Pretransplant predictors of early mortality in adult recipients of liver transplantation in the MELD-Na Era. / Predictores pretrasplante de mortalidad precoz en receptores adultos de trasplante hepático en la era MELD-Na.

AIMS: To identify pretransplant predictors of early mortality (90 days after transplantation) and evaluate their discriminating capacity in adult liver transplant recipients (LTR). DESIGN: An observational, retrospective, nested cases-controls study from a consecutive cohort of LTRs was carried out. SETTING: University hospital. PATIENTS: All consecutive LTR between January 2003 and December 2016 were eligible for inclusion. Patients with acute liver failure, previous graft dysfunction, simultaneous multiple organ transplantation, non-heart beating donors, and those needing urgent retransplantation during the study period were excluded. The analysis comprised 471 patients. MAIN VARIABLES OF INTEREST: Pretransplant characteristics were the main variables of interest. The LTR were grouped according to the dependent variable (early mortality). Multivariate logistic regression analysis was conducted to identify predictors of early mortality. The discriminating capacity of the models obtained was evaluated by comparing ROC curves (models versus MELD-Na). RESULTS: The MELD-Na score (OR = 1.069, 95% CI = 1.014-1.127), age > 60 years (OR = 2.479, 95% CI = 1.226-5.015), and LTR height < 163cm (OR = 4.092, 95% CI = 2.115-7.917) were identified as independent predictors of early mortality. The cause of transplantation (hepatocellular carcinoma or decompensated cirrhosis) was identified as a confounding factor. CONCLUSIONS: In LTR due to decompensated cirrhosis, the MELD-Na score, age > 60 years, and height < 163cm are independent predictors of early mortality. These factors provide a better classification model than the MELD-Na score for early post-transplant mortality.

CHRONIC UNPREDICTABLE MILD STRESS PROGRESSIVELY DISTURBS GLUCOSE METABOLISM AND APPETITE HORMONES IN RATS.

CONTEXT: Chronic stress is characterized by increased release of catecholamines, glucocorticoids and other neurohumoral factors, predisposing individuals to obesity, insulin resistance and vascular disease, pathologies considered priority health problems. Study of alterations induced by stress on metabolism in association with food intake modulatory hormones (insulin, leptin and ghrelin) is mandatory. OBJECTIVE: This research studied temporal course during 60 days of chronic unpredictable mild stress (CUMS) on glucose and lipids metabolism, and on the neuroendocrine system that regulates appetite-satiety balance. MATERIALS AND METHODS: Wistar rats were exposed to CUMS for 20, 40 and 60 days. Corticosterone stayed high during 60 days of CUMS; after 40 days, body weight, cholesterol and triglycerides decreased and glucose intolerance was evident at day 60; insulin and ghrelin increased at 20 and 40 days, respectively; leptin decreased after day 20. Data suggest that 60 days of CUMS progressively disturb metabolism of carbohydrates and lipids as well as food intake regulatory hormones, affecting the metabolism, and can lead to the development of chronic degenerative diseases, such as cardiovascular disease, metabolic syndrome and type 2 diabetes.

Peritonectomy procedures and HIPEC in the treatment of peritoneal carcinomatosis from ovarian cancer: Long-term outcomes and perspectives from a high-volume center.

BACKGROUND: Cytoreductive surgery with peritonectomy procedures and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) represents a radical therapeutic approach to achieve complete cytoreduction in ovarian peritoneal carcinomatosis. The aim of the present study was to analyze the outcomes obtained by the application of these procedures in a single center with extensive experience treating peritoneal carcinomatosis. PATIENTS AND METHODS: A series of 218 consecutive patients diagnosed with peritoneal carcinomatosis from primary or recurrent ovarian cancer (FIGO stage IIIC-IV) and treated with CRS + HIPEC between January 1996 and June 2012 were included in this observational study. RESULTS: Peritoneal carcinomatosis was treated primarily in 56% (124/218) of the cases and recurrently in 43% (94/218). A total of 42/218 patients (19%) presented with FIGO stage IV. Compared to recurrent cases, patients with primary ovarian carcinomatosis were older and presented higher Peritoneal Cancer Index (PCI) and percentage of FIGO stage IV; however, no significant differences in survival (5-year overall survival in patients with R0 cytoreduction, 63% and 56%, respectively) were observed. Cytoreduction score, PCI, lymphatic involvement and surgical morbidity ≥Grade III were statistically significant prognostic factors for survival in both univariate and multivariate analysis. CONCLUSIONS: CRS + HIPEC treating macroscopic and microscopic disease is currently an excellent surgical approach to achieve high rates of complete cytoreduction and improve survival in patients with peritoneal carcinomatosis from ovarian cancer. In order to minimize the high potential morbidity of these procedures, CRS + HIPEC should be performed in highly experienced centers.

