HIGH SPINAL NERVE BLOCK FOR LARGE BOWEL ANASTOMOSIS A retrospective study

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1 Br.J. Anaesth. (1978), 50, 177 HIGH SPINAL NERVE BLOCK FOR LARGE BOWEL ANASTOMOSIS A retrospective study A. R. AlTKENHEAD, H. Y. WlSHART AND D. A. PEEBLES BROWN SUMMARY In a retrospective study, 68 large bowel anastomoses carried out on patients under subarachnoid or extradural spinal nerve block with light general anaesthesia were compared with 26 anastomoses on patients receiving general anaesthesia alone. Dehiscence occurred in 7.4% of anastomoses performed under spinal nerve block compared with 23.1 % in the control group. In patients receiving morphine, anastomotic dehiscence occurred after 15.2% of operations, compared with 5.9% in patients receiving pethidine. These differences are not statistically significant. However, the findings indicate the need for larger prospective studies. Subarachnoid and extradural spinal nerve block anaesthesia are associated with profound relaxation of skeletal muscle, reduced operative bleeding and a contracted bowel (Lee and Atkinson, 1973). These effects may be beneficial in patients undergoing large bowel anastomosis because: (a) operative access is improved, (b) reduced bleeding permits easier surgery, (c) the anastomic breakdown rate is proportional to blood loss (Whitaker, Dixon and Greatorex, 1970), (d) increased bowel tone may allow easier construction of the anastomosis, and (e) the undesirable effect of neostigmine on the bowel is avoided (Bell and Lewis, 1968; Bell, 1970; Wilkins et al., 1970). In this retrospective study, we have compared the postoperative course in patients undergoing ic or rectal anastomosis constructed under subarachnoid or extradural nerve block, with that in patients receiving general anaesthesia alone. PATIENTS AND METHODS Between 1971 and 1975, subarachnoid block was employed in 46 patients undergoing large bowel anastomosis (group A) and between 1968 and 1971, 30 similar patients received extradural block (group A. R. AlTKENHEAD*, M.B., F.F.A.R.C.S.; H. Y. WlSHART, M.B., F.F.A.R.C.S. ; Department of Anaesthesia, Western Infirmary, Glasgow. D. A. PEEBLES BROWN, M.B., F.R.C.S., Department of Surgery, Western Infirmary and Gartnavel General Hospital, Glasgow. * Present address, University Department of Surgery, Western Infirmary, Glasgow Gil 6NT. B). Between 1968 and 1975, 30 ic or rectal anastomoses were performed under conventional general anaesthesia (group C). All were elective procedures. The case records of 43 patients in group A, 25 in group B and 26 in group C contained sufficient information to allow further analysis. This yielded 94 operations performed on 87 patients. Spinal blocks were performed by one anaesthetist (H. W.) who made no selection of patients for this technique. The patients in group C were anaesthetized by several other anaesthetists. The surgeon did not choose any patient for a particular anaesthetist. Bowel preparation and anastomosis Before operation succinylsulphathiazole 2.5 g was given orally four times daily for 5 days, and neomycin sulphate 1.5 g was administered orally four times daily for 2 days. A bowel washout was performed on the evening before surgery. All anastomoses were performed by the same surgeon (D. P. B.) using the two-layer inverting technique with continuous catgut for the inner layer and interrupted black silk for the outer layer. Anaesthetic technique All patients were premedicated with a narcotic or sedative agent or both, together with hyoscine or atropine. Anaesthesia was induced with i.v. thiopentone, propanidid or Althesin, and the trachea was intubated, usually following the administration of suxamethonium. Groups A and B. Anaesthesia was maintained with halothane 0.5% in 50% nitrous oxide in oxygen, and the patients breathed spontaneously. Spinal nerve

