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INTRODUCTION: Even though incidence of recurrent laryngeal nerve palsy (RLNP) is low, it affects importantly the quality of life of patients and remains one of main medicolegal litigation problems in surgery. Intraoperative neuromonitoring (IONM) has become widely accepted tool helping in recurrent laryngeal nerve identification, however no clear association of IONM with RLNP rate has been demonstrated. The aim of our study was to assess whether training in IONM influences rates of RNLP after thyroid surgery as an independent factor. MATERIAL AND METHODS: We analysed retrospectively 1235 patients who underwent thyroidectomy at the 1st Department of General and Endocrine Surgery, Medical University of Bialystok. Possible risk factors for RLNP were evaluated: application or not of IONM, the extent of surgery or thyroid pathology in correlation with surgeons' experience in IONM (trained or untrained). RESULTS: There were 2351 nerves at risk (NAR) and 39 RNLP were diagnosed after thyroid surgery (1.66%). Surgeons trained in IONM performed 52.2% of all operations (1200 NAR) with 7 RLNP (0.58%), whereas not-trained had 32 RLNP for 1151 NAR (2.8%; p < 0.001). After 182 thyroidectomies (357 NAR) guided by IONM (14.7%) 3 RLNP were observed (0.84%) vs. 36 palsies per 1994 NAR without IONM (1.81%; p = 0.189). The highest danger of RLNP was reported after reoperations and the lowest after subtotal thyroidectomies. We found no association between thyroid pathology and RLNP rate. CONCLUSIONS: According to our study training in IONM decreases chances of RLNP especially during total or near total thyroidectomy.
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BACKGROUND: Ischemia-reperfusion injury after organ transplantation is a major cause of delayed graft function. Prevention of post-transplant ischemia acute renal failure is still elusive. METHODS: The present study was designed to examine whether propionyl-l-carnitine, an acyl derivative of carnitine involved in fatty acid oxidation pathway and adenosine 5'-triphosphate (ATP) generation of mitochondria, prevented renal function deterioration and structural injury induced by ischemia-reperfusion in an ex vivo rat model of isolated perfused kidney (IPK) preparation and in vivo in a model of syngeneic kidney transplantation. RESULTS: In the model of ischemia (20 or 40 min)/reperfusion (90 or 70 min) in IPK, untreated kidneys showed a marked reduction of glomerular filtration rate (GFR) and renal perfusate flow (RPF) as compared to baseline, when perfusion was established by restoring effective perfusion pressure to 100 mm Hg. Exposure of kidneys to propionyl-l-carnitine before establishing the ischemia insult to tissue, largely prevented renal function impairment. Pre-exposure of ischemic kidneys to propionyl-l-carnitine largely reduced the percent of lactate dehydrogenase (LDH), a cell injury marker, released into the perfusate after reperfusion as compared to untreated ischemic kidneys. Histologic findings showed very mild post-ischemic lesions in kidneys exposed to propionyl-l-carnitine as compared to untreated ischemic kidneys. Immunohistochemical detection of 4-hydroxynonenal protein adduct, a major product of lipid peroxidation, was very low in kidney infused with propionyl-l-carnitine and exposed to ischemia/reperfusion as compared to untreated ischemic kidneys. ATP levels were not affected by propionyl-l-carnitine treatment. Renal function of kidneys exposed for four hours to cold Belzer UW solution added with propionyl-l-carnitine and transplanted to binephrectomized recipients was largely preserved as compared to untreated ischemic grafts. Propionyl-l-carnitine almost completely prevented polymorphonuclear cell graft infiltration and reduced tubular injury at 16 hours post-transplant. CONCLUSIONS: These data indicate that propionyl-l-carnitine is of value in preventing decline of renal function that occurs during ischemia-reperfusion. The beneficial effect of propionyl-l-carnitine possibly relates to lowering lipid peroxidation and free radical generation that eventually results in the preservation of tubular cell structure. The efficacy of propionyl-l-carnitine to modulate ischemia-reperfusion injury in these models opens new perspectives for preventing post-transplant delayed graft function.
