Cannula-based 25-gauge vitreous tap and injection: a new surgical technique

In-clinic vitreous biopsy peel pack technique

BACKGROUND

Vitreous biopsy is a common technique used to guide management of acute endophthalmitis and help differentiate between infectious and inflammatory conditions. Currently, in-clinic vitreous biopsy is performed with a 25-gauge needle, without the ability to cut vitreous, potentially leading to reduced diagnostic yield. Recent work demonstrated the ability to perform vitreous biopsy with an off-the-shelf vitreous cutter. However, this was limited by complexity of assembly. Here, a technique using a single peel pack vitrectomy cutter is demonstrated for in-clinic vitreous biopsy.

METHODS

A 25-gauge vitreous cutter is opened from a peel pack. The drive line is identified, cut to length, and attached to a 10 mL syringe. A 1 mL syringe is attached to the aspiration line. After a trocar is used to place a cannula in the pars plana, the vitreous cutter is introduced into the eye. Cutting is performed by an assistant actuating the 10 mL syringe while the surgeon aspirates from the 1 mL syringe. After sample is collected, antimicrobials are injected if required and the cannula is removed.

RESULTS

A peel pack technique simplifies assembly for an in-clinic vitreous biopsy using a manually actuated cutter.

CONCLUSION

We present a novel, improved, and simplified technique for vitreous tap using a vitreous cutter provided in a single peel pack, actuated by a single syringe with minimal assembly prior to use. This technique may be more accessible for clinicians than prior techniques and does not require a surgical console.

In-Office Vitreous Biopsy With a Vitreous Cutter and Manual Actuation

In-office vitreous biopsy is currently performed with a 25-gauge needle or less frequently with a specialized in-office surgical system. This article demonstrates in-office vitreous biopsy with a standard vitreous cutter, using syringes to actuate the cutter. A 79-year-old woman presented six days after intravitreal bevacizumab with endophthalmitis. After subconjunctival anesthesia, a valved 27-gauge trocar was inserted through the pars plana. Two syringes were connected to a pneumatic 27-gauge Alcon vitrectomy handpiece and manually actuated by an assistant while the physician aspirated with a third syringe to obtain the vitreous biopsy. Intravitreal vancomycin and ceftazidime were injected. A total of 0.5 cc of fluid was collected without complications. Manual actuated vitrectomy reliably collects sufficient vitreous samples for diagnostic evaluation and may be safer and more effective than needle biopsy. [Ophthalmic Surg Lasers Imaging Retina 2024;55:116-118.].

One-port vs. three-port diagnostic vitrectomy for posterior segment diseases of unknown origin

PURPOSE

To compare the safety and the effectiveness of one-port vs. three-port diagnostic vitrectomy in undiagnosed cases of posterior segment inflammation.

METHODS

We retrospectively collected data from 80 consecutive diagnostic vitrectomies performed using a one-port (n = 40) or a three-port approach (n = 40). Cases of suspected postoperative endophthalmitis were not included in the study. Several variables were compared among groups, including length of surgery, postoperative best-corrected visual acuity (BCVA), diagnostic success and surgical complications.

RESULTS

The mean duration of surgery was shorter in the one-port group when compared to the three-port group (15 ± 8 min vs. 49 ± 30; p = 0.0001). The patients were observed for a mean follow-up of 19 months (range 1-84). In the one-port group, the mean BCVA improved from 1.31 ± 0.96 to 0.57 ± 0.59 logarithm of minimum resolution (LogMAR) (p = 0.0009). In the three-port group, BCVA improved from 0.98 ± 0.76 to 0.51 ± 0.76 LogMAR (p = 0.0005). The difference in mean postoperative BCVA between groups was not significative at the last follow-up. One-port vitrectomy yields to a final diagnosis in 80% of the cases, and three-port vitrectomy in 48%. Most of the one-port vitrectomies were carried out under topical anesthesia. After surgery, in both groups three eyes developed a retinal detachment.

