Ocular perforation following retrobulbar anesthesia for retinal detachment surgery

A Review of Novel Anesthetic Technique for Vitreoretinal Surgery

BACKGROUND AND OBJECTIVE

Currently, there is no standardized formulation of intravenous anesthetic that exists for vitreoretinal surgery. We describe a novel anesthetic protocol for vitreoretinal surgery that is safe and effective for patients and surgeons alike.

STUDY DESIGN

Review the current challenges to vitreoretinal anesthetic technique and descriptive overview outlining the proposed anesthetic protocol and associated experience with technique.

RESULTS

The proposed anesthetic technique utilizes a sub-tenon peribulbar block with a continuous propofol infusion. A low dosage continuous propofol infusion provides patients with profound anxiolysis and relaxation while maintaining wakefulness. Fentanyl can be additionally titrated for patients that report symptoms of pain or increased respiratory rate.

CONCLUSION

A low dose propofol infusion in combination with sub-tenon peribulbar block and judicious use of fentanyl provide an ideal operative condition for ambulatory vitreoretinal surgery. [Ophthalmic Surg Lasers Imaging Retina 2023;54:xx-xx.].

Patient Satisfaction With Oral vs Intravenous Sedation for Vitrectomy Surgery: A Randomized, Noninferiority Clinical Trial

Purpose

This work aims to determine whether patient satisfaction with oral sedation is noninferior to intravenous (IV) sedation in vitrectomy surgery.

Methods

This prospective, randomized, double-masked, noninferiority clinical trial measured patient satisfaction in 84 participants receiving oral or IV sedation during vitrectomy surgery under monitored anesthesia care. Patients were excluded if they were unable to receive benzodiazepines.

Results

The primary outcome was patient satisfaction. Secondary outcomes included surgeon and anesthesia provider satisfaction, need for supplemental anesthesia, and surgical complications. Among the 84 patients (46 [54.8%] men; mean [SD] age, 57.0 [12.7 years]), mean patient satisfaction scores were 5.22 ± 0.81 (range, 3.08-6; scale 1-6) with oral and 5.25 ± 0.63 (range, 3.83-6; scale 1-6) with IV sedation. With an a priori noninferiority margin of 0.5 and a difference in mean scores between the groups of 0.03 (1-tailed 95% CI, infinity to 0.29), our results demonstrated the noninferiority of oral sedation (P = .002). There were no significant differences in surgeon or anesthesia satisfaction or major intraoperative complications. Five patients receiving oral (11.9%) and 3 receiving IV (7.1%) sedation required supplemental IV sedation (difference, 4.8%; P = .46).

Conclusions

Patient satisfaction for oral sedation was noninferior to IV sedation for vitrectomy surgery.

Patient and surgeon comfort in vitreoretinal surgery performed with Sub-Tenon's Anaesthesia

Background. Since Stevens first introduced Sub-Tenon's anaesthesia into cataract surgery it has shown itself to be a safe, simple, and efficient technique. The advantages of this type of block are comparable to those of sharp needle anaesthesia and complications are minimal. Several studies have found that the anaesthesia provided by Sub-Tenon's capsule injection is as good as or better for cataract surgery than that achieved by retrobulbar injection, but the efficacy of Sub-Tenon's block in vitreoretinal surgery is less well established. Methods. We performed 50 vitreoretinal procedures; 50 eyes received a Sub-Tenon's injection of a 5 ml mixture (50:50) of lidocaine and ropivacaine, plus 15 IU mL-1 of Hyaluronidase. Results. In 45 cases, only one injection was needed to achieve sufficient anaesthesia and akinesia; in 5 cases a second injection was performed five minutes after the first. Mean surgical time was 45.7 minutes. After surgery, each patient was asked to indicate his value on the VAS pain scale. Mean VAS degree was 2.4. In 7 cases, VAS was > 3 and the pain was successfully managed with the administration of paracetamol in the postoperative period. No light perception was detected at the end of surgery in 33 patients. All cases with 2 injections had no light perception at the end of surgery. Anaesthesia lasted throughout the surgery in all cases. The surgeon performed all surgery comfortably and with no difficulty. Conclusions. According to our experience and to a growing body of evidence, Sub-Tenon's anaesthesia appears to be a safe, simple, versatile, and effective technique and should be considered as a real alternative method of anaesthesia in vitreoretinal surgery.

Inadvertent globe penetration during retrobulbar anesthesia: A case report

BACKGROUND

To report the possible reasons for needle perforation and complications related to perforation, as well as the clinical management of subretinal hemorrhage (SRH) during retrobulbar injection.

CASE SUMMARY

A 65-year-old female was scheduled to undergo pars plana vitrectomy (PPV) in her left eye for rhegmatogenous retinal detachment (RRD). During retrobulbar anesthesia, needle perforation of the globe occurred. Massive SRH in the inferotemporal quadrant together with vitreous hemorrhage were observed. The patient underwent PPV combined with retinotomy for removal of the massive SRH. After earlier surgical intervention, successful reattachment of the retina was achieved.

