Atlanto-Axial Joint ; physiopathology ; Humans ; Joint Diseases ; physiopathology ; therapy ; Musculoskeletal Manipulations

OBJECTIVETo compare the biomechanical performances of different wires and cable fixation devices in posterior instrumentation for atlantoaxial instability, and test the effect of different fixation strengths and fixation approaches on the surgical outcomes.

METHODSSix specimens of the atlantoaxial complex (C0-C3) were used to establish models of the normal complex, unstable complex (type II odontoid fracture) and fixed complex. On the wd-5 mechanical testing machine, the parameters including the strength and rigidity of anti-rotation, change and strength of stress, and stability were measured for the normal complex, atlantoaxial instability complex, the new type titanium cable fixation system, Atlas titanium cable, Songer titanium cable, and stainless wire.

RESULTSThe strength and rigidity of anti-rotation, change and strength of stress, stability of flexion, extension and lateral bending of the unstable atlantoaxial complex fixed by the new double locking titanium cable fixation system were superior to those of the Songer or Atlas titanium cable (P<0.05) and medical stainless wire (P<0.05). Simultaneous cable fastening on both sides resulted in better fixation effect than successive cable fastening (P<0.05). Better fixation effect was achieved by fastening the specimen following a rest (P<0.05).

CONCLUSIONSThe fixation effects can be enhanced by increased fastening strengths. The new type double locking titanium cable fixation system has better biomechanical performance than the conventional Songer and Atlas titanium cables. Fastening the unstable specimens after a rest following simultaneous fastening of the specimen on both sides produces better fixation effect.

Atlanto-Axial Joint ; physiopathology ; surgery ; Biomechanical Phenomena ; Bone Wires ; Cadaver ; Humans ; Internal Fixators ; Joint Instability ; physiopathology ; surgery ; Orthopedic Fixation Devices

OBJECTIVETo compare the anti-rotation biomechanical performances of wire and various cable fixation devices currently used in the posterior Brooks instrumentation for atlantoaxial instability.

METHODSIn this experiment,six specimens of the atlantoaxial complex (Occipital-C3) were used. The models of the normal complex,unstable complex (type II odontoid fracture) and fixed complex were established. On the WD-5 mechanics experimental machine,the parameters including the strength and rigidity of anti-rotation were quantified for the normal complex (group N),the atlantoaxial instability complex (group M), the new type Titanium cable (group A), Atlas titanium cable (group B), Songer Titanium cable (group C), stainless wire(group D).

RESULTSThe max strength of A, B, C, D groups was 12.5, 11.3, 11.52, 11.55 N x m respectively, the max rigidity was 58.81, 53.17, 54.11, 54.35 N x cm/deg respectively. The strength and rigidity of anti-rotation, compare to the unstable atlantoaxial complex which were fixed by the new double locking Titanium cable fixation system were superior to those of normal complex, instability complex, Songer or Atlas Titanium cable (P < 0.05).

CONCLUSIONHaving been changed the locking method, the anti-rotation biomechanical characteristics of the new type double locking Titanium cable fixation system are superior or similar to the traditional Songer or Atlas Titanium cable.

Atlanto-Axial Joint ; physiopathology ; surgery ; Biomechanical Phenomena ; Bone Wires ; Humans ; Joint Instability ; physiopathology ; surgery ; Orthopedic Fixation Devices ; Rotation

OBJECTIVETo analyze appropriate strategy about treatment of rotatory dislocation of atlantoaxial articulation in children.

METHODSFrom March 2005 to February 2009, 36 patients with rotatory dislocation of atlantoaxial articulation were retrospectively analyzed, including 25 males and 11 females, with the average age of 7.8 years (ranged 3 - 14 years). According to Fielding-Hawkins clinical classification, type I 24 cases, type II 8 cases, type III 2 cases, type IV 2 cases. All of the patients were assessed rotatory dislocation of atlantoaxial articulation and whether or not upper cervical spine malformation by X-ray, MRI and CT scan and three-dimensional reconstruction. Thirty-two cases received observational treatments which were reduction after cervical traction, without appearance of the deformity, without neurological symptoms. And another 4 serious cases (irreducible atlantoaxial dislocation or with os odontoideum) received posterior atlantoaxial fixed autograft fusion.

RESULTSRotation of atlas decreased from 16.0° ± 4.4° (range, 5° to 26°) pre-therapy to 4.5° ± 1.5° (range, 0° to 8°) post-therapy in 35 cases, rotation of atlas had significant difference between pre-therapy and post-therapy (t = 14.75, P < 0.05). One patient pre-therapy rotation of atlas was 45°, post-therapy was 4°. All patients were followed up for 14 - 38 months (mean, 18 months), 32 cases who received cervical traction and external fixation resulted in satisfactory outcome in which all the ankylodeire were disappear, bilateral masses were symmetrical on anterior-posterior and good functional activities of cervical. All the 4 cases surgically treated obtained reduction, sound bony fusion and neural symptoms were improved obviously after operation.

