Harvesting of the Proximal Part of the Fibula
The aim of this procedure is the harvest of the proximal epiphysis and a
variable amount of the diaphysis of the fibula with use of the anterior tibial
artery and veins as a vascular
pedicle3,4.
This artery (Fig. 1) supplies
the epiphysis by means of a recurrent epiphyseal branch as well as the
proximal two-thirds of the diaphysis by means of tiny musculoperiosteal
branches, which must be carefully preserved during the dissection. During the
surgical exposure of the fibula, great care also should be taken to prevent
damage to the motor branches of the peroneal nerve and to the epiphyseal
vascular pedicle.
Because of its anatomical similarities with the distal part of the radius,
the proximal part of the contralateral fibula is preferred for reconstruction
following distal radial loss. The patient is placed on the operating table in
the supine position. The hip and the knee of the selected donor extremity are
flexed, and a sterilized tourniquet is applied. Since the dissection can be
difficult and time-consuming, the tourniquet should be inflated at the last
minute in order to take full advantage of the ischemia time, which should not
exceed two hours.
CRITICAL CONCEPTSINDICATIONS:A vascularized transfer of the proximal fibular epiphysis is indicated in
the reconstruction of the proximal part of the humerus and the distal aspect
of the radius in children. The procedure is appropriate for the treatment of a
tumor, congenital deformity, or traumatic injury. The longer the expected
period of time between surgery and the end of growth, the stronger is the
indication for this technique, which can provide substantial longitudinal
growth. The anatomical similarities between the proximal aspect of the fibula
and the distal aspect of the radius make this procedure particularly useful in
the reconstruction of this segment, especially when taking into account the
severe functional impairment that can result from the length discrepancy with
the adjacent ulna with other reconstructive options.CONTRAINDICATIONS:Anatomical variations of the vascular network of the leg represent the
major contraindication for this technique. Preoperative angiography
(Fig. 9) provides crucial
information regarding the epiphyseal vascular supply and is able to
demonstrate the recurrent branch of the anterior tibial artery and its
contribution to the blood supply of the proximal fibular epiphysis. With the
absence and/or hypoplasia of this branch, the procedure cannot be performed.
In addition, the anterior tibial artery cannot be harvested as the vascular
pedicle of such a graft in patients in whom this artery is the dominant
vascular supply to the foot.PITFALLS:Injury to the recurrent epiphyseal branch of the anterior tibial artery
during the dissection is the major technical mistake. To prevent this
complication, which substantially reduces the value of this procedure, a
direct dissection of the fragile epiphyseal vessels should be avoided and they
should be protected with a full-thickness muscular cuff consisting of the
proximal portion of the extensor digitorum longus and peroneus longus
muscles.In addition, the diaphyseal musculoperiosteal branches to the fibula are
very thin (Fig. 10), and they
cannot be dissected safely. Once again, a certain amount of soft tissue around
the pedicle, including the interosseous membrane (Figs.
11-A and 11-B) and a
longitudinal strip of muscle (Fig.
12) that contains the tiny perforator arteries to the fibular
periosteum, should be preserved.Finally, great care should be taken in dissecting the peroneal nerve from
the vascular pedicle. The motor branches to the anterior and lateral muscles
are quite thin and fragile and require a very tedious and gentle dissection.
If a motor branch is severed, it should be repaired with use of a
microsurgical technique.
CRITICAL CONCEPTS
INDICATIONS:
A vascularized transfer of the proximal fibular epiphysis is indicated in
the reconstruction of the proximal part of the humerus and the distal aspect
of the radius in children. The procedure is appropriate for the treatment of a
tumor, congenital deformity, or traumatic injury. The longer the expected
period of time between surgery and the end of growth, the stronger is the
indication for this technique, which can provide substantial longitudinal
growth. The anatomical similarities between the proximal aspect of the fibula
and the distal aspect of the radius make this procedure particularly useful in
the reconstruction of this segment, especially when taking into account the
severe functional impairment that can result from the length discrepancy with
the adjacent ulna with other reconstructive options.
CONTRAINDICATIONS:
Anatomical variations of the vascular network of the leg represent the
major contraindication for this technique. Preoperative angiography
(Fig. 9) provides crucial
information regarding the epiphyseal vascular supply and is able to
demonstrate the recurrent branch of the anterior tibial artery and its
contribution to the blood supply of the proximal fibular epiphysis. With the
absence and/or hypoplasia of this branch, the procedure cannot be performed.
In addition, the anterior tibial artery cannot be harvested as the vascular
pedicle of such a graft in patients in whom this artery is the dominant
vascular supply to the foot.
PITFALLS:
Injury to the recurrent epiphyseal branch of the anterior tibial artery
during the dissection is the major technical mistake. To prevent this
complication, which substantially reduces the value of this procedure, a
direct dissection of the fragile epiphyseal vessels should be avoided and they
should be protected with a full-thickness muscular cuff consisting of the
proximal portion of the extensor digitorum longus and peroneus longus
muscles.
In addition, the diaphyseal musculoperiosteal branches to the fibula are
very thin (Fig. 10), and they
cannot be dissected safely. Once again, a certain amount of soft tissue around
the pedicle, including the interosseous membrane (Figs.
