management after resection of an abscess located at the right thoracic wall in a Rottweiler. The patient had a history of severe incisional complications after surgical interventions performed in the past, including repeated episodes of wound dehiscence, major skin necrosis and infection with and without a multiresistant strain of Staphylococcus aureus and several episodes of open wound management with healing rates between months and a year. Wound closure after resection of the mass was performed as a staged procedure. After two days of open NPWT the wound was primarily closed and a preventive incisional vacuum assisted therapy (CI-NPWT) was started for 7 days. The patient was discharged during therapy with the portable device in place. The Unit was removed at day 7 post wound closure, suture removal followed at day 10. Wound healing was uneventful and no major complications occurred at a follow up time of 8 months. This is the first description of closed incisional negative pressure wound therapy in the dog.

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.

[Prospective analysis of risk factors for perioperative infections in clean and clean-contaminated surgeries in dogs and cats with special reference to perioperative and postoperative antibiotic use]. / Prospektive Analyse von Risikofaktoren für perioperative Infektionen bei sauberen und sauber-kontaminierten Eingriffen bei Hund und Katze unter besonderer Berücksichtigung des perioperativen und postoperativen Antibiotikaeinsatzes.

INTRODUCTION: With every surgical procedure there is a risk of postoperative infection (surgical site infection = SSI). This risk of infection can be influenced by various factors, including perioperative antibiotic prophylaxis. In terms of antibiotic stewardship, antibiotics should only be used if there is a proven benefit for the patient. However, this advantage has not yet been conclusively proven, especially for clean and clean-contaminated surgeries. The aim of our study was to document various relevant influencing factors on the infection rate after clean and clean-contaminated surgeries in dogs and cats. In particular, it was documented to what extent a reduced use of antibiotics affects the infection rate in the context of all influencing factors. Over a period of eleven months, 807 clean and clean-contaminated surgeries in dogs and cats were prospectively analyzed with possible influencing factors (gender, ASA classification, underlying endocrinological diseases, duration of anesthesia, duration of surgery, type of surgery, perioperative antibiotic prophylaxis (POA), duration of hospitalization) affecting the infection rate. After surgery all cases were followed up either 30 or 90 days, if implants were used. The effect of the various factors was evaluated using multivariable logistic regression analysis. SSI was detected in 25/664 clean and 10/143 clean-contaminated surgeries. Longer hospitalization, without antimicrobial prophylaxis, and male animals had a significantly higher risk of SSI. In clean surgeries, SSI occurred in 2,3 % of all cases with POA and 5,3 % without POA. The SSI in clean-contaminated was 3,6 % with POA and 9 % without. This difference resulted mainly from the results of osteosynthesis, gastrointestinal and skin surgeries. However, other types of surgeries, such as castrations, neurological interventions, abdominal and thoracic surgeries, and surgeries in the head and neck region, showed comparable infection rates with and without POA.

INTRODUCTION: Toute intervention chirurgicale comporte un risque d'infection postopératoire (infection du site opératoire = ISO). Ce risque d'infection peut être influencé par différents facteurs, dont l'antibioprophylaxie périopératoire. En termes de gestion responsable des antibiotiques, les antibiotiques ne devraient être utilisés que s'il existe un avantage prouvé pour le patient. Cependant, cet avantage n'a pas encore été prouvé de manière concluante, en particulier pour les chirurgies propres et propres-contaminées. L'objectif de notre étude était de documenter divers facteurs d'influence pertinents sur le taux d'infection après des chirurgies propres et propres-contaminées chez les chiens et les chats. Nous avons en particulier cherché à savoir dans quelle mesure une utilisation réduite des antibiotiques affecte le taux d'infection en tenant compte de tous les facteurs d'influence. Sur une période de onze mois, 807 chirurgies propres et contaminées chez des chiens et des chats ont été analysées prospectivement avec les facteurs d'influence possibles (sexe, classification ASA, maladies endocrinologiques sous-jacentes, durée de l'anesthésie, durée de la chirurgie, type de chirurgie, prophylaxie antibiotique périopératoire (POA), durée de l'hospitalisation) affectant le taux d'infection. Après la chirurgie, tous les cas ont été suivis durant soit 30 soit90 jours si des implants avaient été utilisés. L'effet des différents facteurs a été évalué par une analyse de régression logistique multivariable. Des ISO ont été détectées dans 25/664 chirurgies propres et 10/143 chirurgies contaminées propres. Une hospitalisation plus longue sans prophylaxie antimicrobienne ainsi que les animaux mâles présentaient un risque significativement plus élevé d'ISO. Dans les chirurgies propres, les ISO sont survenues dans 2,3 % des cas avec POA et 5,3 % sans POA. Dans les opérations propres-contaminées, les ISO étaient de 3,6 % avec POA et de 9 % sans POA. Cette différence était principalement due aux résultats des ostéosynthèses, des chirurgies gastro-intestinales et cutanées. En revanbche, d'autres types de chirurgies, comme les castrations, les interventions neurologiques, les chirurgies abdominales et thoraciques et les chirurgies de la tête et du cou ont montré des taux d'infection comparables avec et sans POA.

