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Preincisional Bupivacaine in Posttonsillectomy Pain Relief
A Randomized Prospective Study
Nilesh Raman Vasan, FRACS;
Scott Stevenson, FRACS;
Mark Ward, FRACS
Arch Otolaryngol Head Neck Surg. 2002;128:145-149.
ABSTRACT
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Objective To determine the effect of preincisional bupivacaine hydrochloride infiltration
on postoperative pain after tonsillectomy.
Design Prospective, randomized, double-blind clinical trial.
Setting A secondary/tertiary referral center in Christchurch, New Zealand.
Patients A volunteer sample of 70 patients, aged 16 to 42 years, with recurrent
tonsillitis. Seven patients were excluded.
Interventions After randomization, one group received 5 mL of 0.5% bupivacaine hydrochloride
in the peritonsillar space, with the patient under general anesthesia. The
other group received 5 mL of isotonic sodium chloride solution, with the patient
under general anesthesia. Both groups underwent surgery with a standardized
surgical and anesthetic technique.
Main Outcome Measures Postoperative pain was assessed with a visual analog scale at 15 minutes
and 1, 4, 12, 16, and 24 hours after the procedure. Postoperative analgesic
requirement, length of admission, and antiemetic requirement were also assessed.
Results No statistical difference was found between the 2 groups for postoperative
pain by means of the visual analog scale at any time interval, nor was any
statistical difference found for the other variables measured. A trend toward
less pain in the immediate postoperative period in the group receiving bupivacaine
was noted.
Conclusion No statistically significant benefit is found for use of preincisional
bupivacaine in tonsillectomy.
INTRODUCTION
THE ROLE of local anesthetic (LA) infiltration in tonsillectomy is controversial.
Studies have been published that support and refute the use of LA during tonsillectomy.
Proponents of LA infiltration claim a reduction in postoperative pain that
in some studies has shown a benefit up to 10 days postoperatively.1-2
Local anesthestic is thought to act by impeding noxious stimulation
of C-fiber afferent neurons, thereby diminishing the excitability of dorsal
horn neurons.1 The excitability produced by
nociceptive stimuli may contribute to postoperative pain, even when procedures
are performed under general anesthesia.1 Confirming
the benefit of preincisional LA analgesia statistically has been difficult.
Tonsillectomy is known to cause severe pain postoperatively. The pain
affects the patient's nutrition, ability to return to work or school, discharge
from the hospital, and satisfaction with the whole process. Our study was
designed to determine whether LA has an effect on postoperative pain after
tonsillectomy. Only older teenagers and adults were recruited to ensure that
participants could understand and complete a visual analog scale (VAS). We
excluded children to avoid observer bias when assessing pain.
PATIENTS AND METHODS
Ethical approval was obtained from the Canterbury Ethic Committee (Christchurch,
New Zealand); 70 patients, aged 16 to 42 years, were recruited for the study.
All patients had attended an otolaryngology outpatient clinic with a history
of recurrent tonsillitis. Patients with allergies, those with bleeding disorders,
those using regular analgesic medication, and those with significant comorbidities
were excluded. Patients were enrolled between May 1, 1998, and September 30,
1999.
All patients gave consent and were instructed on how to complete a VAS
before surgery. A 100-mm horizontal-line VAS was used, where 0 mm represented
no pain, and 100 mm, the worst pain imaginable. Patients were given a new
VAS at each testing interval and were instructed to mark on the line the approximate
level of their pain at that moment. The VAS has been found to be reliable
and easily used in a number of studies.3-4
A standard anesthetic protocol was constructed for the study patients
and administered by a number of anesthetists. The protocol consisted of the
following:
- Premedication: acetaminophen, 20 mg/kg (up to 1.5
g) orally 40 minutes to 1 hour preoperatively; intravenous induction: fentanyl
citrate (1 µg/kg), propofol (2 to 3 mg/kg), and mivacurium chloride
(0.1-0.2 mg/kg).
- Maintenance: oxygen and nitrous oxide in a ratio
of 1:2 (oxygen saturation >94%), isoflurane (0.25%-2.00% end-tidal), and morphine,
0.1 mg/kg (maximum, 10 mg).
- Antiemetic: cyclizine hydrochloride, 1 mg/kg (maximum,
50 mg).
- Recovery: analgesia: morphine (0.02 mg/kg as needed
to every 5 minutes if pain score
 60 mm and respiratory rate 8/min);
antiemetic: ondansetron (0.15 mg/kg as needed 1 time for nausea or vomiting;
maximum, 8 mg).
The tonsillectomy was performed by 1 of 3 surgeons (N.R.V., S.S., and
M.W.) with a standardized blunt dissection technique. No concurrent procedures
were performed. All patients had been randomized into the LA group or placebo
group (isotonic sodium chloride solution) by means of a sealed envelope to
determine which solution was required before they entered the operating room.
