Orthoplastic limb reconstruction using free fibula flap after trauma: Outcomes from a retrospective European multicenter study.

BACKGROUND: Free vascularized fibula flap represents the gold standard vascularized bone graft for the management of segmental long bone defects after traumatic injury. The current study represents the largest retrospective multicenter data collection on the use of free fibula flap (FFF) for extremities' orthoplastic reconstruction after trauma aiming to highlight current surgical practice and to set the basis for updating current surgical indications. METHODS: The study is designed as a retrospective analysis of prospectively collected data between 2009 and 2021 from six European University hospitals. Patients who underwent fibula flap reconstruction after acute traumatic injury (AF) or as a late reconstruction (LF) after post-traumatic non-union of upper or lower limb were included. Only extra-articular, diaphyseal fracture were included in the study. Surgical data were collected. Time to bone healing and complications were reported as clinical outcomes. RESULTS: Sixty-two patients were included in the study (27 in the AF group and 35 in the LF group). The average patients' age at the time of the traumatic event was 45.3 ± 2.9 years in the AF group and 41.1 ± 2.1 years in the LF group. Mean bone defect size was 7.7 ± 0.6 cm for upper limb and 11.2 ± 1.1 cm (p = .32) for lower limb. Bone healing was uneventful in 69% of treated patients, reaching 92% after complementary procedures. Bone healing time was 7.6 ± 1.2 months in the acute group and 9.6 ± 1.5 months in the late group. An overall complication rate of 30.6% was observed, with a higher percentage of late bone complications in the LF group (34%), mostly non-union cases. CONCLUSIONS: FFF reconstruction represents a reliable and definitive solution for long bone defects with bone healing reached in 92% cases with a 8.4 months of average bone healing time.

Experimental swine models for perforator flap dissection in reconstructive microsurgery.

BACKGROUND: Perforator flaps account for a fraction of reconstructive procedures despite their growing popularity. Specific microsurgical skills are required for successful harvesting of perforator flaps, which are difficult to attain through direct operating room training. Cadaver and small animal dissection cannot simulate human perforator dissection, lacking either bleeding and vessel feedback or providing too small calibers. Thus, we have developed and refined over the last ten years five perforator flaps models in living pig, described their harvesting technique and provided evidence for their effectiveness as perforator flap training models. METHOD: CT angiography data from ten living pigs was used for detailed examination of the integument's vascular anatomy. Microsurgical techniques were used to standardize and harvest the perforator flaps in acute models. The same operator-assistant team, with no prior perforator flap harvesting experience, raised all flaps in a sequential manner, one animal per day, during a 7 weeks timespan. Porcine flaps were compared to human counterparts in terms of vessel caliber, dissection times. Immediate flap survival was measured as duration of perforator pulsation after completion of flap harvesting, measured every 10 minutes for up to two hours. RESULTS: Five perforator flaps were standardized, based on the deep cranial epigastric, thoracodorsal, lateral intercostal, cranial gluteal and dorsal cervical arteries and the operative technique was described in detail. Mean pig perforator size was 1.24±0.36 mm and mean pedicle diameter was 2.78±0.8 mm, which matched closely the human calibers for each flap. Total harvesting time increased 22.4% between the first two experiments due to a more cautious approach following the lack of perforator pulsation in all flaps in the first experimental animal. A total decrease of 44.4% harvesting time between second and last experiment was observed, as expected with all repetitive surgical procedures. Post-operative perforator pulsation time revealed a steep learning curve, with no or short-term pulsatile perforators in the first five pigs, followed by a 275% increase in total perforator pulsation time between 5th and 6th experimental animal. Based on these findings we provide a description of the most common mistakes, their consequences and gestures which can be trained using the pig perforator flaps, in order to overcome these mistakes. CONCLUSION: These five pig perforator flap models provide a fast and efficient learning tool to develop perforator flap harvesting skills safely. Surgical training using these five experimental models offers a similar hands-on perforator flap dissection experience as with human tissue, based on the similar sized calibers of both perforators and pedicles with their human counterparts.

