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At least 595 records · Page 33Linked to original sources
PubMed2003

Anterior occiput-to-axis screw fixation: part I: a case report, description of a new technique, and anatomical feasibility analysis.

STUDY DESIGN: A case report of anterior screw fixation from the axis to the occiput is described, as is the surgical technique. The pertinent anatomy is described with a radiographic assessment of the feasibility, safety, and general applicability of this technique. OBJECTIVES: To describe a novel technique of anterior occipitocervical fixation and the pertinent anatomy. SUMMARY OF BACKGROUND DATA: In unique clinical situations where posterior fixation techniques may not be possible or may have already failed, an anterior screw fixation technique may add stability to further attempts at obtaining a posterior arthrodesis. METHODS: A case report is presented, followed by a detailed description of the surgical technique. Ten normal cervical spines had radiographs and computed tomography scans with reformats reviewed to determine screw entry points, target points, and proposed screw trajectories. Following screw insertion in eight fresh frozen human cadaver spine specimens, dissection verified screw location relative to structures at risk. RESULTS: The ideal entry point is located caudal to the C2 superior facet joint in line with the medial third of the C2 superior facet. The screw is directed 25 degrees posteriorly in the sagittal plane and 15 degrees laterally in the coronal plane. The screw tip is located in the posterolateral third of the occipital condyle. Anatomic variation is considerable and makes this technique inadvisable in up to 20% of cases. Structures at risk include the vertebral artery and the hypoglossal nerve. CONCLUSIONS: This new technique of anterior fixation of the atlas to the occiput is feasible and safe if meticulous surgical planning is performed.

Accidents, Traffic↗
PubMed2004

A cervical myelopathy due to invaginated laminae of the axis into the spinal canal.

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 due to anomalous laminae of the axis in a patient with spina bifida. SUMMARY OF BACKGROUND DATA: In previous studies, few cases of invaginated anomalous laminae of the axis have been reported. Treatment was surgical removal of the invaginated laminae. METHODS: The patient's history, clinical examination, imaging findings, and treatment were reported. RESULTS: Characteristic findings were revealed from imaging studies, a multiplane reconstruction of the CT images, and a stereolithographic model of the cervical spine. The patient was treated with a posterior decompressive operation. The outcome was satisfactory, with an improvement in the patient's neurology. CONCLUSIONS: This is a report of a rare characteristic anomaly of the laminae of the axis. A multiplane reconstruction of the CT images and a stereolithographic model were useful for treatment of this case. Possible causes of this anomaly may be the failure of ossification or fusion of the embryological term.

Axis, Cervical Vertebra↗
PubMed2004

An anatomic and morphometric study of C2 nerve root ganglion and its corresponding foramen.

STUDY DESIGN: Exposing and measuring the dorsal root ganglion of the second cervical spinal nerve (C2 ganglion) and the second intervertebral space, which is present between posterior arch of atlas (APA) and lamina of axis (LA). OBJECTIVES: This study aims to investigate the shape, size, and relation of the C2 ganglion with the adjacent structures that limits the corresponding intervertebral space and the alterations of relation between C2 ganglion and APA and between C2 ganglion and LA with the movements of the head bilaterally. SUMMARY OF BACKGROUND DATA: In previous studies, the position and the heights of the C2 ganglion have been described. But the shape of the C2 ganglion and its relation to APA and LA by the movement of the head had not been considered previously. METHODS: Upper cervical spines of 20 cadavers were dissected posteriorly. The muscles attaching to the atlas and axis were resected to ease the head movements. The heights of the C2 ganglion and space were measured in anatomic position and in hyperextension with opposite rotation position of the head. Originally in this study, plastic dough casts were used to obtain reliable outcomes. RESULTS: The shape of the ganglions was defined in three types: 70% were oval, 20% were spindle-like, and 10% were spherical. The height of the C2 ganglion was 4.97 +/- 0.92 mm on the right side and 4.6 +/- 0.84 mm on the left side. The height of the intervertebral space in anatomic position and in hyperextension with rotation to the opposite position of the head were, respectively, 9.74 +/- 1.77 mm and 7.48 +/- 1.44 mm on the right side and 9.64 +/- 1.47 mm and 7.12 +/- 0.96 mm on the left side. There was no bone contact or impact to the ganglion in each position of the head. CONCLUSION: The C2 ganglions are confident in their place between APA and LA. No bone contact to the C2 ganglion was detected in either normal limited or in forced head motions.

Adult↗
PubMed2004

Posterior screw placement on the lateral mass of atlas: an anatomic study.

