A Non-Narcotic Pathway for the Management of Postoperative Pain Following Pediatric Robotic Pyeloplasty

Abstract

Purpose:

The purpose of this study is twofold: first, to describe the non-narcotic pathway (NNP) for the management of postoperative pain after robotic pyeloplasty (RP); second, to compare perioperative outcomes for children undergoing RP whose postoperative pain was managed with and without the NNP.

Patients and Methods:

A retrospective review was performed on 96 consecutive patients from October 2011 to December 2015 who underwent RP by three primary surgeons at a single pediatric institution. Children managed with an NNP received alternating doses of scheduled intravenous acetaminophen and ketorolac every 3 hours throughout the postoperative course. Perioperative outcomes were compared after grouping patients according to the type of postoperative pain management pathway. Continuous variables were compared using the Mann–Whitney U test, and categorical variables were compared using the two-tailed chi-squared test.

Results:

A total of 49 (51.0%) patients were managed with the NNP, and 47 (49.0%) patients were managed without the NNP. A larger proportion of patients in the NNP did not receive postoperative narcotic medications (71.4% vs 25.5%; p < 0.001). Patients in the NNP were administered less narcotics (median 0.000 mg vs 0.041 mg morphine equivalents/kg/day; p < 0.001) and had a shorter length of stay (median 1.0 day vs 2.0 days; p < 0.001). There was no significant difference in the proportion of patients with postoperative complications (p = 0.958) or surgical success (p = 0.958).

Conclusions:

An NNP following pediatric RP is a viable and effective analgesic regimen that is associated with less narcotic use. It may also facilitate a shorter hospital stay. The majority of patients managed with this pathway had adequate pain control without being subject to the potential adverse effects of narcotic medications.

Introduction

Robotic surgery maintains the benefits of minimally invasive surgery while providing the surgeon with the ability to see in magnified three-dimensional vision, operate in limited anatomic spaces, and suture with precision. These attributes make the robotic modality well suited for technically challenging reconstructive surgeries, including pyeloplasty. Although open pyeloplasty (OP) has been the gold standard for operative repair of ureteropelvic junction obstruction in children, robotic pyeloplasty (RP) has gained increased acceptance and application.¹ Compared with OP, RP has been shown to be associated with similar success rates,^2
–4 improved cosmesis,⁵ decreased length of stay,^2
–4 and decreased postoperative pain.^2,3,6

Pain management is a critical component of postoperative care as it is directly related to clinical outcomes.⁷ Although postoperative pain in children has historically been under-recognized and undertreated, there have been increased efforts toward improving its assessment and management.^8,9 Narcotic medications, which are considered to be safe and effective for use in children,¹⁰ are widely utilized for postoperative pain management in the pediatric population.¹¹ However, narcotic analgesics frequently cause adverse drug reactions such as nausea, vomiting, pruritus, constipation, urinary retention, and sedation. Furthermore, narcotic medications may cause respiratory depression, which can potentially be fatal.¹⁰ Therefore, developing postoperative pain management strategies that can reduce or eliminate the adverse effects associated with narcotic analgesics, while still providing adequate pain control, are paramount.

In this context, we hypothesize that postoperative pain in children after RP may be effectively managed without narcotic medications in the majority of cases. Herein, the non-narcotic pathway (NNP) is described, and the perioperative outcomes are compared between children undergoing RP managed with and without the NNP.

Patients and Methods

Study cohort

An Institutional Review Board-approved retrospective review was performed on 96 consecutive patients who underwent RP by three primary surgeons between October 2011 and December 2015 at a single pediatric institution. Study inclusion criteria included all children ≥12 months of age with symptomatic ureteropelvic junction obstruction and/or Society for Fetal Urology grade 3–4 hydronephrosis¹² with an abnormal diuretic renal scan. RP was performed as previously described.^2,13

Patients were divided into two groups based on clinical practice patterns. One of three primary surgeons employed the NNP. Children in this cohort received alternating doses of 15mg/kg of intravenous (IV) acetaminophen and 0.5 mg/kg of IV ketorolac every 3 hours throughout the postoperative hospital course. If breakthrough pain medications were required, oral and/or IV narcotic medications were administered after clinical evaluation. Patients who were unable to receive both IV acetaminophen and ketorolac, such as those with renal insufficiencies and underlying bleeding disorders, were managed without the NNP. Two of three primary surgeons did not employ the NNP. Patients managed without the NNP received a combination of oral and/or IV narcotic medications as needed for pain, with or without IV acetaminophen and/or ketorolac based on the primary surgeon and clinical course. These patients did not routinely receive scheduled IV acetaminophen and ketorolac. Some patients in this cohort also received epidural analgesia. In all cases, the patients' parents were agreeable to the pain management pathway utilized by their child's surgeon. Staff nurses who were trained in the utilization of pain scales performed postoperative pain assessments on the patients every 2–4 hours. The Face, Legs, Activity, Cry, Consolability scale was used in children 7 years of age or younger.¹⁴ The revised Faces scale was used in children greater than 7 years of age.¹⁵

