Chiari type III malformation associated with Klippel-Feil syndrome, a case report with a narrative review of the literature.

BACKGROUND: Chiari malformation type III (CM III), a rare hindbrain anomaly, often presents with various concurrent anomalies. This paper reports a unique case of CM III associated with Klippel-Feil syndrome (KFS), a condition previously unreported in Saudi Arabia and documented in only one other case globally in Turkey. This study aims to share insights into the unusual association between CM III and KFS, considering their close embryological development and involvement in the craniocervical junction. METHODOLOGY: The study presents a case of a 2.5-year-old female diagnosed with CM III and KFS. Diagnostic tools such as ultrasound, CT scans, MRI, and physical examinations were used to confirm the patient's condition. Surgical interventions, including decompression and encephalocele repair, were performed. RESULTS: Successful surgical interventions, including encephalocele repair and duraplasty, were carried out. Follow-up visits indicated a stable condition, marked improvement in lower limb strength, and the patient's ability to walk with assistance. CT follow-up affirmed a satisfactory surgical outcome. CONCLUSION: This case study illustrates the potential for an optimistic prognosis in CM III, even when accompanied by complex conditions such as KFS, through early diagnosis and intervention. It underscores the significance of antenatal screening for effective care planning and calls for further research and publications due to the rarity of this association. These findings contribute to our understanding of CM III and its related conditions, emphasizing the need for open-minded consideration of potential embryological associations.

Congenital Cervical Spinal Deformities.

Malformations of the cervical spine are a challenge in pediatric orthopedic surgery since the treatment options are limited. These congenital anomalies are often syndrome-related and have multiple repercussions on the function and statics of the cervical spine in all three planes. They are related to developmental abnormalities during the somite segmentation that occurs during the third week of embryonic development. Successful somitogenesis requires proper functioning of a clock regulated by complex signaling pathways that guide the steps needed to form the future spine. There is no specific classification for vertebral malformations at the cervical level. To characterize the progressive nature of a malformation, one must use general classifications. In the specific case of Klippel-Feil syndrome, these malformations can affect several vertebral levels in a continuous or discontinuous manner, but also the vertebral body and vertebral arch in a variable way. Thus, establishing a reliable prognosis in the coronal and sagittal planes is a complex undertaking. While technical mastery of certain osteotomy procedures has led to advances in the surgical treatment of rigid deformities of the cervical spine, the indications are still very rare. Nevertheless, the procedure has become safer and more accurate because of technical aids such as surgical navigation, robotics and 3D printed models or patient-specific guides. Occipitocervical transitional anomalies have embryological specificities that can explain the bony malformations seen at this level. However, most are rare, and the main concern is identifying any instability that justifies surgical stabilization. The presence of a cervical spine anomaly should trigger the search for occipitocervical instability and vice-versa.

Application of C2 subfacetal screws for the management of atlantoaxial dislocation in patients with Klippel-Feil syndrome characterized by a narrow C2 pedicle and high-riding vertebral artery.

OBJECTIVE: This study aims to investigate the clinical application and feasibility of C2 subfacetal screws in patients with Klippel-Feil syndrome (KFS), narrow C2 pedicles, and high-riding vertebral arteries (HRVAs). METHODS: The clinical data of seven patients with KFS, atlantoaxial dislocation, narrow C2 pedicles, and HRVAs treated with C2 subfacetal screws were analyzed in this retrospective study. The internal height, isthmus height, and pedicle width of C2 vertebra were measured using preoperative computed tomography (CT). Subfacetal screws were inserted for 7 patients (12 sides). The position and length of the screws were observed using postoperative CT. Intraoperative dura mater and vertebral artery (VA) injuries were recorded. Bone fusion was observed using follow-up CT. RESULTS: The internal height was 10.5 ± 3.2 mm, the isthmus height was 3.7 ± 1.8 mm, the pedicle width was 3.0 ± 1.4 mm, and the screw length was 19.7 ± 1.5 mm. All patients had HRVAs and narrow pedicles. No injury to the dura mater and vertebral artery (VA) occurred in this group of patients. Bone fusion was achieved in all patients during follow-up. CONCLUSIONS: In patients with KFS, HRVA, and a narrow C2 pedicle, there is sufficient space below the C2 articular surface for screw insertion. When the pedicle is narrow and the C2 pedicle screw is not suitable for placement due to possible injury to the VA, subfacetal screws are a feasible alternative.

