Dong Won Kim

Comparison of Outcomes of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Microdiscectomy for Young Adults: A Retrospective Matched Cohort Study

OBJECTIVEnThere have been only a few studies on surgical treatment of lumbar disc herniation (LDH) in young adults. In addition, previous studies do not provide detailed information on the surgical outcomes for young adults with LDH. The purpose of this study was to compare the outcome of transforaminal percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy for active, young adults (age 20-25 years).nnnMETHODSnWe performed retrospective chart and radiography. The patients were divided into 2 groups according to the surgical methods. Group A included the patients who underwent transforaminal PELD, and Group B included the patients who underwent open lumbar microdiscectomy for LDH at L4/5. After we matched for several factors, 32 young patients in group A and 34 young patients in group B were analyzed. We compared the outcomes between the 2 groups in terms of clinical, radiologic, perioperative outcomes, and surgery-related complications.nnnRESULTSnThe clinical results for leg pain and radiologic results for decompression were the same in both groups. Most of complications in the PELD group occurred in the early phase. The recurrence rate and operation failure rate was no difference between the groups. The PELD brought significant advantages in the following areas: back pain, operation time, blood loss, hospital stay, and return-to-work.nnnCONCLUSIONSnAlthough a learning curve is needed in order to become familiar with PELD, PELD seemed to be a good choice for disc herniation in the lumbar spine for active, young adults.

Triple rule-out acute chest pain evaluation using a 320-row-detector volume CT: a comparison of the wide-volume and helical modes

The purpose of this study was to investigate the image quality and radiation dose of triple rule-out computed tomography (TROCT) using a 320-row-detector volume CT system to compare the wide-volume and helical modes of this CT system. Sixty-four patients with noncritical chest pain were allocated to one of 2 groups according to the type of CT examination mode used. Group 1 patients were examined using the wide-volume (non-spiral) mode and group 2 patients were examined using the 160-detector row helical mode, with the same contrast injection protocol in both methods [biphasic injection protocol; injection rate of 4xa0ml/s, median volume, 70xa0ml (range 65–100xa0ml)]. Attenuations of the pulmonary trunk, ascending aorta, and coronary arteries were measured in Hounsfield units; a subjective overall patient-based image quality score of 1–3 was awarded to each study. Effective doses, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Average effective dose was significantly lower in group 1 than group 2 (9.7xa0±xa05.1 vs. 16xa0±xa05.9xa0mSv, Pxa0<xa00.001). The mean attenuation of the main pulmonary trunk was significantly higher in group 1 than group 2 (Pxa0=xa00.04) and mean attenuations in other vessels were not significant different. SNR and CNR were not significantly different between the groups. The proportion of diagnostic image qualities for chest CT angiography (CTA) was similar between the groups (93.5 vs. 93.9xa0%). In coronary CTA, group 1 showed a higher proportion of diagnostic image qualities than group 2 (100 vs. 87.9xa0%). The use of wide-volume mode of 320-detector CT reduces the overall effective radiation dose and results in similar attenuation and image quality for TROCT as compared with the helical mode.

The Fate of Adjacent Segments After Anterior Cervical Discectomy and Fusion: The Influence of an Anterior Plate System

OBJECTIVEnThe purpose of this study was to compare anterior cervical discectomy and fusion with cage alone (ACDF-CA) and anterior cervical discectomy and fusion with cage and plate (ACDF-CP) with regard to adjacent segment degeneration (ASD) diagnosed by the use of CT and MRI with retrospective matched cohort design.nnnMETHODSnThis study enrolled 68 patients who underwent single-level ACDF who were diagnosed with cervical degenerative disc disease and were followed up for at least 2 years with plain radiographs, computed tomography, and magnetic resonance imaging. The patients were divided into 2 groups according to the operation method: ACDF-CA (33 patients) and ACDF-CP (35 patients).nnnRESULTSnASD occurred in 4 of 33 patients who underwent ACDF-CA and 9 of 35 patients who underwent ACDF-CP as determined by computed tomography and magnetic resonance imaging. The upper segment range of motion and lower segment range of motion increased in both groups postoperatively. The increase was greater in the ACDF-CP group without statistical significance. The upper segment disc height and lower segment disc height gradually decreased in both groups over time. The decrease was significantly greater in the ACDF-CP group at each follow-up visit. Pseudarthrosis and cage subsidence was observed more in the ACDF-CA group. The pain intensity for the neck in the ACDF-CA group was increased 12 and 24 months postoperatively.nnnCONCLUSIONSnThe anterior plate system in ACDF tends to increase adjacent segmental motion and decrease adjacent segmental disc height. In addition, irrespective of clinical symptoms, ACDF-CP has a greater tendency to result in ASD than ACDF-CA after 24 months after surgery.

Measurement of arterial transit time and renal blood flow using pseudocontinuous ASL MRI with multiple post-labeling delays: Feasibility, reproducibility, and variation.

