what-when-how
In Depth Tutorials and Information
FIGURE 47.5
Telescoping of the rods in the left femur is evident comparing the initial postoperative radiograph to a follow-up radiograph 4
years later. The female and male Fassier-Duval nails remain anchored appropriately in the greater trochanter and the distal epiphysis.
no difficulty retrieving the locked rods if rod revision
was necessary.
1
In addition to rod disengagement, there are many
complications seen after rodding in OI patients, and in a
recent series 60% of rods were no longer telescoping at
2 years, and 36% had been revised.
2
Rods can migrate
though the bone as well as subside inside the bone. Rods
can be bent during an acute fracture and may need to be
replaced in order to achieve fracture reduction.
Indications for surgical intervention are correction of
deformity, acute treatment of a fracture or prevention of
further fractures in a bone that has fractured in the past.
The number of long bones to rod in a single setting var-
ies depending on surgeon and patient. Rodding bilateral
femurs and tibias in a single setting can be extremely
difficult for both the patient and the surgeon; particu-
larly if there are multiple sites of significant deformity
in each bone creating the need for multiple osteotomies.
Rehabilitation is typically easier in the ambulatory child
when they can bear weight on a non-operative limb so
rodding an ipsilateral femur and tibia and returning to
the operating room to rod the other side when the child
is rehabilitated is often a plan that works well when four
long bones are under consideration for rod treatment. If a
femur is rodded first, a tourniquet can be safely applied
for use in the tibial rodding if desired - thus consider-
ation of rodding from proximal to distal is helpful.
Although telescopic rods are usually preferable, some
bones can be deceptively small in terms of the intra-
medullary canal size. In a study by Chotigavanichaya
et al.,
18
the geometry of the triangular tibial shaft can
make the prediction of the canal diameter difficult.
Often the long bones in severe OI are flattened, and
while in one plane the canal may appear large, in the
other plane the bone is quite thin and unable to accept
standard size telescoping intramedullary rods. Having
a backup solid rod available at the time of any surgery
is always helpful in the event that a telescopic rod is
unable to be safely placed in the canal. In addition, pas-
sage of a guide wire or reamer in the intramedullary
canal can be technically challenging. The intramedul-
lary canal is often poorly formed, and a space for the
rod may need to be created with careful, slow ream-
ing under fluoroscopic guidance. Occasionally the only
way to create an intramedullary canal in some sections
is to osteotomize the bone and expose the bone ends
for direct drilling and reaming. A commonly employed
technique is to use minimally invasive incisions and
fluoroscopy to place a guidewire into the starting point,
and then advance the guidewire carefully under luo-
roscopic guidance until it reaches the apex of defor-
mity in the long bone. A reamer is then placed over
the guidewire and reaming is carried out to the apex
(
Figure 47.6
). A small incision is then made at the apex,
and with minimal soft tissue disruption an osteotomy is
created with multiple drill holes and an osteotome. The
guidewire is reinserted and then advanced across the
osteotomy until another deformity apex is encountered,
and if so the process is repeated. This continues until the
guidewire can be passed from entry point into a central-
ized position in the distal epiphysis. Reaming over the
guidewire is done carefully under fluoroscopic guid-
ance to ensure the reamer stays inside the bone, and
reaming is not done across the physis.
