the Texas A&M University Veterinary Medical Teaching
2
In 1958, a group of Swiss orthopaedic surgeons formed the AO foundation, also known as the Association for the Study of Internal Fixation (ASIF). They established principles for fracture management that helped standardize fracture treatment protocols for the human and veterinary community. Initially, the AO recommend- ed precise anatomic fracture reconstruc- tion (known as direct reduction) be performed prior to internal fixation for all fracture configurations. However, in highly comminuted fractures, which are common in veterinary patients, anatomic reconstruction requires extensive surgi- cal exposure, manipulation of fracture fragments, and additional injury to the supporting soft tissue envelope. Anatomic reconstruction must be accomplished by placement of interfragmentary cerclage wires or lag screws, followed by placement of a precisely-contoured bone plate. Recent advances in fracture manage- ment in humans have focused on mini- mally invasive fracture stabilization tech- niques. Previous work has shown the invasive approaches necessary for ana- tomic fracture reconstruction and direct reduction disrupt the fracture hematoma and the extraosseus blood supply, each of which slow bone healing. Based on these findings, the AO has adopted principles of biological osteosynthesis which maxi- mize healing by protecting the patient’s biology while at the same time accomplish biomechanical fracture fixation goals. The principles of biological osteosyn- thesis are: 1) Minimize iatrogenic soft tissue dis- ruption. 2) Utilize indirect reduction techniques (align the two major or parent fracture fragments in a functional position with- out anatomically reconstructing individu- al fracture fragments). 3) Provide stable fixation. 4) Promote the early return to limb function. NOTES surgery Vol. 1, No. 4 ~ Summer 2011 a quarterly publication of the small animal surgery service at the Texas A&M University Veterinary Medical Teaching Hospital Did you know? There are currently a number of locking plate systems available to veterinary sur- geons. At Texas A&M, we utilize the LCP (Synthes Vet, West Chester, PA), SOP (Or- thomed North America, Vero Beach, FL), and FIXIN systems (TraumaVet, Rivoli, Italy) when selecting a locking system for fracture repair. Only the FIXIN system contains a novel bushing-insert locking mechanism and is composed of both stainless steel and titanium components to more closely mimic the material properties of bone. MIPO factoids... • MIPO was developed as an internal fixation technique for achieving biological osteosynthesis • During MIPO, the fracture frag- ments are typically not exposed or visualized; instead, a plate is insert- ed through small incisions known as portals and tunneled along the fracture • MIPO results in an early return to function, a low incidence of complications, and rapid fracture healing Updates in fracture repair: Minimally Invasive Plate Osteosynthesis (MIPO) Figure 1: (Left) Immediate pre-op and post-op lateral radiographs of a fracture treated with MIPO. A FIXIN plate was used to stabilize this fracture. (Right) Intra-operative photo of a MIPO portal. The plate is placed from one portal, along the fractured bone, and out the other portal.
the Texas A&M University Veterinary Medical Teaching
In 1958, a group of Swiss orthopaedic surgeons formed the AO
foundation, also known as the Association for the Study of Internal
Fixation (ASIF). They established principles for fracture
management that helped standardize fracture treatment protocols for
the human and veterinary community. Initially, the AO recommend- ed
precise anatomic fracture reconstruc- tion (known as direct
reduction) be performed prior to internal fixation for all fracture
configurations. However, in highly comminuted fractures, which are
common in veterinary patients, anatomic reconstruction requires
extensive surgi- cal exposure, manipulation of fracture fragments,
and additional injury to the supporting soft tissue envelope.
Anatomic reconstruction must be accomplished by placement of
interfragmentary cerclage wires or lag screws, followed by
placement of a precisely-contoured bone plate.
Recent advances in fracture manage- ment in humans have focused on
mini- mally invasive fracture stabilization tech- niques. Previous
work has shown the
invasive approaches necessary for ana- tomic fracture
reconstruction and direct reduction disrupt the fracture hematoma
and the extraosseus blood supply, each of which slow bone healing.
Based on these findings, the AO has adopted principles of
biological osteosynthesis which maxi- mize healing by protecting
the patient’s biology while at the same time accomplish
biomechanical fracture fixation goals.
The principles of biological osteosyn- thesis are:
1) Minimize iatrogenic soft tissue dis- ruption.
