Regeneration of intervertebral disc by the intradiscal application of cross-linked hyaluronate hydrogel and cross-linked chondroitin sulfate hydrogel in a rabbit model of intervertebral disc injury.

The degeneration of intervertebral disc (IVD) is a major cause of low back pain. However, there is no satisfactory preventive treatment for degenerative disc disease (DDD). In this study, we examined the effects of a novel cross-linked hyaluronate hydrogel and cross-linked chondroitin sulfate (CS) hydrogel on a rabbit model of IVD injury. We injected 300 microl of phosphate buffer saline, 1% sodium hyaluronate, cross-linked hyaluronate hydrogel, or cross-linked CS hydrogel into the injured IVDs. One, three or six months after treatment, the whole spinal columns were dissected and magnetic resonance (MR) images of the IVDs were examined. It was noted that the IVD, which was injected with cross-linked hyaluronate hydrogel or cross-linked CS hydrogel mostly retained the normal signal intensity of the MR images. These IVDs exhibited a higher degree of staining with safranin-O than the control discs or 1% sodium hyaluronate-injected discs, suggesting that the intradiscal application of cross-linked hyaluronate hydrogel or cross-linked CS hydrogel probably inhibits the degenerative cascade of the DDD. The intradiscal administration of these drugs is safe, easy and costs less. In the near future, these intradiscal injections may become the standard therapy for the treatment of DDD instead of the spine surgeries.

Small-molecule protein tyrosine phosphatase inhibition as a neuroprotective treatment after spinal cord injury in adult rats.

Spinal cord injury causes progressive secondary tissue degeneration, leaving many injured people with neurological disabilities. There are no satisfactory neuroprotective treatments. Protein tyrosine phosphatases inactivate neurotrophic factor receptors and downstream intracellular signaling molecules. Thus, we tested whether the peroxovanadium compound potassium bisperoxo(1,10-phenanthroline)oxovanadate (V) [bpV(phen)], a stable, potent and selective protein tyrosine phosphatase inhibitor, would be neuroprotective after a thoracic spinal cord contusion in adult rats. Intrathecal bpV(phen) infusions through a lumbar puncture rescued dorsal column sensory axons innervating the nucleus gracilis and white matter at the injury epicenter. At the most effective dose, essentially all of these axons and most of the white matter at the epicenter were spared (vs approximately 60% with control infusions). bpV(phen) treatments started 4 h after contusion were fully effective. This treatment greatly improved and normalized sensorimotor function in a grid-walking test and provided complete axonal protection over 6 weeks. The treatment rescued sensory-evoked potentials that disappeared after dorsal column transection. bpV(phen) affected early degenerative mechanisms, because the main effects were seen at 7 d and lasted beyond the treatment period. The neuroprotection appeared to be mediated by rescue of blood vessels. bpV(phen) reduced apoptosis of cultured endothelial cells. These results show that a small molecule, used in a clinically relevant manner, reduces loss of long-projecting axons, myelin, blood vessels, and function in a model relevant to the most common type of spinal cord injury in humans. They reveal a novel mechanism of spinal cord degeneration involving protein tyrosine phosphatases that can be targeted with therapeutic drugs.

New artificial nerve conduits made with photocrosslinked hyaluronic acid for peripheral nerve regeneration.

For peripheral nerve regeneration, three-dimensional distribution and growth of cells within the porous scaffold are of clinical significance. We demonstrate that cultured rat Schwann cells and neurospheres grow in vitro on new artificial nerve conduits made with photocrosslinked hyaluronic acid (HA). HA tubular conduits have an inner diameter of 1.2 mm with porous nano-structure of 50 microm. After 3 weeks of cultivation, HA conduits remained circular with a round lumen, and construct of cell-conduits maintained the size and shape of the original architecture of the tube. HA itself has the function to facilitate a pathway for cellular and axonal ingrowth during peripheral nerve regeneration. These findings provide the feasibility of using the HA conduits for better cell adhesion and differentiation, leading to axonal regeneration in peripheral nerve reconstruction.

Dorsal column sensory axons lack TrkC and are not rescued by local neurotrophin-3 infusions following spinal cord contusion in adult rats.

