Surgical techniques: Stereoelectroencephalography-guided radiofrequency-thermocoagulation (SEEG-guided RF-TC).

Stereoelectroencephalography-guided radiofrequency-thermocoagulation (SEEG-guided RF-TC) consists of coupling SEEG investigation with RF-TC stereotactic lesioning directly through the recording electrodes. In this systematic review the surgical technique, indications, and outcomes are described. Maximum accuracy is reached when a frame-based procedure with a robotic assistance and a per-operative vascular X-ray imaging are performed. Monitoring of the lesioning procedure based on the impedance, a sharp modification of which indicates that the thermocoagulation has reached its maximum volume, allows the optimization of the lesion size. The first indication concerns patients in whom a SEEG is required to determine whether surgery is feasible and in whom resection is indeed possible. Even if surgery is performed owing to insufficient efficacy of SEEG-guided RF-TC, the procedure remains interesting owing to its high positive predictive value for good outcome after surgery. The second indication concerns patients in whom phase I non-invasive investigations have concluded to surgical contraindication and who may still undergo SEEG in a purely therapeutic perspective (small deep zones inaccessible to surgery and network nodes of large epileptic networks). Lastly, SEEG-guided RF-TC can be considered as a first-line treatment for periventricular nodular heterotopia (PNH). Independently of indication, the overall seizure-free rate is 23% and the responder rate is 58%. The best results are obtained for PNH (38% seizure-free and 81% responders), while the worst results have been reported for temporal lobe-epilepsy in a dedicated study. The overall complication rate is 2.5%. More evidence is needed to help determine the exact place of SEEG-guided RF-TC in the surgical management algorithm.

Invasive evaluation in children (SEEG vs subdural grids).

Designed from the 60s to the 80s for adults, and despite the development of many new techniques, invasive explorations still have indications in children with focal drug-resistant epilepsy. The main types are stereoelectroencephalography (SEEG) and subdural explorations (SDE). They provide precise information on the localization of the epileptogenic zone (EZ), its relationships with eloquent cortex, and the feasibility of performing a tailored surgical resection. Thermocoagulations, which are a diagnostic and therapeutic tool, can be performed using SEEG electrodes. Both techniques are feasible in children, with an age limitation for SEEG (which requires a bone thickness above 2 mm). The complication rate is higher with SDE. Opposed for a long time and never compared in a systematic study, they should presently be considered complementary. The indications cannot be directly inferred from those for adults, as there are pediatric particularities in the seizures' semiology, functional areas, imaging and urgent situations. We successively discuss the choice in individual cases of SEEG or SDE respectively, the specific problematic in infancy and early childhood, the schema in SEEG for cryptogenic epilepsies (in particular insular), the particularities of polymicrogyria and deeply located lesions, and finally, SEEG designed for thermocoagulations. Future improvements should include more accurate implantation schemas thanks to advanced non-invasive explorations and possibilities to perform SEEG in infants.

French guidelines on stereoelectroencephalography (SEEG).

Stereoelectroencephalography (SEEG) was designed and developed in the 1960s in France by J. Talairach and J. Bancaud. It is an invasive method of exploration for drug-resistant focal epilepsies, offering the advantage of a tridimensional and temporally precise study of the epileptic discharge. It allows anatomo-electrical correlations and tailored surgeries. Whereas this method has been used for decades by experts in a limited number of European centers, the last ten years have seen increasing worldwide spread of its use. Moreover in current practice, SEEG is not only a diagnostic tool but also offers a therapeutic option, i.e., thermocoagulation. In order to propose formal guidelines for best clinical practice in SEEG, a working party was formed, composed of experts from every French centre with a large SEEG experience (those performing more than 10 SEEG per year over at least a 5 year period). This group formulated recommendations, which were graded by all participants according to established methodology. The first part of this article summarizes these within the following topics: indications and limits of SEEG; planning and management of SEEG; surgical technique; electrophysiological technical procedures; interpretation of SEEG recordings; and SEEG-guided radio frequency thermocoagulation. In the second part, those different aspects are discussed in more detail by subgroups of experts, based on existing literature and their own experience. The aim of this work is to present a consensual French approach to SEEG, which could be used as a basic document for centers using this method, particularly those who are beginning SEEG practice. These guidelines are supported by the French Clinical Neurophysiology Society and the French chapter of the International League Against Epilepsy.

