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

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

Prevalence and clinical relevance of underlying pathological conditions in painful adolescent idiopathic scoliosis: a MRI-based study.

STUDY DESIGN: Cross-sectional comparative study. OBJECTIVES: Evaluate prevalence and clinical relevance of an underlying pathology in painful adolescent idiopathic scoliosis (AIS) patients after a non-diagnostic history, physical examination and spinal X-ray using Magnetic Resonance Image (MRI) as diagnostic tool. Discrepancies regarding indications of routine MRI screening in painful AIS patients are multifactorial. Few studies have investigated relationship and practical importance of painful AIS with an underlying pathology by MRI. METHOD: A total of 152-consecutive AIS patients complaining of back pain during a 36-month period were enrolled. All patients underwent whole-spine MRI after a non-diagnostic history, physical examination and spinal X-ray. Underlying pathologies were reported as neural and non-neural axis abnormalities based on MRI reports. Variables such as sex, age, constant or intermittent pain, night pain, back pain location (thoracic or lumbar pain), Cobb-angle and follow-up were evaluated as clinical markers to predict presence of underlying MRI pathologies. RESULTS: The presence of an underlying pathology was found by MRI in 54 painful AIS patients (35.5%). Isolated syringomyelia was the only neural axis abnormality found in 6 patients (3.9%). Non-neural axis abnormalities (31.6%) were composed by: 32 herniated nucleus pulposus, 5 vertebral disc desiccation, 4 ovarian cysts, 3 renal cysts, 2 sacral cysts, and 2 vertebral hemangiomas. There was no association with gender, age of presentation, initial coronal Cobb angle and follow up; with presence of an underlying pathology. Lumbar pain location was identified as an adequate clinical marker that correlated with presence of an underlying pathology (p = 0.01). CONCLUSIONS: Prevalence of underlying pathologies diagnosed by MRI in painful AIS was found high (35.5%), but it's clinical relevance and implication are debatable. The use of MRI did not affect orthopedic management of painful AIS patients who showed an underlying pathology. A thorough evaluation must be performed by clinicians; and discussed with patients and family prior to undergo further imaging management. LEVEL OF EVIDENCE: Level III.

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.

Auxiliary Wings of the Axis.

Bony anomaly of axis (C2) vertebra is well known. However, expansion of the posterior element is less documented. We describe a case of additional bony ring attached to the posterior spinous process in a 10-year-old male who presented with the complaint of progressive swelling at the upper cervical region. On physical examination a firm swelling approximately 8 × 5 cm was present at the back of the neck just below the hair line. There was no focal neurologic deficit. Computed tomography scan of the cervical spine showed an additional bony arch attached to the spinous process of the C2 vertebra. Magnetic resonance imaging revealed a soft tissue mass within the additional bony ring without involvement of neural structures. Complete surgical excision of the mass was done. Anomalous expansion of the spinous process of the C2 vertebra may remain silent. Surgery may be necessary for cosmetic purposes.

Anatomical variations of vertebral artery and C2 isthmus in atlanto-axial fusion: Consecutive surgical 100 cases.

VA anomalies in extra- and intraosseous regions of the craniovertebral junction (CVJ) is considered very carefully during the posterior screw fixation for the atlantoaxial instability (AAI). This study aims to compare the incidence and variations of VA anomalies, isthmus and pedicle size of C2 in 100 patients with AAI due to congenital skeletal anomaly (CSA) and acquired disease by using three-dimensional CT angiograms (3D CTA) before surgery. The CSA group contained 48 patients and the acquired disease group consisted of 52. In the CSA group, Os odontoideum was the major cause with 43 patients. The causes of acquired disease were RA in 16 patients and OA in 36 patients. Five patients had the anomalous VA in only CSA group; fenestration 2 patients and persistent first intersegmental (PFIS) artery 3 patients. Between CSA and acquired disease groups, no significant differences were found in the isthmus height, internal height, and pedicle width of C2 except the right internal height that is bigger in CSA group. The high-riding VA (isthmus height <4 mm or internal height <2 mm) had no significant difference between CSA group (27.1%) and acquired disease group (34.6%). However, in acquired disease group, patients with rheumatoid arthritis had smaller left internal height (4.21 ±â€¯1.63 vs. 5.51 ±â€¯1.83 mm) and pedicle width (4.11 ±â€¯1.05 vs. 5.05 ±â€¯1.66 mm) of C2 than those of patients with degenerative osteoarthritis. Therefore, in the case of atlantoaxial fusion, we should contemplate VA anomaly and the high-riding VA, especially in patients with CSA and RA.

