Free microvascular epiphyseal-plate transplantation. An experimental study in dogs

To evaluate the feasibility of transplanting vascularized epiphyseal plates while maintaining normal growth in the recipient site, twenty-two puppies from known, large breeds were divided into one control and three experimental groups of four animals each and one long-term group of six animals. The control group underwent insertion of a radiopaque marker in the fibular metaphysis bilaterally, and, in addition, a fibular osteotomy was performed on one side. In the experimental groups, a fibular switch was carried out, selecting one fibula as a vascularized graft and the other as a non-vascularized graft. Both the controls and the experimental groups were evaluated using serial roentgenograms, histological examination, fluorescent bone-labeling, and microangiography. One week, six weeks, three months, and seven months postoperatively, animals from each group were killed. Continuous growth was observed in the vascularized epiphyseal transplants and in the controls, with no statistical difference noted, whereas the non-vascularized transplants exhibited considerably less or no growth. Vascularized transplants demonstrated an average 21.2-millimeter increase in length while non-vascularized transplants showed a 6.6-millimeter increase. Histological examination, fluorochrome bone-labeling, and microangiography confirmed the continued viability of the vascularized epiphyseal transplants in contrast to the non-vascularized transplants.     

Free skeletal muscle transplantation to an infarction area: An experimental study in the dog.

In plastic surgery, free skeletal muscle flaps are used for treatment of non-healing injuries like chronic osteitis or radiation ulcers. We wanted to evaluate if the neoangiogenesis induced by these flaps can also constitute a method for revascularization in ischemic heart disease. In diffuse small vessel coronary heart disease, patients are not suitable for bypass surgery because it is impossible to create a microanastomosis with the coronary artery. As an alternative, a free striated muscle flap, transplanted onto the heart, can constitute a source of neovessels. With the induction of extra-intracardial collaterals that develop within 4 weeks after transplantation of the flap, a new surgical approach may be offered to those patients. Our experimental work was performed with 20 dogs. In these, a myocardial infarction of the anterior wall was selectively produced using the Judkins-technique (Radiology 89: 815–824, 1967) for injection of Sephadex-microspheres. Four weeks later a free pectoralis muscle flap was transplanted onto the anterior wall of the heart. Arterial blood supply was achieved with an anastomosis with the internal mammary artery. The venous flow was directed into the right atrium. Four to eight weeks after surgery, the patency of the anastomosis was studied by angiography, showing patency in almost all surviving animals. Histological examination of the hearts revealed a prominent vascular network penetrating into the underlying myocardium. Corrosion cast preparations, as well as a postmortem angiography, showed even further penetration of the neovessels into the uninjured parts of the myocardium. Thus, myocardial revascularization may be achieved by transplantation of a skeletal muscle onto the heart. © 1993 Wiley-Liss Inc.     

An approach to ABO-incompatible liver transplantation in children.

Survival in ABO-incompatible (ABO-I) liver transplantation has been reported to be between 40% and 60%. Management techniques have included routine immunosuppression as well as prophylactic antilymphoblast globulin, pre- and posttransplant plasmapheresis (PLPH), and splenectomy. Over a 6-year period, 155 orthotopic liver transplants were performed in 139 pediatric patients. Seven children received an ABO-I allograft. In the latter transplants, immunosuppression consisted of triple-drug therapy (cyclosporine A, prednisone, and azathioprine) along with prospective double-volume PLPH for ABO titers (IgA and IgM) greater than or equal to 1:8. Splenectomy was not performed on any patient. One patient was refractory to PLPH and was treated with a hemofiltration system using an immunoadsorption cartridge with synthetic A group antigen. The overall survival for patients receiving ABO-I allografts was 57% (4/7), with a 67% (4/6) graft survival in those patients treated with PLPH. The graft survival for patients treated with prospective PLPH and MALG was 60% (3/5). There was a 60% incidence of rejection in those patients treated with prospective PLPH and these episodes were all mild (steroid bolus only). While ABO-I transplantation is a reasonable option in the emergency setting, further study is necessary before it should be routinely used to increase the general donor organ pool in pediatric liver transplantation.     