The predictive ability of occipital to C3 angle for dysphagia after occipitocervical fusion in patients with combined C2-3 Klippel-Feil syndrome.

BACKGROUND: Improper occipitocervical alignment after occipitocervical fusion (OCF) may lead to devastating complications, such as dysphagia and/or dyspnea. The occipital to C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa) have been used to evaluate occipitospinal alignment. However, it may be difficult to identify the inferior endplate of the C2 vertebra in patients with C2-3 Klippel-Feil syndrome (KFS). The purpose of this study aimed to compare four different parameters for predicting dysphagia after OCF in patients with C2-3 KFS. METHODS: There were 40 patients with C2-3 KFS undergoing OCF between 2010 and 2019. Radiographs of these patients were collected to measure the occipital to C3 angle (O-C3a), O-C2a, occipito-odontoid angle (O-Da), occipital to axial angle (Oc-Axa), and narrowest oropharyngeal airway space (nPAS). The presence of dysphagia was defined as the patient complaining of difficulty or excess endeavor to swallow. Patients were divided into two groups according to whether they had postoperative dysphagia. We evaluated the relationship between each of the angle parameters and nPAS and analyzed their influence to the postoperative dysphagia. RESULTS: The incidence of dysphagia after OCF was 25% in patients with C2-3 KFS. The Oc-Axa, and nPAS were smaller in the dysphagia group compared to non-dysphagia group at the final follow-up (p < 0.05). Receiver-operating characteristic (ROC) curves showed that dO-C3a had the highest accuracy as a predictor of the dysphagia with an area under the curve (AUC) of 0.868. The differences in O-C3a, O-C2a, O-Da, and Oc-Axa were all linearly correlated with nPAS scores preoperatively and at the final follow-up within C2-3 KFS patients, while there was a higher R2 value between the dO-C3a and dnPAS. Multiple linear regression analysis showed that the difference of O-C3a was the only significant predictor for dnPAS (ß = 0.670, p < 0.001). CONCLUSIONS: The change of O-C3a (dO-C3a) is the most reliable indicator for evaluating occipitocervical alignment and predicting postoperative dysphagia in C2-3 KFS patients. Moreover, dO-C3a should be more than - 2° during OCF to reduce the occurrence of postoperative dysphagia.

Rare association of Klippel-Feil syndrome with situs inversus totalis and review of the genetic background.

Klippel-Feil syndrome (KFS) is a rare congenital anomaly in forming the cervical vertebrae resulting in the fusion of two or more of the vertebrae. KFS is associated with many congenital anomalies, some of which are common and well known. Here, we report a child with an extremely rare association of KFS with situs inversus totalis (SIT). Both KFS and SIT are genetically heterogeneous and their co-occurrence suggests a high possibility of sharing the same underlying causative agent. Here, we review the genetic background that is known for these two conditions in the literature.

The VANGL1 P384R variant cause both neural tube defect and Klippel-Feil syndrome.

BACKGROUND: Neural tube defect (NTD) is a common birth defect causing much death in the world. Variants in VANGL1 lead to NTD and caudal regression syndrome. NTD displays a complex phenotype encompassing both genetic and environmental factors. METHODS: The fetus was diagnosed by prenatal ultrasound examination. Postnatal CT and autopsy were performed. Genetic testing was conducted in the family and Sanger sequencing was validated. Multiple prediction soft-wares were used to predict the pathogenicity of the variant. RESULTS: The VANGL1 gene variant c.1151C>G (P384R) was detected in a fetus diagnosed with tethered spinal cord and sacrococcygeal lipoma. The VANGL1 variant c.1151C>G (P384R) was reported in a Klippel-Feil syndrome patient. The VANGL1 variant was validated in the trio-family but the mother showed no abnormalities. CONCLUSION: Overall, this study presents fetal NTD caused by the same VANGL1 variant found in a Klippel-Feil syndrome patient with complete clinical information of prenatal ultrasound, postnatal CT, and genetic results as early as 25 GW. Our study not only expands the VANGL1 mutational spectrum but also sheds light on the important role of the VANGL1 P384R variant in human development.

