Thermal Spread Research Articles

Stability analysis of the pickup ion ring-beam distributions in the outer heliosheath

ABSTRACT The electromagnetic instabilities driven by the pickup ions in the outer heliosheath play a crucial role in interpreting the energetic neutral atom (ENA) ribbon observed by the Interstellar Boundary EXplorer (IBEX). Previous studies on the stability of the outer heliosheath pickup ions focused on ring-like velocity distributions with pickup angles equal or close to 90°. In this study, we investigate the instabilities driven by a ring-beam velocity distribution of the pickup ions in the outer heliosheath using linear instability analysis. The modes propagating along (both parallel and antiparallel to) the background magnetic field are examined, and the emphasis is on how the instabilities change with the pickup angle, α, varying from zero to 90°. The parallel thermal spread of the pickup ions is chosen to make the plasma parameters lie in the Alfvén cyclotron ‘stability gap’ to exclude the well-studied Alfvén cyclotron instability. Our linear instability analysis reveals that the unstable modes all have left helicity but may propagate parallel or antiparallel to the background magnetic field. At small α, the parallel-propagating modes are unstable in two separate wavenumber (and frequency) ranges. The two unstable ranges merge into one when α increases to 82°. In addition, the antiparallel-propagating modes become unstable when α is above 5°, but the parallel-propagating modes have larger growth rates until α becomes larger than αc = 82.8°. The growth rates of the parallel-propagating modes quickly drop below zero when α goes beyond αc, while the antiparallel-propagating modes remain unstable until α approaches 90°.

COMPARISON OF ADVANCED BIPOLAR TISSUE FUSION TECHNOLOGY (LIGASURE™) HEMORRHOIDECTOMY VERSUS CONVENTIONAL MILLIGAN MORGAN HEMORRHOIDECTOMY

Background: Conventional hemorrhoidectomy is a common surgical procedure which associated with postoperative morbidities such as pain, urine retention, postoperative bleeding and anal stenosis. The use of the Ligasure™ could result in decreased incidence of postoperative pain and complications as it has minimal thermal spread and limited tissue burn. Objective: To evaluate hemorrhoidectomy using advanced bipolar electrocautery tissue fusion technology (LigaSure™) versus conventional Milligan-Morgan technique by monopolar diathermy. Patients and methods: This prospective study included sixty patients scheduled for elective hemorrhoidectomy at Al-Azhar University Hospitals (El-Hussen and Bab Al-sha'reia University Hospitals), Department of Surgery. All sixty patients were divided in two equal comparative groups: Group A underwent conventional Milligan-Morgan hemorrhoidectomy and group B underwent Ligasure™ hemorrhoidectomy. Data of the sixty patients of the study was collected by the mean investigator himself from January 2020 to September 2020, then the analysis of the data was followed by different statistical methods. Such as the chronological presentation, the percentages, the arithmetic averages, and the t test. The data of the study were analyzed by statistical program SPSS, then Microsoft Excel sheets used to graph the results and integrated into Microsoft Word. Results: Ligasure™ hemorrhoidectomy has a major improvement over the conventional technique. Technically, the Ligasure™ method was much simpler and can be safely carried out by relatively inexperienced junior surgeons. In comparison with conventional hemorrhoidectomy, Ligasure™ hemorrhoidectomy had less operating time (17.28 vs 9.85 minutes, p value <0.001) and had less intraoperative blood loss (65 vs. 17 ml, p value: <0.001). The post-operative pain was lesser in Ligasure™ than conventional hemorrhoidectomy. Post procedure complications such as bleeding (3.5% vs 10%), urinary retention (10% vs 20%) and wound infection (14% vs 20%) were all lower in the Ligasure™ group, and shorter postoperative hospital-stay (1.4 vs 3.2 days). Conclusion: Ligasure™ hemorrhoidectomy was a suture less hemorrhoidectomy technique to achieve tissue and vessel sealing. It was safe, simple and effective, with less intraoperative bleeding, postoperative discomfort and other complications in comparison to conventional hemorrhoidectomy.

