Radiographic changes in patients with pseudarthrosis after posterior lumbar interbody arthrodesis using carbon interbody cages: a prospective five-year study

BACKGROUND

The aim of this study was to demonstrate longitudinal radiographic changes at up to five years in patients with pseudarthrosis after posterior lumbar interbody arthrodesis using carbon interbody cages.

METHODS

From 2003 to 2006, prospective longitudinal radiographic and CT (computed tomography) scan evaluations were made at up to five years after posterior lumbar interbody arthrodesis using carbon interbody cages at one or two levels in 153 consecutive patients. At the one-year evaluation, seventeen patients with early pseudarthrosis at nineteen levels were selected as subjects on the basis of one or more of the following characteristics: complete absence of osseous bridging between the upper and lower vertebrae, angular motion of ≥5°, and/or radiolucent zones surrounding the implant. Angular motion, continuity of osseous bridging, grafted bone quantity, and radiolucent zones around the pedicle screws and cages were observed annually until five years.

RESULTS

The mean angular motion of five levels that exhibited ≥5° of motion at one year began to decrease significantly thereafter (p = 0.046), and no level showed movement of ≥5° at five years. The mean grade of the radiolucent zones around the screws on CT showed significant improvements at two years (p = 0.039) and three years (p < 0.01). The radiolucent zones around the screws disappeared at twelve of sixteen levels by five years, and the radiolucent zones around the cages disappeared in eleven of seventeen levels by five years. Of eighteen levels with early pseudarthrosis, seven (39%) were assessed as successfully fused at three years and twelve (67%) at five years. Four (80%) of five patients with a radiolucent zone of >1 mm around the entire cage on CT at one year showed continuing pseudarthrosis at five years, whereas only two (15%) of thirteen patients without this finding did (crude relative risk = 5.2; 95% confidence interval, 1.35 to 20.02). A radiolucent zone of >1 mm around the entire cage on CT at one year could be an early predictor of permanent pseudarthrosis (odds ratio = 123; 95% confidence interval, 1.03 to 14,680).

CONCLUSIONS

The interbody arthrodesis site in patients with early pseudarthrosis may begin to change to a successful fusion one or two years after surgery, with two-thirds of such patients exhibiting successful fusion five years after surgery. Final assessment of pseudarthrosis should be performed at least three years after surgery. A radiolucent zone of >1 mm around the entire interbody cage on CT at one year may require early additional surgery.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Olanzapine increases hepatic glucose production through the activation of hypothalamic adenosine 5'-monophosphate-activated protein kinase

AIMS

To investigate the mechanism of the metabolic disturbance induced by the atypical antipsychotic olanzapine, we examined whether adenosine 5'-monophosphate-activated protein kinase (AMPK) in the hypothalamus and hepatic glucose production are involved in the effect of olanzapine.

METHODS

Male 6-week-old ICR mice were used. Blood glucose levels were determined by the glucose oxidase method. The mRNA levels of gluconeogenic or glycolytic enzymes were measured by reverse transcription polymerase chain reaction (RT-PCR). AMPK expression was measured by Western blotting.

RESULTS

Systemic injection of olanzapine increased blood glucose levels in both unfasted and fasted mice. However, the increase in fasted mice was less than that in unfasted mice. Central administration of olanzapine also increased the blood glucose levels in unfasted mice, but not in fasted mice. In a pyruvate tolerance test, olanzapine significantly increased blood glucose levels. In addition, olanzapine increased the mRNA levels of glucose-6-phosphatase (G6Pase), a gluconeogenic enzyme, in the liver. Furthermore, olanzapine increased phosphorylated AMPK in the hypothalamus of unfasted mice, and olanzapine-induced hyperglycaemia was inhibited by the AMPK inhibitor compound C. Central administration of the AMPK activator AICAR significantly increased G6Pase mRNA levels in the liver and blood glucose levels. Moreover, both olanzapine- and AICAR-induced hyperglycaemia were attenuated by the β-adrenergic receptor antagonist propranolol, suggesting that olanzapine and AICAR induce hepatic glucose production through the sympathetic nervous system.

CONCLUSIONS

Our results indicate that olanzapine activates AMPK in the hypothalamus, which increases hepatic glucose production via the sympathetic nervous system.

