Long-term outcomes of surgical management in subtypes of Chiari malformation.

Objective: Chiari malformations (CMs) are a heterogeneous group of disorders defined by anatomic anomalies of the cerebellum, brainstem, and craniovertebral junction (CVJ). The aims of this study are to establish the demographic and clinical features, incidence, surgical procedures, and outcomes in large series of old and new subtypes of CMs.Material and Methods: All patients were evaluated and operated on for CM-0, 1, and 1.5 between 1985 and 2016. The patients were grouped into various subtypes. Demographic data, additional diseases, clinical features, surgical procedures, complications and outcomes were recorded.Results: 191 patients who underwent various surgical procedures were evaluated. Their mean age was 37.21 ± 9.89. We detected 15 cases of CM-0 (7.8%), 121 cases of CM-1 (63.4%), 55 cases of CM-1.5 (28.8%). In total there were 191 cases, and 220 surgical procedures were performed. 29 (13.2%) of all surgical procedure was reoperations and secondary operations. SM Cyst is found to be decreased in 72 (76.5%) patients, unchanged in 14 (14.8%) and increased in 8(8.5%) of 94 patients radiologically. Clinical outcomes are better for 131 (65.8%), same for 31 (16.2%) and worse for 9 (15%).Conclusion: This study with 172 patients is a large series that includes CM-0, 1, and 1.5 subtypes. CM-1.5 also differs for symptom presentation and durations from CM-1. There are more neurological abnormalities in patients with SM. CVD alone are an effective, useful and safe surgical procedure for CM-0, CM-1 and CM-1.5. Surgical procedure, SM existence, and symptom duration have powerful effects on outcomes.

Decompressive craniectomy in traumatic brain injury: Transcranial Doppler sonography used as a guide.

BACKGROUND: Decompressive craniectomy (DC) is performed in the management of intracranial hyper-tension after traumatic brain injury (TBI). This study aims to investigate the effects of transcranial Dop-pler ultrasonography (TCD) measurements on the indication of decompressive surgery. METHODS: Sixteen TBI patients with a Glasgow Coma Score (GCS) <9 were included in this study. Intra-cranial pressure (ICP) monitoring and transcranial Doppler ultrasonography (TCD) measurements were recorded continuously. DC was performed according to the records of ICP and TCD. Glasgow Outcome Scale (GOS) scores were evaluated after three months. RESULTS: Mean age of the patients was 31.18±17.51; GCS ranged between three and 14 with a mean of 9.62±3.95. Mean GOS was 3.12±1.85. Craniectomy was performed in two patients (12.5%) and cra-niectomy and lobectomy together were performed in 14 (87.5%) of them. The decline in ICP (22.12±10.41, 22.62±7.35, 15.50±6.64) and pulsatility index (PI) (1.96±1.10, 1.64±0.75, 1.91±2.48) were strongly significant between days 3-5, and 1-5. The range of PI and Vmax values through five days did not present any significance. CONCLUSION: TCD, as a real-time monitor, may help for an early decision of surgical approach in the management of TBI patients.

Morphometric analysis of posterior fossa and craniovertebral junction in subtypes of Chiari malformation.

OBJECTIVES: Chiari malformations (CMs) are a group of disorders defined by anatomic anomalies of the cerebellum, brainstem, and craniovertebral junction (CVJ). In this study, we aimed to investigate morphometry of posterior fossa and CVJ in subtypes of CM and in control group, and to bring up a matter a correlation with demographic data and subtypes of CM. PATIENTS AND METHODS: The study group included patients managed for CM between 2012 and 2016 and control group. Radiological evaluation was studied by special programs and formulas. Intracranial volumes and morphometric datas of posterior fossa and CVJ were recorded retrospectively. RESULTS: Of the 141 patients, 91 had CM and 50 were control group participants. Mean age was 34.75. Patients were classified as CM-0 (n:10), CM-1 (n:45), CM-1.5 (n:21), CM-2 (n:15). There were statistically significance between Chiari subtypes by syringomyelia (SM) presence (p ˂ 0.01), SM localization (p ˂ 0.01), posterior fossa volume (PFV) (p ˂ 0.01), length of clivus (LoC) and length of subocciput (LoSO) (p ˂ 0.01 for both), angle between clivus and subocciput (C-SO angle) (p ˂ 0.01), and clivo-dental angle (C-D angle) (p ˂ 0.01). CONCLUSION: On morphometric comparison of CM subtypes we concluded that etiological differences lead to morphological differences. CM-2 has remarkable differences from both other subtypes and the control group.

