OBJECTIVE: To compare the effectiveness of percutaneous short-segment injured vertebra pedicle screw fixation combined with bone grafting versus percutaneous short-segment injured vertebra pedicle screw fixation alone for the treatment of thoracolumbar fractures. METHODS: The clinical data of 54 patients with single-level thoracolumbar fractures who met the selection criteria between January 2023 and February 2024 were retrospectively analysed. Based on whether bone grafting was performed on the injured vertebra, the patients were divided into a control group (28 cases, percutaneous short-segment injured vertebra pedicle screw fixation alone) and a study group (26 cases, percutaneous short-segment injured vertebra pedicle screw fixation combined with bone grafting using a self-made minimally invasive bone grafting funnel). No significant difference was observed between the two groups ( P>0.05) in baseline data, including age, gender, surgical segment, cause of injury, AO classification, and preoperative anterior-vertebral height compression ratio, mid-vertebral height compression ratio, Cobb angle, visual analogue scale (VAS) score, and Oswestry Disability Index (ODI). The operation time, intraoperative blood loss, fracture healing status, removal time of internal fixator, and complications were recorded and compared between the two groups. Effectiveness was assessed using anterior-vertebral height compression ratio, mid-vertebral height compression ratio, Cobb angle, VAS scores, and ODI taken preoperatively, at 1 week postoperatively, and at last follow-up. RESULTS: All patients in both groups successfully underwent surgery. The operation time and intraoperative blood loss in the control group were significantly less than those in the study group ( P<0.05). No significant difference was observed in the follow-up time between the study group [(14.46±2.00) months] and control group [(14.36±1.83) months] ( P>0.05). The fracture healing time of the study group was significantly shorter than that of the control group ( P<0.05). One patient in the study group was found to have bilateral titanium rod breakage by X-ray reexamination at 8 months after operation, and there was no subsequent vertebral height collapse occurred, and the internal fixator was removed following complete fracture healing. The other patients had no complication such as spinal cord injury, internal fixator loosening and breakage. There was no significant difference in the removal time of internal fixator between the two groups ( P<0.05). The anterior-vertebral height compression ratio, mid-vertebral height compression ratio, Cobb angle, VAS score, and ODI significantly improved in both groups at 1 week after operation and at last follow-up ( P<0.05). Among them, the VAS score, and ODI further improved at last follow-up when compared with at 1 week after operation, Cobb angle lost a little at 1 week after operation, while anterior-vertebral height compression ratio and mid-vertebral height compression ratio slightly increased when compared with 1 week after operation, and the differences were significant ( P<0.05). There was no significant difference between the two groups in Cobb angle at last follow-up, VAS score and ODI at 1 week after operation ( P>0.05), while the other indicators in the study group were significantly better than those in the control group at all time points ( P<0.05). CONCLUSION Compared to percutaneous short-segment injured vertebra pedicle screw fixation alone, the technique combined with intravertebral bone grafting can shorten fracture healing time, effectively restore and maintain vertebral body height, correct kyphotic deformity, and improve clinical outcomes for patients with thoracolumbar fractures.
