Cervical Vertebrae/surgery* ; Drainage ; Humans

Cervical Vertebrae ; surgery ; Humans ; Spondylosis ; classification ; diagnosis ; surgery

Hangman's fractures are located in the region between facets of the axis, which are accompanied by an increasing rate recently. However,there are no uniform standards for the treatment, especially for the treatment of fractures of types II and IIa because the operative approaches which include anterior and posterior are supported by different groups. The article tried to make an analysis on pathological anatomy, mechanism, types and surgical treatment of Hangman's fractures.
Cervical Vertebrae ; injuries ; surgery ; Humans ; Spinal Fractures ; classification ; surgery

Humans ; Osteoblastoma/surgery* ; Neck/surgery* ; Spinal Neoplasms ; Cervical Vertebrae

OBJECTIVETo evaluate stress changes of intervertebral space and adjacent intervertebral space after artificial disc replacement with angles.

METHODSArtificial disc replacement with angles were designed according to existing data. Axial pressure, flexion/extension, lateral bending and torsion loading were applied on finite element models of normal cervical discs on C4,5 segments, C4,5 segments with 0 degrees artificial cervical discs and C4,5 segments with 10 degrees artificial cervical discs, then stress changes of C4,5 space was observed. The same loadings were applied on finite element models of normal cervical discs on C4-C6 segments, C4,5 segments with 0 degrees, C4,5 segments with 10 degrees, then stress changes of replaced segments space and adjacent segment space were observed.

RESULTSFor C4,5 segments, 80 MPa/0 degrees artificial discs and 80 MPa/10 degrees artificial discs had the similar equivalent shear stress (Se), and were both larger than that of normal discs, when lateral bending were performed, 80 MPa/0 degrees artificial discs were closed to normal discs when axial pressure and flexion/extension were carried out, while 80 MPa/10 degrees artificial discs had a larger Se than that of normal ones,when torsion loading were applied, Szx/Szy stress of 80 MPa/0 degrees and 80 MPa/10 degrees artificial discs were closed to normal ones. For C4-C6 segments, the axial pressure, flexion/extension and lateral bending of C5,6 were all lower than normal discs after C4,5 discs were replaced by 80 MPa/10 degrees artificial discs, while Szx/Szy of torsion loading were closed to normal ones.

CONCLUSIONArtificial discs with 10 degrees have less influences on stress of adjacent intervertebral space and closer to mechanical property after being implanted into intervertebral space.

Cervical Vertebrae ; surgery ; Humans ; Stress, Mechanical ; Total Disc Replacement ; methods

BACKGROUNDTransfacet pedicle screws provide another alternative for standard pedicle screw placement for plate fixation in the lumbar spine. However, few studies looking at transfacet pedicle screw fixation in the cervical spine are available. Therefore, cervical transfacet pedicle screw fixation and standard pedicle screw fixation techniques were biomechanically compared in this study.

METHODSTen fresh human cadaveric cervical spines were harvested. On one side, transfacet pedicle screws were placed at the C3-4, C5-6, and C7-T1 levels. On the other side, pedicle screws were placed at the C3, C5, and C7 levels. The screw insertion technique at each level was randomized for right or left. The starting point for the transfacet pedicle screw insertion was located at the midpoint of the inferolateral quadrant of the lateral mass and the direction of the screw was about 50 degrees caudally in the sagittal plane and about 45 degrees toward the midline in the axial plane. Screws were placed from the inferior articular process, across the facet complex and the pedicle into the body of the caudal vertebra. The entry point for the pedicle screw was located at the midpoint of the superolateral quadrant of the lateral mass, and the direction of the screw was about 45 degrees toward the midline in the axial plane and toward the upper third of the vertebral body in the sagittal plane. After screw placement we performed axial pullout testing.

RESULTSAll the cervical transfacet pedicle screws and the pedicle screws were inserted successfully. The mean pullout strength for the transfacet pedicle screws was 694 N, while for the pedicle screws 670 N (P=0.013). In all but six instances (10%), the pedicle screw pullout values exceeded the values for the transfacet pedicle screws; this occurred three times at the C3/C4 level, twice at the C5/C6 level and once at the C7/T1 level. The greatest pullout strength difference at a single level was observed at the C5/C6 level, with a mean difference of 38 N (t=-1.557, P=0.154). The C7/T1 level had a mean difference of 26 N and the C3/C4 level had a mean difference of 14 N.

CONCLUSIONSCervical transfacet pedicle screws exhibited higher pullout strength than pedicle screws. Posterior transfacet pedicle screw fixation in the cervical spine may afford an alternative to standard screw placement for plate fixation and cervical stabilization.

Biomechanical Phenomena ; Bone Screws ; Cervical Vertebrae ; physiology ; surgery ; Humans

OBJECTIVETo ascertain an accurate approach to inserting the pedicle screw into C3-C7 segments of the cervical vertebra.

METHODSAnatomic morphology of lateral mass and pedicle, and their anatomic relationship with the adjacent tissue were observed on C3-C7 segments of 25 adult embalmed cadavers (50 sides).

