Abstract Objectives Neoadjuvant chemotherapy (NACT) is commonly incorporated into the management of resectable locally advanced gastric cancer. However, survival outcomes in patients who remain classified as pathological stage IIIC after surgery, particularly when analyzed according to NACT exposure, are not well characterized. This study compares overall survival (OS) according to prior NACT exposure among patients who ultimately remained classified as pathological stage IIIC after curative surgery. Methods This retrospective study included patients who underwent curative surgery between 2010 and 2022 and were diagnosed with pathological stage IIIC gastric cancer on postoperative histopathological examination. Patients were grouped according to whether they received NACT. OS was measured from surgery to death from any cause or last follow-up. Survival was analyzed using the Kaplan–Meier method and Cox proportional hazards regression. Results The study cohort comprised 75 patients, of whom 24.0 % (18/75) received NACT. OS did not differ significantly between patients who received NACT and those who did not, as assessed by the log-rank test (p=0.749). In multivariable Cox regression analysis, NACT was not identified as an independent factor associated with OS (HR: 0.96; 95 % CI: 0.50–1.84; p=0.902). Conclusions Within the limitations of this retrospective study, overall survival was comparable according to neoadjuvant chemotherapy status among patients who ultimately remained classified as pathological stage IIIC after curative surgery. These findings should be interpreted cautiously because the compared groups represent biologically distinct populations and the study was not designed to evaluate the therapeutic efficacy of neoadjuvant chemotherapy.
Abstract Objectives The aim of this prospective data analysis was to evaluate the patient reported quality of postoperative recovery in patients undergoing elective minimally invasive colorectal surgery and to assess the impact of a ERP (Enhanced Recovery After Surgery Protocol) compared to traditional perioperative care. Methods 158 patients undergoing elective colorectal surgery were prospectively enrolled. The first 28 patients were treated during 3 months of ERP development and received standardized traditional care. The following 130 patients were treated under optimized perioperative management with an ERP. Quality of recovery was assessed using the validated QoR-15 questionnaire on postoperative days 2 and 5. Secondary outcomes included the pre- and postoperative length of hospital stay. The functional recovery, compliance to ERP and postoperative mobilization times were also measured. Results Patients in the ERP group showed significantly higher QoR-15 scores on both postoperative day 2 and day 5 compared to the traditional care group indicating a better quality of patient perceived recovery. The duration of initial intensive care observation, the time until removal of the urinary catheter, first bowel movement and until regaining autonomy were all significantly reduced in patients treated according to the ERP. Similarly, mobilization times on the day of surgery as well as on postoperative days 1–3 were significantly longer in the ERP group, indicating earlier and more consistent patient activity. These findings reflect a faster restoration of physiological function and independence The ERP group also had a shorter median length of stay (6 vs. 8 days) correlating with a faster functional recovery. Conclusions Implementation of an ERP in elective colorectal surgery significantly improves patient-reported quality of recovery, accelerates functional recovery and reduces length of hospital stay. Key determinants of early postoperative recovery were the baseline recovery status and the occurrence of postoperative complications, whereas demographic or procedural variables appeared to have less impact.
Objectives: Numerous studies have demonstrated that compliance to surveillance protocols after endovascular aneurysm repair (EVAR) diminishes over time. Additionally, the survival benefit of strict adherence to surveillance is unclear. This study aimed to evaluate compliance and long-term mortality following EVAR. Methods: We conducted a retrospective analysis of all EVAR patients (n=310) with expected follow-up treated between 01/2008 and 12/2020. Demographic data and potential risk factors for non-compliance were analyzed. Compliance was defined as verified follow-up at a maximum interval of 15 months. Results: Overall, 118 patients (38.1 %) died during follow-up. At a median follow-up of 14 [IQR 2, 41] months, 40.3 % of patients were compliant to the follow-up regimen. The presence of endoleak did not significantly influence compliance (p=0.246), but compliance was linked to a higher risk of detected endoleak and reinterventions (p<0.01; p<0.001). Age, sex, marital status, assessed comorbidities, AAA diameter, rupture, urgency of the operation and travel distance to the hospital were not associated with compliance to follow-up. A multivariable time-dependent Cox model with compliance as a time-varying covariate showed non-compliance was linked to a lower hazard of death (p<0.001) with a significant time interaction (beta=0.03, p<0.001), indicating a time-varying effect. The Kaplan-Meier analysis found no difference in survival between groups (p=0.105). Conclusions: Our study showed no survival benefit for patients compliant to follow-up after EVAR. Competing risks analyses revealed higher rates of endoleaks and reinterventions among compliant patients reflecting more intensive surveillance and detection.
