 |
|
Ropivacaine With or Without Clonidine Improves Pediatric Tonsillectomy Pain
Carla Giannoni, MD;
Sno White, MD;
F. Kayser Enneking, MD;
Timothy Morey, MD
Arch Otolaryngol Head Neck Surg. 2001;127:1265-1270.
ABSTRACT
| |
Objective To determine if preemptive analgesia with ropivacaine hydrochloride
with or without clonidine hydrochloride decreases pain and hastens recovery
after tonsillectomy.
Design Prospective, randomized, triple-blinded trial.
Setting University referral center; pediatric ambulatory practice.
Participants Sixty-four children, aged 3 to 15 years, undergoing tonsillectomy.
Interventions Patients received injections in the tonsillar fossae of isotonic sodium
chloride, ropivacaine, or ropivacaine plus clonidine prior to tonsil excision.
Main Outcome Measures Visual analogue (pain) scale scores at rest and when drinking, opioid
use, recovery time to normal activity, and incidence of symptoms such as otalgia.
Results Pain was reduced on postoperative day 0 in the ropivacaine-treated and
ropivacaine plus clonidine–treated groups as compared with the isotonic
sodium chloride–treated group (P<.05). Pain
was also decreased in the ropivacaine plus clonidine–treated group on
postoperative days 3 and 5 (P<.05). Intravenous
narcotic use was decreased on day 0 in the ropivacaine-treated and ropivacaine
plus clonidine–treated groups (P<.05). Cumulative
codeine use was similar at day 3 for all patients, but was decreased at day
5 in the ropivacaine plus clonidine–treated group (P<.05). The incidence of otalgia decreased from 89% (16/18) in the
isotonic sodium chloride–treated group to 63% (12/19) in the ropivacaine-treated
and 61%(11/18) in the ropivacaine plus clonidine–treated groups (P<.01). Recovery to normal activity was shortened from
8.1 ± 1.6 days to 5.8 ± 2.9 days (mean ± SD) in the isotonic
sodium chloride–treated and ropivacaine plus clonidine–treated
groups, respectively (P = .03).
Conclusion Preincisional injection of ropivacaine with clonidine prior to tonsillectomy
has a preemptive analgesic effect that outlasts the local anesthetic and decreases
pain, opioid use, and the time to return to normal activity.
INTRODUCTION
MORE THAN 280 000 children undergo tonsillectomy annually in the
United States.1 Although children receive analgesics
for pain control, operative pain remains a significant problem that is often
undertreated in the pediatric population for several reasons. Children often
refuse analgesics because the medication is not palatable or causes adverse
effects such as nausea, vomiting, or somnolence. In addition, parents may
not always recognize that a child is suffering because the child does not
complain, but rather withdraws or becomes depressed.
Prevention of pain perception may be a key factor in the management
of postoperative pain. Several studies have shown that the analgesic effects
of local anesthetics applied prior to injury far outlast the effects of local
anesthetics instilled following injury.2-5
For example, Jebeles et al6-7
reported a 10-day amelioration of pain scores in children who received bupivacaine
local anesthetic infiltration prior to tonsillectomy compared with placebo
injection. Subsequent studies, however, have failed to reproduce these results.8-9 Furthermore, no studies have assessed
the effects of ropivacaine or the value of clonidine supplementation to the
injectate. Ropivacaine is a new, synthetic, long-acting, amide-type local
anesthetic with intrinsic vasoconstrictive properties. Compared with racemic
bupivacaine hydrochloride, ropivacaine has equivalent anesthetic properties
but has less potential to cause serious cardiotoxic reactions (eg, arrhythmogenicity,
cardiac depression). Its duration of action is 6 to 8 hours in peripheral
block. The addition of vasoconstrictors and certain other agents to local
anesthetic injectate improves the onset, intensity, and duration of anesthesia
and preemptive analgesia. Clonidine is a centrally acting sympathologic agent
that has intrinsic analgesic properties and has been shown to prolong the
effect of regional anesthesia with amide anesthetics. Because of its analgesic
and sedating activity, clonidine has been used previously as an oral premedication
in patients undergoing tonsillectomy,10 but
its use, as an injectable supplement to a local anesthetic has not been evaluated.
Therefore, we undertook this study to examine the effects of preemptive ropivacaine
with or without clonidine on pain and recovery in children undergoing tonsillectomy.
