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PubMed1990

[An experimental study on compression neuropathy--the vulnerability of the peripheral nerve associated with pregnancy].

The carpal tunnel syndrome often occurs in women associated with pregnancy and menopause, but its pathophysiology is not well understood. The author proposes a hypothesis that the peripheral nerve is vulnerable in pregnancy to become an important cause for the carpal tunnel syndrome. This study was designed to test the hypothesis by using "Keio compression device" for sciatic nerve of a dog using the compression force of 27.6 mmHg/cm2. No remarkable changes were found in the pregnant group before compression. In the control group, a delay of motor nerve conduction velocity was seen three weeks after compression. In contrast, the conduction block at compression site occurred in more than half of pregnant group under an equal compression force, inducing severe histological changes. This study demonstrates an increase of the vulnerability of the peripheral nerve in pregnancy. A disturbance of the blood-nerve barrier as well as the changes of hormones and vitamins could influence this phenomenon.

Animals↗

PubMed1988

[Radiological diagnosis of chronic spinal cord compressive lesion at thoraco-lumbar junction].

Radiological findings in five cases with chronic spinal cord compressive lesion at thoraco-lumbar junction were reported. Three cases had spondylosis and two cases had ossification of yellow ligament (OYL). The levels of the lesions were T12/L1 in three cases and T11/12 in two cases. Two out of three spondylotic patients had also OYL at the same level. The five cases consisted of three men and two women. The ages ranged from 42 to 60 years old with a mean age of 53 years old. Neurologically, every patient showed flaccid paresis and sensory disturbance of the legs. Two cases had sensory disturbance of stocking type. The intervals from the onset of the symptoms to the final diagnosis were 6 months, 7 years, 8 years, 11 years and 12 years. Myelography showed anterior spinal cord compression by bony spur in spondylotic patients, and posterior compression by OYL in other cases. Myelography in flexion posture disclosed the cord compression by bony spur more clearly in two out of three spondylotic patients. Delayed CT-myelography showed intramedullary filling of contrast material in two cases, which indicated degenerative change or microcavitation due to long term compression of the spinal cord. MRI was taken in three spondylotic patients and could directly show compression of the spinal cord. Difficulty in detecting abnormality at thoraco-lumbar junction on plain roentgenogram, and similarity of the symptoms to peripheral nerve disease often lead to a delay in diagnosis. The significance of dynamic myelography and delayed CT-myelography when dealing with such a lesion was discussed here.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Late compression neuropathies after Colles' fractures.

Conservative management of 166 Colles' fractures was associated with a 12% rate of late compression neuropathies (mean follow-up period, 28 months). Compression of the median nerve (8%) was twice as common as ulnar nerve compression (4%). Eighty-five percent of the patients with median nerve compression had malunion with radial collapse with or without other deformities (dorsal angulation/radial displacement). Patients with ulnar nerve compression had either malunion with radial collapse or volar subluxation of the ulnar head in those fractures that healed with dorsal angulation. Patients without nerve complications showed a significantly lower rate of malunions. These results demonstrate that anatomic derangements play a role in the development of late compression neuropathies following Colles' fractures.

Adolescent↗

PubMed1984

[Unilateral visual field defect due to optic nerve compression by non-sclerotic internal carotid and ophthalmic arteries. A case report].

A case of unilateral visual field defect due to optic nerve compression by non-sclerotic internal carotid and ophthalmic arteries was reported. A 14-year-old boy was admitted to our department because of constricted visual field of the right eye. The right ophthalmic artery originated from more distal portion of the internal carotid artery than usual on angiogram. CT, PEG and other roentgenologic examinations revealed no abnormalities. But the possibility of para-sellar tumor still remained, so the right optic nerve was explored by a right frontotemporal approach. The optic nerve was found to be compressed not by any sort of mass lesion but by the non-sclerotic internal carotid and ophthalmic arteries against the rim of the optic canal. Then a microsurgical unroofing of the optic canal was performed to relieve the nerve from the compression. The decompressed upper surface of the nerve was found to be discolored yellow-white. Unfortunately, no improvement in the visual field was obtained after operation. Visual field defect due to vascular compression of the optic nerve has been discussed in only several reports. There have been only 8 cases of surgically treated unilateral visual field defect due to vascular compression. Most of them were the results of compression by the sclerotic or fusiformly enlarged internal carotid arteries and were found in the patients of middle age. Four cases presented with lower half visual field defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1984

[Spinal cord compression in multiple myeloma. Study of 10 cases].

