Br. J. Surg. Vol. 66 (1979) 398-403

Acute pancreatitis in Hong Kong G. B. ONG, K . H. L A M , S . K. L A M , T. K. L I M A N D J O H N WONG' SUMMARY

80A series of 311 Chinese patients with acute pancreatitis admitted to Queen Mary Hospital, Hong Kong, over a 70 10-year period is reviewed. Biliary tract disease was associated with pancreatitis in 52.4 per cent of patients 60 and 77.9 per cent of them had stones, mud or parasites I I L in the common bile duct. Fever andjaundice werepresent in 55per cent and 41-2 per cent of patients respectively. g 50Because of the prevalence of recurrent pyogenic .-uu cholangitis among the indigenouspopulation, emergency 40operation, with the aim of common duct decompression, was conducted in 54.3 per cent of patients during the 30acute episode, with a mortality rate of 14.8 per cent. Five of 142 patients (3.5 per cent) died whilst on 20 conservative treatment and all 5 had haemorrhagic pancreatitis. The overall mortality rate was 9 6 p e r cent. 10Exploration of the common bile duct, which was carried out in 57.4 per cent of patients in the acute phase, was not associated with a higher mortality than when laparotomy alone was performed, and 19 patients had Age (rr) sphincteroplasty without any death. Subtotal pancrea- Fig. 1. Age and mortality of cases of acute pancreatitis. tectomy was performed in 2 patients with haemorrhagic pancreatitis with I death. 31 I patients

-

L

MORTALITY rates of acute pancreatitis reported from different countries vary quite widely. These variations have been attributed to associated aetiological factors in different proportions as well as to different racial compositions (Albo et al., 1963; Marks and Banks, 1963; Mayday and Pheils, 1970; Imrie, 1974; Olsen, 1974). However, even in the same country, mortality rates have varied depending on whether the study was carried out prospectively or retrospectively (Trapnell and Anderson, 1967; Imrie, 1974; Trapnell et al., 1974; Imrie and Whyte, 1975). Furthermore, the mortality rate associated with operations in the acute phase has been claimed to be prohibitively high (Imrie, 1974), or not different from that associated with conservative treatment (Trapnell and Anderson, 1967; Trapnell, 1974). In Hong Kong, where biliary tract disease is common among the indigenous Chinese population, it has been our practice to perform an early operation on patients with acute pancreatitis. We present here the results of a retrospective study of 311 cases of acute pancreatitis with particular reference to the associated aetiological factors and the results of early surgical intervention. Patients and methods Patients Over a 10-year period from 1967 to 1976 311 patients with acute pancreatitis were admitted to the University Surgical Unit, Queen Mary Hospital, Hong Kong. There were 123 males and 188 females. Age incidence is shown in Fig. 1 and the range was 7-86 years with a mean of 47.6 years. Diagnosric criteria: Patients who presented with a clinical history consistent with acute pancreatitis and confirmed by the finding of a serum amylase of 1000 Somogyi units o r more, o r urinary diastase of 60 Wohlgemuth units o r more were included in this study. Patients with operative o r post-mortem findings of acute pancreatitis were also included.

I

I

Conservative 245

Operative 66

No operation

Elective operation

Emergency operation

81

56

I69

Total operation 215

I

I

Deaths 30

Fig. 2. Summary of treatment and results.

Biliary disease was accepted as an associated factor when confirmation was obtained at operation o r at post-mortem examination, or when radiological investigations a t least 6 weeks after an acute episode demonstrated stones in the biliary system. All patients successfully treated without operation were investigated radiologically for biliary tract disease with oral cholecystography and intravenous cholangiography. Patients who drank more than 300ml of spirits daily for more than 10 years and who suffered from an attack within 36 h of the last bout of drinking were regarded as suffering from alcoholic pancreatitis. Shock was diagnosed when the blood pressure dropped to 80 mmHg or below a t any stage of the acute attack before o r after the institution of conservative therapy. Respiratory failure was diagnosed in any patient who had tachypnoea in spite of oxygen therapy and who showed radiological evidence of diffuse infiltration in both lung fields; o r

* Department of Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong. Correspondence t o John Wong.

