Search

Objectives: The aim of this study was to determine whether intravenous immunoglobulin (IVIG) prevents cerebral vasospasm in rabbits with induced subarachnoid haemorrhage (SAH). The effect of IVIG on apoptosis in the endothelial cells of the basilar artery was also evaluated., Methods: Eighteen New Zealand white rabbits were allocated randomly into three groups. SAH was induced by injecting autologous blood into the cisterna magna. Group 1, the control group, was subjected to sham surgery (no induction of SAH). Group 2 had SAH alone and Group 3 had SAH plus IVIG. Three days after treatment, the animals were sacrificed. The basilar artery tissues were analysed histologically and the malondialdehyde levels in the brain stem tissues were evaluated biochemically., Results: Differences in the histopathological luminal areas and full wall thicknesses in the SAH plus IVIG group and the SAH group were statically insignificant (p > 0.005). The malondialdehyde level was also found to be lower in the IVIG group than in the SAH group, although this difference was not significant (p > 0.005)., Conclusion: Although the IVIG treatment was revealed to have no vasodilator effect on the SAH-induced spastic basilar artery, it was shown to have a beneficial effect on the apoptosis of endothelial cells, probably via anti-inflammatory mechanisms.

Background: The aim of this study was to produce an internal carotid artery (ICA) occlusion model in dogs that can be used for studying the effects of surgical revascularization procedures., Material/methods: After left frontoparietal craniectomy, the ICA and arterial circle of the brain were coagulated and transected, letting the middle cerebral artery be perfused by the contralateral ICA by way of the rostral cerebral artery in five mongrel dogs. Magnetic resonance imaging (MRI) and brain single-photon emission computed tomography (SPECT) were performed during the first 24 to 48 hours and 7 to 10 days after the operation. Paired t and Wilcoxon matched pair tests were used for statistics (p<0.05)., Results: All the dogs had postoperative hemiparesis that returned to normal after 7 to 10 days. Early MRI showed cerebral ischemia in the left parietal cortical area extending to the subcortical white matter, sparing the basal ganglion and the internal capsule. Early brain SPECT demonstrated hypoperfusion corresponding to the same area. This area became significantly restricted to a small cortical area in late MRI and SPECT images (p<0.05)., Conclusions: It is concluded that, as symptoms resolved spontaneously, this model can be used as a "reversible ischemic neurological deficit" model for diagnostic imaging and pharmacological studies.

The role of lactate composition of cerebrospinal fluid (CSF) with vasospasm severity and rabbit neurologic status in subarachnoid hemorrhage was determined. The neurologic status of 20 New Zealand rabbits were graded initially and then, anesthetized and basal angiograms were performed. Then 1.0 mL of CSF was withdrawn through cisterna magna and then 1 mL autologous arterial blood was injected in all rabbits over 1 minute. After 5 days, neurologic severity score (NSS) and vertebrobasilar angiograms of all rabbits were repeated. Rabbits without radiologic vasospasm or spasm under 50% (n=7) were termed as group 1. Rabbits whose cerebral vasospasm were 50% or over 50% (n=7) and NSS is lesser than 3 were termed as groups 2, and rabbits whose cerebral vasospasm were 50% or above 50% (n=7) and NSS is greater than 3 were termed groups 3. On day 7, the CSF lactate values of each group were significantly different (P<0.05) with each other. But when compared with only CSF baseline lactate values groups 2 and 3 were significantly different (P<0.05). However, the NSSs were similar in groups 1 and 2, but group 3 significantly differed from groups 1 and 2 (P<0.05). All groups significantly differed from baseline NSSs (P<0.05). The data showed clearly that the degree of vasospasm correlates not only with neurologic status but also with CSF lactate levels. We suggest that CSF lactate level may be useful as a surrogate marker of cerebral vasospasm degree after subarachnoid hemorrhage in clinics where invasive cerebral angiography could not be assessed for whatever reasons.

