Ergonomics & Physiology In Laparoscopic Surgery

Dr.Mohammad ZarinMBBS, FCPS, MRCS, FMASAssociate Professor, SEWKhyber Teaching Hospital

Outline of Presentation

• Ergonomics• Physiology• Instruments

RAAS

ERGONOMICS

2 D ImageNo depth PerceptionNo tactile feedback

Counter-intuitiveLimited movements

Magnification

Open Surgeon Vs Lap SurgeonHow 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

PathologyMonitor

Visual Axis and Motor Axis

Co Axial alignment

Base Ball Diamond Concept& TriangulationMonitor

S

C

R

L

P

Manipulation angle

Azimuth Angle Manipulation Angle

30-45 degree60-90 degree

Elevation angle

Ideal angles!

1. Manipulatation angle: 60 degree2. Azimuth angle: Equal/30 degree each3. 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

HRx =

↑ 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