Does Mpha Sympathetic Blockade Prevent Urinary Retention Following Anorectal Surgery? Peter A. Cataldo, M.D., AnthonyJ. Senagore, M.D., M.S. From the Department of Surgical Research, Ferguson Hospital, Grand Rapids, Michigan Urinary retention is the most common complication after anorectal surgery, with rates as high as 52 percent reported. With the trend toward early discharge, avoidance of this complication is particularly important. Perioperative fluid restriction and the use of short-acting anesthetics have been shown to be effective in decreasing postoperative urinary retention rates but are not applicable in all cases. Reflex sympathetic stimulation, possibly as a result of perianal pain, may lead to increased muscular tone of the internal sphincter at the bladder neck. This theory had led to the effective use of alpha-adrenergic blockade in the treatment of established cases of urinary retention after anorectal surgery, herniorrhaphy, and major pelvic surgery. However, the prophylactic role of alpha blockade after anorectal surgery has not been studied. In a double-blind, prospective, randomized study, 51 patients were treated with either prazosin and alpha-adrenergic blocker or placebo prior to and immediately after elective anorectal surgery. Urinary retention rates were similar in the two groups. At this time, prophylactic alpha-adrenergic blockade is not recommended for the prevention of urinary retention after anorectal surgery. [Key words: Postoperative urinary retention; Alpha sympathetic blockade; Anorectal surgery] Cataldo PA, Senagore AJ. Does alpha sympathetic blockade prevent urinary retention following anorectal surgery? Dis Colon Rectum 1991;34:1113-1116. rinary retention is the most frequent complication after minor anorectal procedures, with rates as high as 52 p e r c e n t reported. 1 With increasing financial constraints and the trend toward early discharge, avoidance of this perioperative complication is particularly important. Fluid restriction in the perioperative p e r i o d and the use of short-acting anesthetics have both b e e n shown to r e d u c e the incidence of postoperative urinary r e t e n t i o n ) ' 3 However, fluid restriction and short-acting anesthetics may not be applicable in all cases. Various pharmaceutical agents have b e e n u s e d in attempts to prevent or treat urinary retention. Bethanechol (UrecholineTM; Merck, Rahway, NJ), a cholinergic agent closely related to acetylcholine, has frequently b e e n criticized. T h r o u g h
U
its parasympathomimetic effects, b e t h a n e c h o l increases detrusor tone, t h e r e b y facilitating bladder emptying. Bethanechol is a useful agent for the treatment of established cases of urinary retention but has not b e e n effective prophylactically. 4 Alpha sympathetic stimulation s e c o n d a r y to postoperative pain is responsible for increasing the tone of the internal sphincter at the bladder neck, thereby contributing to postoperative urinary retention after anorectal surgery. Alpha-adrenergic blockade has d e m o n s t r a t e d effectiveness in the treatment of established cases of urinary retention. 5 Additionally, alpha blockers are k n o w n to be effective in preventing urinary retention after major rectal surgery. 6 Prazosin, an alpha-adrenergic blocker, was dev e l o p e d for the treatment of hypertension. Prazosin mediates its antihypertensive effect via postsynaptic alpha-adrenergic blockade leading to peripheral arteriolar dilatation. Peak action is at three hours after oral absorption. Metabolism occurs predominantly in the liver. Side effects attributed to prazosin include dizziness (10 p e r c e n t ) , headaches (8 p e r c e n t ) , drowsiness (8 p e r c e n t ) , weakness (7 percent), nausea (5 p e r c e n t ) , and syncope (
0.5 - - 2
hours 8 hours--12 h o u r s - HOURS POSTOPERATIVELY
Figure 1. Postoperative pain scale after anorectal surgery: 0 = no pain, 1 = mild pain, 2 = moderate pain, 3 = worst pain ever (praz = prazosin; void = successful voiding). D a t a are presented as mean ___SD.
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ALPHA BLOCKADE AFTER ANORECTAL SURGERY
total perioperative fluids. No parameter was useful as a predictor of postoperative urinary retention. Mortality for the study period was zero. However, a number of minor postoperative, medicationrelated complications occurred (Table 3). Nine patients (36 percent) in Group 1 and eight patients (33 percent) in Group 2 complained of nausea or vomiting. Dizziness occurred in four patients (16 percent) in Group 1 and two patients (8.3 percent) in Group 2. Postural hypotension occurred in two patients (8 percent) in each group. One patient (4 percent) in Group 1 had a single syncopal episode; none occurred in Group 2. The above complications were compared between groups, and again there were no significant differences.