Humans ; Thoracic Vertebrae/surgery* ; Pedicle Screws ; Lumbar Vertebrae/surgery* ; Spinal Fractures/surgery* ; Bone Transplantation/methods* ; Fracture Fixation, Internal/instrumentation* ; Male ; Female ; Retrospective Studies ; Adult ; Middle Aged ; Treatment Outcome ; Minimally Invasive Surgical Procedures/methods* ; Operative Time ; Aged

OBJECTIVE: To investigate the effectiveness of TiRobot-assisted minimally invasive treatment for fragility fractures of the pelvis (FFP) in elderly patients. METHODS: A retrospective analysis was conducted on the clinical data of 176 patients with FFP who were admitted between July 2018 and July 2024 and met the selection criteria. Among them, 95 patients underwent TiRobot-assisted closed reduction and minimally invasive cannulated screw fixation (robot group), while 81 patients underwent traditional open reduction and plate screw fixation (control group). There was no significant difference in baseline data such as gender, age, fracture classification, disease duration, and preoperative visual analogue scale (VAS) pain scores between the two groups ( P>0.05). The following parameters were recorded and compared between the two groups, including operation time, intraoperative blood loss, intraoperative transfusion rate, volume of intraoperative blood transfusion, maximum incision length, hospital stay, maximum residual displacement, reduction quality, fracture healing time, incidence of complications, VAS scores, Majeed pelvic function scores, and functional grading. RESULTS: All surgeries in both groups successfully completed. The robot group exhibited significantly shorter operation time, reduced intraoperative blood loss, lower intraoperative transfusion rate, smaller volume of intraoperative blood transfusion, shorter maximum incision length, and shorter hospital stay compared to the control group ( P<0.05). In the robot group, a total of 14 INFIX internal fixation frames and 280 cannulated screws were implanted, among which 250 screws were rated as excellent, 17 as good, and 13 as poor, resulting in a screw placement excellent and good rate of 95.36%. Radiological review revealed that the excellent and good rate of reduction quality was in 91.58% (87/95) in the robot group and 81.48% (66/81) in the control group, with no significant difference in postoperative maximum residual fracture displacement or reduction quality between the two groups (P>0.05). All patients in both groups were followed up 12-66 months, with an average of 28.9 months, and there was no significant difference in follow-up time between the two groups ( P>0.05). The fracture healing time in the robot group was significantly shorter than that in the control group ( P<0.05). At last follow-up, both groups showed significant improvement in VAS scores compared to preoperative values ( P<0.05); the change values of VAS scores, Majeed scores, and the excellent and good rate of Majeed pelvic function were significantly higher in the robot group than in the control group ( P<0.05). Regarding postoperative complications, there was no significant difference between the two groups in terms of gait changes, secondary surgeries, heterotopic ossification, incision infections, walking difficulties, internal fixation failure, or mortality rates ( P>0.05); however, the incidence of delayed wound healing was significantly lower in the robot group than in the control group ( P<0.05). CONCLUSION TiRobot-assisted minimally invasive treatment of elderly FFP is superior to traditional open reduction and internal fixation in terms of surgical trauma control, postoperative rehabilitation speed, and functional recovery.
Humans ; Male ; Retrospective Studies ; Female ; Minimally Invasive Surgical Procedures/instrumentation* ; Fracture Fixation, Internal/instrumentation* ; Pelvic Bones/surgery* ; Aged ; Bone Screws ; Bone Plates ; Robotic Surgical Procedures/methods* ; Aged, 80 and over ; Treatment Outcome ; Osteoporotic Fractures/surgery* ; Operative Time ; Blood Loss, Surgical ; Fracture Healing ; Fractures, Bone/surgery*

OBJECTIVE: To evaluate the effectiveness of suture anchors combined with headless compression screw fixation in treating inferior pole patellar fractures. METHODS: A retrospective analysis was conducted on 36 patients with inferior pole patellar fractures, who were admitted between January 2018 and October 2024 and met the selective criteria. There were 15 males and 21 females with a mean age of 52.3 years (range, 23-81 years). The fracture were reduced and fixed using suture anchors combined with headless compression screws. The operation time, intraoperative blood loss, and the length of hospital stay were recorded. Functional recovery was assessed using knee range of motion (ROM), Hospital for Special Surgery (HSS) knee score, and Böstman patellar fracture efficacy score. RESULTS: The operation time ranged from 10 to 100 minutes, with an average of 57.6 minutes. The intraoperative blood loss was 10 to 120 mL, with an average of 73.3 mL. The length of hospital stay was 5 to 10 days, with an average of 6.3 days. All incisions healed by first intention. All 36 patients were followed up 18-24 months (mean, 20.6 months). Postoperative X-ray films indicated that the fractures had healed; no screw breakage, anchor loosening, or implant foreign body rejection reactions occurred during follow-up. At last follow-up, the ROM of the affected knee joint was (136.0±2.3)°, and there was no significant difference when compared with the healthy side (136.6±2.3)° ( t=-1.944, P=0.060). The HSS score of the affected knee joint was 96-100 (mean, 99.1), and all cases were rated as excellent. The Böstman patellar fracture efficacy score was 27-30 (mean, 29.1), and 35 cases were rated as excellent and 1 as good. CONCLUSION The suture anchors combined with headless compression screws technique provides reliable fixation for inferior pole patellar fractures. This method combines surgical simplicity with excellent functional outcomes.
