Macroscopic Quality Control Improves the Reliability of Blue Dye–Only Sentinel Lymph Node Biopsy in Breast Cancer

Background: One of the problems of sentinel lymph node (SLN) biopsy is the risk of false negatives. At the Institut Curie, to reduce the false-negative rate, we have developed a histological quality control of the SLN performed by blue dye alone, which consists of verification of the SLN blue stain by the pathologist.Methods: A total of 324 patients underwent an SLN biopsy procedure with patent blue dye only followed by an immediate axillary dissection. Initially, SLNs were checked to ensure that they were blue by macroscopic examination. Finally, a search for immunohistochemistry micrometastasis was performed.Results: In 277 (85.5%) of 324 patients, an SLN was identified by the surgeon. After standard examination, the false-negative rate was 11.1% (10 of 90). After macroscopic checking of the 197 negative SLNs, 167 of the 197 were confirmed blue, and there were 5 false negatives, which brought the false-negative rate down to 5.6% (5 of 90). Sixty SLNs out of the 167 confirmed blue SLNs were then proved to be immunohistochemically micrometastatic, and there were 3 false negatives, giving a final false-negative rate of 2.2% (2 of 90; P = .002).Conclusions: In this series, the procedure of pathologic analysis of the SLN has resulted in a significant reduction of the false-negative rate.     

Limitations using the vacuum-assist venous drainage technique during cardiopulmonary bypass procedures

Vacuum-assist venous drainage (VAVD) can increase venous blood return during cardiopulmonary bypass (CPB) procedures. However, the negative pressure created in the closed cardiotomy reservoir can be transmitted to the oxygenator if a nonocclusive or centrifugal arterial pump is used, resulting in bubble transgression (BT) from the gas to blood compartment of the oxygenator. We analyzed the vacuum pressure required to produce BT using an in vitro circuit including successively a closed reservoir, a pump (centrifugal or roller), and an oxygenator. A constant hydrostatic pressure was maintained onto the oxygenator. Vacuum was applied on the cardiotomy reservoir, progressively increasing negative pressure from 0 to -80 mmHg and monitoring BT with a bubble detector. Six different oxygenators were compared. A partially occlusive roller pump and a centrifugal pump were compared to a control, which was without any pump. A mean negative pressure of -53 +/- 7 mmHg was necessary to produce BT in all the oxygenators in the absence of a pump. The presence of a centrifugal pump between the reservoir and the oxygenator significantly increased the negative pressure required to produce BT compared to the control (-67 +/- 7 mmHg, p < .05). No bubbles were detected using the roller pump (> -80 mmHg needed for BT), thus statistically significant when compared to the centrifugal pump (p < .05). The centrifugal pump offers significant resistance to BT but not as much compared to the roller pump, though BT cannot be prevented if the pump is turned off while the vacuum remains on the reservoir. Therefore, VAVD is a safe technique as long as the perfusionist stops the vacuum when the arterial pump is no longer in use.     

Plasticity in Action of Intrathecal Clonidine to Mechanical but Not Thermal Nociception after Peripheral Nerve Injury

Background: Intrathecal clonidine reduces tactile allodynia in animal models of neuropathic pain, and this effect is blocked by atropine. However, the role of tonic spinal cholinergic activity and its interaction with [alpha]2-adrenergic systems in normal and neuropathic conditions and to different sensory methods has not been systematically examined. The authors examined cholinergic receptor involvement in thermal and mechanical sensitivity in normal and neuropathic animals and its interaction with intrathecal clonidine.

Methods: Normal rats and rats that received L5/L6 spinal nerve ligation were tested with acute radiant heat, paw pressure, and punctate mechanical stimulation before and after the intrathecal administration of saline, the muscarinic receptor antagonist, atropine, or a toxin to destroy cholinergic neurons, and then after intrathecal clonidine.

Results: Atropine, the cholinergic neuronal toxin, and saline did not alter baseline withdrawal thresholds. In nerve-injured rats, neither saline nor atropine altered antinociception from clonidine to a thermal stimulus, but atropine reduced the effect of clonidine to von Frey filament withdrawal threshold (34 +/- 5.6 vs. 14 +/- 5.8 g [mean +/- SEM], saline vs. atropine;P < 0.05) and to withdrawal threshold to paw pressure after clonidine (174 +/- 18 g vs. 137 +/- 16 g, saline vs. atropine;P < 0.05).     

