Lower preoperative Hounsfield unit values as a risk factor for poor 5-year clinical outcomes after lumbar spine surgery.

OBJECTIVE: Hounsfield Unit (HU) value has been associated with future osteoporotic fractures and postoperative complications. However, no studies on the impact of low HU values on mid-term clinical outcomes following lumbar spine surgery have been reported. We aimed to evaluate the usefulness of preoperative HU values for 5-year clinical outcomes following lumbar spine surgery. METHODS: We enrolled 200 patients who underwent lumbar surgery (≤ 3-disc levels) for lumbar spinal stenosis. HU values were assessed using preoperative lumbar computed tomography as part of routine preoperative planning for lumbar surgery. Patients were divided into two groups based on the cutoff value of the HU values obtained from the receiver operating characteristic curve for the incidence of vertebral fractures within five years postoperatively. Clinical scores preoperatively and 1, 2, and 5 years postoperatively, including Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and Short Form-36 (SF-36), were compared using a mixed-effects model. RESULTS: Comparative analysis indicated that all domains of JOABPEQ, except for lumbar function, and the physical component summary of the SF-36 were significantly worse in the low HU group than in the high HU group. Using multiple regression analysis, low HU values were significantly correlated with worse 5-year postoperative scores in all domains of JOABPEQ and SF-36. CONCLUSION: Low preoperative HU values are a risk factor for poor 5-year clinical outcomes after lumbar spine surgery. HU values are not only a valuable tool for analyzing bone mineral density but also may be a valuable poor prognostic factor of postoperative clinical outcomes.

Ventricular fold oscillations lower the vocal pitch in rhesus macaques.

We carried out ex vivo and in vivo experiments to explore the functional role of the ventricular folds in sound production in macaques. In the ex vivo experiments, 29 recordings out of 67 showed that the ventricular folds co-oscillated with the vocal folds. Transitions from normal vocal fold oscillations to vocal-ventricular fold co-oscillations as well as chaotic irregular oscillations were also observed. The in vivo experiments indicated that the vocal-ventricular fold co-oscillations were also observed in two macaque individuals. In both ex vivo and in vivo experiments, the vocal-ventricular fold co-oscillations significantly lowered the fundamental frequency. A mathematical model revealed that the lowering of the fundamental frequency was caused by a low oscillation frequency inherent in the ventricular folds, which entrained the vocal folds to their low-frequency oscillations. From a physiological standpoint, the macaques may utilize the ventricular fold oscillations more frequently than humans. The advantages as well as disadvantages of using the ventricular folds as an additional vocal repertory are discussed.

A comparison of axial trunk rotation during bipedal walking between humans and Japanese macaques.

OBJECTIVES: Human walking involves out-of-phase axial rotations of the thorax and pelvis. It has long been believed that this rotational capability is a distinctive feature of the genus Homo. However, Thompson et al. (2015) showed that chimpanzees also counter-rotate their thorax relative to the pelvis during bipedal walking, which raised questions regarding the origins and development of this characteristic. In this study, we measured the axial rotation of the trunk during bipedal walking in humans and macaques to investigate if intra-trunk axial rotations are observed in non-hominoid primate species. MATERIALS AND METHODS: We collected three-dimensional trunk kinematic data during bipedal walking in six humans and five Japanese macaques. The human subjects walked on a treadmill, and the animal subjects walked on a 5-m runway. During walking, the positions of cluster markers, which defined trunk segments, were recorded by multiple video cameras. Segmental xyz coordinates were digitized, and transverse rotations were calculated using motion analysis software. RESULTS: Although trunk rotations in the global coordinate system were greater in macaques than in humans, the intra-trunk rotation and range of motion showed a similar pattern in the two species. CONCLUSIONS: Thoracic rotation relative to the pelvis during bipedal walking is not unique to the hominid lineage but rather a characteristic generated by the mechanical requirements of bipedal walking. The fact that the range of motion of counter rotation is similar in these species infers that an optimal range of rotation exists for bipedal walking.

[Investigating the relationship between higher life functions, overall mortality, and incidence of care needs in long-term follow-up study of the local population: The Kamogawa Cohort Study].

