what is evident in evidence? epistemology and ethics in coloproctology
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What is evident in evidence? Epistemology and ethics in coloproctology
Pier Paolo Dal MonteBologna, Italy
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Sulayman told Bilqis, "Enter the courtyard." The courtyard was very smooth without any curvature in its glass. When Bilqis saw it, she thought that it was water and had depth,
so she bared her legs so as not to let the water dampen her clothes.
By that, Sulayman informed her that the throne which she saw was of this sort."
Mujiadin Ibn Arabi, Fusus al-Hikam (Commentary to Quran 27,44)
Illusion plays its tricks especially in affairs which cannot be clearly perceived by the senses
Hazrat Shihabuddin Yahya al-Suhrawardi, Hayakal al-Nur
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I spoke in the mosque of Damascus by way of a sermon but to a congregation whose hearts were withered and dead, not having travelled from the
world of form, to the world of meaning. Mosleh al-Din Saadi Shirazi, Golestan
Human reason is drowned, like the high mountains, in the flood of illusion and vain imaginations
Maulana Jalalu-’d-din Muhammad i Rumi, Masnavi i Ma’navi.
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How we know(what we know, what we think to know, what we do not know)
EpistemologyFrom Greek Epi- Histomai: “being above”
Related to knowledge: the principles of our knowledge
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From indoeuropean -Dha: “what is established” and Sva-: “Self”Sanscrit: Svadha: “what is established for
ourselves”, “personal way”, “fate”, “destiny”
The “science” concerning the right behaviour
From the Greek Ethos: “behaviour”
Ethics
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Medical EthicsThe primary goals of medical practice, for the entire
history, have been defined in terms of benefit for individual patients
Medical epistemologyThe most appropriated knowledge (methods) to pursue
the benefit for individual patients
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EpistemologyThe knowledge of the “principles”Theoria
Ethos (vita activa)
Action (praxis): managed by prudence Production (poiesis): managed by art (teknè)
Oiko-nomia Labour: activity connected to biological needs of human being
(atekne tribè)
Bios: vita quam vivimus
Zoé: vita qua vivimus
The traditional hyerarchy of knowledge and action
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Medical Knowledge
Education/literacyExperience
Mastery/expertise
Clinical judgment
ObservationIntuition
Interaction with the patient
Implicit knowledge(Polanyi’s Tacit knowledge)
Medical paternalismIpse dixit
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Basic Sciences (Physics, Biochemistry, molecular sciences)
AnatomyPathophysiology
LiteratureClinical epidemiology
EBM
Explicit knowledge
Medical Knowledge
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All human knowledge has a practical dimension rooted in the accretions of experience and memory. Humans can obtain
knowledge only by interacting with their environments, so any knowledge that humans can use necessarily has both tacit and
explicit components.
Tacit knowing refers to the taken-for-granted knowledge at the periphery of attention that allows people to understand
the world and discern meaning in it.Michael Polanyi. Personal Knowledge: Towards a Post-Critical Philosophy. London: Routledge and Kegan Paul; 1962.
Implicit knowledge
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Implicit + explicit knowledge: How we know the reality
The totality of our beliefs is like a web. Those sentences that lie closest to the periphery of the web are the
“observation sentences”, while the interior of the web contains more theoretical claims.
"Our statements about the external world face the tribunal of sense experience not individually but only as a corporate body. Thus our
theories are put to the test as a whole; we cannot simply test individual claims in isolation from the rest of our theory.”
WV Quine: The web of beliefQuine WV: From a Logical Point of View. Cambridge, MA, Harvard University Press; 1953.
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EBMBasic Sciences
Anatomy
Pathophysiology
Experience
Mastery/expertise
Clinical judgment
Observation
Intuition
Interaction with the patient
The web of belief in Medical decision
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Medicine as if it was an hard science
Evidence Based Medicine
The conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients
Sackett DL, Straus SE, Richardson WS, Rosenberg W and Haynes RB: Evidence-Based Medicine: How to Practice and Teach EBM. 2ndth edition. Edinburgh, Churchill Livingstone; 2000. 15
The term "evidence-based medicine" in an overly broad manner.