Abstract We present the neuro-symbolic anatomy engine, a novel artificial intelligence architecture that integrates structured anatomical knowledge with neural pattern recognition for comprehensive human anatomy modeling. Rather than focusing on individual procedures, the anatomy engine represents a Copernican shift: it encodes a universal model of human anatomy from which any surgical procedure can be simulated. This hybrid approach combines symbolic reasoning over anatomical relationships with neural network processing of text, images, and medical data. It enables transparent, traceable decision-making suited to surgical and educational applications. The system addresses critical limitations in current surgical training and has the potential to support lifelong learning, expand access to complex procedures, and drive surgical innovation.
Autologous microsurgical breast reconstruction remains a cornerstone in complex reconstructive surgery. Since Holmström’s pioneering description of the first free TRAM flap, continuous advancements in diagnostic tools, such as 3D imaging and perforator mapping, have significantly enhanced surgical outcomes. This article also explores the integration of robotic surgery, initially developed for military and NASA applications, now widely adopted in minimally invasive procedures with systems like the Da Vinci robot. Emerging 3D imaging technologies, including AI-supported vascular anatomy visualizations, surface renderings, 3D-printed anatomical models, and cinematic vascular renderings, have contributed to intraoperative problem-solving. Additionally, the latest developments in preoperative, intraoperative, and postoperative applications of artificial intelligence are examined. In conclusion, this article highlights the growing role of AI in breast reconstruction and its future potential to revolutionize the field.
Objectives Giant omphaloceles present a particular challenge in surgical management due to the pronounced abdominal-visceral mismatch and frequently associated comorbidities.Case presentation We report the case of a school-aged child following failed primary closure of a giant omphalocele in the neonatal period. Due to severe loss of domain and extensive adhesions, conventional reconstructive strategies were not feasible. A delayed abdominal wall reconstruction using a vertical dynamic fascial traction system (Fasciotens (R)) was performed to achieve gradual fascial approximation. Despite the need for temporary patch interposition, progressive domain adaptation allowed for subsequent definitive fascial closure.Conclusions This case demonstrates that traction assisted reconstruction can serve as a viable option within an individualized treatment strategy for delayed abdominal wall closure in selected pediatric patients.
Objectives: This study evaluates surgical cases from the past decade involving patients with suspected venous thrombosis (portal vein, hepatic veins, vena cava), hepato cellular carcinoma, and surgical intervention. Methods: A retrospective analysis used data from the Uni versity Hospital Frankfurt from January 2011 to February 2023. Clinical data were extracted from electronic health re cords, including demographic information, tumor character istics, treatment approaches and postoperative outcome. Statistical analysis was performed using SPSS. Results: A total of eight patients were included. The collected data provided insights into the types of vascular invasion, 37.5% pathological venous infiltration, 37.5% with portal vein thrombosis and 25% with intrahepatic vein and atrial tumor thrombus. Surgical interventions included 25% left and 37.5% right hemihepatectomies. 37.5% of surgeries involved thrombus resection. Postoperative complications were Grade IIIa 25%, Grade IIIb 12.5% and Grade IVb 37.5% according to the Clavien-Dindo (CD) classification. Long term follow-up revealed a Grade V complication in one pa tient. The median overall survival (OS) was 4.95 years post-surgery. The respective 1, 3 and 5-year survival rates were 87.5, 58.3 and 38.9%. The disease-free survival (DFS) was 5 months in patients 1-6 and the progression-free survival (PFS) in patients 7 and 8 was 3.7 and 3.63 months. Conclusions: This study highlights the complexities and potential benefits of surgical intervention in patients with HCC and venous thrombosis. Despite the small sample size, the findings contribute valuable information for refining surgical indications and improving interdisciplinary decision-making processes. Surgery in this patient popula tion is feasible with 87.5% 1-year survival rate.
