(265 days)
The ODFS® Pace XL is intended to provide ankle dorsiflexion in individuals who have a dropped foot as a consequence of upper motor neuron injury. By detecting the swing phase of gait through a foot switch signal, appropriate electrical stimulation of the leg and ankle muscles may improve gait by flexing the foot of persons who have lost or impaired function. There may be additional benefits from FES such as muscle re-education, prevention/retardation of disuse atrophy, increased or maintained range of joint motion and increase in local blood flow.
The ODFS® Pace XL is a medical device and should only be used under medical supervision for the treatment of dropped foot following an upper motor neuron injury.
The ODFS® Pace XL is an external functional neuromuscular stimulator. It consists of a small, body worn, battery powered, single channel stimulator which is triggered by a footswitch worn in the shoe. The footswitch options are:
- Shoe insole incorporating wireless transceiver which provides wireless triggering
- 'Out of shoe' wireless transceiver with 'in shoe' heel switch. Provides wireless triggering.
- Wired 'in shoe' heel switch for where 1 & 2 are not appropriate or to cover an emergency, e.g. loss of battery power in wireless accessory.
The triggering element and detection is the same across all options and option 3 is common to the ODFS® Pace (predicate device).
Electrical pulses are generated by the device in order to stimulate muscle contractions in the lower limb. (Neuromuscular stimulation) Triggering with a footswitch permits the stimulation to be varied according to the gait of the user. Stimulation produces contraction of the appropriate muscles to cause dorsiflexion of the ankle in individuals who have impaired or absent ability to pick up their foot during walking as a result of a neurological injury. This paralysis affecting the foot is commonly known as 'drop foot' or 'dropped foot'.
The electrical stimulation is delivered via self adhesive skin surface electrodes. The electrodes may be flexibly placed according to the optimum response of the patient but typically are located over the common peroneal nerve as it passes near the head of the fibula. The user may be offered the below knee ODFS® Leg Cuff accessory as aid to locating electrodes repeatedly day to day. An additional option is to mount the ODFS® Pace XL upon the ODFS® Leg Cuff.
For individuals presenting with weakness and/or spasticity a muscle stimulation exercise program can be delivered by the ODFS® Pace XL. In this case the footswitch trigger is not used and the ODFS® Pace functions as a powered muscle stimulator. A clinician would determine the need for this application which can be enabled from a setup option in the ODFS® Pace XL. (Default is to have the exercise disabled)
The Odstock Medical Ltd ODFS® Pace XL device is a functional neuromuscular stimulator. The acceptance criteria and the study that proves the device meets the acceptance criteria are described below.
1. Table of acceptance criteria and the reported device performance:
The provided document K171396 is a 510(k) premarket notification of intent to market the ODFS® Pace XL. This submission does not define specific "acceptance criteria" in the sense of predefined numerical targets that the device must achieve in a clinical trial. Instead, the submission demonstrates "substantial equivalence" to legally marketed predicate devices by showing that the ODFS® Pace XL has the same intended use and similar technological characteristics, and that any differences do not raise new questions of safety and effectiveness.
The "performance data" provided focuses on the electrical output specifications of the device and its compliance with recognized standards. The comparison is primarily against the ODFS® Pace (K102115) and ODFS® III v6.2 (K050991) predicate devices.
