Fluoroscopic Method Research Articles

Accuracy of percutaneous pedicle screws for thoracic and lumbar spine fractures: a prospective trial

The percutaneous insertion technique requires surgical skill and experience. However, there have been few clinical reports evaluating the accuracy of minimally invasive pedicle screw placement using the conventional fluoroscopy method. The purpose of this study was to evaluate the accuracy of percutaneous pedicle screw placement in the treatment of thoracic and lumbar spine fractures using two-plane conventional fluoroscopy. A prospective clinical trial was performed. A total of 502 percutaneous pedicle screws in 111 patients, all inserted with the assistance of conventional fluoroscopy, were evaluated. The safety and accuracy of pedicle screw placement were based on the evaluation of postoperative axial 3-mm slice computed tomography scans using the scoring system described by Zdichavsky et al. [Eur J Trauma 30:234-240, 2004; Eur J Trauma 30:241-247, 2004]. 427/502 pedicle screws (85 %) were classified as good and excellent concerning the best possible screw length and 494/502 (98 %) were found to have good or excellent position. One screw had to be revised due to medial position with a neurological deficit. This study demonstrates the feasibility of placing percutaneous posterior thoracolumbar pedicle screws with the assistance of conventional fluoroscopy. Minimally invasive transpedicular instrumentation is an accurate, reliable and safe method to treat a variety of spinal disorders, including thoracic and lumbar spine fractures.

Retrograde Drilling of Talar Osteochondritis Dissecans Lesions: A Feasibility and Accuracy Analysis of a Novel Electromagnetic Navigation Method Versus a Standard Fluoroscopic Method

A novel method using an electromagnetic navigation system (ENS) was developed, and its feasibility and accuracy for retrograde drilling procedures were evaluated and compared with the standard freehand fluoroscopic method in an experimental setting. A controlled laboratory study of 16 standard freehand fluoroscopically guided and 16 electromagnetically navigated retrograde drilling procedures was performed on 4 cadaveric human ankle joints. Four artificial cartilage lesions were consecutively set, 2 on the medial and 2 on the lateral talar dome. Drilling accuracy was measured in terms of the distance from the final position of the drill bit to the tip of the probe hook and the distance between the tip of the drill bit and the center of the cartilage lesion on the articular cartilage surface. Intraoperative fluoroscopy exposure times were documented, as were readjustments of drilling directions or complete restarts. All procedures were timed with a stopwatch. Successful retrograde drilling was accomplished in 12 cases with the standard fluoroscopy-guided technique and in all 16 ENS-guided procedures. The overall mean time for the fluoroscopy-guided procedures was 660.00 ± 239.87 seconds and the overall mean time for the ENS method was 308.06 ± 54.03 seconds, providing a mean time benefit of 420.13 seconds. The mean distance from the final position of the drill bit to the tip of the probe hook was 3.25 ± 1.29 mm for the standard method and 2.19 ± 0.54 mm for the ENS method, and the mean distance between the tip of the drill bit and the center of the cartilage lesion on the articular cartilage surface was 2.50 ± 0.97 mm for the standard method and 0.88 ± 0.81 mm for the ENS method. Compared with the standard fluoroscopic technique, the ENS method used in this study showed higher accuracy and a shorter procedure time and required no X-ray radiation. The novel method considerably improves on the standard operating procedure in terms of safety, operation time, and radiation exposure.

Accuracy Analysis of a Novel Electromagnetic Navigation Procedure Versus a Standard Fluoroscopic Method for Retrograde Drilling of Osteochondritis Dissecans Lesions of the Knee