Objectives Lymphovenous anastomosis (LVA) is an established standard of care in the surgical treatment of secondary lymphedema, especially of the lower limbs. However, objective postoperative evaluation remains challenging. Ultrasound elastography offers a quantitative evaluation tool for the assessment of tissue stiffness and may be employed for the detection of subtle postoperative changes in this context. Methods 12 consecutive patients with primary or secondary lower-limb lymphedema were enrolled in a pilot, prospective observational study with pre- and postoperative elastography and volumetric assessment within the scope of LVA treatment. All measurements were carried out at predefined anatomical regions using a fixed transducer setup to minimise operator bias. Results A trend toward postoperatively reduced calf stiffness was observed (-2.31 kPa; p=0.066, r=0.54). Additionally, we report significant changes in stiffness symmetry between healthy and affected thighs after LVA surgery (p=0.037, Cohens d -0.685 [95 %CI -1.105 to -0.040]). Postoperative changes in thigh and knee circumference correlated with elastography parameters (rho=0.625-0.741; p <= 0.030), while volumetric differences were not statistically significant. Conclusions Ultrasound elastography may offer an adjunct for the detection of early, subclinical tissue remodelling following LVA surgery. Given its pilot study nature, these findings suggest a potential role for elastography as a complement to conventional measurements and more objective monitoring of surgical outcomes in lymphatic surgery.
Objectives: Robotic assisted minimally invasive esophagectomy (RAMIE) has demonstrated advantages over open esophagectomy, including reduced morbidity and comparable oncological outcomes. However, predicting which patients achieve a "perfect outcome" remains unclear. This study evaluates postoperative outcomes in RAMIE patients and identifies parameters associated with an uncomplicated recovery in a German high-volume center. Methods: We conducted a retrospective analysis of 249 RAMIE cases performed between April 2017 and January 2023. Patients were divided into two groups: Clavien-Dindo grade 0(n=87) and Clavien-Dindo>0(n=162). Preoperative demographics, intraoperative metrics, and postoperative outcomes were compared. Key postoperative metrics included ICU/hospital stay duration, removal of catheters, initiation of oral feeding, and C-reactive protein (CRP) levels on postoperative days (POD) 3, 5, and 7. Results: No significant differences were found in preoperative factors. Intraoperative parameters, including operative time and single-lung ventilation duration, were similar between groups. CRP levels were significantly lower in complication-free patients on POD3 (105.7 vs. 132.6 mg/L; p=0.0009), POD5 (66.0 vs.130.0 mg/L; p<0.0001), and POD7 (44.1 vs. 111.4 mg/L; p<0.0001). Patients with a perfect outcome had earlier removal of peridural catheters (POD6 vs.POD8; p=0.0021), chest drains (POD6 vs. POD7; p=0.0009), and initiation of oral feeding (POD6 vs. POD9; p<0.0001). Importantly, 66 % of complications occurred before POD6. Conclusions: A perfect outcome following RAMIE is associated with earlier catheter removal, and oral feeding initiation by POD6, alongside CRP levels below 70 mg/L. The sixth postoperative day appears pivotal for predicting outcomes, as complications predominantly manifest before this timeframe. These findings highlight the importance of targeted postoperative management to identify low-risk patients suitable for early discharge, improving recovery and resource utilization.
Objectives Fetal lower urinary tract obstruction (LUTO) has been demonstrated to be associated with significant morbidity and mortality. As a result, vesicoamniotic shunts are placed prenatally to relieve the urinary tract. The aim of this study was to evaluate the postnatal complications of prenatal vesicoamniotic shunt placement and the need for pediatric surgical intervention.Methods The retrospective study included all male patients with LUTO, and prenatal intervention treated at the Department of Pediatric Surgery and Pediatric Urology, University Hospital Marburg, between January 1st, 2013, and December 31st, 2022. In addition to the demographic data, the complications due to the prenatal intervention and the postnatal pediatric surgical treatment due to the complication were evaluated.Results A total of 23 male infants were included in the study. In 22/23 patients (96 %), a vesicoamniotic shunt was placed. In one case, only amniotic fluid refilling was performed. Shunt-related complications were frequently observed, with dislocation occurring in 68 % of cases and abdominal wall defects in 21 %. Postnatal management proved to be a complex undertaking, with the majority of patients requiring surgical intervention for implant removal. Of these patients, 78 % underwent laparotomy or laparoscopy. The presence of vesicoperitoneal and vesicorectal fistulas, renal and ureteral injuries, and bowel perforations often necessitated immediate surgical intervention. Despite the implementation of early decompression efforts, a significant proportion of patients exhibited the development of chronic kidney disease, with a notable percentage requiring peritoneal dialysis (57 %) and a considerable number undergoing kidney transplantation during subsequent follow-up (22 %).Conclusions Prenatal intervention for LUTO is associated with high rates of peri- and postnatal complications, frequent need for surgical intervention, and poor long-term renal outcomes. These findings support the need for improved prenatal counseling, technical innovation, and multidisciplinary postnatal management to optimize care for affected infants.