By reducing the progressive degeneration and disconnection of axons following spinal cord injury the functional outcome should improve. After direct transection of dorsal column sensory axons, neurotrophin-3 (NT-3) treatment can reduce degeneration and promote regeneration of the proximal stumps. Here, we tested in adult rats whether NT-3 infusion at the site of a moderate T9 spinal cord contusion would rescue sensory connections to the gracile nucleus in the medulla. Sensory projections were anterogradely traced bilaterally with injections of cholera toxin B (CTB) into the sciatic nerve 3 days before analysis. Seven days after the contusion plus intrathecal (subarachnoid) vehicle infusion as a control, the CTB-positive innervation of the gracile nucleus was reduced to approximately 25% of sham-operated rats. Intrathecal infusion of 10 microg/day of NT-3 did not affect this reduced innervation. To ensure good tissue penetration and high concentrations of NT-3 early after the injury, other rats received intraparenchymal infusions of vehicle or NT-3 near the injury site starting 2 days before until 7 days after the injury. This NT-3 treatment also did not affect the reduced innervation. This suggests that local NT-3 treatments cannot protect sensory axons from secondary degeneration after a contusive spinal cord injury. These results are likely because TrkC is not present in axons of the dorsal columns or gracile nucleus, or in other dorsal column cell types, even after the contusion. Together with published results, our data suggest that NT-3 is a peripherally--but not centrally--derived neurotrophic factor for sensory neurons.

Comparison of surgical outcomes between macro discectomy and micro discectomy for lumbar disc herniation: a prospective randomized study with surgery performed by the same spine surgeon.

STUDY DESIGN: A prospective study was conducted on the surgical procedures for lumbar disc herniation. OBJECTIVE: The objective of this study is to investigate the surgical outcomes of different methods when performed by the same surgeon, using a prospective study. BACKGROUND: Macro discectomy is widely known as a common surgical procedure for lumbar disc herniation, while microdiscectomy in place of Caspar technique (the Caspar method) and microendoscopic discectomy by a posterior approach are reported as less invasive surgical methods for this condition. However, there have not been a significant number of prospective studies conducted to compare different surgical procedures for lumbar disc herniation. MATERIALS AND METHODS: The target of our study was a group of 62 patients (male: 43, female: 19) who underwent surgery by macro discectomy (A group) and 57 patients (male: 33, female: 24) who underwent surgery by microdiscectomy in place of Caspar technique (B group). The mean ages at surgery were 34 (14 to 62) years and 41 (18 to 65) years respectively, and the mean duration of follow-up was 2 years and 8 months (12 months to 4 years). For all patients, the surgery was performed by 1 of the authors. The items investigated were the operation time, amount of bleeding, duration of hospitalization, amount of analgesic agent used after surgery, pre- and postoperative scores based on judgment criteria for treatment of lumbar spine disorders established by the Japanese Orthopaedic Association score, visual analog scales (VAS, 0 to 10) for lumbago before surgery and at discharge, VAS for sciatica before surgery and at discharge, perioperative complications, and cases requiring further surgery. RESULTS: There were no significant differences between the 2 surgical procedures in the frequency of use of an analgesic agent after surgery, the pre- and postoperative Japanese Orthopaedic Association scores or postoperative VAS for sciatica. Statistically significant differences were observed in the operation time, amount of bleeding, duration of hospitalization, and postoperative VAS for lumbar pain, but the differences were not large, and may not have been clinically significant. CONCLUSIONS: For herniotomy for lumbar disc herniation, both macro discectomy and microdiscectomy are appropriate, as long as surgeons have mastery of the procedures.

Simultaneous registration with ct-fluoro matching for spinal navigation surgery. A case report.

Computer-assisted surgery, which provides simultaneous, multiplanar images of bone structures, has become widely used. However, registration maneuvering remains time consuming. The objective of this paper is to document the usefulness of CT-fluoro matching for spinal navigation. A spinal navigation system (VECTORVISION compact; Brain LAB, Germany) and a digital imaging system (OEC9800; CATHEX, Tokyo, Japan) were used for CT-fluoro matching in cases of L4/5 and L5/S1 posterior lumbar interbody fusion. A reference array was attached to the L4 spinous process. Preoperative CT images and intraoperative fluoro-shots including L4, L5, and S1 were superimposed on the navigation monitor. Following insertion of L4 screws, a reference array remained to be attached to the L4 spinous process, after which a level definition and pre-registration of L5 and S1 vertebrae were performed and the screwing procedure of L5 and S1 was completed without additional fluro-shots. Registration of three vertebrae was completed without paired-point or surface-matching procedures. The calculation time for the registration in a single vertebra was 30 sec. All pedicle screws were seen to be successfully inserted on postoperative CT images. We performed the navigation surgery by matching the preoperative CT images to the intraoperative fluoro-shots without manual registration. This technique may prove useful in the future for anterior spinal surgery and percutaneous screwing without the need for total exposure of the bone surface.

The effect of autologous fibrin tissue adhesive on postoperative cerebrospinal fluid leak in spinal cord surgery: a randomized controlled trial.

