335 Pak J Ophthalmol. 2020, Vol. 36 (4): 335-340 ORIGINAL ARTICLE Frequency of Post-Operative Hypotony in 23 Gauge and 25 Gauge Pars Plana Vitrectomy in Advanced Diabetic Eye Disease Hussain Ahmad Khaqan 1 , Usman Imtiaz 2 , Hasnain Muhammad Buksh 3 Hafiz Ateeq-ur-Rehman 4 , Raheela Naz 5 1-5 Department of Ophthalmology, Ameer-ud-Din Medical College PGMI, Lahore General Hospital, Lahore, Pakistan ABSTRACT Purpose: To compare the frequency of post-operative hypotony between 23G PPV and 25G PPV in advanced diabetic eye disease. Study Design: Quasi experimental study. Place and Duration of Study: Study was conducted at department of Ophthalmology, Lahore General Hospital, Lahore from 7 th April 2016 to 6 th October 2016. Methods: Total 100 cases of advanced diabetic eye disease with age ranging from 25 – 65 years and either gender were selected. Patients with nystagmus and claustrophobia, lamellar macular holes, epiretinal membrane and neovascular glaucoma were excluded. Patients were divided by lottery method into 2 groups. Data of the patient i.e. name, age, sex, patient’s registration number and address was recorded. Every patient had detailed preoperative work-up; including best corrected visual acuity by Snellen’s chart, intraocular pressure by applanation tonometer, indirect ophthalmoscopy and B-scan for retinal status. Group A underwent 23G PPV and group B underwent 25G PPV. Patients were followed after 24 hours of surgery to measure intraocular pressure to access hypotony. Results: Mean age of patients in group A was 50.16 ± 10.40 years and in group B was 50.26 ± 9.91 years. Out of 100 patients 57 (57.0%) were females and 43 (43.0%) were males, with female to male ratio of 1.1:1. Post-operative hypotony was seen in 24 (48.0%) patients with 23G PPV and 02 (4.0%) patients with 25G PPV (p-value = 0.0001). Conclusion: This study concluded that the frequency of post-operative hypotony in 23G pars plana vitrectomy was higher as compared to 25G pars plana vitrectomy in advanced diabetic eye disease. Key Words: Diabetic retinopathy, Pars Plana Vitrectomy, Hypotony. How to Cite this Article: Khaqan HA, Imtiaz U, Buksh HM, Rehman HA, Naz R. Comparison of Frequency of Post-Operative Hypotony in 23 Guage and 25 Guage Pars Plana Vitrectomy in Advanced Diabetic Eye Disease. Pak J Ophthalmol. 2020; 36 (4): 335-340. Doi: https://doi.org/10.36351/pjo.v36i4.1016 Correspondence: Hussain Ahmad Khaqan Ameer-ud-Din Medical College, Lahore General Hospital, Lahore – Pakistan Email: drkhaqan@hotmail.com Received: March 11, 2020 Accepted: July 23, 2020 INTRODUCTION Diabetes mellitus (DM) is of three types. Type I or insulin dependent DM or juvenile diabetes, type II or non-insulin dependent DM or adult-onset diabetes and gestational diabetes which occurs when pregnant women without a previous diagnosis of diabetes develop a high blood glucose level. 1 Incidence of mailto:drkhaqan@hotmail.com Post-Operative Hypotony in 23 Gauge and 25 Gauge Pars Plana Vitrectomy Pak J Ophthalmol. 2020, Vol. 36 (4): 335-340 336 diabetes mellitus is 10 – 14% worldwide. Diabetes mellitus type 2 (formerly non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes) is a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency while in diabetes mellitus type 1, due to destruction of islet cells in the pancreas, there is an absolute insulin deficiency. 2 Diabetes mellitus (DM) is one of the commonest world health problems affecting 92.4 million adults worldwide and its prevalence in Pakistan is 13.4%. 3 Among the large number of diabetic people, 35% develop some form of diabetic retinopathy and 10% progress to vision threatening stages and require treatment. 4 Prevalence of diabetic retinopathy in Pakistan was 28.76% in 2012. 3 Diabetic retinopathy contributes 10.2% to total blindness worldwide. Unfortunately, this blindness mostly affects the working age group of population. 4 Although the exact mechanism of diabetic retinopathy is unclear, but several theories have been postulated to explain the course of disease. Hyperglycemia alters blood vessel formation in retina of the eye, it can lead to blurring of vision and ultimately to blindness if left untreated. 