Study design : Technical note. Objectives: To present a new spinal shortening technique for tethered cord syndrome. Background : Tethered cord syndrome (TCS) is a debilitating condition of progressive neurological decline. Surgical detethering for TCS is a gold standard. However, symptomatic retethering of TCS has been reported in 5%–50% of patients after initial release. To solve this problem, posterior spinal shortening osteotomy has been reported. This technique has risks of massive blood loss and neurological deterioration. The authors hereby report a new safe spinal shortening technique for tethered cord syndrome. Materials and Methods : A 31-year-old man with gait disturbance was referred to our hospital. After the delivery, he underwent surgical untethering of spinal cord in another hospital. He had hyperreflexia of Achilles tendon reflex and muscle weakness of bilateral legs (MMT 3-4). He also had urinary and bowel incontinence, and total sensory loss below L5.Anteroposterior lumbar radiogram indicates partial laminectomy of L3 and L4. Lumbar MRI showed retethering of spinal cord. Results: He underwent new spinal shortening technique for tethered cord syndrome under the guidance of O-arm navigation. First, from anterior approach disectomy from T12 to L3 was performed. Second, from posterior Ponte osteotomy was done from T12 to L3, shorten the spinal column 15 mm. The patient was successfully treated surgically. Postoperative lumbar MRI showed the tension of spinal cord was released. Manual muscle testing results and sensory function of the left leg had recovered almost fully on final follow-up at one year. Conclusions/Level of Evidence: Retethered spinal cord after initial untethering was difficult to treat. This new spinal shortening technique was effective and very safe technique to release the tension of spinal cord. Level V.

Study design: Technical note. Objectives: To present a new technique of treatment for a patient with thoracolumbar focal kyphosis due to osteoporotic verte-bral fracture (OVFs). Background : OVFs are common among the elderly population. Following a severe wedged fracture, patients often experience low back pain and disruptions in activities of daily living. Reconstruction surgeries, such as corpectomy, are among the treatment options for this condition. However, corpectomy requires longer surgical times and involves a significant amount of blood loss. Materials and Methods : An 80-year-old woman presented to our hospital with severe low back pain and gait disturbance. She had experienced an L2 OVF six years prior. Although she had no neurological deficit, she could not walk more than 200m due to pain. Preoperative spinal radiographs revealed severe sagittal malalignment, with the L2 vertebra collapsed and focal kyphosis of L1-3 measuring 34 degrees. Results: The patient underwent anterior and posterior surgery in the right decubitus position using a C-arm free technique. The surgical time was 133 minutes with an estimated blood loss of 100 ml. Hyperlordotic cages were inserted in the upper and lower disc space via a lateral approach, while percutaneous pedicle screws (PPS) were inserted from a posterior approach. These procedures were performed simultaneously under navigation guidance only. Post-operative images showed excellent spinal alignment, with local kyphosis reduced from 34 to 14 degrees, and no major or severe complications occurred. At one-year follow-up, the patient was able to walk smoothly, with her visual analogue scale for low back pain improving from 73mm to 13mm, and her Oswestry Disability Index improving from 53.3% to 13.3%. Conclusions/Level of Evidence : The simultaneous use of hyperlordotic cages and PPS is an effective and innovative navigation technique that yields promising outcomes for thoracolumbar focal kyphosis resulting from OVFs. This approach not only reduces surgical time but also minimizes intraoperative blood loss. Level V.