C2 Translaminar Screw Fixation in Children.

BACKGROUND: Axis (C2) screw fixation has been shown to be effective in treating disorders that necessitate cervical stabilization. Although translaminar C2 screws have demonstrated clinical efficacy in adults, this technique has not yet been thoroughly investigated in children. This study describes the indications, technique, and results of translaminar C2 screw fixation in a case series of pediatric cervical spine disorders. METHODS: We searched the orthopaedic database at our institution for patients who had undergone a cervical spinal fusion that encompassed C2 between 2007 and 2017. Operative records were reviewed to determine if C2 screw fixation was performed and, if so, the type of C2 screw fixation. Clinical data with regard to patient age at surgery, diagnosis, procedure details, intraoperative complications, and postoperative complications were recorded. Preoperative and postoperative computer tomographic scans were reviewed to determine laminar measurements and containment, respectively. RESULTS: In total, 39 C2 translaminar screws were placed in 23 patients that met our inclusion criteria. The mean age was 12.6 years (range, 5.2 to 17.8 y) with a mean of 2 levels fused (range, 1 to 6). Diagnoses included 7 patients with instability related to skeletal dysplasia, 6 os odontoideum, 4 congenital deformities, 3 basilar invaginations, 2 cervical spine tumors, and 1 fracture. Indications for C2 translaminar screws included 14 cases with distorted anatomy favoring C2 translaminar screws, 6 cases without explicit reasoning for translaminar screw usage in the patient records, and 3 cases with intraoperative vertebral artery injury (1 sacrificed secondary to tumor load and 2 others injured during exposure because of anomalous anatomy). The vertebral artery injuries were not due to placement of any instrumentation. There were no screw-related intraoperative or postoperative complications and no neurological injuries. All patients demonstrated clinical union or healing on follow-up with no episodes of nonunion. CONCLUSIONS: Translaminar C2 screw fixation can be reliably used in the pediatric population. Our series contained no screw-related complications, no neurological injuries, and all patients demonstrated clinical union or healing. LEVEL OF EVIDENCE: Level IV-Case series.

Reduction of atlantoaxial dislocation prevented by pathological position of the transverse ligament in fixed, irreducible os odontoideum: operative illustrations and radiographic correlates in 41 patients.

