Radiographic assessment of segmental motion at the atlantoaxial junction in the Klippel-Feil patient

Fragility of L5 Vertebral Fracture After Rod Fracture at the Lumbosacral Junction Following Long-Segment Spinal Fusion Surgery for Adult Spine Deformity

We report a case of vertebral fracture in a patient with rod fractures after adult spinal deformity surgery, which occurred at the same level as the rod fractures, even though intervertebral bone fusion in the fusion range had been achieved. A 77-year-old female underwent corrective spinal surgery for adult spinal deformity from T12 to the pelvis but had a subsequent uppermost instrumented vertebral fracture, resulting in pseudarthrosis and severe kyphosis. The patient underwent proximal fusion extension to the T4, which improved alignment. A right-sided rod fracture at the lumbosacral junction occurred after 18 months; however, it showed no symptoms. After a month, the patient experienced severe low back pain with left leg pain and was diagnosed with bilateral rod fractures associated with L5 hyperextension vertebral fracture. The patient underwent revision surgery to repair the fractured rods with a multiple-rod construct. Rod fractures can occur even when bone fusion is achieved within the fusion range. When rod fractures are detected at the lumbosacral junction even if the interbody fusion was achieved, a hyperextension vertebral fracture may occur.

Ethnic and Sex Diversity in Academic Plastic Surgery: A Cross-sectional Study

Ethnic, racial, and sex disparities continue to persist in medicine despite efforts to diversify the profession. In competitive surgical specialties such as plastic surgery, those disparities are particularly pronounced. This study aims to evaluate racial, ethnic, and sex diversity in academic plastic surgery.

Methods

We compiled a list of major plastic surgery professional societies, plastic surgery journal editorial boards, and plastic surgery accreditation boards to evaluate ethnic and sex diversity in society, research, and accreditation domains, respectively. Demographic data were collected and analyzed using the Mann-Whitney U test and the Kruskal-Wallis test.

Results

White individuals are significantly overrepresented across the professional and research domains, and Asian individuals are overrepresented in the professional domain when compared to non-white races. White individuals make up a total of 74% of the society domain, 67% of the research domain, and 86% of the accreditation domain when compared to all non-white surgeons. Male surgeons made up 79% of the society domain, 83% of the research domain, and 77% of the accreditation domain when compared to all non-male surgeons.

Conclusions

Ethnic, racial, and sex disparities persist in academic plastic surgery. This study, which looked at societies, editorial boards, and accreditation boards, demonstrated a persistent ethnic, racial, and sex homogeneity among leadership. Changes are required to continue to diversify the field and provide women and underrepresented minorities the tools needed to succeed.

Clinical and Surgical Characteristics of Patients with Atlantoaxial Dislocation in the Setting of "Sandwich Fusion": A Case-Control Study

BACKGROUND

Patients with "sandwich" fusion (concomitant C1 occipitalization and C2-C3 nonsegmentation), a subtype of Klippel-Feil syndrome, are at particular risk for developing atlantoaxial dislocation (AAD). However, the clinical and surgical characteristics of AAD in patients with sandwich fusion have not been clearly defined.

METHODS

A retrospective case-control study with a large sample size and a minimum 2-year follow-up was performed. From 2000 to 2018, 253 patients with sandwich AAD underwent a surgical procedure; these patients constituted the case group, and a matching number of patients with non-sandwich AAD were randomly selected to form the control group. Clinical data from electronic medical records and various imaging studies were analyzed and compared. The Japanese Orthopaedic Association (JOA) scale was used to evaluate neurological function.

RESULTS

Patients with sandwich AAD, compared with patients with non-sandwich AAD, had symptom onset at a younger age (34.8 compared with 42.8 years; p < 0.001) and had a higher likelihood for myelopathy (87.4% compared with 74.7%; p < 0.001). Patients with sandwich AAD had a higher incidence of lower cranial nerve palsy (7.9% compared with 0.0%; p < 0.001), a lower preoperative JOA score (13.4 compared with 14.2; p < 0.001), and higher incidences of accompanying Type-I Chiari malformation (20.9% compared with 1.2%; p < 0.001) and syringomyelia (21.3% compared with 1.6%; p < 0.001). Finally, patients with sandwich AAD had higher likelihoods of undergoing transoral release (28.5% compared with 5.1%; p < 0.001) and use of salvage fixation techniques (34.4% compared with 6.3%; p < 0.001), and had lower postoperative results for the JOA score (14.9 compared with 15.9; p < 0.001) and improvement rate (43.8% compared with 58.2%; p < 0.001).

CONCLUSIONS

Patients with sandwich AAD demonstrated distinct clinical manifestations. Versatility involving the use of various internal fixation techniques and transoral release procedures was frequently required in the surgical management of these patients, and meticulous and personalized preoperative planning would be of paramount importance.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A novel technique of transpedicular opening-wedge osteotomy for treatment of rigid kyphosis in patients with ankylosing spondylitis

BACKGROUND

To investigate the effectiveness and feasibility of a novel vertebral osteotomy technique, transpedicular opening-wedge osteotomy (TOWO) was used to correct rigid thoracolumbar kyphotic deformities in patients with ankylosing spondylitis (AS).

METHODS

Eighteen AS patients underwent TOWO to correct rigid thoracolumbar kyphosis. Radiographic parameters were compared before surgery, 1 week after surgery and at the last follow-up. The SRS-22 questionnaire was given before surgery and at the last follow-up to evaluate clinical improvement. The operating time, estimated blood loss and complications were analyzed.

RESULTS

The mean operating time and estimated blood loss were 236 min and 595 ml, respectively. The mean preoperative sagittal vertical axis (SVA), thoracic kyphosis (TK), pelvic tilt (PT) and thoracolumbar kyphosis (TLK) were 158.97 mm, 51.24 mm, 43.63 mm and 41.74 mm, respectively, and decreased to 66.72 mm, 35.96 mm, 27.21 mm and 8.67 mm at the last follow-up. The mean preoperative lumbar lordosis (LL) and sacral slope (SS) were 8.30 ± 24.43 mm and 19.67 ± 9.40 mm, respectively, which increased to 38.23 mm and 28.13 mm at the last follow-up. The mean height of the anterior column of osteotomized vertebrae increased significantly from 25.17 mm preoperatively to 37.59 mm at the last follow, but the height of the middle column did not change significantly. SRS-22 scores were improved significantly at the last follow-up compared with preoperatively. Solid bone union was achieved in all patients after 12 months of follow-up, and no screw loosening, screw removal or rod breakage was noticed at the last follow-up.

CONCLUSIONS

TOWO could achieve satisfactory kyphosis correction by opening the anterior column instead of vertebral body decancellation and posterior column closing, thus simplifying the osteotomy procedure and improving surgical efficacy.

Can C1 lateral mass and C3 pedicle screw fixation be used as an option for atlantoaxial reduction and stabilization in Klippel-Feil patients? A study of its morphological feasibility, technical nuances, and clinical efficiency

In Klippel-Feil patients with atlantoaxial dislocation, narrow C2 pedicles are often encountered preventing pedicle screw placement. Alternative techniques, including translaminar screws, pars screws, and inferior process screws could not achieve 3-column rigid fixation, and have shown inferior biomechanical stability. The present study aimed to evaluate the feasibility, safety, and efficacy of C3 pedicle screws (C3PSs) as an option for atlantoaxial stabilization in Klippel-Feil patients, and to introduce a freehand technique, the "medial sliding technique," for safe and accurate C3PS insertion. Thirty-seven Klippel-Feil patients with congenital C2-3 fusion who have received atlantoaxial fixation were reviewed. Preoperative CT and CT angiography were acquired to evaluate the feasibility of C3PS placement. C1 lateral mass and C3PS constructs were used for atlantoaxial stabilization. The "medial sliding technique" was introduced to facilitate C3PS insertion. Clinical outcomes and complications were evaluated, and screw accuracy was graded on postoperative CT scans. Morphological measurements showed that more than 80% C3 pedicles could accommodate a 3.5-mm screw. Fifty-eight C3PSs were placed in 33/37 patients using the medial sliding technique. Overall, 96.7% screws were considered safe and there was no related neurovascular complications; 27/33 patients exhibited neurological improvement and 30/33 patients had a solid bone fusion at an average 19.3-month follow-up. Therefore, the C3PS was a feasible option for atlantoaxial fixation in Klippel-Feil patients. The clinically efficiency of C3PS was satisfied with high fusion rates and low complications. The medial sliding technique we used could facilitate safe and accurate placement of C3PSs in Klippel-Feil patients with fused C2-3 vertebra.

