Surgical treatment for atlantoaxial subluxation with myelopathy in spondyloepiphyseal dysplasia congenita

Surgical treatment of atlantoaxial dysplasia and scoliosis in spondyloepiphyseal dysplasia congenita: A case report

BACKGROUND

Spondyloepiphyseal dysplasia congenita (SEDC) is a rare autosomal dominant hereditary disease caused by COL2A1 mutations. SEDC primarily involves the skeletal system, with typical clinical manifestations, including short stature, hip dysplasia, and spinal deformity. Due to the low incidence of SEDC, there are only a few case reports regarding the surgical treatment of SEDC complicated with spinal deformities.

CASE SUMMARY

We report a case of a 16-year-old male patient with SEDC. He presented with typical short stature, atlantoaxial dysplasia, scoliosis, and hip dysplasia. Cervical magnetic resonance imaging showed spinal canal stenosis at the atlas level and cervical spinal cord compression with myelopathy. The scoliosis was a right thoracic curve with a Cobb angle of 65°. He underwent atlantoaxial reduction, decompression, and internal fixation from C1–C2 to relieve cervical myelopathy. Three months after cervical surgery, posterior correction surgery for scoliosis was performed from T3 to L4. Scoliosis was corrected from 66° to 8° and remained stable at 2-year follow-up.

CONCLUSION

This is the first case report of a patient with SEDC who successfully underwent surgery for atlantoaxial dysplasia and scoliosis. The study provides an important reference for the surgical treatment of SEDC complicated with spinal deformities.

Pediatric spinal instrumentation

This article reviews the evolution of spinal instrumentation in the pediatric age group, starting with the cervical spine and atlantoaxial area and ending with the lower spine. The congenital and the acquired conditions which require instrumentation are described. The technical details regarding pediatric instrumentation are alluded to, and finally an attempt is made to predict the future of spinal instrumentation in this age group.

Cervical Instability and Quadriparesis Requiring Stabilization in Pediatric Patient Caused by a Mutation in COL2A1

A 3-year-old male with no past medical history presented with flaccid plegia of his upper extremities and significant weakness in his lower extremities after wrestling with his brother. Cervical spine magnetic resonance imaging was consistent with cord edema and intraparenchymal hemorrhage at C1-C2. A nonossified tissue mass at the expected location of the upper dens created narrowing of the canal at the C1-2 level and mass effect on the cord. Head computed tomography showed periventricular leukomalacia. Initial findings favored dysplasia of the odontoid with associated soft tissue mass/pannus caused by a possible underlying genetic or metabolic bone dyscrasia. The patient underwent suboccipital craniotomy/C1 laminectomy and occiput to C4 fusion, for decompression and stabilization. Genetic testing showed a COL2A1 collagen disorder, with the child harboring a de novo mutation for c.3455 G>T (p.G1152V). The patient was discharged to inpatient acute rehabilitation, with gradual improvement in strength in all 4 extremities.

Exploring and expanding the phenotype and genotype diversity in seven Chinese families with spondylo-epi-metaphyseal dysplasia

Spondylo-epi-metaphyseal dysplasia (SEMD) is a heterogeneous group of disorders with different modes of inheritance and is characterized by disproportionate or proportionate short stature. To date, more than 30 disease-causing genes have been identified, and different types of SEMD exhibit greatly overlapping clinical features, which usually complicate the diagnosis. This study was performed to expand the clinical and molecular spectrum of SEMD among Chinese subjects and to explore their potential phenotype–genotype relations. We enrolled seven families including 11 affected patients with SEMD, and their clinical, radiographic, and genetic data were carefully analyzed. All the seven probands showed different degrees of short stature, and each of them exhibited additional specific skeletal manifestations; four probands had extraosseous manifestations. X-rays of the seven probands showed common features of SEMD, including vertebral deformities, irregular shape of the epiphysis, and disorganization of the metaphysis. Seven variants were identified in TRPV4 (c.694C> T, p.Arg232Cys), COL2A1 (c.654 + 1G > C; c.3266_3268del, p.Gly1089del), CCN6 (c.396 T> G, p.Cys132Trp; c.721 T>C, p.Cys241Arg), SBDS (c.258 + 2T> C), and ACAN (c.1508C> A, p.Thr503Lys) genes, and two of them were novel. Two families with TRPV4 variants showed considerable intrafamily and interfamily heterogeneities. In addition, we reported one case of SEMD with a severe phenotype caused by ACAN gene mutation. Our study expands the phenotype and genetic spectrum of SEMD and provides evidence for the phenotype–genotype relations, aiding future molecular and clinical diagnosis as well as procreative management of SEMD.

Familial Aggregation of a Novel Missense Variant of COL2A1 Gene Associated with Short Extremities: Case Report and Review of the Literature

We present two cases of family members (first cousins) with short extremities caused by a novel variant of COL2A1 gene (NM_001844.5). Case 1 description: A 29-year-old woman presented in her first pregnancy for a second trimester anomaly scan at 23 weeks of gestation. Fetal long bones were measured below the third centile for gestational age. Follow-up scans revealed fetal long bone growth deceleration. Initial genetic work-up was negative and the rest of the maternal follow-up was unremarkable. A male baby weighing 3180 g was delivered at 39 weeks and 4 days of gestation. Case 2 description: A 33-year-old pregnant woman presented for a routine second trimester anomaly scan at 20 weeks and 4 days of gestation. All fetal measurements were appropriate for the gestational age. The routine growth scan performed at 32 weeks showed fetal long bone measurements below the third centile for gestational age, while the follow-up growth scan at 36 weeks and 4 days of gestation revealed consistent, below the third centile, fetal long bone growth. Given that the fetuses of these two cases were related (first cousins), whole exome sequencing (WES) was performed on Case 2. WES revealed a novel heterozygous missense variant c.1132G>A (p. Gly378Ser) of COL2A1 gene (NM_001844.5). Subsequently, targeted genetic sequencing for the variant was performed on Case 1 and the same novel variant was found. Targeted sequencing revealed the same variant in the mother of Case 1 and the father of Case 2 (siblings). A female baby weighing 3200 g was delivered at 40 weeks and 4 days of gestation.

Management of Craniocervical Instability in Spondyloepiphyseal Dysplasia Congenita: Assessment of Literature and Presentation of Two Cases

Spondyloepiphyseal dysplasia congenita (SEDC) is a rare autosomal dominant skeletal dysplasia resulting in impairment of type II collagen function. Phenotypically, this results in various skeletal, ligamentous, ocular, and otologic abnormalities. Platyspondyly, scoliosis, ligamental laxity, and odontoid hypoplasia are common, resulting in myelopathy in a high number of patients due to atlantoaxial instability. Despite patients undergoing surgical fixation, complication rates such as nonunion have been reported to be high. Here within, we present two patients treated with occipitocervical fusion for atlantoaxial instability and early symptoms of progressive myelopathy. We additionally provide a detailed review of the literature to inform practitioners of the spinal manifestations and clinical considerations in SEDC.

Extreme Genu Recurvatum Deformity in a Pediatric Patient With Spondyloepiphyseal Dysplasia: Gradual Correction With Z-plates and Hexapod Frame

Spondyloepiphyseal dysplasia is a type II collagenopathy with resulting spinal and extremity deformities. The clinical manifestations include short stature, hearing loss, kyphoscoliosis, and complex knee deformities. Genu recurvatum can be a challenging surgical problem, especially when the deformity is severe. In this report, we present a case of severe genu recurvatum in a 14-year-old female that was treated with a pediatric circular fixator with the addition of two z-plates. At one year follow-up, the patient demonstrated improved knee range of motion, tibial alignment with the radiographic union, and good ambulatory ability. The hexapod fixator with the use of two Z-plates may help ensure that appropriate ring strut angles are achieved. Larger studies regarding the efficacy of this treatment option in spondyloepiphyseal dysplasia are required.

Pediatric cervical kyphosis in the MRI era (1984-2008) with long-term follow up: literature review

OBJECTIVE

Cervical kyphosis is rare in the pediatric population. It may be syndromic or acquired secondary to laminectomy, neoplasia, or trauma. Regardless, this should be avoided to prevent progressive spinal deformity and neurological deficit. Long-term follow-up is needed to evaluate fusion status, spine growth, potential instability, and neurological function.

