The Effect of Static Stretching Duration on Muscle Blood Volume and Oxygenation.

ABSTRACT: Matsuo, H, Kubota, M, Shimada, S, Kitade, I, Matsumura, M, Nonoyama, T, Koie, Y, Naruse, H, Takahashi, A, Oki, H, Kokubo, Y, and Matsumine, A. The effect of static stretching duration on muscle blood volume and oxygenation. J Strength Cond Res 36(2): 379-385, 2022-Muscle blood volume increases due to stretching; however, the minimum duration of stretching to sustainably increase the muscle blood volume after stretching has not yet been elucidated. This study examined whether the duration of static stretching influenced the muscle blood volume and oxygenation. Ten healthy male subjects participated in this controlled laboratory study. Static stretching of the gastrocnemius muscle was performed for 5 durations (20 seconds, and 1, 2, 5, and 10 minutes). Changes in both the total-Hb (ΔtHb), as an index of blood volume, and tissue oxygenation index (ΔTOI) from baseline were determined using near-infrared spectroscopy. Both the ΔtHb and ΔTOI decreased during stretching and increased after stretching. The minimum value of ΔtHb during stretching did not differ in each of the 5 durations, but minimum ΔTOI progressively decreased with longer durations of stretching. The peak value of ΔtHb after stretching increased with longer durations of stretching. The value of ΔtHb at 5 minutes after the end of stretching increased with more than 2 minutes of stretching compared with 20 seconds of stretching, although the value of ΔtHb did not significantly differ between the 2, 5, and 10 minutes' durations. These findings suggest that a longer duration of stretching elicits a decrease in muscle oxygenation during stretching, and an increase in both the muscle blood volume and oxygenation after stretching. The results indicated that the minimum duration of stretching to sustain an increase in the muscle blood volume after stretching is 2 minutes.

Center of pressure velocities in patients with body lateropulsion: three case report series of Wallenberg's syndrome.

PURPOSE: In patients with Wallenberg's syndrome who present with body lateropulsion (BL), whether the center of pressure (COP) position and velocity characterize postural dysregulation is unknown. We measured time-course changes in COP parameters in three BL patients. METHODS: Three patients with acute Wallenberg's syndrome presented with BL. COP was measured for time-course changes during first standing and every week thereafter. COP positions, which indicate the deviation in the center of gravity, were calculated. COP velocities associated with dynamic movements of the center of gravity were analyzed separately for the BL and non-BL sides. RESULTS: All patients showed that COP position shifted to the BL side in first standing and changed to the center over time. COP velocities to the BL side were fast in first standing. Two of the three patients had significantly faster COP velocities to the BL side than to the non-BL side (p < .05), and one did not. In all three cases, the faster COP velocities to the BL side decreased significantly after 2 weeks compared to the initial standing position (p < .001). The change seemed to be related to the time when independent walking became possible. CONCLUSIONS: Fast COP velocity to the BL side might reflect postural dysregulation in patients with BL. These findings might be useful information for devising effective rehabilitation in patients with BL.

Effects of knee extension exercise starting within 4 h after total knee arthroplasty.

PURPOSE: To determine the beneficial effects of knee extension exercise applied from 4 h after TKA. METHODS: Patients undergoing TKA for osteoarthritis were assigned to early rehabilitation (n = 41) and control rehabilitation (n = 39) groups. Rehabilitation of knee extension exercise was started within 4 h postoperative in the early group and 2 days after surgery in the control group. Joint range of motion and pain were assessed before surgery and at 3 days to 12 months after surgery. Muscle strength and gait parameters were assessed before and 3 weeks after surgery. RESULTS: Extension range of motion was significantly increased in the early group than the control at 3 days, 3 weeks and 6 months after surgery. In gait parameters, peak knee flexion and extension angles during stance phase were significantly improved in the early group than the control group at 3 weeks after surgery. Flexion range of motion was increased in the early group than the control at 12 months after surgery. CONCLUSION: Starting knee extension exercise within 4 h after TKA reduced the early loss of extension range of motion and improved gait pattern and seemed to contribute to be better functional outcome one year after surgery.

