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Compression with or without early ambulation in the prevention of post-thrombotic syndrome: a systematic review.

INTRODUCTION: The aim of this study was to assess whether there is enough evidence to suggest that compression with or without early ambulation after proximal DVT reduces the risk of post-thrombotic syndrome (PTS). METHODS: Systematic review based on electronic and hand searching of the relevant literature. RESULTS: Four randomized studies were identified and despite the fact that there was lack of uniformity in reporting standards all but one showed significant risk reduction of PTS using compression. No difference in recurrent thromboembolic events (DVT or pulmonary embolism) was observed between the compression and control group. In one study the early outcome from the combination of early ambulation with compression was faster reduction of swelling with better well-being without increased risk of PE compared to the control group. Pooled analysis of all studies showed that PTS developed in 24% (61/254) in the compression group and in 46% (110/239) in the control group (chi2=25.36, p=0.0001; OR: 0.37, 95%CI: 0.25, 0.54; RR: 0.52, 95%CI: 0.40, 0.67; and RRR: 0.48, 95%CI: 0.33, 0.60) with a 48% risk reduction from the use of compression. CONCLUSION: Despite the fact that compression with or without early ambulation appears to be safe and it is more often associated with a decreased rate of PTS, the four existing studies do not permit meaningful data comparison due to lack of uniformity in reporting standards.

Bandages↗

Novel model to analyze the effect of a large compressive follower pre-load on range of motions in a lumbar spine.

A 3-D finite element model (FEM) of the lumbar spine (L1-S1) was used to determine the effect of a large compressive follower pre-load on range of motions (ROM) in all three planes. The follower load modeled in the FEM produced minimal vertebral rotations in all the three planes. The model was validated by comparing the disc compression at all levels in the lumbar spine with the corresponding results obtained by compressing 10 cadevaric lumbar spines (L1-S1) using the follower load technique described by Patwardhan et al. [1999. A follower load increases the load-carrying capacity of the lumbar spine in compression. Spine 24(10), 1003-1009]. Further validation of the model was performed by comparing the lateral bending and torsion response without pre-load and the flexion-extension response without pre-load and with an 800 N follower pre-load with those obtained using cadaver lumbar spines. Following validation, the FEM was subjected to bending moments in all three planes with and without compressive follower pre-loads of up to 1200 N. Disc compression values and the flexion-extension range of motion under 800 N follower pre-load predicted by the FEM compared well with in vitro results. The current model showed that compressive follower pre-load decreased total as well as segmental ROM in flexion-extension by up to 18%, lateral bending by up to 42%, and torsion by up to 26%.

Adaptation, Physiological↗

The efficacy of a new portable sequential compression device (SCD Express) in preventing venous stasis.

OBJECTIVE: It has been previously shown that the SCD Response Compression System, by sensing the postcompression refill time of the lower limbs, delivers more compression cycles over time, resulting in as much as a 76% increase in the total volume of blood expelled per hour. Extended indications for pneumatic compression have necessitated the introduction of portable devices. The aim of our study was to test the hemodynamic effectiveness of a new portable sequential compression system (the SCD Express), which has the ability to detect the individual refill time of the two lower limbs separately. METHODS: This was an open, controlled trial with 30 normal volunteers. The new SCD Express was compared with the SCD Response Compression System in the supine and semirecumbent positions. The refilling time sensed by the device was compared with that determined from velocity recordings of the superficial femoral vein using duplex ultrasonography. Baseline and augmented flow velocity and volume flow, including the total volume of blood expelled per hour during compression with the SCD Express, were compared with those produced by the SCD Response compression system in the same volunteers and positions. RESULTS: Both devices significantly increased venous flow velocity as much as 2.26 times baseline in supine position and 2.67 times baseline in semirecumbent position (all P < .001). There was a linear relationship between duplex ultrasonography-derived refill time and the SCD Express-derived refill time in both the supine (r = 0.39, P = .03) and semirecumbent (r = 0.71, P < .001) positions but not with the SCD Response. Refill time measured by the SCD Express device was significantly shorter and the cycle rate higher in comparison with the SCD Response in both positions. The single-cycle flow velocity and volume flow parameters generated by the two devices were similar in both positions. However, median (interquartile range) total volume of blood expelled per hour was slightly higher with the SCD Express device in the supine position (7206 mL/h [range, 5042-8437] vs 6712 mL/h [4941-10,676]; P = .85) and semirecumbent position (4588 mL/h [range, 3721-6252] vs 4262 mL/h [3520-5831]; P = .22). Peak volume of blood expelled per hour by the SCD Express device in the semirecumbent position was significantly increased by 10% in comparison with the SCD Response (P = .03). CONCLUSIONS: Flow velocity and volume flow enhancement by the SCD Response and SCD Express were essentially similar. The latter, a portable device with optional battery power that detects the individual refill time of the lower limbs separately, is anticipated to be associated with improved overall compliance and therefore optimized thromboprophylaxis. Studies testing its potential for improved efficacy in preventing deep vein thrombosis are justified.