Klippel-Feil Syndrome: Pathogenesis, Diagnosis, and Management

Klippel-Feil syndrome (KFS), or congenital fusion of the cervical vertebrae, has been thought to be an extremely rare diagnosis. However, recent literature suggests an increased prevalence, with a high proportion of asymptomatic individuals. Occurring as a sporadic mutation or associated with several genes, the pathogenesis involves failure of cervical somite segmentation and differentiation during embryogenesis. Most commonly, the C2-C3 and C5-C6 levels are involved. KFS is associated with other orthopaedic conditions including Sprengel deformity, congenital scoliosis, and cervical spine abnormalities, as well as several visceral pathologies. There are several classification systems, some based on the anatomic levels of fusion and others on its genetic inheritance. Management of patients with KFS primarily involves observation for asymptomatic individuals. Surgical treatment may be for neurologic complaints, correction of deformity, concomitant spinal anomalies, or for associated conditions and varies significantly. Participation in sports is an important consideration. Recommendations for contact sports or activities depend on both the level and the number of vertebrae involved in the fusion. A multidisciplinary team should be involved in the treatment plan and recommendations for complex presentations.

Retro-Odontoid Pseudotumor Without Radiographic Instability with Congenital C1 Assimilation and C2-C3 Fusion: A Case Report

CASE

The authors present a case of retro-odontoid pseudotumor (ROP) with congenital C1 assimilation and C2-C3 block vertebra without radiological instability who presented with cervical myelopathy with spastic quadriparesis. The patient was managed with occipitocervical fusion and C1 laminectomy. She had rapid neurological recovery in 3 months postoperatively and at 2 years had complete resolution of the retro-odontoid mass.

CONCLUSION

C1 assimilation without apparent radiographic instability as a cause of ROP is underappreciated. This case report and review of literature highlight that C1 assimilation and C2-C3 fusion can lead to ROP even in the absence of apparent radiographic instability with posterior atlantoaxial fusion alone providing good results.

Atlantoaxial dislocation with congenital "sandwich fusion" in the craniovertebral junction: a retrospective case series of 70 patients

Background

In the setting of congenital C1 occipitalization and C2–3 fusion, significant strain is placed on the atlantoaxial joint. Vertebral fusion both above and below the atlantoaxial joint (i.e., a “sandwich”) creates substantial instability. We retrospectively report on a case series of “sandwich fusion” atlantoaxial dislocation (AAD), describing the associated clinical characteristics and detailing surgical treatment. To the best of our knowledge, the present study is the largest investigation to date of this congenital subgroup of AAD.

Methods

Seventy consecutive patients with sandwich fusion AAD, from one senior surgeon, were retrospectively reviewed. The clinical features and the surgical treatment results were assessed using descriptive statistics. No funding sources or potential conflict of interest-associated biases exist.

Results

The mean patient age was 42.2 years (range: 5–77 years); 36 patients were male, and 34 were female. Fifty-eight patients (82.9%) had myelopathy, with Japanese Orthopaedic Association (JOA) scores ranging 4–16 (mean: 12.9). Cranial neuropathy was involved in 10 cases (14.3%). The most common presentation age group was 31 to 40 years (24 cases, 34.3%). Radiological findings revealed brainstem and/or cervical-medullar compression (58 cases, 82.9%), syringomyelia (16 cases, 22.9%), Chiari malformation (12 cases, 17.1%), cervical spinal stenosis (10 cases, 14.3%), high scapula deformity (1 case, 1.4%), os odontoideum (1 case, 1.4%), and dysplasia of the atlas (1 case, 1.4%). Computed tomography angiography was performed in 27 cases, and vertebral artery (VA) anomalies were identified in 14 cases (51.9%). All 70 patients underwent surgical treatment, without spinal cord or VA injury. Four patients (5.7%) suffered complications, including 1 wound infection, 1 screw loosening, and 2 cases of bulbar paralysis. In the 58 patients with myelopathy, the mean JOA score increased from 12.9 to 14.5. The average follow-up time was 50.5 months (range: 24–120 months). All 70 cases achieved solid atlantoaxial fusion at the final follow-up.

Conclusions

Sandwich fusion AAD, a unique subgroup of AAD, has distinctive clinical features and associated malformations such as cervical-medullar compression, syringomyelia, and VA anomalies. Surgical treatment of AAD was associated with myelopathy improvement and minimal complication occurrence.

Klippel Feil Syndrome: Clinical Phenotypes Associated With Surgical Treatment

STUDY DESIGN

Retrospective study.

OBJECTIVE

To define distinct Klippel-Feil syndrome (KFS) patient phenotypes that are associated with the need for surgical intervention.

SUMMARY OF BACKGROUND DATA

KFS is characterized by the congenital fusion of cervical vertebrae; however, patients often present with a variety of other spinal and extraspinal anomalies suggesting this syndrome encompasses a heterogeneous patient population. Moreover, it remains unclear how the abnormalities seen in KFS correlate to neurological outcomes and the need for surgical intervention.

METHODS

Principal component (PC) analysis was performed on 132 KFS patients treated at a large pediatric hospital between 1981 and 2018. Thirty-five variables pertaining to patient/disease-related factors were examined. Significant PCs were included as independent variables in multivariable logistic regression models designed to test associations with three primary outcomes: cervical spine surgery, thoracolumbar/sacral spine surgery, and cranial surgery.

RESULTS

Fourteen significant PCs accounting for 70% of the variance were identified. Five components, representing four distinct phenotypes, were significantly associated with surgical intervention. The first group consisted of predominantly subaxial cervical spine fusions, thoracic spine abnormalities and was associated with thoracolumbar/sacral spine surgery. The second group was largely represented by axial cervical spine anomalies and had high association with cervical subluxation and cervical spine surgery. A third group, heavily represented by Chiari malformation, was associated with cranial surgery. Lastly, a fourth group was defined by thoracic vertebral anomalies and associations with sacral agenesis and scoliosis. This phenotype was associated with thoracolumbar/sacral spine surgery.

CONCLUSION

This is the first data-driven analysis designed to relate KFS patient phenotypes to surgical intervention and provides important insight that may inform targeted follow-up regimens and surgical decision-making.

LEVEL OF EVIDENCE

3.

Atlas assimilation: spectrum of associated radiographic abnormalities, clinical presentation, and management in children below 10 years

OBJECTIVE

To analyze the varied presentation and management of atlas assimilation with associated radiographic abnormalities in children in the MRI era METHODS: Database analysis of 313 children (less than 10 years) RESULTS: Atlas assimilation (AA) was associated with atlantoaxial dislocation in 12, abnormal skull base and Chiari I abnormality in 42, C2-C3 segmentation failure and instability and Chiari I abnormality in 74, and condylar hypoplasia and basilar invagination in 74. Proatlas segmentation failures were 54, atlantoaxial rotary dislocation in 26 with Goldenhar's syndrome, abnormal C1 atlas posterior arch causing dynamic compression of cord in 31 children. Vascular compromise was documented in 26 children. The study encompassed ages 6 months to 10 years. Cranial nerves commonly affected were glossopharyngeal, vagal, and hypoglossal nerves. Children below 2 years presented with torticollis, failure to thrive, difficulty swallowing, and motor and sensory deficits. Craniovertebral junction instability associated with AA was treated with custom-built craniocervical orthosis below 5 years. Closed reduction of instability or basilar invagination was attempted with neuromuscular blockade under anesthesia and traction above age 5 years. Successful reduction was treated with dorsal foramen magnum and atlas decompression with occiput-C2 dorsal fusion using rib grafts below the age of 5 years and instrumentation after that. Follow-up was 2 to 32 years. Neurological recovery was seen in nearly all patients.

