In Situ Venous Bypass for Chronic Hand Ischemia: A Review of 25 Cases in 23 Patients.

BACKGROUND: Chronic ischemia of the hand in the setting of atherosclerotic disease is a challenging problem that leads to serial amputations and significant morbidity. Salvage using an in situ venous bypass has been described. In selected cases, leaving the vein in situ for bypass allows a good size match for anastomosis at the wrist or palmar arch. Due to the rarity of the condition, there is a paucity of data regarding the efficacy of this technique. METHODS: Outcomes in 23 consecutive patients that underwent a total of 25 in situ vein grafts over a 16-year period were retrospectively reviewed. RESULTS: Eighteen were men and 5 were women with a mean age of 61 years. Target vessels at the wrist or palmar arch were identified on preoperative vascular imaging. The cephalic vein (n = 19, 76%) was most commonly used followed by the basilic vein (n = 6, 24%). Overall patency rate at a mean follow-up period of 12.1 months was 92%. Success as determined by both symptomatic improvement and resolution of the ischemic changes or toleration of revision amputation was achieved in 16 (64%) cases. Postoperative complications occurred in ten cases (40 %). Progression of ischemia occurred in 7 cases (28 %) and 3 (12 %) of these cases required a hand amputation. CONCLUSIONS: In situ vein grafts in the upper extremity offer good short-term patency rates and can be used for salvage of chronic hand ischemia.

Differentiated adipose-derived stem cell cocultures for bone regeneration in polymer scaffolds in vivo.

Critical-sized bone defects can lead to significant morbidity, and interventions are limited by the availability and donor-site morbidity of bone grafts. Polymer scaffolds seeded with cells have been explored to replace bone grafts. Adipose-derived stem cells have shown great promise for vascularization and osteogenesis of these constructs, and cocultures of differentiated stem cells are being explored to augment vessel and bone formation. Adipose-derived stem cells were differentiated into endothelial cells and osteoblasts, and in vitro studies showed increased proliferation of cocultured cells compared with undifferentiated adipose-derived stem cells and monocultures of endothelial cells and osteoblasts. The cells were seeded into polylactic acid gas-plasma-treated scaffolds as cocultures and monocultures and then implanted into critical-sized rat calvarial defects. The cocultures were in a 1:1 osteoblast to endothelial cell ratio. The increase in proliferation seen by the cocultured cells in vitro did not translate to increased vascularization and osteogenesis in vivo. In vivo, there were trends of increased vascularization in the endothelial cell group and increased osteogenesis in the osteoblast and endothelial monoculture groups, but no increase was seen in the coculture group compared with the undifferentiated adipose-derived stem cells. Endothelial cells enhance vascularization and osteoblast and endothelial cell monocultures enhance bone formation in the polymer scaffold. Predifferentiation of adipose-derived stem cells is promising for improving vascularization and osteogenesis in polymer scaffolds but requires future evaluation of coculture ratios to fully characterize this response.

Urethral reconstruction using a prefabricated pedicled gracilis flap.

This case study describes a patient who experienced an iatrogenic urethral injury because of a Fournier gangrene debridement. Because of the extent of the debridement, which resected all penile and scrotal dartos tissue, no local flaps that would typically be used to reconstruct a urethral disruption were possible. The authors chose to use a prefabricated pedicled gracilis flap to restore urethral continuity.

Analysis of free flap complications and utilization of intensive care unit monitoring.

We aimed to determine the optimal time for intensive care unit (ICU) monitoring after free flap reconstruction based on the timing of surgical complications. We reviewed retrospectively 179 free flaps in 170 subjects during an 8-year period at University Hospital. Thirty-seven flaps were reoperated due to vascular (n = 16, 8.9%) and nonvascular complications (n = 21, 11.7%). Vascular complications presented earlier relative to nonvascular complications (10.8 versus 99.3 hours). The flap survival rate was 93.2% with a mean ICU length of stay of 6.2 days. The lack of standardized monitoring protocols can lead to overutilization of ICU. Sometimes, flap monitoring is not the limiting factor, as patients with other comorbidities necessitate longer ICU stays. However, our study suggests that close monitoring of flaps seems most critical during the first 24 to 48 hours, when most thrombotic complications occur and prompt identification and re-exploration is critical. Some thrombosis and most hematomas present within 72 hours, and thus close monitoring is still warranted. We suggest close monitoring of free flaps in the ICU or dedicated flap monitoring unit where nursing can check the flap on an every-1-to-2-hour basis for the first 72 hours postoperatively to assure optimal surveillance of any potential problems.

