AIOS – Sujatha Savithri Rao Award
Dr. Gupta Roshmi,G08406, Dr. Parvathi T Hari, Dr. Anjali Kiran, Dr.Bhawna Piplani
Abstract
Aim:
To study patients with implant exposure vswithout,to analyze risk factors for exposure.
Methods
Case control study; Group A- implant exposures after evisceration,Group B – without exposure, matched followup.
Results
Group A – 32 eyes of implant exposure, median 18 months; Group B followup median 36 months. Chi Squared test, Odds Ratio(OR) calculated; panophthalmitis-OR 1.3, p=0.6; phthisical eye – OR 1.4, p=0.43; prior surgeries- OR 1.55,p=0.33. Group A had 62.5% porous implants, Group B 55.7%,- OR 1.3, p=0.5. Mean implant size in Group A 19.06 mm, Group B 18.78 mm- no statistical differenceMultiple logistic regression analysis showed no significant factor. Surgeon factor was not analysed since there were multiple surgeons.
Conclusion
Implant material, panophthalmitis, phthisical scleral shell, prior surgery showed higher trend of exposure, but none conclusive. Larger size of implant was not significant. More weightage should be given to meticulous surgery and close followup.
Materials and Methods:
A retrospective review of records of patients who under went evisceration and implant between 2009 Jan -2014 April. Informed consent was provided by all patients who underwent surgery.
Patient details like age, gender, the indication for surgery, surgical technique, implant used and post operative complications were noted from the records. Patients with exposure of implant and patients with a minimum follow up of two years were included as controls. The surgeries were performed by different surgeons, who all followed the same technique; however, the surgeons varied in level of skill and experience; the surgeon factor could not be analysed due to the large number of surgeons including residents and surgeons in training.
In patients with exposure of implant, the duration since the surgery,presence of symptoms like pain, bleeding, discharge on presentation were noted.
Statistical analysis was performed using Medcalc. The odds ratio and chi square test was calculated and multiple logistic regression analyzed to evaluate the effect of various factors like type of implant, age of patient, gender, indication for surgery.
Results:
A total of 93 eyes of 93 patients were included in the study. Group A had 32 eyes with mean follow up of 18 months. The mean age of the patients in this group A was 41.56years( 16-80 years).
Group B had 61 eyes, with mean follow up of 36 months.Mean age was 32.18 years (3-70 years).
In group A- average duration following surgery to detection of implant exposure 20 months.
Among the 32 patients, infection was present in 6, 20 eyes were phthsical and 12 had undergone prior surgeries. Non porous implant (silicone12, PMMA 1) was used in 13 patients, Porous implants used in 19(biopore11, hydroxyapatite 2, bioceramic 6). Average implant size used was 19.06mm(18 -20 size).
Among the patients who presented with exposure, nine presented with pain, eight of them had discharge and five patients presented with bleeding from the socket.
Group B patients had an average follow up of 37 months (12-65 months). Among the 61 patients infection was present in 9; Phthisis bulbi in 33 and 17 had undergone prior surgery.
Non porous implant was used in 27 patients and the rest was porous implant. Average diameter of implant used 18.7 mm(16-22 size).Group A had 62.5% porous implants and group B had 55.7%.
The odds ratio was calculated, was found that type of implant, size, presence of previous infection, surgeries were not significant.
| Odds Ratio | P value | |
| Infection | 1.3 | 0.6 |
| Phthisical eye | 1.4 | 0.43 |
| Multiple prior surgeries | 1.55 | 0.33 |
| Porous implant | 1.3 | 0.5 |
Discussion:
There have been numerous studies comparing different implants used in evisceration and its outcome. Implant exposure rates in the existing literature varies from 0% to 21% 1.
Porous implants are preferred by many surgeons as the fibrovascular in growth into the implant reduces the rate of exposure, improves prosthesis motility and cosmesis. Similarly our surgeons also preferred porous implant over non porous .We found that the type or the size of the implant were not important factors that lead to development of exposure. Though the average size of implant in group A was higher, it was not statistically significant.
The use of implant in infected eyes has been extensively studied by various groups. In a recent study by ,Dresner et al 2 one porous polyethylene exposure was reported in a series of 11 patients with Pseudomonas aeruginosa endophthalmitis. Another study by Tawfik et al 3 reported no complications with the use of porous implants in endophthalmitis. That study shows the possibility of successful primary porous orbital implant placement in patients with endophthalmitis. Our study also showed similar results with no significant complications in cases where porous or non porous implant was placed in eyes with endophthalmitis. It being a retrospective study we could not assess the extent of infection, as it may probably play a role in development of exposure due to presence scleral melt.
In this series most common indication for surgery was phthisis bulbi. Placing a large implant in a phthisical eye to correct the volume loss, may lead to inadequate sclera cover over the implant and cause exposure. Though we found no significant difference in both the groups, the axial length of the phthisical eye should be considered while determining the size of implant. Another important factor is the surgical technique used. As there were multiple surgeons , we could not analyze the surgical techniques.
Most patients who had exposure were detected only during routine evaluation. Some of the patients had symptoms like bleeding, discharge and pain.
The draw backs of this study include, the surgeon factor not taken into account, as variable technique has been found to have an impact on the outcome. Post operative factors like inflammation/ infection that could have led to the exposure could not be studied.
Conclusion:
Implant size or types of implant used are not the only factors important to avoid exposure or extrusion of implant. Meticulous surgery is the key to avoid implant exposure.
References:
- Alwitry A, West S, King J, et al. Long-term follow-up of porous polyethylene spherical implants after enucleation and evisceration. OphthalPlastReconstrSurg 2007;23:11-5.
- Dresner SC, Karesh JW. Primary implant placement with evisceration in patients with endophthalmitis. Ophthalmology 2000;107:1661–4.
- Tawfik HA, Budin H. Evisceration with primary implant placement in patients with endophthalmitis.2007;