Ultrasound-guided suprainguinal fascia iliaca block to position the patient for neuraxial anaesthesia in acetabular surgery - a randomized controlled pilot study.

INTRODUCTION: Neuraxial anaesthesia is a common choice for most hip and lower limb operations. Pain associated with positioning is often a deterrent, and the vast literature suggests different regional blocks and opioids for these patients. Patients with acetabular fractures may experience increased pain, and thus are more difficult to position for the neuraxial block. We conducted a randomized controlled pilot study to assess and compare the analgesic efficacy of ultrasound-guided suprainguinal fascia iliaca block (SFICB) versus systemic fentanyl to facilitate positioning for combined spinal epidural (CSE) anaesthesia in patients undergoing acetabular fracture surgery. MATERIAL AND METHODS: Twenty patients referred for surgical repair of acetabular fractures were randomly assigned to receive either ultrasound-guided SFICB (group B) or intravenous fentanyl (group F). Changes in visual analogue scale (VAS) scores in supine and sitting position, improvement in sitting angle (SA), positioning quality, rescue analgesic requirement, total opioid consumption, comfort VAS scores, and complications were noted to compare both groups. RESULTS: The post-intervention VAS score in the sitting position was significantly lower in group B than in group F (5.9 ± 2.1 vs. 3.5 ± 1.5, P = 0.01). Group B also had more significant improvement in SA (27.5° (20.75-36.5°), in comparison to group F (10 (5-18.75), P = 0.006). The positioning quality was better in group B, with 70% of patients achieving an optimal position compared to only 10% in group F ( P = 0.02). CONCLUSIONS: Ultrasound-guided SFICB, as compared to systemic fentanyl, provided better analgesia and helped to achieve a better and more comfortable position to perform the neuraxial block.

The relationship between stone-free and patient position in retrograde intrarenal surgery: a randomized prospective study.

PURPOSE: Residual fragments not removed with urinary stone surgery may become symptomatic. In this context, this study was carried out to investigate the effect of performing retrograde intrarenal surgery, which is conventionally performed in the lithotomy position, in the modified lithotomy position (Trend-side) on stone-free rates following the surgery. METHODS: This prospective study consisted of 100 patients with a single kidney stone smaller than 2 cm between 2021 and 2023. These patients were randomized into two groups of 50 patients each to be operated on in the conventional lithotomy and Trend-side positions. Variables were compared using independent t test for continuous variables and chi-square test for categorical variables. RESULTS: There was no significant difference between the lithotomy and Trend-side position groups in terms of preoperative size, density, location of the stone, and hydronephrosis degree. Stone-free rate was 72% (n = 36) in the lithotomy group and 92% (n = 46) in the Trend-side group. Hence, there was a significant difference between the groups in the stone-free rate in favor of the Trend-side group (p = 0.009). Fragmentation time was statistically significantly shorter in the Trend-side group than in the lithotomy group (34 ± 17 min vs. 43 ± 14 min; p = 0.006). There was no significant difference between the groups in postoperative complication rates. CONCLUSION: Performing retrograde intrarenal surgery in the Trend-side position shortened the duration of fragmentation compared to the lithotomy position and was associated with higher stone-free rates. In conclusion, the Trend-side position can be safely preferred in patients undergoing retrograde intrarenal surgery due to kidney stones.

Comparison of supine-prone percutaneous nephrolithotomy methods in the treatment of kidney stones in pediatric patients: prospective randomized study.

Mini-PCNL is one of the most effective surgical methods in the treatment of kidney stones in pediatric patients. In this study, we aimed to compare PCNL in the supine-prone position in pediatric patients (especially operation time, postop complications, hospital stay and stone-free rates).We conducted our study in a randomized and prospective manner. Patients with lower pole stones larger than 1 cm, stones larger than 1.5 cm in the pelvis, upper pole, midpole or multiple locations, and patients who did not respond to ESWL or whose family that preferred mini-PCNL to be the primary treatment were included in the study. Patients with any previous kidney stone surgery, patients with coagulation disorders and patients with retrorenal colon were excluded from the study. Between 2021 and 2023, a total of 144 patients underwent PCNL. 68 of these patients had supine PCNL and 76 prone PCNL. Postoperative Clavien grade1 complication occurred in a total of 7 patients in the prone position; Clavien grade1 complication occurred in 1 patient in the supine position. The mean operation time for prone PCNL was 119.88 ± 28.32 min, and the mean operative time for supine PCNL was 98.12 ± 14.97 the mean hospitalization time in prone PCNL was 3.56 ± 1.12 days, and 3.00 ± 0.85 days in supine PCNL. In conclusion, supine PCNL is a safe and effective method in the treatment of pediatric kidney stones and postoperative complications were observed to be less; the operation time and hospital stay were shorter in supine PCNL.

