J Neurosurg 77:871-874, 1992
Syrinx shunt to posterior fossa cisterns (syringocisternostomy) for bypassing obstructions of upper cervical theca TIfOMAS H. MILtlORA'I, M.D., W,u:tr'.R D. JoItNSOm, M.D., AND JOHN L MILLER,M.D.
Department of Neurosu~ge*3', State University of New York Health Science Center at Brooklyn, and Kings Cotmly ttospital Center, BrookO'n, New York v- Syrinx shunts to the spinal subarachnoid space are likely to fail if the cerebrospinal fluid pathways rostral to the syrinx are blocked. To bypass obstructions al or below the level of the foramen magnum, a technique was developed for shunting the syrinx to the posterior fossa cisterns~ termed "syringocisternostomy." Syrinxes were shunted to the cisterna magna in two patients wilh spinal arachnoiditis and to the cerebellopontine angle cistern in four patients with Chiari 1 malformations. There was symptomatic improvement and collapse of the syrinx in each case, with no complications or recurrences over a follow-up interval of 14 to 27 months (average 20.3 months). The surgical technique and results of treatment are described. K~:v WoRos ' Chiari malformation surgical technique
HE treatment of syringomyelia by placement of a shunt to the spinal subarachnoid space, 17"~9 peritoneal cavity, ~'s'' ,.,4 or pleural cavity :'-'~ has enjoyed increasing popularity in recent years. Shunting can be performed as a primary treatment or when direct operations such as posterior fossa decompression for Chiari malformations fail to achieve symptomatic relief. Shunts to the spinal subarachnoid space are the simplest to implant but are not suitable when the cerebrospina[ fluid (CSF) pathways are obstructed rostral to the level of the syrinx. To bypass obstructions at or below the level of the foramen magnum, a technique was developed for shunting syrinxes to the posterior fossa cisterns, termed "syringocisternostomy." The procedure is less complicated than extraspinal shunting and has the potential advantage of requiring fewer revisions.
T
Clinical Material and Methods
Patient Population Six patients underwent posterior fossa shunting for syringomyelia (Table 1). The etiological factors included Chiari 1 malformation (four cases), trauma (one case), and extramedullary compression by a chronically herniated cervical disc (one case). Symptoms were precipitated by trauma in at least one patient with a Chiari I malformation. In five of the six patients, there were J. Neurosurg. / Volume 77/December, 1992
spinal arachnoiditis
syrinx
shunt
varying degrees of weakness and spasticity of the extremities. Additional findings in the patients included neck or back pain, paresthesias, hypalgesia, dissociated sensory loss, muscular atrophy, hyperreflexia, clonus, impaired position sense, urinary incontinence, BrownS6quard syndrome, and torticollis. Symptoms were progressive in four of the six patients. In one patient with posttraumatic syringomyelia and in one with a chronically herniated cervical disc who failed to improve following anterior discectomy, adhesions were encountered in the upper cervical theca that prohibited the placement of a spinal subarachnoid shunt so the syrinxes were diverted to the cisterna magna. Syrinxes occurring with Chiari malformations were shunted to the cerebellopontine angle cistern. Cerebellopontine angle shunting was performed as a primary procedure in three patients and as a secondary procedure in one patient who failed to improve following posterior fossa decompression and duraplasty. All patients in this series were examined by magnetic resonance (MR) imaging in the immediate postoperative period and at regular intervals of 6 to i2 months thereafter.
Operative Technique Operations were performed via a small laminectomy over the rostral end of the syrinx. The dura was opened 871
T. H. Milhorat, W. D. Johnson, and J. 1. Miller TABLE 1
('/i;~ica[ characteri.slics and ol(tc(,~;e in si.~ ptllit'HL~ l~'/l() ltlldl'l'n'('lt[ [}(~lurfol fOg~(l ~/Iltlllitlt~ (S)'I'iI1J,'O('i.XI['rlIO~'IoIH.I'J* .
-
Case Sex, Age No. (yrs)
;
....
Diagnosis
2
.
.....
Preoperative Findings
. . . .