Ten cases of multiple myeloma with spinal cord compression are reported. The compression was located in the thoracic spine in 9 cases and in the cervical spine in 1 case. It led to the discovery of the myeloma in 4 cases. Three patients suffered, during several months, from local pain aggravated by activity and from slight and slowly progressive neurologic symptoms resembling intermittent claudication. At the time of diagnosis, sphincter dysfunction was observed only in patients with low thoracic cord compressions. In 4 cases, lesions were first treated by radiotherapy which did not produce regression of the compression. Tumor excision surgery was carried out seven times, once after failure of radiotherapy. In 6 cases an definite and steady regression of the neurological symptoms was achieved. Survival varied from 10 months to 7.5 years after identification of spinal cord compression. Survival was equal to or more than 3 years in 4 patients and will probably reach 3 years in another. Thus spinal cord compression is not by itself a sign indicating a poor short term prognosis in multiple myeloma. It should be treated by excision surgery, then by chemotherapy as in multiple myeloma at other sites.

Aged↗

PubMed1995

[Pathogenesis of acute and chronic compression neuropathy].

The purpose of this study was to clarify the morphological changes in the cell body following acute, and chronic, nerve compression injuries. One hundred and fifty-eight adult male Wistar rats were used for the experiments. Acute compression was produced by clamping the sciatic nerve (ca. 1.3 mm diameter) using a stainless steel Micro-Tube-Clamp (1.6 mm-width and an internal diameter of 1.0 mm). To produce chronic entrapment neuropathy, we used Mackinnon-Dellon's procedure, in which a 1.0 cm length of Silastic tube with an internal diameter of 1.51 mm was wrapped around the nerve trunk. The morphological and functional changes in the nerve trunks were then studied. Histological examinations and morphometric measurements of the nerve cell bodies in the L5 dorsal root ganglion were also carried out for up to 15 months after the procedure. Degeneration of large myelinated nerve fibers, interfascicular edema, interruption of the blood-nerve barrier and a delay in the fast orthodromic axonal transport were found as early as 1 day after clamping, a decreased in the motor nerve conduction velocity on the third day, and a thickening in the perineurium after 1 week. In the chronic experiment, these changes were found at 4, 4, 2, 8, 8, and at 2 months after wrapping, respectively. A significant change in the nuclear eccentricity was morphometrically discovered in both types of nerve compressions-on the third day after clamping, and at 6 months after wrapping. In addition, dispersion of Nissl substance, dislocation of cell organelles and an increase in the number of cytoskeletons were observed in the somata. Acute and chronic nerve compression induced morphologic changes in the nerve cell body as well as in the peripheral nerve fibers. These findings suggested that compression of the peripheral nerve fiber changed the metabolic activity of the nerve cell body. We concluded that compression neuropathy affected the whole neuron including the nerve cell body.

Acute Disease↗

PubMed1995

[A chronic spinal cord compression model in a rat with a 354A tumor].

A posterior spinal cord compression model was produced in a rat with a 354 A tumor. Here we report the compression process using MRI (at 2.11 tesla), the progression of paralysis in the posterior limbs, the pathological changes in the neural tissues, and the spinal evoked potentials (SpEPs). A relatively flat spinal cord compression model was established by the interposition of free fatty tissue between the tumor and dura mater. The anteroposterior diameter of the compressed cord (AP), the width of the compressed cord (W), the cross-sectional areas of the spine (A), the mean of the anteroposterior diameters of the cord at the levels of the adjacent cephalic and caudal vertebral bodies (AP), and the mean of the cross-sectional areas of the cord at the levels of the adjacent cephalic and caudal vertebral bodies (A) were measured on axial views from MRI. Paralysis of the posterior limbs occurred in this model when A/A became less than 60%, AP/AP became less than 35% and AP/W became less than 20%. Pathological changes became apparent in the neural tissues when A/A became less than 50-60%, AP/AP became less than 25-30% and AP/W became less than 15%. Polyphasic wave-forms were noted when A/A became less than 60%, AP/AP became less than 35% and AP/W became less than 20%. When the A/A became less than 40%, the histopathological changes became marked. SpEPs could no longer be detected at this degree of compression, indicating that all neural conduction had been blocked.

Animals↗

PubMedDate not supplied

The surgical treatment of spinal cord compression caused by tumorous metastases. A review of 91 cases.