Background: Retrograde drilling for osteochondritis dissecans (OCD) remains a challenging operation. Purpose: A novel radiation-free electromagnetic navigation system (ENS)–based method was developed and its feasibility and accuracy for retrograde drilling procedures evaluated and compared with the standard freehand fluoroscopic method in an experimental setting. Study Design: Controlled laboratory study. Methods: A controlled laboratory study with 16 standard freehand fluoroscopically and 16 electromagnetically guided retrograde drilling procedures was performed on 8 cadaveric human knees. Four artificial cartilage lesions (2 on each condyle) were set per knee. Drilling accuracy was determined by final distance from the tip of the drill bit to the tip of the probe hook (D1) and distance between the tip of the drill and the marked lesion on the cartilage surface (D2). Intraoperative fluoroscopy exposure times were documented, as were directional readjustments or complete restarts. All procedures were timed using a stopwatch. Results: Successful retrograde drilling was accomplished in all 16 cases using the novel ENS-based method and in 11 cases using the standard fluoroscopic technique. The overall mean time for the fluoroscopy-guided procedures was 10 minutes 55 seconds ± 3 minutes 19 seconds and for the ENS method was 5 minutes 34 seconds ± 38 seconds, providing a mean time benefit of 5 minutes 35 seconds (P < .001). Mean D1 was 3.8 ± 1.6 mm for the standard and 2.3 ± 0.6 mm using the ENS technique (P = .021), and mean D2 was 2.5 ± 1.3 mm for the standard and 0.9 ± 0.7 mm for the ENS-based method (P < .001). Conclusion: Compared with the standard fluoroscopic technique, the novel ENS-based method used in this study showed superior accuracy, required less time, and utilized no radiation. Clinical Relevance: The novel method improves a standard operating procedure in terms of accuracy, operation time for the retrograde drilling procedure, and radiation exposure.

In vivo sagittal plane kinematics of the FPV patellofemoral replacement

Isolated symptomatic patellofemoral osteoarthritis has been reported in 2% of men and 8% of women older than the age of 55years in the community. With the development of improved designs and surgical techniques, interest in the use of patellofemoral replacement has increased. The primary aim of the newer generation of patellofemoral replacement implant designs has been to more closely reproduce normal knee kinematics. This study compares the functional sagittal plane in vivo kinematics of a contemporary patellofemoral prosthesis, the FPV, with normal knee kinematics using the patella tendon angle and patella flexion angle relationships with the knee flexion angle. The in vivo kinematics for a group of 8 patients (15 knees) with patellofemoral replacement and 22 normal subjects was measured for both a step-up and a lunge exercise using an established fluoroscopic method. The patella tendon angle characteristics of the implanted knees were similar to those of the normal knees for the step-up exercise with a significant difference only observed at 50° knee flexion angle. For the lunge exercise, the patella tendon angle for the implanted knee was consistently lower than that measured for the normal knee. Overall the subjects had excellent clinical scores post-patellofemoral replacement showing a significant improvement from their pre-operative scores. The kinematics of the FPV implant was closer to normal than those of total knee implants; however, there were still differences from the normal knees. III.

Accuracy and Safety Assessment of Pedicle Screw Placement Using the Rapid Prototyping Technique in Severe Congenital Scoliosis

The application of rapid prototyping (RP) technique for improving accuracy of pedicle screw placement in congenital scoliosis is described in this study. To compare the accuracy and safety of pedicle screw placement in congenital scoliosis using the RP technique versus the conventional fluoroscopy. Maldeveloped vertebral components in congenital scoliosis leads to prolonged operation time and higher rate of screw misplacement. RP technique can enhance preoperative and perioperative planning. No data are available on the accuracy of pedicle screw fixation using the RP technique. Sixty-two consecutive patients with hemivertebra had undergone posterior-only hemivertebra resection. Pedicle screws were implanted either by the conventional intraoperative fluoroscopy technique (C-arm group; n=28) or the RP technique (RP group; n=34). Accuracy of pedicle screw placement was compared by postoperative computed tomographic scan. Seventy of 677 inserted screws were found to be misplaced, showing an overall accuracy of 89.7% (90.8% in the thoracic spine and 87.4% in the lumbar spine). In the C-arm group, 86.1% (167 of 194) and 82.0% (82 of 100) of screws were accurately placed in the thoracic and lumbar spine, respectively. While in the RP group, the respective screw placement accuracies were 94.4% (238 of 252) and 91.6% (120 of 131). In the C-arm and the RP groups, 94.8% (279 of 294) and 97.9% (375 of 383) of the screws were within the safety zone, respectively. Compared with the fluoroscopy method, the RP-assisted technique showed a shorter operation time and higher scoliosis correction rate. No neurovascular-related complication was observed with this technique during the study. The application of RP technique in congenital scoliosis can reduce the operation time, the risk of screw misplacement and its consequent complications. The use of RP technique in congenital scoliosis is safe and efficacious.

