2. REGIONAL ANAESTHESIA IN OPTHALMIC SURGERY
MODERATOR :- Dr. RANI SUNDAR
PRESENTED BY :-
UMAKANTH
BIKASH

3. Introduction Anaesthetic requirements for ophthalmic surgery :
- Nature of the surgery
- Surgeon’s preference
- Patient’s preference
Local
Topical
Regional
General

4. Local anaesthesia for eyes
Non-akinetic and akinetic methods
Non –akinetic techniques
Topical ( drops & gel )
Subconjunctival
Deep fornix anaesthesia

5. Akinetic techniques Akinetic blocks : 1. Needle techniques
- Intraconal
- Extraconal
- Combined intraconal & extraconal
2. Cannula techniques
- Sub- tenon’s block
Ophthalmic surgeons prefer immobile eyes
Friedman et al - patients also prefer akinetic regional ophthalmic block.
Br J Ophthalmol 2004;88:333-5

6. Topical anaesthesia for eyes
Non-invasive
Minimal complications
Challenging operating conditions
– no akinesia
Popular for phacoemulsification cataract surgery
Careful patient selection
Co-operative
Must be able to lie supine & still
Sedation

7. Regional anaesthesia Advantages Disadvantages Day cases
Good akinesia & anaesthesia
Minimal effect on IOP
Minimal equipment required
Low failure rate & high safety profile
Disadvantages
Not suitable for all patients
Complications
Skill of anaesthetist
Unsuitable for certain types of surgery

8. Anatomy The orbit irregular four-sided pyramid
Apex - pointing posteromedially &
Base - facing anteriorly
Annulus of Zinn → fibrous ring arising from the superior orbital
fissure, forms the apex
The surface of cornea, conjunctiva & lids → forms the base
Globe movements are controlled by -
- Rectus muscles (inferior, lateral, medial &superior)
- Oblique muscles (superior & inferior)
Rectus muscles → origin - annulus of Zinn
insertion - anterior to the equator of the globe, Forms an incomplete cone

9. Orbit

10. Cone formed by rectus muscles

11. Nerve supply Within the muscle cone :- - Optic nerve (II)
- Oculomotor nerves (III)
- Abducent nerve (VI nerve),
- Nasociliary nerve (a branch of V nerve),
- Ciliary ganglion and vessels
ALL3 SO4 LR6
Trochlear nerve runs outside & above annulus→ superior oblique
(retained activity of this muscle is frequently observed ) .
Nasociliary nerve → Corneal & perilimbal conjunctival
Frontal & infraorbital nerves → remainder of the peripheral conjunctival

12. Cont.

13. Tenon’s space anatomy Tenon’s capsule → thin membrane enveloping the
globe & separating it from orbital fat
Inner surface separated from the outer surface of the sclera by a potential space the sub- tenon’s space
Sub- tenon’s space → lymphatic space
Follows the optic nerve & continues with subarachnoid space

14. Assessment and Preparation
British Ophthalmic Anesthesia Society :- fasting regimen
there is difference in clinical practice by different anaesthesist
Majority do not consider that it is necessary for the pt to be fasted prior to local anesthesia for eye surgery
( 65 % did not restrict any food or liquid intake )
Complication rates of starvation or aspiration in ophthalmic regional anesthesia are unknown
Pre-op investigations
Routine investigation of patients for catract surgery is not essential
Tests can be done to improve the general health of the patient if required.
Royal College of Anaesthetists and The Royal College of Ophthalmologists, 2001

15. Cont. Enquiry about bleeding disorders & related drugs
Konstantatos et al –
Patients on anticoagulants to continue their medication
Clotting results should be within therapeutic range.
Anaesth Intensive Care 2001;29:11-8
Recommendation for patients receiving antiplatelet agents
- Currently no recomendation
Katz J et al Study - Ophthalmology 2003; 110:
- Procedures under topical, subconjunctival, sub- Tenon’s
blocks are recommended
Konstantatos A et al - Anaesth Intensive Care 2001;29:11-8

