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1.  Clinical results of XMR-assisted percutaneous transforaminal endoscopic lumbar discectomy 
Although percutaneous endoscopic lumbar discectomy (PELD) has shown favorable outcomes in the majority of lumbar discectomy cases, there were also some failures. The most common cause of failure is the incomplete removal of disc fragments. The skin entry point for the guide-needle trajectory and the optimal placement of the working sleeve are largely blind, which might lead to the inadequate removal of disc fragments. The objective of this study was to present our early experiences with image-guided PELD using a specially designed fluoroscope with magnetic resonance imaging-equipped operative suite (XMR) for the treatment of lumbar disc herniation.
This prospective study included 89 patients who had undergone PELD via the transforaminal approach using an XMR protocol. Pre- and postoperative examinations (at 12 weeks) included a detailed clinical history, visual analogue scale (VAS), Oswestry disability index (ODI), and radiological workups. The results were categorized as excellent, good, fair, and poor according to MacNab's criteria. At the final follow-up, the minimum follow-up time for the subjects was 2 years. The need for revision surgeries and postoperative complications were noted on follow-up.
Postoperative mean ODI decreased from 67.4% to 5.61%. Mean VAS score for back and leg pain improved significantly from 4 to 2.3 and from 7.99 to 1.04, respectively. Four (4.49%) patients underwent a second-stage PELD after intraoperative XMR had shown remnant fragments after the first stage. As per MacNab's criteria, 76 patients (85.4%) showed excellent, 8 (8.89%) good, 3 (3.37%) fair, and 2 (2.25) poor results. Four (4.49%) patients had remnant disc fragments on XMR, which were removed during the same procedure. All of these patients had either highly migrated or sequestrated disc fragments preoperatively. Four (4.49%) other patients needed a second, open surgery due to symptomatic postoperative hematoma (n = 2) and recurrent disc herniation (n = 2).
This prospective analysis indicates that XMR-assisted PELD provides a precise skin entry point. It also confirms that decompression occurs intraoperatively, which negates the need for a separate surgery and thus increases the success rate of PELD, particularly in highly migrated or sequestrated discs. However, further extensive experience is required to confirm the advantages and feasibility of PELD in terms of cost effectiveness.
PMCID: PMC3668223  PMID: 23705685
Percutaneous endoscopic lumbar discectomy; Incomplete disc removal; XMR-guided procedure; High success rate
2.  Piriformis syndrome after percutaneous endoscopic lumbar discectomy via the posterolateral approach 
European Spine Journal  2011;20(10):1663-1668.
Percutaneous endoscopic lumbar discectomy (PELD) can be performed under local anesthesia with intravenous analgesics. To define the incidence of piriformis syndrome (PS) after PELD via the posterolateral approach under local anesthesia compared to that of general patients presenting with low back pain with/without lower leg pain. The incidence and time of occurrence of positive FAIR test after PELD within a 3-month follow-up period were evaluated retrospectively, and compared with the prevalence of general patients who visited the pain clinic for LBP with/without lower leg pain. Factors that may increase the incidence of PS after PELD were also evaluated. There was no patient with positive FAIR test immediately after PELD in the operation room and before walking. The prevalence of PS in general patients was 317/2,320 (13.7%); however, the incidence of PS after PELD within a 3-month follow-up period was 61/151 (40.4%), peaking at 32 days. High anxiety scale scores during operation led to increased incidence of PS after PELD. PELD under local anesthesia with high level of anxiety may increase the incidence of PS after walking, peaking around the first month, compared with the results for general patients with low back pain with/without lower leg pain.
PMCID: PMC3175870  PMID: 21416279
Diskectomy; Endoscopy; Lumbar vertebrae; Percutaneous; Piriformis syndrome
3.  Use of Lidocaine Patch for Percutaneous Endoscopic Lumbar Discectomy 
The Korean Journal of Pain  2011;24(2):74-80.
Lidocaine patch (L5P) has demonstrated short-term efficacy in treating both acute surgical pain and chronic neuropathic pain with tolerable side effects. Percutaneous endoscopic lumbar discectomy (PELD) is the mainstay of minimally invasive spine surgery (MISS). Sufficient analgesia during PELD surgery makes the patient consider it real MISS. This study was performed to evaluate the efficacy and adverse effects of lidocaine patch in patients who underwent PELD under local anesthesia.
L5P (L group) or placebo (P group) was randomly applied on the skin of the back covering the anticipated path of the working channel before 1 hour of surgery in 100 patients who underwent a single level PELD at L4-L5. Efficacy of the lidocaine patch was assessed by patient's numeric rating scale (NRS) of pain at each stage during the surgery and by a 5-scale grading of the satisfaction with the anesthesia of the operator and patients after surgery.
