Micro incision vitrectomy surgery

1. Dr. Anuraag Singh
08-09-2018

2. • Surgery to remove some or all of the vitreous humor from the eye
• Anterior vitrectomy
• Parsplana vitrectomy
• Kasner(1962)- OpenSkyApproach
• RobertMachmer - a17-gauge VISC(1971),through small opening in parsplana
- “father of modern vitreoussurgery”
• ConnorO’Malley(1975) –Splitfunctionsystem(conventional) 20-gauge
“bimanual” vitrectomy using 3ports

3. • Chen(1996)- self-sealing suturelesssclerotomy for the20-gauge
• Eugenede Juan(1990)- invented the 25-gaugewith transconjunctival
sutureless vitrectomy (TSV)
• Eckardt- a23-gauge system& Oshimaet al – a27-gauge system

4. • The20 G- considered the “gold standard” since1974
• First complete 23 G- introduced (2005) & judged to be safe&efficient
• The23 G- combines the benefits of the 25 G& 20G
• 23 G- potential to become the future “goldstandard”

5. 20 G 23 G 25 G
1) Size 0.9 mm 0.7 mm 0.5 mm
2)Need for suture Yes No literature data No
3) Angled instruments Yes No literature data No
4) Instr. Stiffness (grams
per 4 mm)
130 g 35 g 14 g
5) Intraocular maneuvers Easy Easy Not Easy
6) Flow rate High High Low
7) Oil injection Easy,all oilviscosities Slow, all oil viscosities Very slow, only 1,000 cS
8) Vitrectomy time Fast Fast Slow
9) Post-op inflammation Yes Poor Poor
10) Post-op astigmatism Yes No No
11) Riskof post-op hypotony No No literature data Low
12) Riskof endophthalmitis Very Low No literature data No literature data

6. 13) Useof fragmetome Yes No No
14) Changeof cannulaposition Cumbersome Easy Easy
15) Vitreous incarceration No Possible Possible
16) Endo-illumination Good Good Good with chandelier
17) Oil removal Fast Slow Very Slow
18) Useof endolaser Yes Yes Yes
19) Vitrector cutting rate Up to 2,500cpm Up to 2,500cpm Up to 1,500cpm
20)Current Indications still better for thetreatment treatment of MH treatment of all
of eyeswith (ovelapping with 25G), macular pathologies e.g
poor visual prognosis, complicated retinal MH,ERM,vitreous opacity,
such as detachment requiring mild vitreous hemorrhage,
advanced PVR standard or heavysilicone proliferative diabetic
and severe trauma oil endotamponade, retinopathy
for complications and cataract surgery
of severediabetic complications
retinopathy
And in Topicalanaesthesia

7. • SizeOFCutter – Rigidity of 23 Gvitrectome is below that of a20-
gauge,but is double that of a 25-gauge.
The23 Gentry port
– closer to the tip
of Instrument than
20- or 25G

8. • MicrocannulaSystem -
Entry SiteAlignment system(ESA)is the key to 25-gauge instrumentation
TheESAsystemcomponents include: the 25-gauge trocar-mounted
microcannulas, cannula plugs, and infusion line
Microcannula consist of two components – Polyimide cannula & polymer
cannula hub with distal end cut by 30 degreeangle

9. • 23 GTrocar–solid stiletto with atrapezoidal cutting section & acutting diameter of 0.74 mm
compared with 0.61 mm for the 25 G
• Length of the stiletto is 9.6 mm compared with 9 mm for the 25 G.
• Thetrocar is in titanium & not in polyamide asis the casefor the 25 GSubdivided - part out of
thesclera, block length 1.5 mm,& abulbar part of 4 mm compared with 3.51 mm in the 25-
gauge,facilitates asaferoblique insertion.

10. • SomeSystemcontain Integrated Scleral Marker
•T/CDelta –Diff between Outer Diaof Trochar& Inner DiaofCannula.
•Onemetric that impacts cannula insertion into Trocarwound, aswell asCannula
performance
•Alarge T/Cdelta –risk of tissue caught between Trochar& Cannula
•Too Small T/Cdelta –Removal of Trochar could be difficult & inadvertent cannula
removal

11. • Infusion cannulahasan internal diameter of 0.56 mm in
23 G
& 0.42 mm in the 25G
• Infusion line hasafemale Luer-lock connector for precise sliding fit within
the microcannula

12. • Flow Rate - Diameter – critical changesat Infusion line &Aspiration tip
• Soinfusion pressure of 30-40 mmHg in 20 Gto 40-50 mmHg in 25G(50-60
during Dynamic state & 35-45 during Staticstate)
• AlsoAspiration Vaccumraises as150 in 20 Gto 250 & 500 mmHgin 23 & 25G
• Port Basedflow limiting advantagenous in High cutter rates & 25Gby increasing
fluidic Stability & reducing cutter induced motion of detached Retina