Adolescent↗

Interface pressure and stiffness of ready made compression stockings: comparison of in vivo and in vitro measurements.

OBJECTIVE: It is unknown if the pressure values of compression stockings indicated by the producers correspond to the actual compression pressure exerted in vivo. This study compared pressure and stiffness of ready-made compression stockings (Venosan) of different classes, measured on the leg and by laboratory testing. METHODS: This was an experimental study conducted in a textile laboratory of a company that manufactures compression stockings. Twelve legs from healthy volunteers were fitted with ready-made calf-length compression stockings of the European classes I, II and III. In addition, two class I stockings were applied over each other. The in vivo interface pressure was measured using the medical stocking tester (MST) in position B1, eight cm proximal to the inner ankle. Stiffness was defined by an increase of pressure due to an increase of stretch that reflects the elastic property of the textile and was assessed by measuring the difference of interface pressure between standing and supine position at B1. In the laboratory, the MST was used to check the pressure of these stockings on wooden leg models. Then circular slices were cut out from the stockings at the B1 level and stretched by a Zwick dynamometer in the transverse direction. Force/extension-curves were plotted, from which the pressure and stiffness of each individual stocking was calculated. RESULTS: The pressure profile measured on four positions along the leg by MST showed a degressive gradient on the wooden model but not on the human leg due to the measuring geometry in the ankle region. Pressure values on the leg correspond to the in vitro measurements calculated from the force/extension-curve with a bias (difference of the means) of -2.1 and 4.1 mm Hg. In 95% of the subjects, the difference was between -10.1 and 5.8 mm Hg (Bland Altman plot). The correlation between in vivo and in vitro measurement was highly significant (P < .0001, Spearman correlation coefficient; r = .8161). In vivo and in vitro measurement shows an increase of stiffness with increasing compression classes. The highest values are found for two class I stockings applied over each other. CONCLUSION: Pressure and stiffness can be measured in vivo, correlate well with laboratory findings, and should be used in future studies, especially when different compression devices are to be compared.

Adult↗

Effect of acute nerve root compression on endoneurial fluid pressure and blood flow in rat dorsal root ganglia.

