ophta micro surg

1. Basics of Ophthalmic
Microsurgery
By Sagni Jelkeba (MD)
Ophthalmologist
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2.  Objectives
– At the end of this course, you will be able to:
– Describe peculiarity of ophthalmic microsurgery
– Describe different types of ophthalmic incisions
– Describe and classify sutures used in ophthalmology
– Describe and classify common ophthalmic instruments --- surgical blades,
forceps, needles and needle holders
– Describe wound construction and closure
– Demonstrate different type of suture materials, suturing and knotting
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3.  Outlines
– Introduction
– Peculiarities of Microsurgery
– Ophthalmic Incisions --- definition, dynamics of incision, cutting instruments
– Blades used in Ophthalmic Surgery
– Techniques to open Anterior Chamber
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4. – Principles of Wound Closure
– Suture materials and Needles
– Needle holders
– Ophthalmic forceps
– Common knotting techniques
– Basic instrument handling
– Pearls of Eye surgery
– Summary
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5.  Introduction
– In any surgical field, the importance of suturing is self evident
– In eye surgery, proper suturing technique is paramount
– Lack of elasticity of the tissues
– The influence of sutures on the visual outcome
• Inappropriate suture placement and tying can impact visual function
– If wound construction and closure are not astigmatically neutral:
– Altered visual outcome
– Need of further surgical intervention
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6. – Similarly, poor wound repair on lid margins can have a long-term effect on the
eye --- affects lid closure and tear flow
– The closure of surgical wound relies on apposing the surfaces and planes of
tissues --- appropriate healing
– Knowledge of the biology of wound healing is important
– Key to modify the processes involved to achieve the desired wound
architecture
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7. – One thing to notice every time is that, wound related complications are more
severe in the eye
– The close proximity of tissues allows for rapid spread of infection
– The limited blood supply inhibits treatment
– The same limited blood supply alters wound healing
– Any surgical wound need to be managed well
– Sequence of good wound management:
– Preparation --- adequate cleaning of surgical surfaces
– Excellent aseptic technique
– Thorough postoperative care
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8.  Peculiarities of Microsurgery
– Microsurgery is distinct from general surgery, in that:
1. The visual field is restricted --- as is the space for manipulation between
the microscope and the operative field
2. The operating microscope forces the surgeon to assume a particular
posture --- often maintained for several hours
3. The surgeon should sit in a Natural Position
» Leaning slightly forward --- with a straight back and relaxed shoulders
» The surgeon’s body must be sufficiently under the head of the patient
» Both feet should be flat on the floor
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9. – The operating microscope consists of the following elements:
– Objective
– Magnification system
– Beam splitter
– Oculars
– Focus and magnification are adjustable with a remote foot control --- esp. for
retinal surgery
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10.  Ophthalmic Incisions
– Incision is a clean cut performed on a surface
– Instruments required to carry out incisions are called cutting instruments
– Characteristics of cutting instrument are designed to overcome the Cohesive
Resistance of tissues
– Note!
– Avoid using blunt instruments for incision --- may create undesired wound
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11. – Section:
– The result of direct application of blade of the cutting instrument
– Severs the fibers at the point it comes into contact
– Blunt dissection (cleavage):
– A technique of splitting various layers without direct severing of the fibers
– Possible in preformed tissue spaces
– Tissue fibers offer little resistance to stretching
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12. • Dynamics of Incision
– Incision is performed by exerting pressure with a blade on a tissue
– Incision is of differing shape and depth depending on:
– The force applied
– Path in which the cutting instrument is guided
– The speed of execution
– The instrument’s shape, size and the material it is made of
– Compactness and tightness of the tissue
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13. – Thus, parameters of incision depends on 3 main variables
– Characteristics of the cutting instrument
– Characteristics of the tissue
– Surgeon’s guidance of the instrument
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14.  Characteristics of cutting instrument
– Has 3 main parts --- handle, blade and carrier
– The handle transmits:
– The force of the surgeon’s hand to the tissue
– The tactile feedback to the surgeon
– Cutting edge --- a surface which comes into contact with the tissue
– Carrier --- supports the blade and connects to the handle
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15. – Shape of the blade and the carrier affect the dynamics of the instrument
– Cutting Instrument
– Principal materials used --- stainless steel and diamond
– Shape --- pointed, linear, curvilinear
– Includes --- blades, knives, scissors
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16.  Characteristics of the tissue
– The sectility of tissues is determined by:
– The compactness and strength of its fibers
– Their tension --- a taut tissue is more sectile
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17.  The Surgeon’s Intervention
– The surgeon can influence the cutting ability of the blade by adjusting his force
on the instrument --- thereby, on the tissue
– The pressure necessary is proportional to the resistance met by the instrument
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18.  Blades Used in Ophthalmic Surgery
– There are different types of blades used in surgery
– However, the three commonly used in ophthalmic surgery --- No.11, No.12 and
No.15
– Each blade is designed for a specific purpose
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19. – No.11 Blade
– Character --- sharp tip
– For stabbing incisions in the mucosa or skin --- making deep wound
– Used for:
• Chalazion incision and curettage
• Opening of lacrimal sac during DCR
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20. – No.12 Blade
– Character --- sickle shape with the sharp tip and cutting edge on the inside of
the curve
– Indications:
• Operating at the base of a small incision --- the cutting edge is guarded
to avoid injury to surrounding tissues
– Used for:
• Suture removal
• Cutting of nasal or lacrimal mucosa during DCR
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21. – No.15 Blade
– Character --- rounded contour
– Used for cutting skin, mucosa, sclera
• As in blepharoplasty, skin excision, scleral incision, . . .