Sagittal otolith morphogenesis asymmetry in marine fishes.

This study investigated and compared asymmetry in sagittal otolith shape and length between left and right inner ears in four roundfish and four flatfish species of commercial interest. For each species, the effects of ontogenetic changes (individual age and total body length), sexual dimorphism (individual sex) and the otolith's location on the right or left side of the head, on the shape and length of paired otoliths (between 143 and 702 pairs according to species) were evaluated. Ontogenetic changes in otolith shape and length were observed for all species. Sexual dimorphism, either in otolith shape and length or in their ontogenetic changes, was detected for half of the species, be they round or flat. Significant directional asymmetry in otolith shape and length was detected in one roundfish species each, but its inconsistency across species and its small average amplitude (6·17% for shape and 1·99% for length) suggested that it has barely any biological relevance. Significant directional asymmetry in otolith shape and length was found for all flatfish species except otolith length for one species. Its average amplitude varied between 2·06 and 17·50% for shape and between 0·00 and 11·83% for length and increased significantly throughout ontogeny for two species, one dextral and one sinistral. The longer (length) and rounder otolith (shape) appeared to be always on the blind side whatever the species. These results suggest differential biomineralization between the blind and ocular inner ears in flatfish species that could result from perturbations of the proximal-distal gradient of otolith precursors in the endolymph and the otolith position relative to the geometry of the saccular epithelium due to body morphology asymmetry and lateralized behaviour. The fact that asymmetry never exceeded 18% even at the individual level suggests an evolutionary canalization of otolith shape symmetry to avoid negative effects on fish hearing and balance. Technically, asymmetry should be accounted for in future studies based on otolith shape.

Negative outcomes associated with medication in patients with chronic atrial fibrillation who present at the emergency department.

WHAT IS KNOWN AND OBJECTIVE: Medication is the main treatment option for patients with chronic atrial fibrillation. However, medication can have negative effects. We aimed to detect negative outcomes associated with medication that led to patients with chronic atrial fibrillation presenting themselves to hospital emergency departments. We assessed the severity of those outcomes and comment on whether they could have been avoided. METHODS: This descriptive, cross-sectional study included all patients with chronic atrial fibrillation who attended the emergency department of our tertiary hospital. We used the Dader method to identify and evaluate the negative outcomes associated with medication through interviews with patients and scrutiny of the clinical charts. RESULTS AND DISCUSSION: Of the 198 eligible patients who presented at the emergency department, 134 (67·7%) did so because of negative outcomes associated with medication (41% related to necessity, 32·1% to effectiveness and 26·9% to safety); 67·9% of those negative outcomes could have been avoided. In terms of severity, 6·7% were mild, 31·3% moderate, 51·5% severe and 10·4% fatal. The Anatomical Therapeutic Chemical Classification anatomical group most frequently associated with negative outcomes was the cardiovascular system, followed by blood/blood-forming organs. WHAT IS NEW AND CONCLUSION: A high percentage of patients with chronic atrial fibrillation presenting at hospital emergency departments had negative outcomes associated with medication. Some led to deaths. More than half of these were severe, and most could have been avoided.

Pre-transplant thymic function is associated with the risk of cytomegalovirus disease after solid organ transplantation.

