Duplication of right vertebral artery in Klippel-Feil anomaly.

The duplicated origin of the vertebral artery (VA) is an uncommon anatomical variant, which is generally identified incidentally during angiography and can be misdiagnosed as dissection in the setting of posterior circulation stroke. Here, we describe a case of the right V1 VA duplication with embryological aspects in a patient with Klippel-Feil anomaly, which was diagnosed during preoperative evaluation. Surgeons must be aware to avoid vascular injury from a duplicated VA before head-neck and spinal surgery.

A Novel Technique for Basilar Invagination Treatment in a Patient with Klippel-Feil Syndrome: A Clinical Example and Brief Literature Review.

Objectives and Background: To present a novel technique of treatment for a patient with basilar invagination. Basilar invagination (BI) is a congenital condition that can compress the cervicomedullary junction, leading to neurological deficits. Severe cases require surgical intervention, but there is debate over the choice of approach. The anterior approach allows direct decompression but carries high complication rates, while the posterior approach provides indirect decompression and offers good stability with fewer complications. Materials and Methods: A 15-year-old boy with severe myelopathy presented to our hospital with neck pain, bilateral upper limb muscle weakness, and hand numbness persisting for 4 years. Additionally, he experienced increased numbness and gait disturbance three months before his visit. On examination, he exhibited hyperreflexia in both upper and lower limbs, muscle weakness in the bilateral upper limbs (MMT 4), bilateral hypoesthesia below the elbow and in both legs, mild urinary and bowel incontinence, and a spastic gait. Radiographs revealed severe basilar invagination (BI). Preoperative images showed severe BI and that the spinal cord was severely compressed with odontoid process. Results: The patient underwent posterior surgery with the C-arm free technique. All screws including occipital screws were inserted into the adequate position under navigation guidance. Reduction was achieved with skull rotation and distraction. A follow-up at one year showed the following results: Manual muscle testing results and sensory function tests showed almost full recovery, with bilateral arm recovery (MMT 5) and smooth walking. The cervical Japanese Orthopedic Association score of the patient improved from 9/17 to 16/17. Postoperative images showed excellent spinal cord decompression, and no major or severe complications had occurred. Conclusions: Basilar invagination alongside Klippel-Feil syndrome represents a relatively uncommon condition. Utilizing a posterior approach for treating reducible BI with a C-arm-free technique proved to be a safe method in addressing severe myelopathy. This novel navigation technique yields excellent outcomes for patients with BI.

Mitral Valve Regurgitation in Klippel-Feil Syndrome With Related Thoracic Deformity.

Klippel-Feil syndrome, characterized by congenital fusion of any 2 or more cervical vertebrae, is a rare disorder in which skeletal and other organ system-related abnormalities have been reported. This article reports a case of mitral valve regurgitation in a patient with Klippel-Feil syndrome and related thoracic deformity who underwent mitral valvuloplasty. Postoperatively, the mitral valve regurgitation disappeared, and there has been no recurrence for 3 years. This case highlights mitral valvuloplasty via median sternotomy as an excellent treatment for mitral valve regurgitation in a patient with thoracic deformity related to Klippel-Feil syndrome.

Tetraparesis following thoracic spine surgery in a patient with Klippel-Feil syndrome and ABCB4 mutation: a case report.

