A CLINICAL AND ECONOMIC ASSESSMENT
OF A MYOELECTRIC ORTHOSIS FOR
BRACHIAL PLEXUS INJURY
Background
Brachial plexus injuries (BPI) can occur as a result of shoulder trauma, tumors, or inflammation. The brachial plexus
is made up of spinal nerves that are part of the peripheral
nervous system. It includes sensory and motor nerves that
innervate the upper limbs. The brachial plexus includes the
last 4 cervical nerves (C5-C8) and the 1st thoracic nerve (T1).
Each of those nerves splits into smaller trunks, divisions,
and cords. The lateral cord includes the musculocutaneous
nerve and lateral branch of the median nerve. The medial
cord includes the medial branch of the median nerve and
the ulnar nerve. The posterior cord includes the axillary
nerve and radial nerve. Injuries to the brachial plexus result
from excessive stretching or tearing of the C5-T1 nerve fibers and can be classified as either traumatic or obstetric.1
Obstetric injuries may occur from mechanical injury involving shoulder dystocia during difficult childbirth. Traumatic injury may arise from several causes including sports,
high-velocity motor vehicle accidents, especially involving
motorcycles. Traumatic BPI most commonly affects the supraclavicular zone.2
Traumatic Brachial Plexus Injury Incidence
Vehicle crashes are the leading cause of BPI.3 Annual data on such accidents provides a method for estimating TBPI incidence.
Table 1.
Vehicle Type
Automobile/Truck
Motorcycle
Non-Fatal Accidents4,5
% Resulting in TBPI3
Annual TBPI
2.07M
0.67%
13,869
88K
4.20%
3,696
17,565
Depending upon the severity of the BPI different treatment pathways may be followed. Although in the 1990s it was considered prudent to
wait five or six months before indicating surgery, improvements in imaging examinations sometimes change wait times. Today, depending
on the severity of the injury, there is a tendency to indicate surgery earlier rather than later since more is now known about earlier nerve
regeneration.6 For those that undergo surgery (procedures include neurolysis, nerve grafting and neurotization), approximately 45% will
regain function sufficient enough to perform activities of daily living (ADL) and return to work.7 This results in an annual incidence of approximately 9,700 individuals who remain disabled due to the injury.
Treatment Options for Surgical Failure with BPI
For those individuals who experience little to no recovery post surgery, upper limb hemiparesis which can include the elbow, wrist and hand
has several treatment pathways.
Rehabilitation
Rehabilitation programs that attempt to range the affected arm and possibly reduce muscle atrophy are typically used. They require compliance by the patient and the ability to maintain insurance coverage for therapy. Long term rehabilitation and therapy for the upper limb can
become costly, time consuming and often difficult to maintain due to slow recovery and patient frustration.
Amputation with Prosthetic
Transhumeral amputation plus shoulder fusion with prosthesis is sometimes considered for complete and untreatable plexus lesions, although many clinicians have noted that a significant percentage discard their prostheses over time.3 Advances in available prosthetic componentry have multiplied the options available for amputees with BPI and have increased the percentage of patients who can actuate an
active prosthesis. Upper extremity BPI prosthetics arms can be complex to control due to requirements of a series of fine muscle movements.
Flail Arm Static Orthosis
In view of the substantial percentage of BPI amputees who reject prosthetic devices, immobilization of the flail arm is preferred using splints
or non-movable orthoses. While management of the flail arm is achieved, muscle atrophy and other comorbidities often result from lack of
use.
Myoelectric orthoses
A commercially available myoelectric elbow-wrist-hand orthosis (myoelectric EWHO) is the MyoPro Motion-G from Myomo, Inc. The device
is custom fabricated and is designed to be used in the home to increase functional ADLs by providing the user with intention driven, myoelectric elbow and hand movement and manual wrist articulation. Not all hemiparetic individuals with brachial plexus injury are candidates.
The general inclusion criteria are:
• Inability to use affected arm(s) functionally, inability to open/close hand
• Minimum of trace MMT (1/5) in Biceps and/or Triceps (i.e. good volitional EMG signal)
• Full passive range of motion in elbow, wrist and fingers
• Intact cognition (mini-mental score > 20)
• Good caregiver/family support
• Highly motivated
• Active shoulder flexion of at least 30-40 degrees or shoulder abduction of at least 20 degree
Returning to Work
Cooking
The MyoPro Myoelectric EWHO can help users perform ADLs and promote independence.
Clinical Considerations
Treatment approaches and outcomes for BPI with disability can be qualitatively assessed across several dimensions including increased
independence, a return to work, the ability to perform ADLs, preventing overuse of unaffected side and a reduction in muscle atrophy.
These are summarized in Table 2.
Table 2.
Treatment
Increase
Independence
Return to Work
Perform ADLs
Preventing Overuse of
Unaffected Side
Reduce
Muscle Atrophy
TOTAL
SCORE
Rehabilitation
•
•
•
•
•
9
Amputation w/Prostheses
•
•
•
•
•
15
Static Orthosis
•
•
•
•
•
9
Myoelectric EWHO
•
•
•
•
•
23
• Highly effective (5)
Scale:
• Moderately effective (3)
• Not effective (1)
A myoelectric EWHO can be an effective treatment pathway since the device will support the weakened arm and range the elbow, wrist
and hand through user intention. Clinically, this enables the performance of goal driven ADLs in the therapy clinic and home and may
help to avoid overuse of the unaffected arm while reducing muscle atrophy. This device may also contribute to overall well being by
enabling the user to function more independently with the ability to perform functional tasks related to feeding, dressing and hygiene.