STUDY DESIGN: A prospective randomized study evaluating the efficacy of autologous fibrin tissue adhesive for decreasing postoperative cerebrospinal fluid (CSF) leak in spinal cord surgery. OBJECTIVE: To compare postoperative CSF leak in 3 groups (i.e., autologous fibrin tissue adhesive used, commercial fibrin glue used, and no fibrin tissue adhesive used) of patients undergoing spinal surgery who needed dural incision. SUMMARY OF BACKGROUND DATA: Spinal cord operations, particularly when dural incision is inevitable, sometimes involve postoperative CSF leak. Because CSF leak is a serious complication, countermeasure is necessary to prevent it after dural suture. Commercial fibrin tissue adhesive was formerly used. Because the possibility of prion infection was widely noticed, commercial fibrin tissue adhesive containing animal components has been used less often. METHODS: In 13 of 39 cases in which dural incision would be made, 400 mL whole blood was drawn, and autologous fibrin tissue adhesive was made of plasma. Cases were divided into 3 groups: (1) dural closure alone, (2) use of autologous fibrin tissue adhesive after dural closure, and (3) use of commercial fibrin tissue adhesive after dural closure. The primary outcome measure was determined as postoperative (3 days) volume of drainage fluid, and results were analyzed using the analysis of variance. The secondary outcome measure was general blood test, coagulation assay, and plasma fibrinogen, and these were analyzed also using the analysis of variance. RESULTS: There was a significant difference in the primary outcome between the autologous and control groups. No complications such as infection or continuous CSF leak were observed in any case. The mean volume of drainage fluid was 586.2 mL in the group with autologous fibrin tissue adhesive and 1026.1 mL in the group without fibrin tissue adhesive. The volume of drainage fluid was significantly lower in the former group than that in the latter group. There was no statistical difference between the volumes of the group with autologous adhesive and with commercial adhesive (639.2 mL). CONCLUSIONS: We used autologous fibrin tissue adhesive as a new sealant after dural closure instead of commercial fibrin tissue adhesive. No definitive CSF leak was observed, and the volume of drainage fluid was significantly lower in the group with autologous fibrin tissue adhesive than that in the group without fibrin tissue adhesive. The use of autologous fibrin tissue adhesive was superior to that of commercial fibrin tissue adhesive in cost.

Expression of GDNF in spinal cord injury and its repression by ONO-1714.

ONO-1714 is a newly developed specific inhibitor for inducible nitric oxide synthase (iNOS). We have shown that ONO-1714 has some neuroprotective effects. In this report, we investigated the effects of ONO-1714 in injured spinal cords, and analyzed the expression of glial cell-line-derived neurotrophic factor (GDNF) after injury. Male Sprague-Dawley rats were subjected to contusive spinal cord injury and administrated 0.1 mg/kg ONO-1714. The injured spinal cords were isolated at appropriate time points and GDNF mRNA was determined by semi-quantitative RT-PCR. GDNF-positive cells were also counted after immunohistochemical stainings. ONO-1714 diminished the early stage production of GDNF after injury as well as it reduced the production of nitric oxide produced by iNOS and apoptotic cells.

Effects of MPSS and a potent iNOS inhibitor on traumatic spinal cord injury.

ONO-1714, a selective inhibitor of inducible nitric oxide synthetase (iNOS) attenuated the increase of apoptosis and improved the functional outcome of urinary bladder after traumatic spinal cord injury. These findings suggest that iNOS plays a role in the process of SCI. Early treatment with 30 mg/kg methylprednisolone sodium succinate (MPSS) could also inhibit the expression of iNOS gene, apoptosis and the loss of urinary bladder function. We confirmed that early MPSS treatment may prevent injury associated with apoptosis and urinary bladder disability by reducing iNOS mRNA. However, delayed single MPSS treatment 8 h after spinal cord injury was not effective. Early repeated MPSS treatment might allow greater recovery from acute spinal cord injury.

Suppression of GDNF production by MPSS treatment following spinal cord injury in the rat.

The synthetic glucocorticosteroid methylprednisolone sodium succinate (MPSS) has been clinically used for the treatment of acute spinal cord injury (SCI) to promote the recovery of neurological functions. However, the mechanisms of its beneficial actions are not entirely understood. Experimental evidence suggests that MPSS may contribute to some extent to neuroprotection in SCI. On the other hand, glial cell line-derived neurotrophic factor (GDNF) acts as a potent survival factor for several neuronal populations, providing a therapeutic promise for neurological disorders. This experiment demonstrated, for the first time, the time-effect relationship of MPSS on GDNF gene expression and protein synthesis in the injured spinal cord tissues.