Download Pectoral Nerves I and II Blocks in Multimodal Analgesia for Breast

ULTRASOUND ARTICLE
Pectoral Nerves I and II Blocks in Multimodal Analgesia for
Breast Cancer Surgery
A Randomized Clinical Trial
Ghada Mohammad Nabih Bashandy, MD, and Dina Nabil Abbas, MD
Background: The pectoral nerves (Pecs) block types I and II are novel
techniques to block the pectoral, intercostobrachial, third to sixth intercostals, and the long thoracic nerves. They may provide good analgesia during
and after breast surgery. Our study aimed to compare prospectively the
quality of analgesia after modified radical mastectomy surgery using general anesthesia and Pecs blocks versus general anesthesia alone.
Methods: One hundred twenty adult female patients scheduled for elective unilateral modified radical mastectomy under general anesthesia were
randomly allocated to receive either general anesthesia plus Pecs block
(Pecs group, n = 60) or general anesthesia alone (control group, n = 60).
Results: Statistically significant lower visual analog scale pain scores
were observed in the Pecs group than in the control group patients. Moreover, postoperative morphine consumption in the Pecs group was lower in
the first 12 hours after surgery than in the control group. In addition, statistically significant lower intraoperative fentanyl consumption was observed
in the Pecs group than in the control group. In the postanesthesia care unit,
nausea and vomiting as well as sedation scores were lower in the Pecs
group compared with the control group. Overall, postanesthesia care unit
and hospital stays were shorter in the Pecs group than in the control group.
Conclusions: The combined Pecs I and II block is a simple, easy-to-learn
technique that produces good analgesia for radical breast surgery.
(Reg Anesth Pain Med 2015;40: 68–74)
B
reast cancer is the most common cancer among women. In the
United States, 1 in 8 women develop breast cancer during
their lifetime.1,2 In Gharbiah, Egypt, increased breast cancer rates
have been recorded from 1999 to 2008. According to a recent epidemiologic study, higher breast cancer rates were expected between 2009 and 2015.3 Acute postoperative pain is an integral
risk factor in the development of chronic postmastectomy pain;
40% of women will have severe acute postoperative pain after
breast cancer surgery, whereas 50% will develop chronic postmastectomy pain with impaired quality of life.4,5 Regional anesthesia
techniques have provided better-quality acute-pain control and
subsequently less chronic pain.5,6 Proposed mechanisms for decreased persistent pain include decreased central sensitization
(wind-up) and lower incidence of opioid-induced hyperalgesia.7,8
Furthermore, effective acute pain control preserves immune
From the Department of Anesthesia and Pain Management, National Cancer Institute, Cairo University, Cairo, Egypt.
Accepted for publication August 20, 2014.
Address correspondence to: Ghada Mohammad Nabih Bashandy, MD, National
Cancer Institute, Cairo University, Fom Al-Khalij, KasrAleiny St, Cairo,
Egypt (e‐mail: [email protected]).
Funding from the National Cancer Institute, Cairo University, helped support
this work.
The work was presented as a poster at the WIP 2014 Congress at Maastricht, the
Netherlands, May 7 to 10, 2014.
The authors declare no conflict of interest.
Copyright © 2014 by American Society of Regional Anesthesia and Pain
Medicine
ISSN: 1098-7339
DOI: 10.1097/AAP.0000000000000163
68
function, both by suppressing the surgical stress response and by
decreasing the need for general anesthetics and opioids. Opioids,
especially morphine, inhibit both cellular and humoral immune
functions.9 This effect may be responsible for the higher rates of
postsurgical local recurrence and/or metastasis.10
Thoracic epidural block, thoracic paravertebral block (TPVB),
interpleural block, intercostal nerve block, interscalene block, and
wound infiltration have all been used in anesthesia and/or analgesia
in breast cancer surgery.11–16 Thoracic paravertebral block has been
shown to provide superior analgesia, and there is some evidence
suggesting decreased cancer recurrence rates with the use of
TPVB.17,18 Nonetheless, not all anesthesiologists feel comfortable
using such invasive techniques in breast cancer surgery. The pectoral nerve (Pecs) block, a less invasive novel technique described by
Blanco et al,19,20 is an interfascial plane block where local anesthetic is deposited into the plane between the pectoralis major muscle (PMm) and the pectoralis minor muscle (Pmm) (Pecs I block)
and above the serratus anterior muscle at the third rib (Pecs II
block). These novel techniques attempt to block the pectoral;
intercostobrachial; intercostals III, IV, V, VI; and long thoracic
nerves.19,20 Our study prospectively compares Pecs blocks in combination with general anesthesia and general anesthesia alone in
modified radical mastectomy (MRM) surgery. We hypothesized
that the Pecs blocks would provide superior postoperative analgesia
for patients undergoing mastectomy as compared with a control
group. Our primary outcome measure was visual analog scale
(VAS) pain scores on the first postoperative day in patients who
have preoperative Pecs block compared with those having general
anesthesia alone. Secondary measures were perioperative opioid
consumption, postoperative sedation, and postoperative nausea
and vomiting (PONV).
