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Spinal epidermoid tumors: Will a forgotten complication rise again?
RegionalAnesthesiaand Pain Medicine24(6): 494-496, 1999
Editorial Spinal Epidermoid Tumors: Will a Forgotten Complication Rise Again? Epidermoid tumors of the central nervous system (CNS) are quite rare, composed of epidermal tissue spherically oriented with the keratin layer facing inward, and filled with a caseous substance formed by desquamation of the epidermal tissue. In the 1960s and the 1970s, many reports of spinal epidermoid tumors were reported in the literature. Many cases were of unknown etiologies, probably the result of congenital rests of epidermal cells in the CNS. Although benign in histologic appearance, they behave malignantly because of their location in the spinal canal or cranial vault, proximity to spinal roots, and their propensity to fracture into "daughter" epidermoid tumors that spread distantly in the CNS. Approximately 50% of the reported epidermoid tumors developed several years after a previous lumbar puncture. They were reported during the era in which lumbar punctures were performed with hollow needles, and it was hypothesized that hollow needles took with them a core of epidermal tissue and implanted this tissue into the cerebrospinal fluid. These reports of iatrogenic epidermoid tumors were instrumental in changing practice: the movement from hollow spinal needles to sty!eted spinal needles for the performance of diagnostic or therapeutic lumbar puncture and intrathecal administration of drugs resulted. However, the 1980s saw the popularization of regional anesthesia, and most particularly, caudal epidural anesthesia in children. During the earliest days of this practice, short pediatric caudal and epidural needles were not manufactured, and anesthesiologists who wanted to perform epidural injections in children were forced to improvise in the selection of equipment, using intravenous cannulae such as butterfly needles or the Angiocath to gain entry to the caudal epidural space. Indeed, until manufacturers of regional anesthesia needles and equipment jumped on the pediatric regional anesthesia bandwagon in the 1990s, it was impossible to find styleted epidural Crawford or Tuohy needles. And so, the practice of performing caudal anesthesia with hollow intravenous needles became established and has remained popular among many anesthesiologists. In this issue of the Journal, Goldschneider and Brandom (1) raise a very interesting question: Does the popular performance of caudal block in children with hollow intravenous cannulae reintroduce the risk of epidermoid tumors, which we will only discover after many years of this practice? In their review, they retrieved the needles of 20-gauge i.v. cannulae after performing caudal block in 50 children. They found epidermal tissue in 18% of cases, whereas other tissue of lesser significance was present in another 36% of cases (blood or fat). Does this represent a significant risk in children? Is a change in practice to styleted needles or previous skin puncture warranted as suggested by the authors? Let's review the available evidence. Goldschneider and Brandom have referenced all the important literature dating from 1960 regarding spinal epidermoid tumors. These references (numbered 8-16 in their article) collectively describe 20 cases of spinal epidermoid tumors, 13 of Accepted for publication June 14, 1999.
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which were in children (2-10). Of these 20 cases, 18 epidermoid tumors followed previous lumbar p u n c t u r e (and in m a n y cases multiple diagnostic or therapeutic punctures) during the era of use of nonstyleted needles, and one was spontaneous. The latency b e t w e e n lumbar p u n c t u r e and diagnosis of the spinal tumors ranged from 2-30 years (median, 8 years), except in the case of one child whose t u m o r was diagnosed 3 m o n t h s after lumbar p u n c t u r e and w h o s e t u m o r c o m m u n i c a t e d with a spina bifida occulta. Of the other 18 cases, 17 were subarachnoid in location, and of these, all were extramedullary. M a n n o et al. reported similar data (10). They reviewed 90 further cases of epidermoid tumors, of which 39 followed lumbar punctures. Therefore, it is clear that a lumbar p u n c t u r e with hollow needles subjects patients to a small but finite risk of spinal tumors. But w h a t ,of epidural injection with hollow needles? Is epidural implantation of t u m o r possible? Of the I07 cases described above, all resulted in subarachnoid tumors. In fact, one experimental investigator (l 1) implanted dural tissue in the subarachnoid space, epidural space, and nervous tissue of the CNS of rats, but the epidural tissue did not foster growth of a t u m o r in any of the implantation sites. But not to be ignored is the report of 2 cases by Pear (5) of spinal epidermoid tumors following spinal injection. Remarkably, one was in a 41 -year-old woman, w h o had received a spinal anesthetic 20 years earlier for childbirth and whose t u m o r was epidural. In other words, in the hundreds of reported cases of epidermoid tumors of the CNS and of the b e t w e e n 100 and 200 cases of these tumors following the introduction of spinal needles, only one describes an epidural tumor. Therefore, the risk of epidermoid tumors in children after caudal anesthesia must be e x t r e m e l y remote, perhaps vanishingly so. First, epidural implantation of epidermal tissue is very unlikely. Second, even in the infrequent instance of accidental dural p u n c t u r e in the course of attempting caudal block, the risk of epidermal implantation is also quite small. Is there evidence that prelancing the skin and going t h r o u g h the previously made opening can p r e v e n t the introduction of dermal tissue? Unfortunately, Goldschneider and B r a n d o m did not compare two groups of children undergoing caudal anesthesia, one with previously nicked skin versus a control group comparable to those subjects they did report. Clearly this is the n e x t step. W h e t h e r this or the use of more expensive styleted block needles is to be r e c o m m e n d e d needs to be shown. In the meantime, despite the very r e m o t e risk of causing epidermal CNS tumors, the creation of a skin nick t h r o u g h which the caudal needle is inserted is a small and inexpensive measure to adopt. Elliot J. Krane, M.D.
