Axonal Injury with Persistent Neuropathy following Popliteal Nerve Block for Cheilectomy Surgery

Peripheral nerve blocks are often used for foot and ankle surgery. The occurrence of persistent neurological symptoms thereafter is very rare. Preventive strategies pose no guarantee and uncovering true etiology is often complicated. We discuss a case in which a young, healthy patient developed nerve damage after an uneventful popliteal block and cheilectomy. Nerve conduction studies revealed axonal injury in the distribution area of the sciatic nerve. The neurological symptoms persisted for more than 12 months, emotionally affecting the patient greatly. Patients will primarily report to the orthopedic surgeon, for whom cooperation with anaesthesia and neurology is of importance. Anesthetic involvement probably improves patient satisfaction during complication management.

Regional anesthesia for compartment syndrome as a complication of ECMO. Case report

We present the case of a patient intervened for mechanical mitral replacement, tricuspid annuloplasty, and correction of a total anomalous pulmonary venous return, which required Extracorporeal Membrane Oxygenation (ECMO) in the immediate postoperative period because of refractory cardiogenic shock. After withdrawal of the arterial cannula, the patient developed compartment syndrome of the right lower limb, requiring urgent intervention. Also, the patient went into respiratory failure, requiring support with high flow oxygen cannula. Given the patient’s condition, general anesthesia was discarded. An ultrasound-guided popliteal block and sedation with dexmedetomidine and ketamine was performed instead, maintaining the high flow nasal cannula. Regional anesthesia along with dexmedetomidine and ketamine could be an alternative for a surgical procedure in patients with high risk of cardiovascular and respiratory complications.

Comparison of the Combined Femoral and Lateral Femoral Cutaneous Nerve Block Plus Popliteal Block with Spinal Anesthesia for Thigh Tourniquet Pain During Foot or Ankle Surgery: A Randomized Clinical Trial

Background: A pneumatic thigh tourniquet is routinely used during lower-extremity orthopedic surgeries to provide a bloodless field. When using peripheral nerve blocks, tourniquet-related thigh pain and discomfort limit their routine use as an anesthetic method. Objectives: The aim of the present prospective, randomized study was to compare the efficacy of combined femoral nerve/lateral femoral cutaneous nerve block technique and spinal anesthesia on intraoperative thigh tourniquet pain. Methods: We studied 60 American Society of Anesthesiologists physical status I-II patients scheduled for orthopedic surgery on the foot or ankle using a pneumatic thigh tourniquet. They were randomly divided into two equal groups. The peripheral nerve block group received a combined popliteal, femoral, and lateral femoral cutaneous nerve block under ultrasound-guidance. In both groups, the level of sensory blockade was determined by the pinprick test. The block performance time, anesthetic effect time, intraoperative tourniquet pain scores, the amount of fentanyl and ketamine, surgery duration, and patient’s satisfaction were recorded. Results: The patients’ characteristics were comparable in the two groups. The mean duration of block performance and anesthetic effect, intraoperative tourniquet pain scores, and the amount of intravenous analgesics in the peripheral nerve block group were significantly greater than those in the spinal anesthesia group. Patient satisfaction was similar in both groups. Conclusions: Spinal anesthesia is significantly more effective than the peripheral nerve block method in reducing thigh tourniquet pain. A combined femoral and lateral femoral cutaneous nerve block with popliteal block can improve thigh tourniquet tolerance if supplemented with intravenous analgesics.

Composite Anatomical Variations between the Sciatic Nerve and the Piriformis Muscle: A Nepalese Cadaveric Study

Piriformis syndrome is a rare syndrome which is one of the main causes of nondiscogenic sciatica causing severe low back pain due to entrapment of sciatic nerve either by the hypertrophy or by inflammation of the piriformis muscle. We have carried out dissection in 20 Nepalese cadavers. Out of 40 dissected gluteal regions, 37 exhibited typical appearance of sciatic nerve, piriformis muscle, and their relations resembling type-a, whereas 3 gluteal regions showed composite structural variations resembling type-b and type-c based on Beaton and Anson’s classification. Knowledge pertaining to such variations will be helpful during a surgical intervention in the gluteal region and in turn reduces the risk of injuring these nerves which are more susceptible to damage. Our study reports such variations in Nepalese population which will be helpful during evaluation of the pain induction in various test positions and also useful for analysis of the range of the neurological deficiency in sciatic nerve neuropathies. The present study also explains the basis of the unsuccessful attempt of the sciatic nerve block during popliteal block anaesthesia.

