Medicare Coverage Policy ~ Decisions
Ultrasound Stimulation for Nonunion Fracture Healing
(#CAG-00022)
Decision Memorandum
TO: |
File: CAG-00022 Ultrasound Stimulation for Nonunion
Fracture Healing |
FROM: |
Sean Tunis, MD, MSc Director, Coverage and Analysis
Group
John Whyte, MD, MPH Medical Officer, Coverage and
Analysis Group
Peter Peraud Policy Analyst, Coverage and Analysis
Group |
RE: |
National Coverage Decision |
DATE: |
July 31, 2000 |
This memo serves four purposes: (1) outlines the physiology of
normal fracture healing; (2) reviews the history of Medicare’s
coverage policy on ultrasound stimulation for fracture healing; (3)
analyzes the relevant scientific data related to the use of
ultrasound osteogenic bone stimulators for the treatment of
nonunion; (4) delineates the reasons for making a positive national
coverage decision.
Normal fracture healing
Fractures are common injuries with over 6.8 million occurring
yearly in the United States. Over 900,000 fractures each year result
in hospitalization with over half of these hospitalized patients
over 65 years old. Women over 65 years are three times as likely to
suffer a fracture than their male counterparts, with the majority of
these injuries affecting the hip or distal forearm.
The body is normally able to effectively heal fractures with
conservative medical treatment. Like most biological processes,
normal fracture healing is complex and involves the integrated
action of numerous cells, genes, and minerals. The process can be
simplified into three main stages – inflammatory, reparative,
and remodeling.
Inflammatory: The physical
disruption of the bone, blood vessels, and surrounding soft tissue
causes the formation of a hematoma (collection of blood in the
fracture site) and edema. Following tissue necrosis in the area,
macrophages and osteoclasts are recruited to remove the biological
debris. The stimulation and proliferation of osteoblasts (which
build bone) and endothelial cells (which line blood vessels) mark
the end of the inflammatory phase.
Reparative: A soft callus of fibroblasts
(containing collagen), osteoblasts, and chondroblasts (which build
cartilage) begins to form within two weeks after injury. Type II
collagen is the main component of the cartilage matrix that
initially begins to bridge the fracture gap. Via a process called
endochondral ossification, the soft callus transforms into a hard
callus of woven bone. Woven bone (immature bone with random collagen
and bone cell orientation) can develop into a bony union within 2-3
months postfracture.
Remodeling: Through the action of osteoclasts and
osteoblasts, the initial woven bone is structurally modified to
lamellar bone. Lamellar bone consists of highly organized mineral
plates designed to withstand maximum stress. This final phase could
take years, resulting in a bone that may be thicker and stronger
than the original.
In addition to the local cell recruitment and gene expression,
many other factors are involved in the healing of a fracture. The
severity of the fracture, the nature of the blood supply, the extent
of soft tissue damage, the involvement of a tumor, or infection can
alter the successful union of a fracture. Health considerations such
as diabetes, vascular insufficiency, osteoporosis, anemia, hormone
deficiency, smoking, age, or certain medications can also affect the
quality and rate of fracture healing. Because of the comorbidities
associated with aging, health considerations are especially
important for the Medicare population who sustain fractures.
Definition of nonunion
Even with standard orthopedic management, 5-10% of fractures do
not heal as well or as quickly as expected. These healing disorders
are designated as delayed union or nonunion.
- Delayed union
is normally defined when healing has
not advanced at the "average" rate for the location and type of
fracture.
- Nonunion
is defined as the point when healing has
stopped and will not proceed without some type of intervention.
The Medicare program has recently set criteria for the definition
of nonunion.
