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Pain after primary inguinal herniorrhaphy: influence of surgical technique1
Pain after Primary Inguinal Herniorrhaphy: Influence of Surgical Technique Torben Callesen, MD, Karsten Bech, MD, PhD, Jens Andersen, MD, Rolf Nielsen, MD, Ole Roikjaer, MD, and Henrik Kehlet, MD, PhD
Several methods have been used for open correction of an inguinal hernia, but very few randomized comparisons of postoperative pain have been made.1 Because postoperative pain is an important problem and an important cause of impairment in activities of daily living,1 we compared three standardized surgical techniques for repair of primary indirect inguinal hernia in two randomized, prospective studies of postoperative pain.
Background: Pain is an important problem after ambulatory hernia repair. To assess the influence of the surgical technique on postoperative pain, two separate randomized, patient-blinded, controlled trials were performed in men with an indirect inguinal hernia. Study Design: In study A, 48 patients with an internal inguinal ring smaller than 1.5 cm were randomly allocated to either simple extirpation of the hernial sac or extirpation plus annulorrhaphy. In study B, 84 patients with an internal inguinal ring wider than 1.5 cm were randomly allocated to extirpation plus annulorrhaphy or extirpation plus Lichtenstein mesh repair (modified). All operations were performed under unmonitored local anesthesia with standardized perioperative analgesia using methadone and tenoxicam. Pain was scored daily for the first postoperative week and after 4 weeks on a fourpoint verbal-rank scale (no, light, moderate, or severe pain) during rest, while coughing, and during mobilization (rising to the sitting position). Use of supplementary analgesics (paracetamol) was recorded. Cumulative daily pain scores for the first postoperative week and the number of patients who used supplementary analgesics were the main outcome measures.
METHODS Patients Day-case operation under unmonitored local anesthesia is our standard procedure for elective hernia repair.2 All patients referred for elective repair of a reducible inguinal hernia aged 18 to 75 years were asked to participate in the study. The study was approved by the local ethics committee and the Danish Data Protection Agency. Before the operation, all patients gave written informed consent for participation. After intraoperative verification of a lateral (indirect) inguinal hernia, the patients were stratified according to the size of the internal inguinal ring. Study A. Patients with an internal inguinal ring smaller than 1.5 cm were randomly allocated to extirpation of the hernial sac or extirpation of the hernial sac followed by annulorrhaphy. Study B. Patients with an internal inguinal ring wider than 1.5 cm were randomly allocated to extirpation of the hernial sac followed by annulorrhaphy or extirpation of the hernial sac followed by a modified version of Lichtenstein’s tension-free mesh repair.
Results: There were no significant differences in cumulative pain scores or use of supplementary analgesics between the treatment groups in either study. Cumulative pain scores were significantly higher during coughing and mobilization than during rest in both studies. Conclusions: Choice of surgical technique for open repair of a primary indirect inguinal hernia has no influence on postoperative pain. (J Am Coll Surg 1999;188: 355–359. © 1999 by the American College of Surgeons) No competing interests declared.
Surgical technique Extirpation of the hernial sac. The aponeurosis of the external oblique muscle was incised. The hernial sac was dissected anteromedially from the spermatic
Received August 25, 1998; Accepted November 9, 1998. From the Department of Surgical Gastroenterology, Copenhagen University Hospital, H:S Hvidovre Hospital, Hvidovre, Denmark. Correspondence address: Torben Callesen, MD, H:S Rigshospitalet, HovedOrto-Centret, Anaestesi-og Operationsklinikken, DK 2100 Copenhagen Ø, Denmark. © 1999 by the American College of Surgeons Published by Elsevier Science Inc.