Purpose: To evaluate the correlation between magnetic resonance imaging (MRI) findings and 99mTc-hexamethylpropyleneamine oxime (HMPAO) brain single photon emission computed tomography (SPECT) during the subacute stage in ischemic stroke patients., Material and Methods: The T1 and T2-weighted images and brain SPECT findings of 84 patients (mean age 60.69 +/- 12.47 years) with subacute cerebral ischemia during the period 1998-2004 were reviewed. All HMPAO SPECT and MRI studies were performed between 3 and 7 days (mean time delay 4.76 +/- 1.29 days) after the onset of stroke symptoms., Results: An ischemic lesion was seen both in T1 and T2-weighted images with perfusion defects above 60% (severe defect) according to count/pixel data of the lesion in HMPAO SPECT studies in 30 (90.9%) of 33 patients. Otherwise, the ischemic lesion was seen only on T2-weighted images with perfusion defects between 30% and 60% (moderate defect) in HMPAO SPECT studies in 25 (89.3%) of 28 patients. In 20 (87%) of 23 patients who had perfusion defects below 30% (mild defect) on HMPAO SPECT, only non-specific findings such as cerebral atrophy and/or periventricular ischemic-gliotic lesions could be seen in MRI. The difference between these ratios was statistically significant (P < 0.01)., Conclusion: Brain 99mTc-HMPAO SPECT findings indicate good correlation with MRI findings. When the ischemic lesions could be seen in both T1 and T2-weighted images, the patients frequently had severe perfusion defects. When only seen in T2-weighted images, the perfusion defect was moderate. When only non-specific findings were revealed by MRI, only mild perfusion defects were found by SPECT.

Objective: In the present study, the effects of magnesium sulfate (MgSO4) on tissue lactate and malondialdehyde (MDA) levels after spinal cord trauma (SCT) in rabbits were studied., Subjects: Thirty New Zeland rabbits. Interventions. The rabbits were divided equally into three groups: group I was the sham- operated group, group II suffered from SCT but received no treatment, group III was given a dose of 100 mg/kg of magnesium sulfate intravenously at 5th minute after SCT. MEASUREMENTS. The lactate and MDA levels were measured in contused spinal cord tissue at 60 minutes after SCT. There was a significant increase of lactate and MDA levels in group II (p < 0.05) when compared with groups I and III, and a significant increase in the level of MDA in group III compared with group I, and also a significant decrease compared with group II, which was the trauma group without treatment (p < 0.05)., Conclusion: The findings of this study showed that magnesium sulfate can attenuate the increase of tissue MDA and supply a normalization of lactate levels following SCT which may be related to the neuroprotective effects of (MgSO4).

The possibility of creating a middle meningeal artery (MMA)-to-petrous internal carotid artery (ICA) bypass was investigated in six cadavers (bilaterally). Such a procedure could be used to treat patients with high cervical vascular lesions and those with tumors of the infratemporal fossa invading the high cervical ICA. After a frontotemporal craniotomy, the foramen spinosum and foramen ovale were exposed extradurally. Immediately posterior to the foramen ovale and medial to the foramen spinosum, the petrous portion of the ICA was exposed with a diamond-tipped drill. The MMA was lifted from its groove, and a sufficient length was transected to perform a bypass with the petrous ICA medially. The mean width of the MMA at the site of anastomosis was 2.3 +/- 0.35 mm. The mean length of MMA from the foramen spinosum to the site of the anastomosis was 9.6 +/- 1.7 mm. Based on these measurements, width and length of MMA appear to be sufficient for a bypass with petrous ICA.

Background: The aim of our study was to identify congenital morphological abnormalities of distal vertebral arteries (CMADVA) and their association with cerebral hypoperfusion leading to vertigo, and the role of MR and MRA in the diagnosis of vertebrobasilar (VB) abnormalities., Material/methods: 768 patients who complained of dizziness and/or vertigo were included in the study and evaluated by MR and MRA. CMADVAs were determined in 88 of the cases with no other explanation for vertigo and dizziness. 150 patients without dizziness or vertigo were used as a control group. The 3D TOF (Time- of- flight) MR angiographic technique was used., Results: CMADVAs were detected in 88 of 768 patients (11.5%) with vertigo and/or dizziness. We also detected CMADVAs in 4 (2.7%) of 150 persons in the control group. The patients with abnormal vertebral artery findings were classified into ten categories. Lacunar infarcts in the brain stem were found in 8 patients after long-duration vertigo attacks. There was significant correlation between the control and vertigo groups in terms of CMADVA (p=0.0001). After excluding the control group, there was a significant relationship between CMADVA and vertigo and/or dizziness symptoms (p=0.0001)., Conclusions: We believe that vertigo and dizziness associated with CMADVA is a real entity that deserves greater attention. For this reason, the vertebrobasilar system in these patients should be examined for CMADVA with MRA. This would enable us to take preventive measures against brainstem ischemia or at least elucidate the etiology of vertigo in these patients.