Humans ; Male ; Female ; Middle Aged ; Bone Screws ; Aged ; Retrospective Studies ; Patella/surgery* ; Fracture Fixation, Internal/instrumentation* ; Adult ; Aged, 80 and over ; Suture Anchors ; Fractures, Bone/surgery* ; Range of Motion, Articular ; Treatment Outcome ; Young Adult ; Operative Time ; Length of Stay

OBJECTIVE: To explore the effectiveness of posterior single-level osteotomy with 360° release and correction for the treatment of osteoporotic vertebral compression fractures (OVCF) complicated with moderate to severe kyphosis. METHODS: A retrospective analysis was conducted on 11 patients with OVCF complicated with moderate to severe kyphosis between January 2022 and March 2023. There were 4 males and 7 females with an average age of 57 years ranging from 47 to 69 years. The disease duration ranged from 3 to 15 months, with an average of 7 months. Fracture segments included T ₁₁ in 3 cases, T ₁₂ in 5, L ₁ in 2, and L ₂ in 1. The T value of lumbar spine bone density was -5.0 to -2.0, with an average of -3.5. The preoperative neurological function was grade E according to Frankel grading. The Pfirrmann classification of the intervertebral disc above the injured vertebra was grade Ⅲ in 8 cases and grade Ⅳ in 3 cases. All patients underwent posterior single-level osteotomy with 360° release and correction. The operation time, intraoperative blood loss, hospital stay, and postoperative complications were recorded. Thoracolumbar local kyphosis Cobb angle, the mean height of the functional spinal unit (FSU), the sagittal vertical axis (SVA), and the sagittal index (SI) were measured. The visual analogue scale (VAS) score and Oswestry disability index (ODI) were used to evaluate the improvement of pain and function before operation, at 1 month after operation, and at last follow-up. RESULTS: The operation successfully completed in all patients, and there was no obvious complication. The operation time ranged from 100 to 190 minutes, with an average of 153 minutes, and the intraoperative blood loss ranged from 200 to 800 mL, with an average of 468 mL. The length of hospital stay was 8-14 days (mean, 12 days). All patients were followed up 6-24 months, with an average of 12.4 months. At last follow-up, all the 11 patients had bony fusion in the osteotomy area, and there was no displacement or subsidence of the Cage, no complication such as internal fixation failure or pseudarthrosis formation was found. The Cobb angle of local thoracolumbar kyphosis, the mean height of FSU, SVA, and SI significantly improved immediately after operation and at last follow-up when compared with preoperative ones, and the VAS score and ODI also significantly improved at 1 month after operation and at last follow-up ( P<0.05); there was no significant difference in above indexes between the two time points after operation ( P>0.05). CONCLUSION Posterior single-level osteotomy with 360° release and correction is an effective surgical method for treating OVCF complicated with moderate to severe kyphosis, with definite early effectiveness.
Humans ; Kyphosis/etiology* ; Male ; Female ; Osteotomy/methods* ; Middle Aged ; Retrospective Studies ; Aged ; Spinal Fractures/diagnostic imaging* ; Fractures, Compression/diagnostic imaging* ; Osteoporotic Fractures/complications* ; Treatment Outcome ; Lumbar Vertebrae/injuries* ; Thoracic Vertebrae/injuries* ; Operative Time ; Fracture Fixation, Internal/methods*

PURPOSE: Percutaneous ilio-sacral screw (ISS) insertion using conventional C-arm fluoroscopy has been a widely employed technique for pelvic posterior ring fixation, particularly in developing regions. However, this approach presents technical challenges, leading to a high malposition rate. We introduced a new method for ISS insertion without additional equipment or software and suggested whether it could reduce the malposition rate and operating time. METHODS: This is a retrospective cohort study. The study included all patients who underwent percutaneous ISS fixation between January 2020 and December 2022. Patients treated with open reduction or other types of implants were excluded. The patients were divided into 2 groups based on the screw insertion method: Group A utilized the traditional dual-plane adjustment method, while Group B received the newly introduced method. In all cases, conventional C-arm fluoroscopy was the sole guidance during the surgical procedure. Malposition rate, radiation exposure, and operating time were compared between groups. Post-operative CT scans were used to assess screw accuracy using the Smith grading method. The Student's t-test or the Mann-Whitney U test was chosen for comparing the quantitative variables based on the normality test results. The Chi-squared test was utilized for comparing qualitative variables. RESULTS: A total of 72 patients with pelvic posterior ring disruption treated with percutaneous ISS under conventional fluoroscopy guidance were included in this study. Among them, 32 patients were in Group A and 40 patients were in Group B. In Group B, the average operation duration per screw was 33 min with 29 fluoroscopy applications, which was significantly lower than that in Group A (44 min, p < 0.001, 38 times, p < 0.001, respectively). Furthermore, the post-operative CT scan revealed that only 10.7% (6/56) of screws in Group B were inappropriately positioned according to the Smith criteria. CONCLUSION The novel method introduced in this study demonstrated a reduction in both malposition rates and operating time compared to the traditional dual-plane adjustment method. Precise pre-operative CT planning in conjunction with conventional fluoroscopy could establish this method as a widely applicable technique for percutaneous ISS fixation.
