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Successful aqueductal plasty and stenting for tectal plate tumor after failed third ventriculostomy
Neoplasm
Successful Aqueductal Plasty and Stenting for Tectal Plate Tumor after Failed Third Ventriculostomy: A Case Report Ketan R. Bulsara, M.D., Alan T. Villavicencio, M.D., Anand J. Shah, B.S., Matthew J. McGirt, B.S., and Timothy M. George, M.D. Pediatric Neurosurgery Service, Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina
Bulsara KR, Villavicencio AT, Shah AJ, McGirt MJ, George TM. Successful aqueductal plasty and stenting for tectal plate tumor after failed third ventriculostomy: a case report. Surg Neurol 2003;59:58 – 62. BACKGROUND
Tectal region tumors can lead to hydrocephalus secondary to aqueductal compression. Surgical options for these patients include extracranial cerebrospinal fluid (CSF) shunts, third ventriculostomy, and/or aqueductal plasty. In cases of third ventriculostomy failure, the accepted alternative is an extracranial CSF shunt. We report a patient in whom a repeat third ventriculostomy with aqueductal plasty and stenting was successful after a failed initial third ventriculostomy. CASE PRESENTATION
A 12-year-old patient with hydrocephalus secondary to a tectal tumor presented with headaches and blurry vision. She had no focal neurologic findings. She underwent a third ventriculostomy. Five months after the procedure she had recurrence of her symptoms. Therefore, she underwent a secondary third ventriculostomy with aqueductal plasty and stenting. She has been symptom-free for 1 year.
Although extracranial shunts are commonly used to treat these patients, results have been disappointing. With advancements in neuroendoscopic techniques, there has been increased enthusiasm for third ventriculostomy and aqueductal plasty [3,5, 10,22,23]. Both these techniques provide a more natural route for CSF flow, while maintaining physiologic pressure states within the cranial cavity [17,18]. The third ventriculostomy success rate is similar to that of CSF shunts and it has a failure rate of 30% [3,22]. Favorable results with endoscopic aqueductal plasty have been reported, but are rare in the literature [16,17,22,27]. We report a patient with obstructive hydrocephalus because of a tectal tumor in whom third ventriculostomy initially failed, but she was successfully treated with a combination of secondary third ventriculostomy, aqueductal plasty, and stenting.
CONCLUSION
Aqueductal plasty with stenting may be an alternative to CSF shunts in some patients with hydrocephalus because of aqueductal compression resulting from tectal tumors. © 2003 Elsevier Science Inc. KEY WORDS
Aqueductal plasty, endoscopic, tectal glioma, third ventriculostomy.
eoplasms of the tectum are a potential cause of hydrocephalus [7,8,13,15,19,26]. Potential treatment options include shunt placement, third ventriculostomy, and aqueductal plasty [17,21,22].
N
Address reprint requests to: Dr Timothy M. George, P.O. Box 3272, Duke University Medical Center, Division of Neurosurgery, Durham, NC 27705. Received XX, 2002; accepted XX, 2002. 0090-3019/03/$–see front matter doi:10.1016/S0090-3019(02)00942-4
Case Presentation A 12-year-old patient presented with hydrocephalus, headaches, and blurry vision because of aqueductal compression from a tectal tumor (Figure 1). She underwent a third ventriculostomy with resolution of her symptoms. A follow-up magnetic resonance imaging (MRI) scan 2 weeks after the procedure revealed decreased ventricular size with flow through the third ventriculostomy (Figure 2). Five months after the procedure, the patient had gradual recurrence of her symptoms. A head computed tomography (CT) revealed increased ventricular size (Figure 3A). Subsequently she underwent a repeat third ventriculostomy as previously described [29]. Utilizing a 1.2-mm semi-rigid neuroen© 2003 by Elsevier Science Inc. 360 Park Avenue South, New York, NY 10010 –1710
Successful Aqueductal Plasty and Stenting
Surg Neurol 2003;59:58 – 62
59
past experience, this has led to poor patency of the third ventriculostomy. Because of these concerns, aqueductal plasty was performed at the same operation. The aqueduct was identified and noted to be occluded. This was opened with gentle saline irrigation and blunt dissection with the tip of the endoscope, after which the fourth ventricle was entered. A PS Medical cathether with side slits was placed as a stent from the lateral ventricles to the fourth ventricle (Figure 3B-D, 4). The catheter was attached to a ventricular reservoir that was attached to the skull to hold it in place. The other reason for using the reservoir was to establish percutaneous access to the ventricular system should emergency decompression be needed. Postoperatively, the patient did well and was discharged home on postoperative day one. At 1-year followup, she was doing well with no evidence of hydrocephalus.
