An Immunomodulatory Protein (Ling Zhi-8) from a Ganoderma lucidum

The purpose of this study was to investigate the effect of an immunomodulatory protein (Ling Zhi-8, LZ-8) on wound healing in rat liver tissues after monopolar electrosurgery. Animals were sacrificed for evaluations at 0, 3, 7, and 28 days postoperatively. It was found that the wound with the LZ-8 treatment significantly increases wound healing. Western blot analysis clearly indicated that the expression of NF-κB was decreased at 3, 7, and 28 days when liver tissues were treated with LZ-8. Moreover, caspase-3 activity of the liver tissue also significantly decreases at 7 and 28 days, respectively. DAPI staining and TUNEL assays revealed that only a minimal dispersion of NF-κB was found on the liver tissue treated with LZ-8 at day 7 as compared with day 3 and tissues without LZ-8 treatment. Similarly, apoptosis was decreased on liver tissues treated with LZ-8 at 7 days when compared to the control (monopolar electrosurgery) tissues. Therefore, the analytical results demonstrated that LZ-8 induced acceleration of wound healing in rat liver tissues after monopolar electrosurgery

Surgically generated aerosol and mitigation strategies: combined use of irrigation, respirators and suction massively reduces particulate matter aerosol

Background Aerosol is a health risk to theatre staff. This laboratory study quantifies the reduction in particulate matter aerosol concentrations produced by electrocautery and drilling when using mitigation strategies such as irrigation, respirator filtration and suction in a lab environment to prepare for future work under live OR conditions. Methods We combined one aerosol-generating procedure (monopolar cutting or coagulating diathermy or high-speed diamond- or steel-tipped drilling of cadaveric porcine tissue) with one or multiple mitigation strategies (instrument irrigation, plume suction and filtration using an FFP3 respirator filter) and using an optical particle counter to measure particulate matter aerosol size and concentrations. Results Significant aerosol concentrations were observed during all aerosol-generating procedures with concentrations exceeding 3 × 106 particles per 100 ml. Considerable reductions in concentrations were observed with mitigation. In drilling, suction, FFP3 filtration and wash alone respectively reduced aerosol by 19.3–31.6%, 65.1–70.8% and 97.2 to > 99.9%. The greatest reduction (97.38 to > 99.9%) was observed when combining irrigation and filtration. Coagulating diathermy reduced concentrations by 88.0–96.6% relative to cutting, but produced larger particles. Suction alone, and suction with filtration reduced aerosol concentration by 41.0–49.6% and 88.9–97.4% respectively. No tested mitigation strategies returned aerosol concentrations to baseline. Conclusion Aerosol concentrations are significantly reduced through the combined use of filtration, suction and irrigation. Further research is required to characterise aerosol concentrations in the live OR and to find acceptable exposure limits, and in their absence, to find methods to further reduce exposure to theatre staff

Adequacy of ovarian diathermy under ultrasound control: an experimental model

Background: To develop a minimally invasive ovarian cauterization technique under transvaginal ultrasound control and evaluate the safety and feasability of monopolar cauterization to cause ovarian injury using female cattle of reproductive age as an experimental model. Method: Experimental study in a university research center was performed. Eleven female bovines of reproductive age were submitted to monopolar transvaginal ovarian cauterization. The right ovary (RO) was punctured at four sites and 40 W was applied for 5 s at each point, resulting in a total of 800 J (Joules) of thermal energy. In the left ovary (LO), the procedure was similar, with the same time and 80 W, resulting in a thermal energy of 1600 J. Macroscopic and microscopic lesions were assessed. Results: Of 22 ovaries punctured, 20 were cauterized and exhibited macroscopic and typical microscopic lesions. No lesions could be found in the needle path. The measures of the areas of microscopic electrocautery lesions calculated estimating a cylindrical volume showed a median of 1.12% in the right ovary and 1.65% in the left ovary. When the estimate was calculated by spherical shape, the medians were 1.77% in the right ovary and 3.06% in the left ovary. There was a statistically significant difference in these two estimates (sphere, p = 0.008; cylinder, p = 0.021). Conclusion: The experimental animal model described for transvaginal ultrasound-guided ovarian needle cauterization seems to be feasible. The ovaries were successfully cauterized without injuries in needle path and more energy resulted in significantly more thermal lesion. The safety and effectiveness of this technique, theoretically less invasive than current ovarian drilling methods, could be tested in anovulatory women with PCOS

Development and evaluation of a titanium-based planar ultrasonic scalpel for precision surgery.

