- Email: [email protected]
Unusual Association Between Spontaneous Lateral Sphenoid Encephalocele and Chiari Malformation Type I: Endoscopic Repair Through a Transpterygoid Approach
Accepted Manuscript Unusual association between spontaneous lateral sphenoid encephalocele and Chiari malformation Type I: Endoscopic repair through a transpterygoid approach Daniele Starnoni, MD, Roy Thomas Daniel, MCh, Mercy George, Mahmoud Messerer, MD PII:
S1878-8750(16)30969-X
DOI:
10.1016/j.wneu.2016.09.112
Reference:
WNEU 4652
To appear in:
World Neurosurgery
Received Date: 27 April 2016 Revised Date:
22 September 2016
Accepted Date: 26 September 2016
Please cite this article as: Starnoni D, Daniel RT, George M, Messerer M, Unusual association between spontaneous lateral sphenoid encephalocele and Chiari malformation Type I: Endoscopic repair through a transpterygoid approach, World Neurosurgery (2016), doi: 10.1016/j.wneu.2016.09.112. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Starnoni 1
ACCEPTED MANUSCRIPT
Unusual association between spontaneous lateral sphenoid encephalocele and Chiari malformation Type I: Endoscopic repair through a transpterygoid approach
Messerer MD*
RI PT
Daniele Starnoni MD*; Roy Thomas Daniel, MCh*; Mercy George**; Mahmoud
*Neurosurgical Service, Centre Hospitalier Universitaire Vaudois (CHUV); Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
M AN U
University of Lausanne, Lausanne, Switzerland
SC
**ENT Service, Centre Hospitalier Universitaire Vaudois (CHUV); Faculty of Biology and Medicine,
Corresponding author: Daniele Starnoni
Rue du Bugnon 46 CH-1011 Lausanne, Switzerland +41 79 556 87 69
EP
[email protected]
TE D
Service de Neurochirurgie, Centre Hospitalier Universitaire Vaudois (CHUV)
AC C
Conflict of Interest: The authors declare that they have no conflict of interest.
Keywords: chiari malformation Type I, meningoencephalocele, encephalocele, sphenoid sinus, skull base, endoscopic surgery
Abbreviations list: (CMI) Chiari malformation Type I; (CSF) cerebrospinal fluid; (SLSCs) spontaneous lateral sphenoid encephaloceles; (IIH) idiopathic intracranial hypertension
Starnoni 2
ACCEPTED MANUSCRIPT Abstract
Background: Spontaneous meningoencephaloceles of the lateral sphenoid sinus are rare entities and their peculiar location represent a surgical challenge due to the importance of a wide exposure and skull base reconstruction. They are thought to arise from congenital base defect of the lateral sphenoid or in some cases have been postulated to represent a rare manifestation of altered CSF
RI PT
dynamics. We report the first case in literature of a Chiari malformation type I and a lateral sphenoid encephaloceles revising the theoretical etiology and surgical technique of endoscopic repair.
Case Description: A 50 year-old woman, with a surgical history of symptomatic Chiari malformation
SC
type I, presented with episodes of spontaneous CSF rhinorrhea. Radiological investigations revealed a left mesial temporal encephalocele herniating into the lateral recess of the sphenoid sinus and radiological features of altered CSF dynamics which may have played an etiological role. An
M AN U
endoscopic transpterygoid excision of the encephalocele and multilayer skull base repair was performed.
Conclusion: The association of SLSC with Chiari type I is distinctly unusual. Predisposing factors and disruption of CSF dynamics may play a major role in the developing of this rare complication in patients with CMI. Because of its distinct location, transethmoid or transpterygoid endoscopic
TE D
approaches represent an excellent surgical technique to treat these lesions thanks to their wide and direct visualization of the entire skull base defect following the encephalocele excision allowing an
AC C
EP
adequate multilayer repair and lateral sphenoid recess occlusion.
Starnoni 3
ACCEPTED MANUSCRIPT
Chiari malformation Type I (CMI) is a craniocervical junction disorder characterized by caudal displacement of the cerebellar tonsils at least 5 mm below the plane of the foramen magnum into the spinal canal. It may be congenital or acquired, the peak age of presentation 1
is 8 years in the pediatric population and 41 years in adults. The physiopathology of the clinical presentation is characterized by disruption of normal cerebrospinal fluid (CSF) flow
RI PT
and altered CSF dynamics at the level of the foramen magnum leads to isolation of
intracranial compartment causing transient elevations of intracranial pressure which is
commonly associated with cervical syringomyelia, reported in 30-70%, and hydrocephalus in 1
7-9%.
2-8
SC
Numerous associations with CMI have been reported
but a herniation of
intracranial contents through a bony defect (meningocele or meningoencephalocele),
to the best of our knowledge.
M AN U
characteristic of Chiari Type III, in association with a CMI has not been previously described
Non-traumatic encephalocele may be congenital if associated with skull base bony defect and in its absence, it has been hypothesized to represent a rare consequence of chronic intracranial hypertension.
9
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We report a unique case in literature of CMI and a lateral sphenoid encephalocele in a 50 year-old patient. The radiological characteristics in association with the physiopathological hypothesis are reviewed in order to better define this rare association. We
EP
also describe the surgical approach and the skull base reconstruction technique for these
AC C
challenging lesions.