BACKGROUND: Klippel-Feil syndrome is a rare condition described in 1912 by Maurice Klippel and André Feil. It is defined as a congenital cervical fusion of at least two vertebrae, associated with a classical triad of clinical signs: short neck, low posterior hairline, and limited range of movement. However, Klippel-Feil syndrome manifests with a vast spectrum of phenotypes, ranging from no symptoms to complete triad, with or without other associated malformations. Most commonly, CCF results from sporadic mutations, even though autosomal recessive, autosomal dominant, or even X-linked inheritance can be detected. The ATP-binding cassette subfamily B member 4 is only expressed in the liver and is involved in biliary phospholipid secretion. The clinical spectrum includes various hepatobiliary pathologies, including low phospholipid-associated cholelithiasis, and has never been associated with musculoskeletal anomalies. CASE PRESENTATION: A 55-year-old male Caucasian patient presenting with low phospholipid-associated cholelithiasis syndrome with ATP-binding cassette subfamily B member 4 mutation and liver cirrhosis was referred to our clinic for a liver transplant. A period of 6 months before, the patient underwent a T7-T9 posterior fixation for a T8 osteoporotic fracture. Postoperatively, he was tetraparetic, whereas he was neurologically intact before the operation. At admission to our hospital, he was still tetraparetic and presented with clinical signs of cervical myelopathy. Moreover, he suffered a limitation of cervical range of motion in all directions, short neck, and low posterior hairline. Imaging showed multiple cervical and thoracic vertebral bodies fusion, as well as cervical spine stenosis. Based on the available data, we diagnosed a type 3 Klippel-Feil syndrome according to Samartzis' classification. CONCLUSIONS: The heterogeneity of KFS and the various potential hereditary links that are known indicate that it is important to highlight all potential cases related to known genetic defects. At present, no association between ATP-binding cassette subfamily B member 4 mutation and congenital cervical fusions has been reported. The other important clinical focus of this case is the appearance of spontaneous tetraparesis after thoracic spine surgery. This mechanism remains unclear, but considering different spinal anatomy it might have been due to difficult intubation and patient's positioning during his previous operation.

Brown Sequard syndrome in a patient with Klippel-Feil syndrome following minor trauma: a case report and literature review.

BACKGROUND: There are some cases of Klippel-Feil syndrome with spinal cord injury in clinical work. However, there is no literature report on Brown-Sequard syndrome after trauma. We report a case of Brown-Sequard syndrome following minor trauma in a patient with KFS type III. Her Brown-Sequard syndrome is caused by Klippel-Feil syndrome. CASE PRESENTATION: We found a 38-year-old female patient with KFS in our clinical work. She was unconscious on the spot following a minor traumatic episode. After treatment, her whole body was numb and limb activity was limited. Half an hour later, she felt numb and weak in the right limb and weak in the left limb. She had no previous hypertension, diabetes, or coronary heart disease. After one-month treatment of medication, hyperbaric oxygen, rehabilitation, and acupuncture in our hospital, her muscle strength partially recovered, but the treatment effect was still not satisfactory. Then, she underwent surgical treatment and postoperative comprehensive treatment, and rehabilitation training. She was able to take care of herself with assistance, and her condition improved from grade B to grade D according to the ASIA (ASIA Impairment Scale) classification. CONCLUSION: KFS, also known as short neck deformity, is a kind of congenital deformity characterized by impaired formation and faulty segmentation of the cervical spine, often associated with abnormalities of other organs. The cervical deformity in patients with KFS can alter the overall mechanical activity of the spine, as well as the compensatory properties of the spine for decelerating and rotatory forces, thus increasing the chance of spinal cord injury (SCI) following trauma. Many mechanisms can make patients more susceptible to injury. Increased range of motion of the segment adjacent to the fused vertebral body may lead to slippage of the adjacent vertebral body and altered disc stress, as well as cervical instability. SCI can result in complete or incomplete impairment of motor, sensory and autonomic nervous functions below the level of lesion. This woman presented with symptoms of BSS, a rare neurological disorder with incomplete SCI. Judging from the woman's symptoms, we concluded that previously she had KFS, which resulted in SCI without fracture and dislocation following minor trauma, with partial BSS. After the comprehensive treatment of surgery, hyperbaric oxygen, rehabilitation therapy, and neurotrophic drugs, two years later, we found her symptoms significantly improved, with ASIA Impairment Scale from grade B to grade D, and her ability to perform activities of daily living with aids.

Transmandibular Cervical Corpectomy for Persistent Spinal Cord Compression in a Patient With Klippel-Feil Syndrome: A Technical Note and Systematic Review.

