Trocar Cannula Research Articles

The Glowport - Illuminated vitrectomy trocar cannulas.

The use of small-gauge trocar cannulas during transconjunctival sutureless pars plana vitrectomy (PPV) facilitates the smooth transition of instruments into the posterior segment and reduces trauma. However, room lighting is routinely dimmed during PPV, thereby making cannula visualization difficult and hence compromising efficient instrument exchange. We report the use of a frugal, fluorescent "glow-in-the-dark" ring placed over vitrectomy cannulas to visualize the cannula entry, thereby providing a smooth and efficient instrument exchange. We 3D-printed phosphorescent rings of optimum inner diameter to comfortably fit around the trocar cannula (The Glowport). Two such rings are fitted into the two trocar cannulas prior to surgery initiation. The cannulas are then passed via sclerostomy as performed in routine PPV. The light from the fiberoptic endo-illuminator is focused over the rings for approximately 5 seconds to activate the photoluminescence. Under mesopic conditions, the fluorescence provides visualization of the cannula entry and helps in the facilitation of smooth entry and exchange of instruments into the globe for performing vitreoretinal surgical procedures, which helps in reducing ocular touch errors as well as surgical time. The Glowport is a frugal device retrofitted onto the trocar cannulas and helps in the smooth entry and exchange of instruments under darkroom conditions, which are required in vitreoretinal surgery.

Early Drainage of Suprachoroidal Hemorrhage Combined with Surgical Correction of Hypotony after Trabeculectomy.

Delayed suprachoroidal hemorrhage (DSCH) is a vision-threatening complication of intraocular surgeries with a higher prevalence in postglaucoma filtering surgeries. Through these case series of trabeculectomy complicated with DSCH, we aim to emphasize that correction of hypotony (inciting factor) is fundamental for complete resolution and prevention of recurrence. All three glaucoma patients underwent trabeculectomy surgery followed by DSCH on postoperative day 1. Drainage of DSCH using a 23 gauge trocar cannula within 48 hours of onset was performed along with exploration for the cause of hypotony. All three patients had satisfactory visual and anatomical outcomes. Early drainage using 23 gauge trocar cannulas gives good results in DSCH. The cause of hypotony must simultaneously be corrected during the drainage of DSCH. Preventive measures against hypotony should be taken while doing glaucoma filtering surgery. Surgical exploration for the cause of hypotony must simultaneously be performed during drainage of DSCH. Primary preventive measures against hypotony and bleeding during glaucoma filtering surgeries, like the use of releasable sutures, viscoelastic in the anterior chamber, and discontinuation of anticoagulants, can be done. Early drainage using trocar cannulas gives satisfactory results in DSCH postglaucoma surgeries. Beri N, Verma S, Bukke AN, et al. Early Drainage of Suprachoroidal Hemorrhage Combined with Surgical Correction of Hypotony after Trabeculectomy. J Curr Glaucoma Pract 2024;18(1):23-27.

Novel trocar assisted intraocular lens and capsular bag complex fixation.

To describe the innovative technique of trocar-assisted intraocular lens (IOL) and capsular bag complex fixation. In this technique, initial pupil dilatation is achieved either with intracameral adrenaline or with the help of iris hooks. Automated anterior vitrectomy is performed in cases with vitreous prolapse. A 25 G trocar cannula is placed at the limbus through a paracentesis opposite the zonular dialysis area. The cannula lumen act as a guide to pass the double-arm polypropylene suture attached to the needle. This prevents any inadvertent corneal injury and acts as a perpendicular tract to pass the needle through IOL capsular bag complex. We performed this technique in 9 cases with an excellent outcome with a minimum of 3 months of follow-up. All patients had well-centred IOL. There was no incidence of corneal injury, Descemet membrane detachment, iris trauma, IOL tilt, decentration, dislocation, vitreous prolapse or retinal detachment. All patients achieved excellent visual acuity ranging from 6/12-6/6 postoperatively. The novel trocar-assisted IOL bag complex fixation technique is very effective and allows smooth IOL fixation in technically challenging cases with IOL subluxation. The trocar acts as a guide to prevent injury to the surrounding tissue, and IOL fixation is achieved with minimal manipulations in the anterior chamber. It also prevents the need for IOL explantation in these cases.