Shunt
22
•
22Z;.:~277"Z
Postoperati',c Results
severe paraparesis (2/5), T-2 sensor5' level, S-CM mild paraparesis (4/5), walks without help, continent of urine, normal sensaincontinent of urine, confined to wheellion, syrinx collapsed chair, no change in syrinx size or symptoms after C4-5 diseectomy severe quadriparesis (2/5 UE & LE), conti- S-CM moderate quadriparcsis (3/5 LE, 4/5 nent of urine, confined to wheelchair UE). continent of urine, walks with help, syrinx not visualized
1
M. 57 herniated C4-5 disc, C5-T1 syrinx, spinal arachnoiditis
2
M, 48 C3-6 spondylosis, lraamatic laminectomy, spinal arachnoiditis, C1-6 syrinx F, 21 Chiari I malformation, mild paraparesis (4/5), torticollis, decreased S-CPA symptoms resolved, neurologically intact. C2-TI syrinx position sense & hyperreflexia in LE, no syrinx collapsed change in syrinx size or symptoms after posterior fossa decompression F. 34 Chiari l malformation, mild paraparesis (4/5), dissociated senso~ S-CPA symptoms resolved, neurologically intact, C2-6 syrinx loss, decreased position sense & hypersyrinx not visualized reflexia in LE F. 22 Chiari 1 malformation. It hemiparesis (3/5), dissociated sensory S-CPA symptoms resolved, neurologically intact C4-T9 syrinx loss, hypermflexia & clonus in LE excepl for decreased sweating on It side of body, syrinx not visualized F, 20 Chiari I malformalion, pain & numbness in It arm after motorS-CPA symptoms resolved, neurologically intact, C2-T2 syrinx vehicle accident syrinx collapsed
3
4
Follow-Up Period 27 mos
22 raps
26 raps
19 raps 14 mos 14 raps
* Abbreviations: UE = upper extremities; LE = lower extremities; S-CM = syrinx shunt to cisterna magna; S-CPA = syrinx shunt to cerebellopontine angle cistern,
a n d the syrinx was localized by ultrasonography. T h e u p p e r e n d o f the syrinx was p u n c t u r e d t h r o u g h its t h i n n e s t visible area or t h r o u g h the posterior longitudinal sulcus with a No. 20 spinal needle. O n c e a good flow o f fluid was established, the needle was replaced
with a P u d e n z v e n t r i c u l a r c a t h e t e r t h a t was t h r e a d e d caudally for o n e to two vertebral levels. T h e distal e n d of the catheter was passed extradurally or above the laminal arches to the f o r a m e n m a g n u m . A b u r r hole was m a d e in the occiput to o n e side o f the midline, just a b o v e the rim o f t h e f o r a m e n magn u m . T h e d u r a was o p e n e d a n d the a r a c h n o i d was p u n c t u r e d with a No, 11 blade. A silicone catheter with multiple holes at its distal e n d was i n t r o d u c e d into the cisterna magna. In patients with Chiari m a l f o r m a t i o n s , the catheter was passed a r o u n d the lateral surface o f
FIG. 1. Drawing illustrating a syrinx shunt to the cerebellopontine angle (CPA) cistern bypassing a Chiari I malformation. The upper end of the syrinx is cannulated through a one-level laminectomy and the catheter has been passed over the laminal arches to a suboccipital burr hole. The distal end of the catheter has been passed around the lateral surface of the cerebellar tonsil into the CPA cistern.
FIG. 2. Case 1. Left: Magnetic resonance (MR) image of the midsagittal cervical spine demonstrating a large syrinx that arises immediately caudal to the chronically herniated C4-5 disc. Right: Postoperative MR image, obtained 9 days after shunting to the cisterna magna, showing collapse of the syrinx. An MR image obtained 6 months after treatment was unchanged. Note the anterior discectomy at C4-5.
