Effect of topical rifamycin application on epidural fibrosis in rats.

OBJECTIVES: This study aims to investigate the effects of topical rifamycin SV application on epidural fibrosis formation in a rat model. MATERIALS AND METHODS: Between March 2015 and April 2015, a total of 20 Wistar rats were equally and randomly divided into laminectomy only group (control group) and laminectomy and rifamycin SV group (treatment group). Laminectomy was performed between L3-L5 in all rats. Surgical field was irrigated with 1 mL rifamycin SV (1 mL). After four weeks, vertebral columns of the rats were removed en bloc between the L1 and L5 levels, and epidural fibrosis and arachnoid involvement were histopathologically evaluated and graded. RESULTS: Grade 3 epidural fibrosis formation ratio was lower in the treatment group (40%) compared to the control group (80%). However, there was no statistically significant difference between the treatment and control groups in terms of epidural fibrosis (p=0.164) and arachnoid involvement (p=0.303). CONCLUSION: Intraoperative rifamycin irrigation tends to reduce epidural fibrosis formation risk, although not statistically significant.

Morphometric Analysis of Dose-dependent Effect of Progesterone on Experimental Vasospasm-induced Rat Femoral Arteries.

OBJECTIVE: Our aim of this study was to determine effective doses of progesterone which has a vasodilatory effect during the early stage of vasospasm. Cerebral vasospasm (CV) is a predominant cause of morbidity and mortality which develops following subarachnoidal hemorrhage (SAH). Etiopathogenesis of CV is multifactorial. Despite many previously performed studies on this issue, the mechanism by which blood and blood products in the subarachnoidal space induce CV has not been clarified yet. MATERIALS AND METHODS: In our study, we used "Rat Femoral Artery Vasospasm Model" introduced by Okada et al. Thanks to easy procurement and maintenance of rats. Rats were divided into four groups as: Group 1 (n = 8; control group), Group 2 (n = 8; vasospasm group), Group 3 (n = 8; vasospasm + 3 mg/kg progesterone group), and Group 4 (n = 8; vasospasm +15 mg/kg progesterone group). Progesterone which is an endogenously synthesized natural steroid was preferred in our study. Progesterone increases the production of vasodilatory epoxyeicosatrienoic acid by acting on its binding sites termed as pregnane X receptor. It decreases the intracellular influx of Ca2+ by blocking the functioning of L-type channels in smooth muscle cells. It manifests another vasodilatory effect by decreasing expression of TxA2 receptor. In our study, at the end of the 7th day, where the most intense vasospasm is seen, 1 cm pieces were excised from the femoral arteries and histopathologically examined under light microscope. RESULTS: Vascular walls of three vasospasm-induced groups were relatively thicker when compared with the control group. Drug-treated groups were not different from each other. Vascular walls of the groups treated with lower and higher doses of the drug were thinner when compared with the vasospasm group without any statistically significant difference between groups (P > 0.05). Luminal cross-sectional areas of the drug-treated groups did not differ from each other. Mean luminal cross-sectional areas of the control and the drug-treated groups were larger than that of the vasospasm group without any statistically significant intergroup difference (P > 0.05). CONCLUSION: Based on the results of our study, progesterone did not exert protective effects on vascular wall thickness, while histopathological examination of luminal cross-sectional areas revealed its vasodilatory effects without any statistically significant difference between groups. Starting from the study results obtained, we think that its potential use as a preventive agent against the development of post-SAH CV requires conduction of multicentered, placebo-controlled, randomized, and double-blind studies.

En Plaque Pituitary Adenoma within a Rathke's Cleft Cyst: Report of Three Cases.

Concomitant pituitary adenomas and Rathke's cleft cysts (RCCs) are rare. These coexisting lesions are difficult to diagnose preoperatively due to their variable signal intensity on magnetic resonance imaging (MRI) and position of the RCC. We describe three cases of coexisting pituitary adenoma and RCC, and review the relevant literature. In our cases, the RCCs were relatively large and the en plaque adenomas appeared as enhanced cyst walls on MRI examination. We also report the clinical, radiologic, surgical, and histopathologic findings of each case.