| Feature / Acceptance Criteria | ODFS® Pace XL Reported Performance | Predicate Device (ODFS® Pace) Performance | Predicate Device (ODFS® III v6.2) Performance |
|---|---|---|---|
| Intended Use | Same as predicate | Same as predicate | Primary predicate |
| Waveform | Biphasic (symmetrical and balanced asymmetrical) | Biphasic (symmetrical and balanced asymmetrical) | Biphasic (symmetrical and balanced asymmetrical) |
| Pulsewidth | 0 - 360 microseconds (±10%) | 0 - 360 microseconds (±10%) | 7 - 365 microseconds (±10%) |
| Frequency | Default 40Hz, 20-60Hz in 5Hz steps | Default 40Hz, 20-60Hz in 5Hz steps | 40Hz ± 10% |
| Max Output Voltage | 86-140V peak (dependent on resistance) | 85-150V peak (dependent on resistance) | (Not explicitly stated in comparable format) |
| Max Output Current | 172mA @ 500R, 62mA @ 2K, 14mA @ 10K | 170mA @ 500R, 65mA @ 2K, 15mA @ 10K | (Not explicitly stated in comparable format) |
| Patient Leakage Current (<10µA normal condition, <25µA single fault) | Normal: <10µA, Single fault: <25µA | Normal: <10µA, Single fault: <25µA | Normal: <10µA, Single fault: <100µA |
| Net Charge (per pulse) | 0µC | 0µC | (Not explicitly stated) |
| Max Phase Charge @ 500R | 50µC | 50µC | (Not explicitly stated) |
| Current Density Smallest Recommended Electrodes (5cm x 5cm) | 6.9mA/cm² peak, 0.68mA/cm² RMS | 6.9mA/cm² peak, 0.68mA/cm² RMS (implied similar by current outputs) | (Not explicitly stated) |
| Power Density Smallest Recommended Electrodes (5cm x 5cm) | 0.6W/cm² peak, 5.8mW/cm² RMS | 0.6W/cm² peak, 5.8mW/cm² RMS (implied similar by voltage/current outputs) | (Not explicitly stated) |
| Software/Firmware/Microprocessor control? | Yes (V1.3) | Yes (V1.2) | No |
| Automatic Shut Off | Yes (after 4hr in 'sleep' state) | Yes (after 4hr in 'sleep' state) | No |
| Patient Override Control | Yes (Pause button) | Yes (Pause button) | Yes (Pause button) |
| Compliance with ISO 60601-1-1:2006 | Yes | Yes | Yes |
| Compliance with ISO 60601-1-2:2007 | Yes | Yes | Yes |
| Compliance with ISO 60601-2-10:2001 | Yes | Yes | Yes |
2. Sample sized used for the test set and the data provenance:
The provided document describes performance testing of the device itself to verify functional and output specifications and compliance with electrical safety standards. It does not describe a clinical study with human subjects (a "test set" in a clinical performance context).
- Test set sample size: N/A (no clinical test set as part of this submission for substantial equivalence)
- Data provenance: The performance testing was conducted by the manufacturer (Odstock Medical Ltd) and a third party for electromagnetic compatibility. The country of origin for the data is the UK. The testing described is prospective (i.e., performed on the ODFS® Pace XL device).
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
N/A - This submission is not based on a clinical study where expert ground truth establishment would be required. The "ground truth" for the device's electrical performance and safety is derived from established engineering principles and international standards.
4. Adjudication method for the test set:
N/A - Not applicable as there was no clinical test set requiring adjudication.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, if so, what was the effect size of how much human readers improve with AI vs without AI assistance:
N/A - This is not an AI-assisted diagnostic device. No MRMC study was conducted or described.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
N/A - This is a medical device for functional neuromuscular stimulation, not an algorithm. The "standalone" performance relates to the device's adherence to its electrical and functional specifications, which was tested.
7. The type of ground truth used:
The "ground truth" for this submission are the engineering specifications and international standards for electrical medical devices. For example:
- The voltage, current, pulse width, and frequency outputs were measured against the device's designed specifications.
- The patient leakage current limits were measured against the requirements of ISO 60601-1.
- Electromagnetic compatibility was assessed against ISO 60601-1-2.
- Safety requirements for nerve and muscle stimulators were assessed against ISO 60601-2-10.
8. The sample size for the training set:
N/A - This is a hardware device; the concept of a "training set" in the context of machine learning does not apply here.
9. How the ground truth for the training set was established:
N/A - Not applicable.
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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: the Department of Health & Human Services logo on the left and the FDA logo on the right. The FDA logo features the letters 'FDA' in a blue square, followed by the words 'U.S. FOOD & DRUG ADMINISTRATION' in blue text.
January 31, 2018
Odstock Medical Ltd Steven Crook Quality and Regulatory Manager Salisbury District Hospital Salisbury, Wiltshire, SP2 8BJ UK
Re: K171396
Trade/Device Name: ODFS Pace XL Regulation Number: 21 CFR 882.5810 Regulation Name: External Functional Neuromuscular Stimulator Regulatory Class: Class II Product Code: GZI, IPF Dated: October 27, 2017 Received: November 13, 2017
Dear Steven Crook:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803); good
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manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely.
