We have developed a cast microfluidic chip for concentration gradient generation that contains a thin (~5 μm^2 crosssectional area) microchannel. Durable 2 μm-high microchannel mold features with a smooth bell-shaped sidewall were fabricated by exposing SU-8 photoresist to diffused 185 nm UV light emitted by a low-cost ozone lamp from the backside of the substrate to ensure sufficient crosslinking of small regions of the SU-8 photoresist. An H-shaped microfluidic configuration was used, in which the thin channel was able to maintain constant diffusion fronts beyond purely static diffusion confirmed with experiment. We also demonstrated the long-term effects of a gradient of nerve growth factor on axon elongation by primary neuronal cells cultured in the microfluidic channel.

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.

Background and Objectives: C-arm free MIS techniques can offer significantly reduced rates of postoperative complications such as blood loss and hospitalization time. Another advantageous long-term aspect is the notably diminished exposure to radiation which is known to cause ma-lignant changes. This study emphasizes that, in some cases of spinal conditions which require a procedural intervention, C-arm free MIS techniques hold stronger indications than open surgeries guided by image intensifier. Materials and Methods: In this research, a retrospective analysis and review of various cervical and thoracic spinal procedures, performed in our hospital, by applying C-arm free techniques. The course of the study explains the basic steps of the procedures and demonstrating postoperative or intra-operative results. For anterior cervical surgery, we performed OPLL resection, while for posterior cervical surgery, we performed posterior fossa decompression for Chiari malformation, minimally invasive cervi-cal pedicle screw fixation (MICEPS) and modified Goel technique with C1 lateral mass screw for atlantoaxial subluxation. Re-garding the thoracic spine, we performed anterior correction for Lenke type 5 scoliosis, and transdiscal screw fixation for DISH fractures. Results: C-arm free techniques are safe procedures that offer precise and high-quality postoperative results by offering sufficient spine alignment and adequate decompression depending on the case. Blood loss, postoperative pain and wound infection are other important aspects of spine surgery that must be always taken into consideration. Conclusions: Navigated C-arm free techniques are safe and precise procedures implemented in the treatment of surgically demanding conditions. They can significantly increase accuracy while decreasing the operative time. They represent the advancement in the field spine surgery and are hailed as the future of the same