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Implicit case review
Ophthalmology Volume 110, Number 4, April 2003 ments derived through persistent treatment effects may be offset by increased expenditures. While our cost-effective analyses may have some limitations, given the paucity of economic models designed to evaluate emerging ophthalmic technologies that currently appear in the peer-reviewed literature, I believe that our research represents a small step in the right direction for the evaluation of an important and efficacious new treatment for AMD. SANJAY SHARMA, MD, FRCSC, MSC (EPID), MBA Kingston, Ontario, Canada References 1. Sharma S, Brown GC, Brown MM, et al. The cost-effectiveness of photodynamic therapy for fellow eyes with subfoveal choroidal neovascularization secondary to age-related macular degeneration. Ophthalmology 2001;108:2051–9. 2. Drummond MF, Richardson WS, O’Brien BJ, et al. Users’ guides to the medical literature. XIII. How to use an article on economic analysis of clinical practice. A. Are the results of the study valid? JAMA 1997;277:1552–7. 3. Friedberg M, Saffran B, Stinson TJ, et al. Evaluation of conflict of interest in economic analyses of new drugs used in oncology. JAMA 1999;20;282:1453–7. 4. Torrance GW. Measurement of health state utilities for economic appraisal. J Health Econ 1986;5:1–30. 5. Brown GC, Brown MM, Sharma S. Difference between ophthalmologists’ and patients’ perceptions of quality of life associated with age-related macular degeneration. Can J Ophthalmol 2000;35:127–33. 6. Sharma S. Levels of evidence and interventional ophthalmology. Can J Ophthalmol 1997;32:359 – 62.
Wieger’s Ligament Dear Editor: Based on their recent experience of endoscopic methods for separation of Wieger’s ligament from the posterior lens capsule, Torii and colleagues feel that surgical manipulation of the anterior hyaloid membrane warrants further investigation, for example in diabetic vitrectomy.1 However, there is already a long (20 year) experience of such mechanical modulation of the behaviour of the aschaemic diabetic eye postvitrectomy.2,3 The rationale was founded upon (1) the ready separation of the anterior vitreous face from the lens during intracapsular cataract extraction in older patients, (2) the observation of Michels that drainage of red blood cells through the trabecular meshwork and a clear vitreous cavity are characteristic features of the aphakic vitrectomised diabetic eye, albeit with a high risk of rubeosis iridis,4 and (3) the introduction of scatter endophotocoagulation in the early 1980s to reduce the aschaemic drive to neovascularisation following vitrectomy.5 Using coaxial illumination and peripheral scleral indentation, a direct suction and cutting technique similar to that described by Torii and colleagues creates a localised separation and disruption of Wieger’s ligament. This is usually undertaken inferotemporally in phakic eyes for ease of access and may be facilitated by an arc of blood-staining of the inferior part of the vitreolenticular adhesion. Successful accomplishment of “pseudo-aphakia” is confirmed postoperatively by the equal suspension of red blood cells in
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the aqueous fluid of the anterior chamber and vitreous cavity on biomicroscopic examination. Such pseudo-aphakia can also arise inadvertently during vitrectomy, presumably through incarceration and disruption of the anterior hyaloid membrane in relation to an anteriorly-located pars plana entry site. In eyes that have undergone extracapsular cataract surgery, “pseudophakic pseudo-aphakia” can easily be achieved by peripheral iridectomy “from behind” at 12.00 o’clock, the suction cutter creating a small hole in the zonule and anterior hyaloid face as well as in the iris and thus ensuring free egress of red cells via the angle. Pseudo-aphakia facilitates spontaneous clearance of vitreous cavity hemorrhage immediately postvitrectomy without precipitating erythroclastic glaucoma or iris neovascularisation provided radical debulking of basal intragel haemorrhage and scatter endolaser are also undertaken. By decompartmentalizing the vitreous cavity, localized disruption of Wieger’s ligament also appears to militate against the development of entry-site neovascularisation and delayed postvitrectomy vitreous cavity hemorrhage,2 so complete removal of the anterior hyaloid scaffold for post-vitrectomy fibrovascular proliferation, as advocated by Torii and colleagues, may well be unnecessarily intrusive. DAVID MCLEOD, FRCOPHTH Manchester, England References 1. Torii H, Takahashi K, Yoshitomi F, et al. Mechanical detachment of the anterior hyaloid membrane from the posterior lens capsule. Ophthalmology 2001;108:2182–5. 2. McLeod D. Microsurgical management of neovascularisation secondary to posterior segment ischaemia. Eye 1991;5:252–9. 3. McLeod D. Entry site neovascularisation after diabetic vitrectomy [editorial]. Br J Ophthalmol 2000;84:810 –1. 4. Michels RG. Vitrectomy for complications of diabetic retinopathy. Arch Ophthalmol 1978;96:237– 46. 5. Charles S. Vitrectomy for retinal detachment. Trans Ophthalmol Soc UK 1980;100:542–9.