We present the use of radial artery graft for bypass of the proximal superficial temporal artery to the proximal middle cerebral artery. Six adult cadaver sites were used bilaterally. After apterional incision, 2x2-cm minicraniectomy was performed which began 2 cm behind the zygomatic process of the frontal bone. The superficial temporal artery was transsected before exposing the zygomatico-orbital artery branch. The proximal side of the radial artery graft was anastomosed end-to-end to the proximal superficial temporal artery and the distal side end-to-side to the proximal middle cerebral artery. The mean calibers of the proximal superficial temporal artery and largest trunk of the middle cerebral artery were 2.25+/-0.35 mm and 2.3+/-0.3 mm, respectively. The average graft length was 85+/-5.5 mm. We conclude that such bypasses are simpler than proximal middle cerebral artery revascularization using long vein grafts. This method proves that the caliber of the proximal superficial temporal artery is more suited to providing sufficient flow than the distal superficial temporal artery, and the graft is short. Such bypasses to the middle cerebral artery may be an alternative to those from the distal superficial temporal artery or extracranial carotid artery.

Background: A failure of the Na(+),K(+)-ATPase activity (which is essential for ion flux across the cell membranes) occurs in many pathological conditions and may lead to cell dysfunction or even cell death. By altering the concentration of specific opioid peptides, gamma-hydroxybutyric acid (GHB) may change ion flux across cell membranes and produce the 'channel arrest' which we assumed will inhibit the failure of Na+,K(+)-ATPase activity and therefore lead to energy conservation and cell protection. Therefore we planned this study to see the effects of GHB at two different doses on Na(+),K(+)-ATPase activity in an experimental head trauma model., Methods: Forty New Zealand rabbits were divided equally into four groups: group I was the sham-operated group, group II (untreated group), group III received head trauma and intravenous (i.v.) 500 mg/kg GHB and group IV received head trauma and i.v. 50 mg/kg GHB. Head trauma was delivered by performing a craniectomy over the right hemisphere and dropping a weight of 10 g from a height of 80 cm. The non-traumatized (left) side was named as 'a' and the traumatized (right) side as 'b'. One hour after the trauma in groups II and III and craniotomy in group I, brain cortices were resected from both sides and in group I only from the right side was the tissue Na-K-ATPase activity determined., Results: The mean +/- SD of Na(+),K(+)-ATPase levels of each group are as follows: group I - 5.97 +/- 0.55; group IIa - 3.90 +/- 1.08; group IIb - 3.58 +/- 0.90; group IIIa - 5.53 +/- 0.60; group IIIb - 5.33 +/- 0.88; group IVa - 5.05 +/- 0.72; group IVb - 4.93 +/- 0.67. The Na(+),K(+)-ATPase levels of group IIa, IIb, IVa and IVb were significantly different from group S (P < 0.05). There were also significant differences between group IIa and groups IIIa and IVa; group IIb and groups IIIb and IVb (P < 0.05)., Conclusions: We conclude that GHB is effective in suppressing the decrease in Na(+),K(+)-ATPase levels in brain tissue at two different dose schedules after head trauma.

Background: This study was designed to determine the effects of gamma-hydroxybutyric acid (GHB) on tissue lactate and malondialdehyde (MDA) levels in rabbit brain after experimental head trauma., Methods: Thirty New Zealand rabbits were divided equally into three groups: group S was the sham-operated group, group C, and group GHB received head trauma, where group C was the untreated and group GHB was the treated group. Head trauma was delivered by performing a craniectomy over the right hemisphere and dropping a weight of 10 g from a height of 80 cm. GHB was administered 400 mg/kg intravenously for 10 minutes after the head trauma to group GHB. The nontraumatized side was named "1" and the traumatized side was named "2." One hour after trauma, brain cortices were resected from both sides and the concentrations of lactate and MDA were determined., Results: There were significant differences between lactate and MDA levels of group S and all other groups (C1, C2, GHB1, and GHB2) except between lactate levels of group S and group GHB1, the nontraumatized and traumatized sides of groups C and group GHB, group C2 versus group GHB2, and group C1 versus group GHB1 (p < 0.05). Rectal temperature after the administration of GHB in group GHB was found lower than in groups S and C (p < 0.05)., Conclusion: These results demonstrate that head trauma leads to an increase in brain tissue lactate and MDA levels, and GHB effectively suppresses the increase of lactate and MDA.

