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Computed tomography in suspected acute appendicitis
514
Letters to the Editors
Surgery April 2001
tion). Clinical scenarios that may predispose to obstruction obviously include previous intra-abdominal o p e r a t i o n (even as minimal as a distant appendectomy), especially after abdominal radiation therapy. Conversely, the astute surgeon will n o t exclude laparoscopic e x a m i n a t i o n of selected patients without an apparent predisposing cause of adhesions (eg, prior celiotomy) if there is suggestive evidence of obstruction--these patients may benefit most by the findings of internal hernias, clinically occult abdominal wall hernias, or even early malignancies. While l a p a r o s c o p i c e x p l o r a t i o n a n d adhesiolysis is p r o b a b l y the least invasive arrow in o u r t h e r a p e u t i c quiver, this consideration does not justify its indiscriminate use in patients with c h r o n i c a b d o m i n a l pain. We especially question its use in patients with u n e x p l a i n e d diffuse, n o n c r a m p y constant pain. T h e basic premise is that l a p a r o s c o p i c e x p l o r a t i o n s h o u l d be o f f e r e d to patients with s o m e convincing evidence o f visceral pain secondary to intestinal obstruction and not a b d o m i n a l wall (somatic) pain. Michael G. Sa~ MD Andrew L. Warshaw, MD References 1. Luque-de Le6n E, Metzger A, Tsiotos GG, Schlinkert RT, Sarr MG. Laparoscopic management of small bowel obstruction: indications and outcome. J Gastrointest Surg 1998;2:132-40. 2. Frank JW, Sarr MG, Camilleri M. Use of gastroduodenal manometry to differentiate mechanical and functional intestinal obstruction: an analysis of clinical outcome. Am J Gastroenterol 1994;89:339-44.
11/59/114220 doi: 10.1067/msy.2001.114220
Computed tomography in suspected acute appendicitis To the Editors: Weyant and his colleagues have m a d e a valuable contribution to the debate over the use of c o m p u t e d tomography (CT) in patients with suspected acute appendicitis. 1 In j u d g i n g the appropriate use of CT, it is useful to look at results in regimes that have n o t e m p l o y e d it. Thirty years ago, the m a n a g e m e n t o f these patients was clarified w h e n it was established that less than half r e q u i r e d an o p e r a t i o n and were o u t n u m b e r e d by a g r o u p whose complaints, t h o u g h at first suspicious of acute appendicitis (AA), settled without t r e a t m e n t over 24 to 48 hoursfl This syndrome was n a m e d Acute Nonspecific A b d o m i n a l Pain, or NSAP, and subsequent surveys t h r o u g h o u t the world c o n f i r m e d this observation in adults and children. 2 T h e s e facts necessarily have an effect o n m a n a g e ment. Patients who have clear signs o f AA or o t h e r acute pathology are, as usual, p r e p a r e d for operation. In those whose signs are m o r e doubtful, a formal policy of 3 to 4 hourly reviews (active observation) is c o m m e n c e d to separate those who steadily improve (and can be discharged with the label of NSAP) from those who, over time, devel-
op m o r e c o n v i n c i n g e v i d e n c e of disease a n d r e q u i r e either o p e r a t i o n or active medical treatment. 3 Does such a policy lead, as many have claimed, to perforation of the a p p e n d i x going undetected? It has now b e e n in use for 25 years, and in 5 reports on 942 adults and children with suspected AA, ~8 67 (7%) had a negative appendicectomy, a n d there was 1 d e a t h in a child admitted with advanced peritonitis. In the 4 reports that r e c o r d e d p e r f o r a t i o n rates, ~6 402 acutely i n f l a m e d appendices were removed, of which 87 (21%) were perforated. O f these, 80 were r e m o v e d at the time of admission; 2 r e q u i r e d resuscitation before operation; and, in 5, o p e r a t i o n b e c a m e indicated after observation. All m a d e a g o o d recovery. E x p e r i e n c e in A b e r d e e n over the years has proved the safety of the practice of active observation, and the negative a p p e n d i c e c t o m y rate has fallen to a r o u n d 5%, without mortality or u n d e t e c t e d perforations. It is t h e n reasonable to ask w h e t h e r use o f CT should be c o n f i n e d to the few patients with an u n u s u a l p r e s e n t a t i o n . Most patients with suspected AA are children or y o u n g adults, which are precisely the groups in which to be particularly cautious a b o u t giving a dose of irradiation that may be m o r e than 100 times that of a chest radiograph. 