CONCLUSION

Inadvertent globe penetration during retrobulbar anesthesia is associated with a poor prognosis and may result in blindness. Timely detection and earlier intervention may be beneficial.

Ocular complications of perioperative anesthesia: a review

Ocular complications associated with anesthesia in ocular and non-ocular surgeries are rare adverse events which may present with clinical presentations vacillating between easily treatable corneal abrasions to more serious complication such as irreversible bilateral vision loss. In this review, we outline the different techniques of anesthetic delivery in ocular surgeries and highlight the incidence and etiologies of associated injuries. The changes in vision in non-ocular surgeries are mistaken for residual sedation or anesthetics, therefore require high clinical suspicion on part of the treating ophthalmologists, to ensure early diagnosis, adequate and swift management especially in surgeries such as cardiac, spine, head and neck, and some orthopedic procedures, that have a comparatively higher incidence of ocular complications. In this article, we review the literature for reports on the clinical incidence of different ocular complications associated with anesthesia in non-ocular surgeries and outline the current understanding of pathophysiological processes associated with these adverse events.

Real-time ultrasound-guided retrobulbar block vs blind technique for cataract surgery (pilot study)

Background

Retrobulbar regional eye block aims to ensure eye globe akinesia and anesthesia during ophthalmic surgery, and despite the rarity of occurrence of complications due to the blind needle passage while performing either peribulbar or retrobulbar block, some of them are serious and may be life threatening.

Aim

The aim of this study was to estimate the accuracy and safety of real-time ultrasound-guided retrobulbar regional anesthesia in comparison with the blind technique for cataract surgery.

Design

This was a prospective randomized controlled trial.

Methodology

A total of 30 patients who met the inclusion criteria were registered in our research and were divided into two groups: 15 patients received real-time ultrasound-guided retrobulbar block compared to 15 patients who received the block using the blind technique.

Results

One patient out of the 30 was excluded from the analysis, and no statistically significant differences were observed between the two groups regarding the onset of akinesia, numeric pain rating scores, rate of complications, and degree of patient and physician satisfaction.

Conclusion

There were no statistically significant difference between real-time ultrasound-guided and blind retrobulbar regional eye blocks concerning the onset of action, total volume of injected local anesthetic solution, supplemental injection required, pain scores, and degree of patient satisfaction.

Displacement of crystalline lens into the sub-conjunctival space following periocular anesthesia

A 65-year-old female presented with loss of vision and a mass in her right eye after periocular anaesthesia for cataract surgery in a camp. She was found to have a nasal subconjunctival mass, which was confirmed to contain the crystalline lens after surgical exploration, along with a superior perilimbal suspected scleral rupture. There was accompanying vitreous haemorrhage, retinal detachment and subretinal haemorrhage that was managed by pars plana vitrectomy. Post operatively, she achieved a best corrected visual acuity of 20/80 that was maintained till 6 months follow up. Globe rupture and subconjunctival lens extrusion in the setting of inadvertent globe penetration during periocular anesthesia is a rare complication. In the absence of medical records pertaining to the primary event, this clinical presentation posed a diagnostic challenge. Timely and appropriate management led to an acceptable visual and anatomical outcome in this unfortunate and devastating scenario.

Evaluation of ocular perforation during retrobulbar block using high-resolution spectral domain–optical coherence tomography and optical coherence tomography angiography

Introduction:

This article reports a case of ocular perforation during a retrobulbar block in a patient who underwent scleral buckle for retinal detachment.

Methods:

Sterile air was immediately injected into the vitreous cavity to restore intraocular pressure and the scleral buckle operation was quickly finished. One week later, a laser retinopexy was performed on the two retinal holes that were outside the foveal area. After 6 months, spectral domain–optical coherence tomography and optical coherence tomography angiography were performed on the perforated wall centered on the exit hole area.

Results:

The visual acuity was maintained 20/20 and the retina was totally attached. Spectral domain–optical coherence tomography showed a localized interruption of inner retina, retinal pigment epithelium, and choroid, with a higher posterior reflectivity in correspondence with the sclera. Optical coherence tomography angiography was able to detect atrophic alterations in the choroidal slab with a good visualization of large and rarefied choroidal vessels due to lack of retinal pigment epithelium and choriocapillaris.

Conclusion:

When ocular perforation by a needle is outside the foveal area and when there is an early awareness of the perforation, the complications may be avoided, and we could observe a good final visual acuity result. Furthermore, using spectral domain–optical coherence tomography and optical coherence tomography angiography, we could observe the perforated eyeball wall and study the effects of a 25-gauge needle perforation in the retinal and choroidal blood stream.

Bilateral subcutaneous emphysema from pressurized infusion during pars plana vitrectomy: a case report

OBJECTIVES

To report a case of extensive subcutaneous emphysema introduced during vitrectomy while using an advanced feedback-controlled pressurized infusion system.

