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- Materials and methods
Purpose: To evaluate the anatomical success rate of scleral buckling surgery in the treatment of rhegmatogenous retinal detachment and to evaluate the differences in outcome between patients suffering macula-off retinal detachment and those without a macular involvement.
Methods: As a retrospective interventional case series, Munster Study on Therapy Achievements in Retinal Detachment (MUSTARD) is one of the largest ever established of retinal detachment patients and their outcome after buckling surgery, with 4325 patients who underwent surgery between 1980 and 2001. In 53.94% (n = 2134) of 3956 patients with nontraumatic retinal detachment, the macula was involved. The main outcome measure was the achievement of dry anatomical attachment of the retina.
Results: The success rate in patients with macula-off retinal detachment is 80.46% and thus 7.78% lower (p < 0.01) than that in those patients with their macula intact whose success rate amounted to 88.24%. The overall success rate of all 4325 MUSTARD patients was 83.98%.
Conclusions: Scleral buckling is an established and mostly successful method for the treatment of retinal detachment. As our case series has demonstrated, even eyes with macula-off can be treated successfully by this procedure, thereby avoiding the complications of primary vitrectomy.
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- Materials and methods
Rhegmatogenous retinal detachment is a major sight-threatening disease of the posterior segment of the eye that can be cured by surgery alone. Risk factors for retinal detachment include, among others, age, aphakia, myopia, pseudophakia, recent eye surgery and trauma. With current surgical techniques, 90% or more of all retinal detachments can be successfully reattached with one or more operations (Wilkinson 2006), (Ho et al. 2002), (Afrashi et al. 2005). The two current – and, in some surgeons’ opinion, competing – methods of treatment are scleral buckling with the intent to facilitate a reattachment and primary pars plana vitrectomy (PPV). In some surgical centres, a combination of the two procedures might be employed. The anatomical success rate is dependent on preoperative pathology; anatomical success rates after buckling surgery or PPV may be as high as 96% (La Heij et al. 2000).
One aspect of preoperative pathology that has a major impact on the anatomical and functional outcome of surgery is whether the macula is still attached or is part of the detachment (Doyle et al. 2007), (Oshima et al. 2000). After a macula-off retinal detachment, improvement of central vision often remains compromised owing to the permanent functional damage the macula has suffered while detached. Even in cases where surgery has been successful, a reattached retina with macula-off rarely regains normal sensitivity or acuity (Diederen et al. 2007). Several studies have concluded that the outcome of the surgical repair of macula-off retinal detachment is time dependent. Better visual acuity was achieved in a group that was treated <10 days after detachment compared to a group treated after longer periods following the development of macula-off retinal detachment (Hassan et al. 2002). A Dutch study recently demonstrated that starting 6 days following the development of the retinal detachment, the visual outcome can be expected to become progressively worse (Diederen et al. 2007).
By evaluating one of the largest case series of retinal detachments, with both macula-off and macula-on, we aim to shed new light on the incidence of macula-off as well as on the anatomical success rates of buckling surgery relative to the overall outcome in the conventional treatment (‘conventional’ as opposed to primary vitrectomy) of rhegmatogenous retinal detachment. Our study is purely retrospective; because further management of the patients took place in the offices of other ophthalmologists, our data does not include details of the postoperative history of the patients after dismissal from our hospital. Therefore, we cannot provide any information on the functional developments over the course of the next months (or years) following buckling surgery. Thus, the ‘dry’ anatomical reattachment is the end-point of our analysis.
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- Materials and methods
In 53.94% (n = 2134) of 3956 patients with nontraumatic retinal detachment, the macula was involved. The 80.46% success rate in patients with macula-off retinal detachment is 7.78% lower (p < 0.01) than that in patients with their macula intact whose success rate amounted to 88.24%. Of our 4325 patients, 3632 were classified as an anatomical success, which amounts to 83.98%. Success rate in all male patients was 84.99%; in all female patients enrolled in MUSTARD, the success rate was 83.75%.
In general, patients with macula-off (nontraumatic) suffered a much more dramatic loss in visual acuity than other patients with retinal detachment, as Fig. 1 demonstrates. In almost 10% of patients with macula-off, visual function was reduced to light perception; almost 30% could only count fingers or see hand motions.
The majority of patients with macula-off suffered an extensive retinal detachment. A total of 12.37% of macula-off patients, for instance, had a detachment extending over 10–12 clock hours, which was the case in only 0.66% of patients with their macula still in place. A detachment of 6 clock hours or more was diagnosed in 53.32% of patients with macula-off and in 10.11% of patients without macular detachment.