Near-infrared fluorescent image-guided lymph node dissection compared with locoregional lymphadenectomies in dogs with mast cell tumours.

OBJECTIVES: Near-infrared fluorescent imaging has been described for intraoperative mapping of the draining lymph nodes in human cancer and canine oral tumours. The aim of this study was to retrospectively describe the results of lymphadenectomies in dogs with mast cell tumours treated either by standard unguided locoregional lymph node dissection or near-infrared fluorescent image-guided lymph node dissection. METHODS: Medical records between 2012 and 2020 were reviewed for dogs that were presented for surgical resection of mast cell tumours with concurrent lymphadenectomy either with (near-infrared fluorescent image-guided lymph node dissection) or without near-infrared fluorescence image guidance (lymph node dissection). The number and location of lymph nodes planned for surgical dissection and actually dissected nodes, presence of metastases and perioperative complications were recorded. RESULTS: Thirty-five patients underwent near-infrared fluorescent image-guided lymph node dissection, and 43 lymph node dissections. The number of nodes preoperatively planned for resection were 70 and 68, respectively. Fifty-eight of those (83%) were identified during near-infrared fluorescent image-guided lymph node dissection procedures, compared with 50 (74%) during lymph node dissection. near-infrared fluorescent image-guided lymph node dissection resulted in resection of additional fluorescent nodes not corresponding to locoregional nodes in 15 of 35 dogs. Using near-infrared fluorescent image-guided lymph node dissection, we identified at least one metastatic node in 68% of dogs (24 of 35) compared with 33% (14 of 43) when lymph node dissection was used without imaging. No complications related to near-infrared fluorescent imaging were reported. CLINICAL SIGNIFICANCE: The present study suggests that near-infrared imaging is a promising technique for intraoperative detection of the draining lymph nodes in dogs with mast cell tumours. Further validation of the technique is required to assess if near-infrared fluorescent imaging can detect the true sentinel lymph node.

Outcome of superficial brachial axial pattern flaps used to close skin defects in dogs: 16 cases (1996-2019).

OBJECTIVES: To report the complication rate, type of complications and outcome of the superficial brachial axial pattern flap when used for closure of skin defects in dogs. MATERIALS AND METHODS: Medical records of dogs treated with a superficial brachial axial pattern flap for closure of a skin defect were reviewed. Information regarding signalment, reason for axial pattern flap use, skin flap size, flap healing, postoperative complications and need for revision surgery was collected. RESULTS: Sixteen dogs were included in the study. Indications for the superficial brachial axial pattern flap included closure following tumour removal (15/16, 94%) and management of a non-healing wound on the olecranon (1/16, 6%). Postoperative complications occurred in all dogs and included partial dehiscence (7/16, 44%), partial flap necrosis (6/16. 38%), seroma formation (5/16, 31%), flap oedema (3/16, 19%) and complete flap necrosis (2/16, 13%). Eight flaps (50%) healed without open wound management or additional surgery. Five dogs required open wound management without additional surgery, and three dogs (19%) required revision surgery. CLINICAL SIGNIFICANCE: Use of the superficial brachial axial pattern flap was associated with a high rate of complications. Most complications were managed without additional surgery and all wounds eventually healed, in some cases after prolonged open wound management.