METHODS

Clinical case report of a 56-year-old woman undergoing pars plana vitrectomy for rhegmatogenous retinal detachment of the left eye. The clinical and radiologic findings of the patient's eyes were documented. The mechanisms of feedback-controlled pressurized infusion devices were reviewed to explain the adverse events. A search of PubMed was conducted to look for any similar cases and/or discussion.

RESULTS

In this surgical case, vitrectomy was completed with air-fluid exchange and a formed anterior chamber was observed with an estimated pressure of high teens to low 20s by the surgeon. After the undraping, the patient was noted to have severe facial crepitus extending to the clavicles. Immediate chest X-ray was done, followed by computed tomography, confirming orbital and subcutaneous emphysema, as well as the presence of perfluoro-N-octane in the left orbit.

CONCLUSION

Integrated pressurized infusion devices using feedback sensors allow for a sophisticated method of maintaining intraocular pressure and globe formation. However, inadvertent or occult globe rupture may lead to disruption of feedback control and subsequent high rates of infusion. As the infused substances exit the site of rupture, they can lead to extensive extraocular gas or fluid accumulation, and we report a case of severe bilateral subcutaneous emphysema as a result.

A review of directions of gaze during intraocular anesthetic blocks

Safety of orbital blocks depends on operator and patient factors. Among the patient factors, the direction of gaze is important. Certain ocular structures move when the gaze is shifted. These may veer into the path of the needle, setting the stage for injury. The optic nerve with its accompanying artery swerves medially during abduction, direct up gaze, and superolateral and inferolateral gazes. These gazes are therefore risky for medial compartment blocks. In a superomedial gaze, the optic nerve shifts down and out and is likely to be injured during inferolateral needle blocks. Primary gaze is considered to be the safest for akinetic sharp needle blocks. "Tethering tests" involving extremes of gazes are dangerous. The superomedial, superior, superolateral, and inferomedial routes are perilous in all gazes. The superolateral gaze during classic Steven's sub-Tenon's block brings the optic nerve forward, rendering it vulnerable. Complications can be reduced by avoiding deep blind dissection and posterior injections.

Endophthalmitis due to inadvertent globe penetration during retrobulbar injection of saline solution for laser in situ keratomileusis

A 31-year-old woman presented with visual acuity of counting fingers and presumed bacterial endophthalmitis in the left eye 10 days after refractive surgery. During the procedure, a retrobulbar injection of balanced salt solution had been performed to assist with globe suction by the microkeratome. A perforation site was identified in the inferonasal retina. Following intravitreal antibiotic injection and surgical intervention, the visual acuity returned to 20/20. Retrobulbar injection to facilitate laser in situ keratomileusis carries risks. Careful monitoring for signs of infection is recommended if globe perforation is recognized.

Real-time visualization of ultrasound-guided retrobulbar blockade: an imaging study

BACKGROUND

Retrobulbar anaesthesia allows eye surgery in awake patients. Severe complications of the blind techniques are reported. Ultrasound-guided needle introduction and direct visualization of the spread of local anaesthetic may improve quality and safety of retrobulbar anaesthesia. Therefore, we developed a new ultrasound-guided technique using human cadavers.

METHODS

In total, 20 blocks on both sides in 10 embalmed human cadavers were performed. Using a small curved array transducer and a long-axis approach, a 22 G short bevel needle was introduced under ultrasound guidance lateral and caudal of the eyeball until the needle tip was seen 2 mm away from the optic nerve. At this point, 2 ml of contrast dye as a substitute for local anaesthetic was injected. Immediately after the injection, the spread of the contrast dye was documented by means of CT scans performed in each cadaver.

RESULTS

The CT scans showed the distribution of the contrast dye in the muscle cone and behind the posterior sclera in all but one case. No contrast dye was found inside the optic nerve or inside the eyeball. In one case, there could be an additional trace of contrast dye behind the orbita.

CONCLUSIONS

Our new ultrasound-guided technique has the potential to improve safety and efficacy of the procedure by direct visualization of the needle placement and the distribution of the injected fluid. Furthermore, the precise injection near the optic nerve could lead to a reduction of the amount of the local anaesthetic needed with fewer related complications.

[Retinal detachment caused by ocular perforation during periocular anesthesia: three case reports]

INTRODUCTION

Local anesthesia for eye surgery was first described in 1884; later Knapp popularized retrobulbar anesthesia. To reduce risks, peribulbar anesthesia appeared in the 1970s. Still used today, periocular anesthesia is not without complications, in particular the risk of ocular perforation.

PATIENTS AND METHODS

Three patients were referred to our department for diagnosis and treatment of an intravitreous hemorrhage following cataract surgery. We report the clinical features, treatment, and visual outcome for these three patients.

RESULTS

The most common presentation was vitreous hemorrhage: the three eyes were found to have associated retinal detachment on initial assessment. One patient presented severe vitreoretinal proliferation with two postoperative recurrences; the globe was finally enucleated. The two other patients presented attached retina after surgery but had achieved very poor visual recovery.

