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Educated Hand Publishing LLC 
“The Science Behind the Art” 
Volume 6 - No. 4 2018 

Anesthesia eJournal - Online
ISSN 2333-2611

Page 18

Ultrasound-Guided INTRAPEC Injection for Breast Surgery: A Novel Solution for 
Surgical Field Improvement During Electrocautery and Implantation and for Postoperative 
Pain and Muscle Spasm Reduction for Breast Surgery
Jonathan P Kline, MSNA, CRNA

Affiliation:
Director of Education at Twin Oaks Anesthesia

Funding/Conflict of Interest Disclosure: 
None 
Acknowledgment 
We gratefully acknowledge Dr. Wayne Lee MD. for supporting this effort into new territory.

KEYWORDS: INTRAPEC, Ultrasound, Spasm reduction, Electrocautery

INTRODUCTION
Regional anesthetic techniques for plastic surgery present a particular set of challenges for anesthesia providers. Two 
recognized issues are the complex, wide, and sometimes not well described pain generators from the extensive areas involved 
with plastics procedures and the risk of LAST (local anesthetic systemic toxicity). The latter is arguably the result of 
additional doses of local anesthetics administered by surgeons in the form of tumescent fluid. For the past several years, PECS 
1 and 2 blocks targeting the pectoral musculature have gained popularity as effective, opioid-sparing, multimodal pain-
reducing techniques for analgesia for breast and anterior trunk surgical pain. The techniques continue to gain momentum 
for their ease of placement and safety, compared with prior techniques such as thoracic epidural and paravertebral blocks. In 
theory, the PECS 1 technique, involving ultrasound-guided placement of a local anesthetic between the pectoralis major and 
minor, should denervate the muscle group, reducing spasm and irritation caused by surgical manipulation and subsequent 
placement of expanders or implants. However, during pocket creation, these muscle planes are violated and may cause the 
complete release of the carefully placed local anesthetic, dramatically altering its expected duration of action.
Like all other nerve block techniques, the PECS 1 block does not cause intramuscular flaccidity during electrical dissection 
(electrocautery). This leakage of the local anesthetic away from the target nerves will ultimately reduce postoperative pain and 
spasm control. This spasm of the muscle has been a source of contention between our surgical colleagues and anesthesia since 
surgery with muscle relaxants began. The spasm and muscle contraction of the pectoralis major during the dissections and 
space creation for implantation remains problematic, despite denervation occurring at the myoneural junction through the 
PECS 1 technique.
It is theorized that an ultrasound-guided injection of the pectoralis major muscle, done well ahead of the surgical dissection 
and space creation, might improve pectoralis muscle rigidity and spasm and potentially lessen trauma and bleeding during 
surgical techniques involving implantation. This may improve surgical field conditions during this phase of surgery and 
potentially reduce pain, spasm, and any need for intravenous muscle relaxants. It is also theorized that this technique may 
improve postoperative pain outcomes as a direct result of reduced muscle confrontation leading to trauma and spasm that 
occur during surgery.

Abstract
This article introduces a novel ultrasound-guided injection called the INTRAPEC technique as a solution to the specific 
problem of intraoperative pectoral major muscle spasm during electrocautery and manipulation. The technique is a cost-
effective, nonparenteral method for improving the surgical field during pectoral major isolation and subsequent implant 
placement. The technique may have added benefits such as a significant reduction in surgical complexity causing trauma 
and bleeding and significant reductions in postoperative pain and muscle spasm.

AEJ



Anesthesia eJournal          www.anesthesiaejournal.com
Volume 6 - No. 4 2018 Page 19