The best findings from health care research that are both valid and ready for clinical application
Haynes RB: What kind of evidence is it that Evidence-Based Medicine advocates want health care providers and consumers to pay attention to? BMC Health Serv Res 2002, 2:3 15
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These definitions seem merely to say that EBM is the wise use of the best evidence available.
Who could possibly be opposed to using the best
evidence wisely?
Scott R Sehon and Donald E Stanley. BMC Health Services Research 2003, 3:14
Evidence Based Medicine
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Ethics and EBM epistemologyThe moral imperative
EBM epistemological claim: EBM is the most effective means of pursuing health. Thus, EBM, rather than
medicine-as-usual, should be the main method of pursuing health.
M. Gupta: Journal of Evaluation in Clinical Practice, 9, 2, 111–121
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If research data are generated by EBM-preferred methods, they are unlikely to reflect biases.
Postulate of EBM
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No equation can represent exactly an event, whatever it is
Thomas Kuhn: The structure of scientific revolutions
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EBM Biases
1) Sources of research funding.
Studies of interventions that are likely to have commercial value are more likely to receive funding from the businesses Data created by commercial funders are more likely to demonstrate the effectiveness of the sponsored intervention
Cho M.K. & Bero L.A. (1996) . Annals of Internal Medicine 124, 485–489.
...Plus: conflict of interests, bribery (called sponsoring), corruption, etc, etc
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EBM Biases
1) Sources of research funding.
The Golden Rule:
Who has the gold, makes the rules
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2) Technical Bias. Evidence hierarchy privileges certain types of data and certain types of research methodologies (easy to investigate, quantifiable) Culpepper L. & Gilbert T.T. (1999) Evidence and ethics. Lancet 353, 829–831.
EBM Biases
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3) Publication biases
Publication bias, refers to the differential publication by medical journals of positive and/or statistically significant results
Because publications count significantly towards researchers’ career advancement , they may choose to study a restricted group of topics that are most likely to yield publishable results.
Blau J.N. (1997) Evidence-based medicine. Journal of Evaluation in Clinical Practice 3, 149–151.Black D. (1998) Limitations of evidence. Journal of the Royal College of Physicians of London 32, 23–26.
Gilbody S.M. & Song F. (2000). Psychological Medicine 30, 253–258Miettinen O.S. (1998) y. Canadian Medical Association Journal 158, 215–221.
Naylor C.D. (1995). The Lancet 345, 840–842.
EBM Biases
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No double blind studiesSurgical technique bias
Surgeon’s skills/experience bias
In surgery there are few more biases
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(SH) significantly more likely to have recurrent hemorrhoids in long term follow up than those receiving conventional hemorrhoidectomy (CH)
SH significantly higher proportion of patients with symptom of prolapse Non significant trends in favor of SH in pain, pruritus ani, and fecal urgency. All other clinical parameters showed trends favoring CH
CONCLUSIONS: Stapled hemorrhoidopexy is associated with a higher long-term risk of hemorrhoid recurrence and the symptom of prolapse. If hemorrhoid recurrence and prolapse are the most important clinical outcomes, then conventional excisional surgery remains the "gold standard" in the surgical treatment of internal hemorrhoids.
EBM Systematic reviews of comparison between SH and conventional surgery
Staples versus conventional surgery for hemorrhoids. Jayaraman S; Colquhoun PH; Malthaner. Cochrane Database Of Systematic Reviews 2006 Oct 18
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Stapled hemorrhoidopexy less operating time , earlier return of bowel function and shorter hospital stay . There was less pain after SH, The patients' satisfaction was significantly higher with stapled hemorrhoidopexy than conventional hemorrhoidectomy .
Although there was increase in the recurrence of hemorrhoids , the overall incidence of recurrent hemorrhoidal symptoms recurrence rate was similar. The overall complication rate did not differ significantly from that of conventional procedure .
