Direct Thermal Injury Research Articles

Comparative evaluation of efficiency of burn wound healing with derma-based hydrogel: a preclinical experimental study

Background. Burn wound healing is recognized as a complex process involving synergetic interactions between different cells, cytokines and growth factors. The adverse interactions can underlie chronicization of the process. Accordingly, the paper presents a relevant study into mechanisms of natural wound dressings, capable of influencing the processes of inflammation, angiogenesis, and skin resurfacing.Objective. To carry out a comparative evaluation of efficiency of burn wound healing with derma-based hydrogel according to the dynamics of proand anti-inflammatory factors.Methods. Development of a hydrogel material involved dermis samples of Landrace breed of pig, subjected to partial alkaline hydrolysis. In order to carry out a comparative evaluation of burn wound healing efficiency, the authors simulated direct thermal injury in three groups of sphinx (hairless) rats: group 1 (control group) — rats without treatment (n = 20), group 2 (comparison group) — rats treated with Levomekol ointment (n = 20), and group 3 (experimental group) — rats treated with hydrogel material (n = 20). Before and after injuring on days 1, 3, 7, 14, the content of cytokines interleukin-1β, interleukin-4, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor-α by enzyme immunoassay. The wound samples were explanted for histological examination on days 3, 7 and 14 after the beginning of the experiment. Statistical processing of the obtained results on DNA content in hydrogel, cytokine content in serum and morphometric data was performed using GraphPadPrism 6.04, Microsoft Excel 2016 (Microsoft, USA).Results. When determining the content dynamics of nonspecific markers of inflammation, an increase in the concentrations of interleukin-1β and tumor necrosis factor-α on day 1 after the hydrogel application was recorded, as well as an increase in interleukin-6 on days 3 and 7, while the concentrations of interleukin-8 did not change significantly throughout the experiment. Thus, dermal components are indicated to participate in the inhibition of acute-phase immune reactions. With regard to anti-inflammatory factors, the study revealed a decrease in the concentration of interleukin-10 on days 1 and 7, an increase in interleukin-4 on day 3 as compared to the control group, thereby indicating a pronounced anti-inflammatory effect and prolonged action of the hydrogel.Conclusion. Comparative analysis of the pro-inflammatory cytokines levels (interleukin-1β, interleukin-8) showed pronounced anti-inflammatory effects of the derma-based hydrogel material. Introduction of exogenous biological components of the extracellular matrix (collagen and its hydrolysates) had a significant influence on the regulation of anti-inflammatory cytokines synthesis, presumably contributing to faster successful epithelization and wound healing.

Bipolar radiofrequency ablation lesion areas and confluence: An exvivo study and technical report.

