Book - The Pineal Organ (1940) 31
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Gladstone RJ. and Wakeley C. The Pineal Organ. (1940) Bailliere, Tindall & Cox, London. PDF
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The Pineal Organ
Chapter 31 Operative Technique
Although it is possible to operate on the pineal using local infiltration of the scalp and some scopolamine and morphine, yet it is preferable, in the author's opinion, to use rectal avertin, local infiltration of the scalp with J per cent, novocain, and to follow with intratracheal gas and oxygen. The reasons for using intratracheal gas and oxygen are that it is desirable to have the patient completely quiet while the deep approach to the pineal is proceeded with, and that if the patient stops breathing, oxygen or
Fig. 289. — Drawing showing the Skin Incision and Site for the Burr Holes in the Bone so as to Expose the Posterior two-thirds of the Cerebral Hemisphere.
carbondioxide can be given, a very desirable precaution when operating near the brain-stem, where slight deflections in either direction may press or drag upon the respiratory centre.
There are only two approaches to the pineal gland which are of any practical value, and both demand a large right occipito-parietal osteoplastic flap.
1. Dandy's Operation. — This is the method of choice, and is based on experimental operative procedure performed on dogs. After preliminary infiltration of the scalp with novocain, a large occipito-parietal scalp flap is fashioned (Fig. 289) and bleeding controlled. Some five
441
442
THE PINEAL ORGAN
burr holes are made in the skull at the periphery of the scalp incision and these burr holes are joined by means of a Gigli saw, which is inserted by a special curved introducer (Fig. 290). After the saw has been introduced, the bone between the burr holes is cut on the bevel, the introducers acting as a protector to the underlying dura mater and brain (Fig. 291). When all the burr holes have been united with the exception of the lowest two, the osteoplastic flap can be elevated and fractured across its narrow and thinned-out base ; it is then hinged outwards on the temporal muscle. Bleeding vessels in the dura mater are underrun
Fig. 290. — Useful Gigli Saw Guide.
Fig. 291. — The Method of Introducing a Gigli Saw between Two Burr Holes.
with silk sutures, while those occurring in the bone are controlled with Horsley's bone wax. If there is a considerable increase of the intracranial pressure this can be diminished by the administration of 20 c.c. of hypertonic saline (15 per cent.) at the commencement of the operation, but as a rule this is not necessary because adequate reduction of the intracranial pressure may be produced by tapping the lateral ventricle. It is a remarkable fact that although an internal hydrocephalus causes gradual destruction of cerebral tissue, yet this hydrocephalus is advantageous to the surgeon when removing a pineal tumour ; otherwise it would be impossible to retract the posterior part of a normal hemisphere without causing some permanent damage. When the fluid from the ventricle is withdrawn in a case of internal hydrocephalus, the flattened-out hemisphere can be retracted without further damage ensuing.
A flap of dura mater is turned outwards on top of the osteoplastic
OPERATIVE TECHNIQUE 443
flap (Fig. 292) and bleeding from the cut surface of the dura is controlled with silver clips. As the mesial margin of the flap extends almost to the superior sagittal sinus, there are numerous bleeding vessels which will require ligature ; some of the smaller ones may be dealt with by silver clips. The lateral ventricle is then tapped at the junction of its body and descending horn, the cerebrospinal fluid being allowed to flow away over the brain ; the needle is left in situ for as long as possible to ensure complete evacuation of the ventricle.
The next step is to divide any cerebral veins which may be running
Fig. 292. — The Method in which the Osteoplastic Flap is raised and turned outwards : Flap of Dura Mater is then turned outwards and the Lateral Ventricle tapped.
from the upper part of the hemisphere into the superior sagittal sinus. There are five or six of these veins, and they can be secured between fine ligatures or silver clips. Care should be taken to avoid injury to the vein which drains the Rolandic area of the brain, otherwise a transient hemiplegia may result.
After the cerebral veins have been divided the whole of the posterior extremity of the hemisphere is to be retracted to such an extent as to expose the falx cerebri (Fig. 293). Continued retraction will bring the inferior longitudinal sinus into view, and beneath it the corpus callosum (Fig. 294). To obtain an adequate exposure of the splenium of the corpus callosum, it is often advisable to divide the inferior longitudinal
444
THE PINEAL ORGAN
sinus between silver clips, and then slit up the lower border of the falx for half an inch or more with a curved tenotomy knife (Fig. 295). The splenium of the corpus callosum is then incised in the midline and the tumour exposed. Any bleeding that may be encountered in this procedure is checked by the diathermy point. The most important structure in relation to the tumour is the great vein of Galen, which lies under the fornix. This vein and its tributaries should be carefully preserved.