13. - Differences between 20,23,25 GVitrectome
• Duty Cycle- %of time port open in entire cycle of cutter

14. • Illumination System–Consist of Five
basic buildingblocks
• Efficiency of the illumination system - depends on its coupling efficiency
(measureof the power emitted from the optical source coupled into the
fiber)
• HIDlamps - metal halide and highpressure sodium
• Xenon lamps currently in Accurus SystemfromAlcon

15. • Reducingthe diameter of alight pipe by 20%theoretically reducesthe amount of
illumination by∼35%
• Wide-angle diffuse illumination preferred - visualizing transparent ILM,clear vitreous, and
“glassy” epiretinal membranes
• Colorlesstissue best seenwith white light
• Brighter light, xenon & mercury vapor improve visualization withsmall fibers
• TwoCategoriesof Fibres used1) Glassfibre , 2) Plastic ( PMMA)

16. Chandelier-style illuminator –To permit 4-port Vitrectomy for Bimanual
Surgery
- Its handsfree & self-retainingdesign
25 GChandelinear style endoilluminator compatible with Xenon
1) tipfor trans-scleral insertion 2) for insertion through transscleral
microcannula

17. • In addition to the chandelier systems, another
exciting new advance is acombined fiber optic
light/laser probe made by Synergetics in 25Gsurgery
• Allow to usethe laser andlight simultaneously
1)Endoilluminator
Wide Field
monofiber for
Scissors/Forceps

18. • 25-gaugeinstruments –
a)Tanoasymmetric micro forceps for ERMorILM
peeling
b)Eckardt micro forceps for epiretinal ERMor
ILM peeling
c) Vertical scissorsfor membrane dissection
d) Silicone-tipped backflash brush needle
e)Diamond-dusted membrane scraper for
removal of PVD
f) RiceILM elevator for ILM peeling orposterior
vitreous hyaloid separation
g) Extendable endo-laser probe

19. • 23-gaugeinstruments –
23Gtrocar kit

21. • Visualization–Wide-angle( Panoramic) viewing System
-For removing peripheral VRTin rhegmatogenous RD,PVR,
andgiant breakcases
-Decreaseslateral and axial (depth) resolution soshould not be
usedfor macular surgery or most diabetic tractionRD
• Most surgeon prefer (Lander’s) Contactlensfor Macular Surgery
• Contactbasedwide-anglesystems,haveagreater field of view than non-contact
systems,eliminate cornealasphericity
• Wide-angle View reduces need for turning eyeball sobenefit flexible tool of 25G

22. • CutRate –
-High CPMsafer than Low CPMin Vitrectomy
- Low CPMtraction on Vitreous & Retina
- High CPMenable to work close to retinawithiatrogenic breaks
- ‘Shaving Mode’ canbe used with Low Suction & HighCPM

23. • Port Location–
Port Closer to Tip of shaft permits to cut membranes very close to
retinal surface
Reducing dependence on scissorsduring Vitrectomy for PVR
20 G 23 G 25 G
Port Distance to end 0.457 mm 0.229 mm 0.356 mm
Port Area (mm2) 0.254 0.183 0.083

24. • Cannulawith Valves– Prevent leakage of fluid when instrument removed
Maintain IOP& avoid Hypotony related complication
Require precaution in injecting SiliconOil
Valvecannula (DORC).Acap-like silicone membrane is mounted on the head of the microcannula. Aslot in the
membrane allows the insertion ofinstruments

25. • Sclerotomies– 4.0 mm posterior to thelimbus
- Positions :
- Inferotemporal - Justbelow 3 or 9 O’clock meridian awayfromlower
- eyelid aspossible, For infusion microcannula
- Superonasal - on virtual line from the lowest point of the bridge of the nose
extending through the center of the pupil
- Superotemporal - virtual line extending from the lowest point of the
supraorbital rim through the center if the pupil
- Methods : Transconjunctival Oblique-parallel Scleral tunnel incision is favoured

28. • CannulaRemoval– Before removal, always clear the cannulas from inside
Clamp the infusion cannula before removing instruments
Pressand Massagethe sclera with acotton tip to closewound
Raiseinfusion pressure to 25–30 mmHGto checksclerotomy
airtight
If Pressuredrop,perform an air or BSSrefilling with 30Gneedle
Leakagepersists,suture the sclerotomy
CheckIOPin early postoperative period (about 6 h p.o)

29. • Advantage of MIVS –
• Reducedthe risk of retinal breaks related tosclerotomy
• Relative lack of conjunctivalScarring
• 20 GPPVtotal sclerotomy 3mm Vs1.5mm in 25 GPPV
• Low patient Discomfort
• Better & sooner Vision recovery time d/tlessinduced astigmatism & tear film
disturbance
• Lessvitreous removal in 25 Gmay protection for cataract rate after vitrectomy (
diabetic vitrectomy <Epimacular memb vitrectomy)
• Benefits in “Shaving” off retinal surface & cutting of “Pegs”
• ComboSurgery in Presbyopic patients

