Avascular Field Research Articles

Mobilization of the outer cavernous membrane decreases bleeding and improves resection in spheno-clinoidal meningiomas without cavernous sinus extension: A randomized controlled trial.

The aim of this study was to determine whether adding mobilization of the outer cavernous sinus membrane as a part of the approach, in large spheno-clinoidal meningiomas without cavernous sinus extension, would reduce bleeding and increase the extent of resection. This prospective randomized controlled trial was held between February 2016 and April 2017 at Cairo University Hospitals. The study recruited 94 patients with spheno-clinoidal meningiomas without cavernous sinus involvement. Patients were randomly assigned (by a computer based randomization system) into two groups; the treatment group, in which the patients received mobilization of the outer layer of the lateral wall of the cavernous sinus, prior to opening of the dura; and, the control group, in which the patients were operated by a direct opening of the dura without cavernous sinus dissection. The primary outcome of this study was the difference in the amount of blood lost during surgery between both groups of patients. The secondary outcome variables were the estimated blood loss (EBL) calculated according to Mercurelli's formula, the extent of tumor resection and the amount of blood transfused. The amount of blood loss and estimated blood loss (EBL) were significantly less in the "with mobilization group" with the P value being 0.00 and 0.013, respectively. Additionally, the amount of residual tumor was compared between both the groups and it showed that the group of patients who have received mobilization of the outer cavernous sinus membrane had a higher rate of radical resection as expressed by a lower volume of residual tumor (P value 0.005). In large spheno-clinoidal meningiomas without cavernous sinus involvement, routine mobilization of the outer cavernous sinus membrane reduces bleeding. This helps in a better visualization of cranial nerves in a relatively avascular field as it enables the performance of neurovascular dissection in an earlier phase of surgery. It also enables a more radical resection.

DCR Local anesthesia (A new technique)

In DCR local anesthesia achieves dual purpose. Firstly, it helps in anesthesia. Secondly, Adrenaline added to the anesthetic agent creates decongestion, which helps in an avascular operation field. The old technique involves an injection of large amount of anesthetic agent, which can result in lignocaine reaction, and adrenaline associated problems. In the new technique only 1.5-2.0 ml of local anesthetic agent is injected which is highly safe and effective. There is also minimal distortion of local anatomy. In this study, two hundred and sixty five patients were given local anesthesia with new technique. Only six needed to have their anesthesia repeated, sixteen had a persistent ooze. No one had adrenaline related problems. This technique is a safe and effective way of providing anesthesia for DCR.

PTU-012 A novel submucosal injection solution: data on safety and efficacy from a large prospective EMR series

Introduction Submucosal injection is an integral part of EMR. The ideal solution will produce a long lasting high elevation, and an avascular field with delineation of tissue planes. This requires a combination of various drugs and solutions. However, no such mix is commercially available. This has resulted in a wide range of mix being used in this country, with no data on the safety, efficacy and long-term results of these solutions. We have developed an ideal mix of gelofusine (colloid) to provide a long lasting lift with adrenaline to reduce the vascularity of the field and indigo carmine to adequately delineate tissue planes. We aim to illustrate the feasibility, safety and efficacy and long-term effects of our novel submucosal lifting solution. Methods The lifting solution was: 500 mls gelofusine, 2 mls 1:1000 adrenaline and 5 mls indigocarmine 0.4%. We reviewed all EMRs since 2005. Records were assessed to collect data on efficacy of the solution, immediate and late mucosal and systemic effects. Data were collected on type and size of lesions, procedure time and volume of solution used. Results A total of 546 lesions were removed. 411 polypectomies and 135 upper GI EMRs. Volume used was between 5-250 mls, dependent on lesion size and procedure time (range 20 min–180 min). Distribution of upper GI lesions: 99 oesophageal EMRs, 20 gastric EMRs and 16 duodenal EMRs. Endoscopic follow-up data were available on 107 cases, with a mean interval of 3 months (range: 2–6 months). There was no evidence of immediate or late complications, including tissue injury, necrosis or stenosis related to the solution. For the lower GI lesions: 411 polyps removed. There were 143 polyps >2 cm in size. Left sided lesions=121 (median 45 mm range 20–150), right sided lesions=22 (median 31 mm, range 20–50). Procedure time 20 min–180 min. There were follow-up data on 117 colonic EMRs, with a mean interval of 4 months (range 0.5–60 months). There was no evidence of any late complications, including tissue injury necrosis or stenosis at the previous polypectomy sites. The endoscopist found the solution extremely effective and provided good lift after one injection in all of the cases examined. There was a short lived 5–20% rise in pulse rate. There were no immediate cardiac complications preventing completion of the procedures. No anaphylaxis or allergic reaction. There was no local or systemic sepsis related to the solution. No obvious renal or hepatic effects reported. Conclusion Largest reported series on submucosal injection solution in the world; Have clearly demonstrated the feasibility and efficacy of this novel injection mix; Shows immediate and long-term safety of this solution; Shows some systemic effects like tachycardia so caution is advised in cardiac patients.

A Novel Technique for the Laparoscopic Management of Interstitial Pregnancy

Cornual or interstitial pregnancy is a rare form of ectopic pregnancy, which if undiagnosed can lead to fatal hemorrhage. Surgical management has the potential risk of major hemorrhage and subsequently the need for hysterectomy. We describe a laparoscopic technique used on two patients on consecutive days to place a tourniquet around the cornu prior to excision of the ectopic gestation in a relatively avascular field. (J GYNECOL SURG 14:85, 1998).

