Robotically assisted nerve and facet blocks: a cadaveric study

RATIONALE AND OBJECTIVES: This study was performed to evaluate the feasibility of using a joystick-controlled robotic needle driver to place a 22-gauge needle for nerve and facet blocks. MATERIALS AND METHODS: Biplane fluoroscopy and a robotic needle driver were used to place 12 needles into the lumbar paraspinal region of an embalmed female cadaver (age at death, 98 years). Small metal BB nipple markers (1 mm in diameter) were inserted percutaneously to serve as targets. Six needles were then placed near the nerve root, and six were placed near the facet root. Anteroposterior and lateral radiographs were obtained after each needle placement to assess its accuracy. RESULTS: All needles were placed within 3 mm of the target BB. The average distance was 1.44 mm +/- 0.66 (standard deviation). DISCUSSION: A robotic needle driver can be used to place needles accurately in the nerve and facet regions. Clinical studies are required to investigate the advantages and disadvantages of this system for interventional procedures involving needles.     

Age dependence of tolerance to anoxia and changes in cytosolic calcium in rabbit renal proximal tubules

Calcium(Ca²⁺)-dependent processes mediate, in part, anoxic cell injury. These may account for the difference in sensitivity to anoxia between certain immature and mature renal cells. To address this question, we studied the effects of anoxia on cytosolic free Ca²⁺ concentration ([Ca²⁺]_i), cell integrity, and transport functions in microdissected proximal convoluted tubules (PCT) of <3-week-old (newborn) and >12-week-old (adult) rabbits. Tubules were loaded with 10 μM fura-2 AM by incubation for 60 min at 37°C, and then superfused with isosmotic saline solution gassed with either 95%O₂-5%CO₂ (control group) or 95%N₂-5%CO₂ (anoxia group) for 30 min. [Ca²⁺]_i was measured ratiometrically; cell damage was assessed by nuclear binding of propidium iodide (PI). Anoxia resulted in a fourfold increase in [Ca²⁺]_i in adult tubules (from resting values of 245±10 to 975±100 nM, P <0.001), whereas in newborn tubules the rise was significantly less (from resting values of 137±5 to 165±5 nM, P <0.001 between anoxic groups). Transient exposure to 100 mM potassium chloride, which depolarizes the PCT cells, induced increases in [Ca²⁺]_i from baseline, to 920±90 nM in tubules from adult and to 396±16 nM in those from newborn rabbits (P <0.001 between age groups). After exposure to ligands such as parathyroid hormone (PTH) and ATP, [Ca²⁺]_i increased in both newborn and adult tubules, but to lower levels in newborn tubules. The response to PTH and ATP was transient in both age groups, [Ca²⁺]_i returning to baseline levels after 2 min. Following anoxia, tubules from adult animals exhibited staining of all cell nuclei by 1 min exposure to PI, indicative of gross permeabilization of the cells. Nuclei of anoxic immatures tubules did not stain with PI. The sodium-dependent uptakes of a glucose analogue (¹⁴C-α-methyl-glucopyranoside) and phosphate (³²Pi) were preserved in agarose-filled tubules of newborns after anoxia, whereas in those of adults recovery from anoxia was associated with drastic reduction in the uptake of these solutes. Overall, our results suggest that: (1) during anoxia, cell Ca²⁺ rises to critical levels in PCTs of adults compared with those of <3-week-old animals, (2) Ca²⁺ influx occurs via a pathway activated by exposure to high [K⁺]_o, presumably voltage-sensitive Ca²⁺ channels or reversal of Na⁺-Ca²⁺ exchange, (3) these pathways are either less active or less abundant in proximal tubules of newborn compared with adult rabbits, and (4) secondary active transport activity and cellular integrity are well preserved after anoxia in PCT cells of newborn but not of adult rabbits. Received June 27, 1995; received in revised form December 1, 1995; accepted December 8, 1995     

Motion detection and correction for dynamic 15O-water myocardial perfusion PET studies