Mean NRS scores at the stages of needle insertion, skin incision, serial dilation and insertion of working channel, and subcutaneous suture were significantly lower in the L group than the P group. Postoperative operator's and patients' satisfaction scores were also significantly higher in L group than in the P group. There were subtle adverse effects in both groups.
L5P provided better pain relief during PELD, especially at the stage of needle insertion, skin incision, serial dilation and insertion of working channel, and subcutaneous suture. It also provided higher patient and operator postoperative satisfaction, with only subtle adverse effects.
PMCID: PMC3111563  PMID: 21716614
analgesia; endoscopy; lidocaine; percutaneous discectomy; transdermal patch
4.  Dural tears in percutaneous endoscopic lumbar discectomy 
European Spine Journal  2010;20(1):58-64.
The objective of the study was to demonstrate the clinical characteristics of dural tears during percutaneous endoscopic lumbar discectomy (PELD) and to discuss how to prevent this unintended complication. The study used data from 816 consecutive patients who underwent PELD between 2003 and 2007. A total of nine patients (1.1%) experienced symptomatic dural tears. The clinical outcomes were evaluated using the visual analogue scale (VAS), the Oswestry disability index (ODI), and modified MacNab criteria. Intractable radicular pain was the most common symptom, while classical manifestations, such as CSF leakage or wound swelling, were rare. In three of the nine cases, the dural tears were detected intraoperatively, while the remaining six cases were not recognized during the procedure. Among the unrecognized patients, two patients were found with nerve root herniation causing profound neurological deficits. All patients were managed by secondary open repair surgeries. The mean follow-up period was 30.8 months. The mean VAS of radicular leg pain improved from 8.3 to 2.6, and that of back pain improved from 4.1 to 2.6. The mean ODI improved from 69.6 to 29.2%. The final outcomes were excellent in one, good in five, fair in one, and poor in two patients. As application of the endoscopic procedure has been broadened to more complex cases, the risk of dural tears may increase. Unrecognized dural tear with nerve root herniation may cause permanent neurological sequelae. Accurate information and proper technical considerations are essential to prevent this unpredictable complication.
PMCID: PMC3036033  PMID: 20582555
Dural tear; Endoscopic discectomy; Complication; Nerve root herniation
5.  Percutaneous pedicle screw placement in the thoracic spine: A cadaveric study 
Asian Journal of Neurosurgery  2013;8(3):153-156.
Study Design:
A cadaveric study to determine the accuracy of percutaneous screw placement in the thoracic spine using standard fluoroscopic guidance.
Summary of Background Data:
While use of percutaneous pedicle screws in the lumbar spine has increased rapidly, its acceptance in the thoracic spine has been slower. As indications for pedicle screw fixation increase in the thoracic spine so will the need to perform accurate and safe placement of percutaneous screws with or without image navigation. To date, no study has determined the accuracy of percutaneous thoracic pedicle screw placement without use of stereotactic imaging guidance.
Materials and Methods:
Eighty-six thoracic pedicle screw placements were performed in four cadaveric thoracic spines from T1 to T12. At each level, Ferguson anterior–posterior fluoroscopy was used to localize the pedicle and define the entry point. Screw placement was attempted unless the borders of the pedicle could not be delineated solely using intraoperative fluoroscopic guidance. The cadavers were assessed using pre- and postprocedural computed tomography (CT) scans as well as dissected and visually inspected in order to determine the medial breach rate.
Ninety pedicles were attempted and 86 screws were placed. CT analysis of screw placement accuracy revealed that only one screw (1.2%) breached the medial aspect of the pedicle by more than 2 mm. A total of four screws (4.7%) were found to have breached medially by visual inspection (three Grade 1 and one Grade 2). One (1.2%) lateral breach was greater than 2 mm and no screw violated the neural foramen. The correlation coefficient of pedicle screw violations and pedicle diameter was found to be 0.96.
This cadaveric study shows that percutaneous pedicle screw placement can be performed in the thoracic spine without a significant increase in the pedicle breach rate as compared with standard open techniques. A small percentage (4.4%) of pedicles, especially high in the thoracic spine, may not be safely visualized.
PMCID: PMC3877502  PMID: 24403958
Minimally invasive surgery; pedicle screw; thoracic spine
6.  Comparison of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Microdiscectomy for Recurrent Disc Herniation 
The purpose of this study was to compare clinical and radiological outcomes of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy (OLM) for recurrent disc herniation.
