PATIENT-ADAPTABLE BIOMEDICAL DEVICES

Beneﬁts and Barriers for Granting Patients More Control

James Andrew Smith and Andr´e Seyfarth

Locomotion Laboratory (Lauﬂabor), Institute for Sports Science, University of Jena, Jena, Germany

Keywords:

Orthosis, prothesis, implanted medical device, insurance, risk, control, adaptability.

Abstract:

End-users of biomedical devices, like many patients undergoing treatment in healthcare systems, often demon-

strate an active interest in their therapy. Patient-speciﬁc customization of medical devices, such as orthoses,

prostheses and implants, is an expensive, time-consuming process. Given how many of these patients are pro-

active and self-motivated it seems appropriate to the authors that these characteristics be harnessed to make

the adaptation of the device to the patient more cost effective. In short, it is proposed that the device end-user –

the patient – play an active role in the tuning and adaptation of the device, especially in the out-patient context.

However, the perceived risk associated with a more pro-active and independent role for the patient is a barrier

to this possibility. These factors are examined and a proposal for a practical approach to a patient-controlled

device optimization process is put forward.

1 INTRODUCTION

The customization of medical devices, such as or-

thoses, prostheses and implants, to the patient is an

expensive, time-consuming process. By reducing fac-

tors which lead to patient noncompliance and by har-

nessing the pro-active and self-motivated nature of

many patients it is likely that the patient-device adap-

tation process can be made more cost effective. The

barriers towards granting greater control to patients in

the updating process will also be examined. Finally,

general strategies that are conducive to the develop-

ment and use of adaptable devices are put forward.

2 WHY PATIENT-ADAPTABLE

DEVICES?

Here, we examine general issues related to treatment

procedures which involve biomedical devices, as well

as reasons why adaptable devices can prove beneﬁcial

to such situations.

In traditional medical practice, physical proximity

between medical personnel and patients is desirable

and often necessary. Often, patients travel to clini-

cal settings to obtain medical services such as check-

ups and monitoring. In other cases, emergency or not,

medical personnel undertake the travelling to visit pa-

tients. In both cases, the associated costs with travel-

ling and visitation, in terms of both time and money,

can be important. In fact, these costs can quickly rise

when the patient normally resides in a remote com-

munity which has insufﬁcient medical resources. Ad-

ditionally, delays associated with transport can have

adverse effects on the treatment of both diagnosed and

undiagnosed conditions.

In addition to distance playing a role on transporta-

tion costs, frequency of visits can also have a signif-

icant effect on costs and effectiveness of treatment.

The customization of medical devices, whether they

be implantable medical devices (IMD) or external

protheses or orthoses, often requires frequent visits

by the patient to a clinical setting. Delays are often

encountered due to complications in both patient and

medical personnel schedules. This can lead to missed

appointments or a reduction in the optimal number

of scheduled visits. Both situations can have adverse

effects on patient treatment regimes. Therefore, solu-

tions which reduce the requirement for physical trans-

portation of either patients or medical personnel, to or

245

Andrew Smith J. and Seyfarth A. (2008).

PATIENT-ADAPTABLE BIOMEDICAL DEVICES - Beneﬁts and Barriers for Granting Patients More Control.

In Proceedings of the First International Conference on Biomedical Electronics and Devices, pages 245-248

DOI: 10.5220/0001056202450248

 SciTePress

from clinical settings are desirable.

Treatment associated with the prosthetic devices al-

most always requires multiple meetings between clin-

ician and patient. When available, telemetry gathered

by the device (either under in- or out-patient condi-

tions) can be provided during these sessions to the

clinician, complementing the traditional discussions

between patient and clinician. To ensure optimal ef-

fect of the device on the patient such information will

be monitored over the course of many sessions. In

the process, changes to the device, or complete re-

placement of the device can occur. The reasons for

this vary from suboptimal tuning of the device to a

breakdown of the device, as well as to changes in the

patients condition or environment conditions that the

patient encounters.

Changes in the aforementioned conditions can hap-

pen outside the clinical setting. In the event of such

changes it is advisable that appropriate actions be

taken as quickly as possible. This is especially im-

portant where the change in condition has an adverse

effect that could endanger the patient. Even in cases

where the change does not endanger the patient, but

leads to discomfort or diminished conﬁdence in the

device, it is advisable that the problem be addressed

relatively quickly. Therefore, solutions that ensure a

high frequency of monitoring and updating are desir-

able. However, updating or adaptation of the device

does not necessarily need to be done by a clinician or

therapist. In cases of misadjustment of a prosthetic

leg, the resulting skin ulcers can dramatically reduce

a patient’s ability to use the prosthetic device, with a

consequent reduction or total loss of mobility (Brandt,

2004). The ability of a patient to actively modify the

device without the need for clinical supervision can

be beneﬁcial when such services are unavailable or

impractical. This is apparent in the treatment of pain

through the use of patient-adjustable bracing (Dra-

ganich et al., 2006) or in cosmetic and comfort ad-

justments with respect to heel height in foot prosthet-

ics. In these cases, it is far more practical to allow the

patient to make adaptations without direct clinical su-

pervision. This is especially relevant since, as will be

discussed in the next section, treatments that reduce

ambulation ability can also become more vulnerable

to patient non-compliance (Aldridge et al., 2002).