By providing a numerical value to rate each of the three levels of effectiveness it is possible to quantify an overall clinical value for each
treatment type.
Economic Considerations
Brachial plexus injury brings with it non-trivial costs associated with initial treatment and post injury care. For those injuries that require
surgical intervention including neurolysis, nerve grafting and neurotization, the total cost (including hospital fees) can range from $20,000
– 40,000 depending upon the complexity of the repair.8 Published rehabilitation cost data for stroke can be used as a proxy for BPI as
the services provided have overlapping similarities. Annual rehabilitation costs average $17,000 annually.9 Surgical costs associate with
amputation can range from $20,000-60,000 ($40,000 avg)10 while the average cost for a post amputation myoelectric prosthetic arm is
$60,000.11 Static orthoses average $1,200 while a myoelectric EWHO average cost is in line with that of a myoelectric prosthetic.
Figure 2 summarizes average cost associated with BPI over a 5 year period with various treatment strategies. Several treatments are
often utilized simultaneously (rehabilitation and therapy is common over a five year period to both a prosthetic and static orthosis while a
myoelectric EWHO user does not require long term therapy).
Post Surgical Treatment for BPI
$250,000
$200,000
$150,000
$100,000
W
tri
lec
yo
e
M
ab
ilit
ati
o
cE
nO
nly
St
Re atic
ha Or
bil tho
ita si
tio s w
n
ith
$0
HO
$50,000
Re
h
Five-Year Treatment
Cost (USD)
Am
Pro pu
sth tati
eti on
c, R wi
eh th
ab
Figure 2.
Treatment costs should be considered in the context of the long term benefit they can provide (Table 1). A cost benefit examination shown
in Figure 3 indicates that a myoelectric EWHO can offer a lower cost, post surgical treatment solution with greater clinical value than other
prescription treatments.
Clinical Value vs. Cost
CLINICAL VALUE SCORE
25
Myoelectric EWHO
20
15
Amputation with
Prosthetic, Rehab
Rehab Only
10
Static Orthosis with Rehab
5
0
,00
50
$2
$2
00
,00
0
0
$1
50
,00
0
,00
00
$1
$5
0,0
00
0
FIVE YEAR COST
Conclusion
Traumatic brachial plexus injury resulting from motor vehicle accidents results in approximately 10,000 cases of hemiparesis annually
despite surgical intervention. Post surgical options include amputation with prosthesis, continued rehabilitation, fitting of a static
orthosis to control a flailing arm and provision of a myoelectric EWHO to provide functional capability and continuous ranging of
the upper limb. A comparison across all treatments which assesses clinical and economic value was performed. This comparison
indicated that a myoelectric EWHO can offer significant clinical value as it can help the BPI patient perform functional tasks and other
ADLs that the other treatments could only partially provide or not provide at all. From an economic standpoint, the myoelectric
EWHO demonstrated an overall lower five year cost than other treatments. The cost/benefit associated with the myoelectric EWHO
was substantially lower than that associated with other post surgical treatments for BPI.
A myoelectric EWHO can be an
effective treatment pathway as the
device will support the weakened
arm and range the elbow, wrist
and hand through user intention.
Clinically, this enables the
performance of goal driven ADLs
in therapy clinic and home and
may help to avoid overuse of the
unaffected arm.
Myoelectric Elbow-Wrist-Hand Orthosis
References
1.
2.
https://en.wikipedia.org/wiki/Brachial_plexus_injury.
Vasileios I. Sakellariou, et al., Brachial Plexus Injuries in Adults: Evaluation and Diagnostic Approach, ISRN Orthopedics, Volume 2014,
Article ID 726103, p. 3.
3. John W. Michael, James A. Nunley, Special Considerations: Brachial Plexus Injuries: Surgical Advances and Orthotic/Prosthetic Management, Atlas of Limb Prosthetics: Surgical, Prosthetic and Rehabilitation Principles, Chapt. 12A.
4. U.S. National Highway Traffic Safety Administration, Traffic Safety Facts, 2009 annual.
5. U.S. Dept. of Transportation, National Highway Traffic Safety Administration, Traffic Safety Facts, DOT HS 812101, Dec 2014.
6. Department of Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada, Epidemiology of brachial plexus
injuries in a multitrauma population, Neurosurgery. 1997 Jun;40(6):1182-8.
7. Marcelo Rosa de Rezende, Gustavo Bersani Silva et al., What has changed in brachial plexus surgery?, CLINICS 2013;68(3):411-418.
8. Kretschmer, et al., Patient Satisfaction and Disability After Brachial Plexus Surgery, Neurosurgery, Oct 2009, pp. 189-196.
9. Reported Patient Experience, United Brachial Plexus Network. www.ubpn.org
10. Godwin KM, Wasserman J, Ostwald SK., Cost associated with stroke: outpatient rehabilitative services and medication, Top Stroke
Rehabil. 2011 Oct;18 Suppl 1:676-84. Cost Helper Health, Amputation Cost, http://health.costhelper.com/amputation.html.
11. Cost Helper Health, Prosthetic Arm Cost, http://health.costhelper.com/prosthetic-arms.html
Myomo, Inc.
One Broadway, 14th FL
Cambridge, MA 02142
(877) 736-9666
[email protected]
www.myomo.com
PN 25549, Rev 2