Principles of Microsurgery

Basics of microsurgery with caveats of good anastamosis and post operative monitoring holds key for present day plastic surgery

1. DR G AVINASH RAO FELLOW IN HAND & MICROSURGERY SKIMS, SRINAGAR PRINCIPLES OF MICROSURGERY

2. Microsurgery Definition Surgery utilizing magnification and small, handheld instruments and suture s to correct defects in small &/or delicate tissues

3. INTRODUCTION   Two main purposes of microsurgery are to transplant tissue from one part of the body to another and to reattach amputated parts . It is incorrect to state that microsugery is simply a general term for surgery requiring an operating microscope It is based on the fact that the human hand, by appropriate training, is capable of performing finer movements than the naked eye is able to see. Magnification is a tool to lessen the effects of compromise in treatment modalities The term MICROVASCULAR SURGERY was coined by JACOBSON Super Microsurgery is defined as microsurgery in less than 0.8 mm vessels .

4. Microsurgical techniques include nerve and blood vessel repairs and grafts, free tissue transfers, limb replantation , and composite tissue allotransplantation . Technical expertise, Preoperative planning and Post-Operative monitoring are also critical in achieving a successful microsurgical reconstruction.

5. HISTORY 1590- Invention of compound microscope by Zacharia Janseen 1889- First successful end-to-end arterial anastomosis by Jassinowski   in sheep. 1897- First vascular anastomosis by J.B.Murphy in humans 1902- End to end anastomosis by 3-stay suture technique by Alexis Carrel . 1965- First digital replantation by Tamai 1968- First successful toe to thumb transfer by Cobbett

6. Guthrie and Carrel - inclusion of the INTIMA in repair laid the foundations for standardization of anastomotic techniques. 1912 - Carrel – (Nobel Prize in Medicine and Physiology), First described the technique of placing triangulating sutures to ensure equal traction on the blood vessels being anastomosed . 1968- First free flap in Bombay,India by Antia and Buch ( Use of dermatolipomatous groin flap to fill a facial defect) . 1970- First completely successful free flap operation in Oakland,California by Mclean and Buncke . 1973- First composite flap (groin flap) by Daniel .

7. PRINCIPLES OF MICROSURGERY As a treatment philosophy, microsurgery incorporates three important principles: 1.Improvement of motor skills , thereby enhancing surgical ability. 2.An emphasis on passive wound closure with exact primary apposition of the wound edge. 3.The application of microsurgical instrumentation and suturing to reduce tissue trauma.

8. MICROSURGICAL TRIAD

9. To do a job….you need the right tools

10. Microsurgery Differs from traditional surgery in: Surgeon position Magnification Specialized instr u ment a tion Suture and needle size

11. EQUIPMENT FOR MICROSURGERY Good quality instruments – prefer own instruments Old wornout , battered instruments – not even suitable for Lab training. Spring tension – appropriate. Weak – closes early – hold the instrument gently with tips 1-2mm apart and pronate forearm such that instrument is upside down – falls down. Firm – fatigue of thumb muscles – hold the instrument gently closed for 10 min.

12. Jewellers forceps Straight pointed no.3 – non dominant hand for tissue handling and suture tying. Tip precision – 1/1000 = diameter of 10.0 Nylon. Jaws should meet over 3mm (not only at tip)– easy thread pickup

13. Angled jewellers forceps Reaching under vessel, tying knots, doing patency test. Rest same as straight jewellers .

14. Needle holder Round handled, fine, fully curved jaws with a lock. Look for open gap at the at the point jaws closes completely – thread traps.

15. Vessel dilator Modified jewellers forceps Slender, smoothly polished, non-tapering tip. Used for dilating vessel, counter pressure for suturing.

16. Dissecting scissors Spring handled with gently curved blades, lightly round at the tips. Rounded tips are important – enable to dissect closely along a vessel with out perforating it,

17. Adventitia scissors Trimming adventitia off the vessel end. A pair of Fine straight, sharp pointed tip microscissors .

18. Vessel clamps Collection of clamps required. One comparatively large sliding approximator clamp with built in suture holding frame. A smaller plain approximator clamp Two small single clamps – small gentle jaws. Larger – 11mm – harmless on vessels between 1.5 and 0.7 mm diameter Smaller – 8mm – less closing force for vessels between 1.0 and 0.4mm. Clamp applicator forceps.