METHODS AND MATERIALS

A retrospective review of 27 children (6 months to 16 years) with cervical kyphotic deformity was performed and limited to the MRI era until 2008, to provide a long-term follow-up after which complex instrumentation was available. There were 27 patients, 19 syndromic (average age 5.36 years), and 8 non-syndromic (average age 14 years). Syndromes encountered were spondyloepiphyseal dysplasia (SED) 4, spondylometaphyseal dysplasia 1, unnamed collagen abnormality syndrome 1, osteogenesis imperfecta (OI) 2, Aarskog syndrome 1, Weaver syndrome 1, Larsen syndrome 1, multiple cervical level disconnection syndrome 1, Klippel-Feil 3, congenital absence of C2 pars 4. Non-syndromic cases; 2 with neurofibromatosis (NF1) and prevertebral tumors, fibromatosis 1, spontaneous kyphosis 1, and postlaminectomy 4. Factors considered were age, pathology, flexibility on cervical spine dynamic films, reduction with traction and spinal cord compression. Patients with flexible kyphosis underwent dorsal fixation. Children with non-flexible ventral compression/kyphosis had crown halo traction. Irreducible kyphosis had ventral decompression and fusion as well as dorsal fusion. Eleven of 19 syndromic children with flexible and reducible kyphosis underwent dorsal fixation alone. Four of 8 non-syndromic (2 NF1) needed ventral and dorsal approaches.

RESULTS

The preoperative deformity (global and local Cobb angles) as well as neurological status improved. Growth during follow-up was not impaired, and we did not encounter instability or junctional kyphosis. The only complications were seen in syndromic patients. One patient with SED showed delayed cantilever bending of the ventral fusion mass requiring reoperation, and 1 other OI child had left C5 and C6 nerve root weakness after anterior C4 and C5 decompression which resolved over 1 year. One child with SED developed cervicothoracic junction scoliosis 18 years later after thoracic scoliosis surgery.

CONCLUSIONS

Syndromic pathology presented early with neurological dysfunction and 24% had rigid kyphosis. An attempt at traction/reduction was successful as in Tables 1 and 2. The majority exhibited long-term improvement in kyphosis and function. A treatment algorithm and literature review is presented. Table 1 Motor function of the modified Japanese Orthopedic Association (JOA) score in children [24, 37] Score Upper extremity •Unable to move hands or feed oneself 0 •Can move hands; unable to eat with spoon 1 •Able to eat with spoon with difficulty 2 •Able to use spoon; clumsy with buttoning 3 •Healthy; no dysfunction 4 Lower extremity •Unable to sit or stand 0 •Unable to walk without cane or walker 1 •Walks independently on level floor but needs support on stairs 2 •Capable to walking, clumsy 3 •No dysfunction 4 Table 2 Pediatric cervical kyphosis-preoperative evaluations Case ID, year presented Age Sex Diagnosis Presentation Imaging Apex Cobb angle degree Reducibility Preop traction Syndromic #1 2003 4 years M SED Progressive quadriparesis Bladder incontinence Severe C2-4 kyphosis with cord compression C3-4 85° No No #2 2001 3 years M SED Progressive quadriparesis C2-3 kyphosis. No dorsal C2. Buckled cord C2-3 25° No No Recurrent weakness after recovery 2 years later Kyphosis at fusion site C2-3 33° No No #3 1997 13 years M SED Neck pain. Hand weakness. Thoracic scoliosis C1-3 kyphosis Os odontoideum C2-3 30° Yes No #4 2006 6 years F SED Tingling in hands Bladder incontinence Deformed C2 body and odontoid C1-2 instability C2-3 27° Yes No #5 1997 4 years M SMD Quadriparesis. Previous C2-3 kyphosis with O-C3 dorsal fusion elsewhere Fixed C1-2 dislocation. C2-3 kyphosis. O-C4 fusion C2 35° Partial Yes 4 days #6 2007 13 years F Syndromic collagen abnormality Neck pain. Leg length discrepancies. T-L scoliosis. Quadriparesis Bilateral C2 and partial C3 spondylolysis C-T levoscoliosis C2-3 35° Partial Yes 4 days #7 2003 14 years F Osteogenesis imperfecta (OI) Only able to use right upper extremity C3-5 kyphosis. Canal diameter 4 mm at C4 C4 25° No No #8 1989 3 years F OI - Bruck's syndrome Quadriparesis age 9 months. Had C1-C3 posterior decompression and fusion elsewhere Progressive kyphosis Worse weakness Bend in fusion C1-2 40° No No #9 1996 11 years M Aarskog syndrome Neck pain with limited neck motion Cervical myelopathy Psychomotor delay C4-5 spondylolysis C5-6 kyphosis C5 30° No Yes 3 days #10 1989 3½ years F Weaver syndrome Quadriparesis age 2 years. Elsewhere C1-C3 dorsal rib fusion and wires Fusion failure C2-3 subluxation Cord compression C2-3 3° Yes Yes 1 day #11 1986 11 years F Larsen syndrome Neck pain in extension Quadriparesis C2-3 kyphosis. Deformed bodies C2-5 Os odontoideum C1-2 instability C2-3 28° Yes Yes 1 day #12 1996 5 years M Multilevel cervical disconnect syndrome Horner pupil on right Small right arm Quadriparesis C4, C5 vertebral bodies behind C5 C5 body in canal Left vertebral artery in C5 body C4-5 35° No No #13 1985 3 years F Klippel-Feil Neck pain. Weak hands Atlas assimilation C3-4 kyphosis No posterior bony arches C3, C4 C3-4 40° Yes No #14 1994 3 years F Klippel-Feil Unable to sit. Floppy. Quadriparesis C2-3 kyphosis No posterior arches C2-3 and L4 C2-3 45° Yes No #15 1993 11 months F Tuberous sclerosis Spondylolysis C2 Salam seizures Quadriparesis No pars C2 C2-3 kyphosis C2-3 30° Yes No #16 1998 2 years M C2 spondylolysis Quadriparesis, arms worse than legs C2 spondylolysis C2-3 kyphosis C2-3 35° Yes No #17 1998 6 months M C2 spondylolysis Failure to thrive Apneic spells Weak in arms after endoscopy C2-3 kyphosis No C2 lamina Cord compression C3-4 on MRI C2-3 45° Yes No #18 1990 4 years F C2 spondylolysis Developmental delay Quadriparesis C2 spondylolysis C2-3 kyphosis C3 45° Yes No #19 1994 4 years F Klippel-Feil No posterior C2 Torticollis age 6 mo Quadriparesis C2-3 kyphosis No posterior arch C2 Fused C3-4 bodies C2-3 45° Yes No Non-syndromic #20 1996 15 years M NF1. Ventral prevertebral plexiform neurofibroma Neck pain Weak arms Cervical myelopathy C4-5 kyphosis Cord draped over C4-5 Enhanced prevertebral tumor C4-5 60° Partial Yes 4 days #21 1996 6 years M NF1 Age 6 mo had C1-3 laminectomies elsewhere Progressive kyphosis Quadriparesis C3-5 plexiform neurofibromas C2-4 kyphosis C3-4 45° No No #22 1993 11 years M "Fibromatosis" Neck pain Gag ↓ Right hemiparesis C2 body and odontoid curved dorsally C2-3 kyphosis C2 40° No Yes 3 days #23 2007 13 F Mid-cervical kyphosis Neck pain Unable to move neck C3-4 kyphosis C3-4 45° Yes Halo vest elsewhere 6 weeks Repeat traction on referral #24 1998 12 years M Chiari I Syringohydromyelia Difficulty swallowing Quadriparesis Previous posterior fossa and C1-3 decompression Basilar invagination C3-4 kyphosis C3-4 50° Yes Halo traction 3 days #25 1994 16 years M Chiari I. SHM Difficult speech Quadriparesis Previous posterior fossa and C1-4 laminectomies C3-4 kyphosis Basilar invagination C3-4 55° Yes Halo traction 3 days #26 2002 11 years M Chordoma C3-5 Initial quadriparesis improved after posterior decompression then worse Dorsal and lateral tumor C3-4 C3-4 20° Yes Traction 3 days #27 2006 13 years M C4 lamina Aneurysmal bone cyst Neck and shoulder pain C4 laminectomy for tumor resection Worse 4 months later C4-5 kyphosis C3-4 40° Yes No Table 3 Pediatric cervical kyphosis-postoperative evaluations Case ID Diagnosis Treatment-operation Complication PO orthosis F/U time Fusion status Preop Cobb Postop Cobb Preop JOA Postop JOA Comments Syndromic #1 SED Crown halo traction 1. Median mandibular glossotomy. Resection C2-3 bodies with rib graft fusion 2. Dorsal O-C3 rib graft fusion None Halo vest 3 months Soft collar 3 months 8 years Complete anterior and posterior fusion 85° 10° 2 8 Complete neurological recovery #2 SED Crown halo traction 1. Median mandibular glossotomy. C2-4 corpectomies. C2-5 anterior rib graft fusion Recurrent weakness 2 years s later Halo vest 3 months 2 years Fused 25° 20° 4 5 T. scoliosis. Cardiac abnormalities. Walking then quadriparesis Redo ventral resection and C1-4 iliac bone graft Worsening quadriparesis Minerva brace 1 year 18 years Fused 33° 15° 3 5 Much improved in 6 months #3 SED Crown halo traction Dorsal O-C4 fusion with loop and rib graft None Miami J collar 3 months 10 years Fused 30° 13° 4 7 Works in bookstore #4 SED Crown halo traction Dorsal O-C3 fusion with loop and rib graft 4 years later developed C-T scoliosis after T. scoliosis surgery Miami J collar 3 months 14 years Fused 27° 5° 5 7 C-T scoliosis developed after thoracic scoliosis correction #5 SMD Crown halo traction Transoral C2 odontoid resection None Minerva brace 6 months 20 years No from preop status 35° 10° 1 4 In wheelchair. Works as programmer #6 Collagen abnormality Crown halo traction C2-5 ACDF C2-5 plate with C3-4 lag screws Junctional kyphosis 7 years later after scoliosis correction Miami J collar 6 weeks 12 years Fused 36° 5° 4 7 Abnormal vertebral arteries. Thoracic outlet syndrome May-Thurner syndrome #7 OI Crown halo traction C3-5 corpectomies C2-6 Orion plate with iliac crest graft None Soft collar 4 years Fused 25° 30° 1 5 Restrictive lung disease. Multiple fractures Expired #8 OI - Bruck syndrome 1. Redo C1-2 dorsal rib graft fusion No change Molded Minerva brace 4 years Fused 40° 35° 3 4 Increased weakness age 7 2. 11 years age anterior C3-7 decompression and plate C3-7 Worsening left deltoid and biceps function Molded Minerva brace 30 years Fused 52° 34° 3 5 Lives alone. Wheelchair. Computer technologist Uses hands well #9 Aarskog syndrome Crown halo traction C2-6 anterior cervical fusion with iliac crest graft None Molded Minerva brace 20 years Fused 30° 14° 4 7 Works on a farm. No myelopathy. Syndrome in family #10 Weaver syndrome Crown halo traction Redo C1-4 dorsal rib graft fusion None Miami J collar 2 years Fused 3° 10° 2 5 Neuroblastoma age 3 months. Chemotherapy Stable #11 Larsen syndrome Crown halo traction O-C5 dorsal fusion None Halo vest 6 weeks Miami J 3 months 6 years Fused 28° 10° 3 7 Doing well #12 Multilevel cervical disconnect syndrome Crown halo traction C5 corpectomy C4-6 iliac bone fusion anteriorly Dorsal C4-6 fusion None Halo vest 3 months 5 years Fused 35° 5° 3 7 Persistent Horner pupil #13 Klippel-Feil Crown halo traction C2-6 posterior rib graft fusion None Halo vest 3 months 19 years Fused 40° 12° 3 7 Hearing loss Genitourinary abnormalities Sprengel's deformity #14 Klippel-Feil Crown halo C2-5 dorsal rib graft fusion None Halo vest 3 months 35 years Fused 45° 10° 1 6 Hearing loss Genitourinary abnormalities #15 Tuberous sclerosis Spondylolysis C2 C1-4 dorsal interlaminar rib fusion None Halo vest 3 months 6 years Fused 30° 5° 1 6 Psychomotor delay #16 C2 spondylolysis C1-4 dorsal interlaminar fusion None Halo vest 3 months 4 years Fused 35° 10° 2 6 Recovered full function in one year #17 C2 spondylolysis Tracheostomy Molded cervicothoracic brace None Mold brace 4 years 6 years Formed C2 posterior arches 45° 20° 1 3 Reformed C2 at 4 years on CT Parents did not wish surgery #18 C2 spondylolysis Intraoperative traction C1-3 dorsal rib graft fusion None Neck brace 4 months 8 years Fused 45° 12° 2 5 Developed C2 posterior elements #19 Klippel-Feil Intraoperative traction O-C4 fusion with rib graft None Molded brace 6 months 1 years Fused O-C2 dorsally 45° 16° 1 4 Able to sit and use hands Non-syndromic #20 NF1 Resection of ventral tumor C3-6 C4-5 corpectomies; C4-5 iliac graft; C3-7 Orion plate None Halo vest 6 weeks 14 years Fused 60° 15° 3 7 Recovered in 6 weeks. Works on a farm #21 NF1 Intraoperative traction Resect prevertebral tumor C2-5 kyphectomies; C2-6 anterior fusion iliac crest None Halo vest 3 months 2 years Fused 45° 20° 3 5 Initial C1-3 decompression done elsewhere #22 Fibromatosis 1. Transoral C2 decompression 2. Dorsal O-C3 fusion with loop None Brace 3 months 12 years Fused 40° 12° 4 6 Age 2 years had neck mass resected. Diagnosis "fibromatosis" #23 Mid-cervical kyphosis Traction C2-5 lateral mass fusion with screws, rods and rib grafts Worse after removal of initial traction Brace 3 months 8 years Fused 45° 15° 7 8 Doing well #24 Chiari I SHM Intraoperative traction O-C5 rib graft fusion None Halo vest 3 months 21 years Fused 50° 7° 2 6 Facets atrophied C2, C3 at surgery #25 Chiari I SHM Intraoperative traction O-C5 dorsal fusion with loop and rib None Miami J brace 4 months 22 years Fused 55° 10° 3 6 Facets atrophied C2-4 at surgery #26 Chordoma C3-4 1. Dorsal lateral C3-6 fusion 2. C2-5 anterior fusion with iliac bone None Miami J brace 6 months 18 years Fused 20° 12° 5 8 Weak in hands after initial surgery elsewhere #27 ABC tumor C4 Anterior C3-5 fusion with plate and bone None Miami J brace 4 weeks 12 years Fused 40° 15° 5 8 No recurrence SED spondyloepiphyseal dysplasia, SMD spondylometaphyseal dysplasia, JOA Japanese Orthopedic Association, MRI magnetic resonance imaging, SHM syringohydromyelia, NF1 neurofibromatosis type 1, f/u follow up, OI osteogenesis imperfecta, CT computed tomography, JK junctional kyphosis.

