Complications of Retrobulbar Blocks

Patient Safety Advisory Produced by ECRI Institute & ISMP under contract to the Patient Safety Authority Complications of Retrobulbar Blocks ver two dozen reports of retrobulbar hemor- Indications O rhages and at least three cases of respiratory If a retrobulbar block is considered, several factors arrest have been submitted to PA-PSRS since the will reduce the risk of complications. program’s inception in June 2004. These reports represent complications of the retrobulbar block, an Cooperation anesthetic technique used for intraocular surgery The patient must be able to follow instructions and that many practitioners are abandoning in place of cooperate with the surgical team.3,4 In order to follow topical anesthetics. directions, patients should not be hearing impaired or deaf, nor should there be a language barrier be- Declining Use of Retrobulbar Blocks tween the patient and surgical team.3,5,6 Hearing A recent survey indicates a move away from retro- aids, sign language interpreters, and/or foreign lan- bulbar blocks, while topical anesthesia is gaining guage interpreters may enhance cooperation. 1 greater acceptance. A 2003 survey of physician members of the American Society of Cataract and Positioning Refractive Surgery in the United States revealed this 3,5 2 The patient must be able to lie flat on his/her back. trend, presented in Table 1. Whereas in 1985, 76% As a result, diagnoses that prevent such a position of survey respondents used retrobulbar blocks with would be contraindications, such as severe back facial block, in 2003 only 17% of respondents used pain,4 postural problems,4 or chronic cardiac or res- this modality. The use of topical anesthesia has in- piratory problems.6 creased from 8% in 1995 to 61% in 2003. Interest- ingly, the use of topical anesthesia appears to be The ability to lie still is critical.3 Therefore, condi- associated with the volume of cataract procedures tions such as the following might make a patient an performed. Those respondent surgeons performing inappropriate candidate for the block: involuntary one to five procedures per month used topical anes- movements/tremors,3,6,7 uncontrolled convulsive thesia in 38% of their cases while those doing more disorder,5 unpredictable and uncontrolled cough,6 than 75 procedures monthly used it 73% of the time. excessive anxiety and claustrophobia.5

Each anesthesia modality, however, has unique benefits and risks. Table 23 displays this information Patients should be older than 15 years, because young patients are not as likely to remain still for various anesthesia techniques used in ocular 5,6 surgery. throughout the block and surgical procedure. Like- wise, oriented patients, without significant mental Anesthesia 1985 1995 2000 2001 2003 impairment produced by psychiatric disorders or dementia, are more likely to stay still and follow in- Retrobulbar block with- 11% structions.3,5 Moreover, oriented patients are more out facial block likely to be able to understand and tolerate the ef- Retrobulbar block with 76% 32% 14% 9% fects of a retrobulbar block on eye movement and facial block vision during and for some time after surgery.3 Peribulbar block 38% 17% Topical Anesthesia 8% 51% 61% This article is reprinted from the PA-PSRS Patient Safety Advisory, Vol. 4, − 81% 73% with intracameral No. 1—March 2007. The Advisory is a publication of the Pennsylvania lidocaine Patient Safety Authority, produced by ECRI Institute & ISMP under contract − 1-5 cataract proce- 38% to the Authority as part of the Pennsylvania Patient Safety Reporting System dures/month (PA-PSRS).

− more than 75 proce- 73% Copyright 2007 by the Patient Safety Authority. This publication may be dures/month reprinted and distributed without restriction, provided it is printed or distributed in its entirety and without alteration. Individual articles may be reprinted in their entirety and without alteration provided the source is clearly attributed. Table 1. Cataract Surgery Anesthesia Trends. Excerpted from Leaming DV. Practice styles and preferences of ASCRS To see other articles or issues of the Advisory, visit our Web site at members—2003 survey. J Cataract Refract Surg 2004;30: www.psa.state.pa.us. Click on “Advisories” in the left-hand menu bar. 892-900, with permission from Elsevier.

Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 4, No. 1 (March 2007)

Complications of Retrobulbar Blocks (Continued) Coagulation present.6,8 There must be enough room between This block is appropriate for patients with no signifi- the globe and the bony orbit to safely perform the cant bleeding or coagulation disorders.5 There is a block.7 Normal intraocular pressure and absence of difference of opinion concerning whether anticoagu- glaucoma are appropriate indications.6 The block lants, NSAIDS, aspirin, or clopidogrel bisulfate should not be completed if the globe is perforated.5,6 should be stopped prior to this block. One perspec- The patient must have no known allergy/cross sensi- tive is that patients receiving such medications are tivity to the local anesthetic to be used in the block.6 at greater risk of developing a retrobulbar hemorrhage.8 Another perspective is that it is acceptable Co-morbidities to perform a retrobulbar block if the patient’s INR Because of the potential for significant complica- does not exceed twice the normal values.9 tions, patients who receive retrobulbar blocks should not be blind in the non-operated eye.6 Patients are Globe less likely to sustain a retrobulbar hemorrhage if Anatomical abnormalities (e.g., a myopic axial they do not have diseases that make the vascula- length greater than 26 to 32mm) should not be ture more fragile, such as acquired arteriosclerotic

Anesthesia Benefits Risks General • Excellent anesthesia, analgesia, akinesia • Malignant hyperthermia • Duration of anesthesia can be varied to accommo- • Hemodynamic fluctuation date length of surgery • Postoperative nausea and vomiting • Allergic reactions • Increased risk of cardiac complications • Ocular complications: − pressure fluctuation − Valsava retinopathy − corneal abrasions − chemical injury • Requires more medication, equipment, personnel, therefore most costly form of anesthesia • Inefficiency: time required for induction, intubation, extubation

Regional: • Excellent anesthesia, analgesia, akinesia • Patient may move, therefore not as controlled as general retrobulbar, peribulbar, • Duration of effect lasts for most cataract surgeries anesthesia sub-Tenon’s • Cost of medications and equipment less than • Localized swelling, bruising, subconjuntival hemorrhage general anesthesia • Allergic reactions • Injections take little time therefore more time- and • Brainstem anesthesia cost-efficient than general anesthesia • Ocularcardiac reflex • Blind injection into orbit: − retrobulbar hemorrhage − globe perforation − optic nerve damage • Eye movement and vision affected for some time after surgery

− Peribulbar block • Decreased likelihood of optic nerve and global • Longer duration of onset perforation • Excellent akinesia and anesthesia

− Sub-Tenon’s injection with • Lower risk of local complications blunt cannulas

Topical • Most cost-and time-efficient • Rare local allergic reactions • Does not affect vision or motility therefore patients • Patients able to move eyes and other parts of the body may have improved and useful vision almost im- • Patient may perceive pain or pressure mediately after surgery • Patient may perceive visual phenomena • Minimal cosmetic changes • Avoids systemic risks of general anesthesia and risk of local trauma • Shortest duration of action

Table 2. Benefits and Risks of Ocular Surgery Anesthesia Types. Excerpted from Navaleza JS, Pendse SJ, Blecher MH. Choosing anesthesia for cataract surgery. Ophthalmol Clin N Am 2006 Jun;19(2):233-7, with permission from Elsevier.

Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 4, No. 1 (March 2007)

Complications of Retrobulbar Blocks (Continued) vascular disease, hypertension, coronary artery dis- • The abducens nerve (VI), which regulates ease, peripheral or cerebral vascular disease, or 10 motor control to lateral rectus muscle. diabetes mellitus. • The oculomotor nerve (III), which regu- Length of Surgical Procedure lates motor control to all other extraocular Retrobulbar blocks may be appropriate if the surgi- muscles. cal procedure is expected to last less than 90 minutes.5 • The trochlear nerve (IV), which regulates

motor control to superior oblique muscles. Anatomy To understand the technique of retrobulbar block All of these nerves except the trochlear pass and its complications, one must understand the through the retrobulbar muscle cone. As a result, eye’s basic anatomy and its relationship to sur- injecting a local anesthetic inside this cone provides rounding/supporting structures. anesthesia and akinesia of the globe, as well as the 1,7 1,7 extraocular muscles. The orbit is a pyramid-shaped cavity in the skull with a posterior apex and an anterior base. The orbit In addition to motor, sensory, and autonomic inner- is filled predominantly with adipose tissue, and the vation of the globe, there are many other structures globe (eyeball) is in the anterior portion of the cavity. within the retrobulbar muscle cone that can be at Four rectus muscles are attached around the equa- risk during retrobulbar injection including the optic tor of the globe. These muscles come together at the 7 nerve and many arteries and veins of the orbit, apex of the orbit, affixed by the tendon of Zinn. At including the optic artery.1,7 this point, the optic nerve enters the orbit. The retrobulbar cone is defined by these four rectus muscles. Technique