Mach number dependence of ion-scale kinetic instability at collisionless perpendicular shock: Condition for Weibel-dominated shock

We investigate ion-scale kinetic plasma instabilities at the collisionless shock using linear theory and nonlinear particle-in-cell (PIC) simulations. We focus on the Alfvén ion cyclotron (AIC), mirror, and Weibel instabilities, which are all driven unstable by the effective temperature anisotropy induced by the shock-reflected ions within the transition layer of a strictly perpendicular shock. We conduct linear dispersion analysis with a homogeneous plasma model to mimic the shock transition layer by adopting a ring distribution with finite thermal spread to represent the velocity distribution of the reflected ions. We find that, for wave propagation parallel to the ambient magnetic field, the AIC instability at lower Alfvén Mach numbers tends to transition to the Weibel instability at higher Alfvén Mach numbers. The instability property is, however, also strongly affected by the sound Mach number. We conclude that the instability at a strong shock with Alfvén and sound Mach numbers both in excess of ∼20–40 may be considered as Weibel-like in the sense that the reflected ions behave essentially unmagnetized. Two-dimensional PIC simulations confirm the linear theory and find that, with typical parameters of young supernova remnant shocks, the ring distribution model produces magnetic fluctuations of the order of the background magnetic field, which is smaller than those observed in previous PIC simulations for Weibel-dominated shocks. This indicates that the assumption of the gyrotropic reflected ion distribution may not be adequate to quantitatively predict nonlinear behaviors of the dynamics in high Mach number shocks.

Application of a Scanner-Assisted Carbon Dioxide Laser System for Neurosurgery

Despite potential advantages, broad carbon dioxide (CO2) laser diffusion in neurosurgery was historically prevented by several operative limitations. Nonetheless, in recent decades, significant improvements, in particular the development of surgical scanners, have made CO2 laser surgery easier and reproducible. The aim of this study was to report our preliminary experience with the SmartXide2 CO2 laser system. The SmartXide2 laser system is a CO2 laser with a radiofrequency-excited laser source, a surgical scanner, and a high-precision micromanipulator, which are connected to the surgical microscope. Ten different brain and spinal tumors were treated to evaluate the laser system potential in different neurosurgical scenarios. Four illustrative cases were presented. The CO2 laser was used together with the traditional instruments in every step of the procedures, from the initial pial incision (intra-axial tumors) or early debulking (extra-axial lesions), to progressive tumor removal, and, lastly, for surgical cavity hemostasis. No injury to the surrounding neurovascular structures was observed. Postoperative neuroimaging confirmed complete tumor removal and showed a marked reduction of preoperative surrounding edema without signs of cerebral/medullary contusions. In selected cases, the SmartXide2 CO2 laser system could be a helpful, reliable, and safe surgical instrument to treat different cerebral and spinal lesions. It addresses some of the limitations of laser systems and is able to cut/ablate and coagulate the tissue simultaneously, with minimal lateral thermal spread, preserving the surrounding eloquent neurovascular structures. Moreover, having no consumable accessories, it is also cost-effective.

The Thermal Safety Profile of a New Bipolar Vessel Sealing Device for Thyroid Surgery

Introduction: Bipolar electrocautery devices used to achieve intraoperative hemostasis carry risk of imparting thermal energy to adjacent tissue, leading to postoperative morbidity. The aim of this study was to compare a new vessel sealing device, the CoolSeal™ Reveal (Bolder Surgical, Louisville, Colorado), with an established industry standard device, the LigaSure™ Exact Dissector (Valleylab, Boulder, Colorado), to assess their safety and the extent to which they impart thermal damage to tissue during thyroid surgery. Materials and Methods: Vascular bundles associated with the thyroid gland in anesthetized sheep were exposed and sealed with a single activation of each device and excised en bloc. Additionally, vascular structures of the sheep were also sealed 0, 1, or 2mm adjacent to the recurrent laryngeal nerve (RLN). Vascular and RLN samples were processed for histopathologic evaluation and assessed for extent of thermal injury, seal width, and coagulative changes. Results: The mean thermal injury extent across all sample sizes and vessel types was significantly lower for the CoolSeal™ Reveal device (547.2 ± 27.9μm) compared to the LigaSure™ device (802.7± 48.6μm) (p&lt;0.001). Seal widths were significantly smaller in samples sealed with the CoolSeal™ Reveal device (899.0 ± 14.9μm) than samples sealed with the LigaSure™ device (1645.3 ± 160.3μm) (p&lt;0.001). Conclusion: The CoolSeal™ Reveal device demonstrates significantly lower thermal spread in vivo compared to the LigaSure™ Exact Dissector. These results indicate that the CoolSeal™ Reveal is an effective tool for sealing blood vessels and minimizing thermal damage to adjacent structures during delicate surgeries or in narrow surgical fields associated with the thyroid gland.

