Kwang-Il Lee

The risk assessment of a fall in patients with lumbar spinal stenosis

Study Design. A prospective case control study. Objectives. To investigate the risk of a fall by using functional mobility tests in patients with lumbar spinal stenosis (LSS) via a comparison with patients with knee osteoarthritis (KOA). Summary of Background Data. LSS is a degenerative arthritic disease in the spine that results in decreasing function, impaired balance, and gait deficit, with increased levels of leg and back pain. This physical impairment may result in an increased risk of fall later in the disease process, as shown in KOA. However, there has been no study regarding the association between the risk of a fall and LSS. Methods. The study was an age- and weight-matched case control study consisting of two groups: one group consisting of 40 patients with LSS who were scheduled to undergo spine surgery (LSS group) and the other group consisting of 40 patients with advanced osteoarthritis in both knees, scheduled to undergo TKA on both knees (KOA group). For both groups, four functional mobility tests, such as a Six-Meter-Walk Test (SMT), Sit-to-Stand test (STS), Alternative-Step Test (AST), and Timed Up and Go Test (TUGT), were performed. Results. There was no difference in demographic data between both groups except for body mass index. For the SMT and STS, the patients in the LSS group spent significantly more time performing these tests than the patients in the KOA. For the AST, however, patients in the KOA group presented a statistically worse performance in functional mobility, compared with the LSS group. The mean TUGT time was not statistically different between the two groups. Conclusions. The current study highlights that patients with symptomatic LSS have a risk of a fall comparable with the patients who had degenerative KOA based on the results of functional mobility tests (SMT, STS, AST, and TUGT).

Percutaneous cryoablation of small hepatocellular carcinomas using a 17-gauge ultrathin probe

AIM To evaluate the feasibility and safety of percutaneous cryoablation (PCA) of small hepatocellular carcinomas (HCCs) using a 17 G ultrathin cryoprobe. MATERIALS AND METHODS Twenty patients (male:female ratio14:6) with 20 HCCs, who were not surgical candidates, underwent ultrasound (US)-guided PCA for treatment of HCCs. Single HCCs less than 3cm in diameter were included in this study. Ablation was performed using a 17 G cryoprobe. The effectiveness was determined by the changes in alpha-foetoprotein level and degree of tumour necrosis on follow-up computed tomography (CT); complete response (100% necrosis), partial response (100%>necrosis≥30%), stable disease (any cases not qualifying for either partial response or progressive disease) and progressive disease (increase of at least 20% in diameter of viable tumour). Haemoglobin, white blood cell count (WBC), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and total bilirubin were compared before and after the procedure, and the technical feasibility, complications, clinical outcomes and survival of each patient were also evaluated. RESULTS All procedures were technically successful. Each patient complained of negligible pain and there was no other procedure-related complication or mortality. The mean level of alpha-foetoprotein declined significantly from 53.2 to 20.4ng/ml 1 month after the procedure (p<0.05). At 1-month follow-up CT, there were 13 complete responses, four partial responses, three patients with stable disease, and no patients had progressive disease. Six of seven lesions that did not present with a complete response underwent further treatment. On long-term follow up (6-30 months; mean 20.7), a local recurrence was seen in one of 13 lesions (8%) with complete response revealed. Laboratory findings showed no significant changes except for the transient increase of SGOT and SGPT. CONCLUSION US-guided PCA using a 17 G cryoprobe was feasible and safe for the treatment of HCC smaller than 3cm.

Effective healing of chronic rotator cuff injury using recombinant bone morphogenetic protein-2 coated dermal patch in vivo

Biologic augmentation for rotator cuff repair is a challenging treatment in patients with chronic large, massive, and irreparable rotator cuff injuries. Particularly, the use of an extracellular matrix (ECM) patch such as dermal tissue offered improved biomechanical properties in previous studies. Cytokines induce cell chemotaxis, proliferation, matrix synthesis, and cell differentiation. Moreover, osteoinductive growth factors such as bone morphogenetic protein-2 (BMP-2) affect the formation of new bone and fibrocartilage in lesions. However, the effects of using a dermal patch in combination with BMP-2 have not been evaluated to date, although many researchers have recognized the importance thereof. In this study, rhBMP-2-coated dermal patch (1 cm × 2 cm) isolated from human cadaveric donor was inserted in a rabbit model of chronic rotator cuff injury for in vivo evaluation. Bone mineral density and biomechanical strength were tested and histological and histomorphometric analyses were performed. The results showed that insertion of an rhBMP-2-coated acellular dermal patch not only significantly ameliorated new bone formation, it also improved biomechanical properties such as ultimate tensile strength. Thus, the use of this combination may improve the chronic rotator cuff injury-healing rate and clinical outcomes after rotator cuff repair.

