Letters to Editor
support clip and groove of the base ring are in line, the ideal fulcrum is lost and force can be applied along the lead. Our report describes lead migration and the technical nuances associated with positioning of the Stimloc cap to the burr hole cover during DBS surgery.
Zion Zibly, Mayur Sharma, Andrew Shaw, Esmiralda Yeremeyeva, Milind Deogaonkar, Ali Rezai Department of Neurosurgery, Center of Neuromodulation, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA E‑mail: [email protected]
References Figure 4: Merged before and after cap placement fluoroscopy. Placement of the cap caused lateral shift directly below the Stimloc device with subsequent dorsal shift in lead placement (enlarged with contacts highlighted)
1.
Alex Mohit A, Samii A, Slimp JC, Grady MS, Goodkin R. Mechanical failure of the electrode wire in deep brain stimulation. Parkinsonism Related Disord 2004;10:153‑6. 2. Chan DT, Zhu XL, Yeung JH, Mok VC, Wong E, Lau C, et al. Complications of deep brain stimulation: A collective review. Asian J Surg 2009;32:258‑63. 3. Ray CD. Burr‑hole ring‑cap and electrode anchoring device. Technical note. J Neurosurg 1981;55:1004‑6. 4. Sharma M, Rhiew R, Deogaonkar M, Rezai A, Boulis N. Accuracy and precision of targeting using frameless stereotactic system in deep brain stimulator implantation surgery. Neurol India 2014;62:503‑9. Access this article online
a
b
Figure 5: (a) Support clip positioned in line with the groove of the base ring. (b) Ideal positioning of the support clip in relation to the base ring
through the Leksell cross hairs targeting system adapter was performed to confirm the position of electrode. The support clip (“pacman”) was positioned onto the base ring of the Stimloc system to secure the lead and fluoroscopy repeated. The lead was then carefully released from the robotic drive and no movement of the electrode was confirmed [Figure 2]. The cap was placed and fluoroscopy was repeated [Figure 3]. Before and after cap fluoroscopy images were merged [Figure 4] and lead was noted to have migrated approximately 2 mm dorsal from the target. The cap was removed and the lead was confirmed to revert back to the same starting depth position. The locking slot of the support clip was oriented parallel with the groove in the burr hole base ring. Since the lead wire appeared to angle upwards with placement of the cap, the team suggested a more perpendicular placement of the locking slot of the support clip relative to the groove in the base ring. The support clip was repositioned perpendicular to the groove and fluoroscopy confirmed that the lead was at the original desired depth. The ideal orientation of the support clip is to position the static side of the V‑shaped opening at approximately 90 degrees to the exit slot (Medtronic Stimloc Technical Manual, Medtronic Inc, 2007) [Figure 5]. When the 704
Quick Response Code:
Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.149441
Received: 11-07-2014 Review completed: 09-12-2014 Accepted: 16-12-2014
Non‑terminal cervical myelocystocele: Unusual cause of spastic quadriparesis in an adult Sir, Terminal and non‑terminal variants of myelocystocele are divided on anatomic location and postulated hypothesis of origin. [1,2] Former is a disorder of retrogressive differentiation (secondary neurulation) compared to limited dorsal myeloschisis (primary neurulation) in latter.[1,3] To the best of author’s knowledge, till date only 38 cases of non‑terminal myelocystocele (NTM or equivalent pathology) [1,3‑14] have been published in literature [Table 1] with most common age of presentation being neonates and infants. Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
Yes (USG)
Yes (USG and MRI) No
4 year/F
6 year/F
3 days/F
5 days/F
Khandelwal et al. (2011)[8]
Chandra et al. (2011)[6] Carmody et al. (2012)[5] Gressot et al. (2014)[7] Present study (2014)
No
Complete
Complete
Cervico‑thoracic Cervical
Abortive
Complete
Abortive
Abortive
Thoracic
Cervical
Thoracic
Cervical 3 Upper thoracic 1 Lower thoracic 1 Thoraco‑lumbar 1 Cervical
Cervical
ACM II Hydromyelia
ACM II Low lying cord Arrested HCP ACM II Syringomyelia
None
SCM I SCM II HCP Bifid fatty filum Dermal coccygeal sinus Syringomyelia
ACM II HCP
Resection, detethering, foramen magnum decompression and lax duraplasty Resection+Detethering – 2 Resection only ‑ 3
Resection, detethering
Resection, detethering and excision of tumor VP∆ shunt+resection of MCC# ‑ 3 MC° resection+detethering – 3 Extradural excision of MC ‑ 2
Spastic quadriparesis Incontinence
Normal
Normal
Normal
Paraparesis
Normal
NA
Normal
NA
Normal (1 year)
Normal (7 months)
Normal – 2 B/l VUR, increased HCP and increased hydromyelia – 2 (17 months)
Normal (2 years)
Normal except positive babinski sign in right foot (18 mo) Retethering with neurological deterioration – 5 Normal – 3 (31 months) Normal (6 mo)
Outcome (follow up)
Resection, detethering
Resection, detethering
Resection, detethering
Reduced spasticity Improved power (6 mo)
Normal (3 mo)
Normal (6 mo)
Resection, detethering followed by Normal (immediate post‑op); VP shunt shunt done for respiratory distress Repair of MCC Same as before at discharge. Excision of 2 level SCM I Further follow up NA Excision of SCM II VP shunt Excision of dermal sinus and filum Resection, Detethering Normal (Follow up NA)