872
J. Nez~rosz~rg. / Volume 77/December, 1992
Syringocisternostomy to bypass hindbrain obstructions the cerebellar tonsil into the cerebellopontine angle cistern (Fig. 1). The distal and proximal limbs of the shunt were trimmed to an appropriate length and joined with a plastic connector that was secured to the dura with 4-0 neuralon sutures. Syrinxes were observed to deflate promptly at the time of surgery. Results Magnetic resonance images obtained in the immediate postoperative period demonstrated collapse or disappearance of the syrin~ in all six cases (Figs. 2 and 3). Follow-up MR imaging performed on an annual or biannual basis revealed no recurrences over an interval of 14 to 27 months. Symptoms improved in two patients and completely resolved in four. The results of treatment are summarized in Table 1. Discussion The surgical treatment of a syrinx occurring in association with a lesion at the level of the foramen magnum has not been standardized. The traditional approach is posterior fossa decompression, which can include a variety of additional steps such as lysis of adhesions, amputation of the cerebellar tonsils, plugging of the obex, shunting of the fourth ventricle, and duraplasty._,-7.9.,o.~2. Js.J6 However, in the most favorable series, posterior fossa decompression leads to a significant improvement in symptoms and a reduction in syrinx size in only 50% of patients. 15 Some neurosurgeons have reported that the procedure rarely provides good results and that the risks attendant to posterior fossa operations are probably not justified. 5
The failure of direct operations to provide safe and consistent results in the treatment of syringomyelia has led to the use of a wide array of syrinx shunting procedures, including syringosubarachnoid, ~7~ sytingoperitoneal, '-~ ' "~4 syringopleural,~5':~ and lumboperitoneal shunts. ~ A requirement of syringosubarachnoid shunting is that the distal subarachnoid spaces, including the upper cervical theca, provide a competent pathway for CSF drainage. Examples of obstructions that may contraindicate the use of a spinal subarachnoid shunt are Chiari malformations, basilar impression, and spinal arachnoiditis. To bypass obstructions at or below the level of the foramen magnum, the syringocisternostomy technique was developed for shunting the syrinx to the posterior fossa cisterns. When the cisterna magna was not available, the syrinx was diverted into the cerebellopontine angle cistern. The technique of syringocisternostomy is similar in some respects to the Torkildsen shunt (ventriculocisternostomy), which is effective in bypassing intracranial blocks provided that the distal subarachnoid spaces are patent. ~s In this series, the syrinx was diverted to the cisterna magna in two patients with spinal arachnoiditis and the cerebellopontine angle cistern in four patients with Chiati malformations. There was symptomatic improvement and collapse of the syrinx in each case, with no complications or recurrences over a follow-up interval of 14 to 27 months. As with other internal shunts, syringocisternostomy has the potential for requiting fewer revisions than shunting to the body cavities, but more experience will be necessary before the procedure can be recommended for widespread use. References
FIG. 3. Case 5. Left: Magnetic resonance (MR) image of the midsagittal cervical spine demonstrating a syrinx in association with a Chiari I malformation. Right: Postoperative MR image, obtained 3 weeks after shunting to the cerebellopontine angle cistern showing no visualization of the syrinx. The filling void represents the proximal end of the shunt. An MR image obtained at 12 months after treatment was unchanged.
J. Neurosurg. / Volume 77/December, 1992
1. Barbaro NM, Wilson CB, Gutin PH, et al: Surgical treatment ofsyringomyelia. Favorable results with syringoperitoneal shunting. J Neurosurg 61:531-538, 1984 2. Batzdorf U: Chiari I malformation with syringomyelia. Evaluation of surgical therapy by magnetic resonance imaging. J Neurosurg 68:726-730, 1988 3. Bertrand G: Dynamic factors in the evolution of syringomyelia and syringobulbia. Clin Neurosurg 20:322-333, 1973 4. Cahan LD, Bentson JR: Considerations in the diagnosis and treatment of syringomyelia and the Chiari malformation. J Neurosurg 57:24-31, 1982 5. Gamache FW Jr, Ducker TB: Syringomyelia: a neurological and surgical spectrum. J Spinal Disord 3:293-298, 1990 6. Garcia-Uria J, Leunda G, Carrillo R, el al: Syringomyelia: long-term results after posterior fossa decompression. J Neurosurg 54:380-383, 1981 7. Gardner WJ, Goodall RJ: The surgical treatment of Arnold-Chiari malformation in adults. An explanation of its mechanism and importance of encephalography in diagnosis. J Neurosurg 7:199-206, 1950 8. Lesoin F, Petit H, Thomas CE Ill, et al: Use of the syringoperitoneal shunt in the treatment of syringomyelia. Surg Neurol 25:131-136, 1986 9. Levy WJ, Mason L, Hahn JF: Chiari malformation presenting in adults: a surgical experience in 127 cases. 873