Anesthesia for the Patient Undergoing Shoulder Surgery.

Shoulder surgery introduces important anesthesia considerations. The interscalene nerve block is considered the gold standard regional anesthetic technique and can serve as the primary anesthetic or can be used for postoperative analgesia. Phrenic nerve blockade is a limitation of the interscalene block and various phrenic-sparing strategies and techniques have been described. Patient positioning is another important anesthetic consideration and can be associated with significant hemodynamic effects and position-related injuries.

Efficacy and safety of video double-lumen tube intubation in lateral position in patients undergoing thoracic surgery: a randomized controlled trial.

BACKGROUND: Video double-lumen tube (VDLT) intubation in lateral position is a potential alternative to intubation in supine position in patients undergoing thoracic surgery. This non-inferiority trial assessed the efficacy and safety of VDLT intubation in lateral position. METHODS: Patients (18-70 yr) undergoing right thoracoscopic lung surgery were randomized to either the left lateral position group (group L) or the supine position group (group S). The VDLT was placed under video larygoscopy. The primary endpoint was the intubation time. Secondary endpoints included VDLT displacement rate, intubation failure rate, the satisfaction of surgeon and nurse, and intubation-related adverse events. RESULTS: The analysis covered 80 patients. The total intubation time was 52.0 [20.4]s in group L and 34.3 [13.2]s in group S, with a mean difference of 17.6 s [95% confidence interval (CI): 9.9 s to 25.3 s; P = 0.050], failing to demonstrate non-inferiority with a non-inferiority margin of 10 s. Group L, compared with group S, had significantly lower VDLT displacement rate (P = 0.017) and higher nurse satisfaction (P = 0.026). No intubation failure occurred in any group. Intubation complications (P = 0.802) and surgeon satisfaction (P = 0.415) were comparable between two groups. CONCLUSIONS: The lateral VDLT intubation took longer time than in the supine position, and non-inferiority was not achieved. The incidence of displacement as the secondary endpoint was lower in the L group, possibly due to changing body positions beforehand. The indication of lateral VDLT intubation should be based on a balance between the safety of airway management and the lower incidence of displacement. TRIAL REGISTRATION: The study was registered at Chictr.org.cn with the number ChiCTR2200064831 on 19/10/2022.

Comparative analysis of ultrasound-guided percutaneous biopsy of native kidneys in children and adults using the free-flank supine antero-lateral decubitus positioning.

PURPOSE: Ultrasound-guided percutaneous biopsy (USPB) of the native kidneys is the preferred diagnostic method for several nephrological conditions in both adult and pediatric populations. Conventionally, native kidney biopsies are conducted with patients in the prone position (PP). However, an alternative approach involving the supine oblique antero-lateral position (SALP) has been explored, particularly for individuals who are obese, elderly, or critically ill. METHODS: This study aimed to assess the feasibility and outcomes of USPB performed in SALP with a Free-Flank setting (FF-SALP) in pediatric patients (Group A) compared to adults (Group B). Data from kidney biopsies conducted between 2008 and 2021 were gathered. The study focused on the safety and the prevalence of biopsy samples containing a minimum of 10 glomeruli, histopathological yield in both groups. RESULTS: Complication rates were low in both groups (5.6% vs. 3.7%; p = 0.454), without major complications noted. The pediatric group achieved a significantly higher mean number of glomeruli per biopsy compared to the adult group (20.6 ± 12.3 vs. 15.7 ± 9.4; p < 0.001). However, when evaluating the minimum threshold of 10 glomeruli (76.3% vs. 68.5%; p = 0.072) and histopathologic yield (95.3% vs. 93.5%; p = 0.408), no differences were observed between groups. CONCLUSION: USPB of native kidneys in the FF-SALP position is a safe and effective method for tissue sampling in patients with parenchymal disease. It demonstrated comparable diagnostic yields and complication rates in the pediatric and adult populations, providing advantages in terms of airway management, making it particularly useful for pediatric patients that require general anesthesia.