5 Patients with type 2 diabetes mellitus, due to its delayed diagnosis, already have diabetic complications at the time of diagnosis. Duration of diabetes is directly proportional to the development of diabetic retinopathy. 6 Prevalence of diabetic retinopathy in patients with type 2 diabetes at the time of diagnosis varies from 5 – 35%. 7 Timely diagnosis of diabetic retinopathy and appropriate management can help delay the complications. Initial stages of diabetic retinopathy can be treated with good systemic control of blood sugar levels by showing compliance to their physicians and laser photocoagulation of retina. However, advanced diabetic eye disease requires surgery. Pars plana vitrectomy (PPV) remains the gold standard surgical treatment. 8 Improving the surgical technique aiming towards a better visual outcome developed trans-conjunctival suture-less vitrectomy. This also provides better patient’s comfort during and after surgery. 9 A study comparing 23G PPV and 25G PPV for posterior segment disease revealed that post-operative hypotony was 41.3% with 23G PPV and none with 25G PPV. Another study showed that eyes operated with 23G PPV present with intra-ocular pressure (IOP) less than 6 mm Hg (hypotony) more frequently when compared with eyes operated through 25G PPV (p = 0.034). This resulted in more frequent application of port sutures in eyes operated through 23G PPV (p = 0.014). 10 25G PPV may prove a good alternate to the traditionally used 23G PPV. Giving the patient an extra benefit in the form of better comfort and earlier visual rehabilitation. Smaller incision also allows better anatomical preservation of delicate ocular structures and lessens the risk of post-operative infections according to principles of minimum invasive surgery. 9 This study was conducted with the aim to compare post-operative hypotony in 23G and 25G PPV. Currently both approaches of surgery are in use and according to the results of this study, better surgical approach can be adopted to avoid post-operative hypotony. METHODS This Quasi experimental study was conducted at Department of Ophthalmology, Lahore General Hospital, Lahore from 7th April 2016 to 6th October 2016. Total of 100 patients were included in the study with 50 patients in each group. Non-probability, consecutive sampling technique was used. Patients from 25-65 years of age from both sexes, with diabetes for more than 5 years and diagnosed with advanced diabetic eye disease were included in the study. Patients with nystagmus and claustrophobia and pre- operative IOP of less than 6 mm Hg, patients who were unable to maintain supine posture, mentally handicapped patients, patients with neo-vascular glaucoma, epiretinal membrane and patients with lamellar macular holes were excluded from the study. Informed consent was obtained from all patients. Data of the patients including name, age, sex, patient’s registration number and address were recorded. Every patient had detailed preoperative work-up which included best corrected visual acuity by Snellen’s chart, intraocular pressure by applanation tonometer, indirect ophthalmoscopy and B-scan for retinal status. Patients were divided by lottery method into 2 groups. Group A underwent 23G PPV and group B underwent 25G PPV. Intraocular pressure was measured by applanation tonometry on first post-operative day. Data was recorded on a pre-designed proforma. 23G http://en.wikipedia.org/wiki/Metabolic_disorder http://en.wikipedia.org/wiki/Blood_glucose http://en.wikipedia.org/wiki/Insulin_resistance http://en.wikipedia.org/wiki/Insulin http://en.wikipedia.org/wiki/Diabetes_mellitus_type_1 http://en.wikipedia.org/wiki/Diabetes_mellitus_type_1 http://en.wikipedia.org/wiki/Diabetes_mellitus_type_1 http://en.wikipedia.org/wiki/Islets_of_Langerhans http://en.wikipedia.org/wiki/Pancreas http://en.wikipedia.org/wiki/Retina http://en.wikipedia.org/wiki/Blindness Hussain Ahmad Khaqan, et al 337 Pak J Ophthalmol. 