2 178 BRITISH JOURNAL OF ANAESTHESIA block was performed immediately after the induction of anaesthesia, with the patient in the lateral position. In group A, either ml of cinchocaine, 0.5% in 6% dextrose, or ml of amethocaine 1% in an equal volume of 10% glucose, was injected at the level L3-4 or L4-5 into the subarachnoid space using barbotage. In group B, 1.5% lignocaine ml with adrenaline 1 : , or ml of this solution mixed with 0.5% bupivacaine 10 ml with adrenaline 1 : was injected into the extradural space at L3-4. The intention in all instances was to obtain a sensory block to the level T5. The patients were placed supine in a head-down position immediately after performing the block, and for the duration of the operation. Group C. Anaesthesia was maintained with 60-70% nitrous oxide in oxygen supplemented either by the inhalation of halothane or trichloroethylene or by the i.v. injection of morphine or papaveretum, and the lungs were ventilated artificially. Either pancuronium or tubocurarine were given i.v. to produce neuromuscular block, and their effects were antagonized at the end of the procedure by neostigmine 2.5 mg with atropine 1.2 mg i.v. Morphine, papaveretum or pethidine were administered for pain relief after operation. Blood loss was estimated by the weighing of swabs. Arterial pressure was measured in all patients, usually with an oscillotonometer. Detection of anastomotic breakdown The criteria were: (1) escape of flatus and faeces through the wound or drain site or through the vagina (Goligher et al o 1970), (2) anastomotic rupture discovered at laparotomy or postmortem, (3) local abscess formation (Goligher et al., 1970), when subsequent events suggested that anastomotic breakdown had been the cause. Routine postoperative sigmoidoscopy and barium enema were not performed. Other factors Other factors noted were: (1) abdominal distension with signs of intestinal obstruction or persistent vomiting or both, (2) the duration of i.v. fluid administration and the time of commencing oral fluids, (3) the nature of narcotic analgesics given before, during and after operation. Statistical analysis Methods applied were, where appropriate, Student's t test for the significance of the difference between the means of measurements, and the "Fourfold" Table and Chi-squared tests, with Yates' corrections when necessary, for the significance of the differences between proportions of observations. RESULTS Table I lists the types of operation and pathology related to the three groups of patients. The frequency of diverticulitis was significantly greater in group B than in the other two groups. The mean ages were TABLE I. Operations and pathology. Figures in columns show the number of patients, with the percentage of the total (n) in each group in parentheses Operations Resection of terminal ileum and caecum Right hemicolectomy Anastomosis of ileum and transverse Resection of transverse Left hemicolectomy Resection of descending Resection of sigmoid Anterior resection of rectum Rectal polypectomy Pathology Carcinoma Crohn's disease Diverticulitis Rectal polyp Otherf 4 (9.3) 8(18.6) 1 (2.3) 2 (4.7) 5(11.6) 1 (2.3) 10 (23.3) 10 (23.3) 2 (4.7) 28(65.1) 8 (18.6) 2* (4.7) 2 (4.7) 3 (7.0) Anaesthetic group I\ (n = 43) B (n = 25) C (n = 26) 2 (8.0) 7 (28.0) 1 (4.0) 12 (48.0) 3 (12.0) 14 (56.0) 1 (4.0) 10* (40.0) 5 (19.2) 4(15.4) 1 (3.8) 5 (19.2) 2 (7.7) 15 (57.7) 5 (19.2) 0*(0) t One case of tuberculosis. All other cases either inflammatory, or mechanical obstruction. 'Ao.B and C v. B P<0.01. comparable: group A: 63.2 yr (SEM 2.3), group B: 66.1 yr (SEM 2.6), group C: 66.4 yr (SEM 3.4). The mean haemoglobin concentration in group A (12.4 g dl -1 ; SEM 0.3) was significantly less than in group B (13.7±0.4; P<0.01) and group C ( ; P<0.05). The mean duration of the operation was min in group A, min in group B and 63 ± 5 min in

