BION Packaging

Mechanical Loading of Rigid Intramuscular Implants

Gerald E. Loeb, Raymond A. Peck, Jesse Singh, Young-Ho Kim+, Sudeep Deshpande and Lucinda L. Baker*

Alfred Mann Institute for Biomedical Engineering

*Dept. of Biokinesiology and Physical Therapy

University of Southern California +Dept. of Biomedical Engineering, Yonsei University, Korea

BION Implants for

Neuromuscular

Stimulation

16mm

2mm

Ir electrode

hermetic

glass

capsule

Ta capacitor

electrode

12 ga.

insertion tool

BION1 Clinical Trials Underway Study PATIENTS BIONs

Enrolled Withdrew Implanted Implanted Out of spec Explanted

Acute shoulder subluxation

Kingston, Canada 14 0 9 19 0 0

Knee osteoarthritis

Milan, Italy

5 0 5 10 0 1

Chronic shoulder subluxation

Downey, CA 14 0 10 22 8 0

Hand contractures

Downey, CA

16 1 10 25 7 0

Foot drop

Edmonton, Canada 1 0 1 4 1 0

Hand retraining

Los Angeles, CA

new IDE

Pressure ulcer prevention

Downey, CA

new IDE

TOTALS to date 50 1 35 80 16 1

4 fractured cases, all following long-term, intense exercise, no trauma

As implanted:

Initial x-ray:

5 mo. x-ray:

Wrist Extended

Wrist Flexed

◄hand

BION Capsule Strength

S2mmdiam.

2mmx8mmx0.3N/mm2=5Nmax

BION Impact Tests 10N

1N

1N

20ms

1 kg from 360 mmv = 2.66 m/s

E = 3.53 J

Loadcell

Center

Offset

2.20 N

1.24 N

1.21 N

0.62 N

12.5 mm

1.51 N 3.80 N

2.15 N0.26 N

25 mm

HIGH SPEED IMPACT CONDITIONS LOW SPEED IMPACT CONDITIONS

2.5 mm

10 mm

10 mm

10 mm

skin

muscle

v

vh

hmm

h=1.44 m

m=1 kg

v=5.32 m/s

E=14.13 J

h=0.36 m

m=0.5 kg

v=2.66 m/s

E=1.77 J

G=1.33 N s.G=5.32 N s.

Stress Repetitions

• ~0.8N bend 2 bend Fx @ 30kc

• ~1.2N bend 5 bend Fx @ 500c

• 7 bend + 0.1N shear Fx @ 30c

Requirement: 2h/d x 84d ÷ 5s/c = 121kc

Remediation: >4000kc (to date)

Fragmented glass

bead cracks

Loading Modes in vivo

Connective tissue

Muscle

Tendon

Tendon

Ir electrode

Ta

Electrode

Glass

Capsule


Case 1&2 Case 3 Case 4

Connective tissue

Muscle

Tendon

Tendon

Tendon



Tendon

Muscle

Tendon

Ir electrode

Ta

Electrode

Glass

Capsule



Muscle

Tendon Ir electrode

Ta

Electrode

Glass

Capsule

y

x

L

l

c

),( dL

),( c01A

2AO

= -F = shear reaction force

between glass capsule and

electrode

y

x

L

c

1A

2AO

c

l

Uniformly Distributed Load 30N/cm2

-FA

L

Connective

Tissue

-FB

Case 1:

1.8N

Case 2:

?>1.8N

Case 3: 3.6N

(each end)

Redesign & Remediation

A

B

Fuse glass bead to Ta stem & sintered electrode

using vacuum furnace and carbon tooling

BION1 Hermetic Package Assembly

Nd-YAG laser welds:

2) PtIr Washer to Ta stem

4) Spring to Ta tube

7) Ta tube seal/cut & Ir Washer

CO2 laser welds:

3) Glass bead to Ta tube

5) Glass beads to capillary

Vacuum furnace seal:

1) Glass bead to Ta Electrode

6) He leak test

1)

