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PubMed2000

Retro-dental reactive lesions related to development of myelopathy in patients with atlantoaxial instability secondary to Os odontoideum.

STUDY DESIGN: A retrospective analysis of 13 patients with atlantoaxial instability secondary to Os odontoideum who underwent posterior atlantoaxial fusion. OBJECTIVE: To assess the relationships between the development of myelopathy and plain radiographic parameters in patients with atlantoaxial instability secondary to Os odontoideum and to determine whether the pathologic structures, which compress the spinal cord, are visualized using magnetic resonance imaging. SUMMARY OF BACKGROUND DATA: The development of myelopathy, which is the most serious complication associated with Os odontoideum, was thought to be related to either the degree of instability or direction of instability, or a decrease in the space available for the cord. However, such indirect radiographic parameters measured using plain radiographs cannot provide direct information concerning the causes of myelopathy in patients with atlantoaxial instability secondary to Os odontoideum. METHODS: Thirteen patients who underwent posterior atlantoaxial fusion for clinical symptoms due to Os odontoideum were classified into two groups depending on whether they had (n = 9) or did not have (n = 4) myelopathy. Four radiographic parameters were measured using flexion and extension lateral radiographs; the degree of instability, the direction of instability, and the space available for the cord in flexion and extension. MRI was performed on all patients in the myelopathy group. The radiologic and clinical data were compared for the two groups. RESULTS: There were no significant statistical differences in the degree of instability (6.83 vs. 7.38, P = 0.816), space available for the cord in flexion (6.94 vs. 7.13, P = 0.938), and space available for cord in extension (7.56 vs. 5.75, P = 0.434) between the two groups. There was a poor agreement between the direction of instability and the development of myelopathy (kappa = 0.268, P = 0.308). Magnetic resonance imaging did demonstrate, however, cord compression caused by retro-dental reactive lesions in the myelopathy; cystic masses were present in two patients; and fibrocartilaginous masses were present in seven. CONCLUSION: The current study suggests that the value of plain radiographic parameters should be reevaluated as a means of evaluating myelopathy in patients with atlantoaxial instability secondary to Os odontoideum, and that retro-dental reactive lesions should be considered as the potential cause of myelopathy.

Adult↗
PubMed2000

Pathomechanisms of failures of the odontoid.

STUDY DESIGN: A finite element investigation to determine the causal mechanisms that lead to odontoid fracture. OBJECTIVES: To elucidate which loading scenarios, including rotational moments, compression-tension, and lateral and anteroposterior shear, can result in Type I, Type II, and Type III odontoid failures. SUMMARY OF BACKGROUND DATA: There is considerable controversy about the major loading path that causes odontoid fractures. A review of the clinical and laboratory research literature did not provide a consensus on this issue. METHODS: A three-dimensional, nonlinear finite element model of the occipito-atlantoaxial (C0-C1-C2) complex was generated from human cadaveric data. Force loads were applied at the posterior margin of the occiput and were applied as lone entities or after the model was prepositioned in flexion, extension, or lateral-bending moments through applied rotation moments. Intraosseous stresses were reported to characterize the probability of fracture due to the applied loadings. RESULTS: The data indicate that hyperextension can lead to failure of the odontoid at its superior tip (Type I). Finite element model predictions also demonstrated the propensity of loads that induce axial rotation to create relatively high maximum von Mises stress in the Type II fracture region. Flexion prepositioning reduced the stress response of the odontoid. CONCLUSIONS: Force loading that puts the head in extension coupled with lateral shear or compression leads to Type I fractures, whereas axial rotation and lateral shear can produce Type II fractures. The model failed to elucidate causal mechanisms for Type III fractures. Flexion seems to provide a protective mechanism against force application that would otherwise cause a higher risk of odontoid failure.

Atlanto-Occipital Joint↗
PubMed2001

Acute respiratory compromise associated with flexed cervical traction after C2 fractures.

