Single injection peribulbar anaesthesia. Total upper eyelid drop as an end-point marker

Minimum effective volume of local anesthetic in peribulbar block: does it differ with the eyeball axial length?

Background

Peribulbar Anesthesia (PBA) is a relatively safe method for cataract surgery. The anesthetic volume should be adjusted according to the axial eyeball length. Thus, using Minimum Effective Volume (MEV) of local anesthetic helps avoiding unnecessary volumes, preventing increases in intra-ocular pressure, and producing satisfactory conditions for cataract surgery. This study aims to determine the MEV90 of local anesthetics in relation to eye globe axial length in peribulbar blocks for cataract surgery.

Methods

Patients scheduled for cataract extraction under local anesthesia were divided according to their axial eyeball length; Group 1 included those with axial length from 22 to 24 mm, Group 2 included patients with axial length from 24.1 to 26 mm. The initial volume used was 7 mL of a solution of bupivacaine 0.5% (3 mL) + lidocaine 2% (3 mL) + hyaluronidase 150 IU (1 mL). The subsequent volumes were dependent on the response of the previous patient, by using a Bias Coin Design (BCD) and Up and Down Method (UDM) for MEV-90 determination.

Results

The study was concluded with 119 patients. Sixteen patients needed supplemental volume of local anesthetic in Group 1 and thirteen in Group 2. The MEV90 for Group 1 was approximately 5.82 mL (95% CI 5.6 to 5.87 mL) and 5.45 mL for Group 2 (95% CI 5.38 to 5.91 mL). No major complications were noted. There was a negative correlation between the effective volume of LA and eye globe axial length in both groups (p = 0.001).

Conclusion

The MEV90 of local anesthetics for peribulbar block show a strong and inverse correlation with eye globe axial length. This may help achieving an effective block with minimum complications.

Comparison of orbital muscle akinesia caused by rocuronium versus hyaluronidase mixed to the local anesthetic in single injection peribulbar block for cataract surgery

Background:

The aim of this study was to compare orbital muscle akinesia caused by rocuronium versus hyaluronidase when mixed with the local anesthetic in single-injection peribulbar anesthesia (PBA).

Patients and Methods:

Sixty patients were included in the study and subjected to cataract extraction using phacoemulsification technique with intraocular lens implantation. Group I received peribulbar block with 5 ml mixture of 30 IU/ml hyaluronidase and 2% lidocaine. Group II received peribulbar block with 5 ml mixture of rocuronium 5 mg and 2% lidocaine. The onset and duration of akinesia were assessed; the akinesia score at 2, 5, and 10 min was measured after injection. The need for supplementary injection was also recorded.

Results and Conclusion:

PBA using a mixture of rocuronium and lidocaine provides optimal globe akinesia and faster establishment of suitable conditions to start eye surgery and shortens the block onset time as compared with the addition of hyaluronidase to lidocaine.

Effect of clonidine added to lidocaine for sub-Tenon's (episcleral) anesthesia in cataract surgery

PURPOSE

We aimed to evaluate the duration of anesthesia, analgesia and ocular akinesia of clonidine added to lidocaine in sub-Tenon's anesthesia in patients undergoing cataract surgery.

METHODS

Forty patients were prospectively enrolled. They were randomized to two sub-Tenon's anesthesia groups: group L (6 ml of lidocaine 2 %, 1 ml of 0.9 % saline and 25 UI/ml of hyaluronidase), and group C (6 ml lidocaine 2 %, clonidine 1 μg/kg, 1 ml of 0.9 % saline and 25 UI/ml of hyaluronidase). Duration of sensory anesthesia, ocular akinesia in all directions, akinesia of the levator palpebrae superioris and orbicularis oculi muscles, the duration of analgesia (time to the first postoperative use of analgesics), the overall use of analgesics and the presence of adverse effects were recorded .