OBJECTIVE Os odontoideum (OO) is a craniovertebral junction (CVJ) abnormality in which an ossicle (small bone) is cranial to a hypoplastic dens by a variable gap. This abnormality can result in instability, which may be reducible or irreducible. What leads to irreducibility in OO is unclear. Therefore, the authors sought to better understand the causes of irreducibility in OO. METHODS A retrospective review was conducted, which identified more than 200 patients who had undergone surgical treatment for OO between 1978 and 2015 at the University of Iowa Hospitals and Clinics. Only the 41 patients who had irreducible OO were included in this study. All inpatient and outpatient records were retrospectively reviewed, and patient demographics, clinical presentation, radiographic findings, surgical treatment, and operative findings were recorded and analyzed. RESULTS The cohort of 41 patients who were found to have irreducible OO included both children and adults. A majority of patients were adults (61% were 18 years or older). Clinical presentation included neck pain and headache in the majority of patients (93%). Weakness, sensory disturbances, and myelopathy were invariably present in all 41 patients (100%). Down syndrome was much more common in the pediatric cohort than in the adult cohort; of the 16 pediatric patients, 6 had Down syndrome (38%), and none of the adults did. Of the 16 pediatric patients, 5 had segmentation failure (31%) in the subaxial spine, and none of the adults did. A form of atlantoaxial dislocation was seen in all cases. On CT imaging, atlantoaxial facets were dislocated in all 41 cases but did not have osseous changes that would have prevented reduction. On MRI, the transverse ligament was identified anterior and inferior to the ossicle and superior to the hypoplastic odontoid process in all cases in which these studies were available (i.e., post-MRI era; 36 of 36 cases). The ligament was hypointense on T2-weighted images but also had an associated hyperintense signal on T2 images. Intraoperatively, the transverse ligament was identified anterior and inferior to the ossicle and superior to the hypoplastic odontoid process in all 41 cases. CONCLUSIONS In the largest series to date of irreducible OO and the only study to examine variable factors that lead to irreducibility in OO, the authors found that the position of the transverse ligament anterior and inferior to the ossicle is the most common factor in the irreducibility of OO. The presence of granulation tissue and of the dystopic variant of OO is also associated with irreducibility. The presence of Down syndrome and segmentation failure probably leads to faster progression of ligamentous incompetence and therefore earlier presentation of instability and irreducibility. This is the first study in which intraoperative findings regarding the transverse ligament have been correlated with MRI.

Cervical myelopathy caused by invaginated laminae of the axis associated with occipitalizaion of the atlas: Case report and literature review.

RATIONALE: In previous studies, few cases of cervical myelopathy caused by invaginated anomalous laminae of the axis have been reported, and none of them was combined with occipitalization of the atlas. PATIENT CONCERNS: A 28-year-old male was brought to our hospital with motor and sensory impairments of the extremities after a car accident. DIAGNOSES: MRI showed the spinal cord was markedly compressed at the C2/3 level. Reconstructed CT scans revealed an invaginated laminae of axis into the spinal canal as well as atlas assimilation. INTERVENTIONS: The patient was successfully managed with surgical treatment by removal of the anomalous osseous structure as well as fixation and fusion. OUTCOMES: The patient had a rapid recovery after the operation. He regained the normal strength of his 4 extremities and the numbness of his extremities disappeared. He returned to his normal work 3 months after the surgery without any symptoms. LESSONS: Invaginated laminae of axis combined with occipitalization of the atlas is a rare deformity. MRI and reconstructed CT scans are useful for both diagnosing and surgical planning of this case. Surgical removal of the laminae results in a satisfactory outcome. The pathogenesis of this anomaly could be the fusion sequence error of the 4 chondrification centers in the embryological term.

Cervical Spine Deformity in Long-Standing, Untreated Congenital Muscular Torticollis.

BACKGROUND: Congenital muscular torticollis (CMT) is a benign condition. With early diagnosis and appropriate management, it can be cured completely, leaving no residual deformity. However, long-standing, untreated CMT can lead to permanent craniofacial deformities and asymmetry. METHODS: Four adult patients presented to the author with long-standing, untreated CMT. Initial clinical assessment demonstrated tightness of the sternocleidomastoid muscle on the affected side. Investigation of cervical spine using 3-dimensional computed tomography scans with cervical segmentation allowed a 3-dimensional module to be separately created for each vertebra to detect any anatomical changes. RESULTS: A change in the axis of the vertebral column was noted when compared to that of the skull. Also, there were apparent anatomical changes affecting the vertebrae, which were most noticeable at the level of the atlas and axis vertebrae. These changes decreased gradually till reaching the seventh cervical vertebra, which appeared to be normal in all patients. The changes in the atlas vertebra were mostly due to its intimate relation with the skull base. The changes of the axis were the most significant, affecting mainly the superior articular facet, the lamina, and the body. CONCLUSIONS: There were seemingly permanent changes along the cervical spine region in the adult patients with long-standing, untreated CMT in the form of bending and rotation deformities that might result in residual torticollis postoperatively.