The goal of the clinical visitations is often related

to monitoring a patients general health and the sta-

tus of any diagnosed condition. In the cases that the

patient has been previously prescribed a medical de-

vice related to a diagnosed condition the health ser-

vice provider often uses the clinical visitation time to

also monitor the condition of the medical device. Up-

dates to the device may also be performed during this

time, as the health care provider is often an expert in

the adjustment of such devices. Outside of the clini-

cal setting, prior-art (Bardy, 2003) demonstrates that

such device monitoring and update work can also be

done in an autonomous and remote fashion. While

these devices are not necessarily directly adaptable

by the patient, they do contain the functionality for

adaptability outside the clinical setting. A number

of patents (Dufﬁn et al., 1995) (Linberg, 1999) have

been assigned for such remote expert system updata-

bility , including at least one which permits the patient

to input activity and environmental conditions for op-

timal implant performance (Boies et al., 2000).

Although customizable and updatable systems

(remotely or locally) can have both therapeutic and

cost beneﬁts, there are barriers to their implementa-

tion. The next section explores some of these issues.

3 BARRIERS TO

PATIENT-ADAPTABLE

DEVICES

The development and use of patient-adaptable

biomedical devices shares many of the same barriers

encountered in by any biomedical device.

First, regardless of the intention of the clinician or

manufacturer, without patient compliance the device

will be ineffective. A patient’s existing living con-

ditions or environment may not be compatible with

the proposed device and treatment strategy (Pinzur

et al., 1992). Likewise, psychological or physiologi-

cal factors may preclude usage of the device. Without

proper counselling and education, cognitive, motiva-

tional and emotional barriers can also be barriers to

effective use of a given medical device (Pinzur et al.,

1992).

The possibility of critical failure of a device, espe-

cially in cases where such failures can place people in

danger, must be weighed by manufacturers, end-users

and prescribers of such devices. This applies to many

ﬁelds, not just the biomedical ﬁeld.

In the case of lower extremity prosthetic or or-

thotic devices the possibility of falling is of particu-

lar concern, as such falls can lead to serious injury

or death. With some justiﬁcation, the fear that such

an event can occur is “pervasive” (Miller et al., 2001)

within the amputee community. This leads to partic-

ular lines of action by both device manufacturers and

patients to reduce the possibility of fall.

Actual falls, as well as the fear of falling can have

repercussions on mobility and social activities. The

psychological effects related to the fear can lead to

BIODEVICES 2008 - International Conference on Biomedical Electronics and Devices

246

self-imposed restrictions which, in turn, lead to de-

terioration in physiological conditions (Miller et al.,

2001). Given that this downward spiral runs counter

to the original intentions when equipping an amputee

with a prosthetic leg, it is important that the possibil-

ity of fall and the related fear be addressed as seri-

ously and openly as possible.

The evaluation of risk, either by a patient or a

device manufacturer can have serious ramiﬁcations,

both positive and negative. During the risk evaluation

process it is important to remember that risk determi-

nation should not only be founded on the device itself

but also on the proposed use of the device. This re-

quires weighing the risk against the beneﬁcial uses of

the device. If the addition of a feature promotes the

use of the device, either through increased user con-

venience or conﬁdence, the short-term possibility of

increased user risk for falling may be offset by less-

ened possibility of longer-term psychological conse-

quences, as outlined above.

4 THE WAY FORWARD

Devices which maximize user comfort, convenience

and conﬁdence are most likely to be successful in pa-

tient treatment. In cases such as treatment of Char-

cot’s Foot, total contact casting is the “gold standard”

for treatment, patient non-compliance plays a roll in

its relatively high failure rate. The reduced mobility

that results from such treatment can be so deleteri-

ous, and thereby resulting in patient non-compliance,

that alternative forms of treatment have been devel-

oped that allow the patient some form of ambulation

(Aldridge et al., 2002). The device should, if at all

possible, usable within the patient’s existing lifestyle,

which in many cases requires a signiﬁcant degree of

mobility.

The development of patient-adaptable devices is

an effective avenue for many forms of treatment.

