– an alternative to limb amputation
Dr Michael Weber, a specialist in limb lengthening and reconstruction, has
moved his practice from Germany to the UAE because of the high demand for his
services in the Arab world. Callan Emery speaks to the orthopaedic surgeon about
A German doctor who specialises in limb
lengthening and reconstruction has relocated
his practice from Germany to the
United Arab Emirates because of the high
demand from this region for his expertise.
Beside limb deformities acquired largely
through trauma, the prevalence of limb
deformities of congenital origin is considered
to have a relatively high prevalence
in the Arab world – due in large part to the
high number of consanguineous marriages
– although accurate figures are not readily
Dr Michael Weber, MD, PhD, a Professor
of Orthopaedics and faculty member of the
RWTH University in Aachen, Germany,
uses an ingenious technique to lengthen
limb bones called ‘distraction osteogenesis’.
The procedure was pioneered 50 years ago
by a Russian orthopaedic surgeon, Gavril
Abramovich Ilizarov and offers a favourable
alternative to limb amputation.
“These techniques can be used with
patients of all ages from newborn to the
elderly,” Dr Weber said. “The oldest
patient I have operated on was 71. The
surgery is minimally invasive, using highly specialised equipment.”
He explained that the lengthening and
reconstruction of limb bones is an expensive
procedure and that recent German
government regulations restricting what he
could charge patients meant that in many
instances the devices required for the treatment – such as the Taylor Spatial
cost more than he was allowed to charge for
As more than 30% of his patients came
from the Arab world he was motivated to
relocate his practice from Germany to the UAE where he established the Center for
Limb Lengthening and Limb Reconstruction
at the American Hospital Dubai.
For a more than a year, Dr Weber has
directed this new centre, the first of its
kind in the UAE, where he receives
patients from across the UAE, the wider
region and Europe.
Speaking to Middle East Health, he was
quick to point out that it was not only
congenital factors that were responsible
for limb deformities in the region. “Car accidents, for example, also account
many limb deformities, as well as weak
bones resulting from vitamin-D deficiency
due to a lack of exposure of the
patients’ skin to the sun,” he said.
Although Dr Weber uses the distraction osteogenesis technique pioneered by
Dr Ilizarov, he has himself developed a
number of new techniques – such as the
‘Weber-Cable-Technique’ – which enable
this procedure to be used for a wider range
of indications. The Weber-Cable
Technique is used as a salvage procedure
for bone defects.
For those who can afford it, it is a lifechanging
treatment enabling those who
had been unable to walk or use one of
more of their limbs, to do so again – or in the case of many paediatric
patients, to do
so for the first time.
Highlighting the extent to which this
technique can be use to lengthen a
deformed limb, Dr Weber pointed out that
he lengthened the leg of one of his paediatric
patients by as much as 22 cm to match
the length of the other leg and enabling the
patient to walk properly for the first time.
“In some parts of the world, like the US,
where the treatment is very expensive,
those who can’t afford it simply have their
affected limb amputated,” he said.
He believes this happens a lot in this
region as well, but not because they can’t
afford the treatment, but rather because
they don’t know it exists.
To this end, he has been involved in a
number of educational seminars across the
region, teaching other orthopaedic surgeons
about this technique and how to use it.
Discussing the most recent weekendlong
course, he said that some 35 doctors
from Iran, Jordan, Oman, Saudi Arabia,
Kuwait, Libya and the UAE attended. He
said the course should be sufficient for
them to start using some of these techniques
provided they had sufficient experience
in orthopaedic surgery.
Taylor Spatial Frame
Dr Weber points out that the technology
supporting distraction osteogenesis
continues to evolve. The most advanced
external ring fixator to date is known as
the Taylor Spatial Frame (TSF).
The TSF consists of two aluminium
rings connected by six struts. Each strut
can be independently lengthened or
shortened. Connected to the bone by
wires or half pins, the attached bone can
be manipulated in six axes (anterior/
posterior, varus/valgus, lengthen/
shorten.) Angular, translational, rotational,
and length deformities can all be
corrected simultaneously with the TSF.
Using computer analysis in 3D the TSF's
unique parallel kinematics enables all six
degrees of geometric freedom. This gives
the surgeon complete freedom to
correctly orient and align the broken
The TSF is used in both adults and
children. It is used for the treatment of
acute fractures, mal-unions, non-unions
and congenital deformities. It can be used
on both the upper and lower limbs.
Once the fixator is attached to the
bone, the deformity is characterised by
studying the postoperative x-rays. The
angular, translational, rotational, and
length deformity values are then entered
into specialised software online, along
with parameters such as the ring size and initial strut lengths. The software
produces a “prescription” of strut changes
that the patient can follow. The struts are
adjusted daily by the patient until the
correct alignment is achieved.
Correction of the bone deformity can
typically take 3–4 weeks. Once the deformity
has been corrected, the frame is
then left on the leg till the bone heals.
This often takes 3–6 months, depending
on the nature and degree of deformity.
Limb bone deformities requiring surgery can
be either inherited or acquired. Congenital
limb bone malformation has a relatively
high prevalence in the Arab world gauging
by the large number of these types of deformities
that Dr Weber sees.
“Congenital deformities account for
about 70% of my patients [in the Arab
world],” Dr Weber said. The most common
of which he treats are fibular hemimelia
(the partial or total absence of the fibula),
tibial hemimelia (the partial or total
absence of the tibia), and congenital tibial
In the “acquired” limb deformity category,
deformities generally arise from non
union of the bones after trauma, infection
of the bone and vitamin-D deficiency.
