A Novel Blasted and Grooved Low Profile Pedicle Screw Able to Resist High Compression Bending Loads

OBJECTIVE: Polyaxial pedicle screws are a safe, useful adjunct to transpedicular fixation. However, the large screw head size can cause soft tissue irritation, high rod positioning, and facet joint injury. However, the mechanical resistance provided by small and low profile pedicle screws is very limited. We therefore developed a novel, low profile pedicle screw using grooving and blasting treatment that is able to resist a high compression bending load. METHODS: We evaluated the compression bending force to displacement and yield loads for seven different screw head types that differed with regard to their groove intervals and whether or not they had been blasted. RESULTS: The rank order of screw types that had the greatest compression bending force to displacement was as follows: (1) universal polyaxial, (2) low polyaxial with 0.1mm grooves and blasting, (3) low polyaxial with blasting, (4) low polyaxial with 0.15mm grooves and blasting, (5) low polyaxial with 0.05mm grooves and blasting, (6) low polyaxial with 0.05mm grooves, (7) and low polyaxial. Low polyaxial screws with 0.1mm grooves and blasting had the maximum yield load and highest compression bending force to displacement of all seven polyaxial screw head systems evaluated. CONCLUSION: Blasting and grooving treatment of pedicle screw heads resulted in screw heads with a high yield load and compression bending force relative to displacement because of increased friction. Low polyaxial pedicle screws with 0.1 mm grooves treated by blasting have mechanical characteristics similar to those of universal polyaxial pedicle screws.

A Novel Blasted and Grooved Low Profile Pedicle Screw Able to Resist High Compression Bending Loads

OBJECTIVE: Polyaxial pedicle screws are a safe, useful adjunct to transpedicular fixation. However, the large screw head size can cause soft tissue irritation, high rod positioning, and facet joint injury. However, the mechanical resistance provided by small and low profile pedicle screws is very limited. We therefore developed a novel, low profile pedicle screw using grooving and blasting treatment that is able to resist a high compression bending load. METHODS: We evaluated the compression bending force to displacement and yield loads for seven different screw head types that differed with regard to their groove intervals and whether or not they had been blasted. RESULTS: The rank order of screw types that had the greatest compression bending force to displacement was as follows: (1) universal polyaxial, (2) low polyaxial with 0.1mm grooves and blasting, (3) low polyaxial with blasting, (4) low polyaxial with 0.15mm grooves and blasting, (5) low polyaxial with 0.05mm grooves and blasting, (6) low polyaxial with 0.05mm grooves, (7) and low polyaxial. Low polyaxial screws with 0.1mm grooves and blasting had the maximum yield load and highest compression bending force to displacement of all seven polyaxial screw head systems evaluated. CONCLUSION: Blasting and grooving treatment of pedicle screw heads resulted in screw heads with a high yield load and compression bending force relative to displacement because of increased friction. Low polyaxial pedicle screws with 0.1 mm grooves treated by blasting have mechanical characteristics similar to those of universal polyaxial pedicle screws.

Add on Lamivudine to Adefovir Monotherapy for the Treatment of Lamivudine-resistant Chronic Hepatitis B Patients / 대한소화기학회지

BACKGROUND/AIMS: Add on adefovir (ADV) to ongoing lamivudine (LAM) has been recommended as a standard therapy for the treatment of LAM resistance. In the past, switch to ADV monotherapy was suggested as an option for the treatment of LAM resistance, leading to frequent development of ADV resistance. However, ADV monotherapy has been still used in LAM-resistant patients because of low cost in Korea. The aims of this study were to evaluate the virologic response and virologic breakthrough during adding on LAM in LAM-resistant patients receiving ADV monotherapy. METHODS: The study population comprised 99 patients with LAM-resistance. We divided them into 3 groups (Group 1: switch to ADV monotherapy, N=58, Group 2: add on ADV to ongoing LAM, N=25, Group 3: add on LAM to ADV monotherapy, N=16). HBV DNA levels were assessed at baseline and every 3 months during therapy. Serum HBV DNA levels were measured by bDNA assay or the COBAS TaqMantrade mark HBV test. RESULTS: The median treatment duration for group 1, group 2, and group 3 was 42.0, 20.6, and 31.8 (18.7 mon. of ADV+13.1 mon. of LAM) months, respectively. Cumulative rate of virologic breakthrough in group 1 was 5.2%, 19.0%, and 25.9% at 12, 24, and 36 months of treatment, respectively. Virologic breakthrough was not detected in group 2 and group 3 (p=0.016, group 1 vs. group 2 or 3). In group 3, median serum HBV DNA levels were 4.22 log10 copies/mL prior to LAM administration. Median serum HBV DNA changes from baseline (log10 copies/mL) were -0.91, -1.93, -1.87 and -1.74 at week 12, 24, 36 and 48, respectively. CONCLUSIONS: Later add on LAM to ADV monotherapy prevented the development of ADV resistance in patients with LAM resistance effectively, comparable to ADV add on to continuing LAM therapy.

