Lower Extremity Rodding In OI: What Is New?

F. Fassier, MD
Associate Professor, Department of Surgery, Division of Orthopaedic Surgery, McGill University Health Center, Montreal Children's Hospital, Shriners Hospital for Children, Montreal, Quebec, Canada

In 1959, Sofield and Millar introduced the principle of multiple osteotomies and intramedullary rodding for the correction of deformities of long bones in OI. The technique was improved in 1963 by Bailey and Dubow who designed a telescopic rod elongating while the bone grows. Since then, several reports mention the advantages and the complications of using either a regular or a telescopic rod. The debate is not over yet!

In our experience, there is no difference in the complication rate using one or the other nail; but the re-operation rate is lower (27%) with telescopic nail compared to rigid nail (51%). Finally, 80% of the patients were walkers at follow-up compared to 44% prior to surgery (unpublished data).

What is new?

1. New Indications: The use of pamidronate has enlarged the indications of rodding to most type III patients. For the same reason, all types of OI treated at a very young age do progress so fast that the age for rodding is younger than before: 18 months to 2 years (causing problems for the size of rods).
2. New Global Approach: The team approach allows a faster rehabilitation of our patients. Post-operative immobilization is reduced to 3 weeks with early bracing and verticalization. The use of spica casts is very rare (less bone loss and weakness).
3. New Surgical Method: Limited approach to the bone to be rodded has significantly reduced the blood loss. Whenever possible (large bones, thin cortices) a percutaneous telescopic rodding is performed. Soft tissue trauma being limited, it results in less pain and stiffness post-operatively (as well as, small scars!).
4. The Future: An New Implant?: Most of the mechanical complications seen with the telescopic rod (migration/unscrewing of the "T" part) must be avoided. The ultimate goal is to rod long bones without opening the joints (as in adults).

The treatment of OI has really changed over the years due to a combined medical and surgical approach involving all aspects of this disease. Ultimately, will the rods still be necessary?

Reference: Proceedings of the 7th International Conference on Osteogenesis Imperfecta. Montreal, Canada, 1999.