Feasibility of thermocoagulation in a screen-and-treat approach for the treatment of cervical precancerous lesions in sub-Saharan Africa.

BACKGROUND: The use of thermocoagulation for the treatment of cervical precancerous lesions has recently generated a great deal of interest. Our aim was to determine the feasibility of this outpatient procedure in the context of a cervical cancer (CC) screen-and-treat campaign in sub-Saharan Africa. METHODS: Between July and December 2015, women living in the area of Dschang (Cameroon) aged between 30 and 49 years, were enrolled in a CC screening study. HPV self-sampling was performed as a primary screening test and women who were either "HPV 16/18/45-positive" or "positive to other HPV types and to VIA" were considered screen-positive, thus requiring further management. The primary outcome was the percentage of screen-positive patients who met the criteria to undergo thermocoagulation. The secondary outcome was the assessment of the procedure's side effects immediately after treatment and at the 1-month follow-up visit. RESULTS: A total of 1012 women were recruited in the study period. Among 121 screen-positive women, 110 of them (90.9%) were eligible to be treated with thermocoagulation. No patients discontinued treatment because of pain or other side effects. The mean ± SD (Standard Deviation) score measured on the 10-point Visual Analogue Scale (VAS) was 3.0 ± 1.6. Women having less than 2 children were more likely to report a higher pain score than those with more than two (4.2 ± 2.0 versus 2.9 ± 1.5, respectively; p value = 0.016). A total of 109/110 (99.1%) patients came to the 1-month follow-up visit. Vaginal discharge was reported in 108/109 (99.1%) patients throughout the month following treatment. Three patients (2.8%) developed vaginal infection requiring local antibiotics. No hospitalizations were required. CONCLUSION: The majority of screen-positive women met the criteria and could be treated by thermocoagulation. The procedure was associated to minor side effects and is overall feasible in the context of a CC screen-and-treat campaign in sub-Saharan Africa. TRIAL REGISTRATION: The trial was retrospectively registered on November 11, 2015 with the identifier: ISRCTN99459678 .

Recurrence of cervical intraepithelial lesions after thermo-coagulation in HIV-positive and HIV-negative Nigerian women.

BACKGROUND: The burden of cervical cancer remains huge globally, more so in sub-Saharan Africa. Effectiveness of screening, rates of recurrence following treatment and factors driving these in Africans have not been sufficiently studied. The purpose of this study therefore was to investigate factors associated with recurrence of cervical intraepithelial lesions following thermo-coagulation in HIV-positive and HIV-negative Nigerian women using Visual Inspection with Acetic Acid (VIA) or Lugol's Iodine (VILI) for diagnosis. METHODS: A retrospective cohort study was conducted, recruiting participants from the cervical cancer "see and treat" program of IHVN. Data from 6 sites collected over a 4-year period was used. Inclusion criteria were: age ≥18 years, baseline HIV status known, VIA or VILI positive and thermo-coagulation done. Logistic regression was performed to examine the proportion of women with recurrence and to examine factors associated with recurrence. RESULTS: Out of 177 women included in study, 67.8 % (120/177) were HIV-positive and 32.2 % (57/177) were HIV-negative. Recurrence occurred in 16.4 % (29/177) of participants; this was 18.3 % (22/120) in HIV-positive women compared to 12.3 % (7/57) in HIV-negative women but this difference was not statistically significant (p-value 0.31). Women aged ≥30 years were much less likely to develop recurrence, adjusted OR = 0.34 (95 % CI = 0.13, 0.92). Among HIV-positive women, CD4 count <200cells/mm(3) was associated with recurrence, adjusted OR = 5.47 (95 % CI = 1.24, 24.18). CONCLUSION: Recurrence of VIA or VILI positive lesions after thermo-coagulation occurs in a significant proportion of women. HIV-positive women with low CD4 counts are at increased risk of recurrent lesions and may be related to immunosuppression.

