246 MICROSURGICAL PITUITARY
FRONTO-TEMPORAL
ADENOMAS
APPROACH
WITH EXTRASELLAR
TO
EXTENSION
H. A. M. van Alphen*
SUMMARY In the present paper the microsurgical, fronto-temporal technique for the surgical treatment of chromophobe pituitary adenomas with extra-sellar extension is described in detail. The complete treatment of expansive chromophobe adenomas includes 4000 rad of external irradiation by the rotation technique and hormonal replacement therapy. The results of this treatment in 36 consecutive patients from 1971 through 1975 are given. There is no mortality nor recurrence of tumor in the follow-up period. The postoperative morbidity is low, especially in the group operated by the microsurgical fronto-temporal approach. The visual acuity improved or normalized in 860/o, for the visual fields this percentage was 900/o. These results are compared to those of our own series of 65 patients, treated from 1945 through 1959, and to some other data from the literature. Finally, some arguments in favour of the intracranial approach versus the transsphenoidal approach are presented. INTRODUCTION pituitary tumors and especially chromophobe adenomas with suprasellar extension are characterized by hormonal dysfunction, chiasm syndrome and radiological alterations. The former two syndromes need treatment in the form of hormonal substitution and decompression of the optic chiasm by surgical tumor excision and/or by radiodestruction of the tumor. In chromophobe adenomas with disturbance of vision and/or visual field defects as a result of compression of the optic chiasm, radiotherapy as the only form of treatment seems to be insufficient. On the one hand, application of local irradiation (Bragg Peak proton irradiation, interstitial Curie-therapy) may cause an acute deterioration of vision and visual fields (KJELLBERG and KLIMAN, 1975). On the other hand, external irradiation in many cases results in inadequate shrinking of the tumor, in which cases an additional surgical decompression is necessary (HORRAX, 1955; own series). Therefore, adequate surgical decompression of the optic chiasm is the primary treatment of choice in expansive chromophobe adenomas, either by the transsphenoidal or by the intracranial approach. Both techniques, however, only provide a subtotal tumor excision and have to be followed by radiotherapy to diminish the chance of recurrence (HENDERSON, 1939; DEN HARTOG JAGER and VAN WIJNGAARDEN, 1961; VAN DER ZWAN, 1971; NICOLA, Most
1975). * Dept. of Neurosurgery, University Hospital, Wilhelmina Gasthuis, Amsterdam, The Netherlands. Clin. Neurol. Neurosurg. 1975-4
247 Whatever therapy is applied to chromophobe adenomas with suprasellar extension, in almost all cases it will bring about a definite loss in pituitary function, and this makes indefinite hormonal substitution necessary. The choice of treatment in these cases will therefore not be determined by the endocrinological state, but only by the question how to achieve the best and safest decompression of the optic chiasm. In our department, since 1960, all patients with chromophobe adenoma and chiasm disorders were SystematicalIy treated with intracapsular subtotal tumor excision by transfrontal approach and, since 1972, microsurgically by the frontotemporal route, 4000 rad of external irradiation by the rotation method, in a 4 weeks period, and hormonal replacement therapy with cortisone, thyranone and testosterone, if necessary. In this paper, first of all the microsurgical frontotemporal procedure will be described. Then the results in 36 consecutive patients from 1971 through 1975 wiI1 be given. Finally these results will be discussed and compared to our own series of patients from 1945 through 1959 (DEN HARTOG JAGER and VAN WIJNGAARDEN, 1961) and some other data from the literature. A justification for our treatment policy will be given.
SURGICALPROCEDURE
The patient is operated in supine position under general anesthesia with an orotracheal tube. The head is turned to the left at 60” and fixed in a Mayfield head holder. The right fronto-temporal approach is chosen by us in all cases of parasellar pathology, located medially from the left optic nerve and the left internal carotid artery, also in those cases in which there is a moderate extension to the left. The advantage of this procedure is, that in most cases the dominant hemisphere can be avoided. One gains a good experience in the surgical anatomy, by doing the procedure always in the same way. A fronto-temporal skin incision is made inside the hairline (fig. 1A). A small osteo~lasti~ ~raniotomy is performed and the pterion and the temporal bone are partly rongeured away, until the sphenoid ridge is completely free. A dura flap is made. During this procedure the patient is given 90 grams of urea intravenously, for dehydration of the brain. Now the Sylvian fissure can be seen (fig. 1B). A self retaining retractor is fixed at the skull edge and the frontal and temporal lobes are retracted for about 2-3 centimeters with two metal spatulas. Usualiy some basal veins from the tip of the temporal lobe to the cavernous sinus have to be sacrificed. Entering along the sphenoid ridge, the anterior clinoid process is found, and the right optic nerve. just behind, becomes visible through the arachnoid of the chiasm cisterns. At the base of the frontal lobe the olfactory nerve is visualised and can be followed to the lamina cribrosa. With this approach the olfactory nerve can be saved easily. Using the bipolar coagulator and the microscissors, the arachnoid of the chiasm cisterns and of the inner portion of the Sylvian fossa is opened. The cerebrospinal fluid flowing out is sucked away. As a result the lateral ventricles will collaps
248
Fig. 1 Consecutive steps of ihe fronto-temporal approach to pituitary tumors. A. 5kin incision. B. Entrance to the Sylvian fossa Jong the sphenoid ridge. C. Retracted frontal and temporal lobes. The optic nerve and the internal carotid artery are visuatised. 0. Complete visualisation of the parasellar area with pituitary tumor. Projection. as seen from the surgeon’s position.