Fig. 293. — The Exposure of the Corpus Callosum. The Ligated Cerebral Veins can be seen as they enter the Superior Sagittal Sinus.
The tumour is carefully prised out of its bed by means of a curved dissector, such as Adson's. It may be that the third ventricle is opened while the tumour is dissected out of its bed, but this does not matter (Figs. 294, 296). Absolute hsemostasis is essential, and all bleeding points are controlled by the application of silver clips or the use of the diathermy point.
The tumour bed must be quite dry before completing the operation. The posterior part of the cerebral hemisphere is allowed to fall back into place, and the dura mater united with one or two tethering sutures. Drainage by means of a fine corrugated rubber dam is often necessary
OPERATIVE TECHNIQUE
445
Fig. 294. — The Posterior Part of the Cerebral Hemisphere is retracted so as to expose the corpus callosum.
Fig. 295. — The Inferior Surface of the Falx has been divided, together with the Inferior Sagittal Sinus. The Posterior End of the Corpus Callosum has been divided, exposing the Pineal Tumour.
for a day or so. The osteoplastic flap is replaced and the scalp approximated by two layers of sutures. The head is covered with a firm bandage, and the patient nursed flat for the first three days and then allowed a
44-6 THE PINEAL ORGAN
pillow. With the depletion of cerebrospinal fluid during the operation, it is necessary to balance this by an adequate intake, and therefore after the operation a continuous rectal saline infusion is instituted. A purge is given on the second day after operation, and if there is much headache a lumbar operation is performed. The stitches are removed on the tenth day, and the patient is subsequently allowed to get out of bed.
2. Van Wagenen's Operation.— The second method of surgical approach is that devised by van Wagenen, in which the tumour is attacked
Fig. 296. — Section through the Brain showing the Exposure and Incision of the Corpus Callo SUM.
Fig. 297.
-The Actual Removal of a Pineal
Tumour.
through the median wall of the lateral ventricle. It is an easier method and the route is less vascular, and the tributaries of the great vein of Galen can be more easily seen and dealt with. The disadvantage, however, is that it leaves some permanent disturbance of function in the form of hemiplegia and homonymous hemianopia.
The first part of the operation is very similar to Dandy's approach — an osteoplastic flap is fashioned and turned outwards (Fig. 298). The dura mater is incised and a flap turned downwards. A reversed L-shaped incision about 6 cm. in length is made in the cortex, extending from the posterior end of the superior temporal lobe gyrus upward and slightly backward, ending in the lobus parietalis superioris. This incision is
OPERATIVE TECHNIQUE
447
gradually deepened by means of the diathermy cautery, using the cutting and coagulating currents alternately, and its edges retracted by small flange retractors covered with moist lint. The incision is deepened until the dilated lateral ventricle is opened (Fig. 299). The wound can now be retracted sufficiently to enable the surgeon to see the bulging medial wall of the ventricle covered in part by the choroid plexus. If the choroid plexus is well developed and extends over the medial wall of the ventricle
Fig. 298. — Van Wagenen's Approach to the Pineal showing the Outline of the Osteoplastic Flap and the Site of the Incision in the Cortex.
Fig. 299. — Sectional view of the approach to a Pineal Tumour through a dilated lateral
Ventricle.
in the region of the bulging pineal tumour, it may be coagulated with the diathermy point. The medial wall of the ventricle is then gently incised and the pineal tumour exposed and gradually separated from its connections (Fig. 300). Absolute haemostasis is procured, and a small piece of rubber dam is inserted into the incision in the brain for drainage. The dura mater is replaced and held in position by a few anchoring stitches. The osteoplastic flap is accurately put back in its original position, and the scalp united by a double layer of interrupted sutures, and a firm dressing then applied. The drainage wick is removed after twenty-four hours and the stitches on about the tenth day.
448 THE PINEAL ORGAN
Whichever method of operation is adopted, it is a wise precaution to give the patient some post-operative X-ray therapy, as it is impossible to be quite sure that every particle of the tumour has been removed, and pineal tumours for the most part are radiosensitive.
Fig. 300. — Actual Exposure of a Pineal Tumour through the Lateral
Ventricle.
Ventricular puncture may be necessary during convalescence if the intracranial pressure becomes increased.
In some cases where the pineal tumour is very large it may be advisable to perform a partial lobectomy of the occipital lobe in order to give the surgeon a better method of approach.
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Cite this page: Hill, M.A. (2024, April 20) Embryology Book - The Pineal Organ (1940) 31. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_The_Pineal_Organ_(1940)_31
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