This paper introduces a titanium-based planar ultrasonic microscalpel. The concept of silicon-based planar ultrasonic transducers has already been proven, but they are not yet suitable for clinical use due to material failure. The main objective of this work was to develop a smaller, lighter, and more cost-effective ultrasonic scalpel that could be used as an alternative or supplementary device to current surgical instruments. Various prototypes were fabricated and characterized, differing in bonding by three epoxy adhesives and two solder pastes as well as three variations in tip design. The instruments were designed to operate in the frequency range of commercial instruments and to generate a longitudinal displacement amplitude. The electro-mechanical characterization through impedance analysis and vibration measurements was complemented by an in vitro cutting trial and an acute in vivo animal experiment in comparison to commercial ultrasonic and electrosurgical devices. The operating frequency was around 40 kHz and 48 kHz depending on whether matched or unmatched operation was used. Unmatched operation turned out to be more suitable, achieving displacement amplitudes of 25.3 μm and associated velocity amplitudes of up to 7.9 m/s at an electrical power of 10.2 W. The cutting ability was demonstrated in vivo by successful dissection even under anticoagulation. The geometry of the instrument tip was found to have a major influence on cutting performance by affecting the resonance behaviour and tissue penetration

Development Of Ultrasonic Cautery System

The use of piezoelectric element as the primary ultrasonic transducer is prevalent in ultrasonic cautery system. Proper method to characterize an ultrasonic scalpel has become an important design process. In this study, an ultrasonic scalpel prototype was characterized using both finite element modelling and experimental procedures. FEM simulation software, Abaqus was utilized to investigate preloading effects, proper longitudinal mode shape, resonant frequency, and mechanical response due to harmonic excitation. Experimental modal and harmonic analyses were used for experimental validation. The simulated results were in accordance to the theoretical calculation for the preloading effects, where sufficient compressive stress of 27 MPa was imposed onto the piezoceramic rings and an internal stress developed within the bolt approached 190 MPa. Modal analysis detected a resonant frequency at 47740 Hz with a dominant longitudinal mode shape. For harmonic analysis, simulated result suggested 76.85 microns of mechanical displacement amplitude while experimental procedure measured 54 microns. The results concluded that the ultrasonic scalpel was successfully characterized

Fracture Toughness of a Hyperelastic Material During Surgical Cutting

Despite being one of the most important organs of vertebrates, the material properties of skin are also one of the most poorly understood. In the field of designing medical devices and surgical tools there are significant advantages to having a model that describes the interaction of forces between a blade tip and skin during surgical cutting. In general, skin can best be described as a composite layer consisting of a viscoelastic dermis with interwoven collagen and elastin fibers beneath a superficial epidermis. The purpose of this research is to study the fracture toughness of porcine skin during practical cutting applications, the behavior of skin under quasistatic loads, and viscoelastic behavior of skin during stress relaxation. To fully describe the mechanics of skin in this model tensile test are conducted to determine the material properties of skin. The fracture toughness of the material is calculated by measuring the energy release rate of the material during required during cutting with Number 11 scalpel blade with a tip radius of 12 [micro]m . These results are then compared to a finite element analysis with a debonding interface and a Mooney-Rivlin hyperelastic material model with viscoelastic relaxation in an effort to predict the loads required by tools during surgical applications. The main outcome of this research is the development of a testing protocol and material model of skin that can be used in finite element simulations of uniaxial loads and surgical cutting

Inferior Turbinate Surgery in Sleep-Disordered Breathing Patients with Nasal Obstruction: Principles and Various Techniques