IN VIVO THREE-DIMENSIONAL KINEMATICS OF TOTAL KNEE REPLACEMENTS DURING OPEN AND CLOSED KINETIC CHAIN ACTIVITIES

Measurement of the three-dimensional (3D) motions and surface kinematics of total knee replacements (TKR) during different kinetic activities helps provide necessary knowledge for a better use of these activities for rehabilitation purposes. The 3D kinematics of the knee in eight patients with posterior cruciate ligament-retaining (PCL-retaining) mobile-bearing TKR were measured during sit-to-stand, a closed kinetic chain (CKC) activity, and active knee flexion/extension, an open kinetic chain (OKC) activity, using a single-plane, 3D fluoroscopy method. Angular, translational motions as well as the contact patterns of the prosthesis components were calculated. The joint angular motion patterns were not statistically different between the OKC and CKC activities, but different contact patterns were found. The knee joint center translated more anteriorly during OKC than during CKC activities. Compared to the CKC activity, the more anterior contact positions and smaller total displacements of the medial contact in the OKC activity may indicate a greater loading in PCL and a smaller contact area on the medial tibial plateau. Rehabilitation of patients with mobile-bearing TKR may have to consider the potential negative effects of the greater loadings in the PCL and greater stresses in the medial tibial plateau when using OKC as a training exercise.

Esophagus Silhouette Extraction and Reconstruction From Fluoroscopic Views for Cardiac Ablation Procedure Guidance

Cardiac ablation involves the risk of serious complications when thermal injury to the esophagus occurs. This paper proposes to reduce the risk of such injuries by a proactive visualization technique, improving physician awareness of the esophagus location in the absence of or in addition to a reactive monitoring device such as a thermal probe. This is achieved by combining a graphical representation of the esophagus with live fluoroscopy. Toward this goal, we present an automated method to reconstruct and visualize a 3-D esophagus model from fluoroscopy image sequences acquired using different C-arm viewing directions. In order to visualize the esophagus under fluoroscopy, it is first biomarked by swallowing a contrast agent such as barium. Images obtained in this procedure are then used to automatically extract the 2-D esophagus silhouette and reconstruct a 3-D surface of the esophagus internal wall. Once the 3-D representation has been computed, it can be visualized using fluoroscopy overlay techniques. Compared to 3-D esophagus imaging using CT or C-arm CT, our proposed fluoroscopy method requires low radiation dose and enables a simpler workflow on geometry-calibrated standard C-arm systems.

Effects of soft tissue artifacts on the calculated kinematics and kinetics of the knee during stair-ascent

Biomechanics of the knee during stair-ascent has mostly been studied using skin-marker-based motion analysis techniques, but no study has reported a complete assessment of the soft tissue artifacts (STA) and their effects on the calculated joint center translation, angles and moments at the knee in normal subjects during this activity. This study aimed to bridge the gap. Twelve young adults walked up a three-step stair while data were acquired simultaneously from a three-dimensional motion capture system, a force plate and a dynamic fluoroscopy system. The “gold standards” of poses of the knee were obtained using a 3D fluoroscopy method. The STA of the markers on the thigh and shank were then calculated, together with their effects on the calculated joint center translations, angles and moments at the knee. The STA of the thigh markers were greater than those on the shank, leading to significantly underestimated flexion and extensor moments, but overestimated joint center translations during the first half of the stance phase. The results will be useful for a better understanding of the normal biomechanics of the knee during stair-ascent, as a baseline for future clinical applications and for developing a compensation method to correct for the effects of STA.