Our success rate in macula-off patients was highest in the 21- to 30-year-old age group with 87.79%, then in patients aged 51–69 (83.69%), followed by those aged 61–70 (83.33%). The success rates were lowest in children up to 10 years with a detached macula (76.92%), in age group 71–80 (74.07%) and 81–90 (70.48%). By comparison, the success rates in all MUSTARD patients were more evenly distributed with the lowest in children (84.62%) and the highest (besides a statistical anomaly in the small group of patients in their tenth decade of life) in the age groups 41–50 (90.31%) and 11–20 (93.75%).
Patients with trauma
Of our 369 patients with trauma, 166 (44.99%) had macula-off, while the remaining 203 patients had macula-on. A total of 122 of those 166 macula-off patients were operated upon successfully. This success rate of 73.49% is strong contrast to the success rate of 91.63% among trauma patients with their macula in place.
Patients with macula-off experienced different outcomes depending on their respective lens status. Of 469 patients with aphakia treated between 1980 and 2001 without trauma as a cause of the retinal detachment, 62.47% suffered a macular detachment. Once again, patients with macula-off had distinctly worse results than those with an unaffected macula (p < 0.05). In 79.18% of aphakic macula-off patients, the outcome was considered a success; in aphakic patients with attached macula, the success rate was 86.36%.
These differences were less significant in patients with pseudophakia. Of 333 patients with pseudophakia, the macula was affected in 61.56%. Of these 205 patients, 81.95% underwent successful surgery. In 128 patients without macular involvement, the operation was deemed a success in 84.38% (p < 0.05).
Among pseudophakic macula-off patients, the success rates were highest in age groups 61–70 (87.27%) and 41–50 (85.00%). The lowest success rates of pseudophakic macula-off patients were registered in the oldest patients, those aged 81–90 with 75.86%.
At the time of their examination at Munster’s University Eye Hospital, 3151 nontrauma patients with retinal detachment still had their natural lens in place. A total of 51.89% of these patients suffered a macular detachment and the macula was intact in 48.05%. The success rate of 88.77% in patients with an intact macula was 8.28% higher than the 80.49% in those with macula-off (p < 0.01).
Almost exactly two-thirds (66.33%) of all our patients with retinal detachment suffered the typical symptoms of this sight-threatening disease, while the remaining 1333 patients did not have any clinical complaints: In the former group, the success rate of 85.25% was higher than in the asymptomatic patients with an 81.62% success rate. Of the 2623 patients describing symptoms, 1467 (55.93%) suffered a detachment with macula-off. Among those 1333 patients who appeared to be asymptomatic, 667 (50.04%) had their macula detached. This is certainly a surprising result of our analysis: Almost half of these individuals had the most important part of their retina detached without experiencing floaters or flashes or other symptoms associated with retinal detachment.
We found not only a statistically significant difference (p = 0.023) in success rates between symptomatic (89.53%) and asymptomatic (85.99%) patients but also in patients with an affected macula. Patients with macula-off and typical symptoms could be treated successfully 81.87% of the time and asymptomatic patients with macula-off 77.36% (p = 0.014) of the time. The reason for the higher success rate in the former group might be the fact that patients with symptoms tend to see an ophthalmologist sooner rather than later.
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- Materials and methods
The involvement of the macula proved to be correlated with anatomical success, in patients with trauma as well as in nontraumatic ones. The rate of anatomical reattachment was higher in patients with macula-on than in those with macula-off.
There was insignificant (p < 0.01) difference in success rates between patients with their macula still attached (88.24%) and patients with macula-off (80.46%). The lower success rate in macula-off retinal detachment was irrespective of the patients’ lens status, and it did not make any difference if the patient was phakic, aphakic or pseudophakic or if the retinal and macular detachment was owing to trauma. In general, our overall success rates (with all 4325 MUSTARD patients) were in general astonishingly consistent through most age groups, from infants up to age 70. Only in patients beyond age 70, did a significant drop in anatomical reattachment occur.
There was no difference in outcome in the general study population between men (success rate 83.44%) and women (success rate 83.67%) with posttraumatic retinal detachment. Our results in macula-off patients, who tend to have a below-average prognosis compared to patients with retinal detachments not involving the macula, seem to support our experience that scleral buckling is a generally highly successful mode of therapy in the management of retinal detachment.
Other authors have reported a reattachment rate of 86% with primary vitrectomy in eyes with macula-off retinal detachment; major complications with this approach were clinical or angiographic evidence of cystoid macular oedema (17%) and macular pucker (16%) (Campo et al. 1999). Our findings are also comparable to those achieved recently by an Austrian study group who used a microsurgical approach to retinal buckling surgery and reported a success rate of 85% (Falkner-Radler & Binder 2008).