To evaluate the feasibility, reproducibility, and variation of renal perfusion and arterial transit time (ATT) using pseudocontinuous arterial spin labeling magnetic resonance imaging (PCASL MRI) in healthy volunteers.

Learning Curve of Percutaneous Endoscopic Lumbar Discectomy Based on the Period (Early vs. Late) and Technique (in-and-out vs. in-and-out-and-in): A Retrospective Comparative Study

Objective To report the learning curve of percutaneous endoscopic lumbar discectomy (PELD) for a surgeon who had not been previously exposed to this procedure based on the period and detailed technique with a retrospective matched comparative design. Methods Of 213 patients with lumbar disc herniation encountered during the reference period, 35 patients who were followed up for 1 year after PELD were enrolled in this study. The patients were categorized by the period and technique of operation : group A, the first 15 cases, who underwent by the in-and-out technique; group B, the next 20 cases, who underwent by the in-and-out-and-in technique. The operation time, failure rate, blood loss, complication rate, re-herniation rate, the Visual Analogue Scale (VAS) for back and leg were checked. The alteration of dural sac cross-sectional area (DSCSA) between the preoperative and the postoperative MRI was checked. Results Operative time was rapidly reduced in the early phase, and then tapered to a steady state for the 35 cases receiving the PELD. After surgery, VAS scores for the back and leg were decreased significantly in both groups. Complications occurred in 2 patients in group A and 2 patients in group B. Between the two groups, there were significant differences in operative time, improvement of leg VAS, and expansion of DSCSA. Conclusion PELD learning curve seems to be acceptable with sufficient preparation. However, because of their high tendency to delayed operation time, operation failure, and re-herniation, caution should be exercised at the early phase of the procedure.

The Clinical Significance of Lumbosacral Transitional Vertebrae on the Surgical Outcomes of Lumbar Discectomy: A Retrospective Cohort Study of Young Adults.

OBJECTIVEnTo evaluate whether the presence of lumbosacral transitional vertebrae (LSTV) affects the clinical outcomes of microdiscectomy (MD) in young adults with lumbar disc herniation.nnnMETHODSnWe retrospectively included 398 patients who were followed-up for at least 2 years after MD for lumbar disc herniation at L4/5 (disc above the LSTV). The patients were divided into 2 groups. Group A was made up of 31 patients in whom LSTV was detected. Group B, in contrast, was made up of 35 patients in whom LSTV was not detected. The LSTV were classified using plain radiographs and three-dimensional computed tomography by Castellvi etxa0al. The primary outcome measure was pain intensity at each follow-up visit assessed with visual analog scale for back and leg. Secondary outcome measures included the Oswestry Disability Index, a 12-item short-form health survey for quality of life, complications, and recurrence rate.nnnRESULTSnAfter surgery, the visual analog scale scores for the back and leg decreased significantly in both groups. However, the back pain intensity in group A worsened at 12 and 24 months postoperatively. The Oswestry Disability Index scores and 12-item short-form health survey (both mental and physical) worsened at 12 and 24 months postoperatively in group A. Two cases of reherniation (6.5xa0%) were observed in group A, who required reoperation.nnnCONCLUSIONSnLSTV can limit a patients clinical improvement after MD with regard to pain intensity and recurrence. Caution must be taken when a patient is scheduled to undergo surgery.

Radiologic Findings and Risk Factors of Adjacent Segment Degeneration after Anterior Cervical Discectomy and Fusion : A Retrospective Matched Cohort Study with 3-Year Follow-Up Using MRI

Objective The purpose of this study was to figure out the radiologic findings and risk factors related to adjacent segment degeneration (ASD) after anterior cervical discectomy and fusion (ACDF) using 3-year follow-up radiography, computed tomography (CT), and magnetic resonance image (MRI). Methods A retrospective matched comparative study was performed for 64 patients who underwent single-level ACDF with a cage and plate. Radiologic parameters, including upper segment range of motion (USROM), lower segment range of motion (LSROM), upper segment disc height (UDH), and lower segment disc height (LDH), clinical outcomes assessed with neck and arm visual analogue scale (VAS), and risk factors were analyzed. Results Patients were categorized into the ASD (32 patients) and non-ASD (32 patients) group. The decrease of UDH was significantly greater in the ASD group at each follow-up visit. At 36 months postoperatively, the difference for USROM value from the preoperative one significantly increased in the ASD group than non-ASD group. Preoperative other segment degeneration was significantly associated with the increased incidence of ASD at 36 months. However, pain intensity for the neck and arm was not significantly different between groups at any post-operative follow-up visit. Conclusion The main factor affecting ASD is preoperative other segment degeneration out of the adjacent segment. In addition, patients over the age of 50 are at higher risk of developing ASD. Although there was definite radiologic degeneration in the ASD group, no significant difference was observed between the ASD and non-ASD groups in terms of the incidence of symptomatic disease.

CT-based assessment of renal function impairment in patients with acute unilateral ureteral obstruction by urinary stones.