Influence of soft tissue artifacts on the calculated kinematics and kinetics of total knee replacements during sit-to-stand

The current study aimed to quantify the soft tissue artifacts of selected markers on the thigh and shank, and their effects on the calculated joint center translations, angles and moments of the knee during sit-to-stand. Ten patients with total knee replacements rose from a chair under simultaneous surveillance of a motion capture system, a force-plate and a fluoroscopy system. The “true” poses of the thigh and shank were defined by those of the femoral and tibial components obtained using a three-dimensional fluoroscopy method. The soft tissue artifacts of the skin markers were calculated as their movement relative to the underlying prosthesis components. The joint center translations, angles and moments at the knee were also calculated separately using skin markers and the registered prosthesis poses. Considerable soft tissue artifacts were found, leading to significantly underestimated flexion and internal rotation angles, and extensor moments, but overestimated joint center translations and adduction. The current study provides accurate data of the kinematics and kinetics of total knee replacements during sit-to-stand. The effects of soft tissue artifacts on the calculated joint center translations, angles and moments were also quantified for the first time in the literature. The results may help in developing guidelines for using skin markers and in establishing databases in the biomechanical assessment of sit-to-stand in patients with total knee replacements.

Description and Assessment of a Common Reference Method for Fluoroscopic and Transesophageal Echocardiographic Localization and Guidance of Mitral Periprosthetic Transcatheter Leak Reduction

This study sought to describe and compare a novel fluoroscopic method and a 2-dimensional transesophageal echocardiographic (TEE) method to localize mitral periprosthetic leaks (PPLs) for transcatheter reduction. Transcatheter reduction of significant regurgitation represents a modern and attractive alternative to surgery for the treatment of mitral PPL in high-risk patients. Accurate localization and precise communication between the echocardiographer and the interventional cardiologist are essential for procedural success. We analyzed TEE and fluoroscopic studies of patients with mitral PPL who underwent multiplane 2-dimensional TEE-guided transcatheter reduction in our institution. Periprosthetic leaks were routinely localized using the "surgeon's-view" time-clock method during periprocedural TEE assessments. The 2-dimensional TEE examinations were later retrospectively reviewed by an echocardiographer blinded to procedural TEE findings. A corresponding surgeon's-view time-clock method was plotted for fluoroscopic PPL localization. Using this fluoroscopic method, offline fluoroscopic images were reviewed by an independent interventional cardiologist blinded to TEE results. Agreement between methods was evaluated. Complete imaging data were available for analysis in 20 patients who, between 2002 and 2009, underwent transcatheter reduction in which the defect was successfully crossed. There was excellent agreement between procedural TEE and retrospective TEE review for PPL localization (100%; p < 0.0001) and between fluoroscopic and procedural TEE localization (90%; 95% confidence interval [CI]: 77% to 100%; p = 0.0003). In the 2 cases where there was disagreement, fluoroscopic PPL localization was adjacent to TEE localization. The surgeon's-view time-clock method of localizing PPL using 2-dimensional TEE is highly reproducible and allows fluoroscopic localization using the same reference system with very good agreement.

Accuracy of single-plane fluoroscopy in determining relative position and orientation of total knee replacement components

The accuracy of estimating the relative pose between knee replacement components, in terms of clinical motion, is important in the study of knee joint kinematics. The objective of this study was to determine the accuracy of the single-plane fluoroscopy method in calculating the relative pose between the femoral component and the tibial component, along knee motion axes, while the components were in motion relative to one another. The kinematics of total knee replacement components were determined in vitro using two simultaneous methods: single-plane fluoroscopic shape matching and an optoelectronic motion tracking system. The largest mean differences in relative pose between the two methods for any testing condition were 2.1°, 0.3°, and 1.1° in extension, abduction, and internal rotation respectively, and 1.3, 0.9, and 1.9mm in anterior, distal, and lateral translations, respectively. For the optimized position of the components during dynamic trials, the limits of agreement, between which 95% of differences can be expected to fall, were −2.9 to 4.5° in flexion, −0.9 to 1.5° in abduction, −2.4 to 2.1° in external rotation, −2.0 to 3.9mm in anterior-posterior translation, −2.2 to 0.4mm in distal-proximal translation and −7.2 to 8.6mm in medial–lateral translation. These mean accuracy values and limits of agreement can be used to determine whether the shape-matching approach using single-plane fluoroscopic images is sufficiently accurate for an intended motion tracking application.