T. H. Milhorat, W. D. Johnson, and J. I. Miller Neurosurgery 12:377-390, 1983 10. Logue V, Edwards MR: Syringomyelia and its surgical treatment - - an analysis of 75 patients. J Neurol Neurosurg Psychiatry 44:273-284, I981 11. Matsumoto T, Symon L: Surgical management of syringomyelia - - current results. Surg Neurnl 32:258-265, 1989 12. McLean DR, Miller JDR, Allen PBR, et al: Posttraumatic syringomyelia. J Neurosurg 39:485-492, 1973 13. Park TS, Cail WS, Broaddus WC, et al: Lumboperitoneal shunt combined with myelotomy for treatment of syringohydromyelia. J Neurosurg 70:721-727, 1989 14. Phillips TW, Kindt GW: Syringoperitoneal shunt for syringomyelia: a preliminary report. Surg Neurol 16: 462-466, 1981 15. Pillay PK, Awad IA, Little JR, et al: Symptomatic Chiari malformation in adults: a new classification based on magnetic resonance imaging with clinical and prognostic significance. Neurosurgery 28:639-645, 199l 16. Rhoton AL Jr: Microsurgery of Arnold-Chiari malformation in adults with and without hydromyelia. J Neurosurg 45:473-483, 1976
874
17. Tator CH, Megura K, Rowed DW: Favorable results with syringosubarachnoid shunts for treatment of syringomyelia. J Neurosurg 56:517-523, 1982 18. Torkildsen A: New palliative operation in cases of inoperable occlusion of sylvian aqueduct. Acta Chir Stand 82:117-123, 1939 19. Vaquero J, Martinez R, Salazar J, et al: Syringosubarachnoid shunt for treatment of syringomyelia. Aeta Neurochit 84:105-109, 1987 20. Wisoff JH, Epstein F: Management of hydromyelia. Neurosurgery 25:562-571, 1989
Manuscript received February 19, 1992. Accepted in final form May 14, 1992. This work was supported by the InternationalNeuroscience Foundation and the Harry Arthur Kaplan Neurosurgery Research Fund. Address reprint requests to: Thomas H. Milhorat, M.D., Department of Neurosurgery, State University of New York Health Science Center at Brooklyn, 450 Clarkson Avenue, Box 1189, Brooklyn, New York 11203-2098.
J. Neurosurg. / Volume 77/December, 1992
Syrinx shunt to posterior fossa cisterns (syringocisternostomy) for bypassing obstructions of upper cervical theca TIfOMAS H. MILtlORA'I, M.D., W,u:tr'.R D. JoItNSOm, M.D., AND JOHN L MILLER,M.D.
Department of Neurosu~ge*3', State University of New York Health Science Center at Brooklyn, and Kings Cotmly ttospital Center, BrookO'n, New York v- Syrinx shunts to the spinal subarachnoid space are likely to fail if the cerebrospinal fluid pathways rostral to the syrinx are blocked. To bypass obstructions al or below the level of the foramen magnum, a technique was developed for shunting the syrinx to the posterior fossa cisterns~ termed "syringocisternostomy." Syrinxes were shunted to the cisterna magna in two patients wilh spinal arachnoiditis and to the cerebellopontine angle cistern in four patients with Chiari 1 malformations. There was symptomatic improvement and collapse of the syrinx in each case, with no complications or recurrences over a follow-up interval of 14 to 27 months (average 20.3 months). The surgical technique and results of treatment are described. K~:v WoRos ' Chiari malformation surgical technique
HE treatment of syringomyelia by placement of a shunt to the spinal subarachnoid space, 17"~9 peritoneal cavity, ~'s'' ,.,4 or pleural cavity :'-'~ has enjoyed increasing popularity in recent years. Shunting can be performed as a primary treatment or when direct operations such as posterior fossa decompression for Chiari malformations fail to achieve symptomatic relief. Shunts to the spinal subarachnoid space are the simplest to implant but are not suitable when the cerebrospina[ fluid (CSF) pathways are obstructed rostral to the level of the syrinx. To bypass obstructions at or below the level of the foramen magnum, a technique was developed for shunting syrinxes to the posterior fossa cisterns, termed "syringocisternostomy." The procedure is less complicated than extraspinal shunting and has the potential advantage of requiring fewer revisions.
