U.S. patent application number 09/919063 was filed with the patent office on 2001-12-20 for apparatus and method for stabilizing pelvic ring disruption.
Invention is credited to Bottlang, Michael, Krieg, James C., Long, William B., Madey, Steven M..
Application Number | 20010053884 09/919063 |
Document ID | / |
Family ID | 26879359 |
Filed Date | 2001-12-20 |
United States Patent
Application |
20010053884 |
Kind Code |
A1 |
Krieg, James C. ; et
al. |
December 20, 2001 |
Apparatus and method for stabilizing pelvic ring disruption
Abstract
A pelvic sling device is provided for reducing a fractured
pelvis. The device includes a belt member and a buckle component
that automatically locks at an optimal predetermined tension level
to provide distributed hoop-like compression and reduction for a
fractured pelvis.
Inventors: |
Krieg, James C.; (Portland,
OR) ; Long, William B.; (Portland, OR) ;
Madey, Steven M.; (Lake Oswego, OR) ; Bottlang,
Michael; (Portland, OR) |
Correspondence
Address: |
KOLISCH HARTWELL DICKINSON MCCORMACK & H
EUSER
520 S.W. YAMHILL STREET
SUITE 200
PORTLAND
OR
97204
|
Family ID: |
26879359 |
Appl. No.: |
09/919063 |
Filed: |
July 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09919063 |
Jul 31, 2001 |
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09639544 |
Aug 16, 2000 |
|
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60183623 |
Feb 18, 2000 |
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Current U.S.
Class: |
602/19 |
Current CPC
Class: |
A61F 5/0193
20130101 |
Class at
Publication: |
602/19 |
International
Class: |
A61F 005/00 |
Claims
We claim:
1. A method of stabilizing a fractured pelvis comprising securing a
belt around a person's fractured pelvis, and automatically setting
the belt at a tension level that has been predetermined to
substantially reduce a fractured pelvis without excessive
compression.
2. The method of claim 1, wherein the setting step includes the
step of operating a buckle device that automatically establishes an
appropriate circumference for the belt when the tension on the belt
is in the range of approximately 150 N to 250 N.
3. The method of claim 2 further comprising the step of conducting
x-ray analysis through the belt to acquire information about the
fracture.
4. The method of claim 2, wherein the securing step includes the
step of securing the belt symmetrically by pulling on opposite end
portions of the belt simultaneously, thereby stabilizing the
fractured pelvis evenly.
5. A method of securing a pelvic fixator comprising temporarily
reducing a fractured pelvis by tightening a belt device around a
person's pelvis, and securing a pelvic fixator while the belt is
secured around the person's pelvis.
6. The method of claim 5 further comprising the step of
automatically setting an appropriate tension on the belt by
providing a buckle that locks and maintains a circumference for the
belt when the tension is in the range of approximately 150 N to 250
N.
7. A method of reducing a pelvic fracture comprising applying
circumferential external distributed pressure around a person's
pelvis by securing a belt having a tension in the range of
approximately 150 N to 250 N.
8. The method of claim 7 further comprising the step of
transporting the person to a hospital.
9. A method of stabilizing a fractured pelvis in an emergency
situation comprising securing a sling member around a person's
fractured pelvis, and tightening a sling member by operating a
buckle mechanism that exhibits a hysteresis effect between the
minimal force required to lock the buckle and the maximal force
required to unlock the buckle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional patent application from
U.S. patent application Ser. No. 09/639,544 filed Aug. 16, 2000
titled "Apparatus and Method for Stabilizing Pelvic Ring
Disruption" which application claims priority from U.S. Provisional
Patent Application Serial No. 60/183,623, filed Feb. 18, 2000, and
are both hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates to emergency treatment of a fractured
pelvis. In particular, the invention provides a non-invasive sling
device for reducing a fractured pelvis in a manner that minimizes
internal bleeding.
BACKGROUND OF THE INVENTION
[0003] Many people die from internal bleeding due to a fractured
pelvis. Achieving rapid hemodynamic stability in patients who have
a fractured pelvis decreases the mortality rate substantially.
Unfortunately, currently there is no satisfactory method or device
that may readily be utilized to stabilize a fractured pelvis in
emergency situations outside a hospital. Pelvic stabilization at an
emergency site within the first hour after the fracture occurs is
critical and may often determine whether the patient lives or
dies.