A Case of Endoscopic Enucleation for Gastric Lymphoepithelioma-like Carcinoma / 대한소화기내시경학회지

Lymphoepithelioma-like carcinoma (LELC) is a rare cancer and it makes up about 1~4% of all gastric malignancies. The main histologic feature of LELC is a lymphoid stroma. LELC is rare in that its shape is similar to that of submucosal tumor (SMT). Although SMT can be divided into malignant and benign tumors, using endoscopic ultrasonography (EUS) and EUS-guided fine needle aspiration, there are still many cases that can't be discriminated, and it is especially difficult to obtain specimens due to the small size of SMT. There have been some recent trials to endoscopic remove small SMTs for the purpose of making an exact diagnosis and guiding therapy. We report here a case of gastric LELC that exhibited the features of a submucosal tumor, and this LELC was removed by endoscopic enucleation. We also briefly review the relevant medical literature.

Clinical Characteristics of Gastrointestinal Carcinoid Tumors / 대한소화기내시경학회지

BACKGROUND/AIMS: Various factors have been reported that can predict the clinical course and outcome of patients with gastrointestinal (GI) carcinoid tumors. We analyzed the clinical characteristics of GI carcinoid tumors and the factors associated with metastasis. METHODS: We retrospectively analyzed the clinical manifestations, treatment modalities and prognosis of 83 patients with GI carcinoid tumors. RESULTS: The mean age of the patients was 48 years old. The locations of the carcinoid tumors were rectum (n=60), stomach (n=12), duodenum (n=6), appendix (n=4) and colon (n=1). The most common symptom was non-specific (n=65, 79.5%), and the mean tumor size was 11.2 mm. The main treatment modality was endoscopic resection (n=66, 79.5%). Nine patients showed metastasis, and all of their tumors were larger than 2 cm. Univariate analysis revealed that size, ulceration and invasion of the proper muscle layer were significant factors associated with metastasis. Tumor size (p=0.001) was the only independent factor on multivariate analysis. CONCLUSIONS: The diagnosis of small sized, asymptomatic GI carcinoid tumors has increased and endoscopic treatment was a useful modality. Tumor size was a predictive factor for metastasis.

Diagnostic Noninvasive Tests for Coronary Artery Disease in Chronic Renal Failure Patients / 대한신장학회잡지

BACKGROUND: As ischemic heart disease is the major cause of death in chronic renal failure patients, screening tests are clinically important. Although coronary angiography is considered the gold standard for the diagnosis of coronary artery disease, other noninvasive tests are usually used to avoid this potentially dangerous and costly procedure. METHODS: We retrospectively determined the sensitivity, specificity, and positive and negative predictive values for electrocardiography, echocardiography, cardiac enzyme determination, and Technetium 99m tetrofosmin (TF) single photon emission computed tomography (SPECT) in 61 chronic renal failure patients who underwent coronary angiography. RESULTS: Nineteen patients (31.1%) were undergoing chronic hemodialysis, seven patients (11.4%) were undergoing peritoneal dialysis, and thirty five patients (57.3%) were undergoing conservative treatment. 99mTc SPECT had a sensitivity of 96% and specificity of 19%. Although echocardiography and tronponin-T had a relatively lower sensitivity of 69 % and 56% than 99mTc SPECT, they had a higher specificity of 63% and 63%, respectively. 99mTc SPECT had the highest sensitivity of 88% and echocardiography had the highest specificity of 78% in renal replacement group. 99mTc SPECT had the highest sensitivity of 100% and Troponin T had the highest specificity of 71% in conservative treatment group. CONCLUSION: Noninvasive test for coronary artery disease in patients with chronic renal failure, especially 99mTc SPECT is of limited value because of their low specificity, so echocardiography and troponin T may helpful for diagnosing coronary artery disease.

