Manometric Study of Anal Fissure Treated by Subcutaneous Lateral Internal Sphincterotomy
A
MATTHEW J. McNAMARA, M.B., B.S., F.R.A.C.S., JOHN P. PERCY, M.B., B.S., F.R.A.C.S., and IAN R. FIELDING, M.B., B.S., F.R.A.C.S.
A prospective, manometric trial of anal fissure treated by subcutaneous lateral internal sphincterotomy (SLIS) was designed to elucidate the pathophysiology of this condition. Anorectal manometry with a closed, precalibrated, water-filled microballoon using the station pull-through technique was performed on 13 patients with anal fissure before, and at one and 150 days after SLIS. The results were compared with 13 control subjects, matched for age and sex, who had no history of anal disease. Both resting pressure (RP) and maximum voluntary contraction pressure (MVCP) were measured at centimeter intervals of the anal canal. At all levels RP was significantly higher in the preoperative patients compared with controls (p < 0.0001). After operation RP fell significantly at all levels with the result that there was no significant difference in RP between postoperative patients and controls, except at 4 cm from the anal verge, where there remained a significant elevation in RP in the postoperative group. There was no significant difference in the two sets of postoperative manometric results. All patients underwent rapid healing and resolution of their symptoms. MVCP did not change significantly after operation, nor did it differ from the control values. This suggests that the increase in RP is due to activity of the internal anal sphincter. This over-activity is present throughout the entire length of the internal anal sphincter and sphincterotomy of its lowest portion returns RP to normal values throughout most of the anal canal.
A
NAL FISSURE IS the most common cause of acute anal pain and in the most severe cases becomes almost incapacitating. However, despite this, its etiology and pathophysiology remain obscure. Previous studies in the literature1''4 have been conflicting and this prospective, manometric study was designed, by comparing fissure patients with controls, to determine the relative activity of the internal and external sphincters and to examine the effect of subcutaneous lateral internal sphincterotomy (SLIS) on patients with anal fissure. Address reprint requests to Dr. J. Percy, Berry Road Medical Center, Berry Road, St. Leonards, New South Wales 2065, Australia. Accepted for publication: May 22, 1989.
235
From the Colon and Rectal Unit, Royal North Shore Hospital, Sydney, Australia
Materials and Methods
Thirteen patients (nine women and four men) with a mean age of 45 years (range, 25 to 75 years) with a symptomatic anal fissure confirmed on physical examination, were entered in the study. SLIS was performed under general or spinal anesthesia in the lithotomy position. The operative technique involved infiltration with 1% xylocaine in the submucosal and intersphincteric planes followed by an annular stab incision in the left lateral perianal region. Scissor dissection was then performed in the above planes to the level of the dentate line. The internal anal sphincter was then divided to this point and the length of the sphincter division was recorded in centimeters. Anorectal manometry was performed on the fissure patients before and then after operation on days 1 and 150. Thirteen control patients matched for age and sex with no history of anal disease were also studied manometrically. No anal manipulations were performed before manometry to avoid the effects of anal dilatation on sphincter pressures. Manometry was performed using a precalibrated, closed, water-filled, 2.5 mm microballoon (Fig. 1) connected via a 1.5-mm nondistensible polypethylene tube to a pressure transducer and the results were printed on a Hewlett Packard chart recorder. The patients were placed comfortably in the left lateral position. Measurement of resting position (RP) relative to atmospheric pressure was then performed using the station pullthrough technique, with recordings in centimeters of water (H20) made from rectal ampulla to anal verge, at centimeter intervals. The procedure was then repeated, this time with maximum voluntary contraction, to determine the activity of the external anal sphincter. Maximun vol-
236
MCNAMARA, PERCY, AND FIELDING
Ann.
Surg. February 1990 -
postoperative manometric sessions revealed no significant difference, so the results of day 1 were used to simplify the comparison (Fig. 3). After subcutaneous, lateral internal sphincterotomy, there was a significant fall in RP at all four levels of the anal canal compared to the preoperative values (p < 0.0001), despite the fact that the mean recorded length of the sphincterotomy was only 2 cm. As a result of this fall in RP, the values at the 1-, 2-, and 3-cm levels were statistically similar to the control
values. However at 4 cm from the anal verge, despite a
FIG. 1. Microballoon, catheter, and transducer used for anal manometry.