Herniated intervertebral disk induces hypertrophy and ossification of ligamentum flavum.

Study Design: In vitro experiment using degenerated human ligamentum flavum (LF) and herniated intervertebral disk (IVD). Objectives: To investigate the role and effect of degenerated and herniated IVDs on LF hypertrophy and ossification. Summary of Background Data: Spinal stenosis is caused, in part, by hypertrophy and ossification of the LF, which are induced by aging and degenerative process. It is well known that degenerated IVDs spontaneously produce inflammatory cytokines. Therefore, we hypothesized that degenerated IVD may affect adjacent LF through secreted inflammatory cytokines. Methods: LF and herniated lumbar IVD tissues were obtained during surgical spinal procedures. LF fibroblasts were isolated by enzymatic digestion of LF tissue. LF cell cultures were treated with disk supernatant from herniated IVDs. Secreted cytokines from IVD tissue culture were detected by enzyme-linked immunosorbent assay. After analysis of cytotoxicity, DNA synthesis was measured. Reverse transcription-polymerase chain reaction for mRNA expressions of types I, II, III, V, and XI collagen and osteocalcin, and histochemical stains were performed. Results: Supernatant from tissue culture of herniated IVD showed increased production of interleukin-1&agr;, interleukin-6, tumor necrosis factor-&agr;, prostaglandin E2, and nitric oxide compared with disk tissue culture from traumatic condition. There was no cytotoxicity in LF cells treated with disk supernatant from herniated IVDs. There was significant increase in DNA synthesis, upregulation in mRNA expression of types III, XI collagen and osteocalcin, whereas variable expression pattern of type I and V, and strong positive stains for Von Kossa and alkaline phosphatase in LF cultures with disk supernatant. Conclusions: Degenerated and herniated IVDs provide an important pathomechanism in hypertrophy and ossification of the LF through inflammatory cytokines.

Radiographic and functional outcome after surgical management of severe scoliosis in skeletally immature patients with muscular dystrophy.

Objective: Most patients with muscular dystrophy (MD) develop progressive scoliosis after losing ambulatory status, but some cases develop severe scoliosis at a skeletally immature age before losing ambulatory status. Only a few studies have been conducted in skeletally immature patients with severe scoliosis. The purpose of this study was to assess the functional and cosmetic outcome in skeletally immature patients with severe scoliosis. Methods: Preoperative, immediate postoperative, and final follow-up radiographs were analyzed in 10 consecutive skeletally immature patients with respect to the Cobb angle degree and the pelvic obliquity angle correction, how long the correction was maintained, and the development of the crankshaft phenomenon. In the functional assessment, the ability to sit balanced, according to the Mulcahy method, and the ability to use hands, according to the Rhyu method, were evaluated. Furthermore, the degree of subjective satisfaction was evaluated in these patients. Results: The average age of the patients was 10.4 years, and the average follow-up period was 33 months with minimum 2 years’ follow-up. All 10 patients survived and were available at the follow-up. The mean Cobb and pelvic obliquity angles were 80° and 17° at the time of the surgery, 31° and 3.7° immediately after the surgery, and 35° and 4.7° at the time of the final follow-up, respectively. The initial mean Cobb angle correction averaged 61%, with 78% of pelvic obliquity corrected. These corrections were maintained over time in most cases. At the time of the surgery, the mean volume of blood loss was 1111 mL, with an average operation time of 411 minutes. There were no major complications. At the time of the last follow-up, no patient showed development of the crankshaft phenomenon. The average score for the ability to sit balanced improved from 4.4 to 6.6 according to the Mulcahy evaluation method. The scores for hand use were 2.2-2.7. However, the forced vital capacity of the lungs decreased from a preoperative 48% to 46.1%. Conclusions: These results indicate that even in very young MD patients with severe scoliosis, acceptable curve correction can be achieved and maintained with surgery. The improved pelvic obliquity and scoliosis angle stabilized the spine, freeing the upper extremities and allowing productive activities characteristic of childhood.