In vitro evaluation of the decontamination effect of cold atmospheric argon plasma on selected bacteria frequently encountered in small animal bite injuries.

Beneficial effects of cold atmospheric argon plasma (CAAP) on wound healing and its capacity for bacterial decontamination has recently been documented. First, in vivo studies in small animals did not prove any decontamination effect in canine bite wounds. The present study evaluated the overall decontamination effect of CAAP for different bacteria frequently encountered in canine bite wounds with respect to growth phase, initial bacteria concentration and treatment duration. Standard strains of Escherichia (E.) coli, Staphylococcus (S.) pseudintermedius, S. aureus, Streptococcus (S.) canis, Pseudomonas (P.) aeruginosa and Pasteurella multocida were investigated. To evaluate the influence of the bacterial growth phase, each bacterium was incubated for three and eight hours, before CAAP treatment. Three different bacterial concentrations were created per bacterium and growth phase, and were exposed to CAAP for 30 s, 1 min and 2 min. CAAP treatment resulted in acceptable decontamination rates (range 98.9-99.9%) in all bacteria species in vitro; however, differences in susceptibility were detected. Decontamination rate was mainly influenced by initial bacterial concentration and treatment time. Growth phase only influenced decontamination in S. pseudintermedius. Treatment time significantly (P < .05) correlated with the decontamination rate in E. coli, S. canis and S. aureus, with an exposure time of 2 min being most effective. Initial bacterial concentration significantly (P < .05) influenced decontamination in Pasteurella multocida and P. aeruginosa, in which treatment time was not as important. CAAP exerts effective antibacterial activity against the tested bacteria strains in vitro, with species specific effects of treatment time, growth phase and concentration.

Long-term clinical outcomes following surgery for spontaneous pneumothorax caused by pulmonary blebs and bullae in dogs - a multicentre (AVSTS Research Cooperative) retrospective study.

OBJECTIVES: To report the clinical characteristics and recurrence rate of spontaneous pneumothorax secondary to pulmonary blebs and bullae following surgical management in a large cohort of dogs. To explore potential risk factors for recurrence and describe outcome. MATERIALS AND METHODS: Medical records were retrospectively reviewed for cases with spontaneous pneumothorax managed surgically between 2000 and 2017. Signalment, clinical presentation, diagnostic imaging, surgery, histopathology findings and patient outcomes were recorded. Follow-up was performed via patient records and telephone contact. RESULTS: Records of 120 dogs with surgically treated pneumothorax were identified and reviewed, with 99 cases appropriate for exploratory statistical analysis. Median follow-up was 850 days (range: 9-5105 days). Two- and 5-year survival rates were 88.4% and 83.5%, respectively. There was recurrence in 14 of 99 dogs (14.1%) with adequate follow-up, with a median time to recurrence of 25 days (1-1719 days). Univariable Cox regression analysis suggested increased risk for recurrence in giant breeds (hazard ratio = 11.05, 95% confidence interval: 2.82-43.35) and with increasing bodyweight (HR = 1.04, 95% confidence interval: 1.00-1.09). Of 14 dogs with recurrence, six were euthanased, two died of causes related to pneumothorax and six underwent further treatment, of which five were resolved. CLINICAL SIGNIFICANCE: Long-term survival for dogs with surgically managed spontaneous pneumothorax was good and associated with a low risk of recurrence. Giant breed dogs and increased bodyweight were the only variables identified as possible risk factors for recurrence. The outcome for dogs with recurrence undergoing a second intervention was also favourable.

Comparison of two beta-tricalcium phosphate composite grafts used for reconstruction of mandibular critical size bone defects.