8 T h e e x p e r i e n c e of Weyant et al is that the use of CT did n o t lower the negative a p p e n d i c e t o m y or perforation rates. This is clear evidence of the n e e d to think again about such wide e m p l o y m e n t of so powerful a tool. They also r e m i n d us that " O t h e r factors such as m o r e precise patient selection by clinical criteria may also be improving outcome." Peter F.Jones, MD Emeritus Clinical Professor of Surgery University of Aberdeen 7 Park Road Aberdeen, Scotland AB15 9HR United Kingdom
References 1. Weyant MJ, Eachempati SR, Maluccio MA, et al. Interpretation of computed tomography does not correlate with laboratory or pathologic findings in surgically confirmed acute appendicitis. Surgery 2000;128:145-52. 2. Jones PE Acute abdominal pain in childhood, with special reference to cases not due to acute appendicitis. BMJ 1969;1:284-6. 3. de Dombal FT. The OMGE Abdominal Pain Survey. ScandJ Gastroent 1988;23(Suppl 144):135-42. 4. Jones PE Active observation in management of acute abdominal pain in childhood. BMJ 1976;2:551-3. 5. WhiteJJ, Santillana A, HallerJA. Intensive in-hospital observation: a safe way to decrease unnecessary appendectomy. Am Surg 1975;41:793-8. 6. Thomson HJ, Jones PE Active observation in acute abdominal pain. AmJ Surg 1986;152:522-5. 7. Dolgin SE, Beck RA, Tarner PI. The risk of perforation when children with possible appendicitis are observed in hospital. Surg Gynecol Obstet 1992;175:320-4. 8. O'Donnell B. Abdominal pain in children. Oxford: Blackwell Scientific Publications; 1985. p. 57-9.
Surgery. Volume 129, Number 4
Letters to the Editors
9. Rehani MM, Berry M. Radiation doses in computed tomography. BM]"2000;320:593-4.
11/59/114144 doi: 10.1067/rosy.2001.114144
Reply We are grateful to Dr J o n e s for his kind c o m m e n t s regarding o u r experiences with c o m p u t e d t o m o g r a p h y (CT) for the diagnosis of acute appendicitis (AA). 1 H e has argued that a brief period of observation and serial examinations can accomplish what CT is designed to do; that is, to increase diagnostic accuracy and lower the negative a p p e n d e c t o m y rate. His own institution's negative a p p e n d e c t o m y rate, at 5%, is laudable. Dr J o n e s makes his a r g u m e n t supported by data that are 8 to 15 years old, before CT for AA b e c a m e so popular b e g i n n i n g in the mid 1990s. We agree, and offer in support of his a r g u m e n t several studies published recently. In 1995, T e m p l e et al 2 followed 95 consecutive adults during a 6-month period, 82 of w h o m had AA. T h e most significant factor in w h e t h e r the a p p e n d i x was perforated was a delay in p r e s e n t a t i o n to the E m e r g e n c y D e p a r t m e n t . Not only was an o b s e r v a t i o n p e r i o d safe f r o m that perspective, patients with p e r f o r a t i o n were observed for a significantly s h o r t e r p e r i o d of time. In 1997, Senbanjo "~followed 418 patients prospectively with a tentative diagnosis o f AA. O n e h u n d r e d sixty-seven patients were observed in-hospital, of w h o m 28 eventually h a d an a p p e n d e c t o m y . T h e negative a p p e n d e c t o m y rate was an acceptable 9.7%, and the perforation rate of 19.7% was also within published norms. 