CONCLUSIONS

Children with atlas assimilation and associated abnormalities may be symptomatic in early childhood. The treatment depends on the age and tailored to the abnormalities present. The long-term results have been successful.

Demographics, presentation and symptoms of patients with Klippel-Feil syndrome: analysis of a global patient-reported registry

INTRODUCTION

Klippel-Feil syndrome (KFS) occurs due to failure of vertebral segmentation during development. Minimal research has been done to understand the prevalence of associated symptoms. Here, we report one of the largest collections of KFS patient data.

METHODS

Data were obtained from the CoRDS registry. Participants with cervical fusions were categorized into Type I, II, or III based on the Samartzis criteria. Symptoms and comorbidities were assessed against type and location of fusion.

RESULTS

Seventy-five patients (60F/14M/1 unknown) were identified and classified as: Type I, n = 21(28%); Type II, n = 15(20%); Type III, n = 39(52%). Cervical fusion by level were: OC-C1, n = 17(22.7%), C1-C2, n = 24(32%); C2-C3, n = 42(56%); C3-C4, n = 30(40%); C4-C5, n = 42(56%); C5-C6, n = 32(42.7%); C6-C7, n = 25(33.3%); C7-T1, n = 13(17.3%). 94.6% of patients reported current symptoms and the average age when symptoms began and worsened were 17.5 (± 13.4) and 27.6 (± 15.3), respectively. Patients reported to have a high number of comorbidities including spinal, neurological and others, a high frequency of general symptoms (e.g., fatigue, dizziness) and chronic symptoms (limited range of neck motion [LROM], neck/spine muscles soreness). Sprengel deformity was reported in 26.7%. Most patients reported having received medication and invasive/non-invasive procedures. Multilevel fusions (Samartzis II/III) were significantly associated with dizziness (p = 0.040), the presence of LROM (p = 0.022), and Sprengel deformity (p = 0.036).

CONCLUSION

KFS is associated with a number of musculoskeletal and neurological symptoms. Fusions are more prevalent toward the center of the cervical region, and less common at the occipital/thoracic junction. Associated comorbidities including Sprengel deformity may be more common in KFS patients with multilevel cervical fusions. These slides can be retrieved under Electronic Supplementary Material.

Klippel-Feil: A constellation of diagnoses, a contemporary presentation, and recent national trends

Background:

Klippel–Feil syndrome (KFS) includes craniocervical anomalies, low posterior hairline, and brevicollis, with limited cervical range of motion; however, there remains no consensus on inheritance pattern. This study defines incidence, characterizes concurrent diagnoses, and examines trends in the presentation and management of KFS.

Methods:

This was a retrospective review of the Kid's Inpatient Database (KID) for KFSpatients aged 0–20 years from 2003 to 2012. Incidence was established using KID-supplied year and hospital-trend weights. Demographics and secondary diagnoses associated with KFS were evaluated. Comorbidities, anomalies, and procedure type trends from 2003 to 2012 were assessed for likelihood to increase among the years studied using ANOVA tests.

Results:

Eight hundred and fifty-eight KFS diagnoses (age: 9.49 years; 51.1% females) and 475 patients with congenital fusion (CF) (age: 8.33 years; 50.3% females) were analyzed. We identified an incidence rate of 1/21,587 discharges. Only 6.36% of KFS patients were diagnosed with Sprengel's deformity; 1.44% with congenital fusion. About 19.1% of KFS patients presented with another spinal abnormality and 34.0% presented with another neuromuscular anomaly. About 36.51% of KFS patients were diagnosed with a nonspinal or nonmusculoskeletal anomaly, with the most prevalent anomalies being of cardiac origin (12.95%). About 7.34% of KFS patients underwent anterior fusions, whereas 6.64% of KFS patients underwent posterior fusions. The average number of levels operated on was 4.99 with 8.28% receiving decompressions. Interbody devices were used in 2.45% of cases. The rate of fusions with <3 levels (7.46%) was comparable to that of 3 levels or greater (7.81%).

Conclusions:

KFS patients were more likely to have other spinal abnormalities (19.1%) and nonnervous system abnormalities (13.63%). Compared to congenital fusions, KFS patients were more likely to have congenital abnormalities such as Sprengel's deformity. KFS patients are increasingly being treated with spinal fusion.

Level of Evidence:

III

"Sandwich Deformity" in Klippel-Feil syndrome: A "Full-Spectrum" presentation of associated craniovertebral junction abnormalities

Klippel-Feil syndrome (KFS) is defined as congenital fusion of two or more cervical vertebrae resulting from a segmentation failure in the developing spine. According to Samartzis et al., the most commonly fused segments are found at C2/3 (74.1%) and C6/7 (70.4%). In patients with C2/3 fusion, especially when there is additional C1 occipitalization, several secondary anomalies including atlantoaxial dislocation (AAD), basilar invagination (BI), Chiari malformation, and syringomyelia can be identified. In this report, we present a case of a 12-year-old patient with C2/3 and occipitalization and a "Full-Spectrum" presentation of associated CVJ abnormalities including C0/1 fusion, AAD, BI, Chiari malformation, syringomyelia, myelopathy and cranial neuropathy received neurological decompression of the cervico-medullary junction by posterior reduction of the AAD and reconstruction of her CVJ using an unconventional hybrid construct due to a high-riding right vertebral artery in C2. To our knowledge, her "Full-Spectrum" presentation may include the most categories of concomitant abnormalities in the literature. In addition, She received neurological decompression of the cervico-medullary junction using an unconventional hybrid construct due to a high-riding vertebral artery in C2. Three months after the surgery, all of her symptoms recovered significantly. Neither Chiari malformation nor syringomyelia could be identified by MRI two years after the surgery. At the last follow-up (4 years), the patient became completely asymptomatic.

Pedicle Screw Combined With Lateral Mass Screw Fixation in the Treatment of Basilar Invagination and Congenital C2-C3 Fusion

STUDY DESIGN

Clinical evaluation of a surgical fixation technique featuring combined use of pedicle screw and lateral mass screw (LMS).

OBJECTIVE

Introduction of a novel technique for the treatment of congenital C2-C3 fusion and basilar invagination (BI).

SUMMARY OF BACKGROUND

Posterior occipitocervical fixation using C2 pedicle screw was widely used for BI. However, in cases where BI is concurrent with congenital C2-C3 fusion, the C2 pedicles tend to be thinner than that in normal population and hence more likely to fail. We prompted to tackle the issue by combining the pedicle screw with the additional use of LMS in attempt to strengthen the fixation.

METHODS

Twenty-five patients who underwent combined pedicle screw with LMS fixation were retrospectively studied. The instrument position, fusion status, and complications were analyzed.

RESULTS

None had spinal cord or vertebral artery injury. The average follow-up time was 20 months. Solid fusion was achieved in 23 patients (92%) as detected radiologically. Two cases suffered from recurred BI and instrument failure but eventually achieved solid fusion between the occiput and C2 was after revision. Among all 25 patients, 4 suffered from complications including instruments failure, cerebrospinal fluid leakage, and intracranial infection.

CONCLUSIONS

The clinical outcome indicates that the technique is reliable for the treatment of BI with congenital C2-C3 fusion.

Surgical Treatment of Occipitocervical Dislocation with Atlas Assimilation and Klippel-Feil Syndrome Using Occipitalized C1 Lateral Mass and C2 Fixation and Reduction Technique

OBJECTIVE

To introduce and assess a surgical treatment of occipitocervical (OC) dislocation with atlas assimilation and Klippel-Feil syndrome (KFS) using occipitalized C1 lateral mass and C2 fixation and reduction technique.