Macula-off is widely regarded as one of several factors leading to a worse anatomical and functional outcome, together with the extension of the detachment, a history of earlier detachments and advanced age (Pastor et al. 2008). Morphological changes that influence the outcome are, according to a recent study using spectral-domain optical coherence tomography, the dropout of the photoreceptor inner and outer layer segment in the fovea (Nakanishi et al. 2009). The most recently described persistence of subretinal fluid in young macula-off patients treated with buckling surgery may contribute to a limited visual acuity long after an anatomical successful outcome (Abouzeid et al. 2009). Besides the time interval between detachment and surgical reattachment, another factor that seems to play a major role in the functional outcome of buckling surgery in cases of macula-off was the height of the macular detachment. It was shown recently that a lower height of macular detachment correlates with better visual recovery after treatment of macula-off retinal detachment (Ross et al. 2005). Another recent study has established the height of macular detachment as a statistical predictor of postoperative visual acuity. Supposedly, the shallower the macular detachment is, the greater the likelihood is of a good visual outcome is supposed to be (Mowatt et al. 2009).
The authors hope to contribute to this aspect of retinal detachment surgery after further evaluation of the data from MUSTARD.
One of MUSTARD’s purposes is to contribute to the ongoing debate about what the best surgical method to treat retinal detachment is. Our purpose for this analysis was exclusively to determine the success rates of ‘pure’ buckling surgery without any additional interventions. Therefore, we excluded patients who underwent other or additional procedures such as air or gas injections. While we cannot rule out any bias in patient selection completely, we consider it unlikely that so-called less severe cases have been treated with buckling surgery, while the more severe retinal detachments might have received a different, supposedly more ‘advanced’ therapy – the relatively large percentage of macula-off patients among all individuals enrolled in MUSTARD gives, in our opinion, proof that the extent of the detachment did not discourage the surgeons to resort to buckling surgery. Scleral buckling is widely considered the more ‘conventional’ approach. Scleral buckling has evolved since the 1950s following the concept of Jules Gonin that pointed to the closure of the retinal break as the logical way to heal retinal detachment. Major complications after buckling surgery can include refractive changes, most importantly myopia induced by a cerclage. Strabismus can occur after a buckling procedure as well as the extrusion or intrusion of the buckling element.
The second surgical procedure is PPV, which allows direct relief of vitreous traction and requires an intraocular tamponade after the procedure. Major complications are cataract development and rises in intraocular pressure (IOP). Intraoperative damage and postoperative increase in nuclear cataract were established in more than one-third of the patients (SPR Study-Group 2003).
Recent studies on the anatomical and functional outcome of surgery for the treatment of retinal detachment paint a mostly positive picture. A Medline search, for instance, comprising 1462 primary retinal detachments treated with buckling surgery without drainage, revealed a success rate of 91% and a relatively low rate of further surgery (10.7% of patients had one further procedure, 0.7% had two procedures) (Barrie et al. 2003). A comparison of more than 20 reports of primary vitrectomy for the treatment of rhegmatogenous retinal detachment came up with success rates from 64% to 100% for the primary procedure – some of the reports, however, had a relatively small number of cases and some with an additional buckle procedure (SPR Study-Group 2003). Unfortunately, an anatomically satisfying outcome does not mean a flawless functional result for the patients. As Heimann pointed out in his study, about 40% of patients will not achieve reading ability after any type of surgery, about 10–40% will need more than one surgical procedure (which includes retinopexy and some form of cataract surgery later on) and about 5% of eyes will have permanent anatomical and functional failure (Heimann et al. 2007).
The reputation – or perception – of primary vitrectomy as the more sophisticated method, an approach seemingly appropriate for the 21st century in contrast to buckling surgery with its rather antiquated appeal, has lead to an ever increasing number of ophthalmic surgeons primarily (or exclusively) trained in vitrectomy. In the United Kingdom, PPV is now the method of choice in 70–80% of all cases of retinal detachment (Wickham et al. 2007). In some clinics, the use of PPV on patients with retinal detachment rose from 1% to almost 50% within a decade without a real benefit in functional results compared to buckling surgery Johannson et al. 2006). Just recently, Heimann pointed out that while the choice of primary vitrectomy for the treatment of rhegmatogenous retinal detachment has grown in popularity, this trend has not been supported by the clinical results. Clinical trials comparing primary vitrectomy and buckling surgery have failed to demonstrate an advantage of the former over the latter. One multicenter prospective clinical trial compared both procedures with regard to the anatomical success rates (on which our study focusses). Patients after buckling surgery had a 28% greater likelihood of anatomical success than patients in the vitrectomy group (Ahmadieh et al. 2005).