2) Utilize indirect reduction techniques (align the two major or
parent fracture fragments in a functional position with- out
anatomically reconstructing individu- al fracture fragments).
3) Provide stable fixation.
4) Promote the early return to limb function.
NOTESsurgery Vol. 1, No. 4 ~ Summer 2011 a quarterly publication of
the small animal surgery service at the Texas A&M University
Veterinary Medical Teaching Hospital
Did you know? There are currently a number of locking plate systems
available to veterinary sur-
geons. At Texas A&M, we utilize the LCP (Synthes Vet, West
Chester, PA), SOP (Or- thomed North America, Vero Beach, FL), and
FIXIN systems (TraumaVet, Rivoli, Italy) when selecting a locking
system for fracture repair. Only the FIXIN system contains a novel
bushing-insert locking mechanism and is composed of both stainless
steel and titanium components to more closely mimic the material
properties of bone.
MIPO factoids...
• MIPO was developed as an internal fixation technique for
achieving biological osteosynthesis
• During MIPO, the fracture frag- ments are typically not exposed
or visualized; instead, a plate is insert- ed through small
incisions known as portals and tunneled along the fracture
• MIPO results in an early return to function, a low incidence of
complications, and rapid fracture healing
Updates in fracture repair:
Figure 1: (Left) Immediate pre-op and post-op lateral radiographs
of a fracture treated with MIPO. A FIXIN plate was used to
stabilize this fracture. (Right) Intra-operative photo of a MIPO
portal. The plate is placed from one portal, along the fractured
bone, and out the other portal.
Texas A&M’s Veterinary Medical Teaching Hospital continues it’s
fixed price program for common surgical diseases.
Uncomplicated appendicular fractures - $2000
Surgical eligibility requirements:
1) Single, appendicular fractures with a maximum duration of 7-10
days prior to admission. Radius/ulna and tibia/fibula are
considered single frac- tures.
2) Systemically stable patient with no signs of head, thoracic,
abdominal, or spinal injury.
3) Closed fracture, or at most a grade I open fracture of less than
24 hours duration prior to presentation to the CVM.
Services include physical examina- tion, pre-operative bloodwork
and uri- nalysis, pre and post-operative radio- graphs, fracture
repair, hospitalization, medications, and early
rehabilitation.
By respecting the soft tissue envelope and using indirect reduc-
tion techniques, biological osteosynthesis techniques have led to
accelerated fracture healing, improved patient comfort and limb
use, reduced surgical time, and a lower incidence of post-
operative complications such as infections, delayed unions, and
implant failures.
Many veterinary fractures are excellent candidates for indirect
reduction using biological osteosynthesis techniques. Other frac-
tures, such as two-piece, transverse mid-diaphyseal fractures con-
tinue to be excellent candidates for direct reduction. It is impor-
tant to remember that even if direct reduction is selected for a
particu- lar fracture, many of the principles of biolog- ical
osteosynthesis may still be followed.
Application of a cast or an external fixator to a fracture using
closed reduc- tion techniques ac- complishes the goals of
biological osteo- synthesis. When used in appropriate cases,
external skel- etal fixation (ESF) is a highly successful and
versatile system for fracture repair (Figure 2, 4), and we continue
to use ESF regularly at Texas A&M. Unfortunate- ly, many
patients are not candidates for external skeletal fixation due to
fracture con- figuration, patient temperament, or client
compliance. Minimal- ly Invasive Plate Osteosynthesis (MIPO) was
developed as an in- ternal fixation technique in order to both
adhere to the goals of biological osteosynthesis and provide a
minimally-invasive alter- native to ESF. With MIPO, two small
incisions, or portals, are cre- ated along the proximal and distal
aspects of the injured bone, remote to the fracture fragments. The
parent fracture fragments are grasped through the portals, and the
fracture is aligned us-
ing indirect reduction techniques. Next, an epiperiosteal tun- nel
is made connecting the two portals, followed by insertion of the
plate through one of the portals, through the tunnel, and into the
other portal (Figure 1). Screws are then used to secure the plate
proximally and distally. Although MIPO is readily per- formed for
fractures in which there is little soft tissue coverage (tibia,
radius/ulna), it can also be performed successfully in the humerus
and femur. Because most of the fracture fragments are not directly
exposed or visualized, the MIPO technique can be technically
challenging, and it is not suitable for every fracture.
