Characterizing the learning curve of a virtual intracorporeal suturing simulator VBLaST-SS©.

BACKGROUND: The virtual basic laparoscopic skill trainer suturing simulator (VBLaST-SS©) was developed to simulate the intracorporeal suturing task in the FLS program. The purpose of this study was to evaluate the training effectiveness and participants' learning curves on the VBLaST-SS© and to assess whether the skills were retained after 2 weeks without training. METHODS: Fourteen medical students participated in the study. Participants were randomly assigned to two training groups (7 per group): VBLaST-SS© or FLS, based on the modality of training. Participants practiced on their assigned system for one session (30 min or up to ten repetitions) a day, 5 days a week for three consecutive weeks. Their baseline, post-test, and retention (after 2 weeks) performance were also analyzed. Participants' performance scores were calculated based on the original FLS scoring system. The cumulative summation (CUSUM) method was used to evaluate learning. Two-way mixed factorial ANOVA was used to compare the effects of group, time point (baseline, post-test, and retention), and their interaction on performance. RESULTS: Six out of seven participants in each group reached the predefined proficiency level after 7 days of training. Participants' performance improved significantly (p < 0.001) after training within their assigned group. The CUSUM learning curve shows that one participant in each group achieved 5% failure rate by the end of the training period. Twelve out of fourteen participants' CUSUM curves showed a negative trend toward achieving the 5% failure rate after further training. CONCLUSION: The VBLaST-SS© is effective in training laparoscopic suturing skill. Participants' performance of intracorporeal suturing was significantly improved after training on both systems and was retained after 2 weeks of no training.

Correction to: Validation of a virtual intracorporeal suturing simulator.

The surname of Sreekanth Arikatla incorrectly appeared as Sreekanth Artikala.

Validation of a virtual intracorporeal suturing simulator.

BACKGROUND: Intracorporeal suturing is one of the most important and difficult procedures in laparoscopic surgery. Practicing on a FLS trainer box is effective but requires large number of consumables, and the scoring is somewhat subjective and not immediate. A virtualbasic laparoscopic skill trainer (VBLaST©) was developed to simulate the five tasks of the FLS Trainer Box. The purpose of this study is to evaluate the face and content validity of the VBLaST suturing simulator (VBLaST-SS©). METHODS: Twenty-five medical students and residents completed an evaluation of the simulator. The participants were asked to perform the standard intracorporeal suturing task on both VBLaST-SS© and the traditional FLS box trainer. The performance scores on each system were calculated based on time (s), deviations to the black dots (mm), and incision gap (mm). The participants were then asked to finish a 13-item questionnaire with ratings from 1 (not realistic/useful) to 5 (very realistic/useful) regarding the face validity of the simulator. A Wilcoxon signed rank test was performed to identify differences in performance on the VBLaST-SS© compared to that of the traditional FLS box trainer. RESULTS: Three questions from the face validity questionnaire were excluded due to lack of response. Ratings to 8 of the remaining 10 questions (80%) averaged above 3.0 out of 5. Average intracorporeal suturing completion time on the VBLaST-SS© was 421 (SD = 168 s) seconds compared to 406 (175 s) seconds on the box trainer (p = 0.620). There was a significant difference between systems for the incision gap (p = 0.048). Deviation in needle insertion from the black dot was smaller for the box trainer than the virtual simulator (1.68 vs. 7.12, p < 0.001). CONCLUSION: Participants showed comparable performance on the VBLaST-SS© and traditional box trainer. Overall, the VBLaST-SS© system showed face validity and has the potential to support training for the suturing skills.

Toxicity of Nickel on the Selected Species of Marine Diatoms and Copepods.

Toxicity values for nickel on marine diatoms and copepods were derived based on bioassay tests. The 96 h IC50 of nickel on diatoms, Odontella mobiliensis and Coscinodiscus centralis were 0.31 ± 0.01 and 0.62 ± 0.02 mg/L and LC50 values on copepods, Oithona similis and Acartia danae were 2.78 ± 0.14 and 2.34 ± 0.32 mg/L, respectively. The species mean chronic values of nickel were 0.016, 0.17, 0.57 and 0.42 mg/L for O. mobiliensis, C. centralis, O. similis and A. danae, respectively. A hazardous concentration was derived and evaluated using the species sensitivity distribution (SSD) method. SSD indicated that 13 µg Ni/L is the maximum allowable concentration for protection of 95% plankton species in coastal and marine ecosystem of India. Diatoms are more sensitive to nickel than copepods by almost an order of magnitude. The toxicity values derived in the present study may be useful to calculate ambient water quality criteria/standard for nickel.