Acute pancreatitis in Hong Kong when arterial oxygen estimations showed a level of 70 mmHg or less. Renal failure was present when a rise in blood urea of over 20 SI units failed to respond to adequate fluid replacement. Ileus was present when nasogastric aspiration yielded 500 ml or more per day for 5 days or more and when there was no clinical or radiological evidence of mechanical obstruction. Haemorrhagic pancreatitis was diagnosed only at operation or post-mortem examination when there was gross retroperitoneal haemorrhage, usually in association with bloody intraperitoneal fluid and fat necrosis. Microscopic evidence of haemorrhage alone was not included. Associated aetiological factors: The commonest associated condition was biliary tract disease (Table I).This accounted for 163 (524 per cent) of our patients and 127 (77.9 per cent) had stones, mud or parasites in the common bile duct. Alcoholism was associated in 15.1 per cent and trauma in 7.4 per cent of patients. In 75 patients (24.1 per cent) no associated factors were evident. Number of attacks on presentation: This presentation represented a first attack in 73.2 per cent of the patients, a second attack in 12.1 per cent, a third attack in 4.8 per cent and 3.9 per cent presented in their sixth or more attack, the maximum being a fourteenth attack in one patient. Clinical features: Pain was the universal symptom. Fever and jaundice were present in 55 and 41.2 per cent respectively and 10.6 per cent of patients presented in or developed shock in the course of their acute attack. Peritonitis was present in 29-6 per cent and an abdominal mass was found in 5.1 pel cent. Plain X-ray of abdomen: This investigation was of little value in the diagnosis of acute pancreatitis. Gallstones were seen in 4.2 per cent, a sentinel loop in 2.6 per cent and gas in the biliary tree in 0.6 per cent. Treatment Managemenf of acute attack: Initial management included nasogastric aspiration, intravenous fluid replacement, analgesics (usually pethidine) and antibiotics (usually ampicillin). Atropine and Trasylol were given to 22 and 9 patients respectively in the past, but these two drugs were not used in recent years. Patients in shock were monitored by measurement of central venous pressure, hourly urinary output and regular estimations of arterial gases. Plasma infusion and, occasionally, blood were given until blood pressure and urinary output were satisfactory. Patients who were jaundiced, in shock, or had signs of peritonitis or in whom other diagnoses (particularly recurrent pyogenic cholangitis) were suspected were operated on after initial resuscitative treatment. Since recurrent pyogenic cholangitis may be associated with shock from septicaemia, or peritonitis without clinical jaundice, patients in shock or who had peritonitis during their acute attack were invariably explored, even though the diagnosis of acute pancreatitis was established biochemically. Thus the suspicion of cholangitis either as the primary or an additional diagnosis was the indication for the vast majority of emergency operations. Conservative treatment was deemed to have failed in patients who continued to have severe symptoms or became shocked, or developed signs of peritonitis or jaundice. These patients were also subjected to emergency operations. Emergency operations were performed on 66 patients (21.2 per cent) soon after admission (Fig. 2). Conservative treatment on the remaining 245 patients was successful in 137 (55.9 per cent). One hundred and three patients (42 per cent) failed to respond to conservative treatment and underwent emergency operations up to 10 days after admission. In all, 169 patients (54.3 per cent) were operated on during the course of their acute attack. The indications for operation are shown in Table II. Of the 137 patients successfully managed conservatively, elective operations were performed in 56 (40.9 per cent) because of radiologically demonstrated biliary tract disease (51 patients), or because of development of pancreatic pseudocyst (5 patients). Five patients who had biliary tract disease initially refused operation but because of recurrent attacks

399

Table I: ASSOCIATED AETIOLOGICAL FACTORS

No. of vatients Biliary tract disease Gallstones RPC Gallstones+RPC Alcoholism Traumatic Postoperative complication External injury Pregnancy and post-partum Idiopathic Total

50 (16.0) 47 ( 15.1) 23 (7.4) 16 (5.1) 7 (2.3) 3 (1.0) 75 (24.1) 311 (100.0)

RPC, Recurrent pyogenic cholangitis. Figures in parentheses are percentages. Table 21: INDICATIONS FOR EMERGENCY OPERATION Generalized peritonitis and uncertain diagnosis* Jaundice with peritonitis Shock with peritonitis Persistent pain Epigastric mass Total

No.