Role of the Cadaver Lab in Lymphatic Microsurgery Education: Validation of a New Training Model.

BACKGROUND: Microsurgical transplantation of vascularized lymph nodes (VLNT) or lymphatic vessels (VLVT) alongside derivative lymphaticovenous procedures are promising approaches for treatment of lymphedema. However, clinically relevant training models for mastering these techniques are still lacking. Here we describe a new training model in human cadaver and validate its use as training tool for microsurgical lymphatic reconstruction. METHODS: 10 surgeons with previous exposure to microsurgery were trained in a controlled environment. Lymphatic vessel mapping and dissection in 4 relevant body regions, harvesting of five different VLNTs and one VLVT were performed in 5 fresh-frozen cadavers. The number of lymphatic vessels and lymph nodes for each VLNT were recorded. Finally, the efficacy of this model as training tool was validated using the Dundee Ready Education Environment Measure (DREEM). RESULTS: The average cumulative DREEM score over each category was 30,75 (max = 40) while individual scoring for each relevant category revealed highly positive ratings from the perspective of teaching (39,3), training 40,5 (max = 48) and self perception of the training 30,5 (max = 32) from all participants. The groin revealed the highest number of lymphatic vessels (3.2 ± 0.29) as all other regions on the upper extremity, while the gastroepiploic VLNT had the highest number of lymph nodes (4.2 ± 0.37). CONCLUSIONS: This human cadaver model represents a new, reproducible "all-in-one" tool for effective training in lymphatic microsurgery. Its unique diligence in accurately reproducing human lymphatic anatomy, should make this model worth considering for each microsurgeon willing to approach lymphatic reconstruction.

Complications and Solutions in Propeller Flap Surgery.

Propeller perforator flaps (PPFs) have long been proven as valid reconstructive tools for a wide range of soft tissue defects in different body regions. During the last decade, despite their numerous advantages, many authors have thoroughly analyzed outcomes of these flaps, sometimes discouraging their use mainly because of a high failure rate. Accurate patient selection, adequate preoperative planning, and an appropriate dissection technique seem to potentially improve outcomes. Our study provides a review of the relevant literature related to PPF complications and of our experience, describing reasons for failure, measures for preventing them, and approaches for a prompt evaluation and management of complications.

Role of Reconstructive Microsurgery in Tubal Infertility in Young Women.

AIM: Here, we retrospectively analyzed the success rate of reconstructive microsurgery for tubal infertility (RMTI) as a "first-line" approach to achieving tubal reversal and pregnancy after tubal infertility. PATIENTS AND METHODS: During 9 consecutive years (2005-2014), 96 patients diagnosed with obstructive tubal infertility underwent RMTI (tubal reversal, salpingostomy, and/or tubal implantation) in our centre. The outcomes are presented in terms of tubal reversal rate and pregnancy and correlated with age, level of tubal obstruction, and duration of tubal infertility. RESULTS: The overall tubal reversal rate was 87.56% (84 patients). The 48-month cumulative pregnancy rate was 78.04% (64 patients), of which seven ectopic pregnancies occurred (8.53%). The reversibility rate for women under 35 yo was 90.47%, with a birth rate of 73.01%. The reconstruction at the infundibular segments favored higher ectopic pregnancy rates (four ectopic pregnancies for anastomosis at infundibular level-57.14%, two for ampullary level-28.57%, and one for replantation technique-14.28%), with a significant value for p < 0.05. CONCLUSIONS: In the context of IVF "industrialization", reconstructive microsurgery for tubal infertility has become increasingly less favored. However, under available expertise and proper indication, RMTI can be successfully used to restore a woman's ability to conceive naturally with a high postoperative pregnancy rate overall, especially in women under 35 yo.

The free vastus lateralis muscle flap. A smart less used flap for soft tissue reconstruction of the weight-bearing foot.

