How It Works An ultrasonic wave is created by applying electromagnetic energy from the Generator 300 to a piezoelectric transducer located between metal cylinders in the hand piece. In response to the electric field, the waves, traveling as sine waves from the hand piece to the blade, create mechanical vibrations. Silicon rings are located on the positions of the blade where the amplitude of the wave is zero in order to guide the blade. 2 These mechanical vibrations then drive the active blade of the device. Vibrating 55,500 times per second, when the blade comes into contact with the tissue and pressure is applied, the blood vessels are coapted. This coaptation breaks up positive hydrogen molecules, denaturing the protein in the cells. The denatured protein then forms a sticky coagulum, which forms a hemostatic seal, allowing the surgeon to simultaneously cut and coagulate. What It Does Harmonic devices have four qualities of action: cutting, coagulation, coaptation, and cavitation. These actions can be achieved singularly or in combination with one another. In surgical procedures, all of these effects are typically applied consecutively. 2 Cutting Unlike electrosurgery, which uses extreme local heat to vaporize and disrupt tissue, Harmonic devices use a combination of tension and pressure to rapidly stretch tissue. When the tissue reaches its elastic limit, the blade or device tip is able to cut smoothly through it. 2 Coaptation Coaptation, or the adherence of tissue, is achieved by Harmonic devices disrupting hydrogen bonds, causing collagen molecules to collapse and adhere to one another at a low temperature. The tissue is then transformed into a sticky coaptate. For the preliminary control of vessels in preparing for surgery, coaptation and pressure are key.2 Coagulation By applying ultrasound energy to tissue a few seconds longer than it takes to achieve coaptation, a rise in temperature leads to the release of water vapor and then to coagulation (maximum temperature of 150°C). Rather than defragmenting protein molecules as with coaptation, coagulation is achieved by denaturizing protein. Cavitation A side effect of the ultrasonic waves used to cut, coapt, and coagulate, cavitation occurs when the high-frequency vibration of a Harmonic device is transmitted to the surrounding tissue, causing rapid volume changes of the tissue and cell fluid. Vapor bubbles are then formulated at body temperature. 2 Cavitation effect aids in tissue plane dissection, and dissecting tissue planes enhances visibility in the operative field, which can be especially beneficial in anatomically remote regions or near vital structures. 2
Provides a combination of pressure and energy to create vessel fusion Permanently fuses vessels up to and including 7 mm in diameter and tissue bundles without dissection or isolation Average seal cycle is 2 to 4 seconds* Seals withstand three times normal systolic blood pressure Feedback-controlled response system automatically discontinues energy delivery when the seal cycle is complete, eliminating the guesswork
Laparoscopy is a technologically dependent surgery.Laparoscopy is a technologically dependent surgery. Computerized designing of laparoscopic instrumentsComputerized designing of laparoscopic instruments Microprocessor controlled safety featuresMicroprocessor controlled safety featuresA laparoscopic surgeon should be technically well acknowledgedA laparoscopic surgeon should be technically well acknowledged ofofthe principle of the instrumentthe principle of the instrument being usedbeing used, and should not always depend, and should not always dependupon their technical team should an emergency arrive.upon their technical team should an emergency arrive.
Insufflation systemsInsufflation systems Insufflation system allows gas to fill the abdominopelvicInsufflation system allows gas to fill the abdominopelviccavity to optimize visualization.cavity to optimize visualization. Insufflators are designed to deliver gas at low rates duringInsufflators are designed to deliver gas at low rates duringinitial Veres needle insertion, but are also able to provide highinitial Veres needle insertion, but are also able to provide highflow rates when gas is lost to maintain a relatively constant setflow rates when gas is lost to maintain a relatively constant setintraabdominal pressure during surgery.intraabdominal pressure during surgery. Insufflation tubing with a 0.3micron filter is recommended toInsufflation tubing with a 0.3micron filter is recommended toprevent intraperitoneal contamination with bacteria,prevent intraperitoneal contamination with bacteria,microparticles and debris from insufflator and gas tank.microparticles and debris from insufflator and gas tank.