untary contraction pressure (MVCP) was defined as the increment of maximum pressure recorded above RP. Despite initial apprehension, none of the patients complained of discomfort with the procedure, despite close questioning. All data was assessed by calculation of normal distribution plots and found to be normally distributed. The paired Student's t test was used to compare the pre- and postoperative results. The nonpaired Student's t test was used to compare the fissure patients to the controls. All calculations were performed on a DEC PBS/I 1/23 computer using a Minitab statistical package. Results RP was found to be significantly higher in the anal fissure patients compared with the control group at the 1-, 2-, 3-, and 4-cm levels from the anal verge (p < 0.0001; Fig. 2). Examination of the results in the series of two
significant fall (p < 0.0001), the RP remained significantly higher than the control level (p < 0.0015; Fig. 2). Examination of the MVCP, which is largely a reflection of external sphincter activity, revealed no significant change after operation (Fig. 4). All patients had good to dramatic relief of their symptoms and usually had almost painless bowel motions within two days. One patient had mild impairment offlatus control for about ten days. Aside from this the only morbidity associated with SLIS was some slight bruising at the operative site. Discussion Treatment ofanal fissure by sphincterotomy is not new and was first suggested in 1818 by Boyer. The SLIS used in this series was basically a modification of Parks'"5 and Notaras'"6"17 techniques. Eisenhammer'8"9 proposed that in patients with anal fissure, spasm of the internal anal sphincter occurred, resulting in a chronic contracture and thus producing a chronic fissure. Duthie and Bennett,' using a water perfusion technique, found no difference in manometric pressures between fissure patients and controls. Keighley2 also found no manometric difference in seven patients with chronic anal fissures compared with 20 controls. However, in a later and larger study with Arabi,3 he found that there was increased RP in patients with anal fissure. lUU
-
60-
mean
resting pressure
(cm H20)
mean pressure
60
(cmH20) (meantSD)
40
1
1±
° day I Cl - day 150 -
20 1.0
2.0
3.0
4.0
distance from anal verge(cm) 11Pro-op inPost-op FIG. 2. Resting pressure.
C
Control
01.0
2.0
3.0
4.0
distance from anal verge(cm) FIG. 3. Postoperative resting pressure (day 1 versus day 150).
Vol. 211 * No.2
MANOMETRIC STUDY OF ANAL FISSURE
14011
pressure 120
}
(cm.H20) 100. (mean±SD) so
j
so 40 20 0-
pre-op
post-op
control
FIG. 4. Maximum voluntary contraction.
Using latex balloons Abcarian8 could find no statistical difference in RP in eight patients with chronic anal fissure compared to ten controls. In our study we found a statistically significant higher pressure in patients with anal fissure compared with a controlled group. This result correlates with most other published series.3A4'6'7'9" 1-14 However Arabie3 and Kuypers9 did not include postoperative results in their series. In contrast to Olsen'4 and Abcarian,8 who found no significant reduction in RP after lateral internal sphincterotomy, we found up to a 50% reduction in RP after this procedure, and this is in agreement with a number of other series.4'5'7"'1'2 In the studies by Marby5 and Boulos,'I comparative statements are difficult because no control groups were included. Nothman6 described an abnormal rectoanal inhibitory reflex that was characterized by an overshoot contraction following a normal relaxation. However, even though he found elevated RPs before operation, he did not mention postoperative values aside from describing loss of this overshoot phenomenon. Kuypers9 believed that because the internal anal sphincter reacted normally, there was no spasm of the internal anal sphincter, and was unsure whether the increase in RP was due to activity of the internal or external sphincters. Most authors, who have found increased RP in patients with anal fissure, have not been sure if the high pressure found is a cause or result of the anal fissure. Gibbons'3 believed anal hypertonia produced ischemia that prevented the fissure from healing; however his series included no operative results for comparison. Most authors have reported one value for RP in contrast to our series, which gives values at four levels of the anal canal. Cerdan7 also reported his results in this manner. We found significant reductions in RP at all levels of the anal canal, but the postoperative values at 1, 2, and 3 cm from anal verge after SLIS were still in the normal range, despite the fact that the internal anal sphincter had been divided over its lower half. If this procedure had been done on normal patients, a decrease in RP would be expected, as
237
can occur in inadvertent internal sphincter division during hemorrhoidectomy. This would appear to suggest that there is an underlying hyperactivity of the internal anal sphincter. This is also supported by the finding that at the 4-cm level from the anal verge, despite a significant postoperative reduction and resolution of the fissure, the RP was still significantly higher than controls, which suggests some persistent spasm in the internal anal sphincter (p < 0.0015). These results are similar to those found by Cerdan;7 however he did not comment on the persistence of the postoperative RP above that of the control subjects in the upper anal canal, as recorded in his paper. Nor did his study include measurement of MVCP, which needs to be recorded, to be more certain that the RP found is due mainly to activity of the internal anal sphincter. This is also the only series that reports the sphincterotomy length (2 cm), and yet the total length of the internal anal sphincter is affected by the procedure. Only two other series, by Hiltunen" and Chowcat,'2 have used controls matched for age and sex, as in this series. This is an important feature because manometric pressures have been reported to change with age.20 The MVCP did not change after operation and remained similar to the control levels. This is in agreement with other series and suggests that the higher RP found in patients with an anal fissure is due to increased activity in the internal anal sphincter. These results further suggest that there is probably an underlying abnormality of the internal anal sphincter, which may predispose these patients to anal fissure. RP is significantly elevated in patients with anal fissure and it results from overactivity of the internal anal sphincter over its entire length. SLIS of the distal half of the internal anal sphincter returns RP to normal values throughout most of the anal canal, and it would appear that there is indeed a basic abnormality in the internal anal sphincter, which consists of overactivity, and this may predispose these patients to the development of anal
fissure. References 1. Duthie HL, Bennett RC. Anal sphincter pressures in fissure in ano.