Postprocedural clinical and laboratory evaluation of sheep submitted to different intrabdominal pressures during laparoscopy

The sheep experimental model is increasingly being used in laparoscopy, and there is a need to ensure animal welfare during and after the procedures. Therefore, the present study aims to evaluate postprocedural clinical and laboratory variables of sheep submitted to different intrabdominal pressures during laparoscopy. Ten female nonpregnant healthy adult Santa Ines ewes (48.8 ± 5.6 kg) were randomly submitted to a crossover study using different intrabdominal pressures (IAPs): 0 mmHg (G1), 10 mmHg (G2), 12 mmHg (G3), and 15 mmHg (G4). They were anesthetized and mechanically ventilated (VT =15 ml.kg−1) with positive end-expiratory pressure (3 cmH2O) and FiO2 = 1.0. At the same time, pneumoperitoneum was induced and maintained by Hasson's trocar cannula attached to an insufflator with no invasive visceral intervention. Physical examination and malondialdehyde levels were gathered immediately before (T0), 24 h (T1), 72 h (T2), 7 days (T3), and 14 days (T4) after the procedure. Hematology variables and fibrinogen were gathered at T0, T2, and T3, while serum biochemistry at T0 and T2. In the group with 15 mmHg of IAP, fibrinogen concentration was above normal level suggesting a late inflammatory response that persisted for up to 7 days (610 ± 335 mg/dL); Malondialdehyde concentration persisted in ascending levels for up to 14 days (from 257.2 ± 136.5–369.7 ± 201.4 nM/g Hb), and the opposite was observed in other groups. White blood cell (WBC), neutrophils, lymphocytes, and N:L ratios increased above normal levels in 72 h post-procedure and returned to normal within 7 days, except in the group of 15 mmHg of IAP which the highest value was reached 7 days post-procedure. Alterations in clinical parameters were mild and within normal values for the specie and breed in all groups. Biochemical analysis for all parameters was within the normal range in all groups. Still, monitoring aspartate aminotransferase (AST) up to 7 days after laparoscopic procedures is advisable due to its 72 h increase. Although no significant clinical and hematological alterations were observed, biochemical alterations and oxidative stress were greater up to 14 days after the procedure in the group with 15 mmHg IAP.

The influence of prolonged instrument manipulation on gas leakage through trocars

BackgroundDuring laparoscopic surgery, CO2 insufflation gas could leak from the intra-abdominal cavity into the operating theater. Medical staff could therefore be exposed to hazardous substances present in leaked gas. Although previous studies have shown that leakage through trocars is a contributing factor, trocar performance over longer periods remains unclear. This study investigates the influence of prolonged instrument manipulation on gas leakage through trocars.MethodsTwenty-five trocars with diameters ranging from 10 to 15 mm were included in the study. An experimental model was developed to facilitate instrument manipulation in a trocar under loading. The trocar was mounted to a custom airtight container insufflated with CO2 to a pressure of 15 mmHg, similar to clinical practice. A linear stage was used for prolonged instrument manipulation. At the same time, a fixed load was applied radially to the trocar cannula to mimic the reaction force of the abdominal wall. Gas leakage was measured before, after, and during instrument manipulation.ResultsAfter instrument manipulation, leakage rates per trocar varied between 0.0 and 5.58 L/min. No large differences were found between leakage rates before and after prolonged manipulation in static and dynamic measurements. However, the prolonged instrument manipulation did cause visible damage to two trocars and revealed unintended leakage pathways in others that can be related to production flaws.ConclusionProlonged instrument manipulation did not increase gas leakage rates through trocars, despite damage to some individual trocars. Nevertheless, gas leakage through trocars occurs and is caused by different trocar-specific mechanisms and design issues.

Cardiorespiratory effects of different intraabdominal pressures in sheep: An experimental study.

