|Year : 2019 | Volume
| Issue : 12 | Page : 1737-1741
Comparison of the efficacy of eutectic mixture of local anesthetics (EMLA) and dorsal penile nerve block (DPNB) in neonatal circumcision
VI Modekwe1, JO Ugwu1, OH Ekwunife1, AN Osuigwe1, SO Obiechina1, IV Okpalike2, JC Orakwe3
1 Paediatric Surgery Unit, Department of Surgery, Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra State, Nigeria
2 Neurosurgery Unit, Department of Surgery, Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra State, Nigeria
3 Urology Unit, Department of Surgery, Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra State, Nigeria
|Date of Submission||20-May-2019|
|Date of Acceptance||14-Aug-2019|
|Date of Web Publication||3-Dec-2019|
Dr. V I Modekwe
Department of Surgery, Nnamdi Azikiwe University Teaching Hospital, PMB 5025, Nnewi, Anambra State
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Neonates feel pain. There is a concern among practitioners that pain of injecting analgesics to neonates prior to circumcision could as well be the same as the pain of the procedure. This has made many reluctant to offer effective analgesia for circumcision. If eutectic mixture of local anesthetics (EMLA) provides analgesia comparable to dorsal penile nerve block (DPNB), it will obviate needle prick and encourage analgesia use in neonatal circumcision. Aim: To determine how the analgesic efficacy of EMLA compares with that of DPNB in neonatal plastibell circumcision. Methods: A prospective study of 110 male neonates for plastibell circumcision randomized into two groups: A and B, of 55 each, received EMLA or DPNB as analgesia prior to circumcision, respectively. The pulse rates and SpO2 were recorded with pulse oximeter pre-procedural and at four stages of the procedure (adhesiolysis, dorsal slit, tying, and excision) for each neonate. Also the modification of neonatal infant pain scale (NIPS) was recorded during the procedure. Results: There were differential changes in SpO2 (lower absolute mean values) and pulse rate (higher absolute mean values) for neonates who received EMLA when compared with DPNB before the procedure. These differences were significant with SpO2 at adhesiolysis (91.0% and 95.0%), dorsal slitting (90.9% and 94.7%), and excision stages (93.4% and 95.3), respectively (P < 0.05). They were also significant with the pulse rates at adhesiolysis (167.9 and 158.6), dorsal slitting (174.3 and 161.7), and tying stages (182.2 and 169.0), respectively (P values = 0.013, 0.015, and 0.044, respectively). This shows DPNB is better than EMLA. However, the difference was not significant at the tying stage with SpO2 and at excision stage with PR (P > 0.05). Conclusion: EMLA produces analgesic effect. However, it does not provide effective analgesia for plastibell circumcision in neonates. DPNB provides a better analgesia than EMLA for neonatal plastibell circumcision.
Keywords: Circumcision, DPNB, EMLA, neonate, pain
|How to cite this article:|
Modekwe V I, Ugwu J O, Ekwunife O H, Osuigwe A N, Obiechina S O, Okpalike I V, Orakwe J C. Comparison of the efficacy of eutectic mixture of local anesthetics (EMLA) and dorsal penile nerve block (DPNB) in neonatal circumcision. Niger J Clin Pract 2019;22:1737-41
|How to cite this URL:|
Modekwe V I, Ugwu J O, Ekwunife O H, Osuigwe A N, Obiechina S O, Okpalike I V, Orakwe J C. Comparison of the efficacy of eutectic mixture of local anesthetics (EMLA) and dorsal penile nerve block (DPNB) in neonatal circumcision. Niger J Clin Pract [serial online] 2019 [cited 2020 Aug 7];22:1737-41. Available from: http://www.njcponline.com/text.asp?2019/22/12/1737/272204
| Introduction|| |
Circumcision is the world oldest and most controversial surgery. Neonatal age is the commonest age group in which circumcision is carried out., The role of analgesia in neonatal circumcision has added to the controversy surrounding circumcision. There is still reluctance in the use of effective intraoperative analgesia in neonatal circumcision., This is most predominant in Africa. This has stemmed from the argument that “neonates do not feel pain.” This has been debunked and clinical researchers have concluded that neonates do not only feel pain but feel it more intensely than adults. However, such notion still prevails among clinicians. There is also a fact to the cultural reason for circumcision in the olden times in which a young man's ability to bear the pain of circumcision is an evidence of readiness to enter the adulthood. This is no longer the reason for the performance of circumcision. Yet, this mindset has persisted in the current practice of circumcision in which “traditional'' mothers and clinicians continue to assume that the pain of neonatal circumcision need not be a consideration in the practice.
