minimally invasive surgery, robotics, and natural

8/3/2019 Minimally Invasive Surgery, Robotics, And Natural

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yMinimally invasive surgery : an area of surgery that crosses alltraditional disciplines, from general surgery to neurosurgery.

y It is not a discipline unto itself, but more a philosophy of surgery, away of thinking.

y A means of performing major operations through small incisions,often using miniaturized, high-tech imaging systems, to minimizethe trauma of surgical exposure.


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yRobotic surgery today is practiced using a single platform andtermed computer enhanced surgery as the term roboticsassumes autonomous action that is not a feature of the da Vincirobotic system.

y The da Vinci robot couples an ergonomic workstation that featuresstereoptic video imaging and intuitive micromanipulators (surgeonside) with a set of arms delivering specialized laparoscopicinstruments enhanced with more degrees of freedom than isallowed by laparoscopic surgery alone (patient side).

y A computer between the surgeon side and patient side removessurgical tremor and scales motion to allow precise microsurgery,helpful for microdissection and difficult anastomoses.


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y Natural orifice transluminal endoscopic surgery (NOTES): a recentextension of interventional endoscopy.

y Using the mouth, the anus, the vagina, and the urethra (natural

orifices), flexible endoscopes are passed through the wall of theesophagus, stomach, colon, bladder, or vagina entering themediastinum, the pleural space, or the peritoneal cavity.

y The advantage of this method of minimal access is principally the

elimination of the scar associated with laparoscopy or thoracoscopy.


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Historical Background

y Minimally invasive surgery is relatively recent, the history of itscomponent parts is nearly 100 years old.

y Kelling in 1901: Primitive laparoscopy, placing a cystoscope withinan inflated abdomen.

y Late 1950s: Hopkins described the rod lens, a method oftransmitting light through a solid quartz rod with no heat and littlelight loss.


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y 1970s: the application of flexible endoscopy grew faster than that ofrigid endoscopy except in a few fields such as gynecology andorthopedics.

y By the mid-1970s, rigid and flexible endoscopes made a rapid

transition from diagnostic instruments to therapeutic ones.

y The explosion of video-assisted surgery in the past 20 years was aresult of the development of compact, high-resolution, charge-coupled devices (CCDs) that could be mounted on the internal endof f lexible endoscopes or on the external end of a Hopkinstelescope.


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y Flexible endoscopic imaging started in the 1960s with the firstbundling of many quartz fibers into bundles, one for illuminationand one for imaging.

y Shinya and Wolfe: first endoscopic surgical procedure was thecolonoscopic polypectomy.

y 1981: percutaneous endoscopic gastrostomy (PEG) invented byGauderer and Ponsky may have been the first NOTES procedure.


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y The first computer-assisted robot, the "RoboDoc" was designed toaccurately drill femoral shaft bone for wobble-free placement of hipprostheses.

y The robot proved no better than a skilled orthopedic surgeon and

was a good deal slower.


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Physiology and Pathophysiology of Minimally Invasive Surgery

y Even with the least invasive of the MIS procedures, physiologicchanges occur.

y Many minimally invasive procedures require minimal or nosedation, and there are few adverse consequences to thecardiovascular, endocrinologic, or immunologic systems.

y The least invasive of such procedures include stereotactic biopsy of

breast lesions and flexibleG

I endoscopy.

y Minimally invasive procedures that require general anesthesia havea greater physiologic impact because of the anesthetic agent, theincision (even if small), and the induced pneumoperitoneum.


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Laparoscopy

y The unique feature of laparoscopic surgery is the need to lift the abdominalwall from the abdominal organs.

y Two methods : The first, used by most surgeons, is a pneumoperitoneum.Intraperitoneal visualization was achieved by inflating the abdominal cavitywith air, using a sphygmomanometer bulb.

y The problem with using air insufflation is that nitrogen is poorly soluble inblood and is slowly absorbed across the peritoneal surfaces.

y Air pneumoperitoneum was believed to be more painful than nitrous oxide(N2O) pneumoperitoneum, but less painful than carbon dioxide (CO2)pneumoperitoneum.

y N2O had the advantage of being physiologically inert and rapidly absorbed. Italso provided better analgesia for laparoscopy performed under localanesthesia when compared with CO2 or air.