Increased intraabdominal pressure (IAP) during laparoscopy can reduce venous return, but changes in respiratory system mechanics and their effect in left cardiac function are not well documented. This study evaluated the effects of different IAPs on respiratory mechanics and cardiac function in 10 healthy nonpregnant adult Santa Ines ewes randomly submitted to a crossover study using different IAPs: 0 mm Hg (G1), 10 mm Hg (G2), 12 mmHg (G3), and 15 mmHg (G4). Animals were anesthetized and mechanically ventilated (VT =15 ml/kg; positive end-expiratory pressure=3 cmH2 O; FiO2 =1.0). Pneumoperitoneum was induced by Hasson's trocar cannula. Variables were measured at INITIAL (IAP, 0 mmHg) and FINAL time points for each IAP after 1 h. At FINAL, driving airway pressure (ΔP,RS ), and percentage fraction of dead space (Vd/Vt) were higher in G3 and G4 than G1 (p=0.002, difference in means [MD] 4.60, 95% CI: 7.91-1.28, and p < 0.001, MD 5.4, 95% CI: 8.7-2.0; p=0.016, MD -9.5, 95% CI: -17.9 to -1.2; and p=0.027, MD -8.7, 95% CI: -17.1 to -0.4). The ejection fraction and fractional shortening were lower in G3 (p=0.039, MD -11.38, 95% CI: -0.07--22.68; p=0.015, MD -13.05, 95% CI: -1.74--24.36) and G4 (p=0.039, MD -9.94, 95% CI: -0.07 to -19.80; p=0.015, MD -11.43, 95%CI: -1.57 to -21.30, respectively) than G2. In G3, the maximum pulmonary flow velocity correlated negatively with ΔP,RS (r=-0.740; p=0.018), and Vd/Vt correlated positively with ΔP,RS (r=0.738, p=0.046). At IAP of 12 and 15 mm Hg impaired respiratory system mechanics, reduced left cardiac function and no change in maximum pulmonary artery flow velocity were detected. Therefore, respiratory mechanics should be monitored as an interplay to reduce left cardiac function.

Additive Manufacturing of a Miniature Functional Trocar for Eye Surgery.

Stereolithography is emerging as a promising additive manufacturing technology for a range of applications in the medical domain. However, for miniature, medical devices such as those used in ophthalmic surgery, a number of production challenges arise due to the small size of the components. In this work, we investigate the challenges of creating sub-millimeter features for a miniature, functional trocar using Stereolithography. The trocar cannula system is used in eye surgery to facilitate a passage for other instruments. A standard trocar consists of a hollow cannula and a flexible check valve. The research was performed in two stages: in the first stage we investigated the effect of different materials and print settings on the current design of the cannula and the valve separately, and in the second stage we used these findings to optimize the design and production process. After the first investigation, it became apparent that even though the dimensions of the trocar are within the feature size range of Stereolithography, all hollow features tended to fuse shut during printing. This effect appeared regardless of the materials or print settings, and can be attributed to refraction of the laser source. In order to circumvent this, we identified two potential strategies: (1) increasing the negative space surrounding features; and (2) decreasing the surface area per layer. By applying these strategies, we tested a new design for the cannula and valve and managed to 3D print a functional trocar, which was tested in an artificial eye. The design of the 3D printed trocar allows for further personalization depending on the specific requirements of both patient and surgeon. The proposed strategies can be applied to different applications to create miniature features using Stereolithography.

TWENTY-FIVE AND TWENTY-SEVEN-GAUGE SUTURELESS INTRASCLERAL FIXATION OF INTRAOCULAR LENSES: Clinical Outcomes and Comparative Effectiveness of Haptic Flanging in a Large Single-Surgeon Series of 488 Eyes.