Spinal cord compressions as a result of metastases are of considerable importance with regard to the quality of life and life expectancy of the cancer patient. Although surgical treatment has contributed to a considerable improvement in the life conditions of these patients, some questions still exist, particularly with regard to the choice of the time to operate. Thus, a total of 91 patients submitted to decompression were studied, taking into consideration different factors such as anatomo-radiographic findings, temporal parameters regarding occurrence of compression, and relative neurologic findings. Compression was incomplete in 44% of cases, complete in 45%, and complete with vertebral collapse in only 11%. Furthermore, it was observed that the group with partial compression included the lowest percentage of patients who resumed walking (57.5%), as compared to those with complete block (65.85%), or complete block associated with vertebral collapse (70%). This contradiction is confirmed by the observation that the resumption of walking was longer in cases with total block as compared to those with partial block. These results, apparently paradoxical ones, may be explained on the basis of the different duration of compression in the two groups. In fact, if we analyze the data relative to the interval of time between the occurrence of neurologic symptoms and surgery, we observed that patients with partial block were those in which surgical indications were made a longer period of time after the onset of symptoms. Surgical indications must be made at the first sign of deficit, regardless of the degree of compression present in the radiologic documentation, in order to avoid the transformation of reversible functional medullary changes into irreversible structural lesions.

Adolescent↗

PubMed2006

Vertebral artery compression of the medulla.

BACKGROUND: Intracranial arteries in the subarachnoid space may compress the brain parenchyma and cranial nerves. Most arterial compressive lesions have been attributed to dolichoectasia in the vertebral-basilar system, and prior reports have concentrated on the pressure effects of basilar artery ectasia. Much less is known about vertebral artery compression of the medulla. OBJECTIVE: To describe a series of patients with vertebral arteries compressing the medulla oblongata. DESIGN: Prospective case studies. SETTING: Tertiary care center. PATIENTS: Nine symptomatic patients, 4 men and 5 women, between the ages of 32 and 79 years. MAIN OUTCOME MEASURES: Clinical phenomena, radiographic findings, treatment, and outcomes. RESULTS: We found that compression most commonly occurs at the ventrolateral surface. The clinical features can be transient or permanent and are predominantly motor and cerebellar or vestibular, but a poor correlation exists between the clinical findings and the severity or extent of impingement. The vertebral arteries were angulated, tortuous, or dilated but not necessarily dolichoectatic to cause obvious indentation. Seven patients were treated with antiplatelets and anticoagulants or analgesics, whereas 2 underwent microvascular decompression, resulting in temporary or no relief. One surgical patient developed cranial nerve complications. Among the medically treated patients, none had progression of deficits, and those with single episodes had no recurrence of symptoms. CONCLUSION: This study is the largest collection, to our knowledge, of patients with medullary vascular compression. Further studies are needed to estimate its frequency, natural course, and preferred management.

Adult↗

PubMed2001

Limb salvage using high-pressure intermittent compression arterial assist device in cases unsuitable for surgical revascularization.

HYPOTHESIS: Intermittent compression therapy for patients with inoperable chronic critical ischemia with rest pain or tissue loss may have beneficial clinical and hemodynamic effects. STUDY DESIGN: Case series of 14 consecutive ischemic legs that underwent application of a 3-month treatment protocol during a 2(1/2)-year study. SETTING: Veterans Administration Hospital. PATIENTS: Thirteen patients with 14 critically ischemic legs (rest pain, n = 14; tissue loss, n = 13) who were not candidates for surgical reconstruction were treated with rapid high-pressure intermittent compression. The patients had a mean age of 76.2 years, 8 were diabetic, and they represented 10% of referrals for chronic critical ischemia. They were not amenable to revascularization owing to lack of outflow arteries (n = 7), lack of autogenous vein (n = 5), or poor general medical condition (n = 3). INTERVENTION: All patients were instructed to use the arterial assist device for 4 hours a day at home for a 3-month period. MAIN OUTCOME MEASURES: Limb salvage and calibrated pulse volume amplitude. RESULTS: After 3 months, 9 legs had a significant increase in pulse-volume amplitude (P< .05). These legs were salvaged, whereas the 4 amputated legs demonstrated no hemodynamic improvement. We noted a direct correlation between patient compliance and clinical outcome. Patients in whom limb salvage was achieved used their compression device for longer periods of time (mean time, 2.38 hours a day) compared with those who underwent amputation (mean time, 1.14 hours a day) (P< .05). These mean hours of use were derived from an hour counter built into the compression units. CONCLUSIONS: Intermittent high-pressure compression may allow limb salvage in patients with limb-threatening ischemia who are not candidates for revascularization. Further studies are warranted to assess intermittent compression as an alternative to amputation in an increasingly older patient population.

Aged↗

PubMed2005

Surgical management of multinodular goiter with compression symptoms.