SUBJECTS, MATERIALS, AND METHODS
To determine the possible benefit of preemptive analgesia for children
undergoing tonsillectomy, a prospective, randomized, triple-blinded study
of 64 children, aged 3 to 15 years, was performed. The study received University
of Florida institutional review board approval. One hundred consecutive patients
of a single attending surgeon (C.G.) scheduled for tonsillectomy were offered
enrollment in the study. Parents gave written consent to enroll their children
in the study. Children were randomized to 1 of 3 study arms described subsequently
by use of a random number generator (Excel; Microsoft Corp, Redmond, Wash).
The study drug was supplied as syringes of a liquid, identical in color and
volume but designated by a letter to 1 of the study groups. All physicians,
nurses, patients, parents, and others were blinded to the assignment of the
children to the study arms until the conclusion of the study. Four patients
were enrolled but did not complete the evaluation period and were excluded
from statistical analysis.
Children received a premedication combination of oral ibuprofen (15
mg/kg) and midazolam hydrochloride (0.5 mg/kg; maximum dose, 20 mg) followed
by a standard general inhalational anesthetic. Children also received 1 µg/kg
of fentanyl citrate and 0.25 mg/kg of metaclopropamide intravenously. All
children had peritonsillar injection of the assigned study drug after induction
of anesthesia and prior to excision of the tonsils. Those in the isotonic
sodium chloride–treated group (hereafter referred to as the saline-treated
group) received tonsillar injections of isotonic sodium chloride (0.16 mL/kg),
those in the ropivacaine hydrochloride–treated group received tonsillar
injections of a combination of 1% ropivacaine hydrochloride (0.15 mL/kg) and
isotonic sodium chloride (0.01 mL/kg), and those in the ropivacaine plus clonidine
hydrochloride–treated group received tonsillar injections of a combination
of ropivacaine hydrochloride (0.15 mL/kg) and clonidine (1 µg/kg [0.01
mL/kg]). The maximal total injectate volume was 4 mL per tonsil. A minimum
duration of 5 minutes was allowed for the onset of action of the study drug.
The procedures were performed by otolaryngology residents who had a similar
level of experience under the direct supervision of one of us (C.G.). The
same electrocautery dissection technique for tonsillectomy was used in all
cases.
Postoperative care, including control of pain and nausea, was based
on a study protocol and was identical for all patients. All children received
acetaminophen with codeine (24 mg of acetaminophen; 2.4 mg of codeine per
milliliter) (every 4 hours as needed) for postoperative pain control. Pain
was measured at rest and when drinking and scored on a visual analogue scale
(VAS). On postoperative days 0, 1, 2, 3, 5, and 10, VAS pain scores and activity
level were recorded for all participants. Cumulative analgesic medication
use was recorded on days 3, 5 and 10. Weight and urine specific gravity on
days 0 and 5 were recorded as an indirect measure of hydration status. All
adverse effects including bleeding and hospital admissions were recorded.
Tests of statistical significance for interval data were performed using
a paired t test, a 1-way analysis of variance (ANOVA),
or a 2-way repeated measured ANOVA followed by Bonferroni correction for multiple
comparisons (SSPS Version 10.0; SPSS Inc, Chicago, Ill) when appropriate.
Nominal data were analyzed using the  2 test or Fisher exact
test when appropriate. All data are expressed as mean ± SD. A value
of P<.05 was considered statistically significant.
The study was powered around the VAS pain score. Calculations were performed
using a change in (VAS) means of 2.0 with an SD of 2.0. The study power was
estimated to be 0.89% with a sample size of 20 subjects per group.
RESULTS
The study patients were comparable between groups for age, sex, and
operation performed (Table 1).
Fifty-seven patients had adenotonsillectomy and 7 had tonsillectomy only.
Eight patients concurrently had placement of tympanostomy tubes, 1 had removal
of a retained tympanostomy tube, and 1 had a frenulectomy.
|
|
|
|
Table 1. Patient Demographics for Children Randomized to the 3 Treatment
Groups
|
|
|
Pain medication use in the immediate postoperative period was significantly
different between the groups (Table 2).
Use of additional intravenous fentanyl was higher in the saline-treated group
than the ropivacaine-treated or ropivacaine plus clonidine–treated groups
(P = .049). Remarkably, all of the patients in the
saline-treated group required additional intravenous or oral narcotic pain
medications during the 3-hour recovery room stay, whereas 5 patients (24%)
in the ropivacaine-treated group and 8 (36%) of the patients in the ropivacaine
plus clonidine–treated group required no additional analgesics.
|
|
|
|
Table 2. Pain Medication Use
|
|
|
Children in the saline-treated group had significantly more pain both
at rest and with swallowing in the recovery room than did children in either
of the ropivacaine-treated groups (Figure
1). No difference between groups was seen at 24 and 48 hours postoperatively.