Vivek J. Pinto -S
for Carlos L. Peña, PhD, MS Director Division of Neurological and Physical Medicine Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K171396
Device Name ODFS® Pace XL
Indications for Use (Describe)
The ODFS® Pace XL is intended to provide ankle dorsiflexion in individuals who have a dropped foot as a consequence of upper motor neuron injury. By detecting the swing phase of gait through a foot switch signal, appropriate electrical stimulation of the leg and ankle muscles may improve gait by flexing the foot of persons who have lost or impaired function. There may be additional benefits from FES such as muscle re-education, prevention/retardation of disuse atrophy, increased or maintained range of joint motion and increase in local blood flow.
The ODFS® Pace XL is a medical device and should only be used under medical supervision for the treatment of dropped foot following an upper motor neuron injury.
| Type of Use (Select one or both , as applicable) |
|---|
| ---------------------------------------------------------------- |
X Prescription Use (Part 21 CFR 801 Subpart D)
Over-The-Counter Use (21 CFR 801 Subpart C)
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Image /page/3/Picture/0 description: The image shows a logo with the letters "OML" in white on a blue background. Below the logo, the words "LEADING REHABILITATION" and "THROUGH TECHNOLOGY" are written in blue. The text is centered below the logo. The logo and text are likely for a company or organization that specializes in rehabilitation through technology.
Odstock Medical Limited
National Clinical FES Centre Salisbury District Hospital Salisbury Wilitshire SP2 8BJ UK
Tel +44 (0) 1722 439541 Fax +44 (0) 1722 425263 steven.crook@odstockmedical.com www.odstockmedical.com
510(k) Summary (Traditional format) For the ODFS® Pace XL
Sponsor/Owner/Manufacturer
Odstock Medical Limited Laing Building Salisbury District Hospital Salisbury Wiltshire SP2 8BJ United Kingdom
Odstock Medical Ltd is a Registered Establishment, number: 3005344585
| Contact person: | Steven Crook, Quality and Regulatory Manager |
|---|---|
| Telephone: | 0044 1722 439541 |
| Fax: | 0044 1722 425263 |
| Email: | steven.crook@odstockmedical.com |
30th January 2018 Date prepared
lan Downie (Chairman). Lisa Thomas (Director) · Philip Casson (CEO) · Paul Taylor (Director) Odstock Medical Limited (Company No: 5532620) is part of Salis NHS Foundation Trus
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DEVICE NAME
| Trade/Proprietary Name: | ODFS® Pace XL |
|---|---|
| Common/Usual Name: | Dropped foot stimulator |
| Classification Name: | External Functional Neuromuscular Stimulator (FES)Powered Muscle Stimulator (NMES) |
| Classification No.: | 21 CFR 882.5810 |
| Classification Code: | Class II |
| Product Codes: | GZI and IPF |
Predicate Devices
| Predicate Device | K number | Comment |
|---|---|---|
| ODFS® Pace | K102115 | Odstock Medical Ltd |
| ODFS® III V6.2 | K050991 | Odstock Medical Ltd (transferred fromSalisbury District Hospital) |
Device Description
The ODFS® Pace XL is an external functional neuromuscular stimulator. It consists of a small, body worn, battery powered, single channel stimulator which is triggered by a footswitch worn in the shoe. The footswitch options are:
-
- Shoe insole incorporating wireless transceiver which provides wireless triggering
-
- 'Out of shoe' wireless transceiver with 'in shoe' heel switch. Provides wireless triggering.
- Wired 'in shoe' heel switch for where 1 & 2 are not appropriate or to cover an 3. emergency, e.g. loss of battery power in wireless accessory.
The triggering element and detection is the same across all options and option 3 is common to the ODFS® Pace (predicate device).
Electrical pulses are generated by the device in order to stimulate muscle contractions in the lower limb. (Neuromuscular stimulation) Triggering with a footswitch permits the stimulation to be varied according to the gait of the user. Stimulation produces contraction of the appropriate muscles to cause dorsiflexion of the ankle in individuals who have impaired or absent ability to pick up their foot during walking as a result of a neurological injury. This paralysis affecting the foot is commonly known as 'drop foot' or 'dropped foot'.
