Interbody Bone Graft via Transdiskal Screw Holes as Treatment for High-Grade Spondylolisthesis.

BACKGROUND: Controversy exists regarding surgical treatment of high-grade spondylolisthesis (HGS) in terms of decompression with surgical reduction or in situ fusion. In situ fusion has the advantage of being less technically demanding. However, the residual bone graft area is extremely limited, and posterolateral bone grafting is complex as the transverse process of the slipped vertebrae is located anterior to the sacral ala, which correlates with high rates of pseudoarthrosis. METHODS: Four cases of L5/S1 HGS complaining of low back pain were treated using our new bone graft technique with an exposed osseous end plate. Transdiskal screw holes were made from the S1 pedicle, and bone chips were packed into the L5/S disk space through the screw holes. The slipped L5 vertebra was fixed with a combination of L5/S1 transdiskal and L5 pedicle screws. RESULTS: All cases exhibited good bony fusion, and the low back pain disappeared in all patients up to the 12-month follow-up. This technique involved packing the bone into the closed space, relieving any concerns regarding bone graft migration. CONCLUSIONS: Transpedicular bone graft via transdiskal screw holes is an easy and practical technique for raising the fusion rate in surgical treatment of HGS.

Double-door cervical laminoplasty with suture anchors: evaluation of the clinical performance of the constructs.

PURPOSE: We aimed to investigate the clinical performance of the constructs of double-door cervical laminoplasty with suture anchors by examining bony fusion at the hinges and lamina closure. METHODS: We retrospectively analysed computed tomography (CT) scans obtained preoperatively, immediately after the operation, and at follow-up of patients who underwent cervical laminoplasty using suture anchors. Hinge fracture, bony healing at the hinges, suture anchor failure, and the lamina angle (LA) were evaluated using CT. Lamina closure was defined as an LA <55° at follow-up. RESULTS: A total of 226 laminae and hinges from 37 patients were evaluated. CT scans immediately after the operation revealed that 13 laminae (5.8 %) were fractured, one of which collapsed into the spinal canal. Bony fusion at an average of 12.7 months after the operation was noted at 222 hinges (98.2 %), which was not affected by hinge fracture. One dislodged suture anchor was identified. The mean LAs were 34.4 ± 4.2° preoperatively, 87.4 ± 12.3° immediately after the operation, and 82.5 ± 12.9° at follow-up. At follow-up, four cases of lamina closure were identified (1.8 %), and the closure rate was significantly higher at C3 than at the other levels, although it was not affected by age, sex, causative disease, cervical alignment, suture anchor use, and hinge fracture. CONCLUSIONS: The constructs of double-door cervical laminoplasty with suture anchors are stable with a high rate of fusion at the hinges. However, if the procedure is performed at C3, special modifications should be made to avoid lamina closure.

Accuracy of Pedicle Screw Placement with Robotic Guidance System: A Cadaveric Study.

STUDY DESIGN: A cadaveric study. OBJECTIVE: To investigate the accuracy of pedicle screw placement using a robotic guidance system (RGS). SUMMARY OF BACKGROUND DATA: RGS is a unique surgery assistance-apparatus. Although several clinical studies have demonstrated that RGS provides accurate pedicle screw placement, very few studies have validated its accuracy. METHODS: A total of 216 trajectories performed with the assistance of the RGS in eight cadavers were evaluated. The RGS was used, with different mounting platforms, to drill pilot holes in the thoracic and lumbosacral spine, using 3-mm diameter fiducial wires as trajectory markers. Deviation between the preoperative plan and executed trajectories was measured at the entry points to the vertebrae and at a depth of 30 mm along the wire. Both the deviation from the preoperative plan and the wire position were evaluated in the axial and sagittal planes using computed tomography (CT). RESULTS: The average deviation from the planned wire placement was 0.64 ± 0.59 mm at the entry point and 0.63 ± 0.57 mm at a depth of 30 mm in the axial plane, and 0.77 ± 0.62 mm and 0.80 ± 0.66 mm, respectively, in the sagittal plane. The magnitude of deviation was not affected by the vertebral level or the platform used. The use of an open approach achieved greater screw placement accuracy at a depth of 30 mm in the sagittal plane, compared with the percutaneous approach. The fiducials were placed completely within the pedicle in 93.9% of trajectories in the axial plane (n = 164 pedicles with a width ≥5 mm) and 98.6% in the sagittal plane (n = 216). CONCLUSION: In this cadaveric study, RGS supported execution of accurate trajectories that were equal or slightly superior to reports of CT-based navigation systems. LEVEL OF EVIDENCE: N/A.

Central prostaglandin D(2) stimulates food intake via the neuropeptide Y system in mice.

We found that prostaglandin (PG) D(2), the most abundant PG in the central nervous system, stimulates food intake after intracerebroventricular administration in mice. The orexigenic effect of PGD(2) was mimicked by a selective agonist for the DP(1) receptor among two receptor subtypes for PGD(2), and abolished by its antagonist. Central administration of an antagonist or antisense oligodeoxynucleotide for the DP(1) receptor remarkably decreased food intake, body weight and fat mass. Hypothalamic mRNA levels of lipocalin-type PGD synthase were up-regulated after fasting. The orexigenic activity of PGD(2) was also abolished by an antagonist for neuropeptide Y (NPY) Y(1) receptor. Taken together, PGD(2) may stimulate food intake through central DP(1) receptor coupled to the NPY system.

Angiotensin II and III suppress food intake via angiotensin AT(2) receptor and prostaglandin EP(4) receptor in mice.

Intracerebroventricularly administered angiotensin (Ang) II and III dose-dependently suppressed food intake in mice and their anorexigenic activities were inhibited by AT(2) receptor-selective antagonist. Ang II did not suppress food intake in AT(2) receptor-knockout mice, while it did significantly in wild-type and AT(1) receptor-knockout mice. The suppression of food intake in AT(1) receptor-knockout mice was smaller than that in wild-type. The anorexigenic activities of Ang II and III were also blocked by a selective antagonist for prostaglandin EP(4) receptor. Taken together, centrally administered Ang II and III may decrease food intake through AT(2) receptor with partial involvement of AT(1) receptor, followed by EP(4) receptor activation, which is a novel pathway regulating food intake.