Cytomegalovirus (CMV) disease is an important complication in solid organ transplant recipients. Thymic function in adults is associated with specific T-cell immunity. Pre-transplant thymic function was analysed in 75 solid organ transplant patients by the use of nested PCR. The primary outcome was the incidence of CMV disease 12 months after transplantation. Using multivariable logistic regression, we studied whether pre-transplant thymic function is an independent risk factor for CMV disease after transplantation. Thymic function was related to the risk of CMV disease in CMV-seropositive recipients. In these recipients, pre-transplant thymic function of <9.5 (OR 11.27, 95% CI 1.11-114.43, p 0.040) and the use of thymoglobulin (OR 8.21, 95% CI 1.09-61.84, p 0.041) were independent risk factors for CMV disease at 12 months after transplantation. Patients with pre-transplant thymic function values of <9.5 had a higher subsequent incidence of CMV disease (24%) than patients with values of ≥ 9.5 (3%) (log-rank test: 5.727; p 0.017). The positive and negative predictive values of these pre-transplant thymic function cut-offs were 0.24 (95% CI 0.10-0.45) and 0.97 (95% CI 0.82-1.00), respectively. Pre-transplant thymic function in CMV-seropositive candidates could be useful in determining the risk of post-transplant CMV disease in solid organ transplant patients, selecting a group of low-risk candidates.

Morphological variability of the shape of striped red mullet Mullus surmuletus in relation to stock discrimination between the Bay of Biscay and the eastern English Channel.

Truss analysis and length measurements were made on 168 striped red mullet Mullus surmuletus. Multivariate statistical analyses with principal component analysis and partial redundancy analysis (pRDA) were used on these measurements to evaluate the influence of maturity, sex and geographical area distribution on body shape. Truss measurements were important to quantify and discriminate changing body shape, presumably due to changing environmental conditions. Sexual dimorphism was not observed and juveniles could be distinguished from adults based on their body shape. More importantly, M. surmuletus occurring in different geographical areas could be differentiated using this method. Based on pRDA, a significant difference of head morphological dimensions was observed between populations occurring in the eastern English Channel and those occurring in the Bay of Biscay, suggesting that fish from these areas could represent two subpopulations.

Alterations in the antioxidant defense system in prepubertal children with a history of extrauterine growth restriction.

PURPOSE: The role of oxidative stress is well known in the pathogenesis of acquired malnutrition. Intrauterine growth restriction has been associated with an imbalance in oxidative stress/antioxidant system. Therefore, early postnatal environment and, consequently, extrauterine growth restriction might be associated with alterations in the antioxidant defense system, even in the prepubertal stage. METHODS: This is a descriptive, analytical, and observational case-control study. The study included two groups; 38 Caucasian prepubertal children born prematurely and with a history of extrauterine growth restriction as the case group, and 123 gender- and age-matched controls. Plasma exogenous antioxidant (retinol, ß-carotene, and α-tocopherol) concentrations were measured by HPLC; antioxidant enzyme activities of catalase, glutathione reductase, glutathione peroxidase, and superoxide dismutase were determined in lysed erythrocytes by spectrophotometric techniques. RESULTS: Catalase and glutathione peroxidase concentrations were significantly lower in extrauterine growth restriction children than in controls (P < 0.001). Lower plasma retinol concentrations were found in the case group (P = 0.029), while concentrations of ß-carotene and α-tocopherol were higher (P < 0.001) in extrauterine growth restriction prepubertal children as compared with controls. After correction by gestational age, birth weight, and length, statistically significant differences were also found, except for retinol. CONCLUSIONS: Prepubertal children with a history of extrauterine growth restriction present alterations in their antioxidant defense system. Knowing these alterations may be important in establishing pharmacological and nutritional treatments as this situation might be associated with higher metabolic disorders in adulthood.

Prepubertal children with suitable fitness and physical activity present reduced risk of oxidative stress.

