Anesth Analg 2006;102:1480-1484
© 2006 International Anesthesia Research Society
doi: 10.1213/01.ane.0000204321.85599.0d
PAIN MEDICINE
Laparoscopic Versus Open Myomectomy: A Double-Blind Study to Evaluate Postoperative Pain
A. Holzer, MD*,
S. T. Jirecek, MD
,
U. M. Illievich, MD*,
J. Huber, MD, and
R. J. Wenzl, MD
Departments of *Anaesthesiology and General Intensive Care Medicine and Obstetrics and Gynecology; Medical University of Vienna, Austria
Address correspondence and reprint requests to Rene Wenzl, MD, Department of Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Address e-mail to rene.wenzl{at}meduniwien.ac.at.
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Abstract
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The advantages of laparoscopic over open surgery have been documented in nonblinded settings. Our prospective, double-blind setting evaluated pain scores 72 h after surgery by comparing patients who underwent laparoscopic myomectomy or with laparotomy. Forty women referred for conservative myomectomy were included in the study. After stratification (myoma size, number of myomas, and surgeon), patients were randomized to either laparoscopy (n = 19) or laparotomy (n = 21) and received a standardized anesthesia and patient-controlled analgesia for 24 h after surgery. Identical wound dressings were applied to blind the patient and the observer to the surgical approach. The postoperative pain scores were documented on a visual analog scale (VAS; 0 = no and 10 = unbearable pain) at 24, 48, and 72 h after surgery. As the primary outcome variable, we calculated the mean overall VAS-score at these time points. P < 0.05 (t-test and analysis of covariance) was considered statistically significant. There were no differences in patient characteristics among the groups. The mean overall VAS score at 24, 48, and72 h was statistically significantly lower in the laparoscopic group compared with the laparotomy group (2.28 ± 1.38 versus 4.03 ± 1.63; P < 0.01). Our data demonstrate, for the first time in a double-blind setting, that laparoscopic myomectomy reduces postoperative pain for 72 h after surgery compared with laparotomy.
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Introduction
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Several indications and diseases in gynecology can be managed via laparoscopic surgery. Published reports have documented the advantages of laparoscopy over open surgery in nonblinded settings. The benefits of laparoscopic surgery claimed from these studies include a short hospital stay, a better cosmetic effect, less expensive, and decreased postoperative pain (1–5).
Myomas are the most common uterine neoplasm (2). Particularly for women who want to preserve their uterus and their childbearing potential, myomectomy without removal of the whole uterus is mandatory if surgery is required. The indications for surgery include symptomatic myomas that cause infertility, abortion, abnormal uterine bleeding, pain, or rapidly growing myomas, even if asymptomatic, especially after menopause (2). Some studies have documented the possible advantages of the laparoscopic approach for these indications (2,6–9). In addition, a prospective, randomized, nonblinded trial showed that laparoscopic myomectomy might offer the benefits of decreased postoperative pain and shorter recovery time compared with laparotomy (2).
All previous studies that have documented the benefits of the laparoscopic approach in gynecology were nonblinded studies, with the potential for bias with regard to expectations concerning the individual attitudes of both physicians and patients. It was the aim of our prospective, randomized, double-blind trial to evaluate pain scores for the 72 postoperative h in patients randomly assigned to myomectomy with either laparoscopy or open surgery.
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Methods
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For our study, we included women, 19–45 yr old, who were referred for myomectomy of symptomatic myomas. Women were eligible for our double-blind study of conservative myomectomy if the operation could be performed via the laparoscopic approach. Inclusion criteria were intramural myomas, a 3- to 10-cm in diameter size for the largest myoma, and an ASA physical status of I–III. We excluded all patients with contraindications to general anesthesia, an ASA physical status of IV or V, all pregnant patients, and all women who were unable to understand the study or give informed consent. The local IRB approved the protocol. After written and verbal informed consent, 40 patients entered the study. Patient characteristics and indications for operation are shown in Table 1.
The patients were assigned by computer-generated randomization to either laparotomy (n = 21) or laparoscopy (n = 19) when the patients were already in the operating room (central telephone). Before randomization, patients were stratified according to the size of the largest myoma, the additive diameter of all myomas, and the individual surgeon who would perform the operation.