BACKGROUND: Few studies have described a transmandibular approach for decompression in a patient with Klippel-Feil syndrome (KFS) for cervical myelopathy. OBJECTIVE: To describe the transmandibular approach in a KFS patient with cervical myelopathy and to perform a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. METHODS: A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Embase and PubMed databases were searched from January 2002 to November 2022 for articles examining patients with KFS undergoing cervical decompression and/or fusion for cervical myelopathy and/or radiculopathy were included. Articles describing compression due to nonbony causes, lumbar/sacral surgery, nonhuman studies, or symptoms only from basilar invagination/impression were excluded. Data collected were sex, median age, Samartzis type, surgical approach, and postoperative complications. RESULTS: A total of 27 studies were included, with 80 total patients. Thirty-three patients were female, and the median age ranged from 9 to 75 years. Forty-nine patients, 16 patients, and 13 patients were classified as Samartzis Types I, II, and III, respectively. Forty-five patients, 21 patients, and 6 patients underwent an anterior, posterior, and combined approach, respectively. Five postoperative complications were reported. One article reported a transmandibular approach for access to the cervical spine. CONCLUSION: Patients with KFS are at risk of developing cervical myelopathy. Although KFS manifests heterogeneously and may be treated through a variety of approaches, some manifestations of KFS may preclude traditional approaches for decompression. Surgical exposure through the anterior mandible may prove an option for cervical decompression in patients with KFS.

Klippel-Feil Syndrome Associated with Renal and Cardiac Anomalies in an Infant: A Case Report.

Klippel-Feil syndrome is a rare congenital bone disorder characterised by a triad of short neck, low posterior hairline and limited lateral bending of the neck with an annual incidence of 1 in 40,000 live births. It has remained an obscure term in the medical literature because of its variability in presentation and wide spectrum of anomalies involving multiple organ systems. It is unusual to find a case that has all three classical triad features. Here, we present a case of a 9-month-old infant who manifests not only all three classical triad features associated with Klippel-Feil syndrome but also demonstrates the presence of congenital heart disease, scoliosis, and renal ectopia. An early comprehensive evaluation of a suspected case is essential for diagnosis and counselling which impacts its prognosis, helps minimize social stigma and affords parents the opportunity to consider cosmetic surgery as an option, should they choose to pursue it. Keywords: case reports; congenital; heart diseases; Klippel-Feil syndrome; scoliosis.

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.

Surgical Management Of Irreducible Atlanto-Axial Dislocation With OS Odontoideum And Klippel-Feil Syndrome.

Klippel-Feil syndrome (KFS) is the congenital fusion of two or more cervical vertebrae which is often associated with various other abnormalities in the cervical spine. Involvement the upper cervical segments leads to atlanto-axial instability which manifests as progressive neurological symptoms due to compression on the spinal cord. These cases pose a surgical challenge due the abnormal and unique anatomy of each patient. A 37-year-old patient presented with neck pain and cervical myelopathy due to a posterior subluxation of C2-3 fused segment over C4-6 fused segment. The patient had an os odontoideum, incomplete posterior arch of C1, anomalous course of vertebral artery and C3 hemi-vertebra. The patient was successfully managed with transoral odontoidectomy and occipeto-cervical fusion. Irreducible atlanto-axial dislocation in a patient with an abnormal upper cervical spine anatomy may require transoral decompression followed by posterior fusion.

[Research on effectiveness of occipito-odontoid angle in predicting dysphagia after occipitocervical fusion in patients with C 2, 3 Klippel-Feil syndrome].