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cord through a slit in the cremasteric muscle and was then ligated and extirpated. Annulorrhaphy. After extirpation of the hernial sac, annulorrhaphy was achieved by tightening of the deep inguinal ring with one or two Prolene 2-0 sutures (Ethicon, Somerville, NJ) between the transverse aponeurotic arch and the iliopubic tract. Modification of Lichtenstein tension-free mesh repair. After extirpation of the hernial sac, a prolene mesh (Ethicon) was fixed by four Prolene 2-0 sutures to the pubic tubercle, to the inguinal ligament, and to the internal oblique aponeurosis; the two “legs” of the mesh were sutured together laterally to the shelving edge of the inguinal ligament. Local anesthesia and analgesia All operations were performed under unmonitored local anesthesia.3 Anesthesia consisted of an inguinal field block and incisional infiltration with bupivacaine 2.5 mg/mL combined with light sedation with midazolam. Perioperative analgesia consisted of oral tenoxicam, 40 mg in the evening and 2 hours before the operation, and 10 mg oral methadone (5 mg in patients older than 60 years) immediately before the operation. The patients received 5 mg methadone orally 8 hours postoperatively and 20 mg/day tenoxicam for 4 days. Paracetamol was recommended at up to 4 g/day for supplementary analgesia. Data sources Data were gathered by a detailed chart review that provided information about physical status and medication obtained during the visit in the outpatient clinic before operation. A detailed, standardized description of the hernia pathology and operation performed was recorded. In addition, a questionnaire was given to the patients after operation to determine pain and wound problems, supplementary use of analgesics, and additional visits to physicians during the first postoperative week. The average pain was scored once a day from the day of operation to the sixth postoperative day on a four-point verbal-rank scale (no, light, moderate, or severe pain). Separate pain scores were obtained during rest, cough, and mobilization (rising to the sitting position). The questionnaire was to be returned in a prestamped return envelope. A second questionnaire with a prestamped return envelope was mailed to the patients 4 weeks after the operation and requested information about pain and satisfaction with local anesthesia and the ambulatory setup. Pain at the end of the fourth postoperative week was scored as described above.
J Am Coll Surg
Data analysis Descriptive statistics were used for demographics characteristics. From each separate set of pain scores (rest, cough, and mobilization), we calculated cumulative pain scores (CPS) over the first week for each patient by adding the following numbers from the daily scores: 0 5 no pain; 1 5 light pain; 2 5 moderate pain; and 3 5 severe pain. All 7 days were weighted equally, so the CPS for a 7-day period ranged from 0 to 21. Cumulative scores were used to avoid repeated comparisons at different time points. The effect parameters were CPS (at rest, cough, and mobilization), 4-week pain scores, and supplementary use of analgesics. Friedman two-way analysis by ranks was used to test for intragroup differences between CPS at rest, coughing, and mobilization. Mann-Whitney U test for unpaired observations for intergroup differences for each scoring condition was used with Bonferroni correction for mass significance; 5% was chosen as the level of significance. Randomization. After intraoperative verification of an indirect hernia, the patients were assigned consecutively to study A (internal ring less than 1.5 cm) or study B (internal ring wider than 1.5 cm). By use of precoded random sequence lists, we allocated the patients in each study to one of the two relevant surgical techniques. Study assignment and random allocation were made by the surgeon. The patients were kept unaware of the surgical technique used until all pain data were recorded. Number of patients. To estimate the necessary number of patients, we assumed a normal distribution of CPS, a two-sided 5% level of significance, a power of 80%, and SD of 4 CPS units. The latter corresponds roughly to an SD of 20 mm in a 100-mm visual analogue scale as found in other studies on postherniorrhaphy pain.1 To detect a difference of 4 CPS units, 16 patients in each group were required.4 Taking into account the possibility of mass significance, the Bonferroni correction was applied, and 2 3 22 patients were calculated as necessary. Because dropouts could not be excluded, 2 3 24 patients were accepted as the necessary number in each study. The frequency of a wide internal inguinal ring was greater than that of a narrow internal ring, and for practical reasons, both studies were continued until 2 3 24 patients were included in study A (narrow); this accounted for the larger groups in study B (wide).
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Table 1. Demographic and Operative Data Study A Characteristic ASA class I II III Age (y) Bupivacaine 0.25% (mL) Midazolam (mg) Operative time (min) Time until discharge (min)
Study B
E (n 5 24)
AE (n 5 24)
AE (n 5 43)
L (n 5 41)
20 4 0 34 (28–44) 50 (44–60) 2.5 (2–3.3) 40 (30–48) 83 (70–109)
17 6 1 32 (26–46) 48 (40–51) 2 (2–3) 35 (30–36) 87 (71–115)
32 9 2 49 (38–60) 48 (41–55) 3 (2–3) 35 (35–50) 100 (70–135)
29 9 3 51 (37–68) 50 (45–56) 2.5 (2–3) 40 (35–50) 85 (70–135)
American Society of Anesthesiologists (ASA) classification is expressed as number of patients. Age, perioperative use of bupivacaine and midazolam, operative time, and time in the ward are expressed as median (interquartile range). AE, sac extirpation plus annulorrhaphy; E, sac extirpation; L, sac extirpation plus modified Lichtenstein’s tension-free mesh repair.