Surg Gynecol Obstet 1964; 119:19-21. 2. Keighley MRB, Arabi Y, Alexander-Williams J. Anal pressures in hemorrhoids and anal fissure. Br J Surg 1976; 63:665 (abstr). 3. Arabi Y, Alexander-Williams J, Keighley MRB. Anal pressures in hemorrhoids and anal fissure. Am J Surg 1977; 134:608-10. 4. Hancock BD. The internal sphincter and anal fissure. Br J Surg 1977; 64:92-5. 5. Marby M, Alexander-Williams J, Buchman P, et al. A randomized controlled trial to compare anal dilatation with lateral subcutaneous sphincterotomy for anal fissure. Dis Col Rectum 1979; 22: 308-11. 6. Nothmann BJ, Schuster NM. Internal anal sphincter derangement with anal fissures. Gastroenterology 1974; 67:216-20. 7. Cerdan FJ, Ruiz de Leon A, Azpiroz F, et al. Anal sphincteric pressure
238 8. 9. 10. 11.
12. 13. 14.
MCNAMARA, PERCY, AND FIELDING
in fissure-in-ano before and after lateral internal sphincterotomy. Dis Col Rectum 1982; 25:198-201. Abcarian H, Lakshmanan S, Read DR, Roccaforte P. The role of internal sphincter in chronic anal fissures. Dis Col Rectum 1982; 25:525-8. Kuypers HC. Is there really sphincter spasm in anal fissure? Dis Col Rectum 1983; 26:493-4. Boulos PB, Araujo JGC. Adequate internal sphincterotomy for chronic anal fissure: subcutaneous or open technique? Br J Surg 1984; 71:360-2. Hiltunen KM, Matikainen M. Anal manometric evaluation in anal fissure. Acta Chir Scand 1986; 152:65-8. Chowcat NL, Araugjo J, Boulos PB. Internal sphincterotomy for chronic anal fissure: long term effects on anal pressure. Br J Surg 1986; 73:915-6. Gibbons CP, Read NW. Anal hypertonia in fissures: cause or effect? Br J Surg 1986; 73:443-5. Olsen J, Mortensen PE, Krogh Petersen I, Christiansen J. Anal
15. 16. 17. 18. 19.
20.
Ann. Surg. February 1990
sphincter function after treatment of fissure-in-ano by lateral subcutaneous sphincterotomy versus anal dilatation. A randomized study. Int J Colorectal Dis 1987; 2:155-7. Parks A.G. The management offissure-in-ano. Hosp Med 1976; 17: 737-8. Notaras MJ. Laterl subcutaneous sphincterotomy for anal fissureA new technique. Proc of R Soc Med 1969; 62:713. Notaras M.J. The treatment of anal fissure by lateral subcutaneous internal sphincterotomy-a technique and results. BrJ Surg 1971; 58:96-100. Eisenhammer S. The surgical correction of chronic internal anal (sphincteric) contracture. South Afr M J 1951; 25:486-9. Eisenhammer S. The evaluation of the internal anal sphincterotomy operation with special reference to anal fissure. Surg Gynecol Obstet 1959; 109:583-90. Read NW, Harford WV, Schulen AG, et al. A clinical study of patients with fecal incontinence and diarrhea. Gastroenterology 1979: 76:747.