RESULTS

The duration of sensory anesthesia and akinesia of the four rectus, levator palpebrae superioris, and orbicularis oculi muscles was significantly longer in group C (p < 0.05). The number of patients who required analgesics was similar between the groups but the duration of analgesia was longer in group C (p < 0.05). No significant adverse effects were observed.

CONCLUSION

The addition of clonidine 1 μg/kg to 2 % lidocaine in sub-Tenon's anesthesia for cataract surgery increased the duration of sensory anesthesia, ocular akinesia, and the duration of analgesia.

Transconjunctival approach to peribulbar block

As increasing numbers of anesthetists perform eye block anesthesia, thorough understandings of peribulbar injection techniques are important for safe practice. There is uncertainty in the literature regarding the optimum needle length, entry point, volume of injectate, and use of single vs double-injection techniques. A modified technique of peribulbar block anesthesia is presented, which offers increased safety, simplicity, low cost, and little change to instrumentation.

Satisfaction level with topical versus peribulbar anesthesia experienced by same patient for phacoemulsification

Background:

Various studies have assessed patient satisfaction with topical versus peribulbar anesthesia with conflicting results. Aim of study was to determine satisfaction level in same patient who gets topical anesthesia in one eye and peribulbar block in another eye. We propose that evaluation of various indicators of patient satisfaction will enable better selection of cases for topical anesthesia in the future.

Methods:

Eighty patients scheduled for phacoemulsification were enrolled in prospective, randomized, double-blind study. Each patient scheduled twice for one eye under topical anesthesia and other in peribulbar block. Pain, discomfort and pressure during application of local anesthetic, during phacoemulsification and at 2 hours after procedure were assessed on standard scales. Before discharge patient satisfaction level was checked with Iowa satisfaction with anesthesia scale (ISAS). The Student's t-test was used to determine the significance of IOWA score in both groups. P<0.05 was considered significant.

Results:

Feeling of pain, pressure and discomfort scores during administration of topical anesthesia were all significantly lower compared to peribulbar anesthesia (P=0.004, 0.000, 0.002, respectively). In contrast, intraoperative scores were significantly higher in the topical anesthesia group compared to peribulbar anesthesia (P=0.022, 0.000, 0.000, respectively). Patient satisfaction measured with ISAS shows that peribulbar anesthesia with P=0.000 is strongly significant.

Conclusion:

Peribulbar anesthesia provided significantly better patient satisfaction in comparison with topical anesthesia when used for cataract surgery.

Anesthesia for pars plana vitrectomy with insulin needle, is it possible?

Peribulbar block is commonly used for ocular posterior segment surgery. This work aimed to compare the efficacy of using 12.5 mm to 25 mm standard needle length in performing single injection peribulbar block for retinal surgery. Peribulbar block was performed in 120 patients using either standard 25 mm or 12.5 mm 30 G needle (insulin needle). While applying digital pressure around the needle hub, 8–10 mL of local anesthetic are injected. Ocular movement was assessed at 5 and 10 min using simple akinesia score (0–8). If after 10 min score was >1, supplementary injection was given. Visual analogue scale (0–10) was used at the end of the procedure to assess surgeons' satisfaction and patients' intraoperative pain. No differences in akinesia score at 5 & 10 min (P = 0.34 and 0.36, resp.). Initial volume injected was comparable between groups (P = 0.31), however total volume of local anesthesia and supplementary injections were significantly higher in 12.5 mm group (P = 0.03 and 0.01, resp.). No difference as regard surgeons' satisfaction and patients' intraoperative pain (P = 1.0 and 0.18, resp.). Peribulbar block with 12.5 mm needle together with digital compression is a suitable alternative to the standard block with 25 mm needle length for retinal surgery.

Comparison of levobupivacaine 0.5% or bupivacaine 0.5% both in a mixture with lidocaine 2% for superficial extraconal blockade

PURPOSE

To evaluate the quality and efficacy of Peribulbar blockade for superficial extraconal anesthesia with levobupivacaine 0.5% versus bupivacaine 0.5%, both combined with lidocaine 2% for patients undergoing phacoemulsification.