The SPR study with 681 enrolled patients in 25 clinical centres found an advantage for phakic patients in the scleral buckling group regarding the main end-point (change in visual acuity) but no difference in functional outcome among pseudophakic patients. While according to the SPR, primary vitrectomy combined with a scleral buckle seems to be established in more complicated types of retinal detachment in patients with pseudophakia, PPV does not offer an advantage over scleral buckling in patients with phakia (Heimann et al. 2008).
An advantage of our study – as we see it – is the large number of patients who were involved. Our analysis led to the conclusion that macula-off correlates to a less favourable anatomical outcome. This is not to say that macula-off in itself is a risk factor for a lower anatomical success rate. In a disease that starts in the periphery of the retina, it seems rather logical to the authors that detachments with macula-off are the more severe form of this disease, stretching over a larger sector than a anatomically limited detachment far from the macula and often already existing for a longer period of time before being treated surgically (remember the relatively high percentage of symptom-free patients!). As new research indicates, the first 3 days seem to represent a relatively safe period during which surgery for macula-off retinal detachment may be postponed without compromising the patient’s visual prognosis (Heinrich et al. 2009).
However, we believe that after that period of time, a further delay of surgery should be avoided.
A purely retrospective study like the one presented here certainly has some potential weaknesses: We are aware that our definition of ‘anatomical success’ is determined by the postoperative management of our patients and describes a morphological state relatively close to the operation, without regard for the functional outcome. Covering a relatively large geographical area, our patients went back to the care of their primary ophthalmologist after dismissal from the hospital. Because there were no any other vitreoretinal centres in the region until approximately 1995, it can be assumed that any of our patients suffering another retinal detachment on the operated eye would have been referred to us once again for further surgery. Only those patients were enrolled in MUSTARD that did not require another operation for retinal detachment in our clinic. With more surgeons doing vitreoretinal interventions in our region since approximately 1995, the chances of us losing track of patients who have undergone primary surgery in our clinic have become greater. Therefore, anatomical success has been defined by the situation at the time when the patient left our clinic. This covers, admittedly, only a very short postoperative period. Unfortunately, with the data we have, we cannot contribute to the knowledge about the incidence of redetachment in the months and years following buckling surgery. A recent study has reported redetachment after buckling surgery in 7% of patients after a 6-month follow-up and in 5% of patients after a 12-month follow-up. The authors of that study have concluded that while conventional scleral buckling surgery is a reliable procedure in eyes with primary retinal detachment, in eyes with a retinal tear of more than three disc diameters in cumulative size, a primary vitrectomy should be considered. The authors recommended a follow-up through more than 6 months to evaluate the anatomical and visual outcomes after buckling surgery (Goezinne et al. 2010).
During the period in which the operations covered in MUSTARD took place, not only surgical procedures changed and evolved, there was also a rapid development of new diagnostic techniques. Currently, at the end of the first decade of the 21st century, the documentation at the end of the surgical procedure (consisting of a detailed report and a drawing by the surgeon) would – in most cases – no longer be considered adequate to determine whether anatomical success as defined in this paper had been achieved. A spectral-domain OCT, for instance, is a significant progress in evaluating the reattachment of a previously detached macula before the patients’ dismissal from the hospital (Nakanishi et al. 2009). In this retrospective study, we were not able to determine the functional outcome of the retinal surgery conducted in our clinic because of the process of postoperative care in our region. When the patients left the clinic, they were still mydriatic and in some cases they still had remnants of ointment on their cornea, which would have made testing the visual acuity and other functions difficult. Further management and care lay in the hands of other ophthalmologists from whom we did not receive any routine feedback.
Furthermore, it was beyond the limits of our documentation to determine whether and how much proliferative vitreoretinopathy existed in patients who had undergone buckling surgery. Complications – if they arose – were mainly treated by the referring ophthalmologists, not by our clinic. Therefore, we cannot contribute to a comparison of which procedures are associated with the more severe complications. In any discussions about the strengths and weakness of buckling surgery versus PPV, it must kept in mind that scleral buckling can – to name the most frequent complications – result in refractive changes, motility disturbances, vitreous or retinal incarceration, suprachoroidal or subretinal haemorrhage or migration of the buckling elements. The major disadvantages of PPV are (besides those mentioned earlier) its potential to induce cataract, increase IOP and lead to new breaks and/or retinal trauma (Schwartz & Flynn 2006).
Further evaluation of the case series analysed by MUSTARD will hopefully shed more light on the success rates of scleral buckling relative to the factors besides the macula-off versus macula-on differences described here.