A
MATTHEW J. McNAMARA, M.B., B.S., F.R.A.C.S., JOHN P. PERCY, M.B., B.S., F.R.A.C.S., and IAN R. FIELDING, M.B., B.S., F.R.A.C.S.
A prospective, manometric trial of anal fissure treated by subcutaneous lateral internal sphincterotomy (SLIS) was designed to elucidate the pathophysiology of this condition. Anorectal manometry with a closed, precalibrated, water-filled microballoon using the station pull-through technique was performed on 13 patients with anal fissure before, and at one and 150 days after SLIS. The results were compared with 13 control subjects, matched for age and sex, who had no history of anal disease. Both resting pressure (RP) and maximum voluntary contraction pressure (MVCP) were measured at centimeter intervals of the anal canal. At all levels RP was significantly higher in the preoperative patients compared with controls (p < 0.0001). After operation RP fell significantly at all levels with the result that there was no significant difference in RP between postoperative patients and controls, except at 4 cm from the anal verge, where there remained a significant elevation in RP in the postoperative group. There was no significant difference in the two sets of postoperative manometric results. All patients underwent rapid healing and resolution of their symptoms. MVCP did not change significantly after operation, nor did it differ from the control values. This suggests that the increase in RP is due to activity of the internal anal sphincter. This over-activity is present throughout the entire length of the internal anal sphincter and sphincterotomy of its lowest portion returns RP to normal values throughout most of the anal canal.
A
NAL FISSURE IS the most common cause of acute anal pain and in the most severe cases becomes almost incapacitating. However, despite this, its etiology and pathophysiology remain obscure. Previous studies in the literature1''4 have been conflicting and this prospective, manometric study was designed, by comparing fissure patients with controls, to determine the relative activity of the internal and external sphincters and to examine the effect of subcutaneous lateral internal sphincterotomy (SLIS) on patients with anal fissure. Address reprint requests to Dr. J. Percy, Berry Road Medical Center, Berry Road, St. Leonards, New South Wales 2065, Australia. Accepted for publication: May 22, 1989.
235
From the Colon and Rectal Unit, Royal North Shore Hospital, Sydney, Australia
Materials and Methods
Thirteen patients (nine women and four men) with a mean age of 45 years (range, 25 to 75 years) with a symptomatic anal fissure confirmed on physical examination, were entered in the study. SLIS was performed under general or spinal anesthesia in the lithotomy position. The operative technique involved infiltration with 1% xylocaine in the submucosal and intersphincteric planes followed by an annular stab incision in the left lateral perianal region. Scissor dissection was then performed in the above planes to the level of the dentate line. The internal anal sphincter was then divided to this point and the length of the sphincter division was recorded in centimeters. Anorectal manometry was performed on the fissure patients before and then after operation on days 1 and 150. Thirteen control patients matched for age and sex with no history of anal disease were also studied manometrically. No anal manipulations were performed before manometry to avoid the effects of anal dilatation on sphincter pressures. Manometry was performed using a precalibrated, closed, water-filled, 2.5 mm microballoon (Fig. 1) connected via a 1.5-mm nondistensible polypethylene tube to a pressure transducer and the results were printed on a Hewlett Packard chart recorder. The patients were placed comfortably in the left lateral position. Measurement of resting position (RP) relative to atmospheric pressure was then performed using the station pullthrough technique, with recordings in centimeters of water (H20) made from rectal ampulla to anal verge, at centimeter intervals. The procedure was then repeated, this time with maximum voluntary contraction, to determine the activity of the external anal sphincter. Maximun vol-
236
MCNAMARA, PERCY, AND FIELDING
Ann.
Surg. February 1990 -
postoperative manometric sessions revealed no significant difference, so the results of day 1 were used to simplify the comparison (Fig. 3). After subcutaneous, lateral internal sphincterotomy, there was a significant fall in RP at all four levels of the anal canal compared to the preoperative values (p < 0.0001), despite the fact that the mean recorded length of the sphincterotomy was only 2 cm. As a result of this fall in RP, the values at the 1-, 2-, and 3-cm levels were statistically similar to the control
values. However at 4 cm from the anal verge, despite a
FIG. 1. Microballoon, catheter, and transducer used for anal manometry.