Rare cause of paraparesis in a young man: cervico-dorsal neurenteric cysts associated with Klippel-Feil syndrome.

Klippel-Feil syndrome is an entity presenting with short neck, low hairline and reduced range of motion of cervical spine. Neurenteric cyst is a congenital abnormality, in which mucus-secreting epithelium of the gastrointestinal tract is seen in the spinal axis. The association of a neurenteric cyst with Klippel-Feil syndrome has been reported very rarely. We report the case of a young man, affected by Klippel-Feil syndrome, who presented with bilateral paraplegia. Imaging of the spine revealed features suggestive of cervico-dorsal neurenteric cyst. Subsequently, surgical resection of the cysts was done, which resulted in resolution of the symptoms.

[Clinical Characteristics and Genetic Analysis of Klippel-Feil Syndrome].

Objective To summarize clinical characteristics and investigate possible pathogenic gene of Klippel-Feil syndrome(KFS)by the self-designed multigene panel sequencing,so as to decipher the molecular basis for early diagnosis and targeted therapy.Methods From January 2015 to December 2018,we consecutively recruited 25 patients who were diagnosed with KFS in Peking Union Medical College Hospital.The demographic information,clinical manifestations,physical examination and radiological assessments were analyzed.Multigene panel sequencing was performed after DNA extraction from peripheral blood.The possible pathogenic mutations of KFS were explored on the basis of bioinformatics analysis.Results The KFS cohort consisted of 25 patients,including 15 males and 10 females,with a mean age of(12.9±7.3)years.Limited cervical range of motion was the most common clinical feature(12 cases,48%).Based on the Samartzis classification,the proportion of patients suffered from short neck(P=0.031)and limited cervical range of motion(P=0.026)in type Ⅲ KFS was significantly higher than that in type Ⅱ and type Ⅰ KFS.Panel sequencing detected a total of 11 pathogenic missense mutations in eight patients,including COL6A1,COL6A2,CDAN1,GLI3,FLNB,CHRNG,MYH3,POR,and TNXB.There was no pathogenic mutation found in five reported pathogenic genes(GDF6,MEOX1,GDF3,MYO18B and RIPPLY2)associated with KFS.Conclusions Our study has shown that patients with multiple contiguous cervical fusions are more likely to manifest short neck,limited cervical range of motion,and clinical triad.Therefore,these patients need additional attention and follow-up.Our analysis highlights novel KFS-related genetic variants,such as COL6A and CDAN1,extending the spectrum of known mutations contributing to this syndrome and providing a basis for elucidating the pathogenesis of KFS.

Prenatal diagnosis of Sprengel's deformity in a patient with Klippel-Feil Syndrome.

We present a case of Klippel-Feil Syndrome, a congenital skeletal defect where multiple cervical vertebral bodies are fused. Klippel-Feil Syndrome has multiple associated anomalies, with a notable one being Sprengel's deformity. In this case, the patient was given a diagnosis of Klippel-Feil Syndrome prenatally after suspected cervical vertebrae fusion and Sprengel's deformity were seen on both fetal magnetic resonance imaging (MRI) and ultrasound. Prenatal diagnosis of Sprengel's deformity has been reported once in the literature. In this report, we present imaging findings of Sprengel's deformity seen in association with Klippel-Feil Syndrome using a combination of fetal ultrasound and MRI.

Cervical myelopathy in a child with Sprengel shoulder and Klippel-Feil syndrome.

