Search

Background One potential benefit of the direct anterior approach (DAA) for total hip arthroplasty is the ability to use intraoperative fluoroscopy for acetabular cup positioning and limb-length evaluation. Previous studies comparing the use of fluoroscopy with an anterior approach to a posterior approach have reported conflicting results. To our knowledge, no prior study has compared acetabular cup position and limb-length discrepancy (LLD) using a DAA with and without fluoroscopy. Methods We retrospectively reviewed the charts of 298 patients who underwent direct anterior total hip arthroplasty with or without intraoperative fluoroscopy. All procedures were performed by 2 surgeons who use DAA as their primary approach. Preoperative and 6-week postoperative low anteroposterior pelvis and cross-table lateral radiographs were reviewed by 3 independent surgeons. Acetabular cup inclination, anteversion, and LLD were measured and compared. Results Thirty-three patients were excluded for inadequate imaging, leaving 125 patients in the fluoroscopy group and 140 patients in the nonfluoroscopy group. Mean inclination, anteversion, and LLD were 39.4° (95% confidence interval [CI], 38.5°-40.2°), 30.2° (95% CI, 29.2°-31.2°), and 1.1 mm (95% CI, 0.1 mm-2.2 mm) for the fluoroscopy group and 39.9° (95% CI, 39.3°-40.5°), 31.1° (95% CI, 30.0°-32.2°), and 0.8 mm (95% CI, −0.1 mm to 1.6 mm) for the nonfluoroscopy group. There was no significant difference in acetabular inclination (P = .35), anteversion (P = .22), or postoperative LLD (P = .64) between groups. Conclusion This study found no clinically or statistically significant difference in acetabular inclination, anteversion, or LLD between the fluoroscopy and nonfluoroscopy groups. Both surgeons achieved a similar mean acetabular cup position and an equivalent mean LLD.

For endovascular aortic repair (EVAR), integrating preoperative information of the aortic anatomy with intraoperative fluoroscopy can aid in reducing radiation exposure, contrast agent and procedure time. However, the quality of this fusion may deteriorate over the course of the intervention due to patient movement or deformation of the vasculature caused by interventional tools. Automatically detecting the instruments present in the X-ray image can help to assess the degree of deterioration, trigger automatic re-registration or aid in automatic workflow phase detection and process modeling. In this work, we investigate a flexible approach to segment different devices based on fully convolutional neural networks using multi-task learning. We evaluate the proposed approach on a set of 38 X-ray images acquired during EVAR interventions by targeting the segmentation of aortic stents, stiff guidewires and pigtail catheters. We compare the results to the performance of single-task networks. We manage to keep similar performance compared to single-task networks with Dice coefficients between 0.95 and 0.80 depending on the device, while speeding up computation by a factor of two.

Surgical extraction of a needle in an extremity can be difficult and humbling. If a needle is intra-articular, it should be treated like any other foreign body and be removed1. If it is extra-articular, the best option may be observation with serial radiographs, especially if the needle is stationary and asymptomatic. If the patient experiences pain from the needle, it can be surgically removed with intraoperative fluoroscopy on an elective basis. If a needle is not stationary, it may migrate to the skin surface, and then a needle holder can be used to pull it out. Magnet-assisted removal of ferrous foreign bodies previously has been described with various organ systems or the extremities, but, to the best of our knowledge, has not been used to remove an object from the foot2-10. Magnets are typically used to directly contact the ferrous-based object for immediate removal. We report the novel use of a magnet to …

Purpose To survey surgeons who perform a high volume of hip arthroscopy procedures regarding their operative technique, type of procedure, and postoperative management. Methods We conducted a cross-sectional survey of 27 high-volume orthopaedic surgeons specializing in hip arthroscopy to report their preferences and practices related to their operative practice and postoperative rehabilitation protocol. All participants completed the survey in person in an anonymous fashion during a meeting of the American Hip Institute. Results All surgeons perform hip arthroscopy with the patient in the supine position, accessing the central compartment of the hip initially, using intraoperative fluoroscopy. All surgeons perform labral repair (100%), with the majority performing labral reconstructions (77.8%) and gluteus medius repairs (81.5%). There is variability in the type of anchors used during labral repair. Most surgeons perform capsular closure in most cases (88.9%), inject either intra-articular cortisone or platelet-rich plasma at the conclusion of the procedure (59%), and prescribe a postoperative hip brace for some or all patients (59%). There is considerable variability in rehabilitation protocols. All surgeons routinely prescribe postoperative heterotopic ossification prophylaxis to their patients, with most surgeons (88.9%) prescribing a nonsteroidal anti-inflammatory medication for 3 weeks. Forty percent of the respondents use the modified Harris Hip Score as the most important outcome measure. Conclusions Consistent practices such as use of intraoperative fluoroscopy, heterotopic ossification prophylaxis, and labral repair skills were identified by surveying 27 hip arthroscopy surgeons at high-volume centers. Most of the surgeons performed routine capsular closure unless underlying conditions precluded capsular release or plication. The survey identified higher variability between surgeons regarding postoperative rehabilitation protocols and use of intra-articular pharmacologic injections at the end of the procedure. These data may provide surgeons with a set of aggregate trends that may help guide training, clinical practice, and research in the evolving field of hip arthroscopy.

Acetabular component malposition contributes to increased complications and early revision. Supine positioning during direct anterior approach (DAA) THA facilitates the use of fluoroscopy to improve component positioning. This study evaluated the accuracy of acetabular component orientation using intraoperative fluoroscopy in DAA THA. A total of 780 surgeries by two surgeons were retrospectively reviewed over a 3-year period. Ranges for abduction (30°–50°) and version (5°–250) were employed. Overall, 92% fell within the targeted abduction range, 93% fell within the targeted anteversion range, and 88% met both criteria. The accuracy of component positioning for combined abduction and anteversion improved yearly (79.2%, 2011; 90.9%, 2012; and 95.6%, 2013). Fluoroscopy in DAA THA is a useful tool to improve acetabular component orientation, though a learning curve exists with its interpretation.