Implicit Case Review Dear Editor: Medical malpractice in the United States is unfortunately based upon an adversarial system of case review. Medical experts for plaintiff and defense are recruited to testify based on review of the same objective clinical data but they usually arrive at different conclusions with regard to the “standard of care”. Despite the critical role for these medical experts in these cases there has been little study of the reliability, reproducibility, and validity of this method. Margo1 compared inter-rater and inter-group agreement in judging compliance with the standard of care using an implicit case review process. He reported that unstructured implicit review was not a reliable method and recommended that a more explicit format based on established clinical guidelines might be more valid. Over the past several years, I have served as an expert witness for both sides. Most of the cases center around four questions: 1) Did the medical providers meet their obligation in the evaluation of the patient?
Letters to the Editor 2) If there was a sin of commission or omission did this result directly and causally in a harm to the patient? 3) Would earlier diagnosis and treatment have made a difference? 4) Was the harm that the patient suffered significant? In other words, there is more to being a medical expert than determining the standard of care and there is more to malpractice than simply a breach of that standard. It has been my experience that this term (standard of care) has little meaning to clinicians and published guidelines and the literature usually do not directly address the issue of a standard of care. I believe that existing published clinical guidelines have only been useful for defining egregious acts of malpractice. It has also been my experience that these cases of clear medical error rarely make it to court and are usually settled outright. In addition, cases with clearly documented and good quality care but with nonforseable, nonpreventable, or negative but expected outcomes also end up being dismissed or settled. It is the ambiguous cases that often are the setting for the battle of the experts. I would think that these more complex cases would be difficult to subject to an explicit review process. In addition, there are situations where there is a breach that can be defined by explicit criteria but the case review finds no malpractice based upon more subjective criteria. For example: 1) If there was a breach of the standard of care but it did not result directly in a harm (e.g. no intraocular pressure measurement taken in a patient but the patient had an unrelated corneal abrasion) 2) If there was a breach that led to an insignificant harm (e.g. the patient was dilated with cyclopentolate instead of tropicamide but it wore off after a few days without sequelae) 3) If there was a breach but it made no difference in the final outcome (e.g. failure to diagnose a malignant brain tumor that is ultimately diagnosed 2 weeks later) It is in these situations that explicit guidelines are not generally available and implicit review is usually necessary based upon reviewer experience and expertise. It seemed to me from Dr. Margo’s data in Table 2 that the concordance rate for specialists reviewing the case was relatively good (at least for case 1). The author points out that inter-rater disagreement in implicit review might represent reviewer bias, tendency to judge more harshly if a serious adverse outcome or permanent disability occurred, or if there is lack of clear conclusive evidence on efficacy of therapy. In my consulting experience these are precisely the issues that are least amenable to explicit review criteria. The reliability of the unstructured implicit review in the reported cases was judged to be poor but I wonder if Dr. Margo could comment on the following questions: 1. What was the “gold standard” answer (by explicit criteria) if any for these two cases? 2. If explicit criteria were applied to the cases would the physician reviewers still have discordant results?
3. Would the concordance rate for an implicit review be higher if example cases that were or were not clearly malpractice (by explicit criteria) were used rather than cases that could be interpreted either way? I think that the authors work raises important and fascinating questions and I commend Dr. Margo for his efforts in this area. ANDREW G. LEE, MD Iowa City, Iowa Reference 1. Margo CE. Peer and expert opinion and the reliability of implicit case review. Ophthalmology 2002;109:614 – 8.