SONOGRAPHIC EVALUATION O F SCIATIC NERVE ANATOMY AND SUBCUTANEOUS DEPTH AT ITS TERMINATION IN POSTERIOR THIGH: IMPORTANCE IN POPLITEAL BLOCKS

Introduction: Sciatic nerve (SN) is about 2cm wide, forms in the pelvis from ventral rami of L4-S3 spinal nerves and leaves the pelvis by passing out via greater sciatic foramen inferior to piriformis. It travels in the posterior compartment of thigh where it is crossed by long head of biceps femoris, and terminates by dividing into tibial and common peroneal nerves proximal to knee near the apex of popliteal fossa. Cross sectional area (CSA) of SN at mid-thigh and the level of termination may vary. This is important in respect to clinical as well as treatment purpose for the performance of popliteal block. Popliteal nerve block is the block of SN in the popliteal fossa, it is ideal for surgeries of lower leg, particularly below the knee, foot and ankle. It anesthetizes the same dermatomes as both the anterior and lateral approaches to the SN. Variability in level of termination and subcutaneous depth may account for the frequent failures associated with popliteal block. Ultrasound guided sciatic nerve blockade when performed in a systematic manner, is associated with a high success rate. Aims & Objectives: Present study was done to evaluate sciatic nerve morphometry and its depth from skin with the help of high resolution ultrasonography (HRUS) and highlight importance of relevant anatomy in relation to popliteal nerve block. Material & Methods: Study was conducted in the Department of Anatomy, King George's Medical University, Lucknow, Uttar Pradesh, India in 50 volunteer students of 1st year MBBS 2018 batch (25 males & 25 females). Sonography was done with the help of Esaote Europe My Lab 40 ultrasound machine (installed in the Department of Anatomy, KGMU) to observe Cross sectional area, perimeter, level of termination of nerve and its depth from skin at a particular site. Results: CSA ranged from 0.22-0.35±0.028cm2 and perimeter ranged from 15.23 – 30.33±2.92 mm The mean CSA of SN was equal on both sides ie. 0.27± 0.028 cm2 on right and 0.27±-0.025 cm2 on left. The perimeter of SN on right side was 21.27±2.92 mm and left side 20.29±2.05 mm. The depth of SN from skin on right side was 19.16±1.70 mm while on left side 19.16±1.70mm. The level of termination was 77.65±4.31 mm on right side while 77.26±4.43 mm on left side proximal to popliteal crease. Rt. SN mean CSA was almost equal among males and females whereas Lt. SN mean CSA was found to be significantly (p-value-0.048) greater in males as compared to females. The perimeter of nerve had significantly (0.043) larger values on both right and left side in females as compared to males. The depth of SN from skin was slightly more in males as compared to females while level of termination was bilaterally almost similar in both males and females. Conclusion: Normal values of various parameters of sciatic nerve evaluated in our study will be helpful in guiding and facilitating popliteal block in various surgeries

Popliteal Versus Local Field Block for Pain-Related Postoperative Unplanned Emergency Room Visits After Foot and Ankle Surgery

Ultrasound-guided popliteal blocks for postoperative pain management have grown in popularity within foot and ankle surgery. The purpose of this study was to evaluate the efficacy of popliteal block in preventing postoperative emergency department visits after foot and ankle surgery. We compared rates of presentation to the emergency department for pain following foot and ankle surgery between surgeries with a popliteal block and those with local field block alone. We identified 101 charts, of which 26 presented to the emergency department for postoperative pain following popliteal block. Our results demonstrated that popliteal blocks did not perform better than local blocks, and that there is no statistically significant difference between the 2 methods of postoperative pain control in terms of rates of presentation to the emergency department for pain. Levels of Evidence: Level III, All statistical analyses were carried out using the R statistical package by the primary author (NS) (R Developmental, Core Team. R: A Language and Environment for Statistical Computing, 2012. http://www.R-project.org ).