Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT06322316 |
| Other study ID # |
MS-492-2022 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
October 1, 2022 |
| Est. completion date |
April 1, 2023 |
Study information
| Verified date |
March 2024 |
| Source |
National Cancer Institute, Egypt |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Modified radical mastectomy (MRM) is the most commonly performed surgical procedure in breast
cancer patients and is usually associated with severe postoperative pain. The peripheral
nerve block techniques were suggested to reduce acuter post-mastectomy pain. The study
compared the analgesic efficacy of retrolaminar block (RLB) and ESPB in patients undergoing
MRM.
Description:
Introduction Globally, breast cancer remains the most prevalent cancer among females, with an
estimated incidence of 31% and mortality of 15%. Surgery is foremost in managing breast
cancer, where modified radical mastectomy (MRM) is the most commonly performed procedure.
This procedure implicates vigorous tissue dissection and seroma formation with many
postoperative complications. Pain is the main complaint following MRM, affecting up to 50% of
women, and 25-60% develop persistent chronic postmastectomy pain.
Therefore, adequate pain control is crucial to postoperative management after MRM. Numerous
analgesic methods were suggested to reduce acuter post-mastectomy pain. Opioid-related
adverse events include nausea and vomiting, respiratory depression, sedation, and dizziness.
Most mastectomy-related pain originates from the chest wall's sensory nerves. The peripheral
nerve block techniques have gained increased interest in treating postoperative pain. The
erector spinae plane block (ESPB) is one of these techniques that proved effective in various
surgical procedures, including breast surgery. It encompasses injecting the local anesthetic
(LA) solution deep into the erector spinae muscle (ESM), which eventually spreads through the
paravertebral space. Ultrasound-guided retrolaminar block (RLB) is another approach that was
found to be effective for pain relief after thoracic surgery. In RLB, LA is injected into the
space between the ESM and the lamina of the thoracic vertebra.
Both techniques are considered variants of paravertebral block; however, prospective studies
comparing RLB and ESPB are limited. Therefore, this study was designed to compare the
analgesic efficacy of ultrasound-guided retrolaminar block and erector spinae plane block in
patients undergoing modified radical mastectomy.
Patients and Methods:
This randomized single-blinded study was conducted at the National Cancer Institute (NCI),
Cairo University from October 2022 and finished March 2023. The study was approved by the
institutional review board and the scientific committee of the anesthesia department of the
NCI and Faculty of Medicine, Cairo University. All participants provided written informed
consent before enrollment in the study after fully explaining the procedures and possible
complications.
The study involved 60 female patients scheduled for MRM under general anesthesia with the
following inclusion criteria: age 18 to 65, ASA class II or III, and body mass index (BMI) of
20-35 kg/m2. Patients with known sensitivity or contraindication to the drugs used in the
study, history of psychological disorders or chronic pain syndromes, contraindication to
regional anesthesia (local sepsis, pre-existing peripheral neuropathies, coagulopathy),
severe respiratory or cardiac conditions, advanced liver or kidney disease were excluded from
the study.
The patients were randomly allocated into one of two equal groups using computer-generated
random numbers in opaque closed envelopes. An independent statistician performed the
randomization. The grouping was revealed only when the patient was transferred to the
pre-anesthetic room. The RLB Group (n=30) received a preoperative ultrasound-guided
retrolaminar block using 20 ml levobupivacaine 0.25%. The ESPB Group (n=30) received a
preoperative ultrasound-guided erector spinae plane block using 20 ml levobupivacaine 0.25%.
Preoperative assessment included thorough history taking, physical examination, and
laboratory and radiological investigations. The patients were instructed to report pain using
the Numeric Pain Rating Scale (NPRS), where 0 = no pain and 10 = worst imaginable pain. All
patients were premedicated with IV midazolam 0.01-0.02 mg/kg 30 minutes before surgery. In
both blocks, a Fujifilm Sonosite M-Turbo Ultrasound system linear probe was used (SN.04RQZ6)
. After performing blocks lung ultrasound was performed to exclude pneumothorax.
