Biomedical subjects

S M Iencean

Publications and source records attributed to S M Iencean.

9 recordsLinked to original sources

PubMed2003

Brain edema -- a new classification.

Brain edema is a reaction to any brain injury and can be the first stage in the beginning of intracranial hypertension. This paper puts forth a modern classification of brain edema types, based on a etiopathogenic interpretation. The hydroelectrolitic and/or proteinic buildup can occur within cells and/or in the extracellular space and differentiates three types of brain edema: cellular brain edema; extracellular brain edema and combined brain edema. Cellular brain edema (cytotoxic brain edema) occurs through intracellular hyperosmolarity or extracellular hypotonicity. Extracellular brain edema (interstitial) appears as a result of the buildup of edema fluid in the extracellular space of the brain parenchyma and can be: hydrostatic extracellular brain edema (through ultrafiltration), oncotical extracellular brain edema (vasogen brain edema) and hydrocephalic extracellular brain edema. Combined brain edema includes in variable ratios both types of brain edema, cellular and extracellular; they can be present together from the beginning or can appear successively.

Animals↗

PubMed2003

Classification of spinal injuries based on the essential traumatic spinal mechanisms.

STUDY DESIGN: A biomechanical unitary classification of spinal injuries is proposed. OBJECTIVE: To present an evaluation of spinal injuries based on the essential traumatic spinal mechanisms: axial deformation, torsion, translation and combined mechanisms in connection with the concept of the stabilizing axial spinal pillar. SETTING: Hospital 'Sf. Treime', Iasi, Romania. METHODS: The essential mechanisms of spinal injuries are considered: (1) axial deformation with (a) compression (centric or eccentric), most often eccentric, including compression in flexion or extension; (b) spinal elongation with distraction as centric elongation, but frequently axial eccentric elongation and a flexion or extension injury; (2) torsion or axial spinal rotation, (3) segmental translation, with a shearing version for the double translation and (4) combined mechanisms - the most frequent situation. Over 300 patients with spinal injuries were analysed and the spinal instability was determined using the criteria of clinical instability. The cases of spinal instability were studied in connection with the types of lesion of the central axial spinal pillar. RESULTS: All cases with lesions of the central axial spinal pillar had traumatic spinal instability. The spinal instability was absent in cases of isolated lesions of the anterior or posterior secondary pillar. The X-ray and spinal CT analysis of the traumatic spinal lesions showed the types of lesions and specified the mechanisms of spinal injuries. The combined mechanisms were responsible for the majority of the spinal injuries. CONCLUSIONS: Spinal instability occurs because of the lesion of the central axial spinal pillar The types of lesions of the central spinal pillar and of the secondary spinal pillars are determined by the essential traumatic spinal mechanisms: axial deformation (with compression or elongation), axial rotation, translation and most frequently the above combined mechanisms.

Diagnosis, Differential↗

PubMed2002

Double noncontiguous cervical spinal injuries.

BACKGROUND: Double noncontiguous spinal injuries in the same patient, the first at the cervical level and the second at the thoracic or thoracolumbar level are not uncommon. On the other hand the incidence of double noncontiguous cervical injuries in low and these injuries imply complex mechanisms. This study investigates the cases of double noncontiguous cervical lesions in 342 cases of acute cervical injuries. METHOD: An analysis of 342 patients with cervical injuries found 67 multiple cervical injuries and only 11 cases of double noncontiguous cervical lesions. FINDINGS AND INTERPRETATION: Double noncontiguous cervical injuries have a frequency of 3.2% in this study and in three cases there were pre-existing benign cervical lesions. A possible spinal biomechanical behaviour during injury can be that the first lesion appears because of the traumatic impact and there is a uniform transmission of the remaining traumatic strain all along the spine. It seems that the propagated force finds a spinal zone where the spinal resistance is diminished and the second spinal lesion can occur. Spinal vulnerability for the second lesion in the same trauma can be caused by a pre-existing benign spinal lesion or by a biomechanical discontinuity because of a particular posture at the traumatic moment. The second lesion in double noncontiguous cervical lesions can appear through a single great impact in pre-existing lesions, double impacts at the same time with injuries at two cervical levels or repeated cervical impacts in very quick succession in the same trauma.

Adolescent↗

PubMed2002

The stabilizing axial spinal pillar in the lumbar spine.

STUDY DESIGN: A theoretical model of spinal stability is proposed. OBJECTIVE: To present a biomechanical study in vitro using flexibility and loading tests of the normal lumbar spine and of two lumbar models of spinal stability in order to determine which of the lumbar middle-column model and the personal suggested model of lumbar central axial pillar is more resistant and stable. SETTING: Hospital 'Sf.Treime', Iasi, Romania. METHODS: Twenty-three fresh human cadaveric lumbar spines were tested with flexibility and loading tests of the intact lumbar functional units and of two types of spinal model specimens: 10 lumbar middle-column models and 13 lumbar central pillar model specimens. Parameters of vertebral motion and vertebral compression were compared to determine the differences between the types of spinal models. RESULTS: The flexibility tests show a significant increase in motion of the lumbar middle-column model specimens compared to the lumbar central pillar model specimens. The lumbar central pillar model specimens are three times more stable compared to the middle-column models. The compression tests show that the lumbar central axial pillar model specimens were more resistant, on average by 10% (30% maximum) compared to the other model. CONCLUSIONS: The lumbar model formed by the axial overlapping of the posterior half moon of vertebral body continued by the pedicles and the articular processes is more stable and more resistant compared to the middle-column model of the three-columns theory of Denis. In the lumbar spine this central axis spinal pillar is the structure of spinal stability and resistance, and I propose this central axial spinal pillar as the stabilizing structure for all the spine.

