Evaluation of Ultrasound-guided Erector Spinae Plane Block for Postoperative Analgesia in Laparoscopic Sleeve Gastrectomy: A Prospective, Randomized, Controlled Clinical Trial
Condition: Pain, Postoperative
MeSH terms: Pain, Postoperative
Study type: Interventional

Summary: 
      This study will help us in understanding the role of erector spinae block (ESPB) for
      postoperative pain control in patients undergoing upper GI laparoscopy surgeries. The
      surgeries included in this group include laparoscopic cholecystectomy, laparoscopic
      gastrectomy, laparoscopic umblical or epigastric hernia repair. Patients aged between 18 and
      65 years, scheduled to undergo any upper GI laparoscopy surgeries with an ASA score of 1 or 2
      will be included in the study. This is a prospective randomised controlled trial which will
      compare two groups receiving either erector spinae block or no block for postoperative pain
      control after upper GI laparoscopy surgeries
    

Detailed description: 
      Research Proposal and significance Postoperative analgesia should include strategies to
      reduce side effects. Intravenous analgesics are generally considered to be adequate for pain
      management in upper GI laparoscopic surgeries. However opioids can lead to nausea, vomiting
      and itching while NSAIDs affect the gastric, hepatic and renal systems and wound healing.
      Reducing opioid requirements during the perioperative period is among the current goals of
      enhanced recovery programs. The objective is to reduce all potential opioid-related
      side-eﬀects. Therefore, multimodal analgesics including regional blocks decrease the use of
      other analgesics and therefore decrease side effects.

      Objective The aim of this study is to evaluate the eﬀect of Erector spinae block (ESPB) on
      postoperative pain in upper GI laparoscopy surgeries, which leads to both visceral and
      somatic pain.

      Research review In this study, the surgeries included in upper GI laparoscopic surgeries are
      laparoscopic cholecystectomy, laparoscopic gastrectomy, laparoscopic umblical or epigastric
      hernia repair.

      n upper GI laparoscopy surgeries, postoperative pain is caused by two reasons; one is somatic
      pain from the trocar entry incisions and additionally peritoneal distention and diaphragm
      irritation due to high intra-abdominal pressure and CO2 insufflations lead to visceral pain
      as well. Therefore, any analgesic protocol for these surgeries must be effective on both
      sources of pain.

      Regional block techniques studied and considered part of multimodal anesthesia include
      transversus abdominis plane block (TAP), oblique subcostal transversus abdominis plane block
      (OSTAP or STAP) and paravertebral block. Apart from paravertebral block, these techniques
      only effect somatic pain and can therefore be inadequate in some cases. Ultrasound Guided
      paravertebral block is an advanced regional anesthesia technique. When considering that the
      pleura forms one boundary of the paravertebral space, ESPB can be considered an easier
      technique to perform. It is also safer because the needle remains behind the transverse
      process. However, non-inferiority studies comparing ESPB and paravertebral block are
      required. Erector Spinae Plane Block (ESPB) - first recently described for the treatment of
      thoracic neuropathic pain, is a peri-paravertebral regional anesthesia technique that has
      since been reported as an effective technique for prevention of postoperative pain in various
      surgeries. In ESPB, local anesthetic is reported to be administered in to the interfascial
      plane between the transverse process of the vertebra and the erector spinae muscles,
      spreading to multiple paravertebral spaces. Case reports have reported that ESPB effects both
      the ventral and dorsal rami and leading to blockage of both visceral and somatic pain.
      Anatomical dissection indicates that the likely mechanism of action is diffusion of local
      anaesthetic anteriorly through the connective tissues and ligaments spanning the adjacent
      transverse processes and into the vicinity of the spinal nerve roots. This is consistent with
      other reports of successful analgesia following injection into a similar tissue plane in the
      thorax.

      Tulgara et al in their study has shown that ultrasound guided bilateral single shot ESPB
      performed before general anesthesia induction in LC patients signiﬁcantly lowered NRS at rest
      in the ﬁrst 3h and lead to less analgesia requirement in the ﬁrst 24h when compared to a
      control group.

      Methodology Patients aged between 18 and 65years, scheduled to undergo any upper GI
      laparoscopy surgeries with an ASA score of 1 or 2 will be included in the study. Written
      informed consent for general anesthesia and all procedures will be obtained from all
      patients. Patients who refused enrollment or later requested removal for the study, those who
      are unable to give informed consent and patients with either contraindications for regional
      anesthesia, known allergy to local anesthetics, bleeding diathesis, use of anticoagulants or
      corticosteroids, inability to operate patient controlled analgesia (PCA) system, psychiatric
      disorders or use of psychiatric medications and conversion to open laparotomy will not be
      included in the study.

      There will be two groups of patients: control group (Group A) and ESPB group (Group B). Upon
      ward admission, a random ID will assigned to each patient. Simple randomization in the
      operating room will performed using the closed envelope method to determine which group the
      patient would be included in.

      The random ID assigned to each patient will be used when collecting all patient data in the
      ward postoperatively. The anesthesiologist performing the simple randomization will also
      perform the block but will not play any role in the collection of postoperative data or its
      analysis.