Disorders of the spine are one of the oldest known human maladies, with descriptions found in ancient medical literature. As in many other areas of medicine, treatment of patients with these disorders has undergone rapid progress over the last century. Among treatment modalities, spinal instrumentation has been a significant technical advancement. Increased use of spinal instrumentation has spurred the need for accurate positioning of screws/instrumentation and enhanced stability of the construct. Traditionally, these have been placed using anatomic landmarks and intraoperative fluoroscopy. In patients with advanced degenerative disease or trauma, or in those with severe curvature deformity, anatomy can be of limited help. With intraoperative fluoroscopy, limited visualization can be a significant issue, especially in patients with a large body habitus. Image guidance, by providing live, accurate information for placement of instrumentation, significantly improves upon these issues. Image guidance has been used in neurologic surgery during recent decades. It was employed initially for intracranial applications, including treatment of brain disorders, with significant benefits and is now used routinely as an important adjunct tool in the operating room for intracranial neurologic surgery. Only more recently has image guidance been used in spine surgery.

Injuries of the Lisfranc’s joint are not so common, but in most of cases they are misdiagnosed. This have been changed by better diagnostic procedures, CT scan and MRI in some of the cases. The number of patients increases and this is of importance, due to the mentioned overlooked cases. The surgical treatment is preferable, either within few days or postponed for a7-10 days in aim to oedema subside. Intraoperative fluoroscopy is mandatory and stable fixation is better for the first three metatarsal bones, while the lateral two MT bones could be stabilized by Kirschner wires. Prolonged nonweight beairing is prescribed as well as physical therapy if one should obtain favorable outcome. [Projekat Ministarstva nauke Republike Srbije, br. 175095]

Tension band wiring with cerclage wiring is most widely used for treating displaced patellar fractures. Although wire breakage is not uncommon, migration of a fragment of the broken wire is rare, especially migration into the knee joint. We describe here a rare case of migration of a wire fragment into the posterior septum of the knee joint after fixation of a displaced patellar fracture with tension band wiring and cerclage wiring. Although it was difficult to determine whether the wire fragment was located within or outside the knee joint from the preoperative plain radiographs or three-dimensional computed tomography (3D CT), we found it arthroscopically through the posterior transseptal portal with assistance of intraoperative fluoroscopy. Surgeons who treat such cases should bear in mind the possibility that wire could be embedded in the posterior septum of the knee joint.

Background It is challenges for surgeon to position the distal locking screw of a tibia intramedullary nail. The traditional free-hand (FH) technique is related to the proficiency of surgeons and has a long learning curve. Furthermore, the radiation dose and the accuracy of screw placement should be taken into account. The new technology, the electromagnetic navigation system (ET), which is a radiation-free way to locate the position of the drill bit. The purpose of our study is to evaluate the results of the ET for distal locking screw of a tibia intramedullary nail and to compare the effects with the FH technique. Methods Eighty-nine cases of tibia diaphyseal fracture who needed to treat by intramedullary nails were analyzed retrospectively, and were divided into 2 groups. Patients in navigation group (n = 54) were treated with intramedullary nail using the ET for distal locking, while other 35 patients using FH technique. Intraoperative fluoroscopy exposure times, screw insertion times, and healing times were recorded. The parameter was used for comparison in 2 groups. Results The mean time of distal locking in the ET technique was significant less than that in the FH group (5.89 ± 2.02 minutes vs 12.26 ± 4.40 minutes) and the exposure time was reduced in ET group significantly (2.13 ± 0.73 seconds vs 19.09 ± 10.41 seconds). The healing time was proved to be coincident in FH group and ET group (15.34 ± 2.98w vs 16.06 ± 3.74w). The one-time success rate of distal locking nail operation was 100% in the navigation group, which was significantly higher than that in FH group (P Conclusion Compared with the FH technique, the ET for distal locking of tibia intramedullary nail has the advantages of high efficiency and short locking time without radiation.

Background Image-guided pedicle screw placement in the cervico-thoracic region is a commonly applied technique. In some patients with deformed cervico-thoracic segments, conventional or 3D fluoroscopy based registration of image-guidance might be difficult or impossible because of the anatomic/pathological conditions. Landmark based registration has been used as an alternative, mostly using separate registration of each vertebra. We here investigated a routine for landmark based registration of rigid spinal segments as single objects, using cranial image-guidance software. Methods Landmark based registration of image-guidance was performed using cranial navigation software. After surgical exposure of the spinous processes, lamina and facet joints and fixation of a reference marker array, up to 26 predefined landmarks were acquired using a pointer. All pedicle screws were implanted using image guidance alone. Following image-guided screw placement all patients underwent postoperative CT scanning. Screw positions as well as intraoperative and clinical parameters were retrospectively analyzed. Results Thirteen patients received 73 pedicle screws at levels C6 to Th8. Registration of spinal segments, using the cranial image-guidance succeeded in all cases. Pedicle perforations were observed in 11.0%, severe perforations of >2 mm occurred in 5.4%. One patient developed a transient C8 syndrome and had to be revised for deviation of the C7 pedicle screw. No other pedicle screw-related complications were observed. Conclusions In selected patients suffering from pathologies of the cervico-thoracic region, which impair intraoperative fluoroscopy or 3D C-arm imaging, landmark based registration of image-guidance using cranial software is a feasible, radiation-saving and a safe alternative.

The treatment of subtrochanteric fractures is a challenge for orthopaedic trauma surgeons. Three positions have been described previously: supine on a fracture table, supine on a flat radiolucent table, and the lateral decubitus position on a flat radiolucent table. Each one has its advantages and limitations. In this article we describe a prone position for intramedullary nailing of subtrochanteric femoral fractures. This position has the advantages including: 1) an easy approach to reduce and maintain the reduction of fracture by adjusting only the leg plate on injured side, 2) perfect intraoperation fluoroscopic imaging on both anteroposterior view and lateral view, and 3) an easy approach to establish an appropriate entry point even in obese patients.

