POWERED INSTRUMENTS

Electric Instruments

Mono-polar diathermy(cont)


The purpose of the indifferent large surface electrode in mono-polar diathermy, is to provide a surface of sufficient area to avoid any heat effects at this site.

- This is because the indifferent electrode is in contact with hundreds and thousands of more cells than the live electrode which results in a lower density of current in each of these cells.
- If the electrode is applied correctly as described below; little heat is generated in this area.
- The commonest type of indifferent electrode is a flexible metal plate. The thin flexible metal plate electrode can either be placed under the patient’s body (sacrum) or carefully bandaged round the thigh to ensure even contact with the skin.
- It is necessary to use electrode jelly, if the patient is hairy, shaving beforehand is advisable as hair acts as an electrical resistance.
- If the patient’s skin is dry as in our dry climate, moistening with water or saline can be used with advantage before applying the plate. The plate can be wrapped in a moist sheet.
- Replace a plate electrode which becomes uneven, otherwise areas of irregular contact with the skin result, which could allow points of high current density and risk of burns.
- The electrode is connected to the high frequency electrosurgical unit indifferent or earth terminal by a heavy insulated wire.
- Risk of accidents is possible.
Bipolar diathermy is a safer alternative.


With a bipolar system the surgeon’s instrument, usually in the form of a forceps, Combines both electrodes so that current flows down both limbs of the forceps
Only the tissue gripped between the tips of the forceps receives the current.
Eliminating the need for an indifferent electrode.
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POWER INSTRUMENTS IN SURGERY

ELECTRIC INSTRUMENTS


Diathermy
Diathermy machines generate high frequency electric current.
This energy can be used by the surgeon to cut skin and deeper tissues.
It can also be used to coagulate tissue to limit bleeding.
These effects are the result of heat generated in the tissues



Surgical diathermy is frequently used in surgery to limit bleeding..
- When this current is passed through the patient’s body between two electrodes, the effect is to produce a concentration of current at the smaller electrode in the hand of the surgeon.
- As the surgeon applies his live (small) electrode to the tissues, the current passes through the touched tissue cells and owing to the tissue’s electrical resistance, heat is generated at this contact point.
- The effect is localized because with mono-polar system the current from the live (small) electrode spreads out in the patient’s body and travels to the indifferent electrode which is a large electrode placed in contact with the patient’s body (thigh or sacrum).
- A high density of current occurs only immediately beneath the live electrode because further away (except under fault conditions) the current density is too small to have any heating effect.
- Fault conditions are produced by the contact of patients body with the metallic table
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THE FINAL SCENE

We show here some views thru the endoscopes
The upper GI endoscopy shows views of stomach mucosa
The lower GI shows colon and removal of polyps






WHAT ARE THE DIFFERENT GASTROINTESTINAL FIBRESCOPES (INCLUDING GASTRSCOPES, DUODENOSCOPES AND CLONOSCOPES)?

Based on the angle of view are three types of instruments:-

1. Forward or oblique (for oblique) viewing for examination and
biopsy(a)
This is suitable for examining the oesophagus, most of the
stomach and the upper part of the duodenum
2. Side or lateral viewing for examination, biopsy and operative
procedures in the duodenum(b)
This is needed when full examination of oesphagus, stomach,
duodenum and biliary system is required. This includes the
fundus of the stomach and the duodenal bulb
3. Forward viewing with two channels for complex operative
procedures.
This is generally larger in diameter than the previous two and
has suitable dimension channels incorporated for operating
instruments. A wide range of procedures can be undertaken(c)

All three types of instruments can be obtained from several
manufacturers
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KEY HOLE SURGERY

CARE OF FIBER OPTIC INSTRUMENT
As mentioned earlier post it is possible to undertake surgery
Through the fiber optic endoscope
The working end of the endoscope has outlets for instruments
The instruments are also adapted to reach and function at the operating site




WHAT ARE THE RULES OF SPECIAL CARE OF FIBRE-OPTIC ENDOSCOPES?

The special care required for fiber-optic instruments after
use:
The first principle is that `the useful life of endoscope
instruments is at risk if too many users with different use, and
Maintenance protocols, are using the same instrument.

