Single Dose Steroid Injection After Loss of Signal (LOS) During Thyroid Surgery is Effective to Recover Electric Signal Avoiding Vocal Cord Palsy and the Need of Staged Thyroidectomy: Prospective Evaluation on 702 Patients.

BACKGROUND: Steroids are often used for the management of vocal cord palsy after thyroid surgery. There are no reports in the current literature of their intraoperative use, immediately after a loss of signal during neuromonitoring (LOS). We evaluate the impact of a single dose of 4 mg of dexamethasone on laryngeal nerve function, administrated at the time of a LOS during a nerve-monitored thyroidectomy. METHODS: A prospective not randomized study was performed, dividing patients in two groups, when a LOS was detected. LOS was defined as an electromyographic signal (EMG) inferior to 100 µV when stimulating the inferior laryngeal nerve, according to international guidelines. In group 1 (G1), surgeon waits for signal's recovery up to 20 min. Absence of a detectable signal after 20 min was predictive of vocal cord palsy; if it affected the first side of surgery the procedure was interrupted to avoid the risk of bilateral nerve palsy. In group 2 (G2), 4 mg of dexamethasone were injected within 10 min from a detected LOS, waiting 10 min for its effects. An EMG value > to 200 µV within 20' after steroid administration was predictive of full recovery and normal post-operatory vocal cord function. Vocal cords motility was checked at postoperative day 1 in all patients by an experienced ENT. RESULTS: Between January 2017 and December 2018, 702 patients underwent thyroid surgery under intermittent intraoperative nerve monitoring by two expert surgeons. A LOS was found in 22 patients in G1 and 16 in G2. Four patients in G1 spontaneously recovered electric signal (18.2%), while in G2 a signal was recovered in 14/16 patients (87.5%) (p < 0.001). This immediate effect was monitored by EMG, showing the increase in potentials at 10, 15 and 20 min after injection. ENT evaluation found vocal cord palsy, respectively, in 18/22 and 1/16 patients (G1 vs G2, p < 0.001). One of the patients in G2 who recovered electric signal presented transient palsy, fully recovered at 2 months, while the two patients who had a signal < 200 µV did not present postoperative cord palsy. In G1, 10/18 palsy were definitive. No permanent palsies were presents in G2. CONCLUSION: A single 4 mg iv dexamethasone injection within 10 min form a LOS during thyroid surgery exerts a therapeutic action, measurable by EMG modifications. It avoids vocal nerve palsy and the need of a staged thyroidectomy. It may also protect from permanent cord palsy, but the mechanism is unknown.

Evaluation of Liver Quality after Circulatory Death Versus Brain Death: A Comparative Preclinical Pig Model Study.

The current organ shortage in hepatic transplantation leads to increased use of marginal livers. New organ sources are needed, and deceased after circulatory death (DCD) donors present an interesting possibility. However, many unknown remains on these donors and their pathophysiology regarding ischemia reperfusion injury (IRI). Our hypothesis was that DCD combined with abdominal normothermic regional recirculation (ANOR) is not inferior to deceased after brain death (DBD) donors. We performed a mechanistic comparison between livers from DBD and DCD donors in a highly reproducible pig model, closely mimicking donor conditions encountered in the clinic. DCD donors were conditioned by ANOR. We determined that from the start of storage, pro-lesion pathways such as oxidative stress and cell death were induced in both donor types, but to a higher extent in DBD organs. Furthermore, pro-survival pathways, such as resistance to hypoxia and regeneration showed activation levels closer to healthy livers in DCD-ANOR rather than in DBD organs. These data highlight critical differences between DBD and DCD-ANOR livers, with an apparent superiority of DCD in terms of quality. This confirms our hypothesis and further confirms previously demonstrated benefits of ANOR. This encourages the expended use of DCD organs, particularly with ANOR preconditioning.

Cold-to-warm machine perfusion of the liver: a novel circuit for an uninterrupted combined perfusion protocol.