Nonunion of a long bone fracture must be documented by a minimum
of two sets of radiographs obtained prior to starting treatment with
the osteogenesis stimulator, separated by a minimum of 90 days, each
including multiple views of the fracture site, and with a written
interpretation by a physician stating that there has been no
clinically significant evidence of fracture healing between the two
sets of radiographs.1
Current treatment of nonunion
Treatment options for nonunion range from various surgical
techniques to noninvasive electrical, electromagnetic, or ultrasound
stimulation. Surgical techniques may include Ilizarov external
fixation, intermedullary nails, compression plates, screws, pins, or
bone grafts. Reported success rates for surgical treatment of
nonunion have ranged from 68-96%. Overall, successful treatment of a
nonunion often depends on reduction of the fracture, bone grafting
if necessary, and stabilization (internal or external fixation).
Electrical, electromagnetic, or ultrasound stimulation may be
options for cases in which surgery is not an option. These methods
may require the implantation of electrodes or external application
of the device. It has been shown that mechanical or electrical
stimuli can send regulatory signals to the bone causing physical
remodeling of the tissue.
Ultrasound treatment is used in conjunction with stabilization of
the fracture, and the therapy is used both as an alternative to
surgery or as a second therapeutic option after surgical failure.
Specific biological effects have been attributed to ultrasound
stimulation including increased signaling pathways in osteoblasts,
increased release of growth factors, increased blood flow to the
fracture site, and an increased expression of the aggrecan gene.
Aggrecan is a proteoglycan that incorporates with the Type II
collagen during the reparative phase of fracture healing.
History of Medicare’s Coverage Policy on Ultrasound for Fracture
Healing
Ultrasound osteogenic stimulators fall under the benefit category
of durable medical equipment (DME). Currently, the Medicare program
does not cover ultrasound therapy for fracture healing. Coverage
Issues Manual section 35-48 states:
- Ultrasonic Osteogenic Stimulators.--An
ultrasonic osteogenic stimulator is a non-invasive device that
emits low intensity, pulsed ultrasound. The ultrasound signal is
applied to the skin surface at the fracture location via
ultrasound, conductive, coupling gel in order to accelerate the
healing time of the fracture. The device is intended for use with
cast immobilization.
There is insufficient evidence to support the medical necessity
of using an ultrasonic osteogenic stimulator. Therefore, the
device is not covered, because it is not considered reasonable and
necessary.
The ultrasound device consists of two main components – a signal
generator and a small, square transducer connected to the generator.
Though the definite biological effects of the ultrasound are not
clear, the device does not substantially increase the temperature of
the tissue and operates at an intensity of 30 mW/cm2,
nearly one hundred times less than some diagnostic ultrasound. Its
effects are generally attributed to the physical signal delivered to
the bone by the acoustic waves, though other biological mechanisms
have been proposed. Some evidence, though limited, is available to
support the effects of ultrasound on all three phases of fracture
healing. Patients typically apply the device to the fracture site 20
minutes/day until the fracture is healed or the prescribing
physician stops the treatment.
Currently, Exogen, Inc.2 is the
only manufacturer of an ultrasound osteogenic bone stimulator. They
initially received Food and Drug Administration (FDA) approval (Pre-
market approval) in October 1994 for the use of the ultrasound
stimulator for the treatment of fresh fractures (less than 7 days).
In August 1996, the Technology Advisory Committee (TAC), of the
Health Care Financing Administration (HCFA), reviewed available data
relating to ultrasound treatment and found insufficient evidence for
effectiveness in the Medicare population. The TAC was also concerned
that the available studies excluded patients who were receiving
anticoagulants, prescription non-steroidal anti-inflammatory
medications (NSAIDs) or calcium channel blockers, those with a
history of thrombophlebitis, vascular insufficiency, alcoholism or
nutritional deficiency. At that point, HCFA revised the Coverage
Issues Manual section 35-48 to issue a noncoverage policy of
ultrasound for all indications.
In November 1998, ultrasound for the treatment of fresh fractures
was revisited. The national noncoverage decision was officially
reviewed and re-issued. HCFA determined that there was a lack of
functional benefits attributable to ultrasound therapy, a failure to
determine effectiveness in the elderly population, and a failure to
demonstrate the prevention of delayed union or nonunion.