Objective: To introduce a new occipitocervical angle parameter, occipito-odontoid angle (O-Da), for predicting dysphagia after occipitocervical fusion (OCF) in patients with C 2, 3 Klippel-Feil syndrome (KFS) and analyze its effectiveness. Methods: A total of 119 patients met selective criteria between April 2010 and November 2019 were retrospectively included as the study subjects. There were 56 males and 63 females. The age ranged from 14 to 76 years, with a median age of 51 years. There were 44 cases of basilar invagination and 75 cases of atlantoaxial subluxation. Forty patients were combined with C 2, 3 KFS. Seven patients underwent anterior decompression combined with posterior OCF and 112 patients underwent posterior OCF. The fixed segments were O-C 2 in 36 cases, O-C 3 in 51 cases, O-C 4 in 25 cases, and O-C 5 in 7 cases. All patients were followed up 21-136 months, with a median time of 79 months. The lateral cervical X-ray films before operation and at last follow-up were used to measure the occipital to C 2 angle (O-C 2a), the occipital and external acoustic meatus to axis angle (O-EAa), the occipital protuberance to axial angle (Oc-Axa), the O-Da, and the narrowest oropharyngeal airway space (nPAS). The differences of the above parameters between the last follow-up and the preoperative values were calculated (represented as dO-C 2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS). Patients were divided into two groups according to whether they suffered dysphagia after operation, and the differences in clinical data and radiographic parameters were compared between the two groups. The correlation between occipitocervical angle parameters and nPAS in 40 patients with C 2, 3 KFS was analyzed respectively. In addition, sensitivity and specificity analyses were used to assess the effectiveness of dO-Da≤-5° for the prediction of postoperative dysphagia. Results: Thirty-one patients (26.1%) suffered dysphagia after OCF (dysphagia group), including 10 patients with C 2, 3 KFS; no dysphagia occurred in 88 patients (non-dysphagia group). There was no significant difference in age, follow-up time, fixed segment, proportion of patients with rheumatoid arthritis, proportion of patients with atlantoaxial subluxation, and proportion of patients with C 2, 3 KFS between the two groups ( P>0.05). The proportion of female patients was significantly higher in dysphagia group than in non-dysphagia group ( χ 2=7.600, P=0.006). The difference in preoperative O-C 2a between the two groups was significant ( t=2.528, P=0.014). No significant differences were observed in preoperative O-EAa, Oc-Axa, O-Da, and nPAS ( P>0.05). There was no significant difference in dO-C 2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS between the two groups ( P>0.05). The dO-C 2a, dO-EAa, dOc-Axa, and dO-Da were positively correlated with dnPAS in 40 patients with C 2, 3 KFS ( r=0.604, P<0.001; r=0.649, P<0.001; r=0.615, P<0.001; r=0.672, P<0.001). Taking dO-Da≤-5° as the standard, the sensitivity and specificity of dO-Da to predict postoperative dysphagia in patients with C 2, 3 KFS were 80.0% (8/10) and 93.3% (28/30), respectively. Conclusion: The dO-Da is a reliable indicator for predicting dysphagia after OCF in patients with C 2, 3 KFS.

A rare case of difficult airway management in a Klippel-Feil syndrome pediatric patient with osseous torticollis undergone orthopedic surgery : Difficult airway in pediatric patient with torticollis.

BACKGROUND: Orthopedic surgery for cervical torticollis poses potential threat to airway management both in tracheal intubation and extubation. Klippel-Feil syndrome (KFS) is a complex syndrome of osseous and visceral anomalies. The anatomical characteristics of KFS might have significant implications for airway management. CASE PRESENTATION: This is a rare case of an 8-year-old boy presenting with osseous torticollis, congenital occipito-atlantal deformity, congenital basilar invagination and KFS undergone elective torticollis correction surgery. Though with difficulty, tracheal intubation was successfully performed. Extubation failed twice on postoperative day 2 and 10, and required tracheostomy. Based on radiological findings, we speculated that prolonged airway edema accounted for the main reason of the failed extubation, the hypertrophic tonsil and occipito-cervical fusion resulted in reduced oropharyngeal space and limited cervical range of motion. Moreover, the Chiari malformation and KFS complicated the airway condition and lead to prolonged airway obstruction. The tracheostomy casing was removed 1 month later. CONCLUSIONS: Cautions should be taken in extubation of pediatric patients undergone major osseous torticollis surgery. Reintubation should be prepared in case of failed extubation. Severe post-operative airway edema, complicated with hypertrophic tonsil, the structural abnormalities in the oropharyngeal cavity, and occipito-cervical deformities constituted the decreased oropharyngeal space and resulted in failed extubation. For severe airway compromise and prolonged intubation, tracheostomy should be considered.