STUDY DESIGN: Acute respiratory compromise is occasionally observed in a subgroup of patients with upper spinal injuries involving the C2 vertebrae. A retrospective review was performed to identify fracture types and risk factors for early respiratory deterioration following injury to the upper cervical spine. OBJECTIVES: To examine the frequency of respiratory complications encountered following traction manipulation of specific upper cervical spinal injuries involving the C2 vertebrae. SUMMARY OF BACKGROUND DATA: Major complications related to cervical skeletal traction are uncommon. Respiratory compromise with occasional mortality has been observed. Risk factors for acute respiratory failure are unknown. METHODS: The medical records of 166 consecutive patients with fractures of the C2 vertebrae admitted between January 1994 and July 1998 to a regional spinal cord injury center were examined. Demographic data, injury subtype, fracture displacement, respiratory status, treatment method, and outcome at discharge were examined. Patients with comorbidities compromising respiratory function were excluded. RESULTS: One hundred fifty-five patients met the inclusion criteria of this study. Sixty-one patients had Type II odontoid fractures of which 53 were displaced (32 posteriorly and 21 anteriorly). In addition, there were 21 patients with Type III odontoid fractures, 33 with axis C2 body fractures, 32 with Hangman's fractures, and eight patients with an os odontoideum. Thirteen of 32 patients with posteriorly displaced odontoid fractures experienced acute respiratory compromise following reduction with cervical skeletal traction and immobilization, while only three of the remaining 123 patients had respiratory difficulties. Respiratory distress as a consequence of cervical spine fractures resulted in three deaths. Two of these patients had posteriorly displaced Type II odontoid fractures whose airway could not be emergently intubated. CONCLUSION: Frequent respiratory deterioration (40% of patients) during acute management of posteriorly displaced Type II odontoid fractures after reduction was observed. Physicians must be aware that cervical flexion in the treatment of posteriorly displaced odontoid fractures may significantly increase the risk of airway obstruction due to the presence of acute retropharyngeal swelling. This may be avoided with elective nasotracheal intubation in this upper cervical spine fracture subtype.

Acute Disease↗
PubMed2001

Foramen magnum syndrome secondary to calcium pyrophosphate crystal deposition in the transverse ligament of the atlas.

STUDY DESIGN: This report illustrates two rare cases of foramen magnum syndrome caused by a retro-odontoid mass in which calcium pyrophosphate dihydrate crystals were found. OBJECTIVES: To analyze the preoperative studies and the diagnostic criteria and to discuss the surgical treatment. The present cases will be compared with previous ones described in the literature. SUMMARY OF BACKGROUND DATA: Deposition of calcium pyrophosphate dihydrate crystals occurs into the fibrous and hyaline cartilage of the joints and intervertebral discs of the spine. Half of the patients known to have a chondrocalcinosis had asymptomatic calcification in the odontoid region. Ten patients were published in the literature as having a spinal cord syndrome secondary to calcium pyrophosphate dihydrate deposition in the odontoid region. METHODS: In both cases the preoperative studies were analyzed, and the retro-odontoid mass was resected and histologically examined. Both had an anterior transoral approach and have been followed for 1 year. RESULTS: According to the preoperative radiographs the diagnosis was suspected and confirmed histologically. Transoral approach was done with no need in either case for a posterior stabilization. CONCLUSIONS: Compression of the spinal cord by calcium pyrophosphate dihydrate deposition may occur. The preoperative diagnosis may be highly suspected after radiographic study and histologically confirmed. Transoral resection is the treatment of choice. Posterior stabilization should be considered only in cases of craniovertebral instability.

Aged↗
PubMed2001

Salvage of a malpositioned anterior odontoid screw.