The effect of the plasma density gradient on current filamentation instability

AbstractThe filamentation instability is one of the basic beam‐plasma instabilities that play a significant role in the energy deposition mechanism of the relativistic electrons generated by the laser‐plasma interaction in the fast ignition scenario. In this paper, the effect of the density gradient into plasma on the filamentation instability was investigated in the Weibel unstable plasma, where the plasma temperature anisotropy can play an important role. Results indicated that the density gradient enhances the instability growth rate so that decreasing the density gradient from the critical surface to the core of fuel leads to instability for longer regions in k space. Also, investigations in the region close to the critical surface showed that for decreasing the beam number density nb ≤ 0.01n0, the instability occurs for while this can be different for higher values. Increasing the beam relativistic factor causes a decreasing peak of instability growth rate because of a reduction in beam current, whereas the initial thermal spread of plasma amplifies the filamentation instability.

Robot-assisted laparoscopic heller myotomy using the DaVinci Xi

: Definitive therapy for achalasia remains an esophageal myotomy across the gastroesophageal junction (GEJ). Approaches to myotomy include transthoracic and transabdominal techniques, both open and minimally invasive. Advantages of a transabdominal approach include full access to the stomach below the GEJ for complete myotomy, the angle of approach to the myotomy, and fundoplication. The use of the Da Vinci Xi surgical robot (Intuitive Surgical, Sunnyvale, CA, USA) adds some distinct advantages to the laparoscopic approach. These include: (I) a steady camera with high-definition, three-dimensional view of the circumferential muscle fibers, (II) tremor reduction through the robotic console, (III) wristed instruments providing flexibility in angle of approach and dexterity, and (IV) bi-polar energy use for more delicate, precise fiber division without excessive thermal spread. The advantage of bi-polar energy delivery over monopolar cautery cannot be overstated. We describe our approach to DaVinci Xi Robot-assisted laparoscopic modified heller myotomy with anterior partial fundoplication.

Robot-assisted laparoscopic Nissen fundoplication using the DaVinci Xi

: Anti-reflux surgery remains an important option for treatment of gastroesophageal reflux disease (GERD). Approaches include transthoracic and transabdominal techniques, both open and minimally invasive. Transthoracic approaches are uncommonly performed, generally being limited to use in patients with a hostile abdomen. Transabdominal 360-degree posterior wrap, or Nissen fundoplication, is the most commonly performed anti-reflux operation worldwide. The use of the Da Vinci Xi surgical robot (Intuitive Surgical, Sunnyvale, CA, USA) adds some distinct advantages to the laparoscopic approach. These include: (I) a steady camera with high-definition, stereotactic view, (II) tremor reduction through the robotic console, (III) wristed instruments providing flexibility in angle of approach and dexterity, and (IV) bi-polar energy use for more delicate, precise tissue division without excessive thermal spread. The advantage of bi-polar energy delivery over monopolar cautery cannot be overstated. We describe our approach to DaVinci Xi Robot-assisted laparoscopic Nissen fundoplication.

Modification of the Thermal Spread by the Blade Shape of an Ultrasonically Activated Device.