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.

Further delineation of MYO18B-related autosomal recessive Klippel-Feil syndrome with myopathy and facial dysmorphism.

Klippel-Feil syndrome 4 (KFS4; MIM# 616549) is an autosomal recessive disorder caused by biallelic pathogenic variants in MYO18B and comprises, in addition to Klippel-Feil anomaly (KFA), nemaline myopathy, facial dysmorphism, and short stature. We aim to outline the natural history of KFS4 and provide an updated description of its clinical, radiological, laboratory, and molecular findings. We comprehensively analyzed the medical records of 6 Saudi and 1 American patients (including 5 previously unpublished cases) with a molecularly confirmed diagnosis of KFS4. All patients had myopathy of varying severity that followed a slowly progressive or non-progressive course, affecting primarily the proximal musculature of the lower limb although hand involvement with distal arthrogryposis and abnormal interphalangeal creases was also observed. KFA and characteristic dysmorphic features, including ptosis and bulbous nose, were observed in all but two patients. The causal MYO18B variants were a founder NM_032608.5:c.6905C>A; p.(Ser2302*) variant in the Saudi patients (P1-P6) and a novel MYO18B homozygous variant (c.6660_6670del;p.[Arg2220Serfs*74]) in the American Caucasian patient (P7). We report the phenotypic and genetic findings in seven patients with KFS4. We describe the natural history of this disease, confirm myopathy as a universal feature and describe its pattern and progression, and note interesting differences between the phenotypes observed in patients with KFA and those without.

Intervertebral Disc Calcification and Klippel-Feil Syndrome.

Intervertebral disc calcification is rare in the pediatric population and is associated with sudden neurological manifestations. Although commonly symptomatic, conservative management yields excellent prognosis in the vast majority of cases. The following case illustrates the finding of intervertebral disc calcification in a patient with vertebral body segmentation anomaly consistent with Klippel-Feil Syndrome. As both entities are associated with potential neurological sequelae, this case of coexistent pathologies highlights the importance of recognizing the potential presence of intervertebral disc calcifications in pediatric Klippel-Feil Syndrome patients.

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.

Surgical Treatment for Central Sleep Apnea due to Occipitocervical Compression Myelopathy in a Patient with Klippel-Feil Syndrome.

BACKGROUND: Central sleep apnea (CSA) due to occipitocervical compression myelopathy is an extremely rare condition. Here we report a case of surgical treatment for CSA due to occipitocervical compression myelopathy in a patient with Klippel-Feil syndrome. CASE DESCRIPTION: A 60-year-old man had become aware of a gradually progressive clumsiness and gait disturbance without any cause of injury 5 years before. He had complicated respiratory discomfort during sleep for the previous month and visited our hospital. Neurologic examination revealed severe myelopathy. Polysomnography showed CSA and Cheyne-Stokes respiration. Imaging findings showed C2-3 vertebral fusion and severe spinal cord compression caused by hypoplasia of the C1 posterior arch complicated by an anomaly of the vertebral artery. We diagnosed the patient with CSA due to occipitocervical compression myelopathy complicated by Klippel-Feil syndrome. After a simulation using a full-scale 3-dimensional model, resection of the C1 posterior arch and C4-5 laminoplasty was performed. After surgery, both clumsiness and gait disturbance gradually improved. Polysomnography 1 month after surgery showed that the CSA and the Cheyne-Stokes respiration disappeared. CONCLUSIONS: Although a recent report has indicated the cause of sleep apnea in patients with rheumatoid arthritis and occipitocervical disorders as obstructive sleep apnea, a significant improvement of CSA was observed with decompression surgery in this case. Appropriate surgical planning resulted in a favorable outcome.

