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PURPOSE: To perform endoscopic sinus surgery safely and effectively, surgeons need to visualize the complex anatomy of the anterior ethmoid and frontal sinus region. Because this anatomy is so variable and individualized, the foundation of understanding lies in identifying, following, and visualizing the drainage pathway patterns and anticipating possible variations. METHODS: We studied 100 sides (50 cases: 22 male, 28 female, aged 12-86, average age 46.5 years, ± 19.5) using computed tomography (CT) and multiplanar reconstruction (MPR) to identify and classify the drainage pathways leading to the frontal sinus and anterior ethmoidal cells. RESULTS: Analysis revealed five patterns of drainage pathways defined by their bony walls: between the uncinate process and the lamina papyracea [UP-LP]; between the uncinate process and the middle turbinate [UP-MT]; between the uncinate process and the accessory uncinate process [UP-UPa]; between the uncinate process and the basal lamella of the ethmoidal bulla [UP-BLEB]; and between the basal lamella of the ethmoidal bulla and the basal lamella of the middle turbinate [BLEB-BLMT]. In most cases, BLEB formed the posterior wall of the drainage pathway of the frontal sinus, indicating BLEB could be one of the most important landmarks for approaching the frontal sinus. CONCLUSIONS: As endoscopic sinus surgery depends on an understanding of this anatomy, this study may help surgeons to identify and follow the drainage pathways more accurately and safely through the anterior ethmoid to the frontal sinus.

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Background: The endoscopic endonasal approach to removing lesions in the nasal cavity and sinuses has become the modern first choice. However, if endoscopic surgery is performed without proper knowledge of sinus anatomy, there is a risk of residual lesions, recurrence, and even serious complications. Therefore, this article illustrates the importance of precise sinus opening guided by the natural sinus drainage pathway, using the anatomy of the frontal sinus (FS) and the frontal recess (FR) cells as an example. Method: A total of 82 sides cadaveric heads were dissected and analyzed, and the natural drainage pathways of the FR cells and FS were observed at 0°and 70°nasal endoscopic views, and the findings were summarized. The data of 79 patients who accepted endonasal endoscopic surgery (EES) guided by natural sinus drainage pathways to remove mucoceles in our department from January 2015 to January 2021 were retrospectively analyzed. Results: Two natural drainage pathways of the FR cells were discovered, identified, and named the medial pathway of the FR (MPFR) and the lateral pathway of the FR (LPFR). The 79 patients who accepted EES to remove mucoceles through the natural drainage pathways of FR cells and the FS showed significant improvement in clinical symptoms, and none of them had recurrence after surgery without serious complications. Conclusion: The EES of the FR cells and FS through the natural drainage pathways to remove the mucoceles facilitates exposure of the cells without residual lesions and without serious complications.

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PURPOSE: To investigate the anatomical features of frontal recess (FR) drainage, and the classification of FR cells and frontal sinus (FS). METHODS: Fifty sides from 30 adult cadaver heads were examined. FR cells and FS along the drainage pathways were dissected under 0° and 70° endoscopic views using unique connecting structures between the uncinate process and the ethmoid bulla as landmarks. RESULTS: Connecting plates between the uncinate process and the ethmoid bulla were discovered and termed medial suprainfundibular plate (MSIP), which were observed on each cadaver head, and lateral suprainfundibular plate (LSIP) on 92% (46/50) sides. Separated by MSIP, two drainage pathways were identified and named medial pathways of the FR (MPFR) medial to the MSIP and the lateral pathways of the FR (LPFR) in the lateral side. Different drainage pathways of the FS were confirmed, in which drained into the MPFR in 37 and into the LPFR in 13 of the cadaver sides. CONCLUSIONS: MSIP is the critical landmark for the recognition of MPFR, LPFR, and the classification of FR cells. The FR resection along LPFR and MPFR facilitated excellent exposure of FS.

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Cerebral amyloid angiopathy (CAA) is commonly found in older people and in patients with Alzheimer's disease (AD) accompanying cerebrovascular disorders and dementia. Early-onset CAA cases generally have been found only in rare genetic forms of CAA. Interestingly, however, CAA-related hemorrhages have been recently reported in younger people who had histories of neurosurgery with or without evidence of cadaveric dura mater grafts in childhood. It has been established in experimental settings that amyloid ß-protein (Aß) pathology can be transmitted inter-individually with Aß seeds. Incidental Aß pathology, predominantly Aß-CAA, has been recognized in recipients of cadaveric dura mater grafts or cadaveric human growth hormone. These findings suggest that transmission of Aß seeds through dura mater grafts and other contaminated materials could lead to development of CAA. In addition, neurosurgery or brain injury may contribute to cerebrovascular Aß deposition through the disturbance of vascular Aß drainage pathways. Thus, a novel concept, "acquired CAA," has emerged.

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Lateral and sigmoid sinus malformations are uncommon and dangerous anatomical variations that surgeons may encounter when performing a retroauricular approach. We report three cases of rare temporal bone venous sinus anomalies seen in patients who underwent cochlear implant surgery. The first patient had a diagnosis of CHARGE syndrome and presented a bilateral persistent petrosquamosal sinus with sigmoid sinus agenesis, which made mastoidectomy for cochlear implantation difficult. The second patient presented an anomalous venous lake in the occipital region, which communicated the left dural venous sinuses with a conglomerate of pericranial vessels in the left nuchal region, also consistent with left sinus pericranii. The third patient presented with an extracranial sigmoid sinus that produced a troublesome bleeding immediately after the muscular-periosteal flap incision was performed.