To assess the impact of fitness status and physical activity on oxidative stress in prepubertal children, we measured selected biomarkers such as protein carbonyls (PC), lipid peroxidation products, and total nitrites, as well as the antioxidant system: total glutathione (TG), oxidized glutathione (GSSG), reduced glutathione (GSH), superoxide dismutase activity, and glutathione peroxidase. A total of 132 healthy children ages 7-12, at prepubertal stage, were classified into two groups according to their fitness level: low fitness (LF) and high fitness (HF). They were observed while engaged in an after-school exercise program, and a questionnaire was created to obtain information on their physical activity or sedentary habits. Plasma and red blood cells were obtained to analyze biomarkers. Regarding oxidative stress markers, the LF group and the sedentary group showed higher levels of TG and GSSG and a lower GSH/GSSG ratio than the HF group and the children engaged in physical activity. A negative association was found between PC and GSSG and TG and between TG and the GSH/GSSG ratio. Moreover, a negative correlation was found between GSSG and fitness, with a positive correlation with the GSH/GSSG ratio. TG, GSSG, and the GSH/GSSG ratio seem to be reliable markers of oxidative stress in healthy prepubertal children with low fitness or sedentary habits. This research contributes to the recognition that an adequate level of fitness and recreational physical activity in childhood leads to better health and oxidative status.

[Metabolic changes in prepuberty children with extrauterine growth restriction]. / Alteraciones metabólicas en prepúberes con retraso del crecimiento extrauterino.

INTRODUCTION: Extrauterine growth restriction (EUGR) is associated with severe nutritional deficit during the first weeks of life, which, as intrauterine growth restriction, may lead to metabolic anomalies in later stages of life. PATIENTS AND METHODS: A group of 38 prepuberty children with a history of EUGR were selected, along with a control group of 123 children with similar age and gender. Perinatal stage was assessed in the EUGR group. Anthropometric parameters, blood pressure, serum biochemical markers of carbohydrate metabolism, and lipid profile were measured in both groups. RESULTS: The EUGR group had height and body mass index values significantly lower than in the control group (P<.001) and higher systolic and diastolic blood pressure (P<.001). The majority (70%) of EUGR children were below the 50th percentile for weight and height, and 55% were below the 25th percentile for body mass index (P<.001), as well as 46% and 37% above the 95% percentile for systolic and diastolic blood pressure, respectively (P<.001). The EUGR group had higher glucose levels (P<.001) and lower high density lipoprotein cholesterol (HDLc) (P<.001) than the control group, although without clinical relevance. CONCLUSIONS: Children with a history of EUGR have anthropometric, blood pressure and metabolic alterations in the prepuberty stage. It would be desirable to control the nutrition they receive in the perinatal period, and follow them up in childhood as alterations may occur in the future.

[Clinical characteristics of patients with infection due to Influenza A (H1N1) 2009 and critical pathology]. / Características clínicas de pacientes con infección por Influenza A (H1N1) 2009 y patología crítica.

OBJECTIVE: Retrospective, observational study in children hospitalized due to Influenza A (H1N1) between October 2009 and February 2010, emphasizing on those who required intensive therapy. MATERIAL AND METHODS: Risk factors, symptoms, course, complications, mortality, time of disappearance of RT-PCR Influenza A (H1N1), average length of stay and duration of treatment with oseltamivir, were studied, comparing critically ill patients (group I) with the rest of hospitalized patients (group II). RESULTS: A total of 38 children, with a mean age of 5.03±4.6 years were admitted during the study period. Six patients required intensive care, 83.3% had risk factors for influenza A (H1N1) compared with 62.5% in group II. Fever > 38°C was the predominant symptom (92.1%). Respiratory symptoms were significantly more frequent in group I (83.3% vs. 33.6; P<.01). Two critically ill patients required mechanical ventilation due to ARDS (acute respiratory distress syndrome). One patient with exacerbation of chronic respiratory failure responded favourably to high-flow oxygen. One patient developed fulminant myocarditis and required ECMO (Extracorporeal Membrane Oxygenation) because of secondary cardiogenic shock, which developed into multiple organ dysfunction and brain death. Oseltamivir therapy was given for an average of 8.6 days in group I and 4.5 days in group II (P<.05), checking the negativity of RT-PCR Influenza A (H1N1) in 7±2 days. The average stay was significantly higher in group I. Two patients admitted to PICU died. CONCLUSIONS: The presence of risk factors increases the likelihood of unfavourable outcome: high mortality among patients requiring intensive care. Monitoring of RT-PCR Influenza A (H1N1) could help establish the duration of isolation measures.