3 SPINAL NERVE BLOCK AND LARGE BOWEL ANASTOMOSIS group C. In group A, the mean maximum decrease in arterial pressure during operation was 58.5% (+1.4) of the value before operation, and the corresponding value in group B was 59.6% (it 2.3). The data on arterial pressure in group C were insufficient to allow comparison with the other groups. The mean blood loss during operation was less in group A ( ml) and group B (42 ± 14 ml) than in group C ( ml) (P<0.01). Eight patients in group C required a blood transfusion during operation, but blood transfusion was not necessary for any patient in groups A or B. After operation, the mean duration of i.v. fluid administration was significantly less in group B (40.3 ± 3.4 h) than in group A ( h) and group C (57.7±4.6 h) (P<0.01). The mean delay before recommencing oral fluids was shorter in group B (27.7 ± 2.4 h) than in group A (33.1 ± 2.2 h) and group C ( h) but these differences were not statistically significant. The occurrence of either paralytic or mechanical ileus before the 4th day, and on or after the 4th day following operation (fig. 1), was more frequent in 179 different and the frequency of wound infection was high in all groups. The mean duration of stay in hospital was days in group A, days in group B and days in group C. There was no significant difference between the groups in this respect. Three patients in group A (7.0%), two in group B (8.0%) and six in group C (23.1%) suffered dehiscence of the anastomosis, but the differences between the groups were not statistically significant (P values: A v. C: 0.05<P<0.1; A + B v. C: 0.05<P<0.1; B v. C: 0.1<P<0.2). Figure 2 shows the frequency of anastomotic breakdown in relation to the administration of Frequency 40-, i! j Morphine I I Pethidine n.22 % Frequency 40-i h-37 E22 Group A (n.43) 30- Group B In. 25) Group C (n.26) 1.34 n-3 All Anoesthettc Groups Groups A*B Group C FIG. 2. Frequency of anastomic breakdown in relation to narcotic analgesics Ileus ot<4days I Ileus at»4days Wound Wound Infection Dehiscence Infected Dram Discharge FIG. 1. Complications after operation. group C (early 19.2%: late 23.1%) than in group A (early 11.6%; late 11.6%) or group B (early 12%; late 4%). The differences were not statistically significant. The frequencies of wound and drain complications in the three groups were not significantly narcotic analgesics before, during and after operation. The frequency of breakdown appeared to be greater in association with the administration of morphine, irrespective of the method of anaesthesia employed, although in patients who received spinal nerve block (groups A and B), the frequency associated with the use of morphine was less than that in the patients in group C who received morphine. However, none of these apparent differences was statistically significant. There was one death in group A, three in group B and three in group C (table II). One death in group B and two in group C were associated with a breakdown of the anastomosis. There were no significant differences between the groups in respect of these data.

4 180 BRITISH JOURNAL OF ANAESTHESIA TABLE II. Mortality Anaesthetic group No. of patients % of group total Cause of death confirmed by postmortem A (n = 43) B (n = 25) C (n = 26) 2.3 Myocardial infarction 17th day 12.0 Myocardial infarction 8 h after operation; infarction was 36 h old Peritonitis following anastomotic breakdown 5th day Bronchopneumonia 19th day 11.5 Massive pulmonary embolism 4th day Haemorrhage from anastomosis and myocardial infarction 2nd day Peritonitis following anastomotic breakdown 20th day No significant differences between groups. Tables III and IV compare the patients who suffered a breakdown of the anastomosis with the remainder of the patients in the study, irrespective of the method of anaesthesia employed. There was no obvious influence of age, haemoglobin concentration, duration of operation, or minimum arterial pressure during operation on the fate of the anas- TABLE III. Nature of operation and pathology in patients tomosis, although, as might be expected, those whose whose anastomosis broke down compared with other patients. anastomosis broke down were later in commencing Figures in columns show the number of patients, with the percentage of the total (n) in each group in parentheses oral fluids and remained longer