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y The physiologic effects of CO2pneumoperitoneum can be

divided into two areas:y gas-specific effects

y pressure-specific effects CO2 israpidly absorbed across theperitoneal membrane into thecirculation.

y In the circulation, CO2 creates arespiratory acidosis by thegeneration of carbonic acid.

y

Body buffers, the largest reserveof which lies in bone, absorb CO2(up to 120 L) and minimize thedevelopment of hypercarbia orrespiratory acidosis during briefendoscopic procedures.


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y

If the respiratory rate required exceeds 20 breaths per minute, theremay be less efficient gas exchange and increasing hypercarbia.

y If vital capacity is increased substantially, there is a greater opportunityfor barotrauma and greater respiratory motion-induced disruption ofthe upper abdominal operative field.

y It is advisable to evacuate the pneumoperitoneum or reduce the intra-abdominal pressure to allow time for the anesthesiologist to adjust forhypercarbia.

y Hypercarbiaalso causes tachycardia and increased systemic vascularresistance, which elevates blood pressure and increases myocardial

oxygen demand.


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y The pressure effects of the pneumoperitoneum on cardiovascular

physiology:

y In the hypovolemic individual, excessive pressure on the inferior venacava and a reverse Trendelenburg position with loss of lower extremitymuscle tone may cause decreased venous return and decreased cardiacoutput.

y The most common arrhythmia created by laparoscopy is bradycardia.

y A rapid stretch of the peritoneal membrane often causes a vagovagalresponse with bradycardia and, occasionally, hypotension.

y The appropriate management of this event is desufflation of theabdomen, administration of vagolytic agents (e.g., atropine), and

adequate volume replacement.


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y The increased intra-abdominal pressure compressing the inferior

vena cava, there is diminished venous return from the lowerextremities.

y In short-duration laparoscopic procedures, such as appendectomy,hernia repair, or cholecystectomy, the risk of DVT may not be

sufficient to warrant extensive DVT prophylaxis.


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y The increased pressure of the pneumoperitoneum is transmitteddirectly across the paralyzed diaphragm to the thoracic cavity, creatingincreased central venous pressure and increased filling pressures of theright and left sides of the heart.

y If the intra-abdominal pressures are kept under 20 mmHg, the cardiacoutput usually is well maintained.The direct effect of thepneumoperitoneumon increasing intrathoracic pressure increases

peak inspiratory pressure, pressure across the chest wall, and also, thelikelihood of barotrauma.

y Increased intra-abdominal pressure decreases renal blood flow,glomerular filtration rate, and urine output. These effects may bemediated by direct pressure on the kidney and the renal vein.The

secondary effect of decreased renal blood flow is to increase plasmarenin release, thereby increasing sodium retention.


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y Intraoperative oliguria is common during laparoscopy, but the urine

output is not a reflection of intravascular volume status; IV fluidadministration during an uncomplicated laparoscopic procedureshould not be linked to urine output.

y Insensible fluid losses through the open abdomen are eliminated

with laparoscopy, the need for supplemental f luid during alaparoscopic surgical procedure should only keep up with venouspooling in the lower limbs, third-space losses into the bowel, andblood loss, which is generally less than occurs with an equivalentopen operation.


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y Endocrine responses to laparoscopic surgery are not always intuitive.S

erum cortisol levels after laparoscopic operations are often higherthan after the equivalent operation performed through an openincision.

y The greatest difference between the endocrine response of open andlaparoscopic surgery is the more rapid equilibration of most stress-

mediated hormone levels after laparoscopic surgery.

y Immune suppression also is less after laparoscopy than after opensurgery.There is a trend toward more rapid normalization of cytokinelevels after a laparoscopic procedure than after the equivalent

procedure performed by celiotomy.


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y Transhiatal mobilization of the distal esophagus is commonly

performed as a component of many laparoscopic upper abdominalprocedures.

y If there is compromise of the mediastinal pleura with resultant CO2pneumothorax, the defect should be enlarged so as to prevent a tension

pneumothorax.

y A thoracostomy tube (chest tube) should be placed across the breachinto the abdomen with intra-abdominal pressures reduced below 8mmHg, or a standard chest tube may be placed.


