Neurosurgical forum References
1. Corssen G. Holcomb MC, Moustapha L, et al: Alcohol-induced adenolysis of the pituitary gland: a new approach to control of intractable cancer pain. Anesth Analg 56:414-421, 1977 2. Katz J, Levin AB: Treatment of diffuse metastatic cancer pain by instillation of alcohol into the sella turcica. Anesthesiology 46:115121, 1977 3. Moricca G, Colistro F: Hormonal control of malignant tumors, in Walte Davis (ed): Characterization of Human Tumors. Amsterdam: Excerpta Medica, 1973, vol. l, pp 218-232 Multipurpose Valve Shunt
T o THE EDITOR: As a neurosurgeon involved in the development of the multipurpose valve ( M P V ) , I read with interest Dr. Arthur G e r b e r ' s letter to the editor in the November, 1977, issue of the Journal o f Neurosurgery. T h e inadvertent closure of a M P V with " o n - o f f device" is not a malfunction of the valve since the valve could be reopened without difficulty. The problem, I believe, was inappropriate patient selection for use of the " o n - o f f device." The M P V is available with and without the "on-off device" for a good reason. Only a selected group of patients require the device, while the other advantages of the M P V are made available to the general group of patients with hydrocephalus. The most important innovation in the M P V is the anti-siphon valve (ASV). Unfortunately "anti-siphon valve" was a p o o r choice of name since the device simply equilibrates the outlet Of the differential pressure valve (DPV), in this instance the miter valve, with atmospheric pressure. Thus the D P V will work in vivo as calibrated in vitro. Further explanation of the function of the A S V is given by Portnoy, and co-workers .2 The M P V was also designed so that C S F flow can be directed selectively. Compression of the valve " o c c l u d e r " and depression of the reservoir directs C S F distally; compression of the ASV and depression of the reservoir directs C S F proximally. Thus each end of the shunt can be tested separately and any indicator substance (such as radiopaque m e d i u m , isotope) injected into the reservoir can be specifically directed proximally or distally. The " o n - o f f device" was designed for special uses such as: 1) attempting to render J. Neurosurg. / Volume 48 / April, 1978
the patient with hydrocephalus shunt independent by use of the technique developed at New Y o r k University x (intermittent shunt occlusion is used to develop the patient's own cerebrospinal fluid pathways and convert him from a noncompensated to a compensated state), 2) minimizing the post-shunt formation of a subdural h e m a t o m a in patients with craniocerebral disproportion and in particular adult patients with so-called " n o r m a l pressure hydrocephalus," and 3) providing an alternative pathway for the H o f f m a n in-line millipore filter in children with medulloblastoma and hydrocephalus. I f there is not a specific reason for use of the " o n - o f f device" portion of the MPV, then it should not be used. I f the reason is a good one then the neurosurgeon should accept the known risk that the device can be inadvertently turned off. A simpler alternative to changing the valve is to teach the mother to check the valve for potency if any unusual s y m p t o m s occur. The function of the device is to occlude the shunt. When the M P V was being developed we tried to " h a v e our cake and eat it too." Initially the device was set to re-open at an intracranial pressure of 60 to 100 cm H20. This did not work out well, since any cough or cry re-opened the device. The device had to be set at at least 150 cm H 2 0 to assure continued closure. Even at this level, occasional transient increases in intracranial pressure pop open the device. Because of the variations that can occur in the molding of silicone rubber, I a m not surprised to note that the device Dr. Gerber tested opened at greater than 225 cm H20. H e did not, however, have any difficulty in re-opening the device percutaneously, and that is how it was designed. HAROLD D. PORTNOY, M.D. Bloomfield Hills, Michigan References
1. Epstein F, Hochwald G, RansohoffJ: A volume control system for the treatment of hydrocephalus: laboratory and clinical experience. J Neurosnrg 38:282-287, 1973 2. Portnoy HD, Tripp L, Croissant PD: Hydrodynamics of shunt valves. Childs Brain 2:242-256, 1976
RESPONSE: In reply to Dr. P o r t n o y ' s letter discussing the multipurpose valve, I a m in full agreement with him. The case was not one of malfunction of the multipurpose valve shunt. 667
