Musculoskeletal Diseases or Conditions
Conditions
Keywords
Popliteal Sciatic nerve block
Brief summary
This study aims to assess the effect of twin subparaneural injection into individual paraneural sheaths of Common Peroneal Nerve (CPN) and Tibial Nerve (TN) below their point of divergence from the sciatic nerve on the sensory motor blockade after Popliteal Sciatic Nerve Block (PSNB) at the popliteal fossa (back of the thigh) for patients requiring lower limb surgeries.
Detailed description
Ultrasound (US) guided Popliteal Sciatic Nerve Block (PSNB) has been routinely used to provide surgical anaesthesia for ankle and foot surgeries, and the introduction of ultrasound (US) guidance has improved the ease and accuracy of performing PSNB. However, the challenge of achieving the optimal 'readiness for surgery' time after the US guided PSNB continues to confront anaesthesiologists. Cumulative evidence indicates that a subparaneural PSNB improves sensory motor block outcome when compared to subepimyseal PSNB where the local anaesthetic is deposited outside the paraneural sheath. While these are encouraging results, producing sensory motor blockade, i.e. surgical anaesthesia in the area innervated by the sciatic nerve within 30 minutes of local anaesthetic (LA) injection, after a subparaneural PSNB, remains a challenge with the success rate varying from 62-92%. Reasons for this shortcoming, despite LA being deposited in subparaneural space, close to the epineurium of the sciatic nerve, is probably multifactorial as the nerve size, surface area exposed to local anaesthetic, and internal architecture (the connective tissue component) of the sciatic nerve and its branches are all seems to influence block onset time and completeness. It was observed from our clinical practice that distal subparaneural injection (twin halo) into individual paraneural sheaths of common peroneal nerve (CPN) and tibial nerve (TN) below the point of divergence at the popliteal fossa demonstrated a faster sensory motor blockade after PSNB. Therefore, this study aims to assess the effect of twin subparaneural injection into individual paraneural sheaths of CPN and TN below their point of divergence from the sciatic nerve on the sensory motor blockade after PSNB at the popliteal fossa.
Interventions
PROCEDUREPopliteal Sciatic nerve block
Patients schedule for lower limb surgery under regional anesthesia will receive ultrasound guided subparaneural popliteal sciatic nerve block. After identification of the common peroneal nerve and tibial nerve, local anesthetic agents will be injected close to each nerve below the point of divergence at the popliteal fossa. The spread of the drug and the sensory and motor function of that limb will be assessed regularly till it is ready for surgery.
Sponsors
Chinese University of Hong Kong
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* American Society of Anesthesiologists (ASA) physical status I-III scheduled to undergo elective foot and/or ankle surgery under regional anesthesia.
Exclusion criteria
* Patient refusal, ASA physical status \> Ⅲ, pregnancy, neuromuscular disorder, prior surgery in the popliteal fossa, coagulopathy, allergy to local anaesthetic drugs, and skin infection at the site of needle insertion.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| the percentage of patients with complete sensory and motor block at 30 min | within 45 minutes after the block (at 5min, 10min, 15min, 20 min, 25min, 30min, 45 min) | VRS=0 for both sensory and motor score at 30 min. The extent of the sensory blockade will be graded according to VRS (verbal rating scale) for sensory assessment (100 = normal sensation to 0 = no sensation) in the areas innervated by the sciatic nerve. Motor blockade of the deep peroneal nerve (dorsal flexion of the ankle) and tibial nerve (plantar flexion of the ankle) will be graded using a 3-point scale: 2 = normal, 1 = paresis, and 0 = paralysis. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| The time taken to complete sensory and motor blockade at 30 min, time to 'readiness for surgery' | within 45 minutes after the block (at 5min, 10min, 15min, 20 min, 25min, 30min, 45min) | The time point where the sensory block was =\< 30 VRS (VRS 0-100, 100=normal sensation and 0= no sensation) and a motor blockade of =\< 1 (2=normal, 1=paresis, 0=paralysis), |
| Success rate of the block | within 45 minutes after the block (at 5min, 10min, 15min, 20min, 25min, 30min, 45min) | complete abolition of sensation to cold and paralysis of the muscles in the ipsilateral calf and foot |
| Complication | from immediately after the block till 24 hours afterwards | any local anesthetic toxicity |
| Paraesthesia and degree of discomfort | during the block | Paresthesia (yes or no); degree if discomfort (numeric rating scale 0-100) |
Countries
Hong Kong
Outcome results
None listed