%

64

37.9

40 33 27 5 169

23.7 19.5 160 2.9 100.0

* Many suspected to have recurrent pyogenic cholangitis. Table 111: OPERATIONS PERFORMED IN ACUTE ATTACK AND MORTALITY No. X Died MR* Laparotomy Alone With biopsy of omentum With biopsy of pancreas With drainage of pancreatic bed Exploration of common bik duct Alone With cholecystectomy With cholecystectomy and sphincteroplasty With cholecystostomy With sphincteroplasty Cholecystectomy Cholecystostomy Sphincteroplasty Pancreatectomy Gastrocystostomy Total

55

32.5

19 16 6 14

8

14.5

14

14.9

3 2 0 3 97

57.4

47 31 I0

11 2 0

4

1 0

5

4 2 4 4 3 169 100.0

0

1 0 2 0

25

14.8

* Mortality rate of procedure. subsequently underwent surgery. Eighty-one patients (59.1 per cent) were not operated on. Thus, in total, 225 patients (72.3 per cent) underwent operative treatment either as an emergency or elective procedure. At operation during the acute attack the pancreas was found to be oedematous in 115 patients (68 per cent), there was haemorrhage in 25 and in 29 patients the gland showed localized necrosis with abscess formation. In 109 of these 169 patients (64.5 per cent) biliary tract disease was present. Operations performed during acute attack: The procedures carried out and the mortality associated with each procedure are shown in Table III. Laparotomy alone or with biopsy or with drainage of the pancreatic bed was performed in 325 per cent of patients. Biliary tract operations were performed in all the remainder except 7. The commonest biliary operation was exploration of the common bile duct (574 per cent) with or

400

G. B. Ong et al.

Table IV: PANCREATECTOMY IN ACUTE PANCREATITIS Operation Aetiological Result performed Sex/Age factor Pathology found Died on Distal M/50 Postoperative Oedematous day 2 pancreatectom y pancreatitis with abscess 5 yr Alive Partial F/52 Idiopathic Oedematous pancreatectomy pancreatitis with pseudocyst Died on Subtotal F/67 Idiopathic Haemorrhagic day 17 pancreatectomy pancreatitis M/61

Biliary

Subtotal pancreatectomy

Haemorrhagic pancreatitis

Table V: COMPLICATIONS OF THE DISEASE

%

No. 81 33

Ileus Shock Septicaemia Pancreatic abscess Hypocalcaemia with tetany Pancreatic pseudocyst Gastrointestinal bleeding

26.0 106 6.1 4.2 2.6 1.6 0.6

19 13 8 5 2

Table VI: NON-FATAL POSTOPERATIVE COMPLICATIONS No. 9 Wound infection Subphrenic abscess 8 8 Residual ductal stone Chest infection 5 4 Discharging sinus 2 Gastrointestinal bleeding 2 Renal failure Intestinal fistula 1 1 Burst abdomen

%

5.3 4.1 4.1 2.9 2.4 1.2 1.2 0.6 0.6

Table VII: CAUSES OF DEATH IN THE OPERATED GROUP

No. 16 14 14 13 11

Septicaemia Peritonitis Respiratory failure Shock Renal failure Subphrenic abscess Gastrointestinal bleeding Intestinal fistula Myocardial infarction

6 2 1 1

% 9.5 8.3 8.3 7.7 6.5 3.5 1.2 0.6 0.6

Table VIII: DEATHS AND ASSOCIATED AETIOLOGICAL FACTORS

Biliary Gallstones RPC Gallstones+ RPC Alcoholic Traumatic Pregnancy and post-partum Idiopathic Total

Overall incidence

No.of deaths

%of total

18

600

52.4

I

234 3.3 3.3 10.0 100.0

15.1

(%)

3 10 5 1 1

3 30

RPC, Recurrent pyogenic cholangitis.

14 1 .o 24.1

Alive 2 yr

Complication

Cause of death

Massive gastrointestinal bleeding

Sepsis and gastrointestinal bleeding

Nil

-

Gastric fistula, diabetes, Sepsis, hypocalcaemia, respiratory respiratory failure failure Persistent sinus for 3 mth, diabetes

without an added procedure. Sphincteroplasty was carried out in 19 patients (11.2 per cent). Four patients had pancreatectomies and their clinical summaries are shown in Table IV.

