Comparison of Treatment Options for Chronic Scapholunate Interosseous Ligament (SLIL): A Systematic Literature Review and Meta-Analysis.

Background: The scapholunate interosseous ligament (SLIL) is an important contributor to wrist stability and functionality. SLIL injury is debilitating and therefore many surgical techniques have been proposed, but the optimal treatment modality remains debated.This meta-analysis reviews the available literature comparing surgical techniques used in the treatment of chronic SLIL to determine the best approach. Methods: An electronic search of the literature was conducted to identify all randomized controlled trials and cohort studies published before January 2019 that evaluated clinical outcomes of capsulodesis reconstruction, the modified Brunelli technique, and the reduction and association of the scaphoid and lunate (RASL) procedure for treatment of chronic SLIL. A chi-square analysis was performed to identify possible differences between each technique for several outcome measures. Results: A total 20 studies encompassing 409 patients met inclusion criteria. Average age among patients was 36.7 years, and 68.2% of patients were male. Reductions in visual analog scale pain scale; Disabilities of Arm, Shoulder, and Hand (DASH) scores; and increases in grip strength and range of motion were observed for all techniques. Capsulodesis was superior to the modified Brunelli technique regarding preserved range of motion. Conclusions: No significant differences were observed among any of the techniques for pain, DASH score, and grip strength outcomes. Capsulodesis, modified Brunelli, and RASL surgical techniques for the treatment of chronic SLIL injuries may all be seen as reliable methods of treatment of chronic SLIL injuries. While future trials directly comparing these methods are needed, this study suggests there is no superiority of one technique over another.

Cemented-augmented fixation of metastatic humeral lesions without segmental bone loss results in reliable outcomes.

Background: Treatment of metastatic lesions to the humerus is dependent on patient's pain, lesion size and location, and post-operative functional goals. Surgical options include plate or nail fixation [open reduction internal fixation (ORIF)], or endoprosthetic replacement (EPR), with cement augmentation. The objective of this study was to perform a single institution retrospective analysis of outcomes by method of reconstruction, tumor volume, and pathologic diagnosis. Methods: The records of 229 consecutive patients treated surgically for appendicular metastatic disease from 2005-2018 at our musculoskeletal oncology center were retrospectively reviewed following institutional review board (IRB) approval. Indications for surgical treatment at the humerus included patients who presented with impending and displaced pathologic fractures. Results: Sixty patients (34 male, 26 female) with a mean age of 62.9±12.2 were identified who were treated surgically at the proximal (n=21), diaphyseal (n=29), or distal (n=10) humerus. Forty-nine (82%) patients presented with displaced pathologic fractures. The remaining eleven patients had a mean Mirels score of 9.5. There was no difference in overall complication rate between EPR or ORIF [4/36 (11%) versus 2/24 (8%); P=0.725]. Mean Musculoskeletal Tumor Society (MSTS) scores were 83% for both EPR and ORIF, with no differences in subgroup analyses at the proximal, diaphyseal, or distal humerus. Patients with cortical destruction on anterior posterior (AP) and lateral imaging were at increased risk for mechanical failure [2/6 (33%) versus 0/18 (0%), P=0.015]. Conclusions: In conclusion, when pathologic pattern permits, cement-augmented fixation allows for stabilization of pathologic bone, while minimizing risk of soft-tissue detachment, while EPR resulted in similar outcomes in patients with more extensive bone destruction. Increased tumor volume was associated with lower MSTS scores.

Management of Large Segmental Bone Defects at the Knee With Intramedullary Stabilized Antibiotic Spacers During Two-Stage Treatment of Endoprosthetic Joint Infection.

BACKGROUND: Following debridement of infected prostheses that require reconstruction with an endoprosthetic replacement (EPR), instability related to segmental residual bone defects present a challenge in management with 2-stage reimplantation. METHODS: We retrospectively reviewed all patients treated for revision total joint or endoprosthetic infection at the knee from 1998 to 2018. At our institution, patients with skeletal defects >6 cm following explant of prosthesis and debridement (stage 1) were managed with intramedullary nail-stabilized antibiotic spacers. Following stage 1, antimicrobial therapy included 6 weeks of intravenous antibiotics and a minimum of 6 weeks of oral antibiotics. Following resolution of inflammatory markers and negative tissue cultures, reimplantation (stage 2) of an EPR was performed. RESULTS: Twenty-one patients at a mean age of 54 ± 21 years were treated for prosthetic joint infection at the knee. Polymicrobial growth was detected in 38% of cases, followed by coagulase-negative staphylococci (24%) and Staphylococcus aureus (19%). Mean residual skeletal defect after stage 1 treatment was 20 cm. Prosthetic joint infection eradication was achieved in 18 (86%) patients, with a mean Musculoskeletal Tumor Society score of 77% and mean knee range of motion of 100°. Patients with polymicrobial infections had a greater number of surgeries prior to infection (P = .024), and were more likely to require additional debridement prior to EPR (odds ratio 12.0, P = .048). CONCLUSION: Management of large segmental skeletal defects at the knee following explant using intramedullary stabilized antibiotic spacers maintain stability and result in high rates of limb salvage with conversion to an endoprosthesis.