a little and more space can be obtained. artery,
laterally
chromophobe mediately
from adenoma
beneath
the nerve, with
and between
The optic nerve
are dissected
suprasellar the nerve
free
expansion,
and the internal
(fig. 1C). In most the tumor
and the artery.
carotid cases
can be seen
The optic nerve
of im-
is dis-
placed by it in upward direction. After coagulating and cutting some arachnoidal adhesions between the optic nerve and the base of the frontal lobe, the latter can be retracted a little more. The separate branches of the internal carotid artery are dissected very meticulously by sectioning the arachnoid. After this, a magnificent view on the whole prechiasmal area is obtained (fig. 1D). The pituitary tumor is seen, bulging over the optic nerve and chiasm and over the anterior cerebral artery. Fig. 2 shows the complete surgical anatomy, as seen through the operative microscope at a lo-fold magnification. In many cases the site of compression of the optic nerves or the optic chiasm is seen clearly, if the anterior cerebral artery is dissected from the optic nerve, and carefully retracted backward. Then, a dark necrotic linear notch is seen in the nerve (fig. 2, arrow). At this site the optic nerve or chiasm is compressed between the tumor beneath and the anterior cerebral artery above. Sometimes the notch is asymmetric in both nerves or only present in one nerve or on one side of the chiasm (fig. 3). In these cases, there is a clear correlation between the patho-anatomical finding and the clin’cal visual defects. The tumor is punctured with a very thin needle, to exclude an aneurysm or, if the tumor is partly cystic, to gain some decompression. The tumor capsule is coagulated bipolarly at its prechiasmal part and between the optic nerve and the internal carotid artery, and incised at both sites with a small knife. Through these
Fig. 2 Surgical anatomy of the parasellar area with pituitary adenoma. Compression of optic nerve by the anterior cerebral artery (arrow).
the
Fig. 3 Optic chiasm, displaced in upward direction by pituitary adenoma. On the left, the black necrotic notch in the chiasm is visualised after retraction of the left anterior cerebral artery (XI‘row).
incisions the contents of the tumor can be sucked out with the aid of different curved small suckers, or, if the tumor tissue is tough, grasped with a mi~rorongeur and small curettes. After emptying of the tumor, the capsule will collaps and the optic chiasm will come down. The adhesions between the tumor capsule and both anterior cerebral arteries and both optic nerves can be separated. Part of the capsule can then be resected. During this procedure one has to be very cautious with respect to the surrounding structures. Touching the optic nerve may cause a permanent visual defect. Also disturbance of the small perforating arteries from the anterior cerebral artery can cause severe damage. In our opinion, it is impossible to perform a total and radical removal of a chromophobe adenoma, because the tumor capsule is not a real capsule, which can be dissected out (HARDY, 1969). It consists of basal dura and sellar diaphragm. Also in the bottom of the sella turcica, some tumor tissue will remain. Therefore, it is senseless to take risks by resecting the capsule ‘as much as possible’. Sometimes the capsule is fixed very tightly to one or both optic nerves (fig. 1D). Separation may disturb the very delicate arterial supply of the nerve. For that reason, it seems wise to leave this part of the capsule alone. After removal of the tumor, some hemorrhagic oozing from the inside of the remaining capsule may persist. To stop this, the tumor cavity is filled up by some small pieces of gel foam. After complete hemostasis, the spatulas are removed. The dura is closed meticulously to avoid postoperative leakage of cerebrospinal fluid. The boneflap is replaced and the wound is closed.
CLINICAL MATERIAL
Our series consists of 36 patients with chromophobe pituitary adenomas with marked suprasellar extension, treated from January 1971 through December 1975.
251 ‘TABLE I Age distribution
in 36 cases of chromopho~
adenomas.
Number of patients
10
There
20
were 25 males
30
40
50
and
11 females.
70
60
80 Age
The age distribution
is shown
in table
I.
The youngest patient was 16 years old, the oldest one 77 years of age. All patients had complete clinical, ophthalmologic, endocrinologic and neuroradiologic evaluation before treatment. All but one had more or less visual defects on one or both eyes. In most patients, the typical neuroradiologic signs of a chromophobe adenoma, as shown in fig. 4, were found. In at least 4 cases the diagnosis could not be ~on~rmed on the basis of endo~rinologi~ studies. 3 Patients, who had only minimal visual disorder, had had externa1 irradiation by the rotation technique as the first treatment.
Because
of further
deterioration
of vision
or visual
fields
a few months after radiotherapy, these had to be treated surgically. 33 Patients had surgery as the first treatment. In these patients radiation therapy was started about two weeks after surgery. The first 8 patients out of the total group were operated by the conventional transfronta1 approach. In all other cases m’crosurgical operations were carried out by the fronto-temporal route, as described above. All patients were given Dexamethasone and cortisone in the preoperative and postoperative periods. After that, maintenance doses of cortisone, thyranone, and testosterone were given, depending on the various blood levels. After discharge, all patients were seen in the out-patient departments of neurosurgery, ophthalmology, and endocrinology at regular intervals until recently. Therefore. the follow-up periods vary from 2 months to 5 years, with the average being 27 months.
Fig. 4 Typical neuroradiologic findings in pituitary adenoma. On the left: cnlargemeni ill the sella turcica and smooth impression of the antero-inferior part of the third ventricle (arrow); on the right: stretching of the internal carotid artery and upward displacement iii the anterior cerebral arteries (arrows).
