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Year : 2023  |  Volume : 16  |  Issue : 1  |  Page : 18-22  

Evaluation of twenty-seven-gauge vitrectomy for complex proliferative diabetic retinopathy

Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India

Date of Submission25-Nov-2021
Date of Decision02-Apr-2022
Date of Acceptance29-Jun-2022
Date of Web Publication21-Feb-2023

Correspondence Address:
Vinod Kumar
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi - 110 029
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ojo.ojo_348_21

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PURPOSE: To evaluate the outcomes of twenty-seven-gauge (27G) vitrectomy in cases with complex proliferative diabetic retinopathy (PDR).
METHODS: This was a retrospective interventional study of eyes that underwent 27G vitrectomy for complex PDR. The demographic profile, history, examination findings, and intraoperative surgical steps (especially use of other instruments such as intravitreal scissors/forceps) were reviewed. All the eyes were followed up for a minimum of 3 months at 1-week, 1-month, and 3-month interval. Visual acuity, intraocular pressure (IOP), and retinal status were documented at every follow-up.
RESULTS: Nineteen eyes of 17 patients with complex PDR were included in the study. Seven eyes had tractional retinal detachment involving the macula, three had tractional retinal detachment threatening the macula, one had secondary rhegmatogenous retinal detachment, and eight eyes had nonresolving vitreous hemorrhage along with thick fibrovascular proliferation (FVP) at posterior pole. Anatomical attachment was seen in all cases at the end of follow-up with a single surgery. Visual acuity improved from logMAR 2.5 preoperatively to logMAR 1.01 at 3 months (P = 0.0003). None of the cases required use of intravitreal scissors/forceps for the removal of FVP. Early postoperative vitreous hemorrhage was seen in two eyes. Hypotony was not seen in any eye, while increased IOP was seen in five eyes.
CONCLUSION: 27G vitrectomy is a safe and effective technique in cases with complex diabetic surgery. Due to smaller size cutter, it offers advantages in the dissection of tissue and is associated with lower incidence of early postoperative hemorrhage.

Keywords: Diabetes mellitus, fibrovascular proliferation, pars plana vitrectomy, tractional retinal detachment, twenty-seven gauge

How to cite this article:
Verma S, Shiny H, Azad SV, Kumar V. Evaluation of twenty-seven-gauge vitrectomy for complex proliferative diabetic retinopathy. Oman J Ophthalmol 2023;16:18-22

How to cite this URL:
Verma S, Shiny H, Azad SV, Kumar V. Evaluation of twenty-seven-gauge vitrectomy for complex proliferative diabetic retinopathy. Oman J Ophthalmol [serial online] 2023 [cited 2023 Mar 31];16:18-22. Available from: https://www.ojoonline.org/text.asp?2023/16/1/18/370053

   Introduction Top

Twenty-gauge (G) vitrectomy remained the gold standard for pars plana procedures for a long time since its introduction in 1971.[1] It revolutionized the field of retinal surgeries and led to significant improvement in surgical outcomes. Later, 25G suture-less vitrectomy system with self-sealing incisions was introduced by Fuji et al.[2] However, narrow bore resulted in decreased illumination, low flow rates, and increased flexibility and fragility of instruments. Hence, it was recommended chiefly for surgeries such as vitrectomy for simple vitreous hemorrhage and macular surgeries, which did not require complex maneuvers. Eckardt later introduced 23G vitrectomy, which is now widely used system as it offers a good balance between sturdiness and maneuverability.[3] Introduction of smaller gauge surgery has in general resulted in lower rate of intra- and postoperative complications and lesser discomfort to the patient.

Oshima et al. first introduced 27G vitrectomy in 2010.[4] With an incision size of 0.4 mm, a 1-step nonbeveled insertion technique is used with it. Due to flexibility of equipment, 27G is not a preferred modality for situations such as complex retinal detachments, giant retinal tears, and proliferative retinopathies, especially those with thick membranes. Although it is primarily used for simple vitrectomy and macular surgeries, its use has also been described in various other conditions including rhegmatogenous retinal detachment (RRD), proliferative diabetic retinopathy (PDR), and giant retinal tears.[5],[6],[7]

Contrary to limitations of 27G system, it may offer benefit over larger bore instruments in terms of its ability to enter small confined spaces. This may be particularly useful in complex PDR, where it may enter between multiple attachments of diabetic membranes. This is particularly true since vitreous cutter is the main instrument used for removing membranes nowadays. Therefore, we conducted this study to evaluate safety, efficacy, and outcomes of 27G vitrectomy for complex PDR.