1
Sagittal T1-weighted MRI scan immediately after third ventriculostomy. Note the ventriculomegaly.
doscope, the previous third ventriculostomy site was identified. This had healed over completely. A 1-cm opening was made in the floor of the third ventricle as previously described [29]. In cases of successful third ventriculostomy we have noted that the intracranial pressure decreases by about one third. This did not happen in our patient. In our
2
Axial MRI scan reveals decreased ventricular size after third ventriculostomy.
Discussion Dandy was the first to report aqueduct reconstruction. The mortality was significant with open procedures and therefore this was largely abandoned [22]. The preferred method of treatment for patients with hydrocephalus resulting from aqueductal stenosis became CSF shunts. However, shunts are associated with a high failure rate [1,2,20,24]. With improvements in neuroendoscopic equipment and techniques, third ventriculostomies have become a viable option for the management of hydrocephalus resulting from aqueductal compression [3,12,14,28,29]. The failure rate for third ventriculostomies approaches 30%, which is similar to that of shunts [3,22]. The most common cause of delayed failure is obstruction of the third ventriculostomy stoma because of proliferation of gliotic tissue [4]. This is also a problem with aqueductal plasty. It has been known since the time of Dandy that “strictures of the aqueduct of Sylvius recur after any attempt to restore the lumen” [6]. This high rate of reocclusion is the most common complication associated with this procedure. Most series report no significant morbidity or mortality associated with aqueductal plasty [17,11,25]. Attempts to keep the aqueduct open with stents have resulted in improved outcomes. Stenting with suboccipital craniotomies has a success rate of 59%, while the use of percutaneous techniques has resulted in a 79% success rate [22]. Currently, no significant morbidity has been reported with endoscopic aqueductal stent place-
60
Surg Neurol 2003;59:58 – 62
Bulsara et al
A: Axial CT scan of the brain reveals increased ventricular size. B-D: Immediate scan after secondary third ventriculostomy and aqueductal stenting. The stent courses through the lateral ventricles to the fourth via the aqueduct. It is attached at the skull to a ventricular reservoir.
3
ment. There appears to be a minimal risk of stent migration [27]. Only mild complications such as transient dysconjugate eye movements have been reported [7,9]. Traditionally, patients in whom endoscopic third ventriculostomy with or without aqueductal plasty fails undergo shunt placement. We report that aqueductal plasty may be a useful adjunct to third ventriculostomy if significant intracranial pressure decreases are not seen after third ventriculostomy. It may be a viable alternative to shunt placement. In our experience, aqueductal plasty for tectal tumors is not technically difficult. Our experience
suggests that the failure of intracranial pressure to decrease by about one third after third ventriculostomy may predict poor patency of the third ventriculostomy. These patients may benefit from aqueductal plasty and possible stenting. Congenital aqueductal stenosis and Dandy-Walker malformation, however, pose a more significant technical challenge. The aqueduct in these patients is often difficult to dilate, increasing the risk of hemorrhage and adverse stent passes into the brainstem. Long-term follow-up and future prospective studies are needed to determine the efficacy of secondary third ventriculostomies and aqueductal plasty with stenting.
Successful Aqueductal Plasty and Stenting
Cathether placed as a stent from the lateral ventricles to the fourth ventricle. Tectal glioma and narrowed aqueduct depicted.