Department of Anesthesia Stanford University School of Medicine Stanford, California References
1. Goldschneider KR, Brandom BW. The incidence of tissue coring during the performance of caudal injection in children. Reg Anesth Pain Med 1999: 24: 553-556. 2. Gardner DJ, O'Gorman AM, Blundell JE. Intraspinal epidermoid tumour: Late complication of lumbar puncture. CMAJ 1989: 141: 223-225. 3. Halcrow SJ, Crawford PJ, Craft AW. Epidermoid spinal tumour after lumbar puncture. Arch Dis Child 1985: 60: 978-979. 4. Caro PA, Marks HG, Keret D. Intraspinal epidermoid tumors in children: Problems in recognition and imaging techniques for diagnosis. J Pediatr Orthop 1991: II: 288-293. 5. Pear BL. Iatrogenic intraspinal epidermoid sequestration cysts. Radiology i969: 92: 251-254.
Krane
495
496 RegionalAnesthesia and Pain Medicine Voi. 24 No. 6 November-December 1999 6. Shaywitz BA. Epidermoid spinal cord tumors and previous lumbar punctures. J Pediatr 1972: 80: 638-640. 7. Boyd HR. Iatrogenic intraspinal epidermoid: Report of a case. J Neurosurg 1966: 24: 105-107. 8. Batnitzky S, Keucher TR, Mealey J. Iatrogenic intraspinal epidermoid tumors. JAMA 1977: 237: 148-150. 9. McDonald JV, Klump TE. Intraspinal epidermoid tumors caused by lumbar puncture. Arch Neurol 1986: 43: 936-939. 10. Manno NJ, Uihlein A, Kernohan JW. Intraspinal epidermoids. J Neurosurg 1962: 19: 754-765. 11. Van Gilder JC, Schwartz fiG. Growth of dermoids from skin implants to the nervous system and surrounding spaces of newborn rats. J Neurosurg 1967: 26: 14-20.
Editorial Spinal Epidermoid Tumors: Will a Forgotten Complication Rise Again? Epidermoid tumors of the central nervous system (CNS) are quite rare, composed of epidermal tissue spherically oriented with the keratin layer facing inward, and filled with a caseous substance formed by desquamation of the epidermal tissue. In the 1960s and the 1970s, many reports of spinal epidermoid tumors were reported in the literature. Many cases were of unknown etiologies, probably the result of congenital rests of epidermal cells in the CNS. Although benign in histologic appearance, they behave malignantly because of their location in the spinal canal or cranial vault, proximity to spinal roots, and their propensity to fracture into "daughter" epidermoid tumors that spread distantly in the CNS. Approximately 50% of the reported epidermoid tumors developed several years after a previous lumbar puncture. They were reported during the era in which lumbar punctures were performed with hollow needles, and it was hypothesized that hollow needles took with them a core of epidermal tissue and implanted this tissue into the cerebrospinal fluid. These reports of iatrogenic epidermoid tumors were instrumental in changing practice: the movement from hollow spinal needles to sty!eted spinal needles for the performance of diagnostic or therapeutic lumbar puncture and intrathecal administration of drugs resulted. However, the 1980s saw the popularization of regional anesthesia, and most particularly, caudal epidural anesthesia in children. During the earliest days of this practice, short pediatric caudal and epidural needles were not manufactured, and anesthesiologists who wanted to perform epidural injections in children were forced to improvise in the selection of equipment, using intravenous cannulae such as butterfly needles or the Angiocath to gain entry to the caudal epidural space. Indeed, until manufacturers of regional anesthesia needles and equipment jumped on the pediatric regional anesthesia bandwagon in the 1990s, it was impossible to find styleted epidural Crawford or Tuohy needles. And so, the practice of performing caudal anesthesia with hollow intravenous needles became established and has remained popular among many anesthesiologists. In this issue of the Journal, Goldschneider and Brandom (1) raise a very interesting question: Does the popular performance of caudal block in children with hollow intravenous cannulae reintroduce the risk of epidermoid tumors, which we will only discover after many years of this practice? In their review, they retrieved the needles of 20-gauge i.v. cannulae after performing caudal block in 50 children. They found epidermal tissue in 18% of cases, whereas other tissue of lesser significance was present in another 36% of cases (blood or fat). Does this represent a significant risk in children? Is a change in practice to styleted needles or previous skin puncture warranted as suggested by the authors? Let's review the available evidence. Goldschneider and Brandom have referenced all the important literature dating from 1960 regarding spinal epidermoid tumors. These references (numbered 8-16 in their article) collectively describe 20 cases of spinal epidermoid tumors, 13 of Accepted for publication June 14, 1999.