Veress needleVeress needle Spring loadedSpring loaded Blunt tip retractable into sharp sheathBlunt tip retractable into sharp sheath Small caliber penetrates tissues by separatingSmall caliber penetrates tissues by separatingrather than cuttingrather than cutting Disposable or reusableDisposable or reusable Diameter 2mm and length 12-15cmDiameter 2mm and length 12-15cm Insufflation upto 2.5L/minInsufflation upto 2.5L/min
Insufflation and abdominal liftingInsufflation and abdominal liftingsystemssystems Gases used for insufflationGases used for insufflation :: Filtered room airFiltered room air Carbon dioxideCarbon dioxide – commonly used , has advantage of being– commonly used , has advantage of beingrapidly absorbed by blood, non toxic, cost effective and can berapidly absorbed by blood, non toxic, cost effective and can beused with cauteryused with cautery Nitrous oxideNitrous oxide HeliumHelium Gasless laparoscopyGasless laparoscopy can be performed with the use of acan be performed with the use of amechanical lifting arm that attaches to a fanlike retractor alongmechanical lifting arm that attaches to a fanlike retractor alongthe peritoneal surface of the abdominal wall . This approachthe peritoneal surface of the abdominal wall . This approachfavoured in patients with cardiopulmonary risk factors.favoured in patients with cardiopulmonary risk factors.
InsufflatorsInsufflators1966-Kurt Semm introduced the concept1966-Kurt Semm introduced the concept-Automatic-Automatic-Manual-ManualIndicators-Intra abdominal pressureIndicators-Intra abdominal pressure-Flow rate-Flow rate-Total gas used-Total gas used-Cylinder capacity-Cylinder capacityThermoflatorThermoflator-Upto 20L/Min-Upto 20L/Min
Trocars and Cannulae/SleevesTrocars and Cannulae/Sleeves Used to pierce the abdominal wall for placement ofUsed to pierce the abdominal wall for placement oflaparoscope and surgical instrumentlaparoscope and surgical instrument Available as disposable or reusable systemsAvailable as disposable or reusable systems Trocar tips can be pyramidal, conical, blunt tipped, orTrocar tips can be pyramidal, conical, blunt tipped, orhave optical accesshave optical access Sizes vary from 3mm to 10mmSizes vary from 3mm to 10mm Hassons trocar and cannulaeHassons trocar and cannulae Expandable trocar sheaths are now availableExpandable trocar sheaths are now available
IMAGING SYSTEMIMAGING SYSTEMConsists of :Consists of : LaparoscopeLaparoscope Camera unitCamera unit Fiberoptic cordFiberoptic cord Light sourceLight source MonitorsMonitors
Laparoscope (Telescope)Laparoscope (Telescope) British physicist Hopkins invented in 1952British physicist Hopkins invented in 1952 Conventional Thin lens System separated by airConventional Thin lens System separated by air Present day scopes have series of rod lens in centre with rim of opticalPresent day scopes have series of rod lens in centre with rim of opticalfibers on outer aspectfibers on outer aspect Rod Hopkins System provides excellent field of vision with minimalRod Hopkins System provides excellent field of vision with minimaldistortiondistortionEND ON VIEWOUTER SHEATHLIGHTCONDUCTINGFIBRESTHE LENS CHAIN
TypesTypes Based on size and angle of visionBased on size and angle of visionSize varies from 0.8 to 12mmSize varies from 0.8 to 12mmRoutine use 10mm scopeRoutine use 10mm scope5mm scope transmits 10% light of 10mm scope5mm scope transmits 10% light of 10mm scope3mm scopes in paediatric practice3mm scopes in paediatric practice Based on angleBased on angle0 -Forward viewing0 -Forward viewing30 -Angled30 -Angled45 -Angled45 -Angled
Advantages of angled scopesAdvantages of angled scopes Unobstructed view of dissecting area from distanceUnobstructed view of dissecting area from distance More space for instrument maneuverabilityMore space for instrument maneuverability Ability to look around the cornersAbility to look around the cornersDisadvantagesDisadvantages More difficult to operateMore difficult to operateFlexible and semi flexible scopesFlexible and semi flexible scopes Fiber optic basedFiber optic based Digital CCD camera basedDigital CCD camera based
Fogging of LensFogging of Lens FoggingFogging :: due to increased temp. in abdomendue to increased temp. in abdomen PreventedPrevented by dipping tip in warm water (atby dipping tip in warm water (at6060ºCºC) & by touching liver / Abdominal Wall.) & by touching liver / Abdominal Wall. Use of Antifog solutionsUse of Antifog solutions