Radiofrequency ablation (RFA) has been used for nearly 100 years, treating an array of medical conditions including chronic pain. Radiofrequency (RF) energy depolarizes and repolarizes tissues adjacent to a probe producing heat and causing direct thermal injury. When positioned adjacent to neural structures, it leads to neural tissue injury and cell death interrupting pain signaling with the ultimate goal of providing lasting pain relief. Today, RFA is commonly used to treat cervical, thoracic, and lumbar zygapophyseal joints, sacroiliac joint, and more recently large peripheral joint-mediated pain. There are several applications of RFA systems, including bipolar, conventional thermal, cooled, protruding, and pulsed. As yet, no study has determined the best technical practice for bipolar RFA. This exvivo study examines RFA lesion midpoint (LMP) area and lesion confluence comparing three different commonly used gauge (g) probes (18-g, 20-g, and 22-g) with 10-mm active tips at various interprobe distances (IPD) to guide best technical practices for its clinical application. Bipolar RFA lesions were generated in preservative-free chicken breast specimens using three different gauge probes (18-g, 20-g, and 22-g) with 10-mm active tips at various IPD (6, 8, 10, 12, 14, 16, and 18 mm). RF was applied for 105 s (15-s ramp time) at 80°C for each lesion at both room and human physiological temperature. The specimen tissues were dissected through the lesion to obtain a length, width, and depth, which were used to calculate the LMP area (mm2 ). The LMP areas of each thermal ablation were investigated using visualization and descriptive analysis. The Kruskal-Wallis test was performed to compare LMP areas between the two temperature groups and the three different gauge probe subgroups at the various IPDs. Of the 36 RF lesions (14: 18-g, 12: 20-g, and 10: 22-g) performed, 24 demonstrated lesion confluence. The average time to reach 80°C was 16-17 s; therefore, the average time of RF-energy delivery (at goal temperature) was 88-89 s despite varying needle size or IPD. Comparing the 25 and 37°C groups, 18-g probes produced mean LMP areas of 73.7 and 79.2 mm2 , respectively; 20-g probes produced mean LMP areas of 66 and 66.8 mm2 , respectively; 22-g probes produced mean LMP areas of 56.6 and 59.7 mm2 , respectively. There was no statistical evidence to state a difference regarding LMP area between temperature groups; however, the 18-g probes produced consistently larger LMP areas in the 37°C compared to 25°C specimen groups at each IPD. Lesion confluence was lost for 18-g, 20-g, and 22-g probes at IPD of 14, 12, and 10 mm, respectively, in both 25 and 37°C groups. LMP area was similar between 6 and 8 mm IPD in all of the three-gauge groups; however, there was a significant drop in LMP area from 8 mm IPD to 10 mm and greater. The 18-g, 20-g, and 22-g probes all demonstrated a sharp decline in LMP area when increasing the IPD from 8 to 10 mm. This exvivo technical study evaluated bipolar RFA LMP areas and lesion confluence, and determined the recommended IPD of 18-g, 20-g, and 22-g probes to be less than 12, 10, and 8 mm, respectively, for best clinical practice. Placing bipolar probes at an IPD greater than 14, 12, and 10 mm, respectively, risks the loss of lesion confluence and failure to produce a clinically significant treatment response due to lack of nerve capture. In clinical practice, the use of injectate may produce larger lesions than demonstrated in this study. Additionally, invivo factors may impact ablation zone size and ablation patterns. As there are a paucity of studies comparing various RFA applications and conventional RFA needles are least expensive, it is possible that bipolar conventional RFA is more cost-effective than other techniques.

Iatrogenic Nerve Injuries of the Upper Extremity: A Critical Analysis Review.

Iatrogenic nerve injuries may occur after any intervention of the upper extremity. Causes of iatrogenic nerve lesions include direct sharp or thermal injury, retraction, compression from implants or compartment syndrome, injection, patient positioning, radiation, and cast/splint application, among others. Optimal treatment of iatrogenic peripheral nerve lesions relies on early and accurate diagnosis. Advanced imaging modalities (e.g., ultrasound and magnetic resonance imaging) and electrodiagnostic studies aid and assist in preoperative planning. Optimal treatment of iatrogenic injuries is situation-dependent and depends on the feasibility of direct repair, grafting, and functional transfers.

Acute Hemoptysis Following Cryoballoon Pulmonary Vein Isolation

This study sought to assess the incidence, procedural characteristics, contributing factors, and clinical outcome of cryoballoon-based pulmonary vein isolation (CB-PVI)-related hemoptysis in a multicenter study. Hemoptysis has been described as a rare complication of CB-PVI. However, the precise mechanism and the etiology of this complication are poorly characterized. Consecutive patients undergoing CB-PVI for paroxysmal or persistent atrial fibrillation at 4 German hospitals were included in this observational analysis. A total of 4,331 CB-PVI procedures were performed between 2006 and 2019. Fifteen patients (9 men, mean age 68.1 ± 9.8 years) developed acute hemoptysis during or within 24h after CB-PVI, resulting in a hemoptysis frequency of 0.35%. Hemoptysis occurred in 6 of 720 procedures using the first-generation CB (0.83%) and in 9 of 3,611 procedures using the second-, third-, or fourth-generation CB (0.25%) (p=0.015). Bronchoscopy was performed in 8 patients and showed bleeding exclusively due to mucosal injury or due to a coagulum at a bronchus adjacent to the ablation site. Hemoptysis resolved spontaneously without any long-term sequelae in all patients, except for a 92-year-old patient who died 13days after CB-PVI due to pneumonia. No specific endobronchial treatment was necessary. Acute hemoptysis after CB-PVI is a rare but potentially life-threatening complication that is usually self-limiting. Direct thermal injury of bronchi adjacent to a pulmonary vein seems to be the most likely mechanism.