Impact of 1p/19q codeletion on the diagnosis and prognosis of different grades of meningioma.

BACKGROUND: Meningiomas are one of the most common tumours to affect the central nervous system. Genetic mutations are important in meningeal tumourigenesis, progression and prognosis. In this study, we aimed to examine the effect of 1p/19q deletion on the diagnosis and prognosis of meningioma subtypes using the fluorescence in situ hybridization (FISH) method. METHODS: Twenty-four patients with meningioma were retrospectively studied. Tumour samples were obtained from 10 typical, 11 atypical and three anaplastic malignant meningiomas. The most representative tumour sections were screened for 1p/19q deletion using the FISH method. RESULTS: Of the 24 patients, eight were women (33.3%) and 16 (66.7%) were men. The mean age was 56.6 years. The higher-grade meningioma was usually seen in males and had a higher rate of deletion on 1p (p = 0.001). There was a statistically significant difference between the grades and the rate of deletion on 19q (p = 0.042) and between the grades and the rates of polysomy, monosomy and amplification on 19q (p = 0.002; p = 0.001; p = 0.002, respectively). There was no statistical difference between 1p/19q codeletion and the grades of meningioma (p > 0.05). We detected higher level of Ki-67 in the condition of codeletion but did not find a statistical difference (p = 0.0553). CONCLUSION: Deletion on 1p, as well as deletion, polysomy, monosomy and amplification on 19q, are detected more frequently in high grade meningiomas. This amplification is most likely due to the amplification of oncogenes.

The Acute and Delayed Effects of Vagal Nerve Stimulation on an Absence Epilepsy Model in WAG/Rij.

AIM: Vagal nerve stimulation (VNS) is an effective method of treatment for epilepsy patients either unresponsive to medical therapy or not suitable for resective surgeries. We designed an experimental study on Wistar Albino Glaxo rats from Rijswijk (WAGRij) to investigate the effects of VNS on a non-convulsive epilepsy model. MATERIAL AND METHODS: The experiment was performed on six WAG/Rij rats, a validated strain for genetic absence seizures. The animals were underwent VNS and the effects were investigated on electroencephalography (EEG) recordings at 22, 24, 26 hours of stimulation and 15 days after the cessation, for duration of spike and wave complexes (SWC), the numbers, mean duration of SWC and frequencies in an hour. RESULTS: EEG recordings demonstrated that the mean duration of SWC was 353.1 seconds and the number of activity per hour was 62 at the baseline. There were statistically significant decreases in the total duration of SWC and the number of activities (61.8% and 78% decrease, respectively). There were no significant decreases in the mean duration of SWC and the frequencies. CONCLUSION: The acute stimulation of the vagal nerve caused a statistically significant decrease both in overall duration of SWC and the number of complexes in an hour. Moreover, the positive effects seemed to last even 15 days after the cessation of the stimulation. Further studies focusing on different stimulation parameters and delayed effects of the VNS on human absence seizures are warranted.

Correlation between SPARC (Osteonectin) expression with immunophenotypical and invasion characteristics of pituitary adenomas.