Objective: In this study, we aimed to investigate the use of a radial artery graft for bypass of the maxillary artery (MA) to the proximal middle cerebral artery (MCA) as an alternative to superficial temporal artery-to-MCA anastomosis or extracranial carotid-to-MCA bypass using long grafts., Methods: Five adult cadavers were used bilaterally. After a frontotemporal craniotomy and a zygomatic arch osteotomy, the MA was found easily 1 to 2 cm inferior to the infratemporal crest. A hole was created with a 4-mm-tip drill in the sphenoid bone 2 to 3 mm lateral to the foramen rotundum extradurally, and the dura over the hole was opened. After the carotid and sylvian cisterns had been opened, the M2 segment of the MCA was exposed. The graft was passed through the hole to reach the M2 segment. Then, the MA was freed from the surrounding tissue and was transected before the infraorbital artery branch. The radial artery graft was anastomosed end-to-end to the MA proximally and end-to-side to the M2 segment of the MCA distally., Results: The mean thickness of the MA before the infraorbital artery branch was 2.6 +/- 0.3 mm. The mean thickness of the largest trunk of the MCA was 2.3 +/- 0.3 mm. The average length of the graft was 36 +/- 5.5 mm., Conclusion: MA-to-MCA bypass is as feasible as proximal MCA revascularization using long vein grafts. The thickness of the MA provides sufficient flow; the length of the graft is short, and it has a straight course. MA-to-proximal MCA bypass may be an alternative to superficial temporal artery-to-MCA as well as extracranial carotid-to-MCA bypasses.

Objective: To determine the role of hyperoxic and hyperbaric therapy following experimental subarachnoid hemorrhage (SAH)., Design: Prospective, randomized, controlled animal study., Subjects: Thirty male Wistar rats., Interventions: Thirty rats were assessed for an initial neurologic status as double-blinded by two different neurosurgeons using a neurologic severity score (NSS) and then underwent an initial angiographic examination. Two days later, 0.3 ml of homologous blood was injected into the cisterna magna to produce a SAH-induced cerebral vasospasm. The NSS and angiographic examination were then repeated. The rats having no spasm or a spasm under 50% (n=8) and 50% or over 50% (n=22) were grouped separately, as groups 1 and 2, respectively. The rats having 50% or more spasm were further divided randomly into group 2A and 2B. The rats in groups 1 and 2A (n=11) underwent a 60-min course of 100% oxygen at the atmospheric pressure 1 atmosphere absolute (ata), and group 2B (n=11) received 100% oxygen at 3 ata for 1 h. Neurologic assessment was repeated on the next day and 7 days later., Measurements and Main Results: The animals having no spasm or less than 50% spasm had a better NSS and outcome when compared with the animals having 50% or more spasm. But the animals with 50% or more spasm which underwent hyperbaric therapy were shown to have a better outcome compared to the animals having hyperoxic therapy., Conclusion: Exposure to hyperbaric oxygen therapy seemed to accelerate the recovery of neurologic deficits secondary to experimental SAH.

The possibility for maxillary artery (MA) to petrous internal carotid artery (ICA) bypass was investigated. Five adult cadavers were dissected bilaterally. After zygomatic arch osteotomy, the coronoid process was sectioned at its base. An extensive infratemporal craniotomy was performed at the level of foramina ovale, rotundum and spinosum. The petrous portion of the ICA was exposed by drilling away the floor of the middle fossa, posterior to the foramen ovale and medial to the foramen spinosum. The MA was identified medial to the infratemporal crest and was followed in the pterygopalatine fossa, then transected at the origin of the infraorbital artery. The MA graft was brought posteromedially to reach the petrous ICA. The mean caliber of the MA before the origin of the infraorbital artery was 2.54+/-0.31 mm, 2.76+/-0.14 mm at the site of anastomosis, and 3.46+/-0.32 mm after giving off the middle meningeal artery. The average length of the MA between the middle meningeal artery and the infraorbital artery was 43.4+/-2.35 mm, and up to the site of anastomosis was 37.64+/-1.68 mm. We conclude that the length and diameter of the MA are sufficient for a tension-free anastomosis between MA and petrous ICA, and such a procedure could be used in the treatment of patients with tumors of the infratemporal fossa invading the high cervical ICA.