The objective of the current study was to test the hypothesis that crush injury to nerve root increases endoneurial fluid pressure (EFP) and decreases blood flow in the associated dorsal root ganglion (DRG). A total of 21 adult, female Sprague-Dawley rats had their left L5 nerve root and DRG exposed. The L5 nerve root was clamped for 2 s with a vascular suture clip just proximal to the DRG (compression group). Sham-operated animals without compression were used for control (control group). EFP was recorded with a servo-null micropipette system using a glass micropipette with tip diameter of 4 mum before and after 3 h of treatment. After the final measurement of EFP, DRG was excised and processed for histology. Blood flow in the DRG was continuously monitored by laser Doppler flow meter for 3 h. Three hours after treatment, EFP was 4.7+/-2.7 cm H(2)O in the compression group and 2.2+/-1.2 cm H(2)O in the control group (P<0.05). Edema was the principal pathologic findings seen consistently in the DRG from animals in the compression group. Blood flow in the compression group was reduced 10 min after compression. This reduction was statistically significant compared with that of the control (P<0.01). An acute compression to the nerve root increased endoneurial edema, increased EFP in the associated DRG, and reduced DRG blood flow. This combination of increased EFP and decreased blood flow in the DRG may result in neuronal ischemia and sensory dysfunction. These acute pathophysiologic changes may thus have a role in the pathogenesis of low back pain and sciatica due to disc herniation and spinal canal stenosis.

Acute Disease↗

Preservation and analysis of nonequilibrium solute concentration distributions within mechanically compressed cartilage explants.

Solute transport within articular cartilage is of central importance to tissue physiology, and may mediate effects of mechanical compression on cell metabolism. We therefore developed and applied a freeze-substitution method for fixation of cartilage explant disks which had been compressed axially during radial solute desorption. Dextrans were used as model solutes. Explant morphology was well preserved and nonequilibrium solute concentration distributions were stable for several hours at room temperature. For desorption from explants compressed statically to 0-46% strain, analysis of laser confocal images and comparison to a theoretical model permitted measurement of effective diffusivities. Results were consistent with previous studies suggesting a role for transport limitations in mediating the decreases of chondrocyte metabolic rates associated with static compression. In explants compressed dynamically (23+/-5% strain at 0.001 Hz), evidence was obtained for the augmentation of effective transport rate of 3 kDa dextrans by oscillatory interstitial fluid flows. This suggests that augmented solute transport may play a role in mediating the increases of chondrocyte metabolic rates associated with dynamic compression. Methods appear suitable for quantitative studies of transport within mechanically compressed cartilage-like tissues, and may be valuable for identification of loading environments which optimize solute transport in tissue engineering applications.

Animals↗

Cell and nucleus deformation in compressed chondrocyte-alginate constructs: temporal changes and calculation of cell modulus.

Mechanical loading is essential for the homeostasis of articular cartilage and may be necessary for achieving functional tissue engineered cartilage repair using isolated cells seeded in scaffolds such as alginate. Chondrocyte mechanotransduction is poorly understood, but may involve cell deformation and associated distortion of intracellular organelles. The present study used confocal microscopy to examine cell and nucleus morphology in isolated chondrocytes compressed in alginate constructs. Compression of 2% alginate resulted in cell deformation from a spherical to an oblate ellipsoid morphology with conservation of cell volume. Cell deformation was associated with deformation, to a lesser degree, of the nucleus. Despite constant cell deformation over a 25 min period of static compression, the nucleus deformation reduced significantly, particularly in the axis perpendicular to the applied compression. Constructs made of a lower alginate concentration exhibited a reduced compressive modulus with an altered cellular response to compression. In 1.2% alginate, compression resulted in cell deformation which was initially of a similar magnitude to that in 2% alginate but subsequently reduced over a 60 min period reflecting the viscoelastic behaviour of the gel. This phenomenon enabled the calculation of a stress-strain relationship for the cell with an estimated Young's modulus value of approx. 3 kPa.

Alginates↗

Joint compression alters the kinematics and loading patterns of the intact and capsule-transected AC joint.