The CameraThe Camera Most important and vital partMost important and vital part The sensor called CCD (Charged –Coupled Device) has smallThe sensor called CCD (Charged –Coupled Device) has smallpieces of silicon called pixels, arranged in rows and columnspieces of silicon called pixels, arranged in rows and columnsand are sensitive to lightand are sensitive to light Single chipSingle chipMonitor resolution 400-450 linesMonitor resolution 400-450 lines Three chipThree chip-----analog/ digital.-----analog/ digital.Light split into RGB spectrum by prism in head of camera.Light split into RGB spectrum by prism in head of camera.Analog=GB-700 to 750 lines—medical monitorAnalog=GB-700 to 750 lines—medical monitorDigital=Enhanced quality-1000 to 1200 lines like HDTVDigital=Enhanced quality-1000 to 1200 lines like HDTV
White balancingWhite balancing Zoom optionZoom option Digital enhancementDigital enhancementCreates sharper image and contrastCreates sharper image and contrastenhancementenhancementDisadvantage is development of grainsDisadvantage is development of grainsthat distort quality of imagethat distort quality of image Disadvantage of present day Cameras is 2D visionDisadvantage of present day Cameras is 2D visionAbsence of depth perceptionAbsence of depth perception 3D Cameras3D CamerasProhibitive costProhibitive costNo clear cut benefitNo clear cut benefit
Light CablesLight CablesTwo typesTwo types1.Fluid filled cables1.Fluid filled cables2.Fiber optic cables2.Fiber optic cablesFluid filled cableFluid filled cable-Conduct more heat-Conduct more heat-Stiffer nature-Stiffer nature-Causes hinderance in maneuvering angled scopes-Causes hinderance in maneuvering angled scopes-Inability to autoclave-Inability to autoclaveFiber opticFiber optic-More user friendly-More user friendly-Fragile to be handled with care-Fragile to be handled with care-Fiber damage of >25% to replace cable-Fiber damage of >25% to replace cable
LIGHT CABLESLIGHT CABLES Fibreoptics - Multiple coaxial QuartzFibreoptics - Multiple coaxial QuartzFibres,Fibres, transmit light bytransmit light by totaltotalinternal reflectioninternal reflection.. Random or incoherent bundles transmitRandom or incoherent bundles transmitlight.light. Orientated or coherent bundles transmitOrientated or coherent bundles transmitan image.an image. Filler material that binds the bundlesFiller material that binds the bundlesabsorbs the heat and there is 30% loss inabsorbs the heat and there is 30% loss inilluminosity ( "lux" )illuminosity ( "lux" ) New fluid light" cables without fillerNew fluid light" cables without fillermaterial avoids this.material avoids this.
MonitorMonitor Should support the resolution of the cameraShould support the resolution of the camera Standard resolution monitors have a resolutionStandard resolution monitors have a resolutionof 400 linesof 400 lines High definition monitors-1200 linesHigh definition monitors-1200 lines
Hand InstrumentsHand InstrumentsUsually around 33cm longUsually around 33cm longMain partsMain parts-Handles-Handles-Shaft with insulation-Shaft with insulation-Inner effector part-Inner effector partPrerequisites for ideal Reusable instrumentsPrerequisites for ideal Reusable instruments1.Jaws to be adequately elastic to perform atraumatic handling1.Jaws to be adequately elastic to perform atraumatic handling2.Easy to disassemble and reassemble2.Easy to disassemble and reassemble3.Parts should be interchangeable between similar instruments3.Parts should be interchangeable between similar instruments4.Cleaning and sterilization to be easy4.Cleaning and sterilization to be easy5.Simple design with minimum number of hinges and bolts5.Simple design with minimum number of hinges and bolts
OPERATING INSTRUMENTSOPERATING INSTRUMENTSFollow the general pattern of being “take apart”, withFollow the general pattern of being “take apart”, with insulated sheaths,insulated sheaths, central working device,central working device, a handle with a ratchet,a handle with a ratchet, with rotary capability at the working end.with rotary capability at the working end.
LIGASURE – Vessel SealingLIGASURE – Vessel SealingSystemSystem Provides a combination of pressure and energy to create vessel fusionProvides a combination of pressure and energy to create vessel fusion Permanently fuses vessels up to and including 7 mm in diameter and tissuePermanently fuses vessels up to and including 7 mm in diameter and tissuebundles without dissection or isolationbundles without dissection or isolation Average seal cycle is 2 to 4 secondsAverage seal cycle is 2 to 4 seconds Seals withstand three times normal systolic blood pressureSeals withstand three times normal systolic blood pressure Feedback-controlled response system automatically discontinues energyFeedback-controlled response system automatically discontinues energydelivery when the seal cycle is complete, eliminating the guessworkdelivery when the seal cycle is complete, eliminating the guesswork