Fifty-four patients, who underwent surgery, either PELD (25 patients) or repeated OLM (29 patients), due to recurrent disc herniation at L4-5 level, were divided into two groups according to the surgical methods. Excluded were patients with sequestrated disc, calcified disc, severe neurological deficit, or instability. Clinical outcomes were assessed using Visual Analogue Scale (VAS) score and Oswestry Disability Index (ODI). Radiological variables were assessed using plain radiography and/or magnetic resonance imaging.
Mean operating time and hospital stay were significantly shorter in PELD group (45.8 minutes and 0.9 day, respectively) than OLM group (73.8 minutes and 3.8 days, respectively) (p < 0.001). Complications occurred in 4% in PELD group and 10.3% in OLM group in the perioperative period. At a mean follow-up duration of 34.2 months, the mean improvements of back pain, leg pain, and functional improvement were 4.0, 5.5, and 40.9% for PELD group and 2.3, 5.1, and 45.0% for OLM group, respectively. Second recurrence occurred in 4% after PELD and 10.3% after OLM. Disc height did not change after PELD, but significantly decreased after OLM (p = 0.0001). Neither sagittal rotation angle nor volume of multifidus muscle changed significantly in both groups.
Both PELD and repeated OLM showed favorable outcomes for recurrent disc herniation, but PELD had advantages in terms of shorter operating time, hospital stay, and disc height preservation.
PMCID: PMC2803265  PMID: 20062565
Reherniation; Discectomy; Lumbar spine
7.  Percutaneous endoscopic lumbar discectomy for migrated disc herniation: classification of disc migration and surgical approaches 
European Spine Journal  2006;16(3):431-437.
Percutaneous endoscopic lumbar discectomy (PELD) for migrated disc herniations is technically demanding due to the absence of the technical guideline. The purposes of this study were to propose a radiologic classification of disc migration and surgical approaches of PELD according to the classification. A prospective study of 116 consecutive patients undergoing single-level PELD was conducted. According to preoperative MRI findings, disc migration was classified into four zones based on the direction and distance from the disc space: zone 1 (far up), zone 2 (near up), zone 3 (near down), zone 4 (far down). Two surgical approaches were used according to this classification. Near-migrated discs were treated with “half-and-half” technique, which involved positioning a beveled working sheath across the disc space to the epidural space. Far-migrated discs were treated with “epiduroscopic” technique, which involved introducing the endoscope into the epidural space completely. The mean follow-up period was 14.5 (range 9–20) months. According to the Macnab criteria, satisfactory results were as follows: 91.6% (98/107) in the down-migrated discs; 88.9% (8/9) in the up-migrated discs; 97.4% (76/78) in the near-migrated discs; and 78.9% (30/38) in the far-migrated discs. The mean VAS score decreased from 7.5 ± 1.7 preoperatively to 2.6 ± 1.8 at the final follow-up (P < 0.0001). There were no recurrence and no approach-related complications during the follow-up period. The proposed classification and approaches will provide appropriate surgical guideline of PELD for migrated disc herniation. Based on our results, open surgery should be considered for far-migrated disc herniations.
PMCID: PMC2200706  PMID: 16972067
Percutaneous endoscopic lumbar discectomy; Migrated disc herniation; Radiologic classification
8.  Pediatric Liver Transplantation Outcomes in Korea 
Pediatric liver transplantation is the standard of care for treatment of liver failure in children. The aim of this study was to identify the characteristics of pediatric liver transplantation in centers located in Korea and determine factors that influence outcomes. This retrospective study was performed using data from between 1988 and 2010 and included all recipients 18 yr old and younger who underwent pediatric liver transplantation in Korea during that period. Our data sources were hospital medical records and the outcome measure was overall patient survival. Univariate and multivariate statistical analyses were undertaken using the Cox proportional hazards model. Five hundred and thirty-four pediatric liver transplantations were performed in 502 children. Median age and average pediatric end-stage liver disease (PELD) score were 20 months and 18 point, respectively. Biliary atresia (57.7%, 308/534) was the most common cause of liver disease. Eighty-two (15.3%) were deceased donor liver transplantations and 454 (84.7%) were living donor liver transplantations. Retransplantation was performed in 32 cases (6%). Overall, 1-, 5-, and 10-yr patient survival rates were 87.8%, 82.2%, and 78.1%, respectively. In multivariate analysis, independent significant predictors of poor patient survival were chronic rejection and retransplantation. This study presents the epidemiologic data for nearly all pediatric liver transplantation in Korea and shows that the independent prognostic factors in patient survival are chronic rejection and retransplantation.