High compressive loads are transmitted through the shoulder across the acromioclavicular (AC) joint to the axial skeleton during activities of daily living and can lead to early joint degeneration or instability. The objective of this study was to quantify the effect of joint compression on the biomechanics of the intact and capsule-transected AC joint during application of three loading conditions. A robotic/universal force-moment sensor testing system was utilized to apply an anterior, posterior or superior load of 70 N in combination with 10 or 70 N of joint compression to fresh-frozen cadaveric shoulders (n=12). The application of joint compression to the intact AC joint decreased the posterior translation in response to a posterior load (-6.6+/-2.5 vs -3.7+/-1.0 mm, p<0.05). Joint compression also decreased the in situ force in the superior AC capsule by 10 N while increasing the joint contact force by 20 N for all loading conditions (p<0.05). The application of joint compression to the capsule-transected AC joint significantly decreased the amount of posterior and superior translation during posterior (-12.7+/-6.1 vs -5.5+/-3.2 mm, p<0.05) and superior (5.3+/-2.9 vs 4.2+/-2.3 mm, p<0.05) loading, respectively, while significantly increasing the coupled translations (anterior-posterior, superior-inferior or proximal-distal) in all loading conditions (p<0.05). The joint contact force also significantly increased by 20 N for all loading conditions (p<0.05). This quantitative data suggests: (1) common surgical techniques such as distal clavicle resection, which initially reduce painful joint contact, may cause unusually high loads to be supported by the soft tissue structures at the AC joint; and (2) compressive loads transmitted across a capsule-transected AC joint could be concentrated over a smaller area due to the increased coupled motion and joint contact force.

Acromioclavicular Joint↗

Lumbar vertebral body compressive strength evaluated by dual-energy X-ray absorptiometry, quantitative computed tomography, and ashing.

Bone densitometry with DXA (dual energy X-ray absorptiometry) and QCT (quantitative computed tomography) techniques are used for in vivo assessment of bone strength and thereby prediction of fracture risk. However, only few in vitro studies have investigated and compared these techniques' ability to determine vertebral compressive strength. The aim of the present study was to (1) assess the predictive value of DXA, QCT, and pQCT (peripheral QCT) for vertebral bone compressive strength assessed by mechanical testing; (2) describe both linear and power relationship between density and strength; and (3) evaluate whether gender-related differences in the above relations were present. The material comprised human lumbar vertebrae L3 from 51 women and 50 men (age range: 18 to 96 years). The study showed that both DXA and CT techniques (QCT and pQCT) have a high predictive value for vertebral strength. The DXA BMD had a high correlation with maximum compressive load (r2 = 0.86). The QCT and pQCT had high correlations with maximum compressive stress (r2 = 0.75 and r2 = 0.86, respectively). The correlation between ash density of the biomechanically tested specimen and maximum compressive stress was r2 = 0.88. There were no differences between linear and power fit in the degree of determination between density and strength. There was no gender-related difference in the relationship between volumetric density and maximum compressive stress. In conclusion, it was demonstrated that DXA, QCT, and pQCT are ex situ equally capable of predicting vertebral compressive strength with a degree of determination (r2) between 75% and 86%. No differences were found between linear and power analysis of the relationship between density and strength, and no difference was found in the density strength relationship between women and men.

Absorptiometry, Photon↗

Compression behavior of orthorhombic paracetamol.

PURPOSE: Orthorhombic crystals of paracetamol exhibit good technological properties during compression. The purpose of this study was to investigate the compression behavior of this substance and to compare it to that of monoclinic paracetamol. From the crystal structure, it could be hypothesized that sliding planes are present in the orthorhombic form, and could be responsible for an increase in crystal plasticity. METHODS: Compression of pure orthorhombic or monoclinic paracetamol tablets was carried out on a fully instrumented single punch machine. Data was used to establish Heckel's profiles. Images of compressed crystals were obtained by scanning electron microscopy. RESULTS: Tabletability of the orthorhombic crystals was far better than that of the monoclinic ones, and capping was not observed even at high compression pressure. Compared to the monoclinic form, orthorhombic paracetamol exhibited greater fragmentation at low pressure, increased plastic deformation at higher pressure, and lower elastic recovery during decompression. Plastic behavior was confirmed by SEM - micrographs showing that crystals folded under pressure. A compactibility study showed that the nature of interparticle bonds was similar for both polymorphs, the number of bonds being greater for orthorhombic paracetamol. CONCLUSIONS: Unlike the monoclinic form, orthorhombic paracetamol is suitable for the direct compression process. The crystalline structure accounts for its better compression behavior, because of the presence of sliding planes.

