A rare case of atlantoaxial rotatory subluxation occurred after pediatric cervical spine surgery performed to remove a dumbbell-shaped meningioma at the level of the C1/C2 vertebrae. This case is classified as a post-surgical atlantoaxial rotatory subluxation, but has a very rare morphology that has not previously been reported. Although there are several reports about post-surgical atlantoaxial rotatory subluxation, an important point of this case is that it might be directly related to the spinal cord surgery in C1/C2 level. On day 6 after surgery, the patient presented with the Cock Robin position, and a computed tomography scan revealed a normal type of atlantoaxial rotatory subluxation. Manual reduction was performed followed by external fixation with a neck collar. About 7 months after the first surgery, the subluxation became severe, irreducible, and assumed an atypical form where the anterior tubercle of C1 migrated to a cranial position, and the posterior tubercle of C1 and the occipital bone leaned in a caudal direction. The pathogenic process suggested deformity of the occipital condyle and bilateral C2 superior facets with atlantooccipital subluxation. A second operation for reduction and fixation was performed, and the subluxation was stabilized by posterior fixation. We encountered an unusual case of a refractory subluxation that was associated with an atypical deformity of the upper spine. The case was successfully managed by posterior fixation.
Congenital Abnormalities ; Humans ; Meningioma ; Neck ; Occipital Bone ; Songbirds ; Spinal Cord ; Spine

Although the pressure gradient (PG) and the effective orifice area (EOA) have been used as indices of prosthetic valve function, these values show correctly neither energy loss, nor increased workload. This study aimed to evaluate the prosthetic valve function using echocardiography and PG, EOA and energy loss index, a new index advocated by Garcia et al. These were calculated for 40 patients with aortic prosthetic valve replacement by SJM valve (19HP, 6 cases; 21mm, 16 cases; 23mm, 14 cases; 25mm, 4 cases). Preoperative and postoperative echocardiographic measurements and their variations were analyzed and compared according to the size of implanted valve. In the comparison before and after aortic valve replacement, left ventricular mass (383±151g vs 288±113g, p<0.01), SV1+RV5 on ECG (5.07±1.73mV vs 3.83±1.5mV, p<0.01), and diastolic left ventricular posterior wall thickness (14.4±3.7mm vs 12.9±2.8mm, p<0.05) decreased significantly after the operation. However, there was no significant difference according to the size of the prosthetic valve in these reduction rates caluculated by (preoperative value-postoperative value)/preoperative value. Small size prosthetic valves were used for patients with small diameter of left ventricular outflow tract (LVOT) (19HP, 18±2mm; 21mm, 21±2mm; 23mm, 23±4mm; 25mm, 27±3mm; p<0.01) and small body surface area (19HP, 1.5±0.2m²; 21mm, 1.5±0.2m²; 23mm, 1.7±0.1m²; 25mm, 1.8±0.1m²; p<0.01) in our study. There was a signifcant difference in EOA (19HP, 1.2±0.4cm²; 21mm, 1.9±0.7cm²; 23mm, 2.2±0.9cm²; 25mm, 3.5±1.1cm²; p<0.01), but not in ELI (19HP, 1.01±0.41cm²/m²; 21mm, 1.87±1.03cm²/m²; 23mm, 1.83±1.09cm²/m²; 25mm, 3.08±1.21cm²/m²; p=0.055) according to the size of the prosthetic valve. Small size prosthetic valves had small EOA, but showed satisfactory valve function in decreasing left ventricular hypertrophy and reducing LVM and ELI of small size was similar to that of large size.

STUDY DESIGN: The strength effects of a pedicle screw-rod system supplemented with a novel cross-link configuration were biomechanically evaluated in porcine spines. PURPOSE: To assess the biomechanical differences between a conventional cross-link pedicle screw-rod system versus a novel cross-link instrumentation, and to determine the effect of the cross-links. OVERVIEW OF LITERATURE: Transverse cross-link systems affect torsional rigidity, but are thought to have little impact on the sagittal motion of spinal constructs. We tested the strength effects in pullout and flexion-compression tests of novel cross-link pedicle screw constructs using porcine thoracic and lumbar vertebrae. METHODS: Five matched thoracic and lumbar vertebral segments from 15 porcine spines were instrumented with 5.0-mm pedicle screws, which were then connected with 6.0-mm rods after partial corpectomy in the middle vertebral body. The forces required for construct failure in pullout and flexion-compression tests were examined in a randomized manner for three different cross-link configurations: un-cross-link control, conventional cross-link, and cross-link passing through the base of the spinous process. Statistical comparisons of strength data were analyzed using Student's t-tests. RESULTS: The spinous process group required a significantly greater pullout force for construct failure than the control group (p=0.036). No difference was found between the control and cross-link groups, or the cross-link and spinous process groups in pullout testing. In flexion-compression testing, the spinous processes group required significantly greater forces for construct failure than the control and cross-link groups (p<0.001 and p=0.003, respectively). However, there was no difference between the control and cross-link groups. CONCLUSIONS: A novel cross-link configuration that features cross-link devices passing through the base of the spinous processes increased the mechanical resistance in pullout and flexion-compression testing compared to un-cross-link constructs. This configuration provided more resistance to middle-column damage under flexion-compression testing than conventional cross-link configuration.
Lumbar Vertebrae ; Pedicle Screws ; Spinal Fusion ; Spine

This is a case of an 81-year-old male who underwent stent-graft (SG) placement for type B aortic dissection at the age of 79. Two and a half years after the surgery, he was diagnosed with SG infection. Although he was scheduled for SG removal and the in-situ replacement of the descending aorta, he had difficulty maintaining oxygenation under single lung ventilation and detaching the severe adhesion of the aneurysm to the lung; therefore, only the aneurysm sac was opened, and abscess drainage was performed. The continuous irrigation and drainage of the aneurysm sac were performed, but the infection did not improve. On the 6th day after the surgery, the aortic aneurysm in the lung adhesion area was left untreated, and an extra-anatomical bypass was performed from the distal aortic arch to the anterior position of the pulmonary hilum, anastomosing with the abdominal aorta. All SGs were removed, the abscess and intima of the aortic aneurysm were extensively excised, and the remaining cavity was filled with omentum. The infection rapidly improved after the surgery, and he was discharged on the 52nd day after admission. Fortunately, the infection did not recur for 2 years since the surgery. This procedure is useful as an option for surgical reconstruction for stent graft infection for which in-situ descending aorta replacement is difficult.