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22.  Techniques for Opening AC --- Example
– Incisions to open the AC --- corneal, limbal, scleral
– The knowledge of surgical anatomy and structural importance of the limbus is
mandatory
– Involves incision of different tissues:
– Incisions of conjunctiva
– Incision of lamellar tissues --- the cornea and sclera
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23.  Principles of Wound Closure
– The principles of wound closure vary
– Based on whether the wound is extraocular, or it involves opening the
pressurized globe and subsequent closure
– Ways of closure:
– Extraocular --- placing suture, cauterization
– Globe opened --- creating water tight wound, suturing
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24.  Sutures Materials
– Sutures are used to hold wound margins together so that scar tissue can rapidly
and easily repair discontinuity
– The sutures must:
1. Align anatomic surfaces and appose the incised tissue edges in their normal
anatomic position
2. Provide adequate compression and minimal space for the scar tissue to
bridge
3. Counteract the forces which tend to divide the surfaces, for long enough to
allow the scar to strengthen
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25. – The length of time for sutures to be there varies according to the tissue
– For conjunctiva --- about 7 days
– For cornea --- 3-6 months (till 12 months for PKP)
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26. – Criteria for ideal suture:
– Easy to handle
– Minimal tissue reaction
– Does not support bacterial growth
– High breaking strength
– Easy sterilization
– No allergic reaction
– No carcinogenic action
– Absorbed after serving its function
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27. – Sutures are classified based on:
– Material it is made of --- natural, synthetic, metallic
– Its structure --- monofilament or multifilament (braided)
– Absorbability:
• Non-absorbable
• Absorbable --- suture that loses most of its tensile strength within 2
months
– Size (diameter) --- 2/0 to 11/0
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28. – Non-absorbable Sutures:
– Nylon --- polyamide
– Silk
– Prolypropylene --- e.g. Prolene
– Polyester --- e.g. Mersilene
– Absorbable Sutures:
– Polyglactin 910 --- e.g. Vicryl
– Polyglycolic acid --- e.g. Dexon
– Polydioxanone (PDS)
– Plain gut
– Chromic gut
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29. 29
Absorbable Sutures
Materials Polyglactin 910
(e.g. Vicryl, Ethicon)
Polyglycolic acid (e.g.
Dexon)
Plain gut Chromic gut
Tissue reaction Mild Mild Marked Moderate
Tensile strength 2- 3 weeks 2-3 weeks week 2-3 weeks
Other characteristics Hydrolytic degradation Hydrolytic degradation Enzymatic degradation Ezymatic degradation
Indications
Commonly used in strabismus
surgery
Seldom used in anterior
segment surgery
Seldom used in
anterior segment surgery
Used in lid surgery such as
Weiss’s procedure
to encourage fibrosis
Seldom used in anterior
segment surgery
Used in lid surgery such as
Weiss's procedure
to encourage fibrosis

30. Non-absorbable Sutures
Materials Polyamide (Nylon) Silk Polypropylene (e.g. prolene)
Polyester (e.g. Mersilene)
Types Monofilaments
2 types --- virgin silk, and braided silk
Both are multifilament
Monofilaments
Multifilament
Monofilaments
Tissue reaction Minimal Moderate Minimal Minimal
Tensile strength
High, losing 10 to 15% of
strength per year
Moderate, lasting 3-6 months
High, maintain strength for over 2
years
High, permanent
Other characteristics
Mild elasticity
Stiff suture ends --- must
be buried to
avoid irritation
Inelastic suture ends soft
and therefore well-tolerated
Most elastic suture materials
Stiff suture ends and irritate if not
buried
Strongest monofilament and
less elasticity than other
monofilaments
Indications
Most widely suture for
corneal wound sutures
Rarely used to close corneal wound
sutures but often used as stay sutures.