Acetaminophen↗

Assessment of optic nerve compression in Graves' ophthalmopathy. The usefulness of a quick T1-weighted sequence.

PURPOSE: Diagnosis of optic nerve compression can be difficult in patients with equivocal clinical signs. We examined the usefulness of a quick coronal MR sequence performed at a predetermined plane as a screening tool for selecting patients at high risk of optic nerve compression. MATERIAL AND METHODS: Direct coronal images of the orbit were obtained in 37 patients with Graves' disease in a predetermined plane. The muscular indices (MI) of each orbit were calculated. Mann-Whitney U-Wilcoxon rank sum test was used to assess if there was any statistically significant difference between patients with and without signs of optic nerve compression. The ROC curve was used to identify a value useful for discriminating patients with a higher risk of developing optic nerve compression. RESULTS: There was a statistically significant difference (p<0.05) in the MI between patients with and without optic nerve compression. An MI of -0.48 had 100% sensitivity, 89% specificity and 91% accuracy in identifying patients with optic nerve compression. CONCLUSION. A quick coronal MR image obtained at the mid-orbital plane is useful in screening patients with Graves' disease for optic nerve compression.

Female↗

Compression of EMG signals with wavelet transform and artificial neural networks.

This paper presents a hybrid adaptive algorithm for the compression of surface electromyographic (S-EMG) signals recorded during isometric and/or isotonic contractions. This technique is useful for minimizing data storage and transmission requirements for applications where multiple channels with high bandwidth data are digitized, such as telemedicine applications. The compression algorithm proposed in this work uses a discrete wavelet transform for spectral decomposition and an intelligent dynamic bit allocation scheme implemented by an approach using the Kohonen layer, which improves the bit allocation for sections of the S-EMG with different characteristics. Finally, data and overhead information are packed by entropy coding. The results for the compression of isometric EMG signals showed that this algorithm has a better performance than standard wavelet compression algorithms presented in the literature (presenting a decrease of at least 5% in per cent residual difference (PRD) for the same compression ratio), and a performance that is comparable with the performance of algorithms based on an embedded zero-tree wavelet. For isotonic EMG signals, its performance is better than the performance of the algorithms based on embedded zero-tree wavelets (presenting a decrease in PRD of about 3.6% for the same compression ratios, in the useful compression range).

Algorithms↗

The 'instantaneous' compressive modulus of human articular cartilage in joints of the lower limb.

METHODS: The instantaneous compressive modulus of articular cartilage was surveyed in 11 sets of human lower limb joints obtained from the ipsilateral side. The average modulus for the entire joint surface of each joint and the topographical variations in the modulus within each joint were examined for all 11 sets, and subjected to statistical analysis. RESULTS: Within each set of joints (hip, knee and ankle), the ankle always had a significantly greater mean compressive modulus than the hip and knee (P < 0.001-P < 0.05). In seven sets of joints, there was no significant difference between the mean compressive moduli of the knee and hip joints. In three sets of joints, the compressive modulus of the knee was significantly greater than that of the hip (P < 0.001-P < 0.01), while in only one set of joints was the compressive modulus of the hip significantly greater than that of the knee (P < 0.01). CONCLUSION: The topographical variations in the cartilage instantaneous compressive modulus over the surfaces of the lower limb joints were matched by differences in the stresses occurring in different areas of each joint. The results of the present study corroborate previous findings and show that the site-specific stresses and corresponding values of the instantaneous cartilage compressive modulus over the surfaces of lower limb joints were correlated (r = 0.82 at P < 0.01), thus adding credence to the conditioning hypothesis of cartilage by prevalent stress.