2020, Vol. 36 (4): 335-340 and 25G PPV procedure are minimally invasive retinal surgeries to deal with retinal diseases through small trans-conjunctival scleral incisions at pars plana. These micro incisions facilitate the insertion of instruments e.g. vitrectomy cutter, endo-illuminator and fluid to maintain globe integrity and intraocular pressure. Patients were followed after 24 hours of surgery to measure intraocular pressure to access hypotony. SPSS version 12.0 was used for statistical analysis of the data. Results were shown as mean and standard deviation was used for quantitative variables i.e. age and post-operative intra-ocular pressure of patients. Frequency and percentage were calculated for qualitative variables like gender and hypotony (present/absent). Frequency of hypotony was compared in both groups by using chi square test with p-value ≤ 0.05 as significant. Effect modifiers like age, gender and duration of DM were controlled through stratifications. Post-stratification chi square was applied to see their effects on outcome and p value ≤ 0.05 was considered as significant. RESULTS In this study, the age ranged from 25 to 65 years with mean age of 50.21 ± 10.11 years. Mean age of patients in group A was 50.16 ± 10.40 years and in group B was 50.26 ± 9.91 Table 1: Age Distribution for Both Groups (n = 100). Age (Years) Group A (n = 50) Group B (n = 50) Total (n = 100) No. of Patients % age No. of Patients % age No. of Patients % age 25 – 40 11 22.0 10 20.0 21 21.0 41 – 55 18 36.0 20 40.0 38 38.0 56 – 65 21 42.0 20 40.0 41 41.0 Mean ± SD 50.16 ± 10.40 50.26 ± 9.91 50.21 ± 10.11 Table 2: Distribution of Patients According to Duration of DM (n = 100). Duration (Years) Group A (n = 50) Group B (n = 50) Total (n = 100) No. of Patients % age No. of Patients % age No. of Patients % age 6 – 10 21 42.0 23 46.0 44 44.0 > 10 29 58.0 27 54.0 56 56.0 Mean ± SD 8.24 ± 4.09 8.39 ± 4.18 8.32 ± 4.13 Table 3: Stratification of Post-operative Hypotony According to Age. Age of Patients (Years) Group A (n = 50) Group B (n = 50) P-value Hypotony Hypotony Yes No Yes No 25 – 40 04 (36.36%) 07 (63.64%) 00 (0.0%) 10 (100.0%) 0.034 41 – 55 09 (50.0%) 09 (50.0%) 01 (5.0%) 19 (95.0%) 0.002 56 – 65 11 (52.38%) 10 (47.62%) 01 (5.0%) 19 (95.0%) 0.001 Table 4: Stratification of Post-operative Hypotony According to Gender. Gender Group A (n = 50) Group B (n = 50) P-value Hypotony Hypotony Yes No Yes No Male 12 (57.14%) 09 (42.86%) 01 (4.55%) 21 (95.45%) 0.000 Female 12 (41.38%) 17 (58.62%) 01 (3.57%) 27 (96.43%) 0.001 Table 5: Stratification of Post-operative Hypotony According to Duration of DM. Duration Group A (n = 50) Group B (n = 50) P-value Hypotony Hypotony Yes No Yes No 6 – 10 years 10 (47.62%) 11 (52.38%) 00 (0.0%) 23 (100.0%) 0.000 > 10 years 14 (48.28%) 15 (51.72%) 02 (7.41%) 25 (92.59%) 0.001 Post-Operative Hypotony in 23 Gauge and 25 Gauge Pars Plana Vitrectomy Pak J Ophthalmol. 2020, Vol. 36 (4): 335-340 338 years. 41.0% patients were between 56 to 65 years of age. Out of 100 patients, 57 were females and 43 were males, with female to male ratio of 1.1:1. Mean duration of diabetes mellitus in group A was 8.24 ± 4.09 years and in group B was 8.39 ± 4.18 years. Most of the patients (56.0%) had >10 years of duration of diabetes mellitus. Mean intra-ocular pressure was 9.41 ± 3.12 mm Hg. Post-operative hypotony was seen in 24 (48.0%) patients with 23G PPV and 02 (4.0%) patients with 25G PPV (p-value = 0.0001). Stratification of post-operative hypotony with respect to age groups showed significant difference in post- operative hypotony in both groups. Similarly, statistically significant difference was found in post-operative hypotony in both genders between both groups. For details see tables 1 to 5. DISCUSSION Complicated vitreoretinal disease, such as advanced diabetic eye disease has been treated using 20-G or 23- G PPV. However, in 2002, Fujii described 25-G PPV, which has revolutionized the vitreoretinal surgeries. 