Trans
-sphenoid operations:
 |
Craniopharyngiomas are lesions which have
provoked a lot of discussion as
regards their origin and treatment.
It has generally been accepted
that the best chance of obtaining
a cure is after total surgical
excision. |
Introduction
This goal has
been attained in only a small number
of patients because of the proximity
and sometimes, dense attachment of the
tumour to important neighbouring, neurovascular
structures. Persistent attempts at a
total excision in face of these problems
has led to some fatalities, and many
instances of severe post-operative morbidity.
This led to the concept of a safe, subtotal
excision, with postoperative radiation
therapy to the tumour residue, with
acceptable results. Excision of most
craniopharyngiomas has been correctly
carried out by the transcranial (mainly
subfrontal and fronto-temporral) route.
There have been a few reports of transsphenoidal
excision. Since 1982, 51 patients with
craniopharyngiomas, have been operated
and of these, 11 patients have had their
lesions excised by the trans-sphenoidal
route. These form the basis of this
communication.
Material
and method
The trans-sphenoidal
route for excision of pitutary tumours
was first used by us in 1982. Over the
ensuing six years, 140 transsphenoidal
operations were performed for pituitary
tumours and 11 patients with craniopharyngiomas
were operated by the trans- sphenoidal
route. Over the same period 40 patients
with craniopharyngiomas underwent surgery
by the trans-cranial route.
After recording the clinical signs and
symptoms skull X-rays and computed tomographic
(CT) scans were done in all patients
who underwent trans-sphenoidal surgery[11].
Carotid angiography was carried out
on the first two patients.
Surgery: The trans-sphenoidal approach
consisted of a sub- labial, rhinoseptal,
transsphenoidal entry into the sella.
The inferior part of the cartilaginous
septum was excised in the first 9 patients.
In the last 2 patients it was fractured
at its junction with the perpendicular
plate of the ethmoid, detached from
its attachment to the nasal floor and
dislocated to the right side. The bony
septum was excised. An opening, as wide
as possible was made in the sellar anterior
wall and floor. If the lesion was obviously
cystic (as judged by the CT scan), it
was aspirated trans-durally. The dura
was opened by a cruciate incision and
as much as possible of the tumour and
its capsule were excised. The sellar
hole was plugged with either auto or
homologous muscle graft, which was held
in place with a bony stent from the
nasal septum. The nostrils were packed
with vaseline gauze and the sublabial
incision was sutured.
The extent of excision performed was
graded as biopsy, sub-total excision
and total excision. This was based on
the operative impression alone. One
patient had only a biopsy done as the
tumour was very tough. During an earlier
sub-frontal operation done at another
insitute the prefixed position of the
optic chiasm precluded any excision.
Another patient underwent a trans-sphenoidal
operation without even the benefit of
a biopsy. This was due to the rock like
calcification of the tumour. At the
earlier sub-frontal operation, through
the lamina terminalis the cystic part
of the tumour was evacuated. Both these
patients had had ventriculo-atrial shunts
inserted to control the associated hydrocephalus.
In one patient lesion could be totally
excised. The tumour was predominantly
cystic with little calcification within
the capsule. In the remaining 8 patients
only a subtotal excision could be performed.
All these patients had large cystic
components with small calcified components.
Their cysts were evacuated and as much
of the capsule as possible was excised.
Only that part of the capsule that was
densely adherent to the sellar walls
was left behind. In some, the adherent
calcified part of the tumour had to
be left behind too.
Radiation Therapy: External radiation
with a Co60 beam was administered to
all except the last 2 patients who have
been operated only recently. Both these
patients will receive radiation therapy
as their excision have been sub-total.
Each of the other patients received
a total dose of 5000 rads. Even the
patients in whom the operative impression
was a total excision, was given radiation
treatment. This was because the possibility
of a small residue could not be entirely
ruled out.
Follow-up evaluation: This included
one or more neurological examinations
of 8 patients. The last 2 patients were
operated only 5 and 20 days ago respectively.
Follow-up in the earlier 9 patients
has ranged from 6 months to 4 years.
The second patient was seen 6 months
after surgery, and has not responded
to letters. The condition of one patient
is known by a letter from the referring
neurosurgeon. Three patients have had
post-operative CT scans done after 3
years, 2 ½ years and 1 year respectively.
Results
Clinical Features:
9 of the 11 patients belonged to the
second decade; 1 patient was 8 year
old and 1 female patient was 45 year
old. Eight were male patients and 3
were female patients. Headache, vomiting,
visual disturbances and stunted growth
were the common symptoms. Headache was
present in 9, vomiting in 5, visual
disturbances in 5, and 9 patients were
stunted physically. Visual disturbances
took the form of decreased visual acuity
in 5 patients. Three patients had defects
(bitemporal, right temporal, left superior
temporal). One of these patients had
a left superior temporal field loss
without any impairment of acuity.
Complete primary left optic atrophy
was present in 1 patient, optic disc
pallor was seen in 4 patients. Papilloedina
was seen in 4 patients. Only 2 patients
had a normal fundal appearance. The
45-year-old female patient had secondary
amenorrhoea; the 15-year-old female
patient never attained menarche, whereas
the 10-year-old female patient was too
young to do so.
Investigations: The skull X-rays showed
an enlarged pituitary fossa in 9 patients;
1 patient had only mild enlargement
of the sella, whereas the remaining
patient had a normal sized but demineralized
sella. Purely intra-sellar calcification
was seen in 3 patients, purely supra-sellar
in 1 patient and a combination of intra
-and supra- sellar calcification was
seen in 2 patients. Angiography was
carried out on only the first 2 patients,
in one of whom it showed an avascular
supra-sellar mass, and in the other
it was normal.