OBJECTIVE: The aim was to compare osseointegration of blood perfused beta-tricalcium phosphate cylinders (beta-TCPB) with similar composites that were additionally loaded with cancellous bone and bone marrow (beta-TCPB/BM/CB) for mandibular reconstruction. METHODS: Twelve German Black-Headed sheep with an average weight of 72.5 +/- 10 kg underwent segmental resection of the right hemi-mandible. The animals that were assigned to group A (n = 6) were reconstructed using beta-TCPB while the sheep that were assigned to group B received beta-TCPB/BM/CB grafts. Tissue quality was histologically assessed and bone-, scaffold-, cartilage- and fibrous-tissue area were estimated using semiautomated histomorphometrical software. RESULTS: Composite grafts that were loaded with bone marrow and cancellous bone (beta-TCPB/BM/CB) exhibited significant (p<0.01) higher amounts of bone formation than beta-TCPB. The patients that were assigned to group B achieved defect union and a high grade of bone maturation. Residual ceramic remnants were rare and disconnected. Bone maturity within group A was inferior and none of the specimens showed defect union. The defect centre was still occupied by a ceramic core. CLINICAL SIGNIFICANCE: Bone and bone marrow augmented beta-tricalcium phosphate composites may qualify as a promising alternative to autograft bone for mandibular reconstruction in human and veterinary medicine.

Comparison of polyhexanide, cold atmospheric plasma and saline in the treatment of canine bite wounds.

OBJECTIVES: To compare the efficacy of polyhexanide, cold argon plasma and saline in reducing bacterial bio-burden in dog bite wounds. MATERIALS AND METHODS: Prospective blinded randomised clinical trial. Dogs were randomly assigned to one of the treatment groups by lottery and bacterial cultures obtained before and after treatment were compared. Bite wounds were surgically debrided and treated with polyhexanide, cold argon plasma or saline lavage. All wounds were cultured three times: directly after debridement, directly after prelavage with 2 mL/cm2 (saline in the saline and cold argon plasma group, or polyhexanide) and following the definitive lavage. Data were analysed using a generalised linear model for ordinal data. RESULTS: A total of 85 dogs were enrolled in this study (polyhexanide n=29, cold argon plasma n=28, saline n=28). Positive bacterial culture results after debridement were obtained in 53/85 (62.3%) wounds. Polyhexanide and saline lavage significantly reduced the bio-burden, while cold argon plasma treatment did not. This effect was evident after prelavage when polyhexanide performed significantly better than saline and cold argon plasma as well as after final treatment. No significant differences were detected after prelavage or main treatment between saline and cold argon plasma. CLINICAL SIGNIFICANCE: Polyhexanide lavage achieved the best immediate and ultimate decontamination of bite wounds.

[Negative Pressure Wound Therapy (NPWT) in small animal medicine. Mechanisms of action, applications and indications]. / Vakuumassistierte Wundbehandlung (Negative Pressure Wound Therapy, NPWT) in der Kleintiermedizin. Wirkweise, Anwendung und Indikationen.

The treatment of open wounds is a daily challenge in veterinary medicine. During the past years, a special treatment option, the Negative Pressure Wound Therapy (NPWT), has been developed. Usage of this therapy significantly increases the healing rate of open wounds as well as free skin grafts in small animals. This review describes the mechanisms of action, indications as well as the known complications associated with this therapy.

Assessment of wound bio-burden and prevalence of multi-drug resistant bacteria during open wound management.

OBJECTIVE: To describe the bacterial bio-burden of open-treated wounds and make comparisons with bite wounds. DESIGN: Retrospective multicentre study. SAMPLE: Microbial culture between 2011 and 2013 from open-treated wounds in dogs and cats (initiation of therapy n=88, follow-up n=52) were compared to those from bite wounds (n=184). PROCEDURES: Bacteria were identified and tested for antibiotic susceptibility by two accredited laboratories. RESULTS: In total, 77/88 (88%) of open-treated wounds yielded positive bacterial cultures at the beginning of treatment, decreasing to 27/52 (52%) during treatment. Upon initial evaluation, 42/88 (48 %) of open-treated wounds were considered infected with multi-drug-resistant bacteria, with a drop to 22/52 (41%) during therapy. Bite wounds yielded fewer positive cultures 88/184 (48%) with only 11/182 (6%) being affected by multi-drug-resistant bacteria. Bacteria found most commonly in open-treated wounds were Enterococcus subspecies, Escherichia coli, Staphylococcus pseudintermedius and Pseudomonas aeruginosa. CONCLUSION: The bacterial populations of open-treated wounds differed markedly from the bite wounds. The high incidence of multi-drug-resistant strains in open wounds highlights the need for alternatives to antibiotics.