The electrical stimulation is delivered via self adhesive skin surface electrodes. The electrodes may be flexibly placed according to the optimum response of the patient but typically are located over the common peroneal nerve as it passes near the head of the fibula. The user may be offered the below knee ODFS® Leg Cuff accessory as aid to locating electrodes repeatedly day to day. An additional option is to mount the ODFS® Pace XL upon the ODFS® Leg Cuff.
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For individuals presenting with weakness and/or spasticity a muscle stimulation exercise program can be delivered by the ODFS® Pace XL. In this case the footswitch trigger is not used and the ODFS® Pace functions as a powered muscle stimulator. A clinician would determine the need for this application which can be enabled from a setup option in the ODFS® Pace XL. (Default is to have the exercise disabled)
Intended Use
The ODFS® Pace XL is intended to provide ankle dorsiflexion in individuals who have a dropped foot as a consequence of upper motor neuron injury. By detecting the swing phase of gait through a foot switch signal, appropriate electrical stimulation of the leg and ankle muscles may improve gait by flexing the foot of persons who have lost or impaired function. There may be additional benefits from FES such as muscle re-education. prevention/retardation of disuse atrophy, increased or maintained range of joint motion and increase in local blood flow.
The ODFS® Pace XL is a medical device and should only be used under medical supervision for the treatment of dropped foot following an upper motor neuron injury.
Technological Characteristics and Substantial Equivalence
The technological characteristics of the ODFS® Pace XL and predicate devices are tabulated below. All the devices are battery powered and deliver electrical stimulation pulses of similar waveform, pulse width and frequency. The ODFS® Pace is a development of the ODFS® III v6.2 and therefore has identical indications for use as an FES device, as does the ODFS® Pace XL. The ODFS® Pace XL has internal software (firmware) version 1.3 whereas the cleared ODFS® Pace has firmware version 1.2. Internal circuitry is unchanged apart from addition of the wireless transceiver expansion circuit.
The footswitch contains a force sensitive resistor within a thin proprietary package. As a wired footswitch this may be located flexibly within the shoe. Generally the position is under the heel. Two wireless footswitch versions are available for the ODFS® Pace XL.
An insole, which has a fixed position for the switch element, fits inside the full length of the shoe. The thickness is of the order of 6mm and a non-functioning equivalent insole is supplied for the other shoe. The thickness of the insole is a limitation which prevents the use in certain shoes.
The second wireless version (OML LINQ™ ) makes use of the thin wired footswitch with a shortened cable. This is connected to a small out of shoe transceiver that can be flexibly located with a clip or retained in a sock. Extensive performance testing was part of the wireless footswitch development to ensure equivalence to the wired version.
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| Feature | ODFS® Pace XL | ODFS® Pace | ODFS® III v6.2 |
|---|---|---|---|
| Firmware | V1.3 | V1.2 | Not applicable |
| Waveform | Biphasic (symmetricaland balancedasymmetrical) | Biphasic (symmetricaland balancedasymmetrical) | Biphasic (symmetricaland balancedasymmetrical) |
| Pulsewidth | $0\mu s$ - $360\mu s$ (±10%)according to patientselection (3.6 $\mu s$ steps) | $0\mu s$ - $360\mu s$ (±10%)according to patientselection (3.6 $\mu s$ steps) | 7 $\mu s$ - $365\mu s$ (±10%)according to patientselection |
| Frequency | Default is 40Hz.20 – 60 Hz in 5Hz stepsavailable | Default is 40Hz.20 – 60 Hz in 5Hz stepsavailable | 40Hz ± 10% |
