Butterfly Vertebrae: A Systematic Review of the Literature and Analysis

Butterfly Vertebra: A Retrospective Study of 30 Patients

BACKGROUND

Butterfly vertebra (BV) is a rare congenital spinal anomaly for which there is a paucity of large-scale retrospective studies and established guidelines for treatment. The objective of this study was to elucidate the clinical characteristics, imaging findings, and therapeutic approaches for BV.

METHODS

We conducted a retrospective analysis of 30 patients diagnosed with BV at our hospital from 2009 to 2023, examining clinical data, imaging findings, and clinical interventions.

RESULTS

The analysis comprised a cohort of 30 patients, consisting of 15 males and 15 females, with a mean age of 27.63 ± 19.84 years. Imaging studies indicated that the majority of vertebral bodies affected by BV were single-segmented (63.3%, 19/30) and less commonly multi-segmented (36.7%, 11/30). These findings frequently coexisted with other medical conditions, most notably spinal scoliosis (76.7%, 23/30). Furthermore, the study identified a range of spinal abnormalities among patients, including hemivertebral deformity (30.0%, 9/30), spinal cleft (10.0%, 3/30), lumbar disc protrusion or herniation (10.0%, 3/30), vertebral slippage (10.0%, 3/30), thoracic kyphosis deformity (6.67%, 2/30), vertebral fusion deformity (6.67%, 2/30), compressive fractures (3.3%, 1/30), and vertebral developmental anomalies (3.3%, 1/30). Clinical intervention resulted in symptom relief for 23 nonsurgical patients through lifestyle modifications, analgesic use, and physical therapy. Seven surgical patients underwent appropriate surgical procedures, leading to satisfaction and adherence to regular postoperative follow-up appointments.

CONCLUSIONS

BV is a rare vertebral anomaly that can be easily misdiagnosed due to its similarity to other diseases. Consequently, it is imperative to enhance vigilance in the differential diagnosis process in order to promptly recognize BV. Furthermore, in cases where patients present with additional associated radiographic findings, a thorough evaluation is typically warranted and timely measures should be taken for treatment.

Association of spinal cord abnormalities with vertebral anomalies: an embryological perspective

PURPOSE

To analyze the relationship between spinal cord and vertebral abnormalities from the point of view of embryology.

METHODS

We analyzed the clinical and radiological data of 260 children with different types of spinal cord malformations in combination with vertebral abnormalities.

RESULTS

Among 260 individuals, approximately 109 presented with open neural tube defects (ONTDs), 83 with split cord malformations (SCMs), and 83 with different types of spinal lipomas. Pathological spina bifida emerged as the most frequent vertebral anomaly, affecting 232 patients, with a higher prevalence in ONTD. Vertebral segmentation disorders, including unsegmented bars, butterfly vertebrae, and hemivertebrae, were present in 124 cases, with a higher prevalence in SCM. The third most common spinal anomaly group consisted of various forms of sacral agenesis (58 cases), notably associated with blunt conus medullaris, spinal lipomas, and sacral myelomeningocele. Segmental aplasia of the spinal cord had a typical association with segmental spinal absence (N = 17).

CONCLUSION

The association between SCM and neuroenteric cyst/canal and vertebral segmentation disorders is strong. High ONTDs often coincide with pathological spina bifida posterior. Type 1 spinal lipomas and focal spinal nondisjunction also correlate with pathologic spina bifida. Segmental spinal absence or dysgenesis involves localized spinal and spinal cord aplasia, sometimes with secondary filar lipoma.

Vertebral anomalies and VACTERL association in pontine tegmental cap dysplasia: a paediatric case report

This case report highlights vertebral segmental anomalies and the fact that the child presented has a rare neurologic condition called pontine tegmental cap dysplasia. Additionally, this case aims to educate learners in developing a differential diagnosis for vertebral and cardiac anomalies such as VACTERL syndromes and common syndromes associated with butterfly vertebrae in children and adolescents.