The relationship between atlas hypoplasia and os odontoideum in children with Down syndrome: a preliminary case report

The purpose of this study was to evaluate the relationship of os odontoideum and the size of atlas among children with Down syndrome. Understanding the risk of developing myelopathy in asymptomatic cases is important in children with Down syndrome. Children with os odontoideum are considered to be at high risk of developing myelopathy because of instability; however, in cases that are complicated by atlas hypoplasia, the risk remains the same, regardless of instability. This retrospective case-control study assessed atlas hypoplasia in children with Down syndrome with or without os odontoideum. We retrospectively assessed the records of 59 patients (36 males and 23 females) with Down syndrome who underwent spinal X-ray evaluations at our hospital. The average age at examination was 5.0 years (range, 4-7). We evaluated the following radiologically: the presence of os odontoideum; atlas-dens interval; space available for the spinal cord at the atlas level (C1SAC); instability index; sagittal atlas diameter (SAD) as an index of atlas hypoplasia and C5 level SAC (C5SAC), adjusted for child growth. Os odontoideum was present in seven cases (12%). Between the groups with and without os odontoideum, there was no significant difference in age (mean, 5.2 vs. 5.0 years) or male/female ratio (57 vs. 62% males). The SAD/C5SAC (mean, 1.6 vs. 1.9) was significantly smaller in the group with os odontoideum than in those without os odontoideum. The instability index was not significantly different between the two groups. Children with Down syndrome and os odontoideum have small SAD. Evaluations for atlas hypoplasia are necessary.

An unusual injury mechanism of atlantoaxial dislocation: illustrative case

BACKGROUND

Atlantoaxial dislocation (AAD) is a rare and potentially life-threatening condition. Various underlying mechanisms of injury are described in the literature. Here, the authors report an unusual nontraumatic injury mechanism of AAD in a 12-year-old patient.