Few studies have focused on the spread of thermal damage from different blade shapes of ultrasonically activated devices (USADs) used during minimally invasive surgery. In vivo experiments using pig arteries, nerves, and mesentery were used to compare the thermal spread of two different blade types of USADs, non-tapered and tapered, under the same conditions. The tissue temperatures were monitored using a high-resolution infrared thermographic camera and calculated using an image analysis program. The spread of heat denaturation was measured histologically. The temperature was greater at the sides with greater curvature when non-tapered USADs were activated (artery, 1s, 2mm: - 0.92 ± 0.5°C vs. - 0.44 ± 0.5°C, P = 0.022). This effect was more prominent in the tapered type (artery, 1s, 0/1/2mm: 9.14 ± 3.7°C vs. 28.3 ± 16.2°C/0.5 ± 1.4°C vs. 9.76 ± 6.2°C/ - 0.12 ± 0.9°C vs. 1.44 ± 1.9°C, P = 0.044/0.016/0.038, respectively). The temperatures in the tapered USAD were significantly higher at some time- and distance-points than those in a non-tapered USAD (artery, 1s, 0mm, Less/1s, 1mm, Gre: 4.2 ± 2.9°C vs. 9.14 ± 3.7°C /0.36 ± 0.5°C vs. 9.76 ± 6.2°C, P = 0.047/0.027; nerve, 2s, 0mm, Gre: 6.54 ± 3.9°C vs. 17.66 ± 6.2°C, P = 0.012). A three-directional study revealed the thermal spread of the mesentery was greatest at the tip side of the non-tapered type USAD (4.55 ± 2.53°C vs. 12.43 ± 4.03°C/12.43 ± 4.03°C vs. 5.04 ± 1.91°C, P = 0.003/0.005). The thermal spread changed according to the blade shape of the USAD. This knowledge can be applied to more meticulous and complicated procedures, reducing surgical morbidity.

Repeated partial tissue bite with inadequate cooling time for an energy device may cause thermal injury.

Over the past three decades, the use of ultrasonically activated device (USAD) and advanced bipolar device (ABD) has grown in minimally invasive surgeries. However, the thermal profile differences during repeated dissection with different grasping ranges of energy devices, which provide valuable information for preventing thermal injury by energy devices, remain unclear. We developed an ex vivo benchtop model to examine the temperature profile of the blade and jaws of two USADs (HARMONIC® ACE + and Sonicision™) and a ABD (Ligasure™ Maryland) with different grasping ranges (partial tissue and full tissue bite) in repeated dissection with minimum cooling time. The maximum temperature, time required for completion to dissection of 10cm of porcine muscle, thermal spread, and cooling time to reach 60°C were continuously measured using video thermography. In addition, to evaluate one more grasping range "no tissue", we performed a stress test that activated the USAD without tissue intervention to assess the effects of excessive load on the blade and jaw. Repeated dissection of energy devices with minimal cooling time results in high blade and jaw temperatures proportional to the incision distance. In particular, the USADs with partial tissue bite showed a significantly higher temperatures at the blade and jaw, longer cooling times, and higher lateral thermal spread than those with a full tissue bite and the ABD. The stress test with a USAD showed an extremely high blade temperature exceeding 400°C, with the tissue pad melting only 13.2s after activation. Although USAD with partial tissue bite help ensure precise dissection, repeated long activation with inadequate cooling time may increase the risk of thermal injury during surgery. These results suggest that surgeons should use energy devices properly while understanding the risks of adjacent organ damage that could result from abuse of the device.

Electron Gun for the Hollow Beam of a High Power W-Band Extended Interaction Klystron

Results are presented from a theoretical study on optimizing the parameters of an electron gun of a powerful multicavity extended interaction klystron at a frequency of 95 GHz, ensuring the formation of a dense annular electron beam and its transport through interaction region with a current transmission coefficient of 99%, with taking into account of the thermal spread of electron velocities at the cathode.

Thermal Processes in Bile Ducts During Laparoscopic Cholecystectomy with Monopolar Instruments. Experimental Study Using Real-Time Intraluminal and Surface Thermography.

Introduction. A significant rate of complications during laparoscopic cholecystectomy (LC) occurs due to thermal injury caused by monopolar electrosurgery (MES) equipment. Most of them manifest weeks and months after surgery with the common bile duct (CBD) and large duodenal papilla strictures, some in the early postoperative period with bile leaks. Objective. To study thermal processes occurring in the lumen and on the surface of the bile ducts during monopolar coagulation in a porcine model of LC. Methods. The temperature of the bile ducts was measured using instrumentation consisted of biliary stent with temperature sensors, which was inserted in the porcine CBD, signal amplifier, and current sense transformer. Surface temperature was measured with a scientific grade thermal camera. Cholecystectomy was performed using a standard "critical view of safety" (CVS) approach with 5mm monopolar laparoscopic instruments. Results. Application of MES caused significant tissue heating. Lateral thermal spread and the rate of tissue heating depended on the duration of energy application and the initial tissue temperature. In 5 out of 6 experiments, the intraluminal temperature rose up to the critical threshold, and the exposure time ranged from 54 to 560seconds. A sensor positioned at the papilla site was heated in all the experiments but still below the cell damage inducing threshold. The analysis of thermographic charts revealed the presence of the "current channeling" effect and the pedicle effect. Conclusion. There is a possibility of a direct and delayed thermal injury to the bile ducts during LC.