Case Report
A 50 year-old woman was evaluated for a left mesial temporal encephalocele
herniating into the lateral recess of the sphenoid sinus presenting with episodes of spontaneous CSF rhinorrhea. The patient had a previous history of symptomatic CMI and had undergone, seven years before the current admission, a foramen magnum decompression with expansive duroplasty, followed by ventriculoperitoneal shunt placement, 3 months later, for persistent signs and symptoms of intracranial hypertension without ventricular dilation.
Starnoni 4
ACCEPTED MANUSCRIPT
The values of the opening pressure were not reported in her dossier, the magnetic resonance venography report was normal. At the time of our first consultation we reviewed the clinico-radiological dossier of the patient and identified the encephalocele as being present at the same time of the CMI diagnosis (Figure 1). Axial and coronal bone CT images showed multiple ovoid bony defects
RI PT
in the greater wing of the sphenoid bone and a focal bony dehiscence of the lateral wall of the left sphenoid sinus with soft tissue herniating into a large pneumatized lateral sphenoid recess (Figure 2). T1 and T2- weighted sequences demonstrated the contents of the
SC
herniation as an encephalocele. MRI images also showed coexisting empty sella and bilateral prominent Meckel’s cave (Figure 3). The ventricular size was normal with no hydrocephalus and a functional ventriculo-peritoneal shunt.
M AN U
In view of progressive increase in size of the encephalocele on subsequent MRIs it was decided to perform an endoscopic transpterygoid excision of the encephalocele. We performed an anterior and posterior ethmoidectomy with complete middle turbinectomy along with the creation of a mucoperiostial vascularized middle turbinate flap. A transethmoid sphenoidotomy and partial maxillary antrostomy was performed. The mucosa of the posterior
TE D
wall was reflected and the anterior perpendicular process of the palatine bone was dissected and drilled to expose and resect part of the medial plate of pterygoid process allowing a direct visualization of the lateral recess of the sphenoid sinus. The 30-degree angled endoscope
EP
allowed us to clearly visualize the encephalocele in the lateral recess of the sphenoid sinus protruding through a small round bony defect. It was meticulously dissected and excised, care
AC C
was taken to cauterize and reduce the skull encephalocele stump at the skull base. We then performed a multi-layered skull base dural and bony repair. A fascia lata graft and tissue sealant was used for the dural repair followed by osseous reconstruction (middle turbinate bone graft) placed as an on-lay on top of the fascia and sunk into the skull base defect (Figure 3). The mucoperiostial vascularized middle turbinate flap was then used to consolidate and seal the skull base repair. The final reconstruction was further secured by a layer of bioabsorbable artificial dura and free-fat graft followed by the application of a synthetic sealant. The lateral recess was occluded with an autologous fat graft (video).
Starnoni 5
ACCEPTED MANUSCRIPT
The patient had uneventful post-operative course and a three- and six-month followup CT showed no signs of recurrence of the encephalocele and the patient didn’t experience any signs of symptoms of intracranial hypertension confirming the patency of the shunt (Figure 4).
RI PT
Discussion
Meningoencephaloceles can be categorized as congenital in case of a pre-existing skull base defect or associated with trauma, surgery or malignancies. In absence of any
10
meningoencephaloceles.
SC
predisposing factors they are defined as spontaneous and account for less than 9% of all
In the subset of spontaneous encephaloceles the lateral sphenoid
recess represents a very rare location and these meningoencephaloceles are more likely to
M AN U
occur in the presence of a large pneumatization of the lateral recess of the sphenoid sinus; in such cases the herniation can become apparent with a CSF leak and thereby pose a risk for ascending infections.
Many studies have focused on the etiopathology of this spontaneous lateral sphenoid encephaloceles (SLSCs) and initially it was believed to be correlated with a persistent lateral 11
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craniopharyngeal (Sternberg) canal. More recently, radiological and clinical observations of association between SLSCs and intracranial hypertension supports the hypothesis that a CSF dynamic disruption and increased intracranial hypertension may be the leading cause of
EP
this rare entity. A strong correlation between SLSCs and idiopathic intracranial hypertension (IIH) has been widely reported in many series in almost 70% of the patients
12,13
suggesting
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that, in this peculiar case, the encephalocele repair alone may have a high risk of 14
recurrence. This supposition has also been corroborated by reports of patients presenting signs of increased intracranial pressure after treatment of the encephalocele and skull base repair, suggesting a decompressive role of the encephalocele for alleviating raised 15
intracranial pressure.
In this light Carrau et al. offered an algorithm based on opening
pressure established 3-5 days after the endoscopic repair by means of lumbar puncture in order to identify prospectively occult hydrocephalus, allowing early intervention and 14
prevention of recurrence.
Starnoni 6
ACCEPTED MANUSCRIPT 9
Settecase et al. reviewed the radiological images of 26 patients with SLSCs to identify the anatomic factors contributing to its pathogenesis. They identified two type of SLSCs; in the first type they reported a herniation into a large pneumatized lateral recess of the sphenoid sinus, becoming symptomatic with CSF leak and headache, the second type was characterized by an encephalocele isolated to the great sphenoid wing without
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involvement of the sphenoid sinus presenting more often with neurological signs. Interestingly they noted that all patients presented sphenoid arachnoid pits noncontiguous with the SLSC, on the same side or contralaterally involving the inner table of the medial greater sphenoid
SC
wing. Altered CSF dynamic and increased hydrostatic pressure and pulsatile forces may lead to the development of these pits in the cranial base and eventually break into the sphenoid 9
sinus in case of a pneumatization of the lateral recesses.
