2.Biomechanical Motion Characteristics of Lumbar Motion Segments : Effects of Radial Tear of the Annulus Fibrosus.
Jae yong AHN ; Junghwa HONG ; Tae Hong LIM ; Howard S AN
Journal of Korean Society of Spine Surgery 1998;5(2):169-176
STUDY DESIGN: Lumbar disc degeneration and segmental instability of the lumbar spine are causes of low back pain. Disc degeneration causes specific changes of the intervertebral disc, and could affect anatomic variations of end plate and vetebral body. However, the exact relationship between degenerative changes of the intervertebral disc and segmental motion characteristics is not known. It is known that radial tears of the annulus fibrosus initiate or accompany degenerative process of nucleus pulposus and the motion segment. It is hypothesis of this study that the existence of radial tear in the annulus fibrosis affects 3 dimension motion characteristics of motion segment. For the purpose, the degree of intervertebral disc degeneration is newly classified by existence of radial tear. Then, the resulting biomechanical motions are investigated. OBJECTIVES: To investigate effects of disc degeneration by the classification on kinematic motions of the motion segment from human lumbar spine and to suggest a quantified method to determine spinal instability in vivo. MATERIALS AND METHODS: A total of 60 spinal motion segments from human lumbar spine was used for this study. To measure 3 dimensioal motion of the motion segments, Vicon system(Oxford, England) with 3 cameras reflective markers and VAX station was used. 6 kinds of pure moments(flexion, extension, right and left axial rotation, and right and left lateral bending) were applied to the motion segments using dead weight for each loading step. At the end of test(maximum loading), motion segments were frozen for anatomical study. For making clear the degree of the degeneration of the disc, a new classification based on MRI results was used: Grade 1 is a normal young disc without tear; Grade 2 is a normal aging disc without radial tear; Grade 3 is a degenerative disc with radial tear; and Grade 4 is a severely degenerative disc with radial tear and other degeneration such as showing decreased disc height. RESULTS: The upper lumbar specimens with radial tears has increased flexion motions as compared to the normal group. Also, the right and left axial rotation in radial tear group increased as compared to the normal group. However, there were no statistical differences in other motions. For the lower lumbar specimens, there were no significant differences in measured motions in all directions between the normal and radial tear groups CONCLUSIONS: These results suggests that the segmental motions are affected by radial tear in the intervertebral disc. Thus, the radial tear in the annulus fibrosus of lumbar intervertebral disc could cause the instability of lumbar spine. Further research is required to determine the relationship between other structural changes and biomechanical characteristics, and future studies should include in vivo investigations to correlate these findings to patients'symptoms.
Aging
;
Classification
;
Fibrosis
;
Humans
;
Intervertebral Disc
;
Intervertebral Disc Degeneration
;
Low Back Pain
;
Magnetic Resonance Imaging
;
Spine
3.Painful Boney Metastases.
Howard S SMITH ; Intikhab MOHSIN
The Korean Journal of Pain 2013;26(3):223-241
Boney metastasis may lead to terrible suffering from debilitating pain. The most likely malignancies that spread to bone are prostate, breast, and lung. Painful osseous metastases are typically associated with multiple episodes of breakthrough pain which may occur with activities of daily living, weight bearing, lifting, coughing, and sneezing. Almost half of these breakthrough pain episodes are rapid in onset and short in duration and 44% of episodes are unpredictable. Treatment strategies include: analgesic approaches with "triple opioid therapy", bisphosphonates, chemotherapeutic agents, hormonal therapy, interventional and surgical approaches, steroids, radiation (external beam radiation, radiopharmaceuticals), ablative techniques (radiofrequency ablation, cryoablation), and intrathecal analgesics.
Activities of Daily Living
;
Analgesics
;
Breakthrough Pain
;
Breast
;
Cough
;
Diphosphonates
;
Lifting
;
Lung
;
Neoplasm Metastasis
;
Prostate
;
Sneezing
;
Steroids
;
Stress, Psychological
;
Weight-Bearing
4.Effect of Bone Mineral Density and Endplate Thickness on the Compressive Strength in the Cervical Spine.