A Case of Direct Thermal Esophageal Injury Caused by Hot Noodle-Soup

Esophageal thermal injury can develop due to the ingestion of hot food and liquids [1], left atrial catheter ablation [2], caustic ingestion, or by smoking freebase cocaine [3]. Since direct thermal injury is not a known cause of esophageal ulcer, these rare cases can be easily overlooked by physicians [4]. We herein introduce the case of a woman whom we suspected to experience thermal injury-induced esophageal ulcers (Table 1).

P1917Can cryoballoon ablation produce alterations in cardiac and extra-cardiac autonomic nervous system in patients with atrial fibrillation?

Abstract Background Cryoballoon ablation (CBA) during pulmonary vein isolation (PVI) for atrial fibrillation (AF) can cause direct thermal injury to structures adjacent to the left atrium, including the periatrial ganglionated plexi (GP). In contrast, it has not been clarified whether cardiac autonomic nervous system (CANS) modification by CBA could indirectly affect extra-CANS. Purpose This study was aimed to investigate the impact of CBA on extra-CANS as well as CANS in AF patients. Methods Ninety-three Consecutive patients who underwent initial CBA in our institute were enrolled. Among them, 64 subjects (age 67±9 years; male gender 52%; CHADS2 score 1.2±1.0; diabetes mellitus 16%; β-blocker therapy 23%) had paroxysmal AF (G-P) and 29 (age 66±7 years; male gender 90%; CHADS2 score 1.3±1.0; diabetes mellitus 24%; β-blocker therapy 34%) had sustained AF (G-S). In G-P, resting sinus heart rate (R-HR) and coefficient of variation of the R-R intervals (CVR-R) during sinus rhythm were measured in resting 12-lead electrocardiogram before and after CBA as an index of CANS. Decrease in CVR-R after PVI reflects the vagal nerve injury by the procedure. Pupil movement reflects the autonomic nervous function. In both groups, pupillary light reflex, as an indicator of extra-CANS activity, was measured by infrared videopupillography (Iriscorder® Dual C10641, Hamamatsu Photonics, Hamamatsu, Japan) before and after CBA. Velocity of dilatation (VD) is related to sympathetic function, and velocity of contraction (VC) is associated with the balance between sympathetic and vagal tone. All CBA were treated with second generation 28mm cryoballoons (CB). CB temperature was down to a minimum of −60°C and target application time was 180 seconds. Results Complete PVI was achieved in all patients, in which touch-up radiofrequency ablation for the PVI was required in 4 cases of G-S. In G-P, R-HR significantly increased (59.2±9.2bpm to 72.5±8.3bpm, p<0.01) and CVR-R significantly decreased (2.32±1.1% to 1.61±0.61%, p<0.01) after CBA, while VC and VD did not significantly change (3.83±1.03mm2/sec to 3.64±0.96mm2/sec and 1.83±0.62mm2/sec to 1.86±0.84mm2/sec, respectively). In G-S, there were not significant changes between before and after CBA in VC and VD (3.77±0.80mm2/sec to 3.71±0.99mm2/sec and 1.81±0.49mm2/sec to 1.80±0.59mm2/sec, respectively). There were no significant differences between two groups in VC and VD before the procedure. Conclusion These results suggest that CBA seems to result in local parasympathetic denervation due to damage of adjacent structures including ganglionated plexi while the alteration of CANS by CBA does not seem to efferently affect extra-CANS.

Early and Delayed Alteration of Atrial Electrograms Around Single Radiofrequency Ablation Lesion.

Purpose: The acute effect of radiofrequency (RF) ablation includes local necrosis and oedema. We investigated the spatiotemporal change of atrial electrograms in the area surrounding the site of single standardized pulse of RF energy.Methods: The study enrolled 12 patients (45–67 years, 10 males) with paroxysmal atrial fibrillation (AF) undergoing ablation procedure with irrigated-tip ablation catheter and 3D navigation. The high-density mapping/remapping (129 ± 63 points) within the circular area with radius of ~10 mm, centered at the pre-specified posterior left pulmonary vein antrum ablation site was performed at baseline, immediately after single RF energy delivery (25 W, 30 s, 20 ml/min) and after 30 min waiting period. Bipolar voltages of atrial electrograms (A-EGM-biV) were averaged within the central and 12 adjacent left atrium segments and their relative change was studied.Results: After the ablation, overall A-EGM-biV within the mapping zone (3.51 ± 1.89 mV at baseline) reduced to 2.83 ± 1.77 mV (immediately) and to 2.68 ± 1.58 mV (after 30 min waiting period). In per-segment pair-wise comparison, we observed highly significant change in A-EGM-biV that extended up to the distance of 8.8 mm from the lesion core. The maximum early A-EGM-biV attenuation by 39–49% (P < 0.001) was registered in segments adjacent to pulmonary vein ostia. The subsequent (delayed) A-EGM-biV reduction by 17–24% (P < 0.05) was observed in opposite direction from the lesion center.Conclusions: Significant alteration of atrial electrograms was detectable rather distant from the central lesion. Spatiotemporal development of ablation lesion was eccentric/asymmetric. While acute A-EGM-biV reduction can be attributed predominantly to direct thermal injury, delayed effects are probably due to oedema progression.

