Ultrasound-guided Paravertebral Block Versus Mid-point Transverse Process Pleura Block in Mastectomy Surgery
Condition: Mastectomy; Lymphedema; Anesthesia, Local; Surgery
MeSH terms: Lymphedema
Study type: Interventional
Phase: Phase 4

Summary: 
      This study was performed to analyze the postoperative analgesic effects of the paravertebral
      block (PVB) and Mid-Point Transverse Process Pleura (MTP) block after a unilateral mastectomy
      surgery.

      This study included 64 women aged 18-65 years, American Society of Anesthesiologists score
      I-III, who were scheduled for unilateral simple mastectomy operation due to breast cancer.
      Patients were randomly assigned to Group 1 (Patients undergoing PVB) or Group 2 (Patients
      undergoing MTP block) for a ratio of 1:1, including 32 patients each, using a
      computer-generated table of random numbers and concealed sealed opaque envelopes.

      Patients were placed in the prone position. The linear ultrasound probe was fixed to the
      T3-T4 vertebra level. The skin and subcutaneous tissue were anaesthetized with 2% lidocaine,
      then 22 gauge 100 mm needle was led in a cranial-cephalic direction to the paravertebral gap.
      Trapezius, rhomboid, erector spinae muscles were crossed by seeing the tip of the needle.
      Transverse processes were reached and the intercostal muscles were passed. When the needle
      reached the paravertebral level in Group 1, and the midpoint level between the transverse
      process and pleura in Group 2, it was observed that there was no blood or air by aspiration.
      Then, the needle location was confirmed with 0.5-1 mL of saline, and a 20 mL of 0.25%
      bupivacaine was applied. Thirty minutes after block application, the sensorial block level
      was evaluated by pinprick test at the midclavicular line, and the blocked dermatome area was
      recorded as front and back. Complications developed during the process (such as hypotension,
      vascular injury, local anaesthetic toxicity) were recorded.Routine general anesthesia
      protocol was performed to all patients.At the end of the surgery, neuromuscular block
      antagonization was performed with 4 mg/kg sugammadex. All of the patients were extubated and
      taken to the postanesthetic care unit (PACU). In the PACU, a patient-controlled analgesia
      device (PCA) containing fentanyl was administered.

      Time to the first request for analgesia, postoperative fentanyl consumption, and VAS score
      values at rest and in motion at postoperative 1, 4, 8, 12, 16, 20 and 24 hours, the duration
      of block implementation and the duration of surgery were recorded.
    

Detailed description: 
      This prospective randomized controlled trial was performed to analyze the postoperative
      analgesic effects of the paravertebral block (PVB) and Mid-Point Transverse Process Pleura
      (MTP) block after a unilateral mastectomy surgery.

      This prospective randomized placebo-controlled triple-blind study was approved by the Ethical
      Committee of Ataturk University, Medical Faculty, Erzurum, Turkey. The study was carried out
      at the Anesthesiology and Reanimation Department of Ataturk University, Medical Faculty,
      Erzurum, Turkey.This study included 64 women aged 18-65 years, American Society of
      Anesthesiologists score I-III, who were scheduled for unilateral simple mastectomy operation
      due to breast cancer.The day before surgery, patients were assessed by a researcher who was
      blind to group assignment. All patients were informed about the study, and written informed
      consent was obtained from all participants who agreed to participate in the study.

      This study was planned as triple-blind; patients and investigators were blinded to the group
      allocation. The patients were fasted for 8 hours before surgery. Before the anesthesia
      procedure, demographic data of all patients (age, weight, height, ASA physical status),
      baseline values of heart rate, systolic, diastolic and average blood pressure were recorded.
      Vascular access was established for all patients via 22-gauge intravenous cannula, and
      premedication was provided using 0.03 mg/kg of IV midazolam. Patients were randomly assigned
      to Group 1 (Patients undergoing PVB) or Group 2 (Patients undergoing MTP block) for a ratio
      of 1:1, including 32 patients each, using a computer-generated table of random numbers and
      concealed sealed opaque envelopes. An investigator opened the sealed opaque envelopes before
      the block application. An another anesthetist who was blinded to the group assignment was
      responsible for collecting intra-and postoperative data. All surgeries were done by the same
      surgical and anaesthetic teams.

      All blocks were fulfilled by the same anesthesiologist, who had at least five years of
      experience in the profession, with the help of a flat probe (1-8 MHz) and using 22 gauge, 100
      mm insulated facet tip needles before general anesthesia. Patients were placed in a sitting
      position, spinous processes were marked starting from the C7 spinous process to the T6 level.
      Then, patients were placed in the prone position. After cleaning the area with antiseptic
      solution, the sterilized linear ultrasonography probe (Esaote MyLab30®, CA631 high-frequency
      probe, United Kingdom) was covered. The flat probe was placed between two transverse
      processes on the paramedian plane; transverse processes, superior costotransverse ligament
      and pleura were consecutively visualized. The linear ultrasound probe was fixed to the T3-T4
      vertebra level. The skin and subcutaneous tissue were anesthetized with 2% lidocaine, then 22
      gauge 100 mm needle (Stimuplex ®; B Braun, Melsungen, Germany) was led in a cranial-cephalic
      direction to the paravertebral gap. Trapezius, rhomboid, erector spinae muscles were crossed
      by seeing the tip of the needle. Transverse processes were reached and the intercostal
      muscles were passed. When the needle reached the paravertebral level in Group 1, and the
      midpoint level between the transverse process and pleura in Group 2, it was observed that
      there was no blood or air by aspiration. Then, the needle location was confirmed with 0.5-1
      mL of saline, and a 20 mL of 0.25% bupivacaine was applied. Local anesthetic dissemination
      was seen in both cranial and caudal directions. Thirty minutes after block application, the
      sensorial block level was evaluated by pinprick test (normal sensation:0, decreased
      sensation:1, insensitivity:2) at the midclavicular line, and the blocked dermatome area was
      recorded as front and back. The duration from placing the patient in the prone position to
      removing the needle used for the block procedure was defined as the block application
      duration and recorded. Complications developed during the process (such as hypotension,
      vascular injury, local anesthetic toxicity) were recorded.