BACKGROUND
Intramuscular injections for the relief of pain and spasm are 
not a new concept. Pain management providers use a range of 
such techniques for a variety of ailments. Examples include 
intramuscular injections for the relief of piriformis syndrome, 
iliotibial band release, and various posterior trunk musculature 
injections for trigger point treatment. These injections share 
commonalities that are all relieved by the injection of local 
anesthetic. Additionally, they all involve elements of pain and 
spasm reduction, and the need for analgesic medicines. It is 
also possible that the evolution of chronic pain following breast 
reconstruction may originate from spasm and irritation of the 
pectoral compartment containing the medial and lateral pectoral 
nerves by the implant itself. Surgical denervation of neuroma 
secondary to this pain syndrome is a common element for certain 
breast reconstruction procedures, sacrificing sensation in most 
cases and function in others. In many cases, this intramuscular 
injection can release spasm and pain. It is suggested that 
infiltration of the pectoralis major muscle (INTRAPEC) 
can reduce the spasm of the pectoral major muscle during 
electrocautery and potentially into the recovery phase.
REVIEW OF THE LITERATURE
A PubMed (National Library of Medicine) search using 
the keyword “pectoral muscle injection” was performed and 
yielded several relevant articles. Many of the articles suggested 
using the PECS blocks for acute and chronic pain treatment 
following breast surgery. Interestingly, several articles reported 
postoperative treatment of existing pectoralis major muscle 
spasms with intramuscular injections of botulinum toxin type A 
(Botox-A). However, we found no articles in which a preoperative 
ultrasound-guided intramuscular injection was used directly 
for the purpose of spasm reduction during surgery or to reduce 
postoperative pain.
In 2011 O’Donnell and colleagues successfully treated a patient 
with persistent post-breast-surgery pectoral muscle spasms 
with an intramuscular injection.1 This is one example of use of 
botulinum toxin type A (Botox-A) treatment for pectoral muscle 
conditions related to surgery suggesting proof of concept for an 
intramuscular injection. Govshievich and colleagues reported a 
case presentation involving, again, postoperative pectoral muscle 
pain after breast surgery.2 In that case, the authors used the 
novel PECS 1 block as a diagnostic measure to more accurately 
identify the pain generator for this persistent pain. The PECS 1 
block was done using ultrasound with symptom relief. Shin and 
colleagues described combination intramuscular injections of 
the subscapularis and pectoralis major muscles for the relief of 
postmastectomy shoulder pain.3 They found that postmastectomy 
patients benefitted from this combination technique. Their 
technique described an intramuscular injection performed under 
ultrasound. However, again, it targeted postoperative treatment 
options for these persistent symptomatic patients. We found 
no mention of preoperative placement.3 In 2014 Leiman and 
colleagues reported on the early use of liposomal bupivacaine 
(Exparel) in an ultrasound-guided PECS 1 block for the 
management of postoperative pain after breast surgery.4 The 
technique involved the placement of a local anesthetic in the 
fascial plane between the pectoralis major and minor targeting 
the medial and lateral pectoral nerves. However, note that at the 

time of this writing, liposomal bupivacaine (Exparel) is currently 
cleared only for infiltration type regional blocks but now includes 
interscalene “nerve blocks”. This is an important distinction 
specific to the PECs 1 approach because  although targeting the 
medial and lateral pectoral nerves, it's accomplished by an 
infiltration of local anesthetic between the fascial planes created 
by the pectoral major and minor muscles. Despite this limitation 
in the US, there are many articles that have described Exparel’s 
safe and effective use in nerve blocks, such as the median and 
lateral pectoral nerve blocks in the PECs 1 approach.  Finally, 
Trignano et al reported on the use of an injection of the pectoral 
muscle, using botulinum toxin type A (Botox-A), for relief of 
pectoral muscle spasms in 2011.5 Although the team reported 
favorable results of the intervention, the pectoral muscle was used 
as a flap for head and neck surgery, which is not exactly in league 
with this topic. However, mention of the technique is warranted 
to support proof of concept.
PATIENT PRESENTATION
The surgeon and patient agreed to this technique being performed 
in the office-based outpatient surgical center. The patient was 
a 20-year-old woman, American Society of Anesthesiologists 
(ASA) category 1, who was void of any comorbidities or 
prescribed home medications. She denied any prior surgical 
exposure, specifically breast procedures. She denied any allergies or 
illicit drug or alcohol use and was void of any physical or mental 
disabilities. The only discomfort she stated before the procedure 
was menstrual pain, which she characterized as moderate to 
severe. She presented to the office-based surgery suite with 
desire for bilateral breast augmentation. She was informed of the 
anesthesia plan involving general anesthesia with laryngeal mask 
airway, in combination with PECS 1, PECS 2, and the additional 
technique we termed INTRAPEC injection. She demonstrated 
understanding of the risks and benefits and agreed to proceed.
TECHNIQUE
Following explanation of the procedure to the patient, and prior 
approval from the surgeon, the patient positioned herself on the 
operating room table. An institutional time out was performed, 
and monitors and oxygen were applied. The patient’s baseline vital 
signs were recorded, preoxygenation was employed, and general 
anesthesia with placement of a laryngeal mask airway were easily 
performed. The skin was prepped with sterile chlorhexidine, 
and sterile single-use gel was applied to the suspected areas of 
interest. A probe cover (SaferSonic, Highland Park, IL) was 
applied and the ultrasound image optimized. The ultrasound-
guided INTRAPEC technique was accomplished with the use 
of a high-frequency linear transducer (Terason L15 paired with a 
Terason 3300 ultrasound system, Burlington, MA). The probe was 
positioned transverse over the anterior chest below the clavicle, 
beginning at the origin of the pectoral major medially, similar to 
that described by Blanco for the PECS 1 technique. The inferior 
and posterior border was identified sonographically and was 
specifically targeted. An 80-mm, 22G echogenic needle (Pajunk, 
Germany) was introduced from medial to lateral into this discrete 
muscle region, following placement of the PECS 1 block. The 
goal of the injection was to concentrate local anesthetic to the 
aponeurosis of this anterior and inferior border of the pectoral 
major muscle. Doppler mode was engaged to assist in the location 
of the vasculature in the region of interest. Following aspiration 



