Spinal surgery

Spinal surgery


Collaborative work between spinal orthopaedics and
neurosurgery to develop existing but relatively new
technology has advanced our ability to undertake
much more complex procedures. The advances have
been made in the techniques of stabilisation. Some
previously unresectable lesions were unresectable sim­
ply because their removal meant there was nothing left
to carry out the vital spinal function of support. Now,
both the vertebral body and spinal canal can be excised
radically without fear of leaving the patient with too lit­
tle vertebral bone.


The most important adoption from our orthopae­
dic colleagues has been the use of pedicular screw fixa­
tion systems. In these, adjacent lumbar or thoracic
vertebrae are held together by rods fixed rigidly to
large cancellous bone screws which are introduced into
the vertebral body down the pedicle. This procedure,
originally developed in the 1980s for fixation of scolio­
sis, has been extended to treat other conditions such as
tumour instability.We do not yet
know whether pedicular screw fixation systems will be
useful for spinal fusion to relieve back pain in cases
where the indications for surgery are contentious.
Similar posterior fixation systems, called lateral
mass plates, are available for the cervical region.

There is also a wide variety of anterior fixation systems for
the whole spine which either replace the vertebral body
(such as with metal cages) or hold them together (cer­
vical body plates and screws). For the cranio­cervical
junction, there are several complex devices that
stabilise rheumatoid instability and fractures. Although
these procedures have been available in some units for
a few years, it is their wider use in most neurosurgical
units in the relatively infrequent complex spinal cases
that has occurred in the past two to three years.
With all these spinal implants, the preferred metal
is titanium which does not degrade the magnetic reso­
nance image badly so that details of the spinal cord can
be seen. It is worth remembering too, that metal is like
scaffolding around a building, it is only temporary.
Long term fixation depends on bony fusion. Without
fusion, the metalwork will always work free given time.

Trans­sphenoidal pituitary surgery

Trans­sphenoidal pituitary surgery


Possibly the most exciting development in neuro­
endoscopy is in trans­sphenoidal pituitary surgery. The
resection of an extension of a pituitary adenoma into
the cavernous sinus has been technically difficult up to
now as the tumour lies outside the operating field. Side
viewing endoscopes can see round this corner. This
should improve the success rate of surgery for
hormone secreting tumours, which demand complete
tumour removal for cure. This method of surgery is
called endoscopically assisted surgery because it is sim­
ply added on to the existing procedure. Some surgeons
are experimenting with the trans­sphenoidal proce­
dure carried out entirely through the endoscope. This
disturbs tissues even less, although it does not seem to
shorten the patient's stay in hospital. Whether the
results of this form of surgery will be as good as those
of standard surgery in both endocrine and visual terms
remains to be seen. Cure rates of about 75% for
hormonal disturbance and 80% for improvement of
vision can be expected with standard surgery.