Objectives Emergency surgery is a key component of surgical training. Intestinal obstruction due to adhesions is a common emergency in general surgery that often requires complex and individualized adhesiolysis. Despite its clinical relevance, little is known about surgical trainee involvement in these procedures. This study examines the frequency of trainee participation in emergency adhesiolysis and compares short-term outcomes with those of board-certified surgeons.Methods This retrospective cohort study analyzed 333 patients who underwent emergency adhesiolysis for adhesive small bowel obstruction between 2003 and 2020. Propensity score matching (1:1) was performed based on the procedure, diagnosis, age, and American Society of Anesthesiologists (ASA) score. Logistic regression analyses were used to identify factors associated with postoperative complications (CDC >= 3).Results Among the 333 procedures, 47 were performed by supervised trainees, and 286 were performed by board-certified surgeons. After matching, 76 patients were included in the final analysis. Baseline characteristics were comparable between the groups. The operative time was significantly shorter in the trainee group (p=0.005) with no significant differences in intra- and postoperative complications or 30-day mortality. In multivariable regression, ASA score (OR 2.56; 95 % CI 1.28-5.13; p=0.008) and age (OR 1.04; 95 % CI 1.01-1.08; p=0.012) were identified as independent risk factors for complications.Conclusions Our findings suggest that emergency adhesiolysis can be performed by advanced surgical trainees under appropriate supervision and is not associated with increased postoperative morbidity. However, trainee involvement in such procedures remains limited.
Objectives:The orthoplastic approach has emerged as the gold standard in the reconstruction of complex extremity injuries. While robot-assisted microsurgery (RAMS) enhances precision and ergonomics, its role in the challenging orthoplastic setting remains largely unexplored. This study aimed to evaluate our initial institutional experience with robot-assisted free flap reconstruction for complex limb injuries within an orthoplastic approach. Methods:From February 2023 to February 2025, we prospectively collected data on patients with combined traumatic bone and soft tissue injuries undergoing robot-assisted free flap transfer to the extremities. Data included patient demographics, surgical details (e.g., operating times, anastomosis/coaptation duration), and complications. Ethical approval was obtained. Results:Our cohort of 18 patients (78 % male, mean age 50.3 years) received free flaps for traumatic soft tissue defects (78 % lower extremity). The ALT flap was most commonly used (67 %). Mean operating time was 353.0 min. 19 anastomoses and coaptations were performed, with no conversions to conventional techniques. A major complication (arterial thrombosis) occurred in one case, successfully salvaged with conventional re-anastomosis, resulting in no complete flap losses. There was one partial flap loss. Three minor complications (delayed wound healing, 17 %) were observed. Conclusions:Our experience shows the feasibility of RAMS in orthoplastic limb reconstruction. Further studies are needed to validate these findings and define the optimal role and benefits of RAMS in orthoplastic surgery.
Objectives Symmetrical peripheral gangrene (SPG) is a rare condition characterized by symmetrical gangrene affecting the acral regions of two or more extremities, without the presence of major vessel obstruction. The precise pathophysiology of SPG is unclear, but it is believed to involve various biochemical pathways and is often associated with vasopressor therapy. Despite various therapeutic attempts, there is no established standard treatment for SPG.Methods This study evaluated the efficacy of locally administered phentolamine, an alpha-receptor antagonist, in four critically ill patients undergoing catecholamine therapy and presenting with SPG. Tissue perfusion was assessed using clinical observation and indocyanine green-assisted laser angiography before and after phentolamine administration.Results All four patients demonstrated immediate improvement in tissue perfusion following phentolamine application, as evidenced by angiography. No amputations were necessary. The patients' clinical outcomes suggest that phentolamine effectively counteracts vasopressor-induced ischemia.Conclusions Phentolamine offers a targeted therapeutic approach for vasopressor-induced SPG by mitigating vasoconstriction without systemic side effects. Its incorporation into clinical practice requires further validation to optimize its application and efficacy.
