This study included 27 eyes from 21 patients who underwent the combined surgical procedure and followed for at least 9 months. Mean age was 69.1±8.09 (range: 53- 85) years old. A total of 16 females (59.2%) and 11 males (40.7%), 10 (37%) right eyes and 17 (62.9%) left eyes were analysed.
All eyes with POAG were classified into 3 groups according to Glaucoma Grading Scale (HODAPP): 10 (37%) eyes were mild, 10 (37%) eyes moderate, and 7 (25.9%) eyes advanced. All 3 categories had a reduction in IOP at 9 months follow-up, but multiple comparisons with Nemenyi test after Friedman test showed a statistically significant improvement from the third month (p=0,010) in the mild glaucoma group, from the nine month for the moderate glaucoma group (p=0.031) and without statistically significant improvement in the advanced glaucoma group in any follow-up time, this can be attributed for the smaller sample size of this group. The IOP in the mild glaucoma group reduced 7.1 mmHg, in the moderate glaucoma group the reduction was 4.2 mmHg, and in the advanced glaucoma group the reduction was 6.6 mmHg at 9 months (Figure 3).
The mean preoperative IOP was 17.0 mmHg [± 3.7], postoperative IOP was 15.0 mmHg [± 5.3], 13.4 mmHg [± 4.1], 12.1 mmHg [±1.9], 11.6 mmHg [± 1.9.], 11.4 mmHg [± 1.8] at 1 week, 1, 3, 6, and 9 month respectively, (p<0.001). The mean IOP was reduced by 32.9% from baseline and the qualified success was 77.8% in the first month and 92.6% at 9 months follow-up (Figure 4).
The number of glaucoma medications preoperative was 1.9 [± 1.41], and postoperatively was 0.56 [± 1.05] at 9 months. The number of postoperative glaucoma medication was significantly reduced, 19 (70.3%) eyes were without glaucoma medication, 4 (14.8%) eyes with 1 medication, 4 (7.4%) eyes with 2 medications, 1 (3.7%) eye with 3 medications and 1 (3.7%) eye with 4 medications at 9 months (P<0.001). (Figure 5).
Visual acuity outcomes
Preoperative best corrected visual acuity (BCVA) showed and improvement from 0.4± 0.4 LogMAR to 0.2 ± 0.4 LogMAR at 9 months with no statistically significant differences.
The most common complications include: 1) hyphema (66,7%), found during the first week which resolved spontaneously in all cases at one month of follow up. 2) Intraoperative reflux bleeding was observed in all cases, but stopped by the time the surgery was completed. 3) corneal edema (7.4%). 4) Transient hypotony (3,7%). 5) Temporary IOP spike (6%). Complications such as iris injury, corneal descompensation, corneal injury, cyclodialysis, choroidal hemorrhage or endophthalmitis were not found.
This retrospective study of patients with uncontrolled POAG at different stages of the disease, showed a reduction of IOP, glaucoma medication with stable best corrected visual acuity at 9 months follow-up when a combined minimally invasive procedure consisting in phaco, ab-interno trabeculectomy and ECP is performed.
Cataract extraction as a stand alone procedure don’t provide a significant reduction of IOP in patients with primary open angle glaucoma1, therefore a combined treatment with a glaucoma surgery is almost always the choice for adequate control of the intraocular pressure. The available evidence suggests at most a modest reduction in IOP from cataract extraction around 1.5-3 mmHg9 possibly via decompression or mechanical stretch of the TM and Schlemm’s canal7. Siegel et al. demonstrated a statistically significant difference between the combined phaco-ECP group versus phaco alone10.
The combination of ECP with phacoemulsification and ab-interno trabeculectomy with phacoemulsification has been studied11. Kaplowitz K. Et all, described ECP used for POAG decreases IOP by 8%–47%, to a final average near 15 mm Hg12. Clement et al. combining phaco-ECP observed IOP reductions up to 69%, the mean reduction of 23.9% 12 months after treatment7,13.
A trial by Berke et al. compared 626 eyes treated with phacoemulsification/ECP and 81 eyes underwent phacoemulsification alone. The follow-up period ranged from 6 months to 5.5 years. In the phacoemulsification/ECP group, mean IOP decreased 3.4 mm Hg, from 19.1 to 15.7 mm Hg. In the control group, mean IOP increased 0.7 mm Hg, from 18.9 to 18.2 mm Hg. More significantly, the number of preoperative glaucoma medications decreased from a mean of 1.53 to 0.65 at the end of the follow-up period in the phacoemulsification/ECP group. There was no visual loss or significant adverse events postoperatively6. In our study the preoperative best corrected visual acuity (BCVA) showed and improvement from preoperative value of 0.4[± 0.4] LogMAR to 0.2 [± 0.4] LogMAR at 9 months (p=> 0.001 ).