Conclusions: SH is safe with many short-term benefits. The long-term results are similar to conventional procedure.
Systematic review on the procedure for prolapse and hemorrhoids Tjandra JJ; Chan MK. Diseases Of The Colon And Rectum [Dis Colon Rectum] 2007 Jun; Vol. 50 (6), pp. 878-92.
EBM Systematic reviews of comparison between SH and conventional surgery
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So, where is the truth?
The situation is even worse for the “evidences” regarding the fistula’s treatments
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The success rates reported to date range from 0% to 100%. (!!!!)
Fistulotomy remains the surest way of dealing with fistulae, but is appropriate only in patients in whom such a strategy is associated with minimal risk to sphincteric function. For the remainder of patients, the technique of fibrin glue is yet another addition to the surgical armamentarium.
The potential advantages of the technique however, have yet to be translated into consistent reports of long-term success.
Fibrin glue in the management of anal fistulaeT. M. Hammond*, M. F. Grahn* and P. J. Lunniss*. Colorectal Disease, 2004 6, 308–319
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Meta-analysis of fibrin glue versus surgery for treatment of fistula-in-ano.
Cirocchi R et al. Ann Ital Chir 2010 Sep-Oct; Vol. 81 (5), pp. 349-56.
Our statistical analysis does not show any significant statistical difference between fibrin glue treatment versus conventional surgical treatment for all perianal fistulae in terms of recurrence (P = 0.23) and anal incontinence (P = 1.00).
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..Apart from the small size and absence of long-term follow up in the available studies….lack of measurement of objective evidence of fistula healing (endorectal ultrasound or magnetic resonance imaging).
The initial results with AFP are encouraging with success rate of up to 35–87% in complex fistulae-in-ano. As it appears to be a safe procedure associated with little morbidity and low risk of incontinence,
AFP can be recommended for treating complex fistulae-in-ano.
The efficacy of anal fistula plug in fistula-in-ano: a systematic reviewP. Garg et al. Colorectal Disease 2010. 12, 965–970
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This meta-analysis suggests that a policy of incision and drainage for primary acute anorectal abscess–fistula is adequate in many instances as it is simple, even in the hand of junior surgeons, but suffers from recurrence. Elective fistulotomy should be reserved for the proportion of patient who developed recurrence subsequently. On the other hand, immediate fistulotomy is associated with a tendency to higher risk of minor postoperative faecal incontinence to flatus and soiling, although this is not statistically signif icant in the pooled analysis.
There is no conclusive evidence in the meta-analysis to show which method is better. Future randomized trials when pooled further in the meta-analysis may answer this question.
Meta-analysis of randomized clinical trials comparing drainage alone vs primary sphincter-cutting procedures for anorectal abscess–fistula
H. M. Quah et al. Int J Colorectal Dis (2006) 21: 602–609
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The level of evidence for treatment is low, because relevant randomized trials are scarce. The indication for treatment is established by the clinical history and physical examination.
Surgical treatment is with one of the following operations: laying open, seton drainage, plastic surgical reconstruction with suturing of the sphincter, and occlusion with biomaterials. Only superficial fistulae should be laid open. The risk of postoperative incontinence is directly related to the thickness of sphincter muscle that is divided. All high anal fistulae should be treated with a sphincter-saving procedure. The various plastic surgical reconstructive procedures all yield roughly the same results. Occlusion with biomaterials yields a lower cure rate.
Cryptoglandular anal fistulas.Ommer A et al. Dtsch Arztebl Int 2011 Oct; Vol. 108 (42), pp. 707-13.
Conclusion: This is the first German S3 guideline for the treatment of cryptoglandular anal fistula. It includes recommendations for the diagnostic evaluation and treatment of this clinical entity.
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Most studies on anal fistula are small and heterogeneous with respect to interventions and patient groups included making it difficult to draw strong inferences.