Resection, intra‑dural exploration and detethering
Resection, detethering
Paraplegia+ Resection+Detethering ‑ 9 Incontinence – 1 Normal – 8
Normal with respiratory distress Normal
Normal
Normal
Normal
Neurological Surgery examination
‡
$
Variant - Based on Rossi et al. classification, αNA - Not available, *ACM II - Arnold‑chiari malformation type II, †HCP - Hydrocephalus, ∆VP - Ventriculo‑peritoneal, #MCC - Myelocystocele, ⁰MC - Meningocele, USG ‑ Ultrasonography, MRI - Magnetic resonance imaging, ∞VUR - Vesicoureteric reflex, §SCM - Split cord malformation, ^LDM - Limited dorsal myeloschisis
42 year/M
No
Infant/F
Ochiai et al. (2010)[11]
No
9 Infants NA (10 days to 3 months) 9F 2 mo/F Yes (USG and MRI) 6 patients No
Muthukumar et al. (2007)[1]
Klein et al. (2009)[9] Pang et al. (2010)[12]
Yes (USG) – 3 Cervical – 3 No – 3 Thoracic – 2 Lumbar ‑ 1
6 children (1 day to 6 years) 4 M/2 F
Rossi et al. (2006)[3]
Cervical – 1 Thoracic – 6 Lumbosacral ‑ 2
Complete
Cervical
None
Hydromyelia – 3 ACM II – 5 HCP – 5
Cerebellar heterotropia
Associated anomalies
ACM II – 3 HCP – 1 Hydromyelia – 2 Neurenteric cyst – 1 Filar lipoma – 1 Complete – 3 Aqueductal stenosis – 1 Abortive ‑ 6 ACM II – 1 Low lying conus medullaris – 2 SCM§ ‑ 1 Complete Syringomyelia Lipoma LDM^‑Saccular NA MCC (≈Complete)
Complete
Cervical
Yes (USG‡/ MRI) No
Bhargava et al. 1 day/M (1992)[4] Nishino et al. 2 days/F (1998)[10] Complete – 3 Abortive ‑ 3
Cervical – 7 Complete – 3 Cervico‑thoracic ‑ 1 Abortive ‑ 5
Complete
Variant$
NA α
Location Cervico‑thoracic
Prenatal diagnosis
No
Age/sex
Suneson et al. 21 mo/M (1979)14 Steinbok et al. 8 Infants (1991)[13] (1 day to 9 months)
Author (year)
Table 1: Summary of non‑terminal myelocystocele: Patient profile, surgical modality and outcome
Letters to Editor
705
Letters to Editor
We present a unique case of cervical NTM in a 42‑year‑old male who presented with progressive spastic ascending quadriparesis (power 4/5 below C6 myotome), decreased sensation (below C6 dermatome) for two years, and upper motor neuron type bowel and bladder dysfunction for eight months. Local examination revealed 5 × 4 × 3 cm midline non‑tender cystic saccular skin covered lesion with dysplastic skin in midline along with hypertrichosis and positive fluctuation test [Figure 1a]. Magnetic resonance imaging (MRI) of craniospinal axis revealed arrested hydrocephalus, mild type I Arnold‑Chiari malformation II [3] (ACM II) with cerebellar tissue pegging through foramen magnum, fused C6/7 and D1/2 vertebrae, spina bifida defect at C6‑C7 level, tenting of open‑book configuration spinal cord at C6‑C7 level with posteriorly tethered cystic dilation continuous with hydromyelic cavity, attached to dome of cystic meningocele lying below intact skin [Figure 1b‑d). Abnormal cerebrospinal fluid (CSF) flow dynamics are seen in dilated sub‑arachnoid space ventral to cord at the level of cord tethering along with syrinx cranially. Dorsally central canal is open and continuous with ependymal lined cyst tethered to dysplastic skin dorsally. Radiological diagnosis of NTM (Rossi type B) [3] was made. Intra‑operatively fused posterior elements of C6/7 with a midline spina bifida defect was seen with dural sac meningocele containing ependymal lined and extending intra‑spinally to invest on dorsal aspect of spinal cord and communicating with dilated central canal [Figure 2]. Complete excision of tethering band and intra‑spinal adhesiolysis was done to release cord adequately. Histopathological examination revealed microscopic nests of glial tissue along with adipose tissue in a fibro‑collagenous background confirming the diagnosis of myelocystocele [Figure 3]. Patient had a clinical improvement from neurological grade three to two post‑operatively (as classified by Pang et al.),[12] which remained stable till last follow up at six months. Interval MRI done after three months was suggestive of stable ventricular size, reduction of CSF space ventral to cord with improved flow dynamics and evidence of detethered spinal cord with non‑progression of syrinx and ACM II [Figure 4]. Myelocystocele is a rare variant of closed spinal dysraphism characterized by skin covered mass located posteriorly in midline, narrow spina bifida defect, cerebrospinal fluid cyst, expanded dural sheath with varying amounts of dorsal fat continuous with sub‑cutaneous fat.[15] Though no proven genetic basis exists, it has been associated with intrauterine exposure to retinoic acid, [16] loperamide [17] and hydantoin. [18] Developmental origin of NTM is hypothesized by limited dorsal myeloschisis leading to delayed 706
a
b
c
d
Figure 1: (a) Pre‑operative clinical photograph demonstrating midline cystic cervical lesion covered with dysplastic skin suggestive of non‑terminal myelocystocele (MCC). (b) Axial T2W magnetic resonance image (MRI) demonstrating “open‑book” configuration of cord with hydromyelic cavity continuing as myelocele (MYC) through spina‑bifida (SB) bony defect and investing on outer cystic cavity of dural meningocele (MC) below intact skin. (c) and (d) Saggital T2W MRI showing C6/7 and D1/2 block vertebrae (BV), mild chiari II malformation (ACM) features with cerebellar pegging through foramen magnum. Cord is tented dorsally to meningocele (MC) sac with resultant increased sub‑arachnoidal space along with abnormal cerebrospinal fluid flow dynamics ventrally creating flow voids (FV)