Results Complications of the disease and operations The complications of the disease are shown in Table V. Since over half (54.3 per cent) of our patients were operated on during the acute attack, this Table represents complications that were present on admission or which developed in the course of nonoperative treatment. Since the non-operated group was selected on the basis of a clinically mild attack, a relatively low incidence of complications may therefore be expected. Non-fatal postoperative complications are shown in Table VI. Some of these complications may be the result of the disease rather than of the operation, and the incidence of complications of the disease may well have been greater if fewer patients had undergone operation. Respiratory failure occurred in 19 patients and was a significant factor in the death of 14. Renal failure was present in 13 patients and was a contributory cause of death in 11. Mortality rates There were 30 deaths (9.6 per cent) in this series. In the group operated on during the acute attack, the mortality rate was 25 out of 169 (14.8 per cent). In the non-operated group, it was 5 out of 142 (3.5 per cent). In the operated group, those who underwent exploration of the common bile duct did not suffer a higher mortality than those who had exploratory laparotomy alone (Table IIZ), and 19 patients had sphincteroplasty without a death. Two of 4 patients who had a pancreatectomy died. The causes of death in the operated group are shown in Table VZZ. The deaths tabulated according to aetiological factors and compared with the overall incidence of each aetiological factor are shown in Table VIZZ. The mean age of the 30 patients who died was 59 years, which was 11.4 years more than the mean age for the whole series. Only 4 deaths occurred in the under-50 age group (2.4 per cent). In the over-50 age group the mortality rate was 26 out of 144 (18.1 per cent). At operation or post-mortem, the pancreas in the 30 cases who died was seen to be haemorrhagic in 23, showing localized necrosis with abscess in 3 and an oedematous gland in 4. Conversely, when an oedematous pancreas was found at operation the mortality was 4 out of 115 (3.5 per cent), which is the same as in the conservatively treated group. However, when localized necrosis with abscess formation was present

Acute pancreatitis in Hong Kong

401

Table IX: MORTALITY OF OPERATIVE AND NON-OPERATIVE MANAGEMENT IN FOUR SERIES Bristol (1950-61)* Glasgow (1960-70)f Glasgow (1971-2)$ Hong Kong (1967-76)t Deaths Deaths Deaths Deaths Treatrnent n % n n % n n % n n n % 25 14.8 11 5 45.5 169 91 41 15 36.6 21 23.1 Operative Non-operative 233 55 23.6 86 9 10.5 67 4 6.0 142 5 3.5 78 9 11.5 311 30 9.6 127 24 18.9 Overall result 324 76 23.4

. .

* Trapnell and Anderson (1967);

f Irnrie (1974);

$. Imrie and Whyte (1975);

the mortality rose t o 3 out of 29 (10.3 per cent), and in those with haemorrhagic pancreatitis the mortality was 72 per cent. The mortality rates of operative and non-operative management in this series are compared with those in three British series in Table IX. Acute haemorrhagic pancreatitis Although the exact incidence of this more severe form of pancreatitis in any reported series is unknown (but estimated to be between 10 and 25 per cent; Glazer, 1975), the mortality rate of haemorrhagic pancreatitis, when diagnosed at operation, was very high. In 169 emergency operations during the acute attack, 25 cases of haemorrhagic pancreatitis were found and 18 of them subsequently died (72 per cent). The 5 deaths in the conservatively treated group were all found to have haemorrhagic pancreatitis at postmortem. Subtotal pancreatectomy was performed in 2 patients with 1 death. Late results Of the 311 patients in this series, 107 were not available for follow-up study (30 died in the acute episode, 9 died from other causes after discharge from hospital and 68 defaulted follow-up). Of the remaining 204 patients, 199 (92.6 per cent) were symptom-free and 15 (7.4 per cent) had further attacks. Six of these 15 had biliary tract diseases demonstrated but refused surgery. Five subsequently were operated on and were free of further symptoms. Two patients had attacks after biliary tract surgery but have now been without symptoms for 3 and 8 years respectively. Seven patients had no biliary tract diseases but suffered recurrent attacks; 4 of these 7 patients had biliary surgery without arrest of subsequent attacks.