Hee KWON ; Howard S AN ; Tae Hong LIM ; Chang Hoon JEON
Journal of Korean Society of Spine Surgery 1999;6(3):344-348
STUDY DESIGN: This is a biomechanical study to evaluate the subsidence at the cervical endplate from seven fresh cadavers. The study performed after evaluating a bone mineral density(BMD) and a thickness of the endplate. OBJECTIVES: To evaluate the effect of BMD and endplate thickness on the biomechanical strength in an anterior cervical interbody fusion model. MATERIAL AND METHODS: A total of 7 cervical spines(C3-C7) were obtained from fresh cadavers and dissected through the intervertebral disc to obtain the isolated vertebrae. BMD of each vertebral body was measured using a dual-energy x-ray absorptiometry(DEXA) and thickness of endplates was measured by CT images. Each vertebral body was cut into halves through the horizontal plane and prepared specimens were assigned one of the following 3 groups so that group mean BMDs became similar. In group 1, the endplates were preserved intact. The endplates in group 2 were burred into approximately 1/2 of the intact thickness. In group 3, the endplates were totally removed. Each specimen underwent the destructive compression test by using an Instron material test system(MTS). RESULTS: There was significant linea relationship between BMD and load to failure. The load to failure of group 1 was significantly greater than group 3. CONCLUSION: Preoperative consideration of BMD would be important for patient selection and the choice of a surgical technique. And it may be important to preserve the endplate as much as possible to reduced the incidence of subsidence when performing the cervical interbody fusion.
Bone Density*
;
Cadaver
;
Compressive Strength*
;
Incidence
;
Intervertebral Disc
;
Patient Selection
;
Spine*
5.Left Ventricular Assist Devices (LVADS): History, Clinical Application and Complications
Korean Circulation Journal 2019;49(7):568-585
Congestive heart failure is a major cause of morbidity and mortality as well as a major health care cost in the developed world. Despite the introduction of highly effective heart failure medical therapies and simple devices such as cardiac resynchronization therapy that reduce mortality, improve cardiac function and quality of life, there remains a large number of patients who do not respond to these therapies or whose heart failure progresses despite optimal therapy. For these patients, cardiac transplantation is an option but is limited by donor availability as well as co-morbidities which may limit survival post-transplant. For these patients, left ventricular assist devices (LVADs) offer an alternative that can improve survival as well as exercise tolerance and quality of life. These devices have continued to improve as technology has improved with substantially improved durability of the devices and fewer post-implant complications. Pump thrombosis, stroke, gastrointestinal bleeding and arrhythmias post-implant have become less common with the newest devices, making destination therapy where ventricular assist device are implanted permanently in patients with advanced heart failure, a reality and an appropriate option for many patients. This may offer an opportunity for long term survival in many patients. As the first of the totally implantable devices are introduced and go to clinical trials, LVADs may be introduced that may truly be alternatives to cardiac transplantation in selected patients. Post-implant right ventricular failure remains a significant complication and better ways to identify patients at risk as well as to manage this complication must be developed.
Arrhythmias, Cardiac
;
Cardiac Resynchronization Therapy
;
Exercise Tolerance
;
Health Care Costs
;
Heart Failure
;
Heart Transplantation
;
Heart-Assist Devices
;
Hemorrhage
;
Humans
;
Mortality
;
Quality of Life
;
Stroke
;
Thrombosis
;
Tissue Donors
6.Left Ventricular Assist Devices (LVADS): History, Clinical Application and Complications
Korean Circulation Journal 2019;49(7):568-585
Congestive heart failure is a major cause of morbidity and mortality as well as a major health care cost in the developed world. Despite the introduction of highly effective heart failure medical therapies and simple devices such as cardiac resynchronization therapy that reduce mortality, improve cardiac function and quality of life, there remains a large number of patients who do not respond to these therapies or whose heart failure progresses despite optimal therapy. For these patients, cardiac transplantation is an option but is limited by donor availability as well as co-morbidities which may limit survival post-transplant. For these patients, left ventricular assist devices (LVADs) offer an alternative that can improve survival as well as exercise tolerance and quality of life. These devices have continued to improve as technology has improved with substantially improved durability of the devices and fewer post-implant complications. Pump thrombosis, stroke, gastrointestinal bleeding and arrhythmias post-implant have become less common with the newest devices, making destination therapy where ventricular assist device are implanted permanently in patients with advanced heart failure, a reality and an appropriate option for many patients. This may offer an opportunity for long term survival in many patients. As the first of the totally implantable devices are introduced and go to clinical trials, LVADs may be introduced that may truly be alternatives to cardiac transplantation in selected patients. Post-implant right ventricular failure remains a significant complication and better ways to identify patients at risk as well as to manage this complication must be developed.