CONCLUSIONSConservative treatment has been proved to be very effective in most of rotatory dislocation of atlantoaxial articulation in children. However, operative treatment should be considered in the following situations: irreducible atlantoaxial dislocation or patients with os odontoideum.

Adolescent ; Atlanto-Axial Joint ; abnormalities ; physiopathology ; Child ; Child, Preschool ; Congenital Abnormalities ; Female ; Humans ; Joint Dislocations ; surgery ; therapy ; Male ; Retrospective Studies

Atlanto-Axial Joint ; pathology ; physiopathology ; Child, Preschool ; Female ; Humans ; Joint Dislocations ; etiology ; Tomography, X-Ray Computed ; Wounds and Injuries ; complications

Adolescent ; Adult ; Atlanto-Axial Joint ; injuries ; physiopathology ; Child ; Child, Preschool ; Female ; Follow-Up Studies ; Humans ; Joint Dislocations ; physiopathology ; surgery ; therapy ; Male ; Rotation

Antirheumatic Agents ; therapeutic use ; Arthritis, Rheumatoid ; complications ; drug therapy ; Atlanto-Axial Joint ; injuries ; Humans ; Joint Dislocations ; etiology ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Syringomyelia ; diagnosis ; etiology ; physiopathology

Retropharyngeal calcific tendinitis is defined as inflammation of the longus colli muscle and is caused by the deposition of calcium hydroxyapatite crystals, which usually involves the superior oblique fibers of the longus colli muscle from C1-3. Diagnosis is usually made by detecting amorphous calcification and prevertebral soft tissue swelling on radiograph, CT or MRI. In this report, we introduce a case of this disease which was misdiagnosed as a retropharyngeal tuberculous abscess, or a muscle strain of the ongus colli muscle. No calcifications were visible along the vertical fibers of the longus colli muscle. The lesion was located anterior to the C4-5 disc, in a rheumatoid arthritis patient with atlantoaxial subluxation. Calcific tendinitis of the longus colli muscle at this location in a rheumatoid arthritis patient has not been reported in the English literature.
Adult ; Arthritis, Rheumatoid/*complications ; Atlanto-Axial Joint/*physiopathology ; Calcinosis/*complications/*diagnosis ; Diagnosis, Differential ; Dislocations/*complications ; Female ; Humans ; *Magnetic Resonance Imaging ; Pharyngeal Diseases/*complications/*diagnosis ; Tendinopathy/*complications/*diagnosis

Adult ; Atlanto-Axial Joint ; surgery ; Bone Screws ; Female ; Fractures, Bone ; diagnostic imaging ; pathology ; physiopathology ; surgery ; Humans ; Male ; Middle Aged ; Odontoid Process ; injuries ; Tomography, X-Ray Computed

OBJECTIVETo explore the feasibility of C1-2 pedicle screw fixation and fusion technique in treating atlantoaxial instability.

METHODSFrom January 2006 to January 2009,18 patients with atlantoaxial instability were treated with C1-2 pedicle screws and plates fixation under general anesthesia. There were 11 males and 7 females, the age for 17-62 years with the mean of 37.7 years. The course of disease was from 3 days to 30 months with an average of 10.6 months. The patients had different degrees neck pain and disturbance of sensation or (and) dyskinesia, had atlantoaxial instability from images before operation. The JOA scoring before operation were from 8 to 15 with an average of 11.4. Bone fusion of patients was observed with X-rays, CT and MR image at the same time after operation and the JOA scoring was compared with preoperative.

RESULTSA total of 72 screws were successfully placed in 18 cases, among them, 15 cases were followed up from 6 to 24 months with an average of 11.5 months. Fifteen cases obtained bone fusion with time for 3-6 months without the complications of internal fixation failure or redislocation of atlas. The spinal compression had differently improved, postoperative JOA scoring was from 12 to 17 scores with an average of 14.5 scores.

CONCLUSIONPedicle screw fixation and fusion in atlas has advantages of firm fixation and high fusion rate, it is a better choices for atlantoaxial instability. It is not suitable for variations of sulcus of vertebral artery of atlas and posterior arch of atlas.

Adolescent ; Adult ; Atlanto-Axial Joint ; injuries ; physiopathology ; surgery ; Bone Plates ; Bone Screws ; Female ; Fracture Fixation, Internal ; Humans ; Male ; Middle Aged ; Treatment Outcome ; Young Adult