Necrotising fasciitis in a domestic shorthair cat--negative pressure wound therapy assisted debridement and reconstruction.

A 10-year-old, domestic shorthair cat was presented for acute lameness of the left forelimb accompanied by severe pain, swelling, skin necrosis, malodorous discharge and pyrexia. Following a presumptive diagnosis of necrotising fasciitis aggressive surgical debridement of the affected soft tissues of the antebrachium and negative pressure wound treatment of the open defect were performed. Surgical findings supported the tentative diagnosis of necrotising fasciitis and Streptococcus canis was isolated from the wound. A free skin graft was performed 29 days after admission, and augmented by 3 days of negative pressure wound therapy to facilitate graft incorporation. Healing was achieved without complications and no functional or aesthetic abnormalities remained.

Negative pressure wound therapy with instillation for body wall reconstruction using an artificial mesh in a Dachshund.

CASE REPORT: A 4-year-old spayed female Dachshund was presented in shock, displaying multiple haematomas and puncture wounds along the left abdominal wall and ventral aspect of the abdomen after being attacked by another dog. A defect of the left lateral body wall was palpated. Surgery revealed a massive body wall defect and concurrent injury of the intestines. Surgical debridement was performed and the injured portion of the jejunum was resected. The abdominal wall was reconstructed using a polypropylene mesh. Negative pressure wound therapy (NPWT) with instillation of 0.04% polyhexanide (-125 mmHg, instillation interval of 2 h, duration 20 min) was started. Microbial culture after reconstruction of the defect and before application of the NPWTi dressing revealed multiresistant Staphylococcus pseudintermedius. The NPWT dressing was changed on days 2, 5 and 7. Microbial cultures obtained at the first two dressing changes were negative. Therapy was well tolerated and the mesh was completely covered by granulation tissue after 10 days, when the wound was surgically closed. CONCLUSION: Bite wounds frequently result in massive, contaminated defects with impaired perfusion, and reconstruction using foreign material carries the risk of biofilm formation and infection. Instillation therapy may provide an alternative for bacterial clearance and fast integration of the mesh.

Negative pressure wound therapy, silver coated foam dressing and conventional bandages in open wound treatment in dogs. A retrospective comparison of 50 paired cases.

OBJECTIVES: To evaluate negative pressure wound therapy (NPWT) for treatment of complicated wounds in dogs. STUDY TYPE: Retrospective multicentre study. MATERIALS AND METHODS: Dogs (n = 50) undergoing open wound treatment were classified according to treatment method used: bandage (Group A, n = 7), NPWT (Group B, n = 18), and foam dressing (Group C, n = 25). Pairs of patients matched based on wound conformation, localization, and underlying cause were compared between Group A and C (n = 7 pairs) and between groups B and C (n = 18 pairs) in terms of duration of previous treatment, time to closure, and complications. RESULTS: Signalment, antibiotic medications, antiseptic treatment, and bacterial status of wounds were comparable between groups. The duration of previous treatment was significantly higher in patients assigned to Group B (p = 0.04) compared to Group C, while no significant difference was found between groups A and B. Total time to wound closure was significantly shorter in Group C compared to Group A (p = 0.02) and in Group B compared to Group C (p = 0.003). Wounds treated with NPWT suffered significantly less complications (p = 0.008) and were significantly less septic during treatment (p = 0.016) than wounds treated with a foam dressing. CONCLUSION: This study shows that time to healing was halved in NPWT treated patients compared to foam dressing treated patients, which in turn healed faster than patients treated with conventional bandage, underlining the value of NPWT therapy for the treatment of complicated wounds.

[Necrotizing fasciitis: a review]. / Nekrotisierende Fasziitis: ein Überblick.

Necrotizing fasciitis is a rare, fatal bacterial infection associated with a high morbidity in humans (25-40%) that is frequently underdiagnosed in veterinary patients. Rapid diagnosis of the disease is mandatory because the time to surgical intervention and the degree of debridement are the only predictive variables that influence a successful outcome. Specific clinical signs are not always present, which makes an accurate diagnosis difficult. Despite differences in microbiological etiology, the disease pattern is comparable between canine, feline and human cases. Based on the current literature and our own experience, this article presents a review of the etiology, pathophysiology, diagnostic strategies, therapy and prognosis of the disease.