PMCID: PMC3546103  PMID: 23341710
Liver Transplantation; Children; Survival; Rejection; Retransplantation
9.  An Alternative Approach to Needle Placement in Cervicothoracic Epidural Injections 
The Korean Journal of Pain  2012;25(3):183-187.
The use of fluoroscopy guidance together with the loss of resistance technique during epidural injections has been advocated lately; moreover, epidural injections in the absence of fluoroscopic guidance have a high rate of inaccurate needle-tip placement during the injections. However, the approach to the lower cervical and upper thoracic epidural space may be challenging due to its obscure lateral fluoroscopic views from overlying normal tissue structures. In this case, we report an alternative oblique C-arm fluoroscopy guided view approach to supplement the standard anterior-posterior and lateral fluoroscopic views to facilitate successful needle placement and precise anatomical localization of the epidural space.
PMCID: PMC3389323  PMID: 22787549
alternative; epidural; fluoroscopy; oblique
10.  Fluoroscopically guided transforaminal epidural dry needling for lumbar spinal stenosis using a specially designed needle 
This report describes the methodological approach and clinical application of a minimally invasive intervention to treat lumbar spinal stenosis (LSS).
Thirty-four patients with LSS underwent fluoroscopically guided transforaminal epidural dry needling using a specially designed flexed Round Needle. The needle was inserted 8-12 cm lateral to the midline at the level of the stenosis and advanced to a position between the anterior side of the facet joint and pedicle up to the outer-third of the pedicle. The needle was advanced medially and backed laterally within a few millimetres along the canal side of the inferior articular process between the facet joint and pedicle. The procedure was completed when a marked reduction in resistance was felt at the tip of the needle. The procedure was performed bilaterally at the level of the stenosis.
The average follow-up period was 12.9 ± 1.1 months. The visual analogue scale (VAS) pain score was reduced from 7.3 ± 2.0 to 4.6 ± 2.5 points, the Oswestry Disability Index (ODI) score decreased from 41.4 ± 17.2 to 25.5 ± 12.6% and the average self-rated improvement was 52.6 ± 33.1%. The VAS scores indicated that 14 (41.2%) patients reported a "good" to "excellent" treatment response, while 11 (32.4%) had a "good" to "excellent" treatment response on the ODI and 22 (64.7%) had a "good" to "excellent" treatment response on the self-rated improvement scale.
These results suggest that fluoroscopically guided transforaminal epidural dry needling is effective for managing LSS.
PMCID: PMC2927508  PMID: 20698999
11.  Robotically Driven Interventions: A Method of Using CT Fluoroscopy without Radiation Exposure to the Physician1 
Radiology  2002;225(1):277-282.
Radiation exposure to physicians’ hands during interventional procedures with computed tomography (CT) fluoroscopic guidance may be high. A robot was developed that could hold, orient, and advance a needle, with CT fluoroscopic guidance. This robot could be either computer or joystick controlled. Twenty-three robotically guided percutaneous interventions were performed without complication. Physician radiation exposure was negligible during the CT fluoroscopy–guided procedures.
PMCID: PMC3107539  PMID: 12355016
Computed tomography (CT), guidance, 70.12119; Computed tomography (CT), radiation exposure, 70.12119; Fluoroscopy, technology; Phantoms; Radiations, exposure to patients and personnel, 70.12119; Radiations, measurement, 70.12119
12.  Fluoroscope guided epidural needle insertioin in midthoracic region: clinical evaluation of Nagaro's method 
Korean Journal of Anesthesiology  2012;62(5):441-447.
In the midthoracic region, a fluroscope guided epidural block has been proposed by using a pedicle as a landmark to show the height of the interlaminar space (Nagaro's method). However, clinical implication of this method was not fully evaluated. We studied the clinical usefulness of a fluoroscope guided thoracic epidural block in the midthoracic region.
Twenty four patients were scheduled to receive an epidural block at the T6-7 intervertebral space. The patients were placed in the prone position. The needle entry point was located at the junction between midline of the pedicle paralleled to the midline of the T7 vertebral body (VB) and the lower border of T7 VB on anteroposterior view of the fluoroscope. The needle touched and walked up the lamina, and the interlaminar space (ILS) was sought near the midline of the VB at the height of the pedicle.
The authors could not insert an epidural needle at T6-7 ILS in two patients and it was instead inserted at T5-6 ILS. However, other patients showed easy insertion at T6-7 ILS. The mean inward and upward angulations were 25° and 55° respectively. The mean actual depth and calculated depth from skin to thoracic epidural space were 5.1 cm and 6.1 cm respectively. Significant correlation between actual needle depth and body weight, podendal index (kg/m) or calculated needle depth was noted.