Infant with right hemiplegia due to acute encephalopathy with biphasic seizures and late reduced diffusion (AESD): A case report.

RATIONALE: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a condition characterized by biphasic convulsions and disturbance of consciousness. In Japan, the most common pediatric cases of acute encephalopathy are associated with infection. AESD usually occurs in early childhood, with the characteristic magnetic resonance imaging (MRI) appearance called "bright tree appearance." The disease often has neurological sequelae and interferes with the schooling of children and their activities of daily living; however, there are few clinical case reports of hemiplegia caused by AESD. PATIENT CONCERNS: A case with right-sided hemiplegia due to AESD in an 11-month-old girl who was followed up to 30 mo of age. DIAGNOSES: The patient was diagnosed with overlap AESD and hemiconvulsion-hemiplegia-epilepsy syndrome (HHE syndrome), based on the clinical course and imaging findings. DNA tests of her blood and cerebrospinal fluid revealed the presence of human herpesvirus 6. INTERVENTIONS: Pharmacotherapy and rehabilitation therapy. OUTCOME: Gross motor function has recovered considerably, but she had a mild developmental delay at 30 mo old. LESSONS: Hemiplegia due to AESD was extremely rare, and appropriate rehabilitation treatment resulted in recovery of physical function. However, as mild developmental delay was observed, the patient was referred to a specialized facility before entering school.

Functional outcomes after the treatment of hip fracture.

Osteoporotic hip fracture is a major public health issue. Estimation of the outcome and maximization of functional recovery after fracture is very important in the treatment of older patients. The purposes of this study were to clarify the functional outcomes after the treatment of hip fracture and to identify the factors that influence functional recovery. In the present study, 228 patients admitted to an acute-care hospital from January 2016 to June 2018 were evaluated. The patients were categorized into a trochanteric fracture group (n = 128) and a neck fracture group (n = 100). We retrospectively reviewed their ambulation ability 6 months after fracture using the Functional Ambulation Category (FAC) score. The other survey items were the presurgical duration, length of hospital stay, time until beginning to walk using parallel bars, complications affecting treatment, and mortality rate. The 6-month follow-up rate was 54.4% (n = 124). The results showed that the patients with trochanteric fracture were significantly older than those with neck fracture (86 vs. 82 years, respectively; p = 0.03). In total, 85.0% of patients with trochanteric fracture and 92.2% of patients with neck fracture were independent ambulators before injury (FAC score of 4 or 5). The FAC score 6 months after fracture was positively correlated with the FAC score before fracture and at discharge (all p<0.001) and negatively correlated with patient age (p<0.001) and presurgical duration for patients with neck fracture (p = 0.04). There was no statistically significant correlation with the length of hospital stay or the time until beginning to walk using parallel bars. In conclusion, patients with trochanteric fractures were older than those with neck fractures. In both fracture types, walking recovery 6 months after hip fracture was related to the FAC score before injury and at discharge from an acute-care hospital but not to the time until beginning to walk using parallel bars.

Kinematic, kinetic, and musculoskeletal modeling analysis of gait in patients with cervical myelopathy using a severity classification.

