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Recent advances in endoscopic entry techniques
Recent advances in endoscopic entry techniques Artin Ternamian M D F R C S C
Abstract The most important and potentially dangerous first step in laparoscopy is safe and successful insertion o f the primary cannula. Several entry techniques and instruments are reviewed to illustrate different entry options available to endoscopists. Conventional entry methods use the push-through trocar and cannula design. Considerable axial penetration force is applied to thrust a sharp trajectory into the abdomen. Concern regarding their safety has been expressed when used at primary port, especially in high risk patients and those who have had previous abdominal surgery. Different variations of this blind entry technique attempt to render port insertion safer. However, the push-through principal is retained and surgeons cannot anticipate, avoid or recognise entry injury. Most surgeons agree that visually controlled entry techniques infer added safety and render the process inter[active. Newer optical entry methods allow error recognition when accidents occur and error recovery is POssible before the accident progresses to patient harm. Visually controlled entry systems that require no sharp trocar, apply no axial penetration force, and render this critical first step in laparoscopy more error tolerant. Visual systems allow error analysis and improve our understanding o f laparoscopic entry complications. Ultiinately, endoscopists must be well versed in more than one entry technique, as primary port insertion must be tailored to meet the specific physical and medical needs of each patient. Surgeons must use those entry methods and instruments that they are schooled in and feel safest in their hands. Keywords: laparoscopy, entry technique, access cannula, trocar, ENDOTIP ~, visual cannula
Introduction Endoscopy allows optically guided procedures to be performed within the body, through surgically created temporary ports (laparoscopy, thoracoscopy) or through a natural conduit, without requiring an access wound (hysteroscopy, bronchoscopy). These operations are practiced in most specialties and have b e c o m e a p r e f e r r e d m e t h o d o f diagnosis and treatment of several surgical conditions. Endoscopy is a dynanfic discipline that is quickly evolving and now includes high-resolution imaging technology, allowing frameless stereotactic surgery. The most important and potentially dangerous first step in laparoscopic s u r g e r y is safe and successful insertion of a primary port t.
Division of Gynecologic Endoscopy St. Joseph's Health Centre University of Toronto 77 Truman Rd Toronto, Ontario Canada M2L 2L7 e:maih [email protected]
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Conventional First Generation laparoscopic entry techniques, using the Veress needle and sharp pushthrough trocar and cannula, remain the most commonly used entry method and complications related to their use are well documented2. As more surgical specialties practise laparoscopy, the n u m b e r o f patients w i t h umbilical scars increase. M o r e o v e r , c o n v e n t i o n a l m e t h o d s o f blind umbilical w i m a r y peritoneal entry may not be u n i f o r m l y acceptable. Surgeons p e r f o r m i n g sophisticated operations nmst now be versed in several alternate laparoscopic entry methods and imtrmnents to address evolving safety requirements and patient expectations. P u b l i c a t i o n o f the Institute O f M e d i c i n e comnfittee report on Patient Safety, and the US Congress initiative on prevention of medical error, prompted surgeons and industry to recognise the need for less hazardous laparoscopic entry options especially in high-risk situations. It is believed that 90% o f unintended medical mishaps are human error related3. Therefore, entry methods that can anticipate, avoid or at the v e r y least recognise e r r o r is
Volume 1 (2) Summer 200t
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Recent advances in endoscopic entry techniques Temamian A advocated, where error recovery is possible, before permanent patient harm occurs4. This r e v i e w outlines d i f f e r e n t m e t h o d s o f Primary and Ancillary laparoscopic port insertion and describes recent advances in entry techniques.
4. Micro-laparoscopy Optical Veress direct insertion
Second Generation Entry Technique (Optical Camlula design, Spin Principle) Endoscopic Threaded Imaging Port
Dynamics during port Insertion
ENDOTIP ~
The taxononw of laparoscopic entry injury is best understood when the dynamics at port site are studied and careful error analysis is conducted to unravel the interaction between tissue, instrument and surgeon. Generally, two entry methods are available during laparoscopy. First Generation conventional entry technique, where the push-through spike principle is applied tO place a trocar and cannula design trajectory intraperitoneally, The surgeon palms the access instrument by the d o n l i n a n t tland, and g e n e r a t e s c o n s i d e r a b l e penetration force by the upper arm muscles. This force is applied axially at the port site, for the spike to transect different tissue layers on its way into the abdomen. Several versions, modifications and models have attempted to render this entry system less perilous while maintaining the basic spike and cannula design principle. Second Generation entry technique, uses the spin principle, w h e r e no axial p e n e t r a t i o n force is applied; an optically guided cannula pulls tissues up along an outside thread. Tissue layers are radially parted instead of being transected by a sharp or bevelled central trocar. A laparoscope, mounted into the cannula, replaces the trocar, to offer visually controlled port placement5.
Endoscopic entry techniques First generation entry technique (Trocar & cammla design, spike principle) .
Closed entry pre-insufflation direct insertion radially expanding trocar high pressure insufflation
2.
Open Hasson's entry direct insertion
3.
Optical entry pre-insufflation
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pre-insuftlation direct insertion extra peritoneal insufflation
First generation entry technique The primary port is the first access site through which a camera, lens and light is introduced. Its insertion is a critical first step during laparoscopy when most serious injuries occur. Veress or trocar placement is particularly perilous, as considerable uncontrolled axial force is applied blindly to sharp instruments. Moreover, all practitioners agree that subsequent ancillary ports must be inserted under direct vision, as it is a c c e p t e d that visually controlled entry is safer. During 'Closed' entry laparoscopy, most surgeons insufflate before insertion o f the primary port. However, some endoscopists prefer alternate closed entry methods. A few small studies suggest that direct primary trocar insertion before insufflation may cause fewer entry complications6-8. Direct trocar insertion advocates r e c o m m e n d elevation o f the anterior abdonfinal wall while inserting the sharp pr!mary trocar directly and blindly towards the peritoneal cavity. The COz gas stopcock is kept open, for the negative intraabdominal pressure to be relieved as the vented instrument tip enters the potential peritoneal space. It is suggested that the viscera fall off its parietal apposition prior to contact with the advancing sharp trocar. (Figure 1) Published data generally do not support the conclusion that 'Direct' entry is any safer than conventional 'Closed' entry. Studies recommending this entry method are too small to make reliable statistically valid observations. Ma~W surgeons find insertion of a sharp trocar blindly into an noninsufflated abdomen potentially hazardous and indefensible. Bowel injury has been reported as a c o n s e q u e n c e o f the 'Direct' entry technique. Certainly larger trials are necessary to better understand this blind insertion method.
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Recent advances in endoscopic entry techniques Temanfian A
Figure 1: Conventional sharp pyramidal trocarand cammla. Available e v i d e n c e d e m o n s t r a t e that vascular injuries are seven times more likely to be caused by either the primary or ancillary trocar placement than by the Veress n e e d l e 9. In a n a t i o n w i d e prospective m u l t i c e n t r i c D u t c h study, Jansen reviewed 25,764 laparoscopies. Five complications w e r e caused by the Veress n e e d l e and 68 by insertion of the trocar t0 Gasless l a p a r o s c o p y is a n o t h e r m e t h o d o f endoscopy where insufflation is not utilised. The primary port site is dissected down to peritoneum, special abdominal wall lifters, attached to the operating table are required. T h e a b d o m e n is tented to create a peritoneal working compartment where different trocars are inserted directly. This method does not seem to offer as uniform a displacement o f viscera as p n e u m o - p e r i t o n e u m does. It allows use o f conventional laparoton W i n s t r u m e n t s and r e d u c e s the l a p a r o s c o p i c operation's learning curve tl. Several abdominal lifting instruments are available, some are intrusive and most surgeons prefer the c o n v e n t i o n a l insuttlated method. Radially expanding disposable trocar systems use an expanding outer sleeve that fits over a Veress needle. The abdomen is first insufflated, then the Veress needle removed. A trocar is then inserted into the sleeve that gradually expands to accommodate the trocar's diameter. The central spike is then replaced with a laparoscope t2.