[0004] Reduction and stabilization of the pelvis is thought to be
the most effective means to control bleeding for the following
reasons. First, it decreases fracture fragment motion to prevent
dislodgment of hemostatic clots and further tissue damage. Second,
fracture reduction reopposes bleeding osseous surfaces, thus
decreasing blood loss. Third, reduction decreases pelvic volume,
thereby tamponading hemorrhage from the fracture and
retroperitoneal tissue. Despite these widely recognized benefits,
no adequate pelvic stabilization device for early management of
pelvic fractures is currently available.
[0005] The current standard of care for treating pelvic trauma
consists of fluid resuscitation, including appropriate use of blood
products, angiography if necessary, and early invasive or
non-invasive pelvic stabilization. Non-invasive pelvic
stabilization techniques have been used. For example, a sheet may
be wrapped around the pelvis and tied. Alternatively, a vacuum-type
splinting device, or a pneumatic anti-shock garment may be used.
These non-invasive techniques have a number of significant
problems. One problem is that successful use and application of the
device is quite dependent on the emergency caregiver. The person
applying the device may not know how much compressive force to
apply circumferentially around the pelvis. If too much force is
applied, then the pelvis may be overly compressed causing
significant complications. On the other hand, insufficient
compressive force may leave the fractured pelvis unreduced, and
therefore fail to adequately control internal bleeding.
[0006] Another problem with non-invasive pelvic stabilization
devices that are currently used is that they typically prohibit or
restrict vital access to the abdomen, perineum, and lower
extremity. Furthermore, prolonged application of devices such as
the pneumatic anti-shock garment has been associated with
significant complications, such as compartment syndrome of the
lower limbs.
[0007] Invasive pelvic stabilization methods utilize external
fixation, pelvic C-clamps, and open reduction and subsequent
internal fixation. External fixation devices can effectively reduce
and stabilize the pelvis and are relatively simple to apply.
However, their utility is limited most commonly to the operating
room setting. The invasive pelvic stabilization methods generally
are not appropriate for application at an emergency scene where
unstable pelvic ring disruptions require rapid pelvic reduction and
temporary stabilization.
[0008] Open reduction and internal fixation is the ultimate form of
treatment for a fractured pelvis, and is considered the gold
standard for accuracy of reduction, protection of neurovascular
structures, and rigidity of fixation. However, its invasive nature
makes it inappropriate for use in an emergency situation, such as
the scene of a car accident, on the side of a mountain, or at a
remote location of a traumatic fall.
[0009] Accordingly, an object of the invention is to provide a
method and apparatus for pelvic reduction and stabilization that is
non-invasive.
[0010] Another object is to provide a method and apparatus for
pelvic reduction and stabilization that is capable of even and
incremental application of hoop stress to both hemi-pelves while
avoiding reactive forces that potentially can decrease the quality
of reduction.
[0011] Another object of the invention is to provide a method and
apparatus for pelvic reduction and stabilization that applies and
maintains hoop stress around the pelvis at a preset and safe level,
while avoiding the application of excessive hoop stress.
[0012] A further object of the invention is to provide a method and
apparatus for stabilization of a fractured pelvis that can be
applied in a rapid and simple manner by a single person without
extensive training.
[0013] Still another object of the invention is to provide a method
and apparatus for stabilizing a fractured pelvis that can be
applied at an emergency site without the need for additional
complex or heavy equipment.
[0014] Another object of the invention is to provide a method and
apparatus for stabilizing a fractured hip in a nonintrusive manner,
while allowing vital access to conduct other important emergency
procedures on the patient.
[0015] Another object of the invention is to provide a method and
apparatus that permits stable pelvic reduction prior to and during
the application of a pelvic external fixator in the clinical
setting.
SUMMARY OF THE INVENTION
[0016] The invention provides beneficial methods and apparatus for
stabilizing a fractured pelvis in an emergency setting without
requiring use of complex or invasive equipment. The invention may
be used and carried out by a single person without extensive
training or expertise.
[0017] The invention provides a sling device for stabilizing a
fractured pelvis. A buckle is connected to a strap member to form a
closed loop. The buckle has at least one automatic locking
mechanism that allows the strap member to be tightened around a
fractured pelvis until a predetermined threshold force is reached.
The closed loop then maintains a substantially constant
circumference until the strap member is released from the
buckle.
[0018] The invention also provides a sling device including a belt
member with two end portions. A buckle has two substantially
identical belt-engaging mechanisms. Each belt engaging mechanism is
configured to receive an end portion of the belt member so that the
belt member can be tightened symmetrically around a person's pelvis
by pulling on the end portions of the belt member
simultaneously.