BACKGROUND CONTEXT: Although a few reports have shown a change in gait motion in cervical myelopathy (CM) patients using a three-dimensional (3D) gait analysis system, there has been no detailed quantitative investigation of their gait including musculoskeletal modeling parameters. Also, 3D gait analysis using a classification of severity has not been substantiated. PURPOSE: This study aimed to investigate kinematic, kinetic, and musculoskeletal modeling parameters of gait motion in CM patients using a severity classification. STUDY DESIGN: Prospective cohort and cross-sectional study. PATIENT SAMPLE: Forty-two patients with CM and 40 healthy, age-matched volunteers. OUTCOME MEASURES: Lower extremity spatiotemporal, kinematic, kinetic, and musculoskeletal modeling parameters. METHODS: Subjects were classified as to its severity using the Japan Orthopaedic Association score excluding the upper extremity items: group 1 (>10 points); group 2 (7-9 points); and group 3 (<6 points). A 3D motion analysis system and musculoskeletal modeling software were used to obtain the spatiotemporal, kinematic (the lower extremity joints angles in the sagittal plane), kinetic (the lower extremity joints moment and power in the sagittal plane), and musculoskeletal modeling parameters (the muscle-tendon length and velocity). RESULTS: Genu recurvatum, deteriorated lower-extremity joint motion, and muscle-tendon velocity were observed in severe CM patients (group 3). Muscle-tendon velocities of the long head of the biceps femoris in controls and mild CM patients (groups 1 and 2) showed a bimodal waveform in the negative direction during the initial contact and preswing phases, whereas these characteristics were not present in severe CM patients (group 3). CONCLUSIONS: The strategies of the knee joint moment during gait motion in severe CM patients were different from those of the normal gait pattern. The imbalance between agonist and antagonist muscle tissue during gait could be involved in the occurrence of genu recurvatum. It might be important for CM patients to consider improving the contraction or extension velocity of the biceps femoris muscle during each gait phase from the early stages of symptoms.

Relationship between gait parameters and MR imaging in idiopathic normal pressure hydrocephalus patients after shunt surgery.

BACKGROUND: A few previous studies have reported a change in gait motion in idiopathic normal pressure hydrocephalus (iNPH) patients after shunt surgery compared with before shunt surgery; however, there has been no detailed quantitative investigation of gait, including kinetic and kinematic parameters. Furthermore, the relationship between gait parameters and magnetic resonance (MR) imaging has not been confirmed. RESEARCH QUESTION: We investigated the gait motion in patients with iNPH, and evaluated the relationship between kinetic gait parameters and MR imaging before and after shunt surgery. METHODS: The subjects were 12 patients with iNPH who could walk 10 m without aids. A three-dimensional motion analysis system was used to obtain the spatiotemporal, kinetic, and kinematic parameters before and after surgery. Relationships between each gait parameter and MR imaging were assessed. RESULTS: The post-shunt walking speed and step length were increased compared with pre-shunt values. The post-shunt evaluation showed increased range of motion of the hip, knee, and ankle joints in the sagittal plane during the gait cycle. The peak flexion moment of the hip during the stance phase was greater after shunt surgery. The improvement rate of the Evans index was significantly correlated with the improvement rate of walking speed, and the total ranges of motion of the hip and ankle joints in the sagittal plane. SIGNIFICANCE: The propulsive force of the hip and ankle joints was regained after shunt surgery. Normalization of the Evans index could predict improvement in propulsive force after shunt surgery in iNPH.

Increased Anterior Pelvic Angle Characterizes the Gait of Children with Attention Deficit/Hyperactivity Disorder (ADHD).

BACKGROUND: Children with attention deficit/hyperactivity disorder (ADHD) frequently have motor problems. Previous studies have reported that the characteristic gait in children with ADHD is immature and that subjects demonstrate higher levels of variability in gait characteristics for the lower extremities than healthy controls. However, little is known about body movement during gait in children with ADHD. The purpose of this study was to identify the characteristic body movements associated with ADHD symptoms in children with ADHD. METHODS: Using a three-dimensional motion analysis system, we compared gait variables in boys with ADHD (n = 19; mean age, 9.58 years) and boys with typical development (TD) (n = 21; mean age, 10.71 years) to determine the specific gait characteristics related to ADHD symptoms. We assessed spatiotemporal gait variables (i.e. speed, stride length, and cadence), and kinematic gait variables (i.e. angle of pelvis, hip, knee, and ankle) to measure body movement when walking at a self-selected pace. RESULTS: In comparison with the TD group, the ADHD group demonstrated significantly higher values in cadence (t = 3.33, p = 0.002) and anterior pelvic angle (t = 3.08, p = 0.004). In multiple regression analysis, anterior pelvic angle was associated with the ADHD rating scale hyperactive/impulsive scores (ß = 0.62, t = 2.58, p = 0.025), but not other psychiatric symptoms in the ADHD group. CONCLUSIONS: Our results suggest that anterior pelvic angle represents a specific gait variable related to ADHD symptoms. Our kinematic findings could have potential implications for evaluating the body movement in boys with ADHD.