Neurosurgical forum Without knowing the intentions of the neurosurgeon who implanted it, it would also be wrong to call it a misapplication of the device. Perhaps a more appropriate title for my letter would have been "Dangers Inherent in the On-Off Device for CSF Shunts." As Dr. Portnoy states in his letter and I stated in my original letter, this device should be used with caution. I would still recommend that the literature packaged with the on-off device state its opening pressure. The multipurpose valve does have a place in the neurosurgical armamentarium in the battle against hydrocephalus. Awareness of the dangers inherent in the use of this shunt will remind neurosurgeons to use the device in those patients for whom its features are specifically indicated. ARTHURM. GERBER,M.D. Toledo, Ohio
Microadenectomy or Microhypophysectomy T o THE EDITOR: I wish to comment on the recent article on transsphenoidal microhypophysectomy in acromegaly (U HS, Wilson CB, Tyrrell JB: Transsphenoidal microhypophysectomy in acromegaly. J Neurosurg 47.'840-852, December, 1977). The authors should be congratulated for this excellent article on the treatment of acromegaly using the open transsphenoidal approach and microsurgical technique. Since we introduced the method in early 1960, it is gratifying to encounter several other groups who are convinced of its superior effectiveness. I have only a minor critical comment concerning the use of the proper name for describing the surgical method. " M i c r o h y p o p h y s e c t o m y " refers to ablation of the normal pituitary gland, as used in the palliative treatment of advanced breast cancer or diabetic retinopathy. On the contrary, in the treatment of acromegaly, all effort is made to preserve the normal gland while only the tumor is selectively removed. Therefore the procedure should be called "microadenectomy." JULESHARD~, M.D. Montreal, Quebec
Ankylosing Spondylitis and Sciatica T o THE EDITOR: In a recent report (Bingham WF: The role of HLA B27 in the diagnosis and management of low-back pain 668
and sciatica. J Neurosurg 47:561-566, October, 1977), Bingham discussed the value of typing for H L A B27 in patients hospitalized with low-back pain and sciatica before using invasive diagnostic procedures. HLA B27, one of the histocompatibility antigens that participates in cell interactions concerned with immunity, is present in only 7% of Caucasians but has been found in 96% of patients with ankylosing spondylitis (AS). Since AS usually presents with low-back pain, as well as sciatica in 10%, it can mimic the syndrome of ruptured lumbar intervertebral disc. Thus, tissue typing for HLA B27 would seem to be a good differentiator. However, H L A B27 typing alone is not sufficient; only 20% of Caucasians with HLA B27 ever develop definite AS. It is as though AS is the result of an altered immune response of B27-positive individuals to infection (venereal?) by an unknown organism. Because 20% of the population often has lowback pain, back pain in a B27-positive patient is equally likely to be due to some other condition as to AS. Furthermore, since AS occurs in, at most, 1.4% of Caucasians (20% of 7%), most patients with back pain do not have AS, and B27 screening would thus be of low yield. Is there a subset of patients in whom H L A B27 typing would frequently prevent unnecessary myelography? Patients with neurological signs or a crossed sciatic sign would be excluded from this subset, which would contain a large proportion of patients with lowback pain only, especially if associated with morning stiffness. Alternating sciatica, systemic signs such as fever, weight loss, anemia, and elevated sedimentation rate also increase the suspicion of AS. Suspicion of sacroiliitis in x-ray studies might also call for B27 typing. So far, the primary value of HLA B27 typing has been to increase our awareness of AS by showing that the disease is 100 times more prevalent than previously suspected and occurs equally in men and women. The association of H L A B27 and AS is significantly lower in black Americans. With increasing awareness, undiagnosed cases have been found by identifying previously unreported changes in the sacroiliac joints, and we should now pay more attention to this area when reading spine films. Also, isotope bone scan may be positive before sacroiliitis is visible
J. Neurosurg. / Volume 48 / April, 1978