Sleep-disordered breathing (SDB) is characterized by the intermittent narrowing or collapse of the upper airway, including the nasal cavity, pharynx, and larynx during sleep. Nasal obstruction is one of the most frequent presenting symptoms in SDB patients, and therefore, medical treatments such as saline nasal irrigation, antihistamine, and topical nasal spray are the first recommendation. If the issue is not resolved, surgical treatments for nasal congestion are helpful in order to alleviate nasal obstruction, reduce snoring, and improve positive airway pressure compliance. Inferior turbinate surgery is one of the most commonly performed nasal surgeries (e.g., endoscopic sinus surgery, septoplasty, etc) used to improve nasal obstruction. There are various inferior turbinate surgical methods including electrocautery, laser-assisted turbinoplasty, radiofrequency-assisted turbinoplasty, outfracture, submucous turbinoplasty, partial turbinectomy, and microdebrider-assisted turbinoplasty. Despite the development of these numerous approaches, no clear guidelines exist as yet to help determine the most appropriate modality for any individual patient. This is due to variation in pathophysiology and the degree and extent of the turbinate hypertrophy between patients. Consequently, a comprehensive understanding of these techniques, as well as the preservative concept of functional nasal physiology, is critically important for all surgeons. We propose that the ideal inferior turbinate surgery would meet the following criteria: 1) be less invasive, 2) incorporate remodeling rather than excessive resection, 3) entail a submucosal versus superficial mucosal technique, 4) represent an individually selected technique that is best suited to the patient, and 5) address long term considerations rather than acute symptomatic relief

CHARACTERIZATION OF SURGICAL PLUME AEROSOLS AND ASSESSMENT OF OCCUPATIONAL EXPOSURES AMONG OPERATING ROOM PERSONNEL

These studies were undertaken to increase the knowledge of characteristics of plume particles produced by surgical cutting and cauterizing instruments and to assess occupational exposure to these surgical plume particles. Surgical plume particle characteristics measured included particle size distribution and particle number, respirable mass, active surface area, and particle-bound polycyclic aromatic hydrocarbon (pPAH) concentrations. The four surgical instruments used were an electrocautery knife, a carbon dioxide laser, a harmonic scalpel, and a neutral plasma coagulator system (i.e., Plasma JetTM). At the point of generation, geometric mean (GM) particle number concentrations ranged from 7.11E+05 particles per cubic centimeter (particles/cm^3) (geometric standard deviation (GSD): 5.68) to 7.69E+07 particles/cm^3 (GSD: 2.73). Count median diameters (CMDs) ranged from 0.034 micrometers (μm) (GSD: 1.48) to 0.095 μm (GSD: 7.99). The use of a local exhaust ventilation (LEV) control built into the electrocautery knife produced significant reductions in particle number and respirable mass concentrations. The electrocautery knife produced particles with the largest quantity of pPAHs per active surface area. Trials using both dermal and adipose tissues were conducted to determine particle size distributions and number concentrations at the personal breathing zone (PBZ) level of a worker at the surgical table. CMDs ranged from 0.028 μm (GSD: 2.0) to 0.190 μm (GSD: 2.2). GM particle number concentrations were considerably diluted compared to the point of generation by the time they reached the PBZ, ranging from 220 particles/cm^3 (GSD: 1.9) to 108,632 particles/cm^3 (GSD: 1.33). Exposure assessments were conducted during several surgical procedures with varying degrees of surgical plume produced through the use of an electrocautery knife or plasma jet. CMDs of particles ranged from 0.091 μm (GSD: 2.3) to 0.105 μm (GSD: 1.8) across the multiple surgeries measured. However, when the plasma jet was used for antibacterial purposes rather than cutting, particles of a smaller CMD, approximately 0.03 μm (GSD: 2.0), were measured. Peak particle number concentrations for the procedures with the greatest surgical plume concentrations produced between 96,000-134,000 particles/cm^3 at the measurement location located closest to the surgical table. LEV use dramatically decreased operating room concentrations compared to similar procedures when LEV was not used

Comparing Gaussian and Bessel-Gauss beams for translating ultrafast laser ablation towards soft tissue surgery

