Saphenous Nerve Block: Single Shot Versus Continuous Infusion to Supplement a Continuous Sciatic Nerve Block After Major Ankle Surgery

Not Applicable

Completed

• Conditions: Major Ankle Surgery
• Interventions: Procedure: Continuous saphenous nerve block; Procedure: Placebo

• Registration Number: NCT01445210
• Lead Sponsor: University of Aarhus

Brief Summary

The most useful method to manage pain after major ankle surgery is infusion of local analgesics with a catheter close to the sciatic nerve.

Sensation from the ankle are carried by three nerves: The tibial and peroneal nerve (unified in the sciatic nerve) and the saphenous nerve.

Study purpose is to test whether continuous infusion of local analgesics by saphenous nerve catheter provide a better treatment of pain in comparison with a single injection nerve block. In addition cost-effectiveness of the two methods are compared.

The 50 patients of the trial are randomized in clusters of ten. We intend to do a preliminary analysis of the data from the first 40 patients. However, it is not an interim analysis. Fifty patients will be included independent of the result of the preliminary analysis. The random allocation of the last 10 patients will also be double-blinded.

Detailed Description

Major ankle surgery are known to be very painful the first 48 hours after the operation due to surgical oedema. This pain is difficult to control with systemic analgesics. Pain relief with systemic analgesics requires high doses of intravenous opioids and is associated with breakthrough pain and adverse effects of opioids (sedation, nausea, vomiting, obstipation, urinary retention, respiratory depression).

Continuous, peripheral nerve block with catheter technique for two days minimizes the need for systemic analgesics. Today such a continuous sciatic nerve block is part of the standard pain treatment after major ankle surgery on Aarhus University Hospital. Despite accurate placement of the catheter many patients are in great pain because the saphenous nerve remain unaffected. A single injection block relieve the pain but a block with Ropivacaine only last 8-15 hours.

Severe postoperative pain leads to high opioid dosages, cognitive blurring, nausea, vomiting, reduced ambulation, increased surgical stress response and increased morbidity. Pain problems and adverse effects prolongs postoperative observation time and maybe also time to discharge.

The aim of the study establish whether continuous saphenous nerve block is efficient (pain relief or reduced opioid consumption) and justified (cost-effectiveness analysis) compared with single injection block.

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study Start: 2011-09
• Study First Submitted: 2011-09-29
• Study First Submitted QC: 2011-09-30
• Study First Posted: 2011-10-03
• Status Verified: 2012-10
• Primary Completion: 2012-10
• Study Completion: 2012-10
• Last Update Submitted: 2012-10-18
• Last Update Posted: 2012-10-19

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 50

Inclusion Criteria

Elective major ankle surgery

• total ankle arthroplasty
• subtalar fusion
• ankle fusion (non arthroscopic)

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Exclusion Criteria

• coagulation abnormalities
• infection in the region of needle insertion
• systemic infection
• preoperative consumption of high dose opioid
• preoperative sciatic or femoral nerve neuropathy
• preoperative sensory deficit in either of the lower extremities
• Charcot-Marie-Tooth disorder
• diabetic neuropathy
• severe peripheral vascular disease
• allergy to local anesthetics
• lack of understanding of Numeric Rank Scale (NRS)
• communication problems
• dementia
• body mass index above 35
• bilateral continuous sciatic nerve block
• lack of consent

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
0,2% Ropivacaine	Continuous saphenous nerve block	Patients randomized to the experimental group receive a continuous infusion of 0,2 % Ropivacaine by elastomeric infusion pump at 5 ml/h in the saphenous catheter after major ankle surgery. Infusion for 48 postoperative hours. All patients receive a preoperative single shot of Ropivacaine around saphenous and sciatic nerve and a postoperative continuous sciatic nerve block.
Control	Placebo	Patients randomized to the control group receive a continuous infusion of isoton saline by elastomeric infusion pump at 5 ml/h in their catheter after major ankle surgery. Infusion for 48 postoperative hours. All patients receive a preoperative single shot of Ropivacaine around saphenous and sciatic nerve and a postoperative continuous sciatic nerve block.

Primary Outcome Measures

Name	Time	Method
Accumulated opioid consumption	First 48 hours postoperative

Secondary Outcome Measures

Name	Time	Method
Success rate for saphenous nerve analgesia	Postoperative, first 48 hours	Pain rated by NRS and opioid consumption
Success rate for clinical analgesia of foot and ankle	Postoperative, first 48 hours	Pain rated by NRS and opioid consumption
Success rate for tibial and peroneal nerve block	Postoperative, first 48 hours	Pain rated by NRS and test of sensation on the toes
Localisation of worst pain	Postoperative, first 48 hours
Cost-effectiveness	2 first postoperative days

Trial Locations

Locations (1)

Aarhus University Hospital; 🇩🇰 Aarhus, Denmark