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Thoracoscopy

y The physiology of thoracic MIS (thoracoscopy) is different from that oflaparoscopy.

y The bony confines of the thorax, it is unnecessary to use positivepressure when working in the thorax.

y The disadvantages of positive pressure in the chest include:

y decreased venous return, mediastinal shift, and the need to keep afirm seal at all trocar sites.


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Extracavitary Minimally Invasive Surgery

y Many MIS procedures create working spaces in extrathoracic andextraperitoneal locations.

y Laparoscopic inguinal hernia repair usually is performed in the

anterior extraperitoneal Retzius space.

y Laparoscopic nephrectomy often is performed with retroperitoneallaparoscopy. Endoscopic retroperitoneal approaches to pancreaticnecrosectomy have seen some limited use.


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y Lower extremity vascular procedures and plastic surgicalendoscopic procedures require the development of working

space in unconventional planes, often at the level of the fascia,sometimes below the fascia, and occasionally in nonanatomicregions.

y Some of these techniques use insufflation of gas, but many useballoon inf lation to develop the space, followed by low-pressure

gas insufflation or lift devices to maintain the space.

y These techniques produce fewer and less severe adversephysiologic consequences than does the pneumoperitoneum,but the insufflation of carbon dioxide into extraperitoneallocations can spread widely, causing subcutaneous emphysemaand metabolic acidosis.


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Balloons are used to create extra-anatomic working spaces. In this example (Athrough C), a balloon is introduced into the space between the posterior rectussheath and the rectus abdominal muscle. The balloon is inflated in the preperitoneal space to create working room forextraperitoneal endoscopic hernia repair


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The Minimally Invasive Team

y Minimally invasive procedures require complicated and fragileequipment that demands constant maintenance

y Multiple intraoperative adjustments to the equipment, camera,insufflator, monitors, and patient/surgeon position are made during

these procedures.

y A coordinated team approach is mandated to ensure patient safety andexcellent outcomes. More and more, flexible endoscopes are used toguide or provide quality control for laparoscopic procedures.

y

AsNOTES

evolves, hybrid procedures (laparoscopy and endoscopy)and sophisticatedNOTES technology will require a nursing staffcapable of maintaining f lexible endoscopes and understanding theoperation of sophisticated endoscopic technology.


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Room Setup and the Minimally Invasive Suite

y Nearly all MIS, whether using fluoroscopic, ultrasound, oroptical imaging, incorporates a video monitor as a guide.

y Occasionally, two images are necessary to adequately guide the

operation, as in procedures such as endoscopic retrogradecholangiopancreatography, laparoscopic common bile ductexploration, and laparoscopic ultrasonography.

y The video monitor(s) should be set across the operating table

from the surgeon. The patient should be interposed between thesurgeon and the video monitor; ideally, the operative field alsolies between the surgeon and the monitor.


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y The development of theminimally invasive surgical suitehas been a tremendouscontribution to the field oflaparoscopy.

y The core equipment:

y monitors, insufflators andimaging equipment


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y The specifically designed minimally invasive surgical suite serves to:

y decrease equipment and cable disorganization

y ease the movements of operative personnel around the room

y improve ergonomics

y facilitate the use of advanced imaging equipment such aslaparoscopic ultrasound.


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Patient Positioning

y Patients usually are placed in the supine position for laparoscopicsurgery.

y When the operative field is the gastroesophageal junction or the leftlobe of the liver, it is easiest to operate from between the legs.

y The legs may be elevated in Allen stirrups or abducted on leg boards toachieve this position.

y When pelvic procedures are performed, it usually is necessary to placethe legs in Allen stirrups to gain access to the perineum.


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y Nephrectomy or adrenalectomy:

y

A lateral decubitus position withthe table flexed provides thebest access to theretroperitoneum.

y Laparoscopic splenectomy:

y a 45-tilt of the patient providesexcellent access to the lesser sacand the lateral peritonealattachments to the spleen.

y Thoracoscopic surgery:

y The patient is placed in thelateral position with tableflexion to open the intercostalspaces and the distance betweenthe iliac crest and costal margin.


