surgery 4- principles of surgery (1)

8/14/2019 Surgery 4- Principles of Surgery (1)

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This is the 4thscript of surgery, for the lecture of Principles of surgery.The reference for this script was the record of the lecture and the book ,in

addition to some extra information and pictures to enhance your

understanding.

This lecture contains many points that may mislead you, by the end of thescript there are some flowcharts that summarize the most important points

without details, you can use them to arrange your information.

The reference from the book is chapter 3.

Principles Of Surgery

Human tissues have genetically determined properties that make their responses toinjury fairly predictable. Depending on this predictability, principles of surgerythat help to optimize the wound-healing environment have evolved through time

and through basic and clinical research.

DEVELOPING A SURGICAL DIAGNOSISMost of the important decisions concerning a maxillofacial surgical procedure

should be made long before the administration of anesthesia. The decision toperform surgery should be the culmination of several diagnostic steps. In the

analytic approach the surgeon first identifies

the various signs and symptoms and relevant historical information; then, using

available data and logical reasoning, the surgeon establishes the relationshipbetween the individual problems.

Lets say we have a patient that requires wisdom tooth extraction.

and lab tests.

differential diagnosis. In our minds we should always have a

set of diagnoses for the condition we have. For example the patient is

complaining of pain at the pre auricular area ; it might be due to wisdom, TMJ or

submandibular tumor etc ..

most probable to the least.

Each diagnosis is excluded one by one to reach the definitive diagnosis.

The initial step in the presurgical evaluation is:


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1-the collection of accurate and pertinent data: This is accomplished throughpatient interviews; physical, laboratory,and imaging examinations; and the use of

consultants when necessary. Patient interviews and physical examinations should

be performed in an unhurried, thoughtful fashion. The surgeon should not bewilling to accept incomplete data, such as a poor-quality radiograph, especially

when it is probable that additional data might change decisions concerning surgery.For a good analysis, data must be organized into a form that allows for hypothesis

testing; that is, the dentist should be able to consider a list of possible diseases andeliminate those unsupported by the data. By using this method, along with the

knowledge of which diseases have a probability of being present, the surgeon is

usually able to reach a decision about whether surgery is indicated.2- Clinicians also must be thoughtful observers. Whenever a procedure is

performed, they should note all aspects of its outcome to advance their surgical

knowledge and to improve future surgical results. This procedure should also befollowed whenever a clinician is learning about a new technique. In addition, aclinician should practice evidence-based dentistry by evaluating the purported

results of any new technique by weighing the scientific merit of studies used to

investigate the technique.Frequently, scientific methods are violated by theunrecognized introduction of a placebo effect, observer bias, patient variability, or

use of inadequate control

groups.

BASIC NECESSITIES FOR SURGERYLittle difference exists between the basic necessities required for oral surgery and

those required for the proper performance of other aspects of dentistry. The twoprincipal requirements are (1) adequate visibility and (2) assistance.

Although visibility may seem too obvious to mention as a requirement for

performing surgery, clinicians often overlook it. Adequate visibility depends upon

the followingthree factors: (1) adequate access, (2) adequate

light, and (3) a surgical field free of excess blood and other fluids.

-Adequate access requires: the patient's ability to open the mouth widely.Retraction of tissues( such as the lips , cheeks and tongue) away from the operative

field provides much of the necessary access. (Proper retraction also protects tissues

from being accidentally injured, for example, by cutting instruments.)Improved access also may require surgically created exposure the creation of

surgical flaps, which are discussed later in this script.


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-Adequate light is another obvious necessity for surgery. However, clinicians often

forget that many surgical procedures place the surgeon or assistant in positionsthat block chair-based light sources. To correct this problem, the light source must

continually be repositioned, or the surgeon or assistant must avoid obstructing the

light or use a headlight.

-A surgical field free of fluids is also necessary for adequate visibility. Highvolume suctioning with a relatively small tip can quickly removeblood and other

fluids from the field.

-As in other types of dentistry, aproperly trained assistant provides invaluable help

during oral surgery. The assistant should be sufficiently familiar with theprocedures being performed to anticipate the surgeon's needs. It is extremely

difficult toperform good surgery with no orpoor assistance.

-Aseptic technique includes minimizing wound and surgical field contaminationby pathogenic microbes and , this can be done by using antiseptic and disinfectant

solutions , wearing aprons and gloves, and placing the sterilized instruments on

the sterile sheet.

Operative techniques1) Each surgical procedure is started by: 1) doing an incision then2) retraction

of soft tissue flapto gain access and some surgeries require removal of bonethen 3) delivery of the tooth or rootthen4) debridement and irrigationisdone to smoothen sharp bony edges then 5) suturingand 6)post operative

care of the patient.