MATERIALS AND METHODS

In this prospective, double blind study, 150 patients were randomly divided into two groups: group-1 received a Peribulbar block (PB) with a mixture of evobupivacaine 0.5% and lidocaine 2% while group-2 received a PB with a mixture of bupivacaine 0.5% and lidocaine 2%. The block was performed by insertion of a short needle (15 mm) in infra-temporal space just above inferior orbital notch. An initial volume of 6 9 ml of either mixture was injected until total upper eyelid drop. Akinesia score was assessed at 2, 5, and 10 min after the block. The degree of pain was assessed by a verbal rating scale immediately after block, at the end of surgery and 4 h postoperatively. The patients and surgeons were asked to rate their satisfaction level of the quality of block postoperatively. Data were analyzed with the unpaired, two-tailed t-test and the Chi-square test as appropriate. P < 0.05 was considered statistically significant.

RESULTS

There were no significant differences between groups with respect to the akinesia score (P = 0.2) at 2, 5, and 10 min, the number of supplementary injections (P = 0.84) and initial and total required volume of local anesthetics (P = 0.80 and 0.81, respectively). There was no significant difference between the groups regarding surgeon and patient satisfaction (P = 0.53 and P = 0.74, respectively). Similarly the verbal rating scales assessed at three different occasions were not significantly different between the groups (P > 0.05 all cases). The need for additional intra-operative topical anesthetic was also similar between the groups. (P = 0.69).

CONCLUSIONS

Superficial extra-conal block with a mixture of levobupivicaine 0.5% and lidocaine 2% or bupivicaine 0.5% and lidocaine 2% provides similar block quality and efficacy.

The efficacy of 0.75% levobupivacaine versus 0.75% ropivacaine for peribulbar anesthesia in vitreoretinal surgery

BACKGROUND

We evaluated the anesthetic efficacy and the postoperative analgesic effects of 0.75% levobupivacaine versus 0.75% ropivacaine for peribulbar anesthesia in patients undergoing primary vitreoretinal surgery.

METHODS

We investigated 120 patients subjected to vitreoretinal surgery under peribulbar anesthesia. They were randomized into two equal groups according to the local anesthetic (LA) used, namely, 0.75% levobupivacaine or 0.75% ropivacaine, both with the addition of hyaluronidase. Nerve block was carried out by injection of 5-7 mL of the LA using single injection percutaneous peribulbar anesthesia with a short needle.

RESULTS

When compared with 0.75% ropivacaine, 0.75% levobupivacaine provided more successful akinesia at 10 min after block (P=0.026), fewer supplementary injections (P=0.026), and less volume (mL) was used (P=0.031). Also, levobupivacaine provided significantly longer motor block duration (342±27 min versus 206±40 min, P=0.001) and significantly longer sensory block duration (513±24 min versus 394±11 min, P=0.001) when compared with ropivacaine. In the postoperative period, the patients in the levobupivacaine group achieved lower values of verbal numeric rating scale of pain compared with patients in the ropivacaine group among the period from 4 to 12 h. Also, there were significantly (P=0.001) lower diclofenac consumption (mg) and the percentage of patients who required tramadol rescue medication were significantly less (P=0.034) in the levobupivacaine group compared with the ropivacaine group.

CONCLUSION

We are concluding that, at equipotent doses and concentrations, 0.75% levobupivacaine provides more effective peribulbar anesthesia and more effective postoperative analgesia for vitreoretinal surgery compared with 0.75% ropivacaine.

Single-injection percutaneous peribulbar anesthesia with a short needle versus sub-Tenon's anesthesia for cataract extraction

Purpose:

This study compared the efficacy of single-injection percutaneous peribulbar anesthesia (PBA) with a short needle with sub-Tenon's anesthesia (STA) to produce optimal operating conditions for cataract extraction in patients with complicated cataract.

