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To study if spinal motor evoked potentials (SpMEPs), muscle responses after electrical stimulation of the spinal cord, can monitor the corticospinal tract. Study 1 comprised 10 consecutive cervical or thoracic myelopathic patients. We recorded three types of muscle responses intraoperatively: (1) transcranial motor evoked potentials (TcMEPs), (2) SpMEPs and (3) SpMEPs + TcMEPs from the abductor hallucis (AH) using train stimulation. Study 2 dealt with 5 patients, who underwent paired train stimulation to the spinal cord with intertrain interval of 50-60 ms for recording AH SpMEPs. We will also describe two illustrative cases to demonstrate the clinical value of AH SpMEPs for monitoring the motor pathway. In Study 1, SpMEPs and SpMEPs + TcMEPs recorded from AH measured nearly the same, suggesting the collision of the cranially evoked volleys with the antidromic signals induced by spinal cord stimulation via the corticospinal tracts. In Study 2, the first and second train stimuli elicited almost identical SpMEPs, indicating a quick return of transmission after 50-60 ms considered characteristic of the corticospinal tract rather than the dorsal column, which would have recovered much more slowly. Of the two patients presented, one had no post-operative neurological deteriorations as anticipated by stable SpMEPs, despite otherwise insufficient IONM, and the other developed post-operative motor deficits as predicted by simultaneous reduction of TcMEPs and SpMEPs in the face of normal SEPs. Electrical stimulation of the spinal cord primarily activates the corticospinal tract to mediate SpMEPs.

Economic growth is an emerging issue in Japan because of the declining birthrate, aging population, and declining population of many local Japanese cities. Furthermore, the challenge of lowering the emission of greenhouse gases has become more prominent in the world, and the 2015 Paris Agreement sets reduction targets for each country. Based on these circumstances, city planning that aims for both efficient production activities and low carbon emissions must be conducted to work toward a sustainable society in Japan. In this study, we applied network data envelope analysis (NDEA) to clarify the production efficiency in 47 prefectures of Japan. The sectors are organized into primary, secondary, and tertiary industries, and the transportation industry, which are calculated in decision-making unit (DMU). Considering this classification, each sector is independently evaluated to determine which contributes the most to CO2 emissions, resulting in a detailed production efficiency analysis by transportation capital. The analysis results demonstrate the differences in the measures that should be taken by the prefectures that are deemed less efficient. In addition, comparing the estimation results of the conventional data envelopment analysis (DEA) and NDEA, we reveal the effect of each sector on the fluctuation of DMU’s efficiency value and clarify the reference set for each sector that could not be judged through conventional DEA analysis.

An intraoperative functional spinal cord monitoring system is a technology used by spine and spinal cord surgeons to perform a safe surgery and to gain further surgical proficiency. However, no existing clinical neurophysiological method used in the operating room can monitor all complex spinal cord functions. Therefore, by observing the activities of certain neural action potentials transferred via limited neural tissues, surgeons need to deductively estimate the function of the whole spinal cord. Thus, as the number of spinal cord functions that need to be observed increases, spinal cord monitoring can be more reliable. However, in some situations, critical decision-making is affected by the limited capability of these methods. Nevertheless, good teamwork enables sharing of seamless information within the team composed of a surgeon, anesthesiologist, monitoring technician and nurses greatly contributes to making quick and accurate decisions. The surgeon, who is the person in charge of the team, should communicate with multidisciplinary team members using common technical terms. For this reason, spine and spinal cord surgeons must have appropriate knowledge of the methods currently used, especially of their utility and limitations. To date, at least six electrophysiological methods are available for clinical utilization: three are used to monitor sensory-related tracts, and three are used to monitor motor-related spinal cord functions. If surgeons perform electrode setting, utilizing their expertise, then the range of available methods is broadened, and more meticulous intraoperative functional spinal cord monitoring can be carried out. Furthermore, if the team members share information effectively by utilizing a clinically feasible judicious checklist or tools, then spinal cord monitoring will be more reliable.

Many small and midsized cities around the world are expected to experience rapid shrinking and aging of their populations in the near future. In Japan, these dramatic demographic shifts have already begun in all but the largest cities, creating an urgent need to redesign public transportation systems to accommodate the transit needs of smaller, older populations. Here we focus on the specific case of Takamatsu, a medium-sized city with a population of 420,000 that is currently redesigning its transit system to better serve an aging city with a declining working-age population. We use the agent-based transportation simulation model MATSim to predict the ramifications of Takamatsu’s transit system reforms on transportation behavior in the year 2050. Our analysis reveals how the effects of Takamatsu’s transit reforms vary geographically and temporally, with societal implications—particularly for the mobility of elderly residents—that we discuss.

This paper measures the efficiency of public transport in world cities using three methods: data envelopment analysis, order-α and order-m. We analyze cities’ transport systems and environmental load by calculating the shadow prices of CO 2 emitted from urban transport. We find that efficiencies are lower in several cities in Europe, South Africa, and Western Australia, while they are higher in several cities in India and China. The cities with a high CO 2 shadow price show a slight tendency toward having more efficient public transportation. However, the relationships between the CO 2 shadow price and the efficiency of the public transport system are not clear-cut depending on the applied methods. Several cities without a high CO 2 shadow price may correspond to so-called super-efficient units that can be expressed in the order-m method. We discuss implications to infrastructure and urban transport policies.