Of note, this decision memorandum only addresses the topic of
ultrasound stimulation for the treatment of established nonunions.
The noncoverage policy for fresh fractures is not addressed in this
document.
Recent Developments and Timeline of Activities
February 2000 |
FDA approved Exogen’s ultrasound device for
the non-invasive treatment of established nonunions excluding
the skull and vertebra. |
April 20, 2000 |
Representatives from Exogen met with members of the
Coverage and Analysis Group at HCFA central office to
informally discuss the new coverage process and their options
for pursuing coverage. |
May 2, 2000 |
A letter from Exogen was sent to HCFA requesting a formal
review of the non-coverage policy for the treatment of
established nonunions. |
May 8, 2000 |
HCFA officially accepted Exogen’s request for a national
coverage decision. |
May 12, 2000 |
HCFA informed Exogen that a response to the formal request
would be generated in 90 days. This memorandum serves as the
response to the national coverage request for the nonunion
indication. |
June-July 2000 |
HCFA supplemented the information provided by Exogen by
independently conducting an extensive literature review.
Members of the Coverage & Analysis Group spoke with
several authors of articles to clarify information and engaged
in significant dialogue with
Exogen. |
Analysis of Scientific Data
For a detailed review of the materials examined, refer to Appendix
A. The materials include peer-reviewed articles, unpublished
articles, and conference proceedings.
Exogen provided HCFA with three published articles, one published
review and a summary of the safety and effectiveness data presented
to the FDA (which included 2 unpublished articles) for the
ultrasound treatment of nonunions. Additionally, a Medline search
with the terms "ultrasound," "fracture," "fracture
healing," "nonunion," and "osteogenesis" was performed
and returned an additional case report on the use of ultrasound for
nonunion. HCFA also obtained one unpublished review, and, in
addition, six unpublished articles that were analyzed for this
decision.
Issues Related to Coverage of Ultrasound Stimulation for
Nonunion
In addressing the national noncoverage policy regarding the use
of ultrasound osteogenic stimulators for the treatment of nonunion
fractures, the following questions arise:
- Is the evidence adequate to determine the effectiveness of
ultrasound osteogenic stimulation for the treatment of
nonunions?
- Is the evidence applicable to the Medicare population?
- What are the relevant functional and clinical outcome
measures?
- Is ultrasound stimulation effective for nonunions in all types
of bones?
In order to address the adequacy of the
evidence, several issues need to be discussed. The first
issue is study design. It is important to recognize that
there is a hierarchy of evidence based on the methodology employed
in a study. The most rigorous, well-designed studies are
prospective, randomized clinical trials; however, such studies are
not possible fin every clinical situation. The studies for the
ultrasound treatment of nonunions are all case series, with some
statistical analysis using self-paired controls within those
populations. Investigators have asserted that receiving approval
from an Institutional Review Board (IRB) for a nonunion study
involving placebo devices would be difficult. HCFA acknowledges the
concerns associated with providing placebo to nonunion fractures
that, by their own definition, have no sign of healing without some
active intervention. Therefore, although preferable, it might be
impractical to require manufacturers to conduct placebo-controlled
studies on this patient population.
There are, however, better, alternative study designs which
should have been considered. For example, the ultrasound stimulator
could be compared to the other noninvasive treatments or to surgical
intervention. Such a comparative analysis would be of interest to
HCFA.
One of the potential problems with the study designs used for the
evaluation of ultrasound treatment for nonunions stems from the fact
that all the studies are retrospective. Patients were entered into
the studies based on certain inclusion/exclusion criteria, but those
criteria were not developed a priori; rather, they were
initiated after the patients had already been treated. The fact that
the patients for the study were selected only from patients that had
been treated by the device precludes these studies from being
considered historically prospective. By designing a study after the
patients and their outcomes are documented, the study design could
introduce a systematic bias. Which types of patients were initially
prescribed the device? Were these patients representative of the
patient population that would ultimately use the device? Was there
anything distinct about the fractures treated with the device?