19. Closing pressure ( gms ), area of vessel wall compressed by clamp (mm 2 ) Good clamp – Recommended closing pressure – 5-10gm/mm 2 – large vessels and 15-20 gm/mm 2 on smaller vessels. For every vessel there will be two suitable clamp sizes – smaller clamp is recommended to use.

20. Non microsurgical instruments. Autoclavable Instrument case. Hemolytic emzyme solution – contact time of 30 min - best to clean microinstruments . Small fine flat jawed pliers – minor adjustments tip of jewellers . Instrument demagnetizer – simple hollow electric coil connected to the regular AC supply – place instrument inside – swith on current – slowly withdraw till it is 60cm away- then swit Sutures – flat bodied microvascular needles on 10.0 nylon. ch off current. 100 microns needle – basic exercise. 75 microns needle for advanced exercise. AVOID round bodied needles – difficult to control.

21. Magnification OPERATING MICROSCOPE MAGNIFICATION LOUPES-

22. Microscope Zeiss – Good Optics. Best focal length for objective lens is 200mm for normal height, 300mm for very tall persons for better working position Best eyepiece magnification is 12.5X. 200mm + 12.5X gives magnification range between 4 to 20. Full floor column, adjustable supprt arm, foot controls, inclinable eyepiece – in newer scopes – required. Floor mounted / Ceiling mounted / Table mounted / Portable

23. Care of microscope Clean outer glass surface of eyepiece and objective lens each time – with lens tissue. Cover after use. Careful handling while moving.

24. Optical head has Primary surgeon Beam splitter Assistant surgeon Video attachment

25. OPERATING MICROSCOPE - Features Coaxial illumination . variable magnification motorized continuous zoom motorized focus motorized X-Y axis Foot controls adjust light , magnification, zoom, focus and X-Y axis Allow multiple surgeons Floor, table or ceiling mount Additional attachments

26. Operating Microscope magnification from 5-40x magnification of 5-20x is generally sufficient. Increased cost and maintenance longer surgical setup time less intraoperative positioning flexibility less portability

27. Center the X-Y axis Lowest magnification, Zero the fine focus. Adjust the gross focus manually Adjust the interpupillary distance Adjust the chair and table height Ensure the surgeons view and the video view are both in focus Verify at the highest magnification to be used. Position all foot pedals where they can be reached M icroscope pedal goes to the non- dominant foot Know Where All The Foot Pedal Controls Are Before Starting Surgery When seated, adjust gross focus by hand, not foot pedal. Prior to surgery

28. Surgeon is seated comfortably Feet reach the pedals Back is straight Arms at 90 degrees Lean slightly forward Arms on armrests Hands positioned and supported Rest on the ball of the hand or extend 5 th finger for support Turn off room light and on microscope light AT THE START OF SURGERY

29. Adjust table height Adjust chair height Adjust microscope height Adjust chair arm rest position Set microscope fine focus to neutral Center X-Y axis Adjust microscope tilt Adjust interpupillary distance Set microscope to highest magnification to be used Adjust focus of oculars Ensure video and assistant images are also in focus Return microscope to low magnification Place foot pedals to be comfortably accessible PREOP CHECK LIST

30. Surgeon Position Surgical Position Seated Specialized chairs with armrests Arms resting on armrest Essential for fine motor control

31. Surgical Position Seated Specialized chairs with armrests Arms resting on table or armrest Essential for fine motor control Able to adjust height

32. Positioning of hand Arm - Rested, Elbow, Wrist, Ulnar border of hand on table, forearm supinated a little. Three digit grip – IF, THUMB, MF. MF – rest firmly on the working surface either directly or via RF. PULP TO PULP PINCH

33. Instrument Handling Delicate, precise movements Finger movements only Pencil grip Arms on arm rests Elbows and wrists locked

34. Simple Loupes one pair of positive meniscus lenses limited by spherical aberration and color fringing plastic construction fixed interpupillary distance very short working distance poor surgeon body and arm position strain on the surgeon’s neck and back. POOR CHOICE

35. up to 2.5x magnification multiple lenses to offer magnification and are generally lightweight and less expensive adjustable interpupillary distance working distance varies Galilean Loupes

36. up to 8.0x magnification ≥5.0x a microscope is preferred highest optical quality series of lenses and prisms to magnify the subject similar in principle to low-power telescopes greater magnification sharp resolution greater depth of field heavier and more expensive Prismatic Loupes As magnification increases they become long and heavy Shallow depth of field Head movements make use difficult (>5X)

