Postoperative PainPhase 4NCT01579747
Does Ultrasound Improve Procedural Time in the Lateral Popliteal Approach to the Sciatic Nerve in Obese Patients
A Phase 4 study testing Ultrasound and Nerve stimulation in people with Postoperative Pain, run by University of New Mexico at 1 site in United States.
Trial summary
Ultrasound have been shown to improve the time needed to locate and block nerves in the non obese population. However, its utility is still unknown in the obese population. Ultrasound is known to produce poorer quality images in the obese population. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Postoperative Pain
- What is being tested?
- Ultrasound and Nerve stimulation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 25 participants
- Where
- 1 siteUnited States
- Study dates
- Jul 2012to Mar 2013
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- ASA 1-3
- Age 18 and above
- BMI >30
- Operations requiring lateral popliteal approach to the sciatic nerve block
Who cannot join
- Diabetes
- Injection site deformities
- infection at the injection site
- existing peripheral neuropathy
- allergy to LA agents
- Dementia or communication problems
- Inability to understand or discern temperature difference
- Any other contraindication to lower limb peripheral nerve block
Trial locations and contacts
1 site in 1 country.
United States1 site
University of New Mexico Hospital
Albuquerque, New Mexico, 87106
About this study
Ultrasound have been shown to improve the time needed to locate and block nerves in the non obese population. However, its utility is still unknown in the obese population. Ultrasound is known to produce poorer quality images in the obese population. This study aims to find out if it is a better tool for nerve localization compared to the traditional nerve stimulation technique.
Read the detailed description
This is a single blinded randomized controlled trial comparing the procedural time for a sciatic nerve block via the lateral popliteal approach using ultrasound compared with nerve stimulation.
24 patients will be randomly selected to determine if the patient will receive their sciatic block using an ultrasound or a nerve stimulation technique.
Patients chosen to receive the ultrasound technique will have their blocks performed by attending regional anesthesiologist who are experts at ultrasound guided sciatic nerve blocks via the lateral popliteal approach.
Patients chosen to receive the nerve stimulation technique will have their blocks performed by attending regional anesthesiologist who are experts at nerve stimulation sciatic nerve blocks via the lateral popliteal approach.
Blinding:
Both the patient and the person assessing the block will be blinded to the group allocation. The highest pain score during the procedure will be obtained by an observer blinded to the group allocation. The time taken for the block, the number of skin punctures and number of passes will be recorded by a person who is not performing the block.
All popliteal blocks will be performed preoperatively by 1 of 4 staff anesthesiologists with substantial expertise in both peripheral nerve localization techniques. Patients will be in the supine position with a bolster below the calf keeping the tibia parallel to the floor. This allows placement of the ultrasound probe in the popliteal region in the ultrasound group. An ultrasound machine and a nerve stimulator will be set up in both groups and the patient will be blinded on the technique used for nerve localization. The ultrasound machine will be turned on and placed perpendicular to the anesthesiologist performing the block on the opposite side of the leg being blocked. The nerve stimulator will be turned on and a grounding lead place on the side of the leg being blocked for both groups. The anesthesiologist performing the block will be given the allocation only after the set up of both systems and just prior to commencement of the block. The patient will be sedated with 2-5mg midazolam and 50-200 ug fentanyl to achieve anxiolysis while maintaining verbal contact. A screen will be set up to prevent the patient or the person assessing the block from seeing the block or the ultrasound screen.
Nerve stimulation group:
Time of block performance starts from first palpation of landmarks to the final injection of local anesthetics. The site of needle insertion was identified and marked (Surgical Skin Marker VX100; Vio Healthcare, Hailsham, East Sussex, UK) as the groove between the biceps femoris and vastus lateralis muscle 10 cm above the top of the patella. (4) A 22G 80mm (SonoPlex Stim Cannula Pajunk Medizintechnologie Germany) insulated needle is inserted with a nerve stimulator set at 1.0mA. The needle is inserted perpendicular to the skin and redirected at a 30 degree angle relative to the horizontal plane. The needle depth is estimated using the midpoint of the thigh and the tangential trajectory of 30 degrees. If plantar flexion is elicited, the nerve stimulator is dialed down to produce a stimulation at 0.4mA or less. If stimulation persists at 0.2mA, the needle is withdrawn until stimulation disappears at 0.2mA but persists below 0.4mA. If dorsiflexion is elicited, the needle is inserted deeper to achieve plantarflexion. Internal rotation of the leg may be help in achieving the angulation.(4) If the needle does not achieve any stimulation, the needle is redirected in 5 degree increments between a 15 to 45 degree trajectory. (5) When the needle is in the correct position, 20 cc of 1.5% mepivacaine is injected in 5 cc increments over 30 seconds. Aspiration for blood is performed before injection and after every 5 cc of injection. Injection is stopped if blood is aspirated or if there is pain on injection. The needle is then repositioned or the block abandoned on the discretion of the anesthesiologist doing the block. However, blood aspiration or pain will be noted.