The goal of this research was to further improve existing ultrafast laser surgery techniques. To do so, different beam shapes (Bessel-Gauss and Gaussian) were compared for performing ultrashort picosecond pulsed surgery on various soft biological tissues, with the goal of minimising collateral thermal damage. Initially, theoretical modelling was performed using OpticStudio to test axicons of various conical angles. A 20° axicon was selected, but unfortunately early tests on murine intestinal tissue indicated a lack of sufficient intensity to achieve plasma-mediated ablation of the tissue with the 6ps input pulses of 85 µJ energy. Subsequently, a reimaged setup was designed in OpticStudio to demagnify the beam by a factor of 1.4x. The ability of this demagnified Bessel-Gauss beam to perform plasma-mediated ablation of murine intestinal tissue was confirmed through histological analysis. Another setup was also designed to produce a Gaussian beam of equivalent spot size. These beams were then tested on porcine intestinal tissue using lower pulse repetition rates of 1, 2 and 3 kHz, with optimal ablation and thermal damage margins of less than 20 µm (confirmed through histological analysis) being achieved with the Bessel-Gauss beam for spatial pulse overlaps of 70%, while for the Gaussian beam the prominence of cavitation bubble formation at both 2 and 3 kHz inhibited the respective ablation processes at this same spatial pulse overlap. As the numbers of passes were increased, the Bessel-Gauss beam also showed a trend of increased ablation depths. This was attributed to its large depth of focus of over 1 mm, compared to the theoretical 48 µm depth of focus for the Gaussian beam. After characterisation of fixated, non-ablated porcine intestine sample surfaces to quantify the inhomogeneity, another set of ablation trials was performed at higher pulse repetition rates (5, 10 and 20 kHz) to test more clinically viable processes. For the Bessel-Gauss beam, spatial pulse overlaps of up to around 50% at 5, 10 and 20 kHz offered excellent thermal confinement (with damage margins of < 30 µm, < 50 µm and < 25 µm respectively) and shape control, but at 70% and greater pulse overlaps the ablated feature became hard to control despite good thermal confinement (< 40 µm). The Gaussian beam, while having the advantage of achieving plasma formation at lower input pulse energies, was again found to be more prone to undesirable cavitation effects. Cavitation bubbles were observed in the histology images for spatial pulse overlaps as low as 15% for 5 kHz and 30% for both 10 and 20 kHz. From the histology images it is clear to see that these effects became more pronounced as the pulse repetition rate was increased. Conversely, the more consistent spot size of the Bessel-Gauss beam across its longer focal depth resulted in a higher tolerance to cavitation bubble formation. This was also demonstrated by high-speed videos of the beams being scanned across porcine skin samples. This could be significant as it may allow for higher ablation rates. In addition, it could ease the design constraint of the maximum speed at which the beam can be scanned at the distal end of an endoscopic device. Despite this, both beams were able to achieve distinct ablation with high thermal confinement for certain parameters. This work further highlights fibre-delivered ultrashort laser pulses as a promising alternative to existing endoscopic tumour resection techniques, which carry a higher risk of bowel perforation.James Watt Scholarshi

Surgical treatment of occipitocervical instability

Journal ArticleOBJECTIVE: Instability of the occipitocervical junction can be a challenging surgical problem because of the unique anatomic and biomechanical characteristics of this region. We review the causes of instability and the development of surgical techniques to stabilize the occipitocervical junction. METHODS: Occipitocervical instrumentation has advanced significantly, and modern modular screw-based constructs allow for rigid short-segment fixation of unstable elements while providing the stability needed to achieve successful fusion in nearly 100% of patients. This article reviews the preoperative planning, the variety of instrumentation and surgical strategies, as well as the postoperative care of these patients. RESULTS: Current constructs use occipital plates that are rigidly fixed to the thick midline keel of the occipital bone, polyaxial screws that can be placed in many different trajectories, and rods that are bent to approximate the acute occipitocervical angle. These modular constructs provide a variety of methods to achieve fixation in the atlantoaxial complex, including transarticular screws or C1 lateral mass screws in combination with C2 pars, C2 pedicle, or C2 translaminar trajectories. CONCLUSION: Surgical techniques for occipitocervical instrumentation and fusion are technically challenging and require meticulous preoperative planning and a thorough understanding of the regional anatomy, instrumentation, and constructs. Modern screw-based techniques for occipitocervical fusion have established clinical success and demonstrated biomechanical stability, with fusion rates approaching 100%