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Opththalmic Microsurgery.pptx
- 1. Basics of Ophthalmic Microsurgery BySagni Jelkeba (MD) Ophthalmologist 1
- 2. Objectives – Atthe 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 2
- 3. Outlines – Introduction –Peculiarities of Microsurgery – Ophthalmic Incisions --- definition, dynamics of incision, cutting instruments – Blades used in Ophthalmic Surgery – Techniques to open Anterior Chamber 3
- 4. – Principles ofWound Closure – Suture materials and Needles – Needle holders – Ophthalmic forceps – Common knotting techniques – Basic instrument handling – Pearls of Eye surgery – Summary 4
- 5. Introduction – Inany 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 5
- 6. – Similarly, poorwound 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 6
- 7. – One thingto 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 7
- 8. Peculiarities ofMicrosurgery – 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 8
- 9. – The operatingmicroscope 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 9
- 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 10
- 11. – Section: – Theresult 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 11
- 12. • Dynamics ofIncision – 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 12
- 13. – Thus, parametersof incision depends on 3 main variables – Characteristics of the cutting instrument – Characteristics of the tissue – Surgeon’s guidance of the instrument 13
- 14. Characteristics ofcutting 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 14
- 15. – Shape ofthe 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 15
- 16. Characteristics ofthe tissue – The sectility of tissues is determined by: – The compactness and strength of its fibers – Their tension --- a taut tissue is more sectile 16
- 17. The Surgeon’sIntervention – 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 17
- 18. Blades Usedin 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 18
- 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 19
- 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 20
- 21. – No.15 Blade –Character --- rounded contour – Used for cutting skin, mucosa, sclera • As in blepharoplasty, skin excision, scleral incision, . . . 21
- 22. Techniques forOpening 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 22
- 23. Principles ofWound 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 23
- 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 24
- 25. – The lengthof 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) 25
- 26. – Criteria forideal 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 26
- 27. – Sutures areclassified 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 27
- 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 28
- 29. 29 Absorbable Sutures Materials Polyglactin910 (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 30
- 31. – Advantages ofmonofilament 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 31
- 32. – Advantages ofmultifilament 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 32
- 33. • Commonly UsedSuture 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 33
- 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 34
- 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 35
- 36. – Polyester andPolypropylene: • 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 36
- 37. Suture Needles –Suture needle has 3 parts: – Swage (connection point for the suture) – The body – Point – All needles are made of stainless steel 37
- 38. – The 5geometries 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 38
- 39. – Shapes ofcurvatures of the needles – ⅛ circle, ¼ circle, ⅜ circle, ½ circle, ⅝ circle – Bi-curve, compound curve, straight 39
- 40. – Ideal sutureneedles 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 40
- 41. • Common SutureNeedles 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 41
- 42. Point Cutting Reversecutting 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 42
- 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 44
- 45. – Titanium needleholder: – 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 45
- 46. – Castroviejo needleholder: – 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 46
- 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 47
- 48. – Ophthalmic forcepshas 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 48
- 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 49
- 50. – Examples offorceps for different tissues – Conjunctiva --- Moorfield’s forceps – Cornea and sclera --- Colibri’s forceps – Skin --- Adson’s forceps – Lens capsule --- Utrata’s forceps 50
- 51.
- 52. Suturing AndKnot 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 52
- 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 53
- 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 54
- 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 55
- 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 56
- 57. • Satisfactory WoundHealing – 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 57
- 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 58
- 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 59
- 60.
- 61. Basic InstrumentHandling – 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 61 The handle should rest on the thumb and index interdigit Correct way Wrong way --- unstable grip
- 62. – Correct wayof 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 62
- 63. Basic PrinciplesOf 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, . . . 63
- 64. – Cut undertension 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 64
- 65. – Avoid extendingincision 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 65
- 66. – Send allexcised 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 66
- 67.