The Axon Protective Effects of Syringic Acid on Ischemia/Reperfusion Injury in a Rat Sciatic Nerve Model.

AIM: In the relevant literature, there is no experimental study that investigated the axon protective effects of syringic acid- a polyphenol compound- with an anti-oxidant capacity on ischemia/reperfusion injury. MATERIAL AND METHODS: The rats were randomly divided into four groups: Control group (no medication or surgical procedure), Sham group, Syringic acid group, and Methyprednisolone (MP) Group. Ischemia was achieved by abdominal aorta clamping and all animals were sacrificed 24 hours after ischemia. Harvested sciatic nerve segments were investigated histopathologically and for tissue biochemistry. RESULTS: Ischemic fiber degeneration scores were found significantly lower in syringic acid and MP groups than sham group. Additionally, apoptosis-related cysteine peptidase caspase-3 immunostaining scores were lower in syringic acid and MP groups. Biochemically, superoxide dismutase and nuclear respiratory factor 1 values were significantly higher in syringic acid group compared to those of control and sham groups while malondialdehyde levels were significantly lower in the syringic acid group. CONCLUSION: Syringic acid reduces oxidative stress and axonal degeneration in rat sciatic nerve after ischemia/reperfusion injury. Therefore, syringic acid may play a role in the treatment of peripheral nerve injuries due to ischemia/reperfusion.

Comparison of Anterior Cervical Discectomy Fusion Techniques: Bladed and Non Bladed PEEK Cages.

AIM: The aim of this study is to compare the different types of fusion materials known as PEEK cages used during anterior cervical discectomy (ACD) surgery. MATERIAL AND METHODS: A total of 67 patients were operated and evaluated retrospectively under two groups (group A: 35 PEEK cage patients, group B: 32 bladed PEEK cage patients) between 2009 and 2013. Preoperative and postoperative (postoperative first day, postoperative 1st, 3rd and 12-24th mo) images were obtained. The cervical disc heights, cervical and segmental lordotic angles of the operated levels were calculated. Pain assessment was performed and fusion rates were also compared. Mann-Whitney U test was applied to compare the outcomes. RESULTS: The pain scores (especially for arm pain) were decreased significantly in both groups after surgery regardless of the type of operation technique (P < 0.05). There were no significant differences between both groups at the disc height measurements of operated levels in postoperative periods (P > 0.05). In addition to these; there was no significant difference between both groups of segmental and cervical lordodic angles in postoperative periods (P > 0.05). There was no statistically significant difference between the fusion rates and pain scores of both groups (P > 0.05). CONCLUSION: The PEEK cage and bladed PEEK cages can be used safely to obtain fusion after ACD.

Effect of Using High-Speed Drill in Anterior Cervical Discectomy and Fusion.

AIM: The objective of this study was to investigate the effect of using 2 different surgical techniques (curette or high-speed drill) in anterior cervical discectomy surgery on the healing of cases. MATERIAL AND METHODS: Fifty-four operated cervical disc hernia cases were retrospectively examined in 2 groups. Discectomy and osteophytectomy were carried out in Group A by using a high-speed drill, while a curette was used for group B. Preoperative and postoperative computerized tomography and direct radiography were performed. Cervical disc height, cervical and segmental lordotic angles were calculated. The visual analogue scale and Odom's criteria were used in the assessment of pain and clinical healing. The fusion ratio of both groups was compared. The Mann-Whitney U test was used to compare data from the groups. RESULTS: Satisfactory results were obtained in the groups where high-speed drill and curette were used. Independently from the surgical technique, pain scores were significantly reduced in both groups after surgery. No radiologically significant differences were identified between the two groups within the postoperative period. CONCLUSION: Either high-speed drill or curette can be chosen for the osteophytectomy and discectomy stages of anterior cervical discectomy operations.