| Indications for use | The ODFS® Pace XL isintended to provide ankledorsiflexion in individualswho have a dropped footas a consequence of uppermotor neuron injury. Bydetecting the swing phaseof gait through a footswitch signal, appropriateelectrical stimulation ofthe leg and ankle musclesmay improve gait byflexing the foot of personswho have lost or impairedfunction. There may beadditional benefits fromFES such as muscle re-education,prevention/retardation ofdisuse atrophy, increasedor maintained range ofjoint motion and increasein local blood flow.As a NMS/NMES device:relaxation of musclespasm; prevention orretardation of disuseatrophy; increasing localblood circulation; musclere-education; maintainingor increasing range ofmotion. | The ODFS® Pace isintended to provide ankledorsiflexion in individualswho have a dropped footas a consequence of uppermotor neuron injury. Bydetecting the swing phaseof gait through a footswitch signal, appropriateelectrical stimulation ofthe leg and ankle musclesmay improve gait byflexing the foot of personswho have lost or impairedfunction. There may beadditional benefits fromFES such as muscle re-education,prevention/retardation ofdisuse atrophy, increasedor maintained range ofjoint motion and increasein local blood flow.As a NMS/NMES device:relaxation of musclespasm; prevention orretardation of disuseatrophy; increasing localblood circulation; musclere-education; maintainingor increasing range ofmotion. | To provide ankledorsiflexion in individualswho have a dropped footas a consequence of uppermotor neuron injury. Bydetecting the swing phaseof gait through a footswitch signal, appropriateelectrical stimulation ofthe leg and ankle musclesmay improve gait byflexing the foot of personswho have lost or impairedfunction. There may beadditional benefits fromFES such as muscle re-education,prevention/retardation ofdisuse atrophy, increasedor maintained range ofjoint motion and increasein local blood flow. |
| Accessories | Wireless heel switch (2versions), wired heelswitch. Electrode locatorcuff (Leg Cuff) | Heel switch (wired) | Heel switch (wired) |
| Electrode size &shape | 5cm x 5cm | 5cm x 5cm | 5cm x 5cm |
5.6 Technological Characteristics and Substantial Equivalence - Table
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5.7 Performance testing
The ODFS® Pace XL system has been subjected to testing to verify that the device meets its functional and output specifications. Production units pass functional testing of stimulator controls, settings and indicators, stimulus output and timing, footswitch operation, and power consumption.
Parameters measured under the conditions specified in FDA Guidance Document for Powered Muscle Stimulator 510(k)s are included in the ODFS® Pace 510(k) submission. These are identical for the ODFS® Pace XL and reproduced below. (Appendix 1)
Wireless footswitch production models have been tested to functionally perform as reliably and effectively as the wired version.
In addition to functional and operational performance testing the ODFS® Pace XL passed the applicable requirements of the following standards:
- ISO 60601-1-1:2006 Medical Electrical Equipment - General requirements for basic safety and essential performance.
- O ODFS Pace XL is electrically identical to the ODFS Pace in respect of the pulse delivery to the patient. A wireless transceiver circuit is additional and activated when a wireless footswitch accessory is in use.
- o Performance is verified with wired and wireless footswitches.
- . ISO 60601-1-2:2007 Medical Electrical Equipment - General requirements for basic safety and essential performance. Collateral standard: Electromagnetic compatibility - Requirements and tests
- o ODFS Pace XL tested by third party report supplied for inclusion in submission.
- o Wireless accessories are also tested and included in the submitted report.
- I ISO 60601-2-10:2001 Medical electrical equipment. Particular requirements for the safety of nerve and muscle stimulators
- o ODFS Pace XL outputs etc. unchanged from ODFS Pace
Based on the information provided above the ODF5® Pace XL is substantially equivalent to legally marketed predicate devices.
Performance data is included on the next page.