Pituitary adenomas are the third most common intracranial tumors. Invasive adenomas account for only 0.1-0.2% of pituitary tumors. SPARC is a matrix glycoprotein that plays a role in progression and invasiveness of neoplasms. In this study, we examined the potential role of SPARC in invasive pituitary adenomas. Forty pituitary adenomas have been examined with histopathological and immunohistochemical techniques. The cohort has been classified into two groups as invasive (n = 25) and non-invasive (n = 15) utilizing the Hardy classification. Formalin fixed tissues have been stained with hematoxylin eosin. Ki-67, p53, and SPARC monoclonal antibodies have been used. We did not detect any significant difference on Ki-67, SPARC, and p53 expression patterns correlating with the pathological subtype or invasiveness. Only 24% of invasive adenomas had Ki-67 levels over 1%. A total of 67.7% non-invasive adenomas had Ki-67 levels below 1%. We did not detect any relation between SPARC levels and invasiveness of pituitary adenomas. Absence of significant SPARC expression in tumor progression, sellar dilatation, erosion and destruction suggest that SPARC scores are not related with invasiveness or progressiveness of pituitary adenomas.

Microsurgical fenestration and cystoperitoneal shunt through preauricular subtemporal keyhole craniotomy for the treatment of symptomatic middle fossa arachnoid cysts in children.

INTRODUCTION: The optimal surgical treatment for symptomatic middle fossa arachnoid cyst is still controversial. The most leading therapeutic options include cyst shunting and fenestration (endoscopic, microsurgical). We present our experience on surgical treatments of arachnoid cysts. PATIENTS AND METHODS: A retrospective data review of 16 children who underwent keyhole craniotomy for microsurgical fenestration and shunting of middle fossa arachnoid cysts between 1999 and 2012 was performed after institutional review board approval. The average patient age was 6.1 years. The average follow-up period was 36.5 months. There were ten male and six female patients in the series. Indications for surgery included intractable headaches (50%), increasing in cyst size (18.75%), and seizures (31.25%). All patient records were reviewed for their clinical presentation, classification, cyst resolution, symptom resolution, and cyst outcomes. After surgery, all patients underwent assessments of clinical and radiological improvement. RESULTS: Postoperative complications were observed in two cases: progressively resolving monoparesia in one case and resolving epileptic seizure with monotherapy in the other. All patients had a satisfactory clinical outcome, and in 87.5%, there was either a decrease in the size or a complete disappearance of the MFAC. Nevertheless, three (18.75%) of all patients needed shunt revision because of shunt dysfunction. Complication related to surgical technique was cerebrospinal fluid leak which spontaneously resolved in one patient. CONCLUSION: Microsurgical fenestration with keyhole craniotomy to provide passage between cysts to basal cisterns together with cystoperitoneal shunting during the same operation is still an effective and safe method in cases with symptomatic middle fossa arachnoid cysts in children.

Sturge-weber syndrome: a case report with persistent headache.

Sturge-Weber syndrome (SWS) is a rare congenital disorder characterized by a facial vascular nevus associated with an ipsilateral leptomeningeal angioma. Headache is a rare component of SWS and when it occurs it usually occurs as a migraine-like headache. We aimed to present a SWS patient with episodic tension type headache and to draw attention in different types of headaches that can be seen in SWS. A 21 year old female patient with the diagnosis of SWS was suffering from severe headaches. At her physical examination a facial nevus -occurred due to choroid angioma- was observed. On her neurological examination a mild asymmetry of upper extremities was visible. She had a 2 year history of frequent non-pulsating headaches. There was no nausea or aura like symptoms accompanying the headache. Headaches were lasting for hours. The pain was bilateral and pressing in quality. SWS are a very rare and challenging disease for both the patients and their families. Usually migraine type headache is seen in SWS but it should not be forgotten that more generalized headaches like tension type may also be seen.

The role of a single nucleotide polymorphism of the matrix metalloproteinase-1 gene promoter region in invasion and prognosis of meningiomas.