STUDY DESIGN: Description of surgical technique with case correlation. OBJECTIVE: This article presents an alternative approach to anterior odontoid screw salvage in a patient with established nonunion. SUMMARY OF BACKGROUND DATA: Type II odontoid fractures are often treated surgically because of their risk of nonunion. Anterior odontoid screw fixation offers stable fixation without loss of atlantoaxial motion. Treatment failure may occur despite adequate screw placement but is more likely when fixation is inadequate. The traditional solution is a posterior fusion. In selected cases the surgeon may want to revise the anterior instrumentation with the hope of retaining as much C1-C2 motion as possible. METHODS: A 43-year-old man presented 16 months after Type II odontoid fracture treated by anterior odontoid screw fixation. He had neck pain, instability, and a pseudarthrosis confirmed on radiographs. The screw was excessively long, piercing the C3 vertebral body and providing inadequate fixation. To avoid posterior fusion, a modified anterior approach was used. An entry point was selected 10 mm lateral to the midline, along the anterior rim of the C2 vertebral body. A large-diameter lag screw was then passed to the tip of the fragment. An angled curette was introduced into the fracture gap through the interval between the odontoid and the C1 ring. Autogenous bone was packed into the gap and along the old screw tract. RESULTS: At the 2-year follow-up the patient had a solid union with no neck pain, no headaches, no radicular symptoms, and excellent range of motion. The approach is described. CONCLUSION: In properly selected patients an anterior revision approach can provide a better outcome than posterior cervical fusion. This modified approach allows placement of an adequate fixation screw in a vertebra damaged by previous screw failure.

Adult↗
PubMed2002

Combined odontoid and jefferson fracture in a child: a case report.

STUDY DESIGN: A case of combined odontoid and Jefferson fracture is reported. OBJECTIVE: To alert spine physicians to the rare combination of an odontoid and Jefferson fracture in a child. METHODS: A 5-year old boy presented with neck pain and torticollis after falling on his head from a four-wheeler that had rolled over. A computed tomography scan confirmed a combined odontoid and Jefferson fracture. RESULTS: The child was successfully treated nonsurgically with a hard cervical orthosis. At this writing, the child clinically is asymptomatic 2 years after the injury. DISCUSSION: The fall on to the head caused the body weight to be transmitted to the atlas. The resulting force vector produced the classic Jefferson fracture of the atlas. As the atlas fracture spread with continued compressive and axial forces, tension was exerted on the alar ligaments (check ligaments), leading to the avulsion fracture of the odontoid. CONCLUSIONS: This is only the second reported case of a child with a combined Jefferson and odontoid fracture. This diagnosis should be considered in the evaluation of a child with neck pain and torticollis from a fall on the top of the head.

Cervical Atlas↗
PubMed2002

Simultaneous fracture of every cervical vertebra: a case study.

STUDY DESIGN: The case of a 14-year-old boy who sustained simultaneous fractures of every cervical vertebra in a high-energy snowmobile accident is reported. OBJECTIVE: To describe a case of multiple cervical spine fractures and their management. SUMMARY OF BACKGROUND DATA: Injuries from all-terrain vehicles and off-road vehicles, including snowmobiles, are increasing in severity and frequency. The reported case illustrates a result of high-impact loading in which the driver struck his head after being thrown from a snowmobile at high speed. METHODS: The 14-year-old boy in the reported case fractured C1-C7, but had no neurologic sequelae. RESULTS: The fractures were treated with a halo vest after traction and reduction of the displaced odontoid fracture. All the fractures healed with no residual cervical instability. CONCLUSIONS: This case report is the first to describe a patient of any age who sustained simultaneous fractures of every cervical vertebra. Treatment with a halo vest was successful in protecting the cervical spine until healing was complete.

Accidents↗
PubMed2002

Biomechanical testing of posterior atlantoaxial fixation techniques.