7.A Biomechanical Comparison of Intralaminar C7 Screw Constructs with and without Offset Connector Used for C6-7 Cervical Spine Immobilization : A Finite Element Study.
Muhammad QASIM ; Jae Taek HONG ; Raghu N NATARAJAN ; Howard S AN
Journal of Korean Neurosurgical Society 2013;53(6):331-336
OBJECTIVE: The offset connector can allow medial and lateral variability and facilitate intralaminar screw incorporation into the construct. The aim of this study was to compare the biomechanical characteristics of C7 intralaminar screw constructs with and without offset connector using a three dimensional finite element model of a C6-7 cervical spine segment. METHODS: Finite element models representing C7 intralaminar screw constructs with and without the offset connector were developed. Range of motion (ROM) and maximum von Mises stresses in the vertebra for the two techniques were compared under pure moments in flexion, extension, lateral bending and axial rotation. RESULTS: ROM for intralaminar screw construct with offset connector was less than the construct without the offset connector in the three principal directions. The maximum von Misses stress was observed in the C7 vertebra around the pedicle in both constructs. Maximum von Mises stress in the construct without offset connector was found to be 12-30% higher than the corresponding stresses in the construct with offset connector in the three principal directions. CONCLUSION: This study demonstrated that the intralaminar screw fixation with offset connector is better than the construct without offset connector in terms of biomechanical stability. Construct with the offset connector reduces the ROM of C6-7 segment more significantly compared to the construct without the offset connector and causes lower stresses around the C7 pedicle-vertebral body complex.
Biomechanics
;
Immobilization
;
Range of Motion, Articular
;
Spine
8.Unusual Soft Tissue Uptake of F-18 Sodium Fluoride in Three Patients Undergoing F-18 NaF PET/CT Bone Scans for Prostate Cancer
Andrew S HAWKINS ; Brandon A HOWARD
Nuclear Medicine and Molecular Imaging 2017;51(3):274-276
Three males aged 71 to 80 years with known stage IV metastatic prostate cancer underwent F-18 sodium fluoride (NaF) PET/CT to assess osseous metastatic disease burden and stability. In addition to F-18 NaF avid known osseous metastases, each patient also exhibited increased F-18 NaF activity in soft tissues. The first patient exhibited multiple F-18 NaF avid enlarged retroperitoneal and pelvic lymph nodes on consecutive PET/CT scans. The second patient demonstrated an F-18 NaF avid thyroid nodule on consecutive PET/CT scans. The third patient exhibited increased F-18 NaF activity in a hepatic metastasis.
Humans
;
Lymph Nodes
;
Male
;
Neoplasm Metastasis
;
Positron-Emission Tomography and Computed Tomography
;
Prostate
;
Prostatic Neoplasms
;
Sodium Fluoride
;
Sodium
;
Thyroid Nodule
9.Endometrial carcinoma in vitro chemosensitivity testing of single and combination chemotherapy regimens using the novel microculture kinetic apoptosis assay: implications for endometrial cancer treatment.