PURPOSE: Sprengel shoulder, Klippel-Feil syndrome and congenital scoliosis are associated conditions. Cervical myelopathy in a child due to a concomitant omovertebral bar causing posterior cord compression and a hypermobile cervical disc protrusion adjacent to fused cervical segments causing anterior compression at the same level is very rare. We report the presentation, findings, surgical management and results of treatment in such a child. METHODS: A 9-year-old girl with Sprengel shoulder presented with cervical myelopathy (Frankel D). Imaging revealed a bony omovertebral bar connected to the left scapula compressing the spinal cord posteriorly through a lamina defect at C5 resulting in significant cervical stenosis. A hypermobile disc protrusion adjacent to congenitally fused segments resulted in anterior compression at the same level. She was treated surgically with cervical laminectomy and instrumented fusion, excision of the omovertebral bar and modified Woodward procedure for the left Sprengel shoulder. RESULTS: At 2 year follow-up, she had improved neurologically (Frankel E) and there was improved shoulder symmetry and abduction. MRI showed resolution of cervical stenosis. Although there was no significant progression of congenital scoliosis, it will need to be monitored. CONCLUSIONS: Cervical myelopathy due to an omovertebral bar and cervical disc protrusion in a child with Klippel-Feil syndrome and Sprengel shoulder is a rare presentation and can be treated with a single posterior approach addressing both pathologies.

Congenital Fusion of Dens to T3 Vertebra in Klippel-Feil Syndrome.

BACKGROUND: Patients with Klippel-Feil syndrome may present with neurologic complaints such as neck pain, radiculopathy and gait instability. Here we describe surgical management of a patient with congenital fusion of the occipital-cervical region and also block circumferential fusion of dens to T3 with spinal cord compression. This report is the first of its kind with such extensive fusion. CASE DESCRIPTION: Our patient was a 56 year-old female, who presented with neck pain and tingling in all extremities. On exam, she had a short neck, prominent jaw with extremely limited range of motion in neck and features of myelopathy. CT showed fusion of the dens to T3 vertebrae. Patient underwent sub-occipital craniectomy, C1 laminectomy and Occiput to T5 posterior fixation and fusion with neurologic improvement. CONCLUSION: This is the first reported case of Klippel-Feil syndrome with fusion of all cervical vertebrae down to T3. We recommend surgery for advanced cases of myelopathy or radiculopathy due to stenosis and spinal instability.

Sprengel Deformity: Comprehensive Evaluation of Concomitant Spinal and Extraspinal Anomalies in 90 Patients.

STUDY DESIGN: A retrospective, case series. OBJECTIVE: The aim of this study is to evaluate the concomitant anomalies in patients with Sprengel deformity (SD). SUMMARY OF BACKGROUND DATA: SD is the most common congenital anomaly of the shoulder. One or more associated anomalies may coexist in SD patients, similar to congenital scoliosis (CS); however, these anomalies and their relationship have not been studied in detail previously. METHODS: SD patients who have applied to our institution between 2005 and 2019 were retrospectively reviewed. The patients were evaluated clinically and radiologically. The patients were divided in two groups as SD patients with CS and without CS, to analyze if these anomalies are present due to CS or SD. Physical examination findings, MRI, CT, and USG reports were analysed for accompanying pathologies. Patients with missing data were excluded. Student-t and Fisher's exact tests were used to compare the groups. Significance value was set as p = 0.05. RESULTS: Ninety patients met inclusion criteria. The most common spinal anomaly was omovertebra, followed by spina bifida and Klippel-Feil. Tethered cord and diastematomiyelia were associated with CS (P = 0.0026 and P = 0.0057, respectively). The most common extra-skeletal anomaly was rib anomalies, followed by urinary and cardiac system anomalies. Rib anomalies were associated with CS (P = 0.00001). CONCLUSION: Concomitant anomalies may accompany SD. The prognosis of SD may be affected by these anomalies. Therefore, patients should be evaluated for possible coexistent congenital anomalies. LEVEL OF EVIDENCE: 4.

The mutational burden and oligogenic inheritance in Klippel-Feil syndrome.