T
Clinical Material and Methods
Patient Population Six patients underwent posterior fossa shunting for syringomyelia (Table 1). The etiological factors included Chiari 1 malformation (four cases), trauma (one case), and extramedullary compression by a chronically herniated cervical disc (one case). Symptoms were precipitated by trauma in at least one patient with a Chiari I malformation. In five of the six patients, there were J. Neurosurg. / Volume 77/December, 1992
spinal arachnoiditis
syrinx
shunt
varying degrees of weakness and spasticity of the extremities. Additional findings in the patients included neck or back pain, paresthesias, hypalgesia, dissociated sensory loss, muscular atrophy, hyperreflexia, clonus, impaired position sense, urinary incontinence, BrownS6quard syndrome, and torticollis. Symptoms were progressive in four of the six patients. In one patient with posttraumatic syringomyelia and in one with a chronically herniated cervical disc who failed to improve following anterior discectomy, adhesions were encountered in the upper cervical theca that prohibited the placement of a spinal subarachnoid shunt so the syrinxes were diverted to the cisterna magna. Syrinxes occurring with Chiari malformations were shunted to the cerebellopontine angle cistern. Cerebellopontine angle shunting was performed as a primary procedure in three patients and as a secondary procedure in one patient who failed to improve following posterior fossa decompression and duraplasty. All patients in this series were examined by magnetic resonance (MR) imaging in the immediate postoperative period and at regular intervals of 6 to i2 months thereafter.
Operative Technique Operations were performed via a small laminectomy over the rostral end of the syrinx. The dura was opened 871
T. H. Milhorat, W. D. Johnson, and J. 1. Miller TABLE 1
('/i;~ica[ characteri.slics and ol(tc(,~;e in si.~ ptllit'HL~ l~'/l() ltlldl'l'n'('lt[ [}(~lurfol fOg~(l ~/Iltlllitlt~ (S)'I'iI1J,'O('i.XI['rlIO~'IoIH.I'J* .
-
Case Sex, Age No. (yrs)
;
....
Diagnosis
2
.
.....
Preoperative Findings
. . . .
Shunt
22
•
22Z;.:~277"Z
Postoperati',c Results
severe paraparesis (2/5), T-2 sensor5' level, S-CM mild paraparesis (4/5), walks without help, continent of urine, normal sensaincontinent of urine, confined to wheellion, syrinx collapsed chair, no change in syrinx size or symptoms after C4-5 diseectomy severe quadriparesis (2/5 UE & LE), conti- S-CM moderate quadriparcsis (3/5 LE, 4/5 nent of urine, confined to wheelchair UE). continent of urine, walks with help, syrinx not visualized
1
M. 57 herniated C4-5 disc, C5-T1 syrinx, spinal arachnoiditis
2
M, 48 C3-6 spondylosis, lraamatic laminectomy, spinal arachnoiditis, C1-6 syrinx F, 21 Chiari I malformation, mild paraparesis (4/5), torticollis, decreased S-CPA symptoms resolved, neurologically intact. C2-TI syrinx position sense & hyperreflexia in LE, no syrinx collapsed change in syrinx size or symptoms after posterior fossa decompression F. 34 Chiari l malformation, mild paraparesis (4/5), dissociated senso~ S-CPA symptoms resolved, neurologically intact, C2-6 syrinx loss, decreased position sense & hypersyrinx not visualized reflexia in LE F. 22 Chiari 1 malformation. It hemiparesis (3/5), dissociated sensory S-CPA symptoms resolved, neurologically intact C4-T9 syrinx loss, hypermflexia & clonus in LE excepl for decreased sweating on It side of body, syrinx not visualized F, 20 Chiari I malformalion, pain & numbness in It arm after motorS-CPA symptoms resolved, neurologically intact, C2-T2 syrinx vehicle accident syrinx collapsed
3
4
Follow-Up Period 27 mos
22 raps
26 raps
19 raps 14 mos 14 raps
* Abbreviations: UE = upper extremities; LE = lower extremities; S-CM = syrinx shunt to cisterna magna; S-CPA = syrinx shunt to cerebellopontine angle cistern,
a n d the syrinx was localized by ultrasonography. T h e u p p e r e n d o f the syrinx was p u n c t u r e d t h r o u g h its t h i n n e s t visible area or t h r o u g h the posterior longitudinal sulcus with a No. 20 spinal needle. O n c e a good flow o f fluid was established, the needle was replaced
with a P u d e n z v e n t r i c u l a r c a t h e t e r t h a t was t h r e a d e d caudally for o n e to two vertebral levels. T h e distal e n d of the catheter was passed extradurally or above the laminal arches to the f o r a m e n m a g n u m . A b u r r hole was m a d e in the occiput to o n e side o f the midline, just a b o v e the rim o f t h e f o r a m e n magn u m . T h e d u r a was o p e n e d a n d the a r a c h n o i d was p u n c t u r e d with a No, 11 blade. A silicone catheter with multiple holes at its distal e n d was i n t r o d u c e d into the cisterna magna. In patients with Chiari m a l f o r m a t i o n s , the catheter was passed a r o u n d the lateral surface o f
FIG. 1. Drawing illustrating a syrinx shunt to the cerebellopontine angle (CPA) cistern bypassing a Chiari I malformation. The upper end of the syrinx is cannulated through a one-level laminectomy and the catheter has been passed over the laminal arches to a suboccipital burr hole. The distal end of the catheter has been passed around the lateral surface of the cerebellar tonsil into the CPA cistern.