Methods:

Two hundred patients with complicated cataract were enrolled in this prospective, double-blinded, randomized study. Adequate akinesia was a surgical requisite for all cases included in the study because of the expected difficult surgery. The patients were divided into two equal groups to receive either peribulbar anesthesia (PBA) with a 16-mm needle or sub-Tenon's anesthesia. Surgical akinesia (as a primary end point), analgesia, incidence of complications, as well as patient and surgeon satisfaction (as secondary end points) were assessed.

Results:

Both techniques provided similar analgesia during the operation and similar rates of incidence of chemosis with no serious complications; while the PBA group provided higher degree of akinesia 10 minutes after injection of the local anesthetic, a lower incidence of subconjunctival hemorrhage (SCH) and higher patient and surgeon satisfaction compared to the STA group.

Conclusion:

We concluded that when globe akinesia is necessary during surgery, the single-injection technique for percutaneous peribulbar anesthesia with a short needle proved to be more suitable than the STA in providing akinesia for cataract surgery. Also, this PBA technique demonstrated a lower incidence of SCH and was preferred to STA by the patients and surgeon.

Effect of pressure-reducing devices on the quality of anterior orbit anesthesia

Needle length is an important consideration in the safe conduct of ophthalmic blocks. A shorter needle could be used to insert the local anesthetic before the globe equator in the anterior orbit and to direct the injectable posteriorly using Honan's balloon to produce the desired effect. However, the use of pressure-reducing devices is not advisable in procedures with impaired retinal blood flow. The aim of this work was to demonstrate the effect of ocular compression with a Honan's balloon on the quality of peribulbar anesthesia when a short needle was used. The blockades were performed in 120 patients using a 27 G, half-inch-long needle. The needle was inserted into the inferotemporal quadrant adherent to the inferior orbital notch. The 7 to 10 ml of local anesthetic solution, consisting of bupivacaine 0.5%, lidocaine 2% in a ratio of 3:2 with hyaluronidase 5 U/ml, was injected followed by application of Honan's balloon or no compression. Ocular akinesia was assessed 10 min later; if inadequate, supplementary anesthesia was provided. No difference was detected in terms of volume injected, supplementation, and akinesia score. Under the conditions of this study, Honan's balloon did not contribute to the quality of the anterior orbit anesthesia, and the technique can be successfully used when ocular compression is contraindicated.

Superficial extraconal blockade for vitreoretinal surgery

Context:

Needle length plays an important role for the success of ophthalmic block. The standard practice is to use 25 mm needles length; however, unnecessarily long needles may increase the risk of complications especially in the presence of staphyloma or previous scleral buckle.

Aims:

This work was designed to compare the efficacy of using 15 and 25 mm needle in performing extraconal block for patients undergoing vitreoretinal surgery.

Settings and Design:

Prospective randomized double blinded study.

Materials and Methods:

A total of 120 patients were enrolled in this study and were divided in two groups. In group (1) extraconal block was performed using 25 mm needle, while in group (2) 15 mm needle was used. After primary injection, assessment of the block was done by an anesthesiologist who was unaware of the needle used. If satisfactory akinesia was not achieved a supplementation was provided. At the end of the procedures, patients and surgeons were asked to assess their pain and satisfaction with the anesthetic technique.

Statistical Analysis used:

The sample size calculation using N-Quary version 4. Numerical and categorical data were analyzed using an independent sample, a two-tailed t-test, and chi-square test, respectively.

Results:

The volume of primary injectable was significantly higher in group 2. The two groups were comparable as regards total volume of local anesthetic, supplementation rate, akinesia, pain score, and surgeon satisfaction.

Conclusions:

Using 15 mm needle length to perform extraconal blockade for posterior segment procedures is equally effective to 25 mm needle.