Clonidine as an adjuvant to intrathecal local anesthetics for surgery: systematic review of randomized trials

BACKGROUND AND OBJECTIVES: Clonidine is added to intrathecal local anesthetics to improve intraoperative analgesia and to increase the duration of sensory and motor block. The aim of this systematic review is to quantify beneficial and harmful effects of clonidine when used as an adjuvant to intrathecal local anesthetics for surgery. METHODS: We included data from 22 randomized trials (1,445 patients) testing a large variety of doses of clonidine, added to intrathecal bupivacaine, mepivacaine, prilocaine, or tetracaine. RESULTS: Clonidine 15 to 150 microg prolonged in a linear, dose-dependent manner, the time to 2 segment regression (range of means, 14 to 75 minutes) and the time to regression to L2 (range of means, 11 to 128 minutes). The time to first analgesic request (median 101 minutes, range 35 to 310) and of motor block (median 47 minutes, range 6 to 131) was prolonged without evidence of dose-responsiveness. Time to achieve complete sensory or motor block, and extent of cephalic spread remained unchanged. There were fewer episodes of intraoperative pain with clonidine (relative risk, 0.24; 95% confidence interval [CI], 0.09-0.64; number needed to treat, 13) but more episodes of arterial hypotension (relative risk, 1.81; 95% CI 1.44-2.28; number needed to harm, 8) without evidence of dose-responsiveness. The risk of bradycardia was unchanged. CONCLUSIONS: This study may serve as a rational basis to help clinicians decide whether or not to combine clonidine with an intrathecal local anesthetic for surgery. The optimal dose of clonidine, however, remains unknown.     

Muscle study in experimental scoliosis in rabbits with costotransversectomy: evidence of ischemic process

Scoliosis involves the central nervous system diseases, ligaments, articulations and skeletal muscles, but there is no consensus on its pathogeny and progression of muscle abnormalities. In this study, we investigate the morphologic changes in the muscle of rabbit submitted to experimental scoliosis, with special emphasis on abnormalities related to blood supply. We studied 26 rabbits subjected to costotransversectomy by pulling out six transverse processes at thoracic level and six rabbits were used as controls. All the animals operated upon developed scoliosis showing an average angle of 29.1° on the 60th day, with its apices located at T4 and T12 when they were subjected to paraspinal muscle biopsy on both sides. The muscle biopsies were subjected to histological stains and histochemical reactions, as well as to a morphometric study. On the concave side, the changes were not statistically significant regarding the control group. On the convex side conjunctive tissue proliferation, infiltration by adipose tissue, central nucleus excess, inflammatory reaction, segmental fibrosis, type 1 fiber hypertrophy, type 2 fiber hypertrophy and atrophic angular dark fibers in the unspecific esterase were statistically significant. The segmental fibrosis reached a circumscribed muscle segment, compatible with an ischemic phenomenon. The histological diagnoses on the concave side of the animals had unspecific alterations (atrophy and hypertrophy) in 13, myopathy in 3, denervation in 3 and normal in 7. The convex side diagnoses were myopathy in 14, denervation in 8, mixed in 3 and normal in 1. The procedure determined morphologic changes on the convex side indicating possible denervation or myopathy of ischemic origin.     

Image-guided laser ablation of osteoid osteoma in pediatric patients

BACKGROUND: We aimed to evaluate the effectiveness of image-guided laser ablation for the treatment of osteoid osteomas in pediatric patients. METHODS: From June 1994 to June 2006, 68 patients aged 3 to 18 years (mean age, 12.1 +/- 4.2 years) with a diagnosis of osteoid osteoma underwent laser ablation in our department. Among them, 3 patients had prior unsuccessful attempt of surgical resection. Procedures were performed under spinal or general anesthesia with combined computed tomographic and fluoroscopic guidance. An 18-gauge needle was placed in the nidus after bone drilling when required, and an optical fiber was inserted through it. An average energy of 1200 J was delivered using an infrared diode laser generator. Patients were discharged the next day and followed up with assessment of pain, medication intakes, and potential complications. Clinical success was defined by complete pain relief without need for medication intake. RESULTS: Technical success was achieved in all but 1 of our first patients, which was subsequently treated by percutaneous resection. Overall clinical success was 98%. Primary clinical success was obtained in 60 patients (88%). In 7 patients, recurrence of symptoms at 4 to 27 months from the initial procedure was managed by repeat laser ablation, resulting in secondary success (10%). No complications related to the procedure were observed. Follow-up ranged 16 to 146 months (mean, 83 months). CONCLUSIONS: Currently, image-guided laser ablation is a safe and effective procedure that can be proposed as the mainstay treatment of osteoid osteomas in pediatrics. LEVEL OF EVIDENCE: Therapeutic case series study level IV.     