DISCUSSION Urinary retention is the most common complication after anorectal surgery and results in hospitalization, which may not otherwise be necessary. Hemorrhoidectomy, in particular, is associated with postoperative urinary retention rates as high as 52 percent. 1 In this era of cost containment and early postoperative discharge, avoiding postoperative complications (which might delay discharge) is particularly important. Many factors have been associated with postoperative urinary retention. Bailey and Ferguson 2 linked perioperative fluid restriction to successful voiding. They reported urinary retention rates as low as 3.5 percent when perioperative fluids were restricted to a total of 250 cc until successful voiding. Petros and Bradley 3 showed that long-acting spinal anesthetics, as well as total perioperative fluid volumes greater than 1,000 cc, were associated with high risks of urinary retention. Table 2. Incidence of Urinary Retention and Successful Voiding Between the Treatment Groups Urinary Retention
Spontaneous Voiding
10 (40%) 12 (50%)
15 (60%) 12 (50%)
Prazosin (n = 25) Placebo (n = 24)
1115
Various agents have been used in attempts to decrease urinary retention. Urecholine TM, through its parasympathomimetic effects, increases bladder tone and thereby facilitates bladder emptying. Urecholine TM has been useful in the treatment of established urinary retention but has not been effective prophylactically. 4 The etiology of urinary retention after anorectal surgery remains unknown. The combination of an overdistended bladder and a closed bladder neck may be a major etiologic factor. Excessive perioperative fluid administration, leading to bladder distention, has been associated with increased rates of urinary retention. 2 It has been postulated that anal pain leads to increased sympathetic tone v i a a local reflex arc. Sympathetic, or alpha-adrenergic, stimulation is known to cause contraction of the internal sphincter at the bladder neck. Therefore, increased bladder neck pressures, possibly secondary to postoperative pain, may contribute to urinary retention after anorectal procedures. Alpha-adrenergic blockade has been shown to be effective in treating established cases of urinary retention. Goldman e t al. 5 showed phenoxybenzamine, an alpha-adrenergic blocker, to be effective in treating postherniorrhaphy urinary retention. Goldman e t al. 6 also showed that prophylactic phenoxybenzamine could prevent urinary retention and decrease genitourinary complications after major pelvic surgery. There have been no studies evaluating prophylactic alpha blockade in the prevention of urinary retention after anorectal surgery. To answer this question, we randomized 51 patients undergoing anorectal procedures to receive either prazosin, an alpha-adrenergic blocking agent, or placebo preoperatively and for three doses postoperatively. Groups were matched for age, sex, history of obstructive uropathy, perioperative fluid volumes, and procedure performed. Forty percent of patients in Group 1 (prazosin) and 50 percent of patients in Group 2 (placebo) developed urinary retention. The difference was not statistically significant. Unusually high rates of urinary retention occurred in both groups. Overzealous operative fluid
Table 3. Incidence of Postoperative Complications in the Prazosin and Placebo Groups Prazosin (n = 25) Placebo (n = 24)
Nausea/Vomiting
Dizziness
Hypotension
Syncope
9 (36) 8 (33)
4 (16) 2 (8)
2 (8) 2 (8)
1 (4) 0 (0)
1116
CATALDO AND SENAGORE
administration (mean = 850 cc), required because of hypotension induced by spinal anesthesia, may have been partially responsible. Patient and nursing staff awareness may have also played a role. All patients were informed as to the nature of the study (prevention of urinary retention) before informed consent was obtained. Nursing staff were trained concerning data collection and indications for catheterization. This combination may have created increased patient anxiety and subsequent difficulty in voiding for both study groups. The data indicate that prophylactic alpha blockade had no significant effect in preventing postoperative urinary retention. This was true regardless of age, sex, total pain score, perioperative fluid volume, or procedure performed. Perhaps other factors unknown at this time are more closely related to urinary retention after anorectal surgery. At this time, there appears to be no role for the routine use of prophylaxis for alpha-adrenergic blockade prior to anorectal surgery for the prevention of urinary retention.