Electrocautery device does not provide adequate pulmonary vessel sealing in transumbilical anatomic pulmonary lobectomy.

INTRODUCTION: Safe pulmonary vessel sealing device plays a crucial role in anatomic lung resection. In 2014, we reported high rates of massive bleeding complications during transumbilical lobectomy in a canine model due to difficulty in managing the pulmonary vessel with an endostapler. In this animal survival series, we aimed to evaluate the outcome of pulmonary vessel sealing with an electrocautery device to simplify the transumbilical thoracic surgery. METHODS: Under general anesthesia, a 3-cm longitudinal incision was made over the umbilicus. Under video guidance, a bronchoscope was inserted through the incision for exploration. The diaphragmatic wound was created with an electrocautery knife and used as the entrance into the thoracic cavity. Using the transumbilical technique, anatomic lobectomy was performed with electrosurgical devices and endoscopic vascular staplers in 15 canines. RESULTS: Transumbilical endoscopic anatomic lobectomy was successfully completed in 12 of the 15 animals. Intraoperative bleeding developed in three animals during pulmonary hilum dissection, where one animal was killed due to hemodynamic instability and the other two animals required thoracotomy to complete the operation. There were five delayed bleeding and surgical mortality cases caused by inadequate vessel sealing by electrosurgical devices. Postmortem examination confirmed correct transumbilical lobectomy in the twelve animals that survived the operations. CONCLUSION: Transumbilical anatomic lobectomy is technically feasible in a canine model; however, the electrosurgical devices were not effective in sealing the pulmonary vessel in the current canine model.

Diagnostic accuracy of sonohysterography vs hysteroscopy in benign uterine endocavitary findings.

OBJECTIVE: To compare diagnostic accuracy of sonohysterography vs hysteroscopy in patients with benign uterine endocavitary findings. PATIENTS AND METHODS: This retrospective study evaluated 202 patients submitted to sonohysterography after transvaginal ultrasound examination suspicious for uterine endocavitary findings. Cytological sample was taken and analyzed from the fluid used to distend the uterine cavity. Of 202 patients enrolled for this study, 86 patients underwent gynaecological surgery, of whom 77 were treated with operative hysteroscopy and 9 with other gynaecological surgical techniques. Statistical analysis was performed to evaluate diagnostic agreement between sonohysterography vs hysteroscopy and cytology vs histology. RESULTS: Diagnostic concordance between sonohysterography and hysteroscopy was significant (k value 0.87). The correlation between cytological and histological findings had a moderate level of concordance (k value 0.49). CONCLUSIONS: Sonohysterography provides a diagnostic accuracy as well as hysteroscopy, therefore, it could be considered an alternative procedure in the diagnosis of benign uterine endocavitary findings.

Tonsillitis.

INTRODUCTION: The definition of severe recurrent throat infections is arbitrary, but recent criteria have defined severe tonsillitis as: five or more episodes of true tonsillitis a year; symptoms for at least 1 year; and episodes that are disabling and prevent normal functioning. Diagnosis of acute tonsillitis is clinical, and it can be difficult to distinguish viral from bacterial infections. Rapid antigen testing has a very low sensitivity in the diagnosis of bacterial tonsillitis, but more accurate tests take longer to deliver results. Bacteria are cultured from few people with tonsillitis. Other causes include infectious mononucleosis from Epstein-Barr virus infection, cytomegalovirus, toxoplasmosis, HIV, hepatitis A, and rubella. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical question: What are the effects of tonsillectomy in children and adults with acute recurrent or chronic throat infections? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2014 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). RESULTS: We found 15 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. CONCLUSIONS: In this systematic review, we present information relating to the effectiveness and safety of the following interventions: cold-steel tonsillectomy and diathermy tonsillectomy.

A perioperative management algorithm for cardiac rhythm management devices: the PACED-OP protocol.