All surgical procedures were performed by or under the supervision of a staff member from the Department of Obstetrics and Gynecology, Medical University of Vienna, Austria. No patient had received hormonal therapy for myomas before the operation. We used a standardized anesthesia protocol in both groups. All patients were premedicated with midazolam 7.5 mg orally 1 h before the operation. For the induction of anesthesia, we administered 0.003 mg/kg body weight (BW) of fentanyl, a maximum dose of 3 mg/kg BW of propofol, and 0.1 mg/kg BW of vecuronium to facilitate endotracheal intubation. Anesthesia was maintained with a continuous infusion of propofol (5 mg · kg BW–1 · h–1) and fentanyl as determined by the anesthesia provider. All patients' lungs were ventilated conventionally. Nitrous oxide was avoided. The operative technique was performed for laparotomy and laparoscopy, as previously described by Mais et al. (2). In contrast to that study, we used 10 mL of bupivacaine 0.5% for incision instillation in all patients (laparoscopy and laparotomy) after surgery. In addition, we recorded the duration of the operation, blood loss, and the difference in hematocrit (before and 24 h after surgery).
After surgery, identical wound dressings were applied in both groups, with neither the patient nor the observer who recorded the postoperative pain aware of the surgical approach (Fig. 1). All patients had drains inserted for 24 h after surgery in the lateral port or at the possible site of a lateral port in open surgery. This ensured that other wound dressings were not removed when drains were removed 24 h after surgery (10). For analgesia, we offered a patient-controlled (PCA) system for 24 h after the operation. Patients were allowed a maximum of 4 doses of piritramide (0.05 mg · kg BW–1 · h–1). The numbers of doses of piritramide were recorded for each patient. After 24 h after surgery, subcutaneous injections of 7.5 mg of piritramide were given if requested by the patient. No additional analgesics were allowed during the study period. Oral intake was allowed after 24 h. If there was no bowel movement within 48 h, laxatives were administered orally.
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Figure 1. After surgery, identical wound dressings were applied in both groups for 72 h, leaving the patient and the observer who recorded the postoperative pain scores unaware of the surgical approach.
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The intensity of postoperative pain was documented by a visual analog scale (VAS) score. The VAS scale was an unlabeled 10-cm horizontal line with word anchors at each end, ranging from 0 = "no pain at all" to 10 = "pain as bad as it could be." The patients were asked to make a mark on the line representing the maximum pain intensity suffered since the last scoring. This mark was converted to distance in centimeters from the "no pain" anchor to give a pain score that could range from 0 to 10 cm (2). These pain scores were taken 24, 48, and 72 h after surgery. As the primary outcome variable, we calculated the mean pain score from these 3 measurements, which represented the average pain score over the first 3 postoperative days. After documentation of the VAS 72 h after surgery, the dressings were removed.
Patients were allowed to leave the hospital whenever they wanted but not before 72 h, in any case. We recorded patient comfort before the operation 1 and 4 wk after the operation by VAS and the time when patients were able to fully return to work.
For sample size calculation, we referred to the data of Mais et al. (2). A sample size of 40 patients provides a power of 90% to detect a difference of 1.7 (on a scale of 0–10) in the mean overall VAS scores between the 2 groups. Variables of interest (normal distribution) are described by mean and sd and all others by median and range. For statistical analysis of all data with normal distribution, a t-test was applied. Additionally, analysis of covariance (ANCOVA) was performed to adjust P-values for the diameter of the largest myoma, additive diameter of myomas, and number of enucleated myomas. If data were not normally distributed, a Mann-Whitney U-test was applied. All reported P-values are the result of two-sided tests. A P-value equal to or <0.05 was considered statistically significant.
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Results
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Randomization produced two groups with similar characteristics (Table 1). There were no intraoperative complications in either group. No patient in the laparoscopic group had to be converted to open surgery because of intraoperative difficulties. Therefore, we were able to perform a per-protocol analysis. The postoperative course was uneventful in all patients. The preoperative ultrasonographic and intraoperative visual diagnoses were confirmed by histological evaluation in all patients. Mean age, body mass index, number of myomas, maximum myoma diameter, and additive myoma diameter were similar in both groups (Table 1). Our main outcome variable (mean overall VAS score of 24, 48, and 72 h after surgery) was statistically significantly lower in the laparoscopic group compared with open surgery (Table 1). In the laparoscopic group, the VAS score (24, 48, and 72 h) was 2.28 ± 1.38, whereas in the open surgery group, the patients had a VAS score of 4.03 ± 1.63 (t-test and ANCOVA; P < 0.01) (Table 1; Fig. 2). The VAS scores at 24, 48, and 72 h in both groups are demonstrated in Figure 3.
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Figure 2. Mean overall visual analog scale (VAS) score (24, 48, and 72 h after surgery) in the laparoscopic group was statistically significantly lower compared with the laparotomy group (2.28 ± 1.38 versus 4.03 ± 1.63; t-test; P = 0.0008). The top, bottom, and line through the middle of the box correspond to the 75th percentile (top quartile), the 25th percentile (bottom quartile), and the 50th percentile (median), respectively. The whiskers on the bottom extend from the 10th percentile (bottom decile) and top 90th percentile (top decile). * Statistically significant difference between the groups, P < 0.05, t test.
