Rodding in OI

The Official Alexi Soraya Site

Sometimes children with Osteogenesis Imperfecta undergo rodding surgery to help provide strength to their long bones (arms and legs). Rodding surgery involves inserting a metal rod into the bone to give it support, the rod acts as an internal splint. If a particular bone is bowed and/or has fractured repeatedly many parents begin thinking about having the bone rodded.

In the surgery the bone is cut in one or more places, this is called an osteotomy, and allows the bone to be straightened. Then a rod is inserted into the bone. Often times once a bone is straightened and has the added support of the rod it is able to tolerate more weight and movement than in the past. Many parents find that once a bone is rodded it does not break as easily. The rod may not always prevent the bone from breaking, but it will act as an internal splint that holds the bone in place, keeping it aligned, and greatly reducing the pain caused by a fracture. Most often a cast is not needed.

When to have rodding surgery depends on a number of things. If the bowing in a particular bone is greater than 30 degrees most doctors agree that it is not a question of "if" the bone will break, but rather "when". If the bowing is severe enough it may also interfere with a childs ability to learn to push up, crawl or stand. And in other instances a bone may fracture repeatedly, leading to a vicious cycle of a fractured bone being splinted, during which time it becomes weaker because of inactivity, then after it is healed it quickly fractures again which requires more splinting, leading to even greater weakness, etc.. Rodding surgery can help break this cycle and allow a child to use their limbs with much greater confidence.

Rodding surgery can either be planned or happen emergently because of a bad fracture. If your child has moderate to severe bowing or has had repeated fractures of the same bone, it is a good thing for the parents to talk with a doctor about rodding. If the surgery can be done locally sometimes the doctor and parents come up with a plan to wait for the next fracture and then rod at that time so as to minimize the childs "down time". If the surgery will not be done locally then more often this requires planning the surgery in advance.

In the past many surgeons did not want to rod very young children, but this has changed dramatically in the past 5-10 years because of Pamidronate treatments. Pamidronate can dramatically decrease bone pain (a general achiness that causes pain and prevents a child from wanting to move as much), decrease the fracture rate, and increases bone density. As a result babies and children with OI are moving more and reaching major milestones (rolling, sitting, crawling, standing, walking, etc) earlier than in the past. And because Pamidronate increases bone density the quality and size of bone that the surgeon has to work with is often greatly improved. For many children with OI, Pamidronate treatments, rodding surgery and physical therapy provide a very powerful combination, helping the child to reach their greatest potential for function and mobility.

What types of Rods are available?

There are two types of rods, Non-expanding and expanding rods.

Non-Expanding rods are very versatile, and are made in many sizes. They are inserted to support the full length of the long bone. In some cases, the rod is advanced across the growth areas, which are near the ends of the bone, to provide better support. The smooth surface of the rod does not reduce the growth of the bone. However, this type of rod does not grow with the child, and may need to be replaced as the bone grows if bowing occurs beyond the point where the rod endsThe rods are typically named for the person/s who developed them. The following is a brief description of three different rods that are often used in rodding surgeries.

Expanding rods consist of a smaller rod inserted into a larger hollow rod (like a telescope). They can lengthen as the bone grows, which may prevent the need for replacement. However, they are thicker than non-expanding rods, and are therefore only appropriate for larger bones, such as the femur (thigh bone). The bone must also be strong enough to allow the rod to be “anchored” at either end, and this type of rodding surgery requires incisions around the joints.

The Rush Rod is a Non-Expanding rod. It is straight with a small hook at the top and is inserted from the top of the bone downward. The Rush Rod is simple in design and has a low complication rate. It does not grow with the child and usually has to be replaced as frquently as every 15-24 months depending on the bone and growth rate of the child.

The Bailey-Dubow (B-D) Rod is an Expanding rod. It offers the benefit of lasting longer than non-expanding rods. They can lengthen as the bone grows, which may prevent the need for replacement. This type of rodding surgery requires incisions around the joints(including the knee). B-D rods are not anchored with screws into the ends of the bones so may pose a greater problem with migration of the rods then F-D rods.

The Fassier-Duval (F-D) rod is the newest of the rods. It is an Expanding rod and is seems to offer the greatest advantages for OI children. The procedure to insert the rods is much less invasive, can be done under the skin with smaller incisions than procedures for other rods. There is no need to open up the knee for femur rods which decreases recovery time. This equates to less blood loss, less soft tissue destruction and pain, smaller incisions, quicker recover time and fewer complications. The Fassier-Duval rod requires only 3 weeks of immobilization in long leg splints, rather than a hip spica (half body cast).