Surgeon, patient, anesthetist, and recovery and ward staff were all blinded
to the solution used.
After induction and positioning of the patient, the tonsil was medialized
by means of Denis Browne forceps. The lateral surface of the tonsil was identified
submucosally. With the use of an aspiration-injection technique, 3 mL of a
0.5% bupivacaine hydrochloride solution (or isotonic sodium chloride solution
in the control group) was injected into the peritonsillar area in approximately
the same position where a peritonsillar abscess would be drained. Two milliliters
of solution was injected into the peritonsillar space at the upper pole (total,
5 mL on each side). After a wait of 5 minutes, a blunt dissection snare technique
was used to remove the tonsils, with hemostasis achieved with silk ligatures
only.
Patients' pain scores were assessed by means of a VAS at fixed intervals
after the end of the procedure. These times were 15 minutes and 1, 4, 12,
16, and 24 hours after extubation. Patients were blinded to their previous
VAS scores. Postoperative analgesia was divided into regular medication and
rescue analgesia. Regular medication was started 4 hours after premedication
and consisted of acetaminophen (1 g orally or rectally every 4-6 hours) or
codeine phosphate (30 mg orally every 6 hours). The rescue analgesia was administered
by nursing staff according to a 0-to-10 verbal pain score, in which less than
3 indicated no extra medications; 3 to less than 6, codeine phosphate given
as needed, 30 mg orally every 6 hours; and 6 or more, intramuscular morphine
every 4 hours. Metoclopramide hydrochloride was given as an antiemetic on
an as-needed basis. Outcome measures included VAS, analgesic requirement (recovery
and ward), duration of admission, and antiemetic requirement. This study did
not assess blood loss during tonsillectomy. A note regarding intraoperative
difficulty was also made, as cases where interval tonsillectomy was being
performed (after drainage of a peritonsillar abscess) were included in the
study.
Statistical analyses were performed with SAS for Windows (Version 6.12;
SAS Institute Inc, Cary, NC). The VAS scores of the placebo group and the
treatment group were compared with a repeated-measures analysis of variance
model. Analysis between continuous variables was done with either an unpaired t test or a Mann-Whitney test. The  2 tests
(with Yates correction) were used for categorical data. Results are expressed
as means and SDs where appropriate, or as medians and ranges. To detect a
difference between the 2 groups of 15 mm and to have a power greater than
0.81 (SD of 15 mm), 30 patients in each group were required, assuming a 2-tailed
significance test at  = .05.
RESULTS
Seventy patients were randomized into the LA and placebo groups. Seven
patients were excluded because of breaches of anesthetic protocol (2 patients),
postoperative analgesia protocol (2 patients), and changes in surgical technique
(3 patients). A total of 31 patients (8 male) received LA. Thirty-two patients
(9 male) received isotonic sodium chloride solution. The mean (SD) age was
23.4 (6.7) years and 23.1 (6.4) years for the LA and placebo groups, respectively.
Of the 63 patients in the study, only 46 patients had a VAS completed at each
of the recording times. Data were missed because the patient was asleep and
the VAS recording was not obtained, or because of nursing error. The number
of VAS scores obtained for each time and the mean values recorded are shown
in Table 1.
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Table 1. Mean VAS Scores for Placebo and LA Groups After Extubation*
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Results between the 2 groups for each time were compared by means of
a repeated-measures analysis of variance. No statistical difference between
the 2 groups was found (F = 3.03, P = .09). At 15
minutes, the LA group had a lower mean score (45 mm) than the placebo group
(60 mm), but this was not significant. The overall mean for the LA group was
less (36 mm) than that for the placebo group (42 mm), but again this was not
significant.
Figure 1 shows a trend toward
less pain in the LA group that was not statistically significant. All other
variables (Table 2), including
postoperative analgesic consumption, time to first codeine tablet, length
of admission, and antiemetic requirement, showed no significant difference
between the 2 groups. No patient suffered any adverse effect from LA infiltration
(ie, respiratory obstruction or local anesthetic toxic effects).
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Mean visual analog scale (VAS) score for the placebo and local anesthetic
(LA) groups during 24 hours.
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Table 2. Baseline Characteristics and Medications*
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COMMENT
This double-blinded, randomized, prospective study did not demonstrate
any statistical benefit with preincisional bupivacaine treatment in patients
undergoing tonsillectomy. The hypothesis behind preemptive analgesia is to
prevent or reduce any "memory" of the painful stimulus in the nervous system.5 Subsequently, this reduction in pain memory should
lower any subsequent analgesia needs.5 In this
study, we were unable to confirm this hypothesis.