BACKGROUND: Limited data are available regarding the perioperative management of cardiac rhythm management devices (CRMDs) exposed to intraoperative electromagnetic interference. We postulated that implementation of a simple, standardized approach to CRMD management using our own institution's Pacing And Cardioverting Electronic Devices peri-Operative Protocol (the PACED-OP protocol) would be associated with a reduction in the amount of device reprogramming without an increase in CRMD-related complications. METHODS: Records of patients with CRMDs undergoing 497 consecutive surgical procedures were analyzed retrospectively. Roughly half (51%, n = 254) of these procedures occurred before implementation of the PACED-OP protocol, when patients were generally treated according to the American Society of Anesthesiologists' 2005 guidelines. These cases were compared to the remaining surgeries that occurred after implementation of the PACED-OP protocol. Records were screened for evidence of intraoperative CRMD malfunction that was directly associated with the use of electrocautery. Postoperative complications that could be indirectly or possibly linked to electrocautery-mediated CRMD malfunction were also identified. RESULTS: Implementation of the PACED-OP protocol was associated with a significant reduction in the odds of device reprogramming (adjusted odds ratio [aOR] 0.19, P < 0.001). There was no direct evidence of CRMD malfunction in either cohort. The rate of postoperative complications that could be indirectly or possibly linked with electrocautery-mediated CRMD damage did not differ significantly between cohorts (aOR = 1.37, 95% confidence interval 0.56-3.3, P = 0.49). CONCLUSION: The PACED-OP protocol implementation was associated with a significant reduction in the odds of device reprogramming without a significant difference in the odds of CRMD-related complications.

Application of high frequency bipolar electrocoagulation LigaSure™ in appendix vermiformis of rabbits with or without acute inflammatory process.

PURPOSE: To evaluate the efficacy of the use of LigaSure™ in appendectomy, with or without acute inflammatory process, and to compare with simple ligature and conventional therapy. METHODS: A total of 30 rabbits (Oryctolagus cuniculus) randomly allocated in two groups, group A and B, of 15 animals each were used. The group A without acute appendicitis and the group B with acute appendicitis were submitted to appendectomy. After, the groups were subdivided into three groups, each group containing five rabbits submitted to simple ligature, conventional therapy and application of LigaSure™. We assessed macroscopic and microscopy parameters of appendiceal stump and operative wound. RESULTS: The group with acute appendicitis that LigaSure™ was applied had fibrosis in 100% of animals, as well as in the other operative techniques used. It suggested that application of LigaSure™ is efficient as other techniques used in healing of appendiceal stump. CONCLUSIONS: The application of LigaSure™ induces the formation of fibrosis in the appendiceal stump. The technique proved efficacy to induce enough fibrous tissue to obstruct leakage of enteric content.

Application of high frequency bipolar electrocoagulation LigaSureTM in appendix vermiformis of rabbits with or without acute inflammatory process / Aplicação do eletrocoagulador bipolar de alta frequência LigaSureTM no apêndice vermiforme na vigência ou não de processo inflamatório agudo

PURPOSE: To evaluate the efficacy of the use of LigaSureTM in appendectomy, with or without acute inflammatory process, and to compare with simple ligature and conventional therapy. METHODS: A total of 30 rabbits (Oryctolagus cuniculus) randomly allocated in two groups, group A and B, of 15 animals each were used. The group A without acute appendicitis and the group B with acute appendicitis were submitted to appendectomy. After, the groups were subdivided into three groups, each group containing five rabbits submitted to simple ligature, conventional therapy and application of LigaSureTM. We assessed macroscopic and microscopy parameters of appendiceal stump and operative wound. RESULTS: The group with acute appendicitis that LigaSureTM was applied had fibrosis in 100% of animals, as well as in the other operative techniques used. It suggested that application of LigaSureTM is efficient as other techniques used in healing of appendiceal stump. CONCLUSIONS: The application of LigaSureTM induces the formation of fibrosis in the appendiceal stump. The technique proved efficacy to induce enough fibrous tissue to obstruct leakage of enteric content.