Adult↗

PubMed2002

A new classification and a synergetical pattern in intracranial hypertension.

Intracranial hypertension develops from the initial cerebral effect of increased intracranial pressure and becomes symptomatical; then it acquires its individuality, surpassing the initial disease. The intracranial hypertension syndrome corresponds to the stage at which the increases in intracranial pressure (ICP) can be compensated and the ICH disease is in its acute form, equivalent to a decompensated ICH syndrome. Based on the etiopathogenesis of intracranial hypertension, a new classification is proposed: parenchymatous intracranial hypertension with an intrinsic cerebral cause; vascular intracranial hypertension, which has its etiology in disorders of the cerebral blood circulation; and essential or idiopathic intracranial hypertension, the former pseudotumor cerebri, an incomplete ICH syndrome. A synergetical pattern of the ICH is based on the relation between ICP and the period of high-pressure action: the critical pressure--time fluctuation causes the autoregulation of the cerebral blood flow to decrease or determines the brain herniation. The decompensation is a state of instability and appears when the intrinsic ratio of pressure--time fluctuation is changed: the high ICP lasts longer than the corresponding normal ICP, or the ICP is higher than the one that normally lasts the same period of time.

Cerebrovascular Circulation↗

PubMed2000

Lumbar intervertebral disc herniation following experimental intradiscal pressure increase.

An experimental biomechanical model of overload and rupture of the annulus fibrosus (AF) and lumbar disc herniation was achieved by increasing intradiscal pressure while keeping disc height constant in 69 motion segments at the L4-L5 level excised from cadaveric spines. The experiments were made on 53 specimens in neutral posture and on 16 specimens in flexion posture. The values found for the rupture intradiscal pressure (RIP) ranged from 750 to 1300 kPa for neutral posture and the maximum RIP in anterior flexion was 1177 kPa. The degree of disc degeneration was assessed by vertebral transcorporeal discography (previous to experiment) and by sectioning the intervertebral disc after the experiment. The herniated lumbar intervertebral disc model by intradiscal pressure increase makes possible these assertions: * The correlation between the degree of AF degeneration and the RIP is significant: the maximum RIP corresponds to a non-degenerated AF and the less RIP can tear only a degenerated AF; so disc herniation only occurs to discs with torn AF. * AF breaking is more often paramedian, left or right. The place of AF breaking was paramedian in 70.3% cases, median in 9.45% cases and posterolateral in 20.25% cases.

Adult↗

PubMedDate not supplied

Idiopathic intracranial hypertension and idiopathic normal pressure hydrocephalus: diseases with opposite pathogenesis?

Idiopathic intracranial hypertension (IDICH) and idiopathic normal pressure hydrocephalus (IDNPH) are disorders of the circulation of the cerebrospinal fluid (CSF) with opposite diagnostic features, obscure etiology but the same treatment: CSF drainage. In both diseases a large quantity of CSF exists: equilibrated by the brain edema in IdICH with high ICP and not equilibrated by brain pressure, and the ventricles are enlarged in IdNPH. The same anatomical structure involved in both diseases is the ventricular wall and this represents a true barrier, a glial-ependymal barrier and it acts as a barrier only in connection with the difference between the pressures. The spontaneous course of both diseases suggests that an open glial-ependymal barrier protects the brain parenchyma.

Brain↗

PubMedDate not supplied

Simultaneous hypersecretion of CSF and of brain interstitial fluid causes idiopathic intracranial hypertension.

Idiopathic intracranial hypertension (IdICH) is a high intracranial pressure and no evidence of intracranial lesions or hydrocephalus. The characteristics of IdICH and the anatomical and physiological data show that the mechanisms of elaboration of the interstitial fluid at blood-brain barrier (BBB) and of cerebrospinal fluid (CSF) at choroid plexus are very similarly. In IdICH many pathological conditions can induce the simultaneous hypersecretion of CSF and of the brain interstitial fluid and the high intracranial pressure (ICP) of CSF is equalized simultaneously of the pressure of the brain interstitial fluid. The cerebral blood flow is maintained quasinormal in IdICH, even increased, so that it occurs a fast absorption of CSF and of interstitial fluid and the brain injury is insignificantly despite the high ICP. Therefore idiopathic intracranial hypertension occurs through simultaneous hypersecretion of the cerebrospinal fluid and of the cerbral interstitial fluid followed by a rapid circulation and absorption of these fluids based on a fast cerebral blood flow.

Blood-Brain Barrier↗

PubMedDate not supplied

Laminoplasty--the surgical treatment of the cervical spondylotic radiculopathy.

The present surgical treatment of the cervical spondylotic myelopathy and radiculopathy consist in cervical laminoplasty. The cervical laminoplasty has many variants since it was first proposed in the 1968's. It is presented a variant simplified of the Hirabayashi's technique of laminoplasty, used to the patients with unilateral cervical radiculopathy and it is proposed a technique of "bilateral laminoplasty" using iliac bone graft stabilized with transfixed wire. This technique is simple and permits a bilateral nerve roots decompression.

Bone Transplantation↗