11-A and 11-B) and a
longitudinal strip of muscle (Fig.
12) that contains the tiny perforator arteries to the fibular
periosteum, should be preserved.
Finally, great care should be taken in dissecting the peroneal nerve from
the vascular pedicle. The motor branches to the anterior and lateral muscles
are quite thin and fragile and require a very tedious and gentle dissection.
If a motor branch is severed, it should be repaired with use of a
microsurgical technique.
An anterolateral approach is used to isolate the proximal part of the
fibula on the basis of the anterior tibial arterial network (Figs.
2-A, 2-B, and
2-C). The dissection is carried
out in the intermuscular plane between the tibialis anterior and the extensor
digitorum longus muscles (Fig.
2-C). The neurovascular bundle is better exposed from distal to
proximal, since the dissection of the peroneal nerve from the anterior tibial
artery and veins is easier in the distal portion of the operating field
(Fig. 3-A). In the proximal
one-half of the leg, the nerve surrounds the vascular bundle in an intricate
three-dimensional pattern and sends many branches to the muscles of the
anterior compartment (Fig.
3-B). Some of these motor branches may perforate the space between
the vascular bundle and the bone and therefore cannot be dissected
(Fig. 3-C). In this case, the
motor branch is divided and then repaired with use of microsurgical
techniques.
In order to expose the fibula, the extensor digitorum longus muscle,
together with the peroneus longus muscle, is sharply detached from its
proximal insertion at the level of the emergence of the peroneal nerve into
the anterior compartment of the leg (Figs.
4-A, 4-B, and 4-C). The
proximal muscular cuff must be left attached to the fibular head since it
contains the recurrent epiphyseal branch of the anterior tibial artery on
which this transfer is based. During the diaphyseal dissection, as many
periosteal branches as possible are preserved. For this reason, it is
recommended that the interosseous membrane and a longitudinal strip of muscle
be harvested as well in order to protect the small branches from the main
artery to the diaphyseal periosteum of the proximal part of the fibula.
The fibula is resected and is separated from the surrounding muscles and
the peroneal artery, which is located in close proximity to the posteromedial
aspect of the middle and distal parts of the fibula. An extra portion of
periosteum (Fig. 5) should be
harvested so that it can overlap the osteotomy site of the recipient bone, to
enhance the bone-healing. The segment of diaphysis should not extend beyond
the proximal two-thirds in order to preserve an adequate vascular supply to
the periosteum.
The proximal tibiofibular joint is then opened, with care taken to preserve
as much of the lateral collateral ligament of the knee as possible. The biceps
femoris tendon is divided longitudinally
(Fig. 6), and the posterior
strip is incorporated in the graft in order to reinforce the soft-tissue
repair at the recipient site. The anterior half is sutured to the lateral
collateral ligament, which is going to be fixed to the lateral aspect of the
tibial metaphysis. Finally, the proximal dissection of the pedicle is carried
out until the origin of the anterior tibial artery is exposed and ligated. In
order to obtain a longer and more conveniently located pedicle, this graft has
been hemodynamically modified according to a reverse flow model. The long
distal portion of the pedicle is therefore preferred for anastomosis to the
recipient vessels. As has been reported in the
literature5 and
confirmed by our clinical experience, the venous flow can be reversed,
provided that the small shunts that interconnect the two venae comitantes are
preserved during the dissection of the vascular bundle. Usually, only one of
the two venae comitantes has adequate flow, and the surgeon should be aware of
which vein is the better choice for the anastomosis in the recipient site.
Care is taken when repairing the lateral structures that stabilize the knee
joint. The lateral collateral ligament, enhanced by the residual portion of
the biceps femoris tendon, is fixed to the lateral aspect of the tibia with
nonabsorbable sutures into the periosteum, and stability is evaluated. The
donor extremity is protected by an above-the-knee cast, which should be worn
for one month.
Reconstruction of the Distal Part of the Radius
Fixation of the proximal part of the fibula to the distal part of the
radius can be achieved either with a plate and screws
(Fig. 7-A) or with lag screws
if a step-cut osteotomy is performed. Either procedure is facilitated by the
similarity between the diameters of the donor and recipient bones. In the case
of a total resection of the radius, the fibula should be fixed, end to side,
to the ulna (Fig. 7-B) with lag
screws in order to achieve adequate stability. When the distal part of the
ulna has been resected as well, the fibula should be fixed to the residual
proximal part of the ulna to create a one-bone forearm
(Fig. 7-C).
The wrist is temporarily stabilized with a 1.2-mm Kirschner wire, which is
removed one month postoperatively. The strip of biceps femoris tendon
remaining attached to the fibular head is used for soft-tissue repair and is
anchored to the remaining distal radiocarpal capsule and ligaments
(Fig. 8). In contrast, the
distal radioulnar joint is usually left slightly lax in order to prevent any
possible impingement during pronation and supination.
A reverse-flow arterial end-to-end anastomosis is then performed with
either the radial artery or the common interosseous artery. The recipient vein
is usually the cephalic vein. At the end of the vascular repair, bleeding
should be observed from the muscular cuff surrounding the transferred proximal
part of the fibula. An above-the-elbow cast is worn during the first two
months postoperatively and is then replaced with a wrist splint.