An added concern is that all reports involving US patients are
based on Exogen registry data accumulated since October 1994.3, 4
Registry data has the potential for bias because the registry could
contain only selected patients that meet certain criteria. Because
of such bias, it is often difficult for registries to demonstrate
causality. The sufficiency and adequacy of registry data needs to be
determined on an individual basis. In this series of studies, bias
is reduced since all patients treated with the device in the United
States since October 1994 have been documented in the registry
regardless of fracture type, compliance, or outcome.5 For
the decision relating to fresh fractures, the registry was not
sufficient evidence on which to base a coverage decision. The
registry data did not provide comprehensive information about
functional and clinical outcomes in the fresh fracture population
(cast removal, return to work time, time to weightbearing), nor did
it provide appropriate statistical analyses of variables; therefore,
it did not represent adequate evidence for that population. For the
nonunion population, however, the outcome of healed/failure to heal
is a clinically relevant outcome that is provided by the
registry.
A further problem with the registry data is the overlap between
studies. The studies that analyze the registry data often look at
populations including the same patients. For instance, the
Heppenstall study contains patients entered in the registry between
October 17, 1994 and October 17, 1996, and a Mayr article studies
patients entered in the registry between October 17, 1994 and July
14, 1997. The strength of the overall body of evidence is weakened
by the fact that the individual studies use many of the same
patients.
In an effort to validate the results from the registry, Mayr. et
al., in two separate studies of the registry population conducted at
different times, compared data from a separate German population to
the United States data.6 The
German population was composed of consecutive patients treated with
the ultrasound device in clinics around Germany and was part of a
study later published by Gebauer et al. The German study followed
additional inclusion criteria to limit confounding factors that may
contribute to healing. The cases were all reviewed by the
investigators to ensure that healing had stopped and that the last
surgical intervention was at least two months before ultrasound
treatment. Comparisons were then conducted based on nonunion heal
rate, average healing time, average fracture age, and median
fracture age. A student’s t-test comparing average healing time and
average fracture age between groups showed no significant
difference; the nonunion healed rates were similar (83% US v. 93%
German and 86% US v. 94% German), but statistical analysis was not
provided.
Another concern related to study design relates to the
statistical analysis. The studies reviewed for this decision either
simply report a percent of patients healed or present a statistical
comparison using the patient as his/her own control. For the
statistical comparisons, the authors assume a healed rate of £ 5% as the null hypothesis.7 For
the studies that computed a statistical comparison, the p-values
were significant (p£ 0.00001) both for
overall results and intention-to-treat groups. The self-paired
analysis is appropriate in this case and limits potential
significant differences between treatment and control groups.
Given the concerns about placebo devices and the limited
alternatives for studying this population, the use of registry data,
as well as self-paired, retrospective study design is minimally
acceptable for determining the effectiveness of the ultrasound
device for the treatment of nonunion.
The second issue when assessing the adequacy of evidence is the
consistency of the results. If the studies available on a
certain technology are inconsistent, the actual effectiveness of the
device is difficult to determine. The articles reviewed for this
decision are fairly consistent both in terms of design and outcome.
All the studies use an outcome of healed versus failure to heal;
they all require a fracture age of at least six months; and they all
utilize ultrasound treatment without concomitant treatment. As
mentioned earlier, some of the studies use more rigorous inclusion
criteria. The German study and Frankel’s analysis of the tibia
nonunions required a four-month interval between the last surgery
and the start of treatment while Heppenstall required three months.
The German, French, and Dutch studies as well as the Frankel and
Heppenstall studies required radiographic assessment of the fracture
to ensure nonunion.
An unpublished retrospective analysis of the registry data by
Heppenstall et al. separated the US data into two groups based on
expanded inclusion criteria (9 month fracture age, 3 months since
surgical intervention). The patients that met the 3 month
post-surgery requirement, in addition to a 9 month fracture age,
were designated as the core group and showed an 80% healed rate.
