The effect of transversus abdominis plane block application on postoperative analgesia quality and patient satisfaction after varicocele surgery: a randomized clinical trial

Approval for the study was granted by the Kahramanmaras Sutcu Imam University Faculty of Medicine Clinical Research Ethical Committee (dated February 22, 2016; session No. 2016/04; decision No. 15), and all procedures were drafted in accordance with principles of the Helsinki Declaration. This blind, randomized, prospective, and controlled study was conducted in the urology and anesthesiology departments of Kahramanmaras Sutcu Imam University Hospital, between October 2016 and July 2018. The patients comprised in the study were informed about the methods before the procedure and written consent forms were obtained. A Clinical Trials number (ClinicalTrials.gov ID: NCT02983383) was also obtained before the study.

The study included a total of 70 consecutive patients, aged 18–45 years, evaluated as American Society of Anesthesiologists (ASA) I–II who underwent elective varicocele operations. Patients with a psychiatric disorder, usage of opioid analgesics, tricyclic antidepressants, or corticosteroids, hypersensitivity, severe systemic disorders such as cardiovascular, liver, and kidney disease, a drug and chronic pain killer addiction, anesthetic substance usage, alcohol addiction, pain syndrome, coagulopathy, infection in the surgical site, or recurrent varicocele were excluded from the study. The patients were randomly separated with the lottery method (specifically, the ball-pick method) into two groups, as the spinal anesthesia + TAP block group (TAP block, n = 34) and the spinal anesthesia + intrathecal morphine (ITM) group (ITM, n = 36).

Sample size calculation

The approximate sample size was calculated using the G*Power 3.1.9.4 analysis program (Heinrich-Heine-Universitat). We sought to investigate the analgesic efficiency of the USG-TAP block used for varicocele surgeries. The power analysis was based on the mean postoperative analgesia consumption. The sample size estimation was based on the postoperative tradamol requirements (control group: 309.6 ± 90.1; USG-TAP block: 234.0 ± 135.9) of a similar study performed by Kupiec et al. [15]. The sample size was calculated at a power of 85% and a significance level of 5%, and it was determined that it would be necessary to have approximately 34 patients per group to obtain significant statistical value. To be most conservative, a total of 70 patients were included in the research, with 34 patients in the treatment group and 36 patients in the control group (Figure 1).

Figure 1.

The mean age of the patients was 32.5 ± 6.5 years in the TAP block group (n = 34), and 30.1 ± 5.6 years (n = 36) in the spinal anesthesia group, and mean BMI values were 26.7 ± 3.9 and 23.1 ± 2.7, respectively. There was no statistical difference between the groups in respect of these parameters. Although the operation time in the spinal anesthesia group was shorter, the difference was not statistically significant (P = 0.174; Table 1). One patient in both groups avoided movement due to pain (P = 0.731), 4 patients in the TAP block group responded negatively, and 3 patients in the ITM group felt pain (P = 0.450). Tiredness after surgery was reported by 3 patients in the TAP block group and in 10 patients in the ITM group (P = 0.045). In our study, it was observed that VAS scores increased significantly in both groups over time [F (3, 37, 268) = 264.76; P < 0.001; η² = 0.798], but the difference between the groups was not significant [F (3, 37, 268) = 1.40; P = 0.233; η² = 0.021] (Figure 2).

Figure 2.

There was a statistically significant difference between the groups in terms of patient satisfaction scores (P = 0.019). The results were significantly different in the spinal anesthesia group in terms of anesthesia complications (P = 0.023; Table 1).

When patients were evaluated in respect of patient-controlled pain monitoring, one patient in both groups used additional painkillers.

In the TAP block group, 1 patient who underwent bilateral varicocelectomy and bilateral TAP block first needed analgesia of 150 mg tramadol at 4 h postoperatively. The patient stated that he felt unilateral pain, which suggested unilateral unsuccessful block implementation. In the ITM group, analgesia requirement was found to be 75 mg tramadol at 10 h postoperatively. There was no statistically significant difference between the groups in terms of postoperative analgesic requirement (P = 0.751). When the patients were assessed in terms of factors affecting postoperative patient satisfaction, it was seen that feeling fatigue after surgery (r = −0.505, P < 0.001) and complications such as nausea, vomiting, and itching in the postoperative period (r = −0.831, P = 0.001) were found to have a negative effect on patient satisfaction. In the subgroup analysis, especially nausea (r = −0. 413, P = 0.001) and vomiting (r = −0. 355, P = 0.003) were found to have a greater effect than itching (r = −0. 295, P = 0.013) on patient satisfaction.

When the patients were evaluated as patients with and without complications, there was no statistically significant difference in terms of VAS values at 0 h, 2 h, 6 h, 12 h, and 18 h (respectively, P = 0.342, P = 0.745, P = 0.054, P = 0.304, and P = 0.139). Patient satisfaction was found to be statistically significantly lower in patients with complications (nausea, vomiting, and itching) (P = 0.001). The VAS scores and patient satisfaction are shown in Figure 3.

Figure 3.

When the patients were grouped as patients with and without drowsiness-fatigue associated with patient satisfaction, the VAS values were lower in patients with drowsiness-fatigue, which was not statistically significant (all P > 0.05), and patient satisfaction was significantly higher in patients without drowsiness-fatigue (P = 0.001; Figure 4).

Figure 4.