Ultrasound group
Time of block performance starts from the first antiseptic skin prep on the patient to the final injection of local anesthetics. The lateral and posterior portion of the thigh will be prepped with chlorhexidine. The ultrasound probe is covered with a sterile dressing and placed in the popliteal fossa close to the popliteal crease. The tibial and common peroneal nerve is identified. A long axis slide in the cephalad direction is performed to identify the unity of the tibial and common peroneal nerve into the sciatic nerve. The 28 mm high frequency ultrasound probe is then then moved 2 or more cm cephalad and this is the level of the needle insertion. The 22G 80mm (SonoPlex Stim Cannula Pajunk Medizintechnologie Germany) needle is inserted in-plane from the lateral thigh to approach the sciatic nerve. (6) 20 cc of 1.5% mepivacaine is injected in 5 cc increments over 30 seconds. Aspiration for blood is performed before injection and after every 5 cc of injection. Circumferential spread of local anesthetics around the nerve is sought. The needle is redirected as required to achieve this goal. Injection is stopped if blood is aspirated or if there is pain on injection. The needle is then repositioned or the block abandoned on the discretion of the anesthesiologist doing the block. However, blood aspiration or pain will be noted.
Block Evaluation After the placement of the block, the tibial (bottom of the foot) and common peroneal (top of the foot) will be assessed for motor and sensory loss. Motor loss will be graded as such: 0= no motor strength; 1 = some loss, 2 = full strength. using ice in a PVC glove every 5 minutes for 30 minutes. Sensory loss will be graded as such: 0 = no sensation to ice; 1 = some loss; 2= complete sensation to ice. If the block does not produce complete sensory loss in both distribution within 30 minutes, the block is defined as a failure. It is up to the discretion of the anesthesiologist if he wishes to perform a rescue block or supplement with local field block or to perform a general anesthesia.
Other Evaluation Patients will be followed up in recovery to evaluate if general anesthetic or supplemental local anesthetic by the surgeon is required in the sciatic distribution for surgery.
Patients will be followed up within 72 hours via a telephone interview with regards to signs and symptoms of infection and nerve damage.
- Conditions
- Postoperative Pain
- Being tested
- Ultrasound, Nerve stimulation
- Keywords
- nerve stimulation, ultrasound, sciatic nerve block, popliteal block, obese
- Medical subject headings
- Pain, Postoperative, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
UltrasoundProcedure or surgery
Using ultrasound for nerve localization when performing a sciatic nerve block via the lateral popliteal approach
Nerve stimulationProcedure or surgery
Using nerve stimulation for nerve localization in sciatic nerve blocks via the lateral popliteal approach
| Study group | Role | What they receive |
|---|---|---|
| Nerve stimulation sciatic nerve block | Placebo comparator | Time taken to complete a sciatic nerve block via the lateral popliteal approach using nerve stimulation Receives: Procedure: Nerve stimulation |
| Ultrasound guided sciatic nerve block | Active comparator | Time taken to complete a sciatic nerve block via the lateral popliteal approach when using an ultrasound Receives: Procedure: Ultrasound |
What is being measured
The primary outcome is the main question the study is designed to answer.
Procedural Time
Time taken to complete a sciatic nerve block via the lateral popliteal approach using ultrasound vs nerve stimulation technique
Measured: less than 30 minutes
Secondary outcomes (1)
Number of Redirections
Number of needle redirections defined as needle withdrawal followed by advancement as an intentional movement.