Objectives　In addition to physical independence such as ADLs, higher-level functional capacity ("instrumental self-maintenance," "intellectual activity," and "social role") are necessary to lead the final stage of life as independently and for as long as possible. Accordingly, in a long-term follow-up study of the local population, we examined the association of health status (total mortality and incidence of care needs) with instrumental independence, intellectual activity, and social role.Methods　We used participant data from the Kamogawa cohort study, which included surveyed use of health service, health status, disease prevalence, and use of long-term care insurance service for Kamogawa citizens in Chiba prefecture from 2003 to 2013. We compared the differences in lifestyle and higher-level functional capacity, by status of death and using the Long-term Care Insurance service. Higher-level functional capacity was assessed with the Tokyo Metropolitan Institute of Gerontology-Index of Competence (TMIG-IC); answer to each question, each domain score, and total score were examined.Results　During the follow-up period to the end of March 2013, 810 deaths and 917 care needs were observed among the 6,503 people who consented to be followed up. The adjusted HR of higher-level functional capacity for all-cause mortality was "instrumental self-maintenance," score 4 or 5 to less than 3: 2.03 (95%CI: 1.59-2.60), "intellectual activity," score 4 to less than 3: 1.39 (95%CI: 1.09-1.77), and "social role," score 4 to less than 3: 1.28 (95%CI: 1.03-1.59). In subgroup analyses by sex, "instrumental self-maintenance" was associated with both men and women, but "intellectual activity" and "social roles" were associated with women only. The adjusted HRs for the incidence of care needs were 1.93 (95%CI: 1.55-2.40) for "instrumental self-maintenance" and 1.30 (95%CI: 1.07-1.58) for "social role." In subgroup analyses by sex, "instrumental self-maintenance" was associated with both genders, but "social role" was observed only for women.Conclusion　Higher-level functional capacity ("instrumental self-maintenance," "intellectual activity," and "social role") was significantly associated with total mortality and incidence of care needs.

Amorphous High-Surface-Area Aluminum Hydroxide-Bicarbonates for Highly Efficient Methyl Orange Removal from Water.

Amorphous high-surface-area aluminum hydroxide-bicarbonates were synthesized starting from AlCl3, base, and bicarbonate in water. Composites with a chemical formulas of [Al13O4(µ-OH)24(H2O)6.5(OH)5.5](HCO3)1.5 (I-NaOH) and [Al13O4(µ-OH)24(H2O)6(OH)6](HCO3) (I-NH3) were obtained by the use of NaOH/NaHCO3 and NH3/NH4HCO3 as base/bicarbonate, respectively. The surface area of the composites was highly dependent on the pH level of the synthetic solution, and composites with high surface areas (ca. 200 m2 g-1) were obtained around pH 7-8. Pore-size distributions determined from the N2 adsorption isotherms showed that I-NH3 and I-NaOH possess mainly large (pore radius rp > 3 nm) and small (rp < 3 nm) pores, respectively, despite similar surface areas. While SEM images showed that both I-NH3 and I-NaOH were aggregates of nanoparticles, the particles were more fused in I-NaOH, which is in line with the existence of small pores and the use of a stronger base (NaOH), which would facilitate the dehydration condensation reaction. The composites were applied as adsorbents to remove methyl orange (MO) from water. The time course of MO adsorption was readily fitted with a pseudo-second-order model, and over 90% MO removal was attained within 10 min with I-NH3, while I-NaOH showed much less MO removal (26%). The MO adsorption isotherm of I-NH3 was reproduced with a Langmuir model with an adsorption capacity of 154 mg g-1. Notably, the aluminum hydroxide-bicarbonates could not absorb methylene blue, which is a cationic dye, while anions (MO and PO43-) were readily absorbed. Solid-state 27Al MAS NMR spectra showed that the concentration of 5-coordinated aluminum species, which may serve as guest binding sites, was higher for I-NH3. These results show that electrostatic interaction between anionic MO and coordinatively unsaturated 5-coordinated cationic aluminum species and the large external surface area of I-NH3 contribute to the highly efficient MO adsorption.

Genetic inhibition of CRMP2 phosphorylation delays Wallerian degeneration after optic nerve injury.