a
b
Figure 2: Intra‑operative photograph (a) demonstrating myelocele (MYC) sac tethered dorsally to meningocele (MC) sac and its relation to normal cord. (b) After detethering, small part of residual myelocele sac seen with thinned out distal cord (DC) and proximal cord (PC) owing to release of syringomyelic cavity communicating with myelocele
a
b
Figure 3: HPE findings – (a) Photomicrograph showing fibro‑collagenous tissue and fibro‑adipose tissue (H and E x100). (b) Photomicrograph shows small islands of glial tissue along with neuro‑melanin (arrow) admixed in a fibro‑collagenous background (H and E x100)
disjunction of ectoderm and neuro‑ectoderm in final stages of primary neurulation, thereby leaving small defect in midline.[1,3] Surrounding mesenchyme and ectodermal elements overgrow and cover this small defect, leaving on small part of dorsal cord tissue connected to skin in form of either well formed Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
Letters to Editor
Amol Raheja, Deepak Kumar Gupta, Aasma Nalwa1, Vaishali Suri1, Bhawani Shankar Sharma
b
Departments of Neurosurgery and Gamma Knife, and 1Pathology, All India Institute of Medical Sciences, New Delhi, India E‑mail: [email protected]
References
a
c
Figure 4: Follow up (a) ‑ saggital, (b) and (c) – axial magnetic resonance images after six months demonstrating completely untethered cord (UC) with remnant hydromyelic cavity (HC) and reduced ventral sub‑arachnoidal space along with no evidence of flow voids (NFV) attributing to laminar cerebrospinal fluid flow pattern after procedure. There is evidence of non‑progression of chiari II malformation compared to pre‑operative imaging
myelocystocele (complete variant, Rossi type B, myelocystocele, limited dorsal myeloschisis with saccular myelocystocele and myelocystocele consisting of a second ependymal lined cyst herniated inside a meningocele) or neuro‑fibro‑vascular band (abortive variant, Rossi type A, fibroneurovascular stalk, limited dorsal myeloschisis with stalk and cystic spinal dysraphism with neuro‑glial stalk) based on classification given by Rossi et al.,[3] Habibi et al.,[19] Pang et al.[12] and Salamao et al.,[20] respectively. Severity of symptoms is unrelated to location of lesion but probably increases with increasing age.[12] Surgical strategy aims at excision, intra‑dural exploration and complete detethering for optimal outcome, with poor neurological outcome associated when only extra‑dural excision is undertaken. [21] The index case ponders us to acknowledge that such lesions may remain asymptomatic for major part of adult life but eventually are bound to cause symptoms due to tethering of cord posteriorly, affirming an important proposition in natural history of such lesions. Intra‑dural exploration with release of arachnoidal bands and fibrous adhesions between two split cords along with excision of sac was associated with radiological non‑progression of syrinx, improved CSF flow dynamics ventrally and optimal outcome in short‑term follow up, confirming the cause‑effect relationship and emphasizing on the same as the primary surgical strategy. Oldest age of NTM at presentation is unique to the present study, with only other adulthood presentations of cervical cystic closed spinal dysraphisms being either CSF containing meningocele or rudimentary meningocele with absence of true ependymal‑lined myelocele.[22‑25] Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
1. Muthukumar N. Terminal and nonterminal myelocystoceles. J Neurosurg 2007;107:87‑97. 2. Gupta DK, Mahapatra AK. Terminal myelocystoceles: A series of 17 cases. J Neurosurg 2005;103:344‑52. 3. Rossi A, Piatelli G, Gandolfo C, Pavanello M, Hoffmann C, Van Goethem JW, et al. Spectrum of nonterminal myelocystoceles. Neurosurgery 2006;58:509‑15; discussion 509‑15. 4. Bhargava R, Hammond DI, Benzie RJ, Carlos E, Ventureyra G, Higgins MJ, et al. Prenatal demonstration of a cervical myelocystocele. Prenat Diagn 1992;12:653‑9. 5. Carmody RB, Jane J Jr, Shaffrey ME, Kaufman D. Complete thoracic myelocystocele: A rare benign spinal dysraphism with clinical significance. Arch Dis Child 2012;97:241‑2. 6. Chandra RV, Kumar PM. Cervical myelocystocele: Case report and review of literature. J Pediatr Neurosci 2011;6:55‑7. 7. Gressot LV, Mohila CA, Jea A, Luerssen TG, Bollo RJ. Cervicothoracic nonterminal myelocystocele with mature teratoma. J Neurosurg Pediatr 2014;13:204‑8. 8. Khandelwal A, Tandon V, Mahapatra AK. An unusual case of 4 level spinal dysraphism: Multiple composite type 1 and type 2 split cord malformation, dorsal myelocystocele and hydrocephalous. J Pediatr Neurosci 2011;6:58‑61. 9. Klein O, Coulomb MA, Ternier J, Lena G. Cervical myelocystocele: Prenatal diagnosis and therapeutical considerations. Childs Nerv Syst 2009;25:523‑6. 