Variable heat shock response model for medical laser procedures

According to the standard Arrhenius relation, tissue damage is linearly dependent on the duration of exposure to elevated temperatures and exponentially dependent on the temperature itself. However, recently published measurements of damage threshold temperatures at extremely short exposure times (commonly present during laser treatments) exhibit a shift to temperatures that are higher than what would normally be expected from a single-process Arrhenius model. A novel variable heat shock (VHS) response model was developed that takes into account the observed deviation from the single-process Arrhenius relation, by assuming that the cell viability can be described as the combined effect of two biochemical processes that dominate cell survival characteristics at very short and very long exposure times. The potential implications of the VHS model are explored theoretically through an example of non-ablative laser resurfacing. The VHS model shows that under the appropriate conditions, very high temperature heat shocks can be generated within the superficial epithelium tissue layer without causing irreversible tissue damage. A mechanism of action for tissue regeneration by means of non-ablative resurfacing with the Er:YAG laser is proposed, which involves indirect triggering of tissue regeneration through intense heat shock to the epithelia, in addition to the tissue regeneration mechanism by means of direct thermal injury to deeper lying connective tissues.

Electrophysiology of Cranial Nerve Testing: Auditory Nerve.

The electrocochleogram and brainstem auditory evoked potentials (BAEPs) are electrophysiologic signals used to assess the auditory nerve. The electrocohleogram includes the cochlear microphonic, the cochlear summating potential, and the eighth nerve compound action potential. It is used predominantly for hearing assessment and for diagnosis of Ménière disease and auditory neuropathy. Brainstem auditory evoked potentials are used for hearing assessment, diagnosis of dysfunction within the cochlea, the auditory nerve, and the brainstem auditory pathways up to the level of the mesencephalon, and intraoperative monitoring of these structures. The earliest BAEP component, wave I, and the eighth nerve compound action potential reflect the same process-the initial depolarization in the distal auditory nerve. Brainstem auditory evoked potential wave II receives contributions from the region of the cochlear nucleus and from the second depolarization in the distal auditory nerve. Wave III and later components are entirely generated rostral to the auditory nerve. Interpretation of BAEP studies is based on waves I, III, and V; auditory nerve dysfunction is manifested as prolongation of the I-III interpeak interval or absence of waves III and V. Eighth nerve tumors can cause a variety of BAEP abnormalities depending on which structures they affect. Adverse intraoperative BAEP changes can have many etiologies, including direct mechanical or thermal injury of tissue, ischemia (including cochlear ischemia or infarction due to compromise of the internal auditory artery), eighth nerve stretch, systemic or localized hypothermia, and artifactual BAEP changes due to technical factors.