[0019] In a preferred embodiment of the invention, the belt member
is secured with a buckle including at least one rotating cylinder.
The rotating cylinder has an outer surface that contacts a portion
of the belt member that at least partially wraps around the
cylinder. The belt portion frictionally grips the outer surface of
the cylinder so that when rotation of the cylinder is locked, the
belt member is prevented from slipping over the outer surface of
the immobilized cylinder.
[0020] The invention also provides a method of stabilizing a
fractured pelvis. First, a belt is secured around a person's
fractured pelvis. The tension of the belt is then automatically set
at a level that has been predetermined to substantially reduce a
fracture pelvis without excessive compression. In a preferred
embodiment of the invention, the tension level of the belt is
automatically set in the range of approximately 150 N to 250 N.
[0021] The invention also includes a method of securing a pelvic
fixator in an emergency situation. The fractured pelvis is first
temporarily stabilized by tightening a belt device around the
pelvis. A pelvic fixator may subsequently be applied while the belt
is secured around the person's pelvis.
BRIEF DESCRIPTION OF THE FIGURES
[0022] FIG. 1 is a front view of the pelvic ring.
[0023] FIGS. 2A and 2B are front views of unstable pelvic ring
disruptions.
[0024] FIG. 3 is a top view of a pelvic sling device according to a
preferred embodiment of the invention.
[0025] FIG. 4 is a front view of a pelvic sling applied to a
fractured hip.
[0026] FIG. 5 is a side view of the sling and hipbone structure
shown in FIG. 4.
[0027] FIG. 6 is a perspective view of a buckle for use on a pelvic
sling.
[0028] FIG. 7 is a partial front view of a sling showing one end
portion of the sling engaging the buckle of FIG. 6.
[0029] FIGS. 8-10 are cross-sectional views of the sling shown in
FIG. 7, illustrating a preferred mechanism for locking the tension
of the belt.
[0030] FIG. 11 is a partial cross-sectional view of the buckle
shown in FIG. 6.
[0031] FIG. 12 is a graph illustrating the amount of tension
required to reduce a fractured pelvis when the sling is applied at
different locations.
[0032] FIG. 13 is a bar graph illustrating the results of an
experiment to determine the amount of sling tension required to
adequately reduce the symphysis gap in a fractured pelvis.
[0033] FIG. 14 is a set of four CT images showing a fractured
pelvis before and after sling-induced reduction.
DESCRIPTION OF THE INVENTION
[0034] The invention includes many aspects that may be employed
advantageously to stabilize a fractured pelvis in an emergency
situation. Generally, the invention employs a compressive device
that can be easily applied to a patient to provide an appropriate
level of hoop stress so that the fractured pelvis is reduced but
not overly compressed. Preferred examples and embodiments of the
invention are described below with reference to the figures.
[0035] FIG. 1 shows the bone structure that is referred to as the
pelvic ring 10. The pelvic ring is formed by the sacrum 12, ilium
14, acetabulum 15, ischium 16, pubic rami 17, and symphysis pubis
18. Anteriorly, pelvic ring 10 contains a fibro cartilage joint.
Posteriorly, the pelvic ring 10 contains the sacroiliac joints 20,
which connect the sacrum 12 with the left and right ilium.
[0036] Unstable pelvic ring disruptions are usually manifested by
two or more fracture sites. In an "open book" fracture, as shown in
FIG. 2A, pelvic ring disruption is evident at symphysis pubis 18
and at one or both sacroiliac joints 20. FIG. 2B illustrates a
lateral compression fracture in which pelvic ring disruption occurs
at pubic rami 17 and at sacroiliac joint 20.
[0037] FIG. 3 shows a top view of a sling 30 including a belt
member 32 operatively combined with buckle device 34. Belt member
32 is comprised of two overlapping lateral portions 36a and 36b.
Belt portions 36a and 36b have a variably overlapping region 38 for
making gross adjustments to the circumference of the sling so that
one sling device can be used on people of different sizes. Any
appropriate mechanism may be used to provide variable overlap
fixation of lateral belt portions 36a and 36b, for example, hook
and loop type fasteners, for example, VELCRO.TM., may be utilized
in overlapping region 38.