METHODS
After obtaining approval from Egypt’s National Cancer Institute Institutional Review Board, we conducted this prospective
randomized observer-blinded study from January 2013 to January
2014 in the National Cancer Institute of Egypt. A continuous sample of 120 American Society of Anesthesiologists (ASA) physical
status I and II female adult patients undergoing elective unilateral
MRM under general anesthesia were recruited Written informed
consent was obtained. Exclusion criteria included declining to
give written informed consent, history of allergy to the medications used in the study, contraindications to regional anesthesia
(including coagulopathy and local infection), prior breast surgery
except for diagnostic biopsies, and history of treatment for a
chronic pain condition and/or psychiatric disorder.
All patients included in the study were randomly assigned to
1 of the 2 groups: the Pecs group receiving Pecs blocks and general anesthesia (n = 60) and a control group receiving general anesthesia alone (n = 60). Group allocation was accomplished using
a predetermined random 1:1 sequence. All the recruited patients
were familiarized with VAS pain scoring and patient-controlled
analgesia (PCA).
Regional Anesthesia and Pain Medicine • Volume 40, Number 1, January-February 2015
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Regional Anesthesia and Pain Medicine • Volume 40, Number 1, January-February 2015
Preoperative Management
All patients were premedicated with 10 mg of oral diazepam
on the night of surgery. In the preoperative holding area, patients
were attached to standard ASA monitors, and intravenous (IV) access was obtained. Premedication with IV 1 to 2 mg of midazolam
and 10 mg of metoclopramide was administered to all patients.
The patients in the control group were then transferred immediately to the operating room, whereas the patients in the Pecs group
received an ultrasound-guided Pecs block and a 15-minute observation time prior to their transfer to the operating room. One investigator (G.M.N.B) did all the blocks for patients in the Pecs
group. Anesthesia management and data collection were performed by personnel blinded to the treatment group.
A broadband (5–12 MHz) linear array probe of eZono 3000
portable ultrasound system (eZono USA, Redmond, Washington)
was used, with an imaging depth of 4 to 6 cm. After cleaning the
infraclavicular and axillary regions with chlorhexidine, the probe
was placed below the lateral third of the clavicle, similar to what
is done when performing infraclavicular brachial plexus block
(Fig. 1). After recognition of the appropriate anatomical structures, the skin puncture point was infiltrated with 2% lignocaine,
then the block was performed by using a 20-gauge Tuohy needle.
The needle was advanced to the tissue plane between the PMm
and Pmm at the vicinity of the pectoral branch of the
acromiothoracic artery, and 10 mL of 0.25% bupivacaine was deposited (Figs. 2, 3, and 4). In a similar manner, 20 mL was deposited at the level of the third rib above the serratus anterior muscle
with the intent of spreading injectate to the axilla (Fig. 5).19,20
Intraoperative Management
Standard ASA monitors were attached to the patients. General anesthesia was induced with fentanyl 1 to 2 μg/kg, propofol
2 mg/kg, and cisatracurium 0.15 mg/kg, and the airway was
secured by endotracheal intubation. Anesthesia maintenance
consisted of 1 MAC of isoflurane in 50% oxygen and air with additional cisatracurium at the discretion of the anesthetist. Additional boluses of fentanyl were administered to maintain blood
Pectoral Nerve Blocks for Breast Surgery
pressure and/or heart rate values within or 20% lower than the
baseline values. Toward the completion of the surgery, paracetamol (Perfalgan) 1 g/100 mL IV infusion was started, and
isoflurane was discontinued. Neostigmine 0.05 mg/kg with atropine 0.02 mg/kg was administered IV for neuromuscular blockade reversal as clinically relevant. After responding to verbal
command, patients were extubated in the operating room then
transferred to the postanesthesia care unit (PACU).
Postoperative Management
In the PACU, patients were monitored with standard ASA
monitors. They were monitored for pain intensity using VAS pain
score, degree of sedation using the Ramsay sedation scale,21 and
incidence of PONV using a 5-point scale (0–4), where 0 = no nausea or vomiting, 1 = mild nausea, 2 = severe nausea, 3 = vomiting
once, and 4 = vomiting more than once.