METHODS

From January 2007 to August 2013, 58 symptomatic patients with OC dislocation and KFS of C2-3 congenital fusion and atlas assimilation were surgically treated in our institution via this technique. After opening the C1-2 facet joints via a posterior approach, OC reduction was conducted by intraoperative manipulation and C1 lateral mass and C2 pedicle screw and rod fixation. The instrument position, fusion status, and clinical outcome were analyzed.

RESULTS

The average follow-up was 36 months (range, 18-52 months). Radiologically, effective reduction was achieved in 56 patients (96.6%) and <50% reduction in 2 (3.4%) who had additional transoral decompression. Neurologic improvement and solid bone fusion were achieved in all patients. The clinical symptoms improved for all patients, with the averaged Japanese Orthopedic Association myelopathy scores increasing from 11.5 to 15.6 (P < 0.01).

CONCLUSIONS

In patients with OC dislocation and KFS of C2-3 fusion and atlas assimilation, posterior manipulative reduction combined with occipitalized C1 lateral mass and C2 fixation provides a reliable and effective treatment.

"Clinical triad" findings in pediatric Klippel-Feil patients

BACKGROUND

It has been propagated that patients with Klippel-Feil syndrome (KFS) exhibit "clinical triad" findings (CTFs), known as a short neck, low posterior hairline, and limited cervical range of motion (ROM). However, the literature has noted that up to 50 % of KFS cases may not present with such findings and the reasoning behind such assertions remains speculative. As such, the following study addressed the association between CTFs to that of congenitally-fused cervical segments and other risk factors in KFS patients.

METHODS

We conducted a retrospective clinical study based on prospectively collected radiographic data. Thirty-one KFS patients at a single institution were assessed. Radiographs were used to evaluate the location and extent of congenitally-fused segments (spanning the occiput (O) to the first thoracic vertebra (T1)), as well as examining coronal and sagittal cervical alignments based on the Samartzis et al. KFS classification. Clinical records were evaluated to account for the initial clinical assessment of CTFs. Patients were further stratified into two groups: Group 1 included patients noted to have any CTFs, while Group 2 included patients who had no such findings.

RESULTS

There were 12 males and 19 females (mean age at initial consultation: 9.7 years). No evidence of any of the CTFs was shown in 35.5 % of patients, whereas 38.7, 16.2 and 9.7 % were determined to have one, two or all three criteria, respectively. Limited cervical ROM was the most common finding (64.5 % of patients). In Group 1, 25 % had a short neck, 30 % a low posterior hairline, and 100 % exhibited limited cervical ROM. Group 1 had a mean of 3.9 fused cervical segments, whereas Group 2 had a mean of 2.5 fused cervical segments (p = 0.028). Age, sex-type, occipitalization and alignment parameters did not significantly differ to Group-type (p > 0.05). In Group 1, based on the Samartzis et al. Types I, II, and III, 16.7, 73.3, and 80.0 % of the patients, respectively, had at least one CTF.

CONCLUSIONS

Complete CTFs were not highly associated during the clinical assessment of young KFS patients. However, KFS patients with extensive, congenitally-fused segments (i.e. Samartzis et al. Type III) were significantly more likely to exhibit one of the components of the CTF, which was predominantly a limited cervical ROM. Clinicians managing young pediatric patients should not rely on the full spectrum of CTFs and should maintain a high-index of suspicion for KFS, in particular in individuals that exhibit associated spinal findings, such as congenital scoliosis.

Effects of cervical deep muscle strengthening in a neck pain: a patient with klippel-feil syndrome

[Purpose] This study aimed to identify the effects of cervical deep muscle strengthening (CDS) on neck pain in a patient with Klippel-Feil syndrome (KFS). [Subjects and Methods] The subjects was a 39 year-old woman with neck pain and KFS that included incomplete block vertebrae in the C2–3 segments and block vertebrae in the C6–7 segments. The subject performed an exercise program including cervical strengthening exercise (level 1) and CDS exercise (level 2) for 6 weeks. Neck pain intensity was measured using the visual analogue scale (VAS) and the pressure pain threshold (PPT). All measurements were obtained before and after the CDS exercise program. [Results] The VAS and PPT measurements decreased; range of motion in the cervical joint increased. [Conclusion] CDS exercises were effective interventions for reducing neck pain in a patient with Klippel-Feil syndrome.

Morphological and clinical feasibility of C3 pedicle screw instrumentation in patients with congenital C2-3 fusion

PURPOSE

Congenital C2-3 fusion (C2-3CF) is often involved in patients with atlantoaxial dislocation, and posterior occipitocervical fixation surgery is usually required. Hypoplasia of C2 pedicle is common in such patients, making C2 pedicle screws (PS) instrumentation inapplicable. Because of congenital fusion, C3PS instrumentation would be an ideal alternative for it will not sacrifice an additional motion segment; however, the morphological and clinical feasibility has not been previously reported.

METHODS

We included 42 C2-3CF patients to this study and evaluated pedicle trajectories of C2 and C3 using a three-dimensional CT. Clinical applications of C3PS instrumentation were evaluated and followed.

RESULTS

Among the 42 patients, 23 (54.8%) and 8 (19.0%) had C2 and C3 pedicle trajectory diameters <4.0 mm, respectively. The bisection line of the fused C2-3 lamina was used to represent the superior border of C3 articular mass; the entry point of C3 pedicle was located at 3 mm inferior to the assumed superior border and 3.2 mm medial to the lateral border. Bilateral C3PS instrumentations were successfully adopted in 22 patients. No spinal cord or vertebral artery injury occurred; postoperative CT showed a trajectory breach rate of 17.4% for C3PS. After mean of 3.6-year follow-up, no implant failure was documented.

CONCLUSIONS

C3PS instrumentation is morphologically and clinically feasible for a large proportion of patients with C2-3CF and can serve as another reliable alternative for C2PS instrumentation. Preoperative evaluation of pedicle trajectory of C2-3CF with three-dimensional CT is highly valuable in the choice of proper fixation methods.

Occipital-C2 transarticular fixation for occipitocervical instability associated with occipitalization of the atlas in patients with klippel-feil syndrome, using intraoperative 3-dimensional navigation system

STUDY DESIGN

Retrospective case series.

OBJECTIVE

The aim of this study was to describe the clinical outcomes of cervical reduction and occipital-C2 transarticular (OCTA) fixation with an assistance of intraoperative 3-dimensional navigation system (ITNS) during the treatment of reducible occipitocervical instability (OCI) in patients with Klippel-Feil syndrome (KFS) with occipitalization of the atlas and fusion of C2-C3.

SUMMARY OF BACKGROUND DATA

Patients with KFS have congenital fusions of at least 2 cervical segments and may gradually develop symptoms at the hypermobile articulations adjacent to the cervical synostosis. This is particularly common in patients with KFS with occipitalization of the atlas and C2-C3 fusion. These patients may be at risk for instability and neurological complications of the occipitocervical junction that require occipitocervical reconstruction and fusion. Numerous treatment techniques are available for this pathological condition. However, there has yet to be a study of reducible OCI, showing successful treatment with intraoperative reduction and posterior OCTA fixation using ITNS.

METHODS

From 2006 to 2011, 9 patients with KFS with reducible OCI attributed to occipitalization of the atlas and C2-C3 fusion were surgically treated. After a limited foramen magnum decompression, reduction of the OCI was conducted by intraoperative cervical traction and extension, followed by OCTA fixation using a direct posterior approach and with the assistance of ITNS. The follow-up period ranged from 6 to 60 months (mean, 31 mo).

RESULTS

Good decompression and bone fusion were achieved in all the patients. The clinical symptoms had improved for all patients. There were no intraoperative or postoperative complications.

CONCLUSION

In patients with KFS with occipitalization of the atlas and C2-C3 fusion, manual cervical traction in tandem with cervical extension, followed by posterior OCTA fixation and fusion provides a safe, effective treatment of OCI and ventral brainstem impingement. IFTN is a feasible tool for monitoring cervical reduction and OCTA screw insertion in patients with KFS with this pathological condition.