4 Also in 1997, Eldar et al 5 reviewed 486 patients to d e t e r m i n e the relations between a delay in presentation or surgeon delay and the extent of AA at operation. T h e delay in presentation was 0.6 days l o n g e r for patients with p e r f o r a t e d AA (P< .001), but there was no difference in delay to operation after p r e s e n t a t i o n , p r o v i d i n g f u r t h e r s u p p o r t for selective observation of equivocal presentations. Two studies published in 2000 also support the concept of skilled observation of equivocal cases of AA. In a provocative retrospective study, C h u n g et al 6 classified delays as either patient-related, a delay in surgical consultation, or surgeon delay to o p e r a t i o n in a consecutive series of 158 patients who u n d e r w e n t operation. A m o n g the 140 patients with c o n f i r m e d appendicitis, the patients' delay was significantly l o n g e r (mean, 17 hours; P < .005) in patients with a d v a n c e d appendicitis, b u t there was also significant additional delay on the part of the e m e r g e n c y physicians (mean, 12 hours), P < .05). 6 In contrast, there was no difference in surgeon delay with respect to the pathology. Andersson et al 7 studied 420 patients with e q u i v o c a l AA at admission a n d 6 h o u r s thereafter, with serial physical examinations, t e m p e r a ture, white blood cell count, and C-reactive protein measurements. A m o n g the 420 patients, 137 were p r o v e d pathologically to have appendicitis. T h e predictive p o w e r of all tested variables i n c r e a s e d over time, as assessed by an area u n d e r the receiver o p e r a t i n g charac-
515
teristic (ROC) curve > 0.8, but was highest for the clinical assessment of the surgeon (ROC area, 0.89). O f interest, the m a g n i t u d e of change of the t e m p e r a t u r e and labo r a t o r y evaluations h a d n o p o w e r to d i s c r i m i n a t e , indicating that it is the surgeon's clinical assessment that is most important. To be precise, Dr J o n e s has m i s q u o t e d us slightly, because the negative a p p e n d e c t o m y rate did decrease d u r i n g o u r study. We could not attribute that r e d u c t i o n to any aspect of the CT scans p e r f o r m e d at o u r institution. However, we did n o t evaluate those scans perf o r m e d in private offices and b r o u g h t to the E m e r g e n c y D e p a r t m e n t when the patient presented. Perhaps those scans are h e l p i n g the patients' primary care physicians make an accurate diagnosis sooner, thereby r e d u c i n g the delay in presentation that is such an i m p o r t a n t factor. Refinements in t e c h n i q u e may improve the accuracy of CT for AA. For now, surgeons must be circumspect, especially when the scan is read as positive but the white b l o o d cell c o u n t is normal, t We support the practice o f serial evaluations, especially if they can be p e r f o r m e d without admitting the patient to the hospital. A r a n d o m ized trial of e x p e r i e n c e d observation by surgeons in a h o l d i n g area versus CT has yet to be p e r f o r m e d and is n e e d e d urgently.
MichaelJ. Weyant,MD Soumitra R. Eachempati, MD Philip S. Barie, MD Department of Surgery The NewYork-Presbyterian Hospital 525 E 68th St Box 206 New York, N Y 10021
References 1. Weyant MJ, Eachempati SR, Maluccio MA, et al. Interpretation of computed tomography does not correlate with laboratory and pathologic findings in surgically confirmed acute appendicitis. Surgery 2000;128:145-52. 2. Temple CL, Huchcrof SA, Temple WJ. The natural history of appendicitis in adults. Ann Surg 1995; 221:278-81. 3. Senbanjo RO. Management of patients with equivocal signs of appendicitis. J R Coll Surg Edinb 1997,42:85-8. 4. Komer H, Sondenaa K, SoreideJA, et al. Incidence of acute non-perforated appendicitis: age-specific and sex-specific analysis. WorldJ Surg 1997;21:313-7. 5. Eldar S, Nash E, Sabo E, et al. Delay of surgery in acute appendicitis. AmJ Surg 1997;173:194-8. 6. Chung CH, Ng CP, Lai KK. Delays by patients, emergency physicians, and surgeons in the management of acute appendicitis: retrospective study. Hong Kong Med J 2000;6: 254-9. 7. Andersson RE, Hugander A, Ravn H, et al. Repeated clinical and laboratory examinations in patients with an equivocal diagnosis of appendicitis. WorldJ Surg 2000; 24:479-85. 11/59/114143 doi: 10.1067/msy.2001.114143