OBJETIVO: Avaliar a eficácia da utilização do LigaSureTM na apendicectomia, com ou sem a presença de processo inflamatório agudo, comparando com ligadura simples ou técnica tradicional. MÉTODOS: Um total de 30 coelhos (Oryctolagus cuniculus) foi alocado em dois grupos, grupos A e B, cada um composto por 15 animais. O grupo A não apresentava apendicite aguda e o grupo B com apendicite aguda, sendo os animais submetidos à apendicitectomia. Cada grupo foi divido em três subgrupos, cada um com cinco animais onde foram então submetidos à ligadura simples, técnica tradicional ou utilização do LigaSureTM. Foram avaliados parâmetros macroscópicos assim como microscópicos do coto apendicular assim como da ferida operatória. RESULTADOS: No grupo que apresentava apendicite aguda onde foi utilizado o LigaSureTM, foi observado fibrose em 100% dos animais, assim como nos outros dois grupos. Com isto mostrou-se que a aplicação do LigaSureTM é tão eficiente quanto as outras técnicas utilizadas na cicatrizaçãoo do coto apendicular. CONCLUSÕES: A utilização do LigaSureTM induz a formação de fibrose na região do coto apencicular. A técnica foi eficaz quanto à formação de tecido fibrótico evitando o extravassamento de conteúdo entérico.

Total mesorectal excision--does the choice of dissection technique have an impact on pelvic autonomic nerve preservation?

BACKGROUND: The aim of this experimental study was to assess the quality of pelvic autonomic nerve preservation of different dissection techniques. MATERIAL AND METHODS: Twelve pigs underwent low anterior rectal resection (LARR) with scissors, ultracision, monopolar diathermy, and waterjet, each in three animals. Assessment of pelvic autonomic nerve preservation was carried out by stimulation of the pelvic splanchnic nerves under electromyography of the internal anal sphincter (IAS). Neurostimulation was performed bilaterally after posterior dissection, after complete mesorectal dissection, and after rectal resection. RESULTS: Stimulation resulted in significantly increased amplitudes of the time-based electromyographic signal of the IAS, confirming nerve preservation. The stimulation results after complete mesorectal dissection showed comparable median amplitude increases for dissection with scissors (10.34 µV (interquartile range [IQR], 5.58; 14.74)) and ultracision (9.79 µV (IQR, 7.63; 11.6)). Lower amplitude increases were observed for monopolar diathermy (4.47 µV (IQR, 2.52; 10.46)) and waterjet (0.61 µV (IQR, 0.07; 2.11)) (p = 0.038). All animals undergoing dissection with scissors, ultracision, and monopolar diathermy had bilateral positive results. Of three animals undergoing LARR with waterjet, one had bilateral positive results. Two had unilateral negative results, indicating incomplete nerve preservation. CONCLUSION: Scissors, ultracision, and monopolar diathermy might have comparable nerve-sparing potentials and differed from waterjet.

Comparison of ultrasonically activated scalpel and traditional technique in radial artery harvesting; an electron microscopic evaluation.

OBJECTIVE: Use of the radial artery (RA) as a conduit in coronary artery bypass grafting (CABG) has become increasingly popular in recent years. The aim of this prospective randomized study is to determine how the endothelial wall and blood flow of RA are differently affected with the usages of ultrasonic scalpel and conventional electrocautery in addition to effects of hypothermia and storage solutions. Histopathologic study was achieved by electron microscope to evaluate endothelium of the grafts. METHODS: Between 2008 and 2009, 182 patients with coronary artery diseases were operated for coronary artery revascularization. The radial arteries were harvested for 40 of these patients and divided into two groups depending on the use of the ultrasonic cautery (UC) (n=20) and the high-frequency electrocautery (EC) (n=20). Patients were divided into two subgroups according to the storage media of the graft. RA was preserved in situ at room temperature (Group 1) and normothermic organ bath (NOB) (Group 2). Harvesting time, use of hemostatic clips, frequency of spasm, in situ free flow, temperature and endothelial damage were compared between the two groups. Statistical analysis was performed using one-way ANOVA, Friedman and unpaired t tests. RESULTS: In all groups, blood flows were significantly decreased as parallel to the local temperatures. Second and third phase flows were similar in group EC1 and UC1 (p>0.05). Free flow was increased in group UC+NOB when comparing with only EC group (60.4±9.83 ml/min and 40.8±7.50 ml/min, p<0.001), whereas the graft preparing time "t2" was shorter in group EC than UC (10.9±2.42 min and 15.2±1.31 min, p<0.01). Nonetheless scoring of the groups in terms of endothelial cell structure and mitochondrial morphological changes did not show any significant difference. CONCLUSION: If endothelial integrity of the RA can be preserved along with the application of systemic temperature (NOB), regardless of harvesting technique, it provides better flow rates.