10. Nishino A, Shirane R, So K, Arai H, Suzuki H, Sakurai Y. Cervical myelocystocele with chiari ii malformation: Magnetic resonance imaging and surgical treatment. Surg Neurol 1998;49:269‑73. 11. Ochiai H, Kawano H, Miyaoka R, Nagano R, Kohno K, Nishiguchi T, et al. Cervical (non‑terminal) myelocystocele associated with rapidly progressive hydrocephalus and chiari type ii malformation‑‑case report. Neurol Med Chir (Tokyo) 2010;50:174‑7. 12. Pang D, Zovickian J, Oviedo A, Moes GS. Limited dorsal myeloschisis. A distinctive clinicopathological entity. Neurosurgery 2010;67:1555‑79; discussion 1579‑80. 13. Steinbok P, Cochrane DD. The nature of congenital posterior cervical or cervicothoracic midline cutaneous mass lesions. Report of eight cases. J Neurosurg 1991;75:206‑12. 14. Suneson A, Kalimo H. Myelocystocele with cerebellar heterotopia. Case report. J Neurosurg 1979;51:392‑6. 15. McLone DG, Naidich TP. Terminal myelocystocele. Neurosurgery 1985;16:36‑43. 16. Tibbles L, Wiley MJ. A comparative study of the effects of retinoic acid given during the critical period for inducing spina bifida in mice and hamsters. Teratology 1988;37:113‑25. 17. Schmitt HP, Kawakami M. Unusual split of the spinal cord in a caudal regression syndrome with myelocystocele. Brain Dev 1982;4:469‑74. 18. Carey JC, Greenbaum B, Hall BD. The OEIS complex (omphalocele, exstrophy, imperforate anus, spinal defects). Birth Defects Orig Artic Ser 1978;14:253‑63. 19. Habibi Z, Nejat F, Tajik P, Kazmi SS, Kajbafzadeh AM. Cervical myelomeningocele. Neurosurgery 2006;58:1168‑75; discussion 1168‑75. 20. Salomao JF, Cavalheiro S, Matushita H, Leibinger RD, Bellas AR, Vanazzi E, et al. Cystic spinal dysraphism of the cervical and upper thoracic region. Childs Nerv Syst 2006;22:234‑42. 707
Letters to Editor
21. Pang D, Dias MS. Cervical myelomeningoceles. Neurosurgery 1993;33:363‑72. 22. Denaro L, Padoan A, Manara R, Gardiman M, Ciccarino P, d’Avella D. Cervical myelomeningocele in adulthood: Case report. Neurosurgery 2008;62:E1169‑71. 23. Duz B, Arslan E, Gonul E. Cervical congenital midline meningoceles in adults. Neurosurgery 2008;63:938‑44. 24. Wang H, Yu W, Zhang Z, Lu Y, Li X. Cervical rudimentary meningocele in adulthood. J Neurosurg Spine 2013;18:511‑4. 25. Konya D, Dagcinar A, Akakin A, Gercek A, Ozgen S, Pamir MN. Cervical meningocele causing symptoms in adulthood: Case report and review of the literature. J Spinal Disord Tech 2006;19:531‑3.
poor flow rate. Patient underwent L4–5 laminotomy, had tethering of cord with thick filum attached to the dorsal dura. Detethering was carried out. Intra‑operatively, there was upward recoil of cord. Post‑operatively, patient had subjective improvement in weakness and numbness beginning immediately, with power of 5/5 both lower limbs at 6 weeks. MRI done 6 weeks later showed significant resolution of syrinx and tonsillar descent as compared to pre‑operative MRI [Figure 2].
Access this article online
Syringomyelia associated with tethered cord and spinal dysraphism is usually seen below vertebral level T6.[1] Holocord syrinx associated with tethered cord is unusual and creates dilemma of initial surgical strategy between foramen magnum decompression and detethering. The congenital effect of tethering as early as the phase of gastrulation might influence neurulation or post‑neurulation caudo‑cranial vertebral growth collision causing altered cerebrospinal fluid (CSF) dynamics, as indicated by occipitalization of atlas.[2,3]
Quick Response Code:
Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.149447
Received: 06-07-2014 Review completed: 12-08-2014 Accepted: 03-10-2014
The triad of holocord syringomyelia, Chiari malformation and tethered cord: Amelioration with simple detethering – A case for revisiting traction hypothesis? Sir, Chiari malformation is a common cause of cervical syringomyelia, extending caudally holocord occasionally, warranting foramen magnum decompression. The triad of Chiari malformation, holocord syringomyelia, and tethered cord is rare and poses therapeutic dilemma in choosing between foramen magnum decompression and filum detethering as the initial surgical strategy. We present a similar rare case. A 12‑year‑old boy presented with progressive weakness and decreased sensation over both lower limbs of 2 years and hesitancy and slow stream of urine of 6‑months duration. Examination revealed swelling low back, weakness of both lower limbs (right 4/5, left 4+/5), high stepping gait, and suspended/dissociated sensory impairment in upper limbs. Magnetic resonance imaging (MRI) demonstrated syrinx extending from C2 to L3 with cord tethered at L4–5 level, cerebellar tonsillar descent of 4 mm, occipitalization of atlas, and no hydrocephalus [Figure 1]. Uroflowmetry revealed 708
a
b
c
Figure 1: Pre-operative MRI
Figure 2: Post-operative MRI
Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
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support clip and groove of the base ring are in line, the ideal fulcrum is lost and force can be applied along the lead. Our report describes lead migration and the technical nuances associated with positioning of the Stimloc cap to the burr hole cover during DBS surgery.