PurposeThe purpose of our study was to evaluate computed tomography (CT) imaging factors related to renal function impairment in patients with acute unilateral ureteral obstruction by urinary stones.Materials and MethodsThe study included 94 patients who had acute unilateral ureteral obstruction due to a urinary stone and a normal contralateral kidney. We retrospectively investigated the serum creatinine (SCr) levels immediately prior to CT examination and at least 1xa0week after treatment. CT examinations were performed using a CT urography protocol, including pre- and post-contrast images. The 67 patients with a SCr change of less than 0.3xa0mg/dL constituted group A. The other 27 patients with a SCr decrease of more than 0.3xa0mg/dL constituted group B. To evaluate factors related to renal function impairment, differences in CT imaging factors between the two groups, including the cortical and medullary density, renal and pelvic anteroposterior diameter, and perinephric fluid, were statistically analyzed.ResultsThe SCr immediately prior to CT examination significantly differed between the two groups. The follow-up SCr after resolution did not significantly differ between the two groups. The difference in the mean cortical and medullary HU on the nephrographic phase between the obstructed kidney and normal kidney was higher in group B than in group A (27.1xa0±xa023.1 and 69.4xa0±xa059.1 vs. 5.7xa0±xa08.8 and 31.8xa0±xa034.8; pxa0<xa00.001 and pxa0=xa00.004, respectively). The cut-off point for the difference in the mean cortical HU on the nephrographic phase between the obstructed kidney and normal kidney for renal function impairment was 15 HU, as determined by a receiver operating characteristic curve analysis.ConclusionsPatients with significantly impaired renal function due to an acute unilateral ureteral obstruction may show a decreased nephrogram of the affected kidney and a significant difference in the HU on the nephrographic phase between the obstructed and normal kidney.

Noninvasive detection of coronary vasospastic angina using a double-acquisition coronary CT angiography protocol in the presence and absence of an intravenous nitrate: a pilot study

ObjectivesTo evaluate the feasibility of a double-acquisition coronary CT angiography (CCTA) protocol in the presence and absence of an intravenous (IV) vasodilator infusion for detecting vasospastic angina.MethodsTwenty patients with a high clinical probability of vasospastic angina were enrolled. All subjects underwent baseline CCTA without a vasodilator in the early morning followed by a catheterized coronary angiography with ergonovine provocation test. Within 3xa0days, all subjects underwent repeat CCTA during a continuous IV infusion of nitrate. Vasospastic angina as detected by CCTA was defined as significant stenosis (≥50xa0%) with negative remodelling without definite plaques or diffuse small diameter (<2xa0mm) of a major coronary artery with a beaded appearance on baseline CT that completely dilated on IV nitrate CT. The CCTA results were compared to the catheterized ergonovine provocation test as the reference standard.ResultsAmong 20 patients, the catheterized ergonovine provocation test detected vasospasm in 15 patients. The sensitivity, specificity, positive predictive value and negative predictive value of CCTA in a per-patient-based analysis were 73, 100, 100 and 56xa0%, respectively.ConclusionsDouble-acquisition CCTA in the presence and absence of IV infusion of nitrate allows noninvasive detection of vasospastic angina with moderate sensitivity and high specificity.Key Points• Limited data exist regarding the efficacy of CCTA in detecting vasospastic angina.• We propose a double-acquisition CCTA protocol with and without IV nitrate injections.• This protocol provides 100% specificity and moderate sensitivity (73%) in spasm detection.

Effect of Hybrid Kernel and Iterative Reconstruction on Objective and Subjective Analysis of Lung Nodule Calcification in Low-Dose Chest CT

Objective To evaluate the differences in subjective calcification detection rates and objective calcium volumes in lung nodules according to different reconstruction methods using hybrid kernel (FC13-H) and iterative reconstruction (IR). Materials and Methods Overall, 35 patients with small (< 4 mm) calcified pulmonary nodules on chest CT were included. Raw data were reconstructed using filtered back projection (FBP) or IR algorithm (AIDR-3D; Canon Medical Systems Corporation), with three types of reconstruction kernel: conventional lung kernel (FC55), FC13-H and conventional soft tissue kernel (FC13). The calcium volumes of pulmonary nodules were quantified using the modified Agatston scoring method. Two radiologists independently interpreted the role of each nodule calcification on the six types of reconstructed images (FC55/FBP, FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D). Results Seventy-eight calcified nodules detected on FC55/FBP images were regarded as reference standards. The calcium detection rates of FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D protocols were 80.7%, 15.4%, 6.4%, 52.6%, and 28.2%, respectively, and FC13-H/AIDR-3D showed the smallest calcium detection rate. The calcium volume varied significantly with reconstruction protocols and FC13/AIDR-3D showed the smallest calcium volume (0.04 ± 0.22 mm3), followed by FC13-H/AIDR-3D. Conclusion Hybrid kernel and IR influence subjective detection and objective measurement of calcium in lung nodules, particularly when both techniques (FC13-H/AIDR-3D) are combined.