PURPOSE: To evaluate the early clinical results of lumbar microdiscectomy using minimally invasive tubular retractor (METRx-MD system, Medtronic Sofamor Danek, Memphis, TN), and to validate the merits of minimally invasive spinal surgery. MATERIALS AND METHODS: From April, 2003 to April 2004 we retrospectively studied a consecutive series of 45 patients who underwent lumbar microdiscectomy using minimally invasive tubular retractor. In all cases, minimally invasive approach using the tubular retractor were performed with a 2 cm sized paramedian incision. The following data were collected: clinical outcomes, operative time, intraoperative blood loss, need for blood replacement, time needed before ambulation, length of hospital stay, and complications. The clinical outcomes were assessed by the modified MacNab criteria. RESULTS: Minimally invasive tubular microdiscectomy was performed in 45 patients over a 12-month period with an average follow-up of approximately 8 months. The clinical outcomes assessed by MacNab criteria were excellent in 33 patients (73%), good in 10 patients (22%). The average operative time was 63 minutes (range, 35 to 95 minutes). The average blood loss was 62 mL (range, 50 to 110 mL). None of the patients needed blood replacement. With the exception of 2 patients, all patients could walk at the day of surgery. The average hospital stay was 2.3 days. None of the patients had dural tear, wound problem, or other complications. CONCLUSION: Lumbar microdiscectomy using tubular retractor can offer a useful modality for the treatment of lumbar herniated disc with the merits of minimally invasive spinal surgery. Further long-term, randomized, prospective investigations are needed to fully evaluate the impact of this technique.
Follow-Up Studies ; Humans ; Intervertebral Disc Displacement ; Length of Stay ; Operative Time ; Wounds and Injuries

PURPOSE: To realistically map the electric fields of biological tissues using a diffusion tensor magnetic resonance electrical impedance tomography (DT-MREIT) method to estimate tissue response during electrical stimulation. METHODS: Imaging experiments were performed using chunks of bovine muscle. Two silver wire electrodes were positioned inside the muscle tissue for electrical stimulation. Electric pulses were applied with a 100-V amplitude and 100-μs width using a voltage stimulator. During electrical stimulation, we collected DT-MREIT data from a 3T magnetic resonance imaging scanner. We adopted the projected current density method to calculate the electric field. Based on the relation between the water diffusion tensor and the conductivity tensor, we computed the position-dependent scale factor using the measured magnetic flux density data. Then, a final conductivity tensor map was reconstructed using the multiplication of the water diffusion tensor and the scale factor. RESULTS: The current density images from DT-MREIT data represent the internal current flows that exist not only in the electrodes but also in surrounding regions. The reconstructed electric filed map from our anisotropic conductivity tensor with the projected current density shows coverage that is more than 2 times as wide, and higher signals in both the electrodes and surrounding tissues, than the previous isotropic method owing to the consideration of tissue anisotropy. CONCLUSIONS: An electric field map obtained by an anisotropic reconstruction method showed different patterns from the results of the previous isotropic reconstruction method. Since accurate electric field mapping is important to correctly estimate the coverage of the electrical treatment, future studies should include more rigorous validations of the new method through in vivo and in situ experiments.
Anisotropy ; Diffusion Tensor Imaging ; Diffusion* ; Electric Conductivity* ; Electric Impedance ; Electric Stimulation* ; Electrodes ; Magnetic Resonance Imaging ; Methods ; Silver ; Water*

The characterisitic finding of hypertrophic cardiomyopathy is left ventricular hypertrophy without dilated chamber. Echocardiographic studies of patients with pheochromocytoma in the past have revealed both dilated and hypertrophic cardiomyopathies, as well as obstruction of the left ventricular outflow tract. We report this case because we experienced a pheochromocytoma patient who had reversible hypertrophic cardiomyopathy which might be related with circulating catecholamine level.
Cardiomyopathy, Hypertrophic* ; Echocardiography ; Humans ; Hypertrophy, Left Ventricular ; Pheochromocytoma*

To evaluate the cerebral blood flow in feline hydrocephalic brain, this study was designed to measure the regional cerebral blood flow(rCBF;frontal and periventricular area) by the hydrogen clearance method in different stages of the kaolin-induced hydrocephalus and the postshunt status. The results were as follows: 1) A reduction of rCBF was detected in the left periventricular area at two weeks after kaolin injection. A significant reduction of rCBF was revealed in the left periventricular area at two and four weeks after kaolin injection. However, the rCBF of the left frontal cortex was significantly decreased at four weks after kaolin injection. 2) At one week after shunt operation, the significant restroration of rCBF was found in the left frontal cortex and the left periventricular area.
Brain ; Hydrocephalus* ; Hydrogen ; Kaolin

No abstract available.
Chondroma*

PURPOSE: The purpose of this study is to compare the change of joint line and patellar position between posterior crucate ligament-retained and posterior cruciate ligament-sacrificed total knee arthroplasty. MATERIALS AND METHODS: Fifty posterior crucate ligament-retained and fifty posterior cruciate-sacrificed total knee arthroplasties were evaluated to compare the joint line height from tibial tuberosity, patella bone height from joint line, patella articular height from joint line, patella bone height from tibial tuberoisty and patella articular height from tibial tuberosity. The measurements were assessed preoperatively and postoperatively. RESULTS: No difference in joint line height from tibial tuberosity, patellar bone height from joint line, patellar articualr height from joint line, patellar bone height from tibial tuberosity and patellar articular height from tibial tuberosity were found with either design (p>0.05). CONCLUSION: This study demonstrates that the resection of the posterior cruciate ligament can be one of the preferable method to increase the flexion gap without influencing the joint line in Total knee arthroplasty.
Arthroplasty ; Joints* ; Knee Joint ; Knee* ; Patella ; Posterior Cruciate Ligament