Design development of an electrocoagulation reactor for molasses process wastewater treatment.

The impact of electrode corrosion behaviour, reactor geometry and current density on electrocoagulation efficiency were investigated for the treatment of molasses process wastewater. Two laboratory-scale vertical plate electrocoagulation reactors were used for this investigation: the first being a low aspect ratio bath reactor with a low specific electrode area, while the other was a high aspect ratio column reactor with a high specific electrode area. Anomalous anodic dissolution and cathodic corrosion of the aluminium electrodes both contributed significantly to overall metal consumption. Increasing specific electrode area and aspect ratio each led to improved treatment efficiency, whereas the impact of current density was more complicated involving the combined influences of several competing effects. The space-time yields of coagulant and bubbles (both functions of specific electrode area, current density and current efficiency) were found to influence mixing within the reactor and thus treatment efficiency.

Electrocoagulation for the treatment of textile wastewaters with Al or Fe electrodes: compared variations of COD levels, turbidity and absorbance.

Electrocoagulation technique has been used for the treatment of two wastewaters issued by textile industry. Treatment was carried out in a discontinuous system provided with aluminium or iron electrodes, and with recirculation of the liquid. The efficiency of the technique was followed depending on the electrode material in terms of water treatment, current efficiency of the dissolution, cell voltage, energy consumption to reach the same COD or turbidity abatement: regardless of the quality of the phase separation in the flocculation section downstream of the electrocoagulation cell, the two metals were found to be of comparable efficiency. Besides COD and absorbance were shown to follow similar, regular variations along the treatment; experimental data could be interpreted by a simple model involving the overall equilibrium between the metal dissolved--in the form of hydroxides--and the polluting substance. Abatement of the waste turbidity was observed to obey another law, with a sharp reduction of turbidity after a preliminary phase, where accumulation of metal hydroxide has no effect on this variable.

[Comparison between bipolar cautery dissection and classic dissection techniques in tonsillectomy]. / Tonsillektomide bipolar koter diseksiyon ve klasik diseksiyon tekniklerinin karsilastirilmasi.

OBJECTIVES: We compared the results of tonsillectomy performed by classical dissection and bipolar cautery dissection in pediatric patients. PATIENTS AND METHODS: A total of 201 pediatric patients were randomly assigned to two tonsillectomy groups. Ninety-five patients (62 boys, 33 girls; mean age 7+/-3 years) underwent bipolar cautery tonsillectomy, and 106 patients (58 boys, 48 girls; mean age 8+/-3 years) underwent classical dissection tonsillectomy. Patients were compared with respect to bleeding during tonsillectomy, operation time, tonsil volumes, primary and secondary bleeding, severity of pain at the first hour and on the tenth day, and time to first solid food intake. RESULTS: With bipolar cautery tonsillectomy, the mean operation time, amount of perioperative bleeding, and pain score at the first hour were significantly lower (p<0.001). However, the mean pain score on the tenth day was significantly higher with cautery tonsillectomy, which significantly prolonged initiation of solid food intake (p<0.001). There were no significant differences between the two groups with respect to tonsil volumes and initiation of cold fluid nutrition at the third postoperative hour (p>0.05). In the late postoperative period, one patient in each group required intervention under general anesthesia to control bleeding. CONCLUSION: Merits and demerits of both techniques should be taken into consideration for appropriate patient selection for the two tonsillectomy methods.

Surgical management of spinal cord haemangioblastoma.