Purpose: The aim of this study was to determine whether omental transposition at the time of focal cerebral ischemia can decrease ischemic brain damage produced in dogs, in a new ischemia model, which had been described by us., Methods: In group 1 (n = 5), the left internal carotid artery and arterial circle of the brain (posterior communicating artery in humans) were occluded permanently. In group 2 (n = 5), additionally to this ischemia model, omental transposition was performed simultaneously. In the postoperative early period (first 24 h), single photon emission computed tomography (SPECT) and in the late period (72-96 h) SPECT and magnetic resonance imaging (MRI) of the brain were performed. Mann-Whitney U, paired t and Wilcoxon signed rank tests were used for statistical analyses, and p < 0.05 was considered significant., Results: The dogs had a neurological score (NS) of 3.6 +/- 0.5 and 3.4 +/-0.5 in groups 1 and 2, respectively, in the early period (p > 0.05). In the late period, the dogs had an NS of 4.4 +/- 0.5 and 5.6 +/- 0.5 in groups 1 and 2, respectively (p < 0.05). The NS of each group differed significantly between the early and late period (p < 0.05). Early SPECT imaging showed 50 +/- 7.0% and 52 +/- 8.4% hypoperfusion corresponding to the left middle cerebral artery territory in groups 1 and 2, respectively (p > 0.05). In the late period, the degree of hypoperfusion decreased to 34 +/- 5.5% and 12 +/- 4.8% in groups 1 and 2, respectively (p < 0.05). The degree of hypoperfusion in both groups changed significantly between the early and late period (p < 0.05). In T(1)- and T(2)-weighted MRI images, the volume of the lesion in group 1 was significantly greater than in group 2 (p < 0.001)., Conclusion: In our new ischemia model, simultaneous omental transposition is helpful in reversing the neurologic deficit and cerebral ischemic damage., (Copyright 2003 S. Karger AG, Basel)

After a few reports on end-to-side nerve repair at the beginning of the last century, the technique was put aside until its recent reintroduction. The authors present their results in three patients with median nerve defects that were between 15 and 22 cm long and treated using end-to-side median-to-ulnar neurorrhaphy through an epineurial window. The follow-up times were between 32 and 38 months. Sensory evaluation involved superficial touch, pinprick, and two-point discrimination tests. Motor evaluation was completed by assessing the presence of opposition and by palpating the abductor pollicis brevis muscle. Sensory recovery was observed in all patients in the median nerve dermatome, and motor recovery was absent, except in Case 1. End-to-side nerve repair can be a viable alternative to nerve grafting in patients with long gaps between the ends of the injured nerve.

Objective: The objective of this study was to develop an electroencephalographic grading scale for evaluating the severity of head trauma and assessing the correlation of this scale with brain tissue lactate concentrations., Design: Animal experiment., Setting: Animal research laboratory in a university hospital., Subjects: Thirty New Zealand rabbits were divided into three groups., Interventions: Rabbits were anesthetized, and bilateral frontoparietal craniectomy was performed. An electroencephalogram was recorded over the dura from both sides. After electroencephalographic recording, unilateral trauma was produced by using the weight drop method with a calculated force of 400 g.cm and 800 g.cm in group 2 (n = 10) and group 3 (n = 10), whereas in group 1 (n = 10) only craniectomy was performed. Electroencephalographic recording was repeated 60 mins after trauma or craniectomy, and cortical tissue samples were resected from both sides to evaluate tissue lactate concentrations in all three groups., Measurements and Main Results: Electroencephalographic recordings from both sides of the brain were evaluated together by using a 6-point scale (1 = best to 6 = worst) that was based on the presence or absence of electroencephalographic activity and the decrease in amplitude or frequency band of the electroencephalogram. Lactate was measured in resected tissue by using spectrophotometric enzymatic methods. One-way analysis of variance for repeated measures, Bonferroni-adjusted paired Student's -test, Kruskal Wallis analysis of variance, Bonferroni-adjusted Mann-Whitney-U, and Spearman's correlation tests were used as appropriate for statistical analysis. We considered p<.05 to be significant. The difference in lactate concentrations was significant between the three groups ( p<.05). Electroencephalographic grades were significantly different between the pretraumatic and posttraumatic recordings ( p<.05) and between the three groups after craniectomy or trauma ( p<.001). There was a positive high correlation between lactate concentrations and electroencephalographic grades., Conclusions: Tissue lactate concentrations and electroencephalograhic grades change with the severity of the trauma, and there is a strong positive correlation between tissue lactate concentrations and electroencephalographic grades.