PURPOSE: This study was to evaluate results after conversion of fused hip to total hip replacement arthroplasty and to correlate factors that affect the results. MATERIALS AND METHODS: Twenty-five hips in twenty-three patients who underwent THRA for bony ankylosis of hip from January 1983 to July 1996 were reviewed. RESULTS: Of 19 cases who had adjacent joint pain, 13 cases improved clinically. The average Harris Hip Score improved from 74 points preoperatively to 86 points postoperatively, and HSS seemed to have no relationship with the causes and duration of ankylosis or presence of previous operation. Radiologically, three of femoral components that had been inserted without cement were loose. The socket was loose in all 6 cases using PM type prosthesis. Within 19 cases that porous coated hemispheric prosthesis were inserted, the socket was loose in 2 cases. The acetabular socket of PM type showed much higher incidence of aseptic loosening ( p< 0.01 ) . CONCLUSION: THRA in fused hip improved the quality of life by restoring joint motion and relieving pain in adjacent joint affected secondarily to fused hip. However, threaded type cup showed high rate of failure due to lack of biologic fixation.
Acetabulum ; Ankylosis ; Arthralgia ; Arthroplasty ; Arthroplasty, Replacement, Hip* ; Hip* ; Humans ; Incidence ; Joints ; Prostheses and Implants ; Quality of Life

The electrical conductivity is a passive material property primarily determined by concentrations of charge carriers and their mobility. The macroscopic conductivity of a biological tissue at low frequency may exhibit anisotropy related with its structural directionality. When expressed as a tensor and properly quantified, the conductivity tensor can provide diagnostic information of numerous diseases. Imaging conductivity distributions inside the human body requires probing it by externally injecting conduction currents or inducing eddy currents. At low frequency, the Faraday induction is negligible and it has been necessary in most practical cases to inject currents through surface electrodes. Here we report a novel method to reconstruct conductivity tensor images using an MRI scanner without current injection. This electrodeless method of conductivity tensor imaging (CTI) utilizes B1 mapping to recover a high-frequency isotropic conductivity image which is influenced by contents in both extracellular and intracellular spaces. Multi-b diffusion weighted imaging is then utilized to extract the effects of the extracellular space and incorporate its directional structural property. Implementing the novel CTI method in a clinical MRI scanner, we reconstructed in vivo conductivity tensor images of canine brains. Depending on the details of the implementation, it may produce conductivity contrast images for conductivity weighted imaging (CWI). Clinical applications of CTI and CWI may include imaging of tumor, ischemia, inflammation, cirrhosis, and other diseases. CTI can provide patient-specific models for source imaging, transcranial dc stimulation, deep brain stimulation, and electroporation.
Animal Experimentation* ; Animals* ; Anisotropy ; Brain ; Deep Brain Stimulation ; Diffusion ; Electric Conductivity ; Electrodes ; Electroporation ; Extracellular Space ; Fibrosis ; Human Body ; Inflammation ; Intracellular Space ; Ischemia ; Magnetic Resonance Imaging* ; Methods

Purpose: This study examined the effects of the postoperative administration of parathyroid hormone (PTH) on fracture healing in intertrochanteric fractures accompanied by osteoporosis in elderly females. Materials and Methods: Female patients aged 65 years and more who underwent surgery after a diagnosis of intertrochanteric fractures and osteoporosis during the period from July 2013 to December 2017 were included as subjects. The subjects were divided into two groups: PTH-treated group and non-PTH-treated group. The formation time of the first callus, timing of the bridging callus, and time of bony union for both groups were evaluated. Results: In the PTH-treated group, the mean time of the first callus formation, average time of bridging callus, and the average time of bony union were 32, 58, 83 days, respectively, which were significantly shorter than that of the untreated group. Conclusion PTH, a treatment for osteoporosis, promotes callus formation and the healing process. Therefore it will be helpful in intertrochanteric fractures accompanied by osteoporosis in elderly females.

STUDY DESIGN: This is a retrospective case study. PURPOSE: This study was designed to analyze the surgical outcomes of patients who underwent minimally invasive transforaminal lumbar interbody fusion (TLIF) for the treatment of spondylolisthesis and degenerative segmental instability. OVERVIEW OF LITERATURE: If the surgical outcomes of a procedure are evaluated together with multiple indications, it is not clear how the procedure helped each subgroup of patients. For the reason that some indications achieve better outcomes than the others, we performed a subgroup analysis using validated outcome measures to demonstrate the optimal indications and the treatment results of TLIF. METHODS: We conducted subgroup analyses by comparing the prospectively collecting data from the consecutive patients who underwent single-level minimally invasive TLIF for the treatment of the following 3 subgroups of indications: 23 cases of low-grade spondylolytic spondylolisthesis, 24 cases of degenerative spondylolisthesis, and 19 cases of degenerative segmental instability. RESULTS: The average duration of follow up was 36.1 +/- 9.9 months (range, 24 to 63 months). The preoperative pain and disability scores were significantly improved at final postoperative follow-up in all the subgroups (all measurements: p < 0.0001). The 3 subgroups exhibited an equivalent improvement of the pain and disability scores at the final follow-up. The rates of radiographic solid fusion and complications were also similar among the 3 groups. CONCLUSIONS: Our data suggests that minimally invasive TLIF optimally and equivalently alleviates all of the associated symptoms and disabilities from low-grade spondylolisthesis and degenerative segmental instability. Furthermore, these patients seem to have optimal surgical indications for minimally invasive TLIF, while maintaining favorable surgical outcomes.
Follow-Up Studies ; Humans ; Outcome Assessment (Health Care) ; Prospective Studies ; Retrospective Studies ; Spondylolisthesis