To describe the clinical outcomes and surgical technique in transconjunctival sutureless intrascleral fixation of intraocular lenses, including the effectiveness of haptic flanging and peripheral iridotomy. Retrospective series of patients who underwent sutureless intrascleral fixation of three-piece intraocular lenses by a single surgeon. A total of 488 eyes were included in this study. Mean follow-up was 444 days. Mean preoperative best-corrected visual acuity was 20/355, and mean postoperative best-corrected visual acuity was 20/39 (P < 0.001). Intraocular lens dislocation occurred during the postoperative period in 67 (13.7%), with the majority (65.7%) occurring within 3 months after surgery. Dislocation occurred in 13 of 196 (6.6%) flanged haptics versus 54 of 292 (18.5%) unflanged haptics (P < 0.001). Reverse pupillary block occurred in 7 of 231 eyes (3.0%) without intraoperative peripheral iridotomy but only in 1 of 257 eyes (0.4%) with iridotomy (P = 0.0297). Other complications included haptic exposure (1.2%), retinal detachment (1.0%), and endophthalmitis (0.4%). This is the largest reported series of sutureless intrascleral fixation of intraocular lenses using trocar cannulas. This technique is an effective surgical option with low complication rates. The authors recommend that haptic flanging and peripheral iridotomy be performed in all cases.

Intra-operative control of positive vitreous pressure in a graded manner by pars plana sutureless, small gauge trocar-cannula.

The purpose of this paper is to delineate a technique of using a 23G, single, sutureless transconjunctival pars plana sclerotomy to facilitate anterior segment surgery in eyes with increased positive vitreous pressure (PVP) ascribe to predisposing or intraoperative factors. We have implemented this technique in five eyes when PVP was anticipated before the surgery because of risk factors or it was encountered during anterior segment surgery. Different case scenarios in which PVP occurs during the surgery comprising phacolytic glaucoma, corneal tear repair combined with cataract surgery with IOL in a case with traumatic corneal injury, anterior capsule rupture and secondary glaucoma, Trabeculectomy in case of uveitic glaucoma, routine phacoemulsification cataract surgery with PVP encountered during surgery were addressed by using this technique. The new technique outlined by the authors consists of passing sutureless 23 G trocar cannula which enables controlled and gradual efflux of clear watery fluid, resulting in passive vitreous decompression with minimal risk of vitreous traction and retinal breaks. Once PVP is reduced, anterior segment surgery can be safely completed without risk of developing devastating complications. This sutureless single port pars plana trocar cannula technique is minimally invasive, safe, effective and fast technique which can cause reduction of PVP intraoperatively in a controlled and graded manner, thereby minimizing complication rates in difficult case scenarios.

A Stepwise Approach to the Surgical Management of Hemorrhagic Choroidal Detachments.

This work describes a stepwise surgical approach to draining choroidal detachments and 2 cases for which this approach was used. The first step involves insertion of an anterior chamber maintainer and a nonvalved 23- or 25-gauge trocar cannula at the highest peak of hemorrhagic choroidal detachment (as determined using B-scan ultrasonography), 6 to 8 mm from and angled 20° to 30° toward the limbus. The second step involves removal of the trocar to expose the sclerotomy. Alternatively, the second step can be insertion of a second trocar. The third step involves the creation of a small focal peritomy around the preexisting sclerotomy and enlargement of the preexisting sclerotomy into a radial sclerotomy. Progression between steps only occurs if prior steps did not provide adequate drainage. Two cases of appositional hemorrhagic choroidal detachments in hypotonic eyes were successfully resolved by this stepwise approach. In case 1, a choroidal detachment developed after a corneal ulcer perforation. The hemorrhagic choroidal detachment in case 1 was resolved with steps 1 and 2, and an unnecessary scleral cutdown was avoided. In case 2, a choroidal detachment developed after a trabeculectomy. The detachment in case 2 required progression to step 3, extension of the trocar insertion site into a radial sclerotomy. This stepwise approach should be considered to reduce excessive manipulation of the globe and conjunctiva in hemorrhagic and serous choroidal detachments that warrant surgical intervention.

Chandelier-assisted pneumatic retinopexy for rhegmatogenous retinal detachment repair in young adults.