Incision

Few basic principles are important to remember when performing incisions. Which

are:

1- a sharp blade of the proper size should be used.

*The blade used is fixed on an instrument , this instrument is called the scalpel. In

oral surgery the scalpel used is number 3 scalpel.


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(number 3 scalpel) (scalpel with blade fixed on it)

*The rate at which a blade dulls ( becomes not sharp) depends on the resistance of

tissues through which the blade cuts.Bone and ligamental tissuesdull bladesmore rapidly than does buccal mucosa. Therefore the surgeon should change

blades whenever the knife does not seem to be incising easily.

*These are some types of blades used in oral surgery:

Blade number 11: used to do an incision in an abscess to drain it.

Blade number 15: most commonly used

Blade number 10: similar to number 15 blade but larger, usually

used by general surgeons to do excisions extraorally.

Blade number 12: used to do an incision in the posterior area of theoral cavity, especially in the maxillary tuberosity region ( curved)


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2-Use asingle firm continuous stroke when incising.

Repeated incisions are not allowed because they cause damage to blood vesselsand soft tissue which increases bleeding and may complicate our surgical

treatment.

*holding the scalpel is done using the pen grasp, for more control and tactile

sensitivity, and only the wrist should be moved not the whole forearm.

3-the surgeon should carefully avoid cutting vital structures when incising.

Thats why you should know anatomy of the head and neck specially the oralcavity. And the surgeon must incise only deeply enough to define the next layer .

In general we can say that: a- incisions in the buccal area of the lower premolar

should not be done to avoid injuring the mental nerve ( for example if I want to doan incision to remove an impacted lower second premolar , the vertical releasing

incision should be distal to the tooth away from the mental nerve area)

b-Incisions in the lower wisdom teeth area lingually should not be done to avoid

injuring the lingual nerve which is covered only by soft tissue in this area.

c-when using a scalpel the surgeon's focus must remain on the blade to avoid

accidentally cutting structures such as the lips or cheeks of the patient wheninserting and removing the blade to and from the mouth.

4- incisions through epithelial surfaces that the surgeon plans to

reapproximate should be made with the blade held perpendicular to the

epithelial surface ( 90 degrees).

This angle produces squared wound edges that areboth easier to reorient properlyduring suturing and less susceptible to necrosis of the wound edges as a result of

ischemia, any oblique incision will cause undermining of the edges which willcompromise the blood supply and subsequently interfere with wound healing.

5- incisions in the oral cavity should be properly placed.


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It is more desirable to incise through attached gingiva and over healthy bone. ( for

example: 1- in the upper maxilla area, in the first incision which is the verticalreleasing incision, we should not cross the canine eminence because this will cause

dehiscence and separation of the flap margin later on because its a prominent

area, 2- for a more esthetic outcome , the incision should not be done on the midportion of the dental papilla, it should be either including it or mesial or distal to it

but not in its middle )

Properly placed incisions allow the wound margins to be sutured over intact,healthy bone that is at least a few millimeters away from the damaged bone,

thereby providing support for the healing wound. Incisions placed near the teeth

for extractions should be made in the gingival sulcus, unless the clinician feels it isnecessary to excise the marginal gingiva or to leave the marginal gingiva

untouched..

Flap DesignSurgical flaps are made to:1- gain surgical access to the field, for example in

order to extract an impacted wisdom tooth I have to make a flap to gain access toit. 2- Or to move tissue from one place to another.

** Several basic principles of flap design such as : 1-making the flap with anadequate size and 2- a full thickness flap passing through mucosa, submucosa, and

periosteum must be followed to prevent the complications of flap surgery, whichare:1- flap necrosis, 2-dehiscence, and 3-tearing.

1- flap necrosisFlap necrosis can be prevented if the surgeon attends to four basic principles.

First, the apex (tip) of a flap should never be wider than the base, unless a majorartery is present in the base. Flaps should have sides that diverge () movingfrom the apex to the basein order not to compromise the blood supply of the flap.


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Because the source of blood supply to the flap is the periosteum which is found in

the area where the base of the flap is, so suppose that we do a flap that has a base

narrower than the apex, in this case all the parts of the flap contained within theborders of the base will have blood supply but the edges will not, and since the

base is the only blood supply source , these edges will not be supplied and havenecrosis , look at the figure below.

This is a wrong flap design, the red area will have This is the right Flap with the base wider than

blood supply while the edges in black will not the apex, and blood supply reaches the whole

which will lead to necrosis and delay wound healing. Flap.

Second, generally the flap base dimension (x) must not be less than heightdimension (y), and preferably flap should have x = 2y, the width is alwayslarger than the length.