Spread of ropivacaine by a weight‐based formula in a pediatric caudal block: a fluoroscopic examination

Caudal block is the most common regional technique to provide post-operative analgesia in pediatric infra-umbilical surgery. This study was designed to define how many spinal segments would be covered by the weight-based dosage of caudally administered 0.2% ropivacaine in children using the fluoroscopic method. After an approval from the institutional human research review board, in 83 ASA I boys undergoing day-case urological surgery, the distribution of ropivacaine mixed with a radioactive dye in relation to the volume injected caudally was studied. Three groups were studied: for perineal surgery 0.5 ml/kg (group C(0.5)), for inguinal hernia repair 1 ml/kg (group C(1.0)), and for orchiopexy 1.25 ml/kg (group C(1.25)). The dose of 0.2% ropivacaine containing radiopaque dye at a ratio of 1 : 4 was injected at a rate of 1 ml 3 s(-1). Fluoroscopic examination was performed immediately to define the level of the drug spread within the extradural space. The highest spinal levels [median with ranges] of spread were L2 [L4-T12] in group C(0.5), T12 [L1-T8] in group C(1.0), and T10 [L2-T7] in group C(1.25). Analysis by age distribution (infants: <12 months; toddlers: 12-36 months; and children: >36 months) revealed a larger spread in younger patients. Based on the fluoroscopic findings, the weight-based doses for caudally administered 0.2% bupivacaine suggested by Armitage are also useful for ropivacaine to block the spinal level required for the different types of surgeries studied.

Comparison of the Percutaneous Screw Placement Precision of Isocentric C-arm 3-dimensional Fluoroscopy-navigated Pedicle Screw Implantation and Conventional Fluoroscopy Method With Minimally Invasive Surgery

Retrospective clinical study to compare the percutaneous screw placement precision of isocentric C-arm (Iso-C) 3-dimensional fluoroscopy-navigated pedicle screw implantation and conventional fluoroscopy. The purpose of this study was to evaluate the accuracy of clinical percutaneous pedicle screw placement (PPSP) using Iso-C 3-dimensional fluoroscopy navigation. The technique of PPSP recently has been applied to internal fixation for segmental lumbar instability as a form of minimally invasive spine surgery. The percutaneous insertion technique requires surgical skill and experience. The 3-dimensional fluoroscopy-based image-guidance navigation system has been proven to be effective in guiding accurate PPSP in the lumbar area of cadavers. However, there have been few clinical reports comparing the accuracy of Iso-C 3-dimensional fluoroscopy-navigated pedicle screw implantation and the conventional fluoroscopy method. Here, 300 percutaneous pedicle screws were evaluated; half of them were inserted under Iso-C 3-dimensional navigation and the others under fluoroscopy. The accuracy of pedicle screw placement was examined postoperatively using an axial 2-mm slice computed tomography. Screw malpositioning was classified either as exposed screw (<50% of the screw outside the pedicle) or perforated pedicle (>50% of the screw outside the pedicle boundaries). Of the 150 pedicle screws placed with Iso-C 3-dimensional fluoroscopy-based image-guide assistance, 11 (7.3%) were classified as exposed screws and 0 (0%) as perforated pedicle. Of the 150 pedicle screws inserted under fluoroscopy, 18 (12%) were classified as exposed screw and 5 (3.3%) as perforated pedicle. The difference in frequency of screw misplacement between the procedure using Iso-C 3-dimensional fluoroscopy-based image-guide assistance and that using fluoroscopy was statistically significant (P<0.05; chi test). This study demonstrates the feasibility of placing percutaneous posterior lumbar pedicle screws with the assistance of Iso-C 3-dimensional navigation.

