Operative management of idiopathic spinal intradural arachnoid cysts ...

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Dec 9, 2012 - Abstract. Background Spinal intradural arachnoid cysts are rare with only a few patients reported so far. Idiopathic, traumatic, posthemorrhagic ...
Childs Nerv Syst (2013) 29:657–664 DOI 10.1007/s00381-012-1990-7

ORIGINAL PAPER

Operative management of idiopathic spinal intradural arachnoid cysts in children: a systematic review Petros Evangelou & Jürgen Meixensberger & Matthias Bernhard & Wolfgang Hirsch & Wieland Kiess & Andreas Merkenschlager & Ulf Nestler & Matthias Preuss

Received: 20 October 2012 / Accepted: 26 November 2012 / Published online: 9 December 2012 # Springer-Verlag Berlin Heidelberg 2012

Abstract Background Spinal intradural arachnoid cysts are rare with only a few patients reported so far. Idiopathic, traumatic, posthemorrhagic, and postinflammatory causes have been reported in the literature. Especially, idiopathic lesions, in which other possible etiological factors have been ruled out, seem to be rare. Patients and Methods We systematically reviewed the literature in regards to localization within the spinal canal, treatment options, complications, and outcome. Additionally, we present management strategies in two progressively symptomatic children less than 3 years of age with idiopathic intradural arachnoid cysts. Results In total, 21 pediatric cases including the presented cases have been analyzed. Anterior idiopathic spinal arachnoid cysts are predominantly located in the cervical spine in 87.5 % of all cases, whereas posterior cysts can be found at thoracic and thoracolumbar segments in 84.6 % of the patients. Most children presented with motor deficits (76.2 %). Twenty-five percent of anterior spinal arachnoid cysts caused back pain as the only presenting symptom. Open P. Evangelou : J. Meixensberger : U. Nestler : M. Preuss (*) Department of Neurosurgery, Pediatric Neurosurgery, University Hospital Leipzig, Liebigstrasse 20, 04103 Leipzig, Germany e-mail: [email protected] M. Bernhard : A. Merkenschlager Division of Neuropediatrics, University Hospital Leipzig, Leipzig, Germany W. Hirsch Division of Pediatric Radiology, University Hospital Leipzig, Leipzig, Germany W. Kiess Department of Children’s and Adolescence Health, University Hospital Leipzig, Leipzig, Germany

fenestration by a dorsal approach has been used in the vast majority of cases. No major surgical complications have been reported. Ninety-four percent of all patients did improve or showed no neurological deficits. Recurrence rate after successful surgical treatment was low (9.5 %). Conclusion Idiopathic spinal intradural arachnoid cysts can present with neurological deficits in children. Pathologies are predominantly located in the cervical spine anteriorly and in thoracic and thoracolumbar segments posteriorly to the spinal cord. In symptomatic cases, microsurgical excision and cyst wall fenestration via laminotomy are recommended. Our radiological, intraoperative, and pathological findings support the cerebrospinal fluid obstruction and vent mechanism theory of arachnoid cysts. Keywords Idiopathic spinal arachnoid cyst . Intradural arachnoid cyst . Spinal CSF circulation obstruction

Introduction Congenital spinal intradural arachnoid cysts are a welldescribed, yet very uncommon entity that can be treated successfully by open fenestration in the majority of cases [1, 2, 19]. According to Richaud, intradural arachnoid cysts are classified as type III meningeal cysts [25]. Treatment options include limited laminoplasty and endoscopeassisted fenestration and cyst wall removal [4, 17]. Many patients seem to become symptomatic and require treatment due to progressive neurological deficits. In the literature, only small series of patients and case reports are found, often mixing adult and pediatric patients and with a variety of underlying conditions as causes of the arachnoid cysts. Thus, an attempt to systematically review the pediatric cases reported so far is made in order to obtain data on occurrence, complications, and prognosis. Management

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strategies, pre- and postoperative assessments, and followup results are also presented.

marked separately and were not included in the analysis. Descriptive statistical analysis was performed on the collected data.