RESULTS Study A Table 1 presents the demographic data, including the American Society of Anesthesiologists classification and operative time. No significant differences were seen between the groups. Forty-five of the 48 patients completed the 1-week questionnaire. One patient had a transient cerebral ischemic attack 3 hours postoperatively and was hospitalized for 1 week with full recovery, and 2 patients never returned the questionnaire despite repeated reminders. Forty-three of 48 patients completed the 4-week questionnaire; 5 patients never returned it despite repeated reminders. There were no significant differences in the median CPS (Fig. 1). The CPS were significantly higher during coughing or mobilization than during rest (p , 0.01) in both groups. Pain scores were highest on day 1 and lowest on day 6 (Fig. 2), with no sig-
nificant difference between groups. Six patients having extirpation of the sac alone and 4 patients having extirpation and annulorrhaphy experienced some pain related to the hernia operation 4 weeks postoperatively. One patient with annulorrhaphy had severe pain during rest but not while coughing or rising, and 1 patient having extirpation alone experienced moderate pain while coughing. Otherwise, all pain was light. No significant differences were seen between the groups (Fig. 2). Nine of 23 patients having annulorrhaphy versus 13 of 22 having extirpation alone used some supplementary analgesics in the first postoperative week (NS). Study B Table 1 shows the demographic data and operative time. No significant differences were seen between the groups. One patient in each group did not return the
Figure 1. Cumulative pain scores (CPS) for the first postoperative week, expressed as median and interquartile range (bars). Study A: extirpation of hernial sac plus annulorrhaphy (AE) versus simple extirpation (E). Study B: extirpation of hernial sac plus annulorrhaphy (AE) versus extirpation plus modified Lichtenstein’s mesh repair (L).
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Figure 2. Study A: extirpation of hernial sac plus annulorrhaphy versus simple extirpation. Pain scores are shown at rest, coughing, and mobilization on day 1, day 6, and at 4 weeks. No significant differences were found between treatment groups at any time point.
questionnaires despite repeated reminders. All other patients returned both questionnaires. There were no significant differences in the median CPS (Fig. 1). The CPS were significantly higher during coughing and mobilization than during rest (p , 0.01) in both groups. Pain scores were highest on day 1 and lowest on day 6 (Fig. 3), with no significant differences between the groups. Eleven of 42 patients having extirpation and annulorrhaphy and 16 of 40 patients having extirpation and Lichtenstein mesh repair experienced some light pain related to the hernia operation 4 weeks postoperatively, and only 1 patient in each group had moderate pain. No patients had severe pain related to the hernia. No significant differences were seen between the groups (Fig. 3). Seventeen of 42 patients having annulorrhaphy versus 18 of 40 having Lichtenstein’s mesh repair used some supplementary analgesics in the first postoperative week (NS). Table 2 shows a post hoc calculation of the risk of overlooking a difference of 4 CPS units in both studies.
DISCUSSION Very little information is available from randomized studies on postoperative pain with different methods of open hernia repair.1,5-7 In contrast, several randomized comparisons have been made between open and laparoscopic repair. The majority showed lower pain scores after laparoscopic repair,1,8-17 and in some of these studies, less pain led to shortened convalescence.1,8,13,15 Open hernia operations are still by far the most common, however, so evaluation of postoperative pain after different open techniques is needed. The main finding in the present study was no difference in pain scorings or use of analgesics between different surgical techniques performed under standardized conditions of anesthesia and analgesia in patients undergoing open repair of a primary indirect inguinal hernia. The theoretical background for study A, comparing simple extirpation of the sac with extirpation plus annulorrhaphy, was that minimized surgical intervention might reduce pain. This concept is supported in part by Smedberg and associates,6 who found less pain after 2 and 6 weeks in patients in
Figure 3. Study B: extirpation of hernial sac plus annulorrhaphy versus extirpation plus modified Lichtenstein’s mesh repair. Pain scores are shown at rest, coughing, and mobilization on day 1, day 6, and at 4 weeks. No significant differences were found between treatment groups at any time point.
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Table 2. Post Hoc Calculations of the Risk of Overlooking a Difference of 4 Cumulative Pain Score Units Without and with the Bonferroni Correction Pain score category Rest Coughing Mobilization
Study A
Study B
3% (7%) 18% (31%) 8% (17%)
1% (2%) 7% (16%) 3% (8%)
Percentages in parentheses indicate calculations with the Bonferroni correction. Study A, extirpation versus extirpation plus annulorrhaphy; study B, extirpation plus annulorrhaphy versus extirpation plus modified Lichtenstein’s mesh repair.