The VAS pain scores taken at rest and with swallowing were greater for the
saline-treated group compared with the ropivacaine plus clonidine–treated
group on postoperative days 3 and 5 (P<.05). The
VAS scores taken at rest were similar to those taken with swallowing although
the scores with swallowing tended to be lower. All children had normal or
near-normal VAS scores (VAS = 0) by postoperative day 10.
Cumulative codeine use was similar between the groups for the first
3 postoperative days but was significantly lower for the ropivacaine plus
clonidine–treated group on postoperative day 5 (Table 2). Data for cumulative codeine use at day 10 could not be
analyzed owing to the high percentage (42%, 27 subjects) of subjects for whom
that data could not be collected. The first 5 days of recovery are clearly
the most significant for analysis: 26 (62%) of 37 parents who did report total
codeine use at day 10 reported that 2 or fewer additional doses were used
between days 5 and 10. Analyses of the doses of other analgesic medications,
such as ibuprofen and plain acetaminophen, showed no differences between the
3 groups.
Subjective symptoms of headache, otalgia, and nausea were evaluated
(Table 3). There was a significant
decrease in the incidence of referred ear pain (otalgia) from 89% (16/18)
in the control group to 63% (12/19) and 61% (11/18) in the 2 ropivacaine-treated
groups. A trend of less nausea and vomiting was seen in those 2 groups.
|
|
|
|
Table 3. Subjective Symptoms*
|
|
|
Complications were similar among the 3 groups including estimated surgical
blood loss, weight loss, hospital admission, and posttonsillectomy hemorrhage
(Table 4). Bleeding was defined
as the appearance of bright red blood by mouth or nose or the occurrence of
hematemesis regardless of whether the bleeding required a physician's evaluation.
No patient in any group reported posttonsillectomy bleeding and no subject
required a second surgical procedure. All surgical procedures were performed
on an outpatient basis; no unexpected hospital admissions occurred in the
first 24 hours after surgery. The 2 emergency center visits and 2 hospital
admissions were due to pain, poor oral intake, and/or dehydration. Overall
hydration status was assessed by weight loss between day 0 and day 5 and was
found to be similar between all children. Children had both weight measurements
taken on the same scale at the outpatient surgical center. The weight loss
experienced by patients varied widely. The average weight loss was 1.5% of
preoperative weight, whereas the maximal weight loss was 10% of preoperative
weight. Specific gravity of morning urine was collected on day 5 but showed
no differences between groups even when compared with immediate postoperative
urine samples.
|
|
|
|
Table 4. Complications of Tonsillectomy*
|
|
|
Parental assessment of activity on a 4-point scale was recorded on days
0, 1, 2, 3, and 5. No statistical difference was seen between the 3 groups.
Injection of anesthetic with or without clonidine significantly accelerated
the time to complete recovery as defined by the time to return to a completely
normal level of activity. Injection of ropivacaine alone tended to improve
recovery to 6.5 ± 2.0 days (P = .17 compared
with placebo) but did not affect recovery time compared with the ropivacaine
plus clonidine–treated group. The duration of recovery shortened from
8.1 ± 1.6 days to 5.8 ± 2.9 days in the placebo and ropivacaine
plus clonidine–treated groups, respectively (P
= .03).
COMMENT
Recent advances in the study of pain delineate clear differences between
inflammatory pain, the type produced by surgical trauma, and physiologic or
functional pain. Physiologic pain is a response to a specific stimulus, a
warning to the organism to withdraw from danger. When the organism cannot
retreat, as when immobilized by general anesthesia, a vicious cycle commences.11 Continued injury of tissue causes long-lasting changes
in sensitivity. Two mechanisms help produce this state. First, chemical mediators
released by injury cause peripheral hypersensitivity of primary sensory neurons.12 Second, hyperexcitation of the spinal cord causes
low threshold A-B mechanoreceptors to begin transmitting painful sensations
creating central hypersensitivity.11 Hypersensitivity,
hyperalgesia, and secondary hyperalgesia occur. Hypersensitivity lowers the
intensity of stimuli required to trigger a reaction. Hyperalgesia magnifies
the response generated by the sensed stimulus. Secondary hyperalgesia spreads
hypersensitivity to noninvolved tissue.
