Peripheral nerve elongation by laser Doppler flowmetry-monitored expansion: an experimental basis for future application in the management of peripheral nerve defects.

Nerve grafting often fails to achieve optimal functional results and is always associated with donor-site morbidity. Peripheral nerve elongation by the use of a tissue expander may provide a useful adjunct in the management of segmental nerve loss. In the present study, rabbit sciatic nerve (n = 40) was elongated by expansion while nerve blood flow was monitored by laser Doppler flowmetry. Elongation was possible up to 40 percent with preservation of clinical nerve function. Nerve conduction velocity of the expanded nerves decreased in a linear relation to elongation. The reduction in nerve conduction velocity may be secondary to the observed widening of the nodes of Ranvier and altered membrane properties after remyelination. Demyelination and remyelination of whole internodes and axonal degeneration occurred only sporadically. Thus laser Doppler flowmetry-monitored expansion provides a safe method for elongation of intact rabbit sciatic nerve while nerve function and axonal continuity are preserved. Further studies are needed before clinical use is considered. This technique may represent a favorable alternative to nerve grafting for the treatment of peripheral nerve defects.

Operative treatment of meralgia paresthetica: transection versus neurolysis.

The question of the superior operative technique for meralgia paresthetica is unsettled. Operative treatment by either neurolysis or transection of the lateral femoral cutaneous nerve was performed in 21 patients with meralgia paresthetica after complete failure of conservative treatment; neurolysis in 10 patients and transection in 11 patients were performed by five neurosurgeons. The average follow-up period was 74 months (+/- 52 mo). The results were scored as complete relief, partial relief, or failure. Direct comparison of neurolysis and transection confirmed the superiority of transection as a treatment for meralgia paresthetica (Mann-Whitney-U test, P = 0.022; one-sample sign test, P = 0.0020).

Peripheral nerve elongation by laser Doppler flowmetry controlled expansion: morphological aspects.

Peripheral nerve elongation by a tissue expander may offer an alternative to nerve grafting in the management of segmental nerve loss. We investigated the morphological changes in peripheral nerve following slow nerve elongation by laser Doppler flowmetry controlled expansion in a rabbit sciatic nerve model. The animals were randomly assigned to one of four groups, with an expander volume of 0, 5, 10 or 15 cm3, respectively. An elongation of up to 40% was possible with preservation of clinical function. Nerve conduction velocity decreased in relation to elongation. Paranodal widening, followed by remyelination of the node, were early and constant morphological features. Demyelination and remyelination of whole internodes, and axonal degeneration occurred sporadically and did not correlate with elongation, rate of elongation or neurophysiological parameters. The model of laser Doppler flowmetry controlled nerve expansion provides a method for remodelling of myelin sheaths and lengthening of nerve fibers without axonal damage.

Peripheral nerve elongation by laser Doppler flowmetry controlled expansion: functional and neurophysiological aspects.

A new method for elongation of peripheral nerves with preservation of function is presented. Nerve blood flow during experimental nerve expansion of rabbit sciatic nerve is controlled by laser Doppler flowmetry in order to avoid nerve ischemia. Using this method, nerve function in relation to gait remained intact in 72.5% of the animals and recovered within 3 weeks in the others. Disturbances in toe-spread reflex recovered completely in all animals after 3 weeks. Significant nerve elongation up to 40% is possible with preservation of function when nerve blood flow is controlled by laser Doppler flowmetry.

A model for monitoring nerve blood flow during expansion by laser Doppler flowmetry in the rabbit.

A new model is described for monitoring nerve blood flow during expansion by laser Doppler flowmetry. Rabbit sciatic nerve is gradually expanded with a custom-made spherical expander, while nerve blood flow is monitored by laser Doppler flow output. This model provides a valid method of controlling nerve blood flow during expansion.

Multiple brain abscesses and bacteremia in a child due to Fusobacterium necrophorum.

A case of Fusobacterium necrophorum bacteremia and multiple brain abscesses in a 6-year-old child following a Mycoplasma pneumoniae infection is described. Brain abscess due to this microorganism has only been described in three other cases since 1977. The clinical picture was consistent with postanginal septicemia, with septic metastatic complications normally only seen in teenagers and young adults. The patient was successfully treated with a 2-month course of parenteral penicillin G and metronidazole.

Salvage of a through-knee amputation level using a free fillet of sole flap.