whom ligation of the hernial sac was omitted compared with those who had ligation of the hernial sac. The present study, however, did not support the concept that less surgical trauma (ie, omission of annulorrhaphy) would result in less pain. The theoretical background for part B of the present study was that reduced tissue tension by implantation of a mesh instead of annulorrhaphy might reduce pain. Use of a tension-free mesh implantation has been advocated because of a favorable pain profile,18 but without sufficient documentation in controlled studies. Only two randomized studies compared Lichtenstein’s mesh repair with Shouldice hernioplasty.5,7 In one well-performed, large-scale study,7 no difference was found between groups in postoperative pain, narcotic use, or time to resume normal activities. The other study5 found less use of analgesics in the group that had Lichtenstein’s mesh repair but 88% of the patients in this group had operations performed under local anesthesia, compared with only 35% that had Shouldice hernioplasty. The local anesthetic provides pain relief for the first postoperative hours, so a marginal difference in the use of analgesics could be explained by the anesthetic rather than by the surgical technique. The present study did not support the hypothesis that a tension-free mesh repair reduces pain after repair of a primary indirect inguinal hernia. Sac extirpation, which was used in all three regimens in the present studies, is generally accepted as an integral part of the surgical treatment of an indirect inguinal hernia, although some surgeons invert the sac into the abdomen without ligation.18 The role of sac extirpation, with or without ligation, with respect to the intensity and duration of postoperative pain is unknown, except for the study by Smedberg and associates,6 who demonstrated less pain without ligation. We conclude that for comparable indirect her-
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nias, the described open surgical techniques have no important differential effects on postoperative pain, and the choice of open surgical technique should not be based on pain considerations. Acknowledgment: This study was supported by a research grant from ASTRA Pain Control, So¨derta¨lje, Sweden, and by quality assurance funds from the Copenhagen Hospital Corporation (H:S). References 1. Callesen T, Kehlet H. Postherniorrhaphy pain. Anesthesiology 1997;87:1219–1230. 2. Callesen T, Bech K, Kehlet H. The feasibility, safety and cost of infiltration anaesthesia for hernia repair. Anaesthesia 1998; 53:31–35. 3. Amid PK, Shulman AG, Lichtenstein IL. Local anesthesia for inguinal hernia repair step-by-step procedure. Ann Surg 1994; 220:735–737. 4. Young MJ, Bresnitz EA, Strom BL. Sample size nomograms for interpreting negative clinical trials. Ann Intern Med 1983; 99:248–251. 5. Kux M, Fuchsja¨ger N, Feichter A. Lichtenstein-Patch versus Shouldice-Technik bei prima¨ren Leistenhernien mit hoher Rezidivgefa¨hrdung. Chirurg 1994;65:59–62. 6. Smedberg SGG, Broome´ AEA, Gullmo A. Ligation of the hernial sac? Surg Clin North Am 1984;64:299–306. 7. Barth RJ, Burchard KW, Tosteson A, et al. Short-term outcome after mesh or Shouldice herniorrhaphy: a randomized prospective study. Surgery 1998;123:121–126. 8. Lawrence K, McWhinnie D, Goodwin A, et al. Randomised controlled trial of laparoscopic versus open repair of inguinal hernia: early results. BMJ 1995;311:981–985. 9. Stoker DL, Spiegelhalter DJ, Singh R, Wellwood JM. Laparoscopic versus open inguinal hernia repair: randomised prospective trial. Lancet 1994;343:1243–1245. 10. Maddern GJ, Rudkin G, Bessell JR, et al. A comparison of laparoscopic and open hernia repair as a day surgical procedure. Surg Endosc 1994;8:1404–1408. 11. Barkun JS, Wexler MJ, Hinchey EJ, et al. Laparoscopic versus open inguinal herniorrhaphy: preliminary results of a randomized controlled trial. Surgery 1995;118:703–710. 12. Rudkin GE, Maddern GJ. Peri-operative outcome for day-case laparoscopic and open inguinal hernia repair. Anaesthesia 1995; 50:586–589. 13. Payne JH, Grininger LM, Izawa MT, et al. Laparoscopic or open inguinal herniorrhaphy? Arch Surg 1994;129:973–981. 14. Tschudi J, Wagner M, Klaiber C, et al. Controlled multicenter trial of laparoscopic transabdominal preperitoneal hernioplasty vs Shouldice herniorrhaphy. Surg Endosc 1996;10:845–847. 15. Leibl B, Da¨ubler P, Schwarz J, et al. Standardisierte laparoskopische Hernioplastik vs. Shouldice-Reparation. Ergebnisse einer randomisierten Vergleichsstudie. Chirurg 1995;66:895–898. 16. Filipi CJ, Gaston-Johansson F, McBride PJ, et al. An assessment of pain and return to normal activity: laparoscopic herniorrhaphy vs open tension-free Lichtenstein repair. Surg Endosc 1996; 10:983–986. 17. Schrenk P, Woisetschla¨ger R, Rieger R, Wayand W. Prospective randomized trial comparing postoperative pain and return to physical activity after transabdominal preperitoneal, total preperitoneal or Shouldice technique for inguinal hernia repair. Br J Surg 1996;83:1563–1566. 18. Amid PK, Shulman AG, Lichtenstein IL. Open “tension-free” repair of inguinal hernias: the Lichtenstein technique. Eur J Surg 1996;162:447–453.