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High pressure CO2 gas insufflation technique is a variation on the classic closed insertion method where insufflation to an intra-peritoneal pressure of 25 m m H g or higher is attained using a Veress needle. This splints better the anterior abdominal wall against axial penetration force and interposes a larger C O 2 gas cushion between the advancing t r a j e c t o r y and great vessels or a b d o m i n a l viscera. Bowel adherent to parietal abdominal wall remains susceptible to injury, as insertion is blind. Once a cannula is placed and correct insertion verified intra-peritoneal pressure is lowered to 10-15 m m H g a3-ts. Although multiple-use and single-use trocars are available, there is a movement back to reusable instruments. Environmentally conscious and fiscally strained health care systems generally advocate purchase of reusables 16. Moreover, nmltiple use of a single-use-designated instrument, especially a trocar is generally not recommendedaL Unfortunately, surgeons have less say in theatre p u r c h a s i n g decisions and are only called to defend outcome when mishaps occur. Most publications extol the virtues o f sharp trocars; it is generally accepted that they require less penetration force to traverse anterior abdominal layers, c o m p a r e d w i t h a less sharp trocart8. Adnfittedly, the extreme sharpness o f disposable e n t r y i n s t r u m e n t s may make i n s e r t i o n less controlled, where the risk of inadvertent bowel or vessel injury is higher. In some series, the risk of bowel injury with disposable trocars is about three times that previously reported for reusable trocars. T h e m a j o r i t y o f disposable trocars w i t h an a u t o m a t i c a l l y e x t e n d i n g 'safety' shield w e r e designed to decrease risk o f inadvertent injury. However, the US Food and Drug Administration n o w requires all d e v i c e m a n u f a c t u r e r s and distributors of shielded access cammlas to eliminate claims o f added 'safety q9. As visualisation o f the primary port is impossible, except w h e n using optical entry cannulas, it is advisable to always inspect the inner aspect of the primary entry site, through one o f the ancillary ports at the end of each laparoscopy. 1. C l o s e d l a p a r o s c o p i c primary entry technique Inspection o f the supine non-draped abdomen, n o t i n g o f p r e v i o u s surgical scars, a b d o m i n a l palpation and identification o f bony landmarks
Volume 1 (2) Summer 2001
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Recent advances in endoscopic entry techniques Temamian A must precede every laparoscopic primary port insertion. An umbilical skin incision is made, followed by insertion o f the Veress needle to distend the peritoneal cavity with C O 2 gas. This braces the abdominal wall to offer counter pressure against the considerable axial penetration force applied. The gas cushion, interposed b e t w e e n an advancing sharp trocar and abdominal viscera may avoid unintended injury. In addition, a gas filled spacious inert cavity allows unobstructed visualisation o f organs during surgery. T h e spring-loaded needle is first tested and stopcock kept open to allow room air to stream into the vacuum-sealed peritoneal cavity as soon as the peritoneal membrane is penetrated. The Veress needle, held at the hub by the dominant hand, is vertically inserted towards the peritoneum. Generally i w o distinct "pops" are felt as the needle passe s first through-anterior rectus fascia, then through posterior fascia and peritoneum. Once a second pop is felt, the needle is directed towards the pelvis 20- W h e n insertion is intraumbilical, only one pop is felt. D e t e r m i n i n g c o r r e c t p l a c e m e n t p r i o r to insuffiation is very important, as failure to achieve and maintain p n e u m o p e r i t o n e u m is a c o m m o n cause o f procedural failure. It is important to closely follow intra-peritoneal pressure changes during insufflation and keep the flow rate initially at less than one litre per minute. Inadvertent improper Veress needle placement and a high flow rate may lead to serious complications. O n c e correct needle placement is verified, the flow rate may be increased. The maximal accepted intraperitoneal pressure is 15 mmHg. It is accepted that obesity does not adversely affect insuffiated C O 2 volume for a given intra abdominal pressure. The actual intra-abdominal volume is a finite value, and 94% of this capacity is achieved at an abdominal pressure of 15 mmHg21. W h e n higher pressures are recorded d u r i n g insufflation, the position of the needle is changed by gently drawing out or moving it sideways, to dislodge the tip that may be against a viscus. Alternatively, the a b d o m i n a l wall c o u l d be manually elevated with similar results. Injecting a few millilitres of saline could also be tried. It is important to make sure that the patient is well anaesthetised as " b u c k i n g " could give similar
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readings. When all fails, it is better to remove the Veress, inspect for malfunction and then reinsert it anew.
Manual abdominal palpation remains a preferred method o f determining degree o f distention, as measurement o f total volume o f instilled gas is unreliable. Having attained adequate insufflation, the Veress needle is removed and the conventional trocar and cannula is inserted towards the distended peritoneal cavity blindly. This basic entry principal has not changed nmch since its inception. 2. O p e n laparoscopic p r i m a r y entry technique In 1971 H. Hasson first introduced a primary port insertion m e t h o d w h e r e a Veress needle and p r e - i n s u f f l a t i o n is n o t r e q u i r e d . A g e n e r o u s u m b i l i c a l skin i n c i s i o n is made and the subcutaneous layer dissected to expose the anterior rectus fascia. S-shaped retractors facilitate exposure. Two Kocher clamps hold the fascia and stay sutures are placed at 3 and 9 o'clock. The anterior fascia is incised between the two sutures using a curved long Mayo scissors and the exposed peritoneum is entered using a blunt snap 22. A finger is then inserted into the peritoneal w i n d o w to ensure absence o f adhesions. T h e Hasson trocar and cannula is then introduced and secured to the fascia using the stay sutures. A cone shaped obturator further discourages gas leakage around the cannula's stem. (Figure 2). Several variations on this intuitive method have been described, h o w e v e r the access principle remains the same and an increasing number o f surgeons prefer this m e t h o d , especially w h e n inserting ports in patients who have had previous abdominal surgery and parietal adhesions are suspected. Although the possibility o f access injury to adherent viscera at the immediate port site is not entirely elinfinated, it is believed that, at the very least, fatal large vessel injuries are avoided. The open port insertion method is designed to avoid use of the Veress needle and a sharp pushthrough trocar. II1 addition it seems to maintain a better gas seal around the cannula especially during long laparoscopic p r o c e d u r e s . It also offers an opporttmity to repair the fascial and peritoneal opening during port removal, decreasing further the likelihood of port site herniation.
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Recent advances in endoscopic entry techniques Ternamian A
Figure 2: Open laparoscopyHasson's trocarand cammla. 3. O p t i c a l l a p a r o s c o p i c p r i m a r y e n t r y technique In an attempt to introduce visual guidance to the critical blind first step in laparoscopy and improve entry safety optical entry cannulas were introduced. Endoscopists believe that surgery performed under visual c o n t r o l is i n t e r a c t i v e and h a n d - eye coordination is possible. Added real-time visual feedback not only avoids injury but also recognises mishap when accidents occur. Two disposable models are available, (Endopath~; E t h i c o n , Somerville, N e w Jersey, U S A and Visiport| USSC, Norwalk, Connecticut, USA) these instruments have traded the blind sharp trocar for a hollow trocar with a transparent crystal tip at the distal end. With the laparoscope loaded in the hollow central trocar, the distal crystal transects abdominal tissue layers during insertion. These instruments retain the trocar and cannula spike principle, and the port dynamics remain a p u s h - t h r o u g h m e t h o d . I n s e r t i o n requires a considerable uncontrolled penetration force applied axial to the tissues. The anterior abdonfinal layers tent towards the viscera, and tissue compression by the distal crystal tip renders layer recognition difficult. Progression of the trocar through different anterior abdominal wall layers is recognised only as colour changes.
