AMI Construction in Lower Extremity

Amputees: Clinical Outcomes to DateMatthew J. Carty, MD

Staff Surgeon, Division of Plastic Surgery

Brigham and Women’s Hospital

Associate Professor of Surgery

Harvard Medical School

I have no disclosures or conflicts of interest.

BWH

USNMCSD

Matthew CartySimon TalbotEric BlumanGeorge DyerAnthony AmatoStacy SmithLuis BeltranSarah WelchKendall ClitesLori Berger

Craig Salt

MIT

WRNMMC

UCSF

UMich

NWUMC

Hugh HerrShriya SrinivasanRickard Branemark

Jason SouzaKyle PotterJonathan Forsberg

Richard O’Donnell

Paul CedernaTyler Clites

Greg Dumanian

Funding support via Stepping Strong Innovator Fund, DoD/PRORP, DARPA

Acknowledgments

AMI Architecture Models

“Native”“Regenerativ

e”

8

Patient Summary to Date

Total Patients

Gender Split (M,F)

Age (Years)

BMI

ALOS (Days)

Operative Time (Min)

• 16 BKA, 3 AKA

• 47% Male, 53% Female

• 40.1

• 26.4

• 5.4 BKA, 9.7 AKA

• 339 BKA, 531 AKA

Trauma65%

Congenital15%

Iatrogenic15%

Thermal5%

y = -0.5882x + 343.88R² = 0.0037

0

50

100

150

200

250

300

350

400

450

500

710 393 470 114 639 423 745 424 986 205 816 876 866 441 169 143

OP

ERA

TIV

E TI

ME

(MIN

)

SUBJECT ID

Ewing Amputation (Modified BKA) Operative

Times(n=16 patients)

Dissection82 (27%)

Osteotomy10 (3%)

Tunnel Harvest31 (10%)

AMI Construction91 (30%)

Bead Placement30 (10%)

RPNI Construction20 (7%)

Tailoring26 (9%)

Closure13 (4%)

Ewing Amputation (Modified BKA) Operative Time by Operative Component

(in minutes)

y = -137x + 853R² = 0.9508

0

100

200

300

400

500

600

700

800

380 947 227

OP

ERA

TIV

E TI

ME

(MIN

)

SUBJECT ID

Modified AKA Operative Times(n=3 patients)

Reported average for standard BKA

Source: Sanders et al, 2011

0%

20%

40%

60%

80%

100%

120%

A B C D E F G H I Mean

Tibial Plateau Circumference Mid-Tibial Circumference

Limb Circumference Preservation

Mean Time to

Full Narcotic Wean

Residual Limb Pain

Phantom Limb Pain

Phantom

Perception

• 77 days (range 7-181 days)

• Only reported in 3 patients who

did not undergo full RPNI

construction

• None

• “Functional” phantom

perception reported

consistently across all patients

Pain/Perception Related Outcomes

Mobility

Self Care

Usual Activities

Pain-Discomfort

Anxiety/Depression

Health Scale

0.001

0.29

0.003

<0.001

0.2

0.0004

• Significant improvement

• No effect

• Significant improvement

• Significant improvement

• No effect

• Significant improvement

SUBJECT t-TEST p

VALUE

CONCLUSION

EQ-5D Pre- vs. Post-operative Mean Survey Results

y = 7.787x + 28.171R² = 0.9453

0

10

20

30

40

50

60

70

80

90

100

BASELINE 6WEEKS 3MONTHS 6MONTHS 9MONTHS 1 YEAR

PER

CEN

T O

F M

AX

IMA

L FU

NC

TIO

N

TIMELINE

Mean LEFS Scores Over Time

PROMIS-57 Pre- vs. Post-operative Mean Survey Results

Physical

Function

Anxiety

Depression

Fatigue

Sleep

Social Roles

and

Activities

Pain

Interference

Pain Intensity

0.001

0.0069

0.002

0.0003

0.055

<0.0001

<0.0001

0.0002

29.5%

-14.0%

-8.5%

-27.25%

-11.5%

33.5%

-41.5%

-9.4%

SUBJECT t-TEST p

VALUE

%Δ

• Superficial cellulitis over constructs requiring short term oral or topical antibiotics (33%)

• Minor wound healing issues (33%)

• Major wound healing requiring operative intervention (22%)

Complications

Emerging Paradigm of Management

PROSTHESIS RECONSTRUCTIONVS&

Ewing Amputation Standard Amputation

Ewing Amputation Standard Amputation

OTHER LIMB MODELS

OSSEO-INTEGRATION

REVISIONOPTIONS

Parallel Investigations

33

AMPUTATION

SURGICAL

FAILURE

LIMB

SALVAGE

Philosophical Approach to Amputation

INCREASING RECONSTRUCTIVE SOPHISTICATION

Critical tenet of emerging notion of

functional limb restoration