Zion Zibly, Mayur Sharma, Andrew Shaw, Esmiralda Yeremeyeva, Milind Deogaonkar, Ali Rezai Department of Neurosurgery, Center of Neuromodulation, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA E‑mail: [email protected]
References Figure 4: Merged before and after cap placement fluoroscopy. Placement of the cap caused lateral shift directly below the Stimloc device with subsequent dorsal shift in lead placement (enlarged with contacts highlighted)
1.
Alex Mohit A, Samii A, Slimp JC, Grady MS, Goodkin R. Mechanical failure of the electrode wire in deep brain stimulation. Parkinsonism Related Disord 2004;10:153‑6. 2. Chan DT, Zhu XL, Yeung JH, Mok VC, Wong E, Lau C, et al. Complications of deep brain stimulation: A collective review. Asian J Surg 2009;32:258‑63. 3. Ray CD. Burr‑hole ring‑cap and electrode anchoring device. Technical note. J Neurosurg 1981;55:1004‑6. 4. Sharma M, Rhiew R, Deogaonkar M, Rezai A, Boulis N. Accuracy and precision of targeting using frameless stereotactic system in deep brain stimulator implantation surgery. Neurol India 2014;62:503‑9. Access this article online
a
b
Figure 5: (a) Support clip positioned in line with the groove of the base ring. (b) Ideal positioning of the support clip in relation to the base ring
through the Leksell cross hairs targeting system adapter was performed to confirm the position of electrode. The support clip (“pacman”) was positioned onto the base ring of the Stimloc system to secure the lead and fluoroscopy repeated. The lead was then carefully released from the robotic drive and no movement of the electrode was confirmed [Figure 2]. The cap was placed and fluoroscopy was repeated [Figure 3]. Before and after cap fluoroscopy images were merged [Figure 4] and lead was noted to have migrated approximately 2 mm dorsal from the target. The cap was removed and the lead was confirmed to revert back to the same starting depth position. The locking slot of the support clip was oriented parallel with the groove in the burr hole base ring. Since the lead wire appeared to angle upwards with placement of the cap, the team suggested a more perpendicular placement of the locking slot of the support clip relative to the groove in the base ring. The support clip was repositioned perpendicular to the groove and fluoroscopy confirmed that the lead was at the original desired depth. The ideal orientation of the support clip is to position the static side of the V‑shaped opening at approximately 90 degrees to the exit slot (Medtronic Stimloc Technical Manual, Medtronic Inc, 2007) [Figure 5]. When the 704
Quick Response Code:
Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.149441
Received: 11-07-2014 Review completed: 09-12-2014 Accepted: 16-12-2014
Non‑terminal cervical myelocystocele: Unusual cause of spastic quadriparesis in an adult Sir, Terminal and non‑terminal variants of myelocystocele are divided on anatomic location and postulated hypothesis of origin. [1,2] Former is a disorder of retrogressive differentiation (secondary neurulation) compared to limited dorsal myeloschisis (primary neurulation) in latter.[1,3] To the best of author’s knowledge, till date only 38 cases of non‑terminal myelocystocele (NTM or equivalent pathology) [1,3‑14] have been published in literature [Table 1] with most common age of presentation being neonates and infants. Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
Yes (USG)
Yes (USG and MRI) No
4 year/F
6 year/F
3 days/F
5 days/F
Khandelwal et al. (2011)[8]
Chandra et al. (2011)[6] Carmody et al. (2012)[5] Gressot et al. (2014)[7] Present study (2014)
No
Complete
Complete
Cervico‑thoracic Cervical
Abortive
Complete
Abortive
Abortive
Thoracic
Cervical
Thoracic
Cervical 3 Upper thoracic 1 Lower thoracic 1 Thoraco‑lumbar 1 Cervical
Cervical
ACM II Hydromyelia
ACM II Low lying cord Arrested HCP ACM II Syringomyelia
None
SCM I SCM II HCP Bifid fatty filum Dermal coccygeal sinus Syringomyelia
ACM II HCP
Resection, detethering, foramen magnum decompression and lax duraplasty Resection+Detethering – 2 Resection only ‑ 3
Resection, detethering
Resection, detethering and excision of tumor VP∆ shunt+resection of MCC# ‑ 3 MC° resection+detethering – 3 Extradural excision of MC ‑ 2
Spastic quadriparesis Incontinence
Normal
Normal
Normal
Paraparesis
Normal
NA
Normal
NA
Normal (1 year)
Normal (7 months)
Normal – 2 B/l VUR, increased HCP and increased hydromyelia – 2 (17 months)
Normal (2 years)
Normal except positive babinski sign in right foot (18 mo) Retethering with neurological deterioration – 5 Normal – 3 (31 months) Normal (6 mo)
Outcome (follow up)
Resection, detethering
Resection, detethering
Resection, detethering
Reduced spasticity Improved power (6 mo)
Normal (3 mo)
Normal (6 mo)
Resection, detethering followed by Normal (immediate post‑op); VP shunt shunt done for respiratory distress Repair of MCC Same as before at discharge. Excision of 2 level SCM I Further follow up NA Excision of SCM II VP shunt Excision of dermal sinus and filum Resection, Detethering Normal (Follow up NA)
Resection, intra‑dural exploration and detethering
Resection, detethering