1. Corssen G. Holcomb MC, Moustapha L, et al: Alcohol-induced adenolysis of the pituitary gland: a new approach to control of intractable cancer pain. Anesth Analg 56:414-421, 1977 2. Katz J, Levin AB: Treatment of diffuse metastatic cancer pain by instillation of alcohol into the sella turcica. Anesthesiology 46:115121, 1977 3. Moricca G, Colistro F: Hormonal control of malignant tumors, in Walte Davis (ed): Characterization of Human Tumors. Amsterdam: Excerpta Medica, 1973, vol. l, pp 218-232 Multipurpose Valve Shunt
T o THE EDITOR: As a neurosurgeon involved in the development of the multipurpose valve ( M P V ) , I read with interest Dr. Arthur G e r b e r ' s letter to the editor in the November, 1977, issue of the Journal o f Neurosurgery. T h e inadvertent closure of a M P V with " o n - o f f device" is not a malfunction of the valve since the valve could be reopened without difficulty. The problem, I believe, was inappropriate patient selection for use of the " o n - o f f device." The M P V is available with and without the "on-off device" for a good reason. Only a selected group of patients require the device, while the other advantages of the M P V are made available to the general group of patients with hydrocephalus. The most important innovation in the M P V is the anti-siphon valve (ASV). Unfortunately "anti-siphon valve" was a p o o r choice of name since the device simply equilibrates the outlet Of the differential pressure valve (DPV), in this instance the miter valve, with atmospheric pressure. Thus the D P V will work in vivo as calibrated in vitro. Further explanation of the function of the A S V is given by Portnoy, and co-workers .2 The M P V was also designed so that C S F flow can be directed selectively. Compression of the valve " o c c l u d e r " and depression of the reservoir directs C S F distally; compression of the ASV and depression of the reservoir directs C S F proximally. Thus each end of the shunt can be tested separately and any indicator substance (such as radiopaque m e d i u m , isotope) injected into the reservoir can be specifically directed proximally or distally. The " o n - o f f device" was designed for special uses such as: 1) attempting to render J. Neurosurg. / Volume 48 / April, 1978
the patient with hydrocephalus shunt independent by use of the technique developed at New Y o r k University x (intermittent shunt occlusion is used to develop the patient's own cerebrospinal fluid pathways and convert him from a noncompensated to a compensated state), 2) minimizing the post-shunt formation of a subdural h e m a t o m a in patients with craniocerebral disproportion and in particular adult patients with so-called " n o r m a l pressure hydrocephalus," and 3) providing an alternative pathway for the H o f f m a n in-line millipore filter in children with medulloblastoma and hydrocephalus. I f there is not a specific reason for use of the " o n - o f f device" portion of the MPV, then it should not be used. I f the reason is a good one then the neurosurgeon should accept the known risk that the device can be inadvertently turned off. A simpler alternative to changing the valve is to teach the mother to check the valve for potency if any unusual s y m p t o m s occur. The function of the device is to occlude the shunt. When the M P V was being developed we tried to " h a v e our cake and eat it too." Initially the device was set to re-open at an intracranial pressure of 60 to 100 cm H20. This did not work out well, since any cough or cry re-opened the device. The device had to be set at at least 150 cm H 2 0 to assure continued closure. Even at this level, occasional transient increases in intracranial pressure pop open the device. Because of the variations that can occur in the molding of silicone rubber, I a m not surprised to note that the device Dr. Gerber tested opened at greater than 225 cm H20. H e did not, however, have any difficulty in re-opening the device percutaneously, and that is how it was designed. HAROLD D. PORTNOY, M.D. Bloomfield Hills, Michigan References
1. Epstein F, Hochwald G, RansohoffJ: A volume control system for the treatment of hydrocephalus: laboratory and clinical experience. J Neurosnrg 38:282-287, 1973 2. Portnoy HD, Tripp L, Croissant PD: Hydrodynamics of shunt valves. Childs Brain 2:242-256, 1976
RESPONSE: In reply to Dr. P o r t n o y ' s letter discussing the multipurpose valve, I a m in full agreement with him. The case was not one of malfunction of the multipurpose valve shunt. 667