“I treat a lot of congenital malformations
as well as many acquired deformities
from trauma injury when the bone doesn’t heal properly,” he said.
Following the diagnosis, treatment
involves the use of one a number of ring fixator devices, such as the mini ring fixator,
the Ilizarov apparatus, the Taylor Spatial
Frame, or motorised nails, such as the
Fitbone nail. All of these have specific indications
The intramedullary nail
An alternative to the external ring
fixator device is the intramedullary rod or
nail. It is an internal device that is
implanted in the intramedullary canal of
a surgically fractured longbone. There is a
motor inside the nail with an antennae
attached which is implanted under the
skin. With a remote device the patient
can activate the motor within the nail
via the antennae to lengthen the nail
gradually and so steadily increase the
length of the bone as it continues to grow to heal the fracture.
Dr Weber says his surgery has exclusive
right to the Fitbone nail in the UAE.
The Fitbone nail has several advantages:
•There is no connection through the skin
•No need for pin site care - and no pin
•The scarring is minimal
•The patients have less pain
It is essential that this procedure is
carried out by an expert orthopaedic
surgeon as there is a risk of severe bone
infection and other complications like
contractures of joints if the pins are
not fitted correctly or the postoperative
management is not appropriate.
Complications of Ilizarov leg lengthening:
a comparative study between
patients with leg length discrepancy
and short stature.
– B. Vargas Barreto, et al.
Int Orthop. 2007 October;
Lengthening the bone
There are a range of
ring fixator devices;
however, the procedure
for using these
devices is similar.
After thorough measurements
required length and
correct positioning of
the limb there is an
initial surgery, during
which the bone is
and the external ring
apparatus is attached
with pins penetrating
the soft tissue and into
the bone – one part to
the distal portion of
the bone and the other
the proximal segment.
After 7 days the bone
begins to form a fracture
callous and the
fractured bone begins
to grow together.
While the bone is
growing, the frame is
adjusted at regular
intervals by turning a set of screws which gradually increases
the space between the two rings and thus
the proximal and distal portions of the
bone are slowly drawn apart (distraction)
while the fracture callous continues to
grow between the two – in a sense
tricking the bone to continue growing.
This is distraction-osteogenesis.
“This is a natural process,” Dr Weber
explained. “You always have a weaker and
softer area in the middle of the callus so
this is why you can do the lengthening.
And all the surrounding tissue – nerves, muscle, tendons – grow with the bone as
it is being lengthened – the same process
as in a growing child.”
He said that the bone grows at a rate of
about 3 cm per month.
“We always use some form of fixator
device. However, we prefer to use the
external ring fixator because it provides
the best correctability of the deformities,
the best mobility for the patients with full
weight bearing and has all the different
sizes we need for paediatric to adult
patients,” Dr Weber explained. “Once the
frame is fitted, the patient can walk around
and lead a pretty much normal life. The
patient will generally wear it for several
months, depending on the length of new
bone that’s required.”
As an alternative of the external fixator
the implanted motorised intramedullary
fitbone nail can be used for lengthening.
When the bone growth has reached the
required length and the fracture callus
completely maturated, the frame is removed
and the treatment is complete.
Long-standing question in bone biology answered
A long-standing question in bone
biology has been answered: It is the
spindly extensions of bone cells that
sense mechanical stimulation and signal
the release of bone-growth factors,
according to research from The
University of Texas (UT) Health
Science Center at San Antonio.
The study, reported recently in
Proceedings of the National Academy of
Sciences of the United States of America,
offers an important clue for developing
therapies to treat the bone-thinning
disease osteoporosis and bone loss associated
with aging, said Jean Jiang, PhD,
senior corresponding author from the
Department of Biochemistry, UT
Health Science Center Graduate
School of Biomedical Sciences.
“Osteocytes are the most abundant cells in
bone,” Dr Jiang said. “In the field of bone
biology, there was a long-standing debate
as to which part of the osteocyte senses mechanical loading. In this study, we
demonstrate for the first time that it is the
extensions, which are called dendrites.”
Regular physical exercise is highly beneficial
in maintaining bone health and in
prevention of bone loss and osteoporosis.
Mechanical stimulation of the bone
through weight bearing is critical for
promoting bone remodeling, said Sirisha
Burra, PhD, lead author from the
Department of Biochemistry.
“Maintenance of bone health depends
on the osteocytes’ ability to sense the stimulation,”
Dr Burra said. “If osteocytes lose
this ability, it could possibly lead to
diseases such as osteoporosis. Hence, it is
important to understand this mechanism.”
The Health Science Center collaborated
with Southwest Research Institute in San
Antonio to estimate the mechanical
impact of force applied to the dendrites.
Magnitudes of mechanical stress were
“Understanding how bone cells sense
and respond to mechanical signals within
the skeleton is an inherently multidisciplinary
problem,” said co-author Daniel P Nicolella, PhD, institute engineer in the
Mechanics and Materials Section at
Southwest Research Institute. “We determined
the mechanical stresses applied to
the osteocytes in these experiments so that
they can be compared to the mechanical
signals predicted to occur within the
skeleton during routine physical activities.”
Apart from its clinical implications, the
study is intriguing because it “brings in a
novel thought that different parts of a
single cell can have different material
and sensory properties,” Dr Jiang said.
“Different parts of the cell can react
differently to the same stimulus. This is a
very important fact to consider while
studying cellular signaling and regulatory
● Citation: doi: 10.1073/pnas.1009382107
of upload: 25th Sep 2010