Do pediatric shoulder fractures benefit from surgery?

PURPOSE OF REVIEW: We aimed to review considerations, current treatment options, and complications in the management of pediatric proximal humerus fractures. RECENT FINDINGS: Recent literature has shown an increased incidence of operative management of proximal humerus fractures. With increased age, and increased deformity, studies report excellent outcomes after operative treatment. Still, patients under the age of 12 and with Neer grade I and II fractures are consistently treated nonoperatively. SUMMARY: Indications for operative management of proximal humerus fractures in skeletally immature patients have become increasingly widened. Current literature emphasizes the stratification of patients based on displacement, angulation, and shortening, with overall positive outcomes. Each case should be considered on individual bases, accounting for both radiographic parameters, developmental stages of patients, and potential complications. In the authors' opinion, adolescent patients with Neer Horowitz 3 and 4 fractures surgical management should be considered. In younger patients with nonoperative management, even with significant displacement, is the mainstay of treatment because of the tremendous remodeling potential of the proximal humerus in children. VIDEO ABSTRACT: http://links.lww.com/MOP/A56.

Epidemiology and survival of liposarcoma and its subtypes: A dual database analysis.

PURPOSE: Liposarcoma (LPS) is a one of the most commonly diagnosed soft tissue sarcomas. Little is known about the epidemiology and prognosis of each subtype. We present an analysis of epidemiology and survival of the subtypes of LPS using a national database. METHODS: We queried the Survival Epidemiology, and End Results (SEER) and the Canadian Institute for Clinical Evaluative Sciences (ICES) databases for data on 7 types of LPS. Pearson's chi square was used to determine associations between variables and subtypes. Kaplan-Meier and Cox Regression analyses were performed for two tests: one using SEER data and the other using variables common to both SEER and ICES. RESULTS: The well-differentiated subtype was the most common subtype identified. Metastatic disease was associated with decreased survival across all subtypes and age >35 was associated with decreased survival in well-differentiated and myxoid subtypes. Tumor grade was associated with decreased survival in the well-differentiated, myxoid, mixed, and round cell subtypes. In the secondary analysis, age >35 was associated with decreased survival in the myxoid subtype. CONCLUSIONS: The prognosis of liposarcoma differs greatly by subtype. Clinicians should account for patient factors at the time of diagnosis to best navigate treatment of their patients.

Effect of Mitomycin C on Recurrence of Ganglion Cysts in the Foot and Ankle.

Ganglion cysts are among the most common benign soft tissue masses. Although surgery has been shown to be effective, ∼12% to 42% of cases with long-term follow-up have been reported to recur. The purpose of this study was to determine the impact of the topical application of mitomycin C used as an adjuvant to surgery on recurrence rate of ganglion cysts. A retrospective analysis was done on all patients surgically treated by 1 surgeon for ganglion cysts. The primary end point was local recurrence after the procedure, determined clinically and by ultrasound. Secondary outcomes included wound complication rate, adverse effects, and overall patient satisfaction. A total of 98 consecutive patients were included in this study and assigned to a study group in a nonrandomized manner. The control group (n = 52) consisted of patients who underwent surgical resection only. The study group (n = 46) consisted of patients who underwent surgical resection with application of topical mitomycin C. No patients were lost to follow-up. Of the 52 patients in the control group, 13 (25.0%) had recurrence of the ganglion cyst. In contrast, in the experimental study group, 2 patients (4.3%) had a recurrence. There was no difference in superficial wound infections between the 2 groups. In this study, we found that the use of topical mitomycin C as an adjuvant to surgical resection significantly reduced the recurrence rate. Wound infection and overall nonrecurrence complication rates were similar to those of other studies.