Congenital variations of the upper cervical spine and their importance in preoperative diagnosis. A case report and a review of the literature

Several variations of the bony and vascular anatomy around the first and second cervical vertebrae have been reported. Failure to recognise these variations can complicate operations on the upper cervical spine. We present a patient with recent onset of cervical myelopathy due to stenosis at the C3-4 level. Preoperative evaluation identified Klippel-Feil syndrome with cervical fusion of C2-3, aplasia of posterior arch of C1, anomalous vertebral artery course and a "ponticulus posticus" of C2. The combination of these variations in a Klippel-Feil syndrome patient has never been reported. Thus, we recommend a thorough preoperative imaging evaluation, with CT scan and CT angiography or DSA, in addition to plain radiographs. This evaluation is imperative, before a cervical spine surgery, allowing a better understanding of the anatomy, in order to minimise the risks of misplacement of cervical instrumentation especially in such patients.

Cervical vertebral column morphology in patients with obstructive sleep apnoea assessed using lateral cephalograms and cone beam CT. A comparative study

OBJECTIVES

Few studies have described morphological deviations in obstructive sleep apnoea (OSA) patients on two-dimensional (2D) lateral cephalograms, and the reliability of 2D radiographs has been discussed. The objective is to describe the morphology of the cervical vertebral column on cone beam CT (CBCT) in adult patients with OSA and to compare 2D lateral cephalograms with three-dimensional (3D) CBCT images.

METHODS

For all 57 OSA patients, the cervical vertebral column morphology was evaluated on lateral cephalograms and CBCT images and compared according to fusion anomalies and posterior arch deficiency.

RESULTS

The CBCT assessment showed that 21.1% had fusion anomalies of the cervical column, i.e. fusion between two cervical vertebrae (10.5%), block fusions (8.8%) or occipitalization (1.8%). Posterior arch deficiency occurred in 14% as partial cleft of C1 and in 3.5% in combination with block fusions. The agreement between the occurrence of morphological deviations in the cervical vertebral column between lateral cephalograms and CBCT images showed good agreement (κ = 0.64).

CONCLUSIONS

Prevalence and pattern in the cervical column morphology have now been confirmed on CBCT. The occurrence of morphological deviations in the cervical vertebral column showed good agreement between lateral cephalograms and CBCT images. This indicates that 2D lateral cephalograms (already available after indication in connection with, e.g. treatment planning) are sufficient for identifying morphological deviations in the cervical vertebral column. For a more accurate diagnosis and location of the deviations, CBCT is required. New 3D methods will suggest a need for new detailed characterization and division of deviations in cervical vertebral column morphology.

Cable-Strengthened C2 Pedicle Screw Fixation in the Treatment of Congenital C2-3 Fusion, Atlas Occipitalization, and Atlantoaxial Dislocation

BACKGROUND:

Atlas occipitalization and congenital C2-3 fusion often result in atlantoaxial dislocation (AAD) and superior odontoid migration that requires occipitocervical fixation. The widely used technique is posterior occiput-C2 fixation with pedicle screws. However, congenital C2-3 fusion cases tend to have thinner C2 pedicles that are inadequate for normal-sized pedicle screw fixation. With the presence of AAD, the strength of the fixation is further compromised as the C2 pedicle screws (C2PS) sustain considerable cephalic shearing force during the reduction procedure. Therefore, a novel technique has been developed to augment the C2 pedicle screw fixation with a strengthening cable.

OBJECTIVE:

To introduce and assess this new technique.

METHODS:

Seventy-six patients who underwent this procedure were reviewed. The position of the instrument and resultant fusion were examined retrospectively. In the biomechanical test, 6 fresh specimens were subjected to 2 types of fixation in the order of Oc-C2 screw-plate fixation followed by additional use of strengthening cable. Under 3 loading modes (extension-flexion, lateral bending, and axial rotation), the relative movement between the occiput and C2 was measured and compared in the form of range of motion.

RESULTS:

The average follow-up time was 26 months. Solid fusion was achieved in 75 patients (98.7%) as assessed radiologically. The only patient who experienced hardware failure eventually obtained solid fusion between the occiput and C2 after revision. Biomechanically, there was significant difference between the occiput and C2 fixation and cable-strengthened fixation in range of motion for all modes.

CONCLUSION:

This technique is a promising option for the treatment of AAD with congenital C2-3 fusion and occipitalization. Biomechanically, this technique can reduce the occipital-axial motion significantly compared with occiput-C2 fixation.

Cervical scoliosis in the Klippel-Feil patient

STUDY DESIGN

Retrospective study.

OBJECTIVE

This study addressed in patients with Klippel-Feil syndrome (KFS), the role of congenitally fused cervical patterns, risk factors, and cervical symptoms associated with cervical scoliosis.

SUMMARY OF BACKGROUND DATA

KFS is an uncommon condition, characterized as improper segmentation of one or more cervical spine segments with or without associated spinal or extraspinal manifestations. "Scoliosis" is potentially the most common manifestation associated with KFS. However, the role of congenitally fused cervical patterns along with additional potential risk factors and their association with cervical scoliosis, and its relationship with cervical spine-related symptoms remain largely unknown.

METHODS

Plain radiographs were utilized to assess the location of congenitally fused cervical segments (O-T1), degree of coronal cervical alignment, and any additional cervical and thoracic spine abnormalities. The classification scheme, as proposed by Samartzis et al of congenitally fused cervical patterns (Types I-III) in KFS patients, was utilized and additional fusion and region-specific patterns were assessed. Patients with coronal cervical alignments of 10° or greater were regarded scoliotic. Patient demographics and the presence of cervical spine-related symptoms were also assessed.

RESULTS

Thirty KFS patients were assessed (mean age, 13.5 yr). The mean coronal cervical alignment was 18.7° and scoliosis was noted in 16 patients. Patients that exhibited congenital fusion of the mid and lower cervical spine region, had multiple, contiguous congenitally fused segments (Type III), and associated vertebral malformations (e.g., hemivertebrae) were highly associated with the presence of cervical scoliosis (P < 0.05). Ten patients exhibited cervical spine-related symptoms; however, no statistically significant difference was noted between the presence of symptoms and coronal cervical alignment (P = 0.815) and cervical scoliosis (P = 0.450).

CONCLUSION

The study noted a prevalence of cervical scoliosis to occur in 53.3% of young KFS patients. Such patients that exhibited congenital fusion of the mid and lower cervical spine region, had multiple, contiguous congenitally fused segments (Type III), and associated vertebral malformations (e.g., hemivertebrae) were highly associated with the presence of cervical scoliosis. However, in young KFS patients, the presence of cervical scoliosis may not be associated with the manifestation of cervical spine-related symptoms.

Associations between the Cervical Vertebral Column and Craniofacial Morphology

Aim. To summarize recent studies on morphological deviations of the cervical vertebral column and associations with craniofacial morphology and head posture in nonsyndromic patients and in patients with obstructive sleep apnoea (OSA). Design. In these recent studies, visual assessment of the cervical vertebral column and cephalometric analysis of the craniofacial skeleton were performed on profile radiographs of subjects with neutral occlusion, patients with severe skeletal malocclusions and patients with OSA. Material from human triploid foetuses and mouse embryos was analysed histologically. Results. Recent studies have documented associations between fusion of the cervical vertebral column and craniofacial morphology, including head posture in patients with severe skeletal malocclusions. Histological studies on prenatal material supported these findings. Conclusion. It is suggested that fusion of the cervical vertebral column is associated with development and function of the craniofacial morphology. This finding is expected to have importance for diagnostics and elucidation of aetiology and thereby for optimal treatment.

Pedicle versus laminar screws: what provides more suitable C2 fixation in congenital C2-3 fusion patients?