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These findings were also correlated to an extended pneumatization of the lateral recess, reported in 100% of the patients presenting a herniation into the sphenoid sinus, and an 9
empty or partially empty sella, reported in 61% of the patients in the series of Settecase.
The previous cited radiological associations have been largely reported and included as signs of raised intracranial pressure which reinforces the suggestion that CSF flow 9,10,16,17
TE D
dynamics may play a role in the pathogenesis of SLSCs.
We report a unique case in literature to the best of our knowledge of a SLSCs in association with a CMI and reviewed the clinical radiological dossier in order to delineate the
EP
underlying pathological factors contributing to its development. On CT we identified the presence of multiple arachnoid pits along the inner table of the contralateral greater sphenoid
AC C
wing and an extensive pneumatization of the lateral sphenoid recesses associated with a focal dehiscence of the greater wing of the sphenoid bone without any other associated congenital skull base defects (Fig.1). These findings were also associated with an empty sella and bilateral prominent Meckel’s cave(Fig.2). These radiological features support the hypothesis that CSF dynamics disruption and increased intracranial pressure in CMI may have played a major role in the SLSCs development in our patient and identifies this latter as a potential complication of CMI in adult population. A common pathophysiological mechanisms in CMI and SLSCs associated with IIH may also represent a unifying theory
Starnoni 7
ACCEPTED MANUSCRIPT
based on several evidences showing a similar impaired intracranial compliance in both CMI and IIH cohorts of patients.
18
In absence of any other associated skull base defects in our patient, we think that a congenital defect is highly unlikely, especially because mature SS pneumatization is known to 19
occur in later childhood ; Moreover the SLSCs originates lateral to the foramen rotundum,
RI PT
ruling out their correlation with a persistent Sternberg canal which is located under the 20
cavernous sinus.
SLSCs are the least common type of basal encephaloceles and their lateral location
SC
represent a surgical challenge due to the importance of an adequate exposure which is mandatory in performing an adequate skull base defect repair.
Although transcranial and transfacial approaches have been previously described,
21-23
the
M AN U
transpterygoid and transethmoid endoscopic approaches have proved to be an elegant and less invasive method which provides a direct visualization of the lateral region of the sphenoid 24-
sinus with higher success rates than transcranial approaches, without any brain retraction. 27
The importance of a wide exposure and sequential multilayer reconstruction to prevent
TE D
recurrent CSF leaks cannot be overemphasized. The closure of the bony defect is based on the available materials and, as long as the principles of vascular reconstructions are maintained, the different described techniques depend on the familiarity of the surgeon. In
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this context we point out that layers of bio materials and sealants can become a barrier to neovascularization and be counterproductive in the long run.
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The endonasal endoscopic approaches have proved to be more physiological and effective 26,27
technique when compared to the traditional trans cranial approaches.
The patient has consented to submission of this case report to the journal
Starnoni 8
ACCEPTED MANUSCRIPT Bibliography 1.
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2.
Arnautovic A, Splavski B, Boop FA, Arnautovic KI: Pediatric and adult Chiari malformation Type I surgical series 1965-2013: a review of demographics, operative treatment, and outcomes. J Neurosurg Pediatr 15:161-177, 2015 Murphy RL, Tubbs RS, Grabb PA, Oakes WJ: Chiari I malformation and idiopathic growth hormone deficiency in siblings. Childs Nerv Syst 22:632-634, 2006 Tubbs RS, Oakes WJ: Pierre-Robin syndrome associated with Chiari I malformation. Childs Nerv Syst 20:1-2; author reply 5-7, 2004 Tubbs RS, Oakes WJ: Costello syndrome and Chiari I malformation: apropos of a case with a review of the literature regarding a potential association. J Child Neurol 18:496-498, 2003 Tubbs RS, Rutledge SL, Kosentka A, Bartolucci AA, Oakes WJ: Chiari I malformation and neurofibromatosis type 1. Pediatr Neurol 30:278-280, 2004 Tubbs RS, Smyth MD, Oakes WJ: Chiari I malformation and caudal regression syndrome: a previously unreported association. Clin Dysmorphol 12:147-148, 2003 Tubbs RS, Smyth MD, Oakes WJ: Chiari I malformation and cloacal exstrophy: report of a patient with both defects of blastogenesis. Am J Med Genet A 119A:231-233, 2003 Tubbs RS, Smyth MD, Wellons JC, 3rd, Oakes WJ: Hemihypertrophy and the Chiari I malformation. Pediatr Neurosurg 38:258-261, 2003 Settecase F, Harnsberger HR, Michel MA, Chapman P, Glastonbury CM: Spontaneous lateral sphenoid cephaloceles: anatomic factors contributing to pathogenesis and proposed classification. AJNR Am J Neuroradiol 35:784-789, 2014 Bialer OY, Rueda MP, Bruce BB, Newman NJ, Biousse V, Saindane AM: Meningoceles in idiopathic intracranial hypertension. AJR Am J Roentgenol 202:608-613, 2014 Schick B, Brors D, Prescher A: Sternberg's canal--cause of congenital sphenoidal meningocele. Eur Arch Otorhinolaryngol 257:430-432, 2000 Brainard L, Chen DA, Aziz KM, Hillman TA: Association of benign intracranial hypertension and spontaneous encephalocele with cerebrospinal fluid leak. Otol Neurotol 33:1621-1624, 2012 Schlosser RJ, Woodworth BA, Wilensky EM, Grady MS, Bolger WE: Spontaneous cerebrospinal fluid leaks: a variant of benign intracranial hypertension. Ann Otol Rhinol Laryngol 115:495-500, 2006 Carrau RL, Snyderman CH, Kassam AB: The management of cerebrospinal fluid leaks in patients at risk for high-pressure hydrocephalus. Laryngoscope 115:205-212, 2005 Jindal M, Hiam L, Raman A, Rejali D: Idiopathic intracranial hypertension in otolaryngology. Eur Arch Otorhinolaryngol 266:803-806, 2009 Schuknecht B, Simmen D, Briner HR, Holzmann D: Nontraumatic skull base defects with spontaneous CSF rhinorrhea and arachnoid herniation: imaging findings and correlation with endoscopic sinus surgery in 27 patients. AJNR Am J Neuroradiol 29:542-549, 2008
3. 4.