Axonal degeneration occurs in patients with various neurological diseases and traumatic nerve injuries, and Wallerian degeneration is a phenomenon in the prototypical axonal degradation that is observed after injury. Collapsin response mediator protein 2 (CRMP2) is phosphorylated by glycogen synthase kinase 3ß (GSK3ß), and it is involved in Wallerian degeneration after optic nerve injury. We previously developed a CRMP2 knock-in (CRMP2 KI) mouse line, in which CRMP2 phosphorylation by GSK3ß is inhibited; however, Wallerian degeneration in CRMP2 KI mice has not yet been examined. In this study, we examined whether Wallerian degeneration of the optic nerve is suppressed in CRMP2 KI mice. Using one eye removal model, we compared Wallerian degeneration of the optic nerve based on histological and biochemical analyses. Our experimental results indicated that the genetic inhibition of CRMP2 phosphorylation delays Wallerian degeneration after optic nerve injury.

[A Case of Left Vertebral Artery Aneurysm Showing Evoked Potentials on Bilateral Electrode by the Left Vagus Nerve Stimulation to Electromyographic Tracheal Tube].

Previously, we reported a case of brainstem cavernous hemangioma showing false positive responses to electromyographic tracheal tube (EMG tube). We concluded that the cause was spontaneous respiration accompanied by vocal cord movement. We report a case of left vertebral artery aneurysm showing evoked potentials on bilateral electrodes by the left vagus nerve stimulation to EMG tube. An 82-year-old woman underwent clipping of a left unruptured vertebral artery-posterior inferior cerebellar artery aneurysm. General anesthesia was induced with remifentanil, propofol and suxamethonium, and was maintained with oxygen, air, remifentanil and propofol. We monitored somatosensory evoked potentials, motor evoked potentials, and electromyogram of the vocal cord. When the manipulation reached brainstem and the instrument touched the left vagus nerve, evoked potentials appeared on bilateral electrodes. EMG tube is equipped with two electrodes on both sides. We concluded that the left vagus nerve stimulation generated evoked potentials of the left laryngeal muscles, and they were simultaneously detected as potential difference between two electrodes on both sides. EMG tube is used to identify the vagus nerve. However, it is necessary to bear in mind that each vagus nerve stimulation inevitably generates evoked potentials on bilateral electrodes.

[A Case of Brainstem Cavernous Hemangioma Showing False Positive Response to Electromyographic Tracheal Tube].

Brainstem cavernous hemangioma is a complex lesion associated with hemorrhage and neurological deficit. The damage of the vagus nerve is a devastating surgical complication. Therefore, intraoperative anatomical and functional evaluation of this nerve is crucial. We used electromyographic tracheal tube (EMG tube)to monitor electromyogram from the vocal cord. We report a case of brainstem cavernous hemangioma showing false positive response to EMG tube. A 66-year-old woman underwent resection of cavernous hemangioma in the pontine tegmentum. General anesthesia was induced with remifentanl, propofol, and suxamethonium, and was maintained with oxygen, air, remifentanil and propofol. We monitored somatosensory evoked potentials, motor evoked potentials, and electromyogram of the vocal cord, orbicularis oculi, orbicularis oris and lateral rectus. When the manipulation reached brainstem, slight spontaneous respiration (SR) appeared on capnogram. Simultaneously, an alarm rang. Exposed nerves were stimulated electrically. However, there was no electromyographic response on the vocal cord. We concluded that the cause was SR accompanied by vocal cord movement. Remifentanil was increased up to 1 µg x kg(-1) x min(-1). SR did not disappear. Remifentanil was not increased any more without hindering the operation. Her operative course was uneventful. It is necessary to pay attention to false positive response caused by SR with EMG tube.

[Monitoring of Somatosensory Evoked Potentials during Foramen Magnum Decompression of Chiari Malformation Type I Complicated with Syringomyelia: A Report of Two Cases].