In this study, 3 surgeons performed tonsillectomy by means of a fixed
anesthetic protocol, injection method, and operative technique. The method
was constructed to closely resemble techniques in common practice in New Zealand.
The VAS and postoperative analgesic requirements failed to show any benefit
with LA.
Many studies have addressed the question of the effect of LA in tonsillectomy,
with a marked variance in results. Jebeles et al2
assessed adenotonsillectomy in 1993 and found a statistically significant
improvement in postoperative pain in 22 children with the use of LA. A reduction
in pain in some cases within the LA group persisted until day 10. The same
authors in 1991 had shown similar results with LA in 14 children undergoing
tonsillectomy.1 Unfortunately, these studies
suffer from inclusion of children and small sample sizes and lack detail regarding
injection technique. Pain is a subjective and complex expression, and its
assessment depends on personal experience, social and ethnic factors, and
anxiety level as well as the patient's ability to describe the type and degree
of pain on the basis of some frame of reference. The inclusion of children
into such studies makes the assessment of pain even less precise. Our study
was constructed to minimize the number of variables; only an older teenaged
and adult patient population was used, who completed their own VAS.
Dynamic assessments of pain, such as drinking water or opening the jaw,
have been used in past studies, in an attempt to measure pain objectively.2, 6 We elected to assess the patients'
pain by using a VAS at repeated intervals, the overall score of which would
represent the contribution of constant and dynamic pain.
The majority of previous studies used electrocautery as the dissection
method; however, recent evidence has shown that an electrocautery dissection
technique increases postoperative morbidity in terms of pain, otalgia, and
poor diet when compared with blunt dissection technique.7-8
The electrocautery dissection method used in other studies may have altered
their results.
The peritonsillar region is innervated by fibers from the glossopharyngeal
nerve, the lesser palatine nerves, and the lingual nerve.3
The premise for LA injection is to obtain blockade of these fibers. Descriptions
of injection technique and amount of solution injected have been variable.
In Jebeles and coworkers' initial 1991 article, no mention of injection technique
was included.1 In our study, 5 mL of 0.5% bupivacaine
hydrochloride was injected into each peritonsillar space. Our assumption was
that a high volume of solution within this area would anesthetize the multiple
pain fibers supplying the tonsillar bed. In a recent study,9
the injection technique attempted to block the glossopharyngeal nerve and
lesser palatine nerve contributions to the fossa. That group did not mention
the amount of LA administered at each site, however. In 2 studies by Schoem
et al,6, 10 small volumes of LA
were used. In their adult study, only 1.8 mL of 0.5% bupivacaine hydrochloride
was used. There was a concern in their study regarding toxicity, but the dose
they used fell well short of the 225-mg adult toxic dose. Violaris and Tuffin11 assessed LA in patients by using the contralateral
side as a control. We believe assessing pain in this way after tonsillectomy
is difficult.
Studies investigating the role of LA in tonsillectomy are listed in Table 3. From reviews of similar studies,
no conclusions regarding LA can be made. Ågren et al16
published an article comparing tonsillectomy performed with the patient under
general anesthesia and LA. The patients in the LA group tolerated the procedure
well and demonstrated less postoperative pain than did the general anesthesia
group. Obviously, LA must exert an effect if tonsillectomy can be performed
when the patient is awake. During our study, all surgeons noted that preoperative
injection of fluid in the peritonsillar space aided in dissection by the blunt
dissection technique.
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Table 3. Studies Investigating the Role of LA in Tonsillectomy*
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Currently, the benefit of LA in controlling pain after tonsillectomy
performed with the patient under general anesthesia remains debatable. The
difficulty lies in our limited ability to assess pain accurately with the
measures we use now. Pain is a multifaceted symptom, influenced by the patient's
previous experiences and expectations, as well as his or her peripheral neural
inputs. The question of what is a significant reduction in pain has yet to
be determined. There is no clear advice in the literature on what is an acceptable
reduction in pain, measured with a VAS, in any situation. Most authors use
a 100-mm VAS; some then seek a difference of 20 mm between the means of the
2 groups, whereas others accept a difference of 15 mm. Many previously published
articles lack power.17 In our study, a difference
of 15 mm between the means of the 2 groups gives a power of 0.81. Research
into ways to improve tonsillectomy continues to be troubled by issues of this
nature, as institutions seek to evaluate different operative techniques, anesthetic
protocols, the benefit of perioperative corticosteroids, the benefit of perioperative
antibiotics, and the use of nonsteroidal anti-inflammatory drugs. Randomized,
prospective, double-blind studies in all of these areas are limited in number;
research using the structures outlined in this study may give answers to these
issues.
AUTHOR INFORMATION
Accepted for publication September 4, 2001.