Pig heart preservation with antegrade intracellular crystalloid versus antegrade/retrograde miniplegia.

Both histidine-tryptophan-ketoglutarate (HTK) solution and Braile miniplegia are commercially available and used with high success. The objective of this work was to compare the effects of both strategies in an animal model. Twelve pigs were divided into control, HTK, or Braile groups using a model of controlled global cardiac ischemia/reperfusion under cardiopulmonary bypass with 1 hour heart ischemia followed by 2 hour reperfusion. No significant differences were found over time or between groups for heart rate, arrhythmia, number of defibrillations required, blood gases, myocardial lactate production, myocardial oxygen consumption, nor coronary flow index. The Braile strategy was associated with a lower 120 minute postreperfusion coronary vascular resistance with higher water content, leukocyte infiltration, and oxidative damage compared with controls. Drainage of HTK solution to the venous return was followed by higher potassium and lower sodium blood concentrations. One-hour heart preservation with HTK or Braile systems followed by 2 hour reperfusion both allow for acceptable preservation of the healthy pig myocardium. Maneuvers such as leukocyte filtration or hemofiltration may further improve these conditions.

The use of visible light spectroscopy to measure tissue oxygenation in free flap reconstruction.

The loss of a free flap is a feared complication for both the surgeon and the patient. Early recognition of vascular compromise has been shown to provide the best chance for flap salvage. The ideal monitoring technique for perioperative free flap ischemia would be noninvasive, continuous, and reliable. Visible light spectroscopy (VLS) was evaluated as a new method for predicting ischemia in microvascular cutaneous soft tissue free flaps. In an Institutional Review Board-approved prospective trial, 12 patients were monitored after free flap reconstructions. The tissue hemoglobin oxygen saturation (StO (2)) and total hemoglobin concentration (THB) of 12 flaps were continuously monitored using VLS for 72 hours postoperatively. Out of these 12 flaps 11 were transplanted successfully and 1 flap loss occurred. The StO (2 )was 48.99% and the THB was 46.74% for the 12 flaps. There was no significant difference in these values among the flaps. For the single flap loss, the device accurately reflected the ischemic drop in StO (2) indicating drastic tissue ischemia at 6 hours postoperatively before the disappearance of implantable Doppler signals or clinical signs of flap compromise. VLS, a continuous, noninvasive, and localized method to monitor oxygenation, appeared to predict early ischemic complications after free flap reconstruction.

Modifying hernia mesh design to improve device mechanical performance and promote tension-free repair.

PURPOSE: Approximately 348,000 ventral hernia repairs are performed annually in the United States and the incisional hernia recurrence rate is approximately 20% as a result of suture and mesh device failure. Device failure is related to changes at the suture/tissue interface that leads to acute or chronic suture pull-through and surgical failure. To better manage mechanical tension, we propose a modified mesh design with extensions and demonstrate its mechanical superiority. METHODS: Comparative uniaxial static tensile testing was conducted on polypropylene suture and a modified mesh. Subsequently, a standard of care (SOC) mesh and modified mesh were evaluated using a tensometer in an acute hernia bench-top model. RESULTS: Modified mesh breaking strength, extension knot breaking strength, extension disruption, and extension anchoring were superior to suture (p < .05). Modified mesh ultimate tensile strength of anchoring was superior to SOC mesh (p < .05). Various stitch patterns and modifications in device design significantly improved device tension-free performance far beyond clinically relevant benchmarks (p < .05). CONCLUSIONS: Testing demonstrates that the modified mesh outperforms SOC mesh and suture in all tested failure modes. SOC hernia mesh tears through tissue at stress levels below maximum physiologic stress, whereas, the modified hernia mesh is up to 200% stronger than SOC mesh at resisting suture tearing through tissue and maintains anchoring at stresses far beyond clinically relevant benchmarks. Modifying hernia mesh design significantly improves device mechanical performance and enhances tension-free repair.