Adult↗

Mucopolysaccharidoses and spinal cord compression: case report and review of the literature with implications of bone marrow transplantation.

OBJECTIVE AND IMPORTANCE: We present a patient with mucopolysaccharidosis with spinal cord compression, and we review previously published cases. This is the first published case of a patient with mucopolysaccharidosis with spinal cord compression who has undergone bone marrow transplantation. CLINICAL PRESENTATION: A 2-year-old patient with Hurler syndrome underwent bone marrow transplantation. Although the bone marrow transplantation improved many of the systemic effects of Hurler syndrome, the patient presented at 8 years of age with a cervical myelopathy. Magnetic resonance imaging revealed soft tissue compression of the upper cervical cord. The literature review demonstrates that spastic tetraparesis, secondary to cervical cord compression, is the most common presentation of this subgroup of patients. INTERVENTION: A suboccipital craniectomy and C1-C5 laminectomy and decompression with duraplasty were performed. Pathological examination of compressive soft tissue and lamina was consistent with mucopolysaccharidosis. Postoperatively, the patient showed substantial improvement in neurological function. CONCLUSION: Mucopolysaccharidoses can induce a compressive "metabolic myelopathy." Decompressive procedures have shown significant improvement in neurological function in the majority of patients without spinal instability. Bone marrow transplantation may allow more patients with mucopolysaccharidoses to survive long enough to require neurosurgical treatment in the future. The effect of bone marrow transplantation on the prevention of spinal cord compression is unclear.

Bone Marrow Transplantation↗

The role of spinal flexion and extension in changing nerve root compression in disc herniations.

Changes in nerve root compression forces with spinal motion were measured on six freshly frozen adult cadaver spine specimens. A model was devised to represent a herniated disc at the L4-5 level. This was done using an anterior approach placing a compression-measuring device through the disc at the L4-5 level and against the L5 root. An accelerometer was used to monitor the range of motion of the spine. Because the compression device was held in a static position, the only variable was the tautness of the nerve root across the tip of the device. By simultaneously monitoring motion and force delivered at the tip of the compression meter placed at the nerve root, we were able to quantitate nerve root tension forces across the tip of the measuring device in relation to spinal motion. The force was measured with controls as well as in flexion and extension. In addition, the force was measured as traction was applied to the L5 root. The amount of compressive force and tension in the nerve root increased with flexion of the spine and decreased with extension of the spine. In conclusion, flexion of the lumbar spine increased the compressive force on the L5 root and extension decreased the compressive force on the L5 root.

Cadaver↗

Experimental acute dorsal compression of cat spinal cord: correlation of magnetic resonance signal intensity with spinal cord evoked potentials and morphology.

STUDY DESIGN: Acute dorsal compression of the spinal cord was applied to adult cats, and magnetic resonance signal intensity, spinal cord evoked potentials, and morphologic changes of the spinal cord were examined after 5 hours. OBJECTIVES: The present study investigated the correlation of magnetic resonance signal intensity with spinal cord evoked potentials and spinal cord morphology after 5 hours of spinal cord compression in cats. SUMMARY OF BACKGROUND DATA: Neurologic prognosis of the injury might be predicted by an analysis of magnetic resonance signal intensity pattern. Little information is available on relationships between magnetic resonance images and functional or morphologic damage of spinal cord in acute animal experiments. METHODS: Acute dorsal compression of the spinal cord was performed in 24 anesthetized cats. After laminectomy, the L2 segment was compressed for 5 hours. Spinal cord evoked potentials were recorded by electrodes placed in the epidural space at L4, and the spinal cord was stimulated at T12. The animals were divided into four groups based on changes in the amplitude of spinal cord evoked potentials. Immediately after compression for 5 hours, magnetic resonance images were obtained. Signal intensity of the spinal cord was measured on sagittal midline images. Morphologic changes were assessed. RESULTS: Spinal compression significantly increased the signal intensity of the L1, L2, and L3 segments on T2-weighted and proton density-weighted images. The increase in signal intensity was remarkable in the animals whose spinal cord evoked potentials were reduced greatly (< 40% of the control group). Histologically, edema was present in the high intensity area on T2-weighted and proton density-weighted images. CONCLUSIONS: In summary, the present study documents that spinal compression causes tissue edema, which produces high signal intensity on magnetic resonance imaging. The magnetic resonance signal intensity is correlated closely with decreased amplitude of spinal cord evoked potentials.