Discussion Associated aetiological factors The incidences of associated aetiological factors in our series are almost identical to those reported in recent British series (Imrie, 1974; Trapnell, 1974), but contrast significantly with American, Australian and South African series (Marks and Banks, 1963; Barraclough and Coupland, 1972; Olsen, 1974) where alcohol was demonstrated to be the cause in half or more of the patients with acute pancreatitis. Biliary tract disease was shown to be the most commonly associated condition in our series (52.4 per cent), although this proved not to be as high as we had previously suspected. Our incidence of unknown causes is high, and is a feature of a retrospective study (Imrie, 1974) as compared with a prospective one (Imrie and Whyte, 1975). Quite likely, more patients in the idiopathic group would be classified as alcoholics if a more searching history was obtained, and the incidence of biliary tract disease would be higher if more refined investigations were performed

5 Present series.

on patients who recovered from conservative treatment. Only one patient with alcoholic pancreatitis had gallstones, a rare association, also shown by Barraclough and Coupland (1972) though denied by Mayday and Pheils (1970) and Olsen (1974). In our series, the incidence of ductal stones in patients with biliary tract disease was 77-9 per cent, which was much higher than that reported by Barraclough and Coupland (1972) (11.1 per cent) and by Imrie (1974) (20 per cent). This is reflected in the presentation of a large number of our patients with fever and jaundice from cholangitis. This high incidence of ductal stones encouraged us to operate early in patients with suspected biliary tract disease. Since ductal stones may pass through the ampulla (Acosta and Ledesma, 1974), and in some cases possibly after initiating an attack of pancreatitis, the incidence of ductal stones in reported series is probably underestimated. Furthermore, as radiological diagnosis of biliary tract disease may have false negative results, the true incidence of biliary tract disease may be even higher. Mortality rate Mortalitv rates reDorted in British series with similar incidences of aetiological factors have been higher than ours: Trapnell and Anderson (1967), 23.4 per cent; Imrie (1974), 18.9 per cent; present series, 9.8 per cent. However, a recent prospective study by Imrie and Whyte (1975) showed that there is a decline in mortality rates (to 11.5 per cent), and the reasons for this have been attributed by the authors t o a lower incidence of diagnosis by laparotomy than in the retrospective studies, earlier diagnosis because of clinical awareness, improved methods of serum and urine amylase estimations, an appreciation of the risk from operations and improved care from personal interest in the condition. Since these factors are not features of our retrospective study, it must be concluded that our low mortality rate reflected a different natural history of the disease in our Chinese patients. Similar low mortality rates have been reported by Albo et al. (1963) (11 per cent), Louw et al. (1967) (12 per cent) and Olsen (1974) (6 per cent), where the incidence of alcoholic pancreatitis was high. Mortality associated with operation in the acute phase of pancreatitis varies greatly in different reports. Those in favour of early operation (Trapnell, 1966; Louw et al., 1967; Kune, 1968; Diaco et al., 1969; Barraclough and Coupland, 1972) claimed that there was no added risk when laparotomy and simple remedial surgery were carried out. On the other hand, Imrie (1974) and Imrie and Whyte (1975), in both retrospective and prospective studies, have shown the mortality rate of operation t o be 33 and 74 times respectively that of conservative treatment. Our series also demonstrated a greater than fourfold increase in mortality rate associated with operation.