[Development and clinical application of lateral segmental positioning plates of the body surface spine].

OBJECTIVE: To investigate the clinical efficacy of body-surface guide plates for lateral segmental positioning in the thoracolumbar spine. METHODS: From March 2018 to March 2021, 768 gerontal patientss underwent percutaneous vertebroplasty with balloon dilatation due to thoracolumbar compression fracturess, 356 males and 412 females. aged from 64 to 92 years old with an average of (77.9±13.5) years old. All patients were treated in hospital within 1 week after injury. All patients underwent preoperative localization, and were divided into localization plate group and locator group according to different localization methods. There were 390 patients in the localization plate group, 180 males and 210 females, aged from 64 to 92 years old, with an average age of (78.4±14.3) years old. There were 378 patients in the locator group, 176 males and 202 females, aged from 64 to 90 years old, with an average age of (77.5±13.4) years old. After preliminary positioning with the above two methods, skin markers were made, cloth was routinely disinfected, and the spinal lateral position was fluoroscopically examined after the fine needle was inserted into the marked point and the vertical body at the near tail end. The accuracy of the original positioning method was evaluated. The number of times, time and accuracy of positioning of the two groups of patients were compared and analyzed. RESULTS: The specific data of patient positioning in the two groups were collected for statistical analysis. The number of times of fluoroscopy in the positioning plate group and the locator group was(3.3±0.5) times and (5.0±1.2) times, and the positioning time was (60.4±9.4) s and (105.0±30.9) s, respectively. The accuracy of fluoroscopy was 97.5% (380/390) and 85.7% (324/378), respectively, with statistical significance (P<0.05). CONCLUSION: The lateral segmental positioning plate of the body surface spine has the advantages of simple operation, accurate positioning, and reducing X-ray radiation for patients, which is worthy of clinical application.

The Effect of Intraoperative Patient Positioning on the Success of Intertrochanteric Fracture Surgery in Older Patients.

Background and Objectives: The incidence of hip fractures in people of advanced ages is increasing due to our aging society. Patient positioning for the intertrochanteric fractures of the femur can be performed in various ways. The aim of this study is to clinically and radiologically compare the use of the supine hemilithotomy position, the lateral decubitus position, and the traction table when performing proximal femoral nail (PFN) surgery for femoral intertrochanteric fractures in the geriatric age group. Materials and Methods: A total of 170 elderly patients with femoral intertrochanteric fractures were included in this cross-sectional study. The patients were divided into three groups (the supine hemilithotomy group, the lateral decubitus group, and the fracture table group). For the postoperative period, complications, length of stay in the intensive care unit, and length of stay in hospital were examined, while in postoperative radiographs, tip-apex distances (TADs), collodiaphyseal angles (CDAs), and Cleveland-Bosworth quadrants were examined to evaluate the placement of the lag screw in the femoral head. The quality of fracture reduction was evaluated according to the modified Baumgaertner criteria. Results: The mean age of the patients was 77.8 ± 8.8; 57.6% of patients were female. According to the modified Baumgaertner criteria, it was determined that patients with 'poor' reduction quality had an approximately ten times higher risk of cut-out than those with 'good' reduction quality (OR = 10.111, p = 0.002, 95% confidence interval; 2.313-44.207). The operative time for patients in the fracture table group was longer than that of the other groups Additionally, the CDA in the supine hemilithotomy position group was longer. Conclusions: Although PFN surgery using the traction table is longer in terms of surgical time compared to surgery performed in the lateral decubitus position and the supine hemilitotomy position, it is advantageous in terms of better TAD and CDA values and lower complication rates.

Is intramedullary nailing of femoral diaphyseal fractures in the lateral decubitus position as safe and effective as on a traction table?