AIM: The matrix metalloproteinase (MMP) enzyme family has been shown to be active in tumorigenesis and tumor progression. In this study, we analyzed the prevalence of a guanine insertion in the MMP-1 gene promoter region in meningiomas and its effect on invasion and prognosis. MATERIAL AND METHODS: The study was performed with 33 meningioma patients. We also included 33 healthy patients in the study as a control group. The promoter area was amplified by polymerase chain reaction (PCR) following DNA isolation. The polymorphism was detected by restriction fragment length polymorphism (RFLP). RESULTS: According to the WHO classification of meningiomas, 87.9% of the affected patients were grade 1, and 12.1% were grade 2. In total, 72.7% of the meningioma patients (n=24) had at least one copy of the insertion (2G/1G or 2G/2G genotypes) and 27.3% (n=9) did not (1G/1G). There was no significant difference between the meningioma and control groups according to genotype distribution. CONCLUSION: In this study, the polymorphism in the matrix metalloproteinase-1 gene promoter region did not have an effect on the initiation, growth and progression of meningioma.

Spinal intradural hematoma and permanent paraparesis after a lumboperitoneal shunt operation: an unusual complication.

Pseudotumor cerebri is a condition of increased intracranial pressure in the absence of clinical, laboratory or radiological pathology. Spinal intradural hematoma formation after lumboperitoneal shunt (LPS) implantation is very rare, but it can cause sudden and serious deterioration. In this report, we present a patient who developed an intradural hematoma following LPS operation. A 27-year-old male patient suffering from headaches and progressive vision loss was diagnosed with pseudotumor cerebri. He underwent LPS operation in January 2009. Four hours after the operation, he developed urinary and fecal incontinence with paraparesis (1/5). Lumbar magnetic resonance imaging identified an intradural hematoma at the level of L2-L3, and he was reoperated. The intradural hematoma was removed. Physical therapy was started because of paraparesis. Two months later, the patient's muscle strength had increased to 3/5. Surgeons must remember that, LPS implantation can cause a spinal intradural hematoma in a small percentage of patients, with catastrophic results.

Desmoplastic infantile ganglioglioma: Report of an unusual case with a cranial defect.

Desmoplastic infantile ganglioglioma (DIG) is a rare tumor that typically occurs in infants under the age of 24 months. These tumors commonly have a good prognosis after surgical resection despite their aggressive radiological appearances. Clinical signs are due to the large size of the tumor and include increased head circumference, bulging fontanel, sunset sign and seizures. We report an unusual DIG case who presented with parietal bulging associated with a bony defect. The patient was thought to have a leptomeningeal cystic formation, but on his cranial magnetic resonance imaging (MRI), we observed a centrally and homogeneously gadolinium-enhanced lesion fixed to the dura by its solid component. A surgical gross total resection was performed, and no residual tumor was observed on follow-up.

A new molecule in aneurysmal subarachnoid hemorrhage: dendroaspis natriuretic peptide.

AIM: Dendroaspis natriuretic peptide (DNP) is the most recently identified member of the natriuretic peptide family. Although DNP has similar structure and function to other members, it is genetically different. The other members are known to cause vasorelaxation but the effects of DNP on vascular structure still remains unclear. In this study, we aimed to find out the role of DNP in the development of vasospasm following aneurysmal SAH (subarachnoid hemorrhage). MATERIAL AND METHODS: DNP levels of 17 patients diagnosed with aneurysmal SAH and 25 volunteers as control were measured. All SAH patients were treated with aneurysm clip. Five ml of venous blood sample was obtained on postoperative 1, 3 and 7th days from each patient. Additionally, DNP levels were determined by obtaining cerebrospinal fluid (CSF) postoperative 1, 3 and 7th days. RESULTS: Statistically significant difference was observed between cerebrospinal fluid DNP levels on day 1 and day 3 (P < 0.05). CONCLUSION: This study suggests that DNP can be anticipated among molecules leading development of vasospasm. The findings of present study are believed to encourage further studies regarding receptors and receptor specific drugs.