Intraoperative Fluoroscopy for Evaluation of Bony Resection During Arthroscopic Management of Femoroacetabular Impingement in the Supine Position

There is a steep learning curve regarding many aspects of arthroscopic management of femoroacetabular impingement. One of the concerns with regard to this approach is verification of appropriate bony resection for cam- and pincer-type pathology. Dynamic assessment and direct visualization of bony resection are the primary means of evaluating appropriate resection. Intraoperative fluoroscopy, however, can be a helpful adjunct when performing the rim resection or femoral resection osteoplasty. We describe a predictable and reproducible fluoroscopic method for performing and verifying appropriate bony resection of pincer and cam lesions in an attempt to help minimize the risk of under- and over-resection.

Electromagnetic navigation for percutaneous guide-wire insertion: Accuracy and efficiency compared to conventional fluoroscopic guidance

The combination of electromagnetic (EM) navigation with intraoperative fluoroscopic images has the potential to create the ideal environment for spinal surgical applications. This technology enhances standard intraoperative fluoroscopic information for localization of the pedicle entry point and trajectory and may be an effective alternative to other image-guided surgery (IGS) systems. This study was performed to assess the accuracy and time efficiency (placement and fluoroscopy) using EM navigation versus conventional fluoroscopy in the placement of pedicle guide-wires. Kirschner wire (K-wire) placement was performed in cadavers from T8 to S1 using EM navigation versus conventional fluoroscopy. Time for set-up, placement, and fluoroscopy was recorded. After insertion, the accuracy for each level was assessed for the presence and location of facet joint, pedicle, or vertebral cortical perforation using computed tomography imaging with multiplanar reconstructions. K-wire placements were 100% successful for both methods. Comparing EM-based IGS-assisted placement with the conventional fluoroscopy method showed a longer set-up time of 9.6 min versus 3.6 min, respectively. However, mean placement times of 6.3 min versus 9.7 min ( P = 0.005) and mean fluoroscopy times of 11 s versus 48 s ( P < 0.0001) were both shorter for the EM group. There were no significant differences in the proportion of pedicle, vertebral body, or facet joint breaches. A higher proportion of ideal trajectories was achieved in the EM group. Therefore, we have shown that an EM IGS system can assist the spine surgeon in minimally invasive pedicle screw insertion by providing high-accuracy K-wire placement with a significant reduction in fluoroscopy time.

Ultrasonography-Guided Percutaneous Nephrolithotomy

To evaluate the safety and efficacy of ultrasound-guided percutaneous nephrolithotomy (PCNL). Between August 2003 and December 2007, 47 patients were treated, 29 men and 18 women, with a mean age of 33.4 years (range 21-67 yrs) and a mean stone size of 31.5 mm (range 24-46 mm). All stones were located in the renal pelvis with mild to moderate hydronephrosis seen on intravenous urography. A ureteral stent was inserted cystoscopically, and saline was injected for more localization of the pelvicaliceal system (PCS), if needed. Puncture of the PCS was performed with an 18-gauge nephrostomy needle through the lower pole calyx, and all the stages, including dilatation, were performed under ultrasonography guidance. Thirty-nine patients were stone free in the kidneys, ureters, and bladder the day after the operation. Five patients had multiple fragments that measured about 4 to 5 mm, which passed in 4 weeks (total stone-free rate: 93.61%); failure occurred in two patients, and fluoroscopy was needed; two patients who had residual fragments that measured 10 and 12 mm underwent shockwave lithotripsy; and in one patient, a fragment that measured 7 to 8 mm migrated into the ureter--it fragmented and was removed with a ureteroscope 2 days after the operation. PCNL using sonography is a good alternative to the fluoroscopic method. It is performed without radiation exposure to the surgeon and patient; however, more experience is needed.