Objectives This study proposes a dual-pathway framework for AI-supported decision-making in OMFS on the background of heterogeneous data sources, varying clinical experience, and inconsistent integration into medical classification systems. The approach targets (I) the classification of findings, symptoms, treatments in general hospitals to guide triage and referral, and (II) individualized risk assessment and surgical planning in tertiary centers, with (III) intraoperative execution supported by 3D and mixed/augmented/extended reality (MR/AR/XR) technologies.Methods Using structured data, exploratory data analysis (EDA), machine learning, and large language models (LLMs), the system generates context-aware risk predictions and personalized treatment recommendations. Clinical and imaging data (MDCT, CBCT, MRI) are harmonized and modeled. These are translated into assessment and operative workflows using additive manufacturing, MR/AR/XR. The framework improves diagnostic consistency, enables earlier triage, enhances surgical reproducibility and is designed for scalability, multilingual use, and interoperability across healthcare systems.Results The described workflow was proved to be technically feasible and clinically coherent. Structured integration of retrospective clinical data enabled stable semantic harmonization and accurate temporal modeling. ML-models trained on these datasets achieved reliable complication prediction in mandibular trauma. The operational translation 3D-planning into surgical practice using printed guides and MR-visualization demonstrated high accuracy in procedures and supported reproducible intraoperative execution. These results show that AI-derived diagnostics, predictive modelling and augmented surgical workflows can be integrated into an OMFS pathway.Conclusions This AI-based concept addresses diagnostic and procedural gaps in OMFS, supporting both peripheral care providers and surgical specialists and lay a foundation for an ethically grounded and globally applicable surgical decision support system.
Objectives This study examines the clinical application of interdisciplinary reconstructive strategies for complex forearm and hand defects. Emphasis is placed on principles guiding flap selection, anatomical localization, and the central role of plastic surgeons within coordinated surgical teams. The aim is to clarify how collaborative planning and technique adaptation influence reconstructive outcomes in upper extremity salvage.Methods A retrospective review was conducted of 79 patients who underwent upper extremity reconstruction between 2020 and 2024 at a tertiary care center. Inclusion required composite defects of the hand or forearm treated with local, regional, or free flaps. Demographics, etiology, defect location, reconstructive technique, interdisciplinary collaboration, and complications were analyzed descriptively.Results Most patients were male (n=62), with a mean age of 53.3 years. Defects most often involved the long fingers (n=32) and thumb (n=31). Trauma (68 %) was the main cause, followed by oncologic resection (22 %) and infection (10 %). Free flaps (n=15) were primarily used for larger or composite defects requiring microsurgical reconstruction, while local and regional flaps were employed zone-specifically for smaller soft tissue defects, especially in digits and thumb. Functional reconstruction addressed tendon, nerve, vessel, and bone injuries. The overall complication rate was 12.6 %, with no flap failures or limb loss.Conclusions Upper limb reconstruction benefits from individualized, anatomy-driven planning and interdisciplinary cooperation. Plastic surgeons play a key role in adapting techniques to anatomical zones, achieving favorable functional and aesthetic outcomes.
Introduction:Musculoskeletal tissues, including bone, tendon, cartilage, and muscle, are vital for movement and structural support, yet, their repair after injury remains a significant clinical challenge. Their regeneration relies on complex molecular signaling that regulates inflammation, repair, and remodeling. Understanding these cues, offers opportunities to design targeted therapeutic strategies. Content:This review summarizes current evidence on molecular regulators of musculoskeletal tissue regeneration with emphasis on both shared and tissue-specific mechanisms across bone, tendon, cartilage and muscle. Key molecular cues include growth factors, cytokines, extracellular matrix-derived signals, and non-coding RNAs, particularly microRNAs. Critical pathways such as TGF-β, NF-κB, FGF, and YAP/TAZ can either promote healing or drive pathological fibrosis depending on their modulation. This review discusses therapeutic strategies targeting these molecular cues, including microRNA replacement therapies, small molecules, growth factor delivery, and pathway-specific inhibitors or activators. Summary and Outlook:Understanding how these molecular cues and pathways function and interact to regulate healing and regeneration offers valuable insight into tissue-specific and cross-tissue repair strategies. These advances may support the development of targeted therapies to enhance musculoskeletal regeneration and functional recovery. Furthermore, future research should focus on integrating these molecular insights with biomaterial and mechanobiological approaches to develop next-generation regenerative interventions.