BACKGROUND: Klippel-Feil syndrome (KFS) represents a rare anomaly characterized by congenital fusion of the cervical vertebrae. The underlying molecular etiology remains largely unknown because of the genetic and phenotypic heterogeneity. METHODS: We consecutively recruited a Chinese cohort of 37 patients with KFS. The clinical manifestations and radiological assessments were analyzed and whole-exome sequencing (WES) was performed. Additionally, rare variants in KFS cases and controls were compared using genetic burden analysis. RESULTS: We primarily examined rare variants in five reported genes (GDF6, MEOX1, GDF3, MYO18B and RIPPLY2) associated with KFS and detected three variants of uncertain significance in MYO18B. Based on rare variant burden analysis of 96 candidate genes related to vertebral segmentation defects, we identified BAZ1B as having the highest probability of association with KFS, followed by FREM2, SUFU, VANGL1 and KMT2D. In addition, seven patients were proposed to show potential oligogenic inheritance involving more than one variants in candidate genes, the frequency of which was significantly higher than that in the in-house controls. CONCLUSIONS: Our study presents an exome-sequenced cohort and identifies five novel genes potentially associated with KFS, extending the spectrum of known mutations contributing to this syndrome. Furthermore, the genetic burden analysis provides further evidence for potential oligogenic inheritance of KFS.

Congenital posterior cervical spine malformation due to biallelic c.240-4T>G RIPPLY2 variant: A discrete entity.

The clinical and radiological spectrum of spondylocostal dysostosis syndromes encompasses distinctive costo-vertebral anomalies. RIPPLY2 biallelic pathogenic variants were described in two distinct cervical spine malformation syndromes: Klippel-Feil syndrome and posterior cervical spine malformation. RIPPLY2 is involved in the determination of rostro-caudal polarity and somite patterning during development. To date, only four cases have been reported. The current report aims at further delineating the posterior malformation in three new patients. Three patients from two unrelated families underwent clinical and radiological examination through X-ray, 3D computed tomography and brain magnetic resonance imaging. After informed consent was obtained, family-based whole exome sequencing (WES) was performed. Complex vertebral segmentation defects in the cervico-thoracic spine were observed in all patients. WES led to the identification of the homozygous splicing variant c.240-4T>G in all subjects. This variant is predicted to result in aberrant splicing of Exon 4. The current report highlights a subtype of cervical spine malformation with major atlo-axoidal malformation compromising spinal cord integrity. This distinctive mutation-specific pattern of malformation differs from Klippel-Feil syndrome and broadens the current classification, defining a sub-type of RIPPLY2-related skeletal disorder. Of note, the phenotype of one patient overlaps with oculo-auriculo-vertebral spectrum disorder.

Bilateral Multilevel Cervical Rib and Bilateral Omovertebra in Klippel-Feil Syndrome.

BACKGROUND: Klippel-Feil syndrome was first described in 1912; a short neck, low posterior hairline, and decreased cervical joint range of motion are the classical triad of this disease. In this syndrome, which is rarely observed, the characteristics that have been reported include the following: scoliosis; Sprengel deformity; cervical rib; ear, nose, oral, and laryngeal abnormalities; structural abnormalities of the urinary system; and congenital heart diseases. However, bilateral omovertebra and bilateral multilevel cervical ribs have not been reported. CASE DESCRIPTION: We aimed to present this rare syndrome via radiologic findings from cases with bilateral multilevel cervical rib and bilateral omovertebra. CONCLUSIONS: Cases of Klippel-Feil syndrome may be accompanied by multiple abnormalities. We want to highlight the need for detailed examination of patients and lifestyle modification at an early age, before symptom appearance, as well as adaptation to habitual exercise.

Intrathoracic bifurcation of the left common carotid artery associated with rib fusion and Klippel-Feil syndrome.

Common carotid artery usually bifurcates at the superior border of thyroid cartilage, corresponding to the C3-4 junction, however bifurcation level may vary. Common carotid bifurcation may have rare variations like separate origins of left internal and external carotid arteries from aortic arch, or bifurcation of common carotid artery within thoracic cavity. Intrathoracic carotid bifurcation is a rare variation with limited number of cases reported. The occurrence of a low carotid bifurcation seems to be embryologically related to the persistence of the ductus caroticus. Additionally, intrathoracic carotid bifurcation can be accompanied by findings of Klippel-Feil syndrome. Herein, we present imaging findings of an incidentally detected intrathoracic left common carotid artery bifurcation in a pediatric patient accompanied by fusion of the cervical vertebrae and ribs.