OBSERVATIONS

A 12-year-old boy presented with intolerable neck pain and numbness in both upper limbs. The patient’s symptoms had started 2 months after the initiation of online classes during the coronavirus disease 2019 pandemic without a history of trauma. He used a computer for personal study and online classes for prolonged hours with no respite. On physical and radiological evaluation, he was diagnosed with AAD. Before surgery, skull traction was applied to reduce the dislocation and posterior C1 lateral mass screw and C2 pedicle screw fixation was performed. An optimal clinical outcome was achieved with no postoperative complications. A preoperative visual analog scale score of 8.0 was reduced to 0 postoperatively.

LESSONS

A prolonged fixed neck posture is an unusual underlying cause of AAD. Posterior C1 lateral mass and C2 pedicle screw fixation results in an optimal clinical outcome.

Posterior occipitocervical instrumented fusion for atlantoaxial instability in a 27-month-old child with Down syndrome: illustrative case

BACKGROUND

Upper cervical spine instability is one of the most serious orthopedic problems in patients with Down syndrome. Despite the recent advancement of instrumentation techniques, occipitocervical fusion remains technically challenging in the very young pediatric population with small and fragile osseous elements.

OBSERVATIONS

A 27-month-old boy with Down syndrome was urgently transported to the authors’ hospital because of difficulty in standing and sitting, weakness in the upper limbs, and respiratory distress. Radiographs showed os odontoideum, irreducible atlantoaxial dislocation, and substantial spinal cord compression. Emergency posterior occipitoaxial fixation was performed using O-arm navigation. Improvement in the motor paralysis of the upper left limb was observed from the early postoperative period, but revision surgery was needed 14 days after surgery because of surgical site infection. The patient showed modest but substantial neurological improvement 1 year after the surgery.

LESSONS

There are several clinical implications of the present case. It warns that Down syndrome in the very young pediatric population may lead to rapid progression of spinal cord injury and life crisis. This 27-month-old patient represents the youngest case of atlantoaxial instability in a patient with Down syndrome. O-arm navigation is useful for inserting screws into very thin pedicles.

Atlanto-axial rotary instability (Fielding type 1): characteristic clinical and radiological findings, and treatment outcomes following alignment, fusion, and stabilization

Atlanto-axial instability (AAI) is common in the connective tissue disorders, such as rheumatoid arthritis, and increasingly recognized in the heritable disorders of Stickler, Loeys-Dietz, Marfan, Morquio, and Ehlers-Danlos (EDS) syndromes, where it typically presents as a rotary subluxation due to incompetence of the alar ligament. This retrospective, IRB-approved study examines 20 subjects with Fielding type 1 rotary subluxation, characterized by anterior subluxation of the facet on one side, with a normal atlanto-dental interval. Subjects diagnosed with a heritable connective tissue disorder, and AAI had failed non-operative treatment and presented with severe headache, neck pain, and characteristic neurological findings. Subjects underwent a modified Goel-Harms posterior C1-C2 screw fixation and fusion without complication. At 15 months, two subjects underwent reoperation following a fall (one) and occipito-atlantal instability (one). Patients reported improvement in the frequency or severity of neck pain (P < 0.001), numbness in the hands and lower extremities (P = 0.001), headaches, pre-syncope, and lightheadedness (all P < 0.01), vertigo and arm weakness (both P = 0.01), and syncope, nausea, joint pain, and exercise tolerance (all P < 0.05). The diagnosis of Fielding type 1 AAI requires directed investigation with dynamic imaging. Alignment and stabilization is associated with improvement of pain, syncopal and near-syncopal episodes, sensorimotor function, and exercise tolerance.

A novel COL2A1 mutation causing spondyloepiphyseal dysplasia congenita in a Chinese family

Background

Spondyloepiphyseal dysplasia congenita is an autosomal dominant cartilaginous dysplasia characterized by short trunk, abnormal epiphysis, and flattened vertebral body. Skeletal features of SEDC are present at birth and evolve over time. Other features of SEDC include myopia and/or retinal degeneration with retinal detachment and cleft palate. A mutation in the COL2A1 gene located in 12q13.11 is considered as one of the important causes of SEDC. In 2016, Barat‐Houari et al. reported a large number of COL2A1 mutations. Among them, a non‐synonymous mutation in COL2A1 exon 37, c.2437G>A (p. Gly813Arg), has been reported to cause SEDC in only one patient from France so far.

Methods

We followed up a patient with SEDC phenotype and his family members. The clinical manifestations, physical examination and imaging examination, including X‐ray, CT and MRI, were recorded. The whole‐exome sequencing was used to detect the patients' genes, and the pathogenic genes were screened out by comparing with many databases.

Results

We report a Chinese patient with SEDC phenotype characterized by short trunk, abnormal epiphysis, flattened vertebral body, narrow intervertebral space, dysplasia of the odontoid process, chicken chest, scoliosis, hip and knee dysplasia, and joint hypertrophy. Gene sequencing analysis showed that the patient had a heterozygous mutation (c.2437G>A; p. Gly813Arg) in the COL2A1 gene. No COL2A1 mutation or SEDC phenotype was observed in his family members. This is the first report of SEDC caused by this mutation in an East Asian family.

Conclusion

This report provides typical clinical, imaging, and genetic evidence for SEDC, confirming that a de novo mutation in the COL2A1 gene, c.2437G>A (p. Gly813Arg), causes SEDC in Chinese population.

Results of Conservative and Surgical Management in Children with Idiopathic and Nonidiopathic Os Odontoideum

OBJECTIVE

The outcomes of conservative and operative treatment of os odontoideum in children remain unclear. Our objective was to study the outcomes of conservative and surgical treatment of idiopathic os odontoideum in children and compare these outcomes in age- and treatment-matched nonidiopathic children with os odontoideum.

METHODS

A retrospective multicenter review identified 102 children with os odontoideum, of whom 44 were idiopathic with minimum 2-year follow-up. Ten patients were treated conservatively, and 34 underwent spinal arthrodesis. Both groups were matched with nonidiopathic patients by age and type of treatment. Cervical arthrodesis was recommended for patients with increased atlantoaxial distance or reduced space available for the cord in flexion-extension radiographs.

RESULTS

All 20 children undergoing conservative treatment remained asymptomatic during follow-up, but 1 nonidiopathic patient developed cervical instability. The idiopathic group had significantly less severe radiographic cervical instability and less neurologic complications than the nonidiopathic group (P < 0.05 for all comparisons). Thirty-three (97%) patients in the idiopathic group and 32 (94%) patients in the nonidiopathic group (94%) had spinal fusion at final follow-up (P = 0.55). The risk of complications (15% vs. 41%; odds ratio 0.234, 95% confidence interval 0.072-0.757, P = 0.015) and nonunion (6% vs. 24%; odds ratio 0.203, 95% confidence interval 0.040-0.99, P = 0.040) were significantly lower in the idiopathic than in the nonidiopathic group. Idiopathic children undergoing rigid fixation achieved spinal fusion.

CONCLUSIONS

Idiopathic patients with stable atlantoaxial joint at presentation remained asymptomatic and intact during conservative treatment. Idiopathic children with os odontoideum undergoing spinal arthrodesis had significantly fewer complications and nonunion than nonidiopathic children.

LEVEL OF EVIDENCE

III.

Clinical and Molecular Characterization and Discovery of Novel Genetic Mutations of Chinese Patients with COL2A1-related Dysplasia

COL2A1-related disorders represent a heterogeneous group of skeletal dysplasias with a wide phenotypic spectrum. Our aim is to characterize the clinical and molecular phenotypes of Chinese patients with COL2A1-related dysplasia and to explore their phenotype-genotype relations. Clinical data were collected, physical examinations were conducted, and X-ray radiography and genetic analyses were performed in ten families involving 29 patients with COL2A1-related dysplasia. Nine mutations were identified in COL2A1, including five novel (c.816+6C>T, p.Gly246Arg, p.Gly678Glu, p.Gly1014Val and p.Ter1488Gln) and four reported previously (p.Gly204Val, p.Arg275Cys, p.Gly504Ser and p.Arg719Cys). Based on clinical features and molecular mutations, the ten families were classified into five definite COL2A1-related disorders: four families with spondyloepiphyseal dysplasia congenita (SEDC), three with osteoarthritis with mild chondrodysplasia (OSCPD), one with Czech dysplasia, one with Kniest dysplasia, and one with epiphyseal dysplasia, multiple, with myopia and deafness (EDMMD). Based on genetic testing results, prenatal diagnosis and genetic counseling were accomplished for one female proband with OSCDP. Chinese patients with OSCDP, Czech dysplasia and EDMMD caused by COL2A1 mutations were first reported, expanding the spectrum of COL2A1 mutations and the phenotype of COL2A1-related disorders and providing further evidence for the phenotype-genotype relations, which may help improve procreative management of COL2A1-related disorders.