Paraplegia+ Resection+Detethering ‑ 9 Incontinence – 1 Normal – 8
Normal with respiratory distress Normal
Normal
Normal
Normal
Neurological Surgery examination
‡
$
Variant - Based on Rossi et al. classification, αNA - Not available, *ACM II - Arnold‑chiari malformation type II, †HCP - Hydrocephalus, ∆VP - Ventriculo‑peritoneal, #MCC - Myelocystocele, ⁰MC - Meningocele, USG ‑ Ultrasonography, MRI - Magnetic resonance imaging, ∞VUR - Vesicoureteric reflex, §SCM - Split cord malformation, ^LDM - Limited dorsal myeloschisis
42 year/M
No
Infant/F
Ochiai et al. (2010)[11]
No
9 Infants NA (10 days to 3 months) 9F 2 mo/F Yes (USG and MRI) 6 patients No
Muthukumar et al. (2007)[1]
Klein et al. (2009)[9] Pang et al. (2010)[12]
Yes (USG) – 3 Cervical – 3 No – 3 Thoracic – 2 Lumbar ‑ 1
6 children (1 day to 6 years) 4 M/2 F
Rossi et al. (2006)[3]
Cervical – 1 Thoracic – 6 Lumbosacral ‑ 2
Complete
Cervical
None
Hydromyelia – 3 ACM II – 5 HCP – 5
Cerebellar heterotropia
Associated anomalies
ACM II – 3 HCP – 1 Hydromyelia – 2 Neurenteric cyst – 1 Filar lipoma – 1 Complete – 3 Aqueductal stenosis – 1 Abortive ‑ 6 ACM II – 1 Low lying conus medullaris – 2 SCM§ ‑ 1 Complete Syringomyelia Lipoma LDM^‑Saccular NA MCC (≈Complete)
Complete
Cervical
Yes (USG‡/ MRI) No
Bhargava et al. 1 day/M (1992)[4] Nishino et al. 2 days/F (1998)[10] Complete – 3 Abortive ‑ 3
Cervical – 7 Complete – 3 Cervico‑thoracic ‑ 1 Abortive ‑ 5
Complete
Variant$
NA α
Location Cervico‑thoracic
Prenatal diagnosis
No
Age/sex
Suneson et al. 21 mo/M (1979)14 Steinbok et al. 8 Infants (1991)[13] (1 day to 9 months)
Author (year)
Table 1: Summary of non‑terminal myelocystocele: Patient profile, surgical modality and outcome
Letters to Editor
705
Letters to Editor
We present a unique case of cervical NTM in a 42‑year‑old male who presented with progressive spastic ascending quadriparesis (power 4/5 below C6 myotome), decreased sensation (below C6 dermatome) for two years, and upper motor neuron type bowel and bladder dysfunction for eight months. Local examination revealed 5 × 4 × 3 cm midline non‑tender cystic saccular skin covered lesion with dysplastic skin in midline along with hypertrichosis and positive fluctuation test [Figure 1a]. Magnetic resonance imaging (MRI) of craniospinal axis revealed arrested hydrocephalus, mild type I Arnold‑Chiari malformation II [3] (ACM II) with cerebellar tissue pegging through foramen magnum, fused C6/7 and D1/2 vertebrae, spina bifida defect at C6‑C7 level, tenting of open‑book configuration spinal cord at C6‑C7 level with posteriorly tethered cystic dilation continuous with hydromyelic cavity, attached to dome of cystic meningocele lying below intact skin [Figure 1b‑d). Abnormal cerebrospinal fluid (CSF) flow dynamics are seen in dilated sub‑arachnoid space ventral to cord at the level of cord tethering along with syrinx cranially. Dorsally central canal is open and continuous with ependymal lined cyst tethered to dysplastic skin dorsally. Radiological diagnosis of NTM (Rossi type B) [3] was made. Intra‑operatively fused posterior elements of C6/7 with a midline spina bifida defect was seen with dural sac meningocele containing ependymal lined and extending intra‑spinally to invest on dorsal aspect of spinal cord and communicating with dilated central canal [Figure 2]. Complete excision of tethering band and intra‑spinal adhesiolysis was done to release cord adequately. Histopathological examination revealed microscopic nests of glial tissue along with adipose tissue in a fibro‑collagenous background confirming the diagnosis of myelocystocele [Figure 3]. Patient had a clinical improvement from neurological grade three to two post‑operatively (as classified by Pang et al.),[12] which remained stable till last follow up at six months. Interval MRI done after three months was suggestive of stable ventricular size, reduction of CSF space ventral to cord with improved flow dynamics and evidence of detethered spinal cord with non‑progression of syrinx and ACM II [Figure 4]. Myelocystocele is a rare variant of closed spinal dysraphism characterized by skin covered mass located posteriorly in midline, narrow spina bifida defect, cerebrospinal fluid cyst, expanded dural sheath with varying amounts of dorsal fat continuous with sub‑cutaneous fat.[15] Though no proven genetic basis exists, it has been associated with intrauterine exposure to retinoic acid, [16] loperamide [17] and hydantoin. [18] Developmental origin of NTM is hypothesized by limited dorsal myeloschisis leading to delayed 706
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Figure 1: (a) Pre‑operative clinical photograph demonstrating midline cystic cervical lesion covered with dysplastic skin suggestive of non‑terminal myelocystocele (MCC). (b) Axial T2W magnetic resonance image (MRI) demonstrating “open‑book” configuration of cord with hydromyelic cavity continuing as myelocele (MYC) through spina‑bifida (SB) bony defect and investing on outer cystic cavity of dural meningocele (MC) below intact skin. (c) and (d) Saggital T2W MRI showing C6/7 and D1/2 block vertebrae (BV), mild chiari II malformation (ACM) features with cerebellar pegging through foramen magnum. Cord is tented dorsally to meningocele (MC) sac with resultant increased sub‑arachnoidal space along with abnormal cerebrospinal fluid flow dynamics ventrally creating flow voids (FV)
