Risk of occult spinal dysraphism based on lumbosacral cutaneous manifestations

Atavistic and vestigial anatomical structures in the head, neck, and spine: an overview

Organisms may retain nonfunctional anatomical features as a consequence of evolutionary natural selection. Resultant atavistic and vestigial anatomical structures have long been a source of perplexity. Atavism is when an ancestral trait reappears after loss through an evolutionary change in previous generations, whereas vestigial structures are remnants that are largely or entirely functionless relative to their original roles. While physicians are cognizant of their existence, atavistic and vestigial structures are rarely emphasized in anatomical curricula and can, therefore, be puzzling when discovered incidentally. In addition, the literature is replete with examples of the terms atavistic and vestigial being used interchangeably without careful distinction between them. We provide an overview of important atavistic and vestigial structures in the head, neck, and spine that can serve as a reference for anatomists and clinical neuroscientists. We review the literature on atavistic and vestigial anatomical structures of the head, neck, and spine that may be encountered in clinical practice. We define atavistic and vestigial structures and employ these definitions consistently when classifying anatomical structures. Pertinent anatomical structures are numerous and include human tails, plica semilunaris, the vomeronasal organ, levator claviculae, and external ear muscles, to name a few. Atavistic and vestigial structures are found throughout the head, neck, and spine. Some, such as human tails and branchial cysts may be clinically symptomatic. Literature reports indicate that their prevalence varies across populations. Knowledge of atavistic and vestigial anatomical structures can inform diagnoses, prevent misrecognition of variation for pathology, and guide clinical interventions.

Late diagnosis of dorsolumbar lipomyelomeningocele with tethered cord in a middle aged adult: A case report from Nepal

Closed spinal dysraphism can present with diagnostic issues in settings with limited resources, when knowledge of the disorder and specialized radiological studies, such as magnetic resonance imaging (MRI), may not be readily available. Undiagnosed cases can develop serious neurological deficits. Here, we describe a case of dorsolumbar lipomyelomeningocele, a type of closed spinal dysraphism, presenting in a middle aged with paraplegia complicated by bed sores. A 38-year-old female with no significant past medical history experienced gradually progressive weakness of bilateral lower limbs over 9 years. On physical examination, patient had a soft swelling with hairy tuft over the lumbar spine, paraplegia, grade III bed sore over the gluteal region, and sensory loss below L1 sensory level. Her bowel and bladder sensation were decreased. The soft tissue swelling over her back was not evaluated appropriately before this presentation. MRI of the spine revealed dorsolumbar lipomyelomeningocele with tethered spinal cord.

Role of ultrasonography in screening of spinal dysraphism in infants at risk

Background

Spinal dysraphism (SD) encompasses congenital spinal defects that result from inappropriate fusion of the different midline osseous, mesenchymal, and neural elements. The primary tools for diagnosis of SD are both spinal ultrasonography (USG) and magnetic resonance imaging (MRI). Spinal USG is growingly being used as an initial screening modality with sensitivities and accuracies equivalent to those of MRI. Anorectal malformations (ARM) have ultimate association with many other congenital abnormalities, of which spinal dysraphism is one of the most common. The main aim of study was to assess the diagnostic accuracy of spinal USG as a screening modality in comparison with MRI in infants with closed spinal dysraphism. We also endeavored to highlight the associated spinal dysraphism radiological findings in patients with either ARM or back cutaneous stigmata.

Results

Our prospective diagnostic comparative study included 33 patients, all of whom underwent both MRI and USG. Both MRI and USG showed appreciable agreement in the assessment of spinal dysraphism. In comparison with the gold standard MRI, spinal USG revealed comparable diagnostic metrics: specificity (98.6–100%), sensitivity (66.6–91.6%), PPV (90–100%) and NPV (94.1–98.7%) in diagnosis of different types of spinal dysraphism. The main clinical presentation of nineteen patients was anorectal malformation (ARM), 11 of whom (57.9%) had evidence of associated spinal dysraphism. The most common types of ARM were cloacal malformation, recto-urethral fistula, and rectal atresia with no fistula. On the other hand, sixteen patients were mainly presented with back cutaneous stigmata, 11 of whom (68.8%) had associated spinal dysraphism. The most common presenting cutaneous stigmata were low back swelling and atypical dimples.

Conclusion

The front-line screening modality for infants with closed SD should be spinal USG, however, its main limitation is the restrained time window in the first 6 months of life. Infants with ARM should be screened for spinal anomalies, especially those with high and complex types. Infants with high-risk back cutaneous stigmata should be similarly screened, as well.