Objective: Despite the increasingly widespread adoption of unilateral biportal endoscopic (UBE) decompressive laminectomy for lumbar spinal stenosis, the learning curve for surgeons new to endoscopic techniques remains a significant barrier. This study aimed to quantify this learning curve and identify strategies to expedite proficiency, focusing on reducing operative times and complications. Methods: The cumulative summation test was used to evaluate the learning curves for both the operative time and the degree of intraoperative dural tear occurrence. Moreover, clinical outcomes and postoperative complications were compared between the cranial and caudal approaches, depending on the direction of ligamentum flavum removal. Results: In total, 54 patients were included, with 22 in the cranial group and 32 in the caudal group. The operative time was notably shorter in the caudal group (cranial group, 110.86±32.63 minutes; caudal group, 79.56±24.21 minutes; p<0.01), and the complication rate was considerably lower (cranial group, 40%; caudal group, 15%; p=0.04). Twenty-six patients and 29 patients were needed to overcome the learning curves for operative time and intraoperative dural tear occurrence, respectively. Conclusion Although UBE surgery has a short learning curve, a considerable number of cases (26 and 29, respectively) were needed to achieve competency in terms of operative time and intraoperative dural tear occurrence. We highlight the caudal-to-cranial direction of ligamentum flavum dissection and removal as a way to decrease the number of dural tears and shorten the operative time.

Tumor-to-tumor metastasis (TTM) is defined as the hematogenous metastasis within a primary host tumor from a donor neoplasm. Since there is insufficient evidence regarding the pathophysiology, clinical course, and management of TTM, there are no precise guidelines for its management. A 73-yearold female patient diagnosed with breast cancer was found to have convexity meningioma. Since the size of tumor and peritumoral brain edema increased during follow-up period, the meningioma was treated with surgical resection. Postoperatively, histopathologic examination confirmed metastasis of invasive ductal carcinoma within a secretory meningioma. The final diagnosis was TTM of breast cancer in meningioma. Here, we report a rare case of intra-meningioma metastasis and a review of literature to provide a better understanding of this rare phenomenon.

PURPOSE: To evaluate the incidence and clinical features of age-related macular degeneration (AMD) in Korea. METHODS: Web-based (www.armd-nova.or.kr) registration was conducted for AMD patients aged 50 or more who were newly diagnosed by retinal specialists in Korea from August 20, 2005 to August 20, 2006. Patient data including ophthalmologic examination, fundus photography, fluorescein angiogram and/or indocyanin green angiogram (ICG), past medical history, behavioral habit, combined systemic diseases were up-loaded. RESULTS: Among finally enrolled 1,141 newly diagnosed AMD patients, 690 patients (60.5%) were male and 451 patients (39.5%) were female. The average age of AMD patients was 69.7+/-8.0. Early AMD was observed in 190 patients and 951 patients had late AMD. Classic choroidal neovascular membrane (CNVM) was observed in 18.6% of exudative AMD patients and 63.4 % had occult CNVM. Subfoveal CNVM was observed in 80.4% of the patients with CNVM. Among the 580 exudative AMD eyes that performed indocyanin green angiography (ICG), 184 eyes (31.7%) had polypoidal choroidal vasculopathy (PCV) and 36 eyes (6.2%) showed retinal angiomatous proliferation (RAP). Age, male gender, smoking, diabetes and hypertension significantly increased the risk of the AMD among Koreans. CONCLUSIONS: Because of the low rate of participation by retinal specialists, definite incidence of AMD was not obtainable. However, the estimated 1-year AMD incidence in the Pusan area of Korea is at least 0.4%. In contrast to Western people, 31.7% of exudative AMD cases were revealed to be PCV and 6.2% were revealed to be RAP. This discrepancy between ethnic groups should be considered in the diagnosis and treatment modality selection of Korean AMD patients.
Aged ; Angiography ; Choroid ; Ethnic Groups ; Eye ; Female ; Fluorescein ; Humans ; Hypertension ; Incidence ; Korea ; Macular Degeneration ; Male ; Membranes ; Photography ; Retinaldehyde ; Smoke ; Smoking ; Specialization