Purpose Patient motion during dynamic PET studies is a well-documented source of errors. The purpose of this study was to investigate the incidence of frame-to-frame motion in dynamic ¹⁵O-water myocardial perfusion PET studies, to test the efficacy of motion correction methods and to study whether implementation of motion correction would have an impact on the perfusion results.Methods We developed a motion detection procedure using external radioactive skin markers and frame-to-frame alignment. To evaluate motion, marker coordinates inside the field of view were determined in each frame for each study. The highest number of frames with identical spatial coordinates during the study were defined as non-moved. Movement was considered present if even one marker changed position, by one pixel/frame compared with reference, in one axis, and such frames were defined as moved. We tested manual, in-house-developed motion correction software and an automatic motion correction using a rigid body point model implemented in MIPAV (Medical Image Processing, Analysis and Visualisation) software. After motion correction, remaining motion was re-analysed. Myocardial blood flow (MBF) values were calculated for both non-corrected and motion-corrected datasets.Results At rest, patient motion was found in 18% of the frames, but during pharmacological stress the fraction increased to 45% and during physical exercise it rose to 80%. Both motion correction algorithms significantly decreased (p<0.006) the number of moved frames and the amplitude of motion (p<0.04). Motion correction significantly increased MBF results during bicycle exercise (p<0.02). At rest or during adenosine infusion, the motion correction had no significant effects on MBF values.Conclusion Significant motion is a common phenomenon in dynamic cardiac studies during adenosine infusion but especially during exercise. Applying motion correction for the data acquired during exercise clearly changed the MBF results, indicating that motion correction is required for these studies.     

Acute massive gastric dilatation: severe ischemia and gastric necrosis without perforation

Acute massive gastric dilatation is a rare event and though it can occur in a multitude of medical conditions, its pathogenesis is still debated. It leads almost invariably to gastric necrosis with or without perforation which calls for emergency surgical treatment. We present the case of a 22 year-old male patient of normal weight with acute massive gastric dilatation due to a binge eating episode leading to gastric parietal ischemia with mucosal necrosis. Abdominal computed tomography established the diagnosis of acute massive gastric dilatation. After partial decompression of the stomach, the patient emptied his stomach by vomiting. Eight hours after gastric decompression, an upper endoscopy was performed showing ischemia with areas of necrotic gastric mucosa in the fundus and along the greater curvature. Despite presence of ischemia and gastric necrosis, conservative treatment was successful. Psychiatric assessment revealed a borderline mentally retarded young man, but no current diagnosis of a typical eating disorder. Physicians should be aware that binge eating habits may cause acute massive gastric dilatation in patients of normal weight who are not diagnosed as having a typical eating disorder. Prompt diagnosis of acute gastric dilatation and decompression of the stomach even when gastric ischemia and mucosal necrosis is present, may avoid unnecessary laparotomy.     

Emergency signs in oro-facial traumatology in children and adolescents

Based on an analysis of the literature concerning the children and adolescents with dental trauma to primary and permanent teeth, the treatment is multidisciplinary, requiring surgical, orthodontic, operative and prosthetic compliance. Periodic check-up is essential. These guidelines are intended as an aid to the dentist in the management and treatment of traumatized teeth and should be revised as soon as more evidence about the effect of treatment delay becomes available.     

Plasmolemmal potassium gradient does not affect lung protection by an ATP-regulated potassium channel opener

BACKGROUND: We have previously shown that metabolic arrest induced with ATP-regulated potassium channel openers (PCOs) can improve lung preservation by adding Aprikalim (a PCO, Rhone-Poulene Roher) to modified Euro-Collins solution for pulmonary artery flush. Because the membrane hyperpolarizing effects of a PCO potentially competes with the depolarizing effects of a hyperkalemic solution, this study evaluated the effects of the potassium gradient on PCO-mediated lung protection. STUDY DESIGN: Twenty rabbits underwent lung protection in four groups. Group 1 underwent harvest and reperfusion as a "no ischemia" control. Groups 2, 3, and 4 underwent harvest followed by 18 hours of cold ischemic storage before reperfusion. Groups 1 and 4 received Euro Collins as the pulmonary flush at induction of ischemia. Group 2 received Euro Collins plus Aprikalim (100 microM); and group 3 received lactated Ringer's plus Aprikalim. After ischemic storage, the lungs were reperfused with autologous blood for 2 hours. Every 30 minutes, the lungs were given a 10-minute 100% fractional inspired oxygen (F(i)O(2)) challenge to measure maximal gas exchange as an indication of graft function. RESULTS: Repeated measures ANOVA showed Aprikalim improved graft function after 18 hours of cold ischemia (p < 0.0001). No significant differences were found when Aprikalim was used in either Euro-Collins (group 2) or lactated Ringer's (group 3) solution. CONCLUSIONS: The ability of the PCO Aprikalim to preserve gas exchange in a model of hypothermic pulmonary ischemia-reperfusion injury was not affected by the plasmolemmal potassium gradient. This is consistent with recent findings in myocardial protection studies that the protective effects of PCOs may be intracellular.     

Capillary haemangioma of the nasal cavity in a 7-week-old baby--successful treatment using intralesional steroid injection

A case of a seven-week-old baby who presented with a capillary haemangioma of the nasal cavity is presented. We describe a novel treatment modality and provide a literature review of head and neck capillary haemangioma in the paediatric population. Capillary haemangioma of the nasal cavity and our treatment option has not previously been described in the literature at such an early age.