Virtual interactive suturing for the Fundamentals of Laparoscopic Surgery (FLS).

BACKGROUND: Suturing with intracorporeal knot-tying is one of the five tasks of the Fundamentals of Laparoscopic Surgery (FLS), which is a pre-requisite for board certification in general surgery. This task involves placing a short suture through two marks in a penrose drain and then tying a double-throw knot followed by two single-throw knots using two needle graspers operated by both hands. A virtual basic laparoscopic skill trainer (VBLaST©) is being developed to represent the virtual versions of the FLS tasks, including automated, real time performance measurement and feedback. In this paper, we present the development of a VBLaST suturing simulator (VBLaST-SS©). Developing such a simulator involves solving multiple challenges associated with fast collision detection, response and force feedback. METHODS: In this paper, we present a novel projection-intersection based knot detection method, which can identify the validity of different types of knots at haptic update rates. A simple and robust edge-edge based collision detection algorithm is introduced to support interactive knot tying and needle insertion operations. A bimanual hardware interface integrates actual surgical instruments with haptic devices enabling not only interactive rendering of force feedback but also realistic sensation of needle grasping, which realizes an immersive surgical suturing environment. RESULTS: Experiments on performing the FLS intracorporeal suturing task show that the simulator is able to run on a standard personal computer at interactive rates. CONCLUSIONS: VBLaST-SS© is a computer-based interactive virtual simulation system for FLS intracorporeal knot-tying suturing task that can provide real-time objective assessment for the user's performance.

An Interesting and Rare Case of Hemoglobin D-Punjab Variant in Tamil Nadu.

Hemoglobin D (Hb D), a variant of hemoglobin appears in a few Asian individuals belonging to India, Pakistan, Iran, Iraq, and other parts of the world. In India, it is mainly reported in the North-Western states. Hb D disease causes subclinical jaundice, or it may be asymptomatic with pallor in its heterozygous form. Being a country with hunger and poverty, pallor is always attributed to iron deficiency anemia, but one should not miss out on various other causes. Here, we report a rare case of Hb D with iron deficiency anemia in a 13-year-old child of South Indian origin (Tamil Nadu) and emphasize the detailed evaluation of cases with severe pallor. He presented with gradually progressing generalized weakness with easy fatigability for the past four weeks. On examination, he was pale, there was no icterus and systemic examination was normal. Investigation revealed a microcytic hypochromic type of anemia. Hb electrophoresis showed the Hb D-Punjab variant. Iron indices were suggestive of iron deficiency anemia. He was advised iron supplements for three months, and he improved with that. He was counseled about his disease and was advised regular follow-up.

Effect of Light-Emitting Diode Phototherapy on Serum Calcium Levels in Neonates With Jaundice.

BACKGROUND: To assess the change in serum total calcium levels during light-emitting diode phototherapy treatment for jaundice in term neonates. METHODS: A prospective observational study was done on 104 term neonates with hyperbilirubinemia in a tertiary care center to investigate the effects of phototherapy using a light-emitting diode device. The total serum bilirubin along with total calcium levels was measured at the start and at the end of phototherapy. Additionally, all the newborns enrolled in the study were evaluated for hypocalcaemia-related symptoms such as jitteriness, irritability/excitability, lethargy, and convulsions. RESULTS: A significant lowering of posttreatment total calcium level compared to that of pretreatment level (p<0.001) was found in our study. Hypocalcemia (serum calcium <8 mg/dL in term neonates) was found in 12.5% of the study subjects. CONCLUSIONS: In the treatment of neonatal jaundice, similar to conventional blue and white light phototherapy, light-emitting diode phototherapy also has hypocalcemia as an adverse effect. We recommend monitoring these babies for hypocalcemia during light-emitting diode phototherapy.

A constrained spline dynamics (CSD) method for interactive simulation of elastic rods.

In this paper, we present constrained spline dynamics (CSD) as a unified framework for the elastodynamic simulation of elastic rods subjected to constraints at interactive rates. The geometry of the rod and its kinematics are discretized using smooth spline functions and the rod's centerline co-ordinates as degrees of freedom (DOF). Interpolating B-spline shape functions are used to take advantage of the smooth basis and the Kronecker delta property. The formulation is developed from Hamilton's principle with bending and twisting energies represented as compliant constraints. The bend-twist coupled behavior is modeled using the concept of holonomy of curves utilizing the smooth and accurate curvature and bi-normal vector fields, eliminating rotational director frames as degrees of freedom. By enforcing uniform arc-length parametrization, high accuracy is achieved in modeling bend, twist, and bend-twist coupling. Several numerical examples are presented that demonstrate the convergence behavior, computational accuracy and efficiency of the formulation.