402

G. B. Ong et al.

This high mortality is related to the many patients in our series who were operated on in shock and with cholangitis, which gave rise to deaths from infections and respiratory and renal failure. The high mortality rate associated with acute haemorrhagic pancreatitis is reflected in our series. Since the true incidence of haemorrhagic pancreatitis in any series of acute pancreatitis is not known, reported mortality rates of between 40 per cent and 82 per cent (Kaplan et al., 1964; Kune, 1968; Nugent and Zuberi, 1968; Jordan and Spjut, 1972) are only approximations. Of the 30 deaths in our series, 23 (76.7 per cent) had haemorrhagic pancreatitis. Since we had operated on about half of our patients during the acute attack (and operation was performed on those with severe disease), and since the incidence of operative diagnosis of haemorrhagic pancreatitis was only 14.8 per cent, it would appear that in our community the incidence of haemorrhagic pancreatitis is unlikely to exceed 10-15 per cent, which is within the range of 10-25 per cent estimated by Glazer (1975). Operative management We operated on 54.3 per cent of our patients in the acute phase because of the high incidence of biliary tract disease, especially the condition of recurrent pyogenic cholangitis (Ong, 1968), among the indigenous population. Many of these patients presented with or developed septicaemic shock from cholangitis. In addition, 12.5 per cent of the patients with recurrent pyogenic cholangitis also had pancreatitis. Thus, even when a diagnosis of acute pancreatitis is established biochemically, if there is any suspicion of cholangitis, such as jaundice, fever or chills, early surgical intervention is mandatory. When the serum amylase is not raised and cholangitis is suspected, the need for early operation is even more urgent as all the clinical features may be attributable t o cholangitis. It is also our belief that when acute pancreatitis is associated with ductal stones, decompression of the bile duct may minimize the severity or reverse the progression of the disease. For these reasons, early operation was our choice of treatment unless the disease was clinically mild, there was a strong probability that alcohol was the cause or biliary tract disease could reasonably be excluded. Common duct exploration was the procedure most frequently performed (57.4 per cent) and the mortality of this procedure did not differ from that of laparotomy alone. Although we were reluctant to perform sphincteroplasty in the acute phase because of the many recognized hazards (Anderson, 1965; Louw et al., 1967; Trapnell, 1972), this operation was carried out in 19 patients without complications or deaths. In each instance a stone was impacted at the ampulla, and we believe, as do Salzman and Bartlett (1963), that under these circumstances this operation is essential and can be performed without added risk t o the patient. Pancreatectomy for acute haemorrhagic pancreatitis has been advocated by Watts (1963), Hollender et al. (1969) and Guivarch et at. (1972). Although this is a severe operation in a critically ill patient, removal of the necrotic gland may offer these patients a small chance of recovery since the mortality of other forms of treatment is equally prohibitive. The rapid clinical improvement of the one patient in this series who survived subtotal pancreatectomy may indicate that

in selected patients this course of treatment may be the appropriate one. Our mortality rate in the operated group of 14.8 per cent is substantially higher than that in the nonoperated group (3.5 per cent). This mortality rate, though lower than that reported by Trapnell (1974) and Imrie (1974), could probably be reduced if some patients without biliary tract diseases were treated conservatively. The total number of patients in our series who underwent operations (emergency and elective) was 225 (72.3 per cent) which is 62 (19.9 per cent) more than the total number of patients with biliary tract disease. If this latter group of patients could be identified, they might have been treated conservatively, so long as there were no other indications for operation. Since the association of biliary tract diseases and alcoholic pancreatitis was rare in our patients, a definite history of alcohol excesses should be accepted as the only cause, and these patients should be treated without operation if the diagnosis can be established biochemically. However, in spite of the large number of operations, the mortality rate is not unduly high. This probably represents the small risk of operation (3.5 per cent mortality) when an oedematous gland is found. We agree with Trapnell’s suggestion (1974) that exploratory laparotomy in acute pancreatitis is not such a lethal procedure as it was once thought. It should be undertaken if the diagnosis is in doubt or if the patient’s condition deteriorates in spite of adequate conservative measures. This principle has also been advocated by Anderson (1965), Zimberg (1968) and Glazer (1975). Our results show that patients with biliary tract disease who refuse surgery almost invariably suffer from further acute attacks. Although biliary tract surgery does not confer absolute immunity from subsequent attacks, the risk of such recurrence appears t o be minimal. On the other hand, biliary tract surgery offers no protection against further attack for alcoholic patients and patients with other or unknown causes.