SC
5.
8. 9.
10.
11.
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12.
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7.
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6.
13.
14.
15. 16.
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21.
22.
23.
24.
25.
26.
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27.
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20.
SC
19.
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18.
Shetty PG, Shroff MM, Fatterpekar GM, Sahani DV, Kirtane MV: A retrospective analysis of spontaneous sphenoid sinus fistula: MR and CT findings. AJNR Am J Neuroradiol 21:337-342, 2000 Fric R, Eide PK: Comparative observational study on the clinical presentation, intracranial volume measurements, and intracranial pressure scores in patients with either Chiari malformation Type I or idiopathic intracranial hypertension. J Neurosurg:1-11, 2016 Scuderi AJ, Harnsberger HR, Boyer RS: Pneumatization of the paranasal sinuses: normal features of importance to the accurate interpretation of CT scans and MR images. AJR Am J Roentgenol 160:1101-1104, 1993 Baranano CF, Cure J, Palmer JN, Woodworth BA: Sternberg's canal: fact or fiction? Am J Rhinol Allergy 23:167-171, 2009 Gurkanlar D, Akyuz M, Acikbas C, Ermol C, Tuncer R: Difficulties in treatment of CSF leakage associated with a temporal meningocele. Acta Neurochir (Wien) 149:1239-1242, 2007 Landreneau FE, Mickey B, Coimbra C: Surgical treatment of cerebrospinal fluid fistulae involving lateral extension of the sphenoid sinus. Neurosurgery 42:1101-1104; discussion 1104-1105, 1998 Tsutsumi K, Asano T, Shigeno T, Matsui T, Ito S, Kaizu H: Transcranial approach for transsphenoidal encephalocele: report of two cases. Surg Neurol 51:252-257, 1999 Nyquist GG, Anand VK, Mehra S, Kacker A, Schwartz TH: Endoscopic endonasal repair of anterior skull base non-traumatic cerebrospinal fluid leaks, meningoceles, and encephaloceles. J Neurosurg 113:961-966, 2010 Mirza S, Thaper A, McClelland L, Jones NS: Sinonasal cerebrospinal fluid leaks: management of 97 patients over 10 years. Laryngoscope 115:17741777, 2005 Tabaee A, Anand VK, Cappabianca P, Stamm A, Esposito F, Schwartz TH: Endoscopic management of spontaneous meningoencephalocele of the lateral sphenoid sinus. J Neurosurg 112:1070-1077, 2010 Alexander NS, Chaaban MR, Riley KO, Woodworth BA: Treatment strategies for lateral sphenoid sinus recess cerebrospinal fluid leaks. Arch Otolaryngol Head Neck Surg 138:471-478, 2012
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Fig. 1 MRI evaluation at the time of original presentation of CMI. Axial (A and B) T2W images show lateral sphenoid encephalocele (straight arrow) and the normal ventricular size. Sagittal (C) T1W image shows the caudal displacement of the cerebellar tonsils below the plane of the foramen magnum. Fig. 2 Preoperative coronal CT scan image (A) shows focal bony dehiscence of the lateral wall of the sphenoid sinus (straight arrow) communicating with a large pneumatized lateral
Starnoni 10
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sphenoid recess (*).Coronal CT scan image (B) demonstrates the multiple arachnoid pits in the greater wing of sphenoid on the contralateral side (curved arrow). Fig. 3 Preoperative sagittal (A and B) and axial (C) T2W MRI showing a portion of the right mesial temporal lobe herniating into the right sphenoid sinus. The figure also shows the empty sella (*) and bilateral prominent Meckel’s cave (curved arrows)..
reconstruction of the skull base (temporal fossa) defect.
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Fig. 4 Postoperative axial (A) and sagittal (B) CT scan images showing the bony
Video : Lateral sphenoid encephalocele excision through an endoscopic transpterygoid
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M AN U
SC
approach followed by a multilayer reconstruction of the skull base defect.