   Methods Top

This was a retrospective study conducted at tertiary care center in North India. The study adhered to the tenets of the declaration of Helsinki and to the institutional research guidelines. Written informed consent was obtained from all the patients.

All cases of complex diabetic retinopathy including cases with tractional retinal detachment (TRD), combined RRD, fibrovascular proliferation (FVP), and vitreopapillary traction (VPT) who underwent 27G pars plana vitrectomy were reviewed. The inclusion criteria of the study were age >18 years; known diabetics with controlled blood sugar levels; and cases with or without vitreous hemorrhage with TRD, combined RRD, FVP, and/or VPT. The exclusion criteria for the study were any previous history of vitreoretinal surgery; previous history of any significant ocular trauma; and any ophthalmic comorbidity such as corneal opacities or nondilating pupil which would interfere with the surgery. Patients with minimum follow-up of 3 months only were included in the study.

All the details of the cases including history, systemic examination, and ocular examination including Snellen best-corrected visual acuity (BCVA), intraocular pressure (IOP), anterior segment examination, and ultrasonography were reviewed and data were collected. The details of surgery including all the steps and any intraoperative complications such as iatrogenic break or intraoperative bleeding were noted on the basis of intraoperative notes and careful review of surgical videos. Phacoemulsification with intraocular lens (IOL) implantation (foldable hydrophobic acrylic IOL) was performed in cases with cataract more than nuclear sclerosis Grade II and was noted. Postoperatively, the patients were examined on 1st day, 1 week, 1 month, and 3 months. BCVA and IOP with detailed anterior and posterior segment examination were performed at every follow-up. No antivascular endothelial growth factor injections were administered in this 3-month period. The BCVA was converted to logarithm of minimum angle of resolution. All the data were entered into the Excel sheet and statistical analysis was performed using Student's t-test. P < 0.05 was considered statistically significant.

Surgical procedure

A single surgeon (VK) operated all the eyes under peribulbar block (50% solution of 2% lignocaine with 0.75% bupivacaine) using twenty-seven-gauge (27G) instrumentation on Constellation Vision System (Alcon Laboratories, Inc., Fort Worth, TX, USA). Conjunctiva was displaced from the intended site of entry and trocar was inserted at an oblique angle about 3–4 mm posterior to the limbus to avoid the overlap between scleral and conjunctival wound. After making three ports, core vitrectomy was done using 7500 cuts/min and linear aspiration of 0–600 mmHg. An “outside-in” approach was used in most cases, where the posterior hyaloids was truncated outside the area of posterior pole. The dissection was then continued toward the posterior pole using a combination of segmentation and delamination method. Bleeders were diathermized to avoid any excessive bleed. Internal limiting membrane (ILM) peeling was done in cases where retinal striae/macular edema were present at the macula. If there were retinal breaks, they were used for fluid air exchange. Panretinal photocoagulation was completed in all the eyes. Tamponade was provided at the end of surgery with 16% SF6 or air depending on surgeon's discretion. The sclerotomy sites were inspected for any leakage. The patients were prescribed a standard regimen of postoperative topical steroids, antibiotics, and cycloplegics.

   Results Top

Nineteen eyes of 17 patients were included in the study. The age group of patients ranged from 27 to 75 years with a mean age being 53.5 years and included 14 males and 3 females. Fourteen patients had type 2 diabetes mellitus, while three cases had type 1 diabetes mellitus. As for other comorbidities, seven patients had hypertension, eight patients had nephropathy, and one patient had hypothyroidism. Seven eyes had TRD involving macula, three had TRD threatening macula, one had secondary RRD, and eight eyes had nonresolving vitreous hemorrhage along with FVP at posterior pole. A total of 13 eyes had vitreous hemorrhage, two eyes had VPT, and one eye had VMT with macular hole following PRP. Nuclear sclerosis more than Grade II was seen in ten eyes and thus phacoemulsification with PCIOL implantation was combined with vitrectomy in these cases. Four eyes were pseudophakic and five eyes had clear lens. There was no lens touch in any case and no cataract formation was noted in 3-month follow-up in any of the four cases.