We studied the effects of nimodipine on brain tissue lactate and malondialdehyde (MDA) levels one hour after experimental head trauma in 25 New Zealand rabbits. Group 1 (n=5) was the sham operated group. Group 2 (n=10) received head trauma without treatment and in group 3 (n=10) nimodipine was administered for 30 minutes intravenously (2 microg/kg/min) immediately after head trauma. In groups 2 and 3, tissue samples from the non-traumatized side was named as "a" and traumatized side as "b". The lactate and malondialdehyde contents were significantly higher in groups 2a, 2b, 3a and 3b when compared with to group 1 (P<0.05). The differences between non-treated groups (2a, 2b) and nimodipine treated groups (3a, 3b) were not significant (P>0.05). The differences between the traumatized sides (2b, 3b) and non-traumatized sides (2a, 3a) were significant (P<0.05). These results demonstrated that nimodipine is ineffective in suppressing the increase of tissue lactate and malondialdehyde levels in the early period of experimental head trauma.

Six patients received 1 g and six other patients received 2 g of cefoperazone and sulbactam 15 minutes before lumbar disc surgery. Liquid chromatographic analysis of disc tissue revealed that only patients receiving the 2-g dose had mean tissue levels above the minimum inhibitory concentration for Staphylococcus aureus and epidermidis.

Background: The aim of this study was to investigate whether enhanced stimulation voltage could be a predictor of the extent of injury in acute compressive peripheral nerve trauma., Methods: The femoral nerves were exposed on both sides, in 11 anesthetized rabbits. Supramaximal stimulation voltage was used to produce a maximal-amplitude compound muscle action potential (CMAP) from the quadriceps femoris muscle. Afterward, the left femoral nerve was clipped for 1 minute, and the right femoral nerve for 5 minutes to produce an acute compressive injury. Immediately after removal of the clip, the proximal and distal sides of the clippage site were stimulated by gradually increased voltage until CMAPs were obtained. The same procedure was repeated at the 30th and 60th minutes. The ratio of the CMAP amplitudes obtained from proximal and distal stimulation was measured to establish a classification., Results: The stimulation voltages and amplitudes of the CMAPs before clippage were similar with the after-clippage values obtained from distal stimulation (p > 0.05), but the after-clippage values obtained from proximal stimulation were different in both sides (p < 0.05). Doubled stimulation voltage was enough to obtain CMAPs on the left side, but eightfold the initial level was required on the right side. The amplitude ratios recovered to preinjury levels in all of the subjects on the left side, but only two showed recovery on the right side (p < 0.001). Histopathologically, there was axonal compression without discontinuity on the left side, whereas the fibers were dispersed on the right side., Conclusion: Stimulation voltage was found to discriminate the severity of the lesion in experimental peripheral nerve injury. Proximal to distal amplitude ratio seems to be a prognostic factor when the injury is less severe.

The use of a saphenous vein graft for bypass of the maxillary artery (MA) to the supraclinoid internal carotid artery (ICA) in internal carotid occlusions is investigated. Five adult cadaver sides were used. Dissection required zygomatic arch osteotomy and a pterional craniotomy with extensive removal of the floor of the middle cranial fossa. The MA was found easily medial to infratemporal crest. The clinoidal segment of the ICA was exposed with the removal of the anterior clinoid process intradurally. The bypass graft was 4 to 5 cm long and was sutured end-to-end to the MA and end-to-side to the supraclinoid ICA. When high blood flow is needed in cases with ICA occlusion, such a bypass may be an alternative to superficial temporal (STA)-to-middle cerebral artery (MCA) bypass as well as to common carotid-to-MCA or-ICA bypass, which needs a long vein graft. This type of bypass will provide the opportunity to clip the ICA proximal to the origin of ophthalmic artery, which may inhibit distal embolization.