BACKGROUND: The lateral circumflex femoral artery one of the most favoured donor-site for a wide array of free flaps including either cutaneous, fascial and muscle components or a combination thereof. Here, we provide evidence on the safe use of the free vastus lateralis muscle flap and its feasibility for optimal soft tissue coverage of the weight-bearing foot. METHODS: Eighteen consecutive patients with soft tissue defects of the heel (n = 3, 16.6%) and plantar aspect of the mid- and forefoot (n = 15, 83.3%) of either post traumatic (n = 10), diabetic (n = 6) or ischemic (n = 2) etiology, received nineteen free vastus lateralis muscle free flaps covered with split-thickness skin grafts. The postoperative results in terms of wound healing, weight-bearing function, patient satisfaction were evaluated. In patients with chronic conditions (n = 8) the AOFAS (American Orthopaedic Foot and Ankle Society) scoring system was used preoperatively and 6 months postoperatively for evaluation of reconstruction outcomes. RESULTS: All flaps survived. Their complete anatomical integration allowed regaining normal walking in all patients. In five patients, partial loss of the skin graft which either healed spontaneously or necessitated a redo skin grafting was noted. One patient developed a late flap-skin interface ulcer, which was solved by primary excision and direct closure. Compared with the preoperative values, the mean AOFAS score in the evaluated patients (n = 8) improved significantly (34.13 vs. 77.63, p < 0.001). CONCLUSION: The skin-grafted free vastus lateralis muscle flap can safely be used as a "smart" tool for coverage of weight-bearing foot providing optimal cushioning and functional results without fearing donor-side morbidity.

A sequence of flaps and dissection exercises in the living model to improve the learning curve for perforator flap surgery.

INTRODUCTION: The training to learn how to perform perforator flaps requires practice on a living model to optimize dissection and to evaluate outcome. The purpose of this study was to describe a training model that optimizes the use of animals in order to perform the maximum number of exercises per animal. MATERIAL AND METHODS: The sequence has been planned and practiced by the first and last author, recorded perfected and implemented in a two-day surgical course. The sequence was then evaluated by the trainers and the trainees by means of a questionnaire. RESULTS: All students were able to complete the sequence of exercises before the end of the second day except two (8/10) who could not complete one exercise each. The students considered the Deep Superior Epigastric Artery Perforator flap the most difficult to perform, being the most technically demanding. The sequence of exercises was judged either easily reproducible or reproducible by all the students. Two students suggested to postpone the DSEAP flap to the second day, after some training, to optimize the experience with the most challenging and rewarding flap. CONCLUSIONS: The training sequence proposed offers a wide range of exercises and allows four trainees, divided in two teams, to work and learn on the same animal. They can perform a wide range of flaps and also harvest the internal mammary vessels. The living model allows for evaluation of the quality of the surgical performance, judged by the difficulties and complications encountered during dissection, and finally through the feedback of flap perfusion.

Chronic Hindlimb Ischemia Assessment; Quantitative Evaluation Using Laser Doppler in a Rodent Model of Surgically Induced Peripheral Arterial Occlusion.

Therapeutic neoangiogenesis (TNA) holds promise as a treatment for peripheral arterial disease. Nevertheless, proper tools for in vivo pre-clinical investigation of different TNA approaches and their effects are still lacking. Here we describe a chronic ischemic hindlimb model in rats using laser Doppler quantitative evaluation of tissue perfusion. Male Wistar rats (n = 20), aged between 6-8 months, with an average weight of 287 ± 26.74 g, were used. Animals were divided into two experimental groups: group A (n = 17; hindlimb chronic ischemia model) and group B (n = 3; control). Hindlimb ischemia was induced by concomitant ligation of the right femoral and popliteal artery. Evaluation of tissue perfusion was quantified in perfusion units (PU) on a scale from 0 to 500 (500 PU = maximal detectable perfusion) by laser Doppler analysis at day 0, day 15 and day 30 after induction of ischemia. Induction of chronic ischemia in the rat hindlimb by concomitant ligation of the femoral and popliteal artery can be readily obtained but requires basic microsurgical skills. Laser Doppler analysis has shown unaltered ischemia levels throughout the study (129,17 PU ± 3.13 day 0 vs. 130,33 PU day 30 ± 3,27, p = not significant (n.s.)). We demonstrate a simple and reproducible model of chronic hindlimb ischemia in rats, with stable tissue perfusion levels that are accurately quantified using laser Doppler technology. Hence, this model can represent a valid tool for further studies involving therapeutic neoangiogenesis.