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4. M i c r o - l a p a r o s c o p y and Optical Veress Patients with previous midline laparoton W incisions are particularly at risk o f developing umbilical adhesions. In these patients a l t e r n a t e e n t r y techniques must be practiced and visually guided entry instruments, at sites other than the umbilicus are used. For h i g h - r i s k cases, a visual Veress e n t r y technique and instruments are preferred. A 1.2 mm diameter semi-rigid fibro-optic minilaparoscope is mounted into a 2.1 nml diameter modified Optical Veress (Karl Storz, Tuttlingen, Germany) which is inserted in the left upper quadrant, at Pahner's point. Subsequent ports are safely inserted under direct visual control. Pahner's point is usually free of adhesions even in patients who have undergone previous surgery 24. Optical insertion allows identification o f an adhesion-free safe primary entry site and eliminates the problems associated with gas insufflation in the wrong place23. Smaller calibre nficro-laparoscopes are also available to visually access the peritoneum in conscious patients for pain mapping and other diagnostic outpatient procedures. Second generation entry technique Task performance studies have identified several important Performance Shaping Factors (PSF) that d e t e r m i n e o u t c o m e . It is believed that the weaknesses in conventional entry techniques and instruments are responsible for most serious entry accidents irrespective of the surgeon's competence and dexterity. Conventional primary entry requires application of considerable axial force to a sharp trocar. The anterior abdominal wall tents towards the viscera, and e n t r y is blind and u n c o n t r o l l e d . T h e compilation of these potentially dangerous PSFs d u r i n g p r i m a r y e n t r y renders accessing less forgiving and sets the stage for inadvertent injury. Second Generation entry systems buffer human error, t h r o u g h system redesign and avoid i n c o r p o r a t i o n o f the i d e n t i f i e d PSE E r r o r recognition is possible when mishaps occur and allow error recovery before the situation evolves to patient harm. This interactive and error-tolerant entry avoids the application of axial force at the port site, requires no sharp or pointed trocar and allows visual and controlled port entry25. When specific PSFs of conventional entry are eliminated
Volume 1 (2) Summer 2001
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Recent advances in endoscopic entry techniques Temanfian A during primary entry, port insertion becomes less dangerous. The endoscopic threaded imaging port ENDOTIP~ is a reusable visual entry cannula that may be used d u r i n g closed or open laparoscopy. It can be applied as a primary or ancillary port, and may be used to p e r f o r m intra or r e t r o - p e r i t o n e a l operations. The entry device consists of a proximal valve and a stainless steel hollow distal cannula. A single thread winds diagonally on its outer surface, which ends distally in a blunt tip. ENDOTIP~ is available in different lengths and diameters for different surgical applications. A reusable retaining ring, telescope stopper, is used to keep the laparoscope from sliding out of focus during insertion. (Figure 3).
Figure 3: Endoscopic Threaded Imaging Port.
ENDOTIP ~
cammla and Telescope stopper. ( Karl Storz, Tuttlingen, Gemmny ) ENDOTIP~ is rotated clockwise with a laparoscope mom~ted, the abdominal ,vall layers move radially on to the outer thread. Entry is h~cremental and controlled. No sharp or Ipointed trocar is required.
A p p l i c a t i o n at t h e p r i m a r y closed entry
port during
An umbilical skin incision is made using a 15 mm surgical blade for the cannula to be freely lowered into the wound. R i b b o n retractors and peanut sponges are used to expose the anterior rectus
Reviews in Gynaecological Practice i
fascia. A small 8 mm rectus fascial incision is then made under direct vision. The Veress needle is inserted through the fascial incision in the usual way. During insufflation, a 0 ~ laparoscope is white balanced and defogged, then the t e l e s c o p e s t o p p e r f o l l o w e d by cannula is mounted. The telescope stopper is locked to keep the laparoscope 2 cm short of the cannula's distal end. The camera is focused to the cannula's tip, and laparoscope is held vertical to the patient's supine abdomen using the surgeon's non-donfinant hand. W h e n insufflation is complete, the Veress is removed, and cannula lowered into the umbilical well with the CO2 stopcock in the closed position. The cannula is rotated clockwise, using the wrist muscles of the donfinant hand while keeping the forearm horizontal to the patient's abdomen, with the surgeon's ~shoulders square in a resting position facing the monitor. The blunt tip engages the anterior rectus fascial window, stretches it radially, and lifts to transpose each tissue layer sequentially onto the cannula's outer thread. The white anterior rectus fascia, red rectus muscle, then pearly white posterior fascia, engage the outer pitch until the yellowish preperitoneal space is reached. (Figure 4).
Figure 4: Closed laparoscopy using ENDOTIP ~ cammla. Abdominal wall layers are seen to stretch radially as cammla advances towards peritoneal cavity. Anterior Rectus Fascia ARF. Rectus Muscle P~I. Posterior Fascia PF. Pre-Peritoneal Space PPS. The laparoscope's intense light traverses the tented peritoneal membrane and C O 2 - filled peritoneal cavity appears gray-blue in colour. Vessels, bowel or adhesions are recognised and inadvertent injury avoided. Further clockwise rotation advances the cannula intra-peritoneally u n d e r direct visual
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Recent advances in endoscopic entry techniques Temamian A control, without requiring trocars and without applying axial penetration force. The cannula is kept perpendicular to the tissues at all times to avoid tunnelling. Application open entry
at t h e p r i m a r y
port during
W h e n inserting the ENDOTIP ~ cannula at the primary port without pre-insufflation, a pair o f anterior rectus fascial absorbable stay-sutures are applied at 3 and 9 o'clock and held on a pair of clamps. Ribbon retractors could be used to better expose the anterior rectus fascia. An 8 mm anterior r e c t u s fascial incision is m a d e using a 15 nani surgical blade. The laparoscope is defogged and camera whitebalanced. The telescope stopper and cannula are mounted, and the telescope stopper locked to keep the laparoscope's e n d 2 cm short of the cannula's distal tip. The camera is focused to the cannula's blunt end and the laparoscope held vertical to the patient's supine abdomen using the surgeon's nondominant hand. T h e ENDOTIP ~ cannula, with the C O 2 stopcock in the open position, is lowered into the umbilical well and rotated clockwise, using the wrist muscles of the dominant hand while keeping the forearm h o r i z o n t a l and shoulders square in a resting position. The cannula's tip engages the anterior fascial window, stretches radially, then lifts to transpose successive tissue layers on the cannula's outer thread. The white anterior rectus fascia, red rectus muscle, then pearly white posterior fascia are pulled up along the outer pitch to the yellowish pre-peritoneum. Due to the intense light and magnification of the laparoscope, bowel or omentum may be observed on the monitor, moving across the transparent p e r i t o n e a l n l e m b r a n e w i t h the r e s p i r a t o r y movements o f the patient. O n c e a peritoneal opening is created, room-air streams through the cannula's open CO2 stopcock, into the virtual p e r i t o n e a l cavity i n t e r p o s e d b e t w e e n the presenting organ's surface and partially separated peritoneal membrane. Clockwise rotation is then stopped, and CO2 insufflation initiated under visual control. (Figure 5). During closed pre-iusufflated laparoscopy, a CO2
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Figure 5: Open laparoscopy using ENDOTIP~) cammla. Anterior Rectus Fascia A F is incised. Clockwise rotation engages cannula's bhmt tip. Muscle M, Posterior Fasda PF is seen to stretch radially on to cammlas outer thread, llqwn Abdomina ! cavity A is altered, room air streams through open C O 2 stopcock. Rotation is stopped and insufflation initiated. Pre-Peritoneal Space PPS, Posterior Fascia PF, Peritoneal Menlbrane PM. filled buffer zone is interposed between the entry device and i n t r a - a b d o m i n a l organs. In o p e n laparoscopy, the visual access cannula encounters abdonfinal contents directly upon peritoneal entry. Tissue sequencing at the port site depends on several factors: mobility and size of the presenting organ, adhesions, intra-peritoneal fluid, and others. Ancillary port entry Ancillary port insertion is an important step during laparoscopic surgery. Various specialised i n s t r u m e n t s are i n t r o d u c e d t h r o u g h these strategically placed ports. The site and method of entry depends on the patient's anatomy, type of procedure performed and surgeon's preference. It is essential that all ancillary ports be inserted under direct visualisation to minimise the risk of inadvertent injury, as the a b d o m e n is already d i s t e n d e d w i t h gas and laparoscopic c a m e r a inserted. Laparoscopic inspection (inferior epigastric) and transillumination (superficial epigastric) identifies the course o f the epigastric vessels. Applying abdominal pressure with the advancing instrumenttip indents the entry-site, while observing the abdonfinal wall parietal anaton W and vasculature. the direction and axis of entry can be altered if vessels are suspected to be along the pathway to
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Recent advances in endoscopic entry techniques Temamian A avoid injury. The inferior epigastric vessels are difficult to identify by abdominal transillunfination, especially in m o r b i d l y obese patients and those w i t h abdominal adhesions. They invariably run lateral to the umbilical ligaments, and are easily identified laparoscopically on either side o f the bladder, medial to the internal inguinal ring. In order to avoid vascular injury, the ancillary ports nmst be inserted lateral to the internal inguinal ring or medial to the umbilical ligaments. The triangular area between these two lines should be avoided if possible. When using E N D O T I P ~ at ancillary ports, only a skin incision and dissection of subcutaneous tissue is needed; aq anterior rectus fascial incision and ancillary telescope are not necessary. As with all ancillary port insertions, they nmst be introduced under direct laparoscopic visual control. To avoid p e r i t o n e a l t u n n e l l i n g , E N D O T I P ~ insertion should remain at right angles to the skin surface until the abdominal cavity is entered. Vessels encountered along the cannula's path move radially out of harm's way and are not transected. The urinary bladder must always be emptied before suprapubic port insertion.