Investigation of ACE genome insertion/deletion correlation with immunohistochemical profile in pituitary adenomas.

AIM: The deletion polymorphism of the angiotensin-converting enzyme (ACE) genome causes neoplastic development in several organs by increasing the angiotensin 2 (A2) formation. In this study, we aimed to identify the ACE genome insertion/deletion polymorphism in pituitary adenomas and to compare it with the control group. MATERIAL AND METHODS: Patients operated for pituitary adenomas were included in the study. Genomic DNA was extracted from tumoral tissues and peripheral blood samples of the patients by using the Miller method. Primary sequence was selected via targeting the polymorphic region of intron 16 of ACE genome 17q23. DNA samples were multiplied by PCR using HACE3s and HACE3as primers. RESULTS: Twenty-one operated cases were studied. In the study group; 44 % of the patients were identified as D/D, 33% of them as I/D and 23% of them as I/I. In 60%, D allele was identified. According to immunohistochemical investigation, we found that 100% of the patients with Cushing adenoma were D/D alleles. CONCLUSION: Presence of high rate of ACE genome deletion in patients with pituitary adenoma and grade 3-4 patients suggest that ACE genome polymorphism can be a risk factor for the development of pituitary adenomas.

Microsurgical management of non-neurofibromatosis spinal schwannoma.

INTRODUCTION: The aim of this study is to assess the clinical properties and surgical results of patients diagnosed with spinal schwannomas without neurofibromatosis (NF) properties. PATIENTS AND METHODS: The data obtained from 35 patients who underwent resection of spinal schwannomas were analyzed. All cases with neurofibromas and those with a known diagnosis of NF Type 1 or 2 were excluded. 35 patients underwent surgery for spinal schwannoma at our institution between January 1997 and 2010. The data were gathered retrospectively from medical records and included clinical presentation, tumor location and post-operative complications. All cases were surgically excised, and they were confirmed to be schwannomas by pathologists with histopathological sections in paraffin stained with hematoxylin-eosin. RESULT: We treated 35 (20 males and 15 females) patients with spinal schwannomas. The mean age of the patients was 47.2 (between 13 and 76) years. Of the cases, six schwannomas were located in the cervical spine, four in the thoracic spine, two in cervico-thoracic area, 10 in the thoraco-lumbar area and 13 in the lumbar spine. Two patients had malignant schwannomas that were recurrent. Of the 35 cases, the schwannomas were intradural-extramedullary in 30 cases (86%), intradural-intramedullar in 2 cases (6%), and extradural in 3 cases (9%). CONCLUSION: Spinal schwannomas may occur at any level of the spinal axis and are most frequently intradural-extramedullary. The most common clinical presentation is pain. Most of the spinal schwannomas in non-NF patients can be resected completely without or with minor post-operative deficits. This knowledge may help us to create a strategy for total resection of a spinal schwannomas.

Long-term results and complications of the syringopleural shunting for treatment of syringomyelia: a clinical study.

BACKGROUND: The use of drains in the treatment of syringomyelia has a simple and immediate appeal. Syringopleural shunting in syringomyelia has produced good short-term results, but limited information is available on long-term effects. We analyzed the complications and long-term outcomes after syringopleural shunting for syringomyelia. CLINICAL MATERIAL AND METHODS: Fourthy-four patients with large-sized syringomyelia underwent syringopleural shunting because of spinal cord compression between 1992 and 2010 in our clinic. Thirty-two patients had Chiari malformation type I (Group B), and 12 patients were associated with primary parenchymal cavitations (Group A). Their ages ranged from 14 to 71 years. Both craniovertebral decompression and syringopleural shunting were performed on 21 patients, whereas only syringopleural shunting was performed on another 21 patients. RESULTS: The follow-up period ranged from 1 year to 17 years (mean: 9.1 years). There was no operative mortality. Early postoperative MRI revealed that syringes of 43 patients had collapsed. There were 9 (20.5%) minor complications in 9 patients, including temporary neurological deficits (6), respiratory distress (2) and headache (1). Seven (15.9%) serious complications [permanent neurological deficit (1), shunt migration (2), shunt misplacement (1), spinal instability (1), tethering (1), CSF over drainage (1)] were seen in five patients. Four of them were treated with a secondary operation. Three patients (3/9; 33.3%) who were treated by syringopleural shunt alone (Group B2) required craniovertebral decompression, although the shunt was functional. During long-term follow-up, three patients stabilized, five patients (11.3%) developed a worse neurological condition, and two of these patients died 10 and 7 years after surgery. Of all patients, 88.6% showed significant clinical improvement. CONCLUSIONS: Although there were complications and failures, syringopleural shunting produced satisfactory results at long-term follow-up.

