Klippel-Feil syndrome: Should additional examination be conducted?

PURPOSE: Klippel-Feil syndrome (KF) is a rare disease defined as single or multi-level cervical vertebra fusion. KF could be accompanied by other spinal anomalies or isolated, and in which case necessity of whole spine screening is not clearly known. KF is investigated in terms of prevalence, gender distribution, fusion types, and frequency of accompanying anomalies according to types of KF. METHODS: Approval from our hospital's ethics committee was received for this single-center, retrospective study. Considering the exclusion criteria among the 40,901 cervical spine MRIs, 40,450 patients were included in the study. It was re-evaluated for KF, fusion level, classification, cervical scoliosis, and other musculoskeletal and spinal anomalies. RESULTS: 125 (0.309%) of 40,450 patients is diagnosed with KF, which is more common in women (P < 0.001). Single fused segment 106 (84.8%), multilevel fused segments 8 (6.4%), contiguous fused segments 11 (8.8%) are observed. Upper level KF is detected in 13 (10.4%) patients. The frequency of additional anomaly is significantly higher in upper level KF compared to other level fusions (P < 0.001, Chi-square t). The cervical scoliosis is diagnosed 34 (27%). In KF patients with scoliosis, the frequency of additional anomalies was significantly higher (P < 0.001, Chi-square t). CONCLUSION: Klippel-Feil prevalence is 0.309%, it is frequently observed in women, and at C2-C3 level. Additional anomalies are especially associated with 'contiguous fused segments' and 'upper level' types. Klippel-Feil with scoliosis is an indicator of increased risk for associated anomalies, and examination of the whole spine is recommended.

[The multisystem deformities features of Klippel-Feil syndrome patients combined with congenital scoliosis].

Objective: To summarize the characteristics of multisystem deformities in patients with Klippel-Feil syndrome (KFS) combined with congenital scoliosis (CS). Methods: Within the framework of the "Deciphering Disorders Involving Scoliosis and Comorbidities (DISCO)" research collaboration, a retrospective analysis was conducted on patients diagnosed with KFS and CS at Peking Union Medical College Hospital between April 2005 and August 2022. Patient data, including imaging examinations and medical records, were collected to summarize the spinal and associated deformities. Results: A total of 82 KFS patients with concurrent CS were included, comprising 42 males and 40 females. The average age was (12.8±8.9) years. Among the KFS patients, there were 31 cases of Type Ⅰ, 12 cases of Type Ⅱ, and 39 cases of Type Ⅲ. The most common location for the major curve of scoliosis was the mid-thoracic segment (42 cases, 51.2%). Hemivertebrae deformities were most frequently observed in the upper thoracic segment (31 cases, 60.8%). There were no statistically significant differences in age, gender, major curve Cobb angle, or region of hemivertebrae occurrence among the different types of KFS (all P>0.05). Apart from spinal vertebral deformities, intraspinal deformities had the highest comorbidity rate (33 cases, 40.2%). The subjects were divided into two groups based on the presence or absence of intraspinal deformity (absence as group G0, presence as group G1), there was a statistically significant difference in the main Cobb angle [M(Q1, Q3)] between the two groups, which was 45.0° (27.5°, 62.0°) and 60.0° (37.5°, 83.5°), respectively (P=0.044). Additionally, a portion of the patients had concurrent cardiovascular system abnormalities (13 cases, 15.9%), craniofacial-ocular-auricular abnormalities (8 cases, 9.8%), genitourinary system abnormalities (7 cases, 8.5%), and gastrointestinal abnormalities (2 cases, 2.4%). Conclusions: Patients with KFS combined with CS commonly present with a major curve of spinal deformity in the mid-thoracic segment and often have comorbidities involving multiple systems. When combined with intraspinal anomalies, the major curve exhibits a greater degree of curvature.