British Journal of Neurosurgery
ISSN: 0268-8697 (Print) 1360-046X (Online) Journal homepage: http://www.tandfonline.com/loi/ibjn20
The pathogenesis of migrating pseudomeningocele Zerui Zhuang & Bin Liu To cite this article: Zerui Zhuang & Bin Liu (2015) The pathogenesis of migrating pseudomeningocele, British Journal of Neurosurgery, 29:3, 445-446, DOI: 10.3109/02688697.2014.996526 To link to this article: http://dx.doi.org/10.3109/02688697.2014.996526
Published online: 22 Dec 2014.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ibjn20 Download by: [University of Lethbridge]
Date: 06 November 2015, At: 00:29
British Journal of Neurosurgery, June 2015; 29(3): 445–446 © 2014 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2014.996526
LETTER TO THE EDITOR
Downloaded by [University of Lethbridge] at 00:29 06 November 2015
The pathogenesis of migrating pseudomeningocele We read with interest the case report of de Jong et al.1 describing two cases of spontaneous intracerebellar migration of a pseudomeningocele. In this report, the authors indicate that the probable mechanism is a slow but progressive cerebrospinal fluid (CSF) movement into the pseudomeningocele with secondary herniation or dissection through a weakened dura into the cerebellum. We had met some cases with suboccipital pseudomeningocele following posterior fossa surgery. Although there are no migrations into the cerebellum in our cases, we would like to add our view on migrating pseudomeningocele causing posterior fossa syndrome. We believe that neck movement may drive the migration of a suboccipital pseudomeningocele. Iatrogenic pseudomeningoceles may or may not be associated with an arachnoid tear, but a dural tear is necessary for one to form.2 The intradural pressure of the CSF causes a constant outflow of CSF through the dural tear, which forms a sac of epidural CSF collection in the traumatized postoperative bed of the cervical musculature. Therefore, a communication is formed between the subarachnoid space and the epidural sac of CSF collection. If the arachnoid is not violated, the arachnoid membrane may subsequently herniate through the dural defect. When intact arachnoid herniates into the sac, the communication is more likely to remain open and form a pseudomeningocele, whereas when an arachnoidal tear occurs, the likelihood of closure of the communication is greater. Sometimes the communication is a one-way direction between the subarachnoid space and the sac in patients with the pseudomeningocele. Due to the formation of a one-way ball-valve with a tissue flap, only allowing a one-way flow of CSF into the pseudomeningocele. Occasionally, there is a lack of communication between the subarachnoid space and the sac in few patients; in this respect it resembles the speculation by de Jong et al. This lack of communication or a one-way communication is probably secondary to the scarring of soft-tissue wound. Anyway, a pseudomeningocele is to be formed in postoperative bed of the cervical musculatures. The sac of pseudomeningocele is extruded by the muscles and other soft tissues in the occipitocervical region of neck during the flexion of the neck (Fig. 1), and extruded by the occipital bone and the supercervical spine during the extension of the neck (Fig. 2). In addition, the direction of the force generated by neck movement is from the extracranial space to the intracranial cavity. On the contrary, the direction of the force generated by CSF pulsation is from the intracranial cavity to the extracranial space. The repeated extrusion of the
Fig. 1. The sac of pseudomeningocele (SP) is extruded by the muscles and other soft tissues in the occipitocervical region of neck during the flexion of the neck. The direction of the force (arrow) acting on the sac is from the extracranial space to the intracranial cavity.
sac results in the increase of the sac cavity pressure, forming a pressure gradient between the sac and the cerebellum followed by the migration of CSF in the pseudomeningocele into the cerebellar parenchyma through a weak area in the dura.
Fig. 2. The sac of pseudomeningocele (SP) is extruded by the occipital bone and the super-cervical spine during the extension of the neck. The direction of the force (arrow) acting on the sac is from the extracranial space to the intracranial cavity.
445
446
Z. Zhuang & B. Liu
Downloaded by [University of Lethbridge] at 00:29 06 November 2015
Zerui Zhuang and Bin Liu Department of Neurosurgery Second Affiliated Hospital Shantou University Medical College Shantou, Guangdong, P. R. China
References 1. de Jong L, Engelborghs K, Vandevenne J, Weyns F. Migrating pseudomeningocele causing posterior fossa syndrome. Br J Neurosurg 2012;26:537–9. 2. Hawk MW, Kim KD. Review of spinal pseudomeningoceles and cerebrospinal fluid fistulas. Neurosurg Focus 2000;9:e5.