Few reports exist on anesthetic management for foramen magnum decompression (FMD) of Chiari malformation type I (CM I) complicated with syringomyelia. In two such cases we monitored somatosensory evoked potentials (SEP). Case 1 : A 40-year-old woman presented with occipital headache and nuchal pain for 2 months; numbness and muscular weakness of bilateral upper limbs for a month. Magnetic resonance imaging (MRI) scan showed CM I complicated with syringomyelia. Case 2 : A 32-year-old man presented with numbness and muscular weakness of bilateral upper limbs for 5 months; numbness and muscular weakness of lower limbs for 2 months. MRI scan showed CM I complicated with syringomyelia. They underwent FMD. In both cases, general anesthesia was induced with remifentanil, propofol and rocuronium, and was maintained with oxygen, air, remifentanil and propofol. Moreover, we monitored SEP. Their operative courses were uneventful. In case 1, SEP latency became shorter after FMD. Her preoperative neurologic symptoms disappeared on first postoperative day. In contrast there was no change of SEP latency after FMD in case 2. His preoperative neurologic symptoms showed no change on fifth postoperative day. SEP monitoring may be a useful index for prediction of early recovery of neurologic symptoms after FMD.

Prey pursuit strategy of Japanese horseshoe bats during an in-flight target-selection task.

The prey pursuit behavior of Japanese horseshoe bats (Rhinolophus ferrumequinum nippon) was investigated by tasking bats during flight with choosing between two tethered fluttering moths. Echolocation pulses were recorded using a telemetry microphone mounted on the bat combined with a 17-channel horizontal microphone array to measure pulse directions. Flight paths of the bat and moths were monitored using two high-speed video cameras. Acoustical measurements of returning echoes from fluttering moths were first collected using an ultrasonic loudspeaker, turning the head direction of the moth relative to the loudspeaker from 0° (front) to 180° (back) in the horizontal plane. The amount of acoustical glints caused by moth fluttering varied with the sound direction, reaching a maximum at 70°-100° in the horizontal plane. In the flight experiment, moths chosen by the bat fluttered within or moved across these angles relative to the bat's pulse direction, which would cause maximum dynamic changes in the frequency and amplitude of acoustical glints during flight. These results suggest that echoes with acoustical glints containing the strongest frequency and amplitude modulations appear to attract bats for prey selection.

[Investigation of the neck swelling caused by accumulation of irrigation fluid during shoulder arthroscopy in the beach-chair position: second report].

BACKGROUND: Previously, we reported that pre- and postoperative measurement of the neck circumference might be an easy and useful measure for prediction of postoperative airway obstruction in shoulder arthroscopy. However, it is suggested that airway pressure to cause a cuff leak around the tracheal tube in a cuff deflated condition (cuff leak pressure) is a predictor of postoperative airway obstruction. We studied a correlation between the neck circumference and the cuff leak pressure. METHODS: Forty patients undergoing shoulder arthroscopy in the beach-chair position were included in this study. There were 30 male and 10 female patients. All patients' neck circumference and cuff leak pressure were compared pre- and postoperatively and with each other. RESULTS: There was a strong correlation between the increase of neck circumference and the increase of cuff leak pressure. CONCLUSIONS: The rate of increase in neck circumference shows the swelling of external tissue of the neck. However, it may not reflect the swelling of the internal tissue containing pharynx, larynx and retrotracheal space. Alternatively, pre- and postoperative measurement of the cuff leak pressure could be a more substantial predictor of postoperative airway obstruction than the rate of increase in neck circumference.

[Seven cases of parathyroidectomy for secondary hyperparathyroidism using methylene blue: suggestion for the method of methylene blue infusion].

BACKGROUND: Intraoperative staining of the parathyroid glands with intravenously administered methylene blue is well described and has been demonstrated as an effective and safe method to facilitate parathyroidectomy. However, there have been several literatures of the development of postoperative neurological toxicity in patients who received methylene blue infusion during parathyroidectomy. We report the method of methylene blue infusion during parathyroidectomy at our institution. METHODS: Seven adult patients who had undergone parathyroidectomy for secondary hyperparathyroidism associated with chronic renal failure were included in this study. Methylene blue was administered at a constant rate of 4 mg x kg(-1) x hr(-1) with a 1% solution just before the start of operation. The infusion was stopped after the first parathyroid gland was identified. RESULTS: The mean dose of methylene blue used was 2.2 +/- 0.8 mg x kg(-1). Consequently, the dose of methylene blue by this method could be decreased to less than half of the previously administered dose (6 mg x kg(-1)) at our institution. CONCLUSIONS: The dose of methylene blue used should be kept to the minimum required to identify the parathyroid glands in each case.