STUDY DESIGN: An anatomic study evaluating the feasibility of posterior screw fixation on the lateral mass of the atlas and comparing the pullout force of C1 posterior lateral mass screws with that of occipital and C2 pedicle screws. OBJECTIVES: To study the feasibility, anatomy, and biomechanics of posterior screw fixation within the lateral mass of the atlas. SUMMARY OF BACKGROUND DATA: Occipitocervical fusion is a common choice for atlantoaxial dislocations. After that the movement of occipitocervical region will be restricted. If screws could be placed in the lateral mass of the atlas, 1) the movement of C0-C1 junction will be preserved; 2) through the screw the dislocated atlas could be pulled backward; and 3) the fractured lateral mass can be fixed using the posterior lateral mass screw directly. METHODS: Thirty atlas specimens of native adults were used to measure pertinent clinical data. Six fresh upper cervical specimens were used to observe the association of the C2 nerve and the lateral mass of the atlas. The pullout force of the C1 lateral mass was measured and compared with that of screws placed into the occiput and C2 pedicle, respectively. RESULTS: The distances from the midline to the midpoint of the C1 lateral mass, to the inner wall of the transverse foramen, and to the inner edge of the pedicle were 17.6 +/- 1.2 mm, 23.0 +/- 1.7 mm, and 14.2 +/-1.1 mm, respectively. The width and height of the C1 lateral mass were 11.6 +/- 1.4 mm and 12.7 +/- 1.0 mm, respectively. The distance between the inferior midpoint of the C1 lateral mass in the transverse plane of the midposterior arch of the atlas to the edge of the inferior atlas joint line was 4.1 +/- 0.7 mm. The width of the posterior arch at the point of vertebral artery overpass was 4.7 +/- 1.0 mm. The observation on the fresh specimens showed that the C2 nerve passes inferolateral to the C1-C2 joint and could be pulled sideways. The screw pullout force within the lateral mass of the atlas was 1818.16 +/- 422.67 N. This is significantly less than that of screws within the occiput, and there was no difference with that of a C2 pedicle screw. CONCLUSION: The width and height of the atlas lateral mass were larger than that of the C2 pedicle, and there was enough space to insert a 3.5-mm diameter screw in the atlas lateral mass over the C2 nerve. The pullout force of the screw on the lateral mass of the atlas was the same as that of the C2 pedicle screw. It is possible toinsert a 3.5-mm screw in the lateral mass of the atlas. The direction of the screw should be about 20 degrees anterosuperior in the vertical plane and 15 degrees inward in the horizontal plane. The suitable length of the screw should be approximately 22 mm inside the lateral mass.

Anthropometry↗
PubMed2005

Chance-type fractures of the axis.

STUDY DESIGN: A retrospective study was performed to identify horizontal fractures of the body of the axis, with special attention to their pattern, prevalence, and clinical outcome. OBJECTIVE: The prevalence of this type of injury and the long-term clinical behavior are examined. SUMMARY OF BACKGROUND DATA: Although isolated cases have been reported, horizontal Chance-type fractures of the body of the axis are not common cervical spine injuries. METHODS: The medical records of 674 consecutive patients with fractures of the cervical spine admitted to the authors' institute from 1970 to 2002 were reviewed. Of them, 2 (0.3%) had a horizontal Chance-type fracture of the body of the axis. Neurologic deficits were not diagnosed at admission. Mechanism of injury, treatment, and long-term follow-up were evaluated. RESULTS: Both patients were treated nonoperatively. At the latest follow-up, 3 and 12 years, respectively, both patients had a satisfactory clinical outcome. CONCLUSION: Horizontal fractures of the Chance-type of the body of the axis are rare. Conservative treatment proved to be effective.

Aged↗
PubMed2006

Comparison of the anatomical risk for vertebral artery injury associated with the C2-pedicle screw and atlantoaxial transarticular screw.

STUDY DESIGN: We evaluated the trajectories of atlantoaxial transarticular and C2-pedicle screws in 3 dimensions using computerized tomography. OBJECTIVE: To compare the anatomic risk for vertebral artery injury associated with C2-pedicle and atlantoaxial transarticular screws. SUMMARY OF BACKGROUND DATA: The atlantoaxial fixation technique using C1-lateral mass screws combined with C2-pedicle screws is considered a safer technique for preventing vertebral artery injury than atlantoaxial transarticular fixation. However, few reports have compared the anatomic risk of vertebral artery injury associated with C2-pedicle screws with that of transarticular screws. METHODS: A total of 62 consecutive patients with cervical lesions were evaluated using 3-dimensional images reconstructed by a computer-assisted navigation system. We compared the maximum possible diameters of the atlantoaxial transarticular screw and C2-pedicle screw trajectories, and examined whether the maximum possible diameters were limited by the height or width of the bony structure in screw trajectories < or = 4 mm in diameter. RESULTS: Mean maximum possible diameters did not differ significantly between the trajectories of 124 atlantoaxial transarticular and 124 C2-pedicle screws. In screw trajectories < or = 4 mm in diameter, 57.1% of transarticular screw trajectories were limited by the height of the bony structure, and all pedicle screw trajectories were limited by the width. CONCLUSIONS: C2-pedicle screw placement has nearly the same anatomic risk of vertebral artery injury as transarticular screw placement. Preoperative 3-dimensional evaluation may be useful for choosing the best surgical technique.