Measured: 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Apr 2012 (estimated)
- Study startJul 2012
- Primary completionDec 2012
- Study completionMar 2013
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Postoperative PainStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of New Mexico
- Sponsor type
- University, hospital or other
- Collaborators
- VA Palo Alto Health Care System
- Responsible party
- Principal investigator, Nicholas Lam, University of New Mexico
- Investigators
- Nicholas Lam, MD, Principal investigator, University of New Mexico
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01579747
- Sponsor's protocol ID
- UNMLAM_USvsNSobese
- Status last verified
- Dec 2013
- First submitted
- 16 Apr 2012
- Last updated
- 24 Jan 2014
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Jan 2014. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Does Ultrasound Improve Procedural Time in the Lateral Popliteal Approach to the Sciatic Nerve in Obese Patients
- ClinicalTrials.gov ID
- NCT01579747
- Acronym / sponsor ID
- UNMLAM_USvsNSobese
- Conditions
- Postoperative Pain
- Keywords
- nerve stimulation, ultrasound, sciatic nerve block, popliteal block, obese
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 25 participants (actual)
- Lead sponsor
- University of New MexicoUniversity, hospital or other
- Collaborators
- VA Palo Alto Health Care System
- Study start
- Jul 2012
- Primary completion
- Dec 2012 (actual)
- Study completion
- Mar 2013 (actual)
- First posted
- 18 Apr 2012 (estimated)
- Results
- Posted 19 Dec 2013
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Ultrasound have been shown to improve the time needed to locate and block nerves in the non obese population. However, its utility is still unknown in the obese population. Ultrasound is known to produce poorer quality images in the obese population. This study aims to find out if it is a better tool for nerve localization compared to the traditional nerve stimulation technique.
Detailed description
This is a single blinded randomized controlled trial comparing the procedural time for a sciatic nerve block via the lateral popliteal approach using ultrasound compared with nerve stimulation.
24 patients will be randomly selected to determine if the patient will receive their sciatic block using an ultrasound or a nerve stimulation technique.
Patients chosen to receive the ultrasound technique will have their blocks performed by attending regional anesthesiologist who are experts at ultrasound guided sciatic nerve blocks via the lateral popliteal approach.
Patients chosen to receive the nerve stimulation technique will have their blocks performed by attending regional anesthesiologist who are experts at nerve stimulation sciatic nerve blocks via the lateral popliteal approach.
Blinding:
Both the patient and the person assessing the block will be blinded to the group allocation. The highest pain score during the procedure will be obtained by an observer blinded to the group allocation. The time taken for the block, the number of skin punctures and number of passes will be recorded by a person who is not performing the block.
All popliteal blocks will be performed preoperatively by 1 of 4 staff anesthesiologists with substantial expertise in both peripheral nerve localization techniques. Patients will be in the supine position with a bolster below the calf keeping the tibia parallel to the floor. This allows placement of the ultrasound probe in the popliteal region in the ultrasound group. An ultrasound machine and a nerve stimulator will be set up in both groups and the patient will be blinded on the technique used for nerve localization. The ultrasound machine will be turned on and placed perpendicular to the anesthesiologist performing the block on the opposite side of the leg being blocked. The nerve stimulator will be turned on and a grounding lead place on the side of the leg being blocked for both groups. The anesthesiologist performing the block will be given the allocation only after the set up of both systems and just prior to commencement of the block. The patient will be sedated with 2-5mg midazolam and 50-200 ug fentanyl to achieve anxiolysis while maintaining verbal contact. A screen will be set up to prevent the patient or the person assessing the block from seeing the block or the ultrasound screen.
Nerve stimulation group:
Time of block performance starts from first palpation of landmarks to the final injection of local anesthetics. The site of needle insertion was identified and marked (Surgical Skin Marker VX100; Vio Healthcare, Hailsham, East Sussex, UK) as the groove between the biceps femoris and vastus lateralis muscle 10 cm above the top of the patella. (4) A 22G 80mm (SonoPlex Stim Cannula Pajunk Medizintechnologie Germany) insulated needle is inserted with a nerve stimulator set at 1.0mA. The needle is inserted perpendicular to the skin and redirected at a 30 degree angle relative to the horizontal plane. The needle depth is estimated using the midpoint of the thigh and the tangential trajectory of 30 degrees. If plantar flexion is elicited, the nerve stimulator is dialed down to produce a stimulation at 0.4mA or less. If stimulation persists at 0.2mA, the needle is withdrawn until stimulation disappears at 0.2mA but persists below 0.4mA. If dorsiflexion is elicited, the needle is inserted deeper to achieve plantarflexion. Internal rotation of the leg may be help in achieving the angulation.(4) If the needle does not achieve any stimulation, the needle is redirected in 5 degree increments between a 15 to 45 degree trajectory. (5) When the needle is in the correct position, 20 cc of 1.5% mepivacaine is injected in 5 cc increments over 30 seconds. Aspiration for blood is performed before injection and after every 5 cc of injection. Injection is stopped if blood is aspirated or if there is pain on injection. The needle is then repositioned or the block abandoned on the discretion of the anesthesiologist doing the block. However, blood aspiration or pain will be noted.