Perioperative outcomes were compared after grouping patients according to the type of postoperative pain management pathway. The primary outcome was whether or not narcotic medications were administered. Secondary outcomes were IV morphine equivalents administered (mg/kg/day), length of stay, postoperative complications, and surgical success. Postoperative complication was defined as any complication with Clavien grade ≥2.¹⁶ Surgical success was defined as resolution of preoperative symptoms or improvement of hydronephrosis on ultrasound.

Statistical analysis

Continuous variables were compared using the Mann–Whitney U test, and categorical variables were compared using the two-tailed chi-squared test. In all cases, p < 0.05 was considered to be statistically significant. Statistical analyses were conducted with Minitab 16 (Minitab, Inc., State College, PA).

Results

A total of 49 (51.0%) patients were managed with the NNP, and 47 (49.0%) patients were managed without the NNP. Patient characteristics according to the type of postoperative pain management pathway utilized are shown in Table 1. With regard to patient characteristics, there was no difference in median age (p = 0.119) and weight (p = 0.097) between the two groups. In addition, there was no difference in the proportion of male/female patients (p = 0.429), of left/right-sided disease (0.880), and of patients with crossing vessel/intrinsic obstruction (p = 0.406).

Table 1.

Patient Characteristics

	Non-narcotic pathway (N = 49)	Narcotic pathway (N = 47)	p
Median age [range] (m)	63 [13–255]	91 [12–279]	0.119
Median weight [range] (kg)	19.9 [8.6–92.3]	27.0 [10.0–96.0]	0.097
Gender, n (%)
Male	32 (65.3)	27 (57.4)	0.429
Female	17 (34.7)	20 (42.6)
Laterality, n (%)
Left	32 (65.3)	30 (63.8)	0.880
Right	17 (34.7)	17 (36.2)
Abnormality, n (%)
Crossing vessel	25 (51.0)	20 (42.6)	0.406
Intrinsic	24 (49.0)	27 (57.4)

Operative and postoperative outcomes according to the type of postoperative pain management pathway utilized are shown in Table 2. There was no difference in median operative time (p = 0.133) between the two groups. None of the patients managed with the NNP received epidural analgesia, while 11/47 (23.4%) patients managed without the NNP received epidural analgesia (p < 0.001). A larger proportion of patients in the NNP did not need narcotic medications compared with those managed without the NNP (71.4% vs 25.5%; p < 0.001). Patients managed with the NNP received less postoperative narcotic medications, measured in median morphine equivalents, than those managed without the NNP (0.000 mg vs 0.041 mg morphine equivalents/kg/day; p < 0.001).

Table 2.

Operative and Postoperative Outcomes

	Non-narcotic pathway (N = 49)	Narcotic pathway (N = 47)	p
Median operative time [range] (minutes)	188 [118–300]	193 [115–447]	0.133
Epidurals, n (%)	0 (0.0)	11 (23.4)	<0.001
No narcotics received, n (%)	35 (71.4)	12 (25.5)	<0.001
Median morphine equivalents received [range] (mg/kg/day)	0.000 [0.000–0.109]	0.041 [0.000–0.336]	<0.001
Median length of stay [range] (days)	1 [1–3]	2 [1–7]	<0.001
Median follow-up [range] (m)	6 [1–17]	5 [1–28]	0.472
Postoperative complications, n (%)	3 (6.1)	3 (6.4)	0.958
Success rate, n (%)	46 (93.9)	44 (93.6)	0.958

Patients managed with the NNP had a shorter median length of stay compared with patients managed without the NNP (1.0 day vs 2.0 days; p < 0.001). There was no significant difference in median follow-up (p = 0.472) between the two groups. There was no significant difference in the proportion of patients with postoperative complications (p = 0.958) or surgical success (p = 0.958).

