To Assess the Efficacy of Anterior Approach to Both Femoral and Sciatic Nerve Via a Single Skin Site Injection Technique Vs Classical Two Site Injection Technique using Nerve Locator for Lower Limb Surgery

Girish, B K (2013) To Assess the Efficacy of Anterior Approach to Both Femoral and Sciatic Nerve Via a Single Skin Site Injection Technique Vs Classical Two Site Injection Technique using Nerve Locator for Lower Limb Surgery. Masters thesis, Stanley Medical College, Chennai.


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INTRODUCTION: Peripheral nerve blocks have been increasingly recognized as the technique of choice for providing anaesthesia and postoperative analgesia. These techniques have evolved as the sole technique for surgery and are also used as a treatment modality in acute and chronic pain management. There technique avoids the complications of general anaesthesia, also where general anesthesia and other modes of anesthesia cannot be given. The peripheral nerve blockade provides better hemodynamic conditions and also provides good post-operative pain relief. When the sciatic nerve block is combined with femoral nerve block the entire lower extremity can be blocked providing surgical anesthesia and good post operative pain relief. Several techniques are known to block sciatic nerve. The blocks to the lower limb can be performed in different positions. The positions may be supine, lateral or prone. Lower extremity operations requires blockade of two nerves and since the change of the patient position will be difficult and painful in trauma or arthritis in old age, the method of block needs to consider the change of position of patient and joint mobility. For surgery below knee in trauma patients, who cannot change the position from supine to prone or lateral position, the anterior approach to both sciatic and femoral nerve is indicated. Anterior approach is easy to perform in supine position with minimal discomfort to patient especially in case of trauma, as no change of position is required. Single skin needle injection also causes minimal discomfort to patients. My study attempts to evaluate the techniques of combined femoral and sciatic nerve block through anterior approach by using peripheral nerve stimulator. AIM: To assess the efficacy of combined anterior Approach to both femoral and sciatic nerve via a single skin site injection technique vs. classical two site injection technique using nerve locator for lower limb surgery. MATERIALS AND METHODS: Study Design: This is a single blinded, prospective, randomized study. This study was done at Government Stanley medical college and hospital, Chennai during the period of November 2011 to May 2012. After obtaining clearance from the Institutional Ethical Committee of the Stanley Medical College, Chennai-1, a pilot study was done to calculate the sample size. A pilot study with a sample size of 5patients in each group was done before the start of the study to decide on sample size. The sample size calculated based on the formula given in monographers on statistics and applied probability. The 60 patients are divided into two groups as follows: Group ONE – single needle technique, Group TWO – Classical two needles technique. Inclusion criteria: 1. Age 20-60 Yrs, 2. Both sexes, 3. ASA I-II undergoing surgery for both elective/emergency below knee. Exclusion criteria: 1. Pregnancy, psychiatric illness, 2. Infection at the puncture site, 3. Allergy to amide local anesthetics. MATERIALS: The following materials were needed for the study: i. Injection 2% lignocaine – 20 ml. ii. Injection 0.5% bupivacaine – 20 ml. iii. Injection adrenaline used at dosage of 5 microgram / ml. iv. Distilled water-20 ml. v. Injection midazolam at dosage of 20 microgram / kg. vi. Injection fentanyl at dosage of 1 microgram / kg. vii. One 20ml syringe for administration of local anaesthetic mixture. viii. Sterile towels and 4*4 gauge packs. ix. Sterile gloves, Marking pens and Surface electrodes. x. One 25g needle for skin infiltration. xi. Nerve stimulator - Stimuplex DigRc-B.Braun. xii. Needle - 22 gauge, 5 cms -long and 15cms, short bevelled insulated needle (StimuplexDig, B.Braun). xiii. ASA Standard monitors – pulse oxymetry (SPO2), non invasive blood pressure (NIBP) and electrocardiogram (ECG). xiv. Appropriate size endotracheal tubes and laryngoscopes. xv. Intravenous fluids, intravenous cannula and emergency drugs. Statistical Tools: The information collected regarding all the selected cases were recorded in a master chart. The observations were compiled and data’s were expressed as mean± SD. Quantitative analysis was compared with independent sample student’s t test. Qualitative analysis was compared with chi-square test. When using these tests to compare mean among two groups, p-value of less than 0.05 was taken as significant. All analyses were done using SPSS version 11.5 statistical software. Group One - Single Needle Technique, Group Two- Two Needle Technique. The study was done with the patient’s age ranging from minimum of 20 years to maximum of 60 years. SUMMARY: This randomised prospective study was done on 120 patients satisfying the inclusion criteria and undergoing surgeries below knee surgery. They were assigned into two groups, Group ONE and Group TWO. Of which, 60 patients received newer single needle technique for combined femoral and sciatic nerve block through anterior approach using nerve locator in group ONE, and other 60 patients received classical two needle technique block for combined femoral and sciatic block through anterior approach using nerve locator in Group TWO. The complete sensory block at the end of 40 minutes was seen in 52 patients of Group ONE and 51 patients of Group TWO.8 patients in Group ONE and 9 patients in Group TWO were excluded from the study due to lack of complete sensory block at end of 40 minutes. Parameters observed were the performance time, onset of femoral sensory block, onset of sciatic sensory block, onset of motor block, duration of motor block, duration of post-op analgesia (duration of sensory block), and block related complications like haematoma formation , vessel puncture and nerve injury. The study shows that: 1. Procedure time was shorter in Group ONE compared to Group TWO. 2. Onset of femoral sensory block was earlier in Group TWO compared to Group ONE. 3. Onset of sciatic sensory block was earlier in Group ONE compared to Group TWO. 4. Even though the Onset of motor block was earlier in Group ONE compared to Group TWO, it was not statistically significant. 5. Degree of motor blockade was similar in both groups. 6. Duration of motor block was longer in Group ONE compared to Group TWO. 7. Duration of post – operative analgesia was longer in Group ONE compared to Group TWO. 8. Complications- there were no significant complications like accidental vascular puncture, anaphylaxis or toxicity. CONCLUSION: In my study, it is found that the newer anterior approach using single skin needle technique for performing sciatic and femoral nerve blocks is easy and reliable. It is an alternative to subarachnoid block for below knee surgeries, especially in patients with trauma and in patients with reduced cardio pulmonary reserve. It has the advantage of short procedure time, prolonged sensory and motor blockade with good post operative pain relief compared to classic two needle technique.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Anterior Approach ; Femoral ; Sciatic Nerve ; Single Skin Site Injection Technique ; Classical Two Site Injection Technique ; Nerve Locator ; Lower Limb Surgery.
Subjects: MEDICAL > Anaesthesiology
Depositing User: Subramani R
Date Deposited: 22 Apr 2018 16:41
Last Modified: 28 Apr 2018 17:59

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