During surgery, no difficulty was faced during core or periphery vitrectomy in any case. Segmentation and delamination was required in all cases. No additional instrument (scissors) was required in any of the surgeries for the dissection of preretinal FVP. One patient had subretinal band (SRB), which was dealt with retinotomy and removal with the help of end-grasping forceps. Inadvertent iatrogenic breaks formed in three eyes. These breaks were formed close to arcades when attempting lamination between FVP and retina. After adequately releasing traction and surrounding endolaser, both these cases were left under SF6 gas tamponade. ILM peeling was done in 12 eyes. The tamponade used was SF6 gas (25%) in 13 eyes and air in 6 eyes. Suture was not required in any of the case to seal the sclerotomies. Postoperative hypotony (IOP <6 mmHg) was not seen in any of the eyes. No intraoperative or postoperative serous or hemorrhagic choroidal detachment was seen in any of the cases.

Anatomical reattachment was seen in all the eyes on postoperative day one and at 3 months. Retinal detachment was not seen in any eye in 3-month follow-up period. The mean preoperative visual acuity was 2.5 on logMAR scale, which improved to 2.2 at 1 week, 1.2 at 1 month, and 1.01 at 3 months (P = 0.0003). There was no improvement in vision in three patients, which attributed to optic atrophy in one and macular ischemia in two cases. The mean IOP was 17.4 mm of Hg preoperatively, 14.9 mm of Hg at 1 week, 19.47 mm of Hg at 1 month, and 18.31 mm of Hg at 3 months. There was no significant difference in IOP between preoperative and at 3-month follow-up (P = 0.15). Five cases had increased IOP (>21 mmHg) on follow-up and required topical antiglaucoma medication for the management of the same. Among these five cases, three received tamponade with SF6 and two with air. IOP was controlled with topical brimonidine only in four patients, while one patient required a combined therapy of timolol and brimonidine.

Intraoperative bleeding was seen in few cases, but was in smaller amount and well controlled with increase in IOP. No case had vitreous bleed on postoperative day one. Patients with VMT with macular hole had bleed in the operated eye at 1-week follow-up, which resolved by 1 month and vision had improved from 1/60 preoperative to 6/60 at 3 months. One case had rebleed in vitreous cavity on the 25th day postoperatively, which resolved on its own by 3 months. However, there was no improvement in vision because of macular ischemia. None of the cases developed endophthalmitis on follow-up.

The traction could be removed in all the eyes without the need of any additional instrumentation such as chandelier or intravitreal scissors [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e, [Figure 1]f, [Figure 1]g, [Figure 1]h. No difficulty was encountered even in removing SRB in eye with secondary RRD [Figure 2]a, [Figure 2]b, [Figure 2]c. It is often assumed that removal of thick FVP and especially those mixed with thick coagulated blood might be difficult with 27G cutters. However, even thick membranes could be removed using 27G cutters [Figure 3]a, [Figure 3]b, [Figure 3]c.
Figure 1: (a) Large FVP at posterior pole with localized TRD with VPT. (b-g) Insertion of vitrectomy cutter tip between retina and FVP and segmentation. (h) Complete removal of traction and two iatrogenic breaks. FVP: Fibrovascular proliferation, TRD: Tractional retinal detachment, VPT: Vitreopapillary traction

Click here to view
Figure 2: A 57-year-old male presented with secondary rhegmatogenous retinal detachment and SRB (a). Diathermy of retina over the SRB (b). Grasping of SRB with twenty-seven-gauge end grasping forceps and its removal (c). SRB: Subretinal band

Click here to view
Figure 3: A 27-year-old male with type 1 diabetes presented with vitreous hemorrhage with FVP with TRD (a). Thick FVP nasal to disc with its subsequent cutting and complete removal in (b and c). FVP: Fibrovascular proliferation, TRD: Tractional retinal detachment

Click here to view

   Discussion Top

Wound leakage, high flexibility, and low illumination and flow rates limited the use of 27G vitrectomy to simple procedures in early days of its commencement. However, with refinement of insertion technique and availability of stiffer and wider range of compatible instruments, these concerns have been largely addressed and hence it is more widely used nowadays. There are multiple theoretical advantages of using 27G vitrectomy. Because of smaller incision diameter, a 1-step incision is sufficient in place of angled incision that is used commonly for 25/23G vitrectomy. Smaller incision also allows for a neater wound construction, which results in faster healing and minimal chance of leak or vitreous prolapse and endophthalmitis.[8],[9] Delayed wound healing and risk of infection is known to be more frequent in diabetics; thus, smaller incisions offer more safety.

Prevention of postoperative hypotony is crucial in vitrectomy for PDR as it may increase the chances of vitreous hemorrhage in post-operative period.