Humans ; Fluoroscopy/methods* ; Retrospective Studies ; Bone Screws ; Female ; Male ; Tomography, X-Ray Computed/methods* ; Sacrum/diagnostic imaging* ; Middle Aged ; Operative Time ; Adult ; Fracture Fixation, Internal/methods* ; Ilium/diagnostic imaging* ; Aged

PURPOSE: The fixation method commonly employed worldwide for treating unstable fractures of the posterior pelvic ring is the percutaneous iliosacral screw technique. However, prolonged operation time and frequent fluoroscopies result in surgical risks. This study aimed to investigate whether a new triangulation method could reduce operative and fluoroscopy times and increase the accuracy of screw placement. METHODS: This study is a real-world retrospective cohort analysis that examined a patient cohort who underwent percutaneous iliosacral screw fixation between January 1, 2019 and December 31, 2022. Inclusion criteria were patients (1) diagnosed with posterior pelvic ring instability who underwent pelvic fracture closed reduction and percutaneous S1 transverse-penetrating iliosacral screw placement and (2) aged >18 years. Exclusion criteria were: (1) combined proximal femoral fractures, (2) severe soft tissue injury in the surgical area, (3) incomplete imaging data, and (4) declining to provide written informed consent by the patient. The patients were divided into 2 groups according to the screw insertion method: conventional and triangulation methods. Screw placement and fluoroscopy times recorded by the C-arm were compared between the 2 methods. The accuracy of screw placement was evaluated by Smith grading on postoperative CT. Normality tests were conducted to assess the distribution of the quantitative variables and the Chi-square test was used to compare the qualitative variables. RESULTS: The study included a total of 94 patients diagnosed with posterior pelvic ring instability, who underwent percutaneous iliosacral screw placement. The patients were divided into 2 groups: 46 patients treated with the conventional surgical method and 48 patients received the triangulation method. The operation time (61.13±9.69 vs. 35.77±6.27) min and fluoroscopy frequency times (52.15±9.29 vs. 24.40±4.04) of the triangulation method were significantly reduced (p<0.001). CONCLUSIONS The use of a triangular positioning technique for the surface positioning of percutaneous iliosacral screws could reduce the operative time and fluoroscopy frequency. And the screw placement accuracy using this new method was comparable to that using other conventional methods.
Humans ; Retrospective Studies ; Bone Screws ; Pelvic Bones/surgery* ; Male ; Female ; Fracture Fixation, Internal/methods* ; Fractures, Bone/surgery* ; Adult ; Middle Aged ; Fluoroscopy ; Aged ; Sacrum/surgery* ; Operative Time

PURPOSE: This study aims to investigate the efficacy of novel distraction support (DS) in intramedullary nailing treatment for tibial shaft fracture. METHODS: The random controlled trial included adult patients with tibial shaft fractures who were treated with intramedullary nailing at the trauma center between July 2013 and December 2018. Participants were randomly assigned to either control group (n=43) or DS group (n=42) based on whether DS was used during the operation. All surgical procedures were conducted by a single, experienced surgeon. Parameters such as hospital stay, blood loss, operative time, infection, delayed union, and malalignment were recorded for assessment. Shapiro-Wilk test was used to assess normality, and the F test was adopted to measure variance homogeneity. Continuous variables were presented as mean±standard deviation and compared via independent samples t-tests. Categorical variables are expressed as percentages. The Pearson's Chi-squared or Fisher's exact test was used for categorical variables n (%). Two-sided p<0.05 indicated statistical significance. RESULTS: A total of 85 participants were enrolled in the study. All cases achieved acceptable reduction. The operative time was significantly shorter in the DS group than in control group ((75.3±10.5) min vs. (90.4±15.5) min, p<0.001). Additionally, the DS group showed lesser blood loss ((60.1±27.2) mL vs. (85.4±25.4) mL, p<0.001). No significant differences were observed between the 2 groups in terms of hospital stay ((9.4±2.7) days vs. (10.2±3.1) days, p=0.370), infection (3 (7.1%) vs. 2 (4.7%), p=0.978), delayed union (2 (4.8%) vs. 5 (11.6%), p=0.450), and malalignment (3 (7.1%) vs. 5 (11.6%), p=0.713). CONCLUSION The use of DS in intramedullary nailing surgery is effective. The application of this DS system may represent a valuable addition to future clinical practice.