[0038] FIG. 4 is a front view of a pelvic sling shown in operative
association with a human pelvis. FIG. 5 shows a side view of the
same sling and pelvis of FIG. 4. Pelvic sling 50 has a belt portion
51 including an approximately 6-inch wide posterior sling component
52. Posterior sling component 52 is situated behind sacrum 12 with
its lower edge located at the level of the superior rim 54 of
symphysis pubis 18. Posterior sling component 52 is preferably made
of a radiolucent material that is cushioned toward the skin
interface to ensure a high degree of pressure distribution. The
material is of sufficient stiffness to transmit tensile forces of
at least 200 N without exhibiting strain larger than 10%. The
material also has sufficient inherent elasticity to conform in part
to body geometry. Posterior sling component 52 extends laterally
toward the anterior portion of the abdomen. Symmetrical sling
extensions 56a and 56b gradually decrease in width to approximately
2-inches as they circumvent the sides of the pelvis. The centerline
of sling extensions 56a and 56b is approximately 2-inches above the
lower edge of posterior sling component 52. Sling extensions 56a
and 56b are directed through buckle 58 which is centered over the
abdomen. Buckle 58 reverses the direction of both sling extensions
56a and 56b. Simultaneous application of sideward direct tensile
force to each sling extension 56a and 56b yields in tensioning of
the entire sling, which in turn induces even hoop stress around the
pelvis. The hoop-stress subsequently reduces the geometric
integrity of the disrupted pelvic ring and promotes stability of
the fracture fragments. After application of sling tension at the
appropriate level, the ends of sling extensions 56a and 56b are
attached to lateral sling portions, for example, by hook and loop
fasteners, to maintain sling tension.
[0039] FIG. 6 shows a perspective view of a preferred buckle design
for use on a pelvic sling. Buckle 80 is characterized by
side-to-side symmetry relative to axis AA. Each of lateral buckle
portions 82a and 82b is designed to engage and secure an end of
sling extensions 56a and 56b, respectively, at an appropriate
tension level. The details described below in relation to lateral
buckle portions 82b are the same for lateral buckle portion 82a,
unless expressly distinguished.
[0040] Lateral buckle portion 82b includes rotating cylinder 84
that is free to rotate when buckle 80 is unlocked. As shown in FIG.
7, sling extension 56b wraps around cylinder 84. Cylinder 84
rotates in direction 86 when the sling is being tightened. Holes 88
are provided in cylinder 84, as shown in FIG. 6, for engaging a pin
to lock rotation of cylinder 84 as described in more detail. Gap 90
is defined between cylinder 84 and side bar 92. Gap 90 is
maintained by springs that are not shown in FIG. 11. As belt
tension increases, cylinder 84 is pulled toward side bar 92,
thereby decreasing gap 90. Eventually, a pin member extending from
side bar 92 engages hole 88 in cylinder 84, causing rotation of
cylinder 84 to lock. The surface of cylinder 84 is devised to
frictionally hold and resist slipping of the belt material around
cylinder 84 when rotation is locked.
[0041] Buckle 80 is preferably comprised of reliable and robust
design components to enable reproducible sling application to a
preset and safe tension level. Sling extensions 56a and 56b are
inserted through center portion 94 of buckle 80 and reverted by
means of cylinders 84. Cylinders 84 have a rough outer surface to
provide a high friction interface for engaging sling extensions 56a
and 56b. Cylinder 84 rotates with low friction on a polyethylene
roller core (not shown). The roller cores can slide laterally on
parallel guide rods 100. FIGS. 8-10 show cross-sectional views
through the sling of FIG. 7, illustrating the mechanism for locking
rotational movement of cylinder 84. Lateral translation of cylinder
84 on guide rod 100 in direction 102 causes lock pin 104 to engage
holes 88 in cylinder 84, disabling further rotation of cylinder 84.
This in turn disables further sling tensioning due to the high
friction interface between sling extension 56b and the outer
surface of cylinder 84. This feature of the sling device
automatically and reproducibly sets the tension of the sling at a
predetermined level. The preset tensioning level is in the range of
150 N to 250 N, preferably 200 N.
[0042] Once the sling tension level is reached, lock pin 104
engages hole 88 on cylinder 84 and enters a second sinkhole of
bigger diameter in cylinder 84. Lock pin 104 has a widened tip
portion that engages the inner lumen of cylinder 84. Thus, even if
the applied sling tensions decrease somewhat, cylinder 84 is not
able to slide off lock pin 104, since cylinder 84 will impinge the
widened tip portion of lock pin 104. Only if the applied sling
tension decreases substantially will cylinder 84 be pushed off lock
pin 104 by means of compression springs illustrated in FIG. 11.