Chronic intradiploic hematomas of the skull without coagulopathy: report of two cases / Hematoma crónico intradiploico sin coagulopatía: informe de 2 casos

Background: Chronic intradiploic hematoma was first described by Chorbski and Davis in 1934. To date, only twelve cases have been reported in the literature. Chronic intradiploic hematomas have also been described as non-neoplastic cysts of the diploe, traumatic cysts, and giant cell repetitive granulomas. The term chronic intradiploic hematoma was coined by Sato et al. in 1994. Case description: Case 1: a 16-year-old male presented with a non-tender scalp swelling on the right fronto-orbital region. Computed tomography (CT) scans showed an intraosseous isodense lesion with surrounding sclerosis. Magnetic resonance imaging (MRI) results revealed an intradiploic mass with homogeneous cystic and abnormal signal intensities. Case 2: a 64-year-old male presented with a 6-month history of headaches and visual disturbances. CT scans showed an isodense lesion with surrounding sclerosis in the posterolateral left orbit. MRI results revealed a hypointense lesion on both the T1weighted and T2-weighted images of the posterolateral left orbit. Conclusion: Although rarely seen, the presence of a benign chronic hematoma should be considered as part of the differential diagnosis for each intradiploic mass lesion. When taking the medical history, all patients with such mass lesions should be asked about previous minor or major head traumas. Due to the possibility of progressive growth, surgical excision of an intradiploic hematoma is recommended after radiological diagnosis of the condition

Antecedentes: El hematoma crónico intradiploico fue descrito por primera vez por Chorbski y Davis en 1934. Hasta la actualidad solo se han publicado 12 casos en la literatura. Los hematomas crónicos intradiploicos también se han descrito como quistes no neoplásicos del diploe, quistes traumáticos y granulomas repetitivos de células gigantes. El término hematoma crónico intradiploico fue acuñado por Sato et al. en 1994. Descripción de los casos: Caso 1: Varón de 16años que consultó por hinchazón no dolorosa en región frontoorbitaria derecha. La tomografía computarizada mostró una lesión intraósea isodensa con esclerosis circundante. La resonancia magnética (RM) reveló una masa intradiploica con quiste homogéneo de señal anormal. Caso 2: Varón de 64años que consultó por historia de 6meses de dolor de cabeza y alteraciones visuales. La tomografía computarizada craneal mostró una lesión isodensa con esclerosis circundante en la región posterolateral de la órbita izquierda. La RM mostró una lesión hipointensa tanto en las secuencias TI como T2 de la porción posterolateral de la órbita izquierda. Conclusión: A pesar de su rareza, la presencia de un hematoma crónico benigno debe considerarse en el diagnóstico diferencial de cada lesión masiva intradiploica. A los pacientes con este tipo de lesiones de masa se les debe interrogar sobre el antecedente de trauma craneal previo mayor o menor. Debido a la posibilidad de crecimiento progresivo, se recomienda la extirpación quirúrgica del hematoma intradiploico una vez realizado el diagnóstico radiológico de la enfermedad

Spontaneous Regression of Lumbar Disc Herniation After Weight Loss: Case Report.

Diagnosis, treatment, and surgery for lumbar disc herniations have existed for over a century. However, during the last three decades, there have been many new developments in imaging techniques, surgical procedures, physical medicine, and rehabilitation. In light of this, the most effective and appropriate treatment is controversial. Spontaneous regression of sequestrated, extruded, or protruded disc herniation has often been reported in the literature, although it is still a rare phenomenon. After a thorough review of the literature, we did not find any case report about this phenomenon after weight loss. In this report, though, we present a recent case about spontaneous regression of extruded disc herniation following weight loss.

Chronic intradiploic hematomas of the skull without coagulopathy: Report of two cases.

