A PERIPFERAL NERVE STIMULATOR GUIDED POPLITEAL SCIATIC NERVE BLOCK COMBINED WITH ADDUCTOR CANAL BLOCK IN LOWER LEG SURGERY-AS A SOLE ANESTHETIC TECHNIQUE

The study will be a typeof prospective randomised controlled trial undertaken in adult patients of 18to 70 year of age admitted in SSG hospital requiring lower leg surgery with asample size of 60 patients.

Pre-operativePreparation:

•Patient to be kept nil by mouth(NBM) for minimum 6-8 Hours.

•Patient will be explained about VAS score preoperatively.

•Operation theatre preparation for all necessary equipments and drugs to be keptready.

•Anesthesia machine with monitor to be kept ready.

•IV line will be taken with 18G cannula.

Premedication**:-**

ON THE DAY BEFORESURGERY

Tab Ranitidine 150 mg PO 1 HS

ON THE DAY OF SURGERY

5 Minutes before induction:

Inj.Glycopyrrolate 0.2 mg IV

Inj.Ondansetron 4 mg IV

Anesthesiamethod:

INDUCTIONOF ANAESTHESIA:

Thepatients will be randomly allocated into two groups by sealed envelope method.

Groupingof Patients:

•Group P(N=30)

Patientswill be given Popliteal Sciatic Block  +Adductor Canal Block (Drug to be used:- 0.5% Bupivacaine  20 ml + 2% Lignocaine 20ml with 5mcg/ml1:200000 Adrenaline and Sodabicarbonate 2ml)

•Group S(N=30)

Patientswill be given Unilateral Spinal Anesthesia with Inj. Bupivacaine Heavy 0.5%1ml.

Ø  Injection Midazolam 1mg/kgwill be given inall the patients after procedure.

 TechniqueFor Popliteal Sciatic Block:-

Position:Supine with Hip Flexed at 30* by putting pillow below the heel and Knee FullyExtended.

Thelandmark for needle insertion is approximately 10cm above the Most Prominentpart of Lateral Femoral Condyle in the groove between Biceps Femoris  and the vastus Lateralis muscle.

 NerveLocator Technique: In proposed study we will use this technique.

•A22-gauge 8-inch insulated needle is attached to the negative electrode of thePNS. The extension tubing is primed and attached to a syringe filled with localanesthetic solution.

•Theinitial current strength is set at 3mA with 2Hz frequency and 0.1ms duration.

•The needle is inserted in the groove between the Biceps Femoris and Vastuslateralis by palpating it with finger tips and is directed perpendicular to theskin till the Planter Flexion of Foot is elicited.

•Amplitude to be decreased up to 0.5 mA while seeking maximal Planter Flexioncontraction. If necessary needle should be relocated to achieve adequatecontraction while reducing amplitude. If there is continued Planter Flexioncontraction when at 0.2 mA or less withdraw needle. Stimulation at this lowlevel may indicate intraneural placement of the needle.

•After the injection of 1 ml of local anesthetic the contractions should startto fade.

•Always aspiration should be done before injection, during injection and afterinjection to ensure that inadvertent intravascular injection has not occurred.If the aspiration for blood is negative, 21ml local anesthetic is injected.

•If the patient experiences excruciating pain or parasthesia with injectionwithdraw the needle slightly.

•Complete effect of the block will be achieved in 20 minutes.

TechniqueFor Adductor Canal Block

Position:Supine. A pillow will be placed under the knee and thigh.

Thelandmark for needle insertion is approximately 4 finger breadth (7 -8 cm) abovethe adductor tubercle on the medical condyle of the femur in the groove betweenSartorius and the vastus medialis muscle

Thegroove is also known as the Jobert’s fossa.

 NerveLocator Technique: In proposed study we will use this technique.

•A22-gauge 8-inch insulated needle is attached to the negative electrode of thePNS. The extension tubing is primed and attached to a syringe filled with LAsolution.

•Theinitial current strength is set at 3mA with 2Hz frequency and 0.1ms duration.

•Theblock is best done by standing on the opposite side to the block site.

•The needle is inserted in the groove between the vastus medialis and Sartoriusby palpating it with finger tips and is directed perpendicular to the skin withslight posterior angulation till the contraction of vastus medialis muscle iselicited.

•Amplitude to be decreased up to 0.5 mA while seeking maximal vastus medialiscontraction. If contractions are fading while reducing amplitude, needle shouldbe relocated to achieve adequate contraction. If there is continued vastus medialis contraction when at 0.2 mA or lesswithdraw needle. Stimulation at this low level may indicate intraneuralplacement of the needle.

•After the injection of 1 ml of local anesthetic the contractions should startto fade.

•Always aspiration should be done before injection, during injection and afterinjection to ensure that inadvertent intravascular injection has not occurred.If the aspiration for blood is negative, 21ml local anesthetic is injected.

•If the patient experiences excruciating pain or paresthesia with injectionwithdraw the needle slightly.

•Complete effect of the block will be achieved in 20 minutes.

 TechniqueFor Unilateral Spinal anesthesia

Position:Lateral (Operative site to be in lower side)

Under all aseptic and antisepticprecaution spinal anesthesia should be given in L3-L4 space with 23G spinalneedle with injection 0.5% Bupivacaine Heavy 1ml. Patient kept in lateralposition for 10 minutes.