RESULTS
There were no operative deaths. Nor was there any mortality in the follow-up period. The operative complications for the transfrontal approach as well as for the fronto-temporal approach are given in table II. One patient had a postoperative hemorrhage in the tumor cavity and had to be re-operated 24 hours after the first operation. He recovered completely except for permanent blindness of his left eye. One patient became blind on the left eye, probably a; a result of damage to the optic nerve during operation. In another patient, a temporary loss of vision occurred, which improved for the greater part in the course of some months. The operative results with regard to the visual acuity and the visual fields are shown in table III, which include the operative complications, mentioned above. The visual acuity and the visual fields were considered separately for each eye, and compared with the preoperative state of the same eye. In some cases, there was only a disturbance of visual acuity with normal visual fields, or the reverse. By normal visual acuity is meant a vision of 5/S, apart from the patients’ age or the presence of local ophthalmologic disorders. Three patients developed, after a marked improvement of visual functions immediately after the operation, a deterioration of visual acuity and visual field on one eye for the second time, 4-9 months after surgery. Some months later these stabilized again on a lower level. as compared to the immediate postoperative state. A satisfactory explanation for this phenomena could not be found. There were no signs of recurrence of tumor.
253 TABLE
II
Operative complications
in 36 patients with chromophobe
pituitary adenoma.
Transfrontal approach: (8 patients) 1 permanent blindness of the left eye, 1 temporary deterioration of vision on both eyes and E.E.G. focus, 1 permanent N III paresis, temporary diabetes insipidus, pulmonary embolism and 2 seizures, 1 permanent rhinorrhoea for 2 years, started 2 years after surgery and loss of smell. Fronto-temporal approach: (28 patients) 1 postoperative hemorrhage with permanent blindness of the left eye 1 temporary deterioration of vision on the right eye, 1 loss of smell
causes may be an irradiation effect or an arachnoiditis chiasmatis. series no recurrence of tumor occurred during the follow-up period. It is very difficult to quantify the patients’ recovery or validity. In the first
Possible
In the entire
place, most patients need a permanent hormonal replacement therapy in some form. Even if they are in a good hormonal balance, this may play an important psychological role. Impotence can be very disturbing for the patient, even though he is fully able to work. Also, blindness of one eye is not necessarily incompatible with normal life. Therefore, any estimation of validity will be arbitrary. In our series about 750/o of the patients are back to normal work or lead a normal life. In 25o/0 of the patients the ability to work is estimated at 5O-9OO/o. Finally, two patients have to be mentioned separately, because of other pathology apart from the pituitary adenoma. A 60 years old man was admitted because of a visual defect on the left eye since 6 months. 9 years before, he underwent a right-side nephrectomy for a hypernephroma,
TABLE
which appeared
to have been cured completely.
He had a marked
111
Operative results with regard to the visual functions in 36 patients with chromophobe Visual acuity: Normal and unchanged Normalized Improved Diminished and unchanged Deteriorated
26% 23% 37% 6% 8%
Visual fields: Normal and unchanged Normalized Improved Limited and unchanged Deteriorated
14% 34% 42% 4% 6%
adenomas.
Fig. 5 Pituitary adenoma (arrows on the left) and a saccular c~~nlmunicating artery (arrow on the right) in :i 60 years old man.
aneurysm
of the :tnicrit~
hypertension. Neuroradiologic examination revealed a pituitary ,tumor with considerable suprasellar extension. Endocrinologic investigation was non-contributing. The carotid angiography showed, beside the typical signs of a pituitary tumor, an aneurysm of the anterior communicating artery (fig. 5). At surgery, the aneurysm was clipped and the tumor, which appeared to be a chromophobe adenoma with an old hemorrhage in it, was removed in the usual way during the same procedure. The patient made an excellent recovery. A 65 year old woman had all signs of a chromophobe adenoma with suprasellar extension and compression of the optic chiasm. During the operation by the front+temporal approach a small sphenoid ridge meningioma was found by accident. Both tumors were removed in the same procedure. This patient also made a good recovery.
DISCUSSION
In 1961, 65 patients with chromophobe adenomas, treated in the neurological and neurosurgical departments of the University of Amsterdam between 1945 and 1959, were reviewed by DEN HARTOG JAGER and VAN WIJNGAARDEN. 38 patients were treated only surgically. 11 patients had irradiation only. 16 patients had combined surgical and radiation therapy. In 54 patients 62 operations were performed, all by the transfrontal approach. The operative mortality was 110/o. Improvement of visual functions was obtained by surgery only in 58o/0 of the patients, by irradation only in 450/o, and by the combined treatment in 62,50/o. The recurrence rate in the group of surgery only was 430/o, in the group of irradiation oniy: 37,50/o, and in the group of combined therapy: 0010.