Noninvasive estimation of cerebral perfusion pressure with transcranial Doppler ultrasonography in traumatic brain injury.

AIM: In traumatic brain injury (TBI) patients, to overcome the secondary insults, cerebral perfusion pressure (CPP) oriented therapy is recommended. The study is assigned to estimate CPP values with middle cerebral artery (MCA) flow velocities measured noninvasively using transcranial Doppler ultrasonography (TCD). MATERIAL AND METHODS: Forty-seven TBI patients were studied. Intracranial pressure (ICP), mean arterial pressure (MAP) and MCA flow velocities of the patients were monitored. Invasive CPP was calculated as the difference between MAP and ICP. The formula : 'MAP x FVd/FVm +14' was used to estimate CPP noninvasively. Correlation of the noninvasive and invasive values were analysed. RESULTS: The mean values of noninvasive CPP and invasive CPP were 66.10 ± 10.55 mmHg and 65.40 ± 10.03 mmHg respectively. The correlation between noninvasive and invasive CPP measurements was strongly significant (p < 0.001) with a correlation coefficient of r = 0.920. CONCLUSION: With ICP monitoring systems, CPP is calculated and the therapy is guided according to these values. As it is recognized that brain perfusion can be assessed with TCD waveforms, noninvasive CPP estimation with MCA flow velocities may help to observe the trends in CPP values.

A new entity: Chiari Zero malformation and its surgical method.

Recently, Iskandar et al described "Chiari Zero malformation" to characterize some kind of syringomyelia that exhibits classic Chiari-type symptoms with little to no herniation, but there is some dilemma about whether it is actually present. We presented a 38-year-old-man with a diagnosis of cervical syringomyelia. In his neurological examination, there was monoparesia at the left leg together with hypoesthesia below thoracal 7. He had initially been treated with syringopleural shunting successfully. Nine months after surgery, his syringomyelia had regrown and he clinically deteriorated. It was accepted as "a Chiari zero malformation". We performed craniovertebral decompression only. Although there was no tonsillar herniation, his syringomyelia was completely resolved and his neurological status was improved six months after the craniovertebral decompression, This case suggested that "Chiari zero malformation" description is remarkable and craniovertebral decompression is a suitable surgical approach for this entity.

Surgical treatment of huge congenital extracranial immature teratoma: a case report.

Congenital cranial teratomas are usually characterized by complete loss of the normal intracranial architecture. In the majority of reports, the tumors are associated with stillbirth, perinatal death, or significant morbidity after surgical resection. The few reported attempts at total or subtotal tumor resection have had poor outcomes, although there are rare reports of prolonged survival up to 3.5 years following resection of smaller tumors. Neonatal teratomas are rarely located in the scalp. In the literature, there were only a few patients who underwent surgery during the neonatal period with a good outcome; however, all such patients survived. In this paper, we present a neonatal case of huge congenital extracranial immature teratoma on the scalp extending to the orbita, ears, and brain. Examination of the patient revealed a large craniofacial mass and head circumference that was bigger than normal; there were no other neurological deficits. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a multiloculated, heterogeneous cystic mass that was larger than the patient's head, displacing and distorting anatomical structures. MRI showed mass with calcifications, soft tissue, fat, and fluid components. There was deformity and remodeling of the adjacent calvaria. A total surgical excision was performed and histopathological examination showed immature teratoma. The patient's early postoperative course was uneventful. Postoperative CT and MRI were normal. To date, the patient has survived for 6 months without neurological deficit. We conclude that acceptable functional outcomes in the context of massive congenital craniofacial teratomas can be achieved by early radical resection.