STUDY DESIGN: An in vitro biomechanical study of C1-C2 posterior fusion techniques was conducted using a cadaveric model. OBJECTIVE: To investigate and compare the acute stability afforded by a novel rod-based construct that uses direct polyaxial screw fixation to C1 and C2 with contemporary transarticular screw and wire techniques. SUMMARY AND BACKGROUND DATA: Acute stability of the atlantoaxial complex is required to achieve bony consolidation. Various forms of posterior wiring were the first standardized procedures advocated to achieve C1-C2 fixation, but because of insufficient construct stability, these techniques have been coupled with transarticular screw fixation. Significant technical difficulties, however, including the possibility of neurovascular compromise during implantation are associated with transarticular screw placement. A novel technique that uses direct polyaxial screw fixation to C1 and C2 and bilateral longitudinal rods was developed recently. However, there are no published reports detailing the biomechanical characteristics of this new construct. METHODS: In this study, 10 fresh-frozen human cadaveric cervical spines with occiput (C0-C4) were used. Osteoligamentous specimens were tested in their intact condition after destabilization via odontoidectomy, and after two different Gallie wiring techniques. Each specimen was assigned to one of the two screw fixation groups. Five specimens were implanted with the polyaxial screw-rod construct and tested. The remaining five specimens were tested after application of bilateral C1-C2 transarticular screws with Gallie wiring (Magerl-Gallie technique). Pure-moment loading, up to 1.5 Nm in flexion and extension, right and left lateral bending and right and left axial rotation, was applied to the occiput, and relative intervertebral rotations were determined using stereophotogrammetry (motion analysis system). Range of motion data for all fixation scenarios were normalized to the destabilized case, and statistical analysis was performed using one-way analysis of variance with Fisher's least significant difference PLSD post hoc test for multiple comparisons. RESULTS: The data indicate that destabilization via odontoidectomy significantly increased C1-C2 motion. Both screw techniques significantly decreased motion, as compared with both Gallie wiring methods in lateral bending and axial rotation (P < 0.02 for all) and tended toward reduced motion in flexion-extension. There was no statistically significant difference between the two screw techniques. CONCLUSIONS: The results clearly indicate the screw-rod system's equivalence in reducing relative atlantoaxial motion in a severely destabilized upper cervical spine, as compared with the transarticular screw-wiring construct. These findings mirror the previously reported clinical results attained using this new screw-rod construct. Thus, the decision to use either screw construct should be based on safety considerations rather than acute stability.

Adult↗
PubMed2004

Accident-induced late complaint of odontoid nonunion.

STUDY DESIGN: A case of accident-induced late complaint of odontoid nonunion is reported. OBJECTIVES: To report a rare case of accident-induced late complaint of odontoid nonunion and to discuss operative techniques of stabilization. SUMMARY OF BACKGROUND DATA: The literature is reviewed. METHODS.: A 60-year-old man sustained a neck injury with incomplete transverse lesion after a traffic accident. A loosening of odontoid nonunion with displacement 40 years after primary trauma was noted. RESULTS: Surgical treatment of the odontoid nonunion was undertaken to perform anterior screw fixation and additional posterior C1-C2 arthrodesis according to Gallie or Brooks. The patient wore a cervical brace for 6 weeks and underwent physiotherapy. Neurologic deficit decreased after surgery. CONCLUSION: This is the first reported case of accident-induced loosening of odontoid nonunion. Anterior screw fixation and posterior C1-C2 arthrodesis achieved stable fixation.

Accidents, Traffic↗
PubMed2001

Dynamic intraoperative kinking of flexometallic tube.

A 22-year-old male patient had two episodes of oxygen desaturation with concomitant increase in end-tidal carbon dioxide and airway pressure while undergoing transoral odontoidectomy under fluoroscopy. Dynamic kinking of the flexometallic endotracheal tube from compression by a Dingman retractor was responsible. Fluoroscopic imaging was helpful in confirming the etiology of sudden alteration in the monitoring parameters.

Adult↗
PubMed2002

Toxic epidermal necrolysis after phenytoin usage in a brain trauma patient.

Toxic epidermal necrolysis is a drug-induced, rare, but life-threatening skin eruption. The main differential diagnoses are drug-induced erythema (hypersensitivity syndrome), acute graft-versus-host disease, staphylococcal scalded skin syndrome, and toxic shock syndrome. Because the therapy for toxic epidermal necrolysis and acute graft-versus-host disease differs largely from the others, it is necessary to make an accurate diagnosis. In addition to a detailed medical history, skin biopsy is mandatory because the skin eruptions are not always unequivocal. Discontinuation of the causing agent is crucial, and treatment in specialized intensive care units or burn units is supportive. Currently there is no specific treatment for toxic epidermal necrolysis. Advantages from corticosteroids, plasmapheresis, intravenous immunoglobulin, cyclophosphamide, cyclosporin, and N-acetylcysteine still remain to be established by controlled trials, or have failed to prove a benefit (thalidomide). The patient presented here demonstrates the difficulties in diagnosing toxic epidermal necrolysis in a critically ill patient. A short overview of the pathogenesis and the management of toxic epidermal necrolysis is provided.