Four-Corner Arthrodesis Versus Proximal Row Carpectomy for Scapholunate Advanced Collapse: A Systematic Literature Review and Meta-analysis.

BACKGROUND: Scapholunate advanced collapse (SLAC) of the wrist is one of the most common patterns of degenerative arthritis in the wrist. Surgical intervention is warranted for individuals with symptomatic SLAC and degenerative disease that affects the radioscaphoid joint. The most popular options for motion-preserving reconstruction and treatment of this disease include 4-corner arthrodesis and proximal row carpectomy. The purpose of this article was to conduct a systematic literature review and meta-analysis to identify any differences in the clinical outcomes of 4-corner arthrodesis and proximal row carpectomy for the treatment of SLAC. METHODS: An electronic literature search of PubMed, Embase, OVID, and the Cochrane Library was conducted to identify studies evaluating the clinical outcomes of 4-corner arthrodesis versus proximal row carpectomy for the treatment of SLAC. Primary outcome measures included flexion/extension range of motion, grip strength, and level of pain. RESULTS: Eight studies encompassing 311 patients met the inclusion criteria for the meta-analysis. Our meta-analysis indicated that when compared with 4-corner arthrodesis, patients who underwent proximal row carpectomy had statistically significantly increased flexion/extension range of motion by 6.2 degrees, significantly increased grip strength by 1.52%, and reduced level of pain by 0.3. CONCLUSIONS: This study demonstrated that in comparative studies, there was a statistical difference favoring proximal row carpectomy to 4-corner arthrodesis for the treatment of SLAC. Although these differences were statistically significant, they remain very small and lack clinical relevance. This study further supports that both of these treatment options are equivalent for the treatment of this disease. Although not clinically significant, compared with 4-corner arthrodesis, patients treated with proximal row carpectomy had increased range of motion, increased grip strength, and decreased pain. Limitations to these findings are the small number of studies available and the increased heterogeneity between the studies. Further studies need to be conducted to confirm these findings.

Operative Versus Nonoperative Outcomes of Middle-Third Clavicle Fractures: A Systematic Review and Meta-Analysis.

OBJECTIVES: Middle third clavicle fractures have long been managed conservatively with immobilization. Some patients, especially those with completely displaced or shortened clavicle fractures are now thought to have increased risk of nonunion or symptomatic malunion. The authors performed a meta-analysis to study the incidence of nonunion and symptomatic malunion and test the hypothesis that surgical fixation of these fractures significantly lowers the risk of these complications. METHODS: A search was performed in the PubMed, Embase, and Cochrane Library databases for randomized clinical trials and quasi-experimental trials that compare outcomes of operative and nonoperative management for clavicle fractures that are fully (100%) displaced or have greater than 2 cm of shortening. Pooled patient data were used to construct forest plots for the meta-analysis. RESULTS: Eleven studies including 497 patients who were treated and 457 patients treated conservatively were analyzed. Patients managed operatively had significantly lower relative risk of developing nonunion [0.17 (95% confidence interval 0.08-0.33)] and symptomatic malunion [0.13 (95% confidence interval 0.05-0.37)]. Plate fixation significantly reduced the risk of nonunion, but intramedullary nail fixation did not. There was no difference in Constant-Murley or DASH scores between the 2 treatment groups or in the rate of secondary operative procedures. CONCLUSIONS: Patients who undergo operative fixation of displaced middle-third clavicle fractures have a lower incidence of nonunion and symptomatic malunion. The clinical significance of this effect is uncertain, as functional scores were similar in both groups. Further research into the risk factors for nonunion and symptomatic malunion will be necessary to determine which patients benefit from operative fixation. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Epidemiology, Incidence, and Survival of Rhabdomyosarcoma Subtypes: SEER and ICES Database Analysis.