The idea of providing preemptive analgesia to block the development
of hypersensitivity and hyperalgesia and, thus, decrease postsurgical pain
is not new. As early as 1953, otolaryngologists were using local injection
of anesthetics to relieve posttonsillectomy pain.13
Jebeles et al,6 in 1991, renewed interest in
preemptive analgesia for tonsillectomy when they demonstrated that the preemptive
effect of preincisional bupivacaine plus epinephrine on pain lasted a full
10 days after surgery.6 Goldsher et al14 and Johansen et al15also
showed a decrease in pain after tonsillectomy using preincisional bupivacaine
for 2 and 10 days, respectively. Not all investigators, however, have been
able to reproduce these promising results.8, 16-18
An overview of past studies suggested that higher patient numbers per study
group, higher doses of local anesthetic, and addition of epinephrine to local
anesthetics were potentially associated with positive preemptive effects.
In this study preemptive injection of a combination of ropivacaine plus
clonidine significantly improved pain and recovery after tonsillectomy in
several measured areas. One measure of pediatric pain assessment is the self-reported
VAS. The main limitation of the self-report assessment is the wide degree
of interpatient variability. The scale has been validated in children as young
as 3 years and provides reasonable trending for a given patient. Pain scores,
both at rest and with drinking, on days 3 and 5 were statistically significantly
lower in children receiving the combination injection compared with those
receiving injections of either saline or ropivacaine alone. In adult patients
VAS scores are generally correlated as follows: 3 or less, minimal pain; 4
to 6, moderate pain; and 7 to 10, severe pain. Thus, these VAS results are
not only statistically but also clinically significant because they show a
decrease from moderate pain to minimal pain. Further evidence of the subjects'
improved clinical recovery is seen in the analysis of codeine use. The groups
used similar amounts of pain medication through day 3, but by day 5 the study's
ropivacaine plus clonidine–treated group had used significantly less
pain medication. A final behavioral measure of pain is the parental report
of time to final recovery. The children in the saline-treated group had the
longest recovery, 8.1 days on average, compared with the ropivacaine-treated
group, 6.1 days, and the ropivacaine plus clonidine–treated group, 5.8
days (P<.05).
To our knowledge, associated quality-of-life issues such as referred
pain (otalgia) have not been evaluated in other studies. Otalgia was significantly
decreased for both ropivacaine-treated groups. This observation supports the
hypothesis that preemptive analgesia may act by decreasing central sensitization.
The failure of the VAS pain scores and other variables to achieve significant
differences in the ropivacaine-treated group compared with the control group
is consistent with the finding of previous studies with few patients in the
study groups. Because of the many pathways involved in surgical pain, one
can hypothesize that local anesthetic alone cannot consistently lessen the
incidence or severity of postoperative pain.
In our patients there were relatively high VAS scores in all groups
initially but an abrupt decrease in the VAS in the ropivacaine plus clonidine–treated
group compared with the control group at postoperative days 3 and 5. This
was consistent within each group of patients as reflected by the low SDs within
each group and was also correlated with the behavioral scores between each
group reflected in the more rapid return to activity in the ropivacaine-treated
and ropivacaine plus clonidine–treated groups. As discussed earlier,
current theories for the mechanisms of surgical pain, as well as some chronic
pain conditions, explain the seemingly unusual finding of lessened pain at
postoperative days 3 and 5 but not postoperative days 1 and 2 in our study
group. Preemptive analgesia has been investigated by numerous studies and
is proposed to work by preventing "windup" or central sensitization. Preemptive
analgesia using local anesthetics has its effect by decreasing the peripheral
nociceptive stimulus that, in turn, decreases the development of peripheral
hyperalgesia and peripheral hypersensitivity. The lessening of peripheral
sensitization decreases the central spinal cord stimulation thereby preventing
central hyperexcitation and central sensitization. Overall, this has the effect
of maintaining a high nociceptive threshold and low state of central sensitization
compared with the state where no peripheral analgesia is present before the
traumatic stimulus is initiated. The study results suggest that the initial
inflammatory pain due to tissue trauma is not lessened by preemptive analgesia.
As the inflammatory pain subsides, the effect of preemptive analgesia is seen
in the lessening of the physiologic component of surgical pain.
These data suggest that combining clonidine with local anesthetics has
an additive effect on pain control. The VAS pain scores and recovery rate
in the ropivacaine-treated group were in between the values of the control
group and those of the ropivacaine plus clonidine–treated group. The
addition of clonidine in the ropivacaine plus clonidine–treated group
proved to be an important factor that significantly enhanced analgesia and
recovery in these children. Clonidine seems to be responsible for the decrease
in the need for supplemental analgesia in the later postoperative period (days
3-5). In our study, the addition of clonidine to ropivacaine significantly
improved pain and recovery after tonsillectomy.