255
These figures from our own department showed a great similarity with those from the older literature (HENDERSON (Cushing’s series), 1939; HoaRAx, 1958). VAN DER ZWAN (1971), who reviewed 80 patients treated surgically (trans-front~~l approach) at the neurosurgical departments of the Universities of Leden and Rotterdam between 1954 and 1969, mentioned an operative mortality of 5O/n. In the surviving patients (66 after 6 months), an improvement of visual function was seen in 66,60/o by surgery only and in 750/o by the combined therapy. The recurrence rate in both groups was 360/o and 6()/o respectively. In all series the criteria for the intracranial approach were almost the same. Comparing the present series with other data from the literature, and especially with our own series between 1945 and 1959, a remarkable progress has been made during the last 5 years. Many factors are responsible for this: better anesthesia, prevention of brain edema, better endocrinologic investigation and control, etc. As shown in table II, the microsurgical, fronto-temporal technique seems to be a further improvement, especially with respect to the operative complications and the postoperative morbidity. With regard to tumor recurrence no conclusions can be drawn from this series, because the follow-up period was rather short. However, from earlier studies (HORRAX,SMEDAL, TRUMP, GRANKE and WRIGHT, 1955; DEN HARTOGJAGER and VAN WIJNGAARDEN,1961; VAN DER
ZWAN, 1971) it is sufficiently known, that surgery combined with irradiation is the most favourable treatment. Of current surgical procedures, transsphenoidal and intracranial hypophysectomy, the former has come in the front more and more in recent years, also for the treatment of those pituitary adenomas with supraselfar expansion (HARDY, 1975; NICOLA,1975). At the 1975 meeting of the American Association of Neurological Surgeons, one of the conclusions of Kjellberg’s paper on ‘Experience with neurological treatment of 500 pituitary tumors’ was, that ‘frontal craniotomy need
rarely be performed ogical Surgery’,
except for certain advanced cases’. In ‘Progress in NeurolVol. 6 (KRAYENB~~HL, MASPESand SWEET, eds., 1975) on pituitary
pathology, 5 chapters are devoted to the various transsphenoidal techniques, 2 to some radiation methods and none to the intracranial approach. SWEET’Sargument for this, in the preface of the book, is, that the younger man ‘is unlikely ever to get enough patients to enable him to learn how to achieve the excellent results of the few transfrontal maestros in the world’. The most important arguments for this are (NICOLA, 1975): the benignity
of the transsphenoidal route, the low mortality, the better visual results, the lower risks in elderly people and in bad risk cases, and less trauma to the optic nerves and chiasm. As shown in our present series, however, these arguments do not necessarily plead against the intracrai~ial approach. On the other hand, there are reasons to favour the microsurgical frontotemporal approach, as the treatment of choice. 1 Even with a complete neuroradiologic evaluation, the intracranial extension of
the tumor can not always be predicted.
Moreover,
the extent of the visual
256 disorder is not always a reliable measure of the suprasellar expansion. In somt” cases the tumor grows between the optic nerve and the internal carotid arter! and around the small branches of the anterior and middle cerebral arterie\ (fig. 1D). Here, a safe decompression of the various structures can only be performed, if one has a good visualisation of these structures. 2 Sometimes, as mentioned, the pituitary adenoma may not be the only pathologic entity. Some other lesions can be diagnosed before surgery (fig. 5), others may only be found accidently. In both cases the additional lesions can be cured during the same procedure by the intracranial approach. 3 ‘The diagnosis will always remain in doubt as long as a pathologic study is not obtained’. (HARDY, 1969). On the one hand, the various endocrinologic and neuroradiologic findings are not always typical. The normal sella turcica, the absence of endocrinologic disorders, and the deposit of calcarous salt in the tumor in cases of chromophobe adenomas are well known. (See also NICOLA, 1975). On the other hand, a number of other sellar or suprasellar lesions may simulate the picture of an expanding chromophobe adenoma in its various aspects. Sometimes, such lesions can be identified by proper diagnostic studies, such as an intrasellar aneurysm, or an empty sella. In other cases, however, the diagnosis will remain questionable until surgery. This is especially true in cases of suprasellar tumors such as: craniopharyngeomas, suprasellar chordomas and chondromas, hamartomas, optic gliomas and pituitary metastasis. Therefore, as long as there is any doubt about the extension or the nature of the tumor, we feel, that the direct exposure is the safest way. In order to save vision, we need good vision.
REFERENCES
HARDY, J. (1969) Transphenoidal microsurgery of the normal and pathologica pituitary. Clin. Neurosurg. 16: 185. HARDY, J. (1975) Trans-sphenoidal microsurgical removal of pituitary micro-adenoma. In: Progr. neurol. Surg., vol. 6: 200. (Karger, Basel). DEN HARTOG JAGER, w. A. and VAN WIJNQAARDEN, G. K. (1961) Ervaringen bij de behandeling van het chromofobe adenoom van de hypofyse. Ned. T. Geneesk. 105: 2496. HENDERSON, w. R. (1939) The pituitary adenomata. A follow-up study of the surgical results in 338 cases (dr. Harvey Cushing’s series). Brit. 3. Surg. 26: 811. HORRAX, G., SMEDAL, 36. I.,TRUMP, 3. G., GRANKE, R. c. and WRIGHT, K. A. (1955) Present-day treatment of pituitary adenomas. Surgery versus X-ray therapy. New. Eagl. J. Med. 252: 524. HORRAX, G. (19.58) Treatment of pituitary adenomas. Surgery versus radiation. Arch. Neutol. Psychiat. 79: 1. KJELLBERG, R. N. and KLIMAN, B. (1975) Bragg peak proton hypophysectomy for byperpituitarism, induced hypopituitarism and neoplasms. In: Progr. neurol. Surg., vol. 6: 295-32.5 (Karger, Basel). KRAYENBijHL, H., MASPES, P. E. and SWEET, w. H. (Editors): Progress in neurological surgery, vol. 6 (Karger, Basel). NIcOLA, G. (1975) Trans-sphenoidal surgery for pituitary adenomas with extrasellar extension. In: Progr. neural. Surg., vol. 6: 142-199 (Karger, Basel). VAN DER iWAN, A. (19%) Pituitary Tumors. Thesis, L&den (De Kempenaer, Gegstgeest).