BACKGROUND: Chronic intradiploic hematoma was first described by Chorbski and Davis in 1934. To date, only twelve cases have been reported in the literature. Chronic intradiploic hematomas have also been described as non-neoplastic cysts of the diploe, traumatic cysts, and giant cell repetitive granulomas. The term chronic intradiploic hematoma was coined by Sato et al. in 1994. CASE DESCRIPTION: Case 1: a 16-year-old male presented with a non-tender scalp swelling on the right fronto-orbital region. Computed tomography (CT) scans showed an intraosseous isodense lesion with surrounding sclerosis. Magnetic resonance imaging (MRI) results revealed an intradiploic mass with homogeneous cystic and abnormal signal intensities. Case 2: a 64-year-old male presented with a 6-month history of headaches and visual disturbances. CT scans showed an isodense lesion with surrounding sclerosis in the posterolateral left orbit. MRI results revealed a hypointense lesion on both the T1weighted and T2-weighted images of the posterolateral left orbit. CONCLUSION: Although rarely seen, the presence of a benign chronic hematoma should be considered as part of the differential diagnosis for each intradiploic mass lesion. When taking the medical history, all patients with such mass lesions should be asked about previous minor or major head traumas. Due to the possibility of progressive growth, surgical excision of an intradiploic hematoma is recommended after radiological diagnosis of the condition.

The Effect of Coumaric Acid on Ischemia-Reperfusion Injury of Sciatic Nerve in Rats.

The aim of the study was to determine the effect of coumaric acid on sciatic nerve ischemia/reperfusion (SNI) injury in rats. The rats were randomly divided into four groups: control group (no medication or surgical procedure), SNI group, SNI + coumaric acid (CA) group, and SNI + methylprednisolone (MP) group. Ischemia was achieved by abdominal aorta clamping, and all animals were sacrificed 24 h after ischemia. Harvested sciatic nerve segments were investigated histopathologically and for tissue biochemistry. A significant decrease in MDA, an increase in NRF1 levels, and increase in SOD activity were observed in the groups which received coumaric acid and methylprednisolone when compared to the corresponding untreated group (p < 0.05). Ischemic fiber degeneration significantly reduced in the SNI + CA and SNI + MP groups, especially in the SNI + MP group, compared to the SNI group (p < 0.05). Beta amyloid protein expressions were significantly decreased in the SNI + CA group compared to the SNI group (p < 0.05). Our study revealed that coumaric acid treatment after ischemia/reperfusion in rat sciatic nerves reduced oxidative stress and axonal degeneration. Therefore, coumaric acid may play a role in the treatment of peripheral nerve injuries due to ischemia/reperfusion.

Management of Type II Odontoid Fracture for Osteoporotic Bone Structure: Preliminary Report.

AIM: Anterior transodontoid screw fixation technique is generally chosen for the management of type II odontoid fractures. The nonunion of type II odontoid fractures is still a major problem especially in elderly and osteoporotic patients. Eleven osteoporotic type II odontoid fracured patients were presented in this article. MATERIAL AND METHODS: We have divided 11 patients in two groups as classical and Ozer's technique. We have also compared (radiologically and clinically) the classical anterior transodontoid screw fixation (group II: 6 cases) and Ozer's transodontoid screw fixation technique (group I: 5 cases) retrospectively. RESULTS: There was no difference regaring the clinical features of the groups. However, the radiological results showed 100% fusion for Ozer's screw fixation technique and 83% fusion for the classical screw fixation technique. CONCLUSION: In conclusion, we suggest that Ozer's technique may help to increase the fusion capacity for osteoporotic type II odontoid fractures.

Spinal Extradural Arachnoid Cysts: A Series of 10 Cases.

BACKGROUND AND OBJECTIVE: Spinal arachnoid cysts are rare lesions, accounting for only 1% of all primary spinal mass lesions. They can occur in extradural, intradural, or intramedullary locations. The extradural cysts are thought to arise from defects in the dura mater through which the arachnoid herniates. This report presents 10 cases of spinal extradural arachnoid cysts and discusses our diagnostic and therapeutic approach to this rare clinical entity. PATIENTS: The archive records of 10 patients with extradural arachnoid cysts who were treated between 2002 and 2009 were evaluated retrospectively. The study included four male and six female patients. In nine cases, the lesion was symptomatic; in only one case was the cyst diagnosed incidentally. Surgical treatment was performed in the nine symptomatic cases. RESULTS: In nine of these cases, the extradural cysts were solitary; in one case, multiple extradural cysts were observed. In most of the cases, the lesion was located in the thoracic region. Total excision of the cyst was achieved for all of the cases treated surgically except the case with multiple extradural arachnoid cysts. On follow-up examination, neurologic improvement was observed in all of the surgically treated patients. CONCLUSION: Spinal extradural arachnoid cysts are rare pathologies, and treatment options should be considered carefully. In symptomatic cases, total excision of the cyst should be considered the gold standard of treatment. We believe that the closure of the dural defect should be the main surgical goal to prevent recurrence. We propose laminoplasty for the treatment of extradural arachnoid cysts that involve multiple segments to prevent postoperative kyphosis.