Author reply Dear Editor: Although my study was not designed to test the reliability of explicit case review or the influencing affect that malpractice might have on the outcome of implict review, I am happy to offer my opinions in response to Dr. Lee’s questions. Without getting bogged down in the details of the two cases, I suspect that an explicit case review would give greater concordance, based on the assumption that the review consists of a formal check list that documented compliance with evidenced-based standards of care. One potential problem, however, is identifying clinically relevant guidelines, especially for case 2. If, for example, explicit case review of case 1 was formulated from guidelines from the Preferred Practice Patterns: Management of Posterior Vitreous Detachments, Retinal Breaks and Lattice Degeneration, from the American Academy of Ophthalmology,1 the initial physician could have been cited for not performing (or documenting) a retina examination with scleral depression. Explicit guidelines in this context are relatively unambiguous and easy to apply, but they do not take into account the skill of the examiner and fail to address the cognitive processes needed to solve clinical problems. The use of an explicit review for case 2 is complicated by the fact that potential guidelines for standards of care for the presenting problems (decreased vision, eye pain, and corneal edema) would be rather broad and it is unclear which problem, or problems, should be selected. If ones objectively reviews the performance of the ophthalmologist in Case 2 with regard to the most specific clinical problemcorneal edema, one finds that he documented the necessary components of the clinical evaluation, namely relevant past and current history, slit lamp examination, measurement of intraocular pressure, gonioscopy and optic disc examination. The apparent reason for failure to diagnose angleclosure glaucoma was misinterpretation of gonioscopy. I believe that most peers and experts if asked to apply an explicit “check list” for the evaluation of corneal edema in this situation would find the evaluation complete. An explicit review does not need a “gold standard” to be valid, but it does require evidence-based data for meaningful guidelines. For many clinical situations there is a paucity of evidence-based data from which to develop standardized
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Wieger’s Ligament Dear Editor: Based on their recent experience of endoscopic methods for separation of Wieger’s ligament from the posterior lens capsule, Torii and colleagues feel that surgical manipulation of the anterior hyaloid membrane warrants further investigation, for example in diabetic vitrectomy.1 However, there is already a long (20 year) experience of such mechanical modulation of the behaviour of the aschaemic diabetic eye postvitrectomy.2,3 The rationale was founded upon (1) the ready separation of the anterior vitreous face from the lens during intracapsular cataract extraction in older patients, (2) the observation of Michels that drainage of red blood cells through the trabecular meshwork and a clear vitreous cavity are characteristic features of the aphakic vitrectomised diabetic eye, albeit with a high risk of rubeosis iridis,4 and (3) the introduction of scatter endophotocoagulation in the early 1980s to reduce the aschaemic drive to neovascularisation following vitrectomy.5 Using coaxial illumination and peripheral scleral indentation, a direct suction and cutting technique similar to that described by Torii and colleagues creates a localised separation and disruption of Wieger’s ligament. This is usually undertaken inferotemporally in phakic eyes for ease of access and may be facilitated by an arc of blood-staining of the inferior part of the vitreolenticular adhesion. Successful accomplishment of “pseudo-aphakia” is confirmed postoperatively by the equal suspension of red blood cells in
628
the aqueous fluid of the anterior chamber and vitreous cavity on biomicroscopic examination. Such pseudo-aphakia can also arise inadvertently during vitrectomy, presumably through incarceration and disruption of the anterior hyaloid membrane in relation to an anteriorly-located pars plana entry site. In eyes that have undergone extracapsular cataract surgery, “pseudophakic pseudo-aphakia” can easily be achieved by peripheral iridectomy “from behind” at 12.00 o’clock, the suction cutter creating a small hole in the zonule and anterior hyaloid face as well as in the iris and thus ensuring free egress of red cells via the angle. Pseudo-aphakia facilitates spontaneous clearance of vitreous cavity hemorrhage immediately postvitrectomy without precipitating erythroclastic glaucoma or iris neovascularisation provided radical debulking of basal intragel haemorrhage and scatter endolaser are also undertaken. By decompartmentalizing the vitreous cavity, localized disruption of Wieger’s ligament also appears to militate against the development of entry-site neovascularisation and delayed postvitrectomy vitreous cavity hemorrhage,2 so complete removal of the anterior hyaloid scaffold for post-vitrectomy fibrovascular proliferation, as advocated by Torii and colleagues, may well be unnecessarily intrusive. DAVID MCLEOD, FRCOPHTH Manchester, England References 1. Torii H, Takahashi K, Yoshitomi F, et al. Mechanical detachment of the anterior hyaloid membrane from the posterior lens capsule. Ophthalmology 2001;108:2182–5. 2. McLeod D. Microsurgical management of neovascularisation secondary to posterior segment ischaemia. Eye 1991;5:252–9. 3. McLeod D. Entry site neovascularisation after diabetic vitrectomy [editorial]. Br J Ophthalmol 2000;84:810 –1. 4. Michels RG. Vitrectomy for complications of diabetic retinopathy. Arch Ophthalmol 1978;96:237– 46. 5. Charles S. Vitrectomy for retinal detachment. Trans Ophthalmol Soc UK 1980;100:542–9.
Implicit Case Review Dear Editor: Medical malpractice in the United States is unfortunately based upon an adversarial system of case review. Medical experts for plaintiff and defense are recruited to testify based on review of the same objective clinical data but they usually arrive at different conclusions with regard to the “standard of care”. Despite the critical role for these medical experts in these cases there has been little study of the reliability, reproducibility, and validity of this method. Margo1 compared inter-rater and inter-group agreement in judging compliance with the standard of care using an implicit case review process. He reported that unstructured implicit review was not a reliable method and recommended that a more explicit format based on established clinical guidelines might be more valid. Over the past several years, I have served as an expert witness for both sides. Most of the cases center around four questions: 1) Did the medical providers meet their obligation in the evaluation of the patient?