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ACCEPTED MANUSCRIPT Highlights
SLSCs occur in the presence of a large pneumatized lateral recess.
•
Raised intracranial pressure may lead to the formation of predisposing anatomical factors.
•
CSF dynamic disruption and increased ICP may be the leading cause of this rare entity.
•
A wide exposure and multilayer reconstruction are mandatory in performing a skull base
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•
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repair.
S1878-8750(16)30969-X
DOI:
10.1016/j.wneu.2016.09.112
Reference:
WNEU 4652
To appear in:
World Neurosurgery
Received Date: 27 April 2016 Revised Date:
22 September 2016
Accepted Date: 26 September 2016
Please cite this article as: Starnoni D, Daniel RT, George M, Messerer M, Unusual association between spontaneous lateral sphenoid encephalocele and Chiari malformation Type I: Endoscopic repair through a transpterygoid approach, World Neurosurgery (2016), doi: 10.1016/j.wneu.2016.09.112. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Starnoni 1
ACCEPTED MANUSCRIPT
Unusual association between spontaneous lateral sphenoid encephalocele and Chiari malformation Type I: Endoscopic repair through a transpterygoid approach
Messerer MD*
RI PT
Daniele Starnoni MD*; Roy Thomas Daniel, MCh*; Mercy George**; Mahmoud
*Neurosurgical Service, Centre Hospitalier Universitaire Vaudois (CHUV); Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
M AN U
University of Lausanne, Lausanne, Switzerland
SC
**ENT Service, Centre Hospitalier Universitaire Vaudois (CHUV); Faculty of Biology and Medicine,
Corresponding author: Daniele Starnoni
Rue du Bugnon 46 CH-1011 Lausanne, Switzerland +41 79 556 87 69
EP
[email protected]
TE D
Service de Neurochirurgie, Centre Hospitalier Universitaire Vaudois (CHUV)
AC C
Conflict of Interest: The authors declare that they have no conflict of interest.
Keywords: chiari malformation Type I, meningoencephalocele, encephalocele, sphenoid sinus, skull base, endoscopic surgery
Abbreviations list: (CMI) Chiari malformation Type I; (CSF) cerebrospinal fluid; (SLSCs) spontaneous lateral sphenoid encephaloceles; (IIH) idiopathic intracranial hypertension
Starnoni 2
ACCEPTED MANUSCRIPT Abstract
Background: Spontaneous meningoencephaloceles of the lateral sphenoid sinus are rare entities and their peculiar location represent a surgical challenge due to the importance of a wide exposure and skull base reconstruction. They are thought to arise from congenital base defect of the lateral sphenoid or in some cases have been postulated to represent a rare manifestation of altered CSF
RI PT
dynamics. We report the first case in literature of a Chiari malformation type I and a lateral sphenoid encephaloceles revising the theoretical etiology and surgical technique of endoscopic repair.
Case Description: A 50 year-old woman, with a surgical history of symptomatic Chiari malformation
SC
type I, presented with episodes of spontaneous CSF rhinorrhea. Radiological investigations revealed a left mesial temporal encephalocele herniating into the lateral recess of the sphenoid sinus and radiological features of altered CSF dynamics which may have played an etiological role. An
M AN U
endoscopic transpterygoid excision of the encephalocele and multilayer skull base repair was performed.
Conclusion: The association of SLSC with Chiari type I is distinctly unusual. Predisposing factors and disruption of CSF dynamics may play a major role in the developing of this rare complication in patients with CMI. Because of its distinct location, transethmoid or transpterygoid endoscopic
TE D
approaches represent an excellent surgical technique to treat these lesions thanks to their wide and direct visualization of the entire skull base defect following the encephalocele excision allowing an
AC C
EP
adequate multilayer repair and lateral sphenoid recess occlusion.
Starnoni 3
ACCEPTED MANUSCRIPT
Chiari malformation Type I (CMI) is a craniocervical junction disorder characterized by caudal displacement of the cerebellar tonsils at least 5 mm below the plane of the foramen magnum into the spinal canal. It may be congenital or acquired, the peak age of presentation 1
is 8 years in the pediatric population and 41 years in adults. The physiopathology of the clinical presentation is characterized by disruption of normal cerebrospinal fluid (CSF) flow
RI PT
and altered CSF dynamics at the level of the foramen magnum leads to isolation of
intracranial compartment causing transient elevations of intracranial pressure which is
commonly associated with cervical syringomyelia, reported in 30-70%, and hydrocephalus in 1
7-9%.
2-8
SC
Numerous associations with CMI have been reported
but a herniation of
intracranial contents through a bony defect (meningocele or meningoencephalocele),
to the best of our knowledge.
M AN U
characteristic of Chiari Type III, in association with a CMI has not been previously described
Non-traumatic encephalocele may be congenital if associated with skull base bony defect and in its absence, it has been hypothesized to represent a rare consequence of chronic intracranial hypertension.
9
TE D
We report a unique case in literature of CMI and a lateral sphenoid encephalocele in a 50 year-old patient. The radiological characteristics in association with the physiopathological hypothesis are reviewed in order to better define this rare association. We
EP
also describe the surgical approach and the skull base reconstruction technique for these
AC C
challenging lesions.