045 HEAT STROKE WITH ACUTE KIDNEY INJURY AND RHABDOMYOLYSIS: A CASE REPORT

Category: Epidemiology and Outcomes from AKI Presenter: Dr AISYA FATHANAH BAHARI Keywords: heat stroke, rhabdomyolysis, acute kidney injury Heatstroke is a medical emergency and severe presentations may present with multiorgan failure. We report a case of with multiple organ dysfunction secondary to heat stroke. A 21-year-old male was brought to the emergency department of the local district hospital after he became unconscious while participating in a multisport event. On arrival, core temperature was 41 degrees Celsius with a Glasgow Coma Scale of 8/15. He was nursed in the Intensive Care Unit (ICU) at a tertiary hospital. Initial cooling and rehydration therapy was started immediately, upon his presentation to a district hospital. He developed seizures and needed ventilator support. A sedative was administered and tracheal intubation was performed. His CT Scan of his Brain was essentially normal. He developed worsening organ dysfunction with severe rhabdomyolysis. He had Acute Kidney Injury Network (AKIN) Stage 3 despite aggressive initial therapy and needed support with Continuous Veno-Veno Hemodialysis (CVVH) on Day 4 of admission. His Creatinine Kinase levels peaked at 31,222 U/L and alaninine transferase (ALT) was at 2782U/L. His CVVH continued for 57 hours, was subsequently able to tolerate intermittent hemodialysis. He was weaned off from dialysis support at Day 13 of admission as he had developed full renal recovery. Patient gradually improved and was extubated on the 24th day of admission. He developed hospital-acquired pneumonia and catheter-related infections; which were addressed with appropriate antibiotic therapy. Upon discharge at Day 35, patient was well without any neurological sequele. His serum creatinine on discharge was 82 umol/L. Rhabdomyolysis and acute kidney injury (AKI) is a common presentation in severe heatstroke. Acute kidney injury due to heatstroke was worsened by concomitant rhabdomyolysis and systemic inflammatory response syndrome. Etiology is multifactorial, includes direct thermal injury, rhamdomyolysis, disseminated intravascular complications and renal hypo-perfusion due to depleted volume. Severe heatstroke can cause profound AKI. Physicians should be able to identify and treat heatstroke to avoid complications and reduce mortality and morbidity.

Solar retinopathy following cannabis consumption

Solar retinopathy is a photochemical toxicity to the retina induced by light rather than a direct thermal injury. It is caused mainly by viewing a solar eclipse, excessive sun gazing or welding exp...

Complication avoidance in laser interstitial thermal therapy: lessons learned.

OBJECTIVE Complications of laser interstitial thermal therapy (LITT) are underreported. The authors discuss how they have modified their technique in the context of technical and treatment-related adverse events. METHODS The Medtronic Visualase system was used in 49 procedures in 46 patients. Between 1 and 3 cooling catheters/laser fiber assemblies were placed, for a total of 62 implanted devices. Devices were placed using frameless stereotaxy (n = 3), frameless stereotaxy with intraoperative MRI (iMRI) (n = 9), iMRI under direct vision (n = 2), MRI alone (n = 1), or frame-based (n = 47) techniques. LITT was performed while monitoring MRI thermometry. Indications included brain tumors (n = 12), radiation necrosis (n = 2), filum terminale ependymoma (n = 1), mesial temporal lobe epilepsy (n = 21), corpus callosotomy for bifrontal epilepsy (n = 3), cavernoma (n = 1), and hypothalamic hamartomas (n = 6). RESULTS Some form of adverse event occurred in 11 (22.4%) of 49 procedures. These included 4 catheter malpositions, 3 intracranial hemorrhages, 3 cases of neurological deficit related to thermal injury, and 1 technical malfunction resulting in an aborted procedure. Of these, direct thermal injury was the only cause of prolonged neurological morbidity and occurred in 3 of 49 procedures. Use of frameless stereotaxy and increased numbers of devices were associated with significantly increased complication rates (p < 0.05). A number of procedural modifications were made to avoid complications, including the use of 1) frame-based catheter placement, a 1.8-mm alignment rod to create a track and titanium skull anchors for long trajectories to improve accuracy; 2) a narrow-gauge instrument for dural puncture and coregistration of contrast MRI with CT angiography to reduce intracranial hemorrhage; 3) general endotracheal anesthesia for posterior-placed skull anchors to reduce the likelihood of damage to the cooling catheter; 4) use of as few probes as possible to reduce complications overall; and 5) dose modification of thermal treatment and use of short (3-mm) diffusing tips to limit treatment when structures to be spared do not have intervening CSF spaces to act as heat sinks. CONCLUSIONS Laser ablation treatment may be used for a variety of neurosurgical procedures for patients with tumors and epilepsy. While catheter placement and thermal treatment may be associated with a range of suboptimal operative and postoperative courses, permanent neurological morbidity is less common. The authors' institutional experience illustrates a number of measures that may be taken to improve outcomes using this important new tool in the neurosurgical arsenal.

Spatial relationship of coronary sinus-great cardiac vein to mitral valve annulus and left circumflex coronary artery: implications for cardiovascular interventional procedures.