in hospital. Operation Resection of terminal ileum and caecum Right hemicolectomy Anastomosis of ileum to transverse Resection of transverse Left hemicolectomy Resection of descending Resection of sigmoid Anterior resection of rectum Rectal polypectomy Pathology Carcinoma Crohn's disease Diverticulitis Rectal polyp Other Anastomotic fate Broke down (n=ll) 2 (18.2) 4 (36.4) 7 (63.6) 2 (18.2) Remained intact (n = 83) 8 (9.6) 18(21.7) 5 (6.0) 3 (3.6) 8 (9.6) 26 (31.3) 11(13.3) 4 (4.8) 50 (60.2) 12(14.5) 11(13.3) 4(4.8) 6 (7.2) DISCUSSION Although the differences between the groups did not reach the levels of statistical significance, the higher frequency of anastomotic breakdown in group C compared with the subarachnoid and extradural groups (groups A and B), together with a higher frequency of ileus after operation, suggests that spinal nerve block may have had a beneficial effect on the anastomoses, since other factors were similar in the three groups. Among the factors thought to be associated with an increased frequency of anastomotic dehiscence are increasing age, a haematocrit before operation of less than 35%, the presence of peritonitis, blood transfusion, increasing operative duration, rectal anastomoses, low plasma protein concentrations, and resections of tumours which have metastasized or of tumours adherent to adjacent structures (Irvin and Goligher, 1973; Schrock, Deveney and Dunphy, 1973). Findings have varied as to whether elective procedures compared with emergency operations have a significantly lower breakdown rate (Irvin and Goligher, 1973). All operations in the present study were elective procedures. The ages of the patients were similar in all groups and none was anaemic before operation. The duration of operation was about 1 h in all groups, and the frequency of rectal anastomosis was highest in the subarachnoid group (group A), which had the lowest frequency of anastomotic breakdown.

5 SPINAL NERVE BLOCK AND LARGE BOWEL ANASTOMOSIS 181 TABLE IV. Additional data for patients whose anastomosis broke down compared with other patients Anastomotic fate Broke down (»i = 11) mean SEM Remained intact (»! = = 83) mean SEM Age (yr) Haemoglobin (g dl" 1 ) Duration of operation (min) Minimum mean arterial pressure during operation (mm Hg) Oral fluids started (h after operation) I.v. fluids stopped (h after operation) Hospital stay (days after operation) Early ileus Late ileus Wound infection Wound dehiscence Drain discharge Death Morphine Pethidine * No. of patients t 4* 9 2 * 0.01 >P>0.05. t-p<0.01. XData for groups A and B only («x = 5;», = 63) % group total ' * No. of patients t 3* % group total If a beneficial effect from spinal nerve block is present, it may be a result of better operating conditions, increased intestinal tone, decreased haemorrhage, an effect on blood flow at the anastomotic site, the avoidance of neostigmine, or any combination of these factors. Spinal nerve block produces sympathetic denervation of the small and large bowel. The small bowel and right hemi receive their parasympathetic innervation from the vagus nerve, which is not involved in spinal block, and the effects of the sympathetic block are an increase in the propulsive force of peristalsis and an increase in tone of the bowel wall (Greene, 1969). The left hemi and rectum receive their parasympathetic innervation from the sacral roots, and so both sympathetic and parasympathetic denervation occur with spinal nerve block. However, the net effect seems to be an increase in bowel tone. This might result in better construction of the anastomosis, or less marked changes in intraic pressure in the period immediately after anaesthesia. The increase in bowel tone probably causes the passage of flatus and faeces in the period immediately after operation, an occurrence which we have noticed in most patients receiving spinal nerve block. This may minimize gaseous distension leading to a gaseous leak at the anastomosis, which could result in anastomotic breakdown. Abdominal wall relaxation