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Figure 2: Intra‑operative photograph (a) demonstrating myelocele (MYC) sac tethered dorsally to meningocele (MC) sac and its relation to normal cord. (b) After detethering, small part of residual myelocele sac seen with thinned out distal cord (DC) and proximal cord (PC) owing to release of syringomyelic cavity communicating with myelocele
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Figure 3: HPE findings – (a) Photomicrograph showing fibro‑collagenous tissue and fibro‑adipose tissue (H and E x100). (b) Photomicrograph shows small islands of glial tissue along with neuro‑melanin (arrow) admixed in a fibro‑collagenous background (H and E x100)
disjunction of ectoderm and neuro‑ectoderm in final stages of primary neurulation, thereby leaving small defect in midline.[1,3] Surrounding mesenchyme and ectodermal elements overgrow and cover this small defect, leaving on small part of dorsal cord tissue connected to skin in form of either well formed Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
Letters to Editor
Amol Raheja, Deepak Kumar Gupta, Aasma Nalwa1, Vaishali Suri1, Bhawani Shankar Sharma
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Departments of Neurosurgery and Gamma Knife, and 1Pathology, All India Institute of Medical Sciences, New Delhi, India E‑mail: [email protected]
References
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Figure 4: Follow up (a) ‑ saggital, (b) and (c) – axial magnetic resonance images after six months demonstrating completely untethered cord (UC) with remnant hydromyelic cavity (HC) and reduced ventral sub‑arachnoidal space along with no evidence of flow voids (NFV) attributing to laminar cerebrospinal fluid flow pattern after procedure. There is evidence of non‑progression of chiari II malformation compared to pre‑operative imaging
myelocystocele (complete variant, Rossi type B, myelocystocele, limited dorsal myeloschisis with saccular myelocystocele and myelocystocele consisting of a second ependymal lined cyst herniated inside a meningocele) or neuro‑fibro‑vascular band (abortive variant, Rossi type A, fibroneurovascular stalk, limited dorsal myeloschisis with stalk and cystic spinal dysraphism with neuro‑glial stalk) based on classification given by Rossi et al.,[3] Habibi et al.,[19] Pang et al.[12] and Salamao et al.,[20] respectively. Severity of symptoms is unrelated to location of lesion but probably increases with increasing age.[12] Surgical strategy aims at excision, intra‑dural exploration and complete detethering for optimal outcome, with poor neurological outcome associated when only extra‑dural excision is undertaken. [21] The index case ponders us to acknowledge that such lesions may remain asymptomatic for major part of adult life but eventually are bound to cause symptoms due to tethering of cord posteriorly, affirming an important proposition in natural history of such lesions. Intra‑dural exploration with release of arachnoidal bands and fibrous adhesions between two split cords along with excision of sac was associated with radiological non‑progression of syrinx, improved CSF flow dynamics ventrally and optimal outcome in short‑term follow up, confirming the cause‑effect relationship and emphasizing on the same as the primary surgical strategy. Oldest age of NTM at presentation is unique to the present study, with only other adulthood presentations of cervical cystic closed spinal dysraphisms being either CSF containing meningocele or rudimentary meningocele with absence of true ependymal‑lined myelocele.[22‑25] Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
1. Muthukumar N. Terminal and nonterminal myelocystoceles. J Neurosurg 2007;107:87‑97. 2. Gupta DK, Mahapatra AK. Terminal myelocystoceles: A series of 17 cases. J Neurosurg 2005;103:344‑52. 3. Rossi A, Piatelli G, Gandolfo C, Pavanello M, Hoffmann C, Van Goethem JW, et al. Spectrum of nonterminal myelocystoceles. Neurosurgery 2006;58:509‑15; discussion 509‑15. 4. Bhargava R, Hammond DI, Benzie RJ, Carlos E, Ventureyra G, Higgins MJ, et al. Prenatal demonstration of a cervical myelocystocele. Prenat Diagn 1992;12:653‑9. 5. Carmody RB, Jane J Jr, Shaffrey ME, Kaufman D. Complete thoracic myelocystocele: A rare benign spinal dysraphism with clinical significance. Arch Dis Child 2012;97:241‑2. 6. Chandra RV, Kumar PM. Cervical myelocystocele: Case report and review of literature. J Pediatr Neurosci 2011;6:55‑7. 7. Gressot LV, Mohila CA, Jea A, Luerssen TG, Bollo RJ. Cervicothoracic nonterminal myelocystocele with mature teratoma. J Neurosurg Pediatr 2014;13:204‑8. 8. Khandelwal A, Tandon V, Mahapatra AK. An unusual case of 4 level spinal dysraphism: Multiple composite type 1 and type 2 split cord malformation, dorsal myelocystocele and hydrocephalous. J Pediatr Neurosci 2011;6:58‑61. 9. Klein O, Coulomb MA, Ternier J, Lena G. Cervical myelocystocele: Prenatal diagnosis and therapeutical considerations. Childs Nerv Syst 2009;25:523‑6. 