16. Chassot et al :-
Extra occular & anterior chamber surgery can be conducted during dual antiplatelet theraphy
Posterior chamber procedures require cessation of clopidogrel ( but not asprine )
Only emergency surgery should be performed on full antiplatelet theraphy
The risk/benefit ratio of preoperative withdrawal of antiplatelet drugs in order to perform regional blocked is not justified
BJA 99 (3): (2007)

17. Risk factors that predispose globe penetration
Hamilton RC et al –
Risk factors that predispose globe penetration
- Presence of a long eye
- Staphyloma or enophthalmos
- Faulty technique
- Lack of appreciation of risk factors
- Uncooperative patient
- Use of unnecessarily long needles
OphthalmolClin North Am 1998;11:
Patients with axial myopia have greater risk of globe puncture
Risk rate is- 1 in 140 needle blocks with an axial length > 26 mm.
Duker et al: Ophthalmology 1991;98:
If axial length not known → power of patients spectacles
In highmyopia & in case of pre-existing scleral buckle a classical peribulbar block or a single medial peribulbar injection is advocated.
Johnson, International Practice of Anaesthesia &
Vohra SB ,Br J Anaesth 2000;85:242-5.

18. Cont. Intravenous line :-
Anaesthetic & surgical procedures are explained
All monitoring and anaesthetic equipments should be functional
Intravenous line :-
# Mathew et al - ? insertion of an IV line for topical
or sub- Tenon’s injection
J Cataract Refract Surg 2003;29:
# Anaesthetists and The Royal College of Ophthalmologists, 2001
- IV line must be inserted before embarking on
a needle block
# Kumar CM, Dodds et al -
- Presence of a secure IV line remains good clinical practice
Ophthalmic Anaesthesia. The Netherlands, 2002.

19. Types of regional anaesthesia
Akinetic Needle Technique
Peribulbar block (Pericone)
Retrobulbar block (Intracone, Atkinson’s)
Sub- Tenon’s block
(parabulbar block, pinpoint anaesthesia,
medial episcleral block)

20. Retrobulbar block – The Atkinson’s or classical retrobulbar block –
- Needle inserted through the skin, at the junction of
medial 2/3rd & lateral 1/3rd of the lower orbital margin
- 2 to 3 mL of local anaesthetic is injected deep into the
orbit behind the globe with the patient looking upwards
& inwards
- A separate 7th nerve block is required.

21. Cont. In modern retrobulbar block
- 25-G, 31-mm long needle is inserted through the
conjunctiva or skin in the inferotemporal quadrant as
far laterally as possible below the LR muscle.
- initial direction is tangential to the globe,
once past the equator ,needle goes upwards &
inwards to enter the space behind the globe
4 to 5 mL of local anaesthetic injected

22. Cont.

23. Cont. Insertion point & direction of needle for
extreme inferolateral intraconal injection
Final position of needle after intraconal
needle placement.

24. Peribulbar block : 2 injections
Inferotemporal injection
Injection is made outside the cone.
A 25-G, 31-mm long needle inserted through the conjunctiva as far laterally as possible in the inferotemporal quadrant.
Once the needle is under the globe, it is directed along the orbital floor.
5 mL of local anaesthetic agent is injected.
Many patients require a supplementary injection.

25. Cont.

26. Cont. Nasal injection A medial peribulbar block is performed to
supplement inferotemporal retrobulbar or peribulbar injection, particularly when akinesia is not adequate.
Rubin A. Eye blocks. In: Principles and Practice of Regional Anaesthesia :
Churhill Livingstone, 2003
25 or 27-G needle is inserted in the blind pit between the caruncle & medial canthus to a depth of 15 to 20 mm .
3 to 5 mL of local anaesthetic agent is injected

27. Cont.

28. Cont. Direction and placement of needle for
medial peribulbar injection

29. Needle Selection for Akinetic Block
Historically → 38 mm long needle
Chandra M Kumar et al –
Distance between inferior orbital rim & apex to 54 mm
Ciliary ganglion lie → 7 mm in front of the apex
( as per study in 120 cadaveric skull )
Hence ciliary ganglion is 35 mm from the inferior orbital rim
Patients with shallow orbit are at a ↑ risk with needles ≥ 35 mm
Vanden Berg et al –
Shorter (25 mm) needles are recommended
Some authors claim excellent results with 16-mm needles
Anaesthesia 2004;59:775-80