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General Principles of Access

y The most natural ports of access for MIS and NOTES are the anatomicportals of entry and exit.

y The nares, mouth, urethra, and anus are used to access the respiratory,GI, and urinary systems.

y

The advantage of using these points of access is that no incision isrequired.

y The disadvantages lie in the long distances between the orifice andthe region of interest.

yForNOTES procedures, the vagina may serve as another point ofaccess, entering the abdomen via the posterior culde-sac of the pelvis.Similarly, the peritoneal cavity may be reached through the side wall ofthe stomach or colon.


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y Thoracoscopic surgery, the access technique is similar to that usedfor placement of a chest tube.

y In these procedures general anesthesia and single lung ventilationare essential.

y A small incision is made over the top of a rib and, under directvision, carried down through the pleura.

y The lung is collapsed, and a trocar is inserted across the chest wallto allow access with a telescope. Once the lung is completelycollapsed, subsequent access may be obtained with direct puncture,

viewing all entry sites through the videoendoscope.


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Laparoscopic Access

y The requirements for laparoscopy are more involved, because thecreation of a pneumoperitoneum requires that instruments of access(trocars) contain valves to maintain abdominal inflation.

y Two methods are used for establishing abdominal access during

laparoscopic procedures.y The first, direct puncture laparoscopy, begins with the elevation of the

relaxed abdominal wall with two towel clips or a well-placed hand.

y A small incision is made in the umbilicus, and a specialized spring-loaded (Veress) needle is placed in the abdominal cavity.

y With the Veress needle, two distinct pops are felt as the surgeon passesthe needle through the abdominal wall fascia and the peritoneum.


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A.Insufflation of the abdomen is accomplished with a Veress needle held at itsserrated collar with a thumb and forefinger.

B. Because linea alba is fused to the umbilicus, the abdominal wall is grasped

with fingers or penetrating towel clip to elevate the abdominal wall away from

the underlying structures.


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y The umbilicus usually is selected as the preferred point of accessbecause, in this location, the abdominal wall is quite thin, even in

obese patients.

y The abdomen is inflated with a pressure-limited insufflator.

y CO2 gas usually is used, with maximal pressures in the range of 14 to 15mmHg.

y During the process of insufflation, it is essential that the surgeonobserve the pressure and flow readings on the monitor to confirm anintraperitoneal location of the Veress needle tip.


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y After peritoneal insufflation, direct access to the abdomen is

obtained with a 5- or 10-mm trocar.

y The critical issues for safe direct-puncture laparoscopy include theuse of a vented stylet for the trocar, or a trocar with a safety shield ordilating tip.

y The trocar must be pointed away from the sacral promontory andthe great vessels.

y

Patient position should be surveyed before trocar placement toensure a proper trajectory.

y For performance of laparoscopic cholecystectomy, the trocar isangled toward the right upper quadrant.


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y

TwoKocher clamps are placedon the fascia, and with curvedMayo scissors, a small incisionis made through the fascia andunderlying peritoneum.

y A finger is placed into theabdomen to make sure thatthere is no adherent bowel.

y A sturdy suture is placed on

each side of the fascia andsecured to the wings of aspecialized trocar, which isthen passed directly into theabdominal cavity.


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y Rapid insufflation can make up for some of the time lost with the

initial dissection.

y This technique is preferable for the abdomen of patients who haveundergone previous operations in which small bowel may beadherent to the undersurface of the abdominal wound.

y The difficulties in visualizing the abdominal region immediatelyadjacent to the primary trocar, it is recommended that the telescopebe passed through a secondary trocar to inspect the site of initialabdominal access.

y Secondary punctures are made with 5- and 10-mm trocars. For safeaccess to the abdominal cavity, it is critical to visualize all sites oftrocar entry.


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y At the completion of the operation, all trocars are removed underdirect vision, and the insertion sites are inspected for bleeding.

y If bleeding occurs, direct pressure with an instrument from anothertrocar site or balloon tamponade with a Foley catheter placedthrough the trocar site generally stops the bleeding within 3 to 5minutes.

y When this is not successful, a full-thickness abdominal wall suturehas been used successfully to tamponade trocar site bleeding.


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Access for Subcutaneous and Extraperitoneal Surgery

y For retroperitoneal locations, balloon dissection is effective.y This access technique is appropriate for the extraperitoneal repair of

inguinal hernias and for retroperitoneal surgery for adrenalectomy,nephrectomy, lumbar discectomy, pancreatic necrosectomy, or para-aortic lymph node dissection.

y The initial access to the extraperitoneal space is performed in a waysimilar to direct puncture laparoscopy, except that the last layer (theperitoneum) is not traversed.

y Once the transversalis fascia has been punctured, a specialized trocar

with a balloon on the end is introduced.

y The balloon is inflated in the extraperitoneal space to create a workingchamber. The balloon then is deflated and a Hasson trocar is placed.