Humans ; Fracture Fixation, Intramedullary/methods* ; Tibial Fractures/surgery* ; Male ; Female ; Adult ; Middle Aged ; Operative Time ; Length of Stay ; Young Adult ; Osteogenesis, Distraction/methods*

OBJECTIVES: To evaluate the effectiveness of single-balloon and double-balloon enteroscopy in diagnosing pediatric small bowel diseases and assess the diagnostic efficacy of computed tomography enterography (CTE) for small bowel diseases using enteroscopy as the reference standard. METHODS: Clinical data from 576 children who underwent enteroscopy at Hunan Children's Hospital between January 2017 and December 2023 were retrospectively collected. The children were categorized based on enteroscopy type into the single-balloon enteroscopy (SBE) group (n=457) and double-balloon enteroscopy (DBE) group (n=119), and the clinical data were compared between the two groups. The sensitivity and specificity of CTE for diagnosing small bowel diseases were evaluated using enteroscopy results as the standard. RESULTS: Among the 576 children, small bowel lesions were detected by enteroscopy in 274 children (47.6%).There was no significant difference in lesion detection rates or complication rates between the SBE and DBE groups (P>0.05), but the DBE group had deeper insertion, longer procedure time, and higher complete small bowel examination rate (P<0.05). The complication rate during enteroscopy was 4.3% (25/576), with 18 cases (3.1%) of mild complications and 7 cases (1.2%) of severe complications, which improved with symptomatic treatment, surgical, or endoscopic intervention. Among the 412 children who underwent CTE, the sensitivity and specificity for diagnosing small bowel diseases were 44.4% and 71.3%, respectively. CONCLUSIONS SBE and DBE have similar diagnostic efficacy for pediatric small bowel diseases, but DBE is preferred for suspected deep small bowel lesions and comprehensive small bowel examination. Enteroscopy in children demonstrates relatively good overall safety. CTE demonstrates relatively low sensitivity but comparatively high specificity for diagnosing small bowel diseases.
Retrospective Studies ; Treatment Outcome ; Double-Balloon Enteroscopy/statistics & numerical data* ; Single-Balloon Enteroscopy/statistics & numerical data* ; Humans ; Male ; Female ; Child ; Operative Time ; Tomography, X-Ray Computed/statistics & numerical data* ; Sensitivity and Specificity ; Intestine, Small/surgery* ; Intestinal Diseases/surgery*

OBJECTIVE: To evaluate the early effectiveness of navigation-free robot-assisted total knee arthroplasty (TKA) compared to traditional TKA in the treatment of knee osteoarthritis combined with extra-articular deformities. METHODS: The clinical data of 30 patients with knee osteoarthritis combined with extra-articular deformities who met the selection criteria between June 2019 and January 2024 were retrospectively analyzed. Fifteen patients underwent CORI navigation-free robot-assisted TKA and intra-articular osteotomy (robot group) and 15 patients underwent traditional TKA and intra-articular osteotomy (traditional group). There was no significant difference in age, gender, body mass index, affected knee side, extra-articular deformity angle, deformity position, deformity type, and preoperative knee range of motion, American Knee Society (KSS) knee score and KSS function score, and lower limb alignment deviation between the two groups ( P>0.05). The operation time, intraoperative blood loss, and complications of the two groups were recorded and compared. The knee range of motion and lower limb alignment deviation were recorded before operation and at 6 months after operation, and the knee joint function was evaluated by KSS knee score and function score. RESULTS: There was no significant difference in operation time between the two groups ( P>0.05); the intraoperative blood loss in the robot group was significantly less than that in the traditional group ( P<0.05). Patients in both groups were followed up 6-12 months, with an average of 8.7 months. The incisions of all patients healed well, and there was no postoperative complication such as thrombosis or infection. At 6 months after operation, X-ray examination showed that the position of the prosthesis was good in both groups, and there was no loosening or dislocation of the prosthesis. The knee joint range of motion, the lower limb alignment deviation, and the KSS knee score and KSS function score significantly improved in both groups ( P<0.05) compared to preoperative ones. The changes of lower limb alignment deviation and KSS function score between pre- and post-operation in the robot group were significantly better than those in the traditional group ( P<0.05), while the changes of other indicators between pre- and post-operation in the two groups were not significant ( P>0.05). CONCLUSION Compared to traditional TKA, navigation-free robot-assisted TKA for knee osteoarthritis with extra-articular deformities results in less intraoperative blood loss, more precise reconstruction of lower limb alignment, and better early effectiveness. However, long-term effectiveness require further investigation.
