Transpedicle osteotomy positioning in pedicle-lengthening laminoplasty.

Pedicle-lengthening laminoplasty is a new minimally invasive technique for surgical treatment of lumbar spinal stenosis. The procedure is performed with the assistance of fluoroscopy and involves creating a pedicle passage, transpedicle osteotomy from inside the pedicle passage and lengthening it by using an implant bilaterally to enlarge the spinal canal and neural foramen. A critical component of the procedure is the precise determination of the osteotomy site on the pedicle. The objective of this study was to examine in vitro whether fluoroscopic positioning could be used to guide the osteotomy and to define the cutting site in the pedicle-lengthening laminoplasty in relation to the posterior vertebral line. It was found that the osteotomy site was from 2.0 to 3.5 mm posterior to the posterior vertebral line. The maximum difference between the measured value and that theoretically simulated on 3-dimensional (3D) computed tomography reconstruction was 0.3 mm. The spinal canal cross-sectional area was significantly enlarged after pedicle-lengthening. Accurate placement of the osteotomy is critical in pedicle-lengthening laminoplasty. Guiding the positioning of the osteotomy based on the posterior vertebral line images provides satisfactory accuracy, suggesting a possible clinical application for our technique; however, further verification in vivo is needed.

Simultaneous bilateral quadriceps tendon rupture in a patient with hyperparathyroidism undergoing long-term haemodialysis: a case report and literature review.

Simultaneous bilateral quadriceps tendon rupture is a rare injury that represents < 5% of all quadriceps tendon ruptures. It is generally associated with chronic metabolic disorders and is seen in patients with uraemia undergoing maintenance haemodialysis. The present case was a 46-year-old man who presented with pain and the inability to extend his knees following a minor accident. A physical examination combined with X-radiography and magnetic resonance imaging investigations resulted in a diagnosis of bilateral quadriceps tendon rupture. He had a history of uraemia and had received regular haemodialysis for 7 years. He had high levels of serum parathyroid hormone and he was diagnosed with secondary hyperparathyroidism. Following surgical repair of both quadriceps tendons, in addition to management of the secondary hyperparathyroidism, the patient regained full active mobility of both knee joints and was able to participate in normal activities of daily living.