Congenital Intradural Pathology

Congenital spinal dermal tract: how accurate is clinical and radiological evaluation?

OBJECT A dermal sinus tract is a common form of occult spinal dysraphism. The presumed etiology relates to a focal failure of disjunction resulting in a persistent adhesion between the neural and cutaneous ectoderm. Clinical and radiological features can appear innocuous, leading to delayed diagnosis and failure to appreciate the implications or extent of the abnormality. If it is left untreated, complications can include meningitis, spinal abscess, and inclusion cyst formation. The authors present their experience in 74 pediatric cases of spinal dermal tract in an attempt to identify which clinical and radiological factors are associated with an infective presentation and to assess the reliability of MRI in evaluating this entity. METHODS Consecutive cases of spinal dermal tract treated with resection between 1998 and 2010 were identified from the departmental surgical database. Demographics, clinical history, and radiological and operative findings were collected from the patient records. The presence or absence of active infection (abscess, meningitis) at the time of neurosurgical presentation and any history of local sinus discharge or infection was assessed. Magnetic resonance images were reviewed to evaluate the extent of the sinus tract and determine the presence of an inclusion cyst. Radiological and operative findings were compared. RESULTS The surgical course was uncomplicated in 90% of 74 cases eligible for analysis. Magnetic resonance imaging underreported the presence of both an intradural tract (MRI 46%, operative finding 86%) and an intraspinal inclusion cyst (MRI 15%, operative finding 24%). A history of sinus discharge (OR 12.8, p = 0.0003) and the intraoperative identification of intraspinal inclusion cysts (OR 5.6, p = 0.023) were associated with an infective presentation. There was no significant association between the presence of an intradural tract discovered at surgery and an infective presentation. CONCLUSIONS Surgery for the treatment of spinal dermal tract carries a low morbidity. While it seems intuitive that tracts without intradural extension carry a low risk of spinal cord tethering, it is not possible to reliably detect these cases using MRI. Similarly, intraspinal dermoid cannot be reliably excluded using MRI and carries an increased risk of infection. These points justify excision together with intradural exploration of all spinal dermal sinus tracts.

Unusual presentation of congenital dermal sinus: tethered spinal cord with intradural epidermoid and dual paramedian cutaneous ostia

The authors present the first report of spinal congenital dermal sinus with paramedian dual ostia leading to 2 intradural epidermoid cysts. This 7-year-old girl had a history of recurrent left paramedian lumbosacral subcutaneous abscesses, with no chemical or pyogenic meningitis. Admission MRI studies demonstrated bilateral lumbar dermal sinus tracts and a tethered spinal cord. At surgery to release the tethered spinal cord the authors encountered paramedian dermal sinus tracts with dual ostia, as well as 2 intradural epidermoid cysts that were not readily apparent on MRI studies. Congenital dermal sinus should be considered in the differential diagnosis of lumbar subcutaneous abscesses, even if the neurocutaneous signatures are located off the midline.

Spinal congenital dermal sinuses: a 30-year experience

OBJECTIVE

Dermal sinus tracts are an uncommon form of spinal dysraphism often presenting in childhood with skin findings, neurologic deficit, or infection. We reviewed our surgical experience, examining presenting symptomatology, operative findings, and patient outcomes.

METHODS

A retrospective analysis of operated dermal sinus tract cases by the senior author (A.H.M.) from 1970 to present was made.

RESULTS

Twenty-eight patients were identified; 17 female and 11 male. Five cervical, 4 thoracic, 9 lumbar, and 9 lumbosacral tracts were explored. Sixteen patients presented at <1 year of age, and 12 were >1 year. Reasons for referral included cutaneous findings (15), neurologic deficit (8), foot abnormalities (4), infection (3), pain (2), and scoliosis (1). Our initial examination revealed cutaneous findings (eg, sinus ostea, pigmentation changes, erythema, skin tags, subcutaneous masses) in 27 patients and neurologic deficit in 19. Age-related differences were apparent. Patients >1 year were more likely to have neurologic deficit (92%) as compared with those <1 year (50%). Bifid spinous processes were noted at dural tract entry in 17 patients. Twenty-two tethered cords, 14 inclusion tumors, and 6 patients with evidence of arachnoiditis were found intraoperatively. Mean follow-up was 33 months. Eleven (39%) remained neurologically intact, 12 (43%) improved, 2 (7%) were unchanged, and 3 (11%) were worse with 2 having decreased perianal sensation and 1 slightly worsened motor function postoperatively.

CONCLUSIONS

Although most patients were referred for cutaneous stigmata evaluation, >50% had neurologic deficit, intradural tumors, or tethered cords. Skin findings identification should initiate prompt radiologic evaluation and neurosurgical intervention with intradural exploration. Timely intervention may preserve or improve neurologic function in these patients.

Anomalous ependyma inducing split cord and meningomyelocele?

The case is that of a female fetus of 17 to 18 weeks' gestation with major defects of the central nervous system: (1) The thoracic vertebrae demonstrated rachischisis, with segmental diplomyelia; the duplicated cords were dissimilar in size and lay side by side within a single meningeal sheath lacking a dividing septum or spur. Cranially to the divided cord lay an unsplit segment of "open cord" lacking the posterior elements and exposing the centrally placed ependyma of the central canal flanked by glial and epidermal lining, respectively; it could be regarded as an example of a meningomyelocele. (2) Heterotopic massed ependymal cells, some of which were actively proliferating, were associated with the choroid plexus in the brain. Minor anomalies included cerebellar heterotopia and the malpositioning of dorsal root ganglia outside the meningeal sheath. Because the ependyma is such a powerful inducer of the development of neighboring tissue, the findings could be united by a common pathogenic theme, viz problematic ependymal development and migration within both the brain and spinal cord. The causative agent responsible for these abnormalities remains unidentified, but the balance of evidence suggests that its effect was felt during the second week of postconceptual age.

"Acquired" Chiari I malformation. Case report

Tonsillar descent of the cerebellum in Chiari I malformations is often considered a congenital defect. A patient is presented in whom magnetic resonance (MR) imaging revealed normally positioned cerebellar tonsils; however, 1 year later MR imaging was repeated for evaluation of gait abnormalities and showed descent of the cerebellar tonsils. This case illustrates worsening symptoms with progressive descent of the cerebellar tonsils and suggests that Chiari I malformations can evolve postnatally.