To examine the effects of calcium antagonists nimodipine and magnesium sulfate (MgSO4) on tissue endogenous antioxidant levels, the authors studied superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels in rabbit brain 1 hour after experimental head trauma. Forty New Zealand rabbits were anesthetized and randomly divided into four groups. Group 1 (n = 10) was the sham operated group. Group 2 (n = 10), the control group, received head trauma and no treatment. Group 3 (n = 10) received head trauma and intravenous (IV) 2 microgr/kg nimodipine. Group 4 (n = 10) received head trauma and IV 100 mg/kg MgSO4. Head trauma was delivered by performing a craniectomy over the right hemisphere and dropping a weight of 20 g from a height of 40 cm. In the right (traumatized) hemisphere, SOD and GPx decreased by 57.60% +/- 9.60% and 72.93% +/- 5.51% respectively from sham values. Magnesium sulfate, but not nimodipine, reduced the magnitude of decrease of SOD and GPx to 19.43% +/- 7.15% and 39.01% +/- 7.92% respectively from sham values. In the left (nontraumatized) hemisphere, MgSO4 increased SOD to 42.43% +/- 24.76% above sham values. The authors conclude that MgSO4 treatment inhibited the decrease in SOD and GPx levels in experimental brain injury.

Object: In cases of irreparable injuries to the radial nerve or in cases in which nerves are repaired with little anticipation of restoration of function, tendon transfers are widely used. In this study, the authors searched for a more natural alternative for selectively restoring function, with the aid of a motor nerve transfer., Methods: Ten arms from five cadavers were used in the study. The posterior interosseous nerve and the median nerve together with their motor branches were exposed in the proximal forearm. The possibility of posterior interosseous nerve neurotization via the median nerve through its motor branches leading to the pronator teres, flexor pollicis longus, flexor digitorum profundus, and pronator quadratus muscles was investigated. The lengths of the nerves from points of divergence and their widths were measured using calipers, and the means with standard deviations of all nerves were calculated. Motor branches to the pronator teres, flexor pollicis longus, and pronator quadratus muscles were found to be suitable for neurotization of the posterior interosseous nerve at different levels and in various combinations. The motor nerve extending to the flexor digitorum profundus muscle was too short to use for transfer., Conclusions: These results offer a suitable alternative to tendon transfer for restoring finger and wrist extension in cases of irreversible radial palsy. The second step would be clinical verification in appropriate cases.

Opposition, one of the most important functions of the hand, is lost or impaired after median nerve injury. Complete recovery does not always occur after treatment, and various techniques of opponensplasty are used for restoring opposition. This study was performed in order to develop an alternative method for selective restoration of thenar muscle function. Ten arms from 5 cadavers were used. The median nerve with its thenar motor branch (Tb) and the anterior interosseous nerve with its motor branch to pronator quadratus (PQb) were prepared in the distal forearm. The mean widths and the number of myelinated fibres of these nerves were: PQb 1.3+/-0.10 mm, Tb 1.4+/-0.12 mm and PQb 912+/-88 mm, Tb 1020+/-93 mm. The minimum necessary distance from the distal flexor crease of the wrist for neurotisation of the Tb by the PQb was 60+/-5.41 mm. It was concluded that PQb-Tb neurotisation would be possible anatomically. The advantages are that motor function is reestablished with a motor nerve, the diameters and the number of myelinated fibres of both nerves are similar, the loss of function after denervation of the pronator quadratus is slight and opponensplasty still remains as a final option.

