Serratus plane block with sedation for patients submitted to axillary dissection: a prospective case series

ABSTRACT Axillary dissection is a standard surgical procedure for stage III skin and soft tissue tumors and is usually performed under general anesthesia. This study aimed to investigate the feasibility of performing axillary dissection with Serratus muscle plane block plus intravenous sedation. Fifteen patients undergoing axillary dissection were prospectively recruited. The patients were evaluated during their pre-operative anesthetic appointment, during their procedure, and at post-operative days 1 and 30. The blockade was performed superficial to the Serratus muscle at the level of fourth rib. Sedation was performed using propofol, fentanyl, dexmedetomidine, and S-ketamine. None of the patients required conversion to general anesthesia. Surgeons showed a highly positive response when asked about the anesthetic technique, and most of them found the technique “indistinguishable” from general anesthesia. The median (interquartile range) pain scores at rest over all time frames was 0 (0-0). Furthermore, no patients developed nausea, hemodynamic instability, or any complications associated with the technique. The Serratus plane block associated with intravenous sedation proved feasible for axillary lymphadenectomy, however, further clinical trials should evaluate potential advantages compared to other techniques.


Theobald
Serratus plane block with sedation for patients submitted to axillary dissection: a prospective case series tissue neoplasms who required axillary lymphadenectomy at the National Cancer Institute, Rio de Janeiro.We excluded patients with classification of the American Society of Anesthesiologists (ASA) greater than III, younger than 18 years old, weighing less than 40kg, or with ulceration, infection, or coagulopathy.Cases were non-consecutive due to logistical and human resource limitations stemming from the COVID-19 epidemic, which suspended recruitment for part of 2020.Recruitment began in September 2018 and ceased in February 2021.
Patients were evaluated at the outpatient preanesthetic evaluation visit, during the surgical procedure, on the first postoperative day (PO1), and after 30 days (PO30).The research team continued follow-up until PO30.
After standard monitoring, obtaining a peripheral venous line, and initial sedation, SPB was performed between the latissimus dorsi and serratus anterior muscles (superficial approach) at the level of the fourth rib, in the supine position or in lateral decubitus in the operating room.All SPB were performed by the same two anesthesiologists, experienced in regional anesthesia.This reduced the risk of inconsistency between cases.The initial volume was 40ml of a solution of 0.5% ropivacaine, 1% lidocaine, and epinephrine (1:200,000).Five minutes after the block, the research team performed an ultrasound evaluation of the axilla to explore the local anesthetic spread and classified it as poor, fair, good or excellent.
Surgeon and patient satisfaction were also assessed.Immediately after surgery, the primary surgeons rated their satisfaction with the anesthetic technique using a Likert scale such as "extremely satisfied", "satisfied", "neither satisfied nor dissatisfied", "dissatisfied", and "extremely dissatisfied".They also compared the technique to general anesthesia.On PO1, we also measured patient satisfaction with the anesthetic