Alternate entry sites Alternate entry sites are considered when umbilical placement of a Veress or Primary port is deemed risky, such as in patients known to have umbilical adhesions. Palmer's point, located 3 cm below the left costal margin in the mid clavicular line is a popular alternative. A naso-gastric tube is inserted to prevent inadvertent gastric injury. The surgeon nmst be particularly careful in patients with portal hypertension, gastric or pancreatic masses or when splenomegaly is suspected26. T h e i n c i d e n c e o f umbilical adhesions are <0.03%, however, it may be as high as 68% in patients with a previous laparotomy, especially in those where a midline surgical scar extends to the umbilical region 27. In high-risk patients, a preliminary parietal umbilical inspection is possible with the ENDOTIP1~ visual cannula, Optical Veress micro-laparoscope, or other optically guided cannulas. Peritoneal adhesions are mapped and additional ports inserted accordingly. Successful peritoneal entry on the first passage o f the Veress n e e d l e t h r o u g h
Reviews in Gynaecological Practice
conventional sites does not exclude the possibility o f umbilical adhesions or s u b s e q u e n t bowel injury upon insertion o f conventional trocars. Patients with known peritoneal adhesions, and a history o f more than one previous laparoscopy, extremely obese patients with a history of previous failed laparoscopy or insufflation and others with special c i r c u m s t a n c e s may be candidates for a l t e r n a t e e n t r y t e c h n i q u e s , w i t h specialised laparoscopic visual entry instruments.
Relevant port removal issues Increasingly, surgeons are realizing the importance o f safe cannula removal to avoid p o r t - s i t e herniation and implantation o f malignant cells along the p o r t tract, f o l l o w i n g o n c o l o g i c a l procedures. The introduction of visual laparoscopic entry systelns allow surgeons to appreciate tissue dynamics at the port-site during insertion and removal of entry devices. It helps determine the integrity of the different tissue layers that establish port competence. Without the ability to visually observe the port tract during insertion and removal o f cannulas, surgeons are unable to identify compronfised entry sites. Consequently, appropriate p r e - e m p t i v e measures are not taken. The published incidence of port herniation is about 0.3% to 1.3% 28,29. The closure of fascial defects is important when predisposing factors exist. Several direct port-site fascial closure instruments are available, however, fascial suturing of laparoscopic entry sites decreases but does not elinfinate incidence of all hernias 28. W h e n inserting sharp pyramidal or cuttingdilating trocars, the instrument transects tissue layers along its path, d i s r u p t i n g the s h u t t e r
Figure 6: During E N D O T I P ~ removal, tissue is seen to regain their natural grid-iron orientation and restore the shutter mechanism at the port site. A s the exit is visual and incremental, tissue entrapment along camntla's tract is avoided. Rectus Musde M. Posterior Fascia PF. Peritoneal membrane P. Anterior Fascia AF.
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Recent advances in endoscopic entry techniques Temanfian A m e c h a n i s m at port site. T h e fascial defect is significantly larger, compared to the non-cutting tips 30. ENDOTIP~ is designed to address port competence concerns, such that the radially displaced tissue layers regain a normal grid-iron orientation and restore their shutter mechanism at port site upon cannula removal31 (Figure 6). When the operation is completed, the stopcock is closed, CO 2 tubing disconnected, laparoscope's end retracted 2 cm into the cannula, telescope stopper locked, and camera focused to E N D O T I P ' S ~ end. The laparoscope is then held perpendicular to the patient's abdomen with the non-dominant hand, and the cannula rotated counter-clockwise with the domiriant hand. As the cannula removal is visual, i n c r e i n e n t a l and c o n t r o l l e d , tissue i n j u r y or entrapment along the cannula's tract is avoided. CO2 is released through an ancillary cannula to avoid spraying body fluids onto the telescope's lens. When the fascial port site is extended to retrieve surgical specimens; fascial sutures are applied to further secure port competence.
Practice P o i n t s * Laparoscopic entry remains a potentially dangerous procedure - closed Veress needle insertion has a complication rate of 2.9 per 1000 cases during laparoscopic surgery * 1st generation techniques depend on insertion of a "spike" mechanism and comprise closed entry, open entry, and optical entry * 2nd generation teclmiques depend on insertion of a "screw" mechanism and comprise the E N D O T I P 1~
* Comparative studies of the available methods are rare and do not show any clear benefits in terms of safety due to the relative infrequency of complications It is important for endoscopists to be versed in more than one safe laparoscopic entry method and be knowledgeable o f different entry techniques, as our patients have different surgical needs. With careful entry selection and meticulous attention to entry technique during primary entry, inadvertent injury can be kept at a minimum.
Conclusion References P r i m a r y e n t r y t e c h n i q u e s have always b e e n considered a critical first step in laparoscopy. The push-through conventional First Generation entry systems apply considerable, u n c o n t r o l l e d axial p e n e t r a t i o n force at p o r t - s i t e to t h r u s t the trajectory blindly towards the peritoneum. Second Generation entry systems are redesigned to buffer inevitable surgical mishaps and r e n d e r laparoscopic primary entry and removal errortolerant. Application of perpendicular penetration force is avoided by realigning direction o f entry from axial to radial. Sharp or pointed trocars are not required, and a visually interactive port creation is possible. Real-time recognition of error when accidents occur, allows timely error recovery, and prevents error from progressing to patient harm. Visual entry systems can improve our understanding of the taxonomy of laparoscopic entry complications and reduce recurring errors. Surgeons can visualise tissue dynamics at port site and appreciate port competence concerns.
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1. Deziel DJ. Avoiding laparoscopic complications, hit Surg 1994; 79: 361-364. 2. Hashizume M, Suginaachi K. Needle and trocar injury during laparoscopic surgery in Japan. Study group of endoscopic surgery in Kyushu, Japan. Surg Endosc 1997; 11:1198-1201. 3. Bogner MS. "Medical Devices and Hulnan Error" in Human Performance in Automated Systems: Current Research and Trends, Mouloua M, and Parasuraman I'Z (eds), Hillsdale, NJ, Lawrence Edbaum, pp 64-67, 1994. 4. Ternamian AM. A Second Generation laparoscopic reusable visual port system. Gynecol Obstet 7: 174180, 2000. 5. Ternanfian A. Laparoscopy without trocars. Sttrg Endosc 1997; 11: 815-818. 6. Nezhat FP,, Silfen SL, Evans D, Nezhat C. Comparison of direct insertion of disposable and standard reusable laparoscopic trocars and previous pneumoperitoneum with Veress needle. Obstet Gynecol 1991; 78: 148-149. 7. Hill DJ, Maher PJ. Direct cannula entry for laparoscopy. J Am Assoc Gynecol Laparosc 1991; 4: 77-79. 8. Byron JW, Markenson G, Miyazawa K. A
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14. 15.
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randomized comparisou of Veress needle and direct trocar insertion for laparoscopy. Surg Gynecol Obstet 1993; 177: 259-262. Soderstrom ILM. Injuries to major vessels during endoscopy.J Am Assoc Gynecol Laparosc 19974; 1: 395-398. Jansen FW, Kapiteyn K, T r i m b o s - K e m p e r T, Hermans JO, Baptist J. Complications o f laparoscopy: a prospective multicentre observational study. BrJ Obstet Gynaecol 1997; 104: 595-600. Smith R.S, Fry WR, Tsoi EK. Gaseless laparoscopy and conventional instruments. The next phase of minimally invasive surgery. Arch Surg 1993; 128: 1102-1107. Turner DJ. A new radially expanding access system for laparoscopic procedures versus conventional cannulas. J Am Assoc Gynecol Laparosc 1996; 3 (4): 609-615. Phillips G[ Garry Ik, Kumar C, Reich H. H o w much gasl.is required for initial insufflation at laparoscopy? Gynaecol Endosc 1999; 8: 369-374. Garry IL. Complications of-laparoscopic entry. Gyna Endosc 1997; 6: 319-329. Sutton Ci A practical approach to diagnostic laparoscopy. In: Sutton C, D i a m o n d M, eds. Endoscopic Surgeryfor Gynaecologists. London: WB. Saunders, 1993: 2-7. Hurd WW, Diamond MP. There's a hole in nay bucket, the cost of disposable instruments. Fertil Steril 1997; 67: 13-5. Chan ACW, Ip M, Koehler A, Crisp B, Tam JS, C h u n g SCS. Is it safe to reuse disposable laparoscopic trocars. Surg Endosc 2000; 14: 10421044. Corson SL, Batzer FIL, Gocial B, Maislin G. Measurement of the force necessary for laparoscopy trocar entry.J Reprod Med 1989; 34: 282-284. Soderstrom RM. Injuries to major blood vessels during endoscopy. J Am Assoc Gynecol Laparosc 1997; 4: 395-398. Loffer FD. Endoscopy in high risk patients. In:
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29. 30.