4
REFERENCES 1. Abu-Dalu PD, Pode D, Hadani M, Sahar A. Colonic complications of ventriculoperitoneal shunts. Neurosurgery 1983;13:167–9. 2. Choudhury AR. Avoidable factors that contribute to the complications of ventriculoperitoneal shunt in childhood hydrocephalus. Childs Nerv Syst 1990;6: 346 –9. 3. Brockmeyer DAK, Abtin K, Carey L, Walker M. Endoscopic third ventriculostomy: an outcome analysis. Pediatr Neurosurg 1998:236 –40. 4. Cinalli G, Sainte-Rose C, Chumas P, et al. Failure of third ventriculostomy in the treatment of aqueductal stenosis in children. J Neurosurg 1999;90(3):448 –54. 5. Dalrymple SJ, Kelly PJ. Computer-assisted stereotactic third ventriculostomy in the management of noncommunicating hydrocephalus. Stereotact Funct Neurosurg 1992;59:105–10. 6. Dandy DE. An operative procedure for hydrocephalus. Bull Johns Hopkins Hosp 1922;33:189 –90. 7. Edwards MS, Hudgin RJ, Wilson CB, Levin VA, Wara WM. Pineal region tumors in children. J Neurosurg 1986;68:689 –97. 8. Flamm ES, Rovit RL, Kricheff II, Ransohoff J. Periaqueductal neoplasms and vascular malformations. NY State J Med 1972;72:2623–8. 9. Gaab MR, Schroeder HWS. Neuroendoscopic approach to intraventricular lesions. J Neurosurgery 1998;88:496 –505. 10. Goumnerova LC, Frim D. Treatment of hydrocephalus with third ventriculocisternostomy: outcome and CSF flow patterns. Pediatr Neurosurg 1997;32(6):1043–7. 11. Hamanda H, Hayashi N, Endo S, Kurimoto M, Hirashima Y, Takuku A. Endoscopic aqueductal plasty via the fourth ventricle through the cerebellar hemisphere under navigating system guidance— technical note. Neurologia Medico-Chirurigica 1999; 39:950 –2.
Surg Neurol 2003;59:58 – 62
61
12. Hopf NJ, Grunert P, Fries G, Resch K, Perneczky A. Endoscopic third ventriculostomy: outcome analysis of 100 consecutive procedures. Neurosurgery 1999; 44(4):795–803. 13. Pool LJ. Gliomas of the region of the brain stem. J Neurosurg 1968;29:164 –7. 14. Jones RF, Stening WA, Brydon M. Endoscopic third ventriculostomy. Neurosurgery 1990;26:86 –92. 15. Ho KL. Tumors of the cerebral aqueduct. Cancer 1982;49:154 –62. 16. Manwaring KH, Fritsch M. Endoscopic aqueductal stenting as an option for obstructive hydrocephalus [abstract]. Neurosurgery 1998;43:712–3. 17. Oka K, Yamamoto M, Ikeda K, Tomonaga M. Flexible endoneurosurgical therapy for aqueductal stenosis. Neurosurgery 1993;33(2):236 –42. 18. Oka K, Kin Y, Go Y, et al. Neuroendoscopic approach to tectal tumors: a consecutive series. J Neurosurg 1999;91(6):964 –70. 19. Pendl G, Vorkapic P, Koniyama M. Microsurgery of midbrain lesions. Neurosurgery 1990;26:641–8. 20. Piatt JH, Carlson C. A search for determinants of cerebrospinal fluid shunt survival: retrospective analysis of a 14-year institutional experience. Pediatr Neurosurg 1993;19:233–42. 21. Pollack IF, Pang D, Albright AL. The long-term outcome in children with late-onset aqueductal stenosis resulting from benign intrinsic tectal tumors. J Neurosurg 1994;80(4):681–8. 22. Schroeder HW, Gaab MR. Endoscopic aqueductoplasty. Neurosurgery 1999;45(3):508 –14. 23. Schwartz TH, Yoon SS, Cutruzzola FW, Goodman RR. Third ventriculostomy: post-operative ventricular size and outcome. Minim Invasive Neurosurg 1996;39: 122–9. 24. Sekhar LN, Moosey J, Guthkelch AN. Malfunctioning ventriculoperitoneal shunts: clinical and pathological features. J Neurosurg 1982;56:411–6. 25. Shin M, Morita A, Asano S, Ueki K, Kirino T. Neuroedoscopic aqueductal stent placement procedure for isolated fourth ventricular shunt placement. J Neurosurg 2000;92:1036 –9. 26. Steinbok P, Boyd MC. Periaqueductal tumor as a cause of late-onset aqueductal stenosis. Childs Nerv Syst 1987;3:170 –4. 27. Teo CMS, Cherny WB, Burson T. Surgical options in the management of the trapped fourth ventricle [abstract]. J Neurosurg 1996;84:356a. 28. Tuli S, Alshail E, Drake J. Third ventriculostomy versus cerebrospinal fluid shunt as a first procedure in pediatric hydrocephalus. Pediatr Neurosurg 1999;30: 11–5. 29. Wellons JC, Bagley CA, George TM. A simple and safe technique for endoscopic third ventriculocisternostomy. Pediatr Neurosurg 1999;30(4):219 –23.