37. P rovide an improved view of the tissues of concern Will vary by tissue of interest A llow a comfortable working distance for the surgeon Back straight, arms at 90 degrees F acilitate adjustment of the interpupillary distance to suit the surgeon P ermit a wide field of view Magnification – purpose:

38. AS MAGNIFICATION INCREASES The field of view and depth of field decrease At 3.5X - field of view is 50mm and depth of field is 2.6mm At 20X - field of view is 10mm and depth of field is 0.4mm

39. Magnification Beginning surgeons should start with magnification early as part of their basic training Will improve their tissue handling and appreciation for tissue trauma and wound apposition

40. FIRST THING FIRST – PRECONDITIONS FOR SUCCESS Uninteruppted Surgical training. Adequate sleep. Diengage from Clock and Telephone. NO MAGIC for success – dedicated Practice – as Margin of error is measured in thousandths of an inch. If Some thing is wrong – Donot Struggle ON – Figureout First and then Proceed. Avoid Cigarette Smoking, Coffee before Surgery, Strenous manual exertion like weight lifting / playing tennis etc (Causes tremors). Take a Break – When the advise is given – not to resist it.

41. Surgeons must have a plan t o achieve the goal , B ut must also be adaptable and familiar with more than one technique , so that obstacles encountered during the surgical procedure may be overcome.

42. Not all surgeries proceed according to the plan. We may all travel a different route and method. We get there in various ways , BUT…..we all get to the SAME DESTINATION

43. Regardless of our individual variations, we must all follow the BASIC RULES : To Use Appropriate Magnification And Instrumentation To Be Efficient And Precise To Ensure Minimal Tissue Trauma To Minimize Surgical Time To Obtain Excellent Tissue Wound Apposition With The Smallest And Most Appropriate Suture Materials To Achieve A Successful, Comfortable, Cosmetic Outcome

44. EXIT PUPIL – OPTICAL AXIS

45. Exit pupil Lies in mid air at short distance of 15mm from eye piece. Diameter of exit pupil is 2mm and pupil in normal light condition is 3mm. The exit pupil must sit right in the middle of the hole in iris, that is pupil – for circular field of vision. Movements even by a millimeter changes circular field to eclipse. Position eyepiece at 50 angle to the horizontal for better longterm comfort. (very tall near to 60, very small near to 40)

46. Handling needle holder and suture Lift thread with forceps in left hand till the needle dangles and just rest on surface – rotate thread accordingly to position needle direction. Needle is to be setup at 90 to the needle holder tip. Needle tip should point horizontally not up / not down – hold at the middle of needle. Needle holder is held with tip pointing away – towards left for right handed.

47. Passing Needle through the tissue Needle should pass perpendicular to tissue surface. Evert tissue edge before passing needle – place forceps underneath, near to the needle placement and evert tissue – never grab full thickness. Needle should come out of the other side perpendicularly – counter press to the needle is given from outside side with forceps near the exit point. Width of bite from tissue edge – 3 times the thickness of needle. Pull thread in straight line, drop the needle. Short end of thread should be at least 3mm.

48. Knot tying Pick the long thread with left hand forceps. Turning it into loop over needle holder. Now Picking up short end. Completing first half knot Then second half knot Use third extra half knot also for safety. Cut short end first and discard it. Then hold long end and cut it after needle come in view. Surgeons knot with a double throw – overcomes natural elastic retraction of tissue (Tension free repair).

49. MICRO VASCULAR SURGERY 1. Gentle handling of tissues *Avoid grasping the ends of the vessels to be anastomosed *Grasp only a small qu a ntity of loose periadventitia

50. 2. ADEQUATE DEBRIDEMENT Inspect under high power for signs of damage Debride until no signs of vessel damage Strong pulsatile flow of blood after adequate debridement

51. 3. SPASM Trauma is blamed for the reason of spasm Two main factors for spasm - cold - contact of outside wall of vessel with freshly shed blood

52. RELIEF OF SPASM Mechanical dilatation Hydrodistention of the vein graft Moist gauge soaked in warm saline 1% lignocaine spray – contact time 3 min – after dilation wash with RL

53. 4. SIMILAR DIAMETER OF VESSELS Vessels with d issimilar diameter of upto 50% can be anastamosed satisfactorily

54. Small vessel is dilated and divided obliquely (not >30 to give adequate symmetry When the size discrepancy is much greater, an interposing vein graft is used

55. 5. TENSION-FREE ANASTOMOSIS Apply an adjustable approximating clamp to bring the vessel end together for convenient suturing Never apply clamp with excess tension Avoid any kinking or twisting of the vessels distal to the anastomosis Avoid inverting cut end of vessel wall during anastamosis - THROMBOGENIC

56. 6. CORRECT SUTURE TENSION Not too tight or too loose sutures Too tight sutures Avo ided by a small “suture circle ” at the end of three ties .