BACKGROUND: The surgical management of spinal cord haemangioblastomas is distinct from that of other benign spinal cord tumours and optimal surgical strategy is still being determined because of the rarity of the condition. The aim of this study is to investigate factors that affect the outcome of surgical management. PATIENTS AND METHODS: We retrospectively analysed 24 operations for symptomatic spinal cord haemangioblastomas in 20 patients. Clinical features and surgical results were investigated by medical record review, telephone interviews, angiographic images, and magnetic resonance images (MRI). The mean follow-up period was 5.6 years (range 6 months to 13.6 years). RESULTS: Patients with cystic components showed pre-operative motor weakness and sensory change more commonly than those without cystic components. Post-operative function scale had a positive correlation with pre-operative function (R(2) = 0.727; p < 0.001) and no correlation with the extent of the surgery. All subtotally removed tumours recurred, whereas totally removed tumours recurred in only 3 patients. CONCLUSION: The cystic component of spinal cord haemangioblastomas is responsible for symptom generation and is helpful for dissecting tumours. Post-operative functional status is determined by pre-operative functional status. Total removal is feasible by using the correct surgical technique and is recommended to prevent recurrence.

In vitro testing of current spread during ventricular catheter coagulation using diathermy. Technical note.

The authors report on the development of an anterior cerebral artery pseudoaneurysm that hemorrhaged after monopolar coagulation for a ventricular catheter lodged in the interhemispheric fissure. After observing this complication, the authors developed a simple bench test that can be performed by any neurosurgeon to determine the safest coagulation parameters for any given diathermy unit. A modified grounding pad was placed in a beaker of a protein solution consisting of egg whites. Ventricular catheters were then placed in the solution, and a monopolar diathermy current was applied to a metal stylet at various wattages and for different durations of time. Inducing coagulation at 40 W with a diathermy unit produced flames emanating from around the pores of the catheter tip. Flash flames were also observed at 35 W, forming a coagulum of egg white for a distance of up to 1 cm from the catheter tip. All heat was dissipated through the holes of the first 16 mm of the catheter. At 20 W the flame was minimal and coagulation appeared adequate, whereas at 15 W only bubbles were seen around the tip together with suboptimal coagulum formation. This technique is a simple and effective means of determining the optimal setting for monopolar diathermy and can be used to figure the optimal catheter coagulation wattage for a given diathermy unit. Considering the results of this study, the authors have lowered the current for coagulation in ventricular catheters to 20 W.

In vitro study of the safety limits of bronchoscopic argon plasma coagulation in the presence of airway stents.

OBJECTIVE AND BACKGROUND: The purpose of this study was to identify the safety limits of bronchoscopic argon plasma coagulation (APC) around indwelling airway stents. METHODOLOGY: This is an experimental in vitro study simulating a patient-care environment. Uncovered and covered Nitinol (Ultraflex), uncovered and covered Wallstent and studded silicone stents were deployed in the tracheobronchial tree of a ventilated and oxygenated heart-lung block from an expired pig. APC was performed at power settings of 40 and 80 W using F(I)O(2) of 0.21, 0.40 and 1.00 and an argon gas-flow rate of 0.8 L/min through a flexible fiberoptic bronchoscope. The primary outcome was the time taken for the APC to cause stent damage. Stent damage was defined as discoloration, ignition or rupture. RESULTS: Airway fires involving all five stents consistently occurred in the presence of 100% oxygen at powers of 40 W and 80 W. At lower F(I)O(2) (0.21 and 0.40) silicone stents were not damaged at 40 W and 80 W. Uncovered Ultraflex stents were undamaged using 40 W at either F(I)O(2) (0.21 and 0.40), but could be damaged using both F(I)O(2) levels when the power was increased to 80 W. Covered Ultraflex and both uncovered and covered Wallstents were damaged at both power settings (40 W and 80 W) and F(I)O(2) (0.21 and 0.40) levels, with a trend towards earlier damage using higher F(I)O(2) and power. CONCLUSION: Working within the parameters identified in this study (power 40 W, F(I)O(2) 0.21, APC flow-rate 0.8 L/min), APC is a safe method for tissue devitalization and destruction and avoids the risk of airway stent ignition, especially if short bursts of APC are employed. The safety limits identified using an F(i)O(2) of 0.4, however, are also important because some patients undergoing resection may require oxygen therapy.