A young adult male sustained a compound crural fracture with a 15 cm defect of tibia and fibula, and an extensive soft-tissue loss of the lower leg and knee joint. A free fillet of sole flap was raised on the amputated foot and transferred to the soft-tissue defect around the femoral condyles in order to prevent an above-knee amputation. Intact vascularisation and sensation of the flap were secured by microsurgical anastomoses of the popliteal and posterior tibial vessels and the sciatic and tibial nerves. The patient was rehabilitated rapidly with a prosthesis. At the 12-month follow-up, he demonstrated excellent "foot" sensibility, stable soft-tissue coverage of the stump, and an optimal functional result.

[Acute subdural hematoma following minor head injury]. / Acuut subduraal hematoom na licht schedeltrauma.

A 73-year-old patient is described who developed tentorial herniation after a minor head trauma. The initial neurological examination was normal and she had no skull fracture. The cause turned out to be a subdural haematoma of arterial origin, without cerebral contusion or oedema. Prompt surgical intervention resulted in a excellent outcome. The authors conclude that a special form of acute subdural haematoma should be distinguished, which after minor head injury and a lucid interval results in sudden neurological deterioration, especially in the elderly. It has to be treated by prompt surgical intervention.

Ultrastructural changes in the blood-brain barrier of mice infected with Plasmodium berghei.

Mice infected with the rodent malaria parasite Plasmodium berghei exhibit ultrastructural changes of the blood-brain barrier during the course of infection. Firm adherence including cellular interdigitation of infected cells or leucocytes and even clusters of cells to the vascular-endothelial lining is repeatedly observed early during infection. Ghosts and membrane remnants can be found engulfed in the surface of the endothelial cells. Frequently leucocytes migrate between endothelial cells and even cause a lift off and degeneration of these cells. In addition, endothelial cells exhibit increased pinocytotic activity, many irregular cytoplasmic extensions and even phagocytic activity. These changes are associated with degenerative changes in the basement membrane. Swelling and deposition of collagen-like fibres and even loss of fragments of basement membrane is observed. In some places fingerlike extensions of pericytes passed through the basement membrane and contacted or even bulged into the cytoplasm of endothelial cells. Ballooning and even coalescence of perivascular astrocytes was observed and contributed to the appearance of a perivascular oedematous space. The observed changes indicate a progressive deterioration of the blood-brain barrier eventually leading to endothelial lesions and hemorrhage.

Morphological characteristics of intracerebral arterioles in clinical (Plasmodium falciparum) and experimental (Plasmodium berghei) cerebral malaria.

Spastic constriction of intracerebral arterioles was identified in clinical (P. falciparum) and experimental (P. berghei) cerebral malaria. Morphological criteria were used to characterize pathologically spastic constriction of arterioles. The significance of spastic constriction of intracerebral arterioles for microcirculatory disturbance in relation to development of cerebral malaria is discussed.

A cytochemical study of cerebrovascular lesions in mice infected with Plasmodium berghei.

Mice with a Plasmodium berghei infection exhibit morphological and cytochemical changes in the blood-brain barrier. Changes in activity and localization of alkaline phosphatase and adenosine triphosphatase, enzymes with important functions in the maintenance of the blood-brain barrier, were observed. Changes in activity and localization of those enzymes in and near the endothelial cells of the microvasculature, concomitant with an increase in pinocytotic activity, and formation of irregular cytoplasmic extensions in these cells, as well as loosening of the basal lamina are indicative of a functional deterioration of the blood-brain barrier in the course of infection.

Histochemistry of cerebral lesions in mice infected with Plasmodium berghei.

The brains of mice with established symptoms of Plasmodium berghei erebral malaria were investigated histochemically and histologically. The activity of mitochondrial, lysosomal, glyco/glycogenolytic, hydrolytic and oxidizing enzymes as well as enzymes of the Krebs cycle and the pentose cycle was studied during the course of the infection. For comparison cryostate sections were also stained with haematoxylin and eosin, and according to Kluver-Barrera. Changes in enzyme activity, particularly of the vascular endothelium suggest a functional alteration of the blood-brain barrier which precedes the histochemically detectable lesions of the brain parenchyma. Decrease and total loss of enzyme activity in circumscript areas, also of ependymal cells were indicative of an early ischemic lesion. A population of small, non-phagocytozing, granuloma-like cells frequently accumulating in the frontobasal regions and in the subependymal zones were probably immature astrocytes. During early infection, these cells apparently fail to differentiate and turn to necrosis at the end of the second week. The results of this study support the concept of a triggering role of an initial vascular lesion and a functional breakdown of the blood-brain barrier in susceptible areas of the brain, in the pathogenesis of experimental malaria.