The spatial relationship of the coronary sinus-great cardiac vein (CS-GCV) to free posterior portion of the mitral valve annulus (MVA) and left circumflex coronary artery (LCx) has gained importance with the advent of cardiovascular interventional procedures such as percutaneous transvenous mitral annuloplasty (PTMA) and mitral isthmus (MI) ablation. In 50 normal (nondilated cardiomyopathy, or non-DCM) and 20 dilated cardiomyopathy (DCM) cadaveric hearts, the diameter and distance from the MVA of CS-GCV and its spatial relationship to LCx along the free posterior portion of the MVA were studied. The diameter of the CS-GCV increased from the beginning to termination in both non-DCM and DCM cases. The CS-GCV was located farthest from the MVA in the vertical plane in the middle of its course and in the horizontal plane at its beginning. The LCx was located above the CS-GCV in direct contact with the epicardial aspect of MI in 12% non-DCM and 15% DCM cases and was wedged between the CS-GCV and MI in 20% non-DCM and 15% DCM cases. Knowledge of the separation between the CS-GCV and MVA in the horizontal and vertical planes could help in selecting suitable candidates and the preprocedural prediction of success of PTMA. Awareness of the spatial relationship of LCx with CS-GCV in MI would help to reduce the risk of incomplete MI block due to a heat sink effect or damage to the LCx by direct thermal injury during MI ablation.

Beyond the fire: smoke inhalational injury as a respiratory concern

In fire events, smoke inhalation is the leading cause of death in survivors of the primary fire mortality. Direct upper airway thermal injury is only one of the contributing mechanisms. Others may be related to the nature of the combusted (or incomplete combusted) materials in the scene; eg.; aldehydes, sulphur oxides and nitrogen as a cotton combustion products, while burning polyvinylchloride (PVC's) releases carbon monoxide (CO) and hydrochloric acid, among more than 75 potentially toxic compounds including cyanide. Hot carbonated gaseous materials and soot may lead to supraglottic, glottic, or infraglottic airway obstruction however; significant hypoxemia is not the typical sign in acute cases without aspiration or parenchymal lung injuries. Injury may not manifest until after 48 hours.

Cap-assisted argon plasma coagulation

Cap-assisted argon plasma coagulation is carried out with a clear cap over the tip of the endoscope. The catheter is then positioned within the cap in such a manner that the tip of the catheter is kept at a reproducible distance from the mucosa (Fig. 1). This obviates the possibility of direct mucosal contact and the resulting direct thermal injury. It also allows for a very precise delivery of current to the target tissues by maintaining the position of the endoscope tip and catheter tip relative to the intended treatment area, maintaining luminal patency, and controlling the local gas dynamics of the argon. This technique does not appear to be widely used and has not been described in the medical literature, to our knowledge, but we suspect that some endoscopists may find it helpful. Video 1 (available online at www. giejournal.org) demonstrates this technique by use of a single-use, soft, straight cap (Olympus, Tokyo, Japan) to ablate radiation proctopathy in a symptomatic 68year-old man.

Trigemino‐Cardiac Reflex as Lethal Mechanism in a Suicidal Fire Death Case

In the vast majority of immediate fire deaths, the mechanism of death is inhalation of toxic gases (especially carbon monoxide), direct thermal injury, or neurogenic shock due to the redistribution of the body's blood volume produced by surface heat on the skin. We present a suicidal case that is unusual because the mechanism of immediate fire death could arguably be explained in terms of a primitive autonomic reflex/the trigemino-cardiac reflex. Although this reflex is well known to surgeons and anesthetists, with possible lethal consequences in the course of invasive surgical procedures on the head and neck region, it is much less familiar to forensic pathologists.

Slow pathway ablation for typical atrioventricular nodal re-entrant tachycardia significantly alters the autonomic modulation of atrioventricular conduction