HYPOTHESIS: Multinodular goiter (MG) with compression symptoms has a clinical profile different from that of goiter without these symptoms. The surgical treatment of MG with compression symptoms has a high rate of sternotomy and morbidity. DESIGN: Retrospective study conducted between 1970 and 1999. SETTING: Tertiary referral center. PATIENTS: One hundred fifty-seven patients with MG with compression symptoms were reviewed from 672 patients with MG undergoing surgery in our department. We used 515 patients with MG without compression symptoms as a control group. INTERVENTION: All 157 patients underwent programmed surgery for thyroidectomy. MAIN OUTCOME MEASURES: General patient data, history and symptoms, exploration (both physical and with complementary techniques), data on the surgery and surgeon, and postsurgery morbidity and evolution. The chi2 test, the t test, and a logistic regression test were applied. RESULTS: Multinodular goiter with compression symptoms is characterized by its appearance in persons older than 55 years, a preoperative evolution of more than 10 years, and an intrathoracic component in more than 75% (P<.001). All the patients underwent surgery, with 6 (4%) requiring a sternotomy. Twenty-four percent had complications (n = 37), 3% of which corresponded to 4 cases of permanent recurrent laryngeal nerve injury. Eleven patients (7%) had an associated thyroid carcinoma, 9 of them corresponding to microcarcinomas. However, 5 were multifocal, and there was 1 anaplastic carcinoma, from which the patient died. All the papillary carcinomas are currently asymptomatic. The symptoms were remitted after surgery in all the cases except 1 dysphonia. Of the 32 patients receiving partial surgery, 9 (28%) had recurrence, of whom 6 underwent reoperation to complete the thyroidectomy. CONCLUSIONS: Multinodular goiter with compression symptoms occurs in long-evolving goiters with an intrathoracic component. Surgery is the definitive treatment, as it excludes malignancy, involves low rates of permanent morbidity and mortality, and, if the technique is total thyroidectomy, avoids recurrences.

Chi-Square Distribution↗

PubMed1975

Type of compression for reducing venous stasis. A study of lower extremities during inactive recumbency.

Determination of the optimal compression to reduce venous stasis was studied in terms of the amount of pressure and manner of application (graded or uniform pressure). Both lower extremities of seven inactive recumbent subjects were tested using transcutaneous Doppler ultrasonic measurement of femoral vein blood flow velocity. Optimal compression was defined as the externally applied pressure that produced the greatest increase in femoral vein flow velocity consistent with safety and the practicality of hospital use of elastic stockings. Optimal compression for elastic stockings to be used by hospitalized patients who spend substantial time in bed should be 18 to 8 mm Hg (ankle to midthigh). At this compression, average femoral vein blood flow velocity is increased to 138.4% of base line. Gradient compression at this level was found to produce a greater femoral vein flow velocity than the same amount of compression distributed uniformly over the lower extremity.

Adult↗

PubMed1996

Telesurgery. Acceptability of compressed video for remote surgical proctoring.

OBJECTIVE: To determine the clinical acceptability of various levels of video compression for remote proctoring of laparoscopic surgical procedures. DESIGN: Observational, controlled study. SETTING: Community-based teaching hospital. PARTICIPANTS: Physician and nurse observers. INTERVENTIONS: Controlled surgical video scenes were subjected to various levels of data compression for digital transmission and display and shown to participant observers. MAIN OUTCOME MEASURES: Clinical acceptability of video scenes after application of video compression. RESULTS: Clinically acceptable video compression was achieved with a 1.25-megabit/second data rate, with the use of odd-screen 43.3:1 Joint Photographic Expert Group compression and a small screen for remote viewing. CONCLUSION: With proper video compression, remote proctoring of laparoscopic procedures may be performed with standard 1.5-megabit/second telecommunication data lines and services.

Adult↗

PubMed1999

Sodium and proton MR properties of cartilage during compression.

Proton and sodium MR relaxation times of bovine articular cartilage specimens were measured as a function of proteoglycan (PG) depletion and as a function of mechanical compression. Proton and sodium relaxation times of normal cartilage were compared with relaxation times of PG-depleted cartilage to evaluate the significance of PG depletion-induced changes in MR relaxation parameters. These comparisons were conducted for both uncompressed and mechanically compressed states. The mechanical compressions were performed with an MR-compatible pressure cell and evaluated dynamically via interleaved one-dimensional proton and sodium MR projection imaging. The comparisons indicate that sodium relaxation parameters are sensitive to PG depletion when cartilage is in a mechanically compressed state or an uncompressed state. In contrast, proton relaxation parameters do not change significantly with PG depletion when cartilage is in an uncompressed state. However, during mechanical compression, proton T2 becomes sensitive to PG depletion. These results support the potential of sodium magnetic resonance imaging (MRI) as a possible modality for obtaining imaging contrast related to PG depletion. The results also indicate the potential of proton MRI to provide such contrast if the image acquisition is conducted in conjunction with a mechanical compression via physical exercise.J. Magn. Reson Imaging 10:961-967, 1999.

