In closing I would like to state that I believe that with stereocryohypophysectomy we have a simple, effective technique which can be utilized to alter pituitary function. It can be performed under local anesthesia and, is a safe and effective method for aid in the control of diabetic retinopathy

Collins, William F., Jr.

VCU Scholars Compass

Cryosurgery of the Pituitary Gland* WILLIAM F. COLLINS, JR. Department of Surgery, Medical College of Virginia, Richmond I have been asked to discuss neurosurgical methods of altering pituitary function as a means of controlling diabetic retinopathy. Partial or total destruction of the pituitary gland can only be affec-tively utilized in the therapy of the complications of diabetes if it can be accomplished with low mor-bidity and mortality. My experience with hypophyseal stalk section and hypophysectomy by frontal craniot-omy for palliation of carcinoma of the breast led me to believe that these methods would have low morbidity and mortality in the dia-betic patient. However, in contrast to the older, apparently frail woman with metastatic carcinoma of the breast who had little difficulty un-dergoing craniotomy, the diabetic not only had difficulty with the craniotomy but also had significant morbidity with prolonged general anesthesia. Any complications of either anesthesia or craniotomy of-ten led to a fatal outcome or severe morbidity. Because of this morbid-ity and mortality, I first attempted, as Dr. Pearson has mentioned, ster-eotaxic hypophysectomy with Yt-trium••, a radioactive isotope. The ease with which the isotope could be placed in the gland with uni-formly high incidence of total or near total destruction of the gland Jed to the series of patients which Dr. Pearson has discussed . A prob-lem in the long-term followup with these patients, namely a 10% to 12% incidence of rhinorrhea and *Study supported in part by U. S. Public Health Service grant 1 ROI CA08281-01. 58 a smaller percentage of late radia-tion changes in surrounding neural structures, induced our division of neurological surgery at the Medical College of Virginia to attempt an-other method for producing de-structive lesions in the pituitary gland. The method had to be sim-ple in application, preferably able to be done under local anesthesia, and should be relatively innocuous to the ocular motor nerve, the optic nerves, and the hypothalamus, which lie close to the pituitary gland. Our reason for picking ster-eotaxic cryosurgery was the unique position of the pituitary gland and the reversibility of a controlled cold lesion . The gland is surrounded by bone on its inferior surface, the cavernous sinus on its lateral sur-faces , and cerebrospinal fluid on its superior and posterior surfaces. The areas containing the neural structures we wished to protect were, therefore, isolated from the gland by either cerebrospinal fluid or blood, substances capable of rapid heat exchange. The ocular motor and optic nerves are known to cease functioning at approxi-mately 10 C, but do not sustain ir-reversible damage until cooled 10 to 15 C below this. These factors seemed ideal for cryosurgical tech-niques. TECHNIQUE Cryohypophysectomy at the Medical College of Virginia is done under local lidocaine (Xylocaine) anesthesia with a modification of the Rand-Wells stereotaxic head holder. The coiling instrument is the Cooper-Linde cryosurgical probe which utilizes liquid nitrogen as the cooling agent. For total hy-pophysectomy we use the 4.4 mm probe and for partial lesions the 2.2 mm probe. The probe consists of three unicentric tubes with an exposed silver tip. The inner tube delivers the nitrogen, the middle tube exhausts it, and the outer tube is a vacuum insulator. After posi-tioning the head with x-ray control, the nasal mucosa is anesthetized and the probe guide is positioned at the floor of the sphenoid sinus. An opening is then drilled through the floor of the sinus and the probe guide advanced to the floor of the sella. After checking the position by x-ray, the floor of the sella is opened with a drill, the capsule of the pituitary gland incised, and the the probe placed in the gland. The usual probe position is just below the equator of the gland and about 2 to 3 mm lateral to the midline. The low position in the gland is to minimize cooling of the pituitary stalk in order to avert significant diabetes insipidus, and the medial position is to protect the ocular motor and optic nerves. Liquid nitrogen is circulated through the probe with thermistor control of the probe temperature, and fre-quent checks of optic and ocular motor function are made while the temperature is lowered to -180 C. Since there is considerable differ-ence between non-functioning of a nerve and damage, any evidence of malfunction signals the operator to rewarm and reposition the probe. A second lesion is placed in the gland 2 to 3 mm on the opposite MCV QUARTERLY 2(1): 58-59, 1966 CRYOSURGERY OF THE PITUITARY GLAND side of the midline by either slant-ing the probe across the midline or using the opposite nostril. Each le-sion takes approximately 10 min of cooling. RESULTS We have performed cryohy-pophysectomies in 35 patients with no mortality. In six of the patients with carcinoma