|Year : 2018 | Volume
| Issue : 1 | Page : 23-28
The value of adding ketamine to lidocaine and bupivacaine mixture in ultrasonic-guided spermatic cord block in scrotal surgery: a randomized double-blind prospective study
Mostafa M Shaheen, Nadia H Fattouh, Ayman A Yousef, Ahmed A Shama
Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Tanta University, Tanta, Egypt
|Date of Submission||01-Jul-2017|
|Date of Acceptance||20-Jan-2018|
|Date of Web Publication||26-Jul-2018|
Mostafa M Shaheen
El Nagshy Street Tanta Gharbia, 31511
Background Spermatic cord block for scrotal surgery avoids the potential risks of neuraxial and general anesthesia and provides long-lasting postoperative analgesia.
Aim The aim of this study is to evaluate the value of adding ketamine to lidocaine-bupivacaine mixture for ultrasonic-guided spermatic cord block for patients undergoing scrotal surgery.
Patients and methods This study was carried out in Tanta University Hospitals on 50 patients with ASA physical status I and II, age older than or equal to 18 years, who were scheduled for elective scrotal surgery. Patients were randomly allocated into two equal groups using sealed envelopes: 25 patients received ultrasound-guided spermatic cord block by a mixture of lidocaine 5 ml (2%), plain bupivacaine 5 ml (0.5%), and 1-ml normal saline (group 1), and 25 patients received ultrasound-guided spermatic cord block by a mixture of lidocaine 5 ml (2%), plain bupivacaine 5 ml (0.5%), and ketamine (0.5 mg/kg) (group 2).
Results There was no significant difference between the demographic data, patient characteristics, heart rate, mean arterial blood pressure, and oxygen saturation in the studied groups. There was significantly rapid onset and prolonged duration of blockade in group 2 and significant increase in visual analog scale score in group 1 at 6 h postoperatively, whereas a significant increase occurred in group 2 at 12 h, postoperatively. There was significant increase in group 1 regarding the amount of rescue analgesia.
Conclusion In ultrasound-guided spermatic cord block in scrotal surgery, addition of (0.5 mg/kg) ketamine to lidocaine–bupivacaine mixture improves onset of the block, prolongs postoperative analgesia, and reduces the consumption of postoperative rescue analgesics.
Keywords: ketamine, Scortal surgery, ultrasound spermatic cord block
|How to cite this article:|
Shaheen MM, Fattouh NH, Yousef AA, Shama AA. The value of adding ketamine to lidocaine and bupivacaine mixture in ultrasonic-guided spermatic cord block in scrotal surgery: a randomized double-blind prospective study. Tanta Med J 2018;46:23-8
|How to cite this URL:|
Shaheen MM, Fattouh NH, Yousef AA, Shama AA. The value of adding ketamine to lidocaine and bupivacaine mixture in ultrasonic-guided spermatic cord block in scrotal surgery: a randomized double-blind prospective study. Tanta Med J [serial online] 2018 [cited 2019 Feb 22];46:23-8. Available from: http://www.tdj.eg.net/text.asp?2018/46/1/23/237622
| Introduction|| |
Spermatic cord block for scrotal surgery overcomes the risks of neuraxial and general anesthesia and offers long period of postoperative analgesia . Many inguino-scrotal procedures in the adults can be done under local anesthesia. These procedures include simple inguinal hernia repair, inguinal lymph node biopsy, hydrocelectomy, testicular biopsy, testicular fixation, orchidectomy, and scrotal exploration .
Adjuvants are usually added to local anesthetic so as to enhance the quality and prolong the period of peripheral nerve blockade, without producing adverse effects associated with the systemic use of these additives, such as hypotension, bradycardia respiratory depression, sedation, hallucinations, nausea, vomiting, itching, or urinary retention .
Ketamine had been used as an adjuvant in peripheral nerve block owing to its action on N-methyl-d-aspartate (NMDA) receptors. Ketamine has been considered to be mainly a noncompetitive antagonist of the NMDA receptors .