OBJECTIVES: The aim of this study was to compare the radiological and clinical results of femoral diaphyseal fractures operated in the lateral decubitus position with those operated in the supine position on a traction table and to detail the perioperative surgical technique. PATIENTS AND METHODS: Between October 2018 and January 2022, in this prospective, randomized, and single-blind comparative study, 75 patients diagnosed with adult femoral diaphyseal fractures to whom intramedullary nails were applied were operated in the lateral decubitus position without a traction table (Group 1, 37 patients) and in the supine position with a traction table (Group 2, 38 patients). Preoperative age, gender, fracture mechanism, fracture type, and surgical waiting times were determined. Perioperative anesthesia type, surgery preparation time, surgical time, number of fluoroscopy doses, amount of bleeding, and type of reduction were evaluated, and detailed observational descriptions of the surgical techniques were made. In the postoperative period, radiological evaluations were made with x-ray radiography and orthoroentgenogram, while in the clinical evaluation, hip-knee joint range of motion and rotational evaluation were made with the Craigs test. Follow-up periods were determined and complications noted. RESULTS: The average age was 32 in Group 1 and 28 in Group 2, the female/male ratio was 1:36 in Group 1 and 5:33 in Group 2, and the follow-up period was 18.2 months Group 1 and 21.7 months in Group 2. No significant difference was detected between the groups in terms of age, gender, fracture mechanism, fracture type, anesthesia type, surgical waiting time, and follow-up period (p > 0.05). Compared to Group 2, the shorter preparation time, surgical time, and number of fluoroscopy doses in Group 1 were found to be statistically significant (p < 0.05). The differences in the amount of bleeding and need for open reduction were not statistically significant between the groups (p > 0.05), and no statistical difference was found in joint range of motion and rotational evaluation in clinical evaluation in both groups (p > 0.05). There was no significant difference in terms of complications between groups. CONCLUSIONS: We found the lateral decubitus method without a traction table to be a safe and effective alternative to the supine method with a traction table in terms of the radiological and clinical results and that it also has the advantages of shortening the surgical time, reducing radiation exposure. LEVEL OF EVIDENCE: Level 1 prospective, randomized, single-blind controlled study.

Flank versus prone position in percutaneous nephrolithotomy: a meta-analysis of randomized controlled studies.

The objective of this study is to assess the safety and efficacy of the flank position in percutaneous nephrolithotomy (PCNL). We searched PubMed, Embase, SCOPUS, the Cochrane database libraries, and the Chinese Biomedical Literature Database, and randomized controlled trials (RCTs) assessing PCNL in flank position are included in this meta-analysis. The related trials met the inclusion criteria were analyzed using RevMan 5.4. Seven randomized controlled trials were included, involving a total of 587 patients. We found that there was a lower decrease in hemoglobin levels in the flank position group compared to prone-position group (mean difference [MD] = - 0.15, 95% confidence interval (CI) - 0.22 to - 0.08, P < 0.00001). Moreover, our meta-analysis demonstrated no significant differences between groups regarding stone-free rate (relative risk [RR] = 1.00, 95% CI 0.93 to 1.06, P = 0.92), operative time(MD = 0.76, 95% CI - 5.31 to 6.83, P < 0.00001), hospital stay (MD = 0.03, 95% CI - 0.32 to 0.32, P < 0.00001), and complications Clavien grade I (RR = 1.01, 95% CI 0.98 to 1.05, P = 0.54), Clavien grade II (RR = 1, 95% CI 0.97 to 1.02, P = 0.78), and Clavien grade III (RR = 1, 95% CI 0.98 to 1.03, P = 0.77). The use of flank position for PCNL is associated with reduced hemoglobin change without an increase in complications. This positioning technique can be considered safe for patients with nephrolithiasis and may be particularly suitable for high-risk individuals such as those who are obese or have decreased cardiopulmonary function. However, further randomized trials are needed to confirm these findings.

Characterization of the IDENTIFYTM surface scanning system for radiation therapy setup on a closed-bore linac.