Anesthesia eJournal                         www.anesthesiaejournal.com
Volume 6 - No. 4 2018 Page 20

and complete expulsion of all air from the needle, connective 
tubing, and syringe, a mixture of lidocaine 2% and ropivacaine 
0.5% was infiltrated. A total volume of 15 mL per muscle was 
placed. The injection was safely performed in a medial to lateral 
fashion, promoting safety by directing the needle away from the 
deeper thoracic structures.
See Figure 1 for an actual patient ultrasound image of the 
INTRAPEC procedure. The Figure shows the right-sided 
INTRAPEC technique. The needle is correctly placed into the 
anterior/inferior border of the pectoral major muscle.  
Figure 2 shows the ultrasound-guided INTRAPEC injection 
being performed. Figure 3 is an illustration of an ultrasound-
guided INTRAPEC injection.

Figure 1. Ultrasound image of the INTRAPEC procedure. 

Figure 2. Performance of the ultrasound-guided INTRAPEC 
injection. Note the medial to lateral, in-plane, needle direction.

Figure 3 is an illustration of an Ultrasound Guided 
INTRAPEC injection.

RESULTS
We report 2 aspects of this technique, the results from the 
surgeon’s experience during electrocautery and implantation, and 
the patient’s experience of pain after surgery. The surgeon stated 
that the creation of a surgical pocket was considerably easier and 
was accomplished without unpredictable muscle contraction 
during periods of electrocautery or manipulation via the lighted 
retractor. Additionally, the surgeon stated that the surgical field 
was more easily maintained free of muscle spasm and bleeding. 
This seemed to promote ease of implant placement. The surgeon 
reported favorable results and was agreeable to reproducing the 
technique on future cases. The patient reported only “pressure” 
from the surgical procedure; however, she complained of intense 
menstrual pain. She also stated that she had more pressure-like 
discomfort to the right breast than to the left. It was clear that 
the incisional and surgical region was not causing the patient 
discomfort. However, she was given 1 oxycodone orally, per the 
surgical postoperative regimen, to ease her abdominal discomfort 
before her ride home. In the immediate post-anesthesia care unit 
area, and on postoperative day one, she had no pectoral muscle 
spasms and needed no pain medication for her surgical regions.
DISCUSSION
We made observations during the placement of the INTRAPEC 
injection. First, the infiltration can be easily accomplished 
immediately following the PECS 1 block, as the needle is in 
nearly the correct position at that time. This suggests ease of 
placement and a small learning curve for those already using the 
PECS 1 block. During the surgical procedure, specifically, during 
the dissection and pocket creation of the pectoral major muscle, 
extremely little muscle contraction was seen during electrocautery. 
When asked how the pocket creation was compared with similar 
patients with similar presentations, the surgeon stated, “it was 
like the muscle was completely paralyzed.” This notion alone, 
that the problem of muscle spasm during electrocautery could be 
significantly improved with the simple addition of local anesthetic 
represents a bold step forward for both anesthesia providers and 
surgeons. This opens the door to more ultrasound-guided regional 
injections for a variety of purposes, potentially making optimal 
surgical fields less reliant on intravenous muscle relaxants.
We recognize some limitations and drawbacks from the addition 
of the ultrasound-guided INTRAPEC injection technique. 
The first element is the careful observation of the total dose of 
local anesthetic and potential of LAST. This element should be 
carefully considered because it is unique to this patient population 
and plastic surgery regarding the addition of tumescent fluid. 
The addition of tumescent fluid commonly incorporates larger 
volumes of local anesthetics as a part of the surgical regimen. 
Because the INTRAPEC technique is likely to be added to 
existing techniques such as the PECS 1 and 2 blocks, or other 
truncal techniques, this total dose should be carefully considered. 
Muscle relaxation facilitated by local anesthetics is likely 
associated with a high concentration of local anesthetics; thus, 
careful consideration of total dose is advised.
The potential for disastrous needle misadventure should also 
be mentioned. In novice hands, this technique may pose 
significant complications to the patient in the form of structure 
violation. This can lead to conditions such as cardiac tamponade, 
pneumothorax, or large vessel puncture, such as to the subclavian 