Cervical Myelopathy Caused by Bilateral Laminar Cleft of the Axis: Case Report and Review of Literature.

BACKGROUND: Cervical myelopathy due to bilateral laminar cleft of the axis is extremely rare, and few cases have been previously reported. However, its treatment is relatively simple. Surgical removal of the anomalous bony structure compromising the spinal canal can sufficiently achieve a good outcome. CASE DESCRIPTION: A 56-year-old man presented with a 2-year history of stiffness of the left upper and lower extremities. Cervical spine computed tomography showed a bony cleft at both laminae of the posterior arch of the axis, with obvious cord compression on magnetic resonance imaging. Although absence of right pedicle and spina bifida of C7 were also detected, there was no cord compression at this level. The patient underwent surgical removal of the anomalous laminar cleft and the spinous process of the axis. Postoperatively, he improved rapidly and was discharged on the seventh postoperative day. He was asymptomatic at the 3-year follow-up. After surgery, the preoperative myelopathy status was much improved. About 7 years after surgery, radiographs showed no kyphosis and instability. CONCLUSION: Invaginated bilateral laminar cleft of the axis is a rare cause of cervical myelopathy. The findings in our case should broaden the radiographic differential diagnosis in patients with cervical myelopathy. Surgical removal is an appropriate and simple treatment for this patient, resulting in a satisfactory outcome.

Results of the use of peek cages in the treatment of basilar invagination by Goel technique / Resultados do uso de cage em peek no tratamento da invaginação basilar pela técnica de Goel / Resultados de la utilización de caja de peek en el tratamiento de la invaginación basilar por la técnica de Goel

ABSTRACT Objective: Analysis of the use of polyetheretherketone (PEEK) cages for atlantoaxial facet realignment and distraction for treatment of basilar invagination by Goel technique. Method: Retrospective descriptive statistical analysis of the neurological status, pain, presence of subsidence and bone fusion with the use of PEEK cages in 8 atlantoaxial joints of 4 patients with basilar invagination. All patients were treated with atlantoaxial facet distraction and realignment and subsequent arthrodesis C1-C2 by the technique of Goel modified by the use of PEEK cage. Results: All patients showed improvement in Nurick neurological assessment scale and Visual Analogue Scale (VAS) of pain. There were no cases of subsidence, migration, or damage to the vertebral artery during the insertion of the cage. All joints evolved with bone fusion, assessed by dynamic radiographs, and computed tomography. Two patients developed neuropathic pain in dermatome of C2 and one patient had unilateral vertebral artery injury during C2 instrumentation treated with insertion of pedicle screw to control the bleeding. Conclusion: The results of the treatment of basilar invagination by the Goel technique with the use of PEEK cages shown to be effective and safe although further studies are needed to confirm this use.

RESUMO Objetivo: Análise do uso do implante tipo cage em poli-éter-éter-cetona (PEEK) no realinhamento e distração facetária atlantoaxial da invaginação basilar pela técnica de Goel. Método: Análise estatística descritiva retrospectiva de estado neurológico, dor, presença de fusão óssea e subsidência com o uso do cage em PEEK em 8 articulações atlantoaxiais de 4 pacientes portadores de invaginação basilar, todos tratados com distração, realinhamento atlantoaxial e artrodese posterior C1-C2 pela técnica de Goel, modificada pela utilização do cage em PEEK. Resultados: Todos os pacientes apresentaram melhora na escala de avaliação neurológica de Nurick e na Escala Visual Analógica (EVA) de dor. Não ocorreu caso de subsidência, migração ou dano à artéria vertebral decorrente da colocação do cage. Cem por cento das articulações evoluíram com fusão óssea, avaliada por radiografia dinâmica e tomografia computadorizada. Dois pacientes evoluíram com dor neuropática no dermátomo de C2 e em um paciente houve lesão unilateral da artéria vertebral durante a instrumentação de C2, tratada com inserção do parafuso pedicular para controle do sangramento. Conclusão: Os resultados da redução vertical da invaginação basilar pela técnica de Goel com a utilização de cage em PEEK mostrou ser eficaz e segura, porém ainda são necessários estudos para confirmar essa utilização.