Accidents, Traffic↗
PubMed2002

Combined anterior and posterior approach for managing basilar invagination associated with type I Chiari malformation.

Ventral brainstem compression is common in patients with basilar invagination associated with type I Chiari malformation. The aim of this study was to investigate the reliability of a combined one-session anterior-posterior surgical approach for these patients. Nine patients underwent transoral odontoidectomy, posterior foramen magnum decompression, occipitocervical fixation, and bone grafting. All but two patients had ventral and dorsal operations in one surgical sitting. One of these two individuals had previously undergone posterior decompressive surgery at another hospital, but his condition had deteriorated rapidly afterward. The mean follow-up time was 19 months (range, 14-30 months). There was no mortality and no significant morbidity in this series. All but one of the patients showed significant improvement in their symptoms. Chiari malformations have a surprisingly high association with basilar invagination, and patients may have symptoms in both conditions. If there is a marked anterior compression, anterior transoral and posterior decompression, fusion, and instrumentation is an optimal strategy for treating patients with basilar invagination associated with type I Chiari malformation.

Adolescent↗
PubMed2001

Indications of Philadelphia collar in the treatment of upper cervical injuries.

The principles of the management of upper cervical injuries remain controversial. The specific anatomical conditions render upper cervical injuries more problematic than lower cervical injuries. Here we present and discuss our experiences with upper cervical injury, comparing them with other treatment modalities. The 24 patients admitted to our department with upper cervical injury were treated surgically or conservatively according to their neurological and radiological status. Five patients were treated surgically due to neurological abnormality associated with compression to neural structures observed in computerized tomography/magnetic resonance imaging (CT/MRI). Patients with no neural compression were managed conservatively, with the Philadelphia collar. All patients showed stable fracture healing and experienced no additional clinical disability on follow-up after a minimum of 3 months, except one who died due to cardiac and respiratory failure. Regardless of the type of injury, indication for surgery in many cases of upper cervical injury is neurological abnormality associated with radiologically observed neural compression. It is our belief that, in the absence of both neurological abnormality and compression to neural structures observed in CT/MRI, treatment with the Philadelphia collar alone is safe, cost-effective and easily applicable for many cases of upper cervical injury.

Adult↗
PubMed2004

Surgical treatment for atlantoaxial subluxation with myelopathy in spondyloepiphyseal dysplasia congenita.

STUDY DESIGN: A retrospective review of 21 patients with spondyloepiphyseal dysplasia congenita (SEDC), including 7 operated patients for atlantoaxial subluxation. OBJECTIVES: To clarify the morphological findings of atlantoaxial subluxation in SEDC patients and to evaluate the operative procedures based on these image findings. SUMMARY AND BACKGROUND DATA: The presence of atlanto axial sublucation with hypoplasia of the odontoid and/or lax ligaments leads to myelopathy in patients with spondyloepiphyseal dysplasia congenita. METHODS: We retropectively reviewed the physical and morphological findings on atlantoaxial images and the clinical findings of myelopathy in 21 patients with SEDC. RESULTS: Myelopathy was found in 9 individuals with severe SEDC who presented with marked short stature and severe coxa vara; of these, 6 had gait disturbances. On the images of the 9 patients with myelopathy, the average sagittal canal diameter (SCD) at the level of the atlas was only 9.2 mm (range, 7-12 mm) with progressive atlantoaxial subluxation. The average atlantodental interval (ADI) was 3.5 mm (range, 2-6 mm) in the presence of a sagittal atlas diameter (SAD) of less than 27.1 mm (range, 22-36 mm). Surgery was performed for 6 of the patients with myelopathy. Since their SADs were small, and the average SCD, at 9.9 mm (8-14 mm), was narrow even at the position of extension (the position of reduction for atlantoaxial subluxation), C1 laminectomy was needed for all these patients, and occipital-cervical posterior fusion was performed. Stability was satisfactory in all cases and the operative outcome for myelopathy was excellent for 1 case, fine for 4, and fair for 2. CONCLUSION: A small SAD may limit the effectiveness of reducing atlantoaxial subluxation. Persistent narrowing of the SCD may require concomitant C1 laminectomy and occipital-cervical fusion.

Adolescent↗