A case study on the pitfalls in prenatal ultrasonic detection of butterfly vertebra

Introduction

Butterfly vertebra is a rare congenital anomaly that is observed both in isolation and also as part of syndromic diseases. In prenatal ultrasonic scans the typical shapes of the two halves for butterfly vertebra are wedge-shaped or triangular. In the case we presented, the 3 dimensional computed tomography (3D CT) showed that the shape was unusual and rare. To improve the prenatal ultrasonic discriminability of this rare form of butterfly vertebra we used multi-directional ultrasonic images, corresponding to postpartum 3D CT images.

Case report

A 25-year-old woman was referred to our department for ultrasound screening. The routine fetal back spinal scan yielded findings indicative of an anomaly within the ninth thoracic vertebral body. The affected vertebra was examined by two-dimensional (2D) and three-dimensional (3D) ultrasound while the fetus was prone and supine. The focussed scanning of the fetal spine from the back, anterior and lateral approaches aided us to reach the final prenatal diagnosis of butterfly vertebra with asymmetric halves.The diagnosis of butterfly vertebra was confirmed by the radiologist with 3D CT after the woman chose to terminate the pregnancy due to multiple malformations. In 3D CT, the body of the ninth thoracic vertebra appeared to be two lateral halves of different sizes, and the bigger half was C-shaped. When prenatal ultrasonic images and postnatal CT images were compared, the echoic shape of the affected vertebra scanned from the front right side was very similar to the CT.

Conclusion

Due to the variable sizes and shapes of vertebrae affected in butterfly vertebra, prenatal diagnosis can be difficult using ultrasound. When the presence of fetal vertebral abnormalities is suspected, it is imperative for sonographers to adopt a comprehensive approach that extends beyond the conventional spinal examination performed solely from the dorsal aspect of the fetus. Instead, a thorough assessment should involve scanning the fetus from various angles, including anterior and lateral perspectives, in order to obtain a comprehensive and detailed evaluation of the identified vertebra.

Extraprostatic incidental findings on prostate mpMRI: A pictorial review from the ESUR junior network

The role of multiparametric MRI (mpMRI) in prostate cancer setting is increasingly consolidated and, as a result, its usage in clinical practice is in exponential growth. However, beyond the prostate gland, several key structures are included in the field of view of mpMRI scans. Consequently, various extra-prostatic incidental findings (IFs) belonging to different anatomical systems can be accidentally recognized. Therefore, it is mandatory for a radiologist to be familiar with the wide range of pathologies potentially encountered, to guide management and avoid patient anxiety and costs due to additional work-up prompted by clinically insignificant extra-prostatic findings. With this pictorial review, we aim to illustrate a wide range of IFs that can be detected when performing mpMRI of the prostate, focusing on their imaging characteristics, differential diagnosis, and clinical relevance. Additionally, we propose the CheckDEEP, the Checklist for DEtection of ExtraProstatic findings, to be used for a thorough evaluation of target areas within each anatomical system.

A rare incidental finding of an isolated S1 butterfly vertebra: A case report

Butterfly vertebra is an uncommon type of vertebral anomaly (sometimes referred to as a sagittal cleft vertebra or an anterior rachischisis) caused by persistent notochordal tissue. Butterfly vertebrae of S1, which is rarer anomaly compared to thoraco-lumbar region, may be associated with syndromic causes and usually asymptomatic with a funnel shaped defect seen in imaging which can later give rise to disk problems, facet joint degeneration and chronic low back pain. We here share a case of 35-year female presented with intermittent low back pain diagnosed with S1 butterfly vertebrae as an incidental finding in radiograph and magnetic resonance imaging. Radiologist and orthopedicians should be vigilant about this rare entity as a differential of low back pain and its association with other syndromes.

Vertebral anomalies in a natural population of Taricha granulosa (Caudata: Salamandridae)

Developmental plasticity, a common pattern in lissamphibian evolution, results in numerous alternative morphologies among species and also within populations. In the present study, a natural population of the salamander Taricha granulosa (Salamandridae) was examined to detect variation in the vertebral count and to identify potential deformities of their vertebral column. The number of trunk vertebrae varied between 11 and 13 and we recorded 58 individuals with 69 anomalous vertebral elements. These anomalies range from congenital malformations (block vertebrae, unilateral bars, hemivertebrae), extra ossifications in the haemal region, to posttraumatic pathologies. Most osseous pathologies were encountered in the caudal region of the axial skeleton. Our data suggest a high frequency of vertebral malformations in salamanders; however, the identification of the exact causes remains challenging.