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OBJECTIVE: F-18-FDG-avid lymph node (LN) metastasis may preferentially occur along the lymphatic drainage pathway (LDP) from the tumor-bearing lobe in patients with non-small cell lung cancer (NSCLC) on FDG PET/CT. This study evaluated whether the identification of metastatic LNs according to LDP-based visual image interpretation can improve LN staging on FDG PET/CT in these patients. METHODS: FDG PET/CT study was performed in 265 patients with NSCLC. The presence and LN station of metastatic LNs were determined by surgery or the clinical course. In the LDP-based interpretation, FDG-avid LNs, which were located along the preferential LDP from each tumor-bearing lobe and visually more intense in FDG uptake compared with the remaining LNs straying away from the preferential LDP, were diagnosed as metastatic. The result was compared with the quantitative method using a cutoff value of 2.5 for the maximum standardized uptake value. RESULTS: Of the total 1031 mediastinal and hilar LN stations with FDG-avid LNs in 265 patients, 179 stations in 66 patients were metastatic and the remaining 852 were benign. All the metastatic LN stations except for 2 stations showing skip metastasis were located along the main preferential LDP or another preferential LDP via a direct anatomic pathway from each tumor-bearing lung lobe. The specificity, accuracy, and PPV for identifying metastatic LN stations by LDP-based interpretation were 97.9, 95.7 and 89.5 %, respectively, which were significantly greater compared with those of 92.7, 90.8 and 70.3 % by the SUV-based method (P < 0.001). CONCLUSIONS: The present study shows that FDG-avid LN metastasis preferentially occurs along the LDP from the tumor-bearing lobe in NSCLC patients. LDP-based visual image interpretation on FDG PET/CT can improve LN staging in these patients.

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OBJECTIVE: Radical hysterectomy with pelvic lymphadenectomy is the treatment of choice for early-stage cervical cancer. Wertheim's original technique has been often modified, mainly in the extent of parametrectomy. Okabayashi's technique is considered as the most radical variant regarding removal of the ventral parametrium and paracolpal tissues. Surgical outcome concerning recurrence and survival is good, but morbidity is high due to autonomic nerve damage. While the autonomic network has been studied extensively, the lymphatic system is less understood. This study describes the lymphatic drainage pathways of the cervix uteri and specifically the presence of lymphatics in the vesico-uterine ligament (VUL). METHODS: A developmental series of 10 human female fetal pelves was studied. Paraffin embedded blocks were sliced in transverse sections of 8 or 10 µm. Analysis was performed by staining with antibodies against LYVE-1 (lymphatic endothelium), S100 (Schwann cells), alpha-Smooth Muscle Actin (smooth muscle cells) and CD68 (macrophages). The results were three-dimensionally represented. RESULTS: Two major pathways drained the cervix uteri: a supra-ureteral pathway, running in the cardinal ligament superior to the ureter, and a dorsal pathway, running in the utero-sacral ligament towards the rectal pillars. No lymph vessels draining the cervix uteri were detected in the VUL. In the paracolpal parametrium lymph vessels draining the upper vagina fused with those from the bladder. CONCLUSIONS: The VUL does not contain lymphatics from the cervix uteri. Hence, the favorable survival outcomes of the Okabayashi technique cannot be explained by radical removal of lymphatic pathways in the ventrocaudal parametrium.

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Immunological privilege appears to be a product of unique lymphatic drainage systems for the brain and receptor-mediated entry of inflammatory cells through the blood-brain barrier. Most organs of the body have well-defined lymphatic vessels that carry extracellular fluid, antigen presenting cells, lymphocytes, neoplastic cells and even bacteria to regional lymph nodes. The brain has no such conventional lymphatics, but has perivascular pathways that drain interstitial fluid (ISF) from brain parenchyma and cerebrospinal fluid (CSF) from the subarachnoid space to cervical lymph nodes. ISF and solutes drain along narrow, ∼100 nm-thick basement membranes within the walls of cerebral capillaries and arteries to cervical lymph nodes; this pathway does not allow traffic of lymphocytes or antigen presenting cells from brain to lymph nodes. Although CSF drains into blood through arachnoid villi, CSF also drains from the subarachnoid space through channels in the cribriform plate of the ethmoid bone into nasal lymphatics and thence to cervical lymph nodes. This pathway does allow the traffic of lymphocytes and antigen presenting cells from CSF to cervical lymph nodes. Efferent pathways by which lymphocytes enter the brain are regulated by selected integrins on lymphocytes and selective receptors on vascular endothelial cells. Here we review: (1) the structure and function of afferent lymphatic drainage of ISF and CSF, (2) mechanisms involved in the efferent pathways by which lymphocytes enter the brain and (3) the failure of lymphatic drainage of the brain parenchyma with age and the role of such failure in the pathogenesis of Alzheimer's disease.

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