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| Performance data | ODFS® Pace XLModified device | ODFS® PaceMarketed device | ODFS III v6.2Marketed device | |||
|---|---|---|---|---|---|---|
| Feature | ODFS® Pace (cleared device)ODFS® Pace XL (modification) | ODFS III (cleared device) | 510(k) number | Not cleared | K102115 | K050991 |
| Waveform | Biphasic (symmetrical and balancedasymmetrical) | Biphasic (symmetrical and balancedasymmetrical) | Device Name | ODFS® Pace XL droppedfoot stimulator | ODFS® Pace dropped footstimulator | ODFS Dropped footstimulator (ODFS III V6.2) |
| Shape | (Quasi)-rectangular | (Quasi)-rectangular | Manufacturer | Odstock Medical Ltd | Odstock Medical Ltd | Odstock Medical Ltd |
| Maximum OutputVoltage(+/-10%) | 86V peak; 8Vrms @ 500R104V peak; 11.5Vrms @1k125V peak; 14Vrms @ 2K140V peak; 18Vrms @10K | 85V peak; 9Vrms @500R115V peak; 11Vrms @1K130Vpeak;13Vrms@2K150V peak; 14Vrms@10K | Power sources | 9V Alkaline battery(ANSI 1604A)9V LiPo rechargeable(same physical form –removed for charging) | 9V Alkaline battery (ANSI1604A) | 9V Alkaline battery (ANSI1604A) |
| Maximum outputcurrent(+/-10%) | 172mA @ 500R62mA @ 2K14mA @ 10K | 170mA peak:18mArms@500R155mA peak:11mArms@1K65mApeak:6.5mArms@2K15mA peak:1.4mArms@10K | Method of linecurrent isolation | No mains powerconnection. Internal 9Vbattery only | No mains powerconnection. Internal 9Vbattery only | No mains powerconnection. Internal 9Vbattery only |
| Pulse width | 0 - 360 microseconds (+/- 10%) in 3.6microsecond steps | 7 to 360 microseconds, clinicianselectable | Patient leakagecurrent | Normal condition: <10μASingle fault condition:<25μA | Normal condition: <10μASingle fault condition:<25μA | Normal condition: <10μASingle fault condition:<100μA |
| Frequency | 20Hz to 60Hz in 5Hz steps (+/-10%) | 40Hz (+/- 4Hz) | No. of output modes | 2, Symmetrical andBalanced Asymmetrical | 2, Symmetrical andBalanced Asymmetrical | 2, Symmetrical andBalanced Asymmetrical |
| Interferentialmodes:Beat frequencyFor multiphasicwaveforms only | Not Applicable | Not Applicable | Number of outputchannels | 1 | 1 | 1 |
| Symmetricalphases | Yes - symmetrical mode | Yes - symmetrical mode | Synchronous oralternating? | Not applicable - singlechannel device | Not applicable - singlechannel device | Not applicable - singlechannel device |
| Phase duration | 360 (+/- 20) microseconds | 365 (+/- 20) microseconds | Channel isolationmethod | Not applicable - singlechannel device | Not applicable - singlechannel device | Not applicable - singlechannel device |
| Net charge (µC perpulse) | 0µC | 0µC | Regulated current orregulated voltage? | Regulated voltage, sourceresistance effectively =360Ω | Regulated voltage, sourceresistance effectively =360Ω | Regulated voltage, sourceresistance effectively =360Ω |
| Max phase charge | 50μC @ 500R | 50μC @ 500R | Software/Firmware/Microprocessorcontrol? | Yes | Yes | No |
| Maximum currentdensity 1 | 0.9mArms/cm² @ 500R0.6mArms/cm² @ 1K | 0.9mArms/cm² @ 500R0.6mArms/cm² @ 1K | Automatic overloadtrip | No | No | No |
| Maximum powerdensity (mW/cm2) | 3.9mW/cm2 @ 500R3.2mW/cm2 @ 1K | 3.9mW/cm2 @ 500R3.2mW/cm2 @ 1K | Automatic No-Loadtrip | No | No | No |
| Burst Mode (i.e.pulse trains)a. pulses per burstb. Bursts persecondc. Burst duration(seconds)d. Duty Cycle | NA - Continuous pulse train duringswing phase | NA - Continuous pulse train duringswing phase | Automatic shut off | Yes(after 4hr in 'sleep'state) | Yes (after 4hr in 'sleep'state) | No |
| ON Time (seconds) | 0.2 (+/- 0.02) seconds to 6(+/-)seconds as adjusted by clinician | 0.2 (+/- 0.02) seconds to 6(+/-)seconds as adjusted by clinician | Patient overridecontrol | Yes (Pause button) | Yes (Pause button) | Yes (Pause button) |
| OFF Time(seconds) | Varies with gait cadence of patient | Varies with gait cadence of patient | Indicator display | |||
| Additional Features(if applicable) | Pulse train is initiated by heel switch(wired or wireless(XL)) in patient'sshoe. Pulse train is programmed byclinician for fixed duration orterminated after footswitch contact. | Pulse train is initiated by heelswitch(wired) in patient's shoe. Pulsetrain is programmed by clinician forfixed duration or terminated afterfootswitch contact. | On/Off status | Yes – LCD displaysfunction | Yes – LCD displaysfunction | No, audio at on/off,pause/un-pause. Stim Onindicator light |
| Low battery | Yes - via LCD | Yes - via LCD | Yes |
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Substantial equivalence data – basic characteristics.