Intestinal Preservation Injury: A Comparison Between Rat, Porcine and Human Intestines.

Advanced preservation injury (PI) after intestinal transplantation has deleterious short- and long-term effects and constitutes a major research topic. Logistics and costs favor rodent studies, whereas clinical translation mandates studies in larger animals or using human material. Despite diverging reports, no direct comparison between the development of intestinal PI in rats, pigs, and humans is available. We compared the development of PI in rat, porcine, and human intestines. Intestinal procurement and cold storage (CS) using histidine-tryptophan-ketoglutarate solution was performed in rats, pigs, and humans. Tissue samples were obtained after 8, 14, and 24 h of CS), and PI was assessed morphologically and at the molecular level (cleaved caspase-3, zonula occludens, claudin-3 and 4, tricellulin, occludin, cytokeratin-8) using immunohistochemistry and Western blot. Intestinal PI developed slower in pigs compared to rats and humans. Tissue injury and apoptosis were significantly higher in rats. Tight junction proteins showed quantitative and qualitative changes differing between species. Significant interspecies differences exist between rats, pigs, and humans regarding intestinal PI progression at tissue and molecular levels. These differences should be taken into account both with regards to study design and the interpretation of findings when relating them to the clinical setting.

Predictors of Clinical Outcome after Reconstruction of Complex Soft Tissue Defects Involving the Achilles Tendon with the Composite Anterolateral Thigh Flap with Vascularized Fascia Lata.

BACKGROUND: The composite anterolateral thigh flap with vascularized fascia lata (ALT-FL flap) for covering complex soft tissue defects involving the Achilles tendon has shown promising results. The age and body mass index (BMI) are important predictors of clinical outcome after surgical treatment of Achilles tendon ruptures. In this study, we investigate whether these also influence the outcome of patients after Achilles tendon reconstruction using the ALT-FL flap. METHODS: Twenty patients (mean age: 55.9 ± 8.7 years) with complex tissue defects involving the Achilles tendon underwent reconstruction with the ALT-FL flap. Both the Achilles tendon Total Rupture Score (ATRS) and the American Orthopaedic Foot and Ankle Society (AOFAS) score were assessed preoperatively and 12 months postoperatively. In addition, postoperative magnetic resonance imaging (MRI) studies and measurements of the ankle range of motion were performed and results compared with existing literature. RESULTS: All flaps survived and MRI studies confirmed complete anatomical integration of the fascia lata as "neotendon" at the recipient site. In our patient cohort, the age did not correlate with the outcome measurements, whereas the BMI showed significant negative correlation with the postoperative ATRS (p < 0.001) and AOFAS scores (p < 0.05). The ATRS and AOFAS scores of all patients improved significantly (p < 0.001). However, obese patients with a BMI of more than 30 kg/m2 achieved significant lower ATRS (p < 0.001) and AOFAS scores (p < 0.01), as well as patients with peripheral artery disease (PAD) (p < 0.05). The mean ankle range of motion after ALT-FL flap reconstruction remained statistical insignificant compared with previous avascular or vascularized tendon repairs of the Achilles tendon. CONCLUSION: The ALT-FL flap enables reconstruction of complex tissue defects involving the Achilles tendon with good functional results. However, the presence of an increased BMI or PAD, but not necessarily the age, proves to be a predictor of poor clinical outcome and therefore should be subject to scrutiny during patient selection.

The free medial sural artery perforator flap: Versatile option for soft tissue reconstruction in small-to-moderate size defects of the foot and ankle.