Early postoperative bleed is relatively common after vitrectomy for PDR and has been reported in up to 30% of the cases.[8] In our study, no patient developed hypotony and two patients (10.5%) had rebleed which resolved on its own. This is a big advantage of 27G vitrectomy over larger gauge MIVS.

During vitrectomy for PDR, it is imperative to remove all the traction on retina. Classically described techniques for the separation of densely adhered membranes and FVP from underlying retina include en bloc resection, segmentation, and delamination in varying permutations and combinations.[9] While sometimes en bloc resection is possible, in most cases, these membranes are densely vascularized with strong adhesions to underlying retina. Delamination involves horizontal cutting scissors to severe adhesions between the membranes and retina. A bimanual approach makes the delamination easier. Segmentation is performed where delamination is not possible due to nonvisibility of plain of separation, extremely dense adhesions, or underlying mobile retina (as in retinal detachment). During delamination, narrow gauge allows for easier insertion of the tip in plane of separation and membranes can be cut when keeping the port upward. During segmentation, the finer gauge allows it to be introduced even in very close adhesions.

Naruse et al. compared 25 versus 27G vitrectomy in 185 eyes with PDR and concluded that 27G vitrectomy was safe with similar postoperative results albeit with higher operative time.[5] Shahzadi et al. also showed that 27G vitrectomy was useful in diabetic vitreous hemorrhage.[10] However, these studies did not evaluate the cases on the basis of anatomical status of retina and did not mention how many of their cases had TRD, secondary RRD, thick FVP, and VPT. We retrospectively evaluated complex diabetic vitrectomy cases only and were able to tackle all these complex situations in a satisfactory way.

There are several limitations of our study. Our study was a retrospective study with a relatively small study population. Lack of control group resulted in absence of comparative results. However, our study highlights the potential intraoperative advantages of 27G vitrectomy over previously published studies.

   Conclusion Top

We report utility of 27G vitrectomy for performing complex diabetic vitrectomies with encouraging results. Due to smaller size of 27G cutter, it offers advantages in dissection of tightly adherent FVP and is associated with lower incidence of early postoperative hemorrhage.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Machemer R, Buettner H, Norton EW, Parel JM. Vitrectomy: A pars plana approach. Trans Am Acad Ophthalmol Otolaryngol 1971;75:813-20.  Back to cited text no. 1
Fujii GY, De Juan E Jr., Humayun MS, Pieramici DJ, Chang TS, Awh C, et al. A new 25-gauge instrument system for transconjunctival sutureless vitrectomy surgery. Ophthalmology 2002;109:1807-12.  Back to cited text no. 2
Eckardt C. Transconjunctival sutureless 23-gauge vitrectomy. Retina 2005;25:208-11.  Back to cited text no. 3
Oshima Y, Wakabayashi T, Sato T, Ohji M, Tano Y. A 27-gauge instrument system for transconjunctival sutureless microincision vitrectomy surgery. Ophthalmology 2010;117:93- 102.e2.  Back to cited text no. 4
Naruse Z, Shimada H, Mori R. Surgical outcomes of 27-gauge and 25-gauge vitrectomy day surgery for proliferative diabetic retinopathy. Int Ophthalmol 2019;39:1973-80.  Back to cited text no. 5
Zhang ML, Hirunyachote P, Jampel H. Combined surgery versus cataract surgery alone for eyes with cataract and glaucoma. Cochrane Database Syst Rev 2015;7:CD008671.  Back to cited text no. 6
Zhang Z, Wei Y, Jiang X, Zhang S. Surgical outcomes of 27-gauge pars plana vitrectomy with short-term postoperative tamponade of perfluorocarbon liquid for repair of giant retinal tears. Int Ophthalmol 2018;38:1505-13.  Back to cited text no. 7
Sato T, Morita S, Bando H, Sato S, Ikeda T, Emi K. Early vitreous hemorrhage after vitrectomy with preoperative intravitreal bevacizumab for proliferative diabetic retinopathy. Middle East Afr J Ophthalmol 2013;20:51-5.  Back to cited text no. 8
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Sharma T, Fong A, Lai TY, Lee V, Das S, Lam D. Surgical treatment for diabetic vitreoretinal diseases: A review. Clin Exp Ophthalmol 2016;44:340-54.  Back to cited text no. 9
Shahzadi B, Rizwi SF, Qureshi FM, Latif K, Mahmood SA. Outcomes of transconjunctival sutureless 27-gauge micro-incision vitrectomy surgery in diabetic vitreous haemorrhage. Pak J Med Sci 2017;33:86-9.  Back to cited text no. 10


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