FRONTO-TEMPORAL
ADENOMAS
APPROACH
WITH EXTRASELLAR
TO
EXTENSION
H. A. M. van Alphen*
SUMMARY In the present paper the microsurgical, fronto-temporal technique for the surgical treatment of chromophobe pituitary adenomas with extra-sellar extension is described in detail. The complete treatment of expansive chromophobe adenomas includes 4000 rad of external irradiation by the rotation technique and hormonal replacement therapy. The results of this treatment in 36 consecutive patients from 1971 through 1975 are given. There is no mortality nor recurrence of tumor in the follow-up period. The postoperative morbidity is low, especially in the group operated by the microsurgical fronto-temporal approach. The visual acuity improved or normalized in 860/o, for the visual fields this percentage was 900/o. These results are compared to those of our own series of 65 patients, treated from 1945 through 1959, and to some other data from the literature. Finally, some arguments in favour of the intracranial approach versus the transsphenoidal approach are presented. INTRODUCTION pituitary tumors and especially chromophobe adenomas with suprasellar extension are characterized by hormonal dysfunction, chiasm syndrome and radiological alterations. The former two syndromes need treatment in the form of hormonal substitution and decompression of the optic chiasm by surgical tumor excision and/or by radiodestruction of the tumor. In chromophobe adenomas with disturbance of vision and/or visual field defects as a result of compression of the optic chiasm, radiotherapy as the only form of treatment seems to be insufficient. On the one hand, application of local irradiation (Bragg Peak proton irradiation, interstitial Curie-therapy) may cause an acute deterioration of vision and visual fields (KJELLBERG and KLIMAN, 1975). On the other hand, external irradiation in many cases results in inadequate shrinking of the tumor, in which cases an additional surgical decompression is necessary (HORRAX, 1955; own series). Therefore, adequate surgical decompression of the optic chiasm is the primary treatment of choice in expansive chromophobe adenomas, either by the transsphenoidal or by the intracranial approach. Both techniques, however, only provide a subtotal tumor excision and have to be followed by radiotherapy to diminish the chance of recurrence (HENDERSON, 1939; DEN HARTOG JAGER and VAN WIJNGAARDEN, 1961; VAN DER ZWAN, 1971; NICOLA, Most
1975). * Dept. of Neurosurgery, University Hospital, Wilhelmina Gasthuis, Amsterdam, The Netherlands. Clin. Neurol. Neurosurg. 1975-4
247 Whatever therapy is applied to chromophobe adenomas with suprasellar extension, in almost all cases it will bring about a definite loss in pituitary function, and this makes indefinite hormonal substitution necessary. The choice of treatment in these cases will therefore not be determined by the endocrinological state, but only by the question how to achieve the best and safest decompression of the optic chiasm. In our department, since 1960, all patients with chromophobe adenoma and chiasm disorders were SystematicalIy treated with intracapsular subtotal tumor excision by transfrontal approach and, since 1972, microsurgically by the frontotemporal route, 4000 rad of external irradiation by the rotation method, in a 4 weeks period, and hormonal replacement therapy with cortisone, thyranone and testosterone, if necessary. In this paper, first of all the microsurgical frontotemporal procedure will be described. Then the results in 36 consecutive patients from 1971 through 1975 wiI1 be given. Finally these results will be discussed and compared to our own series of patients from 1945 through 1959 (DEN HARTOG JAGER and VAN WIJNGAARDEN, 1961) and some other data from the literature. A justification for our treatment policy will be given.
SURGICALPROCEDURE
The patient is operated in supine position under general anesthesia with an orotracheal tube. The head is turned to the left at 60” and fixed in a Mayfield head holder. The right fronto-temporal approach is chosen by us in all cases of parasellar pathology, located medially from the left optic nerve and the left internal carotid artery, also in those cases in which there is a moderate extension to the left. The advantage of this procedure is, that in most cases the dominant hemisphere can be avoided. One gains a good experience in the surgical anatomy, by doing the procedure always in the same way. A fronto-temporal skin incision is made inside the hairline (fig. 1A). A small osteo~lasti~ ~raniotomy is performed and the pterion and the temporal bone are partly rongeured away, until the sphenoid ridge is completely free. A dura flap is made. During this procedure the patient is given 90 grams of urea intravenously, for dehydration of the brain. Now the Sylvian fissure can be seen (fig. 1B). A self retaining retractor is fixed at the skull edge and the frontal and temporal lobes are retracted for about 2-3 centimeters with two metal spatulas. Usualiy some basal veins from the tip of the temporal lobe to the cavernous sinus have to be sacrificed. Entering along the sphenoid ridge, the anterior clinoid process is found, and the right optic nerve. just behind, becomes visible through the arachnoid of the chiasm cisterns. At the base of the frontal lobe the olfactory nerve is visualised and can be followed to the lamina cribrosa. With this approach the olfactory nerve can be saved easily. Using the bipolar coagulator and the microscissors, the arachnoid of the chiasm cisterns and of the inner portion of the Sylvian fossa is opened. The cerebrospinal fluid flowing out is sucked away. As a result the lateral ventricles will collaps
248
Fig. 1 Consecutive steps of ihe fronto-temporal approach to pituitary tumors. A. 5kin incision. B. Entrance to the Sylvian fossa Jong the sphenoid ridge. C. Retracted frontal and temporal lobes. The optic nerve and the internal carotid artery are visuatised. 0. Complete visualisation of the parasellar area with pituitary tumor. Projection. as seen from the surgeon’s position.