artery or vein. However, a more likely scenario might be puncture 
of a smaller vessel known to be in this region, such as the 
thoracoacromial artery. This artery is reliably found on ultrasound 
between the pectoralis major and minor during the PECS 1 
block.
It is possible for the surgeon to simply inject the inferior anterior 
border during dissection or under direct visualization following 
exposure. However, the delayed onset of the effect of this injection 
on reducing spasm and reactivity to electrocautery makes early 
infiltration (such as preoperative or following induction) sensible. 
It is likely that by the time the patient is ready for surgical 
dissection, the effects of the INTRAPEC technique will have 
peaked. In addition, the safety of ultrasound guidance for vessel 
identification and needle guidance accuracy will be lost with a 
direct vision technique.
A postoperative injection using the same technique could be 
suggested as well. However, preoperative placement without 
an implant yields natural muscular architecture, making the 
sonographic landscape easier to navigate. The incidental 
placement or trapping of air anywhere in the surgical field would 
have deleterious effects on the acquisition of ultrasound imaging. 
Last, a fresh implant and carefully closed plastic surgery incision 
should be cautiously negotiated with further blocks. Accidental 
opening of these incisions for the plastics patient can lead to 
further closure revision, undesirable scar formation, infection, 
implant violation, or other avoidable complications. This can 

be avoided by simply placing the INTRAPEC injection before 
incision and plane rearrangement.
CONCLUSIONS
The ultrasound-guided INTRAPEC injection appears to 
enhance surgical field compliance during breast implantation for 
reconstruction and augmentation. The technique suggests that 
injecting the muscle itself, at the anterior/inferior border near 
the aponeurosis, may lead to less spasm, incidental trauma and 
bleeding, and reduced muscle confrontation to the surgeon. The 
placement of the injection is relatively simple and straightforward 
and can easily be accomplished in conjunction with a PECS 1 
block. The technique is further made safer by the addition of 
ultrasound guidance. This seems evident by not only improved 
accuracy from an in-plane needle guidance, but avoidance of 
significant structures, arguably only centimeters away from the 
target zone. Further safety is offered during the placement by 
the advantage of color Doppler viewing to assist in identification 
of vasculature in the infiltration zone. We look forward to and 
recognize the need for more formalized studies investigating this 
simple technique of surgical field improvement and potential pain 
reduction for surgical patients undergoing breast expansion or 
augmentation. By its very nature of being both a novel technique 
and a single case study, we recognize that although successfully 
demonstrating proof of concept, this technique is in its infancy, 
and clearly more studies are required to validate its use.

Anesthesia eJournal                         www.anesthesiaejournal.com
Volume 6 - No.  2018 Page 21

REFERENCES
1. O’Donnell CJ. Pectoral muscle spasms after mastectomy successfully treated with botulinum toxin injections. PM R. 2011 

Aug;3(8):781-2. doi: 10.1016/j.pmrj.2011.02.023
2. Govshievich A, Kirkham K, Brull R, Brown MH. Novel approach to intractable pectoralis major muscle spasms following 

submuscular expander-implant breast reconstruction. Plast Surg Case Studies. 2015;1(3):68-70.
3. Shin HJ, Shin JC, Kim WS, Chang WH, Lee SC. Application of ultrasound-guided trigger point injection for myofascial 

trigger points in the subscapularis and pectoralis muscles to post-mastectomy patients: a pilot study. Yonsei Med J. 
2014;55(3):792-799. https://doi.org/10.3349/ymj.2014.55.3.792

4. Leiman D, Barlow M, Carpin K, Piña EM, Casso D. Medial and lateral pectoral nerve block with liposomal bupivacaine 
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2014;2(12):e282. https://doi.org/10.1097/GOX.0000000000000253

5. Trignano E, Dessy LA, Fallico N, et al. Treatment of pectoralis major flap myospasms with botulinum toxin type A in head and 
neck reconstruction. J Plast Reconstr Aesthet Surg. 2012;65(2):e23-e28. https://doi.org/10.1016/j.bjps.2011.10.002

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