Using the patients as his/her own control, a comparison of core
group heal rates was statistically significant (p=0.00001).
The most recent report of the registry data is in unpublished
data provided by Exogen that looks only at patients that have
completed treatment with the ultrasound device. This review of all
the registry data reports a nonunion (256 days post-fracture) heal
rate of 83%.
Overall, the studies and reviews found heal rates for nonunions
between 80-100% (See Table 1). The intention-to-treat values ranged
from 64-82%.8
Table 1: Nonunion Results
Author |
Overall Heal Rate |
Heal Rate (Intention to Treat) |
p-value |
Gebauer D, Mayr E, Orthner E, Heppenstall RB, McCabe
JMy |
85% (57/67) |
82% (70/85) |
p<0.00001 |
Nolte PA, van der Krans A, Patka P et al.y |
86% (25/29) |
80% (33/41) |
p<0.00001 |
Mayr E, Frankel V, Ruter A |
86% (314/366) 94% (15/16)Æ
|
Not Performed |
Not performed |
Moyen B, Mainard D, Azoulai J et al.* |
89% (39/44) |
75% (39/52) |
p=0.00001 |
Heppenstall RB, Frey JJ, Ryaby JP, McCabe J* |
80% (249/313) |
64% (351/551) |
p=0.00001 |
Frankel VH, Koval KJ, Kummer FJy
|
84% (146/174) |
Not Performed |
Not Performed |
Mayr E, Wagner S, Ruter A |
83% (201/241) 93%Æ |
Not Performed |
Not Performed |
Choffie M, Duarte L* |
100% (26/26) |
Not Performed |
Not Performed |
Exogen Registry Data (June 15, 2000) |
83% (1283/1546) |
Not Performed |
Not
Performed |
*Unpublished articles y Submitted for
publication Æ German patients used for
comparison analysis
Another consideration with respect to study design centers on the
applicability of the study procedures beyond the research
setting. The majority of the patients studied in these studies were
treated at home under the instruction of their own physician.
Therefore, the studies conducted on the ultrasound treatment of
nonunion are relevant to the everyday clinical setting.
Given that the results are applicable in the clinical setting,
one must then ask whether those same results applicable to
the Medicare population. The healing process is slower in
the older population, but age has not been proven an independent
predictor of healing disorders. Rather, comorbidity is the issue, of
which age is most likely a covariate. Other factors, such as
diabetes, vascular insufficiency, or certain prescription
medications are correlated with advanced age and can affect the rate
of healing. Of note, four of the studies analyzed for this decision
stratified heal rates by age and found no significant difference
among age groups.
The third main issue in analyzing the data is the
clinical/functional relevance of the outcome
measures. The studies reviewed all use a primary outcome
measure of healed or failure to heal. Healed is generally defined by
radiographic guidelines (3 of 4 cortices bridged for long bones or
soft callus bridge of the fracture gap) and clinical assessment (no
pain with gentle stress or weightbearing). The dichotomous outcome
(healed/failure to heal) is the accepted measure of success of the
treatment. As previously discussed, nonunions are, by definition,
unable to heal without some type of intervention. In that case, an
outcome of healed, in the absence of any concurrent therapy, can be
attributed to the ultrasound therapy and would be clinically
relevant.
Many of the studies also use heal time, measured in days, as a
second outcome measure. Heal time, without associated functional
outcomes, has limited clinical relevance. Even if a study indicated
that ultrasound therapy worked more quickly than alternative
treatments, the functional benefits of earlier healing would have to
be addressed. For example, do patients return to work sooner? Is
time to weightbearing reduced? Are casts removed more rapidly? Is
there a reduction in morbidity?
The fourth issue to consider when analyzing the data is the
effectiveness of ultrasound treatment for different types of
bones. Because bones have diverse function, blood supply,
and structure, the effects of the ultrasound stimulator may vary for
different bones.