BACKGROUND: Ex-vivo perfusion of liver grafts is associated with promising results for the preservation of marginal grafts. Recent studies highlight the need for a combination of perfusion conditions, such as hypothermic followed by normothermic perfusion. While comprehensive machines dedicated to liver perfusion have been developed, these systems remain costly and poorly adaptable to perfusion condition switch, which requires a complete interruption of the perfusion process. Our team aimed at developing an adaptable and simple circuit for uninterrupted ex-vivo liver perfusion. METHODS: Together with specialized bioengineers, we developed a highly adaptable circuit that can fit on already pre-existing extracorporeal oxygenation machines routinely used in cardiovascular surgery. This circuit, owing to its reservoir, allows any type of perfusion conditions without interrupting the perfusion process. RESULTS: In a preliminary study, to assess the technical feasibility of liver perfusion using our circuit under different conditions, we performed 7 perfusions of discarded liver grafts. HOPE and DHOPE hypothermic perfusion could be performed, and a switch to normothermia was easily possible within seconds. From there, a dynamic perfusion sequence model was developed. CONCLUSION: This circuit may represent a simpler alternative or a new refinement to existing perfusion systems allowing uninterrupted combined perfusion protocols.

Defining the optimal duration for normothermic regional perfusion in the kidney donor: A porcine preclinical study.

Kidneys from donation after circulatory death (DCD) are highly sensitive to ischemia-reperfusion injury and thus require careful reconditioning, such as normothermic regional perfusion (NRP). However, the optimal NRP protocol remains to be characterized. NRP was modeled in a DCD porcine model (30 minutes of cardiac arrest) for 2, 4, or 6 hours compared to a control group (No-NRP); kidneys were machine-preserved and allotransplanted. NRP appeared to permit recovery from warm ischemia, possibly due to an increased expression of HIF1α-dependent survival pathway. At 2 hours, blood levels of ischemic injury biomarkers increased: creatinine, lactate/pyruvate ratio, LDH, AST, NGAL, KIM-1, CD40 ligand, and soluble-tissue-factor. All these markers then decreased with time; however, AST, NGAL, and KIM-1 increased again at 6 hours. Hemoglobin and platelets decreased at 6 hours, after which the procedure became difficult to maintain. Regarding inflammation, active tissue-factor, cleaved PAR-2 and MCP-1 increased by 4-6 hours, but not TNF-α and iNOS. Compared to No-NRP, NRP kidneys showed lower resistance during hypothermic machine perfusion (HMP), likely associated with pe-NRP eNOS activation. Kidneys transplanted after 4 and 6 hours of NRP showed better function and outcome, compared to No-NRP. In conclusion, our results confirm the mechanistic benefits of NRP and highlight 4 hours as its optimal duration, after which injury markers appear.

Rapid or Slow Time to Brain Death? Impact on Kidney Graft Injuries in an Allotransplantation Porcine Model.

The use of donors deceased after brain death (DBD) with extended criteria in response to the shortage of grafts leads to the removal of more fragile kidneys. These grafts are at greater risk of not being grafted or delayed function. A better knowledge of the pathophysiology of DBDs would improve this situation. There is a difference between the results from animal models of DBD and the clinical data potentially explained by the kinetics of brain death induction. We compared the effect of the induction rate of brain death on the recovery of post-transplant renal function in a pig model of DBD followed by allografts in nephrectomized pigs. Resumption of early function post-transplant was better in the rapidly generated brain death group (RgBD) and graft fibrosis at three months less important. Two groups had identical oxidative stress intensity but a greater response to this oxidative stress by SIRT1, PGC1-α and NRF2 in the RgBD group. Modulation of mechanistic target of rapamycin (mTOR) stimulation by NRF2 would also regulate the survival/apoptosis balance of renal cells. For the first time we have shown that an allostatic response to oxidative stress can explain the impact of the rapidity of brain death induction on the quality of kidney transplants.

Individual and Combined Impact of Oxygen and Oxygen Transporter Supplementation during Kidney Machine Preservation in a Porcine Preclinical Kidney Transplantation Model.

Marginal kidney graft preservation in machine perfusion (MP) is well-established. However, this method requires improvement in order to mitigate oxidative stress during ischemia-reperfusion, by using oxygenation or an O2 carrier with anti-oxidant capacities (hemoglobin of the marine worm; M101). In our preclinical porcine (pig related) model, kidneys were submitted to 1h-warm ischemia, followed by 23 h hypothermic preservation in Waves® MP before auto-transplantation. Four groups were studied: W (MP without 100%-O2), W-O2 (MP with 100%-O2; also called hyperoxia), W-M101 (MP without 100%-O2 + M101 2 g/L), W-O2 + M101 (MP with 100%-O2 + M101 2 g/L) (n = 6/group). Results: Kidneys preserved in the W-M101 group showed lower resistance, compared to our W group. During the first week post-transplantation, W-O2 and W-M101 groups showed a lower blood creatinine and better glomerular filtration rate. KIM-1 and IL-18 blood levels were lower in the W-M101 group, while blood levels of AST and NGAL were lower in groups with 100% O2. Three months after transplantation, fractional excretion of sodium and the proteinuria/creatinuria ratio remained higher in the W group, creatininemia was lower in the W-M101 group, and kidney fibrosis was lower in M101 groups. We concluded that supplementation with M101 associated with or without 100% O2 improved the Waves® MP effect upon kidney recovery and late graft outcome.