11 The advantages include short duration of surgery, decreased inflammation, rapid visual recovery, comfortability, reduced rate of iatrogenic retinal breaks, preservation of limbal stem cells, and reduced corneal astigmatism. The indications for 25-G PPV are macular holes, idiopathic epiretinal membranes, refractory macular edema, and non-resolving vitreous hemorrhage. 12 The delicacy or limited variety of instrumentation for 25-G PPV has rendered its use limited for uncomplicated surgeries. 13,14,15 Data has shown comparable outcomes and complication rates between 25-G PPV and 20-G or 23-G systems for complicated retinal surgeries like diabetic Tractional retinal detachment. 16 A study comparing 23G PPV and 25G PPV for posterior segment disease revealed that post-operative hypotony was 41.3% with 23G PPV and none with 25G PPV. 17 Another study showed that eyes operated with 23G PPV presented with intra-ocular pressure (IOP) less than 6 mm Hg (hypotony) when compared with eyes operated through 25 G PPV (p = 0.034). The aim of small gauge vitrectomy or minimally invasive vitreous surgery (MIVS) is to minimize invasion with maximum success of the surgery. The much-criticized small gauge vitrectomy has now gained popularity. Thus, instruments used in vitreoretinal surgery are now available in 23-G and 25-G sizes. Initial success rate for 25-G vitrectomy has increased from 74% to 92.9% with gas as tamponade. 18 Literature shows approximately up to 25% rates of hypotony following suture-free vitrectomy. The severity can range from mild and transient cases, which resolve after conservative management, to severe cases which could lead to hypotonic maculopathy, optic choroidopathy and large choroidal mounds. The following factors can lead to wound leakage and can result in hypotony; redo surgery on a vitrectomized eye, multiple instrumentation, young age, widespread dissection of vitreous base and wound construction alteration. 19 The two-step procedure is superior to one-step technique in terms of lower rates of wound leakage. Technique of trocar insertion can influence the rate of hypotony. Direct insertion of cannulais associated with higher rates of wound leakage 20 . Oblique or oblique- parallel entry helps in scleral wound re-apposition, thus reducing wound leakage. Retraction of the conjunctiva while trocar entry may be beneficial. 21 While using one-step technique, wound leakage is minimal for extreme oblique trocar entry and relatively higher for oblique and direct cannula entry. No difference was observed in wound leakage following 23-G and 25-G vitrectomies. 22 This is further supported by imaging of wound healing by optical coherence tomography of the anterior segment. After a 25-G vitrectomy, scleral wounds assessed by optical coherence tomography were closed at 60.5% at one month follow up and 63.9% at three month follow up. After a 23-G vitrectomy, 57.4% of scleral wounds were seen closed at one month and 61.1% at three months postoperatively 23 . In a study by Bamonte et al, rate of hypotony after 25-G vitrectomy was 9.2%. 24 They also found that the rate of hypotony was higher in cases where fluid tamponade was used. On the whole, it was concluded that frequency of post-operative hypotony in 23 G PPV was higher compared to 25G PPV in advanced diabetic eye disease. CONCLUSION This study concluded that the frequency of post- operative hypotony in 23G Pars plana virectomy is higher when compared to 25G Pars plana virectomy in advanced diabetic eye disease. Hussain Ahmad Khaqan, et al 339 Pak J Ophthalmol. 2020, Vol. 36 (4): 335-340 REFERENCES 1. Shoback, Gardner DG, Dolores. Greenspan's basic & clinical endocrinology. 9th ed. New York: McGraw- Hill Medical, 2011; Chap 17. 2. Vijan S. Type 2 diabetes. Ann Intl Med. 2010; 152 (5): 31–15. 3. Khanzada MA, Siyal NA, Mirza SA, Memon A, El- Muttaqi A, Mirza AA. Frequency and types of diabetic maculopathy in type II diabetes. Pak J Surg. 2013; 29 (2): 139-142. 4. Ludwig J, Sanbonmatsu L, Gennetian L, Adam E, Duncan GJ, Katz LF, et al. Neighborhoods, obesity, and diabetes--a randomized social experiment. N Engl J Med. 2011; 365 (16): 1509-1519. 5. Yng W, Lu J, Weng J, Jia W, Xio J. Prevalence of diabetes among men and women in China. N Engl J Med. 2010; 362 (12): 1092-1101. 