Cervical myelocystocele: Case report and review of literature.

Dysraphisms involving cervical region are very rare and there are very few series describing their follow-up in literature. Here, we report a 6-year-old boy who underwent postnatal "cosmetic" repair of posterior cervical cystic lesion and presented to us with a large recurrence with syringohydromyelia and tethering. Tethered cord should be suspected in the presence of meningocele and intact neurology. Treatment protocols of such complicated cervical spinal dysraphisms should include intradural exploration and detethering, with an aim to prevent neurological deterioration in future.

Introduction

Cervical myelomeningoceles (cMMCs) and meningoceles account for 1–5% of all neural tube defects.[1] They have been published as isolated case reports in literature and very little is known about their follow-up. There are very few articles published in the literature, dealing with follow-up of cMMC.[2-5] Here, we report a case of cervical meningocele in an asymptomatic patient who was detected to have myelocystocele with tethering on imaging and was surgically treated.

Case Report

A 6-year-old boy presented to us with the history of swelling in the posterior cervical region. Past history revealed a “cosmetic” repair of similar swelling at the age of 3 days. On examination, he had a large midline posterior cervical swelling measuring 6 · 5 · 4 cm. The swelling was oval shaped, cystic with a wide sessile base and covered with full-thickness skin bearing scar of the previous surgery [Figure 1]. On examination, growth parameters, developmental assessment and neurological findings were normal. Magnetic resonance imaging (MRI) of the cervical spine revealed a fluid-filled cyst in the subcutaneous tissue of posterior neck consistent with meningocele. There was a communication seen between the meningocele and the cord through a spina bifida at sixth cervical vertebral level. The meningocele was associated with a syrinx just in front of the communication [Figure 2]. There was evidence of a second cyst within this meningocele consistent with myelocystocele [Figure 3]. There was no evidence of hydrocephalus, craniovertebral junction anomalies or dysraphism in other part of the spine. The patient was taken up for surgery. Through a linear incision, the meningocele was defined. The sac was transected and another sac was found within this, which on exploration was attached to cord. Detethering was done. The patient recovered and is doing well.

Figure 1

Clinical photograph showing cervical myelocystocele

Figure 2

MRI T1W image showing myelocystocele with syrinx and communication (arrow)

Figure 3

MRI T1W image showing a cyst within a cyst (arrow head), typical of myelocystocele

Discussion

Cervical myelomeningocoele is a rare condition, accounting for 1–5% of all neural tube defects.[1] The mention of cMMC in literature is in terms of case reports or short series. There are very few series dealing with the follow-up of these patients.[2-5]

Classification and nomenclature of cystic cervical lesions is a controversial topic and various authors have suggested different classifications. The earlier terms used to describe cMMCs included syringoceles[6] and syringomyeloceles.[7] Maclone et al. defined cMMC as closed spinal dysraphism characterized by skin-covered posterior midline mass, a narrow posterior spina bifida and cerebrospinal fluid-filled cyst.[8] Steinbok et al. in the early 1900s proposed the hypothesis of limited dorsal myelochisis and divided cMMCs as meningoceles and myelocystoceles.[9] Pang et al. proposed a classification system based on the internal structure of the cystic lesions, dividing them into limited dorsal myelochisis containing fibroneurovascular stalk in a dural sac and split cord malformations containing two hemicords in a dural sac.[3] Salomao et al. divided these into 1) cystic spinal dysraphism of the cervical and upper thoracic region with a stalk of neuroglial or fibrovascular tissue, 2) myelocystoceles consisting of a second ependymal-lined cyst herniated inside a meningocele and 3) cystic spinal dysraphism of the cervical and upper thoracic region without a stalk or true meningocele.[2] Habibi et al. and Rossi et al. classified cervical myelomeningoceles into two sub groups: fibroneurovascular stalks and myelocystoceles.[510] Our case report adheres to the definition given by Maclone et al. and with respect to other classifications it can be called as limited dorsal myelochisis, myelocystocele and cyst herniation within meningocele. Patients with cMMC differ from those with thoracolumbar and lumbosacral meningomyeloceles.[3] Neurologically a patient with cMMC is well preserved when compared to those with thoracolumbar or lumbosacral myelomeningocele.[11] The concept of tethering in cMMCs has not received much attention because of their rarity and very slight ascent of cervical cord during growth. However, several case reports have documented tethering in cMMCs which presents as neurological deterioration in the future.[12-14] The role of imaging in asymptomatic cervical spinal dysraphisms has been emphasized in literature.[31516] Magnetic resonance imaging is the modality of choice in these lesions, which helps to distinguish the subtypes of cMMC[15] and to identify the associated anomalies of central nervous system like hydrocephalus, split cord malformations, tethering, syringomyelia and chiari malformations.[16] Surgical exploration of these lesions should be aimed at preventing infection, achieving cosmesis and most importantly releasing the tethered cord.[5] Simple excision of meningocele sac and transection of the communication can provide a cosmetic repair but cannot prevent neurological deterioration due to tethering.[34] Neurological deterioration in patients undergoing cosmetic repair without detethering has been well documented, which made re-exploration and excision of tethering structures necessary.[39] Thus, resection of the lesion without detethering is insufficient and surgery of these lesions should include intradural exploration and detethering, with an aim to prevent neurological deterioration in the future.