Letters to the Editors
Surgery April 2001
tion). Clinical scenarios that may predispose to obstruction obviously include previous intra-abdominal o p e r a t i o n (even as minimal as a distant appendectomy), especially after abdominal radiation therapy. Conversely, the astute surgeon will n o t exclude laparoscopic e x a m i n a t i o n of selected patients without an apparent predisposing cause of adhesions (eg, prior celiotomy) if there is suggestive evidence of obstruction--these patients may benefit most by the findings of internal hernias, clinically occult abdominal wall hernias, or even early malignancies. While l a p a r o s c o p i c e x p l o r a t i o n a n d adhesiolysis is p r o b a b l y the least invasive arrow in o u r t h e r a p e u t i c quiver, this consideration does not justify its indiscriminate use in patients with c h r o n i c a b d o m i n a l pain. We especially question its use in patients with u n e x p l a i n e d diffuse, n o n c r a m p y constant pain. T h e basic premise is that l a p a r o s c o p i c e x p l o r a t i o n s h o u l d be o f f e r e d to patients with s o m e convincing evidence o f visceral pain secondary to intestinal obstruction and not a b d o m i n a l wall (somatic) pain. Michael G. Sa~ MD Andrew L. Warshaw, MD References 1. Luque-de Le6n E, Metzger A, Tsiotos GG, Schlinkert RT, Sarr MG. Laparoscopic management of small bowel obstruction: indications and outcome. J Gastrointest Surg 1998;2:132-40. 2. Frank JW, Sarr MG, Camilleri M. Use of gastroduodenal manometry to differentiate mechanical and functional intestinal obstruction: an analysis of clinical outcome. Am J Gastroenterol 1994;89:339-44.
11/59/114220 doi: 10.1067/msy.2001.114220
Computed tomography in suspected acute appendicitis To the Editors: Weyant and his colleagues have m a d e a valuable contribution to the debate over the use of c o m p u t e d tomography (CT) in patients with suspected acute appendicitis. 1 In j u d g i n g the appropriate use of CT, it is useful to look at results in regimes that have n o t e m p l o y e d it. Thirty years ago, the m a n a g e m e n t o f these patients was clarified w h e n it was established that less than half r e q u i r e d an o p e r a t i o n and were o u t n u m b e r e d by a g r o u p whose complaints, t h o u g h at first suspicious of acute appendicitis (AA), settled without t r e a t m e n t over 24 to 48 hoursfl This syndrome was n a m e d Acute Nonspecific A b d o m i n a l Pain, or NSAP, and subsequent surveys t h r o u g h o u t the world c o n f i r m e d this observation in adults and children. 2 T h e s e facts necessarily have an effect o n m a n a g e ment. Patients who have clear signs o f AA or o t h e r acute pathology are, as usual, p r e p a r e d for operation. In those whose signs are m o r e doubtful, a formal policy of 3 to 4 hourly reviews (active observation) is c o m m e n c e d to separate those who steadily improve (and can be discharged with the label of NSAP) from those who, over time, devel-
op m o r e c o n v i n c i n g e v i d e n c e of disease a n d r e q u i r e either o p e r a t i o n or active medical treatment. 3 Does such a policy lead, as many have claimed, to perforation of the a p p e n d i x going undetected? It has now b e e n in use for 25 years, and in 5 reports on 942 adults and children with suspected AA, ~8 67 (7%) had a negative appendicectomy, a n d there was 1 d e a t h in a child admitted with advanced peritonitis. In the 4 reports that r e c o r d e d p e r f o r a t i o n rates, ~6 402 acutely i n f l a m e d appendices were removed, of which 87 (21%) were perforated. O f these, 80 were r e m o v e d at the time of admission; 2 r e q u i r e d resuscitation before operation; and, in 5, o p e r a t i o n b e c a m e indicated after observation. All m a d e a g o o d recovery. E x p e r i e n c e in A b e r d e e n over the years has proved the safety of the practice of active observation, and the negative a p p e n d i c e c t o m y rate has fallen to a r o u n d 5%, without mortality or u n d e t e c t e d perforations. It is t h e n reasonable to ask w h e t h e r use o f CT should be c o n f i n e d to the few patients with an u n u s u a l p r e s e n t a t i o n . Most patients with suspected AA are children or y o u n g adults, which are precisely the groups in which to be particularly cautious a b o u t giving a dose of irradiation that may be m o r e than 100 times that of a chest radiograph. 