Independent, source-linked catalog sheet. Not a manufacturer-issued datasheet, regulatory decision or instructions for clinical use. Human evidence does not establish approval. Source-specific restrictions, conflicts and missing specifications are retained below.
Design and sensory-study records
CWRU/Ardiem spiral cuff
These sheets cover the same self-sizing cuff design family. The standard four-contact photograph appears once; the sensory study is a deployment record, not a second cuff architecture. The ITIS 33-contact prototype has its own catalog entry.
CWRU self-sizing spiral nerve cuff (upper-limb sensory stimulation research deployments)
This is a sensory-deployment record of the CWRU/Ardiem self-sizing design family, not a second spiral-cuff architecture. The standard reference photograph belongs to the family sheet.
Every field follows the shared implant-device template. Values belong to a named configuration or study; not reported means the reviewed sources do not establish the value. Family-wide and deployment-specific evidence are kept separate.
Identity
Field
Value and source scope
Device
CWRU self-sizing spiral cuff, human research configurations
Manufacturer
CWRU design; Tan 2015 implanted components manufactured by Ardiem Medical. Not one universal vendor SKU
Interface class
Extraneural peripheral nerve stimulation cuff
Origin
Naples, Mortimer, Scheiner and Sweeney design; cited in Christie 2017
First demonstrated
1988 design publication cited in Christie 2017; earliest implant date not established here
First human implant
Human implants since 2005 in Christie 2017 cohort; not claimed as first-ever human implantation
Species studied
Human in Christie 2017 and Tan 2015; earlier animal evidence cited, not re-audited here
Regulatory status
Research implants; Tan 2015 reports FDA Investigational Device Exemption, not commercial approval
One to four independent stimulation contacts per cuff in Christie 2017; monopolar versions connect four contacts in series
Pitch
Configuration dependent; no universal pitch
Electrode lengths
Not applicable to penetrating shanks; cuff axial length not reported in audited descriptions
Shank width and thickness
Not applicable; cuff diameter selected intraoperatively from 2-10 mm inventory, Christie 2017
Tip and exposed site geometry
Configuration dependent; Tan 2015 radial spiral: four contacts, 4 mm cuff diameter; exposed area not reported
Contact coating
Insulation
Self-curling polymer sheath, Christie 2017; composition and thickness not established in audited Methods
Insertion method
Surgical nerve exposure and wrapping around nerve, without epineurial penetration
Anchoring and fixation
Self-sizing wrap can secure without sutures, Christie 2017; redundant lead length matters for strain relief
Electrode and channel physics
Field
Value and source scope
Exposed site area
Electrode material
Impedance (with measurement frequency)
Tan 2015 radial spiral in subject 1: 2.91 ± 0.22 kΩ. Derived from voltage drop with 0.3 mA, 50 µs pulses at 20/100 Hz, not 1 kHz spectroscopy
Noise floor or SNR
Recording modality
Recording capability not reported in reviewed deployments; these are stimulation studies
Sampling rate
Not applicable to passive cuff stimulation; controller acquisition is system-specific
Stimulation capability
Constant-current charge-balanced biphasic stimulation in Christie 2017. IST supports 1-255 µs and 0.1-20 mA, but study generally limits current to 2.1 mA or less; not a cuff safety rating
Charge injection limit
Not given as material injection limit; study stimulus settings are not a charge-injection limit
Reference and ground
Christie 2017: titanium implanted stimulator case is common return. Tan 2015 uses external UECU and percutaneous leads; do not conflate assemblies
Tissue interface and bioresponse
Field
Value and source scope
Target tissue
Extraneural peripheral nerve surface
Insertion trauma and BBB disruption
BBB: not applicable; cuff does not breach epineurium, Christie 2017. Quantitative surgical nerve injury not reported
Vascular disruption risk
Quantitative risk not reported; proper fit and accommodation of nerve size are design concerns, not a validated low-risk rating