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y An insufflation pressure of 10 mmHg usually is adequate to keep

the extraperitoneal space open for dissection and will limitsubcutaneous emphysema.

y Higher gas pressures force CO2 into the soft tissues and maycontribute to hypercarbia.

y Extraperitoneal endosurgery provides less working space thanlaparoscopy but eliminates the possibility of intestinal injury,intestinal adhesion, herniation at the trocar sites, and ileus.


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y S

ubcutaneous surgery has been most widely used in cardiac, vascular,and plastic surgery.

y In cardiac surgery, subcutaneous access has been used for saphenousvein harvesting, and in vascular surgery for ligation of subfascialperforating veins (Linton procedure).

y With minimally invasive techniques, the entire saphenous vein abovethe knee may be harvested through a single incision.

y Once the saphenous vein is located, a long retractor that holds a 5-mmlaparoscope allows the coaxial dissection of the vein and coagulation orclipping of each side branch.

y A small incision above the knee also can be used to ligate perforatingveins in the lower leg.


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A.With two small incisions, virtually the entire saphenous vein can be

harvested for bypass grafting.

B. The lighted retractor in the subcutaneous space during saphenous vein

harvest is seen illuminating the skin.


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Hand-Assisted Laparoscopic Access

y Thought to combine the tactile advantages of open surgery with theminimal access of laparoscopy and thoracoscopy.

y This approach commonly is used to assist with difficult cases before

conversion to celiotomy is necessary.y Used to help surgeons negotiate the steep learning curve associated

with advanced laparoscopic procedures.

y This technology uses a "port" for the hand that preserves the

pneumoperitoneum and enables endoscopic visualization incombination with the use of minimally invasive instruments .


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This is an example ofhand-assisted laparoscopic surgery during left colectomy.The surgeon uses a hand to provide retraction and counter tension during

mobilization of the colon from its retroperitoneal attachments, as well as

during division of the mesocolon. This technique is particularly useful in the

region of the transverse colon.


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Port Placement

y Trocars for the surgeon's left andright hand should be placed at

least 10 cm apart.

y The ideal trocar orientationcreates an equilateral triangle

between the surgeon's right hand,left hand, and the telescope, with10 to 15 cm on each leg.

y If one imagines the target of the

operation (e.g., the gallbladder orgastroesophageal junction)oriented at the apex of a secondequilateral triangle built on thefirst, these four points of referencecreate a diamond

y The surgeon stands behind thetelescope, which providesoptimal ergonomic orientationbut frequently requires that acamera operator (or mechanicalcamera holder) reach betweenthe surgeon's hands to guide thetelescope.


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Imaging Systems

y Two methods of videoendoscopic imaging are widely used.

y Both methods use a camera with a CCD, which is an array ofphotosensitive sensor elements (pixels) that convert the incoming lightintensity to an electric charge.

y The electric charge is subsequently converted into a black-and-whiteimage.

y Videoendoscopy, the CCD chip is placed on the internal end of a long,flexible endoscope.

y Most standard GI endoscopes have the CCD chip at the distal end, butsmall, delicate choledochoscopes and nephroscopes are equipped withfiber-optic bundles.


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y Priorities in a video imaging system for MIS are

y illumination

y resolution

y color third

y Without the first two attributes, video surgery is unsafe.

y Illumination and resolution are as dependent on the telescope, lightsource, and light cable as on the video camera used. Imaging forlaparoscopy, thoracoscopy, and subcutaneous surgery uses a rigid metaltelescope, usually 30 cm in length.

y Little illumination is needed in highly reflective, small spaces such asthe knee, and a very small telescope will suffice.

y When working in the abdominal cavity, especially if blood is present,the full illumination of a 10-mm telescope usually is necessary.


