Keywords
postoperative pain - tonsillectomy - cautery
Introduction
The first description of a surgical technique for tonsillectomy was performed by Aulus
Cornelius Celsus, a Roman physician of the time of Christ, who extracted the tonsils
using just his fingers.[1] Currently, tonsillectomy is one of the most common surgical procedures in the world
and the most common in otolaryngology.[1]
[2] Over the past decade, there has been progress in surgical and anesthetic techniques
for tonsillectomy, resulting in faster surgeries with fewer complications.[3] Despite the evolution to what is currently considered a safe procedure, pain and
bleeding after tonsillectomy remain important surgical complications.[2]
[3]
[4]
Post-tonsillectomy pain is attributed to a combination of nervous irritation, inflammation,
and spasm of the pharyngeal muscles. Several strategies have been studied to achieve
better safety and efficacy in relieving postoperative pain, including pharmacologic
alternatives, surgical techniques, and cooling of the operative area.[3]
Objective
Evaluate the use of cooling the oropharynx intraoperatively to reduce postoperative
pain in tonsillectomy with the use of monopolar electrocautery in children.
Literature Review
Operative tonsillectomy pain is basically characterized by local tissue injury, which
releases histamine and inflammatory mediators that activate receptors of pain, causing
the transduction and transmission of pain information to the central nervous system
(CNS) and the process of neurogenic inflammation and vasodilatation determining extravasation
of plasma in the periphery.[5]
New surgical techniques for tonsillectomy recently have been introduced as options:
the harmonic scalpel and the coblation (plasma) and microdebrider. These devices operate
at a much lower temperature (60°C to 100°C) than electrocautery and thus are expected
to cause less thermal damage and less postoperative pain.[2]
In contrast with these new techniques, dissection with electrocautery, commonly used
as a method of choice, results in faster surgeries and promotes better hemostasis.
However, it generates more heat (400°C to 6,000°C) and thus produces greater thermal
damage in tissues and nerve endings of the tonsillar and peritonsillar areas, resulting
in greater pain, despite the high hemostatic power.[2]
[3]
Bipolar instruments (forceps and scissors) cause less thermal damage and less postoperative
pain compared with electrocautery, but reports have demonstrated a higher incidence
of postoperative pain and bleeding with these instruments compared with tonsillectomy
performed by cold dissection with the scalpel.[2]
Several techniques have been studied for the management of postoperative pain. Local
infiltration of anesthetic in the peritonsillar tissue to reduce post-tonsillectomy
pain has not shown conclusive results. Steroids, delivered via either systemic administration
or peritonsillar infiltration, was not effective in reducing pain.[3] Some other agents, such as fibrin glue and sucralfate, have been used for wound
healing, but with inconclusive results concerning pain reduction.[3]
The nerves are extremely sensitive to temperature, a fact that has promoted the implementation
of cryoanalgesia in pain control.[3]
[6] Cryoanalgesia can be applied percutaneously or directly on nerve endings with substances
at low temperatures, such as liquid nitrogen or saline solution at 0.9%. When these
endings are cooled to −200°C or less, they may be functionally inactive for 7 to 10
days due to production of crystals that degenerate the axon and its myelin structure
preserving intraneural collagen, allowing total regeneration in 4 to 5 weeks. In this
temperature, the other tissues do not suffer any damage. Thus, it was postulated that
cooling the oropharynx immediately after tonsillectomy can cause neuropraxia of the
exposed nerves, reducing inflammation and pain. This relatively simple technique does
not seem to be associated with complications.[3]
[7]
Horii et al[2] conducted a study with 189 patients under 16 years of age, aiming to compare the
post-tonsillectomy pain with bipolar scissors after cooling the pharyngeal mucosa
with traditional cold dissection. Indications for surgery were recurrent tonsillitis,
sleep apnea, and hypopnea obstructive syndrome and IgA nephropathy. The mucosa was
cooled by oropharynx irrigation with saline solution at a temperature of 4°C for 10
minutes after removal of the tonsils. As a result, they achieved significantly lower
levels of blood loss and postoperative pain assessed by visual analog scale (VAS)
of pain in the control group.