Early transcutaneous electrical nerve stimulation reduces hyperalgesia and decreases activation of spinal glial cells in mice with neuropathic pain.

Although transcutaneous electrical nerve stimulation (TENS) is widely used for the treatment of neuropathic pain, its effectiveness and mechanism of action in reducing neuropathic pain remain uncertain. We investigated the effects of early TENS (starting from the day after surgery) in mice with neuropathic pain, on hyperalgesia, glial cell activation, pain transmission neuron sensitization, expression of proinflammatory cytokines, and opioid receptors in the spinal dorsal horn. Following nerve injury, TENS and behavioral tests were performed every day. Immunohistochemical, immunoblot, and flow cytometric analysis of the lumbar spinal cord were performed after 8 days. Early TENS reduced mechanical and thermal hyperalgesia and decreased the activation of microglia and astrocytes (P<0.05). In contrast, the application of TENS at 1 week (TENS-1w) or 2 weeks (TENS-2w) after injury was ineffective in reducing hyperalgesia (mechanical and thermal) or activation of microglia and astrocytes. Early TENS decreased p-p38 within microglia (P<0.05), the expression levels of protein kinase C (PKC-γ), and phosphorylated anti-phospho-cyclic AMP response element-binding protein (p-CREB) in the superficial spinal dorsal horn neurons (P<0.05), mitogen-activated protein (MAP) kinases, and proinflammatory cytokines, and increased the expression levels of opioid receptors (P<0.05). The results suggested that the application of early TENS relieved hyperalgesia in our mouse model of neuropathic pain by inhibiting glial activation, MAP kinase activation, PKC-γ, and p-CREB expression, and proinflammatory cytokines expression, as well as maintenance of spinal opioid receptors. The findings indicate that TENS treatment is more effective when applied as early after nerve injury as possible.

Postoperative gait analysis and hip muscle strength in patients with pelvic ring fracture.

The aims of present study were (1) to determine changes in kinematic and kinetic variables at 3 and 12 months after open reduction and internal fixation (ORIF) of pelvic ring fracture and (2) to determine the factor(s) associated with gait disorders that correlate with gait parameters measured at 12 months after surgery. Nineteen patients with pelvic ring fractures underwent ORIF and examined at 3 and 12 months postoperatively. The study also included a similar number of age-matched control subjects. Peak hip abduction angle, peak hip extension moment in the stance, peak hip abduction moment, and peak ankle plantarflexion moment at 3 months after ORIF were significantly lower than the respective control values. At 12 months, complete recovery was noted in peak hip abduction moment and peak ankle plantarflexion moment, whereas the recovery in peak hip abduction angle and peak hip extension moment in the stance was partial. The existence of neurological lesions and strength asymmetry of hip abductor and adductor at 3 months post-ORIF correlated with decreased peak hip abduction moment after ORIF. Our results highlighted characteristic gait patterns up to 12 months after ORIF for pelvic fracture, and these patterns correlated with neurological lesion and weakness of hip abductor and adductor muscles.

Changes of blood flow, oxygen tension, action potential and vascular permeability induced by arterial ischemia or venous congestion on the spinal cord in canine model.

It is generally considered that the genesis of myelopathy associated with the degenerative conditions of the spine may result from both mechanical compression and circulatory disturbance. Many references about spinal cord tissue ischemic damage can be found in the literature, but not detailed studies about spinal cord microvasculature damage related to congestion or blood permeability. This study investigates the effect of ischemia and congestion on the spinal cord using an in vivo model. The aorta was clamped as an ischemia model of the spinal cord and the inferior vena cava was clamped as a congestion model at the 6th costal level for 30 min using forceps transpleurally. Measurements of blood flow, partial oxygen pressure, and conduction velocity in the spinal cord were repeated over a period of 1 h after release of clamping. Finally, we examined the status of blood-spinal cord barrier under fluorescence and transmission electron microscope. Immediately after clamping of the inferior vena cava, the central venous pressure increased by about four times. Blood flow, oxygen tension and action potential were more severely affected by the aorta clamping; but this ischemic model did not show any changes of blood permeability in the spinal cord. The intramedullar edema was more easily produced by venous congestion than by arterial ischemia. In conclusions, venous congestion may be a preceding and essential factor of circulatory disturbance in the compressed spinal cord inducing myelopathy.