Neurosurgical forum Without knowing the intentions of the neurosurgeon who implanted it, it would also be wrong to call it a misapplication of the device. Perhaps a more appropriate title for my letter would have been "Dangers Inherent in the On-Off Device for CSF Shunts." As Dr. Portnoy states in his letter and I stated in my original letter, this device should be used with caution. I would still recommend that the literature packaged with the on-off device state its opening pressure. The multipurpose valve does have a place in the neurosurgical armamentarium in the battle against hydrocephalus. Awareness of the dangers inherent in the use of this shunt will remind neurosurgeons to use the device in those patients for whom its features are specifically indicated. ARTHURM. GERBER,M.D. Toledo, Ohio
Microadenectomy or Microhypophysectomy T o THE EDITOR: I wish to comment on the recent article on transsphenoidal microhypophysectomy in acromegaly (U HS, Wilson CB, Tyrrell JB: Transsphenoidal microhypophysectomy in acromegaly. J Neurosurg 47.'840-852, December, 1977). The authors should be congratulated for this excellent article on the treatment of acromegaly using the open transsphenoidal approach and microsurgical technique. Since we introduced the method in early 1960, it is gratifying to encounter several other groups who are convinced of its superior effectiveness. I have only a minor critical comment concerning the use of the proper name for describing the surgical method. " M i c r o h y p o p h y s e c t o m y " refers to ablation of the normal pituitary gland, as used in the palliative treatment of advanced breast cancer or diabetic retinopathy. On the contrary, in the treatment of acromegaly, all effort is made to preserve the normal gland while only the tumor is selectively removed. Therefore the procedure should be called "microadenectomy." JULESHARD~, M.D. Montreal, Quebec
Ankylosing Spondylitis and Sciatica T o THE EDITOR: In a recent report (Bingham WF: The role of HLA B27 in the diagnosis and management of low-back pain 668
and sciatica. J Neurosurg 47:561-566, October, 1977), Bingham discussed the value of typing for H L A B27 in patients hospitalized with low-back pain and sciatica before using invasive diagnostic procedures. HLA B27, one of the histocompatibility antigens that participates in cell interactions concerned with immunity, is present in only 7% of Caucasians but has been found in 96% of patients with ankylosing spondylitis (AS). Since AS usually presents with low-back pain, as well as sciatica in 10%, it can mimic the syndrome of ruptured lumbar intervertebral disc. Thus, tissue typing for HLA B27 would seem to be a good differentiator. However, H L A B27 typing alone is not sufficient; only 20% of Caucasians with HLA B27 ever develop definite AS. It is as though AS is the result of an altered immune response of B27-positive individuals to infection (venereal?) by an unknown organism. Because 20% of the population often has lowback pain, back pain in a B27-positive patient is equally likely to be due to some other condition as to AS. Furthermore, since AS occurs in, at most, 1.4% of Caucasians (20% of 7%), most patients with back pain do not have AS, and B27 screening would thus be of low yield. Is there a subset of patients in whom H L A B27 typing would frequently prevent unnecessary myelography? Patients with neurological signs or a crossed sciatic sign would be excluded from this subset, which would contain a large proportion of patients with lowback pain only, especially if associated with morning stiffness. Alternating sciatica, systemic signs such as fever, weight loss, anemia, and elevated sedimentation rate also increase the suspicion of AS. Suspicion of sacroiliitis in x-ray studies might also call for B27 typing. So far, the primary value of HLA B27 typing has been to increase our awareness of AS by showing that the disease is 100 times more prevalent than previously suspected and occurs equally in men and women. The association of H L A B27 and AS is significantly lower in black Americans. With increasing awareness, undiagnosed cases have been found by identifying previously unreported changes in the sacroiliac joints, and we should now pay more attention to this area when reading spine films. Also, isotope bone scan may be positive before sacroiliitis is visible
J. Neurosurg. / Volume 48 / April, 1978