There are some limitations of this study. Although a computer-generated
randomization was used to assign children to the study arms, a trend to assign
more patients undergoing tonsillectomy only to the ropivacaine plus clonidine–treated
group occurred. This might influence early pain but is probably not a notable
factor in late pain and recovery where our most substantial findings occurred.
Arguably, the number of subjects in this study is not adequate to fully assess
the effect of ropivacaine or ropivacaine plus clonidine on postoperative complications
such as posttonsillectomy bleeding or hospital admission. Finally, the evaluation
of pain in children is difficult. Although validated for children as young
as 3 years, the VAS pain scale can be confusing for children to use. Pain
medication use is difficult to quantify since it requires precise dosing of
a liquid preparation; accounting for loss due to spillage, vomiting, and spitting;
and precise record keeping. Furthermore, the use of pain medication varies
widely among children after identical surgical procedures. Despite these intrinsic
limitations, because multiple measures of pain and recovery were used, the
results reflect a clear effect of ropivacaine plus clonidine on tonsillectomy
pain.
CONCLUSIONS
This study shows that a significant reduction in late posttonsillectomy
pain and medication use can be achieved using a combination of ropivacaine
plus clonidine. The injection of local anesthetic had a clear effect on immediate
postoperative pain control in both ropivacaine-treated groups that disappeared
by the next morning. After 2 days of significant discomfort, the ropivacaine
plus clonidine–treated group began to do significantly better than their
counterparts; this effect continued to complete recovery. Thus, we believe
the value of preemptive analgesia is in the reduction of pain in the recovery
room and in the latter half of the recovery period. Referred pain likely results
from stimulation of a different pain pathway than local surgical pain. This
may explain the remarkable decrease in otalgia in both ropivacaine-treated
groups in the late postoperative period. The combined data of VAS pain scores,
medication use, and return to normal activity demonstrate that there is a
preemptive effect of the use of ropivacaine plus clonidine on recovery from
tonsillectomy.
AUTHOR INFORMATION
Accepted for publication May 17, 2001.
Presented at the 16th Annual Meeting of the American Society of Pediatric
Otolaryngology, Scottsdale, Ariz, May 9-12, 2001.
We gratefully acknowledge the administrative efforts of Susan Degennaro,
RN, who was essential in the organized implementation of this study.
Corresponding author and reprints: Carla Giannoni, MD, Pediatric
Otolaryngology, 1102 Bates, Suite 340, Houston, TX 77030 (e-mail: cmgianno{at}texaschildrenshospital.org).
From the Department of Otorhinolaryngology, Baylor College of Medicine,
Houston, Tex (Dr Giannoni); and the Department of Anesthesia, University of
Florida, Gainesville (Drs White, Enneking, and Morey). Dr Giannoni is now
with the Texas Children's Hospital, Houston. Drs White and Enneking are members
of the Speakers' Bureau for AstraZeneca US, Westboro, Mass.
REFERENCES
| |
1. Owings MF, Kozak LJ. Ambulatory and inpatient procedures in the United States, 1996. Vital Health Stat 13. 1998;139:1-119.
2. Tverskoy M, Cozacovc C, Ayache M, Bradley EL Jr, Kissin I. Postoperative pain after inguinal herniorrhaphy with different types
of anesthesia. Anesth Analg. 1990;70:29-35.
FREE FULL TEXT
3. Ejlersen E, Andersen HB, Eliasen K, Morgensen T. A comparison between preincisional and postincisional lidocaine and
postoperative pain. Anesth Analg. 1992;74:495-498.
FREE FULL TEXT
4. Dahl JB, Brennum J, Arendt-Nielsen L, Jensen TS, Kehlet H. The effect of pre-versus postinjury infiltration with lidocaine on
thermal and mechanical hyperalgesia after heat injury to the skin. Pain. 1993;53:43-51.
FULL TEXT
|
ISI
| PUBMED
5. Holthusen H, Eichwede F, Stevens M, Willnow U, Lipfert P. Pre-emptive analgesia: comparison of preoperative with postoperative
caudal block on postoperative pain in children. Br J Anaesth. 1994;73:440-442.
FREE FULL TEXT
6. Jebeles JA, Reilly JS, Gutierrez JF, Bradley EL Jr, Kissin I. Effect of pre-incisional infiltration of tonsils with bupivicaine on
pain following tonsillectomy under general anesthesia. Pain. 1991;47:305-308.