The fluorposcope guided epidural block by Nagaro's method was useful in the midthoracic region. However, further study for the caudal shift of needle entry point may be needed.
PMCID: PMC3366311  PMID: 22679541
Analgesia; Epidural; Fluoroscopy; Thoracic vertebrae
13.  Real-time CT Fluoroscopy (CTF)-Guided Vertebroplasty in Osteoporotic Spine Fractures 
Yonsei Medical Journal  2005;46(5):635-642.
The purpose of this study was to evaluate the clinical feasibility, benefits, and limitations of CT fluoroscopy (CTF)-guided percutaneous vertebroplasty (PVP). PVP under the guidance of CTF without additional guidance by conventional C-arm fluoroscopy was performed in a total of 29 vertebral bodies in 21 patients with vertebral compression fractures. While monitoring sectional CTF images, the needle was advanced from the skin to the target vertebra. Contrast media and polymethylmethacrylate (PMMA) were injected into the target vertebra with careful monitoring of their distribution. After the procedure, an evaluation was conducted to determine whether extraosseous leakage of PMMA occurred and whether sufficient filling of PMMA had been achieved. Needle placement into the target vertebra was easily achieved with both the transpedicular and posterolateral approaches. Injection of PMMA and venous leakage of contrast media were carefully monitored in all patients, and early detection of PMMA leaking was achieved in 5 patients. Extraosseous leakage that had not been detected during the procedure was not found upon postoperative evaluation. Pain scales were significantly decreased after the procedure, and no obvious complications occurred following the procedure. CTF-guided PVP without the combined use of C-arm fluoroscopy was feasible and showed definite benefits. We believe that, in spite of some limitations, CTF-guided PVP provides an alternative technique appropriate in certain situations.
PMCID: PMC2810568  PMID: 16259060
Compression fracture; osteoporosis; vertebroplasty; CT fluoroscopy
14.  Effect on biopsy technique of the breast imaging reporting and data system (BI-RADS) for nonpalpable mammographic abnormalities 
Canadian Journal of Surgery  2002;45(4):259-263.
To determine if the breast imaging reporting and data system (BI-RADS) defines a group of patients with mammographic abnormalities in whom stereotactic core needle biopsy (SCNB) is appropriate.
A blinded retrospective validation sample.
A university-affiliated hospital.
One hundred and nine consecutive patients who underwent fine-wire localization breast biopsy (FWLB) between Jan. 1, 1994, and June 1, 1999, with a known final pathological diagnosis.
Blinded mammographic review and classification using the BI-RADS; review of corresponding pathological findings from FWLBs.
Outcome measures
Correlation of pathological findings with each BI-RADS category and analysis of the predictive value of clinical and radiologic features.
BI-RADS findings were as follows: 0 malignant lesions in 10 category 3 cases, 18 malignant lesions (3 in situ, 15 invasive) in 68 category 4 cases and 24 malignant lesions (8 in situ and 16 invasive) in 31 category 5 cases. There was 1 malignant lesion in 22 category 4 cases in women younger than 50 years.
SCNB should be applied to BI-RADS categories 3 and 4 (< 50 yr of age). FWLB should be reserved for category 4 (> 50 yr of age) and category 5 cases. This algorithm will reduce the morbidity and cost of breast biopsies in patients with nonpalpable mammographic abnormalities.
PMCID: PMC3684677  PMID: 12174979
15.  Percutaneous Jejunostomy 
Direct percutaneous jejunostomy is considered in patients where percutaneous gastrostomy is not feasible (stomach removed or inaccessible). Percutaneous jejunostomy is more difficult than gastrostomy techniques. Direct jejunostomy is performed under fluoroscopic guidance, using a nasojejunal tube to distend the jejunum. The jejunal loop is punctured using a Cope suture anchor, under ultrasound guidance. Water-soluble contrast material is injected through the needle to document intralumenal position, and an anchor is inserted. With the guide wire in place, the track is dilated and a 10-F pigtail catheter inserted into the proximal jejunum. Fluoroscopy can also be used to aid puncture using dilute contrast material, if used via the nasogastric tube. Antiperistaltic agents can also be used to aid jejunal puncture. The cumulative procedure-related mortality from the three reported series in the literature is 2.4%, with minor complications occurring in 10 to 11%. Although jejunostomy is not performed frequently, this is a feasible procedure for interventional radiology.
PMCID: PMC3036227  PMID: 21331129
Percutaneous jejunostomy; jejunal obstruction
16.  A blunt needle (Epimed®) does not eliminate the risk of vascular penetration during transforaminal epidural injection 
Surgical Neurology International  2013;4(Suppl 5):S404-S406.