CONCLUSION

Inadvertent globe perforation during local ocular anesthesia is rare. Careful attention to risk factors, early recognition, and prompt referral for management are recommended to improve the visual prognosis. Surgical management must be adapted to the severity of the perforation (vitreous hemorrhage, retinal detachment, vitreoretinal proliferation). The problems treating these patients with severe, often recurrent, retinal detachment, with poor visual prognosis, in a tricky forensic context should be emphasized.

Subtenon lidocaine vs topical proparacaine in adult strabismus surgery

Intraoperative subtenon 2% lidocaine and topical 0.5% proparacaine in patients undergoing strabismus surgery were compared. No additional systemic analgesics and sedatives were used. Mean and total pain scores intraoperatively and postoperatively were not different. Each anesthetic agent provides good intraoperative anesthesia and postoperative analgesia. Topical 0.5% proparacaine may be preferred because of its easy administration and fewer side effects, lack of hospital admission, and immediate and predictable alignment of the eyes.

Serious complications of local anaesthesia for cataract surgery: a 1 year national survey in the United Kingdom

BACKGROUND

The techniques of sub-Tenon's, topical and topical-intracameral local anaesthesia (LA) have become common in routine practice.

AIMS

This study aimed (i) to estimate the frequency of various LA techniques used in cataract surgery, (ii) to estimate the incidence of severe adverse events associated with each LA technique, and (iii) to document these adverse events.

METHODS

This was a prospective, 13 month observational study of routine practice in the UK in 2002-2003. The British Ophthalmological Surveillance Unit sent a monthly mailing to UK ophthalmologists, asking for reports of "potentially sight-threatening or life-threatening complications of LA for cataract surgery". Current LA practice was assessed by questionnaire.

RESULTS

Cataract surgery comprised 4.1% general anaesthesia, 92.1% LA without sedation and 3.9% LA with sedation. Of the estimated 375 000 LAs 30.6% were peribulbar, 3.5% retrobulbar, 42.6% sub-Tenon's, 1.7% sub-conjunctival, 9.9% topical and 11.0% topical-intracameral LA. "Potentially sight-threatening complications" were mostly associated with retrobulbar and peribulbar techniques and "potentially life-threatening" complications with all techniques except topical/intracameral LA. Eight neurological complications consistent with brainstem anaesthesia were reported: 7 with peribulbar or retrobulbar LA. Poisson regression analysis strongly indicated that rates vary with technique (p<0.001 for "potentially sight-threatening" complications, p = 0.03 for "neurological" complications). Because of likely under-reporting, further complications probably occurred during the survey period.

CONCLUSIONS

This large survey found a lower rate of reported serious complications with sub-Tenon's, topical and topical-intracameral LA compared with retrobulbar and peribulbar techniques. These "newer" methods may be preferable for routine cataract surgery.

Combined propofol sedation with sub-Tenon's lidocaine/mercaine infusion for strabismus surgery in adults

AIMS

To evaluate the safety and efficacy of propofol sedation combined with sub-Tenon's anaesthesia for strabismus surgery in adults.

METHODS

Thirty-two consecutive patients aged 31-85 years underwent strabismus surgery under general (n=16) or local (n=16) anaesthesia. In the local anaesthesia (study) group, sedation was induced with a loading dose of midazolam, fentanyl, and propofol, followed by continuous infusion of propofol, 3-6 mg/k/h to deep sedation. A nasal tube was inserted to prevent airway obstruction. Sub-Tenon's anaesthesia included infusion of a 3-4 ml mixture (50 : 50) of lidocaine 2%/mercaine 0.5%. General anaesthesia consisted of premedication with midazolam, followed by fentanyl, esmeron-bromate, propofol, and tracheal intubation. Duration of surgery and anaesthesia, intraoperative oculocardiac reflex and arrhythmias, time to discharge, postoperative pain, nausea and vomiting, and patient and surgeon satisfaction were evaluated.

RESULTS

The local anaesthesia group had a significantly shorter operative and anaesthesia time, fewer episodes of oculocardiac reflex or arrythmia/bradycardia requiring treatment, fewer early or late episodes of nausea and vomiting, and less pain. The patients and surgeon in this group reported higher satisfaction.

CONCLUSION

Propofol sedation with local sub-Tenon's injection of lidocaine/mercaine is recommended for the induction and maintenance of anaesthesia during unilateral or bilateral strabismus surgery in adults. The method is quick and effective, without systemic or ocular side effects.

Complications of ophthalmic regional blocks: their treatment and prevention

Complications following ophthalmic regional anaesthesia are rare but are reported during both needle (intraconal and extraconal blocks) and blunt cannula (sub-Tenon's block) techniques. At present there is no perfect technique of ophthalmic regional anaesthesia. This article reports on the complications, treatment and prevention of commonly used ophthalmic regional blocks. Thorough knowledge of the measures required to deal with complications when they occur are of paramount importance for safe clinical practice.

Injection intravitréenne accidentelle de lidocaïne au cours d’une anesthésie palpébrale : toxicité rétinienne de la lidocaïne ?