Several methods have been used for open correction of an inguinal hernia, but very few randomized comparisons of postoperative pain have been made.1 Because postoperative pain is an important problem and an important cause of impairment in activities of daily living,1 we compared three standardized surgical techniques for repair of primary indirect inguinal hernia in two randomized, prospective studies of postoperative pain.
Background: Pain is an important problem after ambulatory hernia repair. To assess the influence of the surgical technique on postoperative pain, two separate randomized, patient-blinded, controlled trials were performed in men with an indirect inguinal hernia. Study Design: In study A, 48 patients with an internal inguinal ring smaller than 1.5 cm were randomly allocated to either simple extirpation of the hernial sac or extirpation plus annulorrhaphy. In study B, 84 patients with an internal inguinal ring wider than 1.5 cm were randomly allocated to extirpation plus annulorrhaphy or extirpation plus Lichtenstein mesh repair (modified). All operations were performed under unmonitored local anesthesia with standardized perioperative analgesia using methadone and tenoxicam. Pain was scored daily for the first postoperative week and after 4 weeks on a fourpoint verbal-rank scale (no, light, moderate, or severe pain) during rest, while coughing, and during mobilization (rising to the sitting position). Use of supplementary analgesics (paracetamol) was recorded. Cumulative daily pain scores for the first postoperative week and the number of patients who used supplementary analgesics were the main outcome measures.
METHODS Patients Day-case operation under unmonitored local anesthesia is our standard procedure for elective hernia repair.2 All patients referred for elective repair of a reducible inguinal hernia aged 18 to 75 years were asked to participate in the study. The study was approved by the local ethics committee and the Danish Data Protection Agency. Before the operation, all patients gave written informed consent for participation. After intraoperative verification of a lateral (indirect) inguinal hernia, the patients were stratified according to the size of the internal inguinal ring. Study A. Patients with an internal inguinal ring smaller than 1.5 cm were randomly allocated to extirpation of the hernial sac or extirpation of the hernial sac followed by annulorrhaphy. Study B. Patients with an internal inguinal ring wider than 1.5 cm were randomly allocated to extirpation of the hernial sac followed by annulorrhaphy or extirpation of the hernial sac followed by a modified version of Lichtenstein’s tension-free mesh repair.
Results: There were no significant differences in cumulative pain scores or use of supplementary analgesics between the treatment groups in either study. Cumulative pain scores were significantly higher during coughing and mobilization than during rest in both studies. Conclusions: Choice of surgical technique for open repair of a primary indirect inguinal hernia has no influence on postoperative pain. (J Am Coll Surg 1999;188: 355–359. © 1999 by the American College of Surgeons) No competing interests declared.
Surgical technique Extirpation of the hernial sac. The aponeurosis of the external oblique muscle was incised. The hernial sac was dissected anteromedially from the spermatic
Received August 25, 1998; Accepted November 9, 1998. From the Department of Surgical Gastroenterology, Copenhagen University Hospital, H:S Hvidovre Hospital, Hvidovre, Denmark. Correspondence address: Torben Callesen, MD, H:S Rigshospitalet, HovedOrto-Centret, Anaestesi-og Operationsklinikken, DK 2100 Copenhagen Ø, Denmark. © 1999 by the American College of Surgeons Published by Elsevier Science Inc.
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cord through a slit in the cremasteric muscle and was then ligated and extirpated. Annulorrhaphy. After extirpation of the hernial sac, annulorrhaphy was achieved by tightening of the deep inguinal ring with one or two Prolene 2-0 sutures (Ethicon, Somerville, NJ) between the transverse aponeurotic arch and the iliopubic tract. Modification of Lichtenstein tension-free mesh repair. After extirpation of the hernial sac, a prolene mesh (Ethicon) was fixed by four Prolene 2-0 sutures to the pubic tubercle, to the inguinal ligament, and to the internal oblique aponeurosis; the two “legs” of the mesh were sutured together laterally to the shelving edge of the inguinal ligament. Local anesthesia and analgesia All operations were performed under unmonitored local anesthesia.3 Anesthesia consisted of an inguinal field block and incisional infiltration with bupivacaine 2.5 mg/mL combined with light sedation with midazolam. Perioperative analgesia consisted of oral tenoxicam, 40 mg in the evening and 2 hours before the operation, and 10 mg oral methadone (5 mg in patients older than 60 years) immediately before the operation. The patients received 5 mg methadone orally 8 hours postoperatively and 20 mg/day tenoxicam for 4 days. Paracetamol was recommended at up to 4 g/day for supplementary analgesia. Data sources Data were gathered by a detailed chart review that provided information about physical status and medication obtained during the visit in the outpatient clinic before operation. A detailed, standardized description of the hernia pathology and operation performed was recorded. In addition, a questionnaire was given to the patients after operation to determine pain and wound problems, supplementary use of analgesics, and additional visits to physicians during the first postoperative week. The average pain was scored once a day from the day of operation to the sixth postoperative day on a four-point verbal-rank scale (no, light, moderate, or severe pain). Separate pain scores were obtained during rest, cough, and mobilization (rising to the sitting position). The questionnaire was to be returned in a prestamped return envelope. A second questionnaire with a prestamped return envelope was mailed to the patients 4 weeks after the operation and requested information about pain and satisfaction with local anesthesia and the ambulatory setup. Pain at the end of the fourth postoperative week was scored as described above.