Transforaminal epidural injection of local anesthetics and corticosteroids is a common practice in patients with radicular pain. However, serious morbidity has also been reported, which can be attributed to an arterial or venous injection of the medication especially particulate glucocorticoid preparations. Using a blunt needle in contrast to sharp needle has been suggested to reduce this risk in a study on animals.
Case Description:
We present a 59-year-old female with L5 lumbar radicular symptoms and left L5-S1 foraminal narrowing who underwent transforaminal epidural injection with fluoroscopic guidance using a 22-gauge blunt curved needle (Epimed®, Johnstown, NY). Intravascular needle placement was detected during real-time contrast injection under live fluoroscopy after a negative aspiration and local anesthetic test dose. The needle was slightly withdrawn and correct distribution of the contrast was confirmed along the target nerve root and into the epidural space.
This case report discusses vascular penetration utilizing an Epimed® blunt needle to perform transforaminal injections in a clinical setting. This topic was previously discussed in earlier animal studies. We also reemphasize that neither negative aspiration or local anesthetic test doses are reliable techniques to ensure the safety of transforaminal epidural injections.
PMCID: PMC3841942  PMID: 24340239
Blunt needle; fluoroscopy; intravascular penetration; radicular pain; transforaminal epidural injection
17.  Percutaneous discography: comparison of low-dose CT, fluoroscopy and MRI in the diagnosis of lumbar disc disruption 
European Spine Journal  2005;15(5):620-626.
Aim: To compare the diagnostic accuracy of low-dose computed tomography (CT), magnetic resonance imaging (MRI) and fluoroscopy in percutaneous discography in patients scheduled for lumbar spondylodesis. Material and methods: Within a prospective pilot study, 18 disc segments of 11 patients with radicular or pseudoradicular pain prior to anteroposterior spondylodesis were evaluated. After injection of a mixture of non-ionic iodine-containing contrast agent and gadolinium-based contrast medium into the disc spaces, all patients underwent conventional fluoroscopy, as well as low-dose CT and MRI. The occurrence of memory pain during contrast injection was recorded. CT, MRI and fluoroscopic images were analyzed independently by two readers blinded to the clinical findings. Results: There was 100% agreement between CT and MRI discography in the detection, localization and grading of degenerative changes. In contrast, conventional fluoroscopy identified only 9 of the 12 abnormal segments. Memory pain following puncture was identified in 3 of the 12 affected segments. Summary: Low-dose CT and MRI discography have a similar accuracy in the assessment of disc disruption and they are superior to fluoroscopic discography.
PMCID: PMC3489334  PMID: 16292635
Computed tomography; Low dose; Magnetic resonance imaging; Discography
18.  Fluoroscopy-Guided Percutaneous Gallstone Removal Using a 12-Fr Sheath in High-Risk Surgical Patients with Acute Cholecystitis 
Korean Journal of Radiology  2011;12(2):210-215.
To evaluate the technical feasibility and clinical efficacy of percutaneous transhepatic cholecystolithotomy under fluoroscopic guidance in high-risk surgical patients with acute cholecystitis.
Materials and Methods
Sixty-three consecutive patients of high surgical risk with acute calculous cholecystitis underwent percutaneous transhepatic gallstone removal under conscious sedation. The stones were extracted through the 12-Fr sheath using a Wittich nitinol stone basket under fluoroscopic guidance on three days after performing a percutaneous cholecystostomy. Large or hard stones were fragmented using either the snare guide wire technique or the metallic cannula technique.
Gallstones were successfully removed from 59 of the 63 patients (94%). Reasons for stone removal failure included the inability to grasp a large stone in two patients, and the loss of tract during the procedure in two patients with a contracted gallbladder. The mean hospitalization duration was 7.3 days for acute cholecystitis patients and 9.4 days for gallbladder empyema patients. Bile peritonitis requiring percutaneous drainage developed in two patients. No symptomatic recurrence occurred during follow-up (mean, 608.3 days).
Fluoroscopy-guided percutaneous gallstone removal using a 12-Fr sheath is technically feasible and clinically effective in high-risk surgical patients with acute cholecystitis.
PMCID: PMC3052612  PMID: 21430938
Gallbladder stone; Acute cholecystitis; Percutaneous cholecystolithotomy
19.  Computed tomography-guided vertebroplasty using a stereotactic guidance system (stereo-guide) 
In order to make it easy to perform computed tomography (CT)-guided vertebroplasty a stereotactic guidance system called the "stereo-guide" was designed. A method to perform CT-guided vertebroplasty using this system is described.