Case Report
A 50 year-old woman was evaluated for a left mesial temporal encephalocele
herniating into the lateral recess of the sphenoid sinus presenting with episodes of spontaneous CSF rhinorrhea. The patient had a previous history of symptomatic CMI and had undergone, seven years before the current admission, a foramen magnum decompression with expansive duroplasty, followed by ventriculoperitoneal shunt placement, 3 months later, for persistent signs and symptoms of intracranial hypertension without ventricular dilation.
Starnoni 4
ACCEPTED MANUSCRIPT
The values of the opening pressure were not reported in her dossier, the magnetic resonance venography report was normal. At the time of our first consultation we reviewed the clinico-radiological dossier of the patient and identified the encephalocele as being present at the same time of the CMI diagnosis (Figure 1). Axial and coronal bone CT images showed multiple ovoid bony defects
RI PT
in the greater wing of the sphenoid bone and a focal bony dehiscence of the lateral wall of the left sphenoid sinus with soft tissue herniating into a large pneumatized lateral sphenoid recess (Figure 2). T1 and T2- weighted sequences demonstrated the contents of the
SC
herniation as an encephalocele. MRI images also showed coexisting empty sella and bilateral prominent Meckel’s cave (Figure 3). The ventricular size was normal with no hydrocephalus and a functional ventriculo-peritoneal shunt.
M AN U
In view of progressive increase in size of the encephalocele on subsequent MRIs it was decided to perform an endoscopic transpterygoid excision of the encephalocele. We performed an anterior and posterior ethmoidectomy with complete middle turbinectomy along with the creation of a mucoperiostial vascularized middle turbinate flap. A transethmoid sphenoidotomy and partial maxillary antrostomy was performed. The mucosa of the posterior
TE D
wall was reflected and the anterior perpendicular process of the palatine bone was dissected and drilled to expose and resect part of the medial plate of pterygoid process allowing a direct visualization of the lateral recess of the sphenoid sinus. The 30-degree angled endoscope
EP
allowed us to clearly visualize the encephalocele in the lateral recess of the sphenoid sinus protruding through a small round bony defect. It was meticulously dissected and excised, care
AC C
was taken to cauterize and reduce the skull encephalocele stump at the skull base. We then performed a multi-layered skull base dural and bony repair. A fascia lata graft and tissue sealant was used for the dural repair followed by osseous reconstruction (middle turbinate bone graft) placed as an on-lay on top of the fascia and sunk into the skull base defect (Figure 3). The mucoperiostial vascularized middle turbinate flap was then used to consolidate and seal the skull base repair. The final reconstruction was further secured by a layer of bioabsorbable artificial dura and free-fat graft followed by the application of a synthetic sealant. The lateral recess was occluded with an autologous fat graft (video).
Starnoni 5
ACCEPTED MANUSCRIPT
The patient had uneventful post-operative course and a three- and six-month followup CT showed no signs of recurrence of the encephalocele and the patient didn’t experience any signs of symptoms of intracranial hypertension confirming the patency of the shunt (Figure 4).
RI PT
Discussion
Meningoencephaloceles can be categorized as congenital in case of a pre-existing skull base defect or associated with trauma, surgery or malignancies. In absence of any
10
meningoencephaloceles.
SC
predisposing factors they are defined as spontaneous and account for less than 9% of all
In the subset of spontaneous encephaloceles the lateral sphenoid
recess represents a very rare location and these meningoencephaloceles are more likely to
M AN U
occur in the presence of a large pneumatization of the lateral recess of the sphenoid sinus; in such cases the herniation can become apparent with a CSF leak and thereby pose a risk for ascending infections.
Many studies have focused on the etiopathology of this spontaneous lateral sphenoid encephaloceles (SLSCs) and initially it was believed to be correlated with a persistent lateral 11
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craniopharyngeal (Sternberg) canal. More recently, radiological and clinical observations of association between SLSCs and intracranial hypertension supports the hypothesis that a CSF dynamic disruption and increased intracranial hypertension may be the leading cause of
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this rare entity. A strong correlation between SLSCs and idiopathic intracranial hypertension (IIH) has been widely reported in many series in almost 70% of the patients
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suggesting
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that, in this peculiar case, the encephalocele repair alone may have a high risk of 14
recurrence. This supposition has also been corroborated by reports of patients presenting signs of increased intracranial pressure after treatment of the encephalocele and skull base repair, suggesting a decompressive role of the encephalocele for alleviating raised 15
intracranial pressure.
In this light Carrau et al. offered an algorithm based on opening
pressure established 3-5 days after the endoscopic repair by means of lumbar puncture in order to identify prospectively occult hydrocephalus, allowing early intervention and 14
prevention of recurrence.
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Settecase et al. reviewed the radiological images of 26 patients with SLSCs to identify the anatomic factors contributing to its pathogenesis. They identified two type of SLSCs; in the first type they reported a herniation into a large pneumatized lateral recess of the sphenoid sinus, becoming symptomatic with CSF leak and headache, the second type was characterized by an encephalocele isolated to the great sphenoid wing without
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involvement of the sphenoid sinus presenting more often with neurological signs. Interestingly they noted that all patients presented sphenoid arachnoid pits noncontiguous with the SLSC, on the same side or contralaterally involving the inner table of the medial greater sphenoid
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wing. Altered CSF dynamic and increased hydrostatic pressure and pulsatile forces may lead to the development of these pits in the cranial base and eventually break into the sphenoid 9
sinus in case of a pneumatization of the lateral recesses.