When the reported VAS score was 3 or greater, a loading
dose of 5 mg of morphine was administered through slow IV
route. Then, a PCA was administered. The PCA pump (Graseby
3300 Pump; Smith Medical International, Ashford, Kent, UK)
was loaded with 1 mg/mL of morphine and set to deliver on demand bolus doses of 1 to 2 mL based on body weight with a 5minute lockout period. No background infusion was allowed. Oral
paracetamol (1 g) and ketoprofen (100 mg), to be administered 3
times daily, were prescribed to all patients as soon as oral feeding
was permitted. Ondansetron 8 mg IV was used to treat nausea and
vomiting. Patients with a score of 10 in the modified Aldrete scoring system were considered eligible for discharge to the surgical
ward.22 Patients were discharged from the hospital based on the
protocols of the surgical team, which included a pain score of less
than 3 without morphine and PONV and sedation scores of 0.
The following data were collected: intraoperative fentanyl
consumption; postoperative VAS pain scores (at 0, 3, 6, 9, and
24 postoperative hours); need for PCA morphine; time to PCA administration as well as morphine requirements at 0 to 4, 4 to 12,
and 12 to 24 postoperative hours; PONV scores; sedation scores;
PACU stay; and postsurgical hospital stay.
FIGURE 1. Image of the probe position and needle direction from medial to lateral during Pecs I block.30
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69
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Bashandy et al
Regional Anesthesia and Pain Medicine • Volume 40, Number 1, January-February 2015
FIGURE 2. Pecs I block ultrasound view. ax.a Indicates axillary artery; p., pectoral branch of thoracoacromial artery.
Statistical Analysis
All data analyses were carried out according to a preestablished analysis plan. Altman’s nomogram was used for simple size measurement. We believed that the distinction in VAS
pain scores would be significant if there was at least 1 point of difference between patients who received Pecs block as preemptive
analgesia before mastectomy versus the control group (variability
estimated from an interim analysis; SD, 1.8). Thus, assuming α =
0.05 and the power of the study at 0.80, a total sample size of 100
patients would be required (50 in each group). To compensate for
patients who dropped out, we had planned to enroll 120 patients.
The normality of distribution of the initial data was assessed using
Kolmogorov-Smirnov and Shapiro-Wilk W tests. The data that
followed a normal distribution pattern were analyzed using t test
for equality of means. Equality of variances was estimated using
Levene test. The data that did not follow the normal distribution
were analyzed using the nonparametric Mann-Whitney U test.
The Pearson goodness-of-fit χ2 test was used to analyze associations between independent variables. P < 0.05 was set as the cutoff point for significance. Statistical analyses were performed
using SPSS version 13.0 (SPSS Inc, Chicago, Illinois) and
Statistica version 8.0 (StatSoft Inc, Tulsa, Oklahoma).
RESULTS
Patient demographics and duration of surgery for both
groups were comparable (Table 1). Statistically significantly lower
VAS pain scores were observed in the Pecs group compared with
the control group in all test time periods (Fig. 6). In comparing
FIGURE 3. Ultrasound image of needle tip at the plane of Pecs I block between the 2 pectoral muscles (arrows indicate the needle).
70
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Regional Anesthesia and Pain Medicine • Volume 40, Number 1, January-February 2015
Pectoral Nerve Blocks for Breast Surgery
FIGURE 4. Local anesthetic spread between the 2 pectoral muscles. The arrow is pointing to the needle. LA indicates local anesthetic.
perioperative opioid needs, the intraoperative fentanyl requirements were found to be lower in the Pecs group than in the control
group (115 ± 28.56 μg and 252.5 ± 44.352 μg, respectively, with
P < 0.001). In addition, the total amount of postoperative morphine needed to keep VAS pain scores less than 3 was 2.9 ±
1.714 mg and 6.9 ± 1.861 mg in the Pecs and control groups, respectively, and the difference was found to be statistically significant (P < 0.001). The patients in the Pecs group used less
morphine in the first 12 hours postoperatively than did the control
group patients, but the morphine needs of the 2 groups were comparable in the succeeding 12 hours (Table 2). Only 12 of 60 patients in the Pecs group required morphine PCA based on the
protocol of the study, where an adequate VAS pain score of less
than 3 was maintained only by paracetamol and nonsteroidal
anti-inflammatory drug that were given to all patients in our study.
Conversely, 36 of 60 patients in the control group required PCA
morphine administration.