INTRODUCTION

We report an atypical case of scleral perforation due to an inadvertent intravitreal lidocaine injection following palpebral anesthesia. We discuss the management of this rare complication and focus on the transient lidocaine toxicity on human retina.

OBSERVATION

A 29-year-old man presented with unilateral decreased vision during a lower right palpebral anesthetic injection for a chalazion removal procedure. The patient's vision was light perception. Examination revealed intraocular pressure at 55 mmHg, a wound of the posterior crystalloid, an intraocular gas bubble, and a central retinal artery spasm. On ERG, the b wave was decreased. The central retinal artery spasm resolved with prompt reduction of hypertony. Twenty-four hours later, the vision was 6/10 and the ERG showed an increased b wave activity. No clinical retinal toxicity of lidocaine was observed. Only a subcapsular cataract was observed, which had caused the loss of vision.

CONCLUSION

This case confirms that lidocaine is well tolerated by the retina and reminds us that superficial palpebral anesthetic injection should be done with great caution.

Perforation du globe oculaire lors d'une anesthésie péribulbaire sous sédation par propofol

Sedation has been used widely for reducing patient anxiety during peribulbar block for ocular surgery. We report the case of a patient in whom a spontaneous move after injection of propofol for peribulbar block resulted in a globe perforation.

The Birmingham Eye Trauma Terminology system (BETT)

PURPOSE

To evaluate the international eye injury scene and design a standardized terminology for mechanical eye injuries.

METHODS

Surveys of practicing ophthalmologists and an extensive review of the international ocular trauma literature. Development of the Birmingham Trauma Terminology (BETT) using a logic-based approach.

RESULTS

BETT always uses the entire globe as the tissue of reference. Its well-defined terms encompass all types of mechanical eye injury. A one-to-one relationship exists between terms and clinical conditions.

CONCLUSION

BETT provides an unambiguous, consistent, simple, and comprehensive system to describe any type of mechanical globe trauma. Endorsed by several societies and peer-reviewed journals as the standardized international language of ocular traumatology, BETT is expected to become the preferred terminology for categorizing eye injuries in daily clinical practice.

Monitored anesthesia care for enucleations and eviscerations

OBJECTIVE

To report the technique and success of using monitored anesthesia care instead of general anesthesia for ocular enucleation and evisceration surgeries.

DESIGN

Retrospective, noncomparative interventional case series.

PARTICIPANTS

Twelve enucleated patients (Soparkar and Patrinely) and 146 eviscerated patients (Kulwin and Kersten).

METHODS

Surgical logs of two oculoplastic practices were reviewed searching for cases of ocular enucleations and eviscerations performed under monitored anesthesia care between 1990 and 2001. Identified hospital and clinic charts were then reviewed.

MAIN OUTCOME MEASURES

Monitored anesthesia care was deemed successful if (1) there were hemodynamic stability and complete analgesia intraoperatively; (2) there was absence of any chart documentation regarding patient or family psychological distress over the anesthesia method used; and (3) patients were discharged from the hospital without the need for observation or treatment > or = 23 hours.

RESULTS

Between 1990 and 2001, 146 eviscerations were performed under local anesthesia with monitored anesthesia care by two surgeons (RCK, DRK) as their routine practice pattern. In 1996, Drs. Soparkar and Patrinely began performing enucleations under monitored anesthesia care in selected cases, and from 1996 to 2001, these surgeons enucleated 12 patients under monitored anesthesia care. Four of the enucleated patients requested surgery without general anesthesia. The remaining eight patients had been refused surgery by at least one other specialist because of the patient's perceived high medical risk for complications under general anesthesia. In all 158 patients, the procedures were deemed successful by the preceding criteria.

CONCLUSIONS

This four-surgeon case series reports the successful use of local anesthesia with monitored care for ocular enucleation and evisceration procedures, offering several potential advantages over the traditional use of general anesthesia.

Inadvertent ocular perforation and intravitreal injection of an anesthetic agent during retrobulbar injection

We report the clinical management of a patient who sustained scleral perforation and intraocular injection of local anesthetic agent during retrobulbar block. We discuss the management options for this rare complication of local anesthesia in cataract surgery.

Ocular explosion after peribulbar anesthesia

We report 3 cases of globe rupture after peribulbar anesthesia. We discuss the predisposing factors, presenting features, and visual outcome after this complication. Globe explosion is a severe complication of inadvertent intraocular injection during peribulbar anesthesia. Visual outcome after vitrectomy is generally poor; however, cases that do not develop a retinal detachment may achieve good results.

Preoperative issues in adult strabismus

Preoperatively, strabismus surgeons need to obtain informed consent, identify any ocular or systemic risk factors, decide on the preferred method of anesthesia, and determine whether the patient is an appropriate candidate for an adjustable suture technique. Three major categories of complications should be listed on the consent form: Loss of vision, double vison, and need for reoperation. If a patient is at particulary high risk to have one of these complications, then the surgeon should emphasize this point during the preoperative discussion. The incidence of visual loss after strabismus surgery due to anterior segment ischemia, retinal detachment, or endophthalmitis is approximately 1 in 7,400 cases. The preferred method of anesthesia depends on the procedure planned, the age and general health status of the patient, and whether or not an adjustable suture technique is to be utilized. At the conclusion of the preoperative discussion, the patient should be well informed and comfortable with the choice or procedure, have reasonable postoperative expectations in terms of diplopia, and be prepared for any unexpected complications.