RESULTS
We recruited 15 patients, whose baseline characteristics are available in Table 1.Nine patients   The primary surgeon rated the anesthesia on the Likert scale as "satisfied" or "extremely satisfied" on 14 occasions, and "neither satisfied nor dissatisfied", once.The technique used was classified by surgeons, when compared with general anesthesia, as "indistinguishable from general anesthesia" in 10 cases and "slightly challenging/adequate" in five occasions.
On PO1, six patients classified themselves as "satisfied" and nine as "extremely satisfied".Satisfaction scores are listed in Figure 1.Serratus plane block with sedation for patients submitted to axillary dissection: a prospective case series fifth ribs for the resection of a giant axillary lipoma 8 .SPB with 25ml of 0.75% ropivacaine has also been effectively used for lumpectomy and axillary lymphadenectomy 9 .
Jajur described a modified SPB between the second and third ribs in the midaxillary line with 10ml of 0.75% ropivacaine associated with adrenaline as effective for a patient undergoing axillary dissection 10 .In another case report, hypnosis and remifentanil techniques were combined with SPB superficial to the serratus anterior muscle to perform a lateral lumpectomy and axillary dissection 11 .Oliveira et al. described the use of SPB and supraclavicular brachial plexus block combined with sedation with dexmedetomidine and ketamine for a patient undergoing debridement of axillary necrotizing fasciitis 12 .Thus, to the best of our knowledge, we describe the first prospective series assessing the feasibility of this technique for patients undergoing axillary dissection.
Based on a cohort study that evaluated data from 2,526 patients who underwent axillary dissection due to stage III cutaneous melanoma, the identification of 10 to 15 lymph nodes in the surgical specimen is consistent with a procedure of adequate quality 13 The number of lymph nodes obtained in the surgical procedure in the studied sample, the high levels of surgeons' satisfaction, and the comparability of surgical field conditions with general anesthesia denote the feasibility of performing this surgical procedure with this technique 1 .
The blockade was performed superficially to the serratus anterior muscle in the current series of cases, at the level of the fourth rib.The block thus performed dissects and occupies the axillary lymphadenectomy surgical field, especially facilitating the resection of Theobald Serratus plane block with sedation for patients submitted to axillary dissection: a prospective case series level I and II lymph nodes.En bloc resection of the surgical specimen and part of the local anesthetic could potentially reduce the duration of the blockade, but also the risk of toxicity.Axillary dispersion measured by anesthesiologists was evaluated as good or excellent (60%), in agreement with a cadaveric study of SPB with 40ml 14 , and can be improved with other techniques capable of more consistent axillary spread 15 .

CONCLUSION
The practice of axillary lymphadenectomy using SPB without the combination with general anesthesia has potential economic, organizational, and analgesic advantages to be confirmed in clinical trials.
technique using the same Likert scale, and the quality of recovery with the 40-item Quality of Recovery scale (QoR-40).Between the postoperative days 28 and 35, we reassessed the participants, with the application of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30), recording the presence of surgical wound infection, skin necrosis, seroma, lymphedema, lymphatic fistula, and date of drain removal.

(
60%) were classified as having good or excellent dispersion of the local anesthetic in the ultrasound evaluation.An additional 20ml solution of 1% lidocaine was administered at the discretion of the anesthesia team in five patients with fair or poor axillary local anesthetic distribution.All patients underwent the procedure under moderate to deep sedation with propofol, fentanyl, dexmedetomidine, and S-ketamine.Median operative time was 85 minutes, and no patient required conversion to general anesthesia or any airway device other than an oxygen mask.The median number of lymph nodes extracted was 16 (Interquartile range 12.5-17).

Figure 3 .
Figure 3. Cumulative distribution of pain scores on the 11-item numeric scale in 90° abduction.The x-axis corresponds to the numeric rating scale.The y-axis corresponds to the inverse cumulative distribution of pain scores.The horizontal lines illustrate the 10th, 25th, 50th (median), 75th, and 90th percentiles.Pain scores were recorded (A) upon admission to the Post-Anesthetic Care Unit, (B) 2 hours postoperatively, (C) 24 hours postoperatively, and (D) at the 30-day post-operative visit..

Table 1 -
Baseline clinical and demographic characteristics.
Data are presented as n (%), mean (standard deviation) and median [interquartile range].ASA: American Society of Anesthesiologists ; ECOG:Eastern Cooperative Oncology Group .a Data from 13 cases; b Staging was stratified by histological type and grouped according to the 8 th Edition of the American Joint Committee on Cancer Manual.
a Data from13cases available; Data are presented as n (%) and median [interquartile range]; OR: Operating Room; PACU: Post-Anesthetic Care Unit; USG: Ultrasound.
Preoperative and postoperative scores were presented as mean (SD), mean difference (95% CI) and paired t-test p-value; CI: Confidence Interval; EORTC QLQ-C30: European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 ; QoR-40: 40-item Quality of Recovery Score ; a QoR-40 was obtained from all 15 patients at the preoperative assessment and on the first postoperative day; b EORTC QLQ-C30was obtained from all 15 patients at the preoperative assessment and from 13 patients at the 30-day postoperative visit.Only 13 patients with 2 completed consultations were used for statistical analysis.