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Data analysis Descriptive statistics were used for demographics characteristics. From each separate set of pain scores (rest, cough, and mobilization), we calculated cumulative pain scores (CPS) over the first week for each patient by adding the following numbers from the daily scores: 0 5 no pain; 1 5 light pain; 2 5 moderate pain; and 3 5 severe pain. All 7 days were weighted equally, so the CPS for a 7-day period ranged from 0 to 21. Cumulative scores were used to avoid repeated comparisons at different time points. The effect parameters were CPS (at rest, cough, and mobilization), 4-week pain scores, and supplementary use of analgesics. Friedman two-way analysis by ranks was used to test for intragroup differences between CPS at rest, coughing, and mobilization. Mann-Whitney U test for unpaired observations for intergroup differences for each scoring condition was used with Bonferroni correction for mass significance; 5% was chosen as the level of significance. Randomization. After intraoperative verification of an indirect hernia, the patients were assigned consecutively to study A (internal ring less than 1.5 cm) or study B (internal ring wider than 1.5 cm). By use of precoded random sequence lists, we allocated the patients in each study to one of the two relevant surgical techniques. Study assignment and random allocation were made by the surgeon. The patients were kept unaware of the surgical technique used until all pain data were recorded. Number of patients. To estimate the necessary number of patients, we assumed a normal distribution of CPS, a two-sided 5% level of significance, a power of 80%, and SD of 4 CPS units. The latter corresponds roughly to an SD of 20 mm in a 100-mm visual analogue scale as found in other studies on postherniorrhaphy pain.1 To detect a difference of 4 CPS units, 16 patients in each group were required.4 Taking into account the possibility of mass significance, the Bonferroni correction was applied, and 2 3 22 patients were calculated as necessary. Because dropouts could not be excluded, 2 3 24 patients were accepted as the necessary number in each study. The frequency of a wide internal inguinal ring was greater than that of a narrow internal ring, and for practical reasons, both studies were continued until 2 3 24 patients were included in study A (narrow); this accounted for the larger groups in study B (wide).
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Table 1. Demographic and Operative Data Study A Characteristic ASA class I II III Age (y) Bupivacaine 0.25% (mL) Midazolam (mg) Operative time (min) Time until discharge (min)
Study B
E (n 5 24)
AE (n 5 24)
AE (n 5 43)
L (n 5 41)
20 4 0 34 (28–44) 50 (44–60) 2.5 (2–3.3) 40 (30–48) 83 (70–109)
17 6 1 32 (26–46) 48 (40–51) 2 (2–3) 35 (30–36) 87 (71–115)
32 9 2 49 (38–60) 48 (41–55) 3 (2–3) 35 (35–50) 100 (70–135)
29 9 3 51 (37–68) 50 (45–56) 2.5 (2–3) 40 (35–50) 85 (70–135)
American Society of Anesthesiologists (ASA) classification is expressed as number of patients. Age, perioperative use of bupivacaine and midazolam, operative time, and time in the ward are expressed as median (interquartile range). AE, sac extirpation plus annulorrhaphy; E, sac extirpation; L, sac extirpation plus modified Lichtenstein’s tension-free mesh repair.