Knee laxity after staircase exercise predicts radiographic disease progression in medial compartment knee osteoarthritis.

OBJECTIVE: To evaluate whether increased laxity of the knee during daily physical activities such as stair climbing is associated with progression of knee joint osteoarthritis (OA). METHODS: During the years 2001-2003, 136 patients with bilateral primary medial compartment knee joint OA were enrolled in this prospective study. Baseline data collected were body mass index (BMI), muscle power, radiographic joint space width, mechanical axis on standing radiography, and anteroposterior (AP) knee laxity before and after physical exercise. After 8 years of followup, 84 patients were reexamined to assess radiographic changes. Radiographic disease progression was defined as progression of >1 grade on the Kellgren/Lawrence scale. RESULTS: AP knee laxity increased significantly after stair climbing. Patients with OA progression and those without progression did not differ significantly in age, sex, baseline quadriceps muscle strength, mechanical axis, joint space width, and AP knee laxity before exercise. The 2 groups of patients did, however, differ significantly in baseline BMI and change in AP knee laxity due to exercise. The risk of progression of knee OA increased 4.15-fold with each millimeter of increase in the change in AP knee laxity due to exercise and 1.24-fold with each point increase in the BMI. CONCLUSION: Our results indicate that patients with OA progression have significantly greater changes in knee joint laxity during physical activities and a higher BMI than patients without OA progression. These findings suggest that larger changes in knee laxity during repetitive physical activities and a higher BMI play significant roles in the progression of knee OA.

Changes in gait pattern and hip muscle strength after open reduction and internal fixation of acetabular fracture.

OBJECTIVES: To characterize changes in the gait pattern at 3 and 12 months after surgery for acetabular fracture, to assess the relationship between various gait parameters and hip muscle strength, and to determine the factors associated with gait disorders that correlate with gait parameters measured at 12 months after surgery. DESIGN: Prospective cohort study. SETTING: University hospital. PARTICIPANTS: Patients (N=19) with acetabular fractures were treated by open reduction and internal fixation (ORIF) and examined at 3 and 12 months postoperatively. The study also included a similar number of sex- and age-matched control subjects. INTERVENTIONS: Postoperative rehabilitation program. MAIN OUTCOME MEASURES: Spatiotemporal, kinematic, and kinetic variables of gait and strength of hip flexor, adductor, and abductor muscles at 3 and 12 months after ORIF. RESULTS: Walking velocity at 3 months after ORIF was slower in the patients than in the control subjects; however, walking velocity at 12 months was similar in the 2 groups. Although most of the kinematic and kinetic variables showed recovery to control levels at 3 and 12 months after ORIF, recovery was incomplete for pelvic forward tilt and hip abduction moment even at 12 months after ORIF. The greatest loss of muscle strength was noted in the hip abductors, where the average deficit was 35.4% at 3 months and 24.6% at 12 months. There was a significant relationship between hip abductor muscle strength and hip abduction moment at 3 months (R(2)=.63); however, this relationship diminished at 12 months (R(2)=.14). The presence of associated injuries correlated with lack of recovery of the peak hip abduction moment. CONCLUSIONS: Pelvic forward tilt and peak hip abduction moment showed incomplete recovery at 12 months after ORIF with subsequent conventional and home exercise rehabilitation programs. Our results suggest that improvement of hip abductor muscle strength in the early postoperative period could improve the peak hip abduction moment.

Anteroposterior and varus-valgus laxity of the knee increase after stair climbing in patients with mild osteoarthritis.