Toxoplasmosis and genotyping of Toxoplasma gondii in Macropus rufus and Macropus giganteus in Argentina.

Toxoplasma gondii infection is frequently asymptomatic; however, it can be severe or even fatal to some hosts. In this study, diagnosis of disseminated toxoplasmosis in one red kangaroo (Macropus rufus) and one great grey kangaroo (Macropus giganteus) from the La Plata Zoo, Argentina and the isolation and molecular characterization of T. gondii are reported. Both male kangaroos showed depression and sudden death. Toxoplasma gondii infection was diagnosed by fresh examination, histopathology, immunohistochemistry, PCR and bioassay in mice. During fresh examination many protozoan cysts were observed in diaphragm, heart and hind limb muscles of M. rufus. Cysts were also observed in samples from M. giganteus, although in lower number. Cysts from both kangaroos stained strongly with T. gondii anti-serum by immunohistochemistry. The M. rufus showed more considerable histopathological lesions like non-suppurative meningoencephalitis, myositis and myocarditis. All mice inoculated with tissues from both kangaroos developed IFAT titers to T. gondii (titer >or=800) and brain cysts at necropsy. Both T. gondii isolates were maintained by mice passages and the M. rufus isolate was also maintained in cell culture. Toxoplasma gondii DNA from tissue samples was analyzed by PCR-RFLP analysis using the markers 5'SAG2, 3'SAG2, BTUB, GRA6, SAG3, c22-8, L358, PK1, c29-2 and Apico. Genotyping revealed that the T. gondii isolate from M. rufus was clonal type III and the isolate from M. giganteus was clonal type II. This is the first report of disseminated toxoplasmosis in M. rufus and M. giganteus in Argentina caused by genotypes of T. gondii considered non-virulent in a mouse model.

The role of hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) in the treatment of peritoneal carcinomatosis in recurrent ovarian cancer

BACKGROUND AND OBJECTIVES: Peritoneal carcinomatosis in women frequently has an ovarian origin. Hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) along with radical surgery/peritonectomy could present a new therapeutic approach with curative intention. The purpose of this research is to evaluate the role of the administration of HIPEC. METHODS: A series of patients (N=26) diagnosed with peritoneal carcinomatosis for recurrent epithelial ovarian cancer (stage III) from January 1997 to December 2004 submitted to radical surgery/peritonectomy with optimal cytoreduction (R0-R1) were included in this study, 14 treated with HIPEC and 12 without HIPEC. RESULTS: The variables age, histologic type, peritonectomy procedures, peritoneal cancer index (PCI) and lymph node affectation were similar in both groups. The 5-year global survival was 58% and 17% (p=0.046), and 67% and 29% in patients with maximal cytoreduction (R0) (p=0.264), in the HIPEC- and non-HIPEC-treated patients, respectively. In patients with optimal cytoreduction and partial peritonectomy, 5-year global survival was also superior in the HIPEC group (75% vs. 11%, p=0.011). Average time free of disease was superior in the HIPEC group (48+/-42 vs. 24+/-21 months), with less reinterventions due to a new reappearance during the first three evolutionary years (2/14 vs. 4/12). Postoperative morbidity did not show substantial differences in both groups and there was no surgical mortality. CONCLUSIONS: HIPEC is a complement to radical surgery/ peritonectomy, which has been shown to be a surgical procedure with high tolerability, low morbimortality, enhanced survival and prolonged disease-free interval in patients with peritoneal carcinomatosis for recurrent ovarian cancer (AU)

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[Fat inside the dural sheath of lumbar nerve roots in humans]. / Grasa dentro de los manguitos durales de las raíces nerviosas de la columna lumbar humana.

