Needs analysis for developing a virtual-reality NOTES simulator

Introduction and study aim

Natural orifice translumenal endoscopic surgery (NOTES) is an emerging surgical technique that requires a cautious adoption approach to ensure patient safety. High-fidelity virtual-reality-based simulators allow development of new surgical procedures and tools and train medical personnel without risk to human patients. As part of a project funded by the National Institutes of Health, we are developing the virtual transluminal endoscopic surgery trainer (VTEST?) for this purpose. The objective of this study is to conduct a structured needs analysis to identify the design parameters for such a virtual-reality-based simulator for NOTES.

Methods

A 30-point questionnaire was distributed at the 2011 National Orifice Surgery Consortium for Assessment and Research meeting to obtain responses from experts. Ordinal logistic regression and the Wilcoxon rank-sum test were used for analysis.

Results

A total of 22 NOTES experts participated in the study. Cholecystectomy (CE, 68 %) followed by appendectomy (AE, 63 %) (CE vs AE, p = 0.0521) was selected as the first choice for simulation. Flexible (FL, 47 %) and hybrid (HY, 47 %) approaches were equally favorable compared with rigid (RI, 6 %) with p < 0.001 for both FL versus RI and HY versus RI. The transvaginal approach was preferred 3 to 1 to the transgastric. Most participants preferred two-channel (2C) scopes (65 %) compared with single (1C) or three (3C) or more channels with p < 0.001 for both 2C versus 1C and 2C versus 3C. The importance of force feedback and the utility of a virtual NOTES simulator in training and testing new tools for NOTES were rated very high by the participants.

Conclusion

Our study reinforces the importance of developing a virtual NOTES simulator and clearly presents expert preferences. The results of this analysis will direct our initial development of the VTEST? platform.     

Prospective Evaluation of a Molecular Marker Panel for Prediction of Recurrence and Cancer-specific Survival After Radical Cystectomy

Background

Retrospective studies demonstrated that cell cycle–related and proliferation biomarkers add information to standard pathologic tumor features after radical cystectomy (RC). There are no prospective studies validating the clinical utility of markers in bladder cancer.

Objective

To prospectively determine whether a panel of biomarkers could identify patients with urothelial carcinoma of the bladder (UCB) who were likely to experience disease recurrence or mortality.

Design, setting, and participants

Between January 2007 and January 2012, every patient with high-grade bladder cancer, including 216 patients treated with RC and lymphadenectomy, underwent immunohistochemical staining for tumor protein p53 (Tp53); cyclin-dependent kinase inhibitor 1A (p21, Cip1) (CDKN1A); cyclin-dependent kinase inhibitor 1B (p27, Kip1); antigen identified by monoclonal antibody Ki-67 (MKI67); and cyclin E1.

Intervention

Every patient underwent RC and lymphadenectomy, and marker staining.

Outcome measurements and statistical analysis

Cox regression analyses tested the ability of the number of altered biomarkers to predict recurrence or cancer-specific mortality (CSM).

Results and limitations

Pathologic stage among the study population was pT0 (5%), pT1 (35%), pT2 (19%), pT3 (29%), and pT4 (13%); lymphovascular invasion (LVI) was seen in 34%. The median number of removed lymph nodes was 23, and 60 patients had lymph node involvement (LNI). Median follow-up was 20 mo. Expression of p53, p21, p27, cyclin E1, and Ki-67 were altered in 54%, 26%, 46%, 15%, and 75% patients, respectively. In univariable analyses, pT stage, LNI, LVI, perioperative chemotherapy (CTx), margin status, and number of altered biomarkers predicted disease recurrence. In a multivariable model adjusting for pathologic stage, margins, LNI, and adjuvant CTx, only LVI and number of altered biomarkers were independent predictors of recurrence and CSM. The concordance index of a baseline model predicting CSM (including pathologic stage, margins, LVI, LNI, and adjuvant CTx) was 80% and improved to 83% with addition of the number of altered markers.

Conclusions

Molecular markers improve the prediction of recurrence and CSM after RC. They may identify patients who might benefit from additional treatments and closer surveillance after cystectomy.     