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Figure 3. Visual analog scale (VAS) scores before surgery and 24, 48, 72 h, 1 wk, and 4 wk after surgery. * Statistically significant difference between the groups, P < 0.05, t test.
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With regard to pain medication, patients in the open surgery group consumed more boli of piritramide (PCA) during the first 24 h after surgery compared with patients in the laparoscopic group (12 [2–90] versus 7 [0–23]; Table 1; Fig. 4).
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Figure 4. Piritramide boli during the first 24 h. Boli were statistically significantly smaller in the laparoscopy group compared with the laparotomy group (7 [0–23] versus 12 [2–90]; Mann-Whitney U-test; P = 0.03). The top, bottom, and line through the middle of the box correspond to the 75th percentile (top quartile), the 25th percentile (bottom quartile), and the 50th percentile (median), respectively. The whiskers on the bottom extend from the 10th percentile (bottom decile) and top 90th percentile (top decile). * Statistically significant difference between the groups, P < 0.05, Mann-Whitney U test.
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Discussion
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This is the first report of a double-blind, prospective, randomized trial comparing laparoscopy and laparotomy in a gynecological procedure. In addition, it is the first double-blind study to demonstrate and confirm that laparoscopy results in lower pain scores after surgery compared with open surgery.
For cholecystectomy, it has been demonstrated, in a single-blind setting, that the laparoscopic approach takes longer than small-incision surgery and does not have any significant advantages in terms of hospital stay or postoperative recovery (10). In addition, laparoscopic fundoplication was associated with a longer operating time, better respiratory function, less need for analgesics, and a shorter hospital stay, whereas no reduction in the duration of postoperative sick leave was found compared with open surgery (4). A recent nonblinded study evaluating hernia mesh repair demonstrated less postoperative pain and earlier return to work in the laparoscopic group. With regard to recurrence of hernias and perioperative complications, the open technique was superior to the laparoscopic technique (11). Ignacio et al. (12) reported no difference between laparoscopic and open appendectomy in a prospective, double-blind setting. However, the patients were all men, and the blinding for the patients was removed within 24 hours after surgery.
For operations with small incisions at open surgery, such as cholecystectomy and appendectomy, a laparoscopic approach does not seem to result in the same benefit as for operations where larger incisions are required. For myomectomy, however, especially for large intramural myomas, a rather long transversal incision is required in open surgery; thus, laparoscopy results in an advantage with regard to postoperative pain (2). Moreover, laparoscopy is favorable because of the cosmetic benefit. However, this study was performed in a nonblinded setting in a center specializing in laparoscopic surgery. Therefore, there could have been a bias regarding patients' and surgeons' attitudes and implications. In our study, with a double-blind setting, we tried to exclude all these factors. Patients in the laparoscopic group had statistically significant lower mean overall VAS scores (24, 48, and 72 hours after surgery) compared with the laparotomy group. When comparing VAS scores at 24 hours, there was no statistically significant difference between the groups. However, during this time, all patients had a PCA system. The consumed boli of piritramide were statistically significantly larger in the laparotomy group. Considering 48 and 72 hours after surgery, the VAS scores were statistically significantly lower in the laparoscopic group.
Preoperatively, the VAS score was evaluated for all patients. The patients in the laparoscopic group had a higher VAS (more pain) compared with the patients in the laparotomy group, but patients in the laparoscopic group had less pain after surgery. VAS scores after 1 and 4 wk after surgery did not show any difference between the groups. Return to work was earlier in the laparoscopic group, but this factor did not reach statistical significance. Operating time was statistically significantly longer in the laparoscopic group, whereas blood loss was statistically significantly larger in the laparotomy group. However, we believe that both differences in operating time and in blood loss were not clinically relevant. No patient in either group required any blood transfusion.
Earlier studies suggest that laparoscopic myomectomy should be reserved for patients with less than four myomas and a diameter of <7 cm for the largest myoma (13). Careful patient selection can avoid complications and the need to convert to laparotomy (2,13,14). In our study, the largest diameter of a myoma was 10 cm in the laparoscopic group, and no operation had to be converted to laparotomy. These results were expected, because with advanced skills and technique, larger myomas can be treated by minimal access surgery (15).
In conclusion, our data confirm that, in a double-blind setting, laparoscopic surgery reduces postoperative pain and analgesic demand in myomectomy during the first 3 days after surgery compared with open surgery.
We want to thank Harald Heinzl, PhD, Department of Medical Computer Sciences, Section of Clinical Biometrics, Medical University of Vienna, for his valuable statistical advises.
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Footnotes
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Accepted for publication January 4, 2006.
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Abstract
Introduction