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| ODFS® Pace XLModified device | ODFS® PaceMarketed device | ODFS III v6.2Marketed device | |
|---|---|---|---|
| Timer range(exercise) | 5 to 100 minutes in 5 minsteps plus unlimited | 5 to 100 minutes in 5 minsteps plus unlimited | Not applicable |
| Compliance withvoluntary standards | YesEN60601-1:2006EN60601-1-2:2007EN60601-2-10:2001 | YesEN60601-1:2006EN60601-1-2:2007EN60601-2-10:2001 | YesEN60601-1EN60601-1-2EN60601-2-10 |
| Compliance with 21CFR 898 | Yes | Yes | Yes |
| Weight | 112g with battery | 112g with battery | 146g with battery |
| Dimensions | 7.2cm x 6.2 cm x 2.6cm | 7.2cm x 6.2 cm x 2.6cm | 6cm (w) x 3cm (h) x11cm(d) |
| Housing material andconstruction | Custom moulded ABSplastic enclosure with clearwindow for LCD | Custom moulded ABSplastic enclosure with clearwindow for LCD | Moulded thermoplasticcase with plastic frontpanel |
| Accessories | In shoe wired footswitch.In shoe wireless footswitch(insole)OrIn shoe footswitch withexternal wirelesstransmitter (OML LinqTM)Electrode cable.Self adhesive skin-surfaceelectrodes.[Option] ODFS® Leg cufffor electrode location anddevice mounting. (alsoapplicable to ODFS® Pace) | In shoe wired footswitch.Electrode cable.Self adhesive skin-surfaceelectrodes. | In shoe wired footswitch.Electrode cable.Self adhesive skin-surfaceelectrodes. |
Output calculations:
FDA Guidance suggests measurements to be made at a load resistance of 500R. Measurements made with 10x probe and digital oscilloscope calibrated against reference 'scope with traceable calibration.
| Under these conditions: | |
|---|---|
| R = 500R | |
| Single pulse measurement: | |
| peak V | 86V, |
| peak instantaneous current, | 172mA |
| therefore RMS voltage (scope measurement function) | 8.0V to 8.5V |
| (depending on how many pulses incorporated into measurement) | |
| RMS current | 16mA to 17mA |
| Max phase charge (taken as peak forward charge) | 48µCoulombs |
| @ approx 320µs |
("integrate" by summing V/500 at each 80us sampling interval in a spreadsheet)
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Image /page/11/Figure/1 description: The figure shows voltage and charge for ODFS Pace at max settings of pulsewidth and current (PP3 battery, 8.5V). The y-axis shows Volts (V) & Charge (µC), and the x-axis shows Time (µs). The figure shows two lines, one for Int µC and one for Voltage. The Int µC line starts at around 40 µC and decreases over time, while the Voltage line starts at around 80 V and decreases to around -40 V before increasing to around 0 V.
Charge balances at approx 6ms from pulse leading edge.
Current density and power density calculations:
Smallest recommended electrodes: 5cm x 5cm square PALS, area = 25cm2
Current density: 172/25 = 6.9mA.cm²2 peak 17/25 ==0.68mA.cm²2 RMS
Power density using P=V2/R:
| peak | $ (86^2/500)/25 = 0.6W\cdot cm^{-2} $ |
|---|---|
| RMS | $ (8.5^2/500)/25 = 5.8mW\cdot cm^{-2} $ |
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§ 882.5810 External functional neuromuscular stimulator.
(a)
Identification. An external functional neuromuscular stimulator is an electrical stimulator that uses external electrodes for stimulating muscles in the leg and ankle of partially paralyzed patients (e.g., after stroke) to provide flexion of the foot and thus improve the patient's gait.(b)
Classification. Class II (performance standards).