OBJECTIVES: Epidural fat deposition, which varies at different levels of the vertebral column, generates a reservoir from which retained lipophilic substances could be redistributed. The aim of the study was to determine whether fat is deposited within or underneath the dural sheath or whether it is only found within the epidural space, outside the sheath. MATERIAL AND METHODS: Samples of dural sheath from the lumbar spine of human cadavers aged 65 to 72 years were analyzed by scanning electron microscopy. RESULTS: The dural sheaths were made up of an arachnoid layer and a dura mater with a thickness of 100 to 150 microm. A large number of adipocytes were observed between the layers of the dura mater as well as beneath it. CONCLUSIONS: Fat similar to that found in the peripheral nerves is present within and underneath the dural sheaths. The fat found in the dural sheaths would be in close contact with the axons of the nerve roots, unlike the fat contained in the epidural space. The release of lipophilic substances from the fat in the dural sheath could have a greater effect on the nerve roots due to the limited distance that separates the fat from the axons as well as to the poor vascular clearance.

[Epidural fat in various diseases: contribution of magnetic resonance imaging and potential implications for neuro axial anesthesia]. / La grasa epidural en diferentes patologías. Aportaciones de la resonancia magnética y posibles implicaciones en la anestesia neuroaxial.

Epidural fat is a reservoir of lipophilic substances that cushions the pulsatile movements of the dural sac, protects nerve structures, and facilitates the movement of the dural sac over the periosteum of the spinal canal during flexion and extension. Excessive epidural fat can compress the underlying structures, however, and affect the placement of catheters and the distribution of injected solutions. This review discusses changes in epidural fat related to various diseases and events: lipomatosis, epidural lymphoma, arachnoid cysts, epidural hematoma, meningiomas, angiolipomas, spondylolysis, scoliosis, spinal stenosis, and liposarcoma. Also discussed are the sequencing and protocols for magnetic resonance imaging that enable epidural fat to be observed and distinguished from neighboring structures. The relevance of epidural fat in spinal surgery is considered. Finally, we discuss the possible anesthetic implications of the abnormal deposition of epidural fat, to explain the unexpected complications that can arise during performance of epidural anesthesia.

[Characteristics and distribution of normal human epidural fat]. / Características y distribución de la grasa epidural humana normal.

Epidural fat provides sufficient cushion for the pulsatile movements of the dural sac, protects nerve structures, facilitates the movement of the dural sac over the periosteum of the spinal column during flexion and extension, and forms a pharmacologic reservoir of lipophilic substances. We review epidural fat and related structures, including their development during the fetal period when the epidural space is filled by undifferentiated loose, areolar mesenchymal tissue that surrounds the dural sac. In the adult, epidural fat has a continuous distribution and follows a certain metameric pattern. It is located mainly on the dorsal side of the epidural space, where it is organized in triangular capsules joined to the midline of the ligamentum flavum by a vascular pedicle. We consider the distribution of epidural fat in the axial and sagittal planes; its presence in the anterior, lateral and posterior epidural space; its presence in the cervical, thoracic and lumbar portions of the spinal column; and its characteristics and variations according to differing body habits and sex. Finally, we speculate on the possible anesthetic implications of epidural fat in terms of the pharmacokinetics of drugs injected into the epidural space and the tasks of locating the epidural space and inserting an epidural catheter during anesthetic procedures.

Effectiveness of reducing infliximab dose interval in non-responder patients with refractory spondyloarthropathies. An open extension of a multicentre study.