FIG. 2. Case 1. Left: Magnetic resonance (MR) image of the midsagittal cervical spine demonstrating a large syrinx that arises immediately caudal to the chronically herniated C4-5 disc. Right: Postoperative MR image, obtained 9 days after shunting to the cisterna magna, showing collapse of the syrinx. An MR image obtained 6 months after treatment was unchanged. Note the anterior discectomy at C4-5.
872
J. Nez~rosz~rg. / Volume 77/December, 1992
Syringocisternostomy to bypass hindbrain obstructions the cerebellar tonsil into the cerebellopontine angle cistern (Fig. 1). The distal and proximal limbs of the shunt were trimmed to an appropriate length and joined with a plastic connector that was secured to the dura with 4-0 neuralon sutures. Syrinxes were observed to deflate promptly at the time of surgery. Results Magnetic resonance images obtained in the immediate postoperative period demonstrated collapse or disappearance of the syrin~ in all six cases (Figs. 2 and 3). Follow-up MR imaging performed on an annual or biannual basis revealed no recurrences over an interval of 14 to 27 months. Symptoms improved in two patients and completely resolved in four. The results of treatment are summarized in Table 1. Discussion The surgical treatment of a syrinx occurring in association with a lesion at the level of the foramen magnum has not been standardized. The traditional approach is posterior fossa decompression, which can include a variety of additional steps such as lysis of adhesions, amputation of the cerebellar tonsils, plugging of the obex, shunting of the fourth ventricle, and duraplasty._,-7.9.,o.~2. Js.J6 However, in the most favorable series, posterior fossa decompression leads to a significant improvement in symptoms and a reduction in syrinx size in only 50% of patients. 15 Some neurosurgeons have reported that the procedure rarely provides good results and that the risks attendant to posterior fossa operations are probably not justified. 5
The failure of direct operations to provide safe and consistent results in the treatment of syringomyelia has led to the use of a wide array of syrinx shunting procedures, including syringosubarachnoid, ~7~ sytingoperitoneal, '-~ ' "~4 syringopleural,~5':~ and lumboperitoneal shunts. ~ A requirement of syringosubarachnoid shunting is that the distal subarachnoid spaces, including the upper cervical theca, provide a competent pathway for CSF drainage. Examples of obstructions that may contraindicate the use of a spinal subarachnoid shunt are Chiari malformations, basilar impression, and spinal arachnoiditis. To bypass obstructions at or below the level of the foramen magnum, the syringocisternostomy technique was developed for shunting the syrinx to the posterior fossa cisterns. When the cisterna magna was not available, the syrinx was diverted into the cerebellopontine angle cistern. The technique of syringocisternostomy is similar in some respects to the Torkildsen shunt (ventriculocisternostomy), which is effective in bypassing intracranial blocks provided that the distal subarachnoid spaces are patent. ~s In this series, the syrinx was diverted to the cisterna magna in two patients with spinal arachnoiditis and the cerebellopontine angle cistern in four patients with Chiati malformations. There was symptomatic improvement and collapse of the syrinx in each case, with no complications or recurrences over a follow-up interval of 14 to 27 months. As with other internal shunts, syringocisternostomy has the potential for requiting fewer revisions than shunting to the body cavities, but more experience will be necessary before the procedure can be recommended for widespread use. References
FIG. 3. Case 5. Left: Magnetic resonance (MR) image of the midsagittal cervical spine demonstrating a syrinx in association with a Chiari I malformation. Right: Postoperative MR image, obtained 3 weeks after shunting to the cerebellopontine angle cistern showing no visualization of the syrinx. The filling void represents the proximal end of the shunt. An MR image obtained at 12 months after treatment was unchanged.