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Martin DC, ed. Manual o f endoscopy. Santa Fe Springs, CA: Am Assoc Gyne Laparosc;, 1990: 43. McDougall E, Figenshau RS, Clayman IkV, et al. J Laparosc Surg 1994; 4: 6. Mary Ann Liebert, Inc. Publishers. Hasson HM. O p e n laparoscopy. A modified treatment and method of laparoscopy. AnlJ Obstet Gynecol 1971; 110: 886-887. Audebert AJM. The role of microlaparoscopy for safer wall entry: incidence of umbilical adhesions according to past surgical history. Gynaecol Endosc 1999; 8: 363-367. Okeahialanl MG, O ' D o n o v a n PJ, Gupta JK. Microlaparoscopy using an optical Veress needle inserted at Palmer's point. Gynaecol Endosc 1999; 8: 115-116. T e r n a m i a n A. Applications o f E N D O T I P in laparoscopy. Presented at the Annual Meeting Japan Society for Endoscopic Surgery: Tokyo. December 1999. C h a p r o n C, Pierre F, H a r c h a o u i Y, et al. Gastrointestinal injuries during gynaecological laparoscopy. Hmn Repro 1999; 14: 333-337. Childers JM, Brzechffa PR, Sunvit EA. Laparoscopy using the left upper quadrant as the primary trocar site. Gynecol Oncol 1993; 50: 221-225. Mayol J, Garcia-Aguilar J, Ortiz-Oshiro E, DeDiego Carmona JA, Fernandez-Represa JA. W J Surg 1997; 21: 529-533.29. Crist DW, Gadacz T R . Complications o f laparoscopic surgery. Surg Clin N Am 1993; 73: 265. T a r n a y CM, Glass BK, M u n r o MG. Incision Characteristics Associated With Six Laparoscopic T r o c a r - C a n n n l a Systems: A R a n d o m i z e d , Observer-Blinded Comparison. Ain J Obstet Gynecol 1999; 94: 89-93. Temamian A. A second-generation laparoscopic port system. Gynae Endosc; 1999; 8: 397- 401.
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Abstract The most important and potentially dangerous first step in laparoscopy is safe and successful insertion o f the primary cannula. Several entry techniques and instruments are reviewed to illustrate different entry options available to endoscopists. Conventional entry methods use the push-through trocar and cannula design. Considerable axial penetration force is applied to thrust a sharp trajectory into the abdomen. Concern regarding their safety has been expressed when used at primary port, especially in high risk patients and those who have had previous abdominal surgery. Different variations of this blind entry technique attempt to render port insertion safer. However, the push-through principal is retained and surgeons cannot anticipate, avoid or recognise entry injury. Most surgeons agree that visually controlled entry techniques infer added safety and render the process inter[active. Newer optical entry methods allow error recognition when accidents occur and error recovery is POssible before the accident progresses to patient harm. Visually controlled entry systems that require no sharp trocar, apply no axial penetration force, and render this critical first step in laparoscopy more error tolerant. Visual systems allow error analysis and improve our understanding o f laparoscopic entry complications. Ultiinately, endoscopists must be well versed in more than one entry technique, as primary port insertion must be tailored to meet the specific physical and medical needs of each patient. Surgeons must use those entry methods and instruments that they are schooled in and feel safest in their hands. Keywords: laparoscopy, entry technique, access cannula, trocar, ENDOTIP ~, visual cannula
Introduction Endoscopy allows optically guided procedures to be performed within the body, through surgically created temporary ports (laparoscopy, thoracoscopy) or through a natural conduit, without requiring an access wound (hysteroscopy, bronchoscopy). These operations are practiced in most specialties and have b e c o m e a p r e f e r r e d m e t h o d o f diagnosis and treatment of several surgical conditions. Endoscopy is a dynanfic discipline that is quickly evolving and now includes high-resolution imaging technology, allowing frameless stereotactic surgery. The most important and potentially dangerous first step in laparoscopic s u r g e r y is safe and successful insertion of a primary port t.
Division of Gynecologic Endoscopy St. Joseph's Health Centre University of Toronto 77 Truman Rd Toronto, Ontario Canada M2L 2L7 e:maih [email protected]
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Conventional First Generation laparoscopic entry techniques, using the Veress needle and sharp pushthrough trocar and cannula, remain the most commonly used entry method and complications related to their use are well documented2. As more surgical specialties practise laparoscopy, the n u m b e r o f patients w i t h umbilical scars increase. M o r e o v e r , c o n v e n t i o n a l m e t h o d s o f blind umbilical w i m a r y peritoneal entry may not be u n i f o r m l y acceptable. Surgeons p e r f o r m i n g sophisticated operations nmst now be versed in several alternate laparoscopic entry methods and imtrmnents to address evolving safety requirements and patient expectations. P u b l i c a t i o n o f the Institute O f M e d i c i n e comnfittee report on Patient Safety, and the US Congress initiative on prevention of medical error, prompted surgeons and industry to recognise the need for less hazardous laparoscopic entry options especially in high-risk situations. It is believed that 90% o f unintended medical mishaps are human error related3. Therefore, entry methods that can anticipate, avoid or at the v e r y least recognise e r r o r is
Volume 1 (2) Summer 200t
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Recent advances in endoscopic entry techniques Temamian A advocated, where error recovery is possible, before permanent patient harm occurs4. This r e v i e w outlines d i f f e r e n t m e t h o d s o f Primary and Ancillary laparoscopic port insertion and describes recent advances in entry techniques.
4. Micro-laparoscopy Optical Veress direct insertion
Second Generation Entry Technique (Optical Camlula design, Spin Principle) Endoscopic Threaded Imaging Port
Dynamics during port Insertion
ENDOTIP ~
The taxononw of laparoscopic entry injury is best understood when the dynamics at port site are studied and careful error analysis is conducted to unravel the interaction between tissue, instrument and surgeon. Generally, two entry methods are available during laparoscopy. First Generation conventional entry technique, where the push-through spike principle is applied tO place a trocar and cannula design trajectory intraperitoneally, The surgeon palms the access instrument by the d o n l i n a n t tland, and g e n e r a t e s c o n s i d e r a b l e penetration force by the upper arm muscles. This force is applied axially at the port site, for the spike to transect different tissue layers on its way into the abdomen. Several versions, modifications and models have attempted to render this entry system less perilous while maintaining the basic spike and cannula design principle. Second Generation entry technique, uses the spin principle, w h e r e no axial p e n e t r a t i o n force is applied; an optically guided cannula pulls tissues up along an outside thread. Tissue layers are radially parted instead of being transected by a sharp or bevelled central trocar. A laparoscope, mounted into the cannula, replaces the trocar, to offer visually controlled port placement5.
Endoscopic entry techniques First generation entry technique (Trocar & cammla design, spike principle) .
Closed entry pre-insufflation direct insertion radially expanding trocar high pressure insufflation
2.
Open Hasson's entry direct insertion
3.