We describe the new technique of chandelier-assisted pneumatic retinopexy in repairing rhegmatogenous retinal detachments in a series of young adults. In the operating room, a 25-gauge trocar cannula is inserted at the pars plana 180° across the preoperatively detected retinal break followed by Chandelier light insertion, which is used in globe fixation and rotation. The retinal periphery is reexamined using scleral indentation and chandelier light endoillumination. Transconjunctival cryopexy is performed around the break followed by paracentesis and pure sulfur hexafluoride gas injection. Twelve eyes of 12 patients were repaired. Their mean (±SD) age was 29.4 (±3.4) years and preoperative corrected distance visual acuity (CDVA) was 0.36 (±0.32). Nine eyes had 1 break while 3 eyes had 2 breaks within 1 clock hour. Mean duration of operation was 11.7 (±1.8) min. No patient experienced major intraoperative complications, but one patient required reoperation. Mean CDVA 6 months postoperatively was 0.63 (± 0.21) (p < 0.05).

Microincision vitrectomy surgery: experimental visualization and quantification of vitreous contamination

BackgroundTo visualize and quantify vitreous contamination following microincision vitrectomy surgery (MIVS) using an experimental vitreous contamination model (EVCM).MethodsEnucleated porcine eyes with fluoresbrite carboxylate microspheres applied to the conjunctival surface were used as a type 1 EVCM. Twenty-five- or 27-gauge (G) trocar cannulas were inserted through the conjunctiva and sclera, followed by the placing and opening of an infusion cannula. These procedures were monitored by an intraocular fiber catheter. Secondly, condensed microspheres were applied to an excised sheet of porcine sclera to serve as type 2 EVCM. Twenty-five- or 27-G trocar cannulas were inserted perpendicularly through the top of the sclera where the condensed microspheres were applied, an infusion cannula was inserted, 0.1 mL of saline solution injected through the infusion cannula, and samples collected. The fluorescence strength of samples was then measured using fluorophotometry.ResultsWe visually detected fluorescent microspheres in 10/10 eyes with 25-G and 10/10 with 27-G MIVS. In the experimental quantification study, each MIVS gauge value was significantly higher than the control (P < 0.01). However, there was no significant difference between 25-G and 27-G MIVS.ConclusionsMIVS carries the risk of introducing contamination directly into the eyes when the trocar cannula is inserted and infusion cannula is opened, even when a 27-G MIVS is used. Our study has shown it is essential that the surgeon be aware of the possibility of introducing contamination from the conjunctiva at all times during MIVS.

Ab-interno surgical technique for the implantation of a wireless subretinal prosthesis in mini-pigs

We sought to describe the surgical techniques required in the ab-interno method to implant subretinal prostheses in mini-pigs and suggest tips to facilitate optimal outcomes. During vitrectomy, the use of valved trocar cannulas was essential to stabilize the detached retina and implanted chip. As a first step in retinal detachment, a 23-gauge cannula with very small amount of viscoelastic material was used to establish the retinal hole and promote retinal detachment. Then, balanced salt solution was applied to increase the retinal detachment and diathermy was used to make opening for subretinal prosthesis. For easy positioning of the subretinal prosthesis, a curved laser probe was adopted when handling the subretinal prosthesis under the retina. After surgery, the sclerotomy sites were tightly sutured to prevent silicone oil leakage. Without special equipment, such as a 41-gauge tip, retinal detachment could be induced easily, while the prosthesis was also successfully inserted and manipulated under the retina without an iatrogenic retinal tear. Two weeks after the operation, the oil fully occupied the intraocular volume without leakage. The subretinal prosthesis remained stable without complication. Understanding the principle of the ab-interno method and considering several tips for improving surgical access may help to enhance surgical success rates of subretinal prostheses implantation.

'Stop-and-Slide' technique for trocar insertion during lens-sparing vitrectomy for retinopathy of prematurity.

The modern-day trocar cannula systems meant for adult eyes pose a challenge in infant's eyes with stage 4 retinopathy of prematurity (ROP) undergoing lens-sparing vitrectomy. This is primarily owing to the length of the trocar, globular lens, smaller axial length, and anteriorly displaced retina. We describe an inexpensive modification of the technique of trocar insertion in such cases wherein the trocar is inserted partially till the cannula impinges the sclera and thereon, the cannula slides over the trocar into the vitreous cavity. This obviates the need for complete insertion of the trocar into the vitreous cavity and hence limits the chances of inadvertent injury to the crystalline lens or the anteriorly lifted retina. We have experience in using this technique in 52 eyes of 44 infants over the past 2 years with no episode of iatrogenic lens touch or retinal break during trocar insertion.

