2.11.1 Introduction

The concept of minimally invasive osteosynthesis (MIO) is not new. Closed intramedullary nailing, the percutaneous fixation of fractures using screws and K-wires, the application of external fixators, and use of bridging plates have all been performed using minimally invasive techniques for many years. However recent developments in implants, particularly the introduction of locking plates, have made MIO much more widely applicable than has been the case in the past.

The increasing trend toward indirect reduction of a fracture under image intensifier control, preservation of the fracture hematoma, and minimizing soft-tissue damage is logical since we know that the most important factor in achieving fracture union is preservation of the blood supply to the fracture fragments and adjacent soft tissues. It is, however, important to recognize that a small incision is not the same as a well-performed and planned operation, and that poorly performed MIO will have a much worse outcome than well-performed surgery done through a much larger incision.

This chapter looks at trends in the use of MIO, in particular minimally invasive plate osteosynthesis (MIPO) and some of the newer techniques and instruments that have been developed to facilitate it.

2.11.2 Indications for minimally invasive osteosynthesis (MIO)

Fractures can be broadly divided into those which require anatomical reduction of the fracture fragments and fixation with implants which achieve absolute stability and the rest, most of which can be managed by restoration of the correct length, axis, and rotation. These fractures do not require strict anatomical reduction of all fracture fragments. These fractures are then usually fixed with implants which provide relative stability, allowing them to heal with callus formation.

Whether and how an open or closed articular fracture can be accurately reduced is largely dependent on the complexity of the fracture. Simple fractures may be reduced and fixed with percutaneous lag screws using a minimally invasive technique. This always needs to be done under image intensifier guidance, and sometimes augmented by arthroscopy, particularly in the knee joint. Complex articular fractures almost always need accurate reduction under direct vision before fixation.

In diaphyseal fractures, as long as the joint at each end of the bone is correctly rotated and aligned and the bone has the correct length, the exact position of the fracture fragments is not as important as maintaining a good blood supply to the bone. Recognition of this fact has been responsible for the trend away from open plate fixation of shaft fractures toward the use of locked intramedullary nails, external fixation, and bridge plating.

From the mid-1990s surgeons began to combine the two concepts of fracture reduction in fractures that had both intraarticular and extraarticular components, reducing and fixing the articular portion under direct vision, while using minimally invasive bridge plating for the extraarticular component, leaving this segment of the fracture unexposed. As the concept has become increasingly popularized, implants that make it easier, such as locking and then contoured locking plates, have been developed together with appropriate instrumentation.

2.11.3 Minimally invasive plate osteosynthesis (MIPO)

MIPO is not a new technique; surgeons have long recognized the benefit of inserting conventional plates as bridging plates through small incisions outside the zone of injury after reducing the fracture by indirect methods. This technique has gained acceptance both because of the appreciation that minimizing soft-tissue damage preserves blood supply to the injured bone, and because it is possible with conventional plates. The introduction of locking plates has widened the scope and range of its application especially in osteoporotic bone.

Some surgical tips for MIPO are presented here. These are intended to be generally applicable. Information on how to use the technique for specific fractures are detailed and illustrated in section 3 of this book.

Planning positioning and approach

Detailed planning of any MIPO procedure is mandatory. The fracture will not be opened during surgery. The type and length of the plate, method of reduction, need for special instruments to achieve it, the plate insertion site, technique, and position, as well as the order of any screws, has to be determined from scaled x-rays preoperatively.

Most cases are performed with the patient supine on a radiolucent table to enable fracture manipulation under image intensifier control and accurate intraoperative assessment of limb alignment. It is tempting to use a fracture table to maintain the length and the rotation of the limb but this can make intraoperative assessment of the limb alignment difficult.

Two separate incisions are made over the intact bone each side of the fracture, preferably outside the zone of injury. The soft tissues are dissected down to the periosteum, which is left intact. The plate is then inserted subcutaneously or submuscularly over the periosteum, either after preparing a tunnel with a tunneling instrument or by using the plate itself (2.11-1).

Related posts:

2.9 Multiple fractures/polytrauma patients 2.7 Diagnostic methods 2.5 Diaphyseal fractures 2.1 Fracture issues 2.10 Reduction techniques 2.4 Instrumentation(2.4.4 – 2.4.6)

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