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تم العثور علي : 14
 تم العثور علي : 14
  
 
إعادة البحث

Thesis 2020

Periodical 2020
ع.4 (2020) /

Thesis 2000.
The neurovascul ar relationships in the region of the tentorial incisura are among the complex in
the cranium . The incisura! area is related to the depths of the cerebrum and the cerebellum
- six
cranial nerves
- the upper brain stem - the cricle of Willis and the convergence of the deep
intracranial venous system to form the vein of Galen. It is exposed during many operations for
aneurysms
- deep tumours - arteriovenous malformations - trigeminal neuralgia and epilepsy.
The incisura! area is subdivided according to the relation to the brain stem into four spaces :
anterior
- paired middle and posterior incisura! spaces.
Prior to the development of microsurgical techniques
- the operative mortality rate for surgical
treatment of different incisura! lesions was extremely









high. Even with the










operating









microscope and advanced










microneurosurgical instrumentation . It still remains technically challanging for the neurosurgeon.
With the advent of improved imaging tools and techniques such as computerized tomography CT and
magnetic resonance imaging MRI . Lesions of the tentorial
incisura are diagnosed earlier and more precisely than in
the pre CT era.
An accurate preoperative localisation of the lesion IS necessary before an operative approach and
possible recostruction can be planned .The essential issues that guide the evaluation of incisura!
lesions include; the anatomical localisation and extent
- the lesion composition and biology - its
relation to major vessels the surgeon’s preference or expenence and/or the patient’s history of
prior therapy.
The surgical approaches to tentorial incisura}

lesions are classified according to different incisural
spaces into :
Approaches to the anterior incisura! space include; the unilateral and bilateral subfrontal
approach
- the anterior interhemispheric approach - the frontolateral approach - the fronto-orbital
approach
- the trans­ sphenoidal approach - the combined subfrontal trans­ sphenoidal trans-lamina
terminalis approach
- the fronto­ temporal approach - the sup aorbital pterional approach - the
cranio-orbito -zygomatic approach and the extradural tempropolar trans-cavernous approach Approaches to the middle incisura! space include; the classic subtemporal approach
- the zygomatic
approach
- the extended middle cranial fossa approach - the presigmoid approach - the combined
presigmoid with otico-condylar osteotomy
- and the suboccipital retrosigmoid suprameatal approach.
Approaches to the posterior incisura! space include: the supracerebellar infratentorial approach
-
the posterior interhemispheric approach
- the occipital transtentorial approach and the combined
supra-infratentorial trans­ sinus approach .
Nevertheless radical cranial base approaches are well established and their features are widely
recognized
- yet there is evoLution of minim ally invasive surgical approaches - which are the result
of technology that provides opportunities to view the operative field throu gh improved
illumination and magnification. Although they pose a great challenge to surgeon’s ability
-
minimally invasive surgical techniques can approach intracranial lesions with minimal retraction or
compression of normal neural structures.so it is suitable for high risk patients
- elderly patients
and children who must undergo major surgery

Thesis 2016.

Thesis 1981.