A Concomitant Occurrence of the Atlantoaxial Subluxation with Rare Vertebral Formation and Segmentation Defects

An atlantoaxial subluxation from the unstable Os odontoideum by the failure of proper integrations between the embryological somites might be a commonly reported pathology. However, its suspicious origin or paralleled occurrence with other congenital anomalies of vertebral body might be a relatively rare phenomenon. The authors present two cases, who simply presented with clinical signs of prolonged, intractable cervicalgia without any neurological deficits, revealed this rare feature of C1–2 subluxation from the unstable, orthotropic type of Os odontoideum that coincide with congenitally fused cervical vertebral bodies between C2–3. Surprisingly, in one case, when traced from the lower cervical down to the thoracic-lumbar levels during the preoperative work-up process, was also compromised with multi-level butterfly vertebrae formations. Presented cases highlight the association of various congenital vertebrae anomalies and the rationale to fuse only affected joints.

Transformed notochordal cells trigger chronic wounds destabilizing the vertebral column and bone homeostasis

Notochordal cells play a pivotal role in vertebral column patterning, contributing to the formation of the inner architecture of intervertebral discs (IVDs). Their disappearance during development has been associated with reduced repair capacity and IVD degeneration. Notochord cells can give rise to chordomas, a highly invasive bone cancer associated with late diagnosis. Understanding the impact of neoplastic cells during development and on the surrounding vertebral column could open avenues for earlier intervention and therapeutics. We investigated the impact of transformed notochord cells in the zebrafish skeleton using a line expressing RAS in the notochord under the control of the kita promoter, with the advantage of adulthood endurance. Transformed cells caused damage in the notochord and destabilised the sheath layer, triggering a wound repair mechanism, with enrolment of sheath cells (col9a2⁺) and expression of wt1b, similar to induced notochord wounds. Moreover, increased recruitment of neutrophils and macrophages, displaying abnormal behaviour in proximity to the notochord sheath and transformed cells, supported parallels between chordomas, wound and inflammation. Cancerous notochordal cells interfere with differentiation of sheath cells to form chordacentra domains, leading to fusions and vertebral clefts during development. Adults displayed IVD irregularities reminiscent of degeneration, including reduced bone mineral density and increased osteoclast activity, along with disorganised osteoblasts and collagen, indicating impaired bone homeostasis. By depleting inflammatory cells, we abrogated chordoma development and rescued the skeletal features of the vertebral column. Therefore, we showed that transformed notochord cells alter the skeleton during life, causing a wound-like phenotype and activating chronic wound response, suggesting parallels between chordoma, wound, IVD degeneration and inflammation, highlighting inflammation as a promising target for future therapeutics.

This article has an associated First Person interview with the first author of the paper.

Summary: Analyses using a zebrafish line expressing RAS in the notochord, under the control of the kita promoter, revealed that transformed notochord cells alter the skeleton during life, causing a wound-like phenotype and activating chronic wound response.

Butterfly vertebra and block vertebra cause overdiagnosis in trauma patients

Butterfly vertebra and block vertebra are usually reported incidental radiological view, which is a rare congenital defect of spine. Butterfly vertebra is a body formation characterized by anterior and median aplasia. The block vertebra is the result of an embryonically incomplete separation of vertebral bodies or arches or both. This rare congenital anomalies butterfly and block vertebra are usually stable and do not cause clinical symptoms.

Thoracolumbar kyphoscoliotic deformity with neurological impairment secondary to a butterfly vertebra in an adult

STUDY DESIGN

Case report.

OBJECTIVE

To describe a rare case of thoracolumbar kyphoscoliosis secondary to a butterfly vertebra in an adult, and its surgical correction technique.

BACKGROUND

Kyphoscoliosis secondary to an isolated butterfly vertebra is rare and its management can be very challenging.