1,7 The goal of retrobulbar anesthesia is to direct the tip The following nerves innervate the globe. of the needle toward the orbital apex and into the retrobulbar muscle cone to diffuse the anesthetic • The ophthalmic nerve (V) (i.e., the first within this space. This blocks the ocular motor branch of the trigeminal nerve ), which con- nerves (III and VI) and sensory nerves (V), produc- trols sensory innervation of the globe. ing akinesia and anesthesia.1

Retrobulbar Block: Insert needle inferior to the maximum diameter of the globe and perpendicular to the plane of the face. Once past the axis of the globe, angle the needle medially and superiorly. Final needle position is within the muscle cone.

Figure 1. How the Retrobulbar Block is Performed

Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 4, No. 1 (March 2007)

Complications of Retrobulbar Blocks (Continued) To perform a retrobulbar block , a small amount of retrobulbar hemorrhage, globe penetration and local anesthetic is injected inside the retrobulbar perforation, optic nerve damage and atrophy, ex- muscle cone (see Figure 1). The conventional traocular muscle malfunction and injury, brain stem technique7 involves the following steps: anesthesia, globe ischemia, and complications of nerve VII.1,7,8 Table 38 displays these complications • Asking the patient to gaze in its primary with information concerning mechanism of injury, position or a “downward and outward” risk factors, incidence, prevention, and treatment. position.1 Two types of complications are evident in the PA-PSRS data: (1) central nervous system spread • Introducing the needle through the skin of anesthesia and (2) retrobulbar hemorrhages. below the inferior lid at a point between the

lateral one-third and medial two-thirds of the Central Nervous System Spread of Anesthesia inferior orbital edge. Unintentional intra-arterial injection of the anesthetic • agent during retrobulbar block may result in reverse Directing the needle to the apex of the orbit flow of the agent from the ophthalmic artery to the in a medial and cephalad direction cerebral or internal carotid artery. Seizures can result from injection of as little as 4cc.7 Rapid recovery • Advancing the needle to a depth of occurs with symptomatic treatment. 25 to 30mm The anesthetic can also be inadvertently injected • Injecting 2 to 5cc of local anesthetic under the dura mater sheath of the optic nerve or directly through the optic foramen, resulting in su- Performing a facial block to prevent blinking. The tech- barachnoid spread of the local anesthetic. The local nique most commonly used is the van Lindt block,7 anesthesia spreads directly to the brain from the orbit causing partial or complete brain stem anesthe- involving infiltration of local anesthesia in the areas of 9 the terminal branches of the facial nerve (VII).10 sia. Symptoms include cranial nerve palsy or bilat- eral block, sympathetic activation, restlessness, con- Previously, Atkinson’s “up and in” gaze was used for fusion, total spinal anesthesia with tetraparesis, arte- this block, but it is no longer advised because Liu et rial hypotension, bradycardia, and respiratory arrest. al. and Unsold et al. determined that this globe posi- Symptoms begin within about two minutes after injection and peak within 20 minutes. Recovery occurs tion increased the risk of optic nerve injury. Because 9 the optic nerve passes near the path of the needle, in two to three hours. Symptomatic treatment may include oxygen, vasopressors, tracheal intubation, it can be stretched or injured by the needle, rather 7 than pushed aside as intended. This gaze position and ventilation. also places the needle near other structures such as the ophthalmic artery, superior orbital vein, and the There are at least three cases of respiratory arrest posterior pole of the globe.1,7 Unsold et al. recom- following retrobulbar blocks that have been reported mends that the patient gaze with the globe in its pri- to PA-PSRS. mary position or in a down and outward position.1 These positions place the optic nerve, blood ves- Retrobulbar Hemorrhage sels, and the inferior oblique muscle outside the Over two dozen reports of retrobulbar hemorrhage needle’s path. have been reported to PA-PSRS. The overall incidence of this complication varies from between 1,3,8 Retrobulbar anesthesia is a blind technique. As a 0.1% to 3%. Hemorrhage is caused by needle result, damage can result to the globe, orbital tis- penetration of either the venous or arterial vessels in 7,8 sues, and neurovascular structures.1 Near the apex, the orbit. many structures are packed in a small area and fixed by the tendon of Zinn; therefore, the structures Venous cannot move away from or be pushed aside by the Most retrobulbar hemorrhages are venous, and needle.7 bleeding is slow.1 Venous hemorrhages do not ordi- narily threaten vision, the consequences are less Complications severe than arterial hemorrages,7 and they require The literature describes several complications of no intervention other than postponing the surgery for retrobulbar blocks, including chemosis, bruising, which the block was administered.1,7

Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 4, No. 1 (March 2007)

Complications of Retrobulbar Blocks (Continued) Arterial Risk Reduction Strategies Arterial hemorrhages, however, can be more seri- Addressing the following issues can help achieve ous. An arterial hemorrhage is evident within a few safe and successful retrobulbar blocks (and any aki- 1,8 minutes; symptoms include proptosis and tight eye- netic block of the eye): lids, ecchymosis, chemosis (i.e., conjunctival blood vessel engorgement), blood staining of periorbital • Education and competencies tissues, lid swelling, and a dramatic increase in in- − Ensuring knowledge of anatomy and the traocular pressure.1,8 Late optic atrophy may also relationship between the globe, orbit, result if the microvasculature of the optic nerve be- and other ocular-related structures. comes occluded. A compressive retrobulbar hema- 2 − Having training and checking competen- toma may threaten retinal perfusion by causing 12 central retinal artery occlusion.1 cies in performing the technique.

• The cause of retrobulbar hemorrhage is misplace- Patient condition ment of the needle during this “blind” procedure. − Evaluating the globe for pathological The risk of retrobulbar hemorrhage depends on the abnormalities (e.g., abnormal axial experience of the person performing the block; for length of the globe). example, the complication is more likely if the per- − In severely hypertensive patients, con- son performing the retrobulbar block has limited sider postponing surgery until blood 7,9 experience. pressure is under greater control.9

Patient-related risk factors include elderly patients • Technique receiving anticoagulants, NSAIDS, aspirin or ster- − Using techniques based upon anatomi- oids.8 However, it is considered acceptable to per- cal knowledge and existing ophthalmic form this block if the INR does not exceed twice the pathology, including the following: normal value.9 Patients with acquired vascular dis- 1 ease are at risk, as are those with diseases pro- ° moting arterial fragility such as diabetes or Using a small gauge needle (25 atheroma.7 Hypertensive patients may also be at gauge) no longer than 31 mm in 9 risk for this complication. Those at higher risk in- length. (This reduces the risk of clude patients with a history of previous eye surgery both retrobulbar hemorrhage and and those with pathological abnormalities of the brain stem anesthesia.) globe, such as extreme myopia, myopic staphy- ° Inserting the needle when the eye is loma, coloboma, or scleral buckle.1,8 in primary gaze. ° Placing the needle tangential to Timely, effective treatment for retrobulbar hemor- the globe. 1 rhage can prevent permanent impairment of vision. ° Avoiding placement of the needle Most retrobulbar hemorrhages can be successfully 8 into the vascular quadrant or mus- treated conservatively. Immediate oculocompres- cle belly by smoothly and gently sion helps limit the extent and severity of the hem- 8 inserting the needle into a relatively orrhage. The goal of treatment is to reduce com- avascular area. partment pressure, thereby reducing intraocular ° Aspirating before injecting the local pressure, which in turn reduces negative outcomes 8 anesthetic agent, to check for blood. on retinal circulation. The ophthalmologist will evaluate the extent of the hemorrhage and deter- ° Consider repositioning the needle if mine whether further interventions are necessary.1,8 resistance occurs during injection. Interventions may include measuring intraocular pressure and checking retinal circulation.8 Intraocu- • Anesthesia/sedation 8 lar pressure can be lowered with acetazolamide. ⎯ Considering other anesthesia modalities Immediate lateral canthotomy/cantholysis may be that may have fewer complications.1 required to relieve orbital pressure caused by the 1 retrobulbar hemorrhage. Emergency orbital de- Finger Index compression surgery may be necessary if the optic The Finger Index (FI) is a grading system (0 to 3; 1,7 nerve is compromised. see below) used in the Helsinki University Eye

Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 4, No. 1 (March 2007)

Complications of Retrobulbar Blocks (Continued) Hospital in Finland6 that can determine the accessi- FI=2: Finger easily fits between the orbit and globe. bility of the retrobulbar/peribulbar space in advance (Patients are suitable for retrobulbar/ of needle injection. The tighter the globe is situated peribulbar anesthesia; the block may be ad- near the wall of the orbit, the more difficult the nee- ministered by an appropriately educated and dle insertion. One finger palpates the space be- supervised physician in training.) tween the orbit and globe. FI=3: Finger reaches the level beyond the equator FI=0: Globe lies tightly on the rim of the orbit and of the globe. (Patients are suitable for retrobul- cannot be lifted at all by the fingertip. bar/peribulbar anesthesia; the block may be (Retrobulbar/peribulbar blocks are contraindi- administered by an appropriately educated cated in such patients.) and supervised physician in training.)

FI=1: Only the tip of the finger fits between the globe Further study is needed to determine whether this and orbit. (Patients require an expert medical grading system can be scientifically validated. How- staff member to perform the block.) ever, it may provide a supplemental screening

Complications Mechanism Risk Factors Incidence Prevention Treatment Chemosis Anterior spread of Injection with smaller Not known Avoid anterior injection Usually resolves on oculo- local anesthetic agent needles compression Bruising Damage to superficial Elderly receiving steroids, 1-2.75% Avoid injection through Usually resolves and spread blood vessels during NSAID, aspirin visible blood vessels can be limited by oculocom- injection pression Retrobulbar hemor- Damage to arterial or Elderly receiving steroids, 0.1-3% Limit insertion of needle Immediate oculocompression, rhage venous blood vessels NSAID, aspirin to less than 31mm in the ophthalmologic opinion and behind the globe relatively avascular area decompression surgery Globe penetration Penetration of globe Myopic eye, uncooperative 0-1% Use of technique based Immediate senior ophthalmo- and perforation (wound of entry) and patient, inexperienced on sound anatomical logic opinion perforation (wounds of user, poor technique, principles entry and exit) previous surgery Optic nerve damage Direct damage to Rare Surgical decompression may nerve or compression be required of the nerve secondary to hemorrhage or vascular occlusion Optic nerve atrophy Direct damage to Rare Careful needle placement Delayed complication nerve, central retinal artery or secondary to hemorrhage Damage to the Direct trauma to the Insertion of needle at the Not known Careful needle placement motor nerve of the nerve junction of medial 2/3 and avoiding the nerve inferior rectus and lateral 1/3 of inferior orbital inferior oblique margin muscles Inadvertent su- Subject to debate but Placement of long needle 0.3-0.8% Avoid using long needle Extensive cardiorespiratory barachnoid anesthe- spread through optic into the apex support sia (brain stem nerve sheath or anesthesia through the orbital foramina Globe ischemia Interruption of blood Prolonged oculocompres- Rare Use pressure limiting flow sion oculocompression device Prolonged extraocu- Prolonged exposure of May be associated with Not known Proper placement of lar muscle malfunc- fine muscle fibers, non-use of hyaluronidase needle tion injection of local anesthetic agent into the muscle Complications of 7th Direct damage to the Rare nerve block nerve or neurogenic in origin

Table 3. Complications of Akinetic Needle Block, Mechanism, Risk Factors, Incidence, and Their Prevention and Treatment. Source: Kumar CM, Dowd TC. Complications of ophthalmic regional blocks: their treatment and prevention. Ophthal- mologica 2006;220:73-82. Reprinted with permission of S. Karger AG, Basel, Publisher.