COMMENTARY
Bulsara et al describe a case of a child with a tectal tumor treated initially with a third ventriculostomy, which was successful for a while. Subsequently, a second procedure was performed that included reopening the third ventriculostomy, doing an aqueductal plasty, and placing a stent. It is not clear
Successful Aqueductal Plasty and Stenting for Tectal Plate Tumor after Failed Third Ventriculostomy: A Case Report Ketan R. Bulsara, M.D., Alan T. Villavicencio, M.D., Anand J. Shah, B.S., Matthew J. McGirt, B.S., and Timothy M. George, M.D. Pediatric Neurosurgery Service, Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina
Bulsara KR, Villavicencio AT, Shah AJ, McGirt MJ, George TM. Successful aqueductal plasty and stenting for tectal plate tumor after failed third ventriculostomy: a case report. Surg Neurol 2003;59:58 – 62. BACKGROUND
Tectal region tumors can lead to hydrocephalus secondary to aqueductal compression. Surgical options for these patients include extracranial cerebrospinal fluid (CSF) shunts, third ventriculostomy, and/or aqueductal plasty. In cases of third ventriculostomy failure, the accepted alternative is an extracranial CSF shunt. We report a patient in whom a repeat third ventriculostomy with aqueductal plasty and stenting was successful after a failed initial third ventriculostomy. CASE PRESENTATION
A 12-year-old patient with hydrocephalus secondary to a tectal tumor presented with headaches and blurry vision. She had no focal neurologic findings. She underwent a third ventriculostomy. Five months after the procedure she had recurrence of her symptoms. Therefore, she underwent a secondary third ventriculostomy with aqueductal plasty and stenting. She has been symptom-free for 1 year.
Although extracranial shunts are commonly used to treat these patients, results have been disappointing. With advancements in neuroendoscopic techniques, there has been increased enthusiasm for third ventriculostomy and aqueductal plasty [3,5, 10,22,23]. Both these techniques provide a more natural route for CSF flow, while maintaining physiologic pressure states within the cranial cavity [17,18]. The third ventriculostomy success rate is similar to that of CSF shunts and it has a failure rate of 30% [3,22]. Favorable results with endoscopic aqueductal plasty have been reported, but are rare in the literature [16,17,22,27]. We report a patient with obstructive hydrocephalus because of a tectal tumor in whom third ventriculostomy initially failed, but she was successfully treated with a combination of secondary third ventriculostomy, aqueductal plasty, and stenting.
CONCLUSION
Aqueductal plasty with stenting may be an alternative to CSF shunts in some patients with hydrocephalus because of aqueductal compression resulting from tectal tumors. © 2003 Elsevier Science Inc. KEY WORDS
Aqueductal plasty, endoscopic, tectal glioma, third ventriculostomy.
eoplasms of the tectum are a potential cause of hydrocephalus [7,8,13,15,19,26]. Potential treatment options include shunt placement, third ventriculostomy, and aqueductal plasty [17,21,22].
N
Address reprint requests to: Dr Timothy M. George, P.O. Box 3272, Duke University Medical Center, Division of Neurosurgery, Durham, NC 27705. Received XX, 2002; accepted XX, 2002. 0090-3019/03/$–see front matter doi:10.1016/S0090-3019(02)00942-4
Case Presentation A 12-year-old patient presented with hydrocephalus, headaches, and blurry vision because of aqueductal compression from a tectal tumor (Figure 1). She underwent a third ventriculostomy with resolution of her symptoms. A follow-up magnetic resonance imaging (MRI) scan 2 weeks after the procedure revealed decreased ventricular size with flow through the third ventriculostomy (Figure 2). Five months after the procedure, the patient had gradual recurrence of her symptoms. A head computed tomography (CT) revealed increased ventricular size (Figure 3A). Subsequently she underwent a repeat third ventriculostomy as previously described [29]. Utilizing a 1.2-mm semi-rigid neuroen© 2003 by Elsevier Science Inc. 360 Park Avenue South, New York, NY 10010 –1710
Successful Aqueductal Plasty and Stenting
Surg Neurol 2003;59:58 – 62
59
past experience, this has led to poor patency of the third ventriculostomy. Because of these concerns, aqueductal plasty was performed at the same operation. The aqueduct was identified and noted to be occluded. This was opened with gentle saline irrigation and blunt dissection with the tip of the endoscope, after which the fourth ventricle was entered. A PS Medical cathether with side slits was placed as a stent from the lateral ventricles to the fourth ventricle (Figure 3B-D, 4). The catheter was attached to a ventricular reservoir that was attached to the skull to hold it in place. The other reason for using the reservoir was to establish percutaneous access to the ventricular system should emergency decompression be needed. Postoperatively, the patient did well and was discharged home on postoperative day one. At 1-year followup, she was doing well with no evidence of hydrocephalus.