Feline osteochondromatosis in a FELV-negative European shorthair cat.

OBJECTIVE: To report palliative treatment in a case of multifocal feline osteochondromatosis in a feline leukaemia virus (FeLV) negative European shorthair cat. CASE: A 6-year-old spayed female European shorthair cat was presented because of a right forelimb lameness caused by an osteochondromatous lesion which had trapped tendons, vessels and nerves of the antebrachium. Several other lesions were present which did not cause the animal discomfort. The cat was tested negative for FeLV. Palliative surgical removal of the mass was performed, resulting in a marked improvement of mobility with no local recurrence. The cat developed a non-regenerative anaemia after surgery, however the underlying cause was not identified upon request of the owner. Overall survival after surgery was only 2 months. The cat was then euthanised due to severe progression of the anaemia. CONCLUSION: Palliative surgical removal of osteochondromas may result in local improvement. However, owners need to be aware that it does not increase overall survival and that the prognosis is poor. Infection with FeLV is not necessarily associated with such lesions.

Prefabrication of vascularized bioartificial bone grafts in vivo for segmental mandibular reconstruction: experimental pilot study in sheep and first clinical application.

The key elements for bioartificial bone formation in 3D matrices are large numbers of osteogenic cells and supplies of oxygen and nutrition. Vascularization becomes more important with the increasing size and complexity of seeded scaffolds required for clinical application in reconstructive craniomaxillofacial surgery. Prefabrication of vascularized bioartificial bone grafts in vivo might be an alternative to in vitro tissue engineering techniques. Two cylindrical beta-TCP-scaffolds (25 mm long) were intraoperatively filled with autogenous bone marrow from the iliac crest for cell loading and implanted into the latissimus dorsi muscle in 12 sheep. To determine the effect of axial perfusion, one scaffold in each sheep was surgically supplied with a central vascular bundle. Sheep were killed 3 months after surgery. Histomorphometric analysis showed autogenous bone marrow from the iliac crest was an effective source of osteogenic cells and growth factors, inducing considerable ectopic bone growth in all implanted scaffolds. Bone growth, ceramic resorption and angiogenesis increased significantly with axial perfusion. The results encourage the application of prefabricated bioartificial bone for segmental mandibular reconstruction in man. In clinical practice, vascularized bioartificial bone grafts could change the principles of bone transplantation with minimal donor site morbidity and no shape or volume limitations.

Comparison of computed tomography and microradiography for graft evaluation after reconstruction of critical size bone defects using beta-tricalcium phosphate.

INTRODUCTION: The aim of the study was to evaluate the accuracy of computed tomography (CT) for in vivo follow up after mandibular reconstruction. MATERIAL AND METHODS: Unilateral mandibular defects were surgically created in ten sheep and either reconstructed using blood soaked beta-tricalcium phosphate (beta-TCP) cylinders (group A, n=5) or blood soaked beta-TCP cylinders that were additionally loaded with autologous bone marrow (group B, n=5). The two graft designs resulted in different stages of graft ossification representative of different stages of healing. CT datasets were fused with microradiographs and measurements of ceramic area based on both methods were compared. RESULTS: Two animals (groups A (n=1) and B (n=1)) presented infection and graft dislocation that was visible on CT and were excluded from statistical evaluation. Group A grafts underwent moderate degradation (53.55%+/-9.7) and incomplete bony incorporation representing an intermediate state of healing while ceramic grafts within group B developed a high grade of osseointegration and degradation (94.2%+/-3.3) consistent with progressive healing. Statistical comparison of measurements based on both methods revealed a significant bias (p<0.05) and a non-significant variance for group A and a significant variance (p<0.05) and non-significant bias for group B. CONCLUSION: Our results indicate that conventional CT is not suitable to objectively evaluate ossification and degradation of a beta-TCP graft in vivo and further attempts to improve clinical visualization of beta-TCP need to be undertaken.