METHODS

We report the case of a 39-year-old male, complaining of chronic middle and low back pain with unsteady gait and altered sensation of lower extremities. Full spine anteroposterior and lateral X-rays revealed a thoracolumbar kyphosis with an angulation of 60° between T10 and T12, with a short thoracolumbar scoliosis of 32 degrees. CT scan confirmed the presence of a butterfly vertebra at the level of T11 with posterior arch fusion between T10 and T12. MRI showed cord compression at the apex of the kyphosis associated to syringomyelia.

RESULTS

The patient underwent a posterior resection of the T11 butterfly vertebra with instrumentation from T8 to L2, and use of a one-sided domino on the convex side and a mesh cage on the concave side for asymmetrical correction and vertebral height preservation. Thoracolumbar kyphosis was corrected to 10°. Scoliosis was corrected to 6°. He could walk on day 2 with a satisfactory clinical and radiological result at 2 years.

CONCLUSION

Literature is sparse on the management of thoracolumbar kyphoscoliosis secondary to butterfly vertebra in the context of neurological impairment. The current case described a surgical treatment strategy to correct both deformity planes simultaneously by a vertebral resection performed through a posterior only approach.

Spinal cord injury in an adult patient with thoracic butterfly vertebra: a case report and review of the literature

Background

Butterfly vertebrae are a rare congenital vertebral anomaly. An overlap of this spinal anomaly with other diseases has been reported. However, to the authors’ knowledge, the coexistence of butterfly vertebrae and spinal cord injury has not been reported in the literature.

Case presentation

A 42-year-old male was admitted to our emergency department after a motor vehicle accident. His complaint was back pain, and he was unable to move both lower limbs. Upon physical examination, the patient was not ambulatory. Sensory examination revealed the absence of sensation below the T12 level. The strength of the bilateral lower limbs was grade 0. The patient received a radiographic evaluation. The initial diagnosis was T11 fracture with complete paraplegia of the lower limbs. Magnetic resonance imaging (MRI) was then performed. Sagittal MRI demonstrated an isointense lesion on T1-weighted imaging and a high-signal spindle-like lesion on T2-weighted imaging of the spinal cord adjacent to the T11 vertebra. The fat-suppressed sequence also revealed hyperintensities of the cord. There was no evidence of acute injury of the T11 vertebral body except for cuneiform anterior wedging. The patient was ultimately diagnosed with complete paraplegia with a T11 butterfly vertebra. He underwent urgent posterior decompressive and fixation surgery from T10 to T12. His postoperative recovery was uneventful.

Conclusions

The coexistence of a butterfly vertebra with spinal cord injury was reported for the first time. Although butterfly vertebrae may be incidentally detected, it is important to be familiar with their radiographic features to distinguish them from fractures.

Multi-level sagittally cleft vertebrae: a case report and review of the literature

The term "sagittal cleft vertebra" (SCV) denotes a rare embryologically derived longitudinal defect within the vertebral body, which is clinically and radiologically challenging to diagnose in isolation. This defect results in two hemivertebrae, which ossify discordantly, ultimately leading to a sagittal cleft through the vertebral body. Often presenting with low back pain or concomitant with an associated syndromic illness, SCV is often found incidentally and can mimic vertebral compression fractures radiographically. Treatment of SCV has largely been conservative and symptomatic. With only 109 reported cases in the current literature, we present a unique case of multiple SCV throughout the thoracolumbar region in an adolescent patient. We performed a review of the literature to identify published cases of SCV to date. We searched PUBMED using the terms "sagittal cleft vertebrae", "butterfly vertebrae", and "anterior rachischisis". Abstracts were screened for reports specifically involving original cases of SCV. Given the well-established association with syndromic illnesses, finding an SCV warrants further investigation for other abnormalities of the musculoskeletal, cardiac, and genitourinary systems. Complex management strategies are rare unless the SCV is associated with an aberrant syndrome, disc herniation or severe musculoskeletal abnormality, or symptomatic disc herniation requiring surgical management. Further studies should focus on uncovering the genetic markers leading to the cleft vertebral bodies, with a focus on early screening and monitoring of patients who could be predisposed to the condition.