Clinical trial NCT01814605: Sciatic Nerve Block Using the Subgluteal Space Approach: A Comparison With the Infragluteal Approach
Official title: Ultrasound-guided Sciatic Nerve Block Using the Subgluteal Space Injection Approach: A Comparison With the Infragluteal Approach
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Neuromuscular Blockade
Keywords: Sciatic Nerve Block
Subgluteal space
Infragluteal space
Lead sponsor: University Health Network, Toronto
Sponsor class: OTHER
First posted: 2013-03-20
Enrollment: 27
Sex: ALL
Minimum age (years): 18
Maximum age (years): 85
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: FACTORIAL
Primary purpose: TREATMENT

Brief summary: A new ultrasound-guided "subgluteal space" approach to sciatic nerve block that has been recently described obviates the need to identify the sciatic nerve. The investigators hypothesize that the use of an ultrasound-guided subgluteal space injection to perform sciatic nerve block will increase the proportion of patients experiencing complete sensory block in both terminal branches of the Sciatic nerve in comparison to the same proportion in those who receive the block via ultrasound-guided infragluteal approach with circumferential injection in patients scheduled for unilateral TKA(total knee arthroplasty) surgeries.

Detailed description: The subgluteal space technique is performed by injecting local anesthetics in the space sandwiched between the gluteus maximus and biceps femoris muscle at the level of the greater trochanter and ischial tuberosity rather than circumferentially around the nerve. The bone landmarks are particularly easier to identify because of the high acoustic mismatch and attenuation of bone. The end point of this technique is the distention of the subgluteal space to injection through the block needle. This new approach may translate in benefits including reducing block procedure time, reducing number of needle passes, reducing side effects (vascular complications), and ultimately block success.

The philosophy of injecting local anesthetics in designated anatomic spaces or between the fascial planes where nerves travel, as in the fascia iliaca block for example, is a time tested approach and has become more popular with the introduction of ultrasound because of the ease of visualizing fascia and bone in comparison to nerves under ultrasound. The call for injecting between planes and to stay away from nerves being blocked has found supporting evidence in trials involving ultrasound-guided brachial plexus block at the interscalene level.

One important potential advantage of the subgluteal space approach may be an increased safety margin created when distance is maintained between injecting needles and target nerves, an advantage that seems to make these injection techniques progressively more popular and to expand into a variety of single and continuous nerve blocks.

The investigators aim to compare the newly described ultrasound-guided subgluteal space block technique of the sciatic nerve to the currently practiced ultrasound-guided infragluteal sciatic nerve block with circumferential perineural spread in patients undergoing unilateral TKA surgery.

Eligibility criteria: Inclusion Criteria:

* English speaking
* ASA(American Society of Anesthesiologists physical status classification system) I-III patients undergoing unilateral TKA under spinal anesthesia and nerve blocks
* Ages 18-85
* BMI ≤ 38 Kg/m2

Exclusion Criteria:

* Chronic pain disorders
* Significant pre-existing neurological deficits or peripheral neuropathy affecting the lower extremity
* Abuse of drugs or alcohol
* Allergies to any medication included in the study protocol
* Contraindication to spinal anesthesia
* History of significant psychiatric conditions that may affect patient assessment
* Pregnancy

Primary outcomes:
measure: Complete sensory block in the distribution of both terminal branches of the sciatic nerve.
timeFrame: up to 30 minutes
Secondary outcomes:
measure: Block procedure time
timeFrame: until local anesthetic injection has been completed
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: Toronto Western Hospital
state: Ontario
Study officials:
affiliation: University of Toronto
name: Richard Brull, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Allen HW, Liu SS, Ware PD, Nairn CS, Owens BD. Peripheral nerve blocks improve analgesia after total knee replacement surgery. Anesth Analg. 1998 Jul;87(1):93-7. doi: 10.1097/00000539-199807000-00020.
citation: Cook P, Stevens J, Gaudron C. Comparing the effects of femoral nerve block versus femoral and sciatic nerve block on pain and opiate consumption after total knee arthroplasty. J Arthroplasty. 2003 Aug;18(5):583-6. doi: 10.1016/s0883-5403(03)00198-0.
citation: Weber A, Fournier R, Van Gessel E, Gamulin Z. Sciatic nerve block and the improvement of femoral nerve block analgesia after total knee replacement. Eur J Anaesthesiol. 2002 Nov;19(11):834-6. doi: 10.1017/s0265021502221353. No abstract available.
citation: Abdallah FW, Chan VW, Koshkin A, Abbas S, Brull R. Ultrasound-guided sciatic nerve block in overweight and obese patients: a randomized comparison of performance time between the infragluteal and subgluteal space techniques. Reg Anesth Pain Med. 2013 Nov-Dec;38(6):547-52. doi: 10.1097/AAP.0000000000000016.