Peribulbar blockade with a short needle for phacoemulsification surgery

BACKGROUND

Peribulbar blockade is still widely used for phacoemulsification surgery. The potential complications of this technique include central spread, globe perforation and retrobulbar hemorrhage. The 25 mm needle is the most common needle used to perform the block. The aim of this study was to demonstrate the efficacy of a 12.5 mm needle in performing peribulbar blockade for phacoemulsification surgery.

METHODS

After obtaining the hospital research and the Human Ethics Committees' approval, 200 patients undergoing the phacoemulsification procedure under local anesthesia were enrolled in this descriptive study. Peribulbar blockade was performed with a 27 G, 12.5-mm-long needle. The needle was inserted transcutaneously through the lower eyelid into the inferotemporal quadrant. Digital pressure was applied by the thumb and index fingers around the needle hub during injection. After negative aspiration, a local anesthetic solution was injected until total drop of the upper eyelid was achieved. Ocular akinesia was assessed 10 min after the block using the simple akinesia score. A score of 3 or less was accepted to provide adequate analgesia for the surgical procedure to be performed. If the block was inadequate for surgery after 10 min, supplementary anesthesia was provided using the same needle.

RESULTS

Adequate analgesia after the first injection was reported in 90.5% of the patients while 9.5% required supplementary anesthesia. There were no major sight or life-threatening complications.

CONCLUSION

Using a 12.5-mm-long needle for peribulbar blockade produced satisfactory results. This technique is effective for phacoemulsification surgery.

Preliminary experience of combined peri- and retrobulbar block in surgery for penetrating eye injuries

BACKGROUND AND OBJECTIVE

Regional anaesthesia has not been recommended as an anaesthetic method for penetrating eye injuries because it is suspected to aggravate the injury already present. After having successfully managed the treatment of a penetrating eye injury under combined peri- and retrobulbar block in an ASA IV patient, it was decided to evaluate this anaesthetic method further in the treatment of such emergency cases.

METHODS

Twenty adult patients with penetrating eye injuries with a maximum wound length of 8 mm extending up to 4 mm posteriorly from the limbus were operated on under combined peri- and retrobulbar anaesthesia. Eighteen patients receiving general anaesthesia served as controls.

RESULTS

The mean (range) volume injected for a satisfactory peribulbar retrobulbar block was 7.4 (6.5-8.0) mL, six patients needed an additional retrobulbar injection before surgery (2.9, range 2-4, mL). All patients receiving regional anaesthesia were satisfied with the anaesthetic method and the surgeons considered the surgical conditions as good. No problems relating to local anaesthesia were observed or reported by any of the patients.

CONCLUSIONS

In the hands of an experienced anaesthesiologist and under certain conditions, regional anaesthesia appears to be suitable for adult patients having penetrating eye injuries.

Whatʼs new in ophthalmic anaesthesia?

PURPOSE OF REVIEW

There have been many changes in ophthalmic anaesthesia in the past few years. This review charts recent trends in practice.

RECENT FINDINGS

Topical anaesthesia is gaining widespread use for ophthalmic surgery, but readers need to be aware that definitions vary widely; some 'topical' techniques also include intracameral injections and adjunctive sedation. There is now evidence on the relative effectiveness of different types of local anaesthesia from large systematic reviews. Furthermore, the notion is emerging that the traditional distinction between peribulbar and retrobulbar blocks may not be as clear-cut as previously thought. A new area of investigation is the effect of local blocks on pulsatile ocular blood flow. However, the risk of ocular ischaemia has yet to be quantified. Local anaesthesia has also been tried for posterior segment surgery with apparently successful results. The management of patients taking anticoagulants and anti-platelet agents has been examined, and it appears that there are risks not only in continuing therapy but also in stopping it peri-operatively. The decision thus has to be taken on the balance of risks.

SUMMARY

There have been significant further gains in our understanding of local anaesthetic eye blocks and the management of patients undergoing such procedures.