Materials and Methods
The study was conducted after approval by the Research Ethics Committee of the Red
Cross Hospital (HCV)–Branch of Paraná, from June to November 2012.
The inclusion criteria for surgery were obstructive symptoms or recurrent tonsillitis.
Subjects undergoing surgery for other reasons, as well as patients with mental or
physical disorders who were unable to be submitted to the protocols of anesthesia
and postoperative analgesia, were excluded from the study. Patients or caregivers
were given verbal and written information for study participation and also signed
the consent form.
Patients were randomized into a control group and a study group, and only one surgeon
performed the surgeries in the study. All the patients in the study immediately after
the procedure received a single dose of analgesics (dipyrone and ketorolac) and antiemetic
medication (ondansetron and dexamethasone).
Subcapsular dissection with hemostasis by electrocautery monopolar surgical technique
was chosen for all tonsillectomies performed in the study. The randomized patients
in the experimental group had the oropharynx cooled after tonsil dissection and hemostasis
for 10 minutes. The oral cavity was irrigated with 500 mL of 0.9% saline solution,
with a temperature between 5°C and 10°C, for 5 minutes and then aspirated through
the oropharynx. In the control group, no intervention was made after tonsil dissection
and hemostasis.
Immediately after the procedure, both groups received routine care. All patients received
postoperative analgesia with paracetamol every 6 hours and ketoprofen in cases of
severe pain as assessed by parents or by subjects crying. Patients were also instructed
to follow a standard soft/liquid diet after tonsillectomy.
Postoperative pain was assessed with the VAS. Pain was assessed with a 10-cm ruler
([Fig. 1]) ranging from no pain (0) to severe pain (10). The patients' parents began the register
on the day of surgery and were instructed to repeat this procedure twice a day, once
in the morning and again in the evening, at the same times, before the analgesics
use. Pain was evaluated for a period of 10 days after surgery. The follow-up of patients
was performed typically at 10 and 30 postoperatively days.
Fig. 1 Visual analog pain scale.
In addition to the pain scale, the absolute amount of ketoprofen used for the pain
relief, ranging from zero to three capsules due to the dosage, was recorded as complementary
data that could influence the evaluation of postoperative pain.
The data were evaluated between the groups by analysis of variance with p < 0.05 denoting significance using Statistica, Med Soft Inc., Tulsa, USA.
Results
The sample consisted of 66 patients age 1 to 12 years, 42 boys and 24 girls. After
randomization, 33 patients (age 1 to 10 years) were placed in the experimental group
and 33 patients (age 1 to 12 years) in the control group.
As shown in [Fig. 2], the post-tonsillectomy pain assessed by VAS was lower in the experimental group,
in which the cooling technique was used (an average of 4.35 in the control group and
3.42 in the experimental group), with statistically significant differences on days
0, 5, and 6 (p < 0.05). The values obtained in the experimental group were lower than the control
group on all days, except days 4 and 10, but it was not statistically significant.
Fig. 2 Average visual pain scalevalues.
In the pain assessment based on the need to use ketoprofen ([Table 1]), there was no statistically significant difference between the groups during the
study period. In the control group, the greatest day of ketoprofen use was day 7 (2.76 ± 0.33),
and this day also had the highest average in pain scale (6.3 ± 0.33). In the experimental
group, day 6 had the highest use of ketoprofen (2.89 ± 0.39), but the biggest pain
according to the VAS of pain, as well as in the control group, was on day 7 (5.33 ± 0.33).