30. Bevel and tip of needle – controversy
Grizzard WS et al -
Sharp narrow-gauge needles (25 to 31 gauges) reduce
Discomfort on insertion at the expense of a reduced tactile feedback
Theoretically higher risk to recognise a globe perforation
Ophthalmology 1991;98:1011-6
Kimble JA et al –
Advantage of blunt needles
Blood vessels were pushed rather than traumatised
Tissue planes could be more accurately defined
Arch Ophthalmol 1987;105:749
Grizzard WS et al –
Blunt needles
More likely to cause greater damage when misplace

31. Complication of agent Systemic complication - Over dose
- Intravascular
- Allergic or vasovagal reaction.
- Into CSF within a cuff of dura around
the optic nerve
(confusion, convulsion, unconsiousness, respiratory & cardiac arrest)
- Over dose or intra vascular injection of adrenalin
- Allergic reaction to hyaluronidase

32. Complications of the techniques
Subconjuctival odema (chemosis )
Frequently follow large volume of peribulbar injection than retrobulbar injection
Resolves with use of pressure
No intra or postoperative problem
Bruising (ecchymosis )
Disfiguring
Conjuctival rather than skin injection to prevent bruising

33. Retrobulbar hemorrhage
Incidence = %
Predisposing factor : Elderly
Vascular or haematological disease
Pt on steroids, aspirin, NSAIDS, anticoagulant
Manifest by : Tight eyelids
Subconjuctival or periorbital hemorrhage &
Dramatic increase in IOP
Central retinal artery pulsation should be monitored
Impending retinal artery occlusion → Decompressive surgery or
Anterior chamber paracentesis
Postpone surgery
Cionni et al :-
If pressure reducing device decreases IOP, surgery can be
carried out opthalmology 1991: 98

34. Globe perforation Both in peribulbar & retrobulbar blocks
Incidence :- 1 in Gillow et al, Eye 1996;10:
1 in 12, Devis et al, J Catract Refract surg;1994:20
1 in 16, Manner et al, Eye 1996;10:
More in long & thin eye
Globes longer than 26mm are at risk
Pt who had or presenting for retinal detachment surgery and pt with myopia have long globes

35. Cont. Diagnosis by- Pain at time of injection Sudden loss of vision
Hypotonia
Poor red reflex or vitrous haemorage
When suspected or diagnosed →discuss with the surgeon
May be avoided by :
- Knowledge of orbital anatomy and length of globe
- Initial tangential niddle insertion
- Not going “up and in “ till niddle tip past the equator
- Aiming for inferior portion of superior orbital fissure
rather than orbital apex

36. Optic nerve atrophy- Amaurosis Occulo cardiac reflex
Direct injury to optic nerve or retinal artery
Injection into optic nerve sheath or hemorrhage in optic nerve sheath
Retrobulbar hemorrhage
May lead to partial or complete visual loss
Amaurosis
Mainly with retrobulbar block due to optic nerve block
Not with peribulbar block
Pt should be explained
Occulo cardiac reflex
Occasionally
Pt should be monitored

37. Penatration of optic nerve sheath
Injection into the dural cuff of optic nerve subarachnoid spread
of anaesthetic agent
Nicoll et al :-
In 6000 retrobulbar block , incidence is 1 in 375 with 1 in 700 life
threatening Anesthesia and analgesia;1987:66
Hamilton et al - incidence is 3 per 1000
Canadian journal of anaesthesia;1988: 35
All injection should be made with the globe in primary gaze position
Symptoms usually appear within 8 min
( immediately or upto 40 min after block)

38. - Most frequently affect the inferior rectus muscle
Sign & symptoms :- Drowsiness , vomiting
Contralateral blindness
Convulsion
Respiratory depression or arrest
Neurological deficit
Cardiac arrest
Myotoxicity
- Most frequently affect the inferior rectus muscle
- Usually recover but sometimes required corrective surgery
- Rainin etal
Highest concentration of local anesthetic should not be
used as they are found to be myotoxic
Archives of Opthalmology 1985;103
Direct injection into the muscle should be avoided