untary contraction pressure (MVCP) was defined as the increment of maximum pressure recorded above RP. Despite initial apprehension, none of the patients complained of discomfort with the procedure, despite close questioning. All data was assessed by calculation of normal distribution plots and found to be normally distributed. The paired Student's t test was used to compare the pre- and postoperative results. The nonpaired Student's t test was used to compare the fissure patients to the controls. All calculations were performed on a DEC PBS/I 1/23 computer using a Minitab statistical package. Results RP was found to be significantly higher in the anal fissure patients compared with the control group at the 1-, 2-, 3-, and 4-cm levels from the anal verge (p < 0.0001; Fig. 2). Examination of the results in the series of two
significant fall (p < 0.0001), the RP remained significantly higher than the control level (p < 0.0015; Fig. 2). Examination of the MVCP, which is largely a reflection of external sphincter activity, revealed no significant change after operation (Fig. 4). All patients had good to dramatic relief of their symptoms and usually had almost painless bowel motions within two days. One patient had mild impairment offlatus control for about ten days. Aside from this the only morbidity associated with SLIS was some slight bruising at the operative site. Discussion Treatment ofanal fissure by sphincterotomy is not new and was first suggested in 1818 by Boyer. The SLIS used in this series was basically a modification of Parks'"5 and Notaras'"6"17 techniques. Eisenhammer'8"9 proposed that in patients with anal fissure, spasm of the internal anal sphincter occurred, resulting in a chronic contracture and thus producing a chronic fissure. Duthie and Bennett,' using a water perfusion technique, found no difference in manometric pressures between fissure patients and controls. Keighley2 also found no manometric difference in seven patients with chronic anal fissures compared with 20 controls. However, in a later and larger study with Arabi,3 he found that there was increased RP in patients with anal fissure. lUU
-
60-
mean
resting pressure
(cm H20)
mean pressure
60
(cmH20) (meantSD)
40
1
1±
° day I Cl - day 150 -
20 1.0
2.0
3.0
4.0
distance from anal verge(cm) 11Pro-op inPost-op FIG. 2. Resting pressure.
C
Control
01.0
2.0
3.0
4.0
distance from anal verge(cm) FIG. 3. Postoperative resting pressure (day 1 versus day 150).
Vol. 211 * No.2
MANOMETRIC STUDY OF ANAL FISSURE
14011
pressure 120
}
(cm.H20) 100. (mean±SD) so
j
so 40 20 0-
pre-op
post-op
control
FIG. 4. Maximum voluntary contraction.
Using latex balloons Abcarian8 could find no statistical difference in RP in eight patients with chronic anal fissure compared to ten controls. In our study we found a statistically significant higher pressure in patients with anal fissure compared with a controlled group. This result correlates with most other published series.3A4'6'7'9" 1-14 However Arabie3 and Kuypers9 did not include postoperative results in their series. In contrast to Olsen'4 and Abcarian,8 who found no significant reduction in RP after lateral internal sphincterotomy, we found up to a 50% reduction in RP after this procedure, and this is in agreement with a number of other series.4'5'7"'1'2 In the studies by Marby5 and Boulos,'I comparative statements are difficult because no control groups were included. Nothman6 described an abnormal rectoanal inhibitory reflex that was characterized by an overshoot contraction following a normal relaxation. However, even though he found elevated RPs before operation, he did not mention postoperative values aside from describing loss of this overshoot phenomenon. Kuypers9 believed that because the internal anal sphincter reacted normally, there was no spasm of the internal anal sphincter, and was unsure whether the increase in RP was due to activity of the internal or external sphincters. Most authors, who have found increased RP in patients with anal fissure, have not been sure if the high pressure found is a cause or result of the anal fissure. Gibbons'3 believed anal hypertonia produced ischemia that prevented the fissure from healing; however his series included no operative results for comparison. Most authors have reported one value for RP in contrast to our series, which gives values at four levels of the anal canal. Cerdan7 also reported his results in this manner. We found significant reductions in RP at all levels of the anal canal, but the postoperative values at 1, 2, and 3 cm from anal verge after SLIS were still in the normal range, despite the fact that the internal anal sphincter had been divided over its lower half. If this procedure had been done on normal patients, a decrease in RP would be expected, as
237
can occur in inadvertent internal sphincter division during hemorrhoidectomy. This would appear to suggest that there is an underlying hyperactivity of the internal anal sphincter. This is also supported by the finding that at the 4-cm level from the anal verge, despite a significant postoperative reduction and resolution of the fissure, the RP was still significantly higher than controls, which suggests some persistent spasm in the internal anal sphincter (p < 0.0015). These results are similar to those found by Cerdan;7 however he did not comment on the persistence of the postoperative RP above that of the control subjects in the upper anal canal, as recorded in his paper. Nor did his study include measurement of MVCP, which needs to be recorded, to be more certain that the RP found is due mainly to activity of the internal anal sphincter. This is also the only series that reports the sphincterotomy length (2 cm), and yet the total length of the internal anal sphincter is affected by the procedure. Only two other series, by Hiltunen" and Chowcat,'2 have used controls matched for age and sex, as in this series. This is an important feature because manometric pressures have been reported to change with age.20 The MVCP did not change after operation and remained similar to the control levels. This is in agreement with other series and suggests that the higher RP found in patients with an anal fissure is due to increased activity in the internal anal sphincter. These results further suggest that there is probably an underlying abnormality of the internal anal sphincter, which may predispose these patients to anal fissure. RP is significantly elevated in patients with anal fissure and it results from overactivity of the internal anal sphincter over its entire length. SLIS of the distal half of the internal anal sphincter returns RP to normal values throughout most of the anal canal, and it would appear that there is indeed a basic abnormality in the internal anal sphincter, which consists of overactivity, and this may predispose these patients to the development of anal
fissure. References 1. Duthie HL, Bennett RC. Anal sphincter pressures in fissure in ano.