57. APPROPRIATE SUTURE SPACING: -Goal is to achieve an ultimately leak - free anastomosis with as few sutures as possible RECHEK OF ANASTOMOSIS: -All anastomosis are rechecked prior to the final skin closure

58. 8 CHOICE OF RECIPIENT VESSELS Use of healthy vessel of reasonable size with good outflow is the key for success Pre-operative assessment - caliber and injury during dissection. Mobilisation of v e ssels – for tension free repair.

59. DISSECTION TECHNIQUES Hemostasis – must * Torniquet *Vascular clips *Bipolar coagulator Avoid perivascular hematoma Irrigation – moisten tissue every few minutes with RL, mop excess with sponge.

60. Avoid damage – on dissection DONOT - work in a field obscured by blood. - work out of focus. - cut when you cant see. - hold scissors at wrong angle. - grab full thickness of vessel wall. Grab vessel with its outer layer – adventitia Divide adhesions b/w adventitia and vessel wall – tease the adventitia before cutting with round microscissors – to see cut end of tunica media. Cauterize any branching of vessel with bipolar at a distance away from main vessel.

61. Preparing the vessel ends Get the blood out – RL Flushes Remove the adventitia – to see media. Dilate vessel ends – relieve spasm. And to handle easily during repair. This will determine the quality of anastamosis to a larger extent

62. Background – 1mm Grid Lines - Provides an accurate measuring tool for the surgeon Available in Blue , Green or Yellow - Best contrast Non-Reflective Surface - Eliminates glare from OR lighting Radiopaque Silicone Material - Can be seen under X-Ray if needed

63. TECHNIQUE OF ANASTOMOSIS - 1.Resection to normal vessels: Resect proximal to areas with microscopic signs of vessel damage with fine, straight, sharp scissors in a single motion

64. Demonstration of forward pulsatile flow prior to clamping

65. Clamping of vessels: With double approximating clamp leaving generous length of vessel end for ease of working Tips of the jaws should project just beyond the vessel for maximal grip

66. Incorrect vertical position

67. Incorrect horizontal position

68. 3. Positioning: -Correct position of the clamp is horizontal and parallel to the operator

69. 4. Final Preparation of vessel ends: nd Resect sufficient periadventitia, flush with the underlying vessel to expose 2-3 mm of the vessel wall for suturing

70. If the lumen is small or in spasm, gently dilate it with vessel dilator dr sumer yadav (mch n d n s t r u ct i v e

71. Irrigate the lumen with solution of heparinized saline ( 1000 units per 100 ml) .

72. 5. SUTURING End to end / End to side - depending on type of anastamosis Full thickness of wall Size of the suture material – 10.0 Nylon Number of sutures – 8 stiches for 0.7 – 2 mm vessel diameter sufficient Distance between sutures – equidistant – good enough to prevent leak. Arteries- more sutures than veins

73. Pass the needle at right angles to the wall at a distance from the margin slightly greater ( 1-2 times for arteries, 2-3 times for veins) than the thickness of the vessel wall

74. Make sure that the posterior wall is not accidentally cought For last 2-3 sutures : Modified Har a shina technique

75. For thick walled arteries and large diameter collapsible veins- use 180 degree halving method ( first suture at 150 degree position and second suture at -30 degree

76. For thin walled vessels, use 120 degree triangulating method for key sutures (First suture at 150 degree position and second suture at +30 degree position)

77. 6.RELEASE OF CLAMPS The distal clamp is released first If any major leak, reapply the clamp, irrigate and insert additional superficial thickness sutures Now release both the clamps- usually small amount of blood leaks from anastomosis, but stops after a few min. with the application of sponges

78. VENOUS ANASTOMOSIS Veins are thinner, flatter and more difficult to anastomose Use ringer’s solution to float or irrigate the vessel Deeper bites More sutures

79. ALTERNATIVE ANASTOMOSIS TECHNIQUES 1. BACK-WALL FIRST ( ONE-WAY UP) TECHNIQUE -This technique is safest because the entire inside of the anastomosis can be visualized until the very last few sutures are placed