Hydrogen as an energy carrier allows the decarbonization of transport, industry, and space heating as well as storage for intermittent renewable energy. The objective of this paper is to assess the future engineering potential for hydrogen and provide insight to areas of research to help lower economic barriers for hydrogen adoption. This assessment was accomplished by creating top-level system models based on energy requirements for end-use services. Those models were used to investigate four case studies that provide a global view augmented with specific national examples. The first case study assesses the potential penetration of hydrogen using a global energy system model. The second applies the dynamic integrated climate–ecosystem–economics model to derive an estimate of the impact of the diffusion of hydrogen as an energy carrier. The third determines the required growth in renewable power and water usage to power transportation in the United States (US) with hydrogen. The fourth assesses the use of hydrogen for heating in the United Kingdom (UK). In all cases, there appeared to be significant potential for hydrogen adoption and net energetic benefit. Globally, hydrogen has the potential to account for approximately 3% of energy consumption by 2050. In the US, using hydrogen for on-road transportation could enable a reduction in rejected energy of nearly 10%. Also, hydrogen might provide the least cost alternative to decarbonizing space heating in the UK. The research highlights a challenge raised by widespread abandonment of nuclear power. It is currently unclear what the removal of nuclear would do to the cost of energy as nations attempt to limit global greenhouse gas emissions. Nuclear power has also been proposed as a source for large scale production of hydrogen. Finally, this analysis shows that with today's technological maturity making the transition to a hydrogen economy would incur significant costs.

Determining the optimal combination of mitigation and adaptation investments is an important topic in policy making to combat climate change. Some analytical results on the relationship between the optimal ratio of adaptation to mitigation and development level have been reported in the literature. In this article, we examine this relationship in greater detail using a simple model with general return functional forms and analytically show that the relationship can take various forms. The results suggest a desirable design of empirical studies on adaptation measures. In addition, the insights obtained in the simple model are useful to understand more complicated models.

Background and aim Nodular gastritis is caused by Helicobacter pylori infection and is associated with the development of diffuse-type gastric cancer. This study examined the clinical characteristics of patients with nodular gastritis, including cancer incidence before and after H. pylori eradication. Methods This was a retrospective study of patients who underwent upper endoscopy and were positive for H. pylori infection. We examined the clinical findings and follow-up data after H. pylori eradication in patients with and without nodular gastritis. Results Of the 674 patients with H. pylori infections, nodular gastritis was observed in 114 (17%). It was more prevalent in women (69%) and young adults. Among patients with nodular gastritis, six (5%) had gastric cancer, all of which were of the diffuse type. Among the 19 (4%) patients with gastric cancer and no nodular gastritis, 16 had intestinal-type cancer. White spot aggregates in the corpus, a specific finding in patients with nodular gastritis, were more frequently observed in patients with gastric cancer than in those without (83% vs 26%, P = 0.0025). Of 82 patients with nodular gastritis who had H. pylori eradicated successfully, none developed gastric cancer over a 3-year follow-up period, while 7 (3%) of 220 patients without nodular gastritis developed gastric cancer after H. pylori eradication. Conclusions In patients with nodular gastritis, white spot aggregates in the corpus may indicate a higher risk of developing diffuse-type gastric cancer. Nodular gastritis may be an indication for eradication therapy to reduce the risk of cancer development after H. pylori eradication.

With the Millennium Development Goal focusing on the eradication of poverty in developing countries expiring in 2015, the international focus is shifting toward sustainable development. The sustainability of the natural resources that are used as energy sources and in the production of goods is a global issue that is not specific to developing nations. We contribute to the need for quantitative targets for natural resources by calculating the shadow prices and production inefficiency levels of 32 mineral resources by using a stochastic frontier analysis and panel data from 1980 to 2010 in 162 countries. In addition, we provide estimated shadow prices and production inefficiency levels up to 2020 with various levels of production restrictions. The results show the following: (1) The shadow prices and production inefficiency levels of major metals are generally higher in Asian countries than in non-Asian countries; (2) there is an upward trend in the inefficiency levels in Asian countries, whereas the inefficiency levels remain rather stable in non-Asian countries; (3) production restrictions do not guarantee an increase in shadow prices, but the magnitude of the impact of such restrictions seems to be larger in Asian countries compared to non-Asian countries; (4) production restrictions do not seem to affect production inefficiency; thus, they may not be effective in reducing gaps in production inefficiency between Asian and non-Asian countries.

The Inclusive Wealth Index (IWI) is a stock-based comprehensive indicator used to evaluate sustainability based on the wealth of nations, including a finer scale that considers the wealth of regions, in which these indicators are required for governance in the administrative regional hierarchies to achieve Sustainable Development Goals. However, few studies have applied the measure to finer-scale wealth relative to the national level. In this paper, we fill the gap by examining the IWI in all prefectures in Japan, where sustainability is increasingly being lost as a result of depopulation, an aging population, and the excessive burden of environmental regulations. We determined that all regions in Japan maintained sustainability from 1991 to 2000. Then, regional sustainability was lost in 8 prefectures from 2001 to 2005 and in 28 prefectures from 2006 to 2010. This trend is consistent with those found in previous studies, though more severe. The decreasing wealth growth is caused by the increasing damage to health capital, mainly in rural areas, whereas produced capital has had positive effects but has not mitigated the damage. Finally, we illustrate how this index can be applied to evaluate projects in response to the intense debate in regional public policy for rural sustainability through a case study of seawalls as a recovery project in the wake of the Great East Japan earthquake.