Os Odontoideum in Children: Treatment Outcomes and Neurological Risk Factors

BACKGROUND

Treatment outcomes and risk factors for neurological deficits in pediatric patients with an os odontoideum are unclear.

METHODS

We reviewed the data for 102 children with os odontoideum who were managed at 11 centers between 2000 and 2016 and had a minimum duration of follow-up of 2 years. Thirty-one children had nonoperative treatment, and 71 underwent instrumented posterior cervical spinal arthrodesis for the treatment of C1-C2 instability. Nonoperative treatment consisted of observation (n = 29) or immobilization with a cervical collar (n = 1) or halo body jacket (n = 1). Surgical treatment consisted of atlantoaxial (n = 50) or occipitocervical (n = 21) arthrodesis. One patient also underwent transoral odontoidectomy.

RESULTS

Thirty children (29%) presented with neurological deficits, 28 of whom had radiographic atlantoaxial instability (atlantoaxial distance >5 mm) or limited space (≤13 mm) available for the spinal cord (risk ratio, 7.8 [95% confidence interval, 2.0 to 31] compared with children with no radiographic risk factors). The 27 children without neurological deficits or atlantoaxial instability at presentation underwent nonoperative treatment and remained asymptomatic. Of the initial nonoperative cohort, one child developed atlantoaxial instability, and another had a persistent neurological deficit; both children underwent spinal arthrodesis during the study period. One child with cervical instability declined surgery and remained asymptomatic. Spinal fusion occurred in 68 patients in the surgical group by the end of the study period (mean, 3.7 years; range, 2.0 to 11.8 years). Surgical complications occurred in 21 children, including nonunion in 12, new neurological deficits in 4, cerebrospinal fluid leak in 2, symptomatic instrumentation requiring removal 2, and vertebral artery injury in 1. Nine children underwent revision surgery. In the surgical group, Japanese Orthopaedic Association neurological function scores improved significantly from preoperatively to the latest follow-up for the upper extremities (p = 0.026) and lower extremities (p = 0.007).

CONCLUSIONS

The risk of developing a neurological deficit was strongly associated with atlantoaxial instability and limited space available for the spinal cord in children with os odontoideum. Nonoperative treatment was safe for asymptomatic patients without atlantoaxial instability. Spinal arthrodesis resolved the neurological deficits of children with symptomatic os odontoideum.

LEVEL OF EVIDENCE

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

Best practice guidelines regarding diagnosis and management of patients with type II collagen disorders

PURPOSE

Skeletal dysplasias comprise a heterogeneous group of inherited disorders of development, growth, and maintenance of the human skeleton. Because of their relative rarity and wide phenotypic variability, patients should be accurately identified, uniformly assessed, and managed by clinicians who are aware of their potential complications and possess the knowledge and resources to treat them effectively. This study presents expert guidelines developed to improve the diagnosis and management of patients with type II collagen skeletal disorders to optimize clinical outcomes.

METHODS

A panel of 11 multidisciplinary international experts in the field of skeletal dysplasia participated in a Delphi process, which comprised analysis of a thorough literature review with subsequent generation of 26 diagnosis and care recommendations, followed by two rounds of anonymous voting with an intervening face-to-face meeting. Those recommendations with more than 80% agreement were considered as consensual.

RESULTS

After the first voting round, consensus was reached to support 12 of 26 (46%) statements. After the panel discussion, the group reached consensus on 22 of 24 revised statements (92%).

CONCLUSIONS

Consensus-based, expert best practice guidelines developed as a standard of care to assist accurate diagnosis, minimize associated health risks, and improve clinical outcomes for patients with type II collagen skeletal dysplasias.

The Managment of cervical spine abnormalities in children with spondyloepiphyseal dysplasia congenita: Observational study

Spondyloepiphyseal dysplasia congenita (SEDC) is an autosomal dominant disorder, characterized by disproportionate dwarfism with short spine, short neck associated with variable degrees of coxa vara. Cervical cord compression is the most hazardous skeletal deformity in patients with SEDC which requires special attention and management.Ten patients with the clinical and the radiographic phenotypes of spondyloepiphyseal dysplasia congenita have been recognized and the genotype was compatible with single base substitutions, deletions or duplication of part of the COL2A1 gene (6 patients out of ten have been sequenced). Cervical spine radiographs showed apparent atlantoaxial instability in correlation with odontoid hypoplasia or os-odontoideum.Instability of 8 mm or more and or the presence of symptoms of myelopathy were the main indications for surgery. Posterior cervical fusion from the occiput or C1-3, decompression of C1-2 and application of autorib transfer followed by halo vest immobilization have been applied accordingly.Orthopedic management of children with spondyloepiphyseal dysplasia congenita (SEDC) should begin with the cervical spine to avoid serious neurological deficits and or mortality.

Upper Cervical Fusion in Children With Spondyloepiphyseal Dysplasia Congenita

BACKGROUND

Paraplegia or death secondary to upper cervical spine instability and spinal cord compression are known consequences of spondyloepiphyseal dysplasia congenita (SEDC). Stabilization and occasionally decompression of the upper cervical spine are indicated to treat upper cervical instability and stenosis. The purpose of this study was to report the results of upper cervical spine fusion in children with SEDC who had upper cervical instability.

METHODS

Twenty children (17 females and 3 males) with SEDC who underwent upper cervical spine fusion at a mean age of 72 months were retrospectively analyzed. Three of these children were under the age of 2. Fifteen children had posterior instrumentation and fusion whereas 5 children had posterior in situ fusion without use of any implant. Thirteen of 20 children had iliac crest autograft. Radiographic and clinical results were reported.

RESULTS

The average follow-up period was 8 years and 8 months. All children with instrumentation achieved fusion. Three of 5 children who had no instrumentation had nonunion (1 child had a stable nonunion and did not need revision; 1 had a single noninstrumented revision and ended up with a stable nonunion without further intervention; and the third one had a noninstrumented revision and had to have a second, instrumented, revision to achieve fusion). Six children had thoracolumbar scoliosis or kyphoscoliosis which required surgical management.No postoperative neurological deficits were observed. Two of the 3 children with a preoperative neurological deficit showed full recovery and the third one remained unchanged. Pseudarthrosis is the main complication for the noninstrumented group. Distal junctional instability after successful fusion is seen at long-term follow-up (average=6 y) for 13% of patients in instrumented group.

CONCLUSIONS

Instrumentation and iliac bone grafting results in 100% upper cervical fusion for SEDC children who demonstrated instability before surgery.

LEVEL OF EVIDENCE

Level IV-therapeutic.

Clinical Diagnosis of X-Linked Spondyloepiphyseal Dysplasia Tarda and a Novel Missense Mutation in the Sedlin Gene (SEDL)

OBJECTIVE

Spondyloepiphyseal dysplasia tarda (SEDT) is a rare hereditary bone disease characterized by spinal and epiphyseal anomalies. We identified the disease by gene sequencing in a Chinese pedigree with SEDT.

METHODS

We extracted genomic DNA from five members of a four-generation Chinese SEDT kindred with three affected males and then analyzed the genetic mutation by PCR and DNA sequencing.

RESULTS

DNA sequencing showed that the genetic missense mutation occurred one bp upstream of exon 6 in the SEDL gene in two families, and a heterozygous mutation was found in a female carrier. In addition, no mutation was found in the other members of the family.

CONCLUSION

SEDT in this family was caused by a G/C missense mutation in exon 6 of the SEDL gene, previously not shown to be associated with X-linked SEDT.

Rigid Occipitocervical Instrumented Fusion for Atlantoaxial Instability in an 18-Month-Old Toddler With Brachytelephalangic Chondrodysplasia Punctata: A Case Report

STUDY DESIGN

Case report.

OBJECTIVE

We report here on an 18-month-old boy with brachytelephalangic chondrodysplasia punctata (BCDP), whose atlantoaxial instability was successfully managed with occipitocervical instrumented fusion (OCF) using screw and rod instrumentations.

SUMMARY OF BACKGROUND DATA

Recently, there have been a number of reports on BCDP with early onset of cervical myelopathy. Surgical OCF is a vital intervention to salvage affected individuals from the life-threatening morbidity. Despite recent advancement of instrumentation techniques, however, rigid OCF is technically demanding in very young children with small and fragile osseous elements. To our best knowledge, this is the first report on application of the instrumentation technique to a toddler patient with BCDP.