8 T h e e x p e r i e n c e of Weyant et al is that the use of CT did n o t lower the negative a p p e n d i c e t o m y or perforation rates. This is clear evidence of the n e e d to think again about such wide e m p l o y m e n t of so powerful a tool. They also r e m i n d us that " O t h e r factors such as m o r e precise patient selection by clinical criteria may also be improving outcome." Peter F.Jones, MD Emeritus Clinical Professor of Surgery University of Aberdeen 7 Park Road Aberdeen, Scotland AB15 9HR United Kingdom
References 1. Weyant MJ, Eachempati SR, Maluccio MA, et al. Interpretation of computed tomography does not correlate with laboratory or pathologic findings in surgically confirmed acute appendicitis. Surgery 2000;128:145-52. 2. Jones PE Acute abdominal pain in childhood, with special reference to cases not due to acute appendicitis. BMJ 1969;1:284-6. 3. de Dombal FT. The OMGE Abdominal Pain Survey. ScandJ Gastroent 1988;23(Suppl 144):135-42. 4. Jones PE Active observation in management of acute abdominal pain in childhood. BMJ 1976;2:551-3. 5. WhiteJJ, Santillana A, HallerJA. Intensive in-hospital observation: a safe way to decrease unnecessary appendectomy. Am Surg 1975;41:793-8. 6. Thomson HJ, Jones PE Active observation in acute abdominal pain. AmJ Surg 1986;152:522-5. 7. Dolgin SE, Beck RA, Tarner PI. The risk of perforation when children with possible appendicitis are observed in hospital. Surg Gynecol Obstet 1992;175:320-4. 8. O'Donnell B. Abdominal pain in children. Oxford: Blackwell Scientific Publications; 1985. p. 57-9.
Surgery. Volume 129, Number 4
Letters to the Editors
9. Rehani MM, Berry M. Radiation doses in computed tomography. BM]"2000;320:593-4.
11/59/114144 doi: 10.1067/rosy.2001.114144
Reply We are grateful to Dr J o n e s for his kind c o m m e n t s regarding o u r experiences with c o m p u t e d t o m o g r a p h y (CT) for the diagnosis of acute appendicitis (AA). 1 H e has argued that a brief period of observation and serial examinations can accomplish what CT is designed to do; that is, to increase diagnostic accuracy and lower the negative a p p e n d e c t o m y rate. His own institution's negative a p p e n d e c t o m y rate, at 5%, is laudable. Dr J o n e s makes his a r g u m e n t supported by data that are 8 to 15 years old, before CT for AA b e c a m e so popular b e g i n n i n g in the mid 1990s. We agree, and offer in support of his a r g u m e n t several studies published recently. In 1995, T e m p l e et al 2 followed 95 consecutive adults during a 6-month period, 82 of w h o m had AA. T h e most significant factor in w h e t h e r the a p p e n d i x was perforated was a delay in p r e s e n t a t i o n to the E m e r g e n c y D e p a r t m e n t . Not only was an o b s e r v a t i o n p e r i o d safe f r o m that perspective, patients with p e r f o r a t i o n were observed for a significantly s h o r t e r p e r i o d of time. In 1997, Senbanjo "~followed 418 patients prospectively with a tentative diagnosis o f AA. O n e h u n d r e d sixty-seven patients were observed in-hospital, of w h o m 28 eventually h a d an a p p e n d e c t o m y . T h e negative a p p e n d e c t o m y rate was an acceptable 9.7%, and the perforation rate of 19.7% was also within published norms. 