Background Global warming is the most serious problem we face today. Each country is expected to ensure international cooperation toward minimizing risk. To evaluate the countermeasures, many researchers have developed integrated assessment models (IAMs). Then, how can each country achieve its emission quota? This study proposes models that analyze the economic impact of global warming in a region based on the results obtained by the global model. By using these suggested models, we perform a comparative analysis on three policy cases: a different regulations case, a unified regulation case, and an output redistribution case. Results We analyzed Japan as one of the case studies and found that more developed areas should implement stricter regulations in all scenarios. In addition, the case of applying different regulations by area (in a region) is not always preferable to using unified regulations in the region. Alternatively, the output gap between the output redistribution case and the different regulations case is much higher than the gap between the unified regulation case and the different regulations case. In all scenarios, the present values of the output of the output redistribution case are also higher than the other cases. Conclusions The different regulations case and the unified regulation case are based on the model without capital transfer between areas, whereas the output redistribution case is based on the model with free capital transfer between areas. Although both models are extreme situations, the regions close to the without capital transfer situation possibly have an incentive to use the different regulations policy, depending on the emission target. The regions close to the situation with free capital transfer would probably prefer unified regulation.

Surgical site infection (SSI) after spinal surgery is a devastating complication. Various methods of skin closure are used in spinal surgery, but the optimal skin-closure method remains unclear. A recent report recommended against the use of metal staples for skin closure in orthopedic surgery. 2-Octyl-cyanoacrylate (Dermabond; Ethicon, NJ, USA) has been widely applied for wound closure in various surgeries. In this cohort study, we assessed the rate of SSI in spinal surgery using metal staples and 2-octyl-cyanoacrylate for wound closure.This study enrolled 609 consecutive patients undergoing spinal surgery in our hospital. From April 2007 to March 2010 surgical wounds were closed with metal staples (group 1, n = 294). From April 2010 to February 2012 skin closure was performed using 2-octyl-cyanoacrylate (group 2, n = 315). We assessed the rate of SSI using these two different methods of wound closure. Prospective study of the time and cost evaluation of wound closure was performed between two groups.Patients in the 2-octyl-cyanoacrylate group had more risk factors for SSI than those in the metal-staple group. Nonetheless, eight patients in the metal-staple group compared with none in the 2-octyl-cyanoacrylate group acquired SSIs (p0.01). The closure of the wound in length of 10 cm with 2-octyl-cyanoacrylate could save 28 s and $13.5.This study reveals that in spinal surgery, wound closure using 2-octyl-cyanoacrylate was associated with a lower rate of SSI than wound closure with staples. Moreover, the use of 2-octyl-cyanoacrylate has a more time saving effect and cost-effectiveness than the use of staples in wound closure of 10 cm in length.

Introduction Muscle evoked potentials after electrical stimulation to the spinal cord [Sp(E)-MsEP] are stable and likely to be used for intraoperative spinal cord monitoring. However there is an opinion that Sp(E)-MsEP is not specific for being transferred via the cortico-spinal tract but can also be elicited by stimulation of the dorsal column alone. The aim of this study is to clarify that the spinal motor tract can be monitored by Sp(E)-MsEP. Methods Five consecutive patients (4 women and 1 men), with an average age of 63.4 years (range, 40–74 years), were studied during the surgery of cervical or thoracic spine. We recorded MsEP by three types of stimulation methods (1. transcranial electrical stimulation to the brain, 2.electrical stimulation to the spinal cord, 3. simultaneous stimulation to the brain and spinal cord). 1. transcranial electrical stimulation to the brain: Cork screw type electrodes were inserted symmetrically into the outer table of the skull 5 cm lateral and 2 cm anterior to Cz (International 10–20 system). We used a 5 train stimulation of 2 ms ISI with 0.5 ms duration and 150–200 mA intensity. 2. electrical stimulation to the spinal cord: To stimulate the spinal cord, a catheter electrode was inserted into the epidural space caudal to the level of the lesion. Electrical stimulation was delivered as a 5 train stimulation of 2 ms ISI with 0.2 ms duration and 10–40 mA intensity. Results In all patients at simultaneous stimulation to the brain and spinal cord, the wave form of MsEP from abductor hallucis muscle (AH) was similar of that by spinal cord stimulation. By collision method (simultaneous stimulation of Stim 1 and Stim 2), the wave form of the muscle evoked potential from AH muscle is same of that by not stim 1 but stim 2. It means that the volleys of cortico spinal tract after brain stimulation was collided by the antidromic volley after the stimulation to the spinal cord. In other words, electrical spinal cord stimulation can elicit the volleys travelling through the motor tracts. Conclusion This collision study means that the volleys of cortico spinal tract after brain stimulation was collided by the antidromic volleys after spinal cord stimulation. Therefore we can monitor the motor tracts of the spinal cord using Sp(E)-MsEP.