Visual-evoked potentials: assessment of retrobulbar and peribulbar anesthesia

PURPOSE

To assess the effects of retrobulbar and peribulbar anesthesia on nerve function as detected by visual-evoked potentials (VEPs).

SETTING

University hospital in southern Brazil.

METHODS

In a prospective study, 7 patients had peribulbar anesthesia and 9 had retrobulbar anesthesia for extracapsular cataract extraction. Visual-evoked potentials with pattern reversal and flash stimulation were performed at least 1 month before and 1 month after surgery. Study participants did not have ocular pathology other than cataract. The Lens Classification System III was used to grade the opacities before surgery.

RESULTS

No significant difference was found between preoperative and postoperative evaluations in VEP flash and pattern-reversal amplitude and latency in either group (P >.05). Postoperative amplitude and latency was not significantly different between the peribulbar and retrobulbar groups. Two cases in the peribulbar group had altered wave morphology without clinical manifestation postoperatively. All patients had a final best spectacle-corrected visual acuity of 20/20.

CONCLUSION

Block anesthetic procedures were safely used in cataract surgery, with no clinical sequelae to the optic nerve.

Retrobulbar versus systemic application of morphine during titratable regional anesthesia via retrobulbar catheter in intraocular surgery

IMPLICATIONS

We investigated the effects of morphine on postoperative pain in patients undergoing intraocular surgery using a new indwelling catheter. Although morphine produced central analgesic effects, there was no evidence for the involvement of peripheral opioid receptors in the modulation of ocular pain.

Altered globe dimensions of axial myopia as risk factors for penetrating ocular injury during peribulbar anaesthesia

We measured the range of equatorial horizontal widths (EHW) in axially myopic eyes and identified the sites of staphyloma using B scan echography. One hundred eyes in 50 patients were studied. The axial lengths (ALs) were sorted into five groups of increasing severity of myopia. The group mean AL, group mean EHW and the ratio of EHW/AL was calculated for each range. The results suggest that the increase in the AL in an axially myopic eye is associated with an increase in the EHW. However, this increase in the group mean EHW is relatively small (2.3 mm) compared with the increase mean AL (8.2 mm) across the entire range. The ratio of EHW/AL decreased with an increase in the group mean AL. Therefore, the increase in EHW in an axially myopic eye is unlikely to be a significant risk factor for inadvertent ocular injury for peribulbar injections if a careful single medial canthal approach is used. There was high incidence of staphylomas in eyes with AL > 29 mm, most were inferior to the posterior pole of the globe, and there were none at the equator.

Litigation in Canada against anesthesiologists practicing regional anesthesia. A review of closed claims

PURPOSE

To review the pattern of malpractice litigation related to regional anesthesia in Canada.

SOURCE

The Canadian Medical Protective Association (CMPA) provided with information about all anesthesia claims that closed in the years 1990-1997.

PRINCIPAL FINDINGS

In the period 1990-97 there were 7,909 closed legal actions involving all CMPA members (56,000). Of these, there were 310 cases involving anesthesiologists, of which 61 cases (approximately 20%) were related to regional anesthesia. Forty-two involved neuraxial blocks, and the legal outcome was favourable (dismissed or judgement in favour of the defendant doctor) in 37 claims. Nineteen claims involved peripheral nerve blocks. All these had favourable legal outcomes. Overall, 10% of regional anesthesia claims have unfavourable outcomes, compared with 28% of all anesthesia related claims and 30% of all CMPA members' claims. The degree of disability in the regional anesthesia claims were: none 10%; minor 49%; major 36%; catastrophic 5%. There were no deaths in the malpractice claims involving regional anesthesia, compared with 17% in the all anesthesia group and 11% in all members' claims.

CONCLUSION

Twenty percent of all anesthesia claims in Canada are related to regional anesthesia. The legal outcome of these claims is favourable in 90%. Unfavourable clinical outcome is associated with catastrophic or major injury. There were no deaths in the regional anesthesia claims.

Sub-Tenon's injection for local anesthesia in posterior segment surgery

OBJECTIVE

To determine whether the sub-Tenon's parabulbar approach for local anesthesia is a safe and effective choice for posterior segment surgery.

DESIGN

Prospective, noncomparative case series.

PARTICIPANTS

Two hundred seventy-six consecutive patients underwent posterior segment surgery at the University of Texas Medical Branch.

INTERVENTION

Two hundred patients received sub-Tenon's parabulbar anesthesia containing an 11 -ml mixture of 5-ml 2% lidocaine (Xylocaine), 5-ml 0.5% bupivacaine (Marcaine), and 1 ml of 150 hyaluronidase (Wydase) units as primary anesthesia. The method did not involve a separate transcutaneous lid nerve or subconjunctival injection.

