Peribulbar anesthesia: a percutaneous single injection technique with a small volume of anesthetic

TRANSCARUNCULAR DOUBLE INJECTION TECHNIQUE FOR PERIBULBAR ANESTHESIA IN VITREORETINAL SURGERY

PURPOSE

Local anesthesia is commonly adopted in vitreoretinal surgery to reach painless and akinesia surgical condition. Currently, peribulbar anesthesia (PBA) and subtenon injection (STN) are the most widely used methods. We propose a transcaruncular double injection peribulbar technique (TRS) and aim to compare it with both standard PBA and STN injections.

METHODS

A total of 105 patients underwent TRS, PBA, or STN. A numerical rating scale was used to assess preoperative, postoperative, and intraoperative pain. Best akinesia score and onset and duration of akinesia were evaluated by two independent graders. The need for supplementary injection was also registered.

RESULTS

TRS group was characterized by a lower intraoperative numerical rating scale variation and absolute numerical rating scale score both at the beginning of surgery ( P 0.046), after 30 minutes ( P 0.032), and at the end of surgery ( P 0.002) compared with the other groups. The TRS group also showed better akinesia score ( P 0.004), fastest onset ( P 0.002), and longer duration ( P 0.042) compared with both PBA and STN. No injection-related complications were reported in the three groups.

CONCLUSION

The newly proposed transcaruncular PBA provided superior pain control and akinesia level with no additional adverse events.

Ultrasound-guided versus conventional peribulbar anaesthesia in cataract surgery: A randomised controlled study

BACKGROUND

Blind ophthalmic anaesthetic techniques may have serious complications.

AIM

To assess the safety of ultrasound as a guide in ophthalmic blocks.

METHODS

Fifty adult patients undergoing cataract surgery under peribulbar block anaesthesia were randomly assigned to ultrasound-guided and conventional block groups. In the ultrasound-guided block group, a large amount of the standard ultrasound gel was applied to the closed eyelids. The globes were scanned in both sagittal and transverse planes. The patients were asked to look straight ahead with closed eyes without clenching the eyelids. The depth and gain were adjusted before performing the block. The primary outcome was the rate of complications. Secondary outcomes included the volume of injected anaesthetics and surgeon and patients' satisfaction.

RESULTS

The local anaesthetic volume used was not significantly different between the two groups (7.08 ± 1.66 and 6.72 ± 1.97ml). The block onset, time and quality were comparable in both groups. No complications were reported, and there were no significant differences regarding surgeons' or patients' satisfaction with either procedure.

CONCLUSION

The ultrasound-guided local ophthalmic block is as safe as the conventional method. Although its use was not superior to the conventional procedure, direct visualisation with ultrasound may be important to avoid vulnerable structures such as staphylomas.

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.

Efficacy and Safety of Magnesium versus Dexmedetomidine as Additives to Local Anesthetic Mixture Using Single Injection Percutaneous Peribulbar Anesthesia in Vitreoretinal Surgeries

Background:

Peribulbar block for vitreoretinal surgery is rather associated with delayed onset of globe anesthesia, akinesia and short duration of analgesia.

Objective:

To compare the effect of addition of Magnesium sulphate vs dexmedetomidine to standard local anesthetics mixtures on the time of onset of Globe Anesthesia, Akinesia & analgesia duration.

Patients and Methods:

Ninety patients of both sexes, aged 25- 75 years, ASA I-III scheduled for vitreoretinal surgery. They were randomly allocated into 3 equal groups each received peribulbar block a mixture of Levo- bupivacaine 0.5% (3 ml) + lidocaine 2% (3 ml) +120 IU hyaluronidase + Control group (C): 0.5 ml of Normal saline. Group (M): 50 mg of Magnesium sulphate in 0.5 ml normal saline. Group (D): 50 μic of dexmedetomidine in 0.5 ml normal saline. The duration of sensory, motor block, Sedation level, Intra-ocular Pressure (IOP) and surgeon satisfaction were assessed.

Results:

The onset of globe anesthesia and akinesia was significantly shorter in M group in comparison with D and C Groups, with a significant increase in the duration of globe analgesia and akinesia in the D Group when compared to both M & C groups. Groups D and M showed a statistically significant decrease in the IOP at 5 min and 10 min when compared to the baseline measurement of the same groups & to C Group, no complications or adverse effects related to the drug or technique were recorded.

