isit really minimally invasive??
Hosam Mohamad Hamza, MD
Lecturer of General Surgery and GI Endoscopy
Minia Faculty of Medicine
Minimally Invasive Surgery
A philosophical approach to surgery in which the trauma of surgical
access is minimized without compromising the quality of the surgical
•Although the term is relatively recent, the history of MIS is not new.
•The use of tube and speculum in medicine dates from the earliest days of
civilization in ancient Greece.
•Laparoscopy (LAP) that is considered the newest and most popular variety is,
in fact, the oldest (primitive laparoscopy, placing a cystoscope within an inflated
abdomen, was first performed by Kelling in 1901).
Historical background, contd:
•The explosion of video-assisted surgery in the past 30 years changed
our understanding of surgical anatomy and reshaped surgical practice.
•Lap-guided gall stone clearance was 1st performed in animal model
by Frimberger and associates in Germany in 1971.
•In 1987, Mouret (Lyon, France) was the 1st
surgeon to perform
cholecystectomy in human using standard laparoscopic equipment,
then, great advances follow in lap. techniques in various specilalities.
•The motivation to develop surgical robots was to overcome the
limitations related to the technical and mechanical nature of lap.
- Loss of tactile feedback.
- Loss natural hand-eye coordination.
- Fulcrum effect.
- Amplification of physiologic tremors of the surgeon.
Historical background, contd:
•RoboDoc (a robotic system designed to drill the femur shaft in hip
replacement) was the 1st
computer-assisted surgical robot approved
by the FDA in the late 1980's.
•Advances then continue till introduction of the Automated Endoscopic
System for Optimal Positioning (AESOP), a robotic arm controlled by
the surgeon's voice commands and Da Vinci and
Zeus surgical systems.
•IN THE FUTUREIN THE FUTURE, equipped nanorobots introduced through BVs and
guided by a human surgeon may be capable of performing precise
intracellular surgeries beyond the capabilities of the human / robotic
1.LAP is inspection of the peritoneal cavity with a telescope introduced
through the abd wall after creation of pneumoperitoneum.
2.Lap. surgery is the execution of an established surgical procedure by
remote manipulations within the closed abd cavity using LAP.
Advantages (rationale for minimally invasive surgery):
☞ Minimal invasion
1.Minimization of body invasion & parietal trauma (avoiding large access
2.Significant ↓ of postoperative pain.
3.Significant ↓ of perioperative morbidity:
• ↓ cardiopulmonary complications.
• ↓ postoperative ileus.
• ↓ postoperative adhesions.
• ↓ wound complications (e.g. infection, dehiscence, …. ).
• ↓ cosmetic insult.
4. ↑ Speed of recovery.
5. Minimization of the stress response to surgery (decreased levels of
catecholamines, cortisol, glucose and other acute phase reactants
compared with laparotomy).
6. Minimization of surgery-induced immunosuppression (preserved
cell mediated immunity compared with laparotomy) that may have
important implications esp in cancer surgery.
☞ Visual enhancement: by the magnifying effect of the telescope.
☞ ↓ incidence of infection:
The greatly ↓ contact with patient's blood and body fluids ↓
of viral diseases for both patient and surgeon.
minimized by appropriate training and
Necessity to purchase & maintain expensive high technology
•Necessity for insufflation (effects of pneumoperitoneum).
•Necessity to access space via needle & trocars (risk of visceral injury).
•Haemostasis can be difficult to achieve.
•Intact organ retrieval, particularly if tumourous, may be seriously limited.
•Requires more technical expertise and long time, at least initially.
•Loss of touch sensation & tactile feedback.
•Loss of 3-D visualization (images of current camera systems are 2-D).
•Loss of eye/hand co-ordination.
•Limited degrees of motion.
•Amplification of the surgeon's physiologic tremors through the length of
PHYSIOLOGICAL CHANGES WITH
PHYSIOLOGICAL CHANGES WITH
Inadvertent Pneumo-preperitoneumInadvertent Pneumo-preperitoneum
•2% of cases.
1. Drop or aspiration test.
2. palpation of crepitus under the skin.
3. typical spider-web appearance after inserting the 1st
(further stripping of peritoneum by the telescope tip is to be avoided)
1.if detected early (before cannula insertion):
* allow gas to escape.