Optical entry pre-insufflation
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pre-insuftlation direct insertion extra peritoneal insufflation
First generation entry technique The primary port is the first access site through which a camera, lens and light is introduced. Its insertion is a critical first step during laparoscopy when most serious injuries occur. Veress or trocar placement is particularly perilous, as considerable uncontrolled axial force is applied blindly to sharp instruments. Moreover, all practitioners agree that subsequent ancillary ports must be inserted under direct vision, as it is a c c e p t e d that visually controlled entry is safer. During 'Closed' entry laparoscopy, most surgeons insufflate before insertion o f the primary port. However, some endoscopists prefer alternate closed entry methods. A few small studies suggest that direct primary trocar insertion before insufflation may cause fewer entry complications6-8. Direct trocar insertion advocates r e c o m m e n d elevation o f the anterior abdonfinal wall while inserting the sharp pr!mary trocar directly and blindly towards the peritoneal cavity. The COz gas stopcock is kept open, for the negative intraabdominal pressure to be relieved as the vented instrument tip enters the potential peritoneal space. It is suggested that the viscera fall off its parietal apposition prior to contact with the advancing sharp trocar. (Figure 1) Published data generally do not support the conclusion that 'Direct' entry is any safer than conventional 'Closed' entry. Studies recommending this entry method are too small to make reliable statistically valid observations. Ma~W surgeons find insertion of a sharp trocar blindly into an noninsufflated abdomen potentially hazardous and indefensible. Bowel injury has been reported as a c o n s e q u e n c e o f the 'Direct' entry technique. Certainly larger trials are necessary to better understand this blind insertion method.
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Figure 1: Conventional sharp pyramidal trocarand cammla. Available e v i d e n c e d e m o n s t r a t e that vascular injuries are seven times more likely to be caused by either the primary or ancillary trocar placement than by the Veress n e e d l e 9. In a n a t i o n w i d e prospective m u l t i c e n t r i c D u t c h study, Jansen reviewed 25,764 laparoscopies. Five complications w e r e caused by the Veress n e e d l e and 68 by insertion of the trocar t0 Gasless l a p a r o s c o p y is a n o t h e r m e t h o d o f endoscopy where insufflation is not utilised. The primary port site is dissected down to peritoneum, special abdominal wall lifters, attached to the operating table are required. T h e a b d o m e n is tented to create a peritoneal working compartment where different trocars are inserted directly. This method does not seem to offer as uniform a displacement o f viscera as p n e u m o - p e r i t o n e u m does. It allows use o f conventional laparoton W i n s t r u m e n t s and r e d u c e s the l a p a r o s c o p i c operation's learning curve tl. Several abdominal lifting instruments are available, some are intrusive and most surgeons prefer the c o n v e n t i o n a l insuttlated method. Radially expanding disposable trocar systems use an expanding outer sleeve that fits over a Veress needle. The abdomen is first insufflated, then the Veress needle removed. A trocar is then inserted into the sleeve that gradually expands to accommodate the trocar's diameter. The central spike is then replaced with a laparoscope t2.
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High pressure CO2 gas insufflation technique is a variation on the classic closed insertion method where insufflation to an intra-peritoneal pressure of 25 m m H g or higher is attained using a Veress needle. This splints better the anterior abdominal wall against axial penetration force and interposes a larger C O 2 gas cushion between the advancing t r a j e c t o r y and great vessels or a b d o m i n a l viscera. Bowel adherent to parietal abdominal wall remains susceptible to injury, as insertion is blind. Once a cannula is placed and correct insertion verified intra-peritoneal pressure is lowered to 10-15 m m H g a3-ts. Although multiple-use and single-use trocars are available, there is a movement back to reusable instruments. Environmentally conscious and fiscally strained health care systems generally advocate purchase of reusables 16. Moreover, nmltiple use of a single-use-designated instrument, especially a trocar is generally not recommendedaL Unfortunately, surgeons have less say in theatre p u r c h a s i n g decisions and are only called to defend outcome when mishaps occur. Most publications extol the virtues o f sharp trocars; it is generally accepted that they require less penetration force to traverse anterior abdominal layers, c o m p a r e d w i t h a less sharp trocart8. Adnfittedly, the extreme sharpness o f disposable e n t r y i n s t r u m e n t s may make i n s e r t i o n less controlled, where the risk of inadvertent bowel or vessel injury is higher. In some series, the risk of bowel injury with disposable trocars is about three times that previously reported for reusable trocars. T h e m a j o r i t y o f disposable trocars w i t h an a u t o m a t i c a l l y e x t e n d i n g 'safety' shield w e r e designed to decrease risk o f inadvertent injury. However, the US Food and Drug Administration n o w requires all d e v i c e m a n u f a c t u r e r s and distributors of shielded access cammlas to eliminate claims o f added 'safety q9. As visualisation o f the primary port is impossible, except w h e n using optical entry cannulas, it is advisable to always inspect the inner aspect of the primary entry site, through one o f the ancillary ports at the end of each laparoscopy. 1. C l o s e d l a p a r o s c o p i c primary entry technique Inspection o f the supine non-draped abdomen, n o t i n g o f p r e v i o u s surgical scars, a b d o m i n a l palpation and identification o f bony landmarks
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Recent advances in endoscopic entry techniques Temamian A must precede every laparoscopic primary port insertion. An umbilical skin incision is made, followed by insertion o f the Veress needle to distend the peritoneal cavity with C O 2 gas. This braces the abdominal wall to offer counter pressure against the considerable axial penetration force applied. The gas cushion, interposed b e t w e e n an advancing sharp trocar and abdominal viscera may avoid unintended injury. In addition, a gas filled spacious inert cavity allows unobstructed visualisation o f organs during surgery. T h e spring-loaded needle is first tested and stopcock kept open to allow room air to stream into the vacuum-sealed peritoneal cavity as soon as the peritoneal membrane is penetrated. The Veress needle, held at the hub by the dominant hand, is vertically inserted towards the peritoneum. Generally i w o distinct "pops" are felt as the needle passe s first through-anterior rectus fascia, then through posterior fascia and peritoneum. Once a second pop is felt, the needle is directed towards the pelvis 20- W h e n insertion is intraumbilical, only one pop is felt. D e t e r m i n i n g c o r r e c t p l a c e m e n t p r i o r to insuffiation is very important, as failure to achieve and maintain p n e u m o p e r i t o n e u m is a c o m m o n cause o f procedural failure. It is important to closely follow intra-peritoneal pressure changes during insufflation and keep the flow rate initially at less than one litre per minute. Inadvertent improper Veress needle placement and a high flow rate may lead to serious complications. O n c e correct needle placement is verified, the flow rate may be increased. The maximal accepted intraperitoneal pressure is 15 mmHg. It is accepted that obesity does not adversely affect insuffiated C O 2 volume for a given intra abdominal pressure. The actual intra-abdominal volume is a finite value, and 94% of this capacity is achieved at an abdominal pressure of 15 mmHg21. W h e n higher pressures are recorded d u r i n g insufflation, the position of the needle is changed by gently drawing out or moving it sideways, to dislodge the tip that may be against a viscus. Alternatively, the a b d o m i n a l wall c o u l d be manually elevated with similar results. Injecting a few millilitres of saline could also be tried. It is important to make sure that the patient is well anaesthetised as " b u c k i n g " could give similar
Reviews in Gynaecological Practice
readings. When all fails, it is better to remove the Veress, inspect for malfunction and then reinsert it anew.
Manual abdominal palpation remains a preferred method o f determining degree o f distention, as measurement o f total volume o f instilled gas is unreliable. Having attained adequate insufflation, the Veress needle is removed and the conventional trocar and cannula is inserted towards the distended peritoneal cavity blindly. This basic entry principal has not changed nmch since its inception. 2. O p e n laparoscopic p r i m a r y entry technique In 1971 H. Hasson first introduced a primary port insertion m e t h o d w h e r e a Veress needle and p r e - i n s u f f l a t i o n is n o t r e q u i r e d . A g e n e r o u s u m b i l i c a l skin i n c i s i o n is made and the subcutaneous layer dissected to expose the anterior rectus fascia. S-shaped retractors facilitate exposure. Two Kocher clamps hold the fascia and stay sutures are placed at 3 and 9 o'clock. The anterior fascia is incised between the two sutures using a curved long Mayo scissors and the exposed peritoneum is entered using a blunt snap 22. A finger is then inserted into the peritoneal w i n d o w to ensure absence o f adhesions. T h e Hasson trocar and cannula is then introduced and secured to the fascia using the stay sutures. A cone shaped obturator further discourages gas leakage around the cannula's stem. (Figure 2). Several variations on this intuitive method have been described, h o w e v e r the access principle remains the same and an increasing number o f surgeons prefer this m e t h o d , especially w h e n inserting ports in patients who have had previous abdominal surgery and parietal adhesions are suspected. Although the possibility o f access injury to adherent viscera at the immediate port site is not entirely elinfinated, it is believed that, at the very least, fatal large vessel injuries are avoided. The open port insertion method is designed to avoid use of the Veress needle and a sharp pushthrough trocar. II1 addition it seems to maintain a better gas seal around the cannula especially during long laparoscopic p r o c e d u r e s . It also offers an opporttmity to repair the fascial and peritoneal opening during port removal, decreasing further the likelihood of port site herniation.