Objectives The risk of postoperative neurological impairment mandates the use of intraoperative spinal cord monitoring (IOM) during intramedullary spinal cord tumor (IMSCT) surgery. We have used spinal cord evoked potential after electrical stimulation of the cord(Sp-SCEP) to monitor the sensory tract, and SCEP after electrical stimulation to the brain (Br-SCEP) to monitor the motor tract. Both Sp-SCEP and Br-SCEP are stable under general anesthesia. We assessed the clinical utility of these multimodal spinal cord monitoring methods in a retrospective study of a cohort of patients undergoing IMSCT surgery. Methods Thirteen patients with IMSCTs underwent tumor resection using Sp-SCEP and/or Br-SCEP. Results Four patients underwent surgery using only Sp-SCEP monitoring, resulting in two false negatives. Nine patients underwent surgery monitored by Br-SCEP and Sp-SCEP. In three of the nine cases, Br-SCEP amplitude fell by 50% from control levels, despite there being no change in Sp-SCEP. In one of the nine cases, Sp-SCEP amplitude fell to 50% of control levels, but Br-SCEP amplitude was stable. Conclusions During IMSCT surgery, localized regions of the cord may be damaged. Multimodal monitoring should be used to monitor.Combining Sp-SCEP and Br-SCEP is a useful means of monitoring the sensory and motor tracts.

Many materials have been used experimentally as carriers of osteoinductive growth factors. However, there is some doubt about whether the biomechanical strength of the materials affects spinal fusion from early stages of recovery. The aim of this study was to clarify which carrier was biomechanically more effective for bone morphogenetic proteins in spinal fusion. Three biomaterials, each having a different structure and biomechanical strength, were selected as carriers of recombinant human bone morphogenetic protein-2: (1) alpha-tricalcium phosphate cement, which has sufficient biomechanical strength; (2) sintered bovine bone (True Bone Ceramics) coated by type I collagen, which is similar to artificial hydroxyapatite; and (3) type I collagen sheet. Bilateral lumbar intertransverse process arthrodeses were designed in a rabbit model. Spinal fusions were evaluated by radiographic analysis, manual palpation, biomechanics (uniaxial tensile test), and histologic analysis (hematoxylin and eosin, and Villanueva-Goldner's trichrome stains) 3 and 6 weeks after surgery; they were then compared for the three carriers. For achieving the earliest solid spinal fusion, alpha-tricalcium phosphate cement (which has good inherent strength) and True Bone Ceramics (which has good porosity to allow bone penetration) did better than plain collagen (the commonly used carrier).

We studied whether applying nucleus pulposus tissue, obtained from tail intervertebral discs that had been subjected to chronic mechanical compression, to the lumbar nerve roots produces hyperalgesia, which is thought to be a pain-related behavior in the rat. An Ilizarov-type apparatus was used for immobilization and chronically applied compression of the rat tail for eight weeks. Three weeks after application of extracted nucleus pulposus tissue on the lumbar nerve roots, motor function, sensitivity to noxious mechanical stimuli was measured. Eight weeks after application of the apparatus, the instrumented vertebrae were resected and sections were stained with hematoxylin and eosin to evaluate degeneration of the intervertebral disc. Mechanical hyperalgesia observed in rats treated with the compressed nucleus pulposus tissue was greater and of longer duration than in the rats treated with normal and non-compressed discs. The nucleus pulposus in the instrumented vertebrae showed some histological degeneration. In conclusion, chronic mechanical compression of nucleus pulposus, which resulted in degeneration to some extent, enhanced mechanical hyperalgesia, which was induced by application of nucleus pulposus on the nerve root in the rat. Degenerative intervertebral discs might induce more significant pain than normal intervertebral discs.

The current study is a biomechanical study using a cadaveric model of L5-S1 spondylolisthesis. The purpose of the current study was to compare, in a cadaveric model of simulated L5-S1 spondylolisthesis, the biomechanical stiffness of transdiscal fixation with traditional pedicle screw fixation, and transdiscal fixation with combined interbody/pedicle screw fixation. The surgical management of L5-S1 spondylolisthesis is a challenge because of the difficulties in achieving a reliable arthrodesis in the face of high mechanical forces. A method of lumbosacral fixation that has been used successfully in moderate grades of spondylolisthesis at our institution involves the use of transdiscal S1 pedicle screws. With this technique, S1 pedicle screws are placed through the S1 pedicle, through the superior endplate of S1, through the inferior endplate of L5, to terminate in the L5 body. Eighteen fresh human cadaveric (age 59-88 years) L5-S1 motion segments were obtained. The end of each intact motion segment was potted up to its midbody in a 10-cm-diameter polyvinylchloride end-cap using dental cement. The intact specimen was then biomechanically tested as follows: 1) axial compression (500 N), 2) flexion (10 Nm), 3) extension (10 Nm), 4) right lateral bending (10 Nm), and 5) left lateral bending (10 Nm). Stiffness values were calculated from the load-deflection curves obtained. Spondylolisthesis was then simulated by displacing L5 on S1 (% slip average = 41.3%) after performing a radical L5-S1 discectomy, L5 laminectomy, and bilateral L5-S1 facetectomies. The 18 motion segments were divided into two groups. Group I (n = 10) was biomechanically tested (as above) after pedicle screw fixation and again after replacing the S1 pedicle screws with transdiscal screws. Group II (n = 8) was biomechanically tested (as above) after combined interbody/pedicle screw fixation and again after fixation with transdiscal screws. Load-deflection curves were obtained each time, and stiffness values were calculated from the curves. Transdiscal fixation was 1.6-1.8 times stiffer than pedicle screw fixation (p < 0.05) in all loading modes tested. There were no differences in stiffness between transdiscal fixation and combined interbody/pedicle screw fixation. In a cadaveric model of simulated L5-S1 spondylolisthesis, transdiscal L5-S1 fixation produced a 1.6-1.8 times stiffer construct than traditional pedicle screw fixation. Further, the stiffness of the transdiscal fixation was equal to that of a combined interbody/pedicle screw fixation.