Pattern of thermal damage and tissue carbonisation from endovenous radiofrequency ablation catheter - Using an in vitro porcine liver model.

Successful endovenous thermoablation relies on transmural vein wall ablation. We investigated the pattern of thermal spread and tissue carbonisation from RadioFrequency-induced ThermoTherapy (RFiTT) at different powers and pull back methods, using a porcine liver model. We used a previously validated in-vitro porcine liver model. Different powers from 5-25 W were used to administer 150 J. We compared continuous and pulsed energy delivery. Length, lateral spread, and total area of thermal damage, together with any tissue carbonisation, was measured using digital analysis software. All experiments used 150 J total energy. Total thermal damage area was smaller with lower power and pulsed energy. Continuous energy caused more tissue carbonisation than pulsed except at 25 W. Reduced thermal damage with lower power or pulsed energy results from cooling due to increased time of treatment. Increasing the power increases tissue carbonisation. Optimal treatment is determined by the highest power used continuously that does not cause tissue carbonisation.

Ceiling thermal impingement spread characteristics induced by wall-attached fires under various sub-atmospheric pressures

Ceiling thermal impingement fire spread induced by indoor uncontrollable energy combustion occurred frequently and caused many casualties and property damage. The sub-atmospheric pressure environment has a great impact on uncontrollable energy combustion characteristics of hazardous combustible gaseous fuel fire. China west high-altitude cities develop rapidly due to the economic development, and fire accidents frequently occur. This paper focused on experimentally studying the ceiling fire impingement hazard characteristics induced by wall-attached fires under sub-atmospheric pressures, the various sub-atmospheric pressures (from 55 kPa to 100 kPa), energy heat release rates (from 0.25 kW to 2.5 kW), and source-ceiling heights (0.475 m, 0.38 m, 0.285 m, 0.19 m and 0.095 m) were selected as an variable. The ceiling flame extension lengths of facing and lateral directions were measured and analyzed. Result showed that, the dimensionless ceiling flame extension area is higher in sub-atmospheric pressures. There are many differences between them due to the lower buoyancy in various sub-atmospheric pressures. By accounting for the air entrainment change characterization, it is found that the air entrainment of wall-attached propane jet fire is weaker in sub-atmospheric pressures. The influence of pressure on the flame expansion area is related to the 4/5 power of the ratio of the entrainment coefficient ((α/α100)4/5). And a new model was finally obtained to correlate ceiling flame extension area induced by wall-attached fires with various sub-atmospheric pressures. This work provides can help understand ceiling impingement flow and hazard characteristics under various sub-atmospheric pressures.

Robotic Extraperitoneal Para-Aortic and Pelvic Lymphadenectomy with the Aid of the Double Bipolar Method

Study Objective To evaluate the efficacy of robotic extraperitoneal paraaortic dissection using the double bipolar method (DBM). Design We will show our double bipolar technique and give retrospective analysis of data. Setting Urban general hospital. Patients or Participants From December 26th 2018 to April 22nd 2019, 13 patients underwent extraperitoneal paraaortic dissection and 3 patients underwent both paraaortic and pelvic extraperitoneal dissection for stage I ovarian cancer (n=5) and endometrial cancer (n=8)- stage I-III. Interventions Informed consent was gained from all patients. Underlaparoscopic observation, we accessed the retroperitoneal space at the lower left flank extraperitoneally using an Endotip cannula. We expanded the peritoneal pocket to establish pneumo-retroperitoneum. Four extraperitoneal trocars along the left flank were placed. The DBM was originated by a robotic gastrointestinal surgeon, Prof Ichiro Uyama. This technique uses Robotic Maryland forceps for both cutting and coagulation. The cutting device is set with a special energy platform at macromode 60W. The lightning strike cutting mechanism is more precise than other instrumentation such as monopolar scissors and causes minimal thermal spread to adjacent organs. Measurements and Main Results The median number of retrieved lymph nodes in the paraaortic dissection was 32, in the pelvic dissection- 27. The estimated blood loss in the paraaortic dissection was almost 0ml, and 75ml in the pelvic. The median operating time was 147mins for the paraaortic dissection and 50mins for the pelvic dissection. No patients who underwent these interventions suffered organ injury or required a blood transfusion. Conclusion Extraperitoneal approach has the advantage of being a no-bowel operative field. The DBM makes it possible to perform accurate, bloodless dissection making it applicable to extended retroperitoneal dissection. The combination of this approach and technique can potentially be applied to total retroperitoneal dissection including para-aortic and pelvic lymphadenectomy cases.

