The Duration of Motor Block May Vary Between 12-36 Hrs
Conditions
Brief summary
The duration of motor block for infragluteal parabiceps sciatic nerve block following total knee replacement may vary between 12-36 hrs depending on the amount of local anesthetic given.
Interventions
DRUGBupivacaine
Varying doses to determine the duration of analgesia
DRUGRopivacaine
Varying doses to determine the duration of analgesia
Sponsors
Northwestern University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
SUPPORTIVE_CARE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* Adult patients (\>18 years of age) who are undergoing elective total knee arthroplasty will be included in the study.
Exclusion criteria
*
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | 3 days | Subject reported and investigator measured motor and sensory blockade of the sciatic nerve with less than 10ml of 0.5% bupivacaine and ropivacaine after ultrasound-guided nerve-stimulator-assisted needle positioning beneath the common investing external layer (CIEL). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cumulative Probabilities for Needle Positioning Above and Below CIEL. | 1 Day | The cumulative probability distributions for the minimal current to evoke a motor response with the needle tip positioned external (above) to the common investing extraneural layer (CIEL) and the cumulative probability distribution for the needle tip postioned internal (below) to the CIEL were sought. The difference in the mean minimum threshold current (mA) for the external (above) and internal (below) CIEL positioning were calculated. |
Countries
United States
Participant flow
Recruitment details
Subjects undergoing primary tricompartmental total knee replacement at Northwestern Memorial Hospital were asked to participate. 174 patients were approached. 142 subjects were recruited to participate.
Pre-assignment details
Exclusion criteria: subject refusal to be included in the study, contraindications to regional anesthesia, inability to elicit an evoked motor response less than or equal to 1 mA, history of allergy to amide local anesthetics, presence of a progressive neurological deficit, opioid tolerant subjects, presence of coagulopathy, infection, or pregnancy
Participants by arm
| Arm | Count |
|---|---|
| GROUP 1 Varying does to determine duration of analgesia following a sciatic nerve block
Bupivacaine : Varying doses to determine the duration of analgesia | 69 |
| GROUP 2 Varying does to determine duration of analgesia following a sciatic nerve block
Ropivacaine : Varying doses to determine the duration of analgesia | 70 |
| Total | 139 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Protocol Violation | 2 | 1 |
Baseline characteristics
| Characteristic | GROUP 2 | GROUP 1 | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 36 Participants | 37 Participants | 73 Participants |
| Age, Categorical Between 18 and 65 years | 34 Participants | 32 Participants | 66 Participants |
| Age, Continuous | 64.70 years STANDARD_DEVIATION 9.26 | 66.93 years STANDARD_DEVIATION 9.21 | 65.81 years STANDARD_DEVIATION 9.27 |
| Region of Enrollment United States | 70 participants | 69 participants | 139 participants |
| Sex: Female, Male Female | 43 Participants | 44 Participants | 87 Participants |
| Sex: Female, Male Male | 27 Participants | 25 Participants | 52 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 69 | 0 / 70 |
| serious Total, serious adverse events | 0 / 69 | 0 / 70 |
Outcome results
Primary
Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL
Subject reported and investigator measured motor and sensory blockade of the sciatic nerve with less than 10ml of 0.5% bupivacaine and ropivacaine after ultrasound-guided nerve-stimulator-assisted needle positioning beneath the common investing external layer (CIEL).
Time frame: 3 days
| Arm | Measure | Group | Value (MEDIAN) |
|---|---|---|---|
| Above CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Motor: < 10ml | 10 Hours |
| Above CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Motor: >/= 10ml | 21 Hours |
| Above CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Sensory: <10ml | 9 Hours |
| Above CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Sensory: >/= 10ml | 20 Hours |
| Below CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Sensory: >/= 10ml | 14 Hours |
| Below CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Motor: < 10ml | 7 Hours |
| Below CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Sensory: <10ml | 8 Hours |
| Below CIEL | Duration of Motor and Sensory Block of the Sciatic With 0.5% Bupivacaine and Ropivacaine After Ultrasound-guided Nerve-stimulator-Assisted Needle Positioning Beneath the CIEL | Motor: >/= 10ml | 15 Hours |
Comparison: The sample selected for this study,70 per drug group (or 10 in each of the 7 groups), achieves 88% power to detect a minimal difference of 4 hours in duration at a significance level (α) of 0.05 and a standard deviation of 3 hours using Williams test. We chose a difference of 4 hours as this was the interval used for assessment in the postoperative period at night. We sought to detect a difference that was equal to 1 observation period difference.p-value: 0.0595% CI: [-17, -6]Wilcoxon (Mann-Whitney)
Comparison: The sample selected for this study,70 per drug group (or 10 in each of the 7 groups), achieves 88% power to detect a minimal difference of 4 hours in duration at a significance level (α) of 0.05 and a standard deviation of 3 hours using Williams test. We chose a difference of 4 hours as this was the interval used for assessment in the postoperative period at night. We sought to detect a difference that was equal to 1 observation period difference.p-value: 0.0595% CI: [-15, -6]Wilcoxon (Mann-Whitney)
Comparison: The sample selected for this study,70 per drug group (or 10 in each of the 7 groups), achieves 88% power to detect a minimal difference of 4 hours in duration at a significance level (α) of 0.05 and a standard deviation of 3 hours using Williams test. We chose a difference of 4 hours as this was the interval used for assessment in the postoperative period at night. We sought to detect a difference that was equal to 1 observation period difference.p-value: 0.0595% CI: [-10, -4]Wilcoxon (Mann-Whitney)
Comparison: The sample selected for this study,70 per drug group (or 10 in each of the 7 groups), achieves 88% power to detect a minimal difference of 4 hours in duration at a significance level (α) of 0.05 and a standard deviation of 3 hours using Williams test. We chose a difference of 4 hours as this was the interval used for assessment in the postoperative period at night. We sought to detect a difference that was equal to 1 observation period difference.p-value: 0.0595% CI: [-7, -2]Wilcoxon (Mann-Whitney)
Secondary
Cumulative Probabilities for Needle Positioning Above and Below CIEL.
The cumulative probability distributions for the minimal current to evoke a motor response with the needle tip positioned external (above) to the common investing extraneural layer (CIEL) and the cumulative probability distribution for the needle tip postioned internal (below) to the CIEL were sought. The difference in the mean minimum threshold current (mA) for the external (above) and internal (below) CIEL positioning were calculated.
Time frame: 1 Day
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Above CIEL | Cumulative Probabilities for Needle Positioning Above and Below CIEL. | 0.52 Amplitude (mA) |
| Below CIEL | Cumulative Probabilities for Needle Positioning Above and Below CIEL. | 0.19 Amplitude (mA) |
p-value: <0.00195% CI: [0.49, 0.54]Z score
p-value: <0.00195% CI: [0.18, 0.21]Z score