Used mainly in iris repair and
intraocular lens fixation
Prefer by some surgeons for its
low elasticity & high tensile
strength
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31. – Advantages of monofilament over multifilament:
– Provides easy passage through the tissue --- whereas multifilament tends to
provide tissue drag
– Does not support bacterial growth --- whereas multifilament provide a nidus for
infection
– Causes less scaring and tissue reaction --- smooth surface and less surface area
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32. – Advantages of multifilament over monofilament:
– Easier to manipulate --- easy knotting
– Higher tensile strength
– Maintains tensions on a wound after the 1st throw
– Use of 2-1-1 or 1-1-1 tying sequence --- versus 3-1-1 or 3-1-1-1 for
monofilament
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33. • Commonly Used Suture Materials
– Absorbable Sutures
1. Polyglactin (Vicryl):
• has a duration of about 2 to 3 weeks
• Although it has a high tensile strength, this tensile strength decreases
as the suture mass is absorbed
• Available in braided or monofilament varieties
2. Collagen suture:
• Has a shorter duration and a lower tensile strength than does
polyglactin
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34. 3. Gut suture:
• has duration of approximately 1 week, with an increased amount of
tissue reactivity
• Because gut is composed of sheep or beef intestines, an allergic
reaction is possible
4. Chromic gut suture:
• differs from plain gut in that it has a longer duration of action, typically
2 to 3 weeks
• It has less tissue reactivity than plain gut
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35. – Non-absorbable Sutures
– A material such as nylon is much more slowly broken down over many months,
and polypropylene, and other modern synthetics are much more inert
– Nylon:
• High tensile strength --- but, loses 10-15% of its strength every year
• Is a relatively elastic material
• Causes minimal tissue inflammation
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36. – Polyester and Polypropylene:
• Are thought to be permanent --- used for iris repair
• Have high tensile strength
• Similarly, do not cause much tissue reaction
– Silk:
• Less permanent --- has a duration of 3-6 months
• Often associated with a greater amount of tissue inflammation
• Very easy to tie and handle
• Well tolerated by patients in terms of comfort
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37.  Suture Needles
– Suture needle has 3 parts:
– Swage (connection point for the suture)
– The body
– Point
– All needles are made of stainless steel
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38. – The 5 geometries of a needle:
– Length
– Chord length --- determines the width of bite
– Radius
– Needle diameter
• Measured in mils (1/1000 of an inch) --- 1 mil is about 25 µm
• Smaller diameter needle requires less force and cause less trauma
during passage
– Bicurve --- two radii
• The radius near the point is usually shorter than the radius of the body
near the swage
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39. – Shapes of curvatures of the needles
– ⅛ circle, ¼ circle, ⅜ circle, ½ circle, ⅝ circle
– Bi-curve, compound curve, straight
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40. – Ideal suture needles should have:
– Enough rigidity to prevent easy bending
– Sufficient length --- can be grasped by needle holder during passage and
retrieval without causing tissue damage
– Sufficient diameter to create a tract for the suture knot to be buried
– As atraumatic as possible
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41. • Common Suture Needles in Ophthalmology
– Different types of suture needles available in ophthalmic surgery
– Grouped into 4 types --- based on their point configuration
– Cutting
– Reverse cutting
– Taper point
– Spatula
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42. Point Cutting Reverse cutting Taper point Spatula
Diagrams
Configurations
Triangular with cutting edge
at the top
Cuts at tips and edges of the
needle
Triangular with cutting edge at the
bottom
Cuts at tips and edges of needle
Round and taper to a point
Cuts at the tip only
4 or 6 sided with cutting edges on
the side
Cuts at tip and sides parallel to the
tissue plane
Properties
Suture canal extends
superficial to the path
of needle tip
May pull out tissue during
needle passage
Suture canal extends deep to the path of
needle tip
Used for resistant tissue
Ideal for oculoplastic Surgery as the
needle allows easy passage through
epidermis
Accidental perforation may occur with
partial thickness suture such as rectus
scleral fixation
Atraumatic
Produces the smallest hole of
all needles
Useful in iris repair
Allow needle to split the tissue
plane & avoid accidental perforation
Allow the needle to stay in the
tissue plane
Most commonly used needle in
squint operation
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43. 43

44.  Needle holders
– Designed for grasping needles during suturing
– Classified --- locking vs non-locking
– It is important to use the needle of the right size to avoid damage to the needle
holder or to the needle itself
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45. – Titanium needle holder:
– This is for fine needle such as 10/0 nylon used in corneal graft or ECCE
– Barrquer needle holder:
– This is a non-locking needle holder and is commonly used in suturing of skin
and for strabismus
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46. – Castroviejo needle holder:
– This needle holder has a locking system allowing a firm grasp of the needle
– Kalt needle holder:
– This needle holder also has a locking mechanism to secure the needle during
suturing
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47.  Ophthalmic Forceps
– Forceps are designed for seizing or holding tissues or sutures
– Different designs of forceps are available in ophthalmic surgery
– Can be broadly divided into two types:
– Toothed --- used for holding tissues
– Smooth --- used for holding and tying sutures