Ultrasound group
Time of block performance starts from the first antiseptic skin prep on the patient to the final injection of local anesthetics. The lateral and posterior portion of the thigh will be prepped with chlorhexidine. The ultrasound probe is covered with a sterile dressing and placed in the popliteal fossa close to the popliteal crease. The tibial and common peroneal nerve is identified. A long axis slide in the cephalad direction is performed to identify the unity of the tibial and common peroneal nerve into the sciatic nerve. The 28 mm high frequency ultrasound probe is then then moved 2 or more cm cephalad and this is the level of the needle insertion. The 22G 80mm (SonoPlex Stim Cannula Pajunk Medizintechnologie Germany) needle is inserted in-plane from the lateral thigh to approach the sciatic nerve. (6) 20 cc of 1.5% mepivacaine is injected in 5 cc increments over 30 seconds. Aspiration for blood is performed before injection and after every 5 cc of injection. Circumferential spread of local anesthetics around the nerve is sought. The needle is redirected as required to achieve this goal. Injection is stopped if blood is aspirated or if there is pain on injection. The needle is then repositioned or the block abandoned on the discretion of the anesthesiologist doing the block. However, blood aspiration or pain will be noted.
Block Evaluation After the placement of the block, the tibial (bottom of the foot) and common peroneal (top of the foot) will be assessed for motor and sensory loss. Motor loss will be graded as such: 0= no motor strength; 1 = some loss, 2 = full strength. using ice in a PVC glove every 5 minutes for 30 minutes. Sensory loss will be graded as such: 0 = no sensation to ice; 1 = some loss; 2= complete sensation to ice. If the block does not produce complete sensory loss in both distribution within 30 minutes, the block is defined as a failure. It is up to the discretion of the anesthesiologist if he wishes to perform a rescue block or supplement with local field block or to perform a general anesthesia.
Other Evaluation Patients will be followed up in recovery to evaluate if general anesthetic or supplemental local anesthetic by the surgeon is required in the sciatic distribution for surgery.
Patients will be followed up within 72 hours via a telephone interview with regards to signs and symptoms of infection and nerve damage.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Nerve stimulation sciatic nerve block | Placebo comparator | Procedure: Nerve stimulationTime taken to complete a sciatic nerve block via the lateral popliteal approach using nerve stimulation |
| Ultrasound guided sciatic nerve block | Active comparator | Procedure: UltrasoundTime taken to complete a sciatic nerve block via the lateral popliteal approach when using an ultrasound |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- ASA 1-3
- Age 18 and above
- BMI >30
- Operations requiring lateral popliteal approach to the sciatic nerve block
Key exclusion criteria (8 listed)
- Diabetes
- Injection site deformities
- infection at the injection site
- existing peripheral neuropathy
- allergy to LA agents
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| UltrasoundUsing ultrasound for nerve localization when performing a sciatic nerve block via the lateral popliteal approach | Procedure or surgery | Ultrasound guided sciatic nerve block |
| Nerve stimulationUsing nerve stimulation for nerve localization in sciatic nerve blocks via the lateral popliteal approach | Procedure or surgery | Nerve stimulation sciatic nerve block |
Primary outcome
Procedural Time
Time frame: less than 30 minutes
Time taken to complete a sciatic nerve block via the lateral popliteal approach using ultrasound vs nerve stimulation technique
1 secondary outcome
Number of Redirections
Time frame: 6 months
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Jan 2014.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Related trials for Postoperative Pain
RecruitingPhase 4
ESP Blocks for Posterior Spinal Fusion
Postoperative Pain
Recruiting
Effect of Cryotherapeutic and Nanotherapeutic Sodium Hypochlorite on Post-Operative Endodontic Pain.
Symptomatic Irreversible Pulpitis, Symptomatic Apical Periodontitis
RecruitingPhase 2
REctus Sheath Trial
Acute Pain, Postoperative Pain, Acute
Not yet recruiting
Effect of Pectoral Nerve Block (PECS) Using Magnesium Sulfate Added to Dexamethasone on Quality of Recovery and Chronic Post-Mastectomy Pain
Breast Cancer, Postoperative Pain
Active, not recruitingPhase 4
Effect of Dexmedetomidine on Postoperative Pain in Spinal Anesthesia for Cesarean Section at Assuit University Hospital
Cesarean Section
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Nicholas Lam, MD principal investigator
University of New Mexico
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Ultrasound and Nerve stimulation in people with Postoperative Pain, run by University of New Mexico at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 24 Jan 2014. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 19 Dec 2013). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Procedural Time (time frame: less than 30 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Jan 2014.