Minimum Invasive Plate Osteosynthesis in Canines
Richa Chourasia and Anita Kumari
PhD Scholar, College of Veterinary and Animal Sceinces, RAJUVAS, Bikaner
Corresponding author: chourasiaricha.27@gmail.com
Musculoskeletal system is the key system for providing support to the body, protecting soft tissues and is responsible for the locomotion. In companion animals the dysfunction or disorder of musculo-skeleton system is very common and amongst which fracture makes up the major part. Fracture in general is termed as complete or incomplete breakage of continuity of bone. Usually bone is surrounded by various muscles, blood vessels and nerve; so fracture is always accompanied by the various degree of damage to these structures.
Orthopaedic injuries should be treated as soon as possible if the patient is stable. Delay in fracture stabilization longer than 48 hours after injury is associated with a poorer functional outcome. The goal of fracture treatment is early ambulation and complete return of function. The principles of fracture treatment involves Anatomical reduction of fracture fragments, Stable fixation as per biomechanical and clinical situations, Preservation of blood supply to the bone fragments and surrounding soft tissues through atraumatic reduction and surgical technique and Early active pain free mobilization of muscles and joints adjacent to the fracture to prevent development of fracture disease. Bone fractures in dogs are amenable to various surgical and non-surgical intervention options. Numerous options ranging from external to internal fixation, casting, rest and amputation are available for choice.
Minimum invasive plate osteosynthesis (MIPO) is a procedure in which reduction and fracture fixation is done with direct exposure to the fracture site. Small skin incisions are used to prepare an epiperiosteal, subcutaneous, or submuscular tunnel that allows one to insert and apply the plate to the fracture fragments. It was first introduced in humans by Brunner and Weber in early 1990’s. In veterinary practice it was introduced in last decade and now well accepted techniques in dogs, cats and horses. MIPO in canines has promising results as compared to conventional techniques in terms of healing and with lesser complications. For the application of this technique Locking compression plates are considered as best option.
Advantages:
MIPO has many advantages like it limits the surgical dissection thereby preserving the fracture haematoma. Fracture haematoma provided many immune factors that are helpful in healing and act as anti-inflammatory factors. When less tissue is dissected and bone’s periosteum is least manipulated then there is maximum preservation of blood supply across the bone. All these factors provide optimal environment for early neovascularization.
General surgical considerations:
For the application of MIPO one must have a thorough anatomical knowledge of the fractured bone and the surrounding musculature, blood supply and nerve supply. Fracture fixation is done by giving the two incisions one on the proximal end of the bone and another on the distal end of bone. These two incisions are connected through a soft tissue tunnel which can be made by long blunt scissors or periosteal elevators. Bone alignment is maintained using indirect reduction methods like, hanging limb technique, bone holding forceps, IM pinning, fracture distractors, linear or circular external skeleton fixation and reduction through plate application. Since the fractured ends are not directly exposed, so it’s challenging to confirm/ maintain the reduction, for this the use of fluoroscopy becomes necessary. After reduction is maintained percontured locking plate is inserted through the tunnel and it is fixed on the proximal end first since it is easier to maintain the distal fragment. When the alignment is achieved the plate is also fixed on the distal end. Fluoroscopy is used for the confirmation of the alignment and implant positioning. Then the implant is fixed with bone with two bi-cortical screws one on both ends. Rest of the screw placement is as per the need and type of fracture.
MIPO in Humerus:
Best fracture for the application of MIPO in humerus is diaphyseal and metaphyseal fracture. Two lateral incisions are given on the bone for the application of lateral plate. Care must be taken while placing bi-cortical screws to avoid damage to the medial muscles.
MIPO in Radius and Ulna:
Orientation of plate placement through MIPO is similar to conventional plate placement.
MIPO in Femur:
Among the different fixation techniques for MIPO in femoral fractures, locking implants are especially valuable in proximal and distal metaphyseal fractures because of limited bone available for screw purchase and the risk for joint violation. When screws are placed close to the joint, mono-cortical screws can be useful to avoid joint penetration.
MIPO in Tibia:
Several advantages have to be considered in MIPO with locking implants in tibia and fibula fractures, especially when affecting the metaphyseal regions. In some large and giant breed dogs, the bone of the proximal metaphysis can be of poor density. This, in turn, may increase the risk of screw pull out. With locking implants, this risk can be reduced.
MIPO in Percutaneous Carpal and Tarsal Arthrodesis:
Locking plates have been successfully used to perform minimally invasive percutaneous plate arthrodesis in dogs. The features of locking plates such as lower rate of screw pull out and the limited need for contouring are also beneficial in percutaneous arthrodesis.
https://pubmed.ncbi.nlm.nih.gov/19448871/
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