Laparoscopic cholecystectomy is   a   minimally invasive   procedure   that   causes moderate intensity of parietal, visceral, incisional and referred postoperative pain. A multimodal analgesic approach for management of such variety of pain is usually used for enhanced recovery of the patient. As a part of this approach, TAP block is a famous modality for postoperative analgesia in laparoscopic abdominal surgeries, which was first reported by Rafi. It is an abdominal field   block that   acts   on   the   myocutaneous nerve   supply   of   anterior    abdominal    compartment,    targeting    parietal    and incisional components of pain. The anatomical compartment between the transversus abdominis muscle and abdominal oblique internus muscle was described as TAP in clinical practice. The bolus anesthetic injection into this neurovascular fascial plane provides the anesthesiologist to block the dermatomal afferents of T7-11 intercostal nerves, T12 subcostal nerve, ilioinguinal and iliohypogastric nerves, and cutaneous branches of L1-3 nerves. The inferior lumbar triangle (triangle of Petit) which is an upright triangle and contains three major layers from superficial to deep: Subcutaneous fatty tissue, the abdominis obliquus internus muscle and transversus abdominis muscle and their fascias, is located among the anterior margin of the latissimus dorsi muscle, posterior margin of the abdominis obliquus externus muscle and inferiorly the crista iliaca. Its apex is the major anatomic landmark of the insertion. This triangular region is also known as a weak area in the posterior abdominal wall. The most common approach of performing TAP block with ultrasound for laparoscopic cholecystectomy is the classical or posterior one, which provides analgesia between T7 to the level of T10 dermatome. The rationale for performing subcostal TAP block (described by Hebbard) is to achieve the extent of the block up to the T6 dermatome, where the epigastric port of laparoscope is inserted for which the block is required to be given at a more anterior level. In this study, we attempt to compare the efficacy of right sided subcostal TAP block along with port site infiltration of local anaesthetic, with that of port site local anaesthetic infiltration alone in providing adequate post operative analgesia.

STUDY JUSTIFICATION

This study was designed to compare the efficacy of subcostal TAP block administered by the surgeon under laparoscopy guidance along with port site local anaesthetic infiltration, with that of port site infiltration alone, in providing adequate post operative analgesia. If TAP block can be made a routine, it will be possible to save hospital resources, reduce hospital stay, as well as patient expenditure.

AIMS AND OBJECTIVES:

To compare the efficacy of pre emptive laparoscopy guided subcostal TAP block along with port site inflitration, with that of port site infiltration alone in terms of:

 

1.      Levels of post-operative pain, monitored and recorded as per VAS scoring system

2.      Incidence of breakthrough pain

3.      Duration of post-operative hospital stay

REVIEW OF LITERATURE

It is well-known that less post-operative pain and rapid improvement in physical activity are the most important advantages of minimally invasive surgery[1]. Nevertheless, many patients suffer from significant pain after laparoscopic abdominal surgeries[2,3] including laparoscopic cholecystectomy. For pain control after open or laparoscopic abdominal surgery, different local methods of anesthesia have been described. So far, transversus abdominis plane (TAP) block technique which was first reported by Rafi [4], seems to offer an effective local pain control to the patients. Owen et al. [5] first described the open surgical approach for TAP block. A few years later, in 2011, pure laparoscopic TAP block was reported as a new technique [6]. Both techniques allow surgeons to apply TAP block under direct vision prior to the surgery. The anatomical compartment between the transversus abdominis muscle and internal oblique muscle was described as TAP in clinical practice [3,7]. The bolus anesthetic injection into this neurovascular fascial plane provides block to the dermatomal afferents of T7-11 intercostal nerves, T12 subcostal nerve, ilioinguinal and iliohypogastric nerves, and cutaneous branches of L1-3 nerves [8,9]. It is also known that the anatomical variations of the nerve entries and exits of the TAP are common. The inferior lumbar triangle (triangle of Petit) which is an upright triangle, contains three major layers from superficial to deep: Subcutaneous fatty tissue, the abdominis obliquus internus muscle and transversus abdominis muscle and their fascias, and is located among the anterior margin

of the latissimus dorsi muscle, posterior margin of the external oblique muscle and inferiorly the iliac crest. Its apex is the major anatomic landmark of the insertion [8]. This triangular region is also known as a weak area in the posterior abdominal wall. The apex of the triangle of Petit has been described as the “blind” insertion point of the needle. On the other hand, recent studies propose the use of an ultrasound probe for needle placement because of the potential risk for damage to adjacent structures. Magee et al.[6] performed TAP block under direct laparoscopic vision prior to laparoscopic surgical intervention and suggested the approach as an alternative method to avoid iatrogenic injuries.

The conventional method of giving a TAP block is the posterior TAP block. However, there have been reports that the posterior TAP block mainly provides analgesia below the T10 dermatomal level, and is thus more suitable for abdominal incisions below the umbilicus.

Hebbard [10] described a new technique called the subcostal TAP block, which involves depositing local anesthetic in a more cephalad position, immediately inferior to the costal margin on the anterior abdominal wall. The drug is injected at this location, immediately lateral to the linea semilunaris in the TAP. Subcostal TAP blocks are thought to be more effective in providing analgesia for incisions in the supra-umbilical region [10].