Thesis 2013
Hematopoietic stem-cell transplantation (HSCT) offers a unique opportunity for long-term disease control to many patients with severe malignant or non-malignant - acquired or congenital disorders of the hematopoietic system - or with chemo-sensitive - radiosensitive or immuno-sensitive tumors. Stem cells from peripheral blood - bone marrow or cord blood are used as the graft product. HSCT has seen rapid expansion over recent decades. It is considered the treatment of choice in several circumstances - and it is integrated into the treatment algorithm for many disease categories from diagnosis.
Still
- HSCT is associated with substantial morbidity and mortality. Patients and treating physicians face the challenge of deciding for or against a treatment with early risks of transplant-related mortality but the late benefit of long-term disease control. The dilemma increases when relatively non-toxic alternative therapies are available - even when their long-term benefit is yet unclear. However - most of complications could be predicted by proper assessment & so - could be prevented or at least decrease its severity.
Comorbidities are defined as any concurrent health condition or process that coexists with or may occur during the clinical course of a patient with a primary (index) disease or procedure that is being studied. Comorbidities can affect the moment of detection
- prognosis - therapy and patient outcome in a variety of diseases.
Patients with liver dysfunction have an increased risk of developing early and late complications after hematopoietic stem-cell transplantation (HSCT). That’s why it is mandatory to evaluate liver status before transplantation in all cases. This evaluation should allow us to decide whether HSCT can be performed or whether we should adopt measures focused on preventing these complications. The evaluation of the liver in an HSCT candidate requires the collection of information by history-taking
- physical examination - liver-function tests and - occasionally - imaging tests and liver biopsy. Additionally - as infection by hepatitis B or C viruses represents the most relevant cause of hepatic dysfunction after HSCT - the serological status of the patient should be carefully evaluated.
HBsAg + patients with an active hepatitis have an increased risk for VOD in the early phase after HSCT
- recovery of cellular immunity 3-6 months after HSCT can result in HBV re-activation with a biochemical hepatitis that in up to 12% of cases can be fulminant.
Recommendations: If physical examination or LFTs suggest a chronic liver disease
- try to perform a liver biopsy. If severe hepatic fibrosis or cirrhosis exists - HSCT using high-dose chemo-radiotherapy is contraindicated. If AST/ALT are normal; HSCT not contraindicated (no higher risk of VOD). If AST/ALT are increased; try to delay HSCT (increased risk of VOD).
In all cases test HBeAg
- anti-HBe and HBV DNA:
a. All HBV DNA-positive patients should receive prophylactic antiviral therapy (lamivudine 100 mg/day orally during immunosuppression).
b. If HBV DNA-negative: monitor after HSCT and start antiviral therapy if becomes positive.
c. If pre-core mutant form (HBeAg
- anti-HBe+‏ - HBV DNA‏+) there is increased risk of fulminant hepatic failure - so use prophylactic antiviral therapy.
In HBsAg- but anti-HBc+ and anti-HBs± patients; possible HBV reactivation is up to 20% of patients (reverse seroconversion). Recommendations are to test HBV DNA after HSCT and consider antiviral therapy if it becomes positive.
In HCV DNA + patients: some but not all authors have found association with HCV infection and VOD risk. Recovery of cellular immunity 3-6 months after HSCT can result in an HCV reactivation with biochemical hepatitis
- but fulminant cases are exceptional. Although the long-term expected incidence of cirrhosis in these patients was considered low (<5%) - a long-term follow-up has shown an incidence of 24% at 20 years.
Recommendations: If physical examination or LFT suggest chronic liver disease
- try to perform a liver biopsy. If severe hepatic fibrosis or cirrhosis exists; HSCT using high-dose chemo-radiotherapy is contraindicated. If there is chronic hepatitis with neither severe fibrosis nor cirrhosis; HSCT is not contraindicated. If AST/ALT are normal; HSCT is not contraindicated. If AST/ALT are increased; try to delay HSCT (increased risk of VOD) ; if it cannot be delayed ; consider treatment with ribavirin - interferon or peginterferon.
Cytomegalovirus (CMV) remains a major pathogen for solid organ transplant recipients
- causing febrile syndromes - hepatitis - pneumonitis - retinitis - and colitis. Because CMV produces lifelong latent infection - differentiation of latent infection from active disease in immuno-compromised individuals presents a diagnostic challenge. All allogeneic bone marrow recipients are at risk for CMV pneumonia after HCT; however - the risk is highest in sero-negative recipients who receive marrow from a seropositive donor. Other risk factors include viral shedding from other sites - viremia - chronic steroid use - and GVHD. The use of sero-negative blood products and leukocyte–depleted platelets greatly reduces - but does not eliminate the risk of developing CMV pneumonitis in sero-negative recipients.
Although HSCT-associated cardiac toxicity has become less common in recent years using modern regimens
- a wide range of incidences of mortality and morbidity are still being reported in small and large series of patients. As a general rule - an ejection fraction of ≥35-40% has been accepted as reasonable evidence of adequate cardiac reserve for HSCT. Ejection fraction does correlate weakly with survival and functional status; however - haemodynamic status - functional status - N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin are all independent predictors of prognosis and merit consideration when deciding who is fit for HSCT. Tissue perfusion - especially of the brain - correlates better with symptomatic status and biochemical markers of heart failure than ejection fraction.
Baseline pulmonary function tests should be performed prior to allogeneic HCT. A decreased diffusing capacity or an increased alveolar–arterial oxygen gradient
- are independent risk factors for interstitial pneumonitis and for overall mortality after transplantation. Nevertheless - these findings alone should not preclude HCT - since they are less predictive of outcome than other factors - such as relapse status and the degree of donor–recipient HLA matching. Furthermore - there is no level of pulmonary function abnormality that is uniformly predictive of death - and many patients referred for allogeneic HCT have no other viable treatment options.
Age is a poor predictor of BMT outcome in both allogeneic and autologous transplantation. Pediatric patients may have a better outcome when compared to adults. Older adults may have a somewhat higher risk of transplant-related mortality than do younger adults. However
- no study has definitively established a chronologic age at which the risk of the transplant is prohibitive. Age by itself should not be used as criteria to include or exclude a patient from Transplant.

Articles
VOL.5, NO.2, DEC. 2004 ,VOL.5, NO.2, DEC. 2004 / PP 136-148

Thesis 1998.

Book 1968 .

Thesis 2006


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