1
Sagittal T1-weighted MRI scan immediately after third ventriculostomy. Note the ventriculomegaly.
doscope, the previous third ventriculostomy site was identified. This had healed over completely. A 1-cm opening was made in the floor of the third ventricle as previously described [29]. In cases of successful third ventriculostomy we have noted that the intracranial pressure decreases by about one third. This did not happen in our patient. In our
2
Axial MRI scan reveals decreased ventricular size after third ventriculostomy.
Discussion Dandy was the first to report aqueduct reconstruction. The mortality was significant with open procedures and therefore this was largely abandoned [22]. The preferred method of treatment for patients with hydrocephalus resulting from aqueductal stenosis became CSF shunts. However, shunts are associated with a high failure rate [1,2,20,24]. With improvements in neuroendoscopic equipment and techniques, third ventriculostomies have become a viable option for the management of hydrocephalus resulting from aqueductal compression [3,12,14,28,29]. The failure rate for third ventriculostomies approaches 30%, which is similar to that of shunts [3,22]. The most common cause of delayed failure is obstruction of the third ventriculostomy stoma because of proliferation of gliotic tissue [4]. This is also a problem with aqueductal plasty. It has been known since the time of Dandy that “strictures of the aqueduct of Sylvius recur after any attempt to restore the lumen” [6]. This high rate of reocclusion is the most common complication associated with this procedure. Most series report no significant morbidity or mortality associated with aqueductal plasty [17,11,25]. Attempts to keep the aqueduct open with stents have resulted in improved outcomes. Stenting with suboccipital craniotomies has a success rate of 59%, while the use of percutaneous techniques has resulted in a 79% success rate [22]. Currently, no significant morbidity has been reported with endoscopic aqueductal stent place-
60
Surg Neurol 2003;59:58 – 62
Bulsara et al
A: Axial CT scan of the brain reveals increased ventricular size. B-D: Immediate scan after secondary third ventriculostomy and aqueductal stenting. The stent courses through the lateral ventricles to the fourth via the aqueduct. It is attached at the skull to a ventricular reservoir.
3
ment. There appears to be a minimal risk of stent migration [27]. Only mild complications such as transient dysconjugate eye movements have been reported [7,9]. Traditionally, patients in whom endoscopic third ventriculostomy with or without aqueductal plasty fails undergo shunt placement. We report that aqueductal plasty may be a useful adjunct to third ventriculostomy if significant intracranial pressure decreases are not seen after third ventriculostomy. It may be a viable alternative to shunt placement. In our experience, aqueductal plasty for tectal tumors is not technically difficult. Our experience
suggests that the failure of intracranial pressure to decrease by about one third after third ventriculostomy may predict poor patency of the third ventriculostomy. These patients may benefit from aqueductal plasty and possible stenting. Congenital aqueductal stenosis and Dandy-Walker malformation, however, pose a more significant technical challenge. The aqueduct in these patients is often difficult to dilate, increasing the risk of hemorrhage and adverse stent passes into the brainstem. Long-term follow-up and future prospective studies are needed to determine the efficacy of secondary third ventriculostomies and aqueductal plasty with stenting.
Successful Aqueductal Plasty and Stenting
Cathether placed as a stent from the lateral ventricles to the fourth ventricle. Tectal glioma and narrowed aqueduct depicted.
4
REFERENCES 1. Abu-Dalu PD, Pode D, Hadani M, Sahar A. Colonic complications of ventriculoperitoneal shunts. Neurosurgery 1983;13:167–9. 2. Choudhury AR. Avoidable factors that contribute to the complications of ventriculoperitoneal shunt in childhood hydrocephalus. Childs Nerv Syst 1990;6: 346 –9. 3. Brockmeyer DAK, Abtin K, Carey L, Walker M. Endoscopic third ventriculostomy: an outcome analysis. Pediatr Neurosurg 1998:236 –40. 4. Cinalli G, Sainte-Rose C, Chumas P, et al. Failure of third ventriculostomy in the treatment of aqueductal stenosis in children. J Neurosurg 1999;90(3):448 –54. 5. Dalrymple SJ, Kelly PJ. Computer-assisted stereotactic third ventriculostomy in the management of noncommunicating hydrocephalus. Stereotact Funct Neurosurg 1992;59:105–10. 6. Dandy DE. An operative procedure for hydrocephalus. Bull Johns Hopkins Hosp 1922;33:189 –90. 7. Edwards MS, Hudgin RJ, Wilson CB, Levin VA, Wara WM. Pineal region tumors in children. J Neurosurg 1986;68:689 –97. 8. Flamm ES, Rovit RL, Kricheff II, Ransohoff J. Periaqueductal neoplasms and vascular malformations. NY State J Med 1972;72:2623–8. 9. Gaab MR, Schroeder HWS. Neuroendoscopic approach to intraventricular lesions. J Neurosurgery 1998;88:496 –505. 10. Goumnerova LC, Frim D. Treatment of hydrocephalus with third ventriculocisternostomy: outcome and CSF flow patterns. Pediatr Neurosurg 1997;32(6):1043–7. 11. Hamanda H, Hayashi N, Endo S, Kurimoto M, Hirashima Y, Takuku A. Endoscopic aqueductal plasty via the fourth ventricle through the cerebellar hemisphere under navigating system guidance— technical note. Neurologia Medico-Chirurigica 1999; 39:950 –2.