30. •Indication of MIVS –
Posterior hyaloid
Peeling in PDRcanbe
Done by 3 approach
with by bimanual
maneuver as
1)Segmentation
2)Delamination
3)en-Block dissection
1) Macular diseases- — Epiretinal membrane proliferation
—Idiopathic or secondarymacularhole
—Macular tractionsyndrome
—Macular edemaassociated with
- diabetic retinopathy
- retinal veinocclusion
- uveitis
—Persistentpseudophakiccystoidmacular edema
—Submacularhaemorrhage
2) Simple vitreous haemorrhage, Persistent Vitreous Floators
3) Vitreous biopsy
4) Primary rhegmatogenous retinal detachment
5) Proliferative diabetic retinopathy with or withouttractional
retinal detachment, Nonclearing VH& eye with refractory CSDME(NPDR)
6) Dislocated crystalline lens fragment

31. Adult Pediatric( Forprimary postpole disease)
ERMPeel Zone1 ROPwith low lyingRD
Macular Hole Vitreous hemorrhage
Posteriorly Subluxed Lens Cataract extraction
Tractional RD Endophthalmitis
Silicone Oil Injection ERMPeel
Vitreous Hemorrhage Traumatic Paediatric Macular hole
Rhegatogenous RD Persistent fetal vasculature ( wherein PPis well formed)
Uveal/ Vitreous Biopsy Retained lens fragments
IOFBRemoval FEVR
Endophthalmitis Paediatric macular pucker ( Combined Hamartoma)

32. • Advantagesof small-gaugevitrectomyoverscleral buckle
• Lesstrauma to the conjunctiva and sclera, no need for conjunctivalperitomy
• No manipulation of extraocular muscles,therefore lessrisk ofpostoperative strabismus
• None of the risks of draining subretinal fluid through the sclera Noeffects on refraction
• Better control of intraoperativetone
• Elimination of vitreous traction and opacity,with lessrisk of macularpucker
• Disadvantagesof smallgaugevitrectomycomparedto scleralbuckle:
Greater risk of cataract
Greater risk of PVR(though not yetdemonstrated) More
costly materials

33. • ComplicatedRhegmatogenousRetinal Detachment
23-gaugevitrectomy is better than 25-gaugeforcomplicated RD
1) Advantages of 23-gaugeover 20-gaugevitrectomy for complicatedRD: Less
trauma to the conjunctiva andsclera
Better stabilization of the detached retina becauseof the smaller vitrectome mouth
Thepossibility of shifting the position of the instruments and the infusion cannula,
for an easier approach tothe superior sectors
2) Disadvantagesof 23-gaugecompared to 20-gaugevitrectomy for complicated RD:
Vitrectomy times arelonger
Difficult to inject high-viscosity silicone oil, if needed, becauseof the sizeof the cannula
Impossible to usean angledinstrument
More costlymaterials

34. • Limitation Of MIVS –
Hard dislocated cataractous lens would need a20 G
Fragematome
SevereDiabetic Retinopathies & extensive tractionor
combined RD
Silicon oil injection ,but with use of machine injectors, even 5000
centistokes oil canbe injected through fineport
Evenwith MIVS,sclerotomies suture in caseof silicon oil inj

35. • ProblemWith MIVS –
• Unsutured infusion cannula –
• Riskof Cannula Slipping especially in eye with deep orbitalsocket
Complication causedwill depend on Infusate as–
A)With Fluid – SerousChoroidal Detachment
B)With Air – Subretinal air, Suprachoroidal air,
Suprachoroidal Haemorrhage
C)Accidental Withdrawal of Cannula–
D)Conjunctiva balloons out d/t fluid seepagefrom patent
Sclerotomy , requiring Conjunctival incision to locate
Sclerotomy site &suturing

36. Problem with Protruding Cannulas–Causeproblem in placing Sclerotomies in
Non- standard locations e.gcloser to verticalmeridian in casesaseyewith
severetrauma, extensive scleral wounds, Presenceof glaucoma drainage
valvesor filteringblebs
Suturing Of Sclerotomy –
Potential reasonsfor persistent leakageof Sclerotomymay
require suturings are
A)Thin Scleraasin High Myopia
B) Sclerotomy manipulated vigorously
C) AggressiveVitreous baseexcision
D) OpenConjunctiva asin Combined Vitrectomy & Buckling

37. • Complicationsof smallgaugevitrectomy –
Intraoperative Postoperative
Hypotony Hypotony
Intraocular Dislocation ofCannula Endophthalmitis
Instrument Breakage Retinal Detachment

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39. • ROMANO MR SCOTTI F VINCIGUERRA P
ANN ACAD MED
SINGAPORE.
•
• RIZZO S GENOVESI-EBERT F BELTING C
RETINA.