Free functional muscle transplantation for facial reanimation: experimental comparison between the one- and two-stage approach.

To investigate functional results of either one- or two-staged free muscle transplantation the scutuloauricularis model in the New Zealand white rabbit was used. Thirty rabbits were allocated to two groups with 15 animals each. In Group 1 (one-stage approach) peroneus brevis (PB) was harvested as a free muscle graft with a 7cm long motor branch. The graft was positioned instead of right scutuloauricularis (SCUT) and its vascular supply microsurgically re-established. The motor branch was transferred to the contralateral side and its proximal end coapted to the cut facial motor branch to left SCUT. Before nerve coaptation biopsies were harvested from the cut motor branch for morphological analysis. In Group 2 (two-stage approach) a 7cm long saphenous nerve graft was taken and coapted to the cut motor branch of SCUT and crossed over to the contralateral side. Nerve specimens from the cut motor branch were taken. Eight months later the free transplantation of PB was performed and its motor branch coapted to the distal end of the cross-over nerve graft. After a total time period of 13 months the final experiments were carried out in each group. Maximal tetanic tensions in reinnervated PB were measured and biopsies of muscle grafts together with nerve biopsies from the distal part of the motor branch were harvested for morphological analysis. Muscle grafts of Group 1 revealed tetanic tension values of 12.5N (SD 3.1) in comparison to 10.6N (SD 3.5) obtained in Group 2. This difference was not statistically significant (p=0.303). In Group 1, the amount of regenerated nerve fibers counted at the distal motor branch site (mean: 2798, SD 1242) was significantly higher (p=0.008) than in Group 2 (mean: 1138, SD 1004). Muscle graft morphology revealed significantly less Type I fibers (p=0.016) and more Type IIb/d fibers (p=0.011) in Group 1 compared to Group 2. However, the overall amount of perimysial connective tissue showed no significant difference in both groups (p=0.478). Free muscle transplantation in a one-stage approach offers similar functional results in comparison to the two-stage approach. Although muscle grafts of the one-stage transplantation underwent a longer period of denervation similar contents of perimysial connective tissue could be observed.     

Acute appendicitis in the rabbit. An experimental study

With the purpose of devising an experimental model of acute appendicitis, the vermiform appendix in five rabbits was lightly compressed with a specially designed metal clamp, and in five others it was firmly ligated proximally. Based on these experiments, a final model was evolved, with a firm ligature midway on the vermiform process. This model was tested in 15 rabbits and proved to be reliable in provoking acute inflammation in one part, while the rest of the appendix remained unaffected. The literature is reviewed.     

Selective lymphoid irradiation. I. An approach to transplantation.

The kinetics, distribution, and radiobiologic effects of palladium (Pd)-109-hematoporphyrin were determined in the rat. In addition, we studied the effect on rat heart allograft survival of Pd-109-hematoporphyrin, with and without antilymphocyte serum (ALS). A single sublethal dose of Pd-109-hematoporphyrin (up to 36 muCi/kg) resulted in the following: predominant concentration in lymphoid tissue and proximal bone marrow, complete central and proximal bone marrow ablation with preservation of distal bone marrow, massive depletion of lymphocytes from lymph nodes and spleen, an 80% reduction in peripheral blood lymphocytes which was completed by the addition of ALS, full recovery of lymphoid tissue and blood cellularity within 60 days of administration of radionuclide, and a 100% animal survival rate. This method of selective lymphoid irradiation (SLI) prolongs indefinitely Fisher cardiac allografts in Lewis recipients and significantly prolongs cardiac allograft survival across major histocompatibility barries (ACI to Lewis or to Fisher). Specific tolerance to donor strains was demonstrated by the acceptance of Fisher skin by Lewis recipients carrying 150-day-old Fisher hearts. Third party (ACI) skin allografts were rapidly rejected by the same animals. Further studies of SLI in larger animals are required to determine the optimal safe dose of SLI in man.     