Rhabdomyosarcoma is the most common soft-tissue sarcoma in children and adolescents and accounts for 3% of all pediatric tumors. Subtypes include alveolar, spindle cell, embryonal, mixed-type, pleomorphic, and rhabdomyosarcoma with ganglionic differentiation. The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database was queried for patients diagnosed with any type of rhabdomyosarcoma between 1973 and 2014. Patient demographics, tumor characteristics, and incidence were studied with χ2 analysis. Survival was modeled with Kaplan-Meier survival curves and Cox proportional hazards models were used to assess the effect of age and gender on survival. Pleomorphic subtype had higher grade and larger sized tumors compared to other subtypes (p < 0.05). Pleomorphic and alveolar rhabdomyosarcoma had the worst overall survival with a 26.6% and 28.9% 5-year survival, respectively. Embryonal rhabdomyosarcoma had the highest 5-year survival rate (73.9%). Tumor size was negatively correlated with survival months, indicating patients with larger tumors had shorter survival times (p < 0.05). Presence of higher-grade tumors and metastatic disease at presentation were negatively correlated with survival months (p < 0.05). No significant differences in the survival were found between gender or race between all of the subtypes (p > 0.05). This study highlights key differences in the demographic and survival rates of the different types of rhabdomyosarcoma that can be used for more tailored patient counseling. We also demonstrate that large, population-level databases provide sufficient data that can be used in the analysis of rare tumors. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2226-2230, 2019.

The Incidence of Snow Blower-Related Injuries to the Hand in the United States.

BACKGROUND: Snow blowers represent a highly preventable and increasingly common mechanism of hand injury. This study examines current safety features and their impact on decreasing the incidence of snow blower-related injuries. METHODS: The National Electronic Injury Surveillance System was queried to look for injuries related to the use of snow throwers or blowers between 2001 and 2016. From all of the injuries related to snow blowers, we collected information on identifying characteristics, location of injury, and type of injury (i.e., avulsion). Chi-squared tests were used for categorical variable comparisons, and Student t tests were used for continuous variable comparisons. Data analysis was performed using SAS statistical software, version 9.3 (SAS Institute, Inc., Cary, NC). The Consumer Product Safety Commission's provided SAS algorithm was used to calculate all national injury estimates and variances. Statistical significance was determined based on P < 0.05. RESULTS: Within the study period, there were 3,550 reported injuries. The extrapolated national incidence was 92,799, with an average annual incidence of 5,800 or 1.9 injuries per 100,000 US population per year. The most commonly injured body part was the finger followed by the hand. Most common types of injuries were fractures, lacerations, and amputations. CONCLUSIONS: The incidence of snow blower injuries increased from 2001 to 2016. Unlike with other power tools, Consumer Product Safety Commission-mandated guidelines for safer operation and improvements in equipment have not been successful in producing a decrease in the incidence of snow blower injuries to the upper extremity. Based on this, further equipment modifications are necessary and should be aimed at preventing operators from placing their hand into the exit chute while the machine is still running. Physicians should take an active role in their practice as well as in their professional societies to educate and counsel patients to prevent further injury.

Complications following allograft reconstruction for primary bone tumors: Considerations for management.

INTRODUCTION: The aim of this study was to investigate complication rates and types following allograft reconstruction and discuss unique considerations for management. METHODS: Seventy-four consecutive patients underwent large segment allograft reconstruction following resection of primary musculoskeletal tumors from 1991 to 2016. Mean patient age was 32 ±â€¯20 years (range, 5-71 years). Minimum follow-up was 2 years unless patients were lost to disease prior. Mean follow-up was 105 months. RESULTS: Thirty-five patients had complications requiring subsequent surgery at a mean of 30 months (range, 1-146 months) post-operatively. Individual complication rates were 29%, 50%, and 42% for Allograft Prosthetic Composite, Intercalary, and Osteoarticular allograft reconstruction, respectively. Risk factors for complication included age less than 30 (OR 4.5; p = 0.002), male gender (OR 2.8; p = 0.031), chemotherapy (OR 4.4; p = 0.003), lower extremity disease (OR 3.4; p = 0.025). In patients with complications, limb-retention rate was 91% and mean MSTS scores were 23.6. CONCLUSION: Despite considerable complication rates, management with a systematic approach results in successful outcomes with limb-retention greater than 90% and mean MSTS scores of 79%. In carefully selected patients, allografts provide a reliable method of reconstruction with treatable complications occurring at a mean of 30 months.

Platelet rich plasma for photodamaged skin: A pilot study.