The Neuroprotective Effect of Coumaric Acid on Spinal Cord Ischemia/Reperfusion Injury in Rats.

The main causes of spinal cord ischemia are a variety of vascular pathologies causing acute arterial occlusions. We investigated neuroprotective effects of coumaric acid on spinal cord ischemia injury in rats. Rats were divided randomly into four groups of eight animals as follows: control, ischemia, ischemia + coumaric acid, and ischemia + methylprednisolone. In the control group, only a laparotomy was performed. In all other groups, the spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. Levels of malondialdehyde and nuclear respiratory factor 1 were analyzed, as were the activity of superoxide dismutase. Histopathological and immunohistochemical evaluations were performed. Neurological evaluation was performed with the Tarlov scoring system. The ischemia + coumaric acid group was compared with the ischemia group, and a significant decrease in malondialdehyde and levels was observed. Nuclear respiratory factor 1 level and superoxide dismutase activity of the ischemia + coumaric acid group were significantly higher than in the ischemia group. In histopathological samples, the ischemia + coumaric acid group is compared with the ischemia group, and there was a significant increase in numbers of normal neurons. In immunohistochemical staining, hypoxia-inducible factor-1α and NF-kappa B immunopositive neurons were significantly decreased in the ischemia + coumaric acid group compared with that in the ischemia group. The neurological deficit scores of the ischemia + coumaric acid group were significantly higher than the ischemia group at 24 h. Our results revealed for the first time that coumaric acid exhibits meaningful neuroprotective activity following ischemia-reperfusion injury of the spinal cord.

The Neuroprotective Effect of Syringic Acid on Spinal Cord Ischemia/Reperfusion Injury in Rats.

Acute arterial occlusions via different vascular pathologies are the main causes of spinal cord ischemia. We investigated neuroprotective effects of syringic acid on spinal cord ischemia injury in rats. Rats were divided into four groups: (I) sham-operated control rats, (II) spinal cord ischemia group, (III) spinal cord ischemia group performed syringic acid, and (IV) spinal cord ischemia group performed methylprednisolone intraperitoneally. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores. A significant decrease was seen in malondialdehyde levels in group III as compared to group II (P < 0.05). Besides these, nuclear respiratory factor-1 and superoxide dismutase activity of group III were significantly higher than group II (P < 0.05). In histopathological samples, when group III was compared with group II, there was a significant decrease in numbers of apoptotic neurons (P < 0.05). In immunohistochemical staining, BECN1 and caspase-3-immunopositive neurons were significantly decreased in group III compared with group II (P < 0.05). The neurological deficit scores of group III were significantly higher than group II at twenty-fourth hour of ischemia (P < 0.05). Our study revealed that syringic acid pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required for syringic acid to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future.

Morphometric and ultrastructural analysis of the effect of bromocriptine and cyclosporine on the vasospastic femoral artery of rats.