Surg Neurol 2003;59:58 – 62
61
12. Hopf NJ, Grunert P, Fries G, Resch K, Perneczky A. Endoscopic third ventriculostomy: outcome analysis of 100 consecutive procedures. Neurosurgery 1999; 44(4):795–803. 13. Pool LJ. Gliomas of the region of the brain stem. J Neurosurg 1968;29:164 –7. 14. Jones RF, Stening WA, Brydon M. Endoscopic third ventriculostomy. Neurosurgery 1990;26:86 –92. 15. Ho KL. Tumors of the cerebral aqueduct. Cancer 1982;49:154 –62. 16. Manwaring KH, Fritsch M. Endoscopic aqueductal stenting as an option for obstructive hydrocephalus [abstract]. Neurosurgery 1998;43:712–3. 17. Oka K, Yamamoto M, Ikeda K, Tomonaga M. Flexible endoneurosurgical therapy for aqueductal stenosis. Neurosurgery 1993;33(2):236 –42. 18. Oka K, Kin Y, Go Y, et al. Neuroendoscopic approach to tectal tumors: a consecutive series. J Neurosurg 1999;91(6):964 –70. 19. Pendl G, Vorkapic P, Koniyama M. Microsurgery of midbrain lesions. Neurosurgery 1990;26:641–8. 20. Piatt JH, Carlson C. A search for determinants of cerebrospinal fluid shunt survival: retrospective analysis of a 14-year institutional experience. Pediatr Neurosurg 1993;19:233–42. 21. Pollack IF, Pang D, Albright AL. The long-term outcome in children with late-onset aqueductal stenosis resulting from benign intrinsic tectal tumors. J Neurosurg 1994;80(4):681–8. 22. Schroeder HW, Gaab MR. Endoscopic aqueductoplasty. Neurosurgery 1999;45(3):508 –14. 23. Schwartz TH, Yoon SS, Cutruzzola FW, Goodman RR. Third ventriculostomy: post-operative ventricular size and outcome. Minim Invasive Neurosurg 1996;39: 122–9. 24. Sekhar LN, Moosey J, Guthkelch AN. Malfunctioning ventriculoperitoneal shunts: clinical and pathological features. J Neurosurg 1982;56:411–6. 25. Shin M, Morita A, Asano S, Ueki K, Kirino T. Neuroedoscopic aqueductal stent placement procedure for isolated fourth ventricular shunt placement. J Neurosurg 2000;92:1036 –9. 26. Steinbok P, Boyd MC. Periaqueductal tumor as a cause of late-onset aqueductal stenosis. Childs Nerv Syst 1987;3:170 –4. 27. Teo CMS, Cherny WB, Burson T. Surgical options in the management of the trapped fourth ventricle [abstract]. J Neurosurg 1996;84:356a. 28. Tuli S, Alshail E, Drake J. Third ventriculostomy versus cerebrospinal fluid shunt as a first procedure in pediatric hydrocephalus. Pediatr Neurosurg 1999;30: 11–5. 29. Wellons JC, Bagley CA, George TM. A simple and safe technique for endoscopic third ventriculocisternostomy. Pediatr Neurosurg 1999;30(4):219 –23.
COMMENTARY
Bulsara et al describe a case of a child with a tectal tumor treated initially with a third ventriculostomy, which was successful for a while. Subsequently, a second procedure was performed that included reopening the third ventriculostomy, doing an aqueductal plasty, and placing a stent. It is not clear