INTRODUCTION: Despite increasing popularity of platelet-rich plasma (PRP) in treating aging facial skin, the quality of evidence supporting its use is poor due to the lack of consistent methods of its preparation and application. OBJECTIVE: This study was conducted to assess treatment efficacy and patient satisfaction with a single PRP treatment prepared with a simplified preparation and application technique. METHODS: Four millilitre of PRP were injected into 6 standardized points on each side of the face. Outcomes were assessed by independent physician evaluation of pretreatment and posttreatment photographs using the Wrinkle Severity Rating Scale (WSRS) and Global Aesthetic Improvement Scale (GAIS). In addition, patient-reported outcomes were evaluated using the FACE-Q. RESULTS: Thirty-one participants ranging from 27 to 71 years of age (median, 38; IQR 32-58) were recruited for this study. Posttreatment WSRS scores improved in only 1 patient; the GAIS scores of 14 patients indicated aesthetic improvement. Analysis of FACE-Q scores revealed statistically significant increases in participant satisfaction with overall facial appearance and cheeks. The most frequently reported adverse effects were tenderness (23.4%; 7 of 31), facial tightness (20.0%; 6 of 31), and swelling (20.0%; 6 of 31). CONCLUSIONS: A simple method of PRP preparation offers modest benefit in treating the effects of skin aging and photodamage. Future research studies should alter our methods using a stepwise approach to optimize the treatment of aging facial skin with PRP.

Assessing Quality of Life and Patient-Reported Satisfaction with Masculinizing Top Surgery: A Mixed-Methods Descriptive Survey Study.

BACKGROUND: Masculinizing top surgery (bilateral mastectomy with chest wall reconstruction) is an important gender-affirming procedure sought by many transmasculine and nonbinary individuals. Current literature is focused primarily on details of surgical technique and complication rates, with limited data available on how top surgery affects subjective quality-of-life measures. METHODS: An anonymous online survey was distributed to 81 of the senior author's former top-surgery patients. The survey response rate was 72 percent (58 respondents). Responses were analyzed to investigate quality of life, sexual confidence, mental health, satisfaction with top surgery, and patient attitudes toward top surgery's role in gender affirmation. RESULTS: Following top surgery, measures of quality of life and sexual confidence improved significantly (p < 0.001). In addition, 86 percent reported improvement in gender dysphoria-related mental health conditions. All but one respondent reported that top surgery had an overall positive impact on their life. CONCLUSIONS: Top surgery had major positive effects on all mental health and quality-of-life metrics. The authors' findings contribute to a much-needed body of evidence that top surgery markedly improves the daily lives and functioning of transgender and nonbinary individuals who choose to undergo it.

Current status of simulation training in plastic surgery residency programs: A review.

Increased emphasis on competency-based learning modules and widespread departure from traditional models of Halstedian apprenticeship have made surgical simulation an increasingly appealing component of medical education. Surgical simulators are available in numerous modalities, including virtual, synthetic, animal, and non-living models. The ideal surgical simulator would facilitate the acquisition and refinement of surgical skills prior to clinical application, by mimicking the size, color, texture, recoil, and environment of the operating room. Simulation training has proven helpful for advancing specific surgical skills and techniques, aiding in early and late resident learning curves. In this review, the current applications and potential benefits of incorporating simulation-based surgical training into residency curriculum are explored in depth, specifically in the context of plastic surgery. Despite the prevalence of simulation-based training models, there is a paucity of research on integration into resident programs. Current curriculums emphasize the ability to identify anatomical landmarks and procedural steps through virtual simulation. Although transfer of these skills to the operating room is promising, careful attention must be paid to mastery versus memorization. In the authors' opinions, curriculums should involve step-wise employment of diverse models in different stages of training to assess milestones. To date, the simulation of tactile experience that is reminiscent of real-time clinical scenarios remains challenging, and a sophisticated model has yet to be established.

The Effect of Processing Technique on Fat Graft Survival.