a little and more space can be obtained. artery,
laterally
chromophobe mediately
from adenoma
beneath
the nerve, with
and between
The optic nerve
are dissected
suprasellar the nerve
free
expansion,
and the internal
(fig. 1C). In most the tumor
and the artery.
carotid cases
can be seen
The optic nerve
of im-
is dis-
placed by it in upward direction. After coagulating and cutting some arachnoidal adhesions between the optic nerve and the base of the frontal lobe, the latter can be retracted a little more. The separate branches of the internal carotid artery are dissected very meticulously by sectioning the arachnoid. After this, a magnificent view on the whole prechiasmal area is obtained (fig. 1D). The pituitary tumor is seen, bulging over the optic nerve and chiasm and over the anterior cerebral artery. Fig. 2 shows the complete surgical anatomy, as seen through the operative microscope at a lo-fold magnification. In many cases the site of compression of the optic nerves or the optic chiasm is seen clearly, if the anterior cerebral artery is dissected from the optic nerve, and carefully retracted backward. Then, a dark necrotic linear notch is seen in the nerve (fig. 2, arrow). At this site the optic nerve or chiasm is compressed between the tumor beneath and the anterior cerebral artery above. Sometimes the notch is asymmetric in both nerves or only present in one nerve or on one side of the chiasm (fig. 3). In these cases, there is a clear correlation between the patho-anatomical finding and the clin’cal visual defects. The tumor is punctured with a very thin needle, to exclude an aneurysm or, if the tumor is partly cystic, to gain some decompression. The tumor capsule is coagulated bipolarly at its prechiasmal part and between the optic nerve and the internal carotid artery, and incised at both sites with a small knife. Through these
Fig. 2 Surgical anatomy of the parasellar area with pituitary adenoma. Compression of optic nerve by the anterior cerebral artery (arrow).
the
Fig. 3 Optic chiasm, displaced in upward direction by pituitary adenoma. On the left, the black necrotic notch in the chiasm is visualised after retraction of the left anterior cerebral artery (XI‘row).
incisions the contents of the tumor can be sucked out with the aid of different curved small suckers, or, if the tumor tissue is tough, grasped with a mi~rorongeur and small curettes. After emptying of the tumor, the capsule will collaps and the optic chiasm will come down. The adhesions between the tumor capsule and both anterior cerebral arteries and both optic nerves can be separated. Part of the capsule can then be resected. During this procedure one has to be very cautious with respect to the surrounding structures. Touching the optic nerve may cause a permanent visual defect. Also disturbance of the small perforating arteries from the anterior cerebral artery can cause severe damage. In our opinion, it is impossible to perform a total and radical removal of a chromophobe adenoma, because the tumor capsule is not a real capsule, which can be dissected out (HARDY, 1969). It consists of basal dura and sellar diaphragm. Also in the bottom of the sella turcica, some tumor tissue will remain. Therefore, it is senseless to take risks by resecting the capsule ‘as much as possible’. Sometimes the capsule is fixed very tightly to one or both optic nerves (fig. 1D). Separation may disturb the very delicate arterial supply of the nerve. For that reason, it seems wise to leave this part of the capsule alone. After removal of the tumor, some hemorrhagic oozing from the inside of the remaining capsule may persist. To stop this, the tumor cavity is filled up by some small pieces of gel foam. After complete hemostasis, the spatulas are removed. The dura is closed meticulously to avoid postoperative leakage of cerebrospinal fluid. The boneflap is replaced and the wound is closed.
CLINICAL MATERIAL
Our series consists of 36 patients with chromophobe pituitary adenomas with marked suprasellar extension, treated from January 1971 through December 1975.
251 ‘TABLE I Age distribution
in 36 cases of chromopho~
adenomas.
Number of patients
10
There
20
were 25 males
30
40
50
and
11 females.
70
60
80 Age
The age distribution
is shown
in table
I.
The youngest patient was 16 years old, the oldest one 77 years of age. All patients had complete clinical, ophthalmologic, endocrinologic and neuroradiologic evaluation before treatment. All but one had more or less visual defects on one or both eyes. In most patients, the typical neuroradiologic signs of a chromophobe adenoma, as shown in fig. 4, were found. In at least 4 cases the diagnosis could not be ~on~rmed on the basis of endo~rinologi~ studies. 3 Patients, who had only minimal visual disorder, had had externa1 irradiation by the rotation technique as the first treatment.
Because
of further
deterioration
of vision
or visual
fields
a few months after radiotherapy, these had to be treated surgically. 33 Patients had surgery as the first treatment. In these patients radiation therapy was started about two weeks after surgery. The first 8 patients out of the total group were operated by the conventional transfronta1 approach. In all other cases m’crosurgical operations were carried out by the fronto-temporal route, as described above. All patients were given Dexamethasone and cortisone in the preoperative and postoperative periods. After that, maintenance doses of cortisone, thyranone, and testosterone were given, depending on the various blood levels. After discharge, all patients were seen in the out-patient departments of neurosurgery, ophthalmology, and endocrinology at regular intervals until recently. Therefore. the follow-up periods vary from 2 months to 5 years, with the average being 27 months.
Fig. 4 Typical neuroradiologic findings in pituitary adenoma. On the left: cnlargemeni ill the sella turcica and smooth impression of the antero-inferior part of the third ventricle (arrow); on the right: stretching of the internal carotid artery and upward displacement iii the anterior cerebral arteries (arrows).