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48. – Ophthalmic forceps has three parts:
– Tips (working ends) --- connected to shaft --- which is connected to handle
– The tip determines the function of the forceps --- may be tooth or smooth
– With tooth forceps, the teeth may be interdigitating or opposing
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49. – Opposing type:
– Causes less trauma to the tissue --- however, provides less fixation
– Interdigitating type:
– The standard interdigitating type for anterior segment surgery is of the one-
into-two pattern
• The teeth may be set at right angle --- Bishop-Harmon
• Forward-angled teeth --- Castroviejo
– The forward-angled forceps allows greater ease in gasping and manipulation
of tissues
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50. – Examples of forceps for different tissues
– Conjunctiva --- Moorfield’s forceps
– Cornea and sclera --- Colibri’s forceps
– Skin --- Adson’s forceps
– Lens capsule --- Utrata’s forceps
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51. Forceps
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52.  Suturing And Knot Tying
– Various suturing and tying techniques are used in wound closure in ophthalmic
surgery
– Suturing can be broadly divided into:
– Interrupted
– Continuous (running)
– Mattress --- horizontal, vertical
– Note that, these naming are not mutually exclusive
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53. – Interrupted Sutures:
– The knots are placed on the sides of the wound to avoid wound depression
– Exceptions --- where depressed wound is desirable
• Upper lid blepharoplasty
• Ptosis operation
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54. – Mattress Sutures:
– These are better than over and over sutures in ensuring eversion of the wound
edge --- however, their removal may be difficult
– Semi-mattress sutures reduce the puncture marks
• But, may not evert the wound effectively
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55. – Continuous Sutures:
– These have the advantage of evenly distributing the wound tension
• However, if they break wound dehiscence can easily occur
• In this respect, interrupted sutures give a better security
– The continuous intracutaneous is ideal for creating inconspicuous wound such
as that in direct brow lift operation
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56. – Common Types --- Overall
– Interrupted over and over
– Interrupted mattress
– Interrupted horizontal mattress
– Interrupted semi-mattress
– Continuous over and over
– Continuous mattress
– Continuous interlocking
– Continuous intracutaneous
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57. • Satisfactory Wound Healing
– For satisfactory wound healing:
– Wound edges are joined loosely --- since there is always some postop swelling
– The wound edge is slightly everted to avoid wound depression
– The tissue is not constricted by suture
– The dead space is closed to reduce the risk of infection, haematoma and wound
depression
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58. – After Care:
– The earlier the sutures are removed the less the likelihood of persistent
puncture marks --- but, the greater the risk of dehiscence
– As approximate guide, sutures on the face should be removed after 5 days
– However, those at the lid margin should be left for at least 10 days --- to avoid
the risk of dehiscence
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59. – Suture Removal:
– Sutures should be removed by pulling it out towards the wound --- as in fig. A
– If pulled out away from the wound, the wound may become dehiscence --- as in
fig. B and C
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60. • Knot Tying
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61.  Basic Instrument Handling
– Correct way of holding instruments:
– For example, the scalpel should be held with the handle rest on the thumb and
index interdigit --- like holding a pen
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The handle should rest on the thumb
and index interdigit
Correct way
Wrong way --- unstable grip

62. – Correct way of holding a needle:
– The needle should be held ⅔ of the way along the shaft from the tip
• Too close to the swage --- make the needle unstable
• Too close to the point --- may not allow enough length for the needle
tip to emerge from the tissue
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63.  Basic Principles Of Eye Surgery --- Pearls
– Skin surgery --- always use LA containing adrenaline
– Give LA 10 minutes before incision --- to allow the adrenaline to achieve its
vasoconstrictive effect --- reduce bleeding
– Only cut if you could see the surgical field
– Blind cutting may produce irregular edge and damage important structures
– Make sure the field is not obscured by blood or shadows, . . .
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64. – Cut under tension and suture without tension
– Cutting without tension --- can cause irregular wound
– Suture under tension --- increases scar, and possibly, wound dehiscence
– The scar from excising a skin lesion will always be longer than the lesion itself
– Always discuss this with the patient preoperatively --- to reduce patient’s
dissatisfaction
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65. – Avoid extending incision outside the periorbital region to reduce scar
– The thicker skin outside the periorbital region tends to give more prominent
scar than the thinner periorbital region
– Do not excise any lacerated periorbital skin during primary repair --- unless it is
necrotic
– The skin on the face has good blood supply and often survive despite extensive
laceration
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66. – Send all excised lesion for histology --- even if it appears benign
– Histology of seemingly benign lesion can yield surprises
– Cases of metastasis or sebaceous cell carcinoma may appear benign clinically
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67. Thank Eye!
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