6. Zafar J, Bhatti F, Akhtar N, Rasheed U, Humayun S, Waheed A, et al. Prevalence and risk factors of diabetes mellitus in a selected urban population of a city in Punjab. J Pak Med Asso. 2011; 61: 40-47. 7. Yau JW, Rogers SL, Kawasaki R, Lamoureux EL, Kowalski JW, Bek T, et al. Global prevalence and major risk factors of diabetic retinopathy. Dia Care, 2012: 556-564. 8. Memon WU, Jadoon Z, Qidwai U, Naz S, Dawar S, Hasan T. Prevalence of diabetic retinopathy in patients of age group 30 years and above attending multicenter diabetic clinic in Karachi. P J Ophthalmol. 2012; 28 (2): 99-104. 9. Bxter SL, Wormald RP, Musa JM, Patel D. Blindness registers as epidemiological tools for public health planning: a case study in Belize. Epidemiol Res Int. 2014; 2014: 1-8. 10. Ockrim Z, Yorston D. Managing diabetic retinopathy. BMJ. 2010; 341: c5400. 11. 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 (10): 1807-1812 12. Khanduja S, Kakkar A, Majumdar S, Vohra R, Garg S. Small gauge vitrectomy: Recent update. Oman J Ophthalmol. 2013 Jan; 6 (1): 3-11. 13. Rizzo S, Genovesi-Ebert F, Vento A, Miniaci S, Cresti F, Palla M. Modified incision in 25-gauge vitrectomy in the creation of a tunneled airtight sclerotomy: an ultrabiomicroscopic study. Graefes Arch Clin Exp Ophthalmol. 2007 Sep; 245 (9): 1281-1288. 14. Hubschman JP, Gupta A, Bourla DH, Culjat M, Yu F, Schwartz SD. 20-, 23-, and 25-gauge vitreous cutters: performance and characteristics evaluation. Retina. 2008 Feb; 28 (2): 249-257. 15. Ahmad M, El-Asrar A. Advances in the treatment of diabetic retinopathy. Saudi J Ophthalmol. 2011; 25 (2): 113-122. 16. Newman DK. Surgical management of late complications of proliferative diabetic retinopathy. Eye, 2010; 24: 441-449. 17. Kayani H, Ahmad A, Jahangir K, Rehman H, Chauhan K. Comparison between 23-guage and 25- guage pars plana vitrectomy for posterior segment disease. Pak J Ophthalmol. 2013; 29: 42-45. 18. Guther G, Magbill H, Steel HW. 23-guage versus 25- guage vitrectomy for proliferative diabetic retinopathy: a comparison of surgical outcomes. Ophthalmologica. 2015; 233: 104-111. 19. Schrader WF. The options to minimize the surgical trauma to treat ocular diabetic complications. EPMA J. 2010; 1: 82-87. 20. Cooper MA, Hutfles S, Segav DL, Ibrahim A, Lyu H, Makary MA. Hospital level underutilization of minimally invasive surgery in United States. BJM. 2014; 349: g4198. 21. Teixeira A, Allemann N, Yamada AC, Uno F, Maia A, Bonomo PP. Ultrasound biomicroscopy in recently postoperative 23-gauge transconjunctival vitrectomy sutureless self-sealing sclerotomy. Retina, 2009; 29: 1305–1309. 22. López-Guajardo L, Vleming-Pinilla E, Pareja- Esteban J, Teus-Guezala MA. Ultrasound biomicroscopy study of direct and oblique 25-gauge vitrectomy sclerotomies. Am J Ophthalmol. 2007; 143: 881–883. 23. Singh RP, Bando H, Brasil OF, Williams DR, Kaiser PK. Evaluation of wound closure using different incision techniques with 23-gauge and 25-gauge microincision vitrectomy systems. Retina, 2008; 28: 242–248. 24. Bamonte G, Mura M, Stevie Tan H. Hypotony after 25-Gauge Vitrectomy. Am J Ophthalmol. 2011; 151: 156–160. Authors’ Designation and Contribution Hussain Ahmad Khaqan; Associate Professor: Concepts, Designs, Literature Research, Data Acquisition, Data Analysis, Manuscript Preparation, Manuscript Editing, Manuscript Review. Usman Imtiaz; Post Graduate Trainee: Literature Research, Data Acquisition, Data Analysis, Statistical Analysis, Manuscript Preparation, Manuscript Editing, Manuscript Review. Hasnain Muhammad Buksh; Medical Officer: Literature Research, Data Acquisition, Data Analysis, Statistical Analysis, Manuscript Preparation, Manuscript Editing, Manuscript Review. Post-Operative Hypotony in 23 Gauge and 25 Gauge Pars Plana Vitrectomy Pak J Ophthalmol. 2020, Vol. 36 (4): 335-340 340 Hafiz Ateeq-ur-Rehman; Post Graduate Trainee: Data Acquisition, Data Analysis, Statistical Analysis. Raheela Naz; Post Graduate Trainee: Data Acquisition, Data Analysis, Statistical Analysis. .…  ….