FULL TEXT
|
ISI
| PUBMED
7. Jebeles JA, Reilly JS, Gutierrez JF, Bradley EL Jr, Kissin I. Tonsillectomy and adenoidectomy pain reduction by local bupivacaine
infiltration in children. Int J Pediatr Otorhinolaryngol. 1993;25:149-54.
FULL TEXT
|
ISI
| PUBMED
8. Schoem SR, Watkins GL, Kuhn JJ, Thompson DH. Control of early postoperative pain with bupivicaine in pediatric tonsillectomy. Ear Nose Throat J. 1993;72:560-563.
PUBMED
9. Stuart JC, MacGregor FB, Cairns CS, Chandrachud HR. Peritonsillar infiltration with bupivicaine for paediatric tonsillectomy. Anaesth Intensive Care. 1994;22:679-682.
ISI
| PUBMED
10. Reimer EJ, Dunn GS, Montgomery CJ, Sanderson PM, Scheepers LD, Merrick PM. The effectiveness of clonidine as an analgesic in paediatric adenotonsillectomy. Can J Anaesth. 1998;45:1162-1167
ISI
| PUBMED
11. Woolf C, Chong MS. Preemptive analgesia: treating postoperative pain by preventing the
establishment of central sensitization [review]. Anesth Analg. 1993;77:362-379.
ISI
| PUBMED
12. Treede R-D, Meyer RA, Raja SN, Campbell JN. Peripheral and central mechanisms of cutaneous hyperalgesia. Prog Neurobiol. 1992;38:397-421.
FULL TEXT
|
ISI
| PUBMED
13. Allen RT. New method for relieving postoperative pain following tonsillectomy. Arch Otolaryngol. 1953;57:86-89.
14. Goldsher M, Podoshin L, Fradis M, et al. Effects of peritonsillar infiltration on post-tonsillectomy pain: a
double-blind study. Ann Otol Rhinol Laryngol. 1996;105: 868-870.
15. Johansen M, Harbo G, Illum P. Preincisional infiltration with bupivacaine in tonsillectomy. Arch Otolaryngol Head Neck Surg. 1996;122:261-263.
FREE FULL TEXT
16. Broadman LM, Patel RI, Feldman BA, Sellman GL, Milmoe G, Camilon F. The effects of peritonsillar infiltration on the reduction of intraoperative
blood loss and post-tonsillectomy pain in children. Laryngoscope. 1989;99:578-581.
ISI
| PUBMED
17. Molliex S, Haond P, Baylot D, et al. Effect of pre- vs postoperative tonsillar infiltration with local anesthetics
on postoperative pain after tonsillectomy. Acta Anaesthesiol Scand. 1996;40:1210-1215.
ISI
| PUBMED
18. Orntoft S, Longreen A, Moiniche S, Dhal JB. A comparison of pre- and postoperative tonsillar infiltration with
bupivacaine on pain after tonsillectomy: a pre-emptive effect? Anaesthesia. 1994;49:151-154.
ISI
| PUBMED
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati  Twitter
What's this?
RELATED ARTICLE
Archives of Otolaryngology–Head & Neck Surgery Reader's Choice: Continuing Medical Education
Arch Otolaryngol Head Neck Surg. 2001;127(10):1289-1291.
FULL TEXT
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES
The Effects of Glossopharyngeal Nerve Block on Postoperative Pain Relief After Tonsillectomy: The Importance of the Extent of Obtunded Gag Reflex as a Clinical Indicator
Park et al.
Anesth. Analg. 2007;105:267-271.
ABSTRACT
| FULL TEXT
Inguinal Herniorrhaphy Under Monitored Anesthesia Care with Ilioinguinal-Iliohypogastric Block: The Impact of Adding Clonidine to Ropivacaine
Beaussier et al.
Anesth. Analg. 2005;101:1659-1662.
ABSTRACT
| FULL TEXT
Effect of Perioperative Administration of Ropivacaine With Epinephrine on Postoperative Pediatric Adenotonsillectomy Recovery
Park et al.
Arch Otolaryngol Head Neck Surg 2004;130:459-464.
ABSTRACT
| FULL TEXT
|
);
saline placebo compared with ropivacaine (*) or ropivacaine plus clonidine
(
). P values for overall 1-way analysis of
variance for VAS over time for pain at rest or following swallowing were .03
and less than .001, respectively.