Study design A clinical case using a new surgical technique is reported. Objective To report for the first time an endoscopically assisted anterior screw fixation for the Type II odontoid fracture. Summary of background data Recently, many endoscopically assisted surgeries have been performed for various spinal surgery because of its minimally invasive character. However, the anterior retropharyngeal approach to the upper cervical spine using endoscopy has not been reported. Methods A 76-year-old man was operatively managed for a Type II odontoid fracture. The operation was performed under immobilization of cervical spine using a halo vest apparatus. A skin incision 2 cm long was made on the medial border of the right sternocleidomastoid muscle at the C5-C6 intervertebral level. Blunt dissection between the neurovascular bundle laterally and the trachea and esophagus medially was performed. A processed polyethylene syringe (volume, 10 mL) was used as the tubular retractor. This retractor kept the minimum but sufficient space for the screw fixation and avoided esophageal complication. Using a cannulated screw system, a cancellous screw was inserted from the anteroinferior edge of the C2 vertebral body to the tip of the odontoid process. The drilling and the screwing process was monitored by a two-dimensional image intensifier. The entry point was monitored by endoscopy to avoid soft tissue involvement as well. Results The operation was completed without any soft tissue complications such as esophageal injury. The blood loss was 30 mL. The procedure resulted in nonunion, partially because of patient's old age or an entry point 2 mm above the anterior caudal margin of the C2 body retrospectively. Conclusions Although the reported odontoid fracture ended in nonunion, the authors believe their modification of the approach using an endoscope made anterior screw fixation for the odontoid fracture safer and less invasive than the original anterior retropharyngeal approach.

A 53-year-old male underwent more than 10 surgical treatments over 14 years, including a simple excision and local flap transfer, after recurrences of dermatofibrosarcoma protuberans of the head. Clinical results indicated that simple excision of dermatofibrosarcoma protuberans should not be performed as initial treatment. Instead, free flap transplantation, which permits a wide excision and complete reconstruction, should be the first treatment option.

A total of 103 patients with cervical spondylotic myelopathy undergoing laminoplasty were retrospectively reviewed to evaluate whether sagittal alignment of the cervical spine and morphology of the spinal cord influence surgical outcomes. Sagittal alignment of the cervical spine did not influence surgical outcomes. Neurologic recovery in patients with anterior convexity of the spinal cord was better than in those without this type of spinal cord. In patients with supplementation of decompression at C2, sagittal morphology of the spinal cord did not influence neurologic recovery. It is important to acquire anterior convexity of the spinal cord after surgery if laminoplasty is performed below C3. In patients with kyphosis, where anterior convexity of the spinal cord is not thought to be obtained postoperatively, it is possible that additional decompression of C2 improves outcome.

Sixty-seven patients with cervical spondylotic myelopathy treated with expansive laminoplasty were retrospectively reviewed at a minimum 2-year follow-up. This study was designed to evaluate whether preoperative instability influences the clinical outcome in patients with cervical spondylotic myelopathy treated with laminoplasty without spinal fusion. Patients with preoperative instability were older and had shorter durations of symptoms prior to surgery than those without the instability. There were no significant differences in prevalence of axial symptoms, neurologic recovery, or radiologic findings between patients with and without preoperative cervical instability. At follow-up, the cervical range of motion was limited to 43.5% of the preoperative range, and no cervical instability was observed in any patients. Preoperative instability does not influence the clinical outcome and can be ignored if expansive laminoplasty is indicated for patients with cervical spondylotic myelopathy.

We examined the relationship between decreases in the amplitude of the compound muscle action potential (CMAP), caused by ischemic and compressive insults to the spinal cord, and postoperative motor deficits. Results were compared with those for other evoked potentials commonly used for multimodal monitoring of the spinal cord. CMAP was more sensitive than the other evoked potentials employed to ischemic and compressive insults to the spinal cord, although the disappearance of CMAP did not always result in a residual motor deficit. A decrease of more than 50% in the amplitude of the motor-evoked potential (MEP) from the spinal cord correlated well with the postoperative motor deficit. CMAP is a sensitive tool for the early detection of spinal cord impairment caused by ischemic or compressive insults to the spinal cord. The time after the disappearance of the CMAP amplitude was important for predicting postoperative motor deficit, but it is also necessary to employ CMAP concomitantly with other conductive potentials in spinal cord monitoring.