Commonly in our environment, there is the thinking that circumcision is fast and quick, and that the pain of injecting analgesics could as well be equivalent to the pain of circumcision. However, it is now clear that the consequences of a procedural pain, when not attenuated, is enormous and outlives the procedure itself.,, Subjecting neonates to an unmitigated pain during circumcision without analgesia has resulted in their exhibition of stronger pain responses to routine immunizations during the 6 months of life than infants who were not circumcised, suggesting that circumcision pain may exert long-term effects on infant behavior. Unmitigated pain could also lead to a disturbance of normal sleep--wake cycle of neonates and their responsiveness to the mother. Moreover, unmitigated circumcision pain causes a lot of deleterious systemic effects such as decrease in blood oxygen saturation, increased pulse and respiratory rates, increased output of adrenal corticoids, skin flushing, vomiting, and cyanosis.,,,,
Neonatal circumcision should not be conducted without adequate intraprocedural analgesia. There is a need, therefore, to explore a form of procedural analgesia that is both effective and safe, and also appeals to the providers of neonatal circumcision, as well as to those seeking the procedures for their neonates. It is thought that eutectic mixture of local anesthetics (EMLA) cream will provide a safe, adequate analgesia and obviates the need for needle prick in neonatal circumcision. The objective of this study therefore was to compare the analgesic efficacy of EMLA against a benchmark, dorsal penile nerve block (DPNB), which has been widely used and accepted for its analgesic efficacy,, and hence adopt a policy for the amelioration of pain in neonatal circumcision.
| Patients and Methods|| |
This is a hospital-based prospective randomized study conducted at the pediatric surgery unit of our center from November 2013 to October 2014. Ethical approval was sought and obtained from the ethical board (NAUTH/CS/Vol. 5/01). It involved sequential recruitment of neonates who were brought for routine circumcision at the clinic, and whose parents have given consent. All consecutive neonates were included in the study. Excluded from the study were male neonates with congenital penile anomalies like hypospadias, epispadias. Also excluded were neonates delivered preterm and have penile lesions like rashes and ulcers because of their higher risk for met-hemoglobinemia from EMLA.
Every week, recruited neonates were randomized into two groups, A and B by balloting, from a bag of 110 ballot papers, with equal amount of A and B. There is no restriction to feeding. The group A received each 1 g of EMLA® (ASTRA ZENECA UK; 2012; 015581) while group B received DPNB. The neonates in group A had the EMLA cream applied under an occlusive dressing which is left in place for 2 h before the circumcision procedure. The neonates in group B have 3 mg/kg of 1% plain lidocaine (Kwality Pharmaceuticals, India; 10/11; MH/DRUGS/6A2) injected in the vicinity of the dorsal penile nerve at 2 o'clock and 10 o'clock positions and a time of 3 min allowed for effect before onset of procedure. The operating room is made conducive for the neonates by having the air-conditioner switched off and the cleansing solutions warmed to reduce confounding effect on parameters of outcome measure.
Before and during the procedure, each of the neonate is placed on continuous pulse oximeter monitoring (CONTEC, CMS50EW, China; 140201013). The preprocedural SpO2 and pulse rate (PR) reading were noted after the administration of the respective analgesic and just before the procedure is commenced. It is ensured that the child is comfortable, calm, and not crying. These pulse oximeter readings were also taken just at the end of the stages of each procedure: adhesiolysis, dorsal slitting, tying, and excision. Also the CRY parameter of the neonatal infant pain scale (NIPS) was scored at the various stages of the procedure for both groups.