Patients and methods

Case 1

Patients

A 23-month-old boy presented with delayed motor development and slowly progressive lower limb spasticity resulting in gait disturbances and paraparesis predominantly on the left side with pes equinus position bilaterally. The upper limbs remained unaffected. Except for minor, asymptomatic left-sided subarachnoid hemorrhage in the posterior fossa under delivery, no further history of trauma, infections, or spinal hemorrhage was present. An arachnoid cyst at levels T1–3 was diagnosed by MRI at the time of delivery. It was concluded that arachnoid cyst has not been caused by the birth trauma. Furthermore, a mild Chiari type I malformation was detected. The arachnoid cyst at thoracic spine levels T1–3 did not show any significant progress over the period of 3 years (Fig. 1a, b). However, the spinal cord was displaced ventrally suggesting a cerebrospinal fluid (CSF) flow disturbance and pressure gradient between the cerebrospinal fluid space and the cyst (Fig. 2a). Examinations of mSEP and t-SEP confirmed the level of spinal cord dysfunction below C6. The boy underwent a bisegmental laminoplasty of T2–3 and microsurgical cyst wall removal of the upper arachnoid wall and fenestration of the lower portions. Intraoperatively, typical arachnoid adhesions at the dorsal surface of the spinal cord were found, partially removed, and fenestrated. The histopathological examination confirmed an arachnoid cyst without signs of inflammation or malignancy. Postoperatively, the boy showed gradual marked reduction of spasticity, foot paresis, gait disturbance, and improved neurological development. Follow-up MRI 6 months postoperatively demonstrated a normal position of the spinal cord without any cyst remnants, restored CSF circulation within the spinal canal (Figs. 1c and 2b).

During the past 3 years at our institution, one male patient aged 23 months and one female patient aged 16 months have been diagnosed with idiopathic spinal intradural arachnoid cysts due to progressive motor dysfunction and delayed motor development. Preoperative radiological assessment was performed using spinal and cranial magnetic resonance imaging (MRI) in T1 and T2, constructive interference steady state (CISS), and contrast-enhanced sequences to rule out tethered cord syndrome, syringomyelia, or other conditions. Neurological assessment included median and tibial nerve somatosensory-evoked potentials (m-SEP and t-SEP) and brainstem acoustic-evoked potentials. Surgical interventions were performed as bisegmental laminoplasties and microsurgical adhesionolysis including circumference inspection of the spinal cord, resection of arachnoid membranes, as well as fenestration of cranial and caudal membranes. Intraoperative SEP monitoring was employed. Laminoplasty was reconstructed using reabsorbable PDS sutures. A minimum of 24-h postoperative bed rest in supine position was employed in the Pediatric Intensive Care Unit. Postoperative follow-up examinations were performed in our neurosurgicalneuropediatric outpatient clinic. Follow-up MRI has been carried out postoperatively at 3 and 12 months including electrophysiological examination of SEPs. Literature search We searched the Med-Line database PubMed with the keywords “spinal intradural arachnoid cyst” and “child.” A second search was performed using the keyword combination of “spinal arachnoid cyst” without child as well as “arachnoid cyst.” All resulting hits were reviewed as far as possible in terms of age at time of diagnosis, gender, location of cyst, neurological status pre- and postoperatively, complications, recurrence, and treatment modalities. Patients with associated neural tube malformations like meningomyeloceles, scoliosis, or other underlying conditions like preceding trauma or infection have been excluded. Maximum age at time of diagnosis was ≤18 years. Having reviewed the publications in regards of relevance and excluded off-topic hits, the resulting reports were analyzed to collect the data of individual cases as detailed as possible. Secondary references within the articles were additionally searched for relevance and included in the review process if found appropriate. Articles with insufficient data have been

Case 2 A 16-month-old girl presented with progressive, therapyresistant delayed motor development of the lower limbs, spasticity predominantly of the left food, and ataxia. No history of trauma, infection, or hemorrhage was present. Cranial and spinal MRIs ruled out other pathologies but disclosed a posterior extramedullary intradural arachnoid cyst with spinal cord compression and CSF circulation disturbance at level T2–4 (Figs. 1d, e and 2c), suggesting a CSF pressure gradient between the CSF space and cystic structure. t-SEP demonstrated a left-sided latency delay and amplitude reduction and near-normal potentials on the right side. Bisegmental laminoplasty at levels T3–4 and removal of cyst walls and fenestration of cranial and caudal borders were performed.