Our study hypothesis is to evaluate the value of adding ketamine to lidocaine–bupivacaine mixture for ultrasonic-guided spermatic cord block for patients undergoing scrotal surgery.
| Patients and methods|| |
This study was carried out in Tanta University Hospitals on 50 patients scheduled for elective scrotal surgery. All patients received an explanation to the purpose of the study, and written informed consent was taken from each patient participating in the study. Patients with ASA physical status I and II, age older than or equal to 18 years, scheduled for undergoing elective scrotal surgery were included in the study. Patient who refused regional anesthesia, were morbidly obese with a BMI over 40, had blood coagulation abnormalities such as international normalized ratio of more than 1.5 or platelet count under 10×103, had allergy to the given drug, had uncontrolled concomitant medical conditions, and had local infection at the site of injection were excluded from the study. Patients were randomly allocated into two equal groups using sealed envelopes. A total of 25 patients received ultrasound-guided spermatic cord block by a mixture of lidocaine 5 ml (2%), plain bupivacaine 5 ml (0.5%), and 1-ml normal saline (group 1), and 25 patients received ultrasound-guided spermatic cord block by a mixture of lidocaine 5 ml (2%), plain bupivacaine 5 ml (0.5%), and ketamine (0.5 mg/kg) (group 2).
Routine laboratory investigations were performed, including complete blood count, prothrombin time and activity, and liver (serum glutamate pyruvate transaminase, serum glutamic-oxaloacetic transaminase, total bilirubin, and serum albumin) and renal function (urea and creatinine) tests. Intravenous access was obtained using peripheral 18-G cannula. Routine monitoring of heart rate (HR) by ECG, mean arterial blood pressure (MAP) using noninvasive blood pressure, and peripheral oxygen saturation (SPO2) using pulse oximeter had been performed. Administration of an intravenous bolus of midazolam (0.01 mg/kg) was given to all patients before surgery.
The groin region was shaved and sterilized, and the site of incision on the skin was infiltrated by 5-ml lidocaine. The spermatic cord and its contents were visualized by ultrasound (Sonoscape SSI6000, Sonoscape Company Ltd, Shenzen, China) using a linear-array transducer with high frequency of 12 MHz at the ispilateral inguino-scrotal junction distal to the external ring of the inguinal canal, and then the studied drugs were injected in both groups.
Approach to the spermatic cord block
The four-hand technique is done by pulling the cord gently to the surface to visualize the anatomical structures. The testicular artery was first identified by Doppler ultrasound. The deferent duct was identified as a round noncompressible structure with no Doppler flow signal. A 22-G needle was inserted under out-of-plane real-time monitoring with the spermatic cord in short-axis view and directed toward the deferent duct, contralaterally to the testicular artery. The needle was advanced toward the deferent duct. It is better to visualize the local anesthetic diffusion around the deferent duct ([Figure 2] and [Figure 3]).
Demographic data including age, weight, duration of surgery and type of surgery, MAP, HR, and SpO2 were recorded. Onset of spermatic cord block was recorded. Postoperative pain was assessed using visual analog scale (VAS; 0=no pain and 10=worst possible pain). Duration of the block and number of patients who needed postoperative rescue analgesia were also recorded.
Parametric data were analyzed using Student’s t-test, whereas nonparametric data were analyzed using χ2 tests. Data were presented as mean and SD. A P value of less than 0.05 was considered significant.
Sample size analysis
Sample size analysis indicated that 25 patients per group were needed to achieve 95% confidence interval limit, 80% power of analysis, and allocation ratio 1 : 1 at 5% significant level with reduction of morphine consumption from 30 to 5%.
| Results|| |
A total of 50 patients were randomly allocated into two equal groups: group 1 received ultrasound-guided spermatic cord by a mixture of lidocaine–bupivacaine and 1-ml normal saline, and group 2 received ultrasound-guided spermatic cord by ketamine in addition to lidocaine–bupivacine mixture. Patients with failed technique (dropped out) owing to technical problems (two in group 1 and one in group 2) did not complete the study. Therefore, 23 patients in group 1 and 24 patients in group 2 were included ([Figure 1]).
|Figure 2 Placement of linear probe on spermatic cord and needle insertion 1 cm lateral to probe.|
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|Figure 3 Ultrasongraphic appearance of spermatic cord with its contents.|
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There was no significant difference between the demographic data including age, weight, and type of surgery in the studied groups ([Table 1]).