Adult↗
PubMed2006

Transoral vertebroplasty for renal cell metastasis involving the axis: case report.

STUDY DESIGN: Case report. OBJECTIVE: This is one of the first reported cases of transoral vertebroplasty for a solid metastatic tumor at C2 body. SUMMARY OF BACKGROUND DATA: Percutaneous vertebroplasty has gained popularity as a treatment option for painful neoplastic lesions of the spine. The technique has been useful in reducing pain and stabilizing the spinal segment that is vulnerable to fracture. However, there is very little experience with vertebroplasty in the cervical spine and, more specifically, at C2. METHODS: We present a case of metastatic renal cell carcinoma of the C2 body. The patient, a 61-year-old woman, presented with an excruciating neck pain. Diagnostic workup revealed the presence of tumor in the right kidney. Multiple spinal levels were involved in addition to C2, and the C2 lesion was treated for palliative purpose. Under biplanar fluoroscopy, a vertebroplasty trocar was placed transorally into the central portion of the C2 body, and polymethyl methacrylate was injected. RESULTS: The transoral vertebroplasty achieved complete pain relief and enhanced stability of an extensive osteolytic lesion involving the C2 body. CONCLUSIONS: This minimal access procedure was effective in completely relieving pain from a metastatic deposit at C2, while adequately stabilizing the vulnerable segment by the injection of polymethyl methacrylate. The transoral route requires meticulous fluoroscopic control to prevent the leakage of polymethyl methacrylate but provides the most direct access to the C2 body.

Axis, Cervical Vertebra↗
PubMed2007

Hangman's fracture: a biomechanical comparison of stabilization techniques.

STUDY DESIGN: In vitro biomechanical flexibility experiment studying 5 sequential conditions. OBJECTIVE: To determine the biomechanical differences among 3 fixation techniques after a simulated hangman's fracture. SUMMARY OF BACKGROUND DATA: Type II hangman's fractures are often treated surgically with a C2-C3 anterior cervical discectomy, fusion, and plating. Other techniques include direct fixation with C2 pars interarticularis screws or posterior C2-C3 fixation connecting C2 pars screws to C3 lateral mass screws. METHODS: Seven cadaveric specimens (Oc-C4) were tested intact, after a simulated hangman's fracture, and after each fixation technique. Flexion, extension, lateral bending, and axial rotation were induced using nonconstraining torques while recording angular motions stereophotogrammetrically. RESULTS: Direct screw fixation reduced motion an average of 61% +/- 13% during lateral bending and axial rotation compared to the injured state (P < 0.007). However, instability remained during flexion and extension. Posterior C2-C3 rod fixation provided significantly greater rigidity than anterior plate fixation during lateral bending (P < 0.008) and axial rotation (P < 0.04). CONCLUSIONS: Direct fixation of the pars ineffectively limits flexion and extension after a Type II hangman's fracture. If pars screw fixation can be achieved, posterior C2-C3 fixation more effectively stabilizes a hangman's fracture than anterior cervical plating.

Adult↗
PubMed2004

Cervical angina caused by atlantoaxial instability.

Cervical angina is defined as a paroxysmal precordialgia that resembles true cardiac angina caused by cervical spondylosis. Cervical angina most commonly results from compression of the C7 ventral root. We present here a case of cervical angina caused by atlantoaxial instability. This case had marked atlantoaxial instability but no flexibility of the middle to lower levels of the cervical spine. Although there was mild C7 root compression on the radiologic findings, the chest pain was induced by neck motion, and the precordialgia disappeared after posterior atlantoaxial fusion without C7 root decompression. Therefore, we diagnosed this case as cervical angina caused by spinal cord compression at the C1-C2 level. It was speculated that a perturbation of the sympathetic nervous system or a hypofunction of the pain suppression pathway in the posterior horn of the spinal cord caused the pectoralgia. Although cervical angina is a rare disease, physicians should be aware of it; if there are no abnormal findings on cardiac examinations for angina pectoris, they should examine the cervical spine. Cervical angina due to atlantoaxial instability is one of the differential diagnoses of precordialgia.

Afferent Pathways↗
PubMed2005

Tectorial membrane injuries in children.