Postanesthesia care unit stay was statistically shorter in the
Pecs group than in the control group (14 ± 11 minutes and 28 ±
12 minutes, respectively, where P = 0.012). This finding may be
explained in part by lower VAS pain scores in the Pecs group, as
well as lower PONV scores (0.15 ± .366 vs 1.65 ± 0.875, with
P < 0.001). The reported lower sedation scores in the Pecs group
compared with those in the control group are an alternative explanation of shorter PACU stay in the Pecs group (2.10 ± 0.308 vs
3.20 ± 0.523, respectively, with P < 0.001).
Postsurgical hospital stay was shorter in the Pecs group than
that in the control group (P < 0.001). All patients in the Pecs
group were discharged from the hospital within 24 hours, whereas
in the control group, only 12 patients left within 24 hours, 42
FIGURE 5. A, Image showing external probe position during Pecs II block.30 B, Ultrasound view of Pecs II block (r. 3 indicates 3rd rib; serr.,
serratus anterior muscle; white line, needle path to deposit local anesthetic above serratus anterior muscle.
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Regional Anesthesia and Pain Medicine • Volume 40, Number 1, January-February 2015
Bashandy et al
TABLE 1. Demographic Data
Variable
Age, y
Weight, kg
Height, cm
Duration of surgery, min
Pecs Group (n = 60)
Control Group (n = 60)
P
48.65 (10.7)
75.96 (6.3)
163 (6.8)
110 (17)
50.47 (12.1)
74.34 (5.9)
162 (7.8)
109 (19)
0.74
0.14
0.84
0.34
Values are mean (SD).
P > 0.05 is statistically insignificant.
patients were discharged within 48 hours, and 6 patients stayed in
the hospital for more than 48 hours.
DISCUSSION
Lower pain scores were observed in patients undergoing
MRM with preemptive Pecs I and II blocks than in the controls.
Perioperative opioid use, including intraoperative fentanyl as well
as postoperative morphine, was lower in the Pecs group compared
with that in the control group. Our study also revealed lower
opioid-related adverse effects with lower sedation and PONV
scores in the Pecs group. Moreover, PACU and hospital stays were
shorter in the Pecs group compared with that in the control group.
To start performing the Pecs block, the neural supply of
structures involved in breast surgery must be well understood.
The pectoral nerves (PNs) show wide variability in their course.23
They are described in most textbooks as purely motor nerves, but
it was suggested that they also transport proprioceptive and nociceptive fibers as shown in other motor nerves.24 In some patients,
there might be additional innervations from the fourth intercostal
nerve.25 A meta-analysis of available literature showed that the lateral PN (LPN) arises most frequently with 2 branches from the
anterior divisions of the upper and middle trunks (33.8%) or as
a single root from the lateral cord (23.4%). The medial PN
(MPN) usually arises from the medial cord (49.3%), anterior division of the lower trunk (43.8%), or lower trunk (4.7%). The 2 PNs
are usually connected by the ansa pectoralis immediately distal to
the thoracoacromial artery.26 Hoffman and Elliott27 suggested
blocking the PNs to reduce chronic postoperative pain or muscle
spasm after mastectomy. A denervation point for PMm targeting
the neurovascular bundle containing the LPN deep to the PMm
was identified. This point is at distances of 2.81 ± 0.33 cm vertically from the medial third part of the clavicle and 8.12 ± 1.09
cm horizontally from the midsternal line.28 The MPN runs under
the Pmm. It crosses the Pmm in 62% of the patients to reach
the lower third of the PMm after piercing the 2 layers of the
clavipectoral fascia. In the remaining 38%, it is located at the lateral border of the Pmm.26 Ultrasound-guided injection of 10 mL
of the solution in cadavers was found to be sufficient in staining
all the medial and LPN branches without any proximal extension
to the cords of the brachial plexus.23
In MRM surgery, blocking the PNs alone is not enough. The
anterior divisions of the intercostal nerves from T2 to T6 and the
long thoracic and the thoracodorsal nerves should be blocked
FIGURE 6. Visual analog scale scores in both study groups in different time points. VAS-0: first VAS after recovery from general anesthesia.
VAS-3,VAS-6, VAS-9, VAS-24 are VAS at 3, 6, 9, 24 hours postoperatively, respectively.
72
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Regional Anesthesia and Pain Medicine • Volume 40, Number 1, January-February 2015
Pectoral Nerve Blocks for Breast Surgery
TABLE 2. PCA Morphine Requirements
Variable
Time to the first dose of morphine, min
No. PCA morphine demands
PCA morphine, mg
0–4 h
4–12 h
12–24 h
Pecs Group (n = 60)
Control Group (n = 60)
P
170 (11.2)
2.5 (1.2)
130 (14.7)
4.3 (1. 8)
0.008*
0.04*
0 (0–9)
1 (0–4)
2 (0–15)
4 (2–12)
4 (0–10)
2 (0–25)
0.02*
0.035*
0.519
Values are means (SD) or median and range (Q1–Q3). 0–4 h, 4–12 h, and 12–24 h are postoperative hours where 0 is time of PACU admission.