References and LEDESMA c. L. (1974) Gallstone migration as a cause of acute pancreatitis. N. Engl, J. Med. 2 9 0 , 4 8 4 - 4 8 7 . ALBO R., SILEN w. and GOLDMAN L. (1963) A critical clinical analysis of acute pancreatitis. Arch. Surg. 86, 1032-1038. ANDERSON M. c. (1965) Surgical intervention in acute pancreatitis. Surg. Gynecol. Obstet. 120, 1301-1302. BARRACLOUGH B. H. and COUPLAND G. A. E. (1972) Acute pancreatitis: a review. Aust. N.Z. J. Surg. 41, 211-218. DIACO J. F., HlLLER L. D. and COPELAND E. M. (1969) The role O f early diagnostic laparotomy in acute pancreatitis. Surg. Gynecol. Obstet. 129, 263-269. GLAZER G. (1975) Haemorrhagic and necrotizing pancreatitis. Br. J. Surg. 63, 169-176. GUIVARCH M., BEAUFILS F., NEURY N. et al. (1972) Excisional surgery in necrotic pancreatitis. J. Chirurgie (Paris) 103, 479-492. HOLLENDER L. P., GILLET M., SAVA G. et al. (1969) Acute postoperative pancreatitis: clinical study and plea for more systematic intervention, with early pancreatectomy. J. Chirurgie (Paris) 97, 177-198. IMRIE c. w. (1974) Observation on acute pancreatitis. Er. J . Surg. 61,539-544. IMRIE c. w. and WHYTE A. s. (1975) A prospective study of acute pancreatitis. Br. J . Surg. 63,490494. JORDON G. L. and SPJUT H. J. (1972) Hemorrhagic pancreatitis. Arch. Surg. 104, 489493. ACOSTA J. M.

Acute pancreatitis in Hong Kong and STAGG s. J. (1964) Acute pancreatitis : six-year survey with evaluation of steroid therapy. Am. J. Surg. 108, 24-30. KUNE G. A. (1968) The challenge of severe acute pancreatitis. Med. J. Aust. 2, 8-12. LOUW J. H., MARKS I. N. and BANKS s. (1967) The management of severe acute pancreatitis. Postgrad. Med. J. 43, 31-44. MARKS I. N. and BANKS s. (1963) The etiology, clinical features and diagnosis of pancreatitis in South Western Cape. S. Afr. Med. J. 37, 1039-1056. MAYDAY G. B. and PHEILS M. T. (1970) Pancreatitis: a clinical review. Med. J. Aust. 1, 1142-1144. NUGENT F. w. and ZUBERI s. (1968) Treatment of acute pancreatitis. Surg. Cfin. North Am. 48, 595-599. OLSEN H. (1974) Pancreatitis : a prospective clinical evaluation of 100 cases and review of the literature. Am. J. Dig. Dis. 19, 1077-1090. ONG 0. B. (1968) Recurrent pyogenic cholangitis. In: SCOTT R. B. and WALKER R. M. (ed.) Medical Annual, 86th issue. Bristol, Wright, pp. 25-36.

KAPLAN M. H., COTLAR A. M.

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w. and BARTLETT M. K. (1963) Pancreatic duct exploration in selected cases of acute pancreatitis. Ann. Surg. 158, 859-863. TRAPNELL J. E. (1966) The natural history and prognosis of acute pancreatitis. Ann. R. CON. Surg. Engl. 38, 265-287. TRAPNELL J. E. (1972) The natural history and management of acute pancreatitis. Clin. Gastroenterol. 1, 147-166. TRAPNELL J. E. (1974) Acute pancreatitis in Great Britain-a review. Med. J. Ausr. 2, 450455. TRAPNELL J. E. and ANDERSON M. c. (1967) Role of early laparotomy in acute pancreatitis. Ann. Surg. 165, 49-55. TRAPNELL J. E., RIGBY C . C., TALBOT C. H. et 8.1. (1974) A Controlled trial of Trasylol in the treatment of acute pancreatitis. Br. J. Surg. 61, 177-182. WATTS G. T. (1963) Total pancreatectomy for fulminant pancreatitis. Lancer 2, 384. ZIMBERG Y. H. (1968) Pancreatitis: principles of management. Surg. Clin. North Am. 48, 889-905.

SALZMAN E.

Paper accepted 10 November 1978.

Statistics in The British Journal of Surgery It is part of the clinical scientist’s stock-in-trade t o use statistical methods. In many instances, and by most readers, these can be taken on trust, but in that there is a wide variety of tests and, on occasion, disagreement amongst both amateurs and professionals on the best choice, it is always wise that authors quote the method used. It is indeed journal policy to quote methods, the reason for their choice and, in the case of clinical trials, the confidence or tolerance limits of the observed results. Delay in acceptance may occur if contributors do not include these details.