Study design This is a case report of a patient with hypertrophy of the posterior longitudinal ligament (HPLL) in the lumbar spine, with assessment of operative treatment and a 10-year follow-up using magnetic resonance imaging. Objectives To report on the long-term outcome of a case of lumbar HPLL, to review the literature on case reports of HPLL, and to outline the pathology of HPLL in the lumbar spine. Summary of background data There have been several reports of HPLL in the cervical spine and thoracic spine. However, the authors found no reports of this condition in the lumbar spine and no reports of long-term follow-up. Two types of pathology are associated with HPLL: primary hypertrophy of the ligament and secondary hypertrophy associated with intervertebral disc herniation. Methods A 10-year follow-up evaluation of a 56-year-old man with HPLL at L2 is reported. The patient was observed using serial physical examinations, radiographs, and MRIs over 10 years. Because he did not respond to conservative management, surgical treatment was applied. After complete decompression by hemilaminectomy and resection of hypertrophied ligament, the nerve roots were freed of constriction through the neural foramens at L2 and L3. Results One year after the operation the patient was asymptomatic without evidence of recurrence of the disease. Conclusions HPLL is a very rare disease. This appears to be the first report of the disease in the lumbar spine.

Biologically active substances, such as prostaglandins, thromboxanes, and leukotrienes, which are metabolites involved in the arachidonic acid cascade, are detected in herniated disc samples obtained from patients with lumbar disc herniation. However, little is known concerning the relationships between these substances and clinical symptoms such as radicular pain. Thromboxane A2 (TXA2) induces not only potent platelet aggregation, but also blood vessel contraction. Leukotriene B4 (LTB4), a potent chemotactic agent, plays a role in inflammatory reactions by recruiting neutrophils and lymphocytes. The purpose of this study was to examine the roles of TXA2 and LTB4 in the hyperalgesia induced by application of nucleus pulposus to the lumbar nerve root in the rat. TXA2 synthetase inhibitor and LTB4 receptor antagonist, which were injected into the epidural space, decreased mechanical hyperalgesia at both three and seven days after epidural injection. There were no significant differences in sensitivity to noxious thermal stimuli following application of the nucleus pulposus or an epidural injection. Epidural injection of LTB4 receptor antagonist and/or TXA2 synthetase inhibitor may attenuate the painful radiculopathy due to lumbar disc herniation. In conclusion, our findings suggest that TXA2 and LTB4 may play significant roles in mechanical hyperalgesia induced by autologous nucleus pulposus.

STUDY DESIGN Posterolateral lumbar transverse process fusion in a rabbit model was performed using two different carriers for recombinant human morphogenetic protein-2, one having a porous structure and the other being a Type I collagen sheet. OBJECTIVES To compare the effectiveness of two different carriers for recombinant human morphogenetic protein-2 in achieving lumbar intertransverse process arthrodesis. SUMMARY OF BACKGROUND DATA The application of osteoinductive growth factors at various anatomic sites, such as in long bones and spinal segments, has been performed experimentally by many researchers. Although many carriers of osteoinductive factors have been reported, the most effective carrier has not been established. We have reported the efficacy of sintered bovine bone, True Bone Ceramics, which is coated with Type I collagen as a carrier of recombinant human bone morphogenetic protein-2 in achieving lumbar intertransverse process arthrodesis. True Bone Ceramics is a crystallized form of bone minerals made from sintering bovine bone at high temperatures and possesses natural trabecular structure. The crystalline character of True Bone Ceramics is similar to that of artificial hydroxyapatite. In this study we focused on the structure of two different carriers to facilitate osteosynthesis in lumbar arthrodesis. METHODS Fifty-four adult rabbits underwent bilateral lumbar intertransverse process arthrodesis at L4-L5. The animals were divided into five groups and had implants placed as follows: Group 1, autograft group, harvested autologous corticocancellous bone from the posterior iliac crest; Group 2, TBC group, True Bone Ceramics alone; Group 3, TBC-TBMP group, True Bone Ceramics coated with Type I collagen infiltrated with 100 microg of recombinant human bone morphogenetic protein-2; Group 4, collagen group, Type I collagen sheet; and Group 5, collagen-BMP group, implanted collagen sheet containing 100 microg of recombinant human bone morphogenetic protein-2. Spinal fusion was evaluated by radiographic analysis, manual palpation, biomechanical testing, and histologic examination at both 3 and 6 weeks after surgery. RESULTS Radiographs in the TBC-TBMP group showed a continuous trabecular pattern within the intertransverse area at 3 weeks after surgery. The fusion mass in the intertransverse area was more prominent than in the other groups. At 3 weeks after surgery the TBC-TBMP group had higher fusion rates based on manual palpation, and the fusions showed significantly higher tensile strength and stiffness. The histologic findings in the TBC-TBMP group at 3 weeks after surgery showed a cortical bone rim around the edge of the fusion mass, and contiguous new bone appearing between the recipient bone and the matrix of TBC without evidence of foreign body formation. In the collagen-BMP group, less mature bone formation was present within the grafted area and the new bone was not contiguous, even at 6 weeks after surgery. CONCLUSIONS As a carrier for recombinant human bone morphogenetic protein-2, True Bone Ceramics, possessing a bony or porous structure, was more effective than a Type I collagen sheet in achieving a faster and stronger lumbar spinal fusion in a rabbit model.