Sutureless intrascleral fixation using different three-piece posterior chamber intraocular lenses: a literature review of surgical techniques in cases of insufficient capsular support and a retrospective multicentre study.

We present a literature review of surgical techniques of intraocular lens placement in eyes with insufficient capsular support, focusing on the most recent publications, together with a retrospective multicentre consecutive case series analysis of 103 eyes undergoing pars plana vitrectomy and sutureless intrascleral (SIS) fixation of a standard three-piece PCIOL. Many different approaches appear in the literature without any specific procedure achieving superior outcomes. Advantages and disadvantages vary between techniques. Common complications related to IOL fixation techniques were as follow: anterior chamber IOL: transient/permanent corneal oedema (9-66.6%), uveitis (1.1-39.3%); iris-fixated IOL: pupil ovalization (16-47.7%); and sutured scleral-fixated IOL: suture breakage/exposure (6.1-11%), vitreous haemorrhage: (5.5-16.6%). In our retrospective case series, indications for surgery were postoperative aphakia in 50 eyes (49%), IOL dislocation in 38 eyes (37%) and natural lens dislocation in 15 eyes (14%). Scleral tunnels for haptic fixation were created with (28 eyes, 27.2%) or without (75 eyes, 72.8%) 25 gauge trocar cannulas. Complications included transient hypotony (n=20; 19.4%), corneal decompensation (n=7; 6.7%), IOL dislocation (n=6; 5.8%), cystoid macular oedema (n=5; 4.8%), vitreous haemorrhage (n=4; 3.8%) and retinal detachment (n=4; 3.8%). Mean best corrected visual acuity improved from logMAR 0.65 to 0.36 at the final visit (p=0.001). In conclusion, SIS fixation provides good anatomical and functional outcomes; however, complications can occur. The number of surgical approaches for IOL dislocation described in the literature indicates that optimal treatment remains to be found.

27-GAUGE SUTURELESS INTRASCLERAL FIXATION OF INTRAOCULAR LENSES WITH HAPTIC FLANGING

To determine whether haptic flanging during 27-gauge sutureless intrascleral fixation of intraocular lenses (IOLs) increases IOL stability and to report the short-term clinical outcomes of sutureless intrascleral surgery using 27-gauge trocar cannulas with haptic flanging. Retrospective surgical case series using live and cadaveric human eyes. In the cadaveric experiment using five eyes, flanged haptics required more force to dislocate the IOL compared with unflanged haptics (14 ± 4 vs. 3 ± 1 g, P = 0.03). The clinical series included 52 eyes from 52 patients. The average age at the time of surgery was 73 ± 14 years, with a mean follow-up of 27 ± 19 weeks. The most common indication for surgery was IOL dislocation/subluxation (n = 43, 83%). Mean visual acuity improved from 20/140 preoperatively to 20/50 at postoperative Month 1 (P < 0.001). The most common postoperative issue was intraocular pressure elevation (n = 12, 23%). Two patients (4%) needed a reoperation for IOL dislocation. Haptic flanging during 27-gauge sutureless intrascleral surgery creates a more stable scleral-fixated IOL compared with the traditional unflanged technique based on a cadaveric human eye study. In addition, this variation of sutureless intrascleral surgery seems safe and effective for patients who require secondary IOLs.

Laparoscopic entry techniques: What is the controversy?