METHODS

A 16-month-old boy with BCDP presented with tetraplegia and swallow obstacle. Hypoplasia of the odontoid process and atlantoaxial instability were present in lateral radiographs. T2-weighted magnetic resonance (MR) images revealed a high signal region in the spinal cord at the C1-2 and C7-T1 levels. Cervical computed tomography (CT) showed that the pedicles and lateral masses in the cervical spine were small and immature, but the laminae were comparatively thick.

RESULTS

One week before surgery, the patient was fitted with a Halo-body jacket. We performed plate-rod placement with occipital cortical screws and C2/C3 interlaminar screws, and added an autogenous bone graft using the right 8 and 9 ribs. Rigid fixation of the occipito-cervical spine was completed successfully without major complications. Postoperative halo-body jacket immobilization was continued for 3 months, after which Aspen collar was fitted. CT confirmed occipitocervical bone fusion at 6 months after surgery. Mild clinical improvements in motor power of the affected muscles and swallowing were witnessed at 1 year postoperatively.

CONCLUSION

Rigid fixation using screw, rod, and occipital plate instrumentation was successful in an 18-month-old toddler with BCDP and atlantoaxial instability. Bone fusion was achieved at postoperative 6 months.

LEVEL OF EVIDENCE

5.

Instrumented cervical spinal fusions in children: indications and outcomes

PURPOSE

To report indications, outcomes and complications of instrumented cervical spinal fusion in a consecutive series of children at major university hospitals.

METHODS

A retrospective, single surgeon series identified 35 consecutive children with a mean follow-up (FU) of 2.5 years undergoing instrumented cervical spinal fusion between 2005 and 2015.

RESULTS

The main indications were skeletal dysplasia and trauma associated cervical instability. Surgical complications were observed in 12 (34%) patients with multiple complications in four (11%). Four (11%) children required at least one revision surgery, three for nonunion and one for graft dislodgement. All were fused at FU. Surgical complications were more common in children undergoing occipitocervical (OC) fusion than in those avoiding fusion of the OC junction (60% versus 24%) (p = 0.043). Complications were found significantly more in children operated on under the age of ten years than above (50% versus 18%) (p = 0.004). The risk of complications was not dependent on the indications for surgery (skeletal dysplasia versus trauma) (p = 0.177).

CONCLUSION

Skeletal dysplasia associated cervical instability and cervical spine injuries represented the most common indications for instrumented cervical spinal fusion in children. Complications were observed in one-third of these children and 11% required revision surgery for complications. OC spinal fusion and spinal fusion before the age of ten years are associated with higher risk of surgical complications and increased mortality than non-OC fusions and cervical spinal fusions at an older age. We urge surgeons to employ caution to the patient, timing and procedure selection when treating paediatric cervical spine.

Anterior endoscopically assisted bone grafting for iatrogenic distraction of odontoid fracture after percutaneous anterior screw fixation: A case report

RATIONALE

The complication of iatrogenic distraction of odontoid fracture after anterior screw fixation has not been reported in the literature. We treated the patient with endoscopically assisted bone grafting with good results. The new technique was not reported in the management of odontoid fracture or nonunion before.

PATIENT CONCERNS

A 22-year-old man presented with neck pain after a motorcycle crash. The cervical spine radiograph and computed tomographic scan demonstrated the base of dens displaced 2 mm anteriorly.

DIAGNOSES

Radiographic images showed a type II odontoid fracture.

INTERVENTIONS

The patient was treated by percutaneous anterior screw fixation. The postoperative radiograph and CT demonstrated an iatrogenic distraction of the odontoid with a gap of 6 mm.The follow-up radiograph did not show any sign of bone union 1 month and a half later. A revision surgery was given by anterior endoscopically assisted bone grafting. The patient was encouraged to sit out of bed immediately after the surgery with the protection of a soft cervical collar for 3 months.

OUTCOMES

No complications such as neural structures or vascular injuries were found. Bone union was achieved at the 1-year follow-up CT scans. Physical examination showed a full range of motion in the neck.

LESSONS

We reported a case of iatrogenic odontoid distraction that was managed by anterior endoscopically assisted bone grafting. It is a technically feasible and minimally invasive procedure.

Outcomes of Spinal Fusion for Cervical Kyphosis in Children with Neurofibromatosis

BACKGROUND

Cervical kyphosis may occur with neurofibromatosis type I (NF1) and is often associated with vertebral dysplasia. Outcomes of cervical spinal fusion in patients with NF1 are not well described because of the rarity of the condition. We aimed to (1) characterize the clinical presentation of cervical kyphosis and (2) report the outcomes of posterior and anteroposterior cervical fusion for the condition in these children.

METHODS

The medical records and imaging studies of 22 children with NF1 who had undergone spinal fusion for cervical kyphosis (mean, 67°) at a mean age of 11 years and who had been followed for a minimum of 2 years were reviewed.

RESULTS

Thirteen children presented with neck pain; 10, with head tilt; 9, with a previous cervical laminectomy or fusion; and 5, with a neurologic deficit. Two patients had spontaneous dislocation of the mid-cervical spine without a neurologic deficit. Eleven had scoliosis, with the major curve measuring a mean of 61°. Nine patients underwent posterior and 13 underwent anteroposterior surgery. Twenty-one received spinal instrumentation, and 1 was not treated with instrumentation. Preoperative halo traction was used for 9 patients, and it reduced the mean preoperative kyphosis by 34% (p = 0.0059). At the time of final follow-up, all spinal fusion sites had healed and the cervical kyphosis averaged 21° (mean correction, 69%; p < 0.001). The cervical kyphosis correction was significantly better after the anteroposterior procedures (83%) than after the posterior-only procedures (58%) (p = 0.031). Vertebral dysplasia and erosion continued in all 17 patients who had presented with dysplasia preoperatively. Thirteen patients had complications, including 5 new neurologic deficits and 8 cases of junctional kyphosis. Nine patients required revision surgery. Junctional kyphosis was more common in children in whom ≤5 levels had been fused (p = 0.054).

CONCLUSIONS

Anteroposterior surgery provided better correction of cervical kyphosis than posterior spinal fusion in children with NF1. Erosion of vertebral bodies continued during the postoperative follow-up period in all patients who had presented with dysplastic changes preoperatively. The cervical spine should be screened in all children with NF1. Fusion should include at least 6 levels to prevent junctional kyphosis.

LEVEL OF EVIDENCE

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

Spinolaminar Line Test as a Screening Tool for C1 Stenosis

Study Design Retrospective cohort. Objective To clarify the sensitivity of C3-C2 spinolaminar line test as a screening tool for the stenosis of C1 space available for the cord (SAC). Methods Spine clinic records from April 2005 to August 2011 were reviewed. The C1 SAC was measured on lateral radiographs, and the relative positions between a C1 posterior arch and the C3-C2 spinolaminar line were examined and considered "positive" when the C1 ring lay ventral to the line. Computed tomography (CT) scans and magnetic resonance imaging (MRI) were utilized to measure precise diameters of C1 and C2 SAC and to check the existence of spinal cord compression. Results Four hundred eighty-seven patients were included in this study. There were 246 men and 241 women, with an average age of 53 years (range: 18 to 86). The mean SAC at C1 on radiographs was 21.2 mm (range: 13.5 to 28.2). Twenty-one patients (4.3%) were positive for the spinolaminar line test; all of these patients had C1 SAC of 19.4 mm or less. Eight patients (1.6%) had C1 SAC smaller than C2 on CT examination; all of these patients had a positive spinolaminar test, with high sensitivity (100%) and specificity (97%). MRI analysis revealed that two of the eight patients with a smaller C1 SAC had spinal cord compression at the C1 level. Conclusion Although spinal cord compression at the level of atlas without instability is a rare condition, the spinolaminar line can be used as a screening of C1 stenosis.

Correlation of posterior occipitocervical angle and surgical outcomes for occipitocervical fusion

Study Type Retrospective cohort study.

Introduction Craniocervical instability is a surgical disease, most commonly due to rheumatoid arthritis, trauma, erosive pathologies such as tumors and infection, and advanced degeneration. Treatment involves stabilization of the craniovertebral junction by occipitocervical instrumentation and fusion. However, the impact of the fixed occipitocervical angle on surgical outcomes, in particular the need for revision surgery and the incidence of dysphagia, remains unknown. Occipitocervical fusions (OCFs) at a single institution were reviewed to evaluate the relationships between postoperative neck alignment, the need for revision surgery, and dysphagia.