CT examination was carried out in all
the patients. It showed an intra - and
supra-sellar mass in 11 patients. The
supra-sellar extension occupied the
supra-sellar cistern in 8 patients and
in 3 it extended upto the third ventricle.
In 8 patients the lesion was predominantly
cystic with specks of calcification
within it. In 2 patients it was a combination
of solid and cystic components and in
1 it was totally calcified. In 2 patients
there was significant hydrocephalus
due to compression of the third ventricle.
Outcome: The last two patients who have
been operated less than a month ago
have had a sub-total excision and they
will be subjected to radiation treatment.
Their long-term outcome will be evident
only later. There has been no mortality
amongst these patients. The follow-up
period ranges from 5 days to 4 years.
Headache was ameliorated in 7 of the
8 patients in whom it was present. The
eighth patient with headache has been
operated only 5 days ago. Of the 5 patients
who had preoperative visual problems,
vision improved in 2, became worse in
2 and there was no change in 1 after
surgery. One of the 2 patient's vision
deteriorated immediately post-operatively
from a vision of 6/6 in the right eye
to finger counting at 5 feet. The second
patient had had a very poor tumour excision,
and his vision deteriorated over a period
of 1 year to near blindness. This was
obviously due to unrelieved optic nerve
compression. Of the 9 patients whose
growth was stunted, 7 patients continue
to remain stunted. The remaining 2 have
been operated only recently. Two patients
had already attained their secondary
sexual characters by the time their
lesions became symptomatic. Seven of
the other 9 patients have not attained
these characteristics yet. In the last
2 patients it is too early to judge
the effect of surgery in this respect.
Only 3 patients have had post-operative
CT scans at the end of 4 years, 2 ½
years and 1 year respectively. One has
no residue whereas the other two have
shown small intrasellar tumour residues.
Discussion
Craniopharyngiomas
can originate anywhere from the posterior
pharynx to the third ventricle[18].
The majority (50 to 85%) are supra-sellar
or para-sellar in location[14]. There
is the smaller group which originates
low around the pituitary stalk or even
below the diaphragma sellae[4],[13].
Depending on the type seen in large
numbers, various surgeons have pointed
out the merits of a particular surgical
approach[4],[9],[10],[15],[19],[21],[22],[24].
A general opinion has emerged that the
best results in the treatment of craniopharyngiomas
are achieved with a complete or at least
radical excision whenever possible.
Whenever a residue is left behind radiation
therapy is resorted to with good results[1],[2],[3],[12],[16],[20],[22],[23].
Unresectable cystic craniopharyngioma
has been managed by aspiration through
an Ommaya reservoir[5]. Baskin and Wilson[2]
reported 74 cases of craniopharyngioma.
They adopted various approaches like
the sub-frontal (in front of the chiasm
or through the lamina terminalis), an
approach between the carotid artery
and optic nerve, sub-temporal, trans-callosal,
suboccipital and the trans-spenoidal
route. The choice was obviously dictated
by the direction of the tumour growth.
Out of our 51 patients, 11 were selected
for treatment by the trans-sphenoidal
route. Two of these patients had normal
sized sellae. As mentioned earlier during
the trans-sphenoidal operation the tumour
in one patient was calcified and not
even a small bit could be excised, and
in the second patient the lesion was
very firm and it could only be biopsied.
In the remaining 9 patients a radical
tumour removal was accomplished. All
these patients had large cystic components
with small solid parts with calcified
areas. The sella was enlarged in all
these 9 patients. Due to a combination
of favourable circumstances a radical
excision could be achieved in all these
9 patients. In one of them the tumour
was excised totally, whereas in the
remainder a subtotal excision was possible.
Nine of the 11 patients have had radiation
therapy, whereas the last two who have
been operated only recently, are undergoing
this therapy. Admittedly the period
of follow-up is too short to talk about
cures, but in 7 of the 9 patients (excluding
the recently operated two patients)
a good excision has been obtained. In
two others the excision has been totally
unsatisfactory. This was due to the
very tough consistency of the masses
and only a little enlargement of the
sella. One of them has been lost to
follow up 6 months after surgery. In
one patient on whom a sub-total excision
was carried out, the vision inexplicably
deteriorated post-operatively. In the
remaining[7] patients there has been
no morbidity related to surgery and
there has been no mortality. Even the
two patients who were operated recently
did not show any immediate post-surgical
morbidity. The ability to achieve a
satisfactory tumour excision by the
trans-sphenoidal route in 9 of the 11
cases proves that the approach is useful
for a selected group of patients. This
is supported by similar earlier observations
by others[2],[4],[6],[7].[8],[13],[14],[18],[20].
Successful resection of craniopharyngioma
requires selecting the most efficacious
approach on the basis of pre-operative
neuroradiologic documentation of the
precise position and extension of tumour
with respect to the diaphragma sellae,
third ventricle, optic nerves, chiasm,
circle of Willis and parenchymal perforating
branches derived therefrom [17]. For
judicious use of any surgical approach
(including the trans-sphenoidal), a
pre-operative determination of the location
and spread of the craniopharyngioma
is absolutely necessary. This is best
determined by radiological means. Clinical
examination helps a little towards this.
On plain X-rays an enlarged sella points
to a possibly subdiaphragmatic location
of the tumour. This is easily corroborated
by a CT scan. A direct coronal scan
and sagittal reconstruction are a great
help. These views directly determine
the presence or absence of the lesion
within the sella. A tumour with even
a large midline superior extension is
amenable to removal by this route. It
being cystic (as many are) is a bonus!
Even a soft solid tumour lends itself
to a satisfactory removal. A firm or
calcified tumour can usually be removed
only partially. Increased vascularity
compounds the adverse situation. Finally
tumours with large parasellar, frontal
or posterior extensions are not suitable
for removal by the transsphenoidal route.
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