For example if x=1cm , then y should be 0.5 cm

apex

base


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Third,

when possible, an axial blood supply should be included in the base of the flap, for

example a flap in the palate should be based toward the greater palatine artery .

An example on this is the cases of oroantral communication which is a common

complication, that may occur during an attempt to extract the upper back teeth or roots. ,

many techniques are used to close this communication like1) buccal advancement

flap and 2) palatal rotational flap.but we dont do a vertical releasing incision for

closure because we may hurt the greater palatine artery.

In the palatal rotational flap, We do two incisions that are long enough and rotate

the flap to close the fistula, by this the greater palatine artery will be included in

the flap, see the picture below.


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Fourth, the base of flaps should not be excessively twisted, stretched, or grasped

with anything that might damage vessels, because these maneuvers can

compromise the blood supply feeding and draining the flap.

The reason that may require the use of over retraction is: inadequate flap size, soyour flap should be big enough from the beginning .

2-Flap dehiscence

Flap margin dehiscence is the separation between flap margins after suturing

And it is prevented by: 1) approximating the edges of the flap over healthy bone,2)by gently handling the flap's edges,3) and by notplacing the flap under tensionwhich may lead to necrosis. Dehiscence exposes underlying bone, producing pain,

bone loss, and increased scarring.For example if I have a bony lesion and I want to do a flap to remove it, I go 5-8

mm away from the lesion and do the incision, so that later on suturing of the flap

happens on healthy bone and flap dehiscence is prevented.

Incisions should

be 5-8 mm away

from the area of

surgery

3-Flap Tearing

Tearing of a flap is a common complication of the inexperienced surgeon who

attempts to perform a procedure


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using a flap that provides insufficient access. Because a properly repaired long

incision heals just as quickly as a short one, it is preferable to create a flap at theonset of surgery that is large enough for the surgeon to avoid either tearing it or

interrupting surgery to enlarge it.

TISSUE HANDLINGThe differencebetween an acceptable and an excellent surgical outcome often restson how the surgeon handles the tissues. The use of proper incision and flap design

techniques plays a role; however, tissue also must be handled carefully. Excessive

pulling or crushing, extremes of temperature ( like drilling in the bone withoutusing copious amounts of irrigation), desiccation, or the use of unphysiologic

chemicals ( like using hydrogen peroxide instead of normal saline for irrigation by

mistake) easily damage tissue .In addition, tissue should not be over aggressivelyretracted to gain greater surgical access, Therefore the surgeon should use carewhenever touching tissue.

HEMOSTASISPrevention of excessive blood loss during surgery is important for preserving a

patient's oxygen-carrying capacity. However, maintaining meticulous hemostasis

during surgery is necessary for other important reasons. One is the decreasedvisibility that uncontrolled bleeding creates. Even high volume suctioning cannotkeep a surgical field completely dry, particularly in the well-vascularized oral and

maxillofacial regions. Another problem bleeding causes is the formation of

hematomas ( collection of blood inside tissues). Hematomas place pressure onwounds, decreasing vascularity; they increase tension on the wound edges; and

they act as culture media, potentiating the development of a wound infection.

Techniques for Promoting Wound Hemostasis (the process that stops bleeding):

1) by assisting natural hemostatic mechanisms. This is usually accomplished byplacing pressure on bleeding vessels which causes stasis of blood in vessels, and

promotes coagulation. A few small vessels generally require pressure for only 10to 30 seconds, whereas larger vessels require 10 to 20 minutes of continuous

pressure.


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2) the use of heat to cause the ends of cut vessels to fuse closed (thermal

coagulation). this is done by using a device called Microcautery ,Heat is usuallyapplied through an electrical current that the surgeon concentrates on the bleeding

vessel by holding the vessel with a metal instrument, such as a hemostat, or by

touching the vessel directly with an electrocautery tip.

3)by suture ligation.

4)placement of a pressure dressing over the wound. This creates pressure on the

small vessels that were cut, promoting coagulation.

5)Placing vasoconstrictive substances, such as epinephrine, in the wound or byapplying procoagulants, such as commercial thrombin or collagen, on the wound.

Dead Space Management

Dead space in a wound is any area that remains devoid of tissue after closure

of the wound. Dead space is created by either removing tissue in the depths of a

wound or by not reapproximating all tissue planes during closure. Dead space in awound usually fills with blood, which creates a hematoma with a high potential for

infection.

Principles

during Thermal

Coagulation

the patient must be grounded, to allow the current to enter the

body.

the cautery tip and any metal instrument the cautery tip contacts

cannot touch the patient at any point other than the site of the

bleeding vessel. Otherwise the current may follow an undesirablepath and create a burn.

the removal of any blood or fluid that has accumulated around th

vessel to be cauterized because Fluid acts as an energysumpandthus prevents a sufficient amount of heat from reaching the vesse

to cause closure.