Changes in serum and dialysate levels of Cancer Antigen 125 (CA125) in continuous ambulatory peritoneal dialysis patients / 대한내과학회지

BACKGROUND: Peritoneal mesothelial cells are the most important intraperitoneal cells quantitatively and have the capability to secret different types of substances. It may therefore be essential to have information on the mesothelial cell mass during peritoneal dialysis. Cancer Antigen 125 (CA125) is a 22KDa glycoprotein which is a clinically useful tumor marker of non-mucinous epithelial ovarian carcinoma. Recently, other cells including pleural and peritoneal mesothelial cell have been proved to express CA125. This study was undertaken to determine whether CA125 can be used as a marker of mesothelial cell mass in clinically stable 39 CAPD patients. METHODS: We checked serum and peritoneal dialysate CA125 level, D/P creatinine and D/Do glucose after 4 hours dwell in 39 stable continuous ambulatory CAPD patients. RESULTS: No statistically significant correlation was seen among the patient's age, sex, serum and dialysate levels of CA125. The dialysate CA125 levels correlated with the duration of CAPD, negatively (r=-0.345, p=0.039) and a significant positive correlation was seen between the duration of CAPD and D/Do glucose at 4 hours (r=0.523, p=0.001). But there were not a correlation between the dialysate CA125 levels and D/P creatinine after 4 hours dwell nor between the dialysate CA125 levels and D/Do glucose after 4 hours dwell. CONCLUSION: Although the duration of CAPD affects CA125 levels in dialysate, no specific alteration in peritoneal membrance transport properties can be detected or predicted by changes in dialysate concentration of CA125. However longitudinal follow-up of changes in concentration of dialysate CA125 may be useful in evaluating mesothelial cell mass in stable CAPD patients.Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.

SIADH Associated with Guillain-Barre Syndrome / 대한신장학회잡지

The most common cause of hyponatremia in hospitalized patients is syndrome of inappropriate antidiuretic hormone secretion (SIADH) characterized by water retention leading to decreased serum sodium concentration and osmolality. Since the report of Schwartz and his co-workers1), this syndrome has been described in various clinical settings. There are some reports on SIADH associated with Guillain-Barre syndrome in the literature2-6). However, to our knowledge, there was only one reported case of SIADH associated with Guillain-Barre syndrome in Korea

Usefulness of Assessing Hemodialysis Adequacy Using the Stop Dialysate Flow (SDF) Method / 대한신장학회잡지

BACKGROUND: K/DOQI guidelines recommend the slow flow method as a standardized method of postdialysis blood sampling for measuring hemodialysis adequacy. However, it is not easy to adopt this method when working in busy renal units where it is often difficult to obtain repeated samples exactly at the specified time. The stop dialysis flow (SDF) method recommended by the Scottish Renal Association since 1998 has the advantage of involving 2 steps only: (1) switch off dialysate flow at the end of hemodialysis without altering the blood pump speed and (2) take a blood sample after 5 minutes from the arterial or venous port. However, there are some limitations to SDF mthod in that it does not allow for tissue rebound after the first 5 minutes postdialysis and cannot be used directly to calculate equilibrated Kt/V (Kt/Veq) using either a 30-minute postdialysis sample. We derived a formula that uses a 5-minute postdialysis BUN sample using the SDF method to estimate the BUN concentration at 30 minutes and investigated if it is useful to assess hemodialysis adequacy using this method. METHODS: A total of 51 patients who had been undergoing hemodialysis in Chonnam National University Hospital and had agreed in joining this study were involved. Patients were randomly selected to 2 groups. Blood samples were obtained immediately before dialysis and at 0, 5, and 30 minutes postdialysis. We calculated the linear relationship between the 5-minute and 30-minute postdialysis samples in group A patients (n=25) and validated this equation using the data from the other group B patients (n= 26). We predicted what the 30-minute BUN concentration would be using the measured value of BUN at 5 minutes and compared directly the value of our estimated 30-minute BUN with the measured 30- minute BUN. RESULTS: There was a tight linear correlation (R2=0.993, p<0.05), between measured 5-minute postdialysis BUN concentrations and measured 30-minute postdialysis BUN concentrations in group A patients. This relationship is described by the linear regression equation: 30-minute BUN concentration=1.05x(5-minute BUN concentraion)+1.04. We used this equation to estimate the 30-minute BUN concentration in group B patients based on the 5-minute postdialysis BUN sample from these patients. And there was a close correlation between estimated and measured 30-minute postdialysis BUN concentration (R2= 0.989, p<0.05). The sensitivity, specificity, positive, and negative predictive values of this equation were high when used to estimate 30-minute urea reduction ratio (URR) greater than 65% (88.9%, 100%, 100 %, and 94.4%, respectively) and 30-minute Kt/Vsp greater than 1.2 (100%, 100%, 100%, 100%, respectively). CONCLUSION: We could estimate 30-minute postdialysis BUN concentration, 30-minute Kt/V, and 30-minute URR exactly using SDF method and linear regression equation derived in this study. The advantage of involving 2 steps only makes SDF method a useful tool in assessing hemodialysis adequacy.