BACKGROUND: Wide variations in fat graft survival have been reported. The authors hypothesize that treating the adipose tissue on Telfa gauze creates a processed lipoaspirate with a more functional adipokine profile that improves fat graft survival. METHODS: Suction-assisted lipoaspirate was harvested from humans and was either processed by centrifugation, rolled on Telfa gauze, or left unprocessed. Progenitor cell populations were quantified and characterized by flow cytometry. Glycerol-3-phosphate dehydrogenase assay was used to measure the functional adipocytes. The lipoaspirates were grafted into (n = 45) wild-type mice and harvested to assess fat graft persistence. Vascular endothelial growth factor and platelet-derived growth factor-BB secretions were measured by enzyme-linked immunosorbent assay technique. RESULTS: Centrifuged lipoaspirate had a greater number of progenitor cells per gram of tissue than Telfa-processed and unprocessed lipoaspirate. However, Telfa-processed lipoaspirate had a greater number of functional adipocytes (0.104 U/ml) than centrifuged (0.080 U/ml) and unprocessed lipoaspirate (0.083 U/ml) on glycerol-3-phosphate dehydrogenase assay (p < 0.05). After 10 weeks of grafting, it had greater fat graft persistence (70.9 ± 6.2 percent) than centrifuged (56.7 ± 5.5 percent) and unprocessed lipoaspirate (42.2 ± 2.7 percent) (p < 0.05). It also maintained a greater secretion of vascular endothelial growth factor and platelet-derived growth factor-BB at weeks 1 and 2 than centrifuged and unprocessed lipoaspirate. Furthermore, CD31 staining demonstrated an increase in vascular density of the Telfa-processed lipoaspirate at week 2 compared with the centrifuged lipoaspirate (37 ± 1 percent and 14 ± 4 percent per high-power field; p < 0.05). CONCLUSIONS: Lipoaspirate processing technique has a significant impact on fat graft survival rate. Increasing the number of functional adipocytes by processing the fat on Telfa gauze may augment the secretion of angiogenic and mitogenic adipokines within the graft, thereby improving its survivability. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

A Historical Review of Gender-Affirming Medicine: Focus on Genital Reconstruction Surgery.

Gender dysphoria (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) is characterized by a marked discrepancy between one's birth-assigned sex and one's gender identity and is sometimes addressed by gender-affirming surgery. As public visibility and institutional support for the transgender and gender non-conforming population continue to increase, the demand for competent multidisciplinary teams of medical professionals equipped to care for this population is expected to rise-including plastic surgeons, urologists, gynecologists, endocrinologists, and breast surgeons, among others. Genital reconstruction procedures for the male-to-female and female-to-male transgender patient present unique surgical challenges that continue to evolve from their respective origins in the 19th and 20th centuries. A historical review of surgical techniques and standards of care attendant to gender-affirming medicine is presented, with foremost emphasis placed on how techniques for genital reconstruction in particular continue to evolve and advance. In addition, the current status of transition-related health care in the United States, including research gaps and contemporary clinical challenges, is reviewed. Frey JD, Poudrier G, Thomson JE, Hazen A. A Historical Review of Gender-Affirming Medicine: Focus on Genital Reconstruction Surgery. J Sex Med 2017;14:991-1002.

Glycomics, extracellular matrix, and anti-glycan antibodies in exfoliation syndrome.

Exfoliation syndrome (XFS) is considered to be a disease of extracellular matrix. Here we review key experimental evidence of aberrations in structure, expression, and function of glycoproteins, complex carbohydrates, and glycosaminoglycans found in extracellular matrix components forming exfoliation material in patients presenting with XFS. We hypothesize that certain components of the accumulating exfoliation material can become immunogenic, and multiple natural antibodies or autoantibodies are generated. Anti-glycan antibodies (AGAs) can be captured on Printed Glycan Array. Our preliminary results show robust immunoprofiles of AGAs in sera of patients with XFS, and the significant presence of AGAs in aqueous humor of these patients. These findings offer insight into the dynamics of AGAs during the development of XFS that could lead to the identification of the AGA-based XFS immuno-signature.

Organic base effects in NHC promoted O- to C-carboxyl transfer; chemoselectivity profiles, mechanistic studies and domino catalysis.

The O- to C-carboxyl transfer of oxazolyl carbonates promoted by triazolinylidenes, generated in situ with NEt(3), shows a markedly different rate and chemoselectivity profile to the same reaction promoted by triazolinylidenes generated using KHMDS. The mechanism of these pathways has been probed through extensive crossover studies to understand this process. The use of NEt(3) as a base allows domino multi-step reaction sequences to be developed, although chiral NHCs only generate modest levels of asymmetric induction (<15% ee) in these domino reaction processes.

Amidine catalysed O- to C-carboxyl transfer of heterocyclic carbonate derivatives.

The structural requirements of amidines necessary to act as efficient O- to C-carboxyl transfer agents are delineated and the scope of this process outlined through its application to a range of oxazolyl, benzofuranyl and indolyl carbonates.

Tandem multi-step synthesis of C-carboxyazlactones promoted by N-heterocyclic carbenes.

Cascade reaction sequences incorporating N-heterocyclic carbene-based organocatalysis have been developed that allow the direct preparation of a range of (+/-)-4-phenoxycarbonylazlactones in good isolated yields (66-84%) from the corresponding N-p-anisoyl amino acids.