To review reported complications related to the different laparoscopic entry techniques in the human and veterinary literature and describe the benefits and limitations of each technique. Literature review of 57 peer-reviewed articles. An electronic database search identified human and veterinary literature describing complications related to entry technique during laparoscopy. Open- and closed-entry techniques may result in trauma of abdominal organs or vasculature. During laparoscopy in man, injury to bowel and major vasculature is reported in 0.02% and 0.04% of procedures with open- or closed-entry techniques, respectively. Designs of Veress needles and trocar cannula assemblies have been developed to improve ease and safety. Early complications, defined as those observed at the time of port entry into the abdominal cavity, result from the puncture of a blood vessel leading to substantial visible hemorrhage. Late complications are detected 24 or 48 hours after surgery and result from the puncture of a loop of intestine that was not detected at the time of initial surgery. The major reasons for iatrogenic trauma in man are related to anatomical factors and the presence of adhesions. No explanation for cause of complications was identified for animals. There is no consensus in the human or veterinary literature about the best entry technique for laparoscopy. The rate of complications related to entry technique in small animals is not known because the data are underreported. Complications related to entry techniques are expected in both man and animals. Improvements in techniques and equipment design are being developed to minimize risk.

Systemic Approach to Prevent Inadvertent Perfusion in Eyes with Extensive Choroidal Detachment, Suprachoroidal Fluid, and Hypotony During Pars Plana Vitrectomy.

IntroductionRhegmatogenous retinal detachment (RRD) with extensive choroidal detachment (CD), suprachoroidal fluid (SCF), and lower intraocular pressure (IOP) markedly increase the difficulty of pars plana vitrectomy (PPV) because it makes the insertion and placement of the trocar cannulas for PPV time-consuming and technically challenging. In this study, we developed a systemic approach that avoids the risks of sclerotomy or using a longer trocar to help in the safe placement of the trocar cannulas in order to prevent inadvertent fluid/air perfusion during PPV in RRD eyes with extensive CD, SCF, and hypotony.MethodsThis is a prospective case series study. Consecutive patients diagnosed with RRD with extensive CD, SCF, and hypotony were recruited. The main steps included injecting transconjunctival intravitreal fluid to increase IOP and enable the passive egress of SCF into the subconjunctival space, creating and broadening the inner opening for the trocar cannulas, transillumination with an endoillumination light pipe, and indentation of the infusion cannula to create maximum visual exposure of the inner segment and help peripheral shaving around the infusion tip. Main outcomes: the success rate of the infusion placement into the vitreous cavity, surgical duration, intra- and postoperative complications, and functional and anatomical outcomes.ResultsThirty-eight patients (38 eyes) were included. The first-time success rate of cannula placement into the vitreous cavity was 100%, with a mean surgical duration of 8.5 ± 1.8 min. No intra- or postoperative complications related to the approach were observed. Significant vision improvement was noted in 68.4% (26/38) of the patients at the final follow-up. The primary and final retinal reattachment rates were 94.7% (36/38) and 100% (38/38), respectively.ConclusionThis systemic approach is a feasible option to ensure the safe placement of trocar cannulas and prevent inadvertent perfusion during small-gauge PPV in RRD eyes with extensive CD, SCF, and hypotony, without the need for a draining sclerotomy, a longer trocar, or a sharp clearing of the cannula tip.

One-port vitreous cavity lavage with hybrid 27G infusion and 23G cannula.

To describe a new surgical technique for performing vitreous cavity lavage. After a 23G trocar cannula was inserted into the vitreous cavity at the lowest point of the eyeball 3.5 or 4 mm posterior to the limbus, a 27G infusion line with balanced salt solution was attached to the cannula. The infusion tube was partially withdrawn and the vitreous fluid with blood flowed out through the space between the larger lumen of the cannula and the smaller infusion tube. Meanwhile, vitreous cavity was irrigated with fresh balanced salt solution through the infusion line and the intraocular pressure (IOP) was maintained. The vitreous clarity was checked by indirect ophthalmoscopy. A total of 14 eyes of 14 patients with postvitrectomy hemorrhage were treated with the lavage technique. The vision improved and the fundus could be sufficiently viewed next day in all cases. This fluid/fluid exchange procedure was also performed in fluid/air exchange in two cases of unclosed idiopathic macular hole with switching to air infusion instead of balanced salt solution infusion. This minimally invasive technique is a simple, safe, and efficient way of performing postvitrectomy vitreous cavity fluid/fluid or fluid/air exchange.

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

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. 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. 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. 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.