Effects of Intermittent Femoral Nerve Injections of Bupivacaine, Levobupivacaine, and Ropivacaine on Mitochondrial Energy Metabolism and Intracellular Calcium Homeostasis in Rat Psoas Muscle

Background: Long-acting local anesthetics cause muscle damage. Moreover, long-acting local anesthetics act as uncoupler of oxidative phosphorylation in isolated mitochondria and enhance sarcoplasmic reticulum Ca2+ release. The aim of the study was to evaluate effects of perineural injections of local anesthetics on mitochondrial energetic metabolism and intracellular calcium homeostasis in vivo.

Methods: Femoral nerve block catheters were inserted in adult male Wistar rats. Rats were randomized and received seven injections (1 ml/kg) of bupivacaine, levobupivacaine, ropivacaine, or isotonic saline at 8-h intervals. Rats were killed 8 h after the last injection. Psoas muscle was quickly dissected from next to the femoral nerve. Local anesthetic concentrations in muscle were determined. Oxidative capacity was measured in saponin-skinned fibers. Oxygen consumption rates were measured, and mitochondrial adenosine triphosphate synthesis rate was determined. Enzymatic activities of mitochondrial respiratory chain complexes were evaluated. Local calcium release events (calcium sparks) were analyzed as well as sarcoplasmic reticulum calcium content in saponin-skinned fibers.

Results: Eight hours after the last injection, psoas muscle concentration of local anesthetics was less than 0.3 [mu]g/g tissue. Adenosine triphosphate synthesis and adenosine triphosphate-to-oxygen ratio were significantly decreased in the muscle of rats treated with local anesthetics. A global decrease (around 50%) in all of the enzyme activities of the respiratory chain was observed. Levobupivacaine increased the amplitude and frequency of the calcium sparks, whereas lower sarcoplasmic reticulum calcium content was shown.     

Gastric Emptying of Solids and Semi-solids in Morbidly Obese and Non-obese Subjects: An Assessment Using the <Superscript>13</Superscript>C-Octanoic Acid and <Superscript>13</Superscript>C-Acetic Acid Breath Tests

Background It has been suggested that obesity is associated with an altered rate of gastric emptying. The objective of the present study was to determine whether the rates of solid and semi-solid gastric emptying differ between morbidly obese patients and lean subjects. Methods The Gastric-emptying time (GET) of solid and semi-solid meals were compared between lean healthy subjects and morbidly obese patients enrolled in two previously published studies. GET of solid and semi-solid meals was measured using the ¹³C-octanoic acid breath test and ¹³C-acetic acid breath test, respectively, in 24 lean and 14 morbidly obese individuals of both sexes. Student t-test was used to compare the mean data between the lean and morbidly obese groups. The influence of sex, gender, BMI and morbid obesity on the GET of solid meals was verified by linear regression analysis. Results Mean t(1/2) values of solid GET (± standard deviation) were 203.6 ±  76.0 min and 143.5 ± 19.1 min for lean and obese subjects, respectively (P = 0.0010). Mean t(lag) values of solid GET were 127.3 ± 42.7 min and 98.4 ± 13.0 min for lean and obese subjects, respectively (P = 0.0044). No significant difference in semi-solid GET was observed between the lean and morbidly obese groups. Conclusion The present study demonstrated a significantly enhanced gastric emptying of the solid meal test in morbidly obese patients when compared to lean subjects. This finding is compatible with the hypothesis that rapid gastric emptying in morbidly obese subjects increases caloric intake due to a more rapid loss of satiety.     

Leakage of 4 resin-based root-canal sealers used with a single-cone technique.

OBJECTIVE: The aim of this study was to measure leakage of 4 resin-based sealers. STUDY DESIGN: Four groups of premolars (n = 60) were prepared using GT Rotary files and the crown-down technique and filled by the single-cone technique with AH26, AHPlus, EndoREZ, and an experimental MBP as sealer. Leakage was measured using the fluid filtration method after 15, 30, and 60 days and determined as microL/min(-1) x 10 psi. RESULTS: Statistical analysis by ANOVA and Tukey HSD test indicated that root fillings with AH Plus and the MBP showed lower leakage values after 15 days (P < .05). At 30 days, AH26 presented higher leakage values when compared to other sealers (P < .05). At 60 days, MBP and AH Plus presented the lower leakage values, differing significantly from EndoREZ (P < .05). CONCLUSION: It was observed that AH Plus and the experimental MBP showed lower leakage after 60 days than AH 26 and EndoREZ.