RESULTS
There were no operative deaths. Nor was there any mortality in the follow-up period. The operative complications for the transfrontal approach as well as for the fronto-temporal approach are given in table II. One patient had a postoperative hemorrhage in the tumor cavity and had to be re-operated 24 hours after the first operation. He recovered completely except for permanent blindness of his left eye. One patient became blind on the left eye, probably a; a result of damage to the optic nerve during operation. In another patient, a temporary loss of vision occurred, which improved for the greater part in the course of some months. The operative results with regard to the visual acuity and the visual fields are shown in table III, which include the operative complications, mentioned above. The visual acuity and the visual fields were considered separately for each eye, and compared with the preoperative state of the same eye. In some cases, there was only a disturbance of visual acuity with normal visual fields, or the reverse. By normal visual acuity is meant a vision of 5/S, apart from the patients’ age or the presence of local ophthalmologic disorders. Three patients developed, after a marked improvement of visual functions immediately after the operation, a deterioration of visual acuity and visual field on one eye for the second time, 4-9 months after surgery. Some months later these stabilized again on a lower level. as compared to the immediate postoperative state. A satisfactory explanation for this phenomena could not be found. There were no signs of recurrence of tumor.
253 TABLE
II
Operative complications
in 36 patients with chromophobe
pituitary adenoma.
Transfrontal approach: (8 patients) 1 permanent blindness of the left eye, 1 temporary deterioration of vision on both eyes and E.E.G. focus, 1 permanent N III paresis, temporary diabetes insipidus, pulmonary embolism and 2 seizures, 1 permanent rhinorrhoea for 2 years, started 2 years after surgery and loss of smell. Fronto-temporal approach: (28 patients) 1 postoperative hemorrhage with permanent blindness of the left eye 1 temporary deterioration of vision on the right eye, 1 loss of smell
causes may be an irradiation effect or an arachnoiditis chiasmatis. series no recurrence of tumor occurred during the follow-up period. It is very difficult to quantify the patients’ recovery or validity. In the first
Possible
In the entire
place, most patients need a permanent hormonal replacement therapy in some form. Even if they are in a good hormonal balance, this may play an important psychological role. Impotence can be very disturbing for the patient, even though he is fully able to work. Also, blindness of one eye is not necessarily incompatible with normal life. Therefore, any estimation of validity will be arbitrary. In our series about 750/o of the patients are back to normal work or lead a normal life. In 25o/0 of the patients the ability to work is estimated at 5O-9OO/o. Finally, two patients have to be mentioned separately, because of other pathology apart from the pituitary adenoma. A 60 years old man was admitted because of a visual defect on the left eye since 6 months. 9 years before, he underwent a right-side nephrectomy for a hypernephroma,
TABLE
which appeared
to have been cured completely.
He had a marked
111
Operative results with regard to the visual functions in 36 patients with chromophobe Visual acuity: Normal and unchanged Normalized Improved Diminished and unchanged Deteriorated
26% 23% 37% 6% 8%
Visual fields: Normal and unchanged Normalized Improved Limited and unchanged Deteriorated
14% 34% 42% 4% 6%
adenomas.
Fig. 5 Pituitary adenoma (arrows on the left) and a saccular c~~nlmunicating artery (arrow on the right) in :i 60 years old man.
aneurysm
of the :tnicrit~
hypertension. Neuroradiologic examination revealed a pituitary ,tumor with considerable suprasellar extension. Endocrinologic investigation was non-contributing. The carotid angiography showed, beside the typical signs of a pituitary tumor, an aneurysm of the anterior communicating artery (fig. 5). At surgery, the aneurysm was clipped and the tumor, which appeared to be a chromophobe adenoma with an old hemorrhage in it, was removed in the usual way during the same procedure. The patient made an excellent recovery. A 65 year old woman had all signs of a chromophobe adenoma with suprasellar extension and compression of the optic chiasm. During the operation by the front+temporal approach a small sphenoid ridge meningioma was found by accident. Both tumors were removed in the same procedure. This patient also made a good recovery.
DISCUSSION
In 1961, 65 patients with chromophobe adenomas, treated in the neurological and neurosurgical departments of the University of Amsterdam between 1945 and 1959, were reviewed by DEN HARTOG JAGER and VAN WIJNGAARDEN. 38 patients were treated only surgically. 11 patients had irradiation only. 16 patients had combined surgical and radiation therapy. In 54 patients 62 operations were performed, all by the transfrontal approach. The operative mortality was 110/o. Improvement of visual functions was obtained by surgery only in 58o/0 of the patients, by irradation only in 450/o, and by the combined treatment in 62,50/o. The recurrence rate in the group of surgery only was 430/o, in the group of irradiation oniy: 37,50/o, and in the group of combined therapy: 0010.