*P < 0.05.
also.20 The intercostal nerves lie at the back between the pleura
and the posterior intercostal membrane and run in a plane between
the intercostal muscles as far as the sternum. They give off lateral
branches that pierce the external intercostal and the serratus anterior muscles at the midaxillary line to give off anterior and posterior terminal branches. The lateral cutaneous branch of the second
intercostal nerve does not divide in the anterior and posterior
branches, and it is called the intercostobrachial nerve. The intercostal nerves also give anterior branches that cross in front of
the internal mammary artery and pierce the internal intercostals
muscle, the intercostal membranes, and the PMm to supply the
medial aspect of the breast.20,29 The long thoracic nerve arises
from C5 to C7, entering the axilla behind the brachial plexus resting on the serratus anterior muscle. The thoracodorsal nerve is a
branch of the posterior cord made up of the 3 posterior divisions
of the trunks of the brachial plexus. It follows the thoracodorsal artery and innervates the latissimus dorsi in the posterior wall of
the axilla.20
Blanco19 first described Pecs I block in 2011 as an interfascial
block to place local anesthetic into the plane between PMm and
Pmm. He targeted the LPN, which is consistently located adjacent
to the pectoral branch of the thoracoacromial artery between the
PMm and Pmm. In addition, Blanco19 stated that a catheter can
readily be placed into that interfascial plane. One year later, Blanco
et al20 described a second version of the Pecs block called modified
Pecs block or Pecs block type II, another approach aiming to block
the axilla and the intercostal nerves that are necessary for axillary
node dissection and wider excisions, respectively. In Pecs block
type II, 20 mL of local anesthetic has to be deposited above
the serratus anterior muscle. The local anesthetic would spread to
the axilla where the long thoracic nerve and lateral branches of
the intercostal nerves are found as they exit at the level of the
midaxillary line.20
Pérez et al also30 described a different approach for Pecs block
and reported decreased perioperative systemic analgesic requirements
and improved patient satisfaction in major and minor breast surgeries.
The ultrasound probe is placed below the outer third of the clavicle,
after identifying 4 structures: PMm, Pmm, thoracoacromial artery,
and cephalic vein; the needle is introduced in plane with the ultrasound probe from medial to lateral. They claimed that their approach
stays far from the pleura and blood vessels and avoids blocking the
needle path through the coracoid process.30
Pectoral nerves block was used in conjunction with TPVB in
an observational study. The researchers compared TPVB and sedation with and without a Pecs block for breast augmentation surgery.
Better postoperative analgesia and a lower requirement for sedation were observed in patients who received Pecs block.31 The
paravertebral space communicates with the epidural space, is close
to the pleural space, and contains supply arteries to the spinal cord;
hence, special precautions should be adopted while performing
© 2014 American Society of Regional Anesthesia and Pain Medicine
TPVB. Thoracic paravertebral block often becomes an epidural
block and may also result in total spinal anesthesia.32,33
The Pecs block is a combination of motor and sensory nerve
blocks. One advantage of Pecs block, requiring emphasis, is that it
is not associated with sympathetic block as are the TPVB and epidural blocks. On the other hand, intravascular injection into the
pectoral branch of the acromiothoracic artery is another possibility that could be considered. Complications should be easily
avoided with proper ultrasound training and searching for the right
pattern of spread of the local anesthetic.20
Limitations
One limitation of our study is that we did not have enough
time to assess the quality of the block before the induction of anesthesia. Moreover, blinding the patients to the received technique
by doing sham blocks to the control group would have made the
results more reliable. Another limitation is that, in an attempt to
minimize morphine consumption, we did not offer PCA morphine
except for patients with VAS scores of less than 3 when we should
have offered it to all patients upon arrival to the PACU or as soon
as they are alert enough to use it.
CONCLUSIONS
The Pecs blocks produce excellent analgesia when combined
with general anesthesia for breast surgery with axillary dissection.
They are simple, easy-to-learn techniques, having easily identifiable landmarks based on good anatomical and ultrasound knowledge, making them an excellent alternative to the conventional
thoracic paravertebral and neuraxial blocks for radical breast surgeries. Prospective randomized studies comparing Pecs blocks
with paravertebral and neuraxial blocks are recommended.
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