Abstract No. 263: New Fluoroscopic Method for Percutaneous Gastrostomy in an Animal Model and Clinical Practice

Abstract No. 263: New Fluoroscopic Method for Percutaneous Gastrostomy in an Animal Model and Clinical Practice

Navigated percutaneous placement of iliosacral screws using intra-operative three-dimensional imaging

To investigate the effect of a new technique of navigated percutaneous placement of iliosacral screws using intra-operative three-dimensional (3D) imaging. Sixteen patients with hip fracture were placed in supine position. After the reference marker was fixed on the iliac crest, a 3-D C-arm navigation system was used intra-operatively to obtain 3D images that were transferred to the navigation system by an automatic. Registration process to calculate the length of screw and direction to insert it. A navigated pointer defined the entry point, while navigated percutaneous drilling was done accordingly with a navigated drill bit in combination with a navigated drill sleeve under permanent dynamic control on the navigation screen without further intra-operative fluoroscopic imaging. A control intra-operative 3D scan was used to observe the position of the screws, while for didactic reasons another postoperative CT scan was done. Twenty screws were successfully inserted into the first sacral vertebral bodies of the 16 patients. No additional intra-operative and postoperative complications occurred. The average operation time was 80 minutes and the average intra-operative radiation time was 1.13 minutes. Four patients underwent bilateral iliosacral fixation with longer operation time (152 minutes) and radiation time (1.56 minutes). The post-operative 3D scanning showed good results. No screws penetrated into the sacral canal or foramen. The reduction of fracture or dislocation and the position of iliosacral screws were all judged satisfactory. Compared with the conventional fluoroscopy method, navigated percutaneous placement of iliosacral screws under intra-operative 3D imaging reduces the radiation time and improves the accuracy. It is feasible and useful though there are some disadvantages such as the inferior image quality compared to CT scan, prolonged operation time and higher overall cost.

Computertomographie-gesteuerte Gastrostomie, Jejunostomie und Gastrojejunostomie: Eine zuverlässige nicht-chirurgische Methode auch bei Kontraindikationen oder Scheitern der perkutanen endoskopischen Gastrostomie

To analyse retrospectively the results of CT (computed tomography)-guided gastrostomy or gastroenterostomy where an endoscopic procedure was not possible or had failed. Between August 1993 and March 1997, CT-guided gastrostomy (n = 50) or gastroenterostomy (n = 8) was performed in 58 patients (mean age 56 +/- 6 years; 51 males, 7 females). An endoscopic or fluoroscopic method had been contraindicated in 52 and had failed in 6 patients. Technical success was achieved in all patients. Three patients needed intravenous sedation. There were no procedure related complications requiring treatment. Three patients had a mild infection at the site of the skin puncture. CT-guided gastrostomy or gastroenterostomy is a safe and simple procedure which provides a minimally invasive alternative also in patients with contraindications to the established percutaneous method.

Reliability of a simple fluoroscopic method to study sagittal plane femorotibial contact changes in total knee arthroplasties during flexion

Clinical interest in sagittal plane kinematic analysis of the knee undergoing total knee replacement fosters the development of simple, reliable methods to estimate femorotibial contact in a regular clinical setting. In this study, the sagittal femorotibial contact was analysed in lateral X-rays and lateral fluoroscopic views, from extension to knee flexion. Quantitative and categorical data were obtained from these views by two different observers, and compared with data from direct views of the components. Interobserver and intermethod errors for quantitative and categorical data were evaluated based on correlation, kappa coefficient, and Bland–Altman graphs. Interobserver reproducibility of quantitative measurement from fluoroscopic views was r = 0.96 while categorical assignment exhibited a kappa coefficient of 0.95. Reproducibility from plain radiographs was not so high, with a kappa coefficient of 0.64. High concordance was also obtained when the method was compared with the direct view of the implant, supporting these measurement techniques. Bland–Altman graphs confirmed the absence of bias in the intermethod comparison. Therefore, with the obvious limitation of rotational assessment, lateral fluoroscopic evaluation enhanced by a simple fitting technique can be used as a valuable tool for clinical evaluation of knee kinematics in the sagittal plane.