Objective To discuss the significance and the short-term effect of bone puncture technique in transiliac approach to intervertebral endoscopic discectomy for the treatment of L5/S1 intervertebral disc herniation. Methods Nineteen patients were diagnosed as L5/S1 disc herniation and treated using transiliac approach to endoscopic discectomy (group I), and 20 patients were diagnosed as non-L5/S1 disc herniation and underwent conventional approach (group R). Leg pain was evaluated by VAS. MacNab ratings of the last follow-up were recorded to evaluate early clinical efficacy, and postoperative complications were recorded to evaluate surgical safety. The imaging changes of the patients 3 months after surgery were observed. Results One patient in group I, who felt abnormal in nerve roots, underwent symptomatic treatments, such as rehydration and hormone, and the abnormalities disappeared 3 days after treatment. There were no significant significances in operative time and intraoperative fluoroscopy times between groups I and R (p > 0.05), but there was a higher tendency in group I. The VAS scores of post-operation were significantly lower than that of pre-operation in the two groups (p 0.05). The MacNab score of the last follow-up showed excellent rate (95%) and good rate (90%) in groups I and R, respectively. Conclusions Bone puncture-combined transiliac approach to intervertebral endoscopic surgery could locate iliac puncture point individually, and establish a good iliac channel, which is safe, effective, and minimally invasive.

Introduction The purpose of this study was to compare acetabular cup position for 2 cohorts of total hip arthroplasty (THA) patients who had a direct anterior approach. Methods 100 THA cases were performed with an anterior approach using intraoperative fluoroscopy (IF) to aid in cup positioning. Another group of 100 cases underwent THA with an anterior approach without the use of any fluoroscopy. Postoperative abduction and anteversion angles were measured using Martell's hip analysis software. Results Mean abduction angle was 43.2° (standard deviation (SD) = 4.5°) for the IF group versus 37.5°(SD = 7.4°) for cases without IF (pConclusions There was significantly less variation in cup position among the cases using IF with regards to abduction.

Background Acetabular cup placement in total hip arthroplasty (THA) has been recognized as an important factor in operative success, and accurate cup placement has been the impetus for novel medical technologies. Methods This article examines the cup placement in 955 THAs using a freehand Direct Anterior Approach on a standard operating table. Acetabular anteversion and inclination were determined using the circle theorem. Measurements were divided into safe zone placement determined by Callanan et al as 5°-25° for anteversion and 30°-45° for inclination, as well as by Lewinnek et al as 5°-25° for anteversion and 30°-50° for inclination. Dislocation rate was determined and correlated to safe zone placement. Results Although technology has advanced for cup placement, this investigation shows that a freehand technique demonstrates 0.31% dislocation after THA with an accuracy of 85% for the Lewinnek safe zone and 61% for Callanan, potentially because of the sparing of the posterior hip capsule. Conclusion The direct anterior approach to the hip on a regular operating table is safe and reliable. Our results demonstrate improvement in cup positioning compared with other freehand techniques. Surgeon awareness and control of the position of the pelvis within space optimizes acetabular component accuracy and precision without the need for special equipment, such as intraoperative fluoroscopy.

Restoration of biomechanics is a major goal in THA. Imageless navigation enables intraoperative control of leg length equalization and offset reconstruction. However, the effect of navigation compared with intraoperative fluoroscopy is unclear.We asked whether intraoperative use of imageless navigation (1) improves the relative accuracy of leg length and global and femoral offset restoration; (2) increases the absolute precision of leg length and global and femoral offset equalization; and (3) reduces outliers in a reconstruction zone of ± 5 mm for leg length and global and femoral offset restoration compared with intraoperative fluoroscopy during minimally invasive (MIS) THA with the patient in a lateral decubitus position.In this prospective study a consecutive series of 125 patients were randomized to either navigation-guided or fluoroscopy-controlled THA using sealed, opaque envelopes. All patients received the same cementless prosthetic components through an anterolateral MIS approach while they were in a lateral decubitus position. Leg length, global or total offset (representing the combination of femoral and acetabular offset), and femoral offset differences were restored using either navigation or fluoroscopy. Postoperatively, residual leg length and global and femoral offset discrepancies were analyzed on magnification-corrected radiographs of the pelvis by an independent and blinded examiner using digital planning software. Accuracy was defined as the relative postoperative difference between the surgically treated and the unaffected contralateral side for leg length and offset, respectively; precision was defined as the absolute postoperative deviation of leg length and global and femoral offset regardless of lengthening or shortening of leg length and offset throughout the THA. All analyses were performed per intention-to-treat.Analyzing the relative accuracy of leg length restoration we found a mean difference of 0.2 mm (95% CI, -1.0 to +1.4 mm; p = 0.729) between fluoroscopy and navigation, 0.2 mm (95 % CI, -0.9 to +1.3 mm; p = 0.740) for global offset and 1.7 mm (95 % CI, +0.4 to +2.9 mm; p = 0.008) for femoral offset. For the absolute precision of leg length and global and femoral offset equalization, there was a mean difference of 1.7 ± 0.3 mm (p0.001) between fluoroscopy and navigation. The biomechanical reconstruction with a residual leg length and global and femoral offset discrepancy less than 5 mm and less than 8 mm, respectively, succeeded in 93% and 98%, respectively, in the navigation group and in 54% and 95%, respectively, in the fluoroscopy group.Intraoperative fluoroscopy and imageless navigation seem equivalent in accuracy and precision to reconstruct leg length and global and femoral offset during MIS THA with the patient in the lateral decubitus position.