Robotic Radical Trachelectomy Using the Double Bipolar Method- Aiming for a Bloodless Operative Field

Study ObjectiveTo report the application of the double bipolar technique in a patient with 1b1 cervical cancer who wished to preserve her fertility potential.DesignAfter experiencing 105 cases of laparoscopic and robotic radical trachelectomy with a 5 year survival rate of 98% and the birth of 29 babies from 51 of these patients who attempted pregnancy, we introduced the double bipolar method to overcome technical difficulties of the procedure due to the necessity for precise dissection and reconstruction in the deep pelvis. We will show our operative techniques, such as nerve sparing radical trachelectomy and retroperitoneal lymphadenectomy for early invasive cervical cancer in a bloodless operative field.SettingUrban general hospital.Patients or ParticipantsRobotic radical trachelectomy using the double bipolar method was performed in three patients with 1b1 cervical cancer.InterventionsAfter Robotic radical trachelectomy using monopolar scissors in 30 cases of stage Ib1 cervical cancer, we considered techniques for a more bloodless operative field. The double bipolar method (DBM) was originated by a robotic gastrointestinal surgeon, Prof Ichiro Uyama. Using robotic Maryland forceps as a cutting device allows for pinpoint accuracy that cannot be found in other instruments. It is important for bladder and ureteral dissection and exposure of vessels. Cuts are made at a very limited point by a lightning strike mechanism, meaning there is minimal thermal spread to adjacent organs.Measurements and Main ResultsBlood loss was 250ml in the cases presented. In surgeries not using the DBM(n=34), the blood loss ranged from 350ml(100-1200ml). While there is no supporting data, the dissection of the ureter was very smooth.ConclusionA bloodless operative field allows for accurate dissection and can prevent intraoperative injuries. The double bipolar method is able to provide precision cutting and limit thermal spread to adjacent tissue, reducing injury and allowing for a clear operative field.

The synchrotron maser emission from relativistic magnetized shocks: dependence on the pre-shock temperature

ABSTRACT Electromagnetic precursor waves generated by the synchrotron maser instability at relativistic magnetized shocks have been recently invoked to explain the coherent radio emission of fast radio bursts. By means of 2D particle-in-cell simulations, we explore the properties of the precursor waves in relativistic electron–positron perpendicular shocks as a function of the pre-shock magnetization σ ≳ 1 (i.e. the ratio of incoming Poynting flux to particle energy flux) and thermal spread Δγ ≡ kT/mc2 = 10−5−10−1. We measure the fraction fξ of total incoming energy that is converted into precursor waves, as computed in the post-shock frame. At fixed magnetization, we find that fξ is nearly independent of temperature as long as Δγ ≲ 10−1.5 (with only a modest decrease of a factor of 3 from Δγ = 10−5 to Δγ = 10−1.5), but it drops by nearly two orders of magnitude for Δγ ≳ 10−1. At fixed temperature, the scaling with magnetization $f_\xi \sim 10^{-3}\, \sigma ^{-1}$ is consistent with our earlier 1D results. For our reference σ = 1, the power spectrum of precursor waves is relatively broad (fractional width ∼1 − 3) for cold temperatures, whereas it shows pronounced line-like features with fractional width ∼0.2 for 10−3 ≲ Δγ ≲ 10−1.5. For σ ≳ 1, the precursor waves are beamed within an angle ≃σ−1/2 from the shock normal (as measured in the post-shock frame), as required so they can outrun the shock. Our results can provide physically grounded inputs for FRB emission models based on maser emission from relativistic shocks.

Ovarian responsiveness in assisted reproductive technology after CO2 fiber laser vaporization for endometrioma treatment: preliminary data.