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Fig. 1 Pre- and postoperative MR imaging (a–c case 1, d–f case 2). a, b Preoperative axial CISS sequences showing the arachnoid cyst (arrow) with signs of spinal cord compression of a 3-year-old boy. c Axial T2 sequence, 3 months postoperatively. d, e Preoperative axial

CISS and T2 sequences, respectively, of a 16-month-old girl, showing an intradural extramedullary arachnoid cyst with spinal cord compression (dotted arrow). f Axial T2 sequence 2 months postoperatively

Postoperative neurological examinations confirmed a rapidly improved motor function, reduction of the gait disturbances, and the spasticity within days. The spasticity in the feet showed a further improvement under intensive physiotherapy. Postoperative MRI 2 months after intervention demonstrated restored CSF circulation at the dorsal aspects of the spinal canal and diminished cord compression (Figs. 1f and 2d).

doubtful radiological features [27]. Furthermore, in this review, all but two patients had neural tube defects, namely, myelomeningoceles, or syringomyelia as underlying or associated conditions. All other indexed reports in the keyword search did not match the topic or described association with neural tube defects, scoliosis, or genetic disorders like, e.g., Noonan’s Syndrome [9], or addressed technical or radiological aspects. Many reports demonstrated the association of symptomatic intradural arachnoid cysts with trauma [11, 16, 18]. Additionally, neural tube defects proved to have an association with intradural arachnoid cysts [5, 9, 23]. To our knowledge, an association of intradural spinal cysts with Chiari type I malformation has not been described yet. One report of Jean et al. demonstrated three cases of children presenting with ventrally located arachnoid cysts that developed secondarily after repeated posterior fossa decompression of Chiari type II malformations [12]. A total amount of 19 idiopathic pediatric cases was extracted out of all reports and reviews found in the database besides the present cases of this study (n021). The earliest report of an idiopathic pediatric patient dated back to 1974. Gender distribution showed no significant difference (11 males and 10 females). Mean age at time of treatment was 6.3 years (SD 14.5). An overview of all cases is given in Table 1. About 76.2 % (16 cases) of children presented with

Results of literature research Medline search using keywords spinal intradural arachnoid cyst and child revealed 35 reports. The first report dated back to 1974 by Palmer [20]. Secondary search within the references of the found reports disclosed a report from 1903 by Spiller et al. to be the earliest documentation of an arachnoid cysts and its surgical management [28]. Secondary Medline search found 665 articles for the beforementioned keywords. The majority of the literature found, however, reported extradural cyst or diverticula and adult cases. Out of all the publications found, ten case reports [3, 4, 6–8, 10, 13, 20, 21, 24, 25, 29], one review of two relevant cases [15], one report of dysraphic cases containing two patients without dysraphism [23], and one report with a review of the literature and three own patients [16] matched the selection criteria. However, the latter was criticized for

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Fig. 2 T2-weighted sagittal MR sequences of the reported cases (a, b case 1 pre- and postoperative, respectively; c, d case 2 pre- and postoperative, respectively). Arrow and dotted arrow indicate the arachnoid cysts

motor deficits as predominant symptom. Depending of the affected spinal cord level, mild para- or tetraparesis and gait disturbances occurred. Back pain was an isolated symptom in 25 % of anterior arachnoidal cysts (14.3 % of all cases). In the vast majority of the cases (85.7 %), the diagnosis was made with an MRI of the spine. Other diagnostic modalities used include the CT myelography (19 %) and conventional myelography (23.8 %). In the earlier reports, the use of CSF

examination or CSF-Space manometry was also mentioned. Thirteen cases suffered from a posterior arachnoid cyst, with 11 cases (84.6 %) involving the thoracic spine (seven confined in the thoracic spine, one at the cervical-thoracic junction, and two at the thoracic/lumbar junction), one posterior cervical cyst at C3–6, and one very large cyst extending from C7 to L3. Vice versa, anterior localization of such entities affected in seven out of eight cases (87.5 %) the

1, 5 F

3 11

Chern [4]

Endo [6] Fortuna [30]

M F M M

15

10

2 2, 5 12 9

3

8 F 4, 5 M 9 F

13

3

Kazan [32]

Kumar [15]

Lee [16]

Palmer [20, 21]

Rabb [24]

Takahashi [29]

Present study

Shih [33]

F

9

Jensen [31]

T1–3 T2–4

1, 3 F

C1–3

T1–5 T1–3 C6–T2

C2–4

C3–6 L5–S1 C6–T2 C5–T1

T4–6

C2–3

M

M

M

M

M

Posterior

Posterior

Anterior

Posterior Posterior Anterior

Anterior

Posterior Posterior Posterior Anterior

Posterior

Anterior

Posterior

T11–L3 Posterior

8

Gul [10] T9–L1

Anterior

C0–7

M

Anterior

L1–S1

Gelabert-Gonzales 0, 5 F [7] Gezici [8] 2, 5 M

Posterior Posterior

C7–L3 T6–8

Posterior

Anterior

Back pain

Presenting symptoms

Paraparesis

Mild spastic paraparesis, back pain, nocturnal enuresis Tetraparesis

Paraparesis, hypoesthesia

Tetraparesis

No deficit Spastic paraparesis, hypoesthesia in the right lower limb Paraparesis

MRI

MRI, CT myelography MRI

Spastic paraparesis

Paraparesis

Neck pain

Paraparesis Paraparesis Paraplegia Spastic paraparesis, neurogenic bladder, hypoesthesia (pinprick, light touch, temperature) below T2 Myelography Tetraplegia, respiratory failure Myelography, MRI Recurrent bladder Myelography, MRI Asymptomatic CT myelography, MRI Paraparesis