We retrospectively analyzed a total of 1,218 pedicle screws for accuracy, with postoperative computed tomography (CT), in 198 patients who were operated on between March 2004 and September 2012.To determine the incidence of screw misplacement in patients who received a transpedicular screw fixation, with intraoperative fluoroscopy in the lateral and lateral with anteroposterior (AP) positions. The results are compared between the two groups.Retrospective comparative study of accuracy of pedicle screw placement in thoracic and lumbar spine.The sample consists of 198 consecutive patients who underwent transpedicular screw fixation.Accuracy of screw placement was evaluated by postoperative CT scan. Misplacement was defined in cases where more than 25% of the screw size was residing outside the pedicle.The indications for hardware placement, radiologic studies, patient demographics, and reoperation rates were recorded. Five hundred twenty-eight screws (Group A, n=81) were inserted into the vertebral body with the assistance of lateral fluoroscopy only, whereas 690 screws (Group B, n=117) were inserted with the assistance of lateral fluoroscopy, and the final positions of the screws were checked with AP fluoroscopy.A total of 1,218 screws were analyzed, with 962 screws placed at the lumbosacral region and 256 screws at the thoracic region. According to the postoperative CT scan, 27 screws (2.2%) were identified as breaching the pedicle. Nineteen of them (3.6%) were in Group A, whereas 8 (1.16%) were in Group B. The rate of pedicle breaches was significantly different between Group A and B (p=.0052). In Group A, the lateral violation of the pedicle was seen in 10 screws (1.9%), whereas medial violation was seen in 9 screws (1.7%). In Group B, the lateral violation of the pedicle was seen in six screws (0.87%), whereas medial violation was seen in two screws (0.29%). The medial and lateral penetration of screws were significantly different between Groups A and B (p.05). A pedicle breach occurred in 21 patients, and 15 of them underwent a revision surgery to correct the misplaced screw. Of these patients, 11 (13.6%) were in Group A, and 4 (3.4%) were in Group B (p=.0335).In this study, we evaluated and clarified the diagnostic value of intraoperative fluoroscopy in both the lateral and AP imaging that have not yet been evaluated in any comparative study. We concluded that the intraoperative use of fluoroscopy, especially in the AP position, significantly decreases the risk of screw misplacement and the results are comparable with other advanced techniques.

Background Central screw positioning in the scaphoid provides biomechanical advantages. Methods A prospective randomized study of six fluoroscopically guided and six electromagnetically navigated screw (ENS) placements was performed on human cadavers. Accuracy of screw position was determined. Intraoperative fluoroscopy exposure times, readjustments of drilling directions, complete restarts and complications were documented. Results The ENS method provided a mean time benefit of 7.34 min compared with the standard method and the mean screw length ratio (SLR coronar: ENS 0.96 ± 0.04 mm, SFF: 0.92 ± 0.04 mm, P = 0.065; SLR sagittal: ENS 0.98 ± 0.02 mm, SFF: 0.91 ± 0.04 mm, P = 0.009) and the screw axis deviation angle (AD coronar: ENS 3.33 ± 2.34°, SFF: 10.33 ± 2.58°, P = 0.002; AD sagittal: ENS 2.83 ± 0.98°, SFF: 11.00 ± 6.16°, P = 0.002) were lower. Using the electromagnetic navigation procedure no drilling readjustments or restarts were required, no cortical breach occurred. Conclusions Compared with the standard fluoroscopic technique, the ENS method used in this study showed higher accuracy, less complications, required less operation and radiation exposure time. Copyright © 2014 John Wiley & Sons, Ltd.

Rotational malalignment after intramedullary (IM) nailing of femoral fractures remains a significant problem. A technique using intraoperative fluoroscopy and the anteversion inherent to the IM nail for obtaining appropriate femoral rotational alignment is presented. The technique is advocated as a simple alternative to more complex methods for estimation of femoral anteversion during placement of femoral IM nails. This method is simple and requires intraoperative fluoroscopy on the injured extremity alone. It reliably sets the femoral anteversion within a normal physiologic range with minimal additional intraoperative steps and without preoperative measurements.

Introduction Properly placed tibial and femoral tunnels in anterior cruciate ligament (ACL) reconstruction are important because tunnel misplacement can cause abnormal changes in graft tension patterns, resulting in postoperative knee laxity. To overcome the inaccuracy of tunnel position in ACL reconstruction, intraoperative fluoroscopy has been proven to be a useful method in previous studies focusing on the tunnel position in single-bundle reconstruction, but few studies are available on the efficacy and necessity of intraoperative fluoroscopy for double-bundle (DB) reconstruction. The purpose of this prospective randomized case-control study was to evaluate the effect of intraoperative fluoroscopy on femoral and tibial tunnel position in anatomic DB ACL reconstruction using a postoperative tunnel position in a three-dimensional computed tomography (3D-CT). Hypothesis Intraoperative fluoroscopy during ACL DB reconstruction could make an appropriate tunnel position closer to the anatomical center compared to conventional fluoroscopy-free procedure. Material and methods Sixty patients undergoing ACL DB reconstruction (30 fluoroscopy-free reconstruction group and 30 in fluoroscopy-assisted reconstruction group) were included in this prospective study, and randomly allocated into two groups. Mean values of the percentage distance of femoral and tibial tunnel center in a 3D-CT were compared between the two groups. Knee laxity (the anterior translation and pivot-shift grade) and clinical outcomes were also compared at the last follow-up. Results There was a significant difference only in femoral anteromedial (AM) bundle tunnel position, but not in femoral posterolateral (PL) bundle, tibial AM, or PL bundle tunnel position between the two groups. Femoral AM bundle tunnel in the fluoroscopy-assisted reconstruction group showed significantly (p = 0.005) deeper position compared to that in the fluoroscopy-free reconstruction group. There was no significant difference in anterior translation, pivot-shift grade, or clinical outcomes between the two groups. Discussion Fluoroscopy-assisted ACL DB reconstruction can make deeper placement of the femoral AM bundle than the conventional ACL DB reconstruction. Level of evidence II, prospective randomized controlled trial.

Background: The aim of this work was to assess whether stone complexity with the Guy’s stone score (GSS) is associated with increased intraoperative fluoroscopy time. Methods: We retrospectively reviewed records of 261 consecutive patients undergoing percutaneous nephrolithotomy between 2007 and 2015. Of these, 203 had both preoperative computed tomography for accurate staging and full intraoperative fluoroscopy and radiation dosimetry data were available. Stone complexity was assessed using GSS. A correlation between fluoroscopy time (FT) and GSS was assessed in a univariate and multivariate fashion, including parameters such as age, sex, body mass index (BMI), and number of accesses. Results: The overall mean FT was 3.69 min [standard deviation (SD) 2.77]. The overall mean Guy’s score was 2.5 (SD 1). There was a statistically significant correlation between operative time and FT ( r = 0.34, p < 0.0001). There was a trend towards increasing operative time with increasing GSS ( r = 0.12, p = 0.08), but there was no statistically significant correlation. There was no correlation between FT and GSS ( r = 0.04, p = 0.55). On multivariable regression, accounting for sex, BMI, age, and singular versus multiple accesses, there was no significant correlation between stone complexity and FT ( p = 0.893). Conclusions: In the setting of conscious efforts to reduce intraoperative radiation exposure, increasing stone complexity, as classified by GSS, did not correlate with FT on univariate or multivariate analysis. Thus, treatment of more complex stones may be undertaken without concern that there is an inevitable need for significantly increased fluoroscopy exposure to the patient or operating room staff.