Objective The objective of this study is to determine whether an increased posterior occipital cervical angle results in an increase in the need for revision surgery, and secondary, dysphagia.

Methods A retrospective review of spinal surgery patients from January 2007 to June 2013 was conducted searching for patients who underwent an occipitocervical instrumented fusion utilizing diagnostic and procedural codes. Specifically, a current procedural code of 22590 (arthrodesis, posterior technique [craniocervical]) was queried, as well those with a description of “craniocervical” or “occipitocervical” arthrodesis. Ideal neck alignment before rod placement was judged by the attending surgeon. A review of all cases for revision surgery or evidence of dysphagia was then conducted.

Results From January 2007 to June 2013, 107 patients were identified (31 male, 76 female, mean age 63). Rheumatoid arthritis causing myelopathy was the most common indication for OCF, followed by trauma. Twenty of the patients were lost to follow-up and seven died within the perioperative period. Average follow-up for the remaining 80 patients was 16.4 months. The mean posterior occipitocervical angle (POCA), defined as the angle formed by the intersection of a line drawn tangential to the posterior aspect of the occipital protuberance and a line determined by the posterior aspect of the facets of the third and fourth cervical vertebrae, calculated after stabilization, was 107.1 degrees (range, 72–140 degrees). Reoperation was required in 11 patients (11/107, 10.3%). The mean POCA for the reoperation group was 109.5 degrees (range, 72–123) and was not significantly different than patients not requiring reoperation (106.5, p > 0.05). However, for all pathologies excluding infection as a cause for reoperation, the mean POCA was significantly higher, 115.14 degrees (p = 0.039) (Table 1). Seven patients (6.5%) complained of dysphagia postoperatively with a significantly higher POCA of 115 degrees (p = 0.039). Of these seven patients, six underwent posterior-only procedures. One patient underwent anterior and posterior procedures for a severe kyphotic deformity. The dysphagia resolved in six patients over a mean of 3 weeks (range, 2–4 weeks). One patient, whose surgery was posterior only, required the insertion of a gastrostomy tube.

Conclusions An elevated POCA may result in need for reoperation due to increased biomechanical stress upon adjacent segments or the construct itself due to flexion in an attempt to maintain forward gaze. Further, an elevated POCA seems to also correlate with a higher incidence of dysphagia. Further investigation is necessary to determine the ideal craniocervical angle which is likely individualized to a particular patient based on global and regional spinal alignments.

Defining hyoplasia of the atlas: a cadaveric study

STUDY DESIGN

Cadaveric study.

OBJECTIVE

To define congenital hypoplasia of the atlas.

SUMMARY OF BACKGROUND DATA

Little has been written about hypoplasia of the atlas and it is usually described in the setting of other skeletal dysplasias or syndromes.

METHODS

A total of 543 cervical spine specimens were randomly selected from the Hamann-Todd collection. Sagittal and coronal diameters of the atlas, axis, and C3 (when available), and the dens diameter were measured using digital calipers. Correction for modern size and radiographical magnification was performed. Hypoplasia of the atlas was defined as the lowest 2.5% of measurements. The correlation between inner sagittal diameters at C1 and C3 was calculated.

RESULTS

The mean C1 inner sagittal diameter was 30.8 ± 2.4 mm (range, 23.5-38.1 mm). We defined C1 hypoplasia as an inner sagittal diameter value representing the smallest 2.5% of subjects. Because the mean was 30.8 mm, hypoplasia was defined as a diameter of ≤26.1 mm or less. Correcting for size and magnification of radiographs, hypoplasia is defined as an inner sagittal diameter of the atlas of 28.9 mm. Approximately 10% of cases had a dens that occupied more than 40% of the spinal canal at C1, thus not following Steel's Rule of Thirds. There was only a moderate correlation between the spinal canal diameter at C1 and at C3 (r = 0.483, N = 345; P < 0.001).

CONCLUSION

With an inner sagittal diameter of 26 mm or less, one may describe the atlas as hypoplastic. Ten percent of the specimens had an odontoid process that occupied more than 40% of the spinal canal at C1. There was little correlation between the inner sagittal diameter at C1 and the diameter at C3.

LEVEL OF EVIDENCE

N/A.

A review of the diagnosis and treatment of atlantoaxial dislocations

Study Design Literature review. Objective Atlantoaxial dislocation (AAD) is a rare and potentially fatal disturbance to the normal occipital-cervical anatomy that affects some populations disproportionately, which may cause permanent neurologic deficits or sagittal deformity if not treated in a timely and appropriate manner. Currently, there is a lack of consensus among surgeons on the best approach to diagnose, characterize, and treat this condition. The objective of this review is to provide a comprehensive review of the literature to identify timely and effective diagnostic techniques and treatment modalities of AAD. Methods This review examined all articles published concerning "atlantoaxial dislocation" or "atlantoaxial subluxation" on the PubMed database. We included 112 articles published between 1966 and 2014. Results Results of these studies are summarized primarily as defining AAD, the normal anatomy, etiology of dislocation, clinical presentation, diagnostic techniques, classification, and recommendations for timely treatment modalities. Conclusions The Wang Classification System provides a practical means to diagnose and treat AAD. However, future research is required to identify the most salient intervention component or combination of components that lead to the best outcomes.

Imaging of the craniovertebral junction anomalies in children

The craniovertebral junction (CVJ) is interposed between the unsegmented skull and the segmented spine; it is functionally unique as it allows the complex motion of the head. Because of its unique anatomy, numerous craniometric indices have been devised. Because of its complex embryology, different from that of the adjacent skull and spine, it is commonly the seat of malformations. Because of the mobility of the head, and its relative weight, the craniovertebral junction is vulnerable to trauma. Like the rest of the axial skeleton, it may be affected by many varieties of dysplasia. In addition, the bony craniovertebral junction contains the neural craniovertebral junction and its surrounding CSF: any bony instability or loss of the normal anatomic relationships may therefore compromise the neural axis. In addition, the obstruction of the meningeal spaces at this level can compromise the normal dynamics of the CSF and result in hydrocephalus and/or syringohydromyelia. To image the CVJ, plain X-rays are essentially useless. MR is optimal in depicting the soft tissues (including the neural axis) and the joints, as well as the bone itself. CT still may be important to better demonstrate the bony abnormalities.

Review of cervical spine anomalies in genetic syndromes

STUDY DESIGN

Focused review of the literature.

OBJECTIVE

Assist spine specialists in diagnosis and treatment of cervical spine anomalies found in selected genetic syndromes.

SUMMARY OF BACKGROUND DATA

Cervical spine instability and/or stenosis are potentially debilitating problems in many genetic syndromes. These problems can be overlooked among the other systemic issues more familiar to clinicians and radiologists evaluating these syndromes. It is imperative that spine specialists understand the relevant issues associated with these particular syndromes.

METHODS

The literature was reviewed for cervical spine issues in 10 specific syndromes. The information is presented in the following order: First, the identification and treatment of midcervical kyphosis in Larsen syndrome and diastrophic dysplasia (DD). Next, the upper cervical abnormalities seen in Down syndrome, 22q11.2 Deletion syndrome, pseudoachondroplasia, Morquio syndrome, Goldenhar syndrome, spondyloepiphyseal dysplasia congenita, and Kniest dysplasia. Finally, the chin-on-chest deformity of fibrodysplasia ossificans progressiva.

RESULTS

Midcervical kyphosis in patients with Larsen syndrome and DD needs to be evaluated and imaged often to track deformity progression. Upper cervical spine instability in Down syndrome is most commonly caused by ligamentous laxity at C1 to C2 and occiput-C1 levels. Nearly 100% of patients with 22q11.2 deletion syndrome have cervical spine abnormalities, but few are symptomatic. Patients with pseudoachondroplasia and Morquio syndrome have C1 to C2 instability related to odontoid dysplasia (hypoplasia and os odontoideum). Morquio patients also have soft tissue glycosaminoglycan deposits, which cause stenosis and lead to myelopathy. Severely affected patients with spondyloepiphyseal dysplasia congenita are at high risk of myelopathy because of atlantoaxial instability in addition to underlying stenosis. Kniest syndrome is associated with atlantoaxial instability. Cervical spine anomalies in Goldenhar syndrome are varied and can be severe. Fibrodysplasia ossificans progressiva features severe, deforming heterotopic ossification that can become life-threatening.

CONCLUSION

It is important to be vigilant in the diagnosis and treatment of cervical spine anomalies in patients with genetic syndromes.