Objectives In the evolving field of surgical education, video-based learning has become increasingly prevalent. "Reels", videos typically under 60 s, have gained traction due to their potential to enhance engagement. Despite their growing popularity, best practice guidelines for reel creation and use in surgical education remain limited. This study aimed to evaluate the educational value of reels in the education of orthopedic and trauma surgeons and to identify key features that contribute to their effectiveness.Methods The Kocher-Langenbeck acetabular approach was video recorded, and two specific procedural steps were edited and peer reviewed to produce two reels. An evaluation questionnaire was distributed to orthopedic and trauma surgeons. The responses were analyzed via descriptive statistics and Moore's outcome levels.Results Among the 178 respondents (6.8 % response rate), 148 completed the full survey. The respondents, practicing in 55 countries, had diverse levels of surgical experience. Scores across Moore's outcome levels were high, with 86.0 % participation and strong overall satisfaction, with 96.0 % finding the reels clear and effective and 94.5 % indicating a willingness to integrate them into daily practice. Learning was rated 4.21/5 and 4.41/5. Surgeons expressed interest in the future use of reels and suggested enhancements, including clearer anatomical labels, smoother transitions, and integration with full-length content on established educational platforms.Conclusions Reels offer value in surgical education. When thoughtfully designed and embedded within sound educational frameworks, they can enhance knowledge acquisition and support clinical learning. These findings affirm the value of further developing and integrating short video formats into surgical education curricula.
Objectives The application of 3D-based methods for deformity correction of the upper extremity, including patient-specific instruments (PSIs), is attracting increasing attention in clinical practice and requires the collaboration of orthopaedic surgeons and medical engineers.Methods The management of various elbow deformities using 3D-based surgical methods, including PSIs, is presented. A narrative literature review with a defined search strategy using PubMed as a database was conducted to identify further applications around the elbow that have been published to date.Results This case series presents with one case each the correction of the following deformities: cubitus varus, dorsal radial head subluxation, translational deformity of the distal humerus, cubitus valgus (CVL) and radial head dislocation in hereditary multiple exostoses (HME). The Supplementary literature with 28 studies presents further deformities that were corrected on a 3D basis: intra-articular fracture of the capitulum radii, extension deformity of the distal humerus and malunited radial neck fractures. These 3D-based procedures have been used most frequently to correct cubitus varus and are superior to conventional methods in terms of accuracy in comparative studies.Conclusions The application of 3D-based planning methods, including PSIs use, offers excellent opportunities and accuracy for corrective osteotomies around the elbow. In addition to the correction of cubitus varus, extension to the correction of chronic dislocation of the radial head after Monteggia fracture and HME appears promising. The future implementation of 3D-based planning based on magnetic resonance imaging (MRI) would be highly desirable.
Objectives The relation of objective measures of olfactory function and health-related quality of life (HRQoL) in patients with pituitary adenoma after endoscopic transsphenoidal surgery is not well investigated yet. We examined HRQoL of pituitary adenoma patients pre- and postsurgery, in addition to olfactory performance as an objective measure of sinonasal health.Methods Thirty patients with pituitary adenoma were included in this prospective observational study. They completed the Sniffin' Sticks test as well as measures of HRQoL before and after bi-nostril endoscopic transsphenoidal surgery.Results Olfactory performance and HRQoL were correlated in the physical (rs=0.462, p=0.010) but not in the psychological HRQoL domain. While psychological HRQoL tended to ameliorate after surgery (Z=-1.94, p=0.052), physical HRQoL did not. Preoperative physical HRQoL predicted olfactory performance after surgery with an explained variance of 24.9 %, representing a moderate to strong effect; age did not significantly add to the explained variance.Conclusions In our study, physical HRQoL before surgery of pituitary adenomas as a subjective measure of well-being was highly relevant for objective sinonasal outcome. This finding reinforces the value of preoperative HRQoL assessment as a predictor of postoperative patient health, adding to the benefits of minimally invasive surgical techniques.