Surgeons at Texas A&M, through the mentorship of Dr. Don Hulse,
have been utilizing MIPO to treat our patients’ fractures for
several years, and our clini- cal experience has been very
encourag- ing. Most MIPO pa- tients are extremely comfortable and
will walk on the op- erated limb as early as 1-2 days post-op-
eratively. The inci- dence of infections, delayed unions, and
implant failures ap- pears to be lower than with tradition- al
fracture fixation techniques, and the fractures heal rapid- ly
(similar to a frac-
ture treated by closed application of an external fixator).
The recent shift toward biological osteosynthesis using MIPO have
led implant manufacturers to develop implants that func- tion more
as internal fixators than traditional bone plates. These novel
“locking” systems function in buttress mode and al- low each screw
to physically lock into the plate as well as engage the bone.
Locking a bone screw into a plate results in a small gap between
the plate and bone, which may protect the perios- teal blood-supply
and accelerate healing. Although we utilize a
Dr. Brian Saunders is a 2001 graduate of the Texas A&M
University College of Veterinary Medicine & Biomedical Sciences
(DVM) and a 2005 graduate of Texas A&M University Health
Science Center (PhD). After completion of a small animal surgical
residency, he joined the faculty as a Clinical Assistant Professor
in Or- thopedic Surgery in 2009. He is a member of the American
College of Veterinary Surgeons.
Dr. Saunders clinical interests include joint re- placement,
arthroscopy, CORA-based correc- tion of limb deformities, and
minimally inva- sive fracture repair. He has a strong research
interest, and is in the process of establishing a cell biology
laboratory to investigate molecular causes as well as molecular or
cell-based thera- peutics for common orthopedic conditions.
Visit the VMTH Small Animal Surgery Service on the web at
vetmed.tamu.edu/services/orthopedics
Dr. Brian Saunders
Eligibility...
• Financially responsible clients (able to leave the 50% down pay-
ment at time of admission) who will be responsible for post-op
after care and who agree upon initial treat- ment to return for
recheck examina- tions.
• Prices do not include hospitaliza- tion/rehab longer than 7 days,
or the cost of major complications or re-operations.
Faculty Spotlight: Dr. Brian Saunders
number of locking plate systems at Texas A&M, we are excited to
announce that we have recently begun using the FIXIN sys- tem
(TraumaVet, Rivoli, Italy). The FIXIN system is a locking system
that utilizes a novel bushing-insert system to lock the bone screws
into the bone plate (Figure 3). The bone plate is composed of
stain- less steel, but the bushings and screws are titanium alloy,
which gives the system ma- terial properties that more closely
mimic normal bone. The FIXIN system is offered in various sizes and
shapes, is competitive- ly priced when compared to other locking
systems, and is highly amenable to MIPO techniques.
Summary A paradigm shift has occurred in frac-
ture repair in which care for the soft tissue envelope and fracture
hematoma takes precedence over anatomic fracture recon- struction
using large, open approaches and direct reduction techniques. This
transition has led many orthopedists to operate with the mindset of
a gardener,
rather than that of a carpenter! Regard- less of whether an open
approach or MIPO is selected, or whether internal or external
fixation is selected, we continue to offer our fixed price package
for rou- tine appendicular fractures. We hope this update has been
helpful, and that you will continue considering Texas A&M when
contemplating referral of your fracture patients.
References:
1. Hudson et al, 2009, Vet Comp Orthop Trau- matology. “Minimally
invasive plate osteosynthesis: Applications and techniques in dogs
and cats.”
2. Witsberger et al, 2010, Vet Comp Orthop Trau- matology.
“Minimally invasive application of a ra- dial plate following
placement of an ularn rod in treating antebrachial
fractures.”
3. Guiot et al, 2011, Veterinary Surgery. “Prospec- tive evaluation
of minimally invasive plate osteosyn- thesis in 36 nonarticular
tibial fractures in dgos and cats.”
Figure 3: The FIXIN system is a new locking bone plate system that
uses a novel bushing-
insert system and is composed of both stainless steel and titanium
alloy. It is an ex- tremely versatile and effective system, and
amenable to MIPO or open techniques.
Figure 4: Immediate post-op and 8 week post- op radiographs of a
distal radius and ulna fracture treated with a “hybrid” external
fixator from same patient as Figure 2.