Vasospasm is the main causes of mortality and morbidity in patiens with subarachnoid hemorrhage (SAH). The arterial narrowing mechanism that develops after SAH is not yet fully understood but many studies showed that hypotension, neurogenic reflexes, clots in the subarachnoidal space, spasmogenic agents, humoral and celluler immunity play a role in the etiology. In this study we investigate the effects of Bromocriptine and Cyclosporine A in vasospasm secondary to SAH on rat femoral artery from ultrastructural and morphometric perspectives. 120 male Sprague-Dawley rats divided into 12 groups: Vasospasm (V), control (K), surgical control (CK) groups, vasospasm+Bromocriptine and/or Cyclosporine-A groups (VCyA, VBr, VBr+CyA), Bromocriptine and/or Cyclosporine-A control groups (CK, BK, Br+CyAK), Bromocriptine and/or Cyclosporine-A surgical control groups (BCK, CyCK, Br+CyACK). In order to create SAH model, 0, 1 cm(3) blood injected into silastic sheath wrapped rat femoral artery. Bromocriptine (2 mg/kg/d) and Cyclosporine A (10 mg/kg/d) combinations applied to control, surgical control and vasospastic models. Light microscopy, transmission electron microscopy and scanning electron microscopy used during this study. Statistical evaluation of the morphometric measurement data concerning vascular wall thickness and luminal cross-sectional areas of all groups were performed using Mann-Whitney U, Wilcoxon-signed rank, and Student-t tests. Cyclosporine A, whose effects in the prevention of vasospasm have been demonstrated in previous studies. In this study we discovered that Bromocriptine demonstrated strong effects similar to Cyclosporine-A. Bromocriptine and Cyclosporine A markedly prevent the development of chronic morphologic vasospasm following SAH. The combined use of both drugs does not change this preventive effect.

Condensing osteitis of the clavicle in a man: any relationship with tooth decay?

Condensing osteitis of the clavicle is a rarely seen pathology since its first description in 1974. Although mechanical stress is claimed for aetiology, but remains a dilemma for physicians. The intermittent or steady pain is variable in intensity and generally localised at the medial end of the involved clavicle, supraclavicular fossa, ipsilateral anterior thorax and shoulder. In this report, we present a 28-year-old man with the regression of the condensing osteitis of the clavicle after the extraction of a decayed tooth.

Determining the morphometry and variations of the confluens sinuum and related structures via a silicone painting technique on autopsy patients.

In this study, we aimed to investigate the morphometric and morphologic structures of the confluens sinuum (CS) and related structures with a silicone painting technique. We studied 30 cadavers. Twelve of them were washed with alcohol and filled with a silicone painting technique via the vena jugularis interna, internal carotid artery, and vertebral artery. The other 18 were autopsied postmortem. The CS and related structures were dissected under microscope. Their anatomy was investigated, and variations were noted. The diameters of the sinus sagittalis superior (SSS), CS, occipital sinus (OS), sinus rectus (SR), and bilateral transverse sinus (TS), and the angle between SSS and SR were measured. The mean diameters were 11.7 mm for SSS, 22.3 mm for CS, 5.25 mm for OS, 7.5 mm for SR, and 9.7 (right) and 9.1 mm (left) for TS. The angle between the SR and SSS was 58°. There was no difference in the bilateral venous structures that drained to the SSS and TS. There was an extra drainage to the CS from the left side in 4 cases. The right TS was located superiorly in 7 cases compared with the left TS, and this process was correlated with the type of CS. A septum in the SSS was detected in 2 cases. In addition, we encountered an OS in 80% of the cases. We conclude that the septum inside the CS affects the dominancy of the TS, the angle between the SSS and SR, and the other venous variations.

Falcine venous plexus within the falx cerebri: anatomical and scanning electron microscopic findings and clinical significance.