In the study, we aim to demonstrate the effectiveness of pre emptive laparoscopy assisted subcostal transversus abdominis plane block along with port site infiltration of local anaesthetic in providing post operative analgesia following laparoscopic cholecystectomy

HYPOTHESIS

Pre emptive combined TAP block + port site local anaesthetic infiltration provides better post operative analgesia, compared to port site infiltration alone, in laparoscopic cholecystectomy.

 

 

MATERIALS & METHODS

 

TYPE OF STUDY: Prospective Study

STUDY DESIGN: Randomized controlled trial (Single blinded)

PLACE OF STUDY:

SRM MEDICAL COLLEGE HOSPITAL AND RESEARCH CENTRE

 

PERIOD OF STUDY: 6 MONTHS (Aug 2020-Jan 2021)

 

STUDY POPULATION:

 

All patients admitted with the clinical diagnosis of cholelithiasis under General Surgery care in SRM MEDICAL COLLEGE HOSPITAL AND RESEARCH CENTRE would be taken as

Subjects for this study.

SAMPLE SIZE: All patients attending General Surgery OPD in the study period for cholelithiasis shall be encouraged to participate in the study

Group A: patients shall receive pre emptive subcostal TAP block with port site infiltration Group B: patients shall receive port site infiltration alone

Sample size was calculated using the following formula

k=n2/n1=1

                           Δ²

n1= (1.4²+1.4²/1) (1.96+0.84)²

                         1.46² n1=15 n2=K∗n1=15 

INCLUSION CRITERIA

●       All patients with cholelithiasis admitted under the General Surgery department in SRM Medical College Hospital and Research Centre fulfilling the following criteria:

1.      ASA I, II 2. Age-18-80

3. Consent to participate in the study

EXCLUSION CRITERIA:

●       Patients allergic to the local anaesthetic

●       Patients with previous history of coagulopathies/ cardiac diseases

●       Patients with skin diseases of anterior abdominal wall

●       Patients undergoing emergency surgery

●       Patients contraindicated for General Anaesthesia

●       Patients cleared for anaesthesia under ASA III/IV

●       Patients who underwent previous abdominal surgeries

●       Patients unwilling to participate in stud

METHODOLOGY:

➢   Patients attending General Surgery OPD will be included in the study based on the inclusion and exclusion criteria.

➢   Informed and written consent will be obtained regarding participation and the patients would be included in the study

Ø  The subjects would then be assigned to group A or group B in a randomized manner. The study subjects would then be matched with subjects undergoing similar procedure from the other group for analysis.

➢   A detailed history: presenting complaints, history of presenting illness, past history, history of any treatment undertaken, personal history shall be obtained, and a detailed clinical examination undertaken.

➢   Baseline investigations: Heamatological (Complete blood count with coagulation profile), biochemical (Liver function tests, renal function tests, serum electrolytes), serology, blood grouping typing will be carried out.

➢   USG/CT Abdomen/ MRCP shall be done to confirm diagnosis

➢   Cardiac assessment, anaesthetic fitness shall be obtained and then patient will be posted for the assigned procedure.

➢   Pre operatively, possible complications including infection, bleeding,bile leak, conversion to open surgery, shall be explained to the patient and informed, written consent obtained.

➢   0.1ml intradermal test dose of the anaesthetic is given pre operatively

➢   0.5ml/kg 0.5% Ropivacaine is mixed with 10ml distilled water

➢   After induction of general anesthesia, in both groups, 5ml of the diluted anaesthetic is infiltrated into the umbilical port site just before making the skin incision

➢   After insertion of this 10mm port, a pneumoperitoneum is created with pressure standardized to 12-15 mmHg for all patients.

➢   The laparoscope is inserted and general abdominal exploration is done.

➢   For the patients in Group A, a right sided subcostal injection is given using an 22-gauge spinal needle in the mid clavicular line.

➢   Subsequent to the perpendicular insertion, localization of the needle is detected under direct laparoscopic vision, and when the needle’s tip is positioned at the fascial space between the internal oblique and the transversus abdominis muscle, 30 cc of diluted ropivacaine is injected.

➢   Infiltration into the correct plane is confirmed by visualizing the needle traversing the extraperitoneal space without penetration of the parietal peritoneum.

➢   The needle is then withdrawn 0.5 mm and infiltration commenced.

➢   Confirmation of the corrected plan is highlighted by the presence of Doyle’s bulge, which is covered by the fibers of the thin transversus abdominis muscle.

➢   In both Groups A and B, 10mm epigastric port and two 5mm working ports are inserted under vision after instilling 5ml each of diluted ropivacaine locally.

 

 

 

 

➢   Post operatively, VAS (Visual Analogue Score) will be assessed at 1st hour, 4th hour, 8th hour, 16th hour and 24 hours following surgery for patients in either group.

 

➢    The patient shall be monitored for incidence of breakthrough pain (significant pain requiring the administration of superadded parenteral/oral analgesics); and the dose of analgesic drug given shall be recorded