* then re-introduce needle through the same or another site.•g
•If detected after cannula insertion:
* withdraw cannula & telescope.
* allow gas to escape.
* re-introduce needle or use “open technique”.
PHYSIOLOGICAL CHANGES WITHPHYSIOLOGICAL CHANGES WITH
•The singular feature of laparoscopy is the need to lift the abdominal wall
from the abdominal organs.
IDEAL GAS FOR INSUFFLATIONIDEAL GAS FOR INSUFFLATION
3.Non explosive (doesn’t support combustion).
5.Limited systemic absorption across peritoneum.
6.Limited systemic effects if absorbed.
7.Rapid excretion if absorbed.
8.High solubility in blood.
Gasless laparoscopy.Pneumoperitoneum or
• Throughout the early 20th
century, pneumoperitoneum was achieved by
inflating the abd cavity with air using sphygmomanometer bulb.
• CO2 and N2O were then used.
Advantages 1. Highly soluble.
2. Better analgesia.
3. ↓ intraoperative end-tidal CO2.
4. Insignificant acid/base imbalance.
1. More soluble.
2. Less expensive.
3. Doesn’t support combustion.
4. Readily available.
Disadvant. 1. Possibility of combustion.
2. Lap. cancer surgery (CAUTIONCAUTION).
3. Safety in pregnancy has yet to be
2. Hypercarbia: Sympathetic ++ :
Tachycardia , Arrhythmias , HTN
3.Stored CO2 may take hours to
Physiologic effects of CO2 pneumoperitoneum can be divided into:
(a) local effects.
(b) systemic effects.
A. LOCAL (abdominal) EFFECTS OF PNEUMOPERITONEUM:
1.Peritoneal distention: and postoperative pain.
•A rapid stretch of peritoneum often causes a vagovagal response with
bradycardia (commonest cardiac dysrhythmias with laparoscopy) and,
•Appropriate management is:
_ desufflation of the abdomen
_ vagolytic agents (e.g., atropine)
_ adequate volume replacement.
1.Peritoneum is a 37 °C potential space covered by a wet film of fluid.
2.The currently used CO2 is instilled at 21°Cat 21°C and extremely dryextremely dry.
3.Absence of water in a gas going into a wetted cavity causes tissue
desiccation and damage that precede adhesion formation.
B. SYSTEMIC EFFECTS OF PNEUMOPERITONEUM:
Absence of water in a gas going into a wetted cavity causes
2. Respiratory effects:
a. Respiratory acidosis and hypercarbia:
•Insufflation → CO2 is rapidly absorbed → hydration to carbonic acid in RBCs
(buffering capacity of Hb).
•Respiratory acidosis is prevented by body buffers (largest reserve lies in bone
that absorb up to 120 L of CO2).
•Once the body buffers are saturated, acidosis rapidly develops.
•Mild respiratory acidosis is probably an insignificant problem.
•More severe respiratory acidosis= cardiac arrhythmias has been reported.
•Hypercarbia= tachycardia & ↑systemic vascular resistance=↑BP& ↑myocardial O2
•In patients with normal respiratory function; anesthesiologist shouldIn patients with normal respiratory function; anesthesiologist should ↑↑ thethe
ventilatory rate on the ventilator (within limits).ventilatory rate on the ventilator (within limits).
•In some situations, it is advisable to reduce the IAP (or even evacuate theIn some situations, it is advisable to reduce the IAP (or even evacuate the
pneumoperitoneum) to allow time for the anesthesiologist to adjust forpneumoperitoneum) to allow time for the anesthesiologist to adjust for
b. increased intrathoracic pressure:
The direct effect of pneumoperitoneum leads to:
•↑ intrathoracic pressure.
•↑ pressure across the chest wall.