In this article, we describe a method for computer-assisted distal radius osteotomies in which computer-generated, patient-specific plastic guides are used for intraoperative guidance. Before surgery, the correction and plate location are planned using computed tomography scans for both radii and ulnae, and the planned locations of the distal and proximal drill holes for the plate are saved. A plastic, patient-specific instrument guide is created using a rapid prototyping machine into which a mirror image of intraoperative, accessible bone structure of the distal radius is integrated. This allows for unique positioning of the guide during surgery. For each planned drill location, a guidance hole is incorporated into the guide. During surgery, a conventional incision is made, and the guide is positioned on the radius. The surgeon drills the holes for the plate screws into the intact radius and performs the osteotomy using the conventional technique. Using the predrilled holes, the surgeon affixes the plate to the radius fragments. The guides are easy to integrate into the surgical workflow and minimize the need for intraoperative fluoroscopy for guidance of the procedure.

To assess the utility of the dorsal tangential view (DTV) in detecting intraoperative dorsal screw penetration in distal radius fractures treated with volar locked plating.Retrospective cohort study.Academic level 1 trauma center.Skeletally mature patients where open reduction internal fixation with volar locked plating was the definitive treatment. A total of twenty-six patients were evaluated.Intraoperative anteroposterior, lateral, 20 degree tilted lateral, and DTVs were obtained through fluoroscopy in all wrists. Screw exchange and position by fluoroscopic view was recorded. A computed tomography (CT) was taken postoperatively to identify residual prominent screws.Data points included frequency of screw exchange by standard fluoroscopic views, the DTV, and residual prominent screws detected by CT.Eight constructs of thirty (27%) had prominent screws evident on the DTV but not seen on standard fluoroscopic analysis. CT identified 5 additional screws with ≥1 mm dorsal penetration not identified by the DTV. All except 1 screw was in the second dorsal wrist compartment. The DTV was 67% sensitive with a negative predictive value of 97%.It is risky and unnecessary to place bicortical screws in the distal part of a volar plate. Given that the DTV view was not sufficient to avoid dorsal screw prominence, distal screws should be intentionally 2-4 mm shorter than measured. Recent studies propose bicortical distal locking screws are not needed for sufficient construct stiffness in volar locked plating. We suggest caution when using this view to verify acceptable placement of screws in proximity to the second dorsal compartment.Diagnostic level III. See Instructions for Authors for a complete description of levels of evidence.

Exposure to ionizing radiation in the operating room is governed by practical prevention and protection measures on the international, national and local levels. We evaluated the equivalent dose to the hand of an orthopedic surgeon over 13 months. An orthopedic surgeon wore a ring dosimeter on the ring finger of his right hand for all surgical procedures requiring intraoperative fluoroscopy between March 2014 and April 2015. Monthly doses were evaluated by the IRSN over the study period. The number and type of procedures were compiled as well as the type of fluoroscopy unit used. Four hundred procedures were performed during this period, including 182 with fluoroscopy. The equivalent cumulative dose at the hand was 4,75 mSv. No correlation was found with the type of procedure or type of fluoroscopy unit (conventional or mini C-arm). Equivalent doses were below the annual regulatory limit in France of 500 mSv. These results are consistent with those reported in the literature. However, recent studies have noted that both younger surgeons in training and more experienced surgeons must remember to use radiation protection measures.

The use of intraoperative fluoroscopy has become a routine and useful adjunct within orthopaedic surgery. However, the fluoroscopy machine may become an additional source of contamination in the operating room, particularly when maneuvering from the anterior-posterior position to the lateral position. Consequently, draping techniques were developed to maintain sterility of the operative field and surgeon. Despite a variety of methods, no studies exist to compare the sterility of these techniques specifically when the fluoroscopy machine is in the lateral imaging position. We evaluated the sterility of 3 c-arm draping techniques in a simulated operative environment. The 3 techniques consisted of a traditional 3-quarter sterile sheet attached to the side of the operative table, a modified clip-drape method, and a commercially available sterile pouch. Our study demonstrated that the traditional method poses a high risk for sterile field contamination, whereas the modified clip-drape method and commercially available sterile pouch kept floor contamination furthest from the surgical field. With the current data, we urge surgeons to use modified techniques rather than the traditional draping method.

OBJECTIVE Lateral lumbar interbody fusion (LLIF) is an increasingly popular technique used to treat degenerative lumbar disease. The technique of using an intraoperative cone-beam CT (iCBCT) and an image-guided navigation system (IGNS) for LLIF cage placement has been previously described. However, other than a small feasibility study, there has been no clinical study evaluating its accuracy or safety. Therefore, the purpose of this study was to evaluate the accuracy and safety of image-guided spinal navigation in LLIF. METHODS An analysis of a prospectively acquired database was performed. Thirty-one consecutive patients were identified. Accuracy was initially determined by comparison of the planned trajectory of the IGNS with post–cage placement intraoperative fluoroscopy. Accuracy was subsequently confirmed by postprocedural CT and/or radiography. Cage placement was graded based on a previously described system separating the disc space into quarters. RESULTS The mean patient age was 63.9 years. A total of 66 spinal levels were treated, with a mean of 2.1 levels (range 1–4) treated per patient. Cage placement was noted to be accurate using IGNS in each case, as confirmed with intraoperative fluoroscopy and postoperative imaging. Sixty-four (97%) cages were placed within Quarters 1 to 2 or 2 to 3, indicating placement of the cage in the anterior or middle portions of the disc space. There were no instances of misguidance by IGNS. There was 1 significant approach-related complication (psoas muscle abscess) that required intervention, and 8 patients with transient, mild thigh paresthesias or weakness. CONCLUSIONS LLIF can be safely and accurately performed utilizing iCBCT and IGNS. Accuracy is acceptable for multilevel procedures.