      General anesthesia and surgical technique will be the same for both groups. Standard
      monitoring procedures included pulse oximetry, electrocardiography, and noninvasive arterial
      pressure will be performed prior to anesthesia. Baseline heart rates, systolic and diastolic
      blood pressures, and mean arterial pressures will be recorded before anesthesia. Induction
      will performed using propofol 2-3 mgkg-1, fentanyl 100μg and Cisatracurium 0.2 mgkg-1.
      0.8-1.0 MAC sevoﬂurane and 0.05-0.1 μg/kg/min remifentanil infusion will be used for
      anesthesia maintenance. Remifentanil dosage will be adjusted according to hemodynamic
      parameters, up to 2 μg/kg/min. Standard perioperative intravenous analgesia protocol will
      include paracetamol 1g and Lornoxicam 16 mg.After completion of surgery, patients will be
      extubated once TOF ratio of >0.9 is acheived and transferred to the recovery room. Local
      anesthesia will not be applied to wounds. Pneumoperitoneum will be evacuated in all patients
      at the end of surgery. All patients will receive 8 mg Dexamethasone and 1 mg Granisteron as
      antiemtics.

      All blocks will be performed in lateral position after general anesthesia induction. ESPB
      will be performed under ultrasonographic guidance using a linear 6- to 10-MHz ultrasound
      probe. The linear ultrasound transducer will be placed in a longitudinal parasagittal
      orientation 3cm lateral to the T9 spinous process. The erector spinae muscles will be
      identiﬁed superﬁcial to the tip of the T9 transverse process. A 21-gauge 10-cm needle will be
      inserted using an in-plane superior-to-inferior approach or an outplane approach. The tip of
      the needle will be placed into the fascial plane on the deep (anterior) aspect of erector
      spinae muscle. The location of the needle tip will conﬁrmed by visible ﬂuid spread lifting
      erector spinae muscle oﬀ the bony shadow of the transverse process on ultrasonographic
      imaging. A total of 10-15 mL of 0.2% ropivacaine will be injected each side.

      The Numeric Rating Scale (NRS) will be used to evaluate postoperative pain. The NRS is a
      segmented numeric version of the visual analog scale (VAS) in which a respondent selects a
      whole number (0-10 integers) that best reﬂects the intensity of his/her pain. It is
      considered a one dimensional measure of pain intensity in adults. The 11-point numeric scale
      ranges from '0' representing one pain extreme ("no pain") to'10' representing the other pain
      extreme ("pain as bad as you can imagine" or "worst pain imaginable"). Changes in NRS at rest
      and on movement will be recorded at intervals.

      All patients will be followed using a standardized postoperative analgesia protocol which
      includes Morphine PCA. Morphine at a concentration of 1mg/ml is included in our PCA protocol
      (total volume 100mL.) PCAs will be set as no basal infusion and 1 mg bolus doses with a 10
      min lock out time. PCA will be commenced when the patient arrives in the recovery room. For
      rescue analgesia during the ﬁrst hour in the recovery room, 2 mg Morphine will be used if
      NRS≥4/10. The dosage will be repeated every 20 min if NRS > 4/10. Paracetamol 1g / 8h will be
      used during ward follow-up. If NRS < 2 and the patient refuses pain medication, this dosage
      will be skipped. As rescue analgesia in case of the pain score≥4/10 on NRS during 1-24h,
      Lornoxicam 16 mg IV will be performed. If the pain remains at same level in following 1h
      period Morphine 2 mg IV will be added. Patient will receive 1 mg Granisetron IV if complains
      of nausea/vomiting.

      Primary outcome measures at commencement of the study will be NRS pain score at 18th hours
      postoperatively both at rest and when coughing. Secondary outcome measures will be routine
      (paracetamol or morphine PCA) or rescue analgesic use within the ﬁrst 24h. In addition to the
      above measures, NRS pain scores will measured at other time intervals like 30 minutes, 1
      hour, 2 hours, 6 hours, 12 hours and 24 hours postoperatively. Also, shoulder pain during the
      ﬁrst 24 h and presence of postoperative nausea and vomiting will be noted. The severity of
      both nausea and sedation will be assessed by patients on a 4 point scale (none, mild,
      moderate, and severe). Nurses will note any vomiting in the recovery room or on the ward.
      Finally, the number of patients receiving Granisetron will be recorded.

      The null hypothesis of our study is that there is no diﬀerence in pain scores between ESPB
      and a control group receving standard analgesic regimen in patients undergoing upper GI
      laparoscopic surgeries.

      For sample size calculation, we used the study by Tulgara et al (16) done on laparoscopic
      cholecystectomy with pooled standard deviation of 0.725 and margin of error (d) as 0.6 units
      on NRS scale at α=0.05 and power 80 %.

      The sample size was calculated using the formula n = 2 ( Zα + Zβ) 2 X σ2/d2

      where Zα = 1.96 ( 95% confidence interval), Zβ = 0.84 ( 80% power), σ = 0.725, d = 0.6 Sample
      size calculated from this formula came out to be 22 in each group and with 10 %
      dropouts/attrition, it was 25 patients in each group.

      SPSS 16.0 Statistical package programme (SPSS, Chicago, IL, USA) will be used for statistical
      analysis. Descriptive statistics will be expressed as mean ± standard deviation. Univariate
      analysis compare in groups means using a 2-sample, independent t-test assuming equal
      variances for continuous variables. For data without normal distribution, Mann Whitney U test
      will be performed. Ratios will be compared using Chi-Square. Categorical variables will be
      compared using Fisher exact test. A p-value of<0.05 is considered statistically signiﬁcant.
      NRS will be analysed using repeated measures analysis.

      .
    

Intervention name(s): Erector spinae block
Intervention type(s): Procedure
Intervention description(s): Erector Spinae Plane Block (ESPB) - first recently described for the treatment of thoracic neuropathic pain, is a peri-paravertebral regional anesthesia technique that has since been reported as an effective technique for prevention of postoperative pain in various surgeries (10-12). In ESPB, local anesthetic is reported to be administered in to the interfascial plane between the transverse process of the vertebra and the erector spinae muscles, spreading to multiple paravertebral spaces.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomised controlled trial
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Erector spinae block; Upper GI laparoscopy; Pain