Acute Disease↗

Pain drawings in the assessment of nerve root compression: a comparative study with lumbar spine magnetic resonance imaging.

STUDY DESIGN: Prospective comparative study of pain drawings with findings on lumbar spine magnetic resonance imaging. OBJECTIVES: To assess the ability of the pain drawing to predict the presence of nerve root compression. SUMMARY OF BACKGROUND DATA: Most research work has concentrated on the ability of the pain drawing to act as a screening method for psychological distress with less work directed at the influence the anatomic abnormality has on the pain drawing. METHODS: One hundred thirty-four consecutive outpatients attending for lumbar magnetic resonance imaging in the investigation of back and leg pain completed pain drawings and psychological testing immediately before the examination. The pain drawing was analyzed by previously reported criteria, and the magnetic resonance imaging was assessed independently for the presence of nerve compression by three radiologists. Multivariate stepwise discriminant analysis was used to identify patients with nerve compression on the basis of their pain drawing. RESULTS: Nerve compression was predicted by numbness in the anterolateral aspect of the foot. There was considerable overlap in the appearances of the pain drawings between patients with and without nerve compression, and the pain drawing correctly classified only 58% of patients with nerve compression. CONCLUSIONS: The pain drawing is not a good predictor of nerve compression on magnetic resonance imaging in a group of patients investigated for back and leg pain. It should be interpreted with caution and in light of the full clinical picture.

Adult↗

Potential usefulness of 18F-2-fluoro-deoxy-D-glucose positron emission tomography in cervical compressive myelopathy.

STUDY DESIGN: This case study describes the usefulness of high-resolution 18F-2-fluoro-deoxy-D-glucose (18FDG)-positron emission tomography (PET) for metabolic neuroimaging of the cervical spinal cord in patients with compressive myelopathy. OBJECTIVE: To examine whether 18FDG-PET imaging could visualize deterioration of cervical spinal cord function associated with a variable degree of compression and to determine its potential usefulness during assessment of myelopathy. SUMMARY OF BACKGROUND DATA: A few studies have described the use of 18FDG-PET imaging in cervical cord diseases, but visualization of the cervical spinal cord before and after surgical decompression for compressive myelopathy has not been reported. The potential usefulness of 18FDG-PET imaging for assessment of the function of compressed cervical cord has not been discussed previously. METHODS: An 18FDG-PET scan was performed before and after surgery in seven patients with cervical compressive myelopathy. The correlation between the metabolic rate of glucose of the cervical spinal cord and neurologic scores was evaluated. The metabolic rate of glucose in different vertebral levels was also measured. RESULTS: Preoperative metabolic rate of glucose was high in two patients but low in the other five. At the time of the second postoperative examination, metabolic rate of glucose was higher in six of the seven patients, and the increase was associated with neurologic improvement. Use of 18FDG was not related to changes in signal intensities on T2-weighted magnetic resonance images. The metabolic rate of glucose decreased at the affected vertebral level in four patients, increased in two, and did not change in one, relative to the unaffected levels. CONCLUSIONS: High-resolution 18FDG-PET neuroimaging may provide clinically useful qualitative and quantitative estimation of impaired metabolic activity of the compromised cervical spinal cord in compressive myelopathy. 18FDG-PET images may also offer additional information related to neuronal dysfunction induced by mechanical compression.

Adult↗