Animals↗

PubMed2000

Toxicity effects of compressed and supercritical solvents on thermophilic microbial metabolism.

Selection of biocompatible solvents is critical when designing bioprocessing applications for the in situ biphasic extraction of metabolic end-products. The prediction of the biocompatibility of supercritical and compressed solvents is more complicated than for liquid solvents, because their properties can change significantly with pressure and temperature. The activity of the anaerobic thermophilic bacterium, Clostridium thermocellum, was studied when the organism was incubated in the presence of compressed nitrogen, ethane, and propane at 333 K and multiple pressures. The metabolic activity of the organisms in contact with compressed solvents was analyzed using traditional indicators of solvent biocompatibility, such as log P, interfacial tension, and solvent density. The toxicity of the compressed solvents was compared with the phase and molecular toxicity effects measured in liquid alkanes at atmospheric pressure. Inactivation increased with time in the presence of the compressed solvents, but was constant in the presence of atmospheric liquid solvents. Knowledge of molecular and phase toxicity provides a framework for the interpretation of C. thermocellum metabolism in contact with atmospheric and compressed solvents.

Clostridium↗

PubMed1980

A physiological study of elastic compression stockings in venous disorders of the leg.

The physiological effects of elastic compression stockings on venous disorders of the leg have been studied in three groups of 10 patients. These patients were divided by examination and ascending venography into those with: (a) a normal venous system in the leg, (b) superficial varicose veins and (c) a post-phlebitic limb. In a randomized cross-over trial each groups wore Eesiness NHS two-way stretch or Sigvaris medium compression below-knee stockings for three weeks. In the post-phlebitic limb group a further comparison was made with Sigvaris strong compression below-knee stockings after a 6-week rest period. The effects were objectively compared using foot volumetry and sodium (24Na) subcutaneous tissue clearance. The physiological benefits of Sigvaris medium and strong compression stockings were comprehensively demonstrated by both methods of assessment in patients with the post-phlebitic limb. Benefit from Sigvaris medium compression stockings was also demonstrated in the patients with varicose veins. In the group with normal veins there were negligible physiological benefits from compression stockings. Eesiness stockings failed to produce a significant physiological effect in each group.

Clothing↗

PubMed1989

Fracture behavior of urinary stones under compression.

The fracture behavior of two types of urinary stones, namely struvite and calcium oxalate, during compression testing was studied. Scanning electron microscopy (SEM) was used to characterize the fracture surfaces. Both types of stone showed pseudo-plastic behavior as indicated by their load-displacement curve. The onset of nonlinear behavior was found to correspond to development of microcracks in the specimens. The compressive strength was defined as the stress calculated at the maximum load. In struvite samples, the maximum load corresponded with the development of large cracks parallel to the compressive axis. For oxalate stones a separation of the outer layer (crust) from the inner layer (core) marked the point of maximum load. The compressive strength of the struvite samples was found to depend on the orientation of lamellae relative to the loading axis. Struvite stones, when loaded parallel to the lamination direction showed a higher compressive strength than oxalate stones did. The fracture behavior and compressive strength of a model material (z-brick) were also characterized and compared to those of the urinary stones.

Lithotripsy↗

PubMed2002

Blood perfusion of vertebral lesions evaluated with gadolinium-enhanced dynamic MRI: in comparison with compression fracture and metastasis.

PURPOSE: To investigate blood perfusion of vertebral lesions using dynamic Gd-DTPA-enhanced MRI. MATERIALS AND METHODS: Dynamic MR studies were performed for cases of acute compression fracture, chronic compression fracture, metastatic vertebral lesions with or without compression fracture. A total of 42 patients (71 vertebral segments) were included. Five types of time-intensity curves (TICs) were defined as: nearly no enhancement (type A), slow enhancement (type B), a rapid contrast wash-in followed by an equilibrium phase (type C), a rapid contrast wash-in followed by early wash-out (type D), and a rapid contrast wash-in with a second slower-rising slope (type E). RESULTS: Metastatic vertebral lesions with or without fracture had a higher peak enhancement percentage and steeper enhancement slope than those of chronic compression fracture, but had no difference as compared to those of acute compression fracture. The type D curve had high positive predictive value for metastatic group (100%), and the type E curve had high positive predictive value for benign compression fracture (85.7%). CONCLUSION: Type D and E curves are valuable in the differentiation of benign and malignant vertebral lesions.

Adult↗