Some studies have assessed inflammatory cells such as macrophages, lymphocytes, and neutrophils in herniated lumbar disc tissues using histologic analysis. However, there is no consensus regarding the relationships between clinical symptoms, including radicular pain and the presence of inflammatory cells. It has been shown that autologous nucleus pulposus relocated on the lumbar nerve root in rats produces time dependent and reversible mechanical hyperalgesia, which is thought to be a pain related behavior in peripheral neuropathic pain models. The purpose of this study was to determine whether leukocytes play a role in the mechanical hyperalgesia induced by the nucleus pulposus and to characterize the role of leukocytes in radicular pain attributable to lumbar disc herniation. Nitrogen mustard was used to induce and evaluate leukocytopenia in rats. Sensitivity to mechanical noxious stimuli was measured quantitatively, and inflammatory cells in granulation tissue around the nerve root were examined histologically. The nucleus pulposus produced neither mechanical hyperalgesia nor abundant inflammatory cells in rats with nitrogen mustard induced leukocytopenia. Neuropathic pain produced by the nucleus pulposus, when placed on the nerve root, may be related to inflammatory cell infiltration induced by relocation of the nucleus pulposus, rather than the nucleus pulposus itself.

In this communication, we demonstrate the sequential expression of endogenous molecules, including immediate early genes (IEGs), cytokines, neurotrophins, and neurotrophin receptors in the injured spinal cord. In the acute phase, expression of IEGs and cytokines mRNAs were rapidly upregulated within 1 h in nonneuronal cells in the lesioned sites and the surrounding spinal white and gray matter. Maximal expression was observed at 1 h for c-fos and TNF-alpha mRNAs, at 3 h for c-jun and IL-6 mRNAs, and at 6 h for IL-1 beta mRNA, and these signals were virtually nondetectable after 6-12 h from the onset of the injury. Some of these genes products may promote the degeneration of damaged cells and tissues, while others may be involved in the subsequent repair processes. In the subacute phase, expression of NGF, BDNF, NT-3, p75LNGFR and Trk B mRNAs began to increase in the nonneuronal cells and neuronal cells from 6 h, and peaked at 24-72 h in the area where expression of mRNAs for IEGs and cytokines overlapped. Signals for IL-6 mRNA were also observed in motoneurons at 24-72 h after the injury, with the suggestion that these molecules may be involved in promoting axonal sprouting in the injured spinal cord. Of further interest was the finding that this upregulation of IL-1 beta, BDNF, and NT-3 mRNAs in injured spinal cord was attenuated by treatment with high dose glucocorticoids, with the suggestion that the downregulation of BDNF and NT-3 might be disadvantageous to survival and axonal sprouting of spinal neurons.

The purpose of this study was to refine a method of nerve-root injury in the rat to produce hyperalgesia, a pain-related behavior, and to determine if there were any relationships between the histological extent of nerve-root injury and the magnitude of hyperalgesia. Three methods were used to produce hyperalgesia: irritation of a nerve root by ectopic nucleus pulposus, silk loop alone, or both silk loop and ectopic nucleus pulposus. Autologous nucleus pulposus obtained from coccygeal intervertebral discs was relocated on the lumbar nerve roots after laminectomy. Two loops of 4-0 silk were placed around the exposed nerve roots. Hyperalgesia was measured preoperatively and postoperatively. The distribution of myelinated axons in the dorsal nerve roots was evaluated histologically. Mechanical hyperalgesia was detected in rats in which autologous nucleus pulposus was applied to the nerve root but not in those in which silk loops were used. Silk loops around the nerve root resulted in thermal hyperalgesia only in rats in which autologous nucleus pulposus was applied to the nerve root. Fewer large myelinated fibers were seen in the rats in which silk loops were used. Although a silk loop around the nerve root was not sufficient to produce hyperalgesia, supplemental application of autologous nucleus pulposus to the nerve root produced thermal hyperalgesia. It is possible that mechanical constriction of the nerve root alters the pain-related behavior elicited by chemical factors from the nucleus pulposus.

The purpose of this study was to examine whether mRNA of interleukin-A2, interleukin-6, phospholipase A2, and nitric oxide synthase was expressed in the nerve root and dorsal root ganglion of an animal model in which exposure to the nucleus pulposus induced mechanical hyperalgesia, a pain-related behavior. Autologous nucleus pulposus obtained from coccygeal discs was relocated on the L4 and L5 lumbar nerve roots after partial laminectomy. The reflex response to noxious mechanical stimuli to the hindpaw was measured preoperatively and to 4 weeks postoperatively. With a reverse transcription-polymerase chain reaction technique, expression of interleukin-1beta, interleukin-6, phospholipase A2, and inducible nitric oxide synthase genes in the nerve root and dorsal root ganglion was observed at 1, 2, and 4 weeks postoperatively. Mechanical hyperalgesia was observed from 3 days to 2 weeks postoperatively. The expression of interleukin-1beta, phospholipase A2, and inducible nitric oxide synthase mRNAs increased after only 1 week. This increase was related to mechanical hyperalgesia. Expression of interleukin-6 was detected in the neural tissue over time. It is possible that interleukin-1beta, phospholipase A2, and inducible nitric oxide in the nerve root or dorsal root ganglion, or in both, produce sciatic pain in the early stage of herniation of the lumbar disc.