Surg Gynecol Obstet 1964; 119:19-21. 2. Keighley MRB, Arabi Y, Alexander-Williams J. Anal pressures in hemorrhoids and anal fissure. Br J Surg 1976; 63:665 (abstr). 3. Arabi Y, Alexander-Williams J, Keighley MRB. Anal pressures in hemorrhoids and anal fissure. Am J Surg 1977; 134:608-10. 4. Hancock BD. The internal sphincter and anal fissure. Br J Surg 1977; 64:92-5. 5. Marby M, Alexander-Williams J, Buchman P, et al. A randomized controlled trial to compare anal dilatation with lateral subcutaneous sphincterotomy for anal fissure. Dis Col Rectum 1979; 22: 308-11. 6. Nothmann BJ, Schuster NM. Internal anal sphincter derangement with anal fissures. Gastroenterology 1974; 67:216-20. 7. Cerdan FJ, Ruiz de Leon A, Azpiroz F, et al. Anal sphincteric pressure
238 8. 9. 10. 11.
12. 13. 14.
MCNAMARA, PERCY, AND FIELDING
in fissure-in-ano before and after lateral internal sphincterotomy. Dis Col Rectum 1982; 25:198-201. Abcarian H, Lakshmanan S, Read DR, Roccaforte P. The role of internal sphincter in chronic anal fissures. Dis Col Rectum 1982; 25:525-8. Kuypers HC. Is there really sphincter spasm in anal fissure? Dis Col Rectum 1983; 26:493-4. Boulos PB, Araujo JGC. Adequate internal sphincterotomy for chronic anal fissure: subcutaneous or open technique? Br J Surg 1984; 71:360-2. Hiltunen KM, Matikainen M. Anal manometric evaluation in anal fissure. Acta Chir Scand 1986; 152:65-8. Chowcat NL, Araugjo J, Boulos PB. Internal sphincterotomy for chronic anal fissure: long term effects on anal pressure. Br J Surg 1986; 73:915-6. Gibbons CP, Read NW. Anal hypertonia in fissures: cause or effect? Br J Surg 1986; 73:443-5. Olsen J, Mortensen PE, Krogh Petersen I, Christiansen J. Anal
15. 16. 17. 18. 19.
20.
Ann. Surg. February 1990
sphincter function after treatment of fissure-in-ano by lateral subcutaneous sphincterotomy versus anal dilatation. A randomized study. Int J Colorectal Dis 1987; 2:155-7. Parks A.G. The management offissure-in-ano. Hosp Med 1976; 17: 737-8. Notaras MJ. Laterl subcutaneous sphincterotomy for anal fissureA new technique. Proc of R Soc Med 1969; 62:713. Notaras M.J. The treatment of anal fissure by lateral subcutaneous internal sphincterotomy-a technique and results. BrJ Surg 1971; 58:96-100. Eisenhammer S. The surgical correction of chronic internal anal (sphincteric) contracture. South Afr M J 1951; 25:486-9. Eisenhammer S. The evaluation of the internal anal sphincterotomy operation with special reference to anal fissure. Surg Gynecol Obstet 1959; 109:583-90. Read NW, Harford WV, Schulen AG, et al. A clinical study of patients with fecal incontinence and diarrhea. Gastroenterology 1979: 76:747.