BACKGROUND: The medial sural artery perforator (MSAP) flap shows advantages for reconstruction in the foot and ankle, where bulk is a liability. We evaluated the versatility of this flap and provide further evidence on its use for covering small-to-moderate size defects by comparing the outcome depending on the region of reconstruction. METHODS: Twenty-two patients with variable defects of 4 × 4 to 18 × 7 cm underwent MSAP flap reconstruction. Final outcomes of all patients were evaluated 12-months postoperatively using the AOFAS ankle-hindfoot, midfoot and hallux scale for clinical-functional evaluation, and the SF-36 health survey for quality-of-life measurement. The scores were compared in three groups according to the anatomic region of MSAP flap reconstruction. RESULTS: The flap size ranged between 6 × 4 and 21 × 9 cm. One venous congestion was salvaged by venous thrombectomy and reanastomosis, and one marginal flap necrosis healed by secondary intention. All flaps survived, and all patients returned to ambulation. Patients with reconstruction of the ankle-hindfoot or hallux showed significantly lower AOFAS ankle-hindfoot (P = 0.021) or hallux scores (P = 0.034), whereas reconstruction of the midfoot led to equal AOFAS midfoot scores (P = 0.265) as compared with patients without reconstruction in the respective region. Comparison of SF-36 physical (P = 0.936) and mental (P = 0.855) scores of all three regions remained insignificant. CONCLUSION: The MSAP flap provides thin soft tissue coverage, enabling good functional recovery after defect reconstruction all around the foot and ankle, with evident advantages in the midfoot. However, the functional outcomes after reconstruction of the ankle-hindfoot or hallux region depend on the preexistent functional impairment.

Surgical treatment in a case of giant macrodystrophia lipomatosa of the forefoot.

Macrodystrophia lipomatosa is a rare, congenital, non-hereditary disease, characterized by local gigantism of the fingers or toes. We report the case of a 37-month-old boy, with no prior past medical history, who presented with a gigantic dystrophy of the left forefoot. The location of the deformity was involving the plantar and dorsal aspect of the foot, and digits 1 to 4. After clinical examination, imaging study assessment, and differential diagnosis considerations, it was established that macrodystrophia lipomatosa was the cause of the deformity. A reconstructive surgical intervention was planned. The hypertrophied tissues were excised, resulting in a reduction in the forefoot's volume. The patient had a favorable postoperative course and ambulation was allowed with a custom-made shoe. The case represents a rare pathological entity with complex diagnostic and therapeutic considerations. As far as treatment options, the surgeon must decide between a reconstructive surgical intervention and amputation.

A sequential assessment of the preservation injury in porcine intestines.

BACKGROUND: Clinical and experimental evidence strongly suggest that ischemia-reperfusion injury after intestinal transplantation has deleterious short- and long-term effects and finding means to reduce ischemia-reperfusion injury is a major research area. The anatomical and physiological similarities between the human and porcine digestive tract favor its use as a preclinical model for translational research. Intriguingly, no systematic appraisal of the development of the intestinal preservation injury in pigs is available. MATERIALS AND METHODS: Intestinal procurement was performed in nine pigs using histidine-tryptophan-ketoglutarate solution as preservation fluid. Ileal biopsies were obtained after 8, 14, and 24 h of static cold storage (SCS), and the preservation injury was assessed morphologically (Chiu score) as well as on the molecular level. Tight junction (zonula occludens, claudin-3 and 4, tricellulin, and occludin) and adherens junctions (E-cadherin) proteins were studied using immunofluorescence and Western blot. RESULTS: Eight hours of SCS induced minimal mucosal changes (Chiu grade 1) that advanced to significant subepithelial edema (Chiu grade 3) after 24 h; progressive Goblet cell depletion was also noted. Apoptosis (studied by cleaved caspase-3 staining significantly increased after 24 h of SCS. Significant molecular changes with decreasing expression of zonula occludens, tricellulin, and occludin were evident already after 8 h of SCS and continuously worsened. Claudin-3 and Claudin-4 and E-cadherin expression remained relatively unaltered during SCS. CONCLUSIONS: Important molecular alterations precede histologic changes during SCS of the porcine intestine and may be used as more sensitive injury markers than histologic changes in intestinal ischemia and transplantation.