Data about endometrioma ablation using energies with little thermal spread reported good results in terms of ovarian reserve and postoperative pregnancy rates. The aim of the present study was to assess the impact of one step CO<inf>2</inf> fiber laser vaporization for endometrioma on subsequent controlled ovarian stimulation. This prospective observational cohort study included a consecutive series of infertile patients who have undergone CO<inf>2</inf> fibre laser vaporization for endometrioma treatment. The primary endpoint was to assess the number of follicles per ovary growing during controlled ovarian stimulation. The secondary endpoints included the number of oocytes retrieved, the total number of embryos obtained and the cumulative clinical pregnancy rate per patient treated. Twenty-six patients underwent assisted reproductive technology after surgery for endometriosis-related infertility. In unilateral operated ovaries at the end of controlled ovarian stimulation no significant differences emerged from comparison of total recruited follicles in the operated ovary and in the contralateral ovary (P=0.55). If considering only bilateral endometriomas, the number of recruited follicles at the end of controlled ovarian stimulation was similar in both operated ovaries (P=0.79). The number of cumulative clinical pregnancies was 15 (57.7%; 95% CI: 38.5-76.9%). When comparing women aged ≤35 years to those aged >35 years, controlled ovarian stimulation outcomes were significantly higher in the younger patients. Age at the time of assisted reproductive technology was the only independent predictor for follicular growth during ovarian hyperstimulation (95% CI: -1.27 to -0.116, P=0.027). CO2 laser-treated endometrioma is associated with favorable reproductive assisted reproductive technology outcomes.

Vessel-Sealing Capability of Novel Microwave Sealer: Experimental Study in Animal Models.

Background. Ultrasonically activated dissectors (UADs) and radiofrequency-based devices have been considered excellent surgical devices because of their reliability and flexibility. Meanwhile, microwave-based devices have demonstrated potential with their unique heating mechanism. This study aims to compare the sealing function of a newly invented forceps-like microwave sealer (MS) with that of currently available UADs. Materials and Methods. MS and 2 examples of UADs (Harmonic Focus+ [HF+] and Sonicision [SNC]) were employed to perform mesenterectomies (in vivo) and sealing sizable vessels (ex vivo). Vessel diameter, seal time, burst pressure (BP), sealing completion, and instrument sticking were recorded. The samples underwent histological investigation for thermal damage evaluation. Results. During mesenterectomies, MS required 3seconds and 30W to secure a complete seal. The BP achieved by the MS seal was higher than that of HF+ and SNC on arteries (851 ± 203.7 vs 682.4 ± 287.3, P < .05; vs 833.1 ± 251.2mmHg, P = .4523, respectively) but was not statistically different on veins (324.9 ± 203.5 vs 460.1 ± 320.3 vs 508.3 ± 350.7mmHg, P = .215). In all trials, MS caused less sticking but exhibited similar heat-induced alterations to UADs. MS's thermal spread was not statistically more extended than that of UADs on either arteries or veins. Conclusions. MS was capable of not only sealing tiny vessels but also achieving high-pressure endurance on sizable vessels. Its forceful grasping and synchronous heating process helped create solid stumps with an acceptable thermal spread.

Thermal effects of monopolar electrosurgery detected by real-time infrared thermography: an experimental appendectomy study

BackgroundMonopolar energy (ME) is routinely used in appendectomy. This study aimed to investigate the degree of lateral thermal spread generated by ME and to evaluate the thermal injury sustained by the close-lying tissues.MethodsAppendectomy with a monopolar Maryland dissector was performed in 8 rabbits (at 30 and 60 W power settings). A high-resolution infrared camera was used to record tissue heating during the intervention. After autopsy macroscopic changes were evaluated and tissue samples were subjected to myeloperoxidase (MPO) assay and histological examination.ResultsNo significant differences in the extent of thermal spread, MPO activity and histological signs of inflammation were observed between groups. Regardless of the power settings, the heat spread exceeded 2 cm laterally along the mesoappendix when application time exceeded 3 s. The spread of heat through tubular structures in both groups caused a significant temperature rise in the nearby intestinal loop, resulting in perforation (n = 3) and necrosis (n = 1).ConclusionsApplication time is critical in thermal spread during appendectomy aided by ME. Tubular anatomic structures can enhance thermal injury on distant tissues. The observed effects of ME bear clinical relevance that need further investigation.