Patients with Klippel-Feil syndrome (KFS) have congenital fusions of at least 1 cervical motion segment, and often present with compensatory hypermobility or symptomatic stenosis of the cranio-vertebral junction which requires occipitocervical reconstruction and fusion. One subgroup of KFS patients in which this is particularly common is those with isolated C2-3 congenital fusion (C2-3 CF). The anatomic suitability for C2 pedicle and laminar screw placement had been analyzed in the general adult population, and guidelines for their techniques had been established. However, the feasibility and safety of the two techniques in KFS patients with congenital C2-3 fusion has not been reported. This radiographic study was performed to evaluate the feasibility of these two widely used methods in such patients. We recruited 108 patients with atlantoaxial dislocation and reconstructed CTs were performed. Among them, 53 had C2-C3 congenital fusion diagnosed as KFS and 55 had normal cervical segmentation (NCS). The maximum possible diameters and length were measured along the ideal screw trajectories. Both of mean diameters and lengths of the C2 laminar screw trajectory in the C2-3 CF group were significantly larger than that in NCS. Mean diameters of the C2 pedicle screw trajectory in this group were significantly smaller than that in NCS group, however, C2-3 CF patients had longer pedicle paths than NCS. In the C2-3 CF group, all 53 cases had suitable trajectory for C2 laminar screw, while 21 (39.6%) had a pedicle diameter less than 4.5 mm. In the NCS group, 5 cases (9.1%) had a pedicle diameter less than 4.5 mm. All 108 cases had sufficient diameters for C2 laminar screw placement. Klippel-Feil patients with C2-3 CF are good candidates for the technique of C2 laminar screw. Preoperative radiography should be carefully evaluated and the option of C2 fixation be determined with a thorough consideration in these patients.

Atlantoaxial rotatory fixation in the setting of associated congenital malformations: a modified classification system

STUDY DESIGN

A case report.

OBJECTIVE

To raise awareness of the development of atlantoaxial rotatory fixation (AARF) in the setting of congenital vertebral anomalies/malformations.

SUMMARY OF BACKGROUND DATA

Klippel-Feil Syndrome (KFS) is a complex, heterogeneous condition noted as congenital fusion of 2 or more cervical vertebrae with or without spinal or extraspinal manifestations. Although believed to be a rare occurrence in the population, KFS may be underreported. Proper diagnosis of KFS and other congenital conditions affecting the spine is imperative to devise proper management protocols and avoid potential complications resulting from the altered biomechanics associated with such conditions and their abnormal vertebral morphology. Craniovertebral dislocation and AARF may cause severe cervicomedullary and spinal cord compression and could thereby be potentially fatal, especially in patients with KFS who present with congenitally-associated comorbidities.

METHODS

A 13-year-old boy with Chiari type I malformation, craniofacial abnormalities, and other irregularities underwent thoracolumbar spine surgery for his scoliosis curve correction at another institution, which immediately following surgery he became a quadriparetic. The initial preoperative assessment of his cervical spine was limited and the associated KFS was initially undiagnosed. At 14 years of age, he presented to our clinic with an ASIA-C spinal cord injury. Plain radiographs, normal and 3-dimensional reformatted computed tomographs (CT), and magnetic resonance imaging (MRI) noted assimilation of the patient's occiput to the atlas (occipitalization) with congenital fusion of C2-C3, indicative of KFS, and the presence of anterior craniovertebral dislocation with a Fielding and Hawkins type II AARF. Closed reduction of the craniovertebral dislocation was noted, but his atlantoaxial rotatory subluxation was nonresponsive and fixed (AARF). As such, at the age of 14, the patient underwent posterior instrumentation and fusion from the occiput to C4 to maintain reduction of thecraniovertebral dislocation and reduce his AARF.

RESULTS

At 9 months postoperative follow-up of his craniovertebral surgery, the instrumentation remained intact, reduction of the atlantoaxial rotatory subluxation was maintained, and posterior bone fusion was noted. Neurologically, he remained an ASIA-C without any substantial return of function.

CONCLUSION

This report raises awareness for the need of a thorough evaluation of the cervical spine to determine patients at high risk for craniovertebral dislocation and atlantoaxial rotatory subluxation, primarily in the context of KFS or other congenital conditions. Three-dimensional CT and MR imaging are ideal radiographic methods to determine the presence and extent of craniovertebral dislocation, AARF, and of abnormal vertebral anatomy/malformations. In addition, the authors propose a modification to the Fielding and Hawkins classification of AARF to include variants and subtypes that account for abnormal anatomy and congenital anomalies/malformations.

Atlantoaxial Subluxation in Two Dogs With Cervical Block Vertebrae

Atlantoaxial (AA) subluxation is an uncommon disorder that can cause various degrees of neurological deficits in dogs. Block vertebra is a congenital deformation involving the fusion of two or more vertebrae. This report describes two dogs with cervical block vertebrae from C2 to C5 and C2 to C4, respectively. We hypothesize that the fused cervical vertebrae created a “fulcrum effect” at the AA joint and predisposed these dogs to traumatic AA subluxation.

Radiographic analysis of the cervical spine in patients with retro-odontoid pseudotumors

STUDY DESIGN

A retrospective review of 10 consecutive patients with a noninflammatory retro-odontoid pseudotumor.

OBJECTIVE

To examine the radiographic characteristics in patients with a retro-odontoid pseudotumor and to evaluate the efficacy of posterior fusion.

SUMMARY OF BACKGROUND DATA

A retro-odontoid pseudotumor, a reactive fibrocartilaginous mass, is known to develop after chronic atlantoaxial instability; however, one-third of the reported cases showed no overt atlantoaxial instability. The pathomechanism for such "atypical" cases remains unclear, although altered cervical motion secondary to ossification of the anterior longitudinal ligament (OALL) or severe spondylosis has been implicated.

METHODS

We reviewed the charts and radiographs of 10 patients with a retro-odontoid pseudotumor who underwent surgery. Preoperative radiographs were evaluated for atlas-dens interval (ADI), presence of OALL, range of motion, and segmental motion adjacent to the atlantoaxial joint. Computed tomography was evaluated for degenerative changes of zygapophysial joints.

RESULTS

There were 6 men and 4 women. Atlantoaxial instability (ADI >4 mm) was observed in 2 patients. ADI was less than 3 mm in 5 patients. Frequent association of OALL (6 patients) and marked decrease in C2 to C7 range of motion (mean, 17.6 degrees ; range, 3 degrees-36 degrees ) were noted. Ankylosis of O-C1 was observed in 4 patients and C2 to C3 in 6. Severe degenerative change of C2 to C3 zygapophysial joint was observed in 4 patients. The patients underwent occipito-cervical fusion (9 patients) or direct removal of the pseudotumor (1 patient). Postoperative magnetic resonance imaging invariably demonstrated the mass regression.

CONCLUSION

Retro-odontoid pseudotumors were not always associated with radiographic atlantoaxial instability. Our data indicate that extensive OALL and ankylosis of the adjacent segments are risk factors for the formation of the pseudotumor. Retro-odontoid pseudotumors may develop as an "adjacent segment disease" after altered biomechanics of the cervical spine, especially those in the adjacent segments. Posterior fusion was effective even in cases without radiographic atlantoaxial instability.

Craniocervical developmental anatomy and its implications

INTRODUCTION

Congenital and developmental osseous abnormalities and anomalies that affect the craniocervical junction complex can result in neural compression and vascular compromise and can manifest itself with abnormal cerebrospinal fluid dynamics. An understanding of the development of the craniocervical junction is essential to recognize the pathological abnormalities.

MATERIALS AND METHODS

Atlas assimilation, segmentation failures, os odontoideum, basilar invagination, and the various syndromes that affect the craniocervical junction have been analyzed. The natural history provides an added insight into its treatment.

RESULTS

Proatlas segmentation abnormalities surrounded the foramen magnum and the posterior arch of C1. Hindbrain herniation was associated in 33 of the 90 children involved. Spastic quadriparesis presented in 80% and lower cranial nerve abnormalities in 33%. Vertebrobasilar dysfunction was observed in 40% and trauma presentation seen in 60% of individuals. Atlas assimilation was present in 550 individuals who were evaluated for craniovertebral junction abnormalities. Hindbrain herniation occurred in 38%. Segmentation failure of C2 and C3 vertebrae compounded the abnormal dynamics resulting in atlantoaxial instability. This was a reducible instability with formation of pannus around the odontoid process until it became irreducible at approximately 14 years of age. Unilateral atlas assimilation caused torticollis in children. Os odontoideum was investigated regarding craniocervical trauma at a young age.