CONCLUSIONS Urinary retention is com m on after anorectal surgery. Perioperative fluid administration and choice of anesthetic may influence postoperative urinary retention rates. Anorectal procedures performed
Dis Colon Rectum, December 1991
under local anesthesia with intravenous sedation combined with minimal perioperative fluid administration may result in the lowest rates of urinary retention. Prophylactic alpha blockade has no role in the prevention of urinary retention after minor anorectal surgery. Its role in the therapy of established cases of urinary retention remains undefined. REFERENCES 1. Corman ML. Colon and rectal surgery. 2nd ed. Philadelphia: JB Lippincott, 1989:84-5. 2. Bailey HR, Ferguson JA. Prevention of urinary retention by fluid restriction following anorectal operations. Dis Colon Rectum 1976;19:250-2. 3. Petros JG, Bradley TM. Factors influencing postoperative urinary retention in patients undergoing surgery for benign anorectal disease. Am J Surg 1990; 159:375-99. 4. Bowers FJ, Hartmann R, Khanduja KS, Hardy TG Jr, Aguilar PS, Stewart WR. Urecholine prophylaxis for urinary retention in anorectal surgery. Dis Colon Rectum 1987;30:41-2. 5. Goldman G, LeviavA, Mazor A, e t al. Alpha adrenergic blocker for post hernioplasty urinary retention. Arch Surg 1989;123:35-6. 6. Goldman G, Kahn PJ, Kashtan H, StadlerJ, Wiznitzert T. Prevention and treatment of urinary retention after surgical treatment of colon and rectum with alpha blockers. Surg Gynecol Obstet 1988;166:447-50.
U
its parasympathomimetic effects, b e t h a n e c h o l increases detrusor tone, t h e r e b y facilitating bladder emptying. Bethanechol is a useful agent for the treatment of established cases of urinary retention but has not b e e n effective prophylactically. 4 Alpha sympathetic stimulation s e c o n d a r y to postoperative pain is responsible for increasing the tone of the internal sphincter at the bladder neck, thereby contributing to postoperative urinary retention after anorectal surgery. Alpha-adrenergic blockade has d e m o n s t r a t e d effectiveness in the treatment of established cases of urinary retention. 5 Additionally, alpha blockers are k n o w n to be effective in preventing urinary retention after major rectal surgery. 6 Prazosin, an alpha-adrenergic blocker, was dev e l o p e d for the treatment of hypertension. Prazosin mediates its antihypertensive effect via postsynaptic alpha-adrenergic blockade leading to peripheral arteriolar dilatation. Peak action is at three hours after oral absorption. Metabolism occurs predominantly in the liver. Side effects attributed to prazosin include dizziness (10 p e r c e n t ) , headaches (8 p e r c e n t ) , drowsiness (8 p e r c e n t ) , weakness (7 percent), nausea (5 p e r c e n t ) , and syncope (
0.5 - - 2
hours 8 hours--12 h o u r s - HOURS POSTOPERATIVELY
Figure 1. Postoperative pain scale after anorectal surgery: 0 = no pain, 1 = mild pain, 2 = moderate pain, 3 = worst pain ever (praz = prazosin; void = successful voiding). D a t a are presented as mean ___SD.
Vol. 34, No. 12
ALPHA BLOCKADE AFTER ANORECTAL SURGERY
total perioperative fluids. No parameter was useful as a predictor of postoperative urinary retention. Mortality for the study period was zero. However, a number of minor postoperative, medicationrelated complications occurred (Table 3). Nine patients (36 percent) in Group 1 and eight patients (33 percent) in Group 2 complained of nausea or vomiting. Dizziness occurred in four patients (16 percent) in Group 1 and two patients (8.3 percent) in Group 2. Postural hypotension occurred in two patients (8 percent) in each group. One patient (4 percent) in Group 1 had a single syncopal episode; none occurred in Group 2. The above complications were compared between groups, and again there were no significant differences.