Common uses and cited complications of energy in surgery

Background

Instruments that apply energy to cut, coagulate, and dissect tissue with minimal bleeding facilitate surgery. The improper use of energy devices may increase patient morbidity and mortality. The current article reviews various energy sources in terms of their common uses and safe practices.

Methods

For the purpose of this review, a general search was conducted through NCBI, SpringerLink, and Google. Articles describing laparoscopic or minimally invasive surgeries using single or multiple energy sources are considered, as are articles comparing various commercial energy devices in laboratory settings. Keywords, such as laparoscopy, energy, laser, electrosurgery, monopolar, bipolar, harmonic, ultrasonic, cryosurgery, argon beam, laser, complications, and death were used in the search.

Results

A review of the literature shows that the performance of the energy devices depends upon the type of procedure. There is no consensus as to which device is optimal for a given procedure. The technical skill level of the surgeon and the knowledge about the devices are both important factors in deciding safe outcomes.

Conclusions

As new energy devices enter the market increases, surgeons should be aware of their indicated use in laparoscopic, endoscopic, and open surgery.     

Characterizing the learning curve of the VBLaST-PT© (Virtual Basic Laparoscopic Skill Trainer)

Background

Mastering laparoscopic surgical skills requires considerable time and effort. The Virtual Basic Laparoscopic Skill Trainer (VBLaST-PT^©) is being developed as a computerized version of the peg transfer task of the Fundamentals of Laparoscopic Surgery (FLS) system using virtual reality technology. We assessed the learning curve of trainees on the VBLaST-PT^© using the cumulative summation (CUSUM) method and compared them with those on the FLS to establish convergent validity for the VBLaST-PT^©.

Methods

Eighteen medical students from were assigned randomly to one of three groups: control, VBLaST-training, and FLS-training. The VBLaST and the FLS groups performed a total of 150 trials of the peg-transfer task over a 3-week period, 5 days a week. Their CUSUM scores were computed based on predefined performance criteria (junior, intermediate, and senior levels).

Results

Of the six subjects in the VBLaST-training group, five achieved at least the “junior” level, three achieved the “intermediate” level, and one achieved the “senior” level of performance criterion by the end of the 150 trials. In comparison, for the FLS group, three students achieved the “senior” criterion and all six students achieved the “intermediate” and “junior” criteria by the 150th trials. Both the VBLaST-PT^© and the FLS systems showed significant skill improvement and retention, albeit with system specificity as measured by transfer of learning in the retention test: The VBLaST-trained group performed better on the VBLaST-PT^© than on FLS (p = 0.003), whereas the FLS-trained group performed better on the FLS than on VBLaST-PT^© (p = 0.002).

Conclusions

We characterized the learning curve for a virtual peg transfer task on the VBLaST-PT^© and compared it with the FLS using CUSUM analysis. Subjects in both training groups showed significant improvement in skill performance, but the transfer of training between systems was not significant.     

A rare presentation of hepatic and splenic cystic malignant fibrous histiocytoma: A case report and literature review

INTRODUCTIONMalignant fibrous histiocytoma is one of the most common soft tissue sarcomas in late adult life. But primary visceral malignant fibrous histiocytoma is a very rare entity. In peripheries, it is known to have an aggressive behavior but its biological pattern when involving liver and spleen is not well understood due to the rarity of its occurrence.PRESENTATION OF CASEA case of malignant fibrous histiocytoma of the liver and spleen as multiple cystic lesions in a 30 years old man is reported. The patient presented with hepatosplenomegaly resulting in central abdominal distention. Pre-operative investigations pointed toward the diagnosis of malignant cystic disease. The tumor presented as multiple hepatic cysts with massive hepatomegaly and splenomegaly. These cysts contained hemorrhagic fluid. Biopsy revealed highly cellular pleomorphic spindle cells fascicles arranged in storiform pattern at places with frequent mitoses. Immunohistochemistry revealed viamentin positivity. The tumor is compared with previous case reports.DISCUSSIONMalignant fibrous histiocytoma of liver and spleen has been mentioned in the literature as isolated case reports and most of these present as solid lesions but presentation as multiple cysts is also a possibility as was seen in this patient. It can be confirmed only on histo-pathology supported by immunohistochemistry. The disease carries guarded prognosis due to its rapid progression and diagnostic dilemma pre-operatively.CONCLUSIONThis rare malignancy affecting the viscera can be diagnosed only with high index of suspicion and awareness regarding its presentation can help surgeons deal with it.     