In this study, we evaluated the effects of TAP block application on patient satisfaction by comparing with ITM application in postoperative analgesia control in patients who underwent elective varicocelectomy operations. For this purpose, objective evaluation was made at 24 h postoperatively using the QUIPS test. The study results showed that postoperative fatigue and some complications such as nausea, vomiting, and pruritus were found to be highly associated with patient satisfaction, but not BMI.

To our knowledge, this is the first study to have evaluated the effect of TAP block on patient satisfaction. Although the effects of TAP block application on postoperative analgesic consumption and analgesic quality were evaluated in this study using a procedure similar to those employed in previous studies, there was additional evaluation of the effects of TAP block application on postoperative patient satisfaction on the 1st postoperative day using the QUIPS test, which was first used in 2005.

Varicocele is the most common pathology of male infertility, which can be seen in 15%–22% of the adult male population [16]. Although it is treated with laparoscopic or radiological (sclerotherapy or embolization) methods, open surgery is still the gold standard application [17]. In terms of anesthesia approaches, general, local, or regional anesthetic methods can be used for varicocele operations. Although local or regional approaches have some advantages such as low postoperative nausea and vomiting, suppression of stress response to surgical intervention, reduction of morbidity in high-risk patients, continuation of the analgesic effect in the postoperative period, and fast recovery without respiratory depression or loss of consciousness, there are also some disadvantages such as arterial vasodilatation, peripheral reflex vasoconstriction, bradycardia, and hypotension, which are specific to the cardiovascular system, and urinary retention [18]. In contrast, while there are some adverse effects of general anesthesia such as nausea, vomiting, pain, and respiratory depression, it has the advantages of minimal urinary retention, and better control of hemodynamic parameters both intraoperatively and postoperatively [19]. However, postoperative pain management, which determines patient satisfaction, is an important aspect of anesthetic care and the generally recommended multimodal analgesic techniques have been widely used in varicocele surgery in recent years.

There are many studies in literature that have evaluated the effect of TAP block on postoperative pain control after different surgical procedures or have compared TAP block or other multimodal analgesic methods [7,8,9,10,11,12].

There are also two different studies that have evaluated the efficacy of TAP block after varicocelectomy as in the current study. The efficacies of conventional spinal anesthesia and TAP block were compared in patients undergoing retroperitoneal varicocelectomy in the first study and it was reported that the anesthetic efficacy of the TAP block method was similar to that of spinal anesthesia. The VAS values of both methods were similar in the postoperative period [20]. In the other study, morphine and TAP block were compared in patients undergoing varicocelectomy with general anesthesia in terms of postoperative pain control and both methods were found to have similar effects on pain control, but TAP block application was found to be significantly superior in terms of some somatic effects such as nausea, vomiting, and itching [21].

In the present study, the QUIPS test was applied at 24 h postoperatively. The most important limitation of this test is that it provides only one measurement for pain and does not include the whole 24 h period [22]. To overcome this, VAS values were taken at 0 h, 6 h, 12 h, and 18 h to ensure that optimal evaluation of the pain process was performed. No difference in VAS values was determined between the groups (Figure 2). In addition, the pain values obtained throughout the first 24 h postoperative period were evaluated as mean pain value throughout 24 h, and maximum and minimum pain values. There were no statistically significant differences between the groups in terms of these values. It is known that respiratory functions are affected and the cough reflex is suppressed due to severe postoperative pain, which is particularly prone to complications such as atelectasis. As some authors have stated, optimal pain control is not only a factor that may shorten hospital stay but also affects surgical outcomes in the postoperative period by preventing some lung complications such as atelectasis [23, 24]. Pain felt on respiration or coughing in the postoperative period was reported by 11.8% of the TAP group and by 6.5% of the ITM group, but there was no significant difference between the groups (P = 0.450). In addition, none of the patients in the present study developed AC complication, postoperatively. Nevertheless, considering that the operation site chosen in the present study was the lower abdominal region, we infer that further studies are needed to evaluate the effect of TAP block on respiratory complications in abdominal surgery.

Although the ITM application is known to have highly effective analgesic efficacy, it has severe potential side effects [25,26,27]. Therefore, it is not preferred for postoperative analgesia, and analgesic regimens with a lower side-effect profile are generally preferred. In the present study, although the analgesic activity was good in the ITM group, patient satisfaction was found to be negatively affected in patients with morphine side effects. Correlation analysis revealed that the most effective factors on postoperative patient satisfaction were postoperative fatigue and dizziness (r = −0.811, P = 0.001). When the patients were separated as those with and without fatigue-drowsiness, the mean pain, maximum pain, and minimum pain values in patients with fatigue-drowsiness were lower than those of the patients without fatigue-drowsiness, but this difference was not statistically significant (P = 0.483, P = 0.175, P = 0.714).

Although there were fewer patients who did not feel fatigue-drowsiness postoperatively, the difference was not statistically significant (P = 0.483, P = 0.175, P = 0.714). Despite the lack of a statistically significant difference, the feeling of drowsiness was seen to be more disturbing to the patients in terms of satisfaction. Similar results were found for nausea, vomiting, and itching. In the subgroup analysis, especially nausea (r = −0.576, P = 0.001) and vomiting (r = −0.541, P = 0.001) had a greater effect on patient satisfaction than itching (r = −0.348, P = 0.003). Since we could not access data on this issue from the literature, we could not compare our study results with those of any previous study.

No vascular complications related to the TAP block developed in the current study. Therefore, the main limitation of the study was that no evaluation was made of the effect of such complications on patient satisfaction.

In conclusion, due to low complication rates, TAP block is an effective application for postoperative analgesia management in varicocele operations that increases patient satisfaction postoperatively.