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These findings were also correlated to an extended pneumatization of the lateral recess, reported in 100% of the patients presenting a herniation into the sphenoid sinus, and an 9
empty or partially empty sella, reported in 61% of the patients in the series of Settecase.
The previous cited radiological associations have been largely reported and included as signs of raised intracranial pressure which reinforces the suggestion that CSF flow 9,10,16,17
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dynamics may play a role in the pathogenesis of SLSCs.
We report a unique case in literature to the best of our knowledge of a SLSCs in association with a CMI and reviewed the clinical radiological dossier in order to delineate the
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underlying pathological factors contributing to its development. On CT we identified the presence of multiple arachnoid pits along the inner table of the contralateral greater sphenoid
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wing and an extensive pneumatization of the lateral sphenoid recesses associated with a focal dehiscence of the greater wing of the sphenoid bone without any other associated congenital skull base defects (Fig.1). These findings were also associated with an empty sella and bilateral prominent Meckel’s cave(Fig.2). These radiological features support the hypothesis that CSF dynamics disruption and increased intracranial pressure in CMI may have played a major role in the SLSCs development in our patient and identifies this latter as a potential complication of CMI in adult population. A common pathophysiological mechanisms in CMI and SLSCs associated with IIH may also represent a unifying theory
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based on several evidences showing a similar impaired intracranial compliance in both CMI and IIH cohorts of patients.
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In absence of any other associated skull base defects in our patient, we think that a congenital defect is highly unlikely, especially because mature SS pneumatization is known to 19
occur in later childhood ; Moreover the SLSCs originates lateral to the foramen rotundum,
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ruling out their correlation with a persistent Sternberg canal which is located under the 20
cavernous sinus.
SLSCs are the least common type of basal encephaloceles and their lateral location
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represent a surgical challenge due to the importance of an adequate exposure which is mandatory in performing an adequate skull base defect repair.
Although transcranial and transfacial approaches have been previously described,
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the
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transpterygoid and transethmoid endoscopic approaches have proved to be an elegant and less invasive method which provides a direct visualization of the lateral region of the sphenoid 24-
sinus with higher success rates than transcranial approaches, without any brain retraction. 27
The importance of a wide exposure and sequential multilayer reconstruction to prevent
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recurrent CSF leaks cannot be overemphasized. The closure of the bony defect is based on the available materials and, as long as the principles of vascular reconstructions are maintained, the different described techniques depend on the familiarity of the surgeon. In
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this context we point out that layers of bio materials and sealants can become a barrier to neovascularization and be counterproductive in the long run.
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The endonasal endoscopic approaches have proved to be more physiological and effective 26,27
technique when compared to the traditional trans cranial approaches.
The patient has consented to submission of this case report to the journal
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ACCEPTED MANUSCRIPT Bibliography 1.
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Arnautovic A, Splavski B, Boop FA, Arnautovic KI: Pediatric and adult Chiari malformation Type I surgical series 1965-2013: a review of demographics, operative treatment, and outcomes. J Neurosurg Pediatr 15:161-177, 2015 Murphy RL, Tubbs RS, Grabb PA, Oakes WJ: Chiari I malformation and idiopathic growth hormone deficiency in siblings. Childs Nerv Syst 22:632-634, 2006 Tubbs RS, Oakes WJ: Pierre-Robin syndrome associated with Chiari I malformation. Childs Nerv Syst 20:1-2; author reply 5-7, 2004 Tubbs RS, Oakes WJ: Costello syndrome and Chiari I malformation: apropos of a case with a review of the literature regarding a potential association. J Child Neurol 18:496-498, 2003 Tubbs RS, Rutledge SL, Kosentka A, Bartolucci AA, Oakes WJ: Chiari I malformation and neurofibromatosis type 1. Pediatr Neurol 30:278-280, 2004 Tubbs RS, Smyth MD, Oakes WJ: Chiari I malformation and caudal regression syndrome: a previously unreported association. Clin Dysmorphol 12:147-148, 2003 Tubbs RS, Smyth MD, Oakes WJ: Chiari I malformation and cloacal exstrophy: report of a patient with both defects of blastogenesis. Am J Med Genet A 119A:231-233, 2003 Tubbs RS, Smyth MD, Wellons JC, 3rd, Oakes WJ: Hemihypertrophy and the Chiari I malformation. Pediatr Neurosurg 38:258-261, 2003 Settecase F, Harnsberger HR, Michel MA, Chapman P, Glastonbury CM: Spontaneous lateral sphenoid cephaloceles: anatomic factors contributing to pathogenesis and proposed classification. AJNR Am J Neuroradiol 35:784-789, 2014 Bialer OY, Rueda MP, Bruce BB, Newman NJ, Biousse V, Saindane AM: Meningoceles in idiopathic intracranial hypertension. AJR Am J Roentgenol 202:608-613, 2014 Schick B, Brors D, Prescher A: Sternberg's canal--cause of congenital sphenoidal meningocele. Eur Arch Otorhinolaryngol 257:430-432, 2000 Brainard L, Chen DA, Aziz KM, Hillman TA: Association of benign intracranial hypertension and spontaneous encephalocele with cerebrospinal fluid leak. Otol Neurotol 33:1621-1624, 2012 Schlosser RJ, Woodworth BA, Wilensky EM, Grady MS, Bolger WE: Spontaneous cerebrospinal fluid leaks: a variant of benign intracranial hypertension. Ann Otol Rhinol Laryngol 115:495-500, 2006 Carrau RL, Snyderman CH, Kassam AB: The management of cerebrospinal fluid leaks in patients at risk for high-pressure hydrocephalus. Laryngoscope 115:205-212, 2005 Jindal M, Hiam L, Raman A, Rejali D: Idiopathic intracranial hypertension in otolaryngology. Eur Arch Otorhinolaryngol 266:803-806, 2009 Schuknecht B, Simmen D, Briner HR, Holzmann D: Nontraumatic skull base defects with spontaneous CSF rhinorrhea and arachnoid herniation: imaging findings and correlation with endoscopic sinus surgery in 27 patients. AJNR Am J Neuroradiol 29:542-549, 2008
3. 4.