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Complications of Retrobulbar Blocks (Continued) method in addition to other risk reduction strategies A review of complications of ophthalmic regional to determine: (1) patients’ appropriateness of such blocks includes: procedures and (2) the level of expertise required for the performance of the procedure. • Kumar CM, Dowd TC. Complications of ophthalmic regional blocks: their treatment Conclusion and prevention. Ophthalmologica 2006;220 The key to selecting the most appropriate anesthe- (2):73-82. sia technique is for the surgeon, anesthesiologist, and the patient to work together during the anesthe- Notes sia selection process, prior to surgery, and during 1. Cyriac IC, Pineda R. Postoperative complications of periocular anesthesia instillation.5 Describing to the patient anesthesia. Int Ophthalmol Clin 2000 Winter;40(1):85-91. what he/she will experience before, during, and after 2. Leaming DV. Practice styles and preferences of ASCRS members—2003 survey. J Cataract Refract Surg 2004 Apr;30(4): surgery will reduce fear and anxiety and promote 892-900. patient cooperation. While ophthalmologists rou- 3. Navaleza JS, Pendse SJ, Blecher MH. Choosing anesthesia tinely perform retrobulbar blocks, anesthesia staff for cataract surgery. Ophthalmol Clin N Am 2006 Jun;19 can perform such blocks, as well as provide support (2):233-7. 4. American College of Eye Surgeons. Alternate guidelines for to the patient by adjusting IV sedation to reduce 3 cataract surgery [guideline]. 1996 Feb. discomfort. 5. Retrobulbar blocks. Anesthesiology Info [online]. 1999 Jan 18 [cited 2006 Aug 25]. Available from Internet: http:// Resources anesthesiologyinfo.com/articles/12092002.php. 6. Kallio H, Rosenberg PH. Advances in ophthalmic regional Resources concerning anesthesia alternatives for anesthesia. Best Pract Res Clin Anaesthesiol 2005 Jun;19(2): cataract surgery include: 215-227. 7. Ripart J, Nouvellon E, Chaumeron A. Regional anesthesia for • eye surgery. Reg Anesth Pain Med 2005 Jan-Feb;30(1):72-82. Schein OD, Friedman DS, Fleisher LA, et al. 8. Kumar CM, Dowd TC. Complications of ophthalmic regional Anesthesia management during cataract blocks: their treatment and prevention. Ophthalmologica surgery [evident report/technology assess- 2006;220(2):73-82. ment]. No. 16 (Prepared by the Johns Hop- 9. Faccenda KA, Finucane BT. Complications of regional anaes- thesia: incidence and prevention. Drug Saf 2001;24(6):413-42. kins University Evidence-based Practice 10. Edge KR, Nicoll JM. Retrobulbar hemorrhage after 12,500 Center under Contract No. 290-097-0006.) retrobulbar blocks. Anesth Analg 1993 May;76(5):1019-22. AHRQ Publication No. 01-E017. Rockville, 11. Coleman R. Retrobulbar block for cataract surgery. AANA J MD: Agency for Healthcare Research and 1980 Oct;48(5):429-36. 12. Coalition for Cataract Surgery: American College of Eye Sur- Quality. December 2001 geons, Ophthalmic Anesthesia Society, Outpatient Ophthalmic Surgery Society, Society for Geriatric Ophthalmology. Alternate • Navaleza JS, Pendse SJ, Belcher MH. guidelines for cataract surgery [guidelines]. 1993. Choosing anesthesia for cataract surgery. Ophthalmol Clin N Am 2006 Jun;19(2):233-7.

• Friedman DS, Bass EB, Lubomski LH, et al. Synthesis of literature on the effectiveness of regional anesthesia for cataract surgery. Ophthalmology 2001 Mar;108(3):519-529.

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The Patient Safety Authority is an independent state agency created by Act 13 of 2002, the Medical Care Availability and Reduction of Error (“Mcare”) Act. Consistent with Act 13, ECRI Institute, as contractor for the PA-PSRS program, is issuing this newsletter to advise medical facilities of immediate changes that can be instituted to reduce Serious Events and Incidents. For more information about the PA-PSRS program or the Patient Safety Authority, see the Authority’s Web site at www.psa.state.pa.us.

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