Klippel-Feil Syndrome With Auxiliary Anterior Cervical Meningomyelocele and Thoracic Syringomyelia: A Case Report.

STUDY DESIGN: Case report. OBJECTIVE: Since this is the first ever case of a male patient with Klippel-Feil syndrome (KFS) with anterior cervical meningomyelocele and syringomyelia. All four previously reported cases were female patients. This makes this case unique. SUMMARY OF BACKGROUND DATA: KFS with auxiliary anterior cervical meningomyelocele is a rare entity. To the best of our knowledge so far only four cases are reported. METHODS: A 22-year-old male patient was presented to neurology outpatient department with 2-year history of left hand paresthesia and progressive weakness. The diagnostic evaluation showed KFS with auxiliary anterior cervical meningomyelocele and thoracic syringomyelia. RESULTS: Patient was sent to neurosurgery department for intervention. After discussing the possible risks and complications of intervention he opted for conservative therapy and declined the surgery. CONCLUSION: The paucity of data is the key reason for any recommended protocol for management of such patients but the available literature recommends neurosurgical intervention in symptomatic patients. LEVEL OF EVIDENCE: 5.

Endoscopic Endonasal Approach for Urgent Decompression of Craniovertebral Junction in Syringobulbia.

BACKGROUND: Syringobulbia is an uncommon lesion that occurs in the central nervous system; it is often defined as a pathologic cavitation in the brainstem. The cases with partial blockage of the cerebrospinal fluid pathways at the level of the foramen magnum are more common and the most important group. The most common treatment of syringobulbia is craniovertebral decompression. CASE DESCRIPTION: This paper reports a case of a symptomatic syringobulbia in which an urgent endoscopic endonasal approach to the craniovertebral junction (CVJ) was done to limit bulbo-medullary compression and rapid neurologic deterioration. A 69-year-old man was admitted to the hospital because of acute onset of dysphonia, dysphagia, imbalance, and vomiting. Magnetic resonance imaging revealed a cystic lesion in the brainstem, suggestive of a syringobulbia in Klippel Feil syndrome with CVJ stenosis. CONCLUSIONS: This case report details the successful use of endoscopic endonasal anterior decompression to treat syringobulbia, and adds to the growing literature in support of the endonasal endoscopic approach as a safe and feasible means for decompressing the craniocervical junction, even in the setting of urgency. However, prudent patient selection, combined with sound clinical judgment, access to instrumentation, and intraoperative imaging cannot be overemphasized.

Expanding the clinical history associated with syndromic Klippel-Feil: A unique case of comorbidity with medulloblastoma.

Klippel-Feil syndrome (KFS) is an exceedingly rare constitutional disorder in which a paucity of knowledge exists about the disease and its associated morbidity and mortality. We present a 4-year-old male with KFS, who notably was also diagnosed with large-cell anaplastic medulloblastoma. We evaluated the genetic basis of co-occurring KFS and medulloblastoma and the role of MYO18B as related to medulloblastoma. Constitutional and somatic variant and copy number analyses were performed from DNA-based exome studies, along with RNA-sequencing of tumor tissue, to elucidate the genetic etiology of the co-existing disease states. We identified novel constitutional compound heterozygous frameshift variants (NM_032608.5: p.Leu2257SerfsTer16 and p.Arg2220SerfsTer74) each encoding a premature stop of translation in MYO18B, consistent with a diagnosis of KFS. We did not identify any somatic variants of known relevance or disease-relevant therapeutic targets in the tumor. The somatic copy number profile was suggestive of Group 3γ medulloblastoma. Relative to pediatric brain tumors, medulloblastoma, particularly, Group 3, had increased gene expression of MYO18B. In summary, coexisting constitutional and somatic diagnoses in this patient enabled the elucidation of the genetic etiology of KFS and provided support for the role of MYO18B in tumor suppression.