2)

5)

4) 3)

5)

7)

ASIC

Capacitor

Wire bonds

Substrate

Ferrites Coil

Repetitive Loading Pattern

Applied Force

Glass capsule

Ta

Electrode

Ir

electrode

Saline @ 37C

>4,000,000 cycles @ 8N without failure

30 30

MPa

0

Clinical Status

Revised design now completing long-term validation testing

Revised IDE approved by FDA and IRBs

Clinical implantations resume in October

Risk Factors for Implanted Stimulators

Percutaneous implantation can result in unexpected mechanical configurations.

Chronic, strong electrical stimulation strengthens muscles.

Long term use produces large numbers of stress cycles.

Failures are accelerated synergistically by stress x repetitions x temperature x water

BION1 Hermetic Package Assembly

Nd-YAG laser welds:

2) PtIr Washer to Ta stem

4) Spring to Ta tube

7) Ta tube seal/cut & Ir Washer

CO2 laser welds:

3) Glass bead to Ta tube

5) Glass beads to capillary

Vacuum furnace seal:

1) Glass bead to Ta Electrode

6) He leak test

1)

2)

5)

4) 3)

5)

7)

ASIC

Capacitor

Wire bonds

Substrate

Ferrites Coil

BION Packaging Work Station

Y A G H e a d s

C O 2 L e n s

M i r r o r A s s e m b l y

V a c u u m

C h u c k

V B l o c k

X Y Z

T r a n s l a t i o n

S t a g e s

S y n c h r o n o u s

D r i v e

C O 2 B E A M

Y A G B E A M

Y A G H e a d s

C O 2 L e n s

M i r r o r A s s e m b l y

V a c u u m

C h u c k

V B l o c k

X Y Z

T r a n s l a t i o n

S t a g e s

S y n c h r o n o u s

D r i v e

C O 2 B E A M

Y A G B E A M

Electrochemistry of the BION

Capacitor Electrodes

BION1 Design Features

• Injectable through 12 ga. needle

• Fail-safe capacitive electrodes

– Anodized, sintered Ta

– Activated Ir

• Glass hermetic package

• Ceramic uPWB

• Water getter

• 2 MHz AM carrier

Hermeticity Test Requirement

LEAK

RATE

cc atm/s

VOLUME

cc

LIFE

TIME

s

BIONTM

1day 1mo. 1yr.

50% vol., 6% water vapor10% vol. getter

30yr.10yr.

mil

spec

typ.

prod.

max.

sens.

implantable

defibrillator

CLARIONTM

cochlear

implant

cardiac

pacemaker

102

101

100

10-1 10

-2

10-9

10-4

10-5

10-3

10-3

10-6

10-7

10-8

10-2

105

106

107

108

109

1010

10-11

10-12

10-13

10-10

trapped He detectorconventional bubble test

high pressure bomb - 100 atm

He mass spectrometer

Moisture Getter

• Natrasorb 900®: silica gel in machinable polymer

• Cylinder: 1.5mm od x 0.5mm id x 1mm = 1.1mg

• Slides over spring welded to tubular feedthrough

• Vacuum baked at 230C

• Potential water vapor absorption = 250 mm3

1.1mg • 18% • mole/18g • 22.4x106mm3/mole

• Capsule water vapor at dew point = 0.64 mm3

• Apparent package volume = 390X

• He leak testing sensitivity = 1 x 10-10 cc atm/s

• Minimum lifetime = 80 years

BION2 Assembly Sequence

To Helium Leak

Detector

A

D

C

E

A Wrist Extended

B Wrist Flexed

◄hand

Capsule Failure due to Repetitive Stress

peg (cannula handle peg)

cannula

cannula handle (inner handle)

probe handle (outer handle)

BIT v.5.4 (BIONTM Insertion Tool)

probe tip

BIONTM

rotate peg along track to release BIONTM

RF-Powered BION

BION Packaging

Documents

Transcript of BION Packaging