Retrolaminar Block Technique The block was performed under complete aseptic precautions. The
ultrasound probe was placed on the back in a transverse orientation on the lateral side of
the posterior median line to identify the lamina of the 5th vertebra, ESM, and
transversospinalis muscles of the target segment. A skin wheal using 3 ml of 1% lidocaine was
made 2-3 cm medial to the transducer. A 38-mm 22-gauge regional block needle was advanced
using an in-plane technique. When the puncture needle touched the lamina, with no blood, gas,
or cerebrospinal fluid observed on aspiration, 20 mL of 0.25% levobupivacaine was
administered between the transversospinalis muscle and lamina. The LA diffusion between the
lamina and the ESM indicated a successful puncture.
Erector spinae plane block:
The ultrasound probe was placed on the back in a transverse orientation to identify the tip
of the T5 transverse process as flat, squared-off acoustic shadows with a faint image of the
pleura visible. When the tip of the transverse process was centered on the ultrasound screen,
the probe was rotated to a longitudinal orientation. In the parasagittal view, the following
layers were visible superficial to the acoustic shadows of the transverse processes: skin and
subcutaneous tissue, trapezius, ESM, and T5 transverse process. A skin wheal was made using 3
ml of 1% lidocaine; then, the block needle was inserted in-plane in a cranial-to-caudal
direction until contact was made with the T5 transverse process. The correct location of the
needle tip in the fascial plane deep to the ESM was confirmed by injecting 0.5-1.0 ml of
normal saline and seeing the fluid lifting the ESM off the transverse process without
distending the muscle. After aspiration to avoid intravascular injection, 20 ml
levobupivacaine 0.25% was injected.
Anesthetic Management:
All patients were monitored continuously using electrocardiography, non-invasive blood
pressure, peripheral O2 saturation, temperature probe, and end-tidal CO2 throughout the
surgical procedure. Anesthesia was induced using fentanyl 2 μg/kg and propofol 2 mg/kg IV.
Tracheal intubation was facilitated using rocuronium 0.5 mg/kg IV. Anesthesia was maintained
with inhaled sevoflurane 2.0-2.5% in oxygen-enriched air (FiO2=0.5). Maintenance doses of
rocuronium 0.1 mg\kg were provided every 30 minutes. Paracetamol 500 mg and ketorolac 30 mg
were provided as a part of multimodal analgesia. Rescue analgesia of fentanyl 1 μg/kg was
given if the mean arterial blood pressure (MAP) or heart rate (HR) rose above 20% of baseline
levels. The patients were mechanically ventilated at appropriate settings to keep end-tidal
CO2 at 30-35 mmHg.
The first reading of MAP and HR was taken before induction of general anesthesia as a
baseline reading. Then, another reading was taken immediately before incision and at
30-minute intervals intraoperatively. Hypotension (reduction > 20% of baseline reading) was
treated with 0.9% normal saline and/or 5 mg ephedrine in incremental doses to maintain MAP
above 70 mmHg. The residual neuromuscular blockade was reversed using neostigmine 0.05 mg/kg
and atropine 0.02 mg/kg. Extubation was performed after complete recovery of the airway
reflexes.
Postoperatively the NPRS score, MAP, and HR were noted immediately on arrival and every 2
hours. Multimodal analgesia was provided as paracetamol 500 mg/6 hours and ketorolac 30 mg/8
hours IV. Rescue analgesia was provided as IV morphine 3 mg boluses when the patient
indicated an NPRS score ≥ 4. The total amount of morphine given in 24 hours was recorded, and
a maximum dose of 0.5 mg/kg/24 hours of morphine was allowed. Side effects such as nausea,
vomiting, sedation, hallucination, and respiratory depression (respiratory rate < 10/minute)
were recorded. Moderate or severe postoperative nausea and vomiting (PONV) was treated with
0.1 mg/kg of IV ondansetron.