255
These figures from our own department showed a great similarity with those from the older literature (HENDERSON (Cushing’s series), 1939; HoaRAx, 1958). VAN DER ZWAN (1971), who reviewed 80 patients treated surgically (trans-front~~l approach) at the neurosurgical departments of the Universities of Leden and Rotterdam between 1954 and 1969, mentioned an operative mortality of 5O/n. In the surviving patients (66 after 6 months), an improvement of visual function was seen in 66,60/o by surgery only and in 750/o by the combined therapy. The recurrence rate in both groups was 360/o and 6()/o respectively. In all series the criteria for the intracranial approach were almost the same. Comparing the present series with other data from the literature, and especially with our own series between 1945 and 1959, a remarkable progress has been made during the last 5 years. Many factors are responsible for this: better anesthesia, prevention of brain edema, better endocrinologic investigation and control, etc. As shown in table II, the microsurgical, fronto-temporal technique seems to be a further improvement, especially with respect to the operative complications and the postoperative morbidity. With regard to tumor recurrence no conclusions can be drawn from this series, because the follow-up period was rather short. However, from earlier studies (HORRAX,SMEDAL, TRUMP, GRANKE and WRIGHT, 1955; DEN HARTOGJAGER and VAN WIJNGAARDEN,1961; VAN DER
ZWAN, 1971) it is sufficiently known, that surgery combined with irradiation is the most favourable treatment. Of current surgical procedures, transsphenoidal and intracranial hypophysectomy, the former has come in the front more and more in recent years, also for the treatment of those pituitary adenomas with supraselfar expansion (HARDY, 1975; NICOLA,1975). At the 1975 meeting of the American Association of Neurological Surgeons, one of the conclusions of Kjellberg’s paper on ‘Experience with neurological treatment of 500 pituitary tumors’ was, that ‘frontal craniotomy need
rarely be performed ogical Surgery’,
except for certain advanced cases’. In ‘Progress in NeurolVol. 6 (KRAYENB~~HL, MASPESand SWEET, eds., 1975) on pituitary
pathology, 5 chapters are devoted to the various transsphenoidal techniques, 2 to some radiation methods and none to the intracranial approach. SWEET’Sargument for this, in the preface of the book, is, that the younger man ‘is unlikely ever to get enough patients to enable him to learn how to achieve the excellent results of the few transfrontal maestros in the world’. The most important arguments for this are (NICOLA, 1975): the benignity
of the transsphenoidal route, the low mortality, the better visual results, the lower risks in elderly people and in bad risk cases, and less trauma to the optic nerves and chiasm. As shown in our present series, however, these arguments do not necessarily plead against the intracrai~ial approach. On the other hand, there are reasons to favour the microsurgical frontotemporal approach, as the treatment of choice. 1 Even with a complete neuroradiologic evaluation, the intracranial extension of
the tumor can not always be predicted.
Moreover,
the extent of the visual
256 disorder is not always a reliable measure of the suprasellar expansion. In somt” cases the tumor grows between the optic nerve and the internal carotid arter! and around the small branches of the anterior and middle cerebral arterie\ (fig. 1D). Here, a safe decompression of the various structures can only be performed, if one has a good visualisation of these structures. 2 Sometimes, as mentioned, the pituitary adenoma may not be the only pathologic entity. Some other lesions can be diagnosed before surgery (fig. 5), others may only be found accidently. In both cases the additional lesions can be cured during the same procedure by the intracranial approach. 3 ‘The diagnosis will always remain in doubt as long as a pathologic study is not obtained’. (HARDY, 1969). On the one hand, the various endocrinologic and neuroradiologic findings are not always typical. The normal sella turcica, the absence of endocrinologic disorders, and the deposit of calcarous salt in the tumor in cases of chromophobe adenomas are well known. (See also NICOLA, 1975). On the other hand, a number of other sellar or suprasellar lesions may simulate the picture of an expanding chromophobe adenoma in its various aspects. Sometimes, such lesions can be identified by proper diagnostic studies, such as an intrasellar aneurysm, or an empty sella. In other cases, however, the diagnosis will remain questionable until surgery. This is especially true in cases of suprasellar tumors such as: craniopharyngeomas, suprasellar chordomas and chondromas, hamartomas, optic gliomas and pituitary metastasis. Therefore, as long as there is any doubt about the extension or the nature of the tumor, we feel, that the direct exposure is the safest way. In order to save vision, we need good vision.
REFERENCES
HARDY, J. (1969) Transphenoidal microsurgery of the normal and pathologica pituitary. Clin. Neurosurg. 16: 185. HARDY, J. (1975) Trans-sphenoidal microsurgical removal of pituitary micro-adenoma. In: Progr. neurol. Surg., vol. 6: 200. (Karger, Basel). DEN HARTOG JAGER, w. A. and VAN WIJNQAARDEN, G. K. (1961) Ervaringen bij de behandeling van het chromofobe adenoom van de hypofyse. Ned. T. Geneesk. 105: 2496. HENDERSON, w. R. (1939) The pituitary adenomata. A follow-up study of the surgical results in 338 cases (dr. Harvey Cushing’s series). Brit. 3. Surg. 26: 811. HORRAX, G., SMEDAL, 36. I.,TRUMP, 3. G., GRANKE, R. c. and WRIGHT, K. A. (1955) Present-day treatment of pituitary adenomas. Surgery versus X-ray therapy. New. Eagl. J. Med. 252: 524. HORRAX, G. (19.58) Treatment of pituitary adenomas. Surgery versus radiation. Arch. Neutol. Psychiat. 79: 1. KJELLBERG, R. N. and KLIMAN, B. (1975) Bragg peak proton hypophysectomy for byperpituitarism, induced hypopituitarism and neoplasms. In: Progr. neurol. Surg., vol. 6: 295-32.5 (Karger, Basel). KRAYENBijHL, H., MASPES, P. E. and SWEET, w. H. (Editors): Progress in neurological surgery, vol. 6 (Karger, Basel). NIcOLA, G. (1975) Trans-sphenoidal surgery for pituitary adenomas with extrasellar extension. In: Progr. neural. Surg., vol. 6: 142-199 (Karger, Basel). VAN DER iWAN, A. (19%) Pituitary Tumors. Thesis, L&den (De Kempenaer, Gegstgeest).