Mastering Lymphatic Microsurgery: A New Training Model in Living Tissue.

BACKGROUND: Advanced microsurgical techniques have emerged as a promising approach for the treatment of lymphedema, but achieving international standards is limited by a scarcity of adequate training models. The purpose of this report is to describe our in vivo porcine training model for microsurgery. STUDY DESIGN: Five female common-breed pigs (Sus scrofa domesticus) weighing 20 to 28 kg were placed under general anesthesia, and blue patent violet dye was injected to highlight lymphatic structures and prepare the pigs for anatomical exploration and microsurgery. The number and type of patent anastomoses achieved and lymph node flaps created and any anatomical differences between porcine and human vessels were noted, in light of evaluating the use of pigs as a training model for microsurgery in living tissue. RESULTS: Multiple lymphatic-venous anastomoses were created at the site of a single incision made at the subinguinal region, running medial and parallel to the saphenous vessels. Ten multiple lymphatic-venous anastomoses were created in total, and all were demonstrated to be patent. Four lymph node flaps were prepared for lymph node transfer. The superficial lymphatic collector system in the caudal limb of the pig was identified and described with particular reference to the superficial, medial (dominant), and lateral branches along the saphenous vein and its accessory. CONCLUSIONS: The authors present a safe and adaptable in vivo experimental microsurgical porcine model that provides the opportunity to practice several advanced lymphatic microsurgical techniques in the same animal. The ideal lymph node transfer training model can be developed from this anatomical detail, giving the opportunity to use it for artery-to-artery anastomoses, vein-to-vein anastomoses, and lymphatic-to-lymphatic anastomoses.

Generation of suppressive blood cells for control of allograft rejection.

Our previous studies in rats showed that incubation of monocytic dendritic cells (DCs) with the chemotherapeutic drug mitomycin C (MMC) renders the cells immunosuppressive. Donor-derived MMC-DCs injected into the recipient prior to transplantation prolonged heart allograft survival. Although the generation of DCs is labour-intensive and time-consuming, peripheral blood mononuclear cells (PBMCs) can be easily harvested. In the present study, we analyse under which conditions DCs can be replaced by PBMCs and examine their mode of action. When injected into rats, MMC-incubated donor PBMCs (MICs) strongly prolonged heart allograft survival. Removal of monocytes from PBMCs completely abrogated their suppressive effect, indicating that monocytes are the active cell population. Suppression of rejection was donor-specific. The injected MICs migrated into peripheral lymphoid organs and led to an increased number of regulatory T-cells (Tregs) expressing cluster of differentiation (CD) markers CD4 and CD25 and forkhead box protein 3 (FoxP3). Tolerance could be transferred to syngeneic recipients with blood or spleen cells. Depletion of Tregs from tolerogenic cells abrogated their suppressive effect, arguing for mediation of immunosuppression by CD4⁺CD25⁺FoxP3⁺ Tregs. Donor-derived MICs also prolonged kidney allograft survival in pigs. MICs generated from donor monocytes were applied for the first time in humans in a patient suffering from therapy-resistant rejection of a haploidentical stem cell transplant. We describe, in the present paper, a simple method for in vitro generation of suppressor blood cells for potential use in clinical organ transplantation. Although the case report does not allow us to draw any conclusion about their therapeutic effectiveness, it shows that MICs can be easily generated and applied in humans.

The rat model in microsurgery education: classical exercises and new horizons.