RESULTS1) The inferior edge of the base of the posterior tubercle of the transverse process and the inferior edge of the pedicle were connected with each other on 25 adult embalmed cadavers (50 sides). The transverse section which passed through the median point between the superior edge and the inferior edge of the base of the posterior tubercle of the transverse process, and the transverse section which passed through the central axis between the superior edge and the inferior edge of the pedicle, were in the same horizontal plane. The superior and inferior position of placing the pedicle screw was determined by this transverse section, which passed through the median point between the superior and the inferior edge of the base of the posterior tubercle of the transverse process. 2) There was a directed internal-downwards "triangular sulcule" between the base of the posterior tubercle of the transverse process and the anterolateral edge of the inferior articular process. The anterior wall of the triangular sulcule was the base of the posterior tubercle of the transverse process, the posterior wall was the anterolateral edge of the inferior articular process, and the bottom of the sulcule was connected with the interior edge of the pedicle. The vertical length between the top of triangle and the planes of inferior edge of the pedicle was (2.78+/-1.71) mm. The inferior edge of the cervical pedicle could be detected using a blunt probe along the "triangular sulcule" between the base of the posterior tubercle of the transverse process and the anterolateral edge of the inferior articular process in surgical operation. 3) The lateral fovea of the articular process was observed on all lateral masses (50 sides). The internal and external position of the entrance point could depend on anatomic landmarks: the lateral edge of the lateral fovea of the articular process. The horizontal length between the lateral fovea of the articular process and the entrance point was (3.14+/-1.45) mm. 4) The diameter of pedicle screw, about (2.78+/-1.71) mm, was the transverse diameter of the cancellous bone of the greatest narrow part of the cervical pedicle.

CONCLUSIONSThe median point between the superior edge and the inferior edge of the base of the posterior tubercle of the transverse process, the lateral fovea of the articular process, and the triangular sulcule between the base of the posterior tubercle of the transverse process and the anterolateral edge of inferior articular process, are easy to be exposed and identified in surgical operation. The pedicle screw can be precisely inserted through this method.

Adult ; Bone Screws ; Cervical Vertebrae ; anatomy & histology ; surgery ; Humans

Humans ; Post-Traumatic Headache/etiology* ; Risk Factors ; Cervical Vertebrae/surgery*

OBJECTIVETo investigate appropriate ways for screw placement of pedicle of vertebral arch in the horizontal plane.

METHODSFifteen preserved thoracolumbar spine specimens (T(11)-L(5)) were used and divided into three groups at random. Firstly four anatomic parameters indicating screw positions in the horizontal plane were measured. Secondly the methods of Roy-camille, Magerl, and authors' segmental differences were used to place successively the screws of the pedicles with 5 mm, 6 mm, and 7 mm in diameter. Coincidences between the drilling point, drilling direction and pedicle axis, and ruptures of the pedicle as well as the length of the screw in the vertebral body were observed.

RESULTSFour anatomic parameters at various segments showed significant differences (P<0.05). The drilling point by the Roy-camille's method deviated medial to pedicle axis in most segments, and its drilling direction did not coincide well with most E-angles of the pedicles. The drilling point by Magerl's method coincided relatively well with pedicle axis in lumbar vertebrae, but there were still some differences between its drilling direction and E-angles of the pedicles. The method of segmental differences coincided the best with the pedicle axis. The lengths of screw in the vertebra were relatively long by both Magerl and segmental difference methods. When 5 mm diametral screw was used by the three methods, the rupture rate was very low. When 6 mm and 7 mm diametral screws were placed, the rupture rate was accordingly increased. Of the three methods, Roy-camille's method showed a relatively high rupture rate, while the method of segmental differences a comparatively low rupture rate. Various degrees of rupture of the pedicle of vertebral arch were found at the juncture of the thoracic and lumbar vertebrae when 6 mm or 7 mm diametral screws was used by any screw placement method. In contrast, the rupture was seldom seen at the lower lumbar vertebrae when 7 mm diametral screws were used.

CONCLUSIONSThe segmental difference method is proved to have the anatomic safety and screw biomechanical stability. It is appropriate to choose different diametral screws, different drilling points and directions according to different segments of the vertebra.

Adult ; Bone Screws ; Cervical Vertebrae ; injuries ; Humans ; Lumbar Vertebrae ; injuries ; Spinal Injuries ; surgery

OBJECTIVETo investigate the efficacy of percutaneous vertebroplasty in the treatment of vertebral hemangioma.

METHODSSeven patients with vertebral hemangiomas were treated by percutaneous vertebroplasty, including one case of cervical, three cases of thoracic, and three cases of lumbar hemangiomas. The average score of the 6-point behavioral pain rating scale was 2.67 +/- 0.41, and the average score of ambulation was 2.83 +/- 0.33. Guilty vertebral bodies were orientated with fluoroscopy. The procedures were performed under local anesthesia. The image features were also analyzed. Unipedicular or bipedicular approaches were used in 6 cases of thoracic and lumbar hemangiomas. The cervical anterior-lateral approach was adopted in one case of cervical hemangioma. 4-7 ml of 15%-20% bone cement was mixed and injected into the vertebral body to form a cast in the lesions. Re-examination of clinical symptoms, plain film, and CT were made for 1, 3, and 9 months of post-procedure follow-up.

RESULTSGood results were achieved in all the seven cases. Pain was completely relieved in 5 cases and partially relieved in 2 cases. Symptom was also recovered in 2 patients with radiculopathy. No recurrence was found after 1-9 months of postoperative follow-up.

CONCLUSIONTreatment of vertebral hemangioma with percutaneous vertebroplasty is safe and effective with minimal invasion.

Adult ; Cervical Vertebrae ; surgery ; Female ; Follow-Up Studies ; Hemangioma ; surgery ; Humans ; Lumbar Vertebrae ; surgery ; Male ; Middle Aged ; Orthopedic Procedures ; methods ; Pain Measurement ; Spinal Neoplasms ; surgery ; Thoracic Vertebrae ; surgery