These are especially effective when the patient feels

an immediate and persistent self-motivation with re-

spect to the device. One such example, that of patient-

adjustable valgus-producing knee braces, can have

immediate, short-term pain- and stiffness-relief bene-

ﬁts for patients (Draganich et al., 2006). Devices such

as the Ossur Elation and Proprio feet allow the am-

putee to adjust heel height, thus permitting the use of

high-heel shoes, for instance. While the use of these

types of shoes may place the amputee at greater risk

for fall, the long-term psychological consequences of

this convenience would seem to outweigh the short-

term physical risk. Of course, to maximize the poten-

tial of these adjustable devices, the adjustment mech-

anisms must be as convenient as possible.

Making the device convenient to use is not sufﬁcient,

however. While its use and its adjustment mecha-

nisms (if any) may seem intuitive to an expert, this

cannot be assumed to be the case with the patient.

Given that non-compliance can, in many cases, be

traced to misunderstanding by the patient (Smith and

Smith, 1994), it is important that special attention be

paid to patient education. The practitioner should be

especially aware of the fact that relevant documenta-

tion often given to the patient is written in a manner

which leads to misunderstandings (Smith and Smith,

1994). Therefore, patient education – which is inti-

mately tied to the notion of informed patient consent

– should be tailored to the comprehension level of

each patient in order to reduce the possibility of pa-

tient non-compliance based on misunderstanding.

Simply allowing the patient to make active changes

to the device, as outlined above, is not the only strat-

egy for involving the patient in the therapy “feedback

loop”. Within the clinical context (i.e. under the di-

rection of a trained therapist or clinician), a device

that adapts to the patient in a semi-autonomous fash-

ion has enormous potential. The device can take a co-

operative approach to the patient interface and does

not necessarily require direct or conscious adaptation

strategies by the patient. In fact, “human-centred

robotic” gait trainers are currently being developed

which combine robotic mechanisms that adapt their

movement to the muscular efforts of the patient, as

well as the patient’s passive mechanical properties

(Riener et al., 2006). These patient-adaptable de-

vices still require the expertise of therapists to develop

strategies for therapy, but promise to increase patient

comfort and therapy effectiveness.

From a manufacturer’s point of view, the calculation

of acceptable risk for device feature sets must be con-

ducted. This begins with setting a threshold for tol-

erance of risk, followed by the determination of a de-

vice’s intended use and required feature set. Next,

the feature-by-feature risk is estimated by examining

the probability of a given event and the consequent

level of operator or patient harm. Features which ap-

proach the tolerance thresholdwill requirespecial jus-

tiﬁcation with respect to physiological or psychologi-

cal beneﬁts, while those which exceed it must be dis-

carded. Next, testing is conducted to verify the as-

sumptions on which the risk levels are based, alarm

and compensatory devices are implemented. Finally,

the cycle is repeated until veriﬁcations produce re-

sults which match the declared risk tolerance thresh-

old. This process is a straight-forward one that results

from an attempt to adhere to risk management strate-

gies that conform to international standards such as

PATIENT-ADAPTABLE BIOMEDICAL DEVICES - Benefits and Barriers for Granting Patients More Control

247

ISO 14971 and IEC 60601-1; these standards are, in

turn, a result of regulatory requirements by national

and international agencies.

Finally, the device must be made affordable to

the patient in absolute terms, as well as relative to

possible alternatives which may or may not include

adjustable functionality. Where alternatives include

immobilization and long-term hospitalization, it is

critical that comparisons be made with respect to

the additional costs related to diminished mobility.

Given the role of third-party payees such as govern-

ment agencies or private insurance companies, the

cost of such devices must also be justiﬁable to them.

This is especially important in cases where utiliza-

tion management and technology assessment studies

result in limited outcomes due to small sample size

or absence or randomized controlled trials in peer-

reviewed journals (Fish, 2006). Therefore, rigourous

and independentcase-by-case studies need to be made

to verify the potential short-term (e.g. adjustable

valgus-producing knee unloader braces) and longer-

term (e.g. the adjustable heel height feet) beneﬁts of

patient-adjustable biomedical devices.

5 CONCLUSIONS

The beneﬁts for adaptable prosthetic devices has been

examined, as have the barriers for both these and

biomedical devices in general. General strategies for

implementation have been examined, as well. In the

end it is important for trained personnel to make a

holistic evaluation of the patient, taking into account

patient lifestyle issues, physiological and psychologi-

cal factors, costs, requirements by third-party payees,

etc. Engaging the patient through education and good

design practice are key to the development and use of

these types of devices.

ACKNOWLEDGEMENTS

The authors would like to thank Donald Smith, Cathy

Huth and Michelle Huth for their feedback. As well,

the authors would like to thank the following people

for their valuable input: Dr. Robert Farley at the Scot-

tish ExecutiveHealth Directorate, Drs. Stefan Bircher

and Burkhard Zimmerman at Hocoma AG Medical

Engineering, Roland Auberger at Otto Bock Health

Care, and Knut Lechler at Ossur R&D.

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