RESULTS Study A Table 1 presents the demographic data, including the American Society of Anesthesiologists classification and operative time. No significant differences were seen between the groups. Forty-five of the 48 patients completed the 1-week questionnaire. One patient had a transient cerebral ischemic attack 3 hours postoperatively and was hospitalized for 1 week with full recovery, and 2 patients never returned the questionnaire despite repeated reminders. Forty-three of 48 patients completed the 4-week questionnaire; 5 patients never returned it despite repeated reminders. There were no significant differences in the median CPS (Fig. 1). The CPS were significantly higher during coughing or mobilization than during rest (p , 0.01) in both groups. Pain scores were highest on day 1 and lowest on day 6 (Fig. 2), with no sig-
nificant difference between groups. Six patients having extirpation of the sac alone and 4 patients having extirpation and annulorrhaphy experienced some pain related to the hernia operation 4 weeks postoperatively. One patient with annulorrhaphy had severe pain during rest but not while coughing or rising, and 1 patient having extirpation alone experienced moderate pain while coughing. Otherwise, all pain was light. No significant differences were seen between the groups (Fig. 2). Nine of 23 patients having annulorrhaphy versus 13 of 22 having extirpation alone used some supplementary analgesics in the first postoperative week (NS). Study B Table 1 shows the demographic data and operative time. No significant differences were seen between the groups. One patient in each group did not return the
Figure 1. Cumulative pain scores (CPS) for the first postoperative week, expressed as median and interquartile range (bars). Study A: extirpation of hernial sac plus annulorrhaphy (AE) versus simple extirpation (E). Study B: extirpation of hernial sac plus annulorrhaphy (AE) versus extirpation plus modified Lichtenstein’s mesh repair (L).
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Figure 2. Study A: extirpation of hernial sac plus annulorrhaphy versus simple extirpation. Pain scores are shown at rest, coughing, and mobilization on day 1, day 6, and at 4 weeks. No significant differences were found between treatment groups at any time point.
questionnaires despite repeated reminders. All other patients returned both questionnaires. There were no significant differences in the median CPS (Fig. 1). The CPS were significantly higher during coughing and mobilization than during rest (p , 0.01) in both groups. Pain scores were highest on day 1 and lowest on day 6 (Fig. 3), with no significant differences between the groups. Eleven of 42 patients having extirpation and annulorrhaphy and 16 of 40 patients having extirpation and Lichtenstein mesh repair experienced some light pain related to the hernia operation 4 weeks postoperatively, and only 1 patient in each group had moderate pain. No patients had severe pain related to the hernia. No significant differences were seen between the groups (Fig. 3). Seventeen of 42 patients having annulorrhaphy versus 18 of 40 having Lichtenstein’s mesh repair used some supplementary analgesics in the first postoperative week (NS). Table 2 shows a post hoc calculation of the risk of overlooking a difference of 4 CPS units in both studies.
DISCUSSION Very little information is available from randomized studies on postoperative pain with different methods of open hernia repair.1,5-7 In contrast, several randomized comparisons have been made between open and laparoscopic repair. The majority showed lower pain scores after laparoscopic repair,1,8-17 and in some of these studies, less pain led to shortened convalescence.1,8,13,15 Open hernia operations are still by far the most common, however, so evaluation of postoperative pain after different open techniques is needed. The main finding in the present study was no difference in pain scorings or use of analgesics between different surgical techniques performed under standardized conditions of anesthesia and analgesia in patients undergoing open repair of a primary indirect inguinal hernia. The theoretical background for study A, comparing simple extirpation of the sac with extirpation plus annulorrhaphy, was that minimized surgical intervention might reduce pain. This concept is supported in part by Smedberg and associates,6 who found less pain after 2 and 6 weeks in patients in
Figure 3. Study B: extirpation of hernial sac plus annulorrhaphy versus extirpation plus modified Lichtenstein’s mesh repair. Pain scores are shown at rest, coughing, and mobilization on day 1, day 6, and at 4 weeks. No significant differences were found between treatment groups at any time point.
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Callesen et al
Table 2. Post Hoc Calculations of the Risk of Overlooking a Difference of 4 Cumulative Pain Score Units Without and with the Bonferroni Correction Pain score category Rest Coughing Mobilization
Study A
Study B
3% (7%) 18% (31%) 8% (17%)
1% (2%) 7% (16%) 3% (8%)
Percentages in parentheses indicate calculations with the Bonferroni correction. Study A, extirpation versus extirpation plus annulorrhaphy; study B, extirpation plus annulorrhaphy versus extirpation plus modified Lichtenstein’s mesh repair.