Free vascularized nerve grafts: an experimental study in the rabbit

An experimental animal model of a vascularized graft is presented as an alternative to recover faster function. The technique is described and the model compared to a conventional graft in the sciatic nerve of a rabbit. Results are evaluated with histological studies and quantified using a computer to measure the thickness of the myelin sheath as a correspondence factor of regeneration. Results showed a more favorable regeneration when a vascularized graft was used.     

Free tunica vaginalis patch in urethroplasty. An experimental study

The management of urethral strictures is a challenge for surgery. In the present study the value of tunica vaginalis tissue for urethroplasty was investigated. 30 male rabbits were divided into two groups. In group I (11 animals) a urethral defect was covered with a tunica vaginalis patch (n = 6) or was left uncovered (n = 5). In group II (19 animals) a preoperative urethral stricture was induced by electrocoagulation through a urethroscope. The strictured urethra was plastied with tunica vaginalis (n = 9) or preputial (n = 10) patches. The results were analyzed after a period of 2 weeks to 5 months with radiographic, macroscopic and microscopic methods. The tunica vaginalis graft showed its superiority over the preputial graft: only 1 postoperative short stricture from 15 plasties (6 normal and 9 strictured urethrae) was found in the plastied group, whereas 2 strictures from 10 plasties were seen in the preputial patch group. In the urethral defect group, strictures were seen in 2 of 5 animals. The mesenchymal tunica vaginalis epithelium was covered with thin transitiocellular-like epithelium resembling transitiocellular layers. The present study supports the earlier findings on the use of tunica vaginalis tissue in urethroplasty.     

Eudaimonia: An Aristotelian approach to transplantation

Despite extraordinary achievements in over the past 20 years, the field of transplantation remains hindered by relatively narrow metrics for success. Eudaimonia is an Aristotelian concept that refers to flourishing, or achieving the best conditions possible, in every sense. The vast amounts of patient data that are collected throughout the transplant care continuum, ranging from social determinants of health to genomic profiles and patient-reported outcomes, afford us unprecedented opportunity to enhance our definition of success for our transplant patients. We must engage the technologies available for data integration and analysis and apply them in an insightful way, such that our clinical practice evolves beyond patient and graft survival and toward a more comprehensive state of wellness.     

超声造影对移植肝局灶性病变的鉴别诊断价值

目的探讨超声造影对移植肝内局灶性病变的鉴别诊断价值。方法对67例肝移植术后确诊有移植肝内局灶性病变的患者进行超声造影检查,观察不同病变在动脉期、门静脉期和延迟期3个时相的造影剂灌注模式。以延迟期仍保持高增强或等增强或造影中始终无增强判定为良性病变,以延迟期消退为低增强或无增强判定为恶性病变,计算超声造影诊断良性病变与恶性病变的敏感度与假阴性率。结果与良性病变比较,在动脉期表现为高增强或等增强的病灶中,恶性病变在门静脉期或延迟期有显著的增强消退倾向(P0.01)。超声造影诊断良性病变的敏感度为90%(19/21),假阴性率为10%(2/21),2例假阴性均为肝脓肿;诊断恶性病变的敏感度为100%(46/46)。结论超声造影对移植肝内局灶性病变具有较高的鉴别诊断价值,有助于区别良、恶性病变。     

Free revascularised periosteum transplantation: an experimental study

Two different types of revascularised periosteal graft were used to bridge an experimental bone defect and compared with control groups. Revascularised tibial periosteal grafts completely filled the defect with new bone, whereas revascularised rib periosteal grafts failed to do so.     

Stapled versus hand-sewn vascular anastomoses. An experimental study in the rabbit