RESUMEN Objetivo: Análisis del uso del implante tipo caja en poli-éter-éter-cetona (PEEK) en el realineamiento y distracción facetaria atlantoaxial de la invaginación basilar por la técnica de Goel. Métodos: Fue realizado un análisis estadístico descriptivo retrospectivo del status neurológico, dolor, presencia de fusión ósea y hundimiento con el uso de la caja en PEEK en 8 articulaciones atlantoaxiales de 4 pacientes que presentaban invaginación basilar, todos tratados con distracción y realineamiento atlantoaxial y artrodesis posterior C1-C2 mediante la técnica de Goel. Resultados: Todos los pacientes presentaron mejoría en la escala de evaluación neurológica de Nurick y en la Escala Visual Analógica (EVA) del dolor. No hubo casos de hundimiento, migración o daño a la arteria vertebral debido a la colocación del implante. El 100% de las articulaciones evolucionaron con fusión ósea evaluada por radiografía dinámica y tomografía computarizada. Dos pacientes evolucionaron con dolor neuropático en el dermatomo de C2, y en un paciente hubo lesión unilateral de la arteria vertebral durante la instrumentación de C2, tratada con inserción de un tornillo pedicular para control del sangrado. Conclusión: Los resultados de la reducción vertical de la invaginación basilar por la técnica de Goel con el uso de caja en PEEK han demostrado ser eficaz y segura pero se necesitan más estudios para confirmar este uso.

Atlantoaxial Instability.

Atlantoaxial instability is a congenital neurologic condition predominantly affecting toy breed dogs. Neurologic signs of a cranial cervical myelopathy typically present at a young age and can range from cervical pain (hyperesthesia) to paralysis. Diagnosis is often based on survey radiographs, although advanced diagnostic imaging can facilitate surgical planning, allow evaluation of spinal cord parenchyma, and rule out concurrent neurologic conditions. Treatment options consist of medical or surgical management, with surgical management being preferable in patients with neurologic deficits or those with unresolved cervical pain despite medical management. The prognosis for surgery is generally favorable.

Combined ossification of the posterior longitudinal ligament at C2-3 and invagination of the posterior axis resulting in myelopathy.

PURPOSE: Spinal stenosis at the C2-3 segment is a rare occurrence, and when it occurs myelopathy infrequently results. Furthermore, only a handful of cases involving congenital abnormalities of the posterior arch of the axis have been described resulting in cervical myelopathy many of which described simultaneous congenital abnormalities at adjacent levels and none of which identified ossification of the posterior longitudinal ligament (OPLL) at the same level. We report a case of a previously undescribed combination of abnormalities at the C2-3 segment resulting in clinical myelopathy. METHODS: A 49-year-old Chinese male presented with a progressive cervical myelopathy (C-JOA score 11 immediately pre-op). Segmental OPLL at the C2-3 disk space was visible, together with invagination of the bilaterally hypoplastic C2 lamina into the spinal canal. Signal abnormalities of the spinal cord were evident on both T1 and T2 sequences. RESULTS: The patient underwent a posterior decompression and instrumented fusion at C2-3 using pars screws at C2 and lateral mass screws at C3. Following surgery there was a rapid and significant improvement in the neurological symptoms, with the C-JOA score improving to 14 at final follow-up. A successful fusion was evident. CONCLUSIONS: Deficiencies in the posterior arch of the axis are rare and have not previously been reported in conjunction with OPLL. Advanced imaging is helpful to define the abnormality and site of compression. In the setting of a progressive neurological dysfunction, surgical decompression and stabilization is a reasonable intervention and can be associated with neurological and symptomatic improvement.

A cervical myelopathy caused by invaginated anomaly of laminae of the axis in spina bifida occulta with hypoplasia of the atlas: case report.