Of the articles reviewed, three studies (Gebauer, Moyen,
Heppenstall) statistically compared heal rates for long bones vs.
other bones. Two of the three studies shows no difference in heal
rates between long bones and other bones. Gebauer et al. reported a
success rate of 90% for long bones versus 69% for other bones which
was statistically significant (p=0.05). The authors attribute this
difference to the fact that, of the non-long bones that failed, 60%
were atrophic scaphoids over 10 years old. Four studies (Gebauer,
Moyen, Heppenstall, Nolte) statistically compared heal rates across
all individual bones that could have included short, long, flat and
irregular bones. Three of the four studies showed no statistical
difference. Again, the Gebauer analysis resulted in a statistically
significant difference showing a heal rate of 33% in the scaphoid
versus 100% in the clavicle (p=0.02). This difference most likely
resulted from the atypical age and structure of the scaphoid
nonunions. In the other studies reviewed in this analysis, scaphoid
heal rates typically varied from 80-100% (See Table 2).
An analysis of the registry data (See Table 3) reveals that other
non-long bones have similar heal rates to long bones. Heal rates
range from 72-94%, which are consistent with the results for long
bones.
Table 2: Heal Rates by Bone Type
Bone Type |
Heal Rates |
US registry as of 6/15/00 |
Brazil |
France |
Germany |
Netherlands |
Humerus |
102/148 (69%) |
1/1 (100%) |
1/1 (100%) |
2/3 (67%) |
1/1 (100%) |
Femur |
213/259 (82%) |
7/7 (100%) |
5/5 (100%) |
11/12 (92%) |
4/5 (100%) |
Radius /Ulna |
108/127 (85%) |
1/1 (100%) |
6/6 (100%) |
5/6 (83%) |
4/5 (80%) |
Scaphoid |
101/118 (86%) |
5/5 (100%) |
Not Reported |
2/6 (33%) |
4/5 (80%) |
Tibia /Fibula |
421/503 (84%) |
12/12 (100%) |
21/25 (84%) |
23/25 (92%) |
10/10 (100%) |
Metatarsal |
81/91 (89%) |
Not Reported |
Not Reported |
5/5 (100%) |
1/1 (100%) |
Ankle |
69/75 (92%) |
Not Reported |
1/1 (100%) |
1/2 (50%) |
0/1 (0%) |
Clavicle |
40/48 (83%) |
Not Reported |
1/1 (100%) |
3/3 (100%) |
1/1 (100%) |
Others* |
148/177 (84%) |
Not Reported |
4/5 (80%) |
5/5 (100%) |
Not
Reported | *Other
bones include hamate, hip, knee, lunate, patella, rib, scapula,
shoulder, sternum, trapezoid, triquetrum, foot, pelvis, phalanx,
wrist, tarsal navicular, calcaneus, metacarpal, and vertebra.
Table 3: "Other" Bones from Registry
Bone |
Heal Rate |
Calcaneus |
16/17 (94%) |
Pelvis |
10/12 (83%) |
Phalanx |
11/13 (85%) |
Foot |
46/56 (82%) |
Wrist |
13/18 (72%) |
Tarsal Navicular |
14/15 (93%) |
Others |
38/46 (83%) |
Conclusion
In conclusion, HCFA’s analysis of the data suggests that
ultrasound osteogenic bone stimulation is a reasonable and necessary
treatment for established nonunions. Although the evidence and the
study designs were minimally acceptable, the study results were
consistent and applicable to the Medicare population. Additionally,
the outcome measures were clinically and functionally relevant, and
these outcomes were similar for all types of bones.
The policy will cover nonunions for fractures of all bone types;
however, the policy will limit the use of the ultrasound stimulator
to patients that have failed one prior surgery for the fracture. The
prior surgery requirement is based on the characteristics of the
patient population studied in the international studies (Gebauer,
Moyen, Nolte) in which nearly 80% of the patients had at least one
prior surgical intervention. This decision, as well as the FDA
approval, relies primarily on these foreign studies, which were more
well-controlled and rigorous than the Exogen registry. Coverage for
patients who cannot undergo surgery due to comorbidities, or who
refuse surgery will be considered as more information becomes
available.