CONCLUSION

The conclusion was that os odontoideum was associated with an unrecognized fracture in children below the age of 5 with a previously normal odontoid structure as observed in our series. Atlas and axis abnormalities were reviewed in this series. This large database has provided an understanding of the natural history of many entities and allowed treatment protocols to be established that have stood the test of time.

The extent of fusion within the congenital Klippel-Feil segment

STUDY DESIGN

Retrospective radiographic review.

OBJECTIVE

To evaluate in patients with Klippel-Feil syndrome (KFS) the presence and extent of specific fusion patterns across involved cervical segments and their association with age-specific parameters.

SUMMARY OF BACKGROUND DATA

While the radiographic hallmark of KFS is characterized by congenital fusion of at least one cervical motion segment, the relation between age and the extent of segmental congenital fusion remains speculative.

METHODS

A radiographic review of 31 patients with KFS at a single institution. Plain radiographs were used to assess fusion across the vertebral segment as entailing the anterior elements, posterior elements, or complete segment from O-T1. Age-specific stratifications were also performed.

RESULTS

A mean of 3.7 fused segments and a sum of 116 fused segments were noted. From C2-T1, complete fusion of the involved segment represented 77.8% at 10 years or older, 87.5% at 15 years or older, 91.7% at 16 years or older, 95.7% at 17 years or older, 86.5% who were skeletally mature, and 100% at adulthood. Similar trends were not noted for segments of O-C2. In absence of complete segmental fusion, the posterior elements exhibited a higher incidence of fusion than the anterior elements. Statistically significant differences between anterior/posterior to complete segmental fusion with respect to different age markers entailed segments of C2-C3, C4-C5, and C6-C7 (P < 0.05).

CONCLUSION

This study provides some insight into the potential developmental aspects of the extent of segmental fusion of the cervical spine in patients with KFS. In older patients, complete fusion of involved fused segments was more prevalent in regards to C2-T1; however, such an observation was not noted for segments from O-C2. In the absence of complete segmental fusion, fusion of the posterior elements was more often noted than fusion of the anterior elements. Awareness of the varied phenotypic expression of segmental fusion patterns of the cervical spine in patients with KFS underlines theimportance of thorough evaluation of the cervical spine to assess the presence and extent of segmental fusion to facilitate in the identification of neurologic risk factors.

2008 Young Investigator Award: The role of congenitally fused cervical segments upon the space available for the cord and associated symptoms in Klippel-Feil patients

STUDY DESIGN

A prospective radiographic and retrospective clinical chart review.

OBJECTIVE

This study evaluated the role of congenitally fused cervical segments in relation to the space available for the cord (SAC) and associated cervical spine-related symptoms (CSS) in patients with Klippel-Feil Syndrome (KFS).

SUMMARY OF BACKGROUND DATA

KFS is a developmental disorder presenting with congenital fusion of at least 2 cervical vertebrae. The effects of congenitally fused cervical segments in relation to the SAC and associated symptoms in KFS patients remain speculative and have not been thoroughly addressed in the literature.

METHODS

At a single institution, a prospective radiographic and clinical evaluation of 29 KFS patients was conducted. Based on plain radiographs, assessment of the SAC consisted of the posterior atlantodens interval, the midvertebral body SAC (C2-C7), and the interbody SAC (C2-C3-C7-T1). Vertebral body width (VBW) from C2 to C7 and the presence of occipitalization (O-C1) were also noted. Torg ratios were obtained at each level. Demographics, medical history, and the presence of CSS were noted based on clinical chart review.

RESULTS

Ten males and 19 females were reviewed (mean age, 13.4 years). A significant correlation was noted between the overall VBWs to the number of fused segments, age, and skeletal maturity (P < 0.05), but not to sex-type, O-C1, and SAC levels (P > 0.05). In the presence of a fused segment, individualized SAC levels tended to have greater canal dimensions and cephalad/caudal VBWs were less. Cephalad and caudal Torg ratios in relation to a segment were greater in all fused segments, and with 4 or greater fused segments (P < 0.05). Number of levels fused, sex-type, skeletal maturity, and O-C1 were not significantly associated with the presence of symptoms (P > 0.05). Symptomatic patients had smaller VBWs than nonsymptomatic patients (P = 0.027) and an overall decrease in SAC at the interbody disc level, primarily at C6-C7 (P > 0.05). Smaller Torg ratios were noted in symptomatic patients, specifically myelopathic patients.

CONCLUSION

Congenital fusion in KFS may arrest the normal vertebral development, which may affect appositional bone growth. Such effects on the VBW could potentially contribute to an increase in the SAC. Such a development may delay neurologic compromise stemming from the congenital fusion process and subsequent degenerative manifestations.

Sprengel's deformity in Klippel-Feil syndrome

STUDY DESIGN

A retrospective study.

OBJECTIVES

To address the role of congenitally fused cervical segments, the degree of cervical scoliosis, and other risk factors on the presence of Sprengel's deformity (SD) in young patients with Klippel-Feil syndrome (KFS).

SUMMARY OF BACKGROUND DATA

Numerous abnormalities are associated with KFS, one of the most common being SD. It has been postulated that more severe forms of KFS may be more associated with extraspinal manifestations, such as SD.

METHODS

Thirty KFS patients from a single institution were reviewed. Cervical neutral lateral/dynamic/anteroposterior and thoracic anteroposterior plain radiographs were assessed. Radiographically, occipitalization (O-C1), number of congenitally fused segments (C1-T1), classification type (Types I-III), degree of cervical scoliosis, and the presence of SD was assessed. Clinical chart review entailed patient demographics and evidence of the clinical assessment of SD. The threshold for statistical significance was P < 0.05.

RESULTS

There were 11 males (36.7%) and 19 females (63.3%) with a mean age of 13.5 years (range, 2.7-26.3 years). Occipitalization was present in 10 (33.3%) individuals and C2-C3 was the most common level fused (70.0%). The mean number of congenitally fused segments was 3.3 (range, 1-6 levels). The mean degree of cervical scoliosis was 17.3 degrees (range, 0 degrees-67 degrees). There were 6 (20%) Type I, 15 Type II (50.0%), and 9 Type III (30%) patients. SD was noted in 5 (16.7%) of the patients. Four patients had unilateral, whereas 1 patient had bilateral SD. There was 4.0 and 3.1 mean number of congenitally fused segments in patients with or without SD, respectively. SD did not occur in Type I patients (single fused block). The presence of SD was found to be nonsignificant regarding sex type (P = 0.327), presence of occipitalization (P = 0.300), number of congenitally fused segments (P = 0.246), specific congenitally fused segments (P > 0.05), classification type (P > 0.05), and scoliosis (P = 0.702).

CONCLUSION

SD occurred in 16.7% of KFS patients. Sex type, number of congenitally fused segments, specific fused patterns, occipitalization, classification type, and the degree of cervical scoliosis did not seem to be significantly associated with the presence of SD in KFS patients in our series. Thorough examination for the presence and degree of SD in KFS is necessary, irrespective of the extent of cervical abnormalities. Alternatively, the treating physician should not dismiss a thorough cervical spine examination in patients with SD, evaluating factors that may predispose the KFS patient to an increased risk of neurologic injury.