STUDY DESIGN: A case report and review of previous literature are presented. OBJECTIVE: The objective of this manuscript was to report a case of cervical myelopathy caused by invaginated anomalous laminae of the axis in a spina bifida occulta patient with hypoplasia of the arch of the atlas and to discuss the etiology of this disease. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, few cases of cervical myelopathy due to invaginated anomalous laminae of the axis have been reported, none of which is combined with hypoplasia of the arch of atlas. Treatment was surgical removal of the invaginated laminae. METHODS: The patient's history, clinical examination, imaging findings, and treatment were reported, and the etiology was discussed. RESULTS: Characteristic findings were revealed from imaging studies and multiplane reconstruction of the computed tomography images. The patient was treated with a posterior decompressive operation based on the images. A rapid improvement was observed after the surgery, and the patient's neurology was completely restored 1 month later. CONCLUSION: We reported a rare characteristic anomaly of the laminae of the axis with hypoplasia of the posterior arch of atlas. A multiplane reconstruction of the computed tomography images was very necessary for treatment of this case. Possible causes of this anomaly may be the failure of ossification or fusion of the embryological term, whereas invagination of the osteophyte may be associated with the traction of the dense fibrous band during growth and development. Surgical removal of the laminae could result in a satisfactory outcome.

Cervical myelopathy associated with congenital C2/3 canal stenosis and deficiencies of the posterior arch of the atlas and laminae of the axis: case report and review of the literature.

STUDY DESIGN: A case report of a young male suffering progressive neurologic dysfunction associated with a previously unreported combination of structural bony abnormalities. A review of the literature is also presented. OBJECTIVE: To describe a unique presentation of cervical myelopathy related to posterior deficiencies of the atlas and axis, and to report on the successful management of this case. SUMMARY OF BACKGROUND DATA: Cervical myelopathy from congenital canal stenosis is an uncommon presentation in the adolescent age group, especially affecting the C2/3 level. Aplasia of the atlas is a rare, although well-reported phenomena. Defects of the posterior elements of the axis are similarly uncommon. A combination of the 2 defects in the 1 patient has not previously been recorded. METHODS: A 14-year-old Caucasian male with no history of trauma or neck pain presented with progressive cervical myelopathy over a 2-year period. Plain radiograph and computed tomography revealed congenital aplasia of the posterior arch of the atlas and bilateral cleft defects of the laminae of the axis resulting in a free floating C2 spinous process. Magnetic resonance imaging showed T1 and T2 signal abnormality at the C2-C3 level, with C2/3 congenital canal stenosis and mild disc protrusion. RESULTS: The patient underwent a posterior decompression and lateral mass fixation at the C2/3 articulation to preserve maximal motion segments. At 12-month follow-up, the patient's cervical myelopathy had improved in terms of gait dysfunction and hemiparesis. Fusion was evident across the posterior lateral mass on radiologic investigation. CONCLUSION: Posterior deficiencies of the atlas and axis are rare occurrences in isolation, let alone in the 1 patient. This report broadens the radiographic differential diagnosis of patients presenting with cervical myelopathy, which has been associated with congenital posterior C2 anomalies in only a handful of patients. Surgery is an appropriate option for these patients faced with progressive neurologic dysfunction.

Cervical fixation in the pediatric patient: our experience.