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Recent advances in endoscopic entry techniques Ternamian A
Figure 2: Open laparoscopyHasson's trocarand cammla. 3. O p t i c a l l a p a r o s c o p i c p r i m a r y e n t r y technique In an attempt to introduce visual guidance to the critical blind first step in laparoscopy and improve entry safety optical entry cannulas were introduced. Endoscopists believe that surgery performed under visual c o n t r o l is i n t e r a c t i v e and h a n d - eye coordination is possible. Added real-time visual feedback not only avoids injury but also recognises mishap when accidents occur. Two disposable models are available, (Endopath~; E t h i c o n , Somerville, N e w Jersey, U S A and Visiport| USSC, Norwalk, Connecticut, USA) these instruments have traded the blind sharp trocar for a hollow trocar with a transparent crystal tip at the distal end. With the laparoscope loaded in the hollow central trocar, the distal crystal transects abdominal tissue layers during insertion. These instruments retain the trocar and cannula spike principle, and the port dynamics remain a p u s h - t h r o u g h m e t h o d . I n s e r t i o n requires a considerable uncontrolled penetration force applied axial to the tissues. The anterior abdonfinal layers tent towards the viscera, and tissue compression by the distal crystal tip renders layer recognition difficult. Progression of the trocar through different anterior abdominal wall layers is recognised only as colour changes.
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4. M i c r o - l a p a r o s c o p y and Optical Veress Patients with previous midline laparoton W incisions are particularly at risk o f developing umbilical adhesions. In these patients a l t e r n a t e e n t r y techniques must be practiced and visually guided entry instruments, at sites other than the umbilicus are used. For h i g h - r i s k cases, a visual Veress e n t r y technique and instruments are preferred. A 1.2 mm diameter semi-rigid fibro-optic minilaparoscope is mounted into a 2.1 nml diameter modified Optical Veress (Karl Storz, Tuttlingen, Germany) which is inserted in the left upper quadrant, at Pahner's point. Subsequent ports are safely inserted under direct visual control. Pahner's point is usually free of adhesions even in patients who have undergone previous surgery 24. Optical insertion allows identification o f an adhesion-free safe primary entry site and eliminates the problems associated with gas insufflation in the wrong place23. Smaller calibre nficro-laparoscopes are also available to visually access the peritoneum in conscious patients for pain mapping and other diagnostic outpatient procedures. Second generation entry technique Task performance studies have identified several important Performance Shaping Factors (PSF) that d e t e r m i n e o u t c o m e . It is believed that the weaknesses in conventional entry techniques and instruments are responsible for most serious entry accidents irrespective of the surgeon's competence and dexterity. Conventional primary entry requires application of considerable axial force to a sharp trocar. The anterior abdominal wall tents towards the viscera, and e n t r y is blind and u n c o n t r o l l e d . T h e compilation of these potentially dangerous PSFs d u r i n g p r i m a r y e n t r y renders accessing less forgiving and sets the stage for inadvertent injury. Second Generation entry systems buffer human error, t h r o u g h system redesign and avoid i n c o r p o r a t i o n o f the i d e n t i f i e d PSE E r r o r recognition is possible when mishaps occur and allow error recovery before the situation evolves to patient harm. This interactive and error-tolerant entry avoids the application of axial force at the port site, requires no sharp or pointed trocar and allows visual and controlled port entry25. When specific PSFs of conventional entry are eliminated
Volume 1 (2) Summer 2001
Reviews in Gynaecological Practice
Recent advances in endoscopic entry techniques Temanfian A during primary entry, port insertion becomes less dangerous. The endoscopic threaded imaging port ENDOTIP~ is a reusable visual entry cannula that may be used d u r i n g closed or open laparoscopy. It can be applied as a primary or ancillary port, and may be used to p e r f o r m intra or r e t r o - p e r i t o n e a l operations. The entry device consists of a proximal valve and a stainless steel hollow distal cannula. A single thread winds diagonally on its outer surface, which ends distally in a blunt tip. ENDOTIP~ is available in different lengths and diameters for different surgical applications. A reusable retaining ring, telescope stopper, is used to keep the laparoscope from sliding out of focus during insertion. (Figure 3).
Figure 3: Endoscopic Threaded Imaging Port.
ENDOTIP ~
cammla and Telescope stopper. ( Karl Storz, Tuttlingen, Gemmny ) ENDOTIP~ is rotated clockwise with a laparoscope mom~ted, the abdominal ,vall layers move radially on to the outer thread. Entry is h~cremental and controlled. No sharp or Ipointed trocar is required.
A p p l i c a t i o n at t h e p r i m a r y closed entry
port during
An umbilical skin incision is made using a 15 mm surgical blade for the cannula to be freely lowered into the wound. R i b b o n retractors and peanut sponges are used to expose the anterior rectus
Reviews in Gynaecological Practice i
fascia. A small 8 mm rectus fascial incision is then made under direct vision. The Veress needle is inserted through the fascial incision in the usual way. During insufflation, a 0 ~ laparoscope is white balanced and defogged, then the t e l e s c o p e s t o p p e r f o l l o w e d by cannula is mounted. The telescope stopper is locked to keep the laparoscope 2 cm short of the cannula's distal end. The camera is focused to the cannula's tip, and laparoscope is held vertical to the patient's supine abdomen using the surgeon's non-donfinant hand. W h e n insufflation is complete, the Veress is removed, and cannula lowered into the umbilical well with the CO2 stopcock in the closed position. The cannula is rotated clockwise, using the wrist muscles of the donfinant hand while keeping the forearm horizontal to the patient's abdomen, with the surgeon's ~shoulders square in a resting position facing the monitor. The blunt tip engages the anterior rectus fascial window, stretches it radially, and lifts to transpose each tissue layer sequentially onto the cannula's outer thread. The white anterior rectus fascia, red rectus muscle, then pearly white posterior fascia, engage the outer pitch until the yellowish preperitoneal space is reached. (Figure 4).