Arthrodesis of the sacroiliac joint (SIJ) for surgical treatment of SIJ dysfunction has regained interest among spine specialists. Current techniques described in the literature most often utilize intraoperative fluoroscopy to aid in implant placement; however, image guidance for SIJ fusion may allow for minimally invasive percutaneous instrumentation with more precise implant placement. In the following cases, we performed percutaneous stereotactic navigated sacroiliac instrumentation using O-arm® multidimensional surgical imaging with StealthStation® navigation (Medtronic, Inc. Minneapolis, MN). Patients were positioned prone and an image-guidance reference frame was placed contralateral to the surgical site. O-arm® integrated with StealthStation® allowed immediate auto-registration. The skin incision was planned with an image-guidance probe. An image-guided awl, drill and tap were utilized to choose a starting point and trajectory. Threaded titanium cage(s) packed with autograft and/or allograft were then placed. O-arm® image-guidance allowed for implant placement in the SIJ with a small skin incision. However, we could not track the cage depth position with our current system, and in one patient, the SIJ cage had to be revised secondary to the anterior breach of sacrum.

Replacement of the fractured humeral head with a modular prosthesis. The procedure aims at an adequate reconstruction of shape and function of the shoulder. Displaced three- and four-part fractures of the proximal humerus that cannot be reduced and internally fixed. Fracture can be reduced and adequately internally fixated. Noncompliant patient. In beach-chair position, the fractured humeral head is removed via a deltopectoral approach. The Aequalis modular fracture prosthesis can be positioned by two methods: (i) a fracture jig optimizing height and retroversion of the prosthesis, (ii) under additional intraoperative fluoroscopy. Healing of the tuberosities can be promoted by cancellous grafts taken from the fractured head. These are fixed by four heavy sutures running horizontally and two sutures running vertically. 13 out of 22 patients treated by primary hemiarthroplasty (within 10 days after the fracture) and 34 out of 50 patients treated by secondary arthroplasty could be assessed after a mean follow-up of 40 (15–70) and 44 (8–98) months, respectively. The absolute Constant score amounted to 45 and 50 points, respectively, and the relative score to 56% in both groups. The majority of patients was free of pain or suffered less pain than before the operation (secondary arthroplasty; p < 0.001). In contrast to these, only satisfactory, objective results, self-assessment was good or better than before (secondary prostheses; p < 0.001). In both groups, prognostic factors were the size and position of the tuberosities (p < 0.001).

A 34-year-old man sustained a closed right tibial plateau fracture as the passenger in a golf cart rollover accident. He was transferred from an outside hospital and evaluated in the emergency room 6 h after injury. At the time, his leg compartments were but compressible, with normal distal sensation and pulses, and no pain with passive stretch.

Purpose 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. Methods 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. Results 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. Conclusions 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. Clinical Relevance The novel method considerably improves on the standard operating procedure in terms of safety, operation time, and radiation exposure.

Background: The use of intraoperative fluoroscopy in orthopedic surgery involves frequent exposure to ionizing radiation in the operating room. Although a number of studies have found radiation exposure to orthopedic surgeons to be well below recommended doses, the long-term effects of low-dose radiation are not well known. Thus, all effective practical methods should be undertaken to reduce the exposure to radiation. Our purpose was to determine whether the use of a laser-aiming device improves the accuracy of intraoperative fluoroscopy to reduce, by implication, radiation exposure in the operating room. Methods: From March to October 2004, there were 92 consecutive cases requiring use of fluoroscopy in the orthopedic foot and ankle service of the authors’ institution. The number of accurate and inaccurate images with or without the presence of a radiology technician and a laser-aiming device were compared. Results: The accuracy of imaging with the laser-aiming device was higher than the imaging without the device ( p < 0.001). The accuracy of the images obtained by the surgeon was higher than the technicians’ images when laser guidance was used ( p = 0.027). There was no significant difference between the images obtained by the surgeon or the technicians when the aiming device was not used ( p = 0.09). Conclusion: The use of a laser-aiming device to help position during fluoroscopy is recommended in an effort to reduce radiation exposure in foot and ankle surgery.

Object The accurate intraoperative localization of the correct thoracic spine level remains a challenging problem in both open and minimally invasive spine surgery. The authors describe a technique of using preoperatively placed percutaneous fiducial screws to localize the area of interest in the thoracic spine, and they assess the safety and efficacy of the technique. Methods To avoid wrong-level surgery in the thoracic spine, the authors preoperatively placed a percutaneous 5-mm fiducial screw at the level of intended surgery using CT guidance. Plain radiographs and CT images with reconstructed views can then be referenced in the operating room to verify the surgical level, and the fiducial screw is easily identified on intraoperative fluoroscopy. The authors compared a group of 26 patients who underwent preoperative (often outpatient) fiducial screw placement prior to open or minimally invasive thoracic spine surgery to a historical group of 26 patients who had intraoperative localization with fluoroscopy alone. Results In the treatment group of 26 patients, no complications related to fiducial screw placement occurred, and there was no incidence of wrong-level surgery. In comparison, there were no wrong-level surgeries in the historical cohort of 26 patients who underwent mini-open or open thoracic spine surgery without placement of a fiducial screw. However, the authors found that the intraoperative localization fluoroscopy time was greatly reduced when a fiducial screw localization technique was employed. Conclusions The aforementioned technique for intraoperative localization is safe, efficient, and accurate for identifying the target level in thoracic spine exposures. The fiducial marker screw can be placed using CT guidance on an outpatient basis. There is a reduction in the amount of intraoperative fluoroscopy time needed for localization in the fiducial screw group.

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.

Thoracic pedicle screw fixation techniques are still controversial for thoracic deformities because of possible complications including neurologic deficit. Methods to aid the surgeon in appropriate screw placement have included the use of intraoperative fluoroscopy and/or radiography as well as image-guided techniques. We describe our technique for free hand pedicle screw placement in the thoracic spine without any radiographic guidance and present the results of pedicle screw placement analyzed by computed tomographic scan in two human cadavers. This free hand technique of thoracic pedicle screw placement performed in a step-wise, consistent, and compulsive manner is an accurate, reliable, and safe method of insertion to treat a variety of spinal disorders, including spinal deformity.