OBJECTIVE: Narrowing of vascular anastomoses is a frequently encountered surgical problem, with intimal hyperplasia being one of its most important causes. The aim of the present study was to compare in a rabbit model 'manual' (hand-sewn) with 'stapled' anastomoses (using a staple device) with respect to occurrence and severity of intimal hyperplasia. MATERIALS AND METHODS: Twenty-four male rabbits (mean weight 2,849 g) were randomly allocated to one of two groups (n = 12). An end-to-end anastomosis of the left femoral artery was performed in all animals under general anesthesia. The anastomosis was hand sewn in group 1, while a vascular closure stapler (VCS) was used in group 2. Both anastomotic time and total operation time were recorded. After 28 days, the rabbits were sacrificed. The femoral artery of operated and nonoperated sides were removed and prepared for anatomopathological examination. The I/M ratio (= difference between tunica intima and tunica media) was determined on hematoxylin-eosin stained slides. All results were analyzed using Student's t test. RESULTS: Mean anastomotic times were 25 +/- 7 min for the 'manual' group and 17 +/- 9 min for the 'stapled' group (p = 0.02). There was no significant difference in the total operation time (55 +/- 15 vs. 41 +/- 18 min, p = 0.057). All animals survived the anastomosis procedure. In the group of 'manual' anastomosis, morbidity was significantly higher. At the moment of sacrifice, all anastomoses were patent. There was no difference in the I/M ratio between the groups. CONCLUSIONS: The use of VCS is a promising alternative to hand-sewn anastomoses. It takes less time to perform a stapled anastomosis, the technique has a shorter learning period and morbidity seems to be lower when vascular anastomoses are applied with the VCS in this rabbit model.     

Meniscus transplantation using a cryopreserved allograft--an experimental study in the rabbit

In twenty rabbits with completion of bone growth, the medial meniscus was replaced with an allograft meniscus that had been preserved at -80 degrees C for 6 to 14 days. As a control, the medial meniscus was removed and reattached without cryopreservation in 14 rabbits. Replaced menisci were examined histologically and microangiographically. Allografted menisci were found to attach to the capsule at 4 weeks. However, the attachments of the anterior and posterior horns were not stable in the majority of rabbits, because the nylon thread for anchoring was broken in these cases. There was osteophyte formation on the medial tibial plateau and the medial femoral condyle. Histological examinations revealed proliferation of vascularized synovial tissue along the meniscal surface and invasion of para-meniscal connective tissue into the meniscal substance. Chondrocytes showed regeneration in the superficial layer at 12 weeks. This study has demonstrated that cryopreserved meniscal allograft was capable of regeneration. The osteophyte formation of the medial femoral condyle and the tibial plateau appears to be produced by the abnormally unstable transplanted meniscus resulting from the insufficient anchorage of anterior and/or posterior horns.     

Radiologic approach to adrenal lesions.

A large number of radiologic studies are currently (or will soon be) available for the evaluation of adrenal lesions. In any given set of clinical circumstances only selected studies will be necessary, and it is important that full clinical and laboratory evaluation be performed before proceeding to radiology, so that only the needed studies are performed. This approach will provide the highest degree of accuracy with the least risk and cost for the patient.     

Implantation of perichondrium-derived chondrocytes in physeal defects of rabbit tibiae

Background Various cells and scaffolds have been used experimentally as interposition materials after physeal bar resection to treat partial physeal growth arrest. However, results of these cell therapies are unpredictable.

Methods We investigated the chondrogenic differentiation of rabbit perichondrial cells in vitro. We also investigated radiographic and histological changes after implantation of the perichondrium-derived chondrocytes, embedded in fibrin beads, into defects created in the medial aspect of the proximal tibial physis of 26 8-week-old New Zealand White rabbits. Physeal defects of the contralateral tibiae were left intact without any treatment, or were treated with fibrin beads not containing cells.

Results The perichondrial cells cultured in the alginate- fibrin beads were positive in immunohistochemical staining for S-100 protein and the extracellular area was stained with Safranin-O. RNase protection assay showed that the expression of type II collagen and aggrecan continued In the cell and bead-treated tibiae, varus deformity was reduced significantly and tibial length was maintained longer than that of the contralateral tibia. Histologically, cartilage clusters of varying size with intervening micro-bony trabeculae were found in the cell and bead-treated tibiae. The lateral, remaining physis in the untreated tibiae showed altered histology.

Interpretation Implantation of fibrin beads containing perichondrium-derived chondrocytes into the physeal defect helps to prevent angular deformation and shortening of long bone, but not completely. Physeal bony bar formation adversely affects the growth of the remaining physis from early stages onward.