The device is a rectangular flat plastic block. One of the flat surfaces of the block has deeply grooved protractor markings at 5-degree intervals; ranging from 0 to 30 degrees. The procedure is performed on the CT table. Based on distances and angle measurements obtained from CT images the device is placed on an appropriate location on the back of the patient and the needle is advanced to the target through the pedicle guided by the grooves on the device. Ten procedures were performed in nine patients with lumbar and thoracic pathology.
The system was easy to use and proved to be accurate. No complication resulted from the procedure.
The stereo-guide proved to be simple and easy to use. Intraoperative scans helped to plan the trajectory and follow the injection of the cement.
PMCID: PMC2908353  PMID: 20657698
Computed tomography guidance; stereotactic; vertebral fracture; vertebroplasty
20.  Use of a novel coaxial guide needle-wire (GNW) combination system for computed tomography guided radiofrequency tumor ablation 
We developed a novel coaxial system using a fine guide needle wire (GNW) to safely and easily place the radiofrequency needle under CT-guidance. The GNW consists of a fine needle (diameter, 21-gauge; length, 150 mm) and a wire (0.018 inch, 250 mm). An exclusive radiofrequency cannula (14-gauge; 160 mm) was also used. This system was used for the treatment of six hepatocellular carcinomas in six patients. All lesions were located deeper than 10 cm from the needle entry site. This system was useful in performing CT-guided RF ablation for deeply or precariously located liver lesions particularly in patients who are unable to hold their breath.
PMCID: PMC3204259  PMID: 21995771
21.  3D cone-beam CT guidance, a novel technique in renal biopsy—results in 41 patients with suspected renal masses 
European Radiology  2012;22(11):2547-2552.
To determine whether 3D cone-beam computed tomography (CBCT) guidance allows safe and accurate biopsy of suspected small renal masses (SRM), especially in hard-to-reach anatomical locations.
Materials and methods
CBCT guidance was used to perform 41 stereotactic biopsy procedures of lesions that were inaccessible for ultrasound guidance or CT guidance. In CBCT guidance, a 3D-volume data set is acquired by rotating a C-arm flat-panel detector angiosystem around the patient. In the data set, a needle trajectory is determined and, after co-registration, a fusion image is created from fluoroscopy and a slice from the data set, enabling the needle to be positioned in real time.
Of the 41 lesions, 22 were malignant, 17 were benign, and 2 were nondiagnostic. The two nondiagnostic lesions proved to be renal cell carcinoma. There was no growth during follow-up imaging of the benign lesions (mean 29 months). This resulted in a sensitivity, specificity, PPV, NPV, and accuracy of 91.7, 100, 100, 89.5, and 95.1%, respectively. Mean dose-area product value was 44.0 Gy·cm2 (range 16.5–126.5). There was one minor bleeding complication.
With CBCT guidance, safe and accurate biopsy of a suspected SRM is feasible, especially in hard-to-reach locations of the kidney.
Key Points
• Cone-beam computed tomography has potential advantages over conventional CT for interventional procedures.
• CBCT guidance incorporates 3D CBCT data, fluoroscopy, and guidance software.
• In hard-to-reach renal masses, CBCT guidance offers an alternative biopsy method.
• CBCT guidance offers good outcome and safety and has potential clinical significance.
PMCID: PMC3472072  PMID: 22660984
Percutaneous biopsy; Cone-beam CT; Small renal masses; Outcome; Hard-to-reach
22.  Interventional robotic systems: Applications and technology state-of-the-art 
Many different robotic systems have been developed for invasive medical procedures. In this article we will focus on robotic systems for image-guided interventions such as biopsy of suspicious lesions, interstitial tumor treatment, or needle placement for spinal blocks and neurolysis. Medical robotics is a young and evolving field and the ultimate role of these systems has yet to be determined. This paper presents four interventional robotics systems designed to work with MRI, CT, fluoroscopy, and ultrasound imaging devices. The details of each system are given along with any phantom, animal, or human trials. The systems include the AcuBot for active needle insertion under CT or fluoroscopy, the B-Rob systems for needle placement using CT or ultrasound, the INNOMOTION for MRI and CT interventions, and the MRBot for MRI procedures. Following these descriptions, the technology issues of image compatibility, registration, patient movement and respiration, force feedback, and control mode are briefly discussed. It is our belief that robotic systems will be an important part of future interventions, but more research and clinical trials are needed. The possibility of performing new clinical procedures that the human cannot achieve remains an ultimate goal for medical robotics. Engineers and physicians should work together to create and validate these systems for the benefits of patients everywhere.