OBJECTIVE: To evaluate the therapeutic effectiveness of reducing the infliximab dose interval to 6 weeks in spondyloarthropathy patients not responding to 5 mg/kg every 8 weeks. METHODS: After 30 weeks of infliximab therapy, 25 patients were classified as responders [Bath Ankylosing Spondylitis Activity Index (BASDAI) <4 cm or ESR <30 mm/h and CRP <5 mg/l, n = 15; group A] or non-responders (patients who did not achieve the response established for group A; n = 10; group B). Responders continued on 5 mg/kg every 8 weeks and non-responders decreased the dose interval to 6 weeks. BASDAI, Bath Ankylosing Spondylitis Functional Index (BASFI), ESR, CRP and ankylosing spondylitis assessment (ASAS) criteria were used to assess response. RESULTS: At 62 weeks, 11 of 15 patients (73.3%, 95% confidence interval = 44.9-92.2%) from group A and three of 10 patients (30%, 95% confidence interval = 6.7-65.2) from group B were responders (P = 0.049). Eighty per cent (eight of 10 patients from group A) and 22.2% (two of 9 patients from group B) achieved 50% BASDAI improvement (P = 0.023), and nine of 11 patients (81.8%) and four of 10 (40%) from groups A and B, respectively, reached ASAS20 at 62 weeks (P = 0.08). CONCLUSION: Patients on infliximab 5 mg/kg every 8 weeks with persistent disease activity may benefit from reducing the dose interval to 6 weeks.

[Possibility of cauda equina nerve root damage from lumbar punctures performed with 25-gauge Quincke and Whitacre needles]. / Posibilidad de lesión en las raíces nerviosas de la cola de caballo en relación con las punciones lumbares realizadas con agujas 25-G Quincke y Whitacre.

OBJECTIVE: To assess the possibility of puncturing nerve roots in the cauda equina with spinal needles with different point designs and to quantify the number of axons affected. MATERIAL AND METHODS: We performed in vitro punctures of human nerve roots taken from 3 fresh cadavers. Twenty punctures were performed with 25-gauge Whitacre needles and 40 with 25-gauge Quincke needles; half the Quincke needle punctures were carried out with the point perpendicular to the root and the other half with the point parallel to it. The samples were studied by optical and scanning electron microscopy. The possibility of finding the needle orifece inserted inside the nerve was assessed. On a photographic montage, we counted the number of axons during a hypothetical nerve puncture. RESULTS: Nerve roots used in this study were between 1 and 2.3 mm thick, allowing the needle to penetrate the root in the 52 samples studied. The needle orifice was never fully located inside the nerve in any of the samples. The numbers of myelinized axons affected during nerve punctures 0.2 mm deep were 95, 154, and 81 for Whitacre needles, Quincke needles with the point held perpendicular, or the same needle type held parallel, respectively. During punctures 0.5 mm deep, 472, 602, and 279 were affected for each puncture group, respectively. The differences in all cases were statistically significant. CONCLUSIONS: It is possible to achieve intraneural puncture with 25-gauge needles. However, full intraneural placement of the orifice of the needle is unlikely. In case of nerve trauma, the damage could be greater if puncture is carried out with a Quincke needle with the point inserted perpendicular to the nerve root.

Ultrastructural findings in human spinal pia mater in relation to subarachnoid anesthesia.

UNLABELLED: We examined ultrastructural details such as the cellular component and membrane thickness of human spinal pia mater with the aim of determining whether fenestrations are present. We hypothesized that pia mater is not a continuous membrane but, instead, that there are fenestrations across the pial cellular membrane. The lumbar dural sac from 7 fresh human cadavers was removed, and samples from lumbar spinal pia mater were studied by special staining techniques, immunohistochemistry, and transmission and scanning electron microscopy. A pial layer made by flat overlapping cells and subpial tissue was identified. We found fenestrations in samples from human spinal pia mater at the thoracic-lumbar junction, conus medullaris, and nerve root levels, but these fenestrations did not appear at the thoracic level. We speculate whether the presence of fenestrations in human spinal pia mater at the level of the lumbar spinal cord and at the nerve root levels has any influence on the transfer of local anesthetics across this membrane. IMPLICATIONS: The ultrastructural anatomy of the human pia mater, such as pial cells, membrane thickness, and subpial tissue at different levels of the thoracic and lumbar spinal cord and nerve roots, was studied by special staining techniques, immunohistochemistry, and transmission and scanning electron microscopy. Fenestrations were found in samples at the thoracic-lumbar junction, conus medullaris, and nerve root levels. No fenestrations were found in samples at the thoracic level. At present, we cannot determine the significance of these findings.