DISCUSSION Urinary retention is the most common complication after anorectal surgery and results in hospitalization, which may not otherwise be necessary. Hemorrhoidectomy, in particular, is associated with postoperative urinary retention rates as high as 52 percent. 1 In this era of cost containment and early postoperative discharge, avoiding postoperative complications (which might delay discharge) is particularly important. Many factors have been associated with postoperative urinary retention. Bailey and Ferguson 2 linked perioperative fluid restriction to successful voiding. They reported urinary retention rates as low as 3.5 percent when perioperative fluids were restricted to a total of 250 cc until successful voiding. Petros and Bradley 3 showed that long-acting spinal anesthetics, as well as total perioperative fluid volumes greater than 1,000 cc, were associated with high risks of urinary retention. Table 2. Incidence of Urinary Retention and Successful Voiding Between the Treatment Groups Urinary Retention
Spontaneous Voiding
10 (40%) 12 (50%)
15 (60%) 12 (50%)
Prazosin (n = 25) Placebo (n = 24)
1115
Various agents have been used in attempts to decrease urinary retention. Urecholine TM, through its parasympathomimetic effects, increases bladder tone and thereby facilitates bladder emptying. Urecholine TM has been useful in the treatment of established urinary retention but has not been effective prophylactically. 4 The etiology of urinary retention after anorectal surgery remains unknown. The combination of an overdistended bladder and a closed bladder neck may be a major etiologic factor. Excessive perioperative fluid administration, leading to bladder distention, has been associated with increased rates of urinary retention. 2 It has been postulated that anal pain leads to increased sympathetic tone v i a a local reflex arc. Sympathetic, or alpha-adrenergic, stimulation is known to cause contraction of the internal sphincter at the bladder neck. Therefore, increased bladder neck pressures, possibly secondary to postoperative pain, may contribute to urinary retention after anorectal procedures. Alpha-adrenergic blockade has been shown to be effective in treating established cases of urinary retention. Goldman e t al. 5 showed phenoxybenzamine, an alpha-adrenergic blocker, to be effective in treating postherniorrhaphy urinary retention. Goldman e t al. 6 also showed that prophylactic phenoxybenzamine could prevent urinary retention and decrease genitourinary complications after major pelvic surgery. There have been no studies evaluating prophylactic alpha blockade in the prevention of urinary retention after anorectal surgery. To answer this question, we randomized 51 patients undergoing anorectal procedures to receive either prazosin, an alpha-adrenergic blocking agent, or placebo preoperatively and for three doses postoperatively. Groups were matched for age, sex, history of obstructive uropathy, perioperative fluid volumes, and procedure performed. Forty percent of patients in Group 1 (prazosin) and 50 percent of patients in Group 2 (placebo) developed urinary retention. The difference was not statistically significant. Unusually high rates of urinary retention occurred in both groups. Overzealous operative fluid
Table 3. Incidence of Postoperative Complications in the Prazosin and Placebo Groups Prazosin (n = 25) Placebo (n = 24)
Nausea/Vomiting
Dizziness
Hypotension
Syncope
9 (36) 8 (33)
4 (16) 2 (8)
2 (8) 2 (8)
1 (4) 0 (0)
1116
CATALDO AND SENAGORE
administration (mean = 850 cc), required because of hypotension induced by spinal anesthesia, may have been partially responsible. Patient and nursing staff awareness may have also played a role. All patients were informed as to the nature of the study (prevention of urinary retention) before informed consent was obtained. Nursing staff were trained concerning data collection and indications for catheterization. This combination may have created increased patient anxiety and subsequent difficulty in voiding for both study groups. The data indicate that prophylactic alpha blockade had no significant effect in preventing postoperative urinary retention. This was true regardless of age, sex, total pain score, perioperative fluid volume, or procedure performed. Perhaps other factors unknown at this time are more closely related to urinary retention after anorectal surgery. At this time, there appears to be no role for the routine use of prophylaxis for alpha-adrenergic blockade prior to anorectal surgery for the prevention of urinary retention.
CONCLUSIONS Urinary retention is com m on after anorectal surgery. Perioperative fluid administration and choice of anesthetic may influence postoperative urinary retention rates. Anorectal procedures performed
Dis Colon Rectum, December 1991
under local anesthesia with intravenous sedation combined with minimal perioperative fluid administration may result in the lowest rates of urinary retention. Prophylactic alpha blockade has no role in the prevention of urinary retention after minor anorectal surgery. Its role in the therapy of established cases of urinary retention remains undefined. REFERENCES 1. Corman ML. Colon and rectal surgery. 2nd ed. Philadelphia: JB Lippincott, 1989:84-5. 2. Bailey HR, Ferguson JA. Prevention of urinary retention by fluid restriction following anorectal operations. Dis Colon Rectum 1976;19:250-2. 3. Petros JG, Bradley TM. Factors influencing postoperative urinary retention in patients undergoing surgery for benign anorectal disease. Am J Surg 1990; 159:375-99. 4. Bowers FJ, Hartmann R, Khanduja KS, Hardy TG Jr, Aguilar PS, Stewart WR. Urecholine prophylaxis for urinary retention in anorectal surgery. Dis Colon Rectum 1987;30:41-2. 5. Goldman G, LeviavA, Mazor A, e t al. Alpha adrenergic blocker for post hernioplasty urinary retention. Arch Surg 1989;123:35-6. 6. Goldman G, Kahn PJ, Kashtan H, StadlerJ, Wiznitzert T. Prevention and treatment of urinary retention after surgical treatment of colon and rectum with alpha blockers. Surg Gynecol Obstet 1988;166:447-50.