      Routine general anesthesia protocol was performed using 2-3 mg/kg IV propofol, 2 µg/kg IV
      fentanyl and 0.6 mg/kg IV rocuronium. Anesthesia was maintained with desflurane, a fresh gas
      flow of 3 L/min and a nitrous oxide mixed with oxygen in a 2:1 ratio. During surgery, the
      patients' systolic, diastolic and average artery blood pressures and oxygen saturation values
      were recorded in the 5th, 10th, 15th, 20th, 35th, and 50th minutes, and postoperative 1st and
      2nd hours. All operations were performed by the same surgical team using the same surgical
      technique.

      At the end of the surgery, neuromuscular block antagonization was performed with 4 mg/kg
      sugammadex. All of the patients were extubated and taken to the postanesthetic care unit
      (PACU). Patients with a modified Aldrete score of 9 and above were transferred to the clinic.
      At the end of the surgery, IV 1g of paracetamol was administered to all patients. The same
      dose was repeated every 6 hours postoperatively. To prevent postoperative nausea and
      vomiting, IV 8 mg of ondansetron was administered to all patients. Intravenous ephedrine (6
      mg) was used to treat hypotension (a 20% decrease in systolic blood pressure compared to
      preoperative values) and IV atropine (1 mg) was given in case of bradycardia (the heart rate
      < 45 beats/minute) during surgery. When nausea and vomiting were observed, intravenous
      metoclopramide (10 mg) was administered.

      In the PACU, a patient-controlled analgesia device (PCA) containing fentanyl was
      administered. The PCA was set at a 10 μg/mL concentration, with a 50 μg loading dose, 10
      minutes lockout duration, a bolus of 25 μg, and without basal infusion, and it was left
      connected for 24 hours. Postoperative fentanyl consumption was recorded as 0-4 hours, 4-8
      hours, 8-12 hours, 12-16 hours, 16-20 hours, 20-24 hours and 24 hours total. A
      patient-controlled analgesia device (PCA), which contains fentanyl at a concentration of 10
      mcg/ml, with a loading dose of 50mcg, a lock-out duration of 10 minutes, a bolus dose of 25
      mcg, and no basal infusion, was connected to all patients in the PACU. Postoperative pain was
      assessed using Visual Analog Pain Scale (VAS), which ranged from 0 (no pain) to 10 (worst
      imaginable pain) in the postoperative 1, 4, 8, 12, 16, 20 and 24th hours. Patients with a VAS
      score of 4 and above received 25 mg of rescue meperidine. The incidence of nausea and
      vomiting was recorded in the postoperative first 24 hours. Postoperative follow-up of the
      cases was done by an independent observer who was blinded to the group assignment.

      Time to the first request for analgesia, postoperative fentanyl consumption, and VAS score
      values at rest and in motion at postoperative 1, 4, 8, 12, 16, 20 and 24 hours, the duration
      of block implementation and the duration of surgery were recorded.

      Power analysis for the study was calculated using the NCSS-PASS (NCSS LLC, Kaysville, Utah)
      software. The primary end point of the study was the total opioid consumption for the first
      24 hours postoperatively. The minimum sample size required for this study was calculated
      based on Gürkan et al.'s study. They reported that the difference between groups opioid
      requirements in the first 24 hours after surgery was 1.5; the common standard deviation
      within a group was assumed to be 3.43 and 4.15. As a result of a power analysis, the sample
      size for a group was determined to be 30 patients with a power of 80% and alpha of 5%. It was
      planned to include 64 patients throughout the study, 32 patients in each group, considering
      potential dropouts.

      The SPSS 20 package software was used for data analysis. Numerical data were expressed as
      mean and standard deviation, categorical data were presented as numbers (n) and percentages
      (%). The normal distribution of data were evaluated using a the Kolmogorov-Smirnov Z test.
      Independent sample t-test was used for the analysis of parametric data and Mann-Whitney U
      test was used for the analysis of non-parametric data. Analysis of repetitive measurements in
      intra-group comparisons was done with ANOVA, analysis of categorical data was done using
      chi-square test. The results were considered statistically significant if p value<0.05.
    

Intervention name(s): bupivacaine; 22 gauge 100 mm needle; Propofol; fentanyl
Intervention type(s): Drug; Device; Drug; Drug
Intervention description(s): Block applications; Block applications; Routine general anesthesia protocol; patient-controlled analgesia
Other intervention name(s): needle
Intervention MeSH terms: Fentanyl; Bupivacaine; Propofol
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Patients were randomly assigned to Group 1 (Patients undergoing PVB) or Group 2 (Patients undergoing MTP block) for a ratio of 1:1, including 32 patients each, using a computer-generated table of random numbers and concealed sealed opaque envelopes. An investigator opened the sealed opaque envelopes before the block application.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: mastectomy; anesthesia; paravertebral block; mid-Point Transverse Process Pleura block; patient-controlled analgesia