Letters to the Editor 2) If there was a sin of commission or omission did this result directly and causally in a harm to the patient? 3) Would earlier diagnosis and treatment have made a difference? 4) Was the harm that the patient suffered significant? In other words, there is more to being a medical expert than determining the standard of care and there is more to malpractice than simply a breach of that standard. It has been my experience that this term (standard of care) has little meaning to clinicians and published guidelines and the literature usually do not directly address the issue of a standard of care. I believe that existing published clinical guidelines have only been useful for defining egregious acts of malpractice. It has also been my experience that these cases of clear medical error rarely make it to court and are usually settled outright. In addition, cases with clearly documented and good quality care but with nonforseable, nonpreventable, or negative but expected outcomes also end up being dismissed or settled. It is the ambiguous cases that often are the setting for the battle of the experts. I would think that these more complex cases would be difficult to subject to an explicit review process. In addition, there are situations where there is a breach that can be defined by explicit criteria but the case review finds no malpractice based upon more subjective criteria. For example: 1) If there was a breach of the standard of care but it did not result directly in a harm (e.g. no intraocular pressure measurement taken in a patient but the patient had an unrelated corneal abrasion) 2) If there was a breach that led to an insignificant harm (e.g. the patient was dilated with cyclopentolate instead of tropicamide but it wore off after a few days without sequelae) 3) If there was a breach but it made no difference in the final outcome (e.g. failure to diagnose a malignant brain tumor that is ultimately diagnosed 2 weeks later) It is in these situations that explicit guidelines are not generally available and implicit review is usually necessary based upon reviewer experience and expertise. It seemed to me from Dr. Margo’s data in Table 2 that the concordance rate for specialists reviewing the case was relatively good (at least for case 1). The author points out that inter-rater disagreement in implicit review might represent reviewer bias, tendency to judge more harshly if a serious adverse outcome or permanent disability occurred, or if there is lack of clear conclusive evidence on efficacy of therapy. In my consulting experience these are precisely the issues that are least amenable to explicit review criteria. The reliability of the unstructured implicit review in the reported cases was judged to be poor but I wonder if Dr. Margo could comment on the following questions: 1. What was the “gold standard” answer (by explicit criteria) if any for these two cases? 2. If explicit criteria were applied to the cases would the physician reviewers still have discordant results?
3. Would the concordance rate for an implicit review be higher if example cases that were or were not clearly malpractice (by explicit criteria) were used rather than cases that could be interpreted either way? I think that the authors work raises important and fascinating questions and I commend Dr. Margo for his efforts in this area. ANDREW G. LEE, MD Iowa City, Iowa Reference 1. Margo CE. Peer and expert opinion and the reliability of implicit case review. Ophthalmology 2002;109:614 – 8.
Author reply Dear Editor: Although my study was not designed to test the reliability of explicit case review or the influencing affect that malpractice might have on the outcome of implict review, I am happy to offer my opinions in response to Dr. Lee’s questions. Without getting bogged down in the details of the two cases, I suspect that an explicit case review would give greater concordance, based on the assumption that the review consists of a formal check list that documented compliance with evidenced-based standards of care. One potential problem, however, is identifying clinically relevant guidelines, especially for case 2. If, for example, explicit case review of case 1 was formulated from guidelines from the Preferred Practice Patterns: Management of Posterior Vitreous Detachments, Retinal Breaks and Lattice Degeneration, from the American Academy of Ophthalmology,1 the initial physician could have been cited for not performing (or documenting) a retina examination with scleral depression. Explicit guidelines in this context are relatively unambiguous and easy to apply, but they do not take into account the skill of the examiner and fail to address the cognitive processes needed to solve clinical problems. The use of an explicit review for case 2 is complicated by the fact that potential guidelines for standards of care for the presenting problems (decreased vision, eye pain, and corneal edema) would be rather broad and it is unclear which problem, or problems, should be selected. If ones objectively reviews the performance of the ophthalmologist in Case 2 with regard to the most specific clinical problemcorneal edema, one finds that he documented the necessary components of the clinical evaluation, namely relevant past and current history, slit lamp examination, measurement of intraocular pressure, gonioscopy and optic disc examination. The apparent reason for failure to diagnose angleclosure glaucoma was misinterpretation of gonioscopy. I believe that most peers and experts if asked to apply an explicit “check list” for the evaluation of corneal edema in this situation would find the evaluation complete. An explicit review does not need a “gold standard” to be valid, but it does require evidence-based data for meaningful guidelines. For many clinical situations there is a paucity of evidence-based data from which to develop standardized
629