This design feature, referred to as "locking hysteresis," makes it
possible to maintain the preset sling tension, even if the applied
tension to the sling extensions decreases. An emergency technician
can affix the ends of sling extensions 56a and 56b to the lateral
sling portions without the need to maintain full sling tension for
a prolonged amount of time, and without losing the preset sling
tension.
[0043] FIG. 11 shows another cross-section through buckle 80 of
FIG. 7. Compression spring 110 counteracts lateral translation of
cylinder 84 along guidepost 100. Compression spring 110 is mounted
over guide rod 100, between side bar 92 and cylinder 84, and is
covered by spring cage 112. This design component allows guided
lateral translation of cylinder 84 against a pair of compression
springs 110, only one of which is shown in FIG. 11. Collar 114 is
located on the center region of guidepost 100. Collar 114 can plant
rigidly to any site on guidepost 100 via screws. Collar 114 is used
to hold each cylinder 84 in a laterally translated position, at
which spring 110 is compressed to a preset value, for example 75 N
for each compression spring. Therefore, cylinder 84 will maintain
its position during sling tensioning up to the preset force value,
while sling extensions 56a and 56b are pulled over the respective
rotating cylinders. Only if the sling tension exceeds the preset
value, will lateral translation of cylinder 84 be induced.
[0044] The sling buckle described above is fully symmetric,
enabling sling buckle application in any orientation, therefore
minimizing potential complications in its application. The sling
buckle components are preferably designed to be fabricated from
non-metallic, radiolucent materials, excluding the cylinders, lock
pins, and compression springs. This enables radiographic
examination while maintaining pelvic reduction and
stabilization.
[0045] The sling design constitutes two distinct components, the
sling and the sling buckle, which are combined in a functional unit
with minimal effort. Different size-specific slings may be used
with the same buckle. Furthermore, it may be desirable to provide a
sling device in which the belt component is disposable and the
buckle is reusable.
Sling Location
[0046] An optimal sling location has been found to be within a
transverse plane at the level of the greater trochanteric region,
just proximal of the pubis symphysis. Application of a sling
further distally is not feasible from a clinical perspective,
disabling vital access to rectal and genital regions and the
femoral artery. Application of a sling further proximally results
in a significant decrease in the amount and quality of pelvic
reduction corresponding to constant amounts of sling tension. FIG.
12 is a bar graph showing the results of an experiment to determine
which sling location required the least sling tension to achieve
pelvic reduction in different fracture scenarios. The graph shows
that distal sling application, i.e., at the level of the
acetabulum, required the least sling tension to achieve pelvic
reduction in each of four different fracture scenarios: partially
stable, unstable, partially stable and hemorrhaging, unstable and
hemorrhaging.
Sling Tension
[0047] FIG. 13 shows a bar graph illustrating the results of an
experiment to determine the relationship between sling tension and
symphysis gap reduction. A sling tension level of 200 N was
required to reduce the pelvis sufficiently, i.e., symphysis gap of
less than 10 mm.
[0048] FIG. 14 shows four CT images of a fractured pelvis. FIGS. A
and B show the fractured pelvis prior to sling-induced reduction.
The pelvic ring disruption is apparent by a widened SI joint in
image (A) and a symphysis gap of 50 mm (B). As shown in images C
and D, sling tension at the acetabular level at a tension of 200 N
resulted not only in the most efficient translation of the applied
sling tension into pelvic reduction, but also yielded the best
quality in reduction.
[0049] Although the invention has been disclosed in its preferred
forms, the specific embodiments thereof as disclosed and
illustrated herein are not to be considered in a limiting sense,
because numerous variations are possible. As used herein, singular
terms do not preclude the use of more than one of the associated
element, and embodiments using more than one of a particular
element are within the spirit and scope of the invention.
Applicants regard the subject matter of their invention to include
all novel and nonobvious combinations and subcombinations of the
various elements, features, functions, and/or properties disclosed
herein. No single feature, function, element or property of the
disclosed embodiments is essential. The following claims define
certain combinations and subcombinations of features, functions,
elements, and/or properties that are regarded as novel and
nonobvious. Other combinations and subcombinations may be claimed
through amendment of the present claims or presentation of new
claims in this or a related application. Such claims, whether they
are broader, narrower, equal, or different in scope to the original
claims, also are regarded as included within the subject matter of
applicants' invention.
* * * * *