The aim of this study was to measure exercise-induced changes in knee joint laxity in patients with knee osteoarthritis (OA). The study subjects were 46 female patients with OA and 22 age- and sex-matched normal controls. Radiographs of the knee were taken in all subjects, and the disease severity was graded according to the Kellgren and Lawrence (K-L) grading system. The K-L grade of the control subjects (non-OA group) was 0-1. The OA patients were divided into those with mild OA (K-L grade 2, n = 20) and advanced OA (K-L grade 3-4, n = 26). The subject climbed up and down 8 steps on a staircase apparatus over a period of 10 min. The anteroposterior (A-P) translation was measured with KT2000 arthrometer, and varus-valgus (V-V) rotation was measured on stress radiographs before and after the stair climbing. The Δchange in A-P translation after the exercise was significantly larger in mild OA group than other groups (P < 0.005). The Δchange in V-V rotation after exercise was significantly larger in mild and advanced OA groups than the control (P < 0.003). There were no significant differences in A-P laxity and V-V laxity before exercise among the non-OA, mild OA and advanced OA groups. Exercise resulted in significant changes in A-P knee joint laxity in patients with mild OA relative to the control. The results suggest that daily physical activities (e.g., knee bending or squatting) play a role in the development of knee laxity, particularly in patients with mild OA, and that progression of knee OA seems to correlate with increments of A-P knee joint laxity.

Development of a chronic cervical cord compression model in rat: changes in the neurological behaviors and radiological and pathological findings.

Cervical myelopathy is caused by chronic segmental compression of the spinal cord because of degenerative changes of the spine. However, the exact mechanisms of chronic cervical cord compression are not fully understood. The purpose of this study was to validate a new animal model of chronic cervical cord compression capable of reproducing the clinical course without laminectomy in rats. A polyethylene line attached to a plastic plate was fastened with three turns around the vertebral body of C4 in 1-month-old rats. After surgery, the polyethylene line grows deeper into the dorsal wall of the spinal canal along with the growth of the spinal canal and vertebral body, producing a gradual compression of the spinal cord. The results show that this cervical canal stenosis (CCS) model in rats caused motor deficits and sensory disturbances 9 months after initiating CCS; however, no clinical manifestations took place until 6 months. The intramedullary high-intensity area on T2-weighted images was observed in 70% of the CCS model rats at 12 months after initiating CCS. In histological sections, the spinal cord was compressed along the entire circumference at 12 months after initiating CCS. The number of ventral neurons was decreased, and the white matter showed wallerian degeneration. This model might reproduce characteristic features of clinical chronic cervical cord compression, including progressive motor and sensory disturbances after a latency period and insidious neuronal loss, and represents chronic compression of the cervical spinal cord in humans.

Lidocaine cytotoxicity to the zygapophysial joints in rabbits: changes in cell viability and proteoglycan metabolism in vitro.

STUDY DESIGN.: To examine whether lidocaine cytotoxicity to chondrocytes has been implicated in the development of osteoarthritis of the zygapophysial joints. OBJECTIVE.: This study was performed to determine the effects of varying concentrations and exposure times of lidocaine on the viability and proteoglycan metabolism of rabbit zygapophysial chondrocytes in vitro. SUMMARY OF BACKGROUND DATA.: Zygapophysial joint injections are commonly administered with lidocaine for chronic spinal pain in orthopedic treatment. A lot of studies on the effect of zygapophysial joint injections are clinical, but many questions on the effect of lidocaine to zygapophysial chondrocytes remain unanswered. METHODS.: Cartilage was obtained from zygapophysial joints of adult rabbits. Chondrocytes in alginate beads were cultured in medium containing 6% fetal calf serum at 370 mOsmol at cell densities of 4 million cells/mL. They were then cultured for 24 hours under 21% oxygen with 0.125%, 0.25%, 0.5%, and 1% lidocaine, and without lidocaine as control. The cell viability profile across intact beads was determined by manual counting using fluorescent probes (LIVE/DEAD assay) and transmission electron microscopy. Lactate production was measured enzymatically as a marker of energy metabolism. Glycosaminoglycan (GAG) accumulation was measured using a modified dimethylmethylene blue assay. RESULTS.: Cell viability decreased in a time- and dose-dependent manner in the concentration range of 0.125% to 1.0% lidocaine under the confocal microscope. Under the electron microscope, apoptosis increased as the concentration of lidocaine increased. GAG accumulation/tissue volume decreases as the concentration of lidocaine increased. However, GAG produced per million cells and the rate of lactate production per live cell was significantly higher for cells cultured at 0.5% and 1% lidocaine than the control group. CONCLUSION.: While these in vitro results cannot be directly extrapolated to the clinical setting, this data suggestcaution in prolonged exposure of zygapophysial cartilage to high concentration lidocaine.