The effects of surgery on locomotion in elderly patients with cervical spondylotic myelopathy

PURPOSE

This study aimed to evaluate the effects of surgery on locomotor ability in patients with cervical spondylotic myelopathy (CSM) and compare the results between elderly and younger patients.

METHODS

A total of 369 consecutive patients who underwent expansive laminoplasty for CSM were prospectively analysed. Patients were divided into two age groups of ≥ 75 years (elderly group, 76 patients) and <75 years (younger group, 293 patients). Locomotor ability was estimated using part of the functional independence measure (FIM). The sum of gait and stairs items [functional independence measure (locomotion), FIM-L; possible scores, 2-14] and neurological status were estimated using the Japanese Orthopaedic Association (JOA) score (possible score, 0-17). Pre-operative neurological anamnesis was reviewed, and the surgical results of elderly patients with or without co-existing neurological history were evaluated to determine the origin of locomotor disability.

RESULTS

Peri-operative FIM-L and JOA scores were significantly lower in the elderly group than in the younger group, and the opposite was true for improved FIM score. Cerebral infarction and previous lumbar surgery were identified as neurological co-morbidities in the elderly group. However, there was no significant difference in surgical results between elderly patients with and without co-existing neurological disorders.

CONCLUSIONS

Decompression surgery can improve locomotor ability and decrease nursing care requirements among elderly patients with CSM. However, other neurological diseases can co-exist in elderly patients, making it difficult to diagnose the origin of locomotor disability. Therefore, detailed peri-operative work-up and timely decompression should be given priority to avoid progression towards fixed locomotor disability.

Local bandgap control of germanium by silicon nitride stressor

We have proposed a new approach to tune the operation wavelength of Franz-Keldysh Ge electro-absorption modulation in Si photonics by controlling the local strain environment to cover the whole range of C + L bands (1.53 - 1.62 μm). The present paper shows a proof of strain-tuning modulator concept by the shift of the Ge absorption edge using SiN(x) stressor films and Franz-Keldysh effect in strain-controlled Ge.

Flow cytometry as a diagnostic method for colorectal cancer

Intraoperative histopathological investigation plays an important role during surgery. Since the pathologist performs a diagnosis with a limited level of specimen, it may sometimes be difficult to reach a correct diagnosis. To improve the accuracy of the diagnosis, quantitative data from the whole specimen are helpful. It said that the detection capability for DNA aneuploidy (aneuploidy) is low for solid cancer compared with hematopoietic organ cancer. A new method that includes fresh tissue is introduced, the histogram from cancer tissue (cancer) and normal tissue (normal) is compared, new classification criteria are introduced, the Fast Fourier Transform (FFT) pattern (FFT pattern) obtained from FFT on the histogram is analyzed, and the area under the FFT pattern of the histogram (AUC) is compared. This method, named the "FFT-AUC method", which includes comparisons of AUC and the FFT pattern, shows good results.

New automatic cell isolation system for flow cytometry: cell isolation unit and staining reagent kit

Flow cytometry is well-known cell analysis method and useful to gain quantitative information from cells in blood, however, it is not widely used for solid tissues in clinical settings. This is partly because it takes a long time to prepare samples and the operation can be complicated. To resolve these problems, we developed a new automatic cell isolation system which consists of cell isolation unit and staining reagent kit specialized for flow cytometry. With this new system, cell isolation can be done more rapidly and easily. By using this method, we could determine optimum condition to disintegrate porcine colon tissue and stain cells stably in 6 minutes. This result indicates that our method can provide analysis data within 10 minutes. We also evaluated our method in colorectal cancer patients, and the result was promising. All the data suggests that this method can support and facilitate rapid diagnosis.

Werner syndrome: a changing pattern of clinical manifestations in Japan (1917~2008)

As ~75% of the Werner syndrome (WS) patients recognized between 1904 and 2008 all over the world are of Japanese origin, the most case reports and clinical studies on WS has been published in Japanese journals. Thus, the detailed English-written clinical review on the recent WS case reports has been warranted. Although WS has been characterized by a variety of clinical manifestations mimicking premature aging, the recent longevity and delayed age-associated manifestations observed both from Japanese WS and general population may suggest a common environmental effect on some gene(s) other than WRN and may give us a newer pathophysiological look at WS and also natural aging through the molecular dysfunction of WRN.

