Split cord malformation with dorsally located bony spur: Report of four cases and review of literature

Abstract

Split cord malformations (SCM) with a dorsally located bony spur are a very rare entity. The authors report a series of four such cases. The literature is reviewed regarding the pathogenesis and management of this uncommon variant of SCM. The presenting features include – scoliosis with motor and autonomic dysfunction (n = 1), scoliosis with cutaneous patch (n = 1), hypertrichotic area (n = 1), and motor deficits alone (n = 1). The location of spur was thoracic and lumbar in two patients (50%) each. Low-lying conus was present in three patients. Long segment syrinx was present in one patient. With respect to the bony anomalies, two patients had a hypertrophied posterior arch (HPA) and one patient had a dysraphic spine. All patients underwent surgical excision of the spur with detethering, if a low-lying conus was present. Two patients developed transient worsening of the neurological status after surgery which recovered at the time of the last follow-up; in both these patients, there was a HPA and a low-lying conus. Surgical excision of the spur with detethering of filum, in cases of low-lying conus, is the treatment of choice. Risk of post-operative worsening of the neurological status is increased in cases in which there is concomitant presence of HPA.

An unusual case of split cord malformation with simultaneous ventral and dorsal bony spur at a single site: A Technical Challenge

“…[ 1 ] Generally, in cases of bony septum, a single bony spur usually arises from the posterior surface of the vertebral body, but there have been a few case reports of spurs arising from the posterior arch. [ 7 8 9 ] Chandra et al . [ 7 ] discussed two hypotheses for posterior origin of bony spur, including (1) disconnection of ventral cell mass after dorsal migration of meninx primitiva cells and (2) initial migration of meninx primitiva cells around the hemicords instead of between them to accumulate along the dorsal arch.…”

Type 1 split cord malformation: The significance of the 3D orientation of the bony spur, its clinical relevance, and surgical nuances

“…So it may be possible that during their genesis, the posterior bony elements gave rise to the abnormal bony proliferation. [ 5 7 8 ]…”

“…Two patients showed mild paraparesis in the previous series of four patients. [ 8 ] Patients with dorsal bony spurs show better clinical outcome (85.7%) when compared to their ventral counterparts. The dorsal spurs have higher incidence of scoliosis deformity (28.6%).…”