•↑ likelihood of pulmonary barotrauma.
c. pneumothorax: (esp in lap. surgery at the GO junction)
1. gas tracking:
_along the tissue planes & potential channels
_along surgically traumatized pleura
_along undetected diaphragmatic hernia
2. Barotrauma (rupture of an emphysematous bleb).
Unexplained Occurrence Of One Or More of the following should
alert us to the possibility of pneumothorax:
1* sudden ↓ oxygen satura-tion 2*↓ motion of hemidiaphragm
3* ↓ air entry on auscultation 4* ↑ airway pressure
c. pneumothorax, contd :
1. DON’T RUSH for an ICT.
2. PEEP (if NO pulmonary barotrauma).
3. Stop gas.
5. Tube drainage (if spontaneous resolution does not occur for 1
hour of exsufflation).
d. Endobronchial intubation:
•Due to upward tracheal displacement during high P peritoneal insufflation.
•If occurs→ bronchospasm, hypoxia and atelectasis.
•Position of the ETT should always be checked intra-operatively.Position of the ETT should always be checked intra-operatively.
e. Aspiration of gastric contents: due to:
1* increased intra-abdominal pressure
2* change in posture
3* manipulation of the stomach
•Risk is reduced by appropriate NG and ET tube placementNG and ET tube placement.
f. Gas embolism:
•Rare but SERIOUSSERIOUS (potentially lethal).
•Causes my include:
1* inadvertent intravascular gas in-j. through a misplaced Veress
2* forcing of gas into a vein splinted open
3* extensive argon beam use in LH (argon gas embolism)
• Clinical effects:
Pulmonary gas embolism Cerebral gas embolism
-Slow infusionSlow infusion of CO2 is readily absorbed
across the capillary - alveolar membrane.
-High ratesHigh rates→ bronchospasm &
-Large infusion rates ≥ 3 ml/kgrates ≥ 3 ml/kg → airlock
at rt ventricle→ cardiovascular collapse.
-May occur as a result of gas entering
the systemic circulation via a patentpatent
cardiac foramencardiac foramen or through the
pulmonary capillary system.
-Can result in neurological dysfunctionneurological dysfunction
)delayed recovery, coma, fits,
1.Physiological effects depend on rate & volume of gasrate & volume of gas.
2.Effect tends to be less dramatic with COless dramatic with CO22.
3.May occur as a delayed phenomenonMay occur as a delayed phenomenon (late post-operative) if gas is
trapped in the portal circulation.
DIAGNOSIS of gas embolism during laparoscopy:
1.Suspect if hypotension develops during insufflation.
2.Oesophageal stethoscope= characteristic "Mill wheel" murmur.
3.Transoesophageal Echosonography: can detect even subclinical embol-i
G A S
1.Get rid of emboli:
_ place the patient in left lat. decubitus with the head down.
_ rapidly placed central venous catheter→ foamy blood.
_ external cardiac massage.
_ 100% O2
_ I.V. fluids
3. Stop gas:
_ turn-off gas flow.
_ desufflate the abdomen.
3. Cardiovascular effects: "more marked during the initial 30 min of insufflation"
a. ↓ cardiac ouput (COP):
due to ↓venous return secondary to:
•excessive pressure on IVCpressure on IVC.
•reverse Trendelenburg'sreverse Trendelenburg's (lap. upper
•loss of LL muscle toneLL muscle tone.
this decrease is not seen if:
• patient is normovolaemic.
• IAP is kept under 20 mmHg.
b. ↑ central venous pressure:
↑intra-abdominal pressure is
transmitted directly across the
paralyzed diaphragm to thoracic
c. ↑ mean arterial BP:
•due to ↑ systemic vascular
1.mechanical compression of aorta &
2.neurohumoral factors (e.g.
•Reverse Trendelenburg position canReverse Trendelenburg position can
compensatecompensate for ↑ ABP
d.↑ risk of thromboembolic events:
•venous engorgement & ↓ venous returnvenous engorgement & ↓ venous return.
•Many advanced lap. proceduresadvanced lap. procedures in which DVT prophylaxis was not given
demonstrate the frequency of pulmonary embolus. This usually is an
avoidable complication with the use of:
* sequential compression stockings.
* low molecular weight heparin (LMWH).
•In short-duration lap. proceduresshort-duration lap. procedures (e.g. appendectomy, hernial repair or
cholecystectomy), the risk of DVT may not be sufficient to warrant extensive
•Intraoperative oliguria is common with laparoscopyIntraoperative oliguria is common with laparoscopy due to:
•↑ intra-abd. P → direct pressure on kidney & its BVs → ↓renal blood flow
•↑ circulating ADH levels that also are found during pneumoperiton.