Conclusion:

Magnesium sulphate as a local anesthetic adjuvant in peribulbar block is safe and comparable to dexmedetomidine regarding the sensory and motor block duration with better cost-effectiveness and availability.

The Effect of Peribulbar Block with General Anesthesia for Vitreoretinal Surgery in Premature and Ex-Premature Infants with Retinopathy of Prematurity

Safe anesthesia in premature and ex-premature infants remains a challenge for the anesthesiologist. These infants are at risk of postoperative apnea, desaturation, and bradycardia after general anesthesia. We describe our experience of peribulbar block in 24 infants who underwent vitreoretinal surgery for retinopathy of prematurity. None of our patients had postoperative apnea or required neonatal intensive care admission. A possible opioid and muscle relaxant-sparing effect of peribulbar block might have reduced the incidence of postoperative 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.

Drug delivery in ocular diseases: Barriers and strategies

The eye is a complex organ made up of diversified cells with specified functions. Presence of anatomical, physiological and physiochemical barriers make it difficult to deliver drugs in therapeutic amounts at intended sites. To overcome these, drug delivery scientists have followed two distinct yet complimentary approaches. The first involves using alternate delivery routes to conventional ones allowing for more direct access to intended target sites. Second approach involves development of novel drug delivery systems providing better permeability, treatability and controlled release at target site. Combination of both these approaches are being utilized and optimized in order to achieve optimal therapy with minimal adverse effects.

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.

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.

Comparison between single-injection inferomedial and inferotemporal peribulbar blockades before cataract surgery

PURPOSE

To compare the efficacy and safety of single-injection inferomedial (IM) and conventional inferotemporal (IT) peribulbar blockades.

PATIENTS AND METHODS

This prospective randomized study included 200 patients who were randomly allocated into two equal groups (n = 100 patients); in the first group, patients received IM peribulbar injection (IM group), while IT peribulbar injection was performed for the second group (IT group). The measurement data were patient characteristics, number of patients who required supplementations, total anesthetic volume injected, surgeon's experience and any recordable complications.

RESULTS

The number of patients who required supplemental anesthetics due to inadequate block was significantly higher in the IT group (15 patients, 15%, vs. no patients, 0%, in the IM group). The total anesthetic volume injected was significantly lower in the IM group (5.6 ± 0.8 vs. 9.8 ± 0.7 ml in the IT group). Surgeon's satisfaction was significantly higher in the IM group (100 vs. 22% in the IT group). The incidences of complications were not significantly different between the two groups.

CONCLUSION

It is safe and effective to conduct single-injection IM peribulbar blockade using a small needle size and low anesthetic volume.

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.

Comparison of classic peribulbar anesthesia and new entry point (single percutaneous injection technique) in vitroretinal surgery

Purpose:

To describe the method that seeks to improve the administration of regional anesthesia for vitroretinal surgery avoiding the risk of potential complications associated with other techniques through comparison of safety and efficacy of classic peribulbar anesthesia versus single percutaneous technique using a prospective, randomized clinical trial.

Materials and Methods:

One hundred patients were randomized to classic peribulbar and single percutaneous peribulbar technique after informed consent. Pain during administration of anesthesia, during surgery was graded on a visual analogue pain scale and compared for both techniques. Globe akinesia, analgesia and IOP measurements before and after administration of anesthesia, detection of distribution of local anesthetic agent by ultrasound scanning and complications related were also compared.

Results:

Twenty out of 50 (40%) patients of group 1(classic pirebulbar) and 36/50 (72%) of group II (single percutaneous technique) experience no pain during administration of anesthesia. Scores for globe akinesia and anesthesia were less satisfactory in group 1 and supplemental blocks required in 8% of the patients while in group II all of the patients (100%) showed proper globe akinesia and anesthesia. There were significant elevation in mean IOP following injection in both groups and the incidence of subconjunctival haemorrhage, chemosis and echymosis were more frequent in group 1.

Conclusion:

Single percutaneous peribulbar technique proved to be a safe and efficient technique that offers excellent anesthesia and akinesia with less complication for various ophthalmic procedures