10. Nishino A, Shirane R, So K, Arai H, Suzuki H, Sakurai Y. Cervical myelocystocele with chiari ii malformation: Magnetic resonance imaging and surgical treatment. Surg Neurol 1998;49:269‑73. 11. Ochiai H, Kawano H, Miyaoka R, Nagano R, Kohno K, Nishiguchi T, et al. Cervical (non‑terminal) myelocystocele associated with rapidly progressive hydrocephalus and chiari type ii malformation‑‑case report. Neurol Med Chir (Tokyo) 2010;50:174‑7. 12. Pang D, Zovickian J, Oviedo A, Moes GS. Limited dorsal myeloschisis. A distinctive clinicopathological entity. Neurosurgery 2010;67:1555‑79; discussion 1579‑80. 13. Steinbok P, Cochrane DD. The nature of congenital posterior cervical or cervicothoracic midline cutaneous mass lesions. Report of eight cases. J Neurosurg 1991;75:206‑12. 14. Suneson A, Kalimo H. Myelocystocele with cerebellar heterotopia. Case report. J Neurosurg 1979;51:392‑6. 15. McLone DG, Naidich TP. Terminal myelocystocele. Neurosurgery 1985;16:36‑43. 16. Tibbles L, Wiley MJ. A comparative study of the effects of retinoic acid given during the critical period for inducing spina bifida in mice and hamsters. Teratology 1988;37:113‑25. 17. Schmitt HP, Kawakami M. Unusual split of the spinal cord in a caudal regression syndrome with myelocystocele. Brain Dev 1982;4:469‑74. 18. Carey JC, Greenbaum B, Hall BD. The OEIS complex (omphalocele, exstrophy, imperforate anus, spinal defects). Birth Defects Orig Artic Ser 1978;14:253‑63. 19. Habibi Z, Nejat F, Tajik P, Kazmi SS, Kajbafzadeh AM. Cervical myelomeningocele. Neurosurgery 2006;58:1168‑75; discussion 1168‑75. 20. Salomao JF, Cavalheiro S, Matushita H, Leibinger RD, Bellas AR, Vanazzi E, et al. Cystic spinal dysraphism of the cervical and upper thoracic region. Childs Nerv Syst 2006;22:234‑42. 707
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21. Pang D, Dias MS. Cervical myelomeningoceles. Neurosurgery 1993;33:363‑72. 22. Denaro L, Padoan A, Manara R, Gardiman M, Ciccarino P, d’Avella D. Cervical myelomeningocele in adulthood: Case report. Neurosurgery 2008;62:E1169‑71. 23. Duz B, Arslan E, Gonul E. Cervical congenital midline meningoceles in adults. Neurosurgery 2008;63:938‑44. 24. Wang H, Yu W, Zhang Z, Lu Y, Li X. Cervical rudimentary meningocele in adulthood. J Neurosurg Spine 2013;18:511‑4. 25. Konya D, Dagcinar A, Akakin A, Gercek A, Ozgen S, Pamir MN. Cervical meningocele causing symptoms in adulthood: Case report and review of the literature. J Spinal Disord Tech 2006;19:531‑3.
poor flow rate. Patient underwent L4–5 laminotomy, had tethering of cord with thick filum attached to the dorsal dura. Detethering was carried out. Intra‑operatively, there was upward recoil of cord. Post‑operatively, patient had subjective improvement in weakness and numbness beginning immediately, with power of 5/5 both lower limbs at 6 weeks. MRI done 6 weeks later showed significant resolution of syrinx and tonsillar descent as compared to pre‑operative MRI [Figure 2].
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Syringomyelia associated with tethered cord and spinal dysraphism is usually seen below vertebral level T6.[1] Holocord syrinx associated with tethered cord is unusual and creates dilemma of initial surgical strategy between foramen magnum decompression and detethering. The congenital effect of tethering as early as the phase of gastrulation might influence neurulation or post‑neurulation caudo‑cranial vertebral growth collision causing altered cerebrospinal fluid (CSF) dynamics, as indicated by occipitalization of atlas.[2,3]
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Website: www.neurologyindia.com PMID: *** DOI: 10.4103/0028-3886.149447
Received: 06-07-2014 Review completed: 12-08-2014 Accepted: 03-10-2014
The triad of holocord syringomyelia, Chiari malformation and tethered cord: Amelioration with simple detethering – A case for revisiting traction hypothesis? Sir, Chiari malformation is a common cause of cervical syringomyelia, extending caudally holocord occasionally, warranting foramen magnum decompression. The triad of Chiari malformation, holocord syringomyelia, and tethered cord is rare and poses therapeutic dilemma in choosing between foramen magnum decompression and filum detethering as the initial surgical strategy. We present a similar rare case. A 12‑year‑old boy presented with progressive weakness and decreased sensation over both lower limbs of 2 years and hesitancy and slow stream of urine of 6‑months duration. Examination revealed swelling low back, weakness of both lower limbs (right 4/5, left 4+/5), high stepping gait, and suspended/dissociated sensory impairment in upper limbs. Magnetic resonance imaging (MRI) demonstrated syrinx extending from C2 to L3 with cord tethered at L4–5 level, cerebellar tonsillar descent of 4 mm, occipitalization of atlas, and no hydrocephalus [Figure 1]. Uroflowmetry revealed 708
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Figure 1: Pre-operative MRI
Figure 2: Post-operative MRI
Neurology India | Nov-Dec 2014 | Vol 62 | Issue 6
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