Humans ; Arthroplasty, Replacement, Knee/methods* ; Osteoarthritis, Knee/surgery* ; Robotic Surgical Procedures/methods* ; Male ; Female ; Retrospective Studies ; Range of Motion, Articular ; Middle Aged ; Aged ; Treatment Outcome ; Osteotomy/methods* ; Knee Joint/physiopathology* ; Operative Time

OBJECTIVE: To explore effectiveness of TiRobot-assisted screw implantation in the treatment of coracoid process fractures of the scapula. METHODS: A retrospective analysis was conducted on the clinical data from 24 patients with coracoid process fractures of the scapula admitted between September 2019 and January 2024 and met selection criteria. Among them, 12 patients underwent TiRobot-assisted screw implantation (robot group) and 12 underwent manual screw implantation (control group) during internal fixation. There was no significant difference ( P>0.05) in baseline data such as gender, age, body mass index, disease duration, cause of injury, coracoid process fracture classification, and proportion of patients with associated injuries between the two groups. The incision length, operation time, intraoperative blood loss, hospital stay, accuracy of screw placement, coracoid process fracture healing time, and complications were recorded and compared, as well as pain visual analogue scale (VAS) score, and Constant-Murley score at last follow-up. RESULTS: The intraoperative blood loss and incision length in the robot group were significantly lower than those in the control group ( P<0.05); however, there was no significant difference in operation time and hospital stay between the two groups ( P>0.05). All patients were followed up 8-27 months (mean, 17.5 months), and the difference in follow-up time between the two groups was not significant ( P>0.05). At last follow-up, the VAS score for shoulder pain in the robot group was signifncatly lower compared to the control group, and the Constant-Murley score was significantly higher ( P<0.05). In the robot group, 16 screws were implanted intraoperatively, while 13 screws were implanted in the control group. Radiographic re-evaluation showed that the excellent and good rate of screw implantation was higher in the robot group (93.8%, 15/16) than in the control group (61.5%, 8/13), but the difference in the precision of screw implantation between the two groups was not significant ( P>0.05). Four patients in the robot group and 1 in the control group achieved double screws fixation; however, the difference in achieving double screws fixation between the two groups was not significant ( P>0.05). All fractures healed in both groups with 1 case of malunion in the control group. There was no significant difference in healing time between the two groups ( P>0.05). During follow-up, 1 patient in the control group experienced screw loosening and displacement. There was no significant difference in the incidence of screw loosening and fracture malunion between the two groups ( P>0.05). CONCLUSION Compared with manual screw implantation, TiRobot-assisted minimally invasive treatment of coracoid process fractures of the scapula can reduce intraoperative blood loss, shorten incision length, alleviate pain, and obtain better promote shoulder joint functional recovery.
Humans ; Male ; Female ; Retrospective Studies ; Fracture Fixation, Internal/instrumentation* ; Minimally Invasive Surgical Procedures/instrumentation* ; Adult ; Middle Aged ; Fractures, Bone/surgery* ; Bone Screws ; Coracoid Process/surgery* ; Robotic Surgical Procedures/methods* ; Scapula/surgery* ; Treatment Outcome ; Operative Time ; Young Adult ; Length of Stay ; Blood Loss, Surgical