of the breast who subsequently died of their disease, histological section of the sella has failed to reveal any evidence of re-maining pituitary gland. Complete endocrine evaluation has been done pre- and postoperatively on all the patients, and except for a few pa-tients in whom partial destruction was planned, these tests indicate no functioning pituitary. The morbid-ity has consisted of two cases of rhinorrhea, both of which occurred in the immediate postoperative pe-riod and have healed spontaneously. This is in contrast to the delayed onset of rhinorrhea in the radiation pituitary abalation cases. It is dif-ficult at this time to state that stereocryohypophysectomy is supe-rior to stereo-Yttrium hypophysec-tomy, since both have low rate of immediate complications. As time has passed, the lack of delayed com-plications in the cryosurgical cases appears to favor that technique. In closing I would like to state that I believe that with stereo-cryohypophysectomy we have a simple, effective technique which can be utilized to alter pituitary function. It can be performed un-der local anesthesia and, is a safe and effective method for aid in the control of diabetic retinopathy. 59 GOOD TEACHING* The growing emphasis on re-search, the availability to academic personnel of external grants which support a wide variety of activities other than teaching, the lure of "freedom from routine duties" (al-though teaching should never de-teriorate into a routine duty), and the use by some institutions of criteria for advancement that seem to overemphasize research or even that superficial evidence, publica-tion-all of these factors have of late tended to underemphasize the role of good teaching. But what is a good teacher? Is he the popular teacher? Is he the one who gives flashy and spectacu-lar lectures? Is he the one whose students average highest on de-partmental exams? Is he the one whose presentations are so tidy that note-taking is easy? Is he the good fellow with the best jokes? Is he a disciplinarian, or is he lax about standards and performance? Does he trouble the stupid but in-spire the really able? The answers all depend on the orientation of the one who replies. By all odds the most popular phys-ics teacher I have ever known was a sweet gentleman who just could not bring himself to fail the letters and arts students who flocked to his sections to work off their sci-ence requirements. One of the most popular lecturers in a social science subject I have met with was a man whose smoothly pre-sented lectures were almost as well organized as the textbook. He was famous for finishing every lecture with a polished phrase exactly as the bell rang. On the other hand, one of my own great teachers in high school was an exceedingly strict Latin teacher. Perhaps he was not loved, but he certainly was respected-and 55 years later I can still scan Vergil. My very greatest university teacher stopped one day, in the middle of a long and complex proof of a fundamental theorem in potential theory, looked at the *Editorial, Science, Vol. 151, 18 March 1966, p . 1335. 60 confused and badly written mess he had put on the blackboard, said "Well, boys, something is wrong" -and walked out, leaving us to save ourselves . So before you decide whether a teacher is good, ask, good for what? The purposes should vary greatly, from the broad intent of survey courses and the exploratory excitement of introductory courses to the stimulating depth of grad-uate courses. Is the criterion of goodness the mechanical success with which information is trans-mitted, the sympathy and warmth with which a young mind is led to unfold-or the influence a great character can have on the whole life of a student? I do not think a teacher can be judged by weighing publications, but I also think no teacher can be successful unless he is alert to the new knowledge in his field. In many instances it is absurd to ex-pect a teacher to be a scholarly producer of original research; but it is fatal not to require him to be alive to his subject. I am sure that some evaluations of teachers by students have been made with serious purpose, but I profoundly disbelieve the results. It will not even work to ask alumni -presumably wiser, surely older, and hopefully more eclectic-which teachers they remember with greatest admiration. I think the only useful judgment concerning university teachers comes from their immediate work-ing colleagues. The administrators should be aware of student opinion, of course, and in some cases it may be useful. But fellow teachers, through their skillful and inti-mately informed judgments, will come nearest to recognizing good teaching. The immediate col-leagues of a teacher will know what the students really think, for they will have obtained this infor-mation in effective informal ways, will have available the evidence of student records, will be aware of the general community opinion, and will have put all this informa-tion through the sieve of their own competence. WARREN WEAVER, Alfred P. Sloan Foundation, New York 

Cryosurgery of the Pituitary Gland

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Cryosurgery of the Pituitary Gland

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