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.

DECONTAMINATION AND DEBRIDEMENT

Decontaminationis easily accomplished by repeatedly irrigating the wound

during surgery and closure. Irrigation dislodges bacteria and other foreignmaterials and rinses them out of the wound. Irrigation can be achieved by forcing

large volumes of fluid under pressure on the wound using a syringe. Althoughsolutions containing antibiotics can be used, most surgeons simply use sterile

saline or sterile water.

Wound debridementis the careful removal from injured tissue of necrotic,foreign, and severely ischemic material that would impede wound healing.

EDEMA CONTROL

Edema is an accumulation of fluid in the interstitial space because of transudationfrom damaged vessels, and lymphatic obstruction by fibrin .

Dead space can

be eliminated

in four wa s

1) suturing tissue planes together to minimize the postoperative

void

2) place a pressure dressing over the repaired wound. The dressingcompresses tissue planes together until they are either bound by fibrin or

pressed together by surgical edema (or both).

3) place packing into the void until bleeding has stopped and then remove the

packing.( packing means the filling of a wound or cavity with gauze, sponges,

pads, or other material;) The packing material is usually impregnated with anantibacterial medication to lessen the chance of infection

4)the use of surgical drain, which is a device, such as a tube, sutured into the opening oa wound or dental cavity to facilitate discharge of fluid or purulent material, as It makes apath for blood to run through, so instead of accumulating inside blood goes outsidethrough this channel.


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the greater the amount of tissue injury, the more loose connective tissue that isthe greater the amount of edema contained in the injured region, the more

edema is present.

**For example attached gingiva has little loose

CT, so it exhibits little tendency toward edema.

While the lips , cheeks,and FOM contain large

amounts of loose CT and can swell significantly

**Edema is a common complication after surgical extractions, but sometimes it

may also happen after simple extractions if the extraction was traumative.

** The dentist can control the amount of postsurgical edema by performing

surgery in a manner that minimizes tissue damage.

**also ice packs can be used, we ask the patient in the first day of surgery to putice from 5-10 minutes every 3-4 hours, which can decrease the vascularity in that

area and decrease edema.

**We can use medications, mainly high dose short termcorticosteroids.In

general we use Dexamethasone which is an anti inflammatory drug which has the

ability to decrease edema.

Variables that help determine

the degree of postsurgical

edema

Amount of tissue injury Amount of CT in the injured

region


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PATIENT GENERAL HEALTH AND NUTRITIONProper wound healing depends on: a patient's ability to resist infection, toprovide essential nutrients for use as building materials, and to carry outreparative cellular processes. Numerous medical conditions impair a patient's

ability to resist infection and heal wounds. These include conditions that 1-establish a catabolic state of metabolism, 2-that impede oxygen or nutrient delivery

to tissues,3- and that require administration of drugs or physical agents thatinterfere with immunologic or wound-healing cells.

** Examples of diseases that induce a catabolic metabolic state include:

1) poorly controlled insulin-dependent diabetes mellitus,

2) end-stage renal or hepatic disease,3) and malignant diseases.

**Conditions that interfere with the delivery of oxygen or nutrients to woundedtissues include:

1) severe chronic obstructive pulmonary disease (COPD),2)poorly compensated congestive heart failure (hypertrophic cardiomyopathy),3) drug addictions, such as ethanolism.

** Diseases requiring the administration of drugs that interfere with host defenses

or wound-healing capabilities include:1) autoimmune diseases for which long-term corticosteroid therapy is given2)malignancies for which cytotoxic agents and irradiation are used.

The surgeon can help improve the patient's chances of having normal healing of anelective surgical wound by evaluating and optimizing the patient's general health

status before surgery. For malnourished patients, this includes improving thenutritional status so that the patient is in a positive nitrogen balance and an

anabolic metabolic state.

This is the end of the lecture, the following charts include the main points of some

topics.


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Operative

Techniques

incision Flaptooth or

root

delivery

debridement

and

irrigation

suturing

patient

post

operative

care

Incision

principles

sharp blade

of propersize used

single firm

continuousstroke

avoid

cutting vitalstructures

blade held

perpendicular to

epithelium

incision

properlyplaced


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Best Of Luck Dear Colleagues

Nagham Ayman Rabi

flap necrosis preventionprinciples

the base

wider thanthe apex

width of the

flap baselarger thanthe length

axial blood

supplyincluded in

the base

avoid overretractionof the flap

Promoting wound

hemostasis techniques

placing

pressure

thermalcoagulation

sutureligation

pressuredressing

vasoconstrictivsubstances

surgery 4- principles of surgery (1)

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