may be better under spinal nerve block as compared with myoneural block. In a series of 650 cases of anterior resection of rectum, and left hemicolectomy, Whitaker, Dixon and Greatorex (1970) found that the frequency of anastomotic dehiscence, averaging 16.1%, was proportional to the volume of blood transfused during operation. In experiments on dogs in which 10% of the blood volume was removed, they found a dramatic decrease in ic blood flow, which was not always reversed by the reinfusion of the shed blood. They concluded that the anastomotic leakage rate in their human series was probably associated with blood loss during operation rather than blood transfusion. They found also that sympathetic nerve section in the dogs resulted in restoration of normal ic blood flow. In the present study, the mean blood loss was very much less in groups A and B than in group C. The small blood loss during spinal nerve block is probably

6 182 BRITISH JOURNAL OF ANAESTHESIA a result of a combination of decreased local arterial and venous pressures as a consequence of arterial hypotension, venous dilatation and posture (Moir, 1968). The percentage reduction in mean arterial pressure values from before operation to minimum during operation was similar in group A (58.5%) and group B (59.6%). These decreases were large, partly because the patients were anaesthetized. The percentage reduction of mean arterial pressure was similar in the patients who had an anastomotic breakdown (60.8%) and the other patients (58.8%) when the patients who had received a spinal nerve block were considered. Schrock, Deveney and Dunphy (1973) found that the anastomotic breakdown rate more than doubled in patients who were hypotensive (denned by them as a systolic arterial pressure decrease of 55 mm Hg below baseline for 15 min or longer) during operation, but their patients were hypotensive almost certainly because of haemorrhage. The findings in the present study do not suggest that hypotension associated with vasodilatation has a deleterious effect on bowel anastomoses. Neostigmine has been shown to increase intraic pressure dramatically, the effect not being prevented entirely by the administration of atropine either with or before the neostigmine (Bell and Lewis, 1968; Wilkins et al., 1970), and in a series of ileo-rectal anastomoses (Bell, 1970) the incidence of anastomotic breakdown was much higher in patients receiving neostigmine (36%) than in controls (4%). The effects of morphine on the were reported by Painter (1963). He found that morphine caused contraction rings in the, and produced additional contraction of the segments formed. Thus, the contents were not free to escape and high pressures developed within the segments. He found that pethidine did not produce these effects, and suggested that morphine might tend to disrupt an anastomosis in the. The figures in the present study show a trend which supports this view although the differences between morphine and pethidine are not statistically significant. In those patients who received morphine or a drug containing morphine, the frequency of anastomotic breakdown was markedly less in the groups who had a spinal nerve block, although again the differences do not attain statistical significance. This investigation had the disadvantage of being retrospective, with the result that the conditions of the study were not controlled rigidly. In addition, the number of patients studied was small. It is difficult in any one hospital to obtain data in a reasonable space of time on large numbers of patients undergoing large bowel anastomoses and we feel that the findings from the present study suggest that wider collaborative studies, to determine separately the effects on large bowel anastomoses of spinal nerve block and narcotic analgesics, are important requirements in the effort to reduce the high incidence of, and mortality from, anastomotic breakdown. REFERENCES Bell, C. M. A. (1970). Neostigmine and anastomotic disruption. Proc. R. Soc. Med., 63, 