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y Rigid telescopes may have a flat or angledend.

y Flat end provides a straight view (0),

y Angled end provides an oblique view(30 or 45)

y Angled telescopes allow greater flexibilityin viewing a wider operative field through

a single trocar site rotating an angledtelescope changes the field of view.

y The use of an angled telescope hasdistinct advantages for mostvideoendoscopic procedures, particularlyin visualizing the common bile ductduring laparoscopic cholecystectomy orvisualizing the posterior esophagus or thetip of the spleen during laparoscopicfundoplication.


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y The quality of thevideoendoscopic image is only as

good as the weakest componentin the imaging chain .

y It is important to use a videomonitor that has a resolution

equal to or greater than thecamera being used.

y Resolution is the ability of theoptical system to distinguishbetween line pairs. The larger thenumber of line pairs permillimeter, the sharper and moredetailed the image.

The Hopkins rod lens telescope includes a series ofoptical rods that effectively transmit light to the eyepiece.The video camera is placed on the eyepiece to provide theworking image. The image is only as clear as the weakestlink in the image chain. CCD = charge-coupled device.


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Energy Sources for Endoscopic and Endoluminal Surgery

y Many MIS procedures use conventional energy sources, but thebenefits of bloodless surgery to maintain optimal visualization hasspawned new ways of applying energy.

y The most common energy source is RF electrosurgery using analternating current with a frequency of 500,000 cycles/s (Hz).

y Tissue heating progresses through the well-known phases of

coagulation [60C (140F

)], vaporization and desiccation [100C(212F)], and carbonization [>200C (392F)].


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y The two most common methods of delivering RF electrosurgery arewith monopolarand bipolar electrodes.

y Monopolarelectrosurgery, a remote ground plate on the patient's leg orback receives the flow of electrons that originate at a point source, thesurgical electrode.

y A fine-tipped electrode causes a high current density at the site ofapplication and rapid tissue heating.

y A short-duration, high-voltage discharge of current (coagulationcurrent) provides extremely rapid tissue heating.

y Lower-voltage, higher-wattage current (cutting current) is better fortissue desiccation and vaporization.

y When the surgeon desires tissue division with the least amount ofthermal injury and least coagulation necrosis, a cutting current is used.


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y Bipolar electrosurgery, the electrons

flow between two adjacentelectrodes.

y The tissue between the twoelectrodes is heated and desiccated.

y There is little opportunity for tissuecutting when bipolar current is used,but the ability to coapt the electrodesacross a vessel provides the best

method of small-vessel coagulationwithout thermal injury to adjacenttissues.


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A. Capacitive coupling occurs as a result of high current density bleedingfrom a port sleeve or laparoscope into adjacent bowel.

B. Direct coupling occurs when current is transmitted directly from theelectrode to a metal instrument or laparoscope, and then into adjacenttissue.


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Instrumentation

y Hand instruments for MIS usually are duplications of conventionalsurgical instruments made longer, thinner, and smaller at the tip.

y It is important to remember that when grasping tissue with

laparoscopic instruments, a greater force is applied over a smallersurface area, which increases the risk for perforation or injury.


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y Certain conventional instruments such as scissors are easy to reproducewith a diameter of 3 to 5 mm and a length of 20 to 45 cm, but otherinstruments such as forceps and clamps cannot provide remote access.

y Different configurations of graspers were developed to replace thevarious configurations of surgical forceps and clamps.

y Standard hand instruments are 5 mm in diameter and 30 cm in length,but smaller and shorter hand instruments are now available forpediatric surgery, for microlaparoscopic surgery, and for arthroscopicprocedures.

y A unique laparoscopic hand instrument is the monopolar electricalhook. Configured with a suction and irrigation apparatus to eliminate

smoke and blood from the operative field.y Allows tenting of tissue over a bare metal wire with subsequent

coagulation and division of the tissue.


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Robotic Surgery

y Robot defines a device that has beenprogrammed to perform specific tasks inplace of those usually performed by people.

y The devices that have earned the title

"surgical robots" would be more aptly termedcomputer-enhanced surgical devices, as theyare controlled entirely by the surgeon for thepurpose of improving performance.

y The first computer-assisted surgical devicewas the laparoscopic camera holder, whichenabled the surgeon to maneuver thelaparoscope either with a hand control, footcontrol, or voice activation.


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y The surgeon is physicallyseparated from the operatingtable, and the working arms ofthe device are placed over thepatient.

y An assistant remains at thebedside and changes theinstruments as needed, providingretraction as needed to facilitatethe procedure.