80. 2. FLIPPING TECHNIQUE When free flap, digit or vein graft is fixed fo mobile vessel, it can be flipped to expose the back-wall for repair , a s rotation is not possible

81. 3. CONTINUOUS SUTURING Acceptable patency rates ( 92% for arteries, 84% for veins) comparable with interrupted sutures Advantages: Quicker and more hemostatic Disadvantages: * Potential for creating purse-string constriction at the site of anastomosis * Entrapment of the suture material in the clamp * Breakage of the suture So less favourable

82. 4. SLEEVE ANASTOMOSIS Microanastomosis of vessels in 1 mm external diameter range can be accomplished by means of invaginating technique with fewer sutures than the end to end method of closure

83. Advantages: Quicker Less intraluminal suture exposure Less vessel trauma owing to fewer sutures Disadvantages: Patency rate is significantly less than that achieved by the conventional end to end method, so it is not superior in clinical situations

84. END TO SIDE ANASTOMOSIS Indications: *To preserve patency of the recipient vessel in lower limb,esp. in elderly patients, where sacrifice of a major vessel can have a serious effect on the distal blood flow *Considerable size or wall thickness , mismatch between the vessels

85. Steps of end to side anastomosis

86. Advantages: Search for recipient arteries is simplified No. of possible sites to which free flaps can be transferred is greatly increased

87. Signs of Patency Expansile pulsations – increase and decrease in diameter of vessel distally with each pulsation – patent Wriggling – change in curvature of vessel distally with each beat – patent Longitudinal pulsations – conentrared over particular point – along long axis – hammering against a partial / complete block False wriggling can be seen with longitudinal pulsations – lift anastamotic site with suture thread.

88. PA T E N C Y Return of colour Capillary oozing and venous bleeding from the revascularized tissue Direct inspection under the microscope Uplift test & Empty and Refill test

89. Uplift test

90. Empty & Refill test This is traumatic and is performed as gently and infrequently as possible

91. Modified Uplift test – Vein patency Curved forceps beneath vein distal to anastamosis – lift it up till occluded – move it along proximal in downstream direction – going past anastamotic site. Patent – vessel fills up behind moving instrument. Blocked – distally dilated with negative filling test & with time blood in vein becomes dark.

92. Practical points on blood. Undamaged vessel wall secretes anticoagulants – so uncontaminated blood in undamaged vessel remain liquid for several hours. Blood inside a vessel will not clot unless – the vessel is damaged / blood contaminated with thromboplastins Blood that is in open contact with the wound should never be allowed to stand still in a vessel unless heparinized irrigation fluid is present. Wise to leave the vessel alone and run for 20 min – after dissection & 20 min after anastamosis .

93. ANASTOMOTIC FAILURE A) TECHNICAL ERRORS: Tearing Leaking Narrowing Through-stitching Inclusion of adventitia B) Poor flow from proximal vessel due to undetected damage more proximally or vasospasm

94. C) A clot or thrombus at the anastomotic site or in an area where a clamp was applied - Damage to endothelium from + Excessive clamp pressure + Poor technique or + Contamination Prevention: + Flushing of the suture line with heparinized solution + Systemic heparin (40 u/kg before completion of anastomosis and release of clamps)

95. REVISION OF THE FAILED ANASTOMOSIS If the patency test reveals slow filling of the distal vessel, revise the anastomosis, carefully keeping original problem in mind Insert a vein graft, if the vessel length is insufficient

96. *Poor proximal flow that does not respond to local vasodilator and warming may require: Proximal exploration of the vessel Dilatation along a proximal length of vessel sufficient to relieve vasospasm

97. FACTORS INFLUENCING FAILURE OF ANASTOMOSIS A. TECHNICAL: Both walls sutured together Traumatic vessel handling Apposition of vessel edges Disproportional vessel size Tension at suture line Excessive clamp pressure Kinking of vessels

98. B. REPERFUSION FAILURE : Blood turbulence Spasm Hypercoagulability Acidosis Cold Hypovolemia Vasoconstrictors

99. C. POSTOPERATIVE CARE: Infection Acidosis Col d Limb position Environmental factors

100. POST-OPERATIVE MEASURES Oxygen administation Bed rest or limited movements for 3 to 5 days Warm room Limb elevation to decrease the venous congestion Fluid administration Pharmaotherapy – anticoagulants

101. Adequate analgesia Limitation of visitors and telephone calls to decrease the emotional stress Prohibition of smoking, caffeine and chocolate because they may cause vasoconstriction