whom ligation of the hernial sac was omitted compared with those who had ligation of the hernial sac. The present study, however, did not support the concept that less surgical trauma (ie, omission of annulorrhaphy) would result in less pain. The theoretical background for part B of the present study was that reduced tissue tension by implantation of a mesh instead of annulorrhaphy might reduce pain. Use of a tension-free mesh implantation has been advocated because of a favorable pain profile,18 but without sufficient documentation in controlled studies. Only two randomized studies compared Lichtenstein’s mesh repair with Shouldice hernioplasty.5,7 In one well-performed, large-scale study,7 no difference was found between groups in postoperative pain, narcotic use, or time to resume normal activities. The other study5 found less use of analgesics in the group that had Lichtenstein’s mesh repair but 88% of the patients in this group had operations performed under local anesthesia, compared with only 35% that had Shouldice hernioplasty. The local anesthetic provides pain relief for the first postoperative hours, so a marginal difference in the use of analgesics could be explained by the anesthetic rather than by the surgical technique. The present study did not support the hypothesis that a tension-free mesh repair reduces pain after repair of a primary indirect inguinal hernia. Sac extirpation, which was used in all three regimens in the present studies, is generally accepted as an integral part of the surgical treatment of an indirect inguinal hernia, although some surgeons invert the sac into the abdomen without ligation.18 The role of sac extirpation, with or without ligation, with respect to the intensity and duration of postoperative pain is unknown, except for the study by Smedberg and associates,6 who demonstrated less pain without ligation. We conclude that for comparable indirect her-
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nias, the described open surgical techniques have no important differential effects on postoperative pain, and the choice of open surgical technique should not be based on pain considerations. Acknowledgment: This study was supported by a research grant from ASTRA Pain Control, So¨derta¨lje, Sweden, and by quality assurance funds from the Copenhagen Hospital Corporation (H:S). References 1. Callesen T, Kehlet H. Postherniorrhaphy pain. Anesthesiology 1997;87:1219–1230. 2. Callesen T, Bech K, Kehlet H. The feasibility, safety and cost of infiltration anaesthesia for hernia repair. Anaesthesia 1998; 53:31–35. 3. Amid PK, Shulman AG, Lichtenstein IL. Local anesthesia for inguinal hernia repair step-by-step procedure. Ann Surg 1994; 220:735–737. 4. Young MJ, Bresnitz EA, Strom BL. Sample size nomograms for interpreting negative clinical trials. Ann Intern Med 1983; 99:248–251. 5. Kux M, Fuchsja¨ger N, Feichter A. Lichtenstein-Patch versus Shouldice-Technik bei prima¨ren Leistenhernien mit hoher Rezidivgefa¨hrdung. Chirurg 1994;65:59–62. 6. Smedberg SGG, Broome´ AEA, Gullmo A. Ligation of the hernial sac? Surg Clin North Am 1984;64:299–306. 7. Barth RJ, Burchard KW, Tosteson A, et al. Short-term outcome after mesh or Shouldice herniorrhaphy: a randomized prospective study. Surgery 1998;123:121–126. 8. Lawrence K, McWhinnie D, Goodwin A, et al. Randomised controlled trial of laparoscopic versus open repair of inguinal hernia: early results. BMJ 1995;311:981–985. 9. Stoker DL, Spiegelhalter DJ, Singh R, Wellwood JM. Laparoscopic versus open inguinal hernia repair: randomised prospective trial. Lancet 1994;343:1243–1245. 10. Maddern GJ, Rudkin G, Bessell JR, et al. A comparison of laparoscopic and open hernia repair as a day surgical procedure. Surg Endosc 1994;8:1404–1408. 11. Barkun JS, Wexler MJ, Hinchey EJ, et al. Laparoscopic versus open inguinal herniorrhaphy: preliminary results of a randomized controlled trial. Surgery 1995;118:703–710. 12. Rudkin GE, Maddern GJ. Peri-operative outcome for day-case laparoscopic and open inguinal hernia repair. Anaesthesia 1995; 50:586–589. 13. Payne JH, Grininger LM, Izawa MT, et al. Laparoscopic or open inguinal herniorrhaphy? Arch Surg 1994;129:973–981. 14. Tschudi J, Wagner M, Klaiber C, et al. Controlled multicenter trial of laparoscopic transabdominal preperitoneal hernioplasty vs Shouldice herniorrhaphy. Surg Endosc 1996;10:845–847. 15. Leibl B, Da¨ubler P, Schwarz J, et al. Standardisierte laparoskopische Hernioplastik vs. Shouldice-Reparation. Ergebnisse einer randomisierten Vergleichsstudie. Chirurg 1995;66:895–898. 16. Filipi CJ, Gaston-Johansson F, McBride PJ, et al. An assessment of pain and return to normal activity: laparoscopic herniorrhaphy vs open tension-free Lichtenstein repair. Surg Endosc 1996; 10:983–986. 17. Schrenk P, Woisetschla¨ger R, Rieger R, Wayand W. Prospective randomized trial comparing postoperative pain and return to physical activity after transabdominal preperitoneal, total preperitoneal or Shouldice technique for inguinal hernia repair. Br J Surg 1996;83:1563–1566. 18. Amid PK, Shulman AG, Lichtenstein IL. Open “tension-free” repair of inguinal hernias: the Lichtenstein technique. Eur J Surg 1996;162:447–453.