,4 QA
Editorial
•
which were in children (2-10). Of these 20 cases, 18 epidermoid tumors followed previous lumbar p u n c t u r e (and in m a n y cases multiple diagnostic or therapeutic punctures) during the era of use of nonstyleted needles, and one was spontaneous. The latency b e t w e e n lumbar p u n c t u r e and diagnosis of the spinal tumors ranged from 2-30 years (median, 8 years), except in the case of one child whose t u m o r was diagnosed 3 m o n t h s after lumbar p u n c t u r e and w h o s e t u m o r c o m m u n i c a t e d with a spina bifida occulta. Of the other 18 cases, 17 were subarachnoid in location, and of these, all were extramedullary. M a n n o et al. reported similar data (10). They reviewed 90 further cases of epidermoid tumors, of which 39 followed lumbar punctures. Therefore, it is clear that a lumbar p u n c t u r e with hollow needles subjects patients to a small but finite risk of spinal tumors. But w h a t ,of epidural injection with hollow needles? Is epidural implantation of t u m o r possible? Of the I07 cases described above, all resulted in subarachnoid tumors. In fact, one experimental investigator (l 1) implanted dural tissue in the subarachnoid space, epidural space, and nervous tissue of the CNS of rats, but the epidural tissue did not foster growth of a t u m o r in any of the implantation sites. But not to be ignored is the report of 2 cases by Pear (5) of spinal epidermoid tumors following spinal injection. Remarkably, one was in a 41 -year-old woman, w h o had received a spinal anesthetic 20 years earlier for childbirth and whose t u m o r was epidural. In other words, in the hundreds of reported cases of epidermoid tumors of the CNS and of the b e t w e e n 100 and 200 cases of these tumors following the introduction of spinal needles, only one describes an epidural tumor. Therefore, the risk of epidermoid tumors in children after caudal anesthesia must be e x t r e m e l y remote, perhaps vanishingly so. First, epidural implantation of epidermal tissue is very unlikely. Second, even in the infrequent instance of accidental dural p u n c t u r e in the course of attempting caudal block, the risk of epidermal implantation is also quite small. Is there evidence that prelancing the skin and going t h r o u g h the previously made opening can p r e v e n t the introduction of dermal tissue? Unfortunately, Goldschneider and B r a n d o m did not compare two groups of children undergoing caudal anesthesia, one with previously nicked skin versus a control group comparable to those subjects they did report. Clearly this is the n e x t step. W h e t h e r this or the use of more expensive styleted block needles is to be r e c o m m e n d e d needs to be shown. In the meantime, despite the very r e m o t e risk of causing epidermal CNS tumors, the creation of a skin nick t h r o u g h which the caudal needle is inserted is a small and inexpensive measure to adopt. Elliot J. Krane, M.D.
Department of Anesthesia Stanford University School of Medicine Stanford, California References
1. Goldschneider KR, Brandom BW. The incidence of tissue coring during the performance of caudal injection in children. Reg Anesth Pain Med 1999: 24: 553-556. 2. Gardner DJ, O'Gorman AM, Blundell JE. Intraspinal epidermoid tumour: Late complication of lumbar puncture. CMAJ 1989: 141: 223-225. 3. Halcrow SJ, Crawford PJ, Craft AW. Epidermoid spinal tumour after lumbar puncture. Arch Dis Child 1985: 60: 978-979. 4. Caro PA, Marks HG, Keret D. Intraspinal epidermoid tumors in children: Problems in recognition and imaging techniques for diagnosis. J Pediatr Orthop 1991: II: 288-293. 5. Pear BL. Iatrogenic intraspinal epidermoid sequestration cysts. Radiology i969: 92: 251-254.
Krane
495
496 RegionalAnesthesia and Pain Medicine Voi. 24 No. 6 November-December 1999 6. Shaywitz BA. Epidermoid spinal cord tumors and previous lumbar punctures. J Pediatr 1972: 80: 638-640. 7. Boyd HR. Iatrogenic intraspinal epidermoid: Report of a case. J Neurosurg 1966: 24: 105-107. 8. Batnitzky S, Keucher TR, Mealey J. Iatrogenic intraspinal epidermoid tumors. JAMA 1977: 237: 148-150. 9. McDonald JV, Klump TE. Intraspinal epidermoid tumors caused by lumbar puncture. Arch Neurol 1986: 43: 936-939. 10. Manno NJ, Uihlein A, Kernohan JW. Intraspinal epidermoids. J Neurosurg 1962: 19: 754-765. 11. Van Gilder JC, Schwartz fiG. Growth of dermoids from skin implants to the nervous system and surrounding spaces of newborn rats. J Neurosurg 1967: 26: 14-20.