39. Sub Tenon’s Anaesthesia
Original idea of Turnbull (1884 )
Modified & popularised by Mein and Woodcock, Hansen, Stevens, Greenbaum & others
Also known as : Parabulbar block
Pinpoint anesthesia
Episcleral block

40. Anatomy of sub- tenon’s space

41. Sub- Tenon’s block Standard technique Obtaining surface anaesthesia
Access to the sub-Tenon’s space
Insertion of a cannula
Administration of local anaesthetic agent

42. Inferonasal quadrant is the most common site of access
(can be accessed from all 4 quadrants )
Stevens JD et al -
Inferonasal quadrant allows good fluid distribution superiorly
while avoiding area of surgery & damage to the vortex veins
Br J Ophthalmol 1992; 76: 670–674
With the patient - looking upwards & outwards
Conjunctiva & Tenon’s capsule are gripped with non-toothed forceps (Moorfield forceps) ,5 to 10 mm away from the limbus
A small incision is made with scissors ( Westcott scissors) to expose the sclera & the cannula is inserted following the globe

43. Cont.

44. Cannulae for Sub-Tenon’s Block
Metal or plastic
Commonly used cannula is → metal, 19-G, 2.54-cm long &
curved with a blunt end
Others Southampton cannula
Mid sub- Tenon cannula
Anterior cannula
Ultrashort cannula
Volume of LA varies from mL
( 3 to 5 mL is commonly used)
Smaller volumes →provide globe anesthesia
Larger volumes → if akinesia is desirable

45. One inch curved metal posterior sub-Tenon’s cannula

46. Plastic anterior sub-Tenon’s cannula.

47. Plastic mid-sub-Tenon’s cannula

48. Cont. Behndig A et al – Prolonged anesthesia & analgesia are obtained
by inserting a catheter in the sub-Tenon’s space.
J Cataract Refract Surg 1998;24:1307-9
Sub-Tenon’s block used primarily for cataract surgery
Also effective for →Viteroretinal surgery
Panretinal photocoagulation
Trabeculectomy
Strabismus surgery
Delivery of drugs
Sub-Tenon’s block favoured→ in patients on anticoagulants, aspirin & NSAIDs
Konstantatos A et al - Anaesth Intensive Care 2001;29:11-8

49. Passage of local anaesthetic agent during sub-Tenon’s injection
Ultrasound & MRI studies shows –
injected anesthetic agent opens the sub-Tenon’s
space giving a characteristic ‘T-sign’
Local anaesthetic agent diffuses into intraconal & extraconal areas resulting in anesthesia & akinesia of the globe & eyelids
Intense analgesia is produced by blockade of the short ciliary nerves as they pass through the Tenon capsule

50. characteristics ‘T-sign’.

51. Complications of Sub-Tenon’s Block
Minor complications → pain during injection, chemosis, conjunctival hemorrhage & leakage of local anaesthetic
Major complications → orbital & retrobulbar hemorrhage, rectus muscle paresis & trauma, globe perforation, central spread of local anesthetic, orbital cellulites etc
Most of these complications occurs following use of cm metal cannula.
Kumar CM et al - Eur J Anaesthesiol 2005;22:
Smaller or flexible cannulae appear to be safer but the incidence of minor complications increases.
Kumar CM & Dodds C et al - An Br J Anaesth 2001;87:631.

52. Pain during injection Multifactorial
Incidence with posterior metal cannula ≈ up to 44%
Pain scores on a VAS have been reported as high as 5
Stevens JD - Br J Ophthalmol 1992; 76: 670–674
Smaller cannulae appear to offer a marginal benefit
Kumar CM, & Dodds et al - Eye 2004; 18: 873–876
Guise PA et al -
Premedication or sedation during sub-Tenon’s injection does not add any benefit Anesthesiology 2003; 98: 964–968
Preoperative → explanation of the procedure, good surface anesthesia, gentle technique, slow injection of warm local anaesthetic agent & reassurance are considered good practice