BACKGROUND: Only limited attention has been paid to the anatomy and clinical importance of the falcine venous plexus. The aim of this study was to evaluate the falcine venous plexus anatomically using scanning electron microscopy (SEM), and to provide guidance for neurosurgical approaches. METHODS: Latex or ink was injected into the superior and inferior sagittal sinus. The falcine venous plexus lying within the connective tissue of the falx cerebri was observed by dividing the falx into thirds (anterior, middle and posterior). Further, the SEM appearance of the falcine venous plexus was evaluated. RESULTS: The anterior third of the falx cerebri consisted of small diameter falcine venous vessels. These vessels were localized close to either the superior or inferior sagittal sinus, and none extended as far as mid-falx cerebri levels in any of the 16 cases. They communicated with either superior or inferior sagittal sinuses, but not with both of these sinuses. In the middle third of the falx cerebri, the majority of the vessels of the falcine venous plexus had larger diameter compared to those of the anterior third. These vessels extended the length of the falx cerebri levels. They communicated with both superior and inferior sagittal sinuses. In the posterior third of the falx cerebri, the vessels of the falcine venous plexuses had the largest diameter and were located at the junction of the inferior sagittal sinus and the straight sinus. They were localized at the lower two-thirds of the falx cerebri. In all cases, the dense venous networks communicated with the inferior sagittal sinus but not with the superior sagittal sinus. The falcine venous plexus observed in the posterior third of the falx cerebri was denser than in the anterior and middle portions. The SEM revealed small vessels whose diameter ranged between 42 and 138 µm. The vessels of the falcine venous plexus in the anterior third had a mean diameter of 0.42 ± 0.1 mm, in the middle third a mean diameter of 0.87 ± 0.17 mm, and in the posterior third, 1.38 ± 0.21 mm. CONCLUSION: The falcine venous plexus is a network of venous channels that exists within the connective tissue of the falx; the sizes and patterns of communication of these structures showed regional differences. Neurosurgeons should be aware of the regional differences when making an incision or puncturing the falx during a surgical approach.

The role of exudation in chronic subdural hematomas.

OBJECT: Chronic subdural hematomas (SDHs) are a local inflammatory process that causes the formation of a granulation tissue often referred to as the external or outer membrane. This membrane has abnormally permeable macrocapillaries. Therefore, exudation from the macrocapillaries in the outer membrane of chronic SDH may play an important role in the enlargement of chronic SDH. In this study the authors investigated the role of exudation in chronic SDH. METHODS: The authors examined 24 patients (16 men and eight women; age range 38-86 years [mean age 61.4 years]) with 27 chronic SDHs. The clinical status of the patients was evaluated according to the classification described by Markwalder. The diagnosis was established on computed tomography (CT) scans in all cases. The authors also used the Nomura Classification for judging the lesion's appearance on CT scans. Immediately after the diagnosis, all patients were administered 20 mCi (740 mBq) technetium-99m human serum albumin. Four hours later, blood and SDH samples were taken and radioactivity levels were measured in each. The ratio of activity of the samples taken from chronic SDH to the radioactivity of blood was determined as a percentage and defined as the exudation rate. On the follow-up CT scan obtained on postoperative Day 20, subdural collections thicker than 5 mm were determined to be a reaccumulation. RESULTS: The correlations between the exudation rate and age of the patients, clinical grades, CT appearances, and amount of reaccumulation were investigated. In this series the average exudation rate was 13.24% (range 2.05-28.88%). The mean exudation rates according to the clinical grades assigned to patients were as follows: Grade 0, 8.67 +/- 5.64% (three patients); Grade 1, 5.07 +/- 1.43% (eight patients); Grade 2, 17.87 +/- 3.73% (seven patients); and Grade 3, 19.65 +/- 7.67% (six patients). Exudation rates in patients with Grades 2 and 3 were significantly higher than those in Grades 0 and 1 (p < 0.05). The mean exudation rates according to the lesion's appearance on CT scans were found as follows: hypodense appearance, 6.55 +/- 4.52% (eight patients); isodense appearance, 11.07 +/- 6.32% (five patients); hyperdense appearance, 19.47 +/- 13.61% (three patients); and mixed-density appearance, 17.40 +/- 5.80% (nine patients). The differences among the groups were significant (p < 0.05). The average exudation rate was statistically higher in the patients with reaccumulation (16.30 +/- 8.16%) than that in the patients without reaccumulation (9.96 +/- 6.84%) (p < 0.05). CONCLUSIONS: The exudation rate in chronic SDH is correlated with a higher clinical grade (Markwalder Grade 2 or 3), mixed-density CT appearance, and reaccumulation. Therefore, exudation from macrocapillaries in the outer membrane of chronic SDH probably plays an important role in the pathophysiology and the growth of chronic SDH.