Figure 4: Closed laparoscopy using ENDOTIP ~ cammla. Abdominal wall layers are seen to stretch radially as cammla advances towards peritoneal cavity. Anterior Rectus Fascia ARF. Rectus Muscle P~I. Posterior Fascia PF. Pre-Peritoneal Space PPS. The laparoscope's intense light traverses the tented peritoneal membrane and C O 2 - filled peritoneal cavity appears gray-blue in colour. Vessels, bowel or adhesions are recognised and inadvertent injury avoided. Further clockwise rotation advances the cannula intra-peritoneally u n d e r direct visual
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Recent advances in endoscopic entry techniques Temamian A control, without requiring trocars and without applying axial penetration force. The cannula is kept perpendicular to the tissues at all times to avoid tunnelling. Application open entry
at t h e p r i m a r y
port during
W h e n inserting the ENDOTIP ~ cannula at the primary port without pre-insufflation, a pair o f anterior rectus fascial absorbable stay-sutures are applied at 3 and 9 o'clock and held on a pair of clamps. Ribbon retractors could be used to better expose the anterior rectus fascia. An 8 mm anterior r e c t u s fascial incision is m a d e using a 15 nani surgical blade. The laparoscope is defogged and camera whitebalanced. The telescope stopper and cannula are mounted, and the telescope stopper locked to keep the laparoscope's e n d 2 cm short of the cannula's distal tip. The camera is focused to the cannula's blunt end and the laparoscope held vertical to the patient's supine abdomen using the surgeon's nondominant hand. T h e ENDOTIP ~ cannula, with the C O 2 stopcock in the open position, is lowered into the umbilical well and rotated clockwise, using the wrist muscles of the dominant hand while keeping the forearm h o r i z o n t a l and shoulders square in a resting position. The cannula's tip engages the anterior fascial window, stretches radially, then lifts to transpose successive tissue layers on the cannula's outer thread. The white anterior rectus fascia, red rectus muscle, then pearly white posterior fascia are pulled up along the outer pitch to the yellowish pre-peritoneum. Due to the intense light and magnification of the laparoscope, bowel or omentum may be observed on the monitor, moving across the transparent p e r i t o n e a l n l e m b r a n e w i t h the r e s p i r a t o r y movements o f the patient. O n c e a peritoneal opening is created, room-air streams through the cannula's open CO2 stopcock, into the virtual p e r i t o n e a l cavity i n t e r p o s e d b e t w e e n the presenting organ's surface and partially separated peritoneal membrane. Clockwise rotation is then stopped, and CO2 insufflation initiated under visual control. (Figure 5). During closed pre-iusufflated laparoscopy, a CO2
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Figure 5: Open laparoscopy using ENDOTIP~) cammla. Anterior Rectus Fascia A F is incised. Clockwise rotation engages cannula's bhmt tip. Muscle M, Posterior Fasda PF is seen to stretch radially on to cammlas outer thread, llqwn Abdomina ! cavity A is altered, room air streams through open C O 2 stopcock. Rotation is stopped and insufflation initiated. Pre-Peritoneal Space PPS, Posterior Fascia PF, Peritoneal Menlbrane PM. filled buffer zone is interposed between the entry device and i n t r a - a b d o m i n a l organs. In o p e n laparoscopy, the visual access cannula encounters abdonfinal contents directly upon peritoneal entry. Tissue sequencing at the port site depends on several factors: mobility and size of the presenting organ, adhesions, intra-peritoneal fluid, and others. Ancillary port entry Ancillary port insertion is an important step during laparoscopic surgery. Various specialised i n s t r u m e n t s are i n t r o d u c e d t h r o u g h these strategically placed ports. The site and method of entry depends on the patient's anatomy, type of procedure performed and surgeon's preference. It is essential that all ancillary ports be inserted under direct visualisation to minimise the risk of inadvertent injury, as the a b d o m e n is already d i s t e n d e d w i t h gas and laparoscopic c a m e r a inserted. Laparoscopic inspection (inferior epigastric) and transillumination (superficial epigastric) identifies the course o f the epigastric vessels. Applying abdominal pressure with the advancing instrumenttip indents the entry-site, while observing the abdonfinal wall parietal anaton W and vasculature. the direction and axis of entry can be altered if vessels are suspected to be along the pathway to
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Recent advances in endoscopic entry techniques Temamian A avoid injury. The inferior epigastric vessels are difficult to identify by abdominal transillunfination, especially in m o r b i d l y obese patients and those w i t h abdominal adhesions. They invariably run lateral to the umbilical ligaments, and are easily identified laparoscopically on either side o f the bladder, medial to the internal inguinal ring. In order to avoid vascular injury, the ancillary ports nmst be inserted lateral to the internal inguinal ring or medial to the umbilical ligaments. The triangular area between these two lines should be avoided if possible. When using E N D O T I P ~ at ancillary ports, only a skin incision and dissection of subcutaneous tissue is needed; aq anterior rectus fascial incision and ancillary telescope are not necessary. As with all ancillary port insertions, they nmst be introduced under direct laparoscopic visual control. To avoid p e r i t o n e a l t u n n e l l i n g , E N D O T I P ~ insertion should remain at right angles to the skin surface until the abdominal cavity is entered. Vessels encountered along the cannula's path move radially out of harm's way and are not transected. The urinary bladder must always be emptied before suprapubic port insertion.
Alternate entry sites Alternate entry sites are considered when umbilical placement of a Veress or Primary port is deemed risky, such as in patients known to have umbilical adhesions. Palmer's point, located 3 cm below the left costal margin in the mid clavicular line is a popular alternative. A naso-gastric tube is inserted to prevent inadvertent gastric injury. The surgeon nmst be particularly careful in patients with portal hypertension, gastric or pancreatic masses or when splenomegaly is suspected26. T h e i n c i d e n c e o f umbilical adhesions are <0.03%, however, it may be as high as 68% in patients with a previous laparotomy, especially in those where a midline surgical scar extends to the umbilical region 27. In high-risk patients, a preliminary parietal umbilical inspection is possible with the ENDOTIP1~ visual cannula, Optical Veress micro-laparoscope, or other optically guided cannulas. Peritoneal adhesions are mapped and additional ports inserted accordingly. Successful peritoneal entry on the first passage o f the Veress n e e d l e t h r o u g h
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conventional sites does not exclude the possibility o f umbilical adhesions or s u b s e q u e n t bowel injury upon insertion o f conventional trocars. Patients with known peritoneal adhesions, and a history o f more than one previous laparoscopy, extremely obese patients with a history of previous failed laparoscopy or insufflation and others with special c i r c u m s t a n c e s may be candidates for a l t e r n a t e e n t r y t e c h n i q u e s , w i t h specialised laparoscopic visual entry instruments.
Relevant port removal issues Increasingly, surgeons are realizing the importance o f safe cannula removal to avoid p o r t - s i t e herniation and implantation o f malignant cells along the p o r t tract, f o l l o w i n g o n c o l o g i c a l procedures. The introduction of visual laparoscopic entry systelns allow surgeons to appreciate tissue dynamics at the port-site during insertion and removal of entry devices. It helps determine the integrity of the different tissue layers that establish port competence. Without the ability to visually observe the port tract during insertion and removal o f cannulas, surgeons are unable to identify compronfised entry sites. Consequently, appropriate p r e - e m p t i v e measures are not taken. The published incidence of port herniation is about 0.3% to 1.3% 28,29. The closure of fascial defects is important when predisposing factors exist. Several direct port-site fascial closure instruments are available, however, fascial suturing of laparoscopic entry sites decreases but does not elinfinate incidence of all hernias 28. W h e n inserting sharp pyramidal or cuttingdilating trocars, the instrument transects tissue layers along its path, d i s r u p t i n g the s h u t t e r
Figure 6: During E N D O T I P ~ removal, tissue is seen to regain their natural grid-iron orientation and restore the shutter mechanism at the port site. A s the exit is visual and incremental, tissue entrapment along camntla's tract is avoided. Rectus Musde M. Posterior Fascia PF. Peritoneal membrane P. Anterior Fascia AF.
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Recent advances in endoscopic entry techniques Temanfian A m e c h a n i s m at port site. T h e fascial defect is significantly larger, compared to the non-cutting tips 30. ENDOTIP~ is designed to address port competence concerns, such that the radially displaced tissue layers regain a normal grid-iron orientation and restore their shutter mechanism at port site upon cannula removal31 (Figure 6). When the operation is completed, the stopcock is closed, CO 2 tubing disconnected, laparoscope's end retracted 2 cm into the cannula, telescope stopper locked, and camera focused to E N D O T I P ' S ~ end. The laparoscope is then held perpendicular to the patient's abdomen with the non-dominant hand, and the cannula rotated counter-clockwise with the domiriant hand. As the cannula removal is visual, i n c r e i n e n t a l and c o n t r o l l e d , tissue i n j u r y or entrapment along the cannula's tract is avoided. CO2 is released through an ancillary cannula to avoid spraying body fluids onto the telescope's lens. When the fascial port site is extended to retrieve surgical specimens; fascial sutures are applied to further secure port competence.
Practice P o i n t s * Laparoscopic entry remains a potentially dangerous procedure - closed Veress needle insertion has a complication rate of 2.9 per 1000 cases during laparoscopic surgery * 1st generation techniques depend on insertion of a "spike" mechanism and comprise closed entry, open entry, and optical entry * 2nd generation teclmiques depend on insertion of a "screw" mechanism and comprise the E N D O T I P 1~
* Comparative studies of the available methods are rare and do not show any clear benefits in terms of safety due to the relative infrequency of complications It is important for endoscopists to be versed in more than one safe laparoscopic entry method and be knowledgeable o f different entry techniques, as our patients have different surgical needs. With careful entry selection and meticulous attention to entry technique during primary entry, inadvertent injury can be kept at a minimum.
Conclusion References P r i m a r y e n t r y t e c h n i q u e s have always b e e n considered a critical first step in laparoscopy. The push-through conventional First Generation entry systems apply considerable, u n c o n t r o l l e d axial p e n e t r a t i o n force at p o r t - s i t e to t h r u s t the trajectory blindly towards the peritoneum. Second Generation entry systems are redesigned to buffer inevitable surgical mishaps and r e n d e r laparoscopic primary entry and removal errortolerant. Application of perpendicular penetration force is avoided by realigning direction o f entry from axial to radial. Sharp or pointed trocars are not required, and a visually interactive port creation is possible. Real-time recognition of error when accidents occur, allows timely error recovery, and prevents error from progressing to patient harm. Visual entry systems can improve our understanding of the taxonomy of laparoscopic entry complications and reduce recurring errors. Surgeons can visualise tissue dynamics at port site and appreciate port competence concerns.
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