The Efficacy and Safety of Local Anesthetic Infusion With Ropivacaine

The investigators hypothesize that continuous infusion of local anesthetic via a wound
catheter would improve postoperative pain control after UPJ correction and diminish the
adverse effects associated with current use of opioids, administered via epidural or systemic
route, for the management of postoperative pain. The expected benefits from wound catheter
infusion are reduction in postoperative opioids requirement thereby diminishing the
associated side effects of sedation, respiratory depression, nausea, vomiting, and ileus
which occur at an average rate of 50% in children and adolescents based on recent
meta-analysis. It may also facilitate early oral intake, ambulation and early discharge from
the hospital.

The current use of epidural indwelling catheters for analgesia is associated with 20-25%
technical failure rate from catheter misplacement, occlusion, disconnect or dislodgement,
premature discontinuation of analgesia due to opioid-related side effects, requires bladder
catheterization, and local anesthetic induced weakness in the lower extremities that usually
delays ambulation. The dose of local anesthetics infused via the epidural route is much
larger than proposed via wound catheters and carries greater risks of systemic toxicity
compared to infusion doses anticipated via wound catheter infusion. In addition, the use of
opioids such as morphine or hydromorphone via the epidural indwelling catheters produce
adverse effects similar to that of systemic opioids and require electronic and close nursing
monitoring.

Study Design

The study will include patients, male and female, between the ages of 3 months to 14 years of
all ethnic and race groups. Patients with a history of clinically significant cardiovascular,
pulmonary, hepatic, renal, neurologic, psychiatric or metabolic disease will be excluded.
After obtaining consent from a legal guardian, patients will be randomly assigned to the
placebo or treatment group. Both groups will receive rescue opioids for postoperative pain
management via either patient-controlled analgesia (PCA) or nurse-controlled analgesia (NCA)
administration for younger patients. The intraoperative anesthetic management will be
standardized in all patients.

The wound catheter (Soaker multi-orifice catheter approved by the FDA) will be placed at the
completion of the surgery in the subcutaneous space parallel and proximal to the surgical
incision by the surgeon. The Pain Treatment Service will manage postoperative pain with
standardized protocols including infusion of ropivacaine via the wound catheter and
administration of rescue opioids via PCA/NCA. Patients will be randomly assigned to receive
infusions of either ropivacaine or saline via the wound catheters.

Outcome Measures

The primary outcome measure is the total amount of opioids consumed by patients in the
treatment group compared to that consumed by the placebo groups, noting the potential
opioid-sparing effect in the patients treated with the continuous wound catheters with
ropivacaine versus saline in the placebo group. The secondary outcome measures include a
composite pain assessment scale (FLACC), that can be used as a self-report or observation
scale, incidence of opioid-related incidence of nausea, vomiting, sedation and respiratory
depression, time to first feed (as a measure of return of bowel function), transition to oral
analgesics, time to first ambulation and time to discharge from the hospital. Finally, any
adverse outcomes related to local anesthetic infusion, catheter related infection and
technical failure such as catheter occlusion and premature dislodgement will be recorded.

Patient Recruitment

Patients will be identified from the Urology Clinic scheduling office and recruited in the
Pre-operative Anesthesia Clinic.

Data Collection

Outcome measure data will be recorded by nurses and physicians who are unaware of the
randomization for 48hrs post-operatively. The following outcome measures will be recorded.
The total amount of opioids consumed by all patients over the first 48hrs after surgery, The
daily total amount and pattern of opioid use via a PCA or NCA pump will be recorded from the
electronic medical record. The pain assessment scores and adverse effects of opioids and
local anesthetic administration will be recorded by a standardized protocol. Other outcome
measures include the incidence of emesis, time to first feed or oral intake, pain intensity
assessment by self-report in older children and observation in younger children, and time to
discharge.

Statistical Analysis

Power analysis indicated that 48 patients randomized equally to each group (n=24 per group)
will provide 80% (alpha= 0.05, beta= 0.20) power to detect a 25% difference in total opioid
usage during the first 48 hours postoperatively. Fisher's exact test will be used to compare
binomial proportions of nausea/vomiting, sedation, respiratory depression, ileus, and
proportion of patients requiring postoperative opioids. In addition, groups will be compared
using Kaplan-Meier curves and will be constructed to model time to first oral intake with the
log-rank test to compare groups and 95% confidence intervals derived using Greenwood's
formula. A Uniform(0,1) random number generator will be used to determine treatment
allocation and to minimize any covariate imbalances between the ropivacaine and saline
groups. Two-tailed values of p<0.05 will be regarded as statistically significant.

Summary

The investigators anticipate that the simple measure of wound catheter infusion with
ropivacaine will demonstrate a significant safe and effective modality of analgesia in the
postoperative period. If our results are valid, improved pain modulation with such a simple,
low-tech modality of postoperative pain control (a) will require further investigation with a
larger patient population including broader categories of surgical procedures to determine
the limits of efficacy of such techniques in a particular surgical procedure, (b) may
demonstrate statistically and clinically significant decreases in pain and decrease opioid
demands, (c) may lessen time for recovery and side effects secondary to opioid use (d) offer
significant cost-benefit for in-patient care relative to currently used modalities of
epidural analgesia or systemic opioids for the management of postoperative pain in children
undergoing UPJ correction and (e) compared to presently used epidural and PCA opioid
analgesia, the wound catheter analgesia is expected to be less demanding on nurses and
physicians (i.e. Pain Treatment Service), staff time, attention and need for close
monitoring.

Inclusion Criteria:

- Diagnosis of UPJ stenosis requiring surgical repair

- Ages 3 months to 14 years old

- Guardians give consent and the child gives assent when appropriate

- Both genders

- All racial and ethnic groups

Exclusion Criteria:

- A history of chronic pain and/or use of chronic opioids and other analgesic(s)

- If parents/patients or attending urologist request epidural analgesia or refuse to
participate in the study

- Impairment of cognition/neurologic, hepatic, renal, cardiovascular, endocrine,
metabolic, and/or coagulation function

- A history of any diagnosis of psychiatric disorders, including bipolar disorders by
self-report or by guardian

- A recent history of illicit chemical abuse within one week prior to surgical date

- Participants known to be taking prescribed medications or over-the-counter medications
known to affect pain perception such as central nervous system stimulants, hypnotics,
sedatives, etc within 24 hours of planned surgical procedure