[Investigation of the neck swelling due to accumulation of irrigation fluid during shoulder arthroscopy in the beach-chair position].

BACKGROUND: The primary purpose of this study was to investigate the degree of neck swelling by accumulation of irrigation fluid during shoulder arthroscopy in the beach-chair position. METHODS: Twenty-one patients undergoing shoulder arthroscopy in the beach-chair position were included in this study. There were 16 male and 5 female patients, with a mean age of 58.7 +/- 16.1 years. All patients' weight and neck circumference were compared pre- and postoperatively and correlated to each other. RESULTS: There was a strong correlation between the increase rate of weight and the increase rate of neck circumference (r = 0.69, P < 0.05). CONCLUSIONS: Pre- and postoperative measurement of the neck circumference might be an easy and useful measure for prediction of postoperative airway obstruction.

Variation of thoracolumbar vertebral morphology in anthropoid primates.

OBJECTIVES: Morphological variation among extant primates in the lumbar vertebral column is well studied. However, knowledge concerning the thoracic spine, an important region responsible for supporting and facilitating movement in the upper trunk, remains relatively scarce. Consequently, our comprehension of the functional differentiation exhibited throughout the thoracolumbar vertebral column among various primate species remains constrained. In this study, we examined patterns of morphological variation in the thoracolumbar vertebral column of extant hominoids, cercopithecoids, and Ateles. MATERIALS AND METHODS: We collected external shape data on 606 thoracic and lumbar vertebrae from Homo sapiens, Pan troglodytes, Hylobates lar, Macaca fuscata, Chlorocebus aethiops, Colobus guereza, Ateles geoffroyi, and A. belzebuth. Forty-four landmarks were obtained on the three-dimensional surface. Geometric morphometrics was used to quantify the centroid size and variation of the shapes of thoracic and lumbar vertebrae. RESULTS: Cercopithecoids exhibited greater variation in the size and shape of their thoracic and lumbar vertebrae compared to hominoids and Ateles. Although many vertebral features contributed to the observed variation throughout the thoracolumbar vertebral column within the taxon, the transverse and spinous processes exhibited relatively major contributions. DISCUSSION: Our results suggest that quadrupedal locomotion requires the functional differentiation between thoracic and lumbar vertebrae, and for hominoids, functional adaptation to orthograde posture necessitates a relatively more uniform shape of thoracic and lumbar vertebrae.

Range of rotation of thoracolumbar vertebrae in Japanese macaques.

In humans, the range of thoracic vertebral rotation is known to be greater than that of the lumbar vertebrae due to their zygapophyseal orientation and soft tissue structure. However, little is known regarding vertebral movements in non-human primate species, which are primarily quadrupedal walkers. To understand the evolutionary background of human vertebral movements, this study estimated the range of axial rotation of the thoracolumbar spine in macaque monkeys. First, computed tomography (CT) was performed while passively rotating the trunk of whole-body cadavers of Japanese macaques, after which the motion of each thoracolumbar vertebra was estimated. Second, to evaluate the influence of the shoulder girdle and surrounding soft tissues, specimens with only bones and ligaments were prepared, after which the rotation of each vertebra was estimated using an optical motion tracking system. In both conditions, the three-dimensional coordinates of each vertebra were digitized, and the axial rotational angles between adjacent vertebrae were calculated. In the whole-body condition, the lower thoracic vertebrae had a greater range of rotation than did the other regions, similar to that observed in humans. In addition, absolute values for the range of rotation were similar between humans and macaques. However, in the bone-ligament preparation condition, the upper thoracic vertebrae had a range of rotation similar to that of the lower thoracic vertebrae. Contrary to previous speculations, our results showed that the mechanical restrictions by the ribs were not as significant; rather, the shoulder girdle largely restricted the rotation of the upper thoracic vertebrae, at least, in macaques.