High-resolution magnetic resonance imaging and 18FDG-PET findings of the cervical spinal cord before and after decompressive surgery in patients with compressive myelopathy.

STUDY DESIGN: Evaluation of cervical spinal cord (CSC) of patients with compressive myelopathy by magnetic resonance imaging (MRI) and high-resolution (18F)fluoro-deoxyglucose (18FDG) positron emission tomography (PET). OBJECTIVE: To determine changes in morphology, intramedullary signal intensity, and glucose metabolic rate in CSC after decompression, and to assess the utility of 18FDG-PET in evaluation of patients with cervical myelopathy. SUMMARY OF BACKGROUND DATA: The significance of CSC enlargement after decompression and signal intensity changes within the cord remain elusive. No data are available on metabolic activity of the compressed CSC. Only a few studies have examined correlation between high-resolution MRI and 18FDG-PET neuroimaging in cervical myelopathy. METHODS: We studied 24 patients who underwent cervical decompressive surgery in terms of postoperative neurologic improvement and changes in MRI and 18FDG-PET. Neurologic status was assessed by the Japanese Orthopedic Association scoring system (17-point scale). Signal intensity change in the cord was qualitatively assessed on both T1- and T2-weighted images. The transverse area of the CSC on MRIs and glucose metabolic rate (standardized uptake value [SUV]) from 18FDG-PET were measured digitally. RESULTS: Neurologic improvement correlated with preoperative CSC transverse area at maximal compression (P < 0.01) and at follow-up (P < 0.001) and with mean SUV before surgery (P < 0.01) and at follow-up (P < 0.05). Preoperative signal intensity change on MRIs (low intramedullary signal intensity abnormality on T1-weighted image and high intramedullary on T2-weighted image) correlated negatively with neurologic improvement rate (P < 0.05). The transverse area of the CSC was significantly smaller after surgery in patients with preoperative MRI signal intensity changes (P < 0.05). The SUV at follow-up tended to normalize in association with neurologic improvement. CONCLUSION: Our results showed that postoperative neurologic improvement in patients with cervical compressive myelopathy correlated with increased transverse area of the spinal cord, signal intensity change on both T1- and T2-weighted image, and the mean SUV.

Changes in blood flow, oxygen tension, action potentials, and vascular permeability induced by arterial ischemia or venous congestion on the lumbar dorsal root ganglia in dogs.

It is generally believed that radiculopathy associated with the degenerative conditions of the spine may result from both mechanical compression and circulatory disturbance. However, the basic pathophysiology of circulatory disturbance induced by ischemia and congestion is not fully understood. This study investigated the effect of ischemia and congestion on the dorsal root ganglion (DRG) using an in vivo model. The sixth and seventh lumbar laminae were removed and the seventh lumbar DRG was exposed using adult dogs. The aorta was clamped as an ischemic model in the DRG, and the inferior vena cava was clamped as a congestion model at the sixth costal level for 30 min using forceps transpleurally. Measurements of blood flow, partial oxygen pressure, and action potentials in the DRG were recorded over a period of 1 h after clamp release. Finally, we examined the status of intraganglionic blood permeability under a fluorescence microscope following injection of Evans blue albumin into the cephalic vein to determine the type of circulatory disturbance occurring in the DRG. Immediately after inferior vena cava clamping, the central venous pressure increased approximately four times and marked extravasation of protein tracers was induced in the lumbar DRG. Blood flow, partial oxygen pressures, and action potentials within the DRG were more severely affected by the aorta clamping; however, this ischemic model did not reveal any permeability changes in the DRG. The permeability change in the DRG was more easily increased via venous congestion than by arterial ischemia. The intraganglionic venous flow was stopped with compression at much lower pressures than that needed to impact arterial flow. From a clinical perspective, intraganglionic edema formation, rather than arterial ischemia, may be an earlier phenomenon inducing DRG dysfunction.

