No abstract

The incidence, magnitude, and duration of acute pain experienced by neurosurgical patients after various brain operations are not precisely known, because of a lack of well-designed clinical and epidemiological studies. We assessed these important pain variables in 37 consecutive patients who underwent various brain neurosurgical procedures. Postoperative pain was more common than generally assumed (60%). In two-thirds of the patients with postoperative pain, the intensity was moderate to severe. Pain most frequently occurred within the first 48 hours after surgery, but a significant number of patients endured pain for longer periods. Pain was predominantly superficial (86%), suggesting somatic rather than visceral origin and possibly involving pericranial muscles and soft tissues. Subtemporal and suboccipital surgical routes yielded the highest incidence of postoperative pain. Age and sex were significantly associated with the onset of pain, with female and younger patients reporting higher percentages of postoperative pain. Psychological Minnesota Multiphasic Personality Inventory profiles of patients with and without pain significantly differed on the Hypochondriasis scale, with patients without pain scoring unexpectedly higher than patients with pain. It is possible that hypochondriasis serves as a defense mechanism against pain, at least in some patients. Results of this pilot study indicate that postoperative pain after brain surgery is an important, although neglected, clinical problem, that deserves greater attention by surgical teams, to provide better and more appropriate treatment.

The regeneration in the peripheral nervous system is often incomplete and the treatment of severe lesions with nerve tissue loss is primarily aimed at recreating nerve continuity. Guide tubes of various types, filled with Schwann cells, stem cells, or nerve growth factors are attractive as an alternative therapy to nerve grafts. In this study, we evaluated whether skin-derived stem cells (SDSCs) can improve peripheral nerve regeneration after transplantation into nerve guides. We compared peripheral nerve regeneration in adult rats with sciatic nerve gaps of 16 mm after autologous transplantation of GFP-labeled SDSCs into two different types of guides: a synthetic guide, obtained by dip coating with a L-lactide and trimethylene carbonate (PLA-TMC) copolymer and a collagen-based guide. The sciatic function index and the recovery rates of the compound muscle action potential were significantly higher in the animals that received SDSCs transplantation, in particular, into the collagen guide, compared to the control guides filled only with PBS. For these guides the morphological and immunohistochemical analysis demonstrated an increased number of myelinated axons expressing S100 and Neurofilament 70, suggesting the presence of regenerating nerve fibers along the gap. GFP positive cells were found around regenerating nerve fibers and few of them were positive for the expression of glial markers as S-100 and glial fibrillary acidic protein. RT-PCR analysis confirmed the expression of S100 and myelin basic protein in the animals treated with the collagen guide filled with SDSCs. These data support the hypothesis that SDSCs could represent a tool for future cell therapy applications in peripheral nerve regeneration.

No abstract

N-acetylaspartate (NAA) has previously been proposed as a neuronal marker. 1H magnetic resonance spectroscopy (MRS) is able to detect NAA in brain, and decreases of NAA have been documented after brain injury. The reason for this decrease is not fully understood and neuron loss damage and "dysfunction" have all been proposed. It is hypothesized that acute central nervous system (CNS) deafferentation causes a trans-synaptic NAA decrease and that high resolution 1H MRS is able to detect such a decrease. To test this hypothesis, an experimental model was used in which axonal lesions were obtained by stretch injury in guinea pig right optic nerve (95-99% crossed fibers). The trans-synaptic concentration of NAA, total creatine (Cr), and the NAA/Cr ratio in lateral geniculate bodies (LGB) and superior colliculi (SC) sample extracts were measured 72 h later by high resolution 1H MRS. In the left LGB/SC, which is where right optic nerve fibers project, reductions of NAA and NAA/Cr were found whereas Cr levels were normal. NAA, NAA/Cr, and Cr values were all normal in the right LGB/SC. Histology and EM findings revealed no abnormalities. At 7 days, left LGB/SC NAA and NAA/Cr values were in the normal range. It was concluded that 1) acute deafferentation in the CNS causes a trans-synaptic decrease of NAA levels that can be detected by 1H MRS and 2) NAA decrease may be due to changes of NAA metabolism caused by functional neuronal inactivity rather than neuronal loss, injury or "dysfunction." 1H MRS is a potential tool for the study of functional effect of CNS lesions in vivo.

A high success rate in treatment of iNPH is possible in patients with and without CVD. Despite poorer short- and long-term treatment outcome of iNPH patients with CVD, a long-lasting improvement in their quality of life favors surgery.

Objective-To assess the clinical feasibility and the accuracy of two pragmatic methods in comparison with a conventional computer based method of measurement of masses from CT. Methods-Nineteen CT scans of 11 patients with severe head injury, showing 34 traumatic lesions, were examined. The volume of every lesion was digitally measured, then a panel of three examiners independently repeated the measurement using the ellipsoid and the Cavalieri method in random order. Results-All the lesions were identified by all the readers and the mean volume measured by each examiner diVered by less than 1.5 ml. The average reading time for each scan was 4 minutes for the ellipsoid and 7 minutes for the Cavalieri method. The average volume of the lesions was 34.2 (SD 35) ml with the digital system, and 38.4 (SD 41) ml and 34.8 (SD 36) ml for the ellipsoid and the Cavalieri readings respectively. The average diVerence between the applied technique and the digital system was 0.57 (SD 9.99) ml for the Cavalieri direct estimator and 0.20 (SD 15.48) ml for the ellipsoid method. The 95% confidence interval for this diVerence fell between -2.75 and 3.89 ml for the Cavalieri, and between -4.94 and 5.35 ml for the ellipsoid method. There were 19 lesions >25 ml; the ellipsoid method identified 16 of them, whereas 17 were classified with the Cavalieri method. When considering individual lesions rather than the average volume, discrepancies were detected with both methods. The ellipsoid method was less precise, especially when extracerebral lesions were measured. Conclusions-Both pragmatic methods are inferior to computer based reading, which is the choice when accurate volume estimation is necessary. However, if a digital volumetric determination of the lesions using a CT computer is not possible, the two pragmatic methods oVer an alternative.

A new model of focal axonal injury was reproduced by rapid and controlled elongation (uniaxial stretch) of the guinea pig optic nerve. Light microscopy study of optic nerve specimens after horseradish peroxidase injection into the vitreous of the animal's eye showed that axonal lesions were identical to those seen in human and primate post-traumatic diffuse axonal injury (DAI). The lesions were characterized by the formation of terminal clubs in severed axons and focal axonal enlargements in those axons that were lesioned-in-continuity. Visual-evoked potentials upon flash stimulation were recorded before and after injury. Mean amplitude and mean latency of occipital peaks were significantly elongated in the acute post-traumatic phase. Electron microscopy examination showed that the main axonal changes observed in this model were cytoskeleton disorganization, accumulation of axoplasm membrane-bound bodies at the site of terminal balls and dilatations-in-continuity and detachment of the axolemma from the myelin sheath. Such axonal alterations were similar to those found in many other biological models of central and peripheral axonal injuries in which the lesion was produced by invasive methods. This model is unique since it reproduces the same mechanism of injury and the identical lesions that have been demonstrated in humans and primates with post-traumatic (DAI).