The direct anterior approach for total hip arthroplasty (THA) requires the use of intraoperative imaging, exposing the patient and surgical team to radiation. The authors hypothesized that calculation of the preoperative pelvic tilt angle and communication of this value with the fluoroscopy technician may result in a decrease in intraoperative fluoroscopy use. The study also examined total radiation exposure during the procedure to ensure that it was within safe limits. The pelvic tilt was calculated preoperatively for 100 consecutive patients undergoing THA by the direct anterior approach. The fluoroscopy technician was blinded to the value of pelvic tilt for the first 50 cases (control group), with the angle being communicated for the following 50 cases (test group). The total duration of fluoroscopy use for each case was recorded. The values were compared for the 2 experienced technicians involved in the study. The surgeon was blinded to the duration of fluoroscopy use in all cases. Mean fluoroscopy time was 28.65 seconds in the control group and 23.61 seconds in the test group ( P =.033). No significant difference in duration of fluoroscopy use was found between the 2 fluoroscopy technicians. The control group and the test group were within safe limits of radiation exposure to both the patient and the surgical team. Preoperative pelvic tilt calculation significantly decreases the amount of imaging used during THA by the direct anterior approach. Although it was a statistically significant reduction, both groups were within safe limits for both the surgical team and the patients, and thus the clinical significance is unknown. [ Orthopedics. 2016; 39(5):e962–e966.]

Background Selecting a properly sized radial head prosthesis is imperative during radial head replacement. Although there has been much emphasis on avoiding overlengthening of the radius, little has been studied about how to avoid shortening. The purpose of this study was to characterize how a radial head replacement appears on intraoperative fluoroscopy depending on the height of the prosthetic radial head. Methods Articular cartilage thickness of the radial head was measured in 9 cadaveric elbows. Radial head replacement was performed in each specimen with 4 different prosthetic head heights: 4 mm and 2 mm shortening, anatomic, and 2 mm overlengthening. Anteroposterior fluoroscopic images were obtained for each head height, and the prosthetic radial head height was measured at 3 forearm positions (supination, neutral, and pronation) using the subchondral bone of the lateral edge of the coronoid at the reference point. Results The mean cartilage thickness of the radial head was 1.3 ± 0.4 mm. The prosthetic radial head appeared 2.2 ± 0.4 mm more proximal than the subchondral bone of the coronoid lateral edge in anteroposterior radiographs when the articular surface of the prosthesis was completely even with the coronoid articular surface. Unlike the native radial head, a prosthetic radial head showed a significant change of height with different forearm rotation ( P Discussion This study found that a perfectly anatomic radial head replacement appears overlengthened by approximately 2 mm in intraoperative radiographs. This finding can be useful in guiding the appropriate height of a prosthetic radial head.

Recent studies have demonstrated deleterious effects of ionizing radiation from diagnostic and therapeutic imaging procedures. One of the barriers to minimizing patient exposure is physician awareness. We prospectively studied whether providing surgeons with feedback on their fluoroscopy utilization would affect intraoperative fluoroscopy times.In 2007, we prospectively began to track fluoroscopy usage for all urology cases. Nine months later, surgeons started to receive periodic reports with their mean fluoroscopy time compared with their peers. We reviewed all ureteroscopic cases for nephrolithiasis from the date tracking began (2006-2010, n = 311). Using the initial 9-month period as a control, we studied the effect of providing feedback on mean fluoroscopy times in subsequent periods and analyzed patient factors that may affect radiation exposure.Mean fluoroscopy times for unilateral ureteroscopy decreased by 24% after surgeons received feedback (2.74-2.08 minutes, p = 0.002). On multivariate analysis, factors that independently predicted decreased fluoroscopy times included female sex (p = 0.02), stones in the distal ureter (p = 0.04), and if the surgeon had received feedback (p = 0.0004). Factors that increased fluoroscopy times included the presence of hydronephrosis (p = 0.001), use of a ureteral access sheath (p = 0.04), ureteral balloon dilation (p = 0.0001), and placement of a postoperative stent (p = 0.002).Providing surgeons with feedback on their fluoroscopy usage reduces patient and surgeon radiation exposure. Implementing such a tracking system requires minimal changes to existing operating room staff workflow. Further study is warranted to study the impact of this program on other procedures that utilize fluoroscopy in urology and other specialties.

To evaluate the utility of performing endonasal transsphenoidal pituitary surgery with computer-based neuronavigation, and to examine the efficacy of computer-based neuronavigation compared to fluoroscopy.We conducted a retrospective review of patients who underwent pituitary surgery between September 1998 and September 2008. Of 120 consecutive patients, 70 met inclusion criteria and were fully examined. The inclusion criteria were that patients had undergone endonasal transsphenoidal pituitary surgery performed by the same neurosurgeon at the same institution. Nineteen of the patients were treated using intraoperative fluoroscopy and 48 were treated using the BrainLAB VectorVision neuronavigation system. Preparation times, surgical times and associated complications were analyzed.Our results indicate that image guidance reduces the overall operating room time and complication rate. Average preparation time for fluoroscopy and computer-based neuronavigation was 70.3 and 67.3 min, respectively (p = 0.3299). Average surgical time with fluoroscopy and BrainLAB was 131 and 107.9 min, respectively (p = 0.0079). The results were also analyzed with regard to other parameters such as associated complications, age and diagnoses.Computer guided endoscopic endonasal transsphenoidal surgery provides a three-dimensional image to the surgeon, allowing for greater visual accuracy and surgical precision and a faster procedure without radiation exposure or the need for additional personnel.

