Dr.Mohammad Zarin
MBBS, FCPS, MRCS, FMAS
Associate Professor, SEW
Khyber Teaching Hospital

Outline of Presentation
• Ergonomics
• Physiology
• Instruments

ERGONOMICS

2 D Image
No depth Perception
No tactile feedback
Counter-intuitive
Limited movements
Magnification

Open Surgeon Vs Lap Surgeon
How do they differ?!
Open Surgeon
• Fast
• Hand is as good as eyes
• Dissection precedes
• Ergonomics: Optional
Laparoscopic Surgeon
• Slow and steady
• Stop when you don’t see
• Haemostasis precedes
• Ergonomics: Vital

To be an efficient Surgeon…
• Equipments
• Environment
Concentrate on

PATIENT POSITION
Produce gravitational displacement of viscera away
from surgical site.
Trendelenberg Rev Trendelenberg
15-20˚ head down 20-30˚ head up
Endobronchial
intubation
Predisposition to DVT

Patient positioning

Ergonomics
• Straight Line principle
• Triangulation
• Manipulation angle
• Elevation angle
• Low lying table
• Gaze down view

Straight Line Principle
Surgeon
Pathology
Monitor

Visual Axis and Motor Axis

Co Axial alignment

Base Ball Diamond Concept
& Triangulation
Monitor
S
C
R
L
P

Manipulation angle
Azimuth Angle
Manipulation Angle
30-45 degree
60-90 degree

Elevation angle

Ideal angles!
1. Manipulatation angle: 60 degree
2. Azimuth angle: Equal/30 degree each
3. Elevation angle: 60 degree

Ergonomics of Hand Instruments
• Tip
– Range of movements
• Conventional Vs Robotic instrument: 4: 7

Ergonomics of Hand Instruments
• Tip
– Range of movements
• Conventional Vs Robotic instrument
• Length of the shaft

Fulcrum Effect of Hand Instruments
1: 1

Ergonomics of Port Placement

Ergonomics of Hand Instruments
• Tip
– Range of movements
• Conventional Vs Robotic instrument
– Force transmission
• Length of the shaft
• Handle design

Ergonomic handles…

Surgeon’s Stance
Ideal relaxed stature Tiring

Ideal Relaxed Position
-straight head, in the axis of the trunk,
without rotation or extension of the cervical spine;
- shoulders in a relaxed and neutral position;
- arms alongside the body
- elbows bent to 70 to 90 degrees
- forearms in an horizontal or slightly descending axis-
-hands pronated (physiological resting position);
- hands and fingers lightly grip the handles/handpiece
•Waist line table
•Gaze down view of monitor
•Straight line principle
•Triangulation

PHYSIOLOGICAL EFFECTS OF
LAPAROSCOPY
Can be:
 Mechanical
 Metabolic
On
• Cardiovascular
• Pulmonary
• Gastrointestinal
• Renal
• Peripheral vascular

Cardiovascular Effects:
↑ IAP
↓ CO
↓ VR
↓ SV
↑ Afterload
↑ MAP
HR
x =
↑ Vasopressin &
Catecholamines
↑ CO2
↑ CVP ↑ PCWP ↑ SVR
↓ VR ↓ LVEDV

Cardiovascular Effects:
• Cardiac Output
– Variation between studies
– < 30% decrease when observed
– On insufflation; ∞ ↑ in I.A.P; transient
• generally noted in:
– ASA Class III/IV
– hypovolemic patients
– PP > 15 mm Hg
– reverse Trendellenberg position

Respiratory Effects:
↑ IAP
↑ cephalad shift
diaphragm
paradoxic
diaphragm motion
↑ ITP
↓ FRC
↑ RR
↑ CO2
↑ Ve & work of breathing
↓chest wall
compliance
Hypercapnia
↑ PAWP +
Alveolar
Collapse
↓ TV

Respiratory Complications:
• Pneumothorax / Pneumomediastinum /
Pneumopericardium
– 2° to diffusion of gas from pneumoperitoneum
• Accidental diaphragm injury / pre-existing diaphragmatic
defect
– 2° to rupture of blebs with ↑ PAWP
• Gas Embolism
– 2° to vascular injury
• trocar / needle insertion on insufflation / intra-op vessel injury

Gastrointestinal effects:
↑ I.A.P.
↓ Mesenteric & celiac flow
↓ hepatic
artery flow
↓ hepatic
perfusion
↓ perfusion
intestines &
stomach
↓ Portal
flow
↑ LFTs
↓ intestinal &
gastric pH

Renal Effects:
↑ I.A.P.
↓ GFR
↓ERPF
↓ U/O
RAAS
↑ CO2

Renal Effects:
• U/O return to baseline within hours
• No long-term change in GFR
• No change in Cr, BUN

Peripheral Vascular Effects:
↑ I.A.P.
Reverse
Trendellenberg
Venous stasis
↓ VR
↑ Risk DVT?

Peripheral Vascular Effects:
• Incidence of DVT, PE generally lower post
laparoscopic procedures
– Secondary to improved prophylaxis?
– Risk increased with longer procedures and
reverse Trendellenberg

Laparoscopic Instruments
• Hand instruments