Comparison of dark-field and bright-field incident illumination for in vivo measurements of reduced pyridine nucleotides

Bright-field and dark-field illumination techniques for in vivo measurements of reduced pyridine nucleotide fluorescence were compared in 15 rats during periods of normocapnia, hypocapnia, hypercapnia, and anoxia. Parameters investigated included fluorescence, cortical reflectance, cortical blood flow, and electroencephalograms. In normal brain, with preserved autoregulation, reduced pyridine nucleotide fluorescence was constant through a wide range in P a(CO 2), cortical blood flow, and cerebral blood volume in animals studied using vertical illumination (bright-field) techniques. There was a marked increase in reduced pyridine nucleotide fluorescence at death from anoxia. Artifacts were reduced by monochromators for excitation, emission, and reflected light; low-intensity vertical excitation energy and high-sensitivity recording instrumentation; and a small avascular (123 μm) field. Potential sources of error include photodecomposition, hemoglobin interference from absorption and reflectance, and light scattering. Vertical excitation techniques using a small field appeared to give more reliable and reproducible results than circumferential techniques using a larger field of observation.

The cryoprobe retractor in the microsurgical dissection of tumors

A technique is outlined for retraction of tumors under the operating microscope using the microcyoprobe. The method depends on temperatures settings in the--20 degrees to--30 degrees C range to produce a small ice bond uniting tumor and cryoprobe. No attempt is made to create a solid frozen tumor. The locally avascular field and retraction provided ideal circumstances for microdissection. Examples of this approach are outlined with case summaries for spinal cord ependymoma and hemangioblastoma.

Effect of hypocapnia, hypercapnia, and blood pressure on NADH fluorescence, electrical activity, and blood flow in normal and partially ischemic monkey cortex.

Nicotinamide adenine dinucleotide fluorescence, cortical reflectance, cortical blood flow, and electroencephalograms were recorded from squirrel monkey brains before, during, and after focal transient cerebral ischemia produced by the temporary clipping of the middle cerebral artery. After release of the occluding clip, the monkeys were followed through an N2-breathing cycle and then to death from anoxia. The effects of controlled variations in arterial carbon dioxide tensions (PaCO2) and mean arterial blood pressures (MABP) were investigated in normal and in ischemic brain. In normal brain, with preserved autoregulation, NADH fluorescence was constant through a wide range in Paco2, MABP, and cortical blood flow. In ischemic brain, NADH levels increased, correlated closely with decreased cortical blood flow and EEG abnormalities, and became dependent on MABP. Artifacts in fluorescent measurements were reduced by: monochromators for excitation, emission, and reflected light; low intensity vertical excitation energy and high sensitivity recording instrumentation; and a small avascular (123 microns) field.

Intracranial Aneurysms

THE ADVANTAGES of neurosurgical intracranial exposure in an avascular field are obvious. To accomplish this objective, experimental and clinical studies have been made to obtain an avascular surgical field by combining deep hypothermia and total circulatory arrest with the aid of an extracorporeal mechanical circuit and "total heparinization" of the blood. Temporary occlusion of the afferent blood supply prior to clipping of a cerebral aneurysm under moderate hypothermia of 25 to 30 C (77 to 86 F) by cooling of the body surface has been carried out successfully. Yet prolonged occlusion at these temperatures may be attended with serious neurologic sequelae, whether arrest of the arterial blood flow to the brain has been accomplished by simultaneous occlusion of the carotid and vertebral arteries in the neck¹or by application of temporarily placed clips on the circle of Willis.²At these temperatures the dangers of ventricular fibrillation are a

Barbwire Tendon Suture

Early experiences with the barb wire tendon suture have proved it to be simple and easy to use. This suture, as previously described, seems ideal for applying the basic principles of tendon surgery. Further experiences with this technique indicate that this suture will continue to be a useful supplement for the treatment of severed flexor tendons. The purpose of this paper is to present results encountered and impressions derived from the repair of 30 consecutive freshly severed flexor tendons. The results are graded as good, fair, and poor by criteria previously expressed.* TECHNIQUE The routine preparation of the patient, as pointed out by Bunnell 3 and others, was followed. The freshly severed tendons were sutured as soon as possible in the operating room under sterile conditions. Brachial block or a general anesthetic was used. An avascular field was secured by pneumatic tourniquet. Sharp technique was used and all basic principles

Use of controlled hypotension in large blood vessel surgery.

CONTROLLED hypotension has been used extensively in this country and abroad as a means of providing a relatively avascular field for surgical procedures. Three general methods of producing hypotension have been used: arteriotomy, total sympathetic blockade by high spinal anesthesia, and ganglionic blockade. Of the three methods the latter is the most physiologically sound and one of the most widely used. Until recently hexamethonium compounds have been generally employed but had the disadvantage of too prolonged vasodilation. Therefore a shorter-acting drug was sought, and recently the experimental and clinical use of a thiophanium derivative * to produce controlled hypotension has been reported.† Our interest in the use of controlled hypotension as an aid to large blood vessel surgery developed as a result of difficulty in the surgical management of two patients with exceptionally large patent ductus. The experience with one of these patients has been previously reported. 4 In that instance