MAIN OUTCOME MEASURES

The proportion of cases receiving supplementation (significant intravenous anesthesia, intraoperative local anesthesia, or both) was estimated. Its relationship to duration of surgery and surgical procedures deemed painful was assessed. Surgery lasting 3 hours or more was considered a long duration. Both scleral buckle and cryotherapy were considered painful procedures. The proportion of cases receiving additional local anesthesia preoperatively was also evaluated. Complications associated with sub-Tenon's parabulbar injection were monitored.

RESULTS

There were 101 instances of patients receiving additional anesthesia. Nineteen received additional preoperative sub-Tenon's anesthesia, 12 received intraoperative local anesthesia supplementation, and 70 received intravenous medication. Of these 70, 19 required what the authors defined as a significant amount of intravenous medication, three of whom also received intraoperative local anesthesia supplementation. Consequently, 28 of 200 patients (14%; 95% confidence interval: 9.5, 19.6) received supplementation (significant intravenous anesthesia, intraoperative local anesthesia, or both). The proportion of cases receiving supplementation was directly related to duration of surgery. Patients involved in longer cases (51.7% vs. 7.6%; P < 0.001) and those involved in more painful procedures (48.2% vs. 8.7%; P < 0.001) were more likely to receive supplementation. Adjusting for surgery duration, a greater proportion of patients undergoing painful procedures required supplementation (31.3% vs. 0.5% for surgery < 3 hours, P = 0.003; 72.7% vs. 38.9% for surgery > or = 3 hours, P = 0.13). No associated ocular or systemic complications were observed.

CONCLUSIONS

The results of this large study demonstrate that a single injection of sub-Tenon's anesthesia is relatively safe and effective for achieving local anesthesia during vitrectomies, with or without other intraocular procedures, lasting less than 3 hours. Other types of posterior segment surgery may require supplementation if they are more painful procedures, such as scleral buckle or cryotherapy, or last longer than 3 hours.

Ocular explosions from periocular anesthetic injections: a clinical, histopathologic, experimental, and biophysical study

OBJECTIVES

An increasing number of cases are being recognized in which a periocular anesthetic for cataract surgery has been inadvertently injected directly into the globe under high pressure until the globe ruptures or "explodes." The objectives of the current study were to (1) analyze this injury clinically and histopathologically through a series of seven case reports; (2) reproduce the injury experimentally in human eyebank eyes, live anesthetized rabbit eyes, and human cadaveric eyes; (3) investigate the biophysical basis of the injury; and (4) outline recommendations to help decrease the risk of ocular rupture with periocular injections. DESIGNS/PARTICIPANTS: Clinical, histopathologic, experimental animal, autopsy eye, and theoretical biophysical study.

METHODS

The clinical and histopathologic findings of the patients' eyes were documented. Human eyebank eyes, live anesthetized rabbit eyes, and human cadaveric eyes were exploded via direct intraocular saline injection. The laws of Bernoulli, LaPlace, Friedenwald, and Pascal were used to investigate theoretically the biophysics of the injury.

RESULTS

The findings of anterior and posterior scleral rupture, retinal detachment, vitreous hemorrhage, and lens extrusion were observed clinically and experimentally. In some clinical and experimental cases, the anterior segment appeared entirely normal despite a posterior rupture. The surgeon proceeded with and completed the cataract surgery in two of the seven clinical cases without knowledge of the rupture. The pressure required to produce such an injury is in the range of 2800 to 6400 mmHg, and this pressure is more easily attained with a 3-ml syringe than with a 12-ml syringe.

CONCLUSIONS

Explosion of an eyeball during the injection of anesthesia for ocular surgery is a devastating injury that may go unrecognized. The probability of an ocular explosion can be minimized by (1) the use of a blunt needle and a 12-ml syringe, (2) aspirating the plunger and wiggling the syringe before injection, (3) discontinuing the injection if corneal edema or resistance to injection is noted, and (4) inspecting the globe for evidence of intraocular injection before ocular massage or placement of a Honan balloon. On recognition of an ocular explosion, immediate referral to and intervention by a vitreoretinal surgeon is optimal.

Scleral perforation during retrobulbar and peribulbar anesthesia: risk factors and outcome in 50,000 consecutive injections

PURPOSE

To measure the frequency of scleral perforation and identify related risk factors during local anesthetic injection for intraocular surgery.

SETTING

Multispecialty eye hospital.

METHODS

All patients (n = 50,000) having retrobulbar (26,857) or peribulbar (23,143) injections at the King Khaled Eye Specialist Hospital were reviewed. Cases of scleral perforation were analyzed for potential technical and ophthalmic risk factors, management of injuries, and visual and anatomic outcomes. Mean follow-up was 14.4 months (range 8 to 24 months).