752. Lewis, C. B. (1968). Effect of neostigmine on integrity of ileo-rectal anastomoses. Br. Med. J., 3, 587. Goligher, J. C, Morris, C, McAdam, W. A. F., DeDombal, F. T., and Johnston, D. (1970). A controlled trial of inverting versus everting intestinal suture in clinical large bowel surgery. Br. J. Surg., 57, 817. Greene, N. M. (1969). In Physiology of Spinal Anesthesia, 2nd edn, p Baltimore: Williams and Wilkins. Irvin, T. T., and Goligher, J. C. (1973). Aetiology of disruption of intestinal anastomoses. Br.J. Surg., 60,461. Lee, J. A., and Atkinson, R. S. (1973). In A Synopsis of Anaesthesia, 7th edn, p Bristol: John Wright and Sons. Moir, D. D. (1968). Blood loss during major vaginal surgery. Br. J. Anaesth., 40, 233. Painter, N. S. (1963). The effect of morphine in diverticulosis of the. Proc. R. Soc. Med., 56, 800. Schrock, T. R., Deveney, C. W., and Dunphy, J. E. (1973). Factors contributing to leakage of ic anastomoses. Ann. Surg., 177, 513. Whitaker, B. L., Dixon, R. A., and Greatorex, G. (1970). Anastomotic failure in relation to blood transfusion and blood loss. Proc. R. Soc. Med., 63, 751. Wilkins, J. L., Hardcastle, J. D., Mann, C. V., and Kaufman, L. (1970). Effects of neostigmine and atropine on motor activity of ileum, and rectum of anaesthetized subjects. Br. Med. J., 1, 793. BLOCAGE DU NERF SPINAL POUR L'ANASTOMOSE DU GROS INTESTIN Etude retrospective RESUME On a compare, au cours d'une etude retrospective, 68 anastomoses du gros intestin effectuees sur des malades soumis a un blocage sous-arachnoidien ou extradural du nerf spinal et a une anesthesie generate legere, a 26 anastomoses sur des malades n'ayant recu qu'une anesthisie generate. II s'est produit une dehiscence dans 7,4% des cas d'anastomoses effectuees sous blocage du nerf spinal, alors que dans le groupe temoin ce chiffre a et de 23,1%. Sur les malades recevant de la morphine, la dehiscence anastomosique s'est produite dans 15,2% des operations, alors que pour ceux recevant de la pethidine le pourcentage n'a ete que de 5,9 %. Ces differences n'ont pas une importance statistique tres significative, mais les resultats obtenus font ressortir la necessite de proceder a des etudes plus pouss6es.

7 SPINAL NERVE BLOCK AND LARGE BOWEL ANASTOMOSIS 183 LEITUNGSANASTHESIE IM OBEREN ROCKENMARK BEI DICKDARMANASTOMOSE Ruckblickende Studie ZUSAMMENFASSUNG Im Rahmen einer riickblickenden Studie wurden 68 Dickdarmanastomosen, die an Patienten unter subarachnoidaler oder extraduraler Ruckenmarksleitungsanasthesie zusammen mit einer leichten allgemeinen Narkose vorgenommen worden waren, mit 26 anderen Anastomosen verglichen, die an Patienten durchgefiihrt worden waren, die nur unter einer allgemeinen Narkose standen. Zu Nahtdehiszenzen kam es bei 7,4% der mit Leitungsanasthesie durchgefuhrten Anastomosen, verglichen mit 23,1% in der Kontrollgruppe. Bei morphiumbehandelten Patienten erfolgte eine Nahtdehiszenz nach der Operation bei 15,2% aller Falle, verglichen mit 5,9% bei den Patienten, die mit Pethidin behandelt worden waren. Diese Unterschiede sind von keiner statistischen Bedeutung, doch die Resultate zeigen die Notwendigkeit fiir umfassendere Studien. BLOQUEO DEL NERVIO ESPINAL SUPERIOR PARA ANASTOMOSIS DEL INTESTINO GRUESO Un estudio retrospectivo SUMARIO En un estudio retrospectivo, se compararon 68 anastomosis del intestino grueso realizados en pacientes sometidos a bloqueo del nervio espinal subaracnoides o extradural con anestesia general ligera, con 26 anastomosis en pacientes que recibieron anestesia general sola. Se produjo dehiscencia en un 7,4% de los anastomosis realizados bajo bloqueo del nervio espinal en comparacion con un 23,1% en el grupo de control. En los pacientes que recibieron morfina, se produjo dehiscencia anastomotica despues de un 15,2% de las operaciones, en comparacion con un 5,9% en el caso de los pacientes que recibieron petidina. Estas diferencias no son estadisticamente significativas. Sin embargo, los resultados indican la necesidad de llevar a cabo estudios futuros mas extensos.