Preliminary results were presented at the Annual Scientific Meeting
of the New Zealand Society of Otolaryngology and Head and Neck Surgery, Apia,
Samoa, September 7, 1999.
We thank the otorhinolaryngology nursing staff in the operating room
and the ward in Christchurch Hospital, Christchurch, for helping to obtain
the VAS scores for these patients. Special thanks to Patrick Graham, Jamie
Sleigh, MD, and Teena West for the statistical analysis.
Corresponding author: Nilesh Raman Vasan, FRACS, Department of Otolaryngology–Head
and Neck Surgery, Glasgow Royal Infirmary, 84 Castle St, Glasgow G4 0SF, Scotland
(e-mail: nileshvasan{at}aol.com).
Reprints: Scott Stevenson,
FRACS, Department of Otolaryngology–Head and Neck Surgery, Christchurch
Public Hospital, Private Bag, Christchurch, New Zealand (e-mail: entdocs{at}xtra.co.nz).
From the Department of Otolaryngology–Head and Neck Surgery,
Christchurch Public Hospital, Christchurch, New Zealand (Drs Vasan, Stevenson,
and Ward); and Department of Otolaryngology–Head and Neck Surgery, Glasgow
Royal Infirmary, University NHS Trust, Glasgow, Scotland (Dr Vasan).
REFERENCES
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1. Jebeles JA, Reilly JS, Gutierrez JF, Bradley EL Jr, Kissin I. The effect of pre-incisional infiltration of tonsils with bupivacaine
on the pain following tonsillectomy under general anesthesia. Pain. 1991;47:305-308.
FULL TEXT
|
ISI
| PUBMED
2. 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;25:149-154.
FULL TEXT
|
ISI
| PUBMED
3. Revill SI, Robinson JO, Rosen M, Hogg MIJ. The reliability of a linear analogue for evaluating pain. Anaesthesia. 1976;31:1191-1198.
ISI
| PUBMED
4. Chapman CR, Casey KL, Dubner R, Foley KM, Gracely RH, Reading AE. Pain measurement: an overview. Pain. 1985;22:1-31.
ISI
| PUBMED
5. 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
6. Schoem SR, Watkins GL, Kuhn JJ, Alburger JF, Zim KZ, Thompson DH. Control of early postoperative pain with bupivacaine in adult local
tonsillectomy. Arch Otolaryngol Head Neck Surg. 1993;119:292-293.
FREE FULL TEXT
7. Nunez DA, Provan J, Crawford M. Postoperative tonsillectomy pain in pediatric patients: electrocautery
(hot) vs cold dissection and snare tonsillectomy—a randomized trial. Arch Otolaryngol Head Neck Surg. 2000;126:837-841.
FREE FULL TEXT
8. Atallah N, Kumar M, Hilali A, Hickey S. Postoperative pain in tonsillectomy: bipolar electrodissection technique
vs dissection ligation technique: a double-blind randomized prospective trial. J Laryngol Otol. 2000;114:667-670.
ISI
| PUBMED
9. El-Hakim H, Nunez DA, Saleh HA, MacLeod DM, Gardiner Q. A randomized control trial on the effect of regional nerve blocks on
immediate posttonsillectomy pain in adult patients. Clin Otolaryngol. 2000;25:413-417.
FULL TEXT
|
ISI
| PUBMED
10. Schoem SR, Watkins GL, Kuhn JJ, Thompson DH. Control of early postoperative pain with bupivacaine in pediatric tonsillectomy. Ear Nose Throat J. 1993;72:560-563.
PUBMED
11. Violaris NS, Tuffin JR. Can post-tonsillectomy pain be reduced by topical bupivacaine? double
blind controlled trial. J Laryngol Otol. 1989;103:592-593.
ISI
| PUBMED
12. Stuart JC, MacGregor FB, Cairns CS, Chandrachud HR. Peritonsillar infiltration with bupivacaine for paediatric tonsillectomy. Anaesth Intensive Care. 1994;22:679-682.
ISI
| PUBMED
13. Johansen M, Harbo G, Illum P. Preincisional infiltration with bupivacaine in tonsillectomy. Arch Otolaryngol Head Neck Surg. 1996;122:261-263.
FREE FULL TEXT
14. 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
15. Ørntoft S, Løngreen A, Møiniche 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
16. Ågren K, Engquist S, Danneman A, Feychting B. Local versus general anaesthesia in tonsillectomy. Clin Otolaryngol. 1989;14:97-100.
FULL TEXT
|
ISI
| PUBMED
17. McQuay H, Moore A. Pre-emptive analgesia: a systematic review of clinical studies: 1950-1994. In: An Evidence-Based Resource for Pain Relief. Oxford, England: Oxford University Press; 1998:164-171.
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