A comparison of sub-Tenon’s with peribulbar anaesthesia in patients undergoing sequential bilateral cataract surgery

Role of hyaluronidase as an adjuvant in local anesthesia for cataract surgery

Cataract surgery ranks among the commonest procedures performed worldwide. Approximately 51% of blindness worldwide is related to cataracts, affecting about 65.2 million people worldwide and more so in developing countries. Over the years, there has been a significant evolution in the surgical techniques of cataract extraction. The advancement in phacoemulsification machines, phaco-tips, and the availability of ophthalmic viscoelastic devices have played a substantial role in cataract surgery such that they are faster and more controlled than before. Similarly, anesthetic techniques in cataract surgery have advanced significantly from retrobulbar, peribulbar, and sub-Tenon's blocks to topical anesthesia. Though topical anesthesia eliminates the possible complications of injectable anesthesia, it is not suitable for use in uncooperative, anxious patients, pediatric age groups, and patients with cognitive disabilities. Hyaluronidase is an enzyme that breaks down hyaluronic acid in the retrobulbar tissue, facilitating uniform diffusion of the anesthetic drug and hastening the onset of anesthesia and akinesia. Hyaluronidase has been used in the last 80 years successfully as an adjuvant in retrobulbar, peribulbar, and sub-Tenon's blocks. Initially, the hyaluronidase enzyme was animal-derived and of bovine and ovine sources. Recombinant human-derived hyaluronidase, which has lesser allergic reactions, impurities, and toxicity, is now available. There is conflicting evidence regarding the efficacy of hyaluronidase as an adjuvant in retrobulbar and peribulbar blocks. This article summarizes a brief review of the literature on the role of hyaluronidase as an adjuvant in local anesthetic blocks in ophthalmic surgeries.

Ophthalmic artery resistance index after peribulbar block in the presence of epinephrine

PURPOSE

There are controversies regarding ophthalmic artery (OA) flow after peribulbar block in the presence of epinephrine. Therefore, we aimed to evaluate OA flow via echo-Doppler before and after peribulbar block with lidocaine in the presence or absence of epinephrine.

METHODS

Fifty-six patients who had an American Society of Anesthesiologists (ASA) classification of I, II or III and were eligible for cataract phacoemulsification surgery were selected. Patients with other eye diseases were excluded. Patients were divided into two groups: group 1-peribulbar block with lidocaine and 1/200,000 epinephrine; group 2-peribulbar block with lidocaine in the absence of epinephrine. The resistance index (RI), peak systolic velocity (PSV), end diastolic velocity (EDV) of the OA were evaluated using echo-Doppler before and 10 min after the peribulbar block.

RESULTS

No differences between groups were observed in the RI before the peribulbar block as well regarding the presence of hypertension and the age or gender of the patient. After the peribulbar block, we observed a decrease in the RI in group 1 (p = 0.038, Cohen's d = 0.336) and no difference in the RI in group 2 (p = 0.109, Cohen's d = 0.172). When comparing group 1 and group 2, we observed a decrease in the RI in group 1 (p = 0.028, Cohen's d = 0,583). There was no difference between groups regarding the PSV and EDV after the peribulbar block.

CONCLUSIONS

A decrease in RI was observed in the OA after peribulbar block with a vasoconstrictor, an effect that could be a benefit in some ocular surgeries.

Comparison of Peribulbar with Posterior Sub-Tenon's Anesthesia in Cataract Surgery Among Nigerians

Purpose:

To compare the akinetic and the analgesic effects of peribulbar and posterior sub-Tenon's anesthesia in patients undergoing cataract surgery.

Methods:

In a hospital-based randomized comparative interventional study, patients aged 50 years and above who underwent elective surgery for uncomplicated cataract were randomized to receive either peribulbar block or posterior sub-Tenon block. Pain during injection, surgery, and after surgery was assessed using numerical reporting scale (NRS). Limbal excursion was measured with a transparent meter rule.

Result:

A total of 152 eyes of 152 patients were studied. Peribulbar and sub-Tenon regional blocks provided comparable adequate akinesia (P = 0.06) and similar levels of analgesia (P = 0.10) during cataract surgery. Both techniques also provided similar levels of analgesia to the patient during injection and in the immediate postoperative period. Ninety-two percent of patients who had peribulbar and 97% of those who had sub-Tenon blocks reported either mild pain or no pain at all during surgery (P = 0.49). There was no report of severe pain in all patients during the stages of the surgery. Occurrence of chemosis and subconjunctival hemorrhage was more common in sub-Tenon than peribulbar anesthesia.

Conclusions:

This study shows that peribulbar and posterior sub-Tenon routes of administering anesthetic substances is comparable in providing adequate akinesia and analgesia for cataract surgery with minimal complications. Therefore, both techniques are effective and safe for cataract surgery among Nigerians.

Local Anesthesia With Blunt Sub-Tenon's Cannula Versus Sharp Retrobulbar Needle for Vitreoretinal Surgery: A Retrospective, Comparative Study

BACKGROUND AND OBJECTIVE

To evaluate the safety and efficacy of a blunt sub-Tenon's cannula for local anesthesia before vitreoretinal surgery compared to a sharp retrobulbar needle.

PATIENTS AND METHODS

Retrospective, comparative study of all patients undergoing vitreoretinal surgery at the Medical College of Wisconsin between August 2009 and November 2013. Institutional review board approval was obtained.

RESULTS

Of 940 surgeries performed with a sub-Tenon's cannula, 99% (938 of 940) were completed. Of the 771 surgeries performed with a sharp retrobulbar needle, 99% (770 of 771) were completed. Factors associated with use of a sharp retrobulbar needle over sub-Tenon's cannula were presence of prior scleral buckle (P < .01) and inclusion of scleral buckle placement in the procedure (P < .01). No case of globe perforation, severe retrobulbar hemorrhage, or severe conjunctival chemosis was observed in either group.

CONCLUSION

Blunt sub-Tenon's cannula appears as effective and safe as a sharp retrobulbar needle for local anesthesia during vitreoretinal surgery. Vitreoretinal surgeons may wish to consider a blunt sub-Tenon's cannula for local surgical anesthesia.

Systematic Review of Peribulbar Anesthesia Versus Sub-Tenon Anesthesia for Cataract Surgery

Commonly used anesthetic techniques for cataract surgery include peribulbar and sub-Tenon anesthesia. This evidence-based review compares these techniques, with a particular focus on patient comfort, akinesia, and anesthetic complications. A systematic search of the literature revealed that there is a paucity of robust evidence comparing sub-Tenon and peribulbar anesthesia. Based on the best available evidence, there is no significant difference in the efficacy of peribulbar compared with sub-Tenon anesthesia for cataract surgery; however, the potential complications of peribulbar anesthesia are more serious.

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.