Biliary intervention for cholangiocarcinoma

Although the prognosis of patients with cholangiocarcinoma after surgical resection is variable and depends on growth characteristics and stages, complete surgical resection offers the best possibility of a cure [1–3]. However, about 56% to 81% of patients have unresectable cholangiocarcinoma because they have an advanced stage tumor or are in an inoperable condition due to bile duct obstruction [4–6]. Therefore, palliative treatments for resolving jaundice are essential in these patients to improve survival length and quality. In this article, we describe percutaneous radiologic interventions for the palliative treatment of cholangiocarcinoma.

Mechanical properties of decellularized tendon cultured by cyclic straining bioreactor

Decellularized tissues have been successfully used in tissue engineering and regenerative medicine for the purpose of removing antigens present in the cellular components. However, this decellularization technique uses ionic solutions or chemical treatments such as enzyme treatments that might damage the biophysical properties or reduce the physical strength of tissue. This study aimed to improve the strength of decellularized tissues. We designed a tissue bioreactor that can repeatedly deliver physical stimulation, such as tensile and torsional deformation, to the upper and lower parts of a tissue. To decellularized porcine Tibialis tendons, we used an enzymatic solution to remove the primary cells, and then applied ultrasonic cleansing using a combination of ionic solution and distilled water to destroy residual cells by differing from the osmotic pressure between the inside and outside of the cell membrane. The total DNA content of decellularized tissue was decreased by 77% compared with that of the original tissue and the ultimate tensile strength of the decellularized tissue was 20% lower than that of the normal tissue. Decellularized tissues were then cultivated in the tissue bioreactor with repeated physical stimulation of 110% tension, 90° torsion, and frequency of once per a second, and the ultimate tensile strength was found to be greater than that of the normal ligament at 7 day culture. This study showed that decellularization using enzyme and mechanical treatment is safe and use of a tissue bioreactor can increase the physical strength of tendons, making this a potential mechanism to reconstruct human ligaments.

Tendon–bone interface healing using an injectable rhBMP‐2‐containing collagen gel in a rabbit extra‐articular bone tunnel model

This study examines the hypothesis that injectable collagen gel can be an effective carrier for recombinant human bone morphogenetic protein‐2 (rhBMP‐2)’s localization to the healing tendon–bone interface. In 36 mature New Zealand White rabbits, the upper long digital extensor tendon was cut and inserted into the proximal tibial bone tunnel. Then a rhBMP‐2‐containing collagen gel was injected into the tendon–bone tunnel interface, using a syringe. Histological and biomechanical assessments of the tendon–bone interface were conducted at 3 and 6 weeks after implantation. In vitro testing showed that the semi‐viscous collagen gel at room temperature was transformed into a firm gel state at 37°C. The rhBMP‐2 release profile showed that rhBMP‐2 was released from the collagen gel for more than 28 days. In vivo testing showed that fibrocartilage and new bone are formed at the interface at 6 weeks after injection of rhBMP‐2. On radiography, spotty calcification appeared and enthesis‐like tissue was produced successfully in the tendon at 6 weeks after injection of rhBMP‐2. Use of the viscous collagen gel and rhBMP‐2 mixture increased the fusion rate between the bone tunnel and tissue graft. This study demonstrates that viscous collagen gel can be an effective carrier for rhBMP‐2 delivery into surgical sites, and that the injectable rhBMP‐2‐containing collagen gel may be applied for the enhancement of tendon–bone interface healing in the future. Copyright

Inactivation of enveloped and non‐enveloped viruses in the process of chemical treatment and gamma irradiation of bovine‐derived grafting materials

Lee K‐I, Lee J‐S, Jung H‐H, Lee H‐Y, Moon S‐H, Kang K‐T, Shim Y‐B, Jang J‐W. Inactivation of enveloped and non‐enveloped viruses in the process of chemical treatment and gamma irradiation of bovine‐derived grafting materials. Xenotransplantation 2012; 19: 365–369.

Standardization for Smart Clothing Technology

Smart clothing is the next generation of apparel. It is a combination of new fabric technology and digital technology, which means that the clothing is made with new signal-transfer fabric technology installed with digital devices. Since this smart clothing is still under development, many problems have occurred due to the absence of the standardization of technology. Therefore, the efficiency of technology development can be strengthened through industrial standardization. This study consists of three phases. The first phase is selecting standardization factors to propose a standardization road map. The second phase is to research and collect related test evaluation methods of smart clothing. For this, we selected two categories, which are clothing and electricity/electron properties. The third phase is establishing a standardization road map for smart clothing. In this study, test evaluations have not yet been conducted and proved. However, this study shows how to approach standardization. We expect that it will be valuable for developing smart clothing technology and standardization in the future.