Karen S BALLARD ; Howard D HOMESLEY ; Charles HODSON ; Cary A PRESANT ; James RUTLEDGE ; Allan HALLQUIST ; Mathieu PERREE
Journal of Gynecologic Oncology 2010;21(1):45-49
OBJECTIVE: The in vitro microculture kinetic (MiCK) apoptosis assay has been used to predict single or combination chemotherapy response in leukemia patients. This feasibility study addressed MiCK in endometrial cancer specimens. METHODS: Endometrial cancer specimens from total abdominal hysterectomies were processed at a central laboratory. Single cell suspensions of viable endometrial cancer cells were plated in individual wells. Single and combination regimens were tested: combinations of doxorubicin, cisplatin, and paclitaxel and carboplatin and paclitaxel (Gynecologic Oncology Group [GOG] 209 endometrial cancer phase III trial arms) as well as single agent testing with paclitaxel, carboplatin, doxorubicin, cisplatin, ifosfamide, and vincristine (active agents in GOG trials). Apoptosis was measured continuously over 48 hours. RESULTS: Fifteen of nineteen patients had successful assays. The highest mean chemo sensitivity was noted in the combination of cisplatin, doxorubicin, and paclitaxel with lower mean chemosensitivity for carboplatin and paclitaxel. Combination chemotherapy had higher chemosensitivity than single drug chemotherapy. However, in 25% of patients a single drug had higher chemosensitivity than combination chemotherapy. As single agents, ifosfamide, cisplatin, and paclitaxel had the highest kinetic unit values. CONCLUSION: Using a panel of agents simulating clinical dose regimens, the MiCK assay was feasible in evaluating in vitro chemosensitivity of endometrial cancer. MiCK assay results correlated with GOG clinical trial results. However, 25% of patients might be best treated with single agent chemotherapy selected by MiCK. Ifosfamide, cisplatin, and paclitaxel appear to have high activity as single agents. MiCK may be useful in future new drug testing and individualizing endometrial cancer patient's chemotherapy management.
Apoptosis
;
Carboplatin
;
Cisplatin
;
Doxorubicin
;
Drug Therapy, Combination
;
Endometrial Neoplasms
;
Feasibility Studies
;
Female
;
Humans
;
Hysterectomy
;
Ifosfamide
;
Leukemia
;
Paclitaxel
;
Suspensions
;
Vincristine
10.Neuropathic Pain Components in Patients with Lumbar Spinal Stenosis.
Si Young PARK ; Howard S AN ; Seong Hwan MOON ; Hwan Mo LEE ; Seung Woo SUH ; Ding CHEN ; Jin Ho JEON
Yonsei Medical Journal 2015;56(4):1044-1050
PURPOSE: To determine the prevalence and characteristics of neuropathic pain (NP) in patients with lumbar spinal stenosis (LSS) according to subgroup analysis of symptoms. MATERIALS AND METHODS: We prospectively enrolled subjects with LSS (n=86) who were scheduled to undergo spinal surgery. The patients were divided into two groups according to a chief complaint of radicular pain or neurogenic claudication. We measured patient's pain score using the visual analog scale (VAS), Oswestry Disability Index (ODI) and Leads Assessment of Neuropathic Symptoms and Signs (LANSS). According to LANSS value, the prevalence of NP component pain in patients with LSS was assessed. Statistical analysis was performed to find the relationship between LANSS scores and the other scores. RESULTS: From our sample of 86 patients, 31 (36.0%) had a NP component, with 24 (63.4%) in the radicular pain group having NP. However, only seven patients (15.6%) in the neurogenic claudication group had NP. The LANSS pain score was not significantly correlated with VAS scores for back pain, but did correlate with VAS scores for leg pain (R=0.73, p<0.001) and with ODI back pain scores (R=0.54, p<0.01). CONCLUSION: One-third of the patients with LSS had a NP component. The presence of radicular pain correlated strongly with NP. The severity of leg pain and ODI score were also closely related to a NP component. This data may prove useful to understanding the pain characteristics of LSS and in better designing clinical trials for NP treatment in patients with LSS.
Adult
;
Aged
;
Back Pain
;
Decompression, Surgical
;
Disability Evaluation
;
Female
;
Humans
;
*Lumbar Vertebrae/surgery
;
Male
;
Middle Aged
;
Neuralgia/*complications/epidemiology
;
Outcome Assessment (Health Care)
;
Pain Measurement/*methods
;
Prevalence
;
Prospective Studies
;
Republic of Korea/epidemiology
;
Severity of Illness Index
;
Spinal Stenosis/epidemiology/*surgery
;
Surveys and Questionnaires
;
Treatment Outcome