In our combined study, the mean IOP was reduced 32.9% from baseline and the qualified success was 92.6% at 9 months. Morales et al., with Phaco/ECP reported the results obtained for IOP lowering to 15 mmHg and report an absolute success of 11.9% and a qualified success of 72.3%14. A retrospective Brazilian study on 247 patients, defined success based on IOP 21mm Hg, with 3 years of follow-up reported the corresponding rates were 55.7% for absolute success and 90.7% for qualified success15.
By the other side, The Kahook dual‑blade shows promise as a refined and economical device for the treatment of glaucoma3. Salinas et al. studied 53 eyes and the mean IOP decreased from 18.4±6.1 mm Hg at baseline to 13.9±3.5 mm Hg at 6 months follow-up (23.9% reduction, p<0.001); At 6 months, 63.5% achieved an IOP ≤14 mmHg and the mean number of glaucoma medications was reduced 1.2±1.3 compared to baseline (P<0.001), a reduction of 36.6% was found16. In our study with the combined procedures the mean IOP decreased from 17.0±3.7 mmHg at baseline to 11.6±1.9mmHg at 6 months (31.7% reduction, P<0.001), and an IOP of 11.4±1.8 mmHg at 9 months (32.9% reduction, P<0.001). The IOP was significantly reduced (P<0.001). The mean number of glaucoma medications was reduced 0.56±1.05 (29.5% reduction) from baseline to 9 months statistically significant (P<0.001).
SooHoo et al., in a preclinical study of human donor of corneo-scleral rims; the dual blade device was used to incise TM and then compared with trabectome. Dual‑blade showed more complete TM tissue removal and no significant damage to adjacent tissues3. Seibol et al., at the laboratory evaluation in a human eye perfusion model, demonstrated that trabectome treatment across 117.5 ± 12.6 degrees resulted in a decrease of IOP from 18.8 ± 1.7 mm Hg to 11.3 ± 1.0 mm Hg (P < .01) and with Dual-blade device treatment across 157.5 ± 26.3 degrees resulted in a decrease of IOP from 18.3 ± 3.0 mm Hg to 11.0 ± 2.2 mmHg (p < 0.01). The novel dual-blade device demonstrated a more complete removal of TM without residual TM leaflets or damage to surrounding tissues and significantly reduced IOP17.
Kaplowitz et al., showed that ab-interno trabeculectomy can be expected to lower the IOP by approximately 36% to a final mean IOP around 16 mmHg while decreasing the number of medications by less than one12. Fallano et al. used a combined treatment of phaco-trabectome with 18% reduction in IOP2. The cases of Trabectome combined with phacoemulsification showed a decrease in IOP from a preoperative mean of 20.0 ± 6.2 mmHg to a mean of 15.9 ± 3.3 mmHg at 12 months (n = 45), a decrease of 18%3. Francis et al. studied 304 patients treated with combined phaco-trabectome surgery, the mean IOP fell from 20.0±6.3 mmHg to 14.8±3.5 mmHg at 6 months and 15.5±2.9 mmHg at one year. The mean number of glaucoma medications was reduced from 2.65 ± 1.13 to 1.76 ± 1.25 at 6 months and 1.44 ± 1.29 at 1 year.1
Dang et al. combined trabectome and phaco-trabectome and divided the patients into 4 groups depending on glaucoma severity. The group with the higher glaucoma severity index (GI) has an IOP reduction of 2.34±0.19 mmHg more than the group with lower glaucoma severity index18. In our study, all subcategories showed a significant reduction in IOP 9 months after combined surgery. The mild group drop the IOP from 18.9 to 11.8mmHg, the moderate group from 15.3 to 11.1 mmHg, and advanced group from 17.4 to 10.8 mmHg.
The review and meta-analysis of Phaco/ECP from Kaplowitz et al., shows the most common complication is hyphema similar to the present study, the second most common complication was peripheral anterior synechiae in 24% of the patients. The most serious complication was hypotony 0.09% of all reposted cases12. SooHoo et al., with the use of Trabectome, all patients had transitory hyphema that resolved after 6.4 days.3 In our study, the most common complications include hyphema 18 (66.7%), intraoperative blending was observed in all cases, corneal edema (7.4%), transient hypotony (3,7%) and temporary IOP spike (6%) with no vision sequelae and no need for reoperations.
The main weakness of the study was the retrospective nature, low sample included and no control group.