There was no significant difference in HR mean value between both groups throughout the perioperative period. There was no significant difference in MAP between both groups throughout the perioperative period ([Table 2] and [Table 3]).
|Table 2 Comparison of heart rate changes in the studied groups (beats/min)|
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|Table 3 Comparison of mean arterial blood pressure changes in the studied groups (mmHg)|
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The onset of spermatic cord block was significantly rapid in group 2. In group 1, the mean value of onset of the block was 12.17±2.53 min, whereas in group 2, it was 8.29±2.74 min (P=0.001)
The duration of the block was 735.00±420.27 min. There was significant prolonged duration of blockade in group 2 (P=0.0005) ([Table 4]).
The VAS mean value in group 1 was 1.17±1.27, 2.09±1.59, 4.87±2.01, 0.91±1.41, 1.52±1.73, and 1.78±1.59 at time 0, 2, 6, 12, 18, and 24 h, respectively. There was significant increase in VAS at 6 h postoperatively compared with preoperative mean value (P=0.001). In group 2, VAS mean value was 0.79±0.72, 1.46±1.28, 1.58±1.21, 4.50±2.17, 1.29±1.60, and 1.50±1.25 at preoperative, 2, 6, 12, 18, and 24 h, respectively. There was significant increase in VAS at 12 h compared with preoperative mean value (P=0.001) ([Table 5]).
There was significant increase in group 1 regarding the amount of rescue analgesia of morphine needed (P=0.001). Total morphine consumption in group 1 was 90 mg, with a mean value of 3.91±1.41 mg, whereas in group 2, it was 57 mg, with a mean value of 2.38±1.53 mg. A significantly higher number of patients in group 1 required rescue analgesia, with 23 (100%) patients, compared with only six (25%) patients in group 2 (P=0.001) ([Table 6]).
| Discussion|| |
Patients receiving ultrasound-guided spermatic cord block using mixture of lidocaine–bupivacaine–ketamine showed a significant relief of postoperative pain as indicated by the lower values of VAS and the significantly lower need for postoperative rescue analgesia.
We claim that our results are because of the local effects of ketamine. Ketamine has been considered to be mainly a noncompetitive antagonist of the NMDA receptors . There are different subtypes of the NMDA receptors, a fact that might have therapeutic implications . There are other mechanisms, and ketamine has been characterized as ‘the nightmare of the pharmacologist’ owing to its complex mechanism of action . It has been reported to interact with opioid, monoamine, cholinergic, and adenosine receptor systems as well as having local anesthetic effects ,. It has even been speculated that the antiproinflammatory effects may be responsible for the antihyperalgesic effects of ketamine .
Wipfli et al.  concluded that the use of ultrasound guidance to perform spermatic cord block is feasible and has a high success rate. This approach may become a suitable alternative to neuraxial or general anesthesia, especially in the ambulatory surgical setting.
Birkhäuser et al.  observed that long-lasting perioperative analgesia was provided in patients undergoing microscopic vasectomy performed under ultrasound-guided spermatic cord block, in addition to early mobilization and hospital discharge.
Gamil and Fathy  studied the effect of ketamine as an adjuvant to bupivacaine in spermatic cord block for testicular sperm extraction surgery under general anesthesia. At the end of surgery, patients were allocated to receive either bupivacaine 0.5% plus ketamine 20 mg or bupivacaine 0.5% alone for spermatic cord block. They concluded that the addition of ketamine as an adjuvant to bupivacaine for spermatic cord block is a good option for postoperative pain control as it prolongs the duration of pain-free time and lowers the VAS score. The observed analgesic effect of ketamine in this study is not likely from central action, and it is most likely peripheral in origin.
Previous studies by Tverskoy et al. , Lashgarinia et al. , Tan et al. , and Ola et al.  assessed the effect of ketamine as adjuvant to peripheral nerve block concluded that addition of ketamine in peripheral nerve block results in decreasing the VAS postoperative pain and need for rescue analgesics. The results indicate that ketamine acting by a peripheral mechanism can profoundly enhance anesthetic and analgesic actions of a local anesthetic administered for infiltration anesthesia.
Noyan  concluded that ketamine enhances the activity of local anesthetic, so it shortens the onset and prolongs the duration of action. It was explained by the following reasons. Ketamine might increase the binding capacity of local anesthetic to albumin α-1 acid glycoprotein and change ionic balance.
| Conclusion|| |
The addition of (0.5 mg/kg) ketamine to lidocaine–bupivacaine mixture improves onset of the block and postoperative pain-free time (VAS) and reduces the consumption of postoperative analgesics with no complications in patients undergoing scrotal surgery under ultrasound-guided spermatic cord block.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]