An in vitro demonstration of CMOS-based optoelectronic neural interface device for optogenetics

A CMOS-based neural interface device equipped with an integrated micro light source array for optogenetics was fabricated and demonstrated. A GaInN LED array formed on sapphire substrate was successfully assembled with a multifunctional CMOS image sensor that is capable of on-chip current injection. We demonstrated a functionality of light stimulation onto ChR2-expressed cells in an in vitro experiment. A ChR2-expressed cell were successfully stimulated with the light emitted from the fabricated device.

High-dose zoledronic acid narrows the periodontal space in rats

The aim of this experiment was to evaluate the histological effects of zoledronic acid on the periodontal space in rats. 40 male Wistar rats were divided into three zoledronic acid groups and a control group. Zoledronic acid was injected subcutaneously at doses of 10, 50, or 500 μg/kg once a week for 3 weeks. The rats were killed 1 or 9 weeks after the last injection. Histological examination of the periodontal space around the incisor tooth revealed that zoledronic acid did not inhibit tooth development. In the rats killed 1 week after treatment discontinuation, the periodontal space gradually narrowed in response to increasing zoledronic acid doses, and the changes were statistically significant according to ANOVA but not according to ANOVA with post hoc tests. The changes persisted in the high-dose zoledronic acid group despite zoledronic acid discontinuation, with significant differences identified by ANOVA and ANOVA with post hoc tests. Therefore, although zoledronic acid had an insignificant effect on tooth development, it had a significant effect on the periodontal space when high doses were administered. The results of this experiment may provide useful information for future investigations on the role of zoledronic acid in the osteonecrosis of the jaw.

Multivariate analysis of C-5 palsy incidence after cervical posterior fusion with instrumentation

Object

Postoperative C-5 palsy is a significant complication resulting from cervical decompression procedures. Moreover, when cervical degenerative diseases are treated with a combination of decompression and posterior instrumented fusion, patients are at increased risk for C-5 palsy. However, the clinical and radiological features of this condition remain unclear. Therefore, the purpose of this study was to clarify the risk factors for developing postoperative C-5 palsy.

Methods

Eighty-four patients (mean age 60.1 years) who had undergone posterior instrumented fusion using cervical pedicle screws to treat nontraumatic lesions were independently reviewed. The authors analyzed the medical records of some of these patients who developed postoperative C-5 palsy, paying particular attention to their plain radiographs, MRI studies, and CT scans. Risk factors for postoperative C-5 palsy were assessed using multivariate logistic regression analysis. The cutoff values for the pre- and postoperative width of the intervertebral foramen (C4–5) were determined by receiver operating characteristic curve analysis.

Results

Ten (11.9%) of 84 patients developed postoperative C-5 palsy. Seven patients recovered fully from the neurological complications. The pre- and postoperative C4–5 angles showed significant kyphosis in the C-5 palsy group. The pre- and postoperative diameters of the C4–5 foramen on the palsy side were significantly smaller than those on the opposite side in the C-5 palsy group and those bilaterally in the non–C5 palsy group. Risk factors identified by multivariate logistic regression analysis were as follows: 1) ossification of the posterior longitudinal ligament (relative risk [RR] 7.22 [95% CI 1.03–50.55]); 2) posterior shift of the spinal cord (C4–5) (RR 1.73 [95% CI 1.00–2.98]); and 3) postoperative width of the C-5 intervertebral foramen (RR 0.33 [95% CI 0.14–0.79]). The cutoff values of the pre- and postoperative widths of the C-5 intervertebral foramen for C-5 palsy were 2.2 and 2.3 mm, respectively.

Conclusions

Patients with preoperative foraminal stenosis, posterior shift of the spinal cord, and additional iatrogenic foraminal stenosis due to cervical alignment correction were more likely to develop postoperative C-5 palsy after posterior instrumentation with fusion. Prophylactic foraminotomy at C4–5 might be useful when preoperative foraminal stenosis is present on CT. Furthermore, it might be useful for treating postoperative C-5 palsy. To prevent excessive posterior shift of the spinal cord, the authors recommend that appropriate kyphosis reduction should be considered carefully.