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8. 9.
10.
11.
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12.
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6.
13.
14.
15. 16.
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21.
22.
23.
24.
25.
26.
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27.
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20.
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19.
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18.
Shetty PG, Shroff MM, Fatterpekar GM, Sahani DV, Kirtane MV: A retrospective analysis of spontaneous sphenoid sinus fistula: MR and CT findings. AJNR Am J Neuroradiol 21:337-342, 2000 Fric R, Eide PK: Comparative observational study on the clinical presentation, intracranial volume measurements, and intracranial pressure scores in patients with either Chiari malformation Type I or idiopathic intracranial hypertension. J Neurosurg:1-11, 2016 Scuderi AJ, Harnsberger HR, Boyer RS: Pneumatization of the paranasal sinuses: normal features of importance to the accurate interpretation of CT scans and MR images. AJR Am J Roentgenol 160:1101-1104, 1993 Baranano CF, Cure J, Palmer JN, Woodworth BA: Sternberg's canal: fact or fiction? Am J Rhinol Allergy 23:167-171, 2009 Gurkanlar D, Akyuz M, Acikbas C, Ermol C, Tuncer R: Difficulties in treatment of CSF leakage associated with a temporal meningocele. Acta Neurochir (Wien) 149:1239-1242, 2007 Landreneau FE, Mickey B, Coimbra C: Surgical treatment of cerebrospinal fluid fistulae involving lateral extension of the sphenoid sinus. Neurosurgery 42:1101-1104; discussion 1104-1105, 1998 Tsutsumi K, Asano T, Shigeno T, Matsui T, Ito S, Kaizu H: Transcranial approach for transsphenoidal encephalocele: report of two cases. Surg Neurol 51:252-257, 1999 Nyquist GG, Anand VK, Mehra S, Kacker A, Schwartz TH: Endoscopic endonasal repair of anterior skull base non-traumatic cerebrospinal fluid leaks, meningoceles, and encephaloceles. J Neurosurg 113:961-966, 2010 Mirza S, Thaper A, McClelland L, Jones NS: Sinonasal cerebrospinal fluid leaks: management of 97 patients over 10 years. Laryngoscope 115:17741777, 2005 Tabaee A, Anand VK, Cappabianca P, Stamm A, Esposito F, Schwartz TH: Endoscopic management of spontaneous meningoencephalocele of the lateral sphenoid sinus. J Neurosurg 112:1070-1077, 2010 Alexander NS, Chaaban MR, Riley KO, Woodworth BA: Treatment strategies for lateral sphenoid sinus recess cerebrospinal fluid leaks. Arch Otolaryngol Head Neck Surg 138:471-478, 2012
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Fig. 1 MRI evaluation at the time of original presentation of CMI. Axial (A and B) T2W images show lateral sphenoid encephalocele (straight arrow) and the normal ventricular size. Sagittal (C) T1W image shows the caudal displacement of the cerebellar tonsils below the plane of the foramen magnum. Fig. 2 Preoperative coronal CT scan image (A) shows focal bony dehiscence of the lateral wall of the sphenoid sinus (straight arrow) communicating with a large pneumatized lateral
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sphenoid recess (*).Coronal CT scan image (B) demonstrates the multiple arachnoid pits in the greater wing of sphenoid on the contralateral side (curved arrow). Fig. 3 Preoperative sagittal (A and B) and axial (C) T2W MRI showing a portion of the right mesial temporal lobe herniating into the right sphenoid sinus. The figure also shows the empty sella (*) and bilateral prominent Meckel’s cave (curved arrows)..
reconstruction of the skull base (temporal fossa) defect.
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Fig. 4 Postoperative axial (A) and sagittal (B) CT scan images showing the bony
Video : Lateral sphenoid encephalocele excision through an endoscopic transpterygoid
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approach followed by a multilayer reconstruction of the skull base defect.
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ACCEPTED MANUSCRIPT Highlights
SLSCs occur in the presence of a large pneumatized lateral recess.
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Raised intracranial pressure may lead to the formation of predisposing anatomical factors.
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CSF dynamic disruption and increased ICP may be the leading cause of this rare entity.
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A wide exposure and multilayer reconstruction are mandatory in performing a skull base
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repair.