Regional anesthesia of the eye, orbit, and periocular skin

A mosquito proboscis-inspired cambered microneedle patch for ophthalmic regional anaesthesia

INTRODUCTION

One of the methods for pain management involves the use of local anesthesia, which numbs sensations in specific body regions while maintaining consciousness.

OBJECTIVES

Considering the certain limitations (e.g., pain, the requirement of skilled professionals, or slow passive diffusion) of conventional delivery methods of local anesthetics, developing alternative strategies that offer minimally invasive yet therapeutically effective delivery systems is of great concern for ophthalmic regional anesthesia.

METHODS AND RESULTS

In this study, a rapidly dissolving cambered microneedle (MNs) patch, composed of poly(vinylpyrrolidone) (PVP) and hyaluronic acid (HA) and served as a delivery system for lidocaine (Lido) in local anesthesia, was developed taking inspiration from the mosquito proboscis's ability to extract blood unnoticed. The lidocaine-containing MNs patch (MNs@Lido) consisted of 25 microneedles with a four-pronged cone structure (height: 500 μm, base width: 275 μm), arranged in a concentric circle pattern on the patch, and displays excellent dissolubility for effective drug delivery of Lido. After confirming good cytocompatibility, MNs@Lido was found to possess adequate rigidity to penetrate the cornea without causing any subsequent injury, and the created corneal pinhole channels completely self-healed within 24 h. Interestingly, MNs@Lido exhibited effective analgesic effects for local anesthesia on both heel skin and eyeball, with the sustained anesthetic effect lasting for at least 30 min.

CONCLUSIONS

These findings indicate that the mosquito proboscis-inspired cambered MNs patch provides rapid and painless local anesthesia, overcoming the limitations of conventional delivery methods of local anesthetics, thus opening up new possibilities in the treatment of ophthalmic diseases.

Transient unilateral exotropia after an infraorbital local anesthetic injection: a case report

We report a case of transient unilateral exotropia, a rare complication that occurred after an infraorbital local anesthetic injection, and present the possible mechanism underlying this adverse effect. A 64-year-old man underwent an excisional biopsy under local anesthesia for bilateral lower eyelid masses. He received a subcutaneous injection of a local anesthetic (a combination of 1:100,000 epinephrine and 2% lidocaine). Intraoperatively, we observed a homogeneous, fat-attenuated mass with thin fibrous septae inside the orbital septum of each eye. Following excision of the masses, the patient developed severe diplopia accompanied by exotropia, impaired adduction, and mydriasis of the right eye. The pupillary light reflex, visual acuity, and visual field test results were within normal ranges. Notably, his symptoms completely resolved 4 hours postoperatively without intervention. To our knowledge, transient unilateral exotropia following infraorbital local anesthetic injection is rare. The exotropia was attributed to diffusion of the epinephrine/lidocaine solution, which may have affected the ciliary ganglion and the medial rectus muscle. Caution is warranted during local anesthetic injections in patients who undergo periorbital surgery.

Effects of Humanized Nursing on Perioperative Glaucoma Patients under Local Anesthesia and Sleep Quality

OBJECTIVE

We assessed the effects of humanized nursing on perioperative glaucoma patients under local anesthesia and their sleep quality.

METHODS

Fifty glaucoma patients who underwent surgery under local anesthesia from January 2018 to January 2020 were enrolled and randomly divided into 2 groups (N=25). The control group received routine nursing care whereas the observation group underwent humanized nursing care. We compared negative emotion scores, treatment compliance, incidence of postoperative complications, comfort score, sleep quality score, and nursing satisfaction.

RESULTS

After nursing, the observation group had lower SAS and SDS scores than the control group (p < .05). The total treatment compliance rate was higher in the observation group than that in the control group (96.0% vs 72.0%, p < .05). The observation group had a lower incidence rate of postoperative complications than the control group (4.0% vs 24.0%, p < .05). After nursing, the observation group exhibited an increased GCQ score and a decreased PSQI score compared to the control group (p < .05). The total satisfaction rate of nursing was higher in the observation group than that in the control group (96.0% vs 76.0%, p < .05).

CONCLUSION

Humanized nursing for glaucoma patients during the perioperative period under local anesthesia is able to relieve the negative emotion of patients and enhance their treatment compliance, which is conducive to reducing postoperative complications, increasing physical comfort level, and ameliorating sleep quality, thereby improving nursing satisfaction by patients.

A New Two-Step Anesthesia for 23- or 25-Gauge Vitrectomy Surgery: A Prospective, Randomized Clinical Trial

OBJECTIVE

To investigate the safety and efficacy of topical anesthesia combined with subconjunctival anesthesia (termed two-step anesthesia) for 23- or 25-gauge pars plana vitrectomy or other posterior segment surgery.

METHODS

Patients (n = 90) requiring 23-/25-gauge vitrectomy or other posterior segment surgery were randomized into 3 groups. Group 1 received peribulbar anesthesia, group 2 received retrobulbar anesthesia and group 3 received two-step anesthesia. A 5-point visual analog pain scale (VAPS) was used to measure self-report of patient pain. Complications were recorded for subsequent analysis.

RESULTS

VAPS scores for overall intraoperative pain ranged from 0 to 3 (1.07 ± 1.07) in group 1, from 0 to 2 (0.69 ± 0.93) in group 2 and from 0 to 3 (1.06 ± 0.98) in group 3. Assessment of surgeon discomfort score ranged from 0 to 2 (0.31 ± 0.66) in group 1, from 0 to 3 (0.38 ± 0.82) in group 2 and from 0 to 2 (0.47 ± 0.62) in group 3. Both scores reveal no significant difference among the 3 groups. While there were no complications noted in group 1, there was an ocular perforation in group 2. Additionally, there were no complications in group 3 related to the anesthetic technique.

CONCLUSIONS

Results suggest that two-step anesthesia is a safe and effective anesthetic approach for selected patients undergoing 23- or 25-gauge pars plana vitrectomy or other posterior segment surgeries. It may offer a viable alternative to peribulbar anesthesia and retrobulbar anesthesia for carefully selected 23- or 25-gauge cannular-access ocular surgeries.

Compressive optic neuropathy secondary to an allergic reaction to hyaluronidase

A 58 year-old woman presented with severe chemosis and ophthalmoparesis on her left eye 8hours after uncomplicated cataract surgery under sub-tenon anaesthesia. Recovery of extrinsic motility was observed after corticosteroid and antihistamine treatment, but a non-haemorrhagic papillary oedema and a concentric defect of visual field were found. It progressed to papillary atrophy with preserved central vision, but with a significant visual field constriction. The aetiological study revealed an allergy to hyaluronidase that was used as adjuvant to the anaesthesia. This complication needs to be promptly diagnosed and treated, as the swelling of the orbital tissues can cause damage to the optic nerve.