Superior odontoid migration in the Klippel-Feil patient

Klippel-Feil syndrome (KFS) is an uncommon condition noted primarily as congenital fusion of two or more cervical vertebrae. Superior odontoid migration (SOM) has been noted in various skeletal deformities and entails an upward/vertical migration of the odontoid process into the foramen magnum with depression of the cranium. Excessive SOM could potentially threaten neurologic integrity. Risk factors associated with the amount of SOM in the KFS patient are based on conjecture and have not been addressed in the literature. Therefore, this study evaluated the presence and extent of SOM and the various risk factors and clinical manifestations associated therein in patients with KFS. Twenty-seven KFS patients with no prior history of surgical intervention of the cervical spine were included for a prospective radiographic and retrospective clinical review. Radiographically, McGregor's line was utilized to evaluate the degree of SOM. Anterior and posterior atlantodens intervals (AADI/PADI), number of fused segments (C1-T1), presence of occipitalization, classification-type, and lateral and coronal cervical alignments were also evaluated. Clinically, patient demographics and presence of cervical symptoms were assessed. Radiographic and clinical evaluations were conducted by two independent blinded observers. There were 8 males and 19 females with a mean age of 13.5 years at the time of radiographic and clinical assessment. An overall mean SOM of 5.0 mm (range = -1.0 to 19.0 mm) was noted. C2-C3 (74.1%) was the most commonly fused segment. A statistically significant difference was not found between the amount of SOM to age, sex-type, classification-type, AADI, PADI, and lateral cervical alignment (P > 0.05). A statistically significant greater amount of SOM was found as the number of fused segments increased (r = 0.589; P = 0.001) and if such levels included occipitalization (r = 0.616; P = 0.001). A statistically significant greater amount of SOM was also found with an increase in coronal cervical alignment (r = 0.413; P = 0.036). Linear regression modeling further supported these findings as the strongest predictive variables contributing to an increase in SOM. A 7.20 crude relative risk (RR) ratio [95% confidence interval (CI) = 1.05-49.18; risk differences (RD) = 0.52] was noted in contributing to a SOM greater than 4.5 mm if four or more segments were fused. Adjusting for coronal cervical alignment greater than 10 degrees , five or more fused segments were found to significantly increase the RR of a SOM greater than 4.5 mm (RR = 4.54; 95% CI = 1.07-19.50; RD = 0.48). The RR of a SOM greater than 4.5 mm was more pronounced in females (RR = 1.68; 95% CI = 0.45-6.25; RD = 0.17) than in males. Eight patients (29.6%) were symptomatic, of which symptoms in two of these patients stemmed from a traumatic event. However, a statistically significant difference was not found between the presence of symptoms to the amount of SOM and other exploratory variables (P > 0.05). A mean SOM of 5.0 mm was found in our series of KFS patients. In such patients, increases in the number of congenitally fused segments and in the degree of coronal cervical alignment were strongly associated risk factors contributing to an increase in SOM. Patients with four or greater congenitally fused segments had an approximately sevenfold increase in the RR in developing SOM greater than 4.5 mm. A higher RR of SOM more than 4.5 mm may be associated with sex-type. However, 4.5 mm or greater SOM is not synonymous with symptoms in this series. Furthermore, the presence of symptoms was not statistically correlated with the amount of SOM. The treating physician should be cognizant of such potential risk factors, which could also help to indicate the need for further advanced imaging studies in such patients. This study suggests that as motion segments diminish and coronal cervical alignment is altered, the odontoid orientation is located more superiorly, which may increase the risk of neurologic sequelae.

Classification of congenitally fused cervical patterns in Klippel-Feil patients: epidemiology and role in the development of cervical spine-related symptoms

STUDY DESIGN

A retrospective cohort and series review.

OBJECTIVES

To determine the role of cervical spine fusion patterns on the development of cervical spine-related symptoms (CSS) in patients with Klippel-Feil syndrome (KFS) and evaluate age- and time-dependent factors that may contribute to fused cervical patterns and the development of the CSS.

SUMMARY OF BACKGROUND DATA

Although the "hallmark" of KFS is the presence of congenitally fused cervical vertebrae, the epidemiology and role of specific cervical fused patterns are limited. In addition, the incidence of symptoms and various age- and time-dependent factors that are directly attributed to the congenitally fused cervical segments in KFS patients is unknown.

METHODS

A radiographic and clinical review of 28 KFS patients at a single institution. Radiographically, Type I patients were defined as having a single congenitally fused cervical segment. Type II patients demonstrated multiple noncontiguous, congenitally fused segments, and Type III patients had multiple contiguous, congenitally fused cervical segments. Clinical records were reviewed for patient demographics, presence and type of symptoms, and clinical course.

RESULTS

Twelve males and 16 females were reviewed for clinical follow-up (mean, 8.5 years) and radiographic assessment (mean, 8.0 years). The mean age at presentation was 7.1 years; mean age of onset of CSS was 11.9 years. Clinically, 64% had no complaints referable to their cervical spine. Radiographically, 25%, 50%, and 25% were Type I, Type II, and Type III, respectively. At final clinical follow-up, 2 patients were myelopathic (Type II and Type III) and 2 were radiculopathic (Type II and Type III). Type III patients were largely asymptomatic but were associated with the highest risk in developing radiculopathy or myelopathy than Type I or Type II patients. Axial symptoms were predominantly associated with Type I patients. Myelopathic patients developed initial CSS earlier (meanage, 10.6 years) than patients with predominant axial (mean age, 13.0 years) or radiculopathic symptoms (mean age, 18.6 years) (P > 0.05). Patients with radiculopathy or myelopathy were diagnosed at a mean age of 17.9 years. Type I patients were predominantly females, while males were largely Type III. Surgery entailed 11% of patients, composed of 2 myelopathic patients (Type II and Type III) and 1 radiculopathic patient (Type II).

CONCLUSIONS

In our review, 36% of KFS patients had CSS and the majority had axial symptoms. Axial neck symptoms were highly associated with Type I patients, whereas predominant radicular and myelopathic symptoms occurred in Type II and Type III patients. This classification system has promise for early detection for CSS. Activity modification should be stressed in KFS patients at high risk for neurologic compromise.

Symptomatic cervical disc herniation in a pediatric Klippel-Feil patient: the risk of neural injury associated with extensive congenitally fused vertebrae and a hypermobile segment

STUDY DESIGN

A case report.

OBJECTIVE

To report the occurrence of a herniated cervical disc following a high-impact activity in a pediatric Klippel-Feil patient who presented with spinal cord compression, myelopathy, and myelomalacia requiring posterior instrumented fusion followed by an anterior discectomy and fusion at the hypermobile nonfused segment.

SUMMARY OF BACKGROUND DATA

The primary hallmark of Klippel-Feil syndrome (KFS) is the presence of at least one congenitally fused cervical segment. Studies have reported the potential risk of cervical injury from hypermobility associated with the nonfused cervical segment in KFS. The manifestation of a cervical disc herniation in the pediatric KFS patient is rare. To the authors' knowledge, the development of a symptomatic cervical herniated disc attributed to mechanical fatigue following a high-impact activity has not been addressed in the literature with respect to the pediatric KFS patient having extensive cervical fusion and a hypermobile segment.

METHODS

A 16.8-year-old KFS boy with occipitalization of C1 and fusion of C2-C3 and C4-T1 presented with myelopathy, severe cord compression, and myelomalacia stemming from a left-sided herniated cervical disc at C3-C4 with onset following an 8-foot high rooftop jump. On radiographic evaluation, the patient's C3-C4 segment was hypermobile.

RESULTS

The patient was operatively managed via a same-day combined posterior-anterior procedure. The posterior aspect of the procedure entailed a posterior lateral mass plate-screw fixation at C3-C4 with autologous iliac crest bone fusion. Anteriorly, a discectomy was performed at C3-C4 with application of an interbody tricortical autograft. After surgery, the patient wore a halo vest for 3 months, followed by a soft collar for an additional 3 months. On final follow-up at 39 months, the patient was asymptomatic with no instrumentation-related complications, fusion of the posterior graft-bed and anterior interbody graft was noted, and cervical alignment was maintained.

CONCLUSIONS

A hypermobile segment in the pediatric KFS patient is a risk factor that may lead to cord compression. A symptomatic herniated cervical disc may develop from an excessive mechanical load stress in a pediatric KFS patient with multiple fused segments. In such a patient, a same-day combined posterior-anterior procedure provides cord decompression and stabilizes the spine with a favorable outcome.