Postoperative monitoring of free flap reconstruction: A comparison of external Doppler ultrasonography and the implantable Doppler probe.

HYPOTHESIS: The time to detection of vascular compromise and the postoperative time to re-exploration are shorter using the implantable Doppler (ID) probe, thereby resulting in earlier surgical re-exploration and a higher flap salvage rate. METHODS: A single-centre experience with 176 consecutive free flap reconstructions in 167 patients from 2000 to 2008 in a university-based teaching hospital by retrospective chart review is presented. RESULTS: There was a significant difference in overall flap survival (ID 98.0%, external Doppler [ED] 89.3%) and total flap loss (ID 2.0%, ED 10.7%) between the two groups (P=0.03). The difference in flap salvage rate was not significant (ID 90.9%, ED 63.6%; P=0.068). The false-positive (ID 0%, ED 3%; P=0.18) and false-negative rates (ID 0.0%, ED 4.5%; P=1.0) were not significantly different. There was also a lower median postoperative time to re-exploration for the ID group, from 48 h to one week after initial surgery (ID 74.5 h, ED 136.8 h; P=0.05). CONCLUSION: The present analysis revealed a potential benefit for the ID probe in the postoperative monitoring of free tissue transfers.

HYPOTHÈSE: Le délai entre la détection d'une atteinte vasculaire et la réexploration postopératoire est plus court à l'aide de la sonde Doppler implantable (DI), ce qui favorise une réexploration chirurgicale plus rapide et un taux plus élevé de sauvegarde des lambeaux. MÉTHODOLOGIE: Les auteurs présentent l'expérience monocentrique de 176 reconstructions consécutives par lambeaux libres chez 167 patients entre 2000 à 2008 dans un hôpital universitaire au moyen d'une analyse de leurs dossiers. RÉSULTATS: Il y avait une différence importante dans la survie globale des lambeaux (DI 98,0 %, Doppler externe [DE] 89,3 %) et perte totale des lambeaux (DI 2,0 %, DE 10,7 %) entre les deux groupes (P=0,03). La différence en matière de taux de sauvegarde des lambeaux n'était pas significative (DI 90,9 %, DE 63,6 %; P=0,068). Les taux de résultats faussement positifs (DI 0 %, DE 3 %; P=0,18) et de résultats faussement négatifs (DI 0,0 %, DE 4,5 %; P=1,0) n'étaient pas sensiblement différents. Le délai postopératoire médian avant la réexploration était également plus court dans le groupe DI, soit de 48 heures à une semaine après l'opération initiale (DI 74,5 h, DE 136,8 h; P=0,05). CONCLUSION: La présente analyse a révélé l'avantage potentiel de la sonde DI lors de la surveillance postopératoire des transferts de tissus libres.

Immunosuppression and procedure-related complications in 26 patients with type 1 diabetes mellitus receiving allogeneic islet cell transplantation.

BACKGROUND: The success of sirolimus and low-dose tacrolimus in islet cell transplantation has influenced many transplant centers to utilize this novel regimen. The long-term safety and tolerability of this steroid-free immunosuppressive protocol for allogeneic islet transplantation has yet to be determined. METHODS: We transplanted 26 adult patients with long standing type 1 diabetes mellitus between April 2000 and June 2004. Immunosuppression consisted of induction with daclizumab and maintenance therapy with tacrolimus and sirolimus. Adverse events (AEs) in patients were followed and graded using the Common Terminology Criteria for Adverse Events, version 3.0 (National Cancer Institute). RESULTS: To date, the majority of patients were able to remain on the immunosuppression combination for up to 22+/-11 months. Four patients were successfully converted to Mycophenolate Mofetil due to tacrolimus-related toxicity. Withdrawal from immunosuppression was decided in four patients due to hypereosinophilic syndrome, parvovirus infection, aspiration pneumonia, and severe depression, respectively. Six patients required filgrastim therapy for neutropenia. Transient elevation of liver enzymes was observed in most patients early after islet infusion. Increased LDL in 20 patients required medical treatment. CONCLUSION: There was a varying range of AEs, most of them mild and self-limiting; however, some required urgent medical attention. The majority of patients were able to tolerate and remain on this effective regimen. To date, no deaths, cytomegalovirus disease, graft-versus-host disease, or posttransplant lymphoproliferative disease has been observed.