We encourage physicians, patients, and manufacturers to engage in
further dialogue with HCFA concerning the study designs necessary to
expand this coverage. If 80% of nonunions can be healed with the use
of the ultrasound device, a prospective comparison to surgical
intervention as a primary nonunion treatment would strengthen the
evidence, and potentially demonstrate an important improvement in
clinical care for patients with nonunions.
As Medicare continues to implement a more evidence-based decision
making process, the question of study design becomes increasingly
important. The use of the registry as part of this coverage
determination was based on the specific nature of nonunion and the
relevant outcomes provided by the registry. This particular decision
should not be viewed as an assertion that registries are generally
acceptable forms of evidence on which to base coverage decisions. As
stated in the document, there is no requirement that all
technologies be supported by randomized, prospective,
placebo-controlled studies; however, technologies should be
supported by studies that utilize the best design possible, giving
the most clinically useful and functional outcomes. Regardless of
the fact that the registry was allowed as a substantive portion of
the data in this case, better, prospective clinical trials could
have been performed. The evaluation of technologies based on the
most well-designed studies for a particular technology or disease
will benefit both the device industry and Medicare
beneficiaries.
Rescind the national noncoverage policy for Ultrasonic Osteogenic
Stimulators.
Amend CIM 35-48 to state:
B. Ultrasonic Osteogenic Stimulators.--An
ultrasonic osteogenic stimulator is a non-invasive device that emits
low intensity, pulsed ultrasound. The ultrasound signal is applied
to the skin surface at the fracture location via ultrasound,
conductive, coupling gel in order to stimulate fracture
healing.
Ultrasonic osteogenic stimulators are covered as medically
reasonable and necessary for the treatment of fractures only when
the following conditions are met:
- Nonunion of a fracture must be documented by a minimum of two
sets of radiographs obtained prior to starting treatment with the
osteogenesis stimulator, separated by a minimum of 90 days, each
including multiple views of the fracture site, and with a written
interpretation by a physician stating that there has been no
clinically significant evidence of fracture healing between the
two sets of radiographs.
- Patient must have documented failure of at least one surgical
intervention for the treatment of the fracture.
Nonunions of the skull, vertebrae, and those that are
tumor-related are excluded from coverage.
The ultrasonic osteogenic stimulator may not be used concurrently
with other noninvasive osteogenic devices.
The national noncoverage policy relating to ultrasonic osteogenic
stimulators for fresh fractures and delayed unions remains in place.
This policy relates only to nonunion as defined above.
1 See Decision Memorandum Electrical
Stimulation for Fracture Healing, November 9, 1999, at
http://www.hcfa.gov/quality/8b.htm 2
Exogen was recently acquired by Smith & Nephew of Memphis,
Tennessee. 3 Physicians that prescribed
the ultrasound device completed periodic documentation of their
patient's demographics, case specifics, and outcome. The most recent
published studies analyze patients through July 14, 1997. At that
time, there were 6,535 fractures that had completed treatment. As of
June 15, 2000, 10,056 fractures in the United States had completed
treatment with ultrasound. 4 The other
studies (Gebauer et al., Nolte et al., Moyen et al., and Choffie)
involve German, Dutch, French, and Brazilian patients that are not
included in Exogen's registry. 5
Questions remain, however, about the accuracy and completeness of
the Exogen registry. 6 Of note, the FDA
relied primarily on the Gebauer (German) and Nolte (Netherlands)
studies for the PMA approval. 7 Authors
conservatively chose 5% heal rate though they note that nonunions
have essentially a zero probability of healing without intervention.
Such an assumption underestimates any positive effect. 8 This is a modified intent-to-treat analysis,
since this type of statistical testing is used only for randomized
control trials.
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