Study design Applying rotating rod techniques to reduce irreducible atlantoaxial dislocation. Objective To spare the occipital-C1 motion by the strategy in reduction of before surgery irreducible atlantoaxial dislocation with obvious neurologic symptoms and congenital odontoid aplasia. Summary of background data The treatment of atlantoaxial dislocation (AAD) is a challenging problem for most surgeons. Posterior surgical stabilization of C1 and C2 include C1-C2 transarticular screws, or C1 lateral with C2 pars screws. These constructs, however, are based on preoperative reductions. When preoperative skull reduction fails and myelopathic symptoms coexist, long-segment cervico-occipital fusion and decompression are usually the only practical choice. Methods The authors explored a different surgical technique to spare the axial occipital joints by rotating rods in polyaxial C1, C3 lateral mass, and C2 pars screws, functioning as a lever analogue. Three before surgery irreducible AAD cases with obvious neurologic symptoms and congenital odontoid aplasia were successfully reduced and fused with this procedure. The authors used intraoperative somatosensory-evoked potential monitoring and intraoperative fluoroscopy. Preoperative skull traction was employed to distract and help extend the atlantoaxial complexes. Results Three C1-C2 dislocations were reduced completely without any deterioration of neurologic signs. Cervical myelopathic symptoms recovered soon after the operation. No atlantoaxial subluxation recurred. They returned to their normal work and/or activities. Conclusion The rotating rod strategy is a viable option to reduce and fuse C1-C3 for AAD with odontoid aplasia. It spares the occipital-C1 motion.

Introduction The placement of thoracic pedicle screw is technically difficult, and the medial mal position can result in a feared risk for the spinal cord. The effectiveness of detecting mal-positioning of pedicle screws varies widely in the literature, specially at thoracic levels, but in 2014, Calancie et al. described a technique with high accuracy in preventing that in adult patients. We prospectively studied the usefulness of the technique in adolescents with idiopathic scoliosis. Methods We studied 51 adolescent patients (41 female), mean age of 14.8 y (11–18 y) diagnosed with idiopathic scoliosis, submitted to scoliosis correction with the free-hand technique for thoracic pedicle screw placement under total intravenous anesthesia (TIVA) and intraoperative neuromonitoring (IONM) with our standard protocol updated with the multi-train stimulation technique (MTST). MTST parameters consists of a repetitive train of electric pulses applied in the track and in the implanted pedicle screw. The warning criteria was a muscle MEP recorded in lower limb muscles with stimulus below 12 mA for the track and 25 mA for the screw. Intraoperative fluoroscopy was used to check screw position if the warning criteria was achieved and after the placement of all screws if there were no alarms. The final decision of the surgeon to a given alarm considered anatomical features, the threshold and the fluoroscopy images. Results We studied 210 tracks/screws from T2 to L1 in the first 13 cases and 390 from T2 to T10 in the remaining 38. Track/screw threshold was below the limit 49 times (8.2%), with higher incidence for T5 and T9 (10 times each), and for T7 and T8 (8 times each). Tracks/screws were redirected successfully in 33 cases and due to their persistent lower thresholds, withdrawn in 8, all of them from the apex of the scoliosis concavity. In the remaining 8 cases the surgeon decided to let the implant in the original position considering the imaged and the screw thresholds close to the limit. In 24 cases (47%) the warning criteria were not achieved neither for track or screw, and the images agreed with the IONM findings. In 3 cases the thresholds for the screws were below 4 mA and a complete loss of TcMEP in lower limb immediately followed the screw placement. In two cases the screws were removed immediately, and the patients have transitory motor deficit, but in one case the surgeon took a long time to remove the implants and the patient become paraplegic. MTST takes no more than 10 s for each screw. Conclusion The technique showed a good relationship with medial mal-positioning of the track/screw. It was not time consuming and the surgeons felt confident with the warning criteria, reducing also the X-ray exposition. Very low thresholds can even suggest spinal cord lesion demanding the cross checking with TcMEP. The technique showed to be safe and trustful for younger patients (adolescents) with idiopathic scoliosis and should be considered a standard of care for thoracic pedicle screw placement.

Arthroscopic femoral osteoplasties might be technically demanding, might cause prolonged operative times and restrict the intraoperative overview. An automated navigated matching process of preoperative CT-data and intraoperative fluoroscopy should allow for noninvasive registration for FAI-surgery.Six hip joints were used with a conventional navigation system. Defined osseous lesion (2 × 2 mm) in the femoral neck, head neck junction, and head region were created followed by automated segmentation including CT-fluoro image fusion by the navigation system. Precision of registration process was tested trough a lateral arthroscopic portal. In vivo distances between pointer tip to bone were measured. Secondary in vivo distances between an inserted navigated shaver and the osseous lesions were measured.Our results allow a CT-fluoroscopy matching procedure for noninvasive registration process for navigated FAI-surgery in multiplanar planes. Precision is more accurate at the femoral neck and head-neck junction than at the femoral head area.Future navigated applications might simplify and increase precision of FAI-surgery.

STUDY DESIGN A retrospective radiographic analysis. PURPOSE To estimate the accurate trajectory in the axial plane for iliac screw insertion in 200 Korean patients using radiographic images. OVERVIEW OF LITERATURE Several complications have been encountered after fusion to the lumbosacral junction, including pseudarthrosis, S1 screw loosening, and sacral fractures. Iliac screw fixation is considered an efficient method for augmenting sacral screw fixation but there are few reports on the trajectory of iliac screw insertion. The trajectory in the sagittal plane can be visualized by intraoperative fluoroscopy. However, there is no method to check the accuracy of the trajectory in the axial plane during surgery. METHODS Between January 2007 and February 2009, 200 patients (107 men and 93 women) who underwent L-spine computed tomography were enrolled in this study. The mean age of the patients was 55.6 +/- 18.3 years (range, 13 to 92 years). The spino-iliac angle (SIA) was measured on the axial image at the S1 level, which was defined as the angle between a vertical line through the center of the spinous process and an oblique line that passed through the center of the outer and inner cortices of the ilium. RESULTS The group mean SIA was 30.1 degrees +/- 7.8 degrees ; 30.1 degrees +/- 7.7 degrees for men and 29.9 degrees +/- 81.1 degrees for women. There was no significant difference according to gender or age (p > 0.05). CONCLUSIONS The SIA for the axial trajectory of iliac screws is approximately 30 degrees in Korean patients.