Revascularization with and without Platelet-rich Plasma in Nonvital,Immature, Anterior Teeth: A Pilot Clinical Study

Introduction

This study was conducted to evaluate and compare maturogenesis induced by revascularization with and without platelet-rich plasma (PRP).

Methods

Twenty patients with nonvital, immature anterior teeth were randomly categorized into 2 groups. Subsequent to chemomechanical preparation, revascularization with and without PRP carried on a collagen sponge was induced in groups 1 and 2, respectively. The cases were followed up clinically and radiographically at 6- and 12-month intervals.

Results

Clinically, all cases were asymptomatic with complete resolution of signs and symptoms. Radiographically, there was a marked difference in periapical healing, apical closure, and dentinal wall thickening in group 2 in comparison with group 1. However, root lengthening was comparable for both of the procedures.

Conclusions

Revascularization is a conservative and an effective method for inducing maturogenesis in nonvital, immature teeth. Supplementations with PRP can potentially improve the desired biological outcome of this regenerative technique.     

Digital assessment and quantification of pelvic organ prolapse (DPOP-Q): a randomised cross-over diagnostic agreement trial

Introduction

Pelvic Organ Prolapse Quantification (POP-Q) system, measured in centimetres using a ruler (e.g. POPstix®), is recommended to quantify prolapse severity. POPstix® are costly (US $1/ruler). Home-made devices are used instead, but these have not been shown to be reproducible.

Hypothesis

Digitally assessed POP-Q (DPOP-Q) is as reliable, reproducible and acceptable as POP-Q assessed using POPstix®.

Methods

In this randomised crossover diagnostic agreement trial, each assessor measured the index finger of their dominant hand using a ruler. At visit one, patients were randomised to either POPstix® POP-Q assessment in a modified lithotomy position or DPOP-Q in both modified a lithotomy and a standing position. After the first clinician conducted this assessment, a second blinded clinician then carried out the remaining assessment on the same patient. For each examination, duration was recorded, along with a patient-completed discomfort score. Twenty-five women were invited for visit two, at which DPOP-Q was recorded by the same clinician who undertook DPOP-Q at the first visit. This allowed evaluation of inter- and intraobserver agreement together with examination acceptability.

Results

One hundred and nine women were recruited [median age 55 years, parity 2, body mass index (BMI) 27.1]. Of the 25 patients invited, 23 returned for visit two. DPOP-Q had high interobserver reliability [κ?=?0.94, 95 % confidence interval (CI) 0.878–0.996] and intraobserver reliability (α?=?0.96) with POPstix®. DPOP-Q was significantly quicker (p?=?0.02) and less uncomfortable (p?<?0.01) than POPstix® POP-Q.

Conclusion

DPOP-Q is reliable, acceptable and cost effective.

     

Recent advances in targeting the autotaxin-lysophosphatidate-lipid phosphate phosphatase axis in vivo

Extracellular lysophosphatidate(LPA) is a potent bioactive lipid that signals through six G-protein-coupled receptors.This signaling is required for embryogenesis,tissue repair and remodeling processes.LPA is produced from circulating lysophosphatidylcholine by autotaxin(ATX),and is degraded outside cells by a family of three enzymes called the lipid phosphate phosphatases(LPPs).In many pathological conditions,particularly in cancers,LPA concentrations are increased due to high ATX expression and low LPP activity.In cancers,LPA signaling drives tumor growth,angiogenesis,metastasis,resistance to chemotherapy and decreased efficacy of radiotherapy.Hence,targeting the ATX-LPA-LPP axis is an attractive strategy for introducing novel adjuvant therapeutic options.In this review,we will summarize current progress in targeting the ATX-LPA-LPP axis with inhibitors of autotaxin activity,LPA receptor antagonists,LPA monoclonal antibodies,and increasing low LPP expression.Some of these agents are already in clinical trials and have applications beyond cancer,including chronic inflammatory diseases.