We report three cases of tectorial membrane injury in children. An increased interspinous ratio was identified on cervical spine radiographs. The tectorial membrane injuries were diagnosed by magnetic resonance imaging. The three children were restrained passengers in high-speed motor vehicle accidents, and all sustained polytrauma. Two children with partial tears of the tectorial membrane were immobilized in a halo, and one with a longitudinal tear of the tectorial membrane had an occiput-to-C2 fusion.

Accidents, Traffic↗
PubMed2005

Atlantoaxial transarticular screw fixation and posterior fusion using ultra-high-molecular-weight polyethylene cable.

This article attempts to evaluate the effectiveness of the ultra-high-molecular-weight polyethylene (UHMW-PE) cable system in atlantoaxial transarticular screw fixation and posterior fusion through the clinical results of 10 postoperative patients with atlantoaxial subluxation secondary to rheumatoid arthritis. Among them, one patient with only one screw placed owing to an anomalous vertebral artery had the correction loss of the 3-mm atlas-dens interval after surgery. Another patient had a second operation to remove the screw and cable after 2 years 11 months because a unilateral transarticular screw had come to protrude through the lateral mass of the atlas ventrally. All patients had achieved C1-C2 osseous fusion without any complications associated with this cable system. The UHMW-PE cable is a very useful material as sublaminar wiring in atlantoaxial transarticular screw fixation and posterior fusion.

Aged↗
PubMed2005

Frameless stereotactic image-guided C1-C2 transarticular screw fixation for atlantoaxial instability: review of 20 patients.

OBJECTIVE: We retrospectively studied 20 adults who underwent C1-C2 transarticular screw (TAS) fixation utilizing frameless stereotaxy. METHODS: The study group comprised 13 men and 7 women, with a mean age of 63 years (range 12-87 years). All patients demonstrated clinical and radiographic evidence of C1-C2 instability. The cause of the instability was trauma in 11 patients, rheumatoid arthritis in 6 patients, failed prior surgery in 2 patients, and congenital malformation in 1 patient. All patients underwent stabilization with C1-C2 TASs using image-guided frameless stereotaxy. RESULTS: There were no new or worsening neurologic symptoms reported at 18-month follow-up. Motor weakness improved in seven of nine patients, myelopathy in seven of seven, and gait in three of six patients in whom these deficits were present preoperatively. Postoperative complications included one surgical site abscess, one cutaneous pressure ulcer, and one iliac crest donor site infection. Of 36 screws placed, 33 (92%) were well positioned. Normal C1-C2 alignment was achieved in 17 of 20 (85%) patients. In 4 of 20 cases, screw implant, which was thought to be anatomically difficult, if not impossible, on the basis of routine magnetic resonance or computed tomography imaging, was actually accomplished successfully using surgical navigation. CONCLUSIONS: C1-C2 TAS placement is a safe and accurate surgical technique that may improve neurologic function. Use of intraoperative navigation can facilitate achieving difficult surgical trajectories that match the patient's anatomy, thus allowing TAS implant in patients who otherwise would not be candidates for this type of internal fixation.

Adolescent↗
PubMedDate not supplied

Identification of acute posttraumatic spinal cord cyst by magnetic resonance imaging: a case report and review of the literature.

Posttraumatic spinal cord cysts have traditionally been diagnosed late. The condition is usually considered after the neurological sequelae of spinal cord trauma have not resolved. The diagnosis has usually required invasive radiographic techniques, or even surgical exploration. Magnetic resonance imaging is a new, non-invasive diagnostic technique that appears to be more accurate than previous procedures. Moreover, it has the ability to delineate spinal cord parenchymal lesions much earlier than other methods. We present a case report and literature review of posttraumatic spinal cord cyst.

Axis, Cervical Vertebra↗
PubMedDate not supplied

Traumatic atlantoaxial subluxation in children.

We report four children who sustained traumatic atlantoaxial subluxation without a rotatory component, underlying congenital anomaly, or inflammatory cause. Three patients were involved in motor vehicle accidents as pedestrians, and one sustained a rugby injury to his neck. Only one patient sustained an associated head injury. Two patients had neurologic signs on admission directly attributable to the atlantoaxial subluxation. The signs resolved after reduction and stabilization of the subluxation. Three patients were treated conservatively and one operatively. To date, all four patients have had a satisfactory outcome.

Accidents, Traffic↗
PubMed1986

The transoral surgical approach to craniovertebral pathology.

The transoral approach is a surgical technique that can be used effectively in the treatment of anterior craniovertebral junction (CVJ) pathology. In this review, we outline the signs, symptoms, and diagnostic studies that identify the pathology and help to determine subsequent therapy. The transoral approach, preoperative and postoperative management problems, and potential complications of the procedure are reviewed. The nursing care of a patient with CVJ pathology is discussed.

Atlanto-Axial Joint↗