Vectisol Formulation Enhances Solubility of Resveratrol and Brings Its Benefits to Kidney Transplantation in a Preclinical Porcine Model.

Current organ shortages have led centers to extend the acceptance criteria for organs, increasing the risk for adverse outcomes. Current preservation protocols have not been adapted so as to efficiently protect these organs. Herein, we target oxidative stress, the key mechanism of ischemia reperfusion injury. Vectisol® is a novel antioxidant strategy based on the encapsulation of resveratrol into a cyclodextrin, increasing its bioavailability. We tested this compound as an additive to the most popular static preservation solutions and machine perfusion (LifePort) in a preclinical pig model of kidney autotransplantation. In regard to static preservation, supplementation improved glomerular filtration and proximal tubular function early recovery. Extended follow-up confirmed the higher level of protection, slowing chronic loss of function (creatininemia and proteinuria) and the onset of histological lesions. Regarding machine perfusion, the use of Vectisol® decreased oxidative stress and apoptosis at the onset of reperfusion (30 min post declamping). Improved quality was confirmed with decreased early levels of circulating SOD (Superoxide Dismutase) and ASAT (asparagine amino transferase). Supplementation slowed the onset of chronic loss of function, as well as interstitial fibrosis and tubular atrophy. The simple addition of Vectisol® to the preservation solution significantly improved the performance of organ preservation, with long-term effects on the outcome. This strategy is thus a key player for future multi-drug therapy aimed at ischemia reperfusion in transplantation.

Inhibition of complement improves graft outcome in a pig model of kidney autotransplantation.

BACKGROUND: Ischemia reperfusion injury (IRI) induced immune response is a critical issue in transplantation. Complement and contact system activation are among its key mechanisms. STUDY DESIGN: We investigated the benefits of pre-reperfusion treatment with recombinant human C1INH (rhC1INH), inhibitor of both complement and contact activation, in a pig model of kidney autotransplantation, subjecting the organ to 60 min warm ischemia prior to 24 h static preservation to maximize damage. RESULTS: Serum creatinine measurement showed that treated animals recovered glomerular function quicker than the Vehicle group. However, no difference was observed in tubular function recovery, and elevated level of urinary NGal (Neutrophil gelatinase-associated lipocalin) and plasma AST (Aspartate Aminotransferase) were detected, indicating that treatment did not influence IRI-mediated tubular cell necrosis. Regarding chronic graft outcome, rhC1INH significantly prevented fibrosis development and improved function. Immunohistochemistry and western blot showed decreased invasion by macrophages and T lymphocytes, and reduction of epithelial to mesenchymal transition. We determined the effect of treatment on complement activation with immunofluorescence analyses at 30 min post reperfusion, showing an inhibition of C4d deposition and MBL staining in treated animals. CONCLUSIONS: In this model, the inhibition of complement activation by rhC1INH at reperfusion, while not completely counteracting IRI, limited immune system activation, significantly improving graft outcome on the short and long term.

SimLife®: A New Dynamic Model for Head and Neck Surgical Oncology Simulation.

The SimLife® model consists in a human cadaver dynamized by pulsatile vascularization. The objective was to evaluate the face, contents, and constructs validity of the SimLife® model in head and neck surgical oncology simulation. Head and neck surgical oncology simulation sessions on SimLife® models were organized with lateral neck dissection and total laryngectomy. Face and contents validity were addressed by questionnaires. Constructs validity was assessed by objective structured assessment of technical skills (OSATS) score. High realism was demonstrated for consistency of tissues (7.1 ± 1.4), color of arteries and veins (7.3 ± 1.9, 8.5 ± 1.1, respectively), and vein consistency (8.5 ± 1.2). The mean OSATS score was 19.7 ± 5.4 for residents and 32.7 ± 1.9 for senior surgeon (P = .0022). SimLife® is a hyperrealistic model for head and neck surgical oncology simulation and it might become a core component of the surgical resident curriculum.

Preventing acute kidney injury during transplantation: the application of novel oxygen carriers.