PURPOSE: In radiation therapy, surface guidance can be used for patient setup and intra-fraction motion monitoring. The surface guided radiation therapy (SGRT) system from Varian Medical systems, IDENTIFYTM, consists of three pods, including cameras and a random pattern projector, mounted on the ceiling. The information captured by the cameras is used to make a reconstruction of the surface. The aim of the study was to assess the technical performance of this SGRT system on a closed-bore linac. METHODS: Phantom measurements were performed to assess the accuracy, precision, reproducibility and temporal stability of the system, both in align and in load position. Translations of the phantoms in lateral, longitudinal, and vertical direction, and rotations around three axes (pitch, roll and yaw) were performed with an accurate, in-house built, positioning stage. Different phantom geometries and different surface colors were used, and various ambient light intensities were tested. RESULTS: The accuracy of the IDENTIFYTM system at the closed-bore linac was 0.07 mm and 0.07 degrees at load position, and 0.06 mm and 0.01 degrees at align position for the white head phantom. The precision was 0.02 mm and 0.02 degrees in load position, and 0.01 mm and 0.02 degrees in align position. The accuracy for the Penta-Guide phantom was comparable to the white head phantom, with 0.06 mm and 0.01 degrees in align position. The system was slightly less accurate for translations of the CIRS lung phantom in align position (0.20 mm, 0.05 degrees). Reproducibility measurements showed a variation of 0.02 mm in load position. Regarding the temporal stability, the maximum drift over 30 min was 0.33 mm and 0.02 degrees in load position. No effect of ambient light level on the accuracy of the IDENTIFYTM system was observed. Regarding different surface colors, the accuracy of the system for a black phantom was slightly worse compared to a white surface, but not clinical relevant. CONCLUSION: The IDENTIFYTM system can adequately be used for motion monitoring on a closed-bore linac with submillimeter accuracy. The results of the performed measurements meet the clinical requirements described in the guidelines of the AAPM and the ESTRO.

Comparison of volume-controlled ventilation, pressure-controlled ventilation and pressure-controlled ventilation-volume guaranteed in infants and young children in the prone position: A prospective randomized study.

STUDY OBJECTIVE: To explore if the pressure-controlled ventilation (PCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) modes are superior to volume-controlled ventilation (VCV) in optimizing intraoperative respiratory mechanics in infants and young children in the prone position. DESIGN: A single-center prospective randomized study. SETTING: Children's Hospital, Zhejiang University School of Medicine. PATIENTS: Pediatric patients aged 1 month to 3 years undergoing elective spinal cord detethering surgery. INTERVENTIONS: Patients were randomly allocated to the VCV group, PCV group and PCV-VG group. The target tidal volume (VT) was 8 mL/kg and the respiratory rate (RR) was adjusted to maintain a constant end tidal CO2. MEASUREMENTS: The primary outcome was intraoperative peak airway pressure (Ppeak). Secondary outcomes included other respiratory and ventilation variables, gas exchange values, serum lung injury biomarkers concentration, hemodynamic parameters and postoperative respiratory complications. MAIN RESULTS: A total of 120 patients were included in the final analysis (40 in each group). The VCV group showed higher Ppeak at T2 (10 min after prone positioning) and T3 (30 min after prone positioning) than the PCV and PCV-VG groups (T2: P = 0.015 and P = 0.002, respectively; T3: P = 0.007 and P = 0.009, respectively). The prone-related decrease in dynamic compliance was prevented by PCV and PCV-VG ventilation modalities at T2 and T3 than by VCV (T2: P = 0.008 and P = 0.015, respectively; T3: P = 0.015 and P = 0.014, respectively). Additionally, there were no significant differences in other secondary outcomes among the three groups. CONCLUSION: In infants and young children undergoing spinal cord detethering surgery in the prone position, PCV-VG may be a better ventilation mode due to its ability to mitigate the increase in Ppeak and decrease in Cdyn while maintaining consistent VT.

A reduction method for anterior opening displacement in thoracolumbarvertebral fractures with diffuse idiopathic skeletal hyperostosis using the skull clamp-assisted position.

Diffuse idiopathic skeletal hyperostosis (DISH) frequently occurs in the spine, resulting in unstable fractures. Treating thoracolumbar fractures in patients with DISH is often difficult because the anterior opening of the vertebral body is exacerbated by dislocation in the prone position, making reduction difficult. In this study, we introduced a novel skull clamp-assisted positioning (SAP) technique. The patient is placed in a supine position with a skull clamp used in cervical spine surgery before surgery to prevent the progression of dislocation and to restore the patient's position. Using this method, the mean difference in local kyphosis angle improved from -2.9 (±8.4)° preoperatively to 10.9 (±7.7)° postoperatively. Furthermore, posterior displacement decreased from a preoperative mean of 5.5 (±4.3) mm to 0.3 (±0.7) mm postoperatively. Complications such as neurological sequelae, implant fracture, and surgical site infection were not observed through one year of postoperative follow-up. SAP may decrease invasiveness and complications. Longer-term studies and larger sample sizes are needed to establish long-term efficacy and benefits.