4 Also in 1997, Eldar et al 5 reviewed 486 patients to d e t e r m i n e the relations between a delay in presentation or surgeon delay and the extent of AA at operation. T h e delay in presentation was 0.6 days l o n g e r for patients with p e r f o r a t e d AA (P< .001), but there was no difference in delay to operation after p r e s e n t a t i o n , p r o v i d i n g f u r t h e r s u p p o r t for selective observation of equivocal presentations. Two studies published in 2000 also support the concept of skilled observation of equivocal cases of AA. In a provocative retrospective study, C h u n g et al 6 classified delays as either patient-related, a delay in surgical consultation, or surgeon delay to o p e r a t i o n in a consecutive series of 158 patients who u n d e r w e n t operation. A m o n g the 140 patients with c o n f i r m e d appendicitis, the patients' delay was significantly l o n g e r (mean, 17 hours; P < .005) in patients with a d v a n c e d appendicitis, b u t there was also significant additional delay on the part of the e m e r g e n c y physicians (mean, 12 hours), P < .05). 6 In contrast, there was no difference in surgeon delay with respect to the pathology. Andersson et al 7 studied 420 patients with e q u i v o c a l AA at admission a n d 6 h o u r s thereafter, with serial physical examinations, t e m p e r a ture, white blood cell count, and C-reactive protein measurements. A m o n g the 420 patients, 137 were p r o v e d pathologically to have appendicitis. T h e predictive p o w e r of all tested variables i n c r e a s e d over time, as assessed by an area u n d e r the receiver o p e r a t i n g charac-
515
teristic (ROC) curve > 0.8, but was highest for the clinical assessment of the surgeon (ROC area, 0.89). O f interest, the m a g n i t u d e of change of the t e m p e r a t u r e and labo r a t o r y evaluations h a d n o p o w e r to d i s c r i m i n a t e , indicating that it is the surgeon's clinical assessment that is most important. To be precise, Dr J o n e s has m i s q u o t e d us slightly, because the negative a p p e n d e c t o m y rate did decrease d u r i n g o u r study. We could not attribute that r e d u c t i o n to any aspect of the CT scans p e r f o r m e d at o u r institution. However, we did n o t evaluate those scans perf o r m e d in private offices and b r o u g h t to the E m e r g e n c y D e p a r t m e n t when the patient presented. Perhaps those scans are h e l p i n g the patients' primary care physicians make an accurate diagnosis sooner, thereby r e d u c i n g the delay in presentation that is such an i m p o r t a n t factor. Refinements in t e c h n i q u e may improve the accuracy of CT for AA. For now, surgeons must be circumspect, especially when the scan is read as positive but the white b l o o d cell c o u n t is normal, t We support the practice o f serial evaluations, especially if they can be p e r f o r m e d without admitting the patient to the hospital. A r a n d o m ized trial of e x p e r i e n c e d observation by surgeons in a h o l d i n g area versus CT has yet to be p e r f o r m e d and is n e e d e d urgently.
MichaelJ. Weyant,MD Soumitra R. Eachempati, MD Philip S. Barie, MD Department of Surgery The NewYork-Presbyterian Hospital 525 E 68th St Box 206 New York, N Y 10021
References 1. Weyant MJ, Eachempati SR, Maluccio MA, et al. Interpretation of computed tomography does not correlate with laboratory and pathologic findings in surgically confirmed acute appendicitis. Surgery 2000;128:145-52. 2. Temple CL, Huchcrof SA, Temple WJ. The natural history of appendicitis in adults. Ann Surg 1995; 221:278-81. 3. Senbanjo RO. Management of patients with equivocal signs of appendicitis. J R Coll Surg Edinb 1997,42:85-8. 4. Komer H, Sondenaa K, SoreideJA, et al. Incidence of acute non-perforated appendicitis: age-specific and sex-specific analysis. WorldJ Surg 1997;21:313-7. 5. Eldar S, Nash E, Sabo E, et al. Delay of surgery in acute appendicitis. AmJ Surg 1997;173:194-8. 6. Chung CH, Ng CP, Lai KK. Delays by patients, emergency physicians, and surgeons in the management of acute appendicitis: retrospective study. Hong Kong Med J 2000;6: 254-9. 7. Andersson RE, Hugander A, Ravn H, et al. Repeated clinical and laboratory examinations in patients with an equivocal diagnosis of appendicitis. WorldJ Surg 2000; 24:479-85. 11/59/114143 doi: 10.1067/msy.2001.114143