Modified lightwand intubation in a child with spondyloepiphyseal dysplasia congenita

This is the case report on a 1-year 9-month-old boy suffering from spondyloepiphyseal dysplasia congenita who was successfully intubated with our modified lightwand intubation procedure for general anesthesia to undergo bilateral herniorrhaphy despite the great likelihood of facing a difficult airway because of unstable cervical spine. We bent the pediatric wand after it was encased in an endotracheal (ET) tube of appropriate diameter. The light tip of the wand was let to protrude just out of the bevel of the ET tube. Once the light bulb properly transilluminated the trachea, the ET tube was threaded gently into the trachea. The patient recovered from anesthesia smoothly and was discharged on the next day. This maneuver can facilitate both visual and tactile confirmations of the position and proper tube size. The effectiveness and safety of our modified lightwand intubation procedure is well demonstrated.

Neurosurgical management of congenital malformations and inherited disease of the spine

Congenital malformations encompass a diverse group of disorders present at birth as result of genetic abnormalities, infection, errors of morphogenesis, or abnormalities in the intrauterine environment. Congenital disorders affecting the brain and spinal cord are often diagnosed before delivery with the use of prenatal ultrasonography and maternal serum screening. Over the past several decades there have been major advances in the understanding and management of these conditions. This article focuses on the most common spinal congenital malformations.

A case report of a patient with cleft palate carrying the risk of tetraplegia

Spondyloepiphyseal dysplasia congenita (SEDC) is an inherited disorder of bone growth that results in short-trunk dwarfism, skeletal abnormalities, disorders in vision and hearing, atlanto-axial instability, and cleft palate. This important anomaly of the cervical vertebrae carries the risk of tetraplegia during cleft palate operations. In this case report, we discuss a case of spondyloepiphyseal dysplasia congenita, the perioperative and postoperative measures, and the risk of tetraplegia.

A systematic review of occipital cervical fusion: techniques and outcomes

Object

Numerous techniques have been historically used for occipitocervical fusion with varied results. The purpose of this study was to examine outcomes of various surgical techniques used in patients with various disease states to elucidate the most efficacious method of stabilization of the occipitocervical junction.

Methods

A literature search of peer-reviewed articles was performed using PubMed and CINAHL/Ovid. The key words “occipitocervical fusion,” “occipitocervical fixation,” “cervical instrumentation,” and “occipitocervical instrumentation” were used to search for relevant articles. Thirty-four studies were identified that met the search criteria. Within these studies, 799 adult patients who underwent posterior occipitocervical fusion were analyzed for radiographic and clinical outcomes including fusion rate, time to fusion, neurological outcomes, and the rate of adverse events.

Results

No articles stronger than Class IV were identified in the literature. Among the patients identified within the cited articles, the use of posterior screw/rod instrumentation constructs were associated with a lower rate of postoperative adverse events (33.33%) (p < 0.0001), lower rates of instrumentation failure (7.89%) (p < 0.0001), and improved neurological outcomes (81.58%) (p < 0.0001) when compared with posterior wiring/rod, screw/plate, and onlay in situ bone grafting techniques. The surgical technique associated with the highest fusion rate was posterior wiring and rods (95.9%) (p = 0.0484), which also demonstrated the shortest fusion time (p < 0.0064). Screw/rod techniques also had a high fusion rate, fusing in 93.02% of cases.

When comparing outcomes of surgical techniques depending on the disease status, inflammatory diseases had the lowest rate of instrumentation failure (0%) and the highest rate of neurological improvement (90.91%) following the use of screw/rod techniques. Occipitocervical fusion performed for the treatment of tumors by using screw/rod techniques had the lowest fusion rate (57.14%) (p = 0.0089). Traumatic causes of occipitocervical instability had the highest percentage of pain improvement with the use of screw/plates (100% improvement) (p < 0.0001).

Conclusions

Based on the existing literature, techniques that use screw/rod constructs in occipitocervical fusion are associated with very favorable outcomes in all categories assessed for all disease processes. For patients requiring occipitocervical arthrodesis for the treatment of inflammatory diseases, screw/rod constructs are associated with the most favorable outcomes, while posterior wiring and onlay in situ bone grafting is associated with the least favorable outcomes. Occipitocervical arthrodesis performed for the diagnosis of tumor is associated with the lowest rate of successful arthrodesis using screw/rod techniques, while posterior wiring and rods have the highest rate of arthrodesis. The nonspecified disease group had the lowest rate of surgical adverse events and the highest rate of neurological improvement.

Progressive atlanto-axial subluxation in Behcet's disease

Behcet's disease is a chronic inflammatory condition involving several organs, such as the skin, mucous membranes, eyes, joints, intestines, lungs and central nervous system. It rarely affects the spinal column. We describe a case of progressive atlanto-axial subluxation in a 44-year-old woman with Behcet's disease. The patient started complaining of posterior neck pain 10 years after the diagnosis of her Behcet's disease. Initial radiographs showed no abnormal finding, but follow-up radiographs 6 month later demonstrated atlanto-axial subluxation. To the best of our knowledge, this is the second reported case in the worldwide literature of an atlanto-axial instability in a patient with Behcet's disease.

The use of recombinant human BMP-2 as a salvage procedure in the pediatric spine: a report on 3 cases

The study is a retrospective case series. The objective is to review the results after off-label recombinant human BMP-2 (rhBMP-2) use in the pediatric spine after previously failed spinal fusion. Non-union in the pediatric spine is a challenging condition associated with increased morbidity due to instability, neurological impairment or multiple revision surgeries. BMP has been used with good results in the adult spine; however, information on its use in the pediatric population is still lacking. rhBMP-2 was used at our institution at revision posterior spinal surgery in three patients. Solid spinal fusion was achieved in all three cases despite underlying bone dysplasia (Hurler's disease), instability or bony substance loss. No adverse reactions due to rhBMP-2 use were observed. rhBMP-2 should be considered as potential option to achieve spinal fusion in children with compromised bone healing due to congenital, local or systemic conditions.

Specific entities affecting the craniocervical region: syndromes affecting the craniocervical junction

INTRODUCTION

The craniocervical junction is a vital component in understanding the function of the human central nervous system. It is the threshold for major pathways affecting both brain and spinal cord function, and these structures are intricately housed in a network of bone, ligaments, and soft tissues. Abnormal development of any of these components may lead to altered structure, and therefore, altered function in the central nervous system.

MATERIALS AND METHODS

We herein describe a set of genetic syndromes that commonly affect the craniovertebral junction and offer clinical examples from more than 6,000 patients who have been treated for these disorders.

DISCUSSION

The syndromes described include Chiari type I malformation, Conradi syndrome, Goldenhar syndrome, Klippel-Feil syndrome, Larsen syndrome, Morquio syndrome, Pierre-Robin syndrome, spondyloepiphyseal dysplasia congenital and Weaver syndrome. The genetic mechanisms responsible for these disorders may offer unique insight into the developmental pathways and patterning in the musculoskeletal and cranial systems and may, ultimately, guide future diagnosis and treatment.

Spinal disorders associated with skeletal dysplasias and syndromes

Skeletal dysplasias are a heterogeneous group of disorders in which there is abnormal cartilage and bone formation, growth, and remodeling. There are more than 200 described skeletal dysplasias. Skeletal dysplasias can affect the spine in various ways, with attendant neurosurgical implications for diagnosis and treatment. Craniocervical junction abnormalities, atlantoaxial subluxation, and kyphoscoliotic deformity are among the common spinal problems that are found in certain skeletal dysplasias.

[Traumatic atlanto-occipital dislocation as part of a complex cervical spine injury. Case report in a 12-year-old girl]

Traumatic atlanto-occipital dislocation (AOD) appears to be an unusual and almost universally fatal injury. Although AOD is the cause of death in about 10% of fatal cervical spine injuries an increasing number of reports document cases of survival following this injury. Improved pre-hospital and in-hospital emergency care according to ATLS guidelines that include early cervical spine stabilization, effective diagnosis because of improved imaging after trauma including whole body multislice CT followed by expeditious reposition and adequate immobilization are reasons for this phenomenon. We report the case of a 12-year-old girl surviving an AOD accompanied by a distraction injury C6/7 with unilateral fixed spinal luxation. After a primary attempt at closed reduction and external stabilization with a halo vest, the injury was treated by a navigated dorsal spondylodesis C0-C1 using the CerviFix rod system and open reposition of the remaining subluxation C6/7 with laminar hooks. The literature was reviewed for diagnostic possibilities, management and prognosis of AOD.