Use of the spider limb positioner for fibular free flap reconstruction of head and neck bony defects.

BACKGROUND: Osseous and osteocutaneous fibular free flaps are the workhorse of maxillomandibular reconstruction over 30 years after the initial description. Since 2019, we have routinely used the Spider Limb Positioner, adapted from its use in shoulder orthopedic procedures, for fibular free flap harvest. Herein, we describe this novel technique in our cohort. METHODS: We describe our intraoperative setup and endorse the versatility and utility of this technique in comparison to other reported fibular free flap harvest techniques. RESULTS: The Spider Limb Positioner was used 61 times in 60 different patients to harvest osseous or osteocutaneous fibular free flaps. Median (range) tourniquet time for flap harvest was 90 (40-124) minutes. No iatrogenic nerve compression injuries or complications related to lower extremity positioning occurred. CONCLUSION: We describe a novel approach to fibular free flap harvest utilizing the Spider Limb Positioner, which affords optimal ergonomics, visibility, and patient repositioning. There were no nerve injuries or complications related to positioning in our series.

Accuracy of cup placement and pelvic motion in total hip arthroplasty in the lateral decubitus position using a new computed tomography-based navigation system with augmented reality technology.

INTRODUCTION: This study aimed to investigate the accuracy of cup position and assess the changes in pelvic tilt during primary total hip arthroplasty (THA) in the lateral decubitus position using a new computed tomography (CT)-based navigation system with augmented reality (AR) technology. MATERIALS AND METHODS: There were 37 cementless THAs performed using a CT-based navigation system with AR technology in the lateral decubitus position and 63 cementless THAs performed using manual implant techniques in the lateral decubitus position in this retrospective study. Postoperative cup radiographic inclination and anteversion were measured using postoperative CT, and the proportion of hips within Lewinnek's safe zone was analyzed and compared between the two groups. The mean absolute values of navigation error were assessed. Intraoperative pelvic tilt angles were also recorded using navigation system. RESULTS: The percentage of cups inside Lewinnek's safe zone was 100% in the navigation group and 35% in the control group (p < 0.001). The mean absolute values of navigation error in inclination and anteversion were 2.9° ± 2.1° and 3.3° ± 2.4°, respectively. The mean abduction angle of the pelvis was 5.1° ± 4.8° after placing the patients in the lateral decubitus position and 4.1° ± 6.0° after cup placement. The mean posterior tilt angle was 6.8° ± 5.1° after placing the patients in the lateral decubitus position and 9.3° ± 5.9° after cup placement. The mean internal rotation angle was 14.8° ± 7.4° after cup placement. There were no correlations between the navigation error in inclination or anteversion and the absolute values of changes of the pelvic tilt angle at any phase. CONCLUSIONS: Although progressive pelvic motion occurred in THA in the lateral decubitus position, especially during cup placement, the CT-based navigation system with AR technology improved cup placement accuracy.

Postoperative cognitive dysfunction after beach chair positioning compared to supine position in orthopaedic surgery in the elderly.

INTRODUCTION: Postoperative cognitive dysfunction (POCD) occurs in up to 26% of patients older than 60 years 1 week after non-cardiac surgery. Intraoperative beach chair positioning (BCP) is advantageous for some types of shoulder surgery. However, this kind of positioning leads to a downward bound redistribution of blood volume, with possible hypoperfusion of the brain. We hypothesized that patients > 60 years undergoing orthopaedic shoulder surgery in a BCP might experience more POCD than patients operated in the supine position (SP). MATERIAL AND METHODS: A single-centre, prospective observational trial of 114 orthopaedic patients was performed. Study groups were established according to the type of intraoperative positioning. Anaesthesiological management was carried out similarly in both groups, including types of anaesthetics and blood pressure levels. POCD was evaluated using the Trail Making Test, the Letter-Number Span and the Regensburger Word Fluency Test. The frequency of POCD 1 week after surgery was considered primary outcome. RESULTS: Baseline characteristics, including duration of surgery, were comparable in both groups. POCD after 1 week occurred in 10.5% of SP patients and in 21.1% of BCP patients (p = 0.123; hazard ratio 2.0 (CI 95% 0.794-5.038)). After 4 weeks, the incidence of POCD decreased (SP: 8.8% vs. BCP: 5.3%; p = 0.463). 12/18 patients with POCD showed changes in their Word Fluency Tests. Near-infrared spectroscopy (NIRS) values were not lower in patients with POCD compared to those without POCD (54% (50/61) vs. 57% (51/61); p = 0.671). CONCLUSION: POCD at 1 week after surgery tended to occur more often in patients operated in beach chair position compared to patients in supine position without being statistically significant.