MRI MRI MRI MRI

MRI, CT myelography MRI

Myelography

MRI

MRI

MRI

MRI CSF manometry, myelography

MRI, CT myelography Paraparesis

MRI

Localization Diagnostics (anterior/ posterior)

F F

T6–9

C6–7

5

Anan [3]

F

Age Gender Spinal level

Author

Table 1 Overview of the reported idiopathic intradural arachnoid cysts in children

Better

Better/II

Better/II

Better/I

Death

Better/II Better/I Better/II Better

Better/III



Unknown/no Unknown/no Unknown/yes, reOP Residual urinary disturbance/no

Unknown/no

At 5-year recurrence, >reOP + shunt (cyst/ atrial) None/no

None/no

Bladder/no

None/no

9

Better/I

Better/II

Better/I

No/no

Spasticity/no

None/no

Unknown Better/I None/no Unknown Unchanged/I None/no 1 Better/I None/no

1

18 24 60 6

6

None/no

None/no

FU deficit/ recurrence

Unchanged/I None/no Better Slight paraparesis/no

Better/I

Better/I

Unknown Better/I

80

1

6

1

142 24

24

40

Follow-up Outcome/ (months) McCormick

Fenestration via laminoplasty 10 T2–3 Laminoplasty and Fenestration 3 T3–4

Fenestration Fenestration Fenestration via laminectomy C6–T2 Percutaneous aspiration

Fenestration, puncture

Fenestration via laminotomy Fenestration Fenestration via laminotomy Laminectomy C5–6 and excision

Fenestration via laminotomy

Fenestration via laminectomy

Fenestration via laminotomy L2 Fenestration via C3–4 laminectomy Delivery via L1-l aminoplasty Fenestration-partial removal

Removal via C6–7 laminoplasty Endoscopic fenestration T6–9 Fenestration two levels Partial removal

Treatment

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cervical spine. Generally, there seems to be a predominance of anterior localization for symptomatic cervical arachnoid cysts and a posterior predominance for the thoracic localization. Open microsurgical fenestration appears to be the treatment of choice (76.5 %); however, there has been one report of successful percutaneous needle aspiration under MR guidance [29]. Surgery appeared to have a low incidence of recurrence after incomplete fenestration (12.5 %) over an average follow-up period of 29.5 months (range 1– 142 months). No major complications have been reported, and neurological deficits improved (or did not occur in the initial asymptomatic cases) in 94 % of the cases. One case report by Palmer in 1974, however, reported a death due to respiratory failure after an unsuccessful fenestration and repeated aspirations of a recurrent high cervical anterior arachnoid cyst [20]. McCormick outcome grades I and II was achieved in 17 cases (89 %), with grade I in 61 % and grade II in 28 % of the cases. No additional neurological deficits have been reported postoperatively.

Discussion The earliest description of an intradural cyst compressing the spinal cord and treated successfully by surgery dates back to 1903 by Spiller [28] and Skoog in 1915 [26]. Idiopathic arachnoid cysts seemed to be first reported by Palmer in 1974, with signs of respiratory failure in a 3-yearold boy. The patient succumbed to the disease of a C2–4 arachnoid cyst after laminectomy and repeated fine-needle aspiration which all had been without permanent effect [20]. In 1978, Duncan and Hoare reviewed five cases of intraspinal arachnoid cysts and considered them congenital [5]. In 1982, a larger series of adult patients were published supporting the congenital origin of the disease [1]. The symptoms of spinal arachnoid cysts, depending on their level of location, comprise of progressive myelopathy or radiculopathy. Sometimes, a rapid deterioration is reported to occur [2, 19, 21, 23, 25]. Often, a minor trauma seems to trigger a clinical decompensation and neurological worsening of an otherwise asymptomatic lesion [16, 18]. Many reports date back to a time prior to MR diagnostics and used myelography as a gold standard in the diagnosis and follow-up of such cysts [1, 5, 15, 19]. Today, even though studies comparing the various methodologies are lacking, it seems to be appropriate to use MRI with CISS sequence technology to gain highresolution information of the cyst extensions and use myelographic techniques only complementary in selected complicated cases [22, 27]. It is generally agreed upon in all reports of pediatric as well as adult cases that the surgical fenestration is the treatment of choice with favorable outcome and low recurrence rates [1, 19, 22]. Arachnoid adhesions and radiological tethered cords are commonly known causes for Chiari