ISSN: 0268-8697 (Print) 1360-046X (Online) Journal homepage: http://www.tandfonline.com/loi/ibjn20
The pathogenesis of migrating pseudomeningocele Zerui Zhuang & Bin Liu To cite this article: Zerui Zhuang & Bin Liu (2015) The pathogenesis of migrating pseudomeningocele, British Journal of Neurosurgery, 29:3, 445-446, DOI: 10.3109/02688697.2014.996526 To link to this article: http://dx.doi.org/10.3109/02688697.2014.996526
Published online: 22 Dec 2014.
Submit your article to this journal
Article views: 21
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ibjn20 Download by: [University of Lethbridge]
Date: 06 November 2015, At: 00:29
British Journal of Neurosurgery, June 2015; 29(3): 445–446 © 2014 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2014.996526
LETTER TO THE EDITOR
Downloaded by [University of Lethbridge] at 00:29 06 November 2015
The pathogenesis of migrating pseudomeningocele We read with interest the case report of de Jong et al.1 describing two cases of spontaneous intracerebellar migration of a pseudomeningocele. In this report, the authors indicate that the probable mechanism is a slow but progressive cerebrospinal fluid (CSF) movement into the pseudomeningocele with secondary herniation or dissection through a weakened dura into the cerebellum. We had met some cases with suboccipital pseudomeningocele following posterior fossa surgery. Although there are no migrations into the cerebellum in our cases, we would like to add our view on migrating pseudomeningocele causing posterior fossa syndrome. We believe that neck movement may drive the migration of a suboccipital pseudomeningocele. Iatrogenic pseudomeningoceles may or may not be associated with an arachnoid tear, but a dural tear is necessary for one to form.2 The intradural pressure of the CSF causes a constant outflow of CSF through the dural tear, which forms a sac of epidural CSF collection in the traumatized postoperative bed of the cervical musculature. Therefore, a communication is formed between the subarachnoid space and the epidural sac of CSF collection. If the arachnoid is not violated, the arachnoid membrane may subsequently herniate through the dural defect. When intact arachnoid herniates into the sac, the communication is more likely to remain open and form a pseudomeningocele, whereas when an arachnoidal tear occurs, the likelihood of closure of the communication is greater. Sometimes the communication is a one-way direction between the subarachnoid space and the sac in patients with the pseudomeningocele. Due to the formation of a one-way ball-valve with a tissue flap, only allowing a one-way flow of CSF into the pseudomeningocele. Occasionally, there is a lack of communication between the subarachnoid space and the sac in few patients; in this respect it resembles the speculation by de Jong et al. This lack of communication or a one-way communication is probably secondary to the scarring of soft-tissue wound. Anyway, a pseudomeningocele is to be formed in postoperative bed of the cervical musculatures. The sac of pseudomeningocele is extruded by the muscles and other soft tissues in the occipitocervical region of neck during the flexion of the neck (Fig. 1), and extruded by the occipital bone and the supercervical spine during the extension of the neck (Fig. 2). In addition, the direction of the force generated by neck movement is from the extracranial space to the intracranial cavity. On the contrary, the direction of the force generated by CSF pulsation is from the intracranial cavity to the extracranial space. The repeated extrusion of the
Fig. 1. The sac of pseudomeningocele (SP) is extruded by the muscles and other soft tissues in the occipitocervical region of neck during the flexion of the neck. The direction of the force (arrow) acting on the sac is from the extracranial space to the intracranial cavity.
sac results in the increase of the sac cavity pressure, forming a pressure gradient between the sac and the cerebellum followed by the migration of CSF in the pseudomeningocele into the cerebellar parenchyma through a weak area in the dura.
Fig. 2. The sac of pseudomeningocele (SP) is extruded by the occipital bone and the super-cervical spine during the extension of the neck. The direction of the force (arrow) acting on the sac is from the extracranial space to the intracranial cavity.
445
446
Z. Zhuang & B. Liu
Downloaded by [University of Lethbridge] at 00:29 06 November 2015
Zerui Zhuang and Bin Liu Department of Neurosurgery Second Affiliated Hospital Shantou University Medical College Shantou, Guangdong, P. R. China
References 1. de Jong L, Engelborghs K, Vandevenne J, Weyns F. Migrating pseudomeningocele causing posterior fossa syndrome. Br J Neurosurg 2012;26:537–9. 2. Hawk MW, Kim KD. Review of spinal pseudomeningoceles and cerebrospinal fluid fistulas. Neurosurg Focus 2000;9:e5.