Alterations of the female reproductive system in recipients of islet grafts.

BACKGROUND: Transplantation of allogeneic tissues is becoming a wider practice for the replacement of organ function lost to congenital or acquired pathologies. Chronic immunosuppression remains a necessity to prevent organ rejection, despite increased risks of infection, organ toxicity, and malignancies. Abnormalities of female gonadal function in patients of reproductive age are recognized, however, pathological alterations of the reproductive system in patients treated with new generation immunosuppressive drugs are still poorly documented. METHODS: We report herein our observations of abnormalities of the reproductive system in 13 female recipients of allogeneic islets for type 1 diabetes, under immunosuppression therapy based on daclizumab induction and tacrolimus/sirolimus maintenance. RESULTS: Menstrual cycle alterations and clinically significant ovarian cysts were frequently observed in our patients, some requiring medical or surgical intervention. All ovarian cysts appeared of benign nature. CONCLUSIONS: Our findings suggest that pre- and posttransplant evaluation of female patients should include menstrual history, baseline pelvic ultrasound, and hormonal levels to assess the presence and monitor the progression of such alterations.

Effect of adipose tissue-derived osteogenic and endothelial cells on bone allograft osteogenesis and vascularization in critical-sized calvarial defects.

The use of processed bone allograft to repair large osseous defects of the skull has been limited, given that it lacks the osteogenic cellularity and intrinsic vascular supply which are essential elements for successful graft healing and, at the same time, the areas to be targeted through tissue-engineering applications. In this study, we investigated the effect of predifferentiated rat adipose tissue-derived osteoblastic cells (OBs) and endothelial cells (ECs) on calvarial bone allograft healing and vascularization using an orthotopic critical-sized calvarial defect model. For this purpose, thirty-seven 8 mm critical calvarial defects in Lewis rats were treated with bone allografts seeded with no cells, undifferentiated adipose tissue-derived stem cells (ASC), OBs, ECs, and OBs and ECs simultaneously. After 8 weeks, the bone volume and mineral density were calculated using microcomputed tomography and the microvessel formation using immunohistochemical staining and imaging software. The amount of bone within the 8 mm defect was significantly higher for the allografts treated with ECs compared with the allografts treated with OBs (p=0.05) and simultaneously with the two cell lineages (p=0.02). There were no significant differences in bone formation between the latter two groups and the control groups (allografts treated with no cells and undifferentiated ASC). There were no significant differences in bone mineral density among the groups. The amount of microvessels was significantly higher in the group treated with ECs relative to all groups (p=< 0.05). Our results show that the implantation of ASC-derived ECs improves the vascularization of calvarial bone allografts at 8 weeks after treatment. This cell-based vascularization strategy can be used to improve the paucity of perfusion in allogenic bone implants. However, in this study, the treatment of allografts with OBs alone or in combination with ECs did not support bone formation or vascularization.

Intestinal perforation associated with rituximab therapy for post-transplant lymphoproliferative disorder after liver transplantation.

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication after organ transplantation with a cumulative incidence of 1.1% at 18 months and 4.7% at 15 years. It has been reported in patients with or without concomitant Epstein-Barr virus infection. Therapy ranges from a reduction of immunosuppression to administration of conventional cytotoxic chemotherapy. Rituximab, a recombinant chimeric anti-CD20 monoclonal antibody has been used for the treatment of PTLD with promising results and a reduction in treatment-associated mortality. However, the use of rituximab has been associated with spontaneous gastrointestinal perforation. We describe a case of recurrent intestinal perforations after a single dose of rituximab.