- Debris and mucus must be removed from the instrument, and the
Channels immediately after use, with a mild detergent such as
Savlon 1 per cent
- Followed by rinsing in warm water
- After thorough cleaning, the insertion tube only of the
endoscope, can be disinfected by immersion in a chemical
fluid such as glutaraldehyde (Cidex)
- Endoscopes used for intra cavity operative procedures on
penetrating tissues, i.e., laparoscopes, arthroscopes,
thorascopes, choledocoscopes etc., must be used in a sterile
condition
- The length of fibroptic light cable, which connects the light
source to the endoscope, must be cleaned at end of each
procedure and handled with great care to prevent damage to
the light conducting glass fibres.
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ENDOSCOPE THE PEEP TOOL

Endoscopes brought about a significant advance to surgery.
You can now see lesions that previously you could not.
You can now take a biopsy under vision and get tissue diagnosis
You can now see the effect of treatment on a lesion.
You can now keep along term record of the lesion for followup.
You can now use endoscopes to execute surgical procedures.



What is the light source



The fiber light bundle is connected at one end to the light
source and at the other to the endoscope.
- It contains a bundle of up to 20,000 flexible optical fibers
which can conduct light but not capable of carrying an
Image (E as shown in Fig 7.1)
- The bundles transmit a pre-focused light of high intensity
and uniform density to the endoscope
- The bundle’s outer covering is metal and PVC, and is flexible
- This light is called cold light since it carries no heat with it


- In addition, a separate set of up to 36,000 optical fibers
capable of carrying an image terminating proximally at an
Eyepiece, and distally at a lens at the end of the endoscope
(F as shown in Fig 7.1)
- Both these sets of optical fibers are contained in a
protective sheath of endoscope, generally this sheath
Incorporates additional channels for:
. Suction (G as shown in Fig 7.1)
. Gas inflation/irrigation (H as shown in Fig 7.1)
. A passage for flexible biopsy or operative forceps and
Electrodes Fig 5.3
. Some special instruments used thriugh this port are shown
in Fig 5.4
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ENDOSCOPY THE PEEP INSIDE

ENDOSCOPY
WHAT ARE RIGID ENDOSCOPES where are the used?

These viewing instruments are metallic telescopes, with light for Diagnosis, and biopsy.

They are introduced through natural body orifices eg. Bronchoscopy, esophascopy, colonoscopy etc.
-Today rigid endoscopes are also being used to view the interior of *joints (arthroscopies) and
*the kidney (nephroscope) and
*abdomen (laparoscope).

They are introduced through incised openings. They have four
Basic components:

* Eye piece (Viewing lens)
* Body tube contains light guide connector, valves to channels
* Shaft (lens channels)
* Distal end Objective lens

WHAT ARE FIBREOPTIC ENDOSCOPES?

These sophisticated instruments have made the diagnosis of
Lesions in the accessible segments of the GI tract possible,earlier, and accurate, since visual imaging, and biopsy of the lesions is possible.
High resolution images can be recorded on:
* Color films for case of record for follow up
* Cine film for arranging learning film material
* Television monitor for ease of viewing of procedure and learning
For realtime assistants

Fibre-optics lighting and imaging systems have replaced the
Conventional rigid optic and light systems in endoscopes.
- Fibre-optics is a term applied to a system for transmitting
light and images through thin optical fibers by total
Internal reflection Fig 5.1
- The fibre-optic endoscope system consists of three parts:
. The light source or generator unit (A as shown in Fig 7.1)
. The insertion tube with the optical image bundle (B as
shown in Fig 7.1)
. The instrument or endoscope control section near the eye
Piece(C as shown in Fig 7.1)
. The light source is a high-intensity lamp in a box with an
In-built curved reflector (D as shown in Fig 7.1)
- This ensures that cold light is passed to the instrument or
Endoscope since the heat is left in the light source box
- Special lamps such as quartz iodine, metal halide and xenon
have been developed to give a higher intensity of light of
up to 500 Watts.
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SET UP THE MICROSCOPE

STEPS OF PREPARATION OF THE MICROSCOPE FOR THE OPERATION

- Position the microscope over the table for the operation, and
as required by the surgeon, be sure to leave space required
by the assistant, scrub nurse, anesthesia team, equipment
and sterile trolleys
- Arrange the path of the mains lead from the wall socket to
Ensure that it is not in the path of flow of the OT staff

- check and tighten, if necessary, the safety locks between
Microscope and stand

- Ensure that correct objectives and binocular tubes are
Inserted for the particular operation
- Clean the objectives and eyepieces of main, and assistants’
Microscope
- Switch on the microscope
First at the wall socket
Second at the stand
Switch on the lights
- After the operation this procedure of switch off must be reversed
- First switch off lights, next stand, lastly wall switch
- Ensure all sterilzable caps or drapes are available

WHEN NOT IN USE CARE

Dust is very harmful for microscopes thus they should be kept
Covered with a dust cover when not in use and never left without
Objective, binocular tube or eyepieces fitted.
* Cameras are kept locked up for security; the dust cap should be put on the outlet
* All accessories, spare objectives, and eyepieces, should be
kept in dust proof containers
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