Table 1
Assessing the need for ketoprofen
|
Day
|
Control group
|
Experimental group
|
|
|
Average
|
Standard deviation
|
Average
|
Standard deviation
|
p
|
|
0
|
1.33
|
0.23
|
1.3
|
0.33
|
0.033
|
|
1
|
0.56
|
0.39
|
0.76
|
0.33
|
0.063
|
|
2
|
0.33
|
0.33
|
0.34
|
0.25
|
0.078
|
|
3
|
1.33
|
0.33
|
0.56
|
0.33
|
0.0786
|
|
4
|
2.33
|
0.25
|
2.24
|
0.45
|
0.0763
|
|
5
|
2.33
|
0.33
|
2.34
|
0.38
|
0.01
|
|
6
|
2.33
|
0.39
|
2.89
|
0.39
|
0.009
|
|
7
|
2.76
|
0.33
|
2.56
|
0.33
|
0.063
|
|
8
|
1.23
|
0.25
|
1.67
|
0.45
|
0.067
|
|
9
|
0.57
|
0.33
|
0.78
|
0.25
|
0.087
|
|
10
|
0.33
|
0.4
|
0.78
|
0.33
|
0.089
|
Discussion
Numerous studies in the literature suggest that temperature is the most important
factor in preventing tissue damage and postoperative pain.[6] Horii et al[2] first demonstrated that surgical techniques for tonsillectomy that use some kind
of heat could reduce postoperative pain with some kind of cooling of the pharyngeal
mucosa when compared with the cold technique.
The advantages of a local cold stimulus, according to Sylvester et al,[6] include prevention of edema due to a decrease of the liquid inside the tissues,
reduced inflammation, decreased metabolism, and better control of bleeding. In our
study, we demonstrated that cooling the oropharynx results in clear and significant
reduction of post-tonsillectomy pain during the 10-day follow-up after surgery.
The mean values of the pain scale, in both groups, gradually decreased during the
first 3 days after surgery, then increased from the fourth day, with a peak of pain
on the day 7 and further reduction from day 8. This fact, as quoted by Cornejo et
al,[1] can be explained by the destruction of nerve endings in the tonsillar cavity promoted
by the heat of electrocautery; these endings regenerate in the following days, increasing
the perception of pain.
As an explanation for the similar ketoprofen consumption between groups, we hypothesized
that the availability of medication and guidance to caregivers to administer the anti-inflammatory
for possible cases of severe pain experienced by the patient, together with the existing
emotional bond, could promote the administration of medication as a way to prevent
pain, consciously or not, to prevent the patient's suffering.
Cryoanalgesia is a new technique for reducing post-tonsillectomy pain. Studies show
that its use results in clear and significant reduction of post-tonsillectomy pain
during the 10 days after surgery (28.3% decrease in the evaluation of the visual scale
of pain compared with the control group). These patients also returned to school or
work 4 days earlier, on average, than those who received no intervention. It has been
suggested that cryoanalgesia promotes a return to usual diet before the control group,
as well as less need to use analgesics.[3]
In our study, cooling after tonsillectomy resulted in a 21.4% reduction in the average
values obtained by VAS of pain. Few information is available in the literature about
what degrees of reduction in scale values for pain are necessary to be considered
clinically significant, with values ranging from 20 to 50%, depending on the initial
intensity of pain. We obtained a clinically important reduction in pain after tonsillectomy
with cooling of the oropharynx.
Concerning the limitations of our study, we can mention the exclusive analysis of
postoperative pain, not taking into consideration factors such as surgical time and
blood loss, which could be factors that cause increased postoperative pain due to
greater use of electrocautery. Another limiting factor to be considered is the subjectivity
of pain assessment by caregivers, especially in younger children who have not developed
adequate verbalization and cannot properly express the symptoms.
Conclusion
Our study demonstrated that the use of cooling in the oropharynx after tonsillectomy
with the monopolar electrocautery can promote a clinically important reduction in
postoperative pain, without additional complications, according to the assessment
made by an objective and validated scale of pain.