RESULTS

Seven (0.014%) needlestick injuries were identified, all of which had posterior staphyloma as the only identifiable risk factor. Applying a previously measured prevalence of 10.7% for posterior staphyloma in our surgery patients gave a scleral perforation rate of 0.13% (7 of 5350) for staphylomatous eyes. All perforated globes had originally planned cataract extraction within 8 weeks of injury. Additional management consisted of observation (2 cases), cryotherapy (2 cases), and vitreoretinal procedures for retinal detachment (3 cases) and subretinal hemorrhage (1 case). At last follow-up, all retinas were attached and 3 cases (42.8%) had a visual acuity of worse than 20/160. Both cases requiring multiple retinal detachment surgeries developed proliferative vitreoretinopathy and poor visual acuity.

CONCLUSIONS

Eyes with posterior staphyloma sustained needlestick injuries at a rate of 1 in 760 compared with 0 injection perforations in more than 44,000 nonstaphylomatous eyes.

The National Survey of Local Anaesthesia for Ocular Surgery. II. Safety profiles of local anaesthesia techniques

PURPOSE

To describe the adverse events associated with local anaesthesia (LA) for intraocular surgery.

METHODS

An observational study of practice of LA in the whole of the United Kingdom was conducted over 3 months in late 1996. Staff in all ophthalmology theatres in the National Health Service were invited to report every LA given for the purpose of intraocular surgery during the first week, and thereafter to report adverse events only.

RESULTS

During the first week, the reported incidence of all adverse events within the orbit was 2.7%, and for 'systemic' adverse events it was 0.9%. Serious adverse events were reported in association with all LA techniques. In 3 months, 18 events were described as 'life-threatening' by respondents, and further patients were reported to have had epileptic fits or were transferred directly from the operating theatre to an intensive care unit. The voluntary nature of the survey introduces some bias from under-reporting, making the incidence of these severe events difficult to assess. Reported incidence of severe 'systemic' adverse events was similar for all LA techniques.

CONCLUSIONS

Serious adverse events were reported in association with with all LA techniques. This implies that we should be prepared for such events in all patients who have intraocular surgery.

Local anaesthesia for vitreoretinal surgery: a case-control study of 200 cases

PURPOSE

In the United Kingdom the majority of vitreoretinal (VR) surgery is performed under general anaesthesia (GA). The aim of this study was to demonstrate the scope of local anaesthesia (LA) for VR surgery, to measure the acceptance of LA to patients and surgeons and to compare the surgical outcomes, complication rates and duration of the surgical procedures under LA and GA.

METHODS

A case-control study was undertaken to compare 100 cases performed under LA with 100 matched cases performed under GA. The matching of cases was based on multiple criteria such as configuration and complexity of retinal detachment, the involvement of the macula, the number and site of retinal tears, presence and severity of proliferative vitreoretinopathy, experience of the surgeon and the type of the surgical procedure. A clinical audit was also carried out on 65 successive patients using a questionnaire to determine the acceptability of LA to patients and surgeons.

RESULTS

Anatomical and visual success rates, and intra-operative and post-operative complications, were similar in cases carried out under LA and GA. The mean duration of the surgery (excluding anaesthetic time) was significantly shorter for LA than GA procedures (p < 0.001). The acceptance for LA was high for both patients and the operating surgeons.

CONCLUSIONS

We found that VR surgery can be safely and efficiently performed under LA. Adoption of LA has increased our throughput.

Sub-Tenon's anesthesia with a retained catheter in ocular surgery of longer duration

A sub-Tenon's anesthesia technique was developed that is suitable for surgical procedures of longer duration. After application of a small amount of anesthetic agent in the standard manner, a thin polyethylene catheter is introduced under Tenon's capsule and fixated. The catheter is used to inject more anesthetic agent during the procedure. This anesthesia regimen provides unlimited time for surgery without the risks of losing anesthetic effect and without using a potentially toxic, long-term local anesthetic agent.

Inadvertent globe perforation during retrobulbar injection in high myopes

PURPOSE

To report ocular perforation that occurred during retrobulbar injection in 7 highly myopic eyes.

METHODS

Seven patients with a diagnosis of globe injury during retrobulbar injection for ocular anesthesia before cataract surgery were managed by vitreoretinal surgery. All injections were performed by ophthalmologists. The surgeon recognized the perforation in 4 cases at the time of injection. The preoperative vision was hand motion perception in 4 eyes and light perception in 3 eyes. All patients underwent vitreoretinal surgery because of the presence of vitreous hemorrhage and/or retinal detachment diagnosed by funduscopy or ultrasonography. At the time of surgery, all eyes had vitreous hemorrhage and 4 eyes had rhegmatogenous retinal detachment. The number of vitreoretinal procedures performed was: 1 procedure in 4 patients, 2 procedures in 2 patients, and 3 procedures in 1 patient. The period of follow-up ranged from 4 months to 4 years, averaging 20 months.

RESULTS

At the end of the follow-up period, the retina was attached in 6 patients. The postoperative vision was 20/400 in 3 eyes, finger counting in 3 eyes, and light perception in 1 eye.

CONCLUSION

Special care should be taken in retrobulbar injection of highly myopic globes, which have an increased risk of perforation. The functional outcome of surgical repair of these eyes was poor.