53. Minor conjunctival hemorrhage
Chemosis-
Incidence ≈ 25 to 60% with a posterior cannula &
100% with shorter cannulae
Resolves with application of digital pressure
Minor conjunctival hemorrhage
Incidence ≈ 20 to 100% & depends on the cannula used
Loss of local anaesthetic volume during injection
Anaesthesia and akinesia
Akinesia is volume dependent
(large proportion develop akinesia with 4-5 ml of LA )
Superior oblique muscle & lid movements may remain active in a significant number of patients \

54. Pharmacological Considerations during Ophthalmic Regional Block
Local Anaesthetic Agent
All the modern LA are suitable & studies have shown little
difference in the quality of anesthesia, analgesia & akinesia
Adjuvant
Vasoconstrictors :-
- Increases the intensity and duration of block & minimize
bleeding from small vessels
pH Alteration :-
- Alkalization decreases onset time and prolong the
duration of effect after needle block
Zahl K et al - Anesthesiology 1990;72:230
- No such benefit is seen during sub-Tenon’s block.
Moharib et al - Reg Anesth Pain Med 2000;25:514-7

55. Hyaluronidase :-
Improves the effectiveness & quality of needle & sub- Tenon’s block
use remains controversial
The amount of hyaluronidase used - 5 to150 IU / mL
Orbital swelling - allergic actions or excessive doses & orbital pseudotumour have been reported
Others :-
Muscle relaxants & clonidine are known to increase the onset & potency of orbital block
use is neither routine nor recommended.

56. Sedation and Ophthalmic Regional Blocks
commonly used during topical anesthesia
patients, in whom explanation & reassurance have no benefit
Short acting BZP, opioids & small doses of IV anesthetic induction agents are used
The Royal College of Anaesthetists and The Royal College of Ophthalmologists, 2001
The routine use of sedation is discouraged
A means of providing supplemental O2 should be available
Sedation should only be used to allay anxiety & not to cover inadequate block

57. Intraocular Pressure (IOP) and Ophthalmic Regional Blocks
Changes in IOP after retrobulbar & peribulbar injections are controversial
IOP is generally reported to increase immediately after injection
Bowman R et al - Br J Ophthalmol 1996;80:394-7.
Palay DA et al - Ophthalmic Surg 1990;21:503-7.
Watkins R et al - Br J Ophthalmol 2001;85:796-8.
IOP is not seen to increase after sub-Tenon’s block
Ling R etal J Cataract Refract Surg 2002;28:113-7.
Vallance etal - J Cataract Refract Surg 2004;30:433-6.
Alwitry etal Eye 2001;15:733-5.

58. Retained Visual Sensations During Ophthalmic Regional Blocks
Many patients experience intraoperative visual sensations
This include light, colours, movements & instruments during
all forms of local ophthalmic anesthesia
During sub- Tenon’s block
(16%) found the experience to be unpleasant or frightening
Wickremasinghe et al - Eye 2003; 17: 501–-505
Patients receiving orbital blocks should receive preoperative
advice as this may alleviate an unpleasant experience

59. Intraoperative Care and Monitoring
Patient should be comfortable with soft padding over pressure areas
The Royal College of Anaesthetists and The Royal College of Ophthalmologists
All patients undergoing major eye surgery under local anesthesia should be monitored with
Spo2
ECG
NIBP
Maintenance of verbal contact

60. Choice of Technique
Preference for anaesthetic technique by surgeons & patients varies
Recent article by Friedman et al -
72% patients preferred block anesthesia to topical anesthesia
Br J Ophthalmol 2004;88:333-5.
Ruschen et al supports this view -
Patients have higher satisfaction scores with sub- Tenon’s block
over topical anesthesia alone.
Br J Ophthalmol 2005;89:291-3
The choice of technique depend on a balance between
- patient’s wishes
- operative needs of the surgeon
- skills of the anesthetist &
- place where such surgery is being performed

61. The Rules 2001 Guidelines (RCA & Coll. of Ophthalmologists)
Trained staff
Surgeons – topical /sub- conjunctival / sub- Tenon
( without anaesthetist )
Anaesthetist & iv access with retrobulbar & peribulbar blocks
Anaesthetist in charge when sedation is used

62. THANK YOU