The age, weight, and preprocedural values of both groups were analyzed and compared for similarities. The readings of SpO2, PR, and CRY score were analyzed for mean, and compared for both groups at each stage for statistical significance, using Independent samples Mann--Whitney U test. t-test was used for age and weight comparison. Significance set at P value < 0.05. IBM® SPSS® statistics ver 21 was used for data input and analysis.
| Results|| |
A total of 110 male neonates were recruited and randomized into two groups of A and B of 55 each. Group A received EMLA while Group B received DPNB as their preprocedural analgesia. The mean age and weight of the groups are reflected in [Table 1] and showed no significant difference. The preoperative mean SpO2 for EMLA group was 95.3 (±2.6)% and 95.8 (±3.0)% for DPNB group were similar. Also the preoperative PR for the EMLA group was 144.0 (±19.9) and for the DPNB group was 140 (±22.5). These are shown in [Table 1].
During the procedure there were consistent drops in the SpO2 of the neonates in group A (EMLA group) compared with their preoperative values in all the four stages of the procedure [Table 2]. There were also drops in the SpO2 of the group B (DPNB) neonates in relation to their preprocedural values [Table 2]. However, when compared stage for stage, the mean procedural SpO2 were less at all the stages in the EMLA group compared with the DPNB group: adhesiolysis (91.0% and 95.0; P = 0.001), dorsal slit (90.9% and 94.7%; P = 0.001), tying (92.7% and 94.4%, P = 0.110), and excision (93.4% and 95.3%, P = 0.032), respectively. These were significant in adhesiolysis, dorsal slit, and excision stages. These are shown in [Table 3].
The mean pulse rates were increasing in all stages of the procedure compared with the mean preoperative values in the group A (EMLA) neonates [Table 2]. There were similar rise found in the Group B (DPNB) neonates [Table 2]. However, when the mean procedural pulse rates were compared, stage for stage, the increases were more with the EMLA neonates compared with the DPNB neonates (167.9 and 158.6; 174.3 and 161.7; 182.2 and 94.4; 171.8 and 167.1, respectively). These higher increments were statistically significant at the stages of adhesiolysis (P = 0.013), dorsal slit (P = 0.015), and tying (P = 0.044). These are shown in [Table 3].
The CRY parameter of the NIPS came out with more vigorous cry and mean scores at all the stages in the EMLA group compared with the DPNB group [Table 4] and [Table 5]. Again, at all the stages, the EMLA group had less number of subjects with “no cry” compared with the DPNB group, [Tables 5]. Also the EMLA group had the highest number of subjects with “vigorous cry” in all the stages compared with the DPNB group, [Tables 5].
| Discussion|| |
The safety and smoothness of neonatal circumcision lies in operating under adequate pain management. The neonates recruited in this study were similar for age and weight, P values of 0.078 and 0.305, respectively. The mean weight of the group A (EMLA) was 3.7 (±0.6) kg, 1 g of EMLA® cream was applied and is adequate for each neonates in line with manufacturers prescription. In their study, Mujeeb et al., used 1--2 g of EMLA, probably because their study was on infants up to 6 months. However, Quatani et al. used 1 g for their neonates in Plastibell® circumcision. The subjects were also similar for their mean preprocedural SpO2 and PR. These made it possible to compare the subsequent intraoperative recordings and to draw a robust conclusion. It was possible due to the consistent methodology adopted in ensuring that all the neonates were subjected to a conducive environment in terms of warmth of environment, warm cleansing solution, and friendly strapping. These findings were similar with other studies.,
This study was able to establish that EMLA® produces some analgesic effect for neonatal circumcision Plastibell®. There was no significant difference in the mean SpO2 of EMLA and DPNB neonates during the tying stage. There was also no significant difference in the mean pulse rate during the excision stage. These implied that EMLA and DPNB produced about similar effect at these stages. EMLA has several properties and advantages that will enable it to provide anesthetic and analgesic effect for neonatal circumcision., Topically applied EMLA penetrates through the epidermis up to 5 mm to act on sensory nerve endings in the dermis in order to provide effective anesthesia. EMLA blocks the A∂-fibers which transmit cold and pinprick sensation and the C-fibers which transmits warmth and dull pain. EMLA does this by inhibiting the peripheral nerve membrane ion fluxes necessary to generate an action potential. EMLA also has a high water content (which softens the stratum corneum, making it more permeable) together with high proportion of the lipophilic, unionized (basic) form of anesthetic, which makes EMLA membrane permeable. EMLA therefore has an effective tissue penetration. These become useful in the provision of analgesia during Plastibell® circumcision.