Atrioventricular (AV) conduction turbulence, biphasic dromotropic response of AV node to single ventricular premature contraction (VPC), consists of early shortening and later prolongation of AV conduction intervals due to the direct electrophysiological mechanisms and perturbation in autonomic modulation. We investigated the acute effect of radiofrequency catheter ablation of slow pathway on AV turbulence. The electrophysiological study was performed in 18 patients (7 men, mean age 49±15years) undergoing catheter ablation for AV nodal reentrant tachycardia. The stimulation protocol consisting of series of isolated VPC (coupling interval of 273±23ms) delivered from right ventricle apex during constant atrial pacing at 100bpm was performed immediately prior to and 8±4min after successful slow-pathway ablation. Averaged post-VPCs profiles of AV conduction intervals were analyzed by purpose-written software. The descriptors of AV turbulence, turbulence onset (TOAV), turbulence slope (TSAV), and AV recovery (R AV) were assessed. Slow-pathway ablation suppressed the AV nodal responsiveness to VPC as evidenced by significant reduction of AV turbulence indices: TOAV: -6.4±7.5% vs. -4.3±6.1% (p<0.05); TSAV: 2.0±2.6ms/RRi vs. 1.0±0.7ms/RRi (p<0.05); and R AV: -13.8±7.3% vs. -6.5±12.7% (p<0.05). Slow-pathway ablation significantly attenuated both vagal and non-autonomic modulation of AV nodal conduction. This effect is likely due to direct thermal injury of AV node associated with the change of properties of AV nodal fast-pathway although specific alteration of peri-AV nodal ganglionated plexi or their neural inputs into the AV node cannot be excluded.

Laparoscopic Primary Colorrhaphy for Acute Iatrogenic Perforations during Colonoscopy

Purpose. We present our experience with laparoscopic colorrhaphy as definitive surgical modality for the management of colonoscopic perforations. Methods. Over a 17-month period, we assessed the outcomes of consecutive patients presenting with acute colonoscopic perforations. Patient characteristics and perioperative parameters were tabulated. Postoperative outcomes were evaluated within 30 days following discharge. Results. Five female patients with a mean age of 71.4 ± 9.7 years (range: 58–83), mean BMI of 26.4 ± 3.4 kg/m2 (range: 21.3–30.9), and median ASA score of 2 (range: 2-3) presented with acute colonoscopic perforations. All perforations were successfully managed through laparoscopic colorrhaphy within 24 hours of development. The perforations were secondary to direct trauma (n = 3) or thermal injury (n = 2) and were localized to the sigmoid (n = 4) or cecum (n = 1). None of the patients required surgical resection, diversion, or conversion to an open procedure. No intra- or postoperative complications were encountered. The mean length of hospital stay was 3.8 ± 0.8 days (range: 3–5). There were no readmissions or reoperations. Conclusion. Acute colonoscopic perforations can be safely managed via laparoscopic primary repair without requiring resection or diversion. Early recognition and intervention are essential for successful outcomes.

Complex anatomy surrounding the left atrial posterior wall: analysis with 3D computed tomography

Few studies have explored the topographic anatomy of the esophagus, posterior wall of the left atrium (LA), or fat pads using multidetector computed tomography (MDCT) to prevent the risk of esophageal injury during atrial fibrillation (AF) ablation. MDCT was performed in 110 consecutive patients with paroxysmal or persistent AF before the ablation procedure to understand the anatomic relationship of the esophagus. Two major types of esophagus routes were demonstrated. Leftward (type A) and rightward (type B) routes were found in 90 and 10% of the patients, respectively. A type A route had a larger mean size of the LA than type B. The fat pad was identifiable at the level of the inferior pulmonary vein in 91% of the patients without any predominance of either type. The thickness of the fat pad was thinner in the patients with a dilated LA (>42 mm) than in those with a normal LA size (≤42 mm) (p = 0.01). The results demonstrated that the majority of cases had a leftward route of the esophagus. There was a close association between the LA dilatation and fat pad thinning. With a dilated LA, the esophagus may become easily susceptible to direct thermal injury during AF ablation. Visualization of the anatomic relationship may contribute to the prevention of the potential risk of an esophageal injury.

Use of an Ultrasonic Bone Aspirator (Sonopet) for Anterior Clinoidectomy during Paraclinoid Cerebral Aneurysm Surgery

Introduction: The use of a high-speed power-drilling technique has been advocated for anterior clinoidectomy in prior publications on paraclinoid aneurysm surgery. Potential risks associated with it include exposure of the shaft of the drill to neurovascular structures and the risk for direct mechanical or thermal injury. The use of an ultrasonic bone aspirator (Sonopet) has recently been described. The potential advantage of this system is the lack of any mobile parts, decreasing the risks associated with power drills. We investigated its safety profile in anterior clinoidectomy during cerebrovascular surgery in our own series.