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malformations, besides neural tube defects. However, the signs and symptoms usually comprise of disturbances associated with hindbrain and tonsillar herniation, syringomyelia, or scoliosis. The cases presented in this report show that focal dorsal arachnoid adhesions or cysts resulting in CSF pathway disturbances at the cervicothoracic level can lead to neurological impairment. Adhesions may also disturb the posterior fossa development and result in the formation of a Chiari type malformation as demonstrated in one patient. It is unlikely to assume that Chiari malformations lead to arachnoid cysts in the spine as there has been no such entity reported so far in the literature. Our cases support Kuhlendahl’s theory of CSF trapping in arachnoid adhesion at the caudal end of the arachnoid cyst in a vent-like mechanism [14]. Pulsatile flow into the arachnoid trabeculae or pseudocyst in a craniocaudal direction may lead to a gradually downward displacement of the neural structures at the level of the foramen magnum by a persistent pressure gradient. Vent-like CSF flow obstruction within the spinal canal caused by the arachnoid trabeculae can be asymptomatic for many years. Inflammatory responses (meningitis, etc.) or even mild trauma, posthemorrhagic, or postinflammatory scarring within the arachnoid could lead to a positive CSF net flow into the pseudocyst, resulting in a progressive, sometimes rapid enlargement. This could lead to a dramatic deterioration of the neurological function as reported in many cases after sustaining mild or even minor trauma [15]. It could be therefore assumed that many of the intradural cysts of the spinal canal are not true congenital cysts, but arachnoid adhesions that transform into pseudocystic vent mechanisms and become symptomatic after an external trigger of arachnoid proliferation or formation of adhesions result in CSF outflow obstruction. This is being confirmed by the intraoperative findings of a multitude of arachnoid layers and adhesions whose fenestration and destruction seem to be sufficient to treat the condition. According to this assumption, one might presume that there are no true arachnoid cysts of congenital genesis as their histopathological findings are congruent with those of older patients, but that the trigger of arachnoid CSF flow obstruction occurs during pregnancy or delivery and remains occult, presumably until the occurrence of the before-mentioned initiating factor. Only Gul et al. reported an intact true cyst that had been removed by “spontaneous delivery” in toto, and that could be the solitary case of a true congenital cystic formation [10]. According to our experience, in adult cases as well, no real cystic structure but extensive arachnoid trabeculae and thickened membranes of milky appearance in which CSF is trapped with higher pressure than in the surrounding CSF space can be found [1]. Therefore, a caudal fenestration of the arachnoid cyst wall is crucial to restore the CSF net flow

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through the cyst, resulting in a progressive normalization of the neurological symptoms. The management of idiopathic spinal intradural arachnoid cysts depends on the neurological examination, the imaging data, and the electrophysiological parameters. It is the opinion of the authors that as soon as progressive or therapy-resistant neurological deficits present and are being proven by SEP examination, these patients suffering from an idiopathic intradural arachnoid cyst should be treated by fenestration using microsurgical resection of the arachnoid membranes in the technique described above. Especially in very young children, laminoplasty should be preferred to avoid growth complications. No major procedure-related complications occurred in our patients nor have been reported in the literature. Thus, open microsurgical fenestration seems to be a safe, effective, and definite treatment for even very young patients. In light of the low complication rate, any patient suffering from neurological deficits that can be deducted from the presence of an idiopathic intradural spinal arachnoid cyst should be advised to be treated surgically, when conservative treatment does not provide complete relief from neurological symptoms. The management via fenestration can offer improved motor development to avoid life-long neurological impairment in 89 % of the cases. Postoperative MRI is recommended 2–3 months after surgery to prove sufficient restoration of CSF flow in the dorsal aspects of the spinal canal, diminished cord compression, and elimination of ventral displacement. Furthermore, annual follow-up MRIs are suggested to rule out recurrences and procedure-related complications like growth disturbances and secondary spinal deformities. The recurrence rate based on the available data is 5.3 %.

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