PMCID: PMC3107540  PMID: 16754193
Medical robotics; minimally invasive procedures; interventional robots; image-guided interventions; MR-guided interventions
23.  Modes of Action of Five Different Endopectate Lyases from Erwinia chrysanthemi 3937 
Journal of Bacteriology  1999;181(12):3705-3709.
Five endopectate lyases from the phytopathogenic bacterium Erwinia chrysanthemi, PelA, PelB, PelD, PelI, and PelL, were analyzed with respect to their modes of action on polymeric and oligomeric substrates (degree of polymerization, 2 to 8). On polygalacturonate, PelB showed higher reaction rates than PelD, PelI, and PelA, whereas the reaction rates for PelL were extremely low. The product progression during polygalacturonate cleavage showed a typical depolymerization profile for each enzyme and demonstrated their endolytic character. PelA, PelI, and PelL released oligogalacturonates of different sizes, whereas PelD and PelB released mostly unsaturated dimer and unsaturated trimer, respectively. Upon prolonged incubation, all enzymes degraded the primary products further, to unsaturated dimer and trimer, except for PelL, which degraded the primary products to unsaturated tetramer and pentamer in addition to unsaturated dimer and trimer. The bond cleavage frequencies on oligogalacturonates revealed differences in the modes of action of these enzymes that were commensurate with the product progression profiles. The preferential products formed from the oligogalacturonates were unsaturated dimer for PelD, unsaturated trimer for PelB, and unsaturated tetramer for PelI and PelL. For PelA, preferential products were dependent on the sizes of the oligogalacturonates. Whereas PelB and PelD displayed their highest activities on hexagalacturonate and tetragalacturonate, respectively, PelA, PelI, and PelL were most active on the octamer, the largest substrate used. The bond cleavage frequencies and reaction rates were used to estimate the number of subsites of each enzyme.
PMCID: PMC93847  PMID: 10368144
24.  Comparison of stereotactic core breast biopsy and open surgical biopsy results at a tertiary care hospital in Pakistan 
The purpose of this study was to determine the yield of stereotactic core breast biopsy and its cost-saving potential.
This observational study was conducted at the Department of Radiology at Aga Khan Hospital in Karachi. All female patients (n = 84) undergoing stereotactic core breast biopsy under mammographic guidance from January 2005 to May 2010 were included. Stereotactic core biopsy was performed on a dedicated mammography unit employing a 14-gauge needle with an automated biopsy device. Ten patients with incomplete medical records were excluded. All breast biopsy results were either compared with surgical findings in cases of malignant histopathological findings or with follow-up needle localization in case of benign core biopsy findings.
Fifteen of our 74 patients had malignant findings on stereotactic biopsy, confirmed on histopathology of the final surgical mastectomy specimen. The remaining 59 patients had benign results on histopathology; five patients had needle localization of the same area due to either suspicious mammographic findings or clinical suspicion of malignancy. All were proven to be histopathologically benign on open surgical biopsy. Fifty-four patients with benign results had follow-up mammograms, and the follow-up period was 18 months to 5 years. The sensitivity and specificity was 100%. The cost saving per patient was US$253.
Stereotactic core breast biopsy is a safe and cost-effective method for determining the nature of suspicious mammographic findings.
PMCID: PMC3140815  PMID: 21792341
stereotactic; breast biopsy; BI-RADS®; mammography
25.  Accuracy of Posterior Subtalar Joint Injection Without Fluoroscopy 
Injection into the posterior subtalar joint has not been validated for accuracy using radiographic end points. We asked whether needle placement into a normal posterior subtalar joint could be performed accurately and selectively by experienced surgeons without fluoroscopic guidance. Three fellowship-trained orthopaedic foot and ankle surgeons each injected the posterior subtalar joint of 20 cadaveric specimens using an anterolateral approach. Fluoroscopic images were obtained by an independent investigator and blinded. A separate fellowship-trained foot and ankle surgeon interpreted the images. Of 60 injections, 58 were accurate and two were extraarticular based on interpretation by an independent foot and ankle surgeon. Extravasation into the ankle occurred in 14 samples and into the peroneal sheath in two samples. Experienced surgeons can place intraarticular injections into a radiographically normal posterior subtalar joint without fluoroscopy with a high degree of accuracy. However, extravasation into the ankle or peroneal tendon sheath occurred in an unpredictable fashion, suggesting selectivity of injection placement is relatively limited without the use of fluoroscopy. Fluoroscopy may not be necessary for injections used solely for therapeutic purposes. However, if the injection is intended for diagnostic purposes or to assist in surgical decision-making or if the joint is abnormal, we recommend fluoroscopy to ensure the subtalar joint is the only anatomic structure impacted by the injection.
PMCID: PMC2565054  PMID: 18404293

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