CONCLUSIONS

In this pilot study, the one-port diagnostic vitrectomy has proven to be as effective and safe as the three-port approach, allowing a reduction in surgical times. One-port diagnostic vitrectomy might be considered as the first option for those cases where more complex surgical procedures are not needed.

Valved 25-Gauge Cannula for Vitreous Tap and Injection

BACKGROUND AND OBJECTIVES

To describe a technique that reduces patient discomfort by using a valved 25-gauge trocar for vitreous tap and intravitreal injection of medications in previously vitrectomized eyes with suspected infectious endophthalmitis.

PATIENTS AND METHODS

A commercially available 25-gauge valved entry system is used to enter the vitreous cavity. A 25-gauge needle attached to a syringe is used to obtain a vitreous specimen for microbiological access and administer intravitreal injections of antibiotics and steroids. No vitreous volume is lost during these procedures because of the cannula's valve. At the completion of the tap and injections, the cannula is removed with forceps and the single wound tamponaded with a cotton-tipped applicator.

RESULTS

With this method, a vitreous tap and injection of pharmacologic agents only requires one piercing through the sclera, instead of the usual four piercings.

CONCLUSION

With this new technique, it is possible to enhance patient comfort, decreased pain, and reduce trauma to the conjunctiva. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:916-917.].

25-GAUGE TROCAR CANNULA FOR ACUTE ENDOPHTHALMITIS-RELATED IN-OFFICE VITREOUS TAP AND INJECTION: Patient Comfort and Physician Ease of Use

PURPOSE

To assess comfort and procedural facility using a 25-gauge trocar cannula as a port to diagnose and treat acute endophthalmitis compared with a standard vitreous tap and injection technique.

METHODS

Eighteen consecutive patients with acute endophthalmitis were randomized into two treatment arms: 1) Standard vitreous tap and injection technique, and 2) A technique where a valved 25-gauge trocar cannula is inserted through the pars plana as done in sutureless vitrectomy surgery and subsequent vitreous sampling and injections are performed through the port. A standardized anesthetic protocol was used and subjects were masked to the technique performed. Primary outcomes measured were patient comfort using a Wong-Baker pain scale and standardized physician ease-of-use scoring scale. Secondary outcomes included vitreous sampling success rate and volume of vitreous sample.

RESULTS

No significant differences were found when comparing patient comfort (P = 0.340), physician ease-of-use scores (P = 0.796), vitreous sample volume (P = 0.149), successful vitreous taps (P = 0.620), and microbiologic yield (P = 1.000) between treatment arms. There were no adverse events.

CONCLUSION

The 25-gauge trocar technique provides a safe, well-tolerated, and equally effective alternative to the standard vitreous tap and injection technique for delivery of intravitreal antibiotics, and procuring of vitreous sample, requiring a single sharp penetration.

Experimental closed system surgical procedures and intraocular pressure fluctuation

PURPOSE

To determine the behavior of intraocular pressure and its relationship with infusion pressure in vitrectomy, phacofragmentation and phacoemulsification surgeries in rabbits.

METHODS

Intraocular pressure fluctuation was measured in 24 eyes of 12 rabbits submitted to vitrectomy, phacofragmentation and phacoemulsification procedures (eight eyes per group). The procedures were divided according to the force of aspiration of the instrument. Intraocular pressure was monitored with a computerized polygraph by means of a cannula introduced into the vitreous chamber.

RESULTS

Intraocular pressure showed a mean variation from 33 mmHg (maximum) to 6 mmHg (minimum). Vitrectomy showed the greatest difference between weak and strong aspiration. The greatest fluctuations occurred during procedures with strong aspiration, with phacoemulsification showing the widest variation, with maximum peaks almost reaching 50 mmHg. The infusion pressure varied less than the intraocular pressure, especially at the lowest pressures.

CONCLUSIONS

The fluctuation of intraocular pressure during ocular surgeries was not great. The higher the aspiration pressure, the higher the intraocular pressure. The infusion pressure did not show a good correlation with intraocular pressure.