Dorsal spurs in Type I split cord malformations (SCM-I) are infrequent findings. The pathogenesis of the same is debatable. The objective of this study is to analyze our experience with SCM-I patients having dorsal bony spurs.
Retrospective analysis of SCM patients operated from 2010 to 2017 was performed. Their demographic profile, clinic-radiological features, operative findings, and outcome following surgery were recorded.
Twenty-four cases of Type I SCM harboring dorsal bony spurs were identified with mean age of 4.96 years. The commonest split site was lumbar, documented in 62.5%. Scoliosis was observed in 58.3%. Pre-operative neurological deficits were seen in 66.6% cases with asymmetric weakness of limbs seen in 16.6%. There was no new neurological deficit observed post-operatively.
This is the largest series of dorsal spurs occurring in SCM, reported in literature so far. Meticulous pre-operative evaluation and imaging are important to identify dorsal spurs for appropriate management and good clinical outcome. Differentiating dorsal spur from ventral spur is important as it has a bearing on surgical approach.

Spine duplication is considered rare, a more serious form of split cord malformation. Ultrasonographic evaluation of the spine in the second trimester is central to the antenatal diagnosis of spinal malformations. Here, we report a case of thoraco-lumbar spine duplication associated with lipomyelomeningocele diagnosed by ultrasonography at 19 weeks of gestation. To the best of our knowledge, this is the first case report of spine duplication diagnosed by antenatal ultrasonography.

BACKGROUND: Tethered cord syndrome (TCS) secondary to split cord malformation (SCM) is rare in adulthood. There is as yet no consensus about the optimal treatment method for adult patients with SCMs and degenerative spine diseases such as lumbar stenosis, spondylolisthesis and ossification of the ligamentum flavum (OLF). The tethered cord poses a great challenge to the decompression and fusion procedures for the intraoperative stretching of the spinal cord, which might lead to deteriorated neural deficits. Here, we report on a case to add our treatment experience to the medical literature.
METHODS: We treated a 67-year-old female patient with type II SCM suffering from lumbar disc herniation, degenerative lumbar spondylolisthesis and thoracic OLF. The patient underwent thoracolumbar spinal fusion and decompression surgery for severe lower back pain, extensive left lower limb muscle weakness and intermittent claudication. After the thoracolumbar surgery, without stretching the tethered cord, the patient achieved complete relief of pain and lower extremity weakness at final follow-up.
CONCLUSIONS: For adult patients with underlying TCS secondary to SCM coupled with thoracic OLF and lumbar spondylolisthesis, a thoracolumbar fusion surgery could be safe and effective with the tethered cord untreated. It is critical to design individualized surgical protocols to reduce the stretch of the low-lying spinal cord.

We report a case of a spinal intradural arachnoid cyst in a thirty year old female with a previously undiagnosed and untreated diastematomyelia. The cyst was located exactly between the two hemi-cords of the split cord malformation. The patient was treated successfully by laminoplasty and total removal of the cyst. Additionally, sectioning of the filium terminale was done in the same sitting by a separate incision. This case posed a diagnostic dilemma. Though the clinical findings favoured an extramedullary lesion, the possibility of cystic degeneration in the spinal cord due to the tethered cord syndrome could not be completely negated. Spinal intradural arachnoid cysts have been reported in association with various neural tube defects, mainly in the paediatric age group. However, such a lesion associated with diastematomyelia in an adult, to the best of our knowledge, has not been reported previously.

Intraoperative neurophysiological monitoring (IONM) consists of a group of neurodiagnostic techniques that assess the nervous system\'s functional integrity during surgical operations. A retrospective analysis of a pediatric female patient was conducted who underwent 12 operations for the correction of scoliosis, tethered cord, and split spinal cord wherein IONM played an important role. From age 3 to 6, she underwent six procedures including a release of the tethered cord, resection of the filum terminale, removal of a T11-T12 bony spur, release of L3 adhesions, repair of subcutaneous meningocele, and correction of scoliosis with a vertical expandable prosthetic titanium rod (VEPTR) technique without the use of IONM. However, a multimodality IONM protocol with somatosensory evoked potentials, transcranial electrical motor evoked potentials (TCeMEP), and an electromyogram was utilized during the later procedures. At age 6 (the seventh procedure), a VEPTR expansion was performed, with loss and recovery of the lower extremity motor evoked potentials. The postoperative magnetic resonance imaging (MRI) showed a partial split cord malformation with retethering of the spinal cord. We repaired her split cord malformation and tethered cord while employing IONM. Using IONM for her operation was crucial because a sudden significant loss of TCeMEP resulted in a cancellation of the procedure; the MRI showed a thick remnant attached to the spinal cord. If the procedure was performed without IONM, we could have missed the underlying pathology, an error that may have resulted in paraplegia. We strongly recommend using IONM during high-risk surgical procedures to help significantly reduce the risk of permanent postoperative complications.

Split cord malformations (SCM) are a common pediatric abnormality where children present with features of tethering and backache along with varying neurological deficits. Multiple neural tube defects may co-exist in children having defects of primary and/or secondary neurulation. Co-existent neurenteric cysts along with type 1 SCM have been described very rarely in the literature. We report a case of silent neurenteric cyst at conus medullaris with SCM type 1 where the cyst was missed in the preoperative imaging. Until date, only 8 such cases of neurenteric cysts with SCM at lumbar region have been reported. We review the literature regarding co-existing dual pathologies of neurenteric cysts and type 1 SCMs in light of limited capacity of imaging modalities to detect small neurenteric cysts in presence of co-existent neural tube defects. Multiple spinal neural tube defects in children need more attention and precise microneurosurgical skills as management differs in each of them. Co-existence of such pathologies detected intra-operatively may need modifications in preoperative planning to achieve the best possible outcomes.