However, from this study, it is clear that DPNB is better than EMLA in at least three stages out of four in the procedure for either of the physiological parameters used. There was consistency at the adhesiolysis and dorsal slitting stages. These two involved interfering at the mucous layer of the prepuce, in addition with the cutaneous superficial layer. This was not surprising as EMLA is a dermal anesthetic agent., Specifically it is applied to prevent pain associated with intravenous catheter insertion, blood sampling, superficial surgical procedures, and topical anesthesia of leg ulcers for cleansing or debridement. Also, it can be used to numb the skin before tattooing as well as electrolysis and laser hair removal., It is not likely to penetrate enough through the whole thickness of the preputial layers, which are all innervated. This is unlike DPNB which block the dorsal nerve supply of the prepuce as it enters the penis. Overall, these outcomes suggest that EMLA does not penetrate to the depth required for circumcision and is not a prudent choice. In addition, there are no means of assuring uniform absorption of the EMLA cream given such factors as potential dilution by urine (as the occlusion dressing does not completely eliminate urine from coming in contact with the cream applied over the prepuce) or differences in skin thickness in different neonatal populations. Mujeebet al., got a different result from their study. During circumcision, they found significant increase in heart rate in DPNB group, especially in step three (tying stage) and step four (excision stage) (P< 0.04). Oxygen saturation dropped in both the groups (baseline saturation 98% up to 91% in step 4). While assessing NIPS scores in both the groups, they found statistically significant difference between NIPS at step two (dorsal slit stage) and step four in two groups (P< 0.04) to the advantage of EMLA group. They imply EMLA may be slightly better at providing analgesia for neonatal plastibell circumcision. This can be adduced to their methodology. Study was done on infants and not only on neonates. They used a varying dose of EMLA, 1--2 g. They did not state who got 1 g or 2 g. Again they applied EMLA on the glans and prepuce, which could mean EMLA was applied to the inner layer of prepuce, unlike in our study. Also their method of penile block was not DPNB. They injected 1 ml of lignocaine at the penile base without regard to the 2 o'clock/11 o'clock points of nerve entrance into the penis, and to patient's weight.
In their studies, Landeret al., Butler O'Hara et al., and Mascielloet al. found that EMLA provides some analgesia during neonatal circumcision in line with this study. Landeret al., however, noted that EMLA is not fully effective during all the stages of circumcision. Landeret al. made the following conclusions: “EMLA was not fully effective during the stage of surgery where the foreskin is separated from the glans and incised; it was less effective than the DPNB judging by the newborns' responses, which were more intense and prolonged''. Butler O'Haraet al. opined that EMLA may be better than no anesthesia but not to DPNB. Al Qahtani et al., in their study noted that the combination of sucrose and EMLA cream revealed a higher analgesic effect and minimal adverse response to pain than either EMLA cream or sucrose alone during neonatal circumcision. This means that EMLA alone as an analgesic for circumcision procedure leaves a gap in effective pain management.
| Conclusion|| |
We conclude that EMLA is not as effective as DPNB in providing analgesia for circumcision procedure in neonates. We therefore advocate the use of DPNB over EMLA. Going forward, studies are needed to see how combination with other adjuncts like oral sucrose and alteration in methods of application (e.g. applying within the prepuce) can improve the overall effectiveness of EMLA in neonatal circumcision.
Financial support and sponsorship
Conflicts of interest
We declare no conflicts of interest. We received no financial support from any source. This study was personally funded.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]