Background: Proximal ulnar-nerve lesions have an unfavorable prognosis. The goal of the present study was to evaluate the feasibility of selective restoration of motor function of the ulnar nerve by the transfer of the anterior interosseous nerve or one of its branches to the motor branch of the ulnar nerve., Methods: Ten cadaveric arms were used in the present study. The ulnar nerve and its motor and sensory branches as well as the anterior interosseous nerve and its branches were dissected. The widths of the motor branch of the ulnar nerve and the anterior interosseous nerve and its motor branches as well as the relevant distances from the points of divergence were measured. The axons were counted, and the distances from the end of the main anterior interosseous nerve, its motor branches, and the motor branch of the ulnar nerve to the level of the dorsal sensory branch of the ulnar nerve were measured., Results: Our results indicate that the length, width, and number of axons of the branch of the anterior interosseous nerve to the pronator quadratus make it suitable for transfer to the motor branch of the ulnar nerve. The use of the main anterior interosseous nerve or its motor branches to the flexor pollicis longus and the flexor digitorum profundus is less feasible because of the need to graft a long segment and the longer distance from the level of transfer to the motor end points., Conclusions: The findings of the present study confirm the feasibility of motor-nerve transfer for reconstruction after an injury of the ulnar nerve. Nerve-grafting would be needed for injuries distal to the level of the dorsal sensory branch of the ulnar nerve.

Objective: To determine the effects of magnesium sulfate (MgSO4) on tissue lactate and malondialdehyde (MDA) levels in rabbit brain after experimental head trauma., Design: Prospective, randomized trial., Subjects: Thirty New Zealand rabbits., Interventions: Group 1 (n = 10) was the sham operated group. Group 2 (n = 10) (untreated group) and group 3 (n = 10) received head trauma with the weight drop method. MgSO4 was administered 100 mg/kg (15 %) i. v. immediately after the head trauma to group 3. Trauma was applied to one side. The non-contused side was named as "a" and the contused side as "b"., Measurements: One hour after trauma, brain cortices were resected and the concentrations of lactate and MDA were determined using the spectrophotometric enzymatic and thiobarbituric acid methods. One-way ANOVA and Tukey's HSD tests were used for the evaluation of the results. P < 0.05 was considered as significant. Pearson's correlation test was used between lactate and MDA levels (P < 0.001)., Results: There were significant differences between MDA and lactate levels of group 1 and all other groups; non-contused (a) and contused (b) sides of groups 2 and 3; groups 2b-3a, 2b-3b (P < 0.05). The difference in MDA levels was significant between groups 2a-3b (P < 0.05). Correlation between lactate and MDA was very good in group 1, and excellent in groups 2a, 2b, 3a, and 3b., Conclusions: These results demonstrate that head trauma leads to an increase in brain tissue lactate and MDA levels, and MgSO4 suppresses the rise in contused tissue when given after head trauma.

Neurotisation involves transfer of nerves for the restoration of function following injury. A number of nerves have been used in different part of the peripheral nervous system. This study was undertaken to develop a practical and relatively safe surgical approach to the treatment of L4 root lesion's. We examined the effectiveness and safety of neurotisation of the deep peroneal nerve and its branches by the superficial peroneal nerve. Twelve legs of dissected cadavers provided for teaching purposes in the anatomy laboratory were used to display the common peroneal nerve and its branches. Each branch was measured using calipers and analysed to investigate the possibility of neurotisation of the deep peroneal nerve by the superficial peroneal nerve and its branches. It was found that of the measured branches, transposition was possible between those to peroneus longus and tibialis anterior on the basis of their diameter and length. In recent decades, advances in microsurgical reconstruction and understanding of the microanatomy have played major roles in improving the results of surgical treatment of nerve injuries. There is a need for further experimental studies on the feasibility of this surgical approach.

We studied the effects of high-dose dexamethasone on amplitude and latency values of spinal cord evoked potentials. Thirty-three rabbits were divided into three equal groups. The first group served as the control group, the others received high-dose (2.5 mg/kg) dexamenthasone, the second group 1 hour prior to and the third group immediately after the induction of a spinal cord trauma in segment T12. The spinal cord evoked potentials were recorded epidurally from T12 segment 5 min before and 5, 30, 60, 90, 120 and 150 min after trauma. Pretreatment with dexamethasone (group II) prevented the latency delay, and later treatment with dexemethasone (group III) prevented the latency delay partially. Our results suggest that when dexamethasone is given prophylactically it prevents latency alteration, while treatment with dexamethasone after lesioning prevents latency alteration partially. From our results we conclude that pretreatment with dexamethasone may involve different mechanisms than were activated in the posttreatment group.