Study Design. The outcome of a herniated disc in patients with cervical myelopathy treated by laminoplasty without discectomy and in those treated conservatively was studied by magnetic resonance imaging. Objectives. To compare the surgical results of laminoplasty with those of anterior spinal fusion in patients with myelopathy caused by to cervical disc herniation and to make a treatment strategy for cervical disc herniation depending on these results. of Background Data. Anterior discectomy and spinal fusion have had acceptable surgical results, but many complications have been reported, especially adjacent segment degeneration and bone graft complications. Methods. Forty-seven patients with cervical disc herniation were examined in this study. Of them, 32 patients (mean age, 56 years) underwent laminoplasty without resection of the herniated disc. Seven patients with mild cervical myelopathy and 8 patients with radiculopathy (mean age, 53 years) were treated conservatively. As a control group, 44 patients (mean age, 50.3 years) who underwent anterior spinal fusion were examined. All patients in the laminoplasty group also had congenital spinal canal stenosis in which the ventrodorsal canal diameter was less than 13 mm. The association between the outcome of a herniated disc and clinical features was investigated. The severity of myelopathy was evaluated according to the Japanese Orthopaedic Association's scoring system. Surgical outcomes were evaluated by the system of Hirabayashi for determining recovery rate. Results. The recovery rate averaged 67.9% in laminoplasty and 68.8% in anterior spinal fusion. There were no significant differences between the groups. No patients underwent anterior spinal fusion after laminoplasty. Follow-up magnetic resonance imaging showed regression of the size of the herniated disc in 15 of the 20 patients in the laminoplasty group and in 12 of 15 patients treated conservatively. In the MRI studies of the natural course of disc herniation, the size of the herniated disc decreased to almost half in 1 to 2 months and almost disappeared within 3 months after surgery. Conclusions. The size of the herniated disc in cervical lesions regressed as it does in the lumbar lesions. Laminoplasty for patients with narrowed spinal canals showed favorable surgical results. Therefore, the therapeutic method for cervical disc herniation should be chosen after taking the natural history of the disc herniation into consideration.

The aim of this study was to retrospectively review clinical outcomes of posterolateral fusion for 50 consecutive patients with unstable lumbar spine and to determine which radiological factors affect clinical results. Patients with poor outcomes were older and had a greater number of fused segments than did those with good outcomes. Except for these, there were no relationships between clinical preoperative factors and outcomes on follow-up examination. At follow-up, decrease in lordosis and increases in slippage and L1 axis S1 distance (LASD) (which was measured as the distance along the perpendicular axis from the center in the L1 body to the posterior superior edge of the S1 body) were found in patients with poor surgical outcomes. The slippage on follow-up examination was significantly greater in patients with LASDs above 35 mm, preoperatively, than in those whose LASD was less than 35 mm. The lesions of adjacent segments and bony union rate did not influence the clinical results. A preoperative radiological risk factor is LASD greater than 35 mm, which was associated with an increase in the slippage at follow-up. Maintenance of lumbar lordosis and an LASD below 35 mm and after the surgery, may improve clinical outcomes.

A universal inhibitor of cyclin‐dependent kinases, WAF1/Cip1 can dephosphorylate the RB gene product to arrest the cell cycle at the G1 phase. Here we show that the mRNA level and the promoter activities of the RB and WAF1/Cip1 genes exhibit cell cycle‐dependent change when cells are released from either serum‐starvation or the confluent cell state with serum. RB expression and promoter activity are elevated at middle to late G1. In contrast, the mRNA and promoter activity of the WAF1/Cip1 gene increase at early G1. These results suggest that the RB and WAF1/Cip1 expression and promoter activities depend not only on serum, but also on the cell cycle progression itself. Moreover, we identified the responsive region for serum‐released cell cycle progression in the RB promoter and mapped it to the region between –4 and –182 relative to the initiating codon of the RB gene. The region in the WAF1/Cip1 promoter responsible for the serum‐released cell cycle progression mapped not to the p53 binding site, but to the 374 base‐pair region between –1770 and –1396 from the transcription start site.

A study was conducted to determine the effect of radiographic findings of lumbar spinal changes upon bone mineral density measurements obtained by dual energy X-ray absorptiometry (DXA). Four hundred subjects were chosen from among 1543 community residents, aged 40–79 years. Study groups of 50 subjects each were selected by sex and 10-year age groups. This study investigated 390 of the 400 subjects who agreed to the conduct of spine bone mineral density measurement and spinal radiography. Lumbar spine radiograms were examined for findings of osteophyte formation, facet joint osteoarthritis, vertebral fracture, and aortic calcification. The prevalence of osteophyte formation, facet joint osteoarthritis, vertebral fracture, and aortic calcification increased with age in both men and women. On multiple regression analysis, bone mineral density was significantly higher (P < 0.001) in subjects with osteophyte formation or facet joint osteoarthritis than in those without these conditions, while bone mineral density was significantly lower in subjects with vertebral fracture. This study demonstrated that osteophyte formation, facet joint osteoarthritis, and vertebral fracture should be taken into account in the evaluation of bone mineral density by DXA in people in older age groups, since these conditions occur at a considerable rate in such subjects.