Discussion

RP, compared with OP, has been shown to be associated with decreased postoperative pain.^2,3 In a report by Lee and colleagues, pediatric patients who underwent RP did not receive epidural analgesics, whereas 55% of patients undergoing OP did. Furthermore, patients who underwent RP had a significantly lower postoperative narcotic requirement.³ Similar results have also been shown in the infant population. In a report by Bansal and colleagues, infant patients who underwent RP did not receive epidural analgesics, whereas 65% of patients undergoing OP did. In addition, infants who underwent RP had a lower postoperative narcotic requirement than those who underwent OP.² Although neither study detailed their approach to postoperative pain management, both studies reported a low postoperative narcotic requirement and had patients that did not require any postoperative narcotics.^2,3

The results of this study show that postoperative pain after RP may be managed without narcotics in the majority of cases. Our NNP for children after RP involves the administration of alternating doses of scheduled IV acetaminophen and ketorolac every 3 hours throughout the patient's postoperative course. Using this regimen, 35/49 (71.4%) patients did not receive narcotics after RP, which was significantly higher than the 12/47 (25.5%) of patients who did not require narcotics in the group managed without the NNP (p < 0.001). Furthermore, patients managed with the NNP received less narcotic medications postoperatively (median 0.000 mg vs 0.041 mg morphine equivalents/kg/day; p < 0.001). Patients in the NNP had a shorter length of stay than those who received pain control without the NNP (median 1.0 day vs 2.0 days, p < 0.001). Although not directly assessed, we believe that this was partially due to a decrease in the adverse effects of narcotic medications such as slower bowel motility.

There are two aspects of our NNP that make it effective in eliminating postoperative narcotic utilization in the majority of children undergoing RP. First, both IV acetaminophen and ketorolac were utilized for postoperative pain management. The American Society of Anesthesiologists recommends using at least two analgesic medications that act by different mechanisms for postoperative pain management. Using a combination of medications not only maximizes analgesic efficacy but also minimizes the adverse effects of any one medication used alone.⁸ Although the exact mechanism of action is not entirely understood, acetaminophen primarily works by inhibiting cyclooxygenase (COX)-1 and COX-2 with a higher affinity for COX-2. Inhibition of these enzymes prevents the production of prostaglandin-2, a chemical mediator active in nociception and inflammation.¹⁷ Ketorolac works by inhibiting COX-1 and COX-2, with a higher affinity for COX-1. The inhibition of COX-1 also leads to the decrease in synthesis of thromboxane, a chemical mediator that promotes platelet aggregation, which may cause increased bleeding.¹⁸ Although the potential for increased bleeding may deter surgeons from routinely using IV ketorolac for the management of postoperative pain after RP, we did not encounter any bleeding complications in any of the patients who received IV ketorolac in our study.

Second, patients managed with our NNP received analgesics on a time-contingent basis, rather than a pro re nata (PRN) basis. Administering analgesics on a time-contingent basis allows for the management of pain before acute pain begins, while medications are at the end of effectiveness. Alternatively, administering analgesics on a PRN basis may delay the treatment of pain due to the time required for pain assessment and for the analgesic to take effect.¹⁹ As a result of this delay, the pain may ultimately require a larger analgesic dose for control.²⁰ This issue may be magnified in younger children and infants who have a harder time communicating their need for pain medication. In a prospective, randomized clinical trial evaluating pain control in children after outpatient tonsillectomy, Sutters and colleagues found that children receiving acetaminophen and hydrocodone around the clock had lower pain intensity scores compared with children who received acetaminophen and hydrocodone PRN.²¹ Currently, the American Academy of Pediatrics and the American Pain Society²² and the American Society of Anesthesiologists⁸ recommend using a time-contingent analgesic dosing for the management of postoperative pain in children.

Also noteworthy is that 12/47 (25.5%) patients managed without our NNP did not receive narcotics. This finding is consistent with prior reports that have shown that some patients do not require narcotic medications postoperatively after RP, even when narcotic medications are readily available.^2,3 This finding may be attributed to the decreased degree of intrinsic postoperative pain after laparoscopic approaches for pyeloplasty.

The results of our study must be taken in the context of its limitations. Our study is inherently limited by its retrospective design. In addition, we were unable to compare the degree of pain control between the two groups. Although patients in the NNP received narcotic medications less frequently than those managed without the NNP, it is unclear whether patients in the NNP had better pain control compared with those managed without the NNP. Furthermore, the one primary surgeon who employed the NNP had more experience with robotic surgery than the two other primary surgeons, which may have confounded our results.

Conclusions

NNP following pediatric RP is a viable and effective analgesic regimen that is associated with less narcotic use. It may also facilitate a shorter hospital stay. The majority of patients managed with this pathway had adequate pain control without being subject to the potential adverse effects of narcotic medications.

Footnotes

Acknowledgment

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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