Currarino triad: surgical management and follow-up results of four [correction of three] cases.

The Currarino syndrome is a rare triad that is a combination of a presacral mass, a congenital sacral bony abnormality and an anorectal malformation. We present 4 children with complete Currarino triad who were diagnosed using MRI. Our aim was to report the neurosurgical management of Currarino syndrome in children. All of the patients had chronic constipation and pain in the lumbosacral region. In the plain radiograph, 3 patients had a sacral scimitar-shaped bony abnormality, and 1 patient had total sacral agenesis. There was a narrow anal canal or narrow ventrally displaced anus in all patients. Their anorectal malformations were characterized as anal stenoses (4 patients), associated with Hirschsprung's disease in 2 cases. In 3 patients, MRI showed tethered cord syndrome in addition to the presacral mass. There was hydrocephalus in 1 patient. Anal stenosis was treated by anal dilatation. In 2 patients, rectal biopsy and temporary colostomy (2 patients) had been performed previously due to Hirschsprung's disease. We performed a posterior procedure via lumbar and sacral partial laminectomy-laminoplasty and transdural ligation of the neck of the meningocele for anterior sacral meningoceles, or alternatively, tumor excision for other types of presacral lesions. Histopathologically, 3 were cases of anterior sacral meningoceles and 1 was a teratoma. One of them also had a spinal abscess. He required reoperation (twice) and appeared at the time to have improved with medical therapy. All patients improved and stabilized. There were no additional neurological deficits and no recurrence of the presacral mass over the follow-up period (6 years, on average). The family pedigree did not reveal any familial transmission pattern. In cases of Currarino triad, MRI can allow the characterization of the presacral masses. If it is an anterior sacral meningocele or a solid tumor without severe anorectal malformation, it can be managed with posterior lumbar and sacral procedures. Such approaches are performed easily by transdural ligation of the neck of the anterior sacral meningocele or through tumor excision.

Microsurgical and histomorphometric study of the occipital sinus: quantitative measurements using a novel approach of stereology.

Quantitative descriptions of the occipital sinus are lacking in the extant medical literature. Posterior fossa duras with the superior sagittal sinus, the inferior and superior petrosal sinuses were dissected and taken out from fresh human cadavers by cutting at the superior sagittal sinus, the marginal sinuses and the petrosal sinuses bilaterally. The length of the occipital sinuses was measured using calipers. A 0.5-cm section of the occipital sinus was cut out at its midpoint and prepared for measurements of the perimeter and diameter using a stereology workstation. The sinuses were also examined qualitatively using a surgical microscope. There was no occipital sinus in 6.6% of total 30 cases. Multiple occipital sinuses were seen in 10%. In one specimen, the sinus seemed incomplete, failing to reach the marginal sinuses. Some specimens gave the impression that more than one occipital sinus was present, nevertheless, careful dissection showed connections. The breadth of the sinus steadily narrowed downward in direction of foramen magnum. The inner wall with many fibrous bridges was tight, except the lateral parts that were easily separated into two dural sheets. The length of the sinus varied from 10 to 37 mm. The inner diameter (feret maximum) varied from 0.33 to 7.06 mm at midpoint. The breadth of the multiple sinuses did not exceed the mean of our series except in one case. The occipital sinus, which is generally ellipsoid in shape, functions in the majority of cases as a thin, single midline sinus. It may have less resistant recesses laterally.