•↓ RBFRBF →↑ plasma reninplasma renin→↑ Na retention.Na retention.
•Effects of pneumoperitoneum on RBF are immediately reversible.
•Hormonal changes can ↓ urine output (UOP) for up to 1 hr after procedure
•During LAP, UOP is not a reflection of intravascular volume status.
SO…….. regarding IV fluid administration in uncomplicated procedures:
1. IV fluid administration should not be linked to UOP.
2. Compared to open surgery, more judicious I.V. fluid use is a
MUSTMUST because insensible fluid losses through the open
abdomen are eliminated.
Haemodynamic consequences of pneumoperitoneum are well
tolerated by healthy individuals for a prolonged period and by most
individuals for at least a short period.
Difficulties occur when a patient with compromised cardiovascular
function is subjected to a long lap. procedure (alternative approaches
should be considered).
Alternative gases suggested for laparoscopy include the inert gases
helium, neon and argon.
They cause no metabolic effects, but are poorly soluble in blood
(unlike CO2 & N2O)→ prone to create gas emboli if they have direct
access to the venous system.
PHYSIOLOGICAL CHANGES WITH PATIENTPHYSIOLOGICAL CHANGES WITH PATIENT
1. Cardiovascular changes:
•Head-up position: ↓VR, COP, mean ABP, ↑systemic and pulmonary
•Head-down position: vice versa
•Lateral decubitus position: direct pressure over the IVC may result in
2. Respiratory changes:
•Head down position:
* ↑ the risk of: * gas embolism
* hypoxia & atelectasis (by changes in intrathoracic blood
volume & small airway collapse)
* endobronchial intubation.
* :↓ * functional residual capacity (FRC)
* total lung volume
Gasless LaparoscopyGasless Laparoscopy
•An abdominal lifting deviceabdominal lifting device is placed through a 10-12 mm trocar at the
umbilicus to avoid the disadvantages of CO2 insufflation.
•Advantages of using abdominal lifting devices:
1* They create little physiologic derangement.
2* They significantly minimize the risk of gas embolization.
3* They may allow performing of MIS with standard nonlaparoscopic
4* They eliminate the need and maintenance of a gas-tight operating
Despite these inventions, technique of gasless LAP has not yet
achieved wide popularity may be due to:
1. The bulky naturebulky nature of most of these devices.
2.2. Greater postoperative painGreater postoperative pain than pneumoperitoneum.
3.3. ExposureExposure and working room are inferior.
• Because the physiological effects of pneumoperitoneum appear to
be most marked after initial abdominal insufflation and during high
pressure insufflation (> 14mmHg), the use of a hybrid system of low
pressure pneumoperitoneum (<5mmHg) combined with an
abdominal wall retracting technique may provide the best of both
1. From the surgical point of view, LAP is considered minimally invasive.
2. From the physiological point of view and body response, a number of
physiological changes occur as a result of:
* postural changes involved in patient positioning.
Physiologically, LAP is not considered minimally invasive, particularly
1. Patients with very old age.
2. Patients with very young.
3. Patients with significant pre-existing diseases.
(cardiovascular, pulmonary and neurological disorders).
3. The major problems during laparoscopic surgery are related to CO2-induced
pneumoperitoneum, these problems can be averted if certain precautions have
been kept in mind:
1.All cardiopulmonary-compromised patients should be assessed preoperatively
by a physician or a cardiologist.
2.Lower pressure pneumoperitoneum (10–12 mmHg) with proper patient
hydration can prevent cardiac problems.
3.Minimize operative time by the help of experienced person.
4.Use helium or nitrous oxide gas for pneumoperitoneum, if available in
1.A Guide to Laparoscopic Surgery book Wiley-Blackwell; 1st
(December 15, 1998) ISBN-10: 086542649X ISBN-13: 978-
2.A Guide to Laparoscopic Surgery. Ann R Coll Surg Engl. 2000
September; 82(5): 370.
3.Secrets of safe laparoscopic surgery: Anaesthetic and surgical
considerations. J Minim Access Surg. 2010 Oct-Dec; 6(4): 91–94.
4.Shakespeare's view of the laparoscopic pneumoperitoneum. JSLS.