Microsurgery is a precise surgical skill that requires an extensive training period and the supervision of expert instructors. The classical training schemes in microsurgery have started with multiday experimental courses on the rat model. These courses have offered a low threat supervised high fidelity laboratory setting in which students can steadily and rapidly progress. This simulated environment allows students to make and recognise mistakes in microsurgery techniques and thus shifts any related risks of the early training period from the operating room to the lab. To achieve a high level of skill acquisition before beginning clinical practice, students are trained on a comprehensive set of exercises the rat model can uniquely provide, with progressive complexity as competency improves. This paper presents the utility of the classical rat model in three of the earliest microsurgery training centres and the new prospects that this versatile and expansive training model offers.

In this issue: transplant immunology and transplant biology.

Transplantation faces an unprecedented shortage of organs available for transplantation, resulting in longer waiting times and transplant candidates on the waiting list dying before getting a transplant. This dramatic situation triggered the search for new approaches and innovations to increase the donor pool, such as extending the acceptance criteria concerning donor age or organ transplantation across blood group barriers. Herein, leading experts detailed the immunological and molecular concepts behind the successful clinical translation of these strategies. Organ rejection remains a constant challenge and transplantation tolerance is still elusive as the current paradigm aims for immunosuppression rather than immune modulation. Two contributions in this issue review two different molecular paradigms in harnessing the immunologic response after transplantation. The interplay between the intestinal innate and adaptive immunity is particularly intricate and the intestine remains the organ with the highest rate of acute rejection after transplantation. Experts in the field summarized both time-honored and recent knowledge in intestinal preservation and tolerance in intestinal transplantation with potential for further basic and translational research.

Induction of therapeutic neoangiogenesis using in vitro-generated endothelial colony-forming cells: an autologous transplantation model in rat.

BACKGROUND: Accumulating evidence shows the potential of bone marrow-derived endothelial colony-forming cells (bmECFCs) as promising tools for vascular repair. However, knowledge about their in vitro expansion, characterization, and functional behavior is still controversial. We demonstrate the in vitro generation of rat bmECFCs and analyze their ability to promote tissue reperfusion in a chronic hind-limb ischemia model. METHODS: Either in vitro-generated and characterized autologous bmECFCs or placebo was injected into ischemic hind limbs of Sprague-Dawley rats. Tissue perfusion was quantified by laser Doppler, in perfusion units (PU), at days 0, 15, and 30. RESULTS: Rat bmECFCs acquire a typical phenotype (CD34(+)VEGFR2(+)CD133(+)CXCR4(+)CD45(-)), culture, and functional behavior (Dil-ac-LDL+) in vitro. Injection of autologous bmECFCs improves tissue perfusion in ischemic hind limbs (183.5 ± 3.29 PU(bmECFCs/day 30)versus 131 ± 3.9 PU(controls/day 30), P < 0.001). CONCLUSIONS: We conclude that rat bmECFCs promote ischemic tissue reperfusion and their proangiogenic properties are a potential mechanism for this effect.

Hindpaw withdrawal from a painful thermal stimulus after sciatic nerve compression and decompression in the diabetic rat.

INTRODUCTION: Although the effect of chronic compression and surgical decompression of the diabetic rat sciatic nerve has been evaluated by walking track analysis, the measurement of sensory function by response to thermal nociceptive stimulation has not been investigated. METHODS: Fifteen male Wistar rats with streptozotocin-induced diabetes underwent sciatic nerve compression through a 10-mm silicone band. Five rats had histology done 60 days after confirming chronic nerve compression. Pain threshold was measured using hindlimb withdrawal times (HLWT) from a heat stimulus. After 60 days of compression, the silicone tube was removed. Five nondiabetic, nonbanded rats were used as controls. RESULTS: Control mean HLWT was 9.7 ± 1.5 sec. In the diabetes group (60 days of compression), mean HLWT was 23.6 ± 2.4 sec. (p < 0.001). Thirty days after removal of the silicone, mean HLWT to painful stimuli was 14.9 ± 1.5 sec. (p < 0.001). CONCLUSION: Chronic compression of the diabetic rat sciatic nerve increases (worsens) the threshold to heat (pain) perception. Decompression reverses this effect (improves nociception).