INTRODUCTION: Delayed graft function (DGF) has a significant impact on kidney transplantation outcome. One of the underlying pivotal mechanisms is organ preservation and associated hypothermia and biochemical alteration. AREAS COVERED: This paper focuses on organ preservation and its clinical consequences and describes 1. A comprehensive presentation of the pathophysiological mechanism involved in delayed graft function development; 2. The impact on endothelial cells and microvasculature integrity and the consequences on transplanted organ outcome; 3. The reassessment of dynamic organ preservation motivated by the growing use of extended criteria donors and the interest in the potential of normothermia; 4. The role of oxygenation during dynamic preservation; and 5. Novel oxygen carriers and their proof of concept in transplantation, among which M101 (HEMO2life®) is currently the most extensively investigated. EXPERT OPINION: Metabolic disturbances and imbalance of oxygen supply during preservation highlight the importance of providing oxygen. Normothermia, permitted by recent advances in machine perfusion technology, appears to be the leading edge of preservation technology. Several oxygen transporters are compatible with normothermia; however, only M101 also demonstrates compatibility with standard hypothermic preservation.

Predictive factors of endocrine and exocrine insufficiency after resection of a benign tumour of the pancreas.

BACKGROUND: The aim of the present study is to evaluate the risk factors of endocrine and exocrine insufficiency occurring few years after pancreatic resections in a consecutive series of patients who underwent pancreatoduodenectomy (PD), left pancreatectomy (LP) or enucleation for benign neoplasms at a referral centre. METHODS: Pancreatic exocrine insufficiency (PEI) was defined by the onset of steatorrhea associated with weight loss, and endocrine insufficiency was determinate by fasting plasma glucose. Association between pancreatic insufficiency and clinical, pathological, and perioperative features was studied using univariate and multivariate Cox regression analysis. RESULTS: A prospective cohort of 92 patients underwent PD (48%), LP (44%) or enucleation (8%) for benign tumours, from 2005 to 2016 in the University Hospital in Poitiers (France). The median follow-up was 68.6±42.4months. During the following, 54 patients developed exocrine insufficiency whereas 32 patients presented endocrine insufficiency. In the Cox model, a BMI>28kg/m2, being a man and presenting a metabolic syndrome were significantly associated with a higher risk to develop postoperative diabetes. The risks factors for the occurrence of PEI were preoperative chronic pancreatitis, a BMI<18.5kg/m2, tumours located in the pancreatic head, biological markers of chronic obstruction and fibrotic pancreas. Undergoing LP or enucleation were protective factors of PEI. Histological categories such as neuroendocrine tumours and cystadenomas were also associated with a decreased incidence of PEI. CONCLUSION: Men with metabolic syndrome and obesity should be closely followed-up for diabetes, and patients with obstructive tumours, pancreatic fibrosis or chronic pancreatitis require a vigilant follow up on their pancreatic exocrine function.

Duct-To-Duct Biliary Anastomosis with Removable Internal Biliary Stent During Major Hepatectomy Extended to the Biliary Confluence.

BACKGROUND: Roux-en-Y hepaticojejunostomy (HJ) currently represents the gold standard after resection of the biliary confluence. This non-physiological reconstruction poses several problems such as repeated cholangitis or stricture without conventional endoscopic access. Our aim was to describe and to report both feasibility and results of duct-to-duct anastomosis with removable internal biliary drain (RIBS) as an alternative technique to the HJ after resection of the biliary confluence in patients undergoing major liver resection. METHODS: Between January 2014 and January 2018, all patients who underwent a major hepatectomy associated with resection of the biliary confluence and reconstruction by duct-to-duct biliary anastomosis with RIBS were retrospectively included. Patient demographics, tumor characteristics, pre- and postoperative outcomes, early and late biliary complications, endoscopic complications, and clinical follow-up were collected. RESULTS: Twelve patients were included. The operative time was 326 ± 45 min (range 240-380 min). There was no postoperative mortality. Only one patient experienced biliary anastomotic leakage treated exclusively by radiological and endoscopic drainage. Four patients had an asymptomatic stricture of the biliary anastomosis detected by endoscopic retrograde cholangiopancreatography (ERCP) during the extraction of the RIBS requiring iterative dilatation and replacement of the RIBS. Among 21 performed ERCP, no complications such as failure of RIBS extraction, duodenal perforation, bleeding after sphincterotomy, cholangitis, or pancreatitis were observed. After a mean and a median follow-up of respectively 15.0 ± 14.9 and 8.7 months (range 2.0-46.1 months), no cholangitis occurred. CONCLUSION: Duct-to-duct biliary anastomosis with RIBS insertion after resection of the biliary confluence represents a feasible and safe alternative to the HJ.