Micromotion sensitivity
Lead tension implicated in one cuff pulling off thoracodorsal nerve, Christie 2017
Gliosis and encapsulation
Peripheral nerve, not CNS gliosis; quantitative fibrosis histology not reported in reviewed human studies
Neuron loss near sites
Foreign-body response mitigation
Self-sizing construction accommodates differing nerve sizes; no quantitative mitigation efficacy established
Typical failure modes
Christie 2017: one cuff pulled off nerve, attributed to possible lead tension; one contact in active cohort nonfunctional
System architecture
Field
Value and source scope
Onboard electronics
None in cuff; separate implanted stimulator-telemeter in Christie 2017
Data path
Cuff lead to implanted IST in Christie 2017; Tan 2015 sensory system instead uses percutaneous leads to external UECU
Telemetry bandwidth
Sampling rate
Configuration dependent; not an electrode-only specification
Power
Christie 2017 IST receives external inductive radiofrequency power/control. Tan 2015 uses external stimulator
Thermal management
Packaging and hermeticity
Passive cuff plus separately packaged stimulator; hermetic qualification not reported in audited descriptions
MRI compatibility
Surgical complexity
Peripheral nerve exposure, cuff sizing and lead routing; controller placement depends on system
Output connectors
Tan 2015: spring-sleeve connectors to open-helix percutaneous leads. Christie IST connector dimensions not reported
Performance envelope
Field
Value and source scope
Acute yield
Not given as uniform acute yield across configurations
Chronic yield
Christie 2017: 44 of 45 contacts functional in eight actively participating recipients; not 44/45 of all implanted contacts
Stability over time
Christie 2017: most thresholds stable; 20/27 monitored contacts increased by less than 5 nC/year
Longevity
Christie 2017 reports functional cuffs 2-11 years implanted; mean time since implant 6.7 ± 3.1 years. Not maximum rated lifetime
Revision and explant experience
Christie 2017: one IST explanted for perioperative infection after three months; cuffs remained implanted and operational at testing but inaccessible afterward
Adverse events
Christie 2017: one cuff pulled off nerve; perioperative infection involved IST, not cuffs. Tan 2015: no infection in reviewed period
Notable demonstrations
Femoral cuffs produced knee-extension moment sufficient for standing after 2-4.5 years; sensory feedback via radial spiral in one Tan 2015 participant
Clinical and preclinical evidence
Field
Value and source scope
Human subjects
Christie 2017: 14 people, 50 cuffs on 10 nerves; 13 SCI and one transradial amputee. Tan 2015 spiral is only the radial cuff in subject 1, not all cuffs in its two-person study
Preclinical cohort
Follow-up duration
Christie: up to 11 years implanted, thresholds measured over up to 10.4 years. Tan: mixed cuff follow-up 1-2 years; do not assign all FINE outcomes to spiral
Indications
SCI motor restoration and limb-loss sensory restoration research
Trials and registries
Tan 2015 FDA IDE study; registry number not reported in audited Methods
Primary outcomes
Charge thresholds, recruitment curves, motor-unit overlap and sensory percept stability
Key limitations
Selected active participants, heterogeneous systems and nerves; contact-level denominator differs from total implanted cuffs
Engineering tradeoffs
Field
Value and source scope
Strengths
Human multi-year stimulation evidence without penetrating nerve fascicles
Limitations
Surface contacts preferentially access nearby fascicles; deep populations harder to isolate, Christie 2017
Scaling constraints
Available nerve circumference, independently wired contacts and controller channels; no numerical ceiling established
Related research · Related rat sciatic-cuff experiment, not this human sensory-cuff deployment. Recording and stimulating cuffs are distinct.
Evoked nerve and muscle recordings
Nerve cuff · ENG & EMG
Measured data
Compare single recorded events at three stimulation amplitudes, retaining the stimulus artifact, cuff ENG and muscle EMG. Amplitude units are unresolved in the source metadata and remain source units.