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Natural Orifice Transluminal Endoscopic Surgery

y The "latest rage" in MIS is NOTES, the use of the flexible endoscope toenter theGI, urinary, or reproductive tracts, then traverse the wall ofthe structure to enter the peritoneal cavity, the mediastinum, or thechest.

y The catalyzing event for NOTES was the demonstration that a porcinegallbladder could be removed with a flexible endoscope passedthrough the wall of the stomach, then removed through the mouth,and the demonstration in a series of 10 human cases from India of theability to perform transgastric appendectomy.

y Since that time, a great deal of money has been invested by endoscopicand MIS companies to help surgeons and gastroenterologists explorethis new territory.


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Transgastric cholecystectomy using natural orifice transluminal endoscopicsurgery technology and one to three laparoscopic ports has been performedoccasionally in several locations around the world.


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Pediatric Laparoscopy

y MIS in the adolescent is little different from that in the adult, andstandard instrumentation and trocar positions usually can be used.

y The instruments are shorter (15 to 20 cm), and many are 3 mm indiameter rather than 5 mm.

y The abdomen of the child is much smaller than that of the adult, a 5-mm telescope provides sufficient illumination for most operations.

y The development of 5-mm clippers and bipolar devices has obviatedthe need for 10-mm trocars in pediatric laparoscopy.

y Abdominal wall is much thinner in infants, a pneumoperitoneumpressure of 8 mmHg can provide adequate exposure. DVT is rare inchildren, so prophylaxis against thrombosis probably is unnecessary.


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Laparoscopy during Pregnancy

y Concerns about the safety of laparoscopic cholecystectomy or appendectomy inthe pregnant patient have been thoroughly investigated and are readilymanaged.

y Access to the abdomen in the pregnant patient should take into consideration

the height of the uterine fundus, which reaches the umbilicus at 20 weeks.

y The patient should be positioned slightly on the left side to avoid compressionof the vena cava by the uterus. Pregnancy poses a risk for thromboembolism,sequential compression devices are essential for all procedures.

y Fetal acidosis induced by maternal hypercarbia also has been raised as aconcern. The arterial pH of the fetus follows the pH of the mother linearly; andtherefore, fetal acidosis may be prevented by avoiding a respiratory acidosis inthe mother.


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Minimally Invasive Surgery and Cancer Treatment

y MIS techniques have been used for many decades to provide palliationfor the patient with an obstructive cancer.

y Laser treatment, intracavitary radiation, stenting, and dilation are

outpatient techniques that can be used to re-establish the continuity ofan obstructed esophagus, bile duct, ureter, or airway.

y Used in the staging of cancer.

y Laparoscopy also is used to assess the liver in patients being evaluatedfor pancreatic, gastric, or hepatic resection.


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Cirrhosis and Portal Hypertension

y Patients with hepatic insufficiency pose a significant challenge for anytype of surgical intervention.y The ultimate surgical outcome in this population relates directly to the

degree of underlying hepatic dysfunction.

y Often, this group of patients has minimal reserve, and the stress of an

operation will trigger complete hepatic failure or hepatorenalsyndrome.These patients are at risk for major hemorrhage at all levels,including trocar insertion, operative dissection in a field of dilatedveins, and secondary to an underlying coagulopathy.

y Ascitic leak from a port site may occur, leading to bacterial peritonitis.Therefore, a watertight port site closure should be carried out in allpatients.

y The presence of portal hypertension is a relative contraindication tolaparoscopic surgery until the portal pressures are reduced with portaldecompression.


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Economics of Minimally Invasive Surgery

y Minimally invasive surgical procedures reduce the costs of surgery mostwhen length of hospital stay can be shortened and return to work isquickened.

y

Shorter hospital stays can be demonstrated in laparoscopiccholecystectomy,Nissen fundoplication, splenectomy, andadrenalectomy. Procedures such as inguinal herniorrhaphy that arealready performed as outpatient procedures are less likely to providecost savings.

y Procedures that still require a 4- to 7-day hospitalization, such aslaparoscopy-assisted colectomy, are less likely to deliver a lower bottomline than their open surgery counterparts.


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minimally invasive surgery, robotics, and natural

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