Comparison of patient setup accuracy for optical surface-guided and X-ray-guided imaging with respect to the impact on intracranial stereotactic radiotherapy.

PURPOSE: The objective of this work is to estimate the patient positioning accuracy of a surface-guided radiation therapy (SGRT) system using an optical surface scanner compared to an X­ray-based imaging system (IGRT) with respect to their impact on intracranial stereotactic radiotherapy (SRT) and intracranial stereotactic radiosurgery (SRS). METHODS: Patient positioning data, both acquired with SGRT and IGRT systems at the same linacs, serve as a basis for determination of positioning accuracy. A total of 35 patients with two different open face masks (578 datasets) were positioned using X­ray stereoscopic imaging and the patient position inside the open face mask was recorded using SGRT. The measurement accuracy of the SGRT system (in a "standard" and an SRS mode with higher resolution) was evaluated using both IGRT and SGRT patient positioning datasets taking into account the measurement errors of the X­ray system. Based on these clinically measured datasets, the positioning accuracy was estimated using Monte Carlo (MC) simulations. The relevant evaluation criterion, as standard of practice in cranial SRT, was the 95th percentile. RESULTS: The interfractional measurement displacement vector of the SGRT system, σSGRT, in high resolution mode was estimated at 2.5 mm (68th percentile) and 5 mm (95th percentile). If the standard resolution was used, σSGRT increased by about 20%. The standard deviation of the axis-related σSGRT of the SGRT system ranged between 1.5 and 1.8 mm interfractionally and 0.5 and 1.0 mm intrafractionally. The magnitude of σSGRT is mainly due to the principle of patient surface scanning and not due to technical limitations or vendor-specific issues in software or hardware. Based on the resulting σSGRT, MC simulations served as a measure for the positioning accuracy for non-coplanar couch rotations. If an SGRT system is used as the only patient positioning device in non-coplanar fields, interfractional positioning errors of up to 6 mm and intrafractional errors of up to 5 mm cannot be ruled out. In contrast, MC simulations resulted in a positioning error of 1.6 mm (95th percentile) using the IGRT system. The cause of positioning errors in the SGRT system is mainly a change in the facial surface relative to a defined point in the brain. CONCLUSION: In order to achieve the necessary geometric accuracy in cranial stereotactic radiotherapy, use of an X­ray-based IGRT system, especially when treating with non-coplanar couch angles, is highly recommended.

Gel Rolls Increase Percutaneous Nephrolithotomy Radiation Exposure.

Introduction: Despite increasing interest in reducing radiation doses during endoscopic stone surgery, there is conflicting evidence as to whether percutaneous nephrolithotomy (PCNL) positioning (prone or supine) impacts radiation. We observed clinically that a patient placed prone on gel rolls had higher than expected radiation with intraoperative CT imaging and that gel rolls were visible on the coaxial imaging. We hypothesized that gel rolls directly increase radiation doses. Methods: Anthropomorphic experiments to simulate PCNL positions were performed using a robotic multiplanar fluoroscopy system (Artis Zeego Care+Clear, Siemens) and a 5-second coaxial imaging protocol (5s BODY). A fluoroscopy phantom was placed in various positions, including prone on a gel roll; prone on blankets of equal thickness; prone and supine directly on the table; and modified supine (MS) positions using a thin gel roll or rolled blanket. Impacts of C-arm direction and use of a 1 L saline bag were also evaluated. Measured dose area product (DAP) was compared for the groups. Results: Measured DAP was found to increase by 146 µGy*m2 (287%) when prone on gel rolls compared with only 62.29 (23%) when placed on blankets of equal thickness, although the model likely both overstates the relative impact and understates the absolute impact that would be seen clinically. Measured DAP between experimental groups also varied considerably despite fluoroscopy time being held constant. Conclusions: Our experiments support our hypothesis that gel rolls directly increase radiation dose, which has not been previously reported, using an anthropomorphic model. Surgeons should consider radiolucent materials for positioning to limit radiation exposure to patients and the surgical team.