The surgical management of cervical instability in children is a challenging issue. Although the indications for internal fixation are similar to those for adults, accurate pre-surgery study and sharp surgical techniques are necessary because of the size of such patients' anatomy, their peculiar tissue biology and the wide spectrum of diseases requiring cervical fusion. Our case study is made up of 31 patients, 15 male and 16 female, with an average age of 7 years and 6 months (2 years and 6 months to 18 years) who underwent cervical fusion for instability. Their physical condition presented various different pathologies ranging from congenital deformity, systemic skeletal disease, tumors, trauma, post-surgery instability. We performed occipito-cervical fusion in 11 cases, 5 of which involved stabilization at the cranium-vertebral junction. We used instrumentation in 13 cases (3 sublaminar wiring, 10 rigid adult instrumentation). We used rigid adult instrumentation in three patients under 10 years of age, treated by rod, occipital screws and sublaminar hook instrumentation in steel C0-C2 (9-year-old male, affected by os odontoideum in Down's syndrome; male of 7 years and 10 months, affected by os odontoideum in Down's syndrome; female of 4 years and 6 months with occipito-cervical stenosis and C0-C2 instability in Hurler's syndrome). We operated on two patients under 3 years of age, using sublaminar wiring with bone precursors and allograft at level C0-C2 (one of these was a 30-month-old male with post-traumatic instability C0-C2, while the other was a 17-month-old male with C0-C2 instability in Larsen's syndrome). The average follow-up age was 7 years and 1 month (between 1 and 18 years). Cervical fusion was assessed by X-ray examinations at 4th and 12th weeks and at 6th and 12th months after surgery. Where implants could allow, RMN examination was performed at 1st month after surgery. In the other cases, in which implants do not allow RMN to be performed, CT scan and standard X-rays were carried out, and new X-rays were performed every other year. We experienced two cases of sublaminar wiring rupture without impairment of bone fusion. No patient suffered major complications (infection and osteomyelitis, rigid instrumentation mobilization, incomplete fusion with instability, neurologic impairment, insufficient cervical spine range of movement to cope with everyday life activities, cervical pain). Even though most authors still indicate that rigid instrumentation should be performed in cases over 10 years of age and sublaminar wiring in cases over 3 years of age, our findings demonstrate that this age limit can be lowered. We have treated children under 10 years of age by rigid adult instrumentation and under 36 months of age by wiring. The anatomic size of the patient is the most important factor in determining the use of instrument arthrodesis to treat pediatric cervical spine instability. Although not easy, it is possible and preferable in many cases to adapt fixation to child cervical spine even in very young patients.

Treatment of pediatric atlantoaxial instability with traditional and modified Goel-Harms fusion constructs.

There are several treatment options for rigid fixation at C1-C2 including Brooks and Gallie type wired fusions and C1-2 transarticular screws. The use of a Goel-Harms type fusion, a construct with C1 lateral mass screws and C2 pedicle screws, has not been extensively described in pediatric patients. Here, we describe its relatively safe and effective use for treating pediatric patients by retrospective chart review of patients treated by the senior author for atlantoaxial instability with a Goel-Harms-type constructs during a 3-year period (2005-2007). Six patients were treated using Goel-Harms-type constructs. Five patients were treated utilizing a construct containing C1 lateral mass screws and C2 pedicle screws; one patient was treated using construct containing C1 lateral mass screws and C2 trans-laminar screws. The patients ranged in age from 7 to 17 years old (mean 12.7). All patients had findings of an os odontoideum on CT scans and three of the six patients had T2 hyperintensity on MRI. Three of the six patients presented with transient neurologic deficits: quadraplegia in two patients and paresthesias in two patients. In each patient C1 lateral mass and C2 screws were placed and the subluxation was reduced to attain an anatomical alignment. No bone grafts were harvested from the iliac crest or rib. Local morsalized bone and sub-occipital skull graft was used. All patients tolerated the procedure well and were discharged home on post-operative day 3-4. The patients wore a hard cervical collar and no halo-vests were needed. All patients had solid fusion constructs and normal alignment on post-operative imaging studies performed on average 14 months post-operatively (range: 7-29). The results demonstrated that Goel-Harms fusions are a relatively safe and effective method of treating pediatric patients with atlantoaxial instability and are not dependent on vertebral anatomy or an intact ring of C1. Follow-up visits and studies in this limited series of patients demonstrated solid fusion constructs and anatomical alignment in all patients treated.

Repair of Chiari III malformation using cranioplasty and an occipital rotation flap: technical note and review of literature.