Visualization of intraneural edema using gadolinium-enhanced magnetic resonance imaging of carpal tunnel syndrome.

BACKGROUND: In general, carpal tunnel syndrome (CTS) is diagnosed based mainly on clinical findings and electrophysiology. However, the pathological state of the compressed median nerve could not be shown on imaging. Gadolinium-enhanced magnetic resonance (MR) imaging may give us an idea about the status of the blood-nerve barrier of peripheral nerves. Therefore, detecting intraneural edema may be a way of diagnosing entrapment neuropathy. The present study investigated the diagnostic role of gadolinium-enhanced MR imaging of CTS. METHODS: The subjects were 23 patients (34 hands) with idiopathic CTS. To serve as control subjects, 12 wrists of asymptomatic volunteers were studied. Using the spin-echo method, T1- and T2-weighted axial MR images were obtained. Intravenously injected gadolinium was used to obtain enhanced images. We studied the relation between nerve enhancement and the symptomatology. RESULTS: After intravenous injection of gadolinium, there was no enhancement of the unaffected nerves in the carpal tunnels of the control group. Gadolinium enhancement was found in only 87% of patients with CTS who visited the hospital at an early stage and therefore had no nerve deficiency on electrophysiological studies (39%). Based on this finding, during the early stages when the nerve is in a state of neuropraxia, gadolinium-enhanced MR imaging of the median nerve might prove to be the most sensitive modality for detecting early nerve dysfunction. MR imaging also revealed a higher frequency of enhancement in the advanced stage of CTS with muscle atrophy. CONCLUSIONS: We conclude that gadolinium-enhanced MR imaging can detect not only morphological changes but also pathological changes of the median nerve in patients with CTS. Currently, gadolinium-enhanced-MR imaging is probably most commonly used to image patients who have ambiguous electrodiagnostic studies and clinical examination in an early stage of CTS.

Physical limitations to tissue engineering of intervertebral disc cells: effect of extracellular osmotic change on glycosaminoglycan production and cell metabolism. Laboratory investigation.

OBJECT: In this study, the authors examined how physiological levels of extracellular osmolality influence proteoglycan accumulation in nucleus pulposus cells in a 3D culture system. METHODS: Cells were isolated from the nucleus pulposus of caudal discs obtained from 18- to 24-month-old bovines. They were cultured for 6 days in alginate beads at 4 million cells/ml in Dulbecco modified Eagle medium containing 6% fetal bovine serum under 21% O2. Medium osmolality was altered by NaCl addition between 270 and 570 mOsm and monitored using a freezing point osmometer. The cell viability profile was determined by manual counting after trypan blue staining. Profiles across intact beads were determined by manual counting by using fluorescent probes and a transmission electron microscope. Lactate production was measured enzymatically, and glycosaminoglycan (GAG) accumulation was measured using a dimethylmethylene blue assay. Rate of sulfate GAG synthesis was measured using a standard [35S]sulfate radioactive method. RESULTS: The cell viability was similar for the high- and low-osmolality cultures. However, confocal microscopy showed that the cells were the largest at 270 mOsm and became smaller with increasing osmotic pressure. The GAG production was largest at 370 mOsm, the capacity for GAG production and cell metabolism (lactate production) was low under hypoosmolality and hyperosmolality, and cell death was observed on electron microscopy. CONCLUSIONS: In the authors' model, the prevailing osmolality was a powerful regulator of GAG accumulation by cultured nucleus cells. Thus, these results indicate that GAG synthesis rates are regulated by GAG concentration, with implications both for the cause of degeneration and for tissue engineering.