Marsupialization after fistulotomy reduces bleeding and allows for faster healing. Chemical setons produce more pain postoperatively but evidence on recurrence and healing rates remains inconclusive. Early results suggest that flap repair of anal fistulae may be no worse than fistulotomy Radiofrequency fistulotomy produces less pain on the first day postoperatively and may allow for shorter healing times. The role of fistulotomy at time of abscess incision remains to be clarified definitively.
Basic questions remain to be answered.
Surgical management of anal fistulae: a systematic reviewA. I. Malik and R. L. Nelson. Colorectal Disease 2008, 10, 420–430
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….so, what do we know now in order to discern among the differnt fistula treatments, especially
for complex fistule?
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There are very few randomized controlled trials comparing the various modalities of surgery for
fistula in ano.
There is a paucity of good quality data that compares various types of operative treatment for anorectal
fistula and there is scope for further trials in the area
Jacob TJ, Perakath B, Keighley: The Cochrane Database of Systematic Reviews 2011
There seems to be no major difference between the various techniques as far as recurrence rates are concerned
The answer is:….NOTHING!
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EBM
Basic SciencesAnatomy
PathophysiologyExperience
Mastery/expertise
Clinical judgment
Observation
Intuition
Interaction with the patient
The web of belief in Medical decision
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Even when a clinical trial returns positive results that satisfy tests of statistical significance, we will have more confidence in these results when they have some biological plausibility.
Goodman Steven N.: Towards Evidence-Based Medical Statistics. 1: The P Value Fallacy. Annals of Internal Medicine 1999, 130:995-1004.
Example: the “Rectal Redundancy Syndrome”
Pathophysiology
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The need to extend the sphincter incision is a parameter that treatment is complicated.
High Transphincteric FistulaeSuprasphicteric FistulaeExtrasphincteric Fistulae
Parks A G, Stitz R W: The treatment of high fistula-in-ano. Dis.Colon Rectum 19:487-491, 1976.
Anatomy
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Relapse rate is underestimatedLack of long term studies
The relapse rate for complex fistulae treated with “conservative treatments” (i.e. lay open) is
reasonably higher than 50%
Observation, inuition, experience
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Remedies originates from the patients analysis, not by giving a collective name to the disease that afflicts him
Augusto Murri
Interaction with the patient
...Unfortunately the poor mankind was not born in Wien, but somewhere in Africa
Giorgio de Santillana: Lecture about Psychoanalysis at the Congress of American Cardiology Society, 1965
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Age / Sphincter integrityCausal or associated diseases
Crohn TubercolosisPelvic sepsis
CancerTrauma
RadiotherapyIatrogenic
DiabetesHearth diseasesVasculopathiesSteroid therapy
etc.etc.etc.
Individual caracteristics of the patient
Interaction with the patient
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180 pts (93 high fistulas involving more than 1 cm of external anal sphincter – 84 with an adequate f.u.) 48/84 (57 %) pts treated by fistulotomy Healing rate in high fistulas lay open: 96% Operation induced Incontinence : 30% flatus, 4% soft stool, 2% hard stool – 8% use of pads
…Our results suggest lay open of any fistula deemed suitable has a high success rate as well as a consistent and predictable risk of flatus leakage and mucus discharge of no more than a teaspoonful in 24h.
...But without medical paternalism bias
“For many high anal fistulas, lay open is still a good option”
GK Aktin, J Martins, P Tozer, P Ranchod, RKS Phillips. Tech ColoproctJune 2011
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Incontinence risk is an undetermined concept and it is conjugatd only at the present time
In people’s life can occurr many condition that can worsen “subclinical” problems of functional
integrity
Future pregnanciesFuture disease
Age
Patient as individual
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Causes of Recurrence
Complexity of the fistulaInadequate initial treatment
Crohn’s diseaseInadequate treatment of the postop wound
Inadequate follow-up Surgeon?
Pathophysiology and surgical technique
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Medical practice is not a problem akin to constructing and solving a series of mathematical equations; it is a problem akin to
understanding the interactions among persons.
Clinicians may choose to rely on clinical experience, evidence-based medicine, or some combination of the two, but both approaches
require tacit knowing.
Conclusions
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