BACKGROUND: Chiari III malformation (CM3) is rare among Chiari malformations (I-IV). Its definition has been expanded to include caudal medullary displacement and hindbrain herniation into encephaloceles in lower occipital and high cervical regions. Prognosis is recorded as dismal, with respect to survival and functional outcome. METHODS: We describe the presentation, radiologic evaluation, and repair of this malformation using methyl-methacrylate cranioplasty and an occipital scalp rotation flap for closure. Outcome after surgery is addressed. RESULTS: Adequate closure of the defect and protection of underlying structures was achieved without undue stress at incision site. CONCLUSIONS: This method of closure can be considered in cases of large occipital and cervical encephaloceles with poor skin cover and added osseous anomalies around the foramen magnum.

Vertical atlantoaxial index: a new craniovertebral radiographic index.

STUDY DESIGN: An index for measuring the vertical relationship of atlas and axis is described. OBJECTIVE: Deduction and application of vertical atlantoaxial index (VAAI) for quantifying the vertical atlantoaxial relationship of atlas and axis and classifying basilar invagination (BI) based on the VAAI. SUMMARY OF BACKGROUND DATA: A number of craniospinal parameters have been described to quantify the amount of BI in relation to herniation of odontoid into the cranium. Successful treatment of BI by distraction of atlantoaxial facet joint, placement of a spacer to maintain the distraction, and lateral mass fixation has been described recently. The treatment is based on the understanding that BI is in fact a disease of the atlantoaxial facet joints and is a result of progressive vertical instability. With this new concept and technique that involves preserving all bony elements and reduction of BI in the form of reducing the vertical atlantoaxial subluxation, we thought it was prudent to formulate an index to quantify the relation of atlas and axis in the sagittal plane. METHOD: Mid-sagittal computerized tomography (CT) scan films of 90 cases of BI treated by us between October 1999 and May 2005 with distraction and lateral mass plate and screw fixation were analyzed before and after surgery. The age of the patients ranged from 8 to 55 years and the male:female ratio was 2.5:1. Additionally, mid-sagittal CT scan films of hundred normal subjects in the same age group were analyzed as a control group. The VAAI was measured in all cases. VAAI is an index that measures the vertical relationship of the atlas and axis. The images were compiled and copies of the compilation were made. Two observers independently performed the measurements and intraobserver as well as interobserver agreement was assessed using the intraclass corelation (ICC) ) test (SigmaStat). RESULTS: The preoperative mean and mode values of VAAI in this series of patients were 0.53 (0.20 to 0.67) and 0.61, respectively. The postoperative mean and mode values of VAAI are 0.78 (range, 0.60 to 0.89) and 0.80, respectively. The mean and mode values of VAAI in general population were 0.80 (range, 0.76 to 0.85) and 0.80, respectively. The results in preoperative patients with BI demonstrated excellent intraobserver (ICC=0.96 and 0.98) and interobserver corelation coefficient (ICC=0.96). The results in normal subjects and postoperative CT scans of operated patients with BI also showed excellent intraobserver (ICC=0.97 and 0.98) and interobserver corelation coefficient (ICC=0.97). CONCLUSIONS: VAAI can be an excellent measurement tool for the assessment of relationship of atlas and axis. Nonrheumatoid BI can be graded and classified depending on the value of VAAI.

Symptomatic anomalies and arthrotic formations of the axis vertebrae in eastern Anatolian people. A local investigation

At the craniocervical junction, developmental anomalies of the axis may produce clinical symptoms by compressing the upper cervical cord during movements of the head and neck. The present study aimed at investigating several varieties and deformities of the axis on skeletal specimens of Eastern Anatolian origin. On 76 specimens, developmental anomalies and the variants of the second vertebrae (axis) were investigated. Hypoplasia of the dens axis in one specimen, the dens axis of a child with a bifid apex in another specimen and an arthrotic formation located on the apex of the dens in six axes were found. A bone protrusion narrowing the transverse foramen was also observed. The types of absence of the dens axis and clinical symptoms that may be caused by them are discussed. It was concluded that the frequency of arthrotic formations might reflect the possibility that the individuals suffered less commonly from neck pain due to arthrotic degeneration