J. Neurosurg. / Volume 77/December, 1992
1. Barbaro NM, Wilson CB, Gutin PH, et al: Surgical treatment ofsyringomyelia. Favorable results with syringoperitoneal shunting. J Neurosurg 61:531-538, 1984 2. Batzdorf U: Chiari I malformation with syringomyelia. Evaluation of surgical therapy by magnetic resonance imaging. J Neurosurg 68:726-730, 1988 3. Bertrand G: Dynamic factors in the evolution of syringomyelia and syringobulbia. Clin Neurosurg 20:322-333, 1973 4. Cahan LD, Bentson JR: Considerations in the diagnosis and treatment of syringomyelia and the Chiari malformation. J Neurosurg 57:24-31, 1982 5. Gamache FW Jr, Ducker TB: Syringomyelia: a neurological and surgical spectrum. J Spinal Disord 3:293-298, 1990 6. Garcia-Uria J, Leunda G, Carrillo R, el al: Syringomyelia: long-term results after posterior fossa decompression. J Neurosurg 54:380-383, 1981 7. Gardner WJ, Goodall RJ: The surgical treatment of Arnold-Chiari malformation in adults. An explanation of its mechanism and importance of encephalography in diagnosis. J Neurosurg 7:199-206, 1950 8. Lesoin F, Petit H, Thomas CE Ill, et al: Use of the syringoperitoneal shunt in the treatment of syringomyelia. Surg Neurol 25:131-136, 1986 9. Levy WJ, Mason L, Hahn JF: Chiari malformation presenting in adults: a surgical experience in 127 cases. 873
T. H. Milhorat, W. D. Johnson, and J. I. Miller Neurosurgery 12:377-390, 1983 10. Logue V, Edwards MR: Syringomyelia and its surgical treatment - - an analysis of 75 patients. J Neurol Neurosurg Psychiatry 44:273-284, I981 11. Matsumoto T, Symon L: Surgical management of syringomyelia - - current results. Surg Neurnl 32:258-265, 1989 12. McLean DR, Miller JDR, Allen PBR, et al: Posttraumatic syringomyelia. J Neurosurg 39:485-492, 1973 13. Park TS, Cail WS, Broaddus WC, et al: Lumboperitoneal shunt combined with myelotomy for treatment of syringohydromyelia. J Neurosurg 70:721-727, 1989 14. Phillips TW, Kindt GW: Syringoperitoneal shunt for syringomyelia: a preliminary report. Surg Neurol 16: 462-466, 1981 15. Pillay PK, Awad IA, Little JR, et al: Symptomatic Chiari malformation in adults: a new classification based on magnetic resonance imaging with clinical and prognostic significance. Neurosurgery 28:639-645, 199l 16. Rhoton AL Jr: Microsurgery of Arnold-Chiari malformation in adults with and without hydromyelia. J Neurosurg 45:473-483, 1976
874
17. Tator CH, Megura K, Rowed DW: Favorable results with syringosubarachnoid shunts for treatment of syringomyelia. J Neurosurg 56:517-523, 1982 18. Torkildsen A: New palliative operation in cases of inoperable occlusion of sylvian aqueduct. Acta Chir Stand 82:117-123, 1939 19. Vaquero J, Martinez R, Salazar J, et al: Syringosubarachnoid shunt for treatment of syringomyelia. Aeta Neurochit 84:105-109, 1987 20. Wisoff JH, Epstein F: Management of hydromyelia. Neurosurgery 25:562-571, 1989
Manuscript received February 19, 1992. Accepted in final form May 14, 1992. This work was supported by the InternationalNeuroscience Foundation and the Harry Arthur Kaplan Neurosurgery Research Fund. Address reprint requests to: Thomas H. Milhorat, M.D., Department of Neurosurgery, State University of New York Health Science Center at Brooklyn, 450 Clarkson Avenue, Box 1189, Brooklyn, New York 11203-2098.
J. Neurosurg. / Volume 77/December, 1992
