Graphical evidence: forensic animations and virtual reconstructions

Courtroom environments, which have been one of the last bastions of the oral tradition, are slowly morphing into cinematic display environments1 Heintz, M E. 2002. The digital divide and courtroom technology: can David Keep up with goliath?. Federal Communications Law J, 54: 567–589.  [Google Scholar]. The persuasive oral rhetoric of lawyers is increasingly being replaced by compelling visual media displays presenting a range of digital evidence in a convincing and credible manner2 Lederer, F I. 2004. Courtroom technology: for trial lawyers, the future is now. Criminal Justice, 19(1): 14–21.  [Google Scholar]. The digital age has brought a plethora of novel evidence forms, evidence detection methods, and new means of evidence presentation. In particular, three-dimensional reconstructions of evidence offer great potential in the field of forensic science, they can potentially help in the presentation of complex scientific, spatial and temporal data to a non-technical audience3 Schofield, D. . Animating and interacting with graphical evidence: bringing courtrooms to life with virtual reconstructions. Proceedings of IEEE Conference on Computer Graphics, Imaging and Visualisation. Aug14–16, Bangkok, Thailand. pp.321–328.  [Google Scholar]. This paper outlines the forensic process in terms of the tasks and phases involved, specifically relating to the presentation of evidence represented in a digital media form. A range of examples of where evidence has been presented in courtrooms using digital media (particularly forensic animation and virtual reconstruction technology) are described. a ^aThe author acted as an expert witness in all the cases discussed, was responsible for the preparation of the virtual reconstructions described in this paper. Most of the work was undertaken through the author's company in the UK, Aims Solutions Ltd4 Aims Solutions Ltd. Aims Solutions: Innovative Training Software [Internet] Nottingham, , UK Company Web Site; c2006 [cited 2008 April 21]. Available from http://www.aims-sloutions.co.uk [Google Scholar]. There are a number of fundamental implications inherent in the shift from oral to visual mediation, and a number of facets of this modern evidence presentation technology need to be investigated and analysed.     

Vertically unstable pelvic fractures fixed with percutaneous iliosacral screws: does posterior injury pattern predict fixation failure?

OBJECTIVE: To measure the failure rate of percutaneous iliosacral screw fixation of vertically unstable pelvic fractures and particularly to test the hypothesis that fixations in which the posterior injury is a vertical fracture of the sacrum are more likely to fail than fixations with dislocations or fracture-dislocations of the sacroiliac joint. DESIGN: Retrospective review. SETTING: Level 1 trauma center. METHODS: All patients with pelvic fractures admitted between January 1, 1993, and December 31, 1998, were identified from the trauma registry. Hospital records were used to identify patients treated with iliosacral screws. Radiologic studies were examined to identify patients who had unequivocally vertically unstable pelvic fractures. Immediate postoperative and follow-up anteroposterior, inlet, and outlet radiographs from a minimum of 12 months postinjury were examined. Position, length, and numbers of iliosacral screws and any evidence of screw failure (eg, bending or breakage) were recorded. Residual postoperative displacement and late displacement of the posterior pelvis were measured. The main outcome measure was failure, defined as at least 1cm of combined vertical displacement of the posterior pelvis compared with immediate postoperative position. The main analysis was for association between fracture pattern and failure. Patient demographic data, iliosacral screw position, and anterior pelvic fixation method also were studied. RESULTS: The study group comprised 62 patients with unequivocally vertically unstable pelvic fractures in whom the posterior injury was treated with closed reduction and percutaneous iliosacral screw fixation. Of patients, 32 had dislocations or fracture-dislocations of the sacroiliac joint, and 30 had vertical fractures of the sacrum. Fixation failed in four patients, all with vertical sacral fractures and all within the first 3 weeks after surgery. These four patients required revision fixation. In two further cases with vertical sacral fractures, there was evidence that the fracture had only barely been held by the fixation, but these fractures healed, and follow-up radiographs did not meet the displacement criteria for failure. A vertical sacral fracture pattern was associated significantly with failure (Fisher exact test, P = 0.04); the excess risk of failure compared with sacroiliac joint injury was 13% (95% confidence interval 1% to 25%). There was no significant association between failure and anterior fixation method, iliosacral screw arrangement or length, or any demographic or injury variable. CONCLUSIONS: Percutaneous iliosacral screw fixation is a useful technique in the management of vertically unstable pelvic fractures, but a vertical sacral fracture should make the surgeon more wary of fixation failure and loss of reduction.     

Real-time measurement of blood vessel occlusion during microsurgery.

Measurement and feedback of vascular properties during microsurgery is generally not available. We carried out real-time in vivo measurement and analysis of microsurgical occlusion of 1-2-mm diameter arteries and veins in rodents. A pair of forceps mounted with strain gauges was designed for applying and directly measuring the force on tissue. Forces between 0 and 450 mN were applied, with the device having a resolution of 0.5 mN. We performed in vivo experiments on the rat femoral (n = 5) and abdominal (n = 8) blood vessels to measure the elastic restoration force of the tissue in response to radial compression at different levels of force. On average, the minimum occlusion force was 57 mN for the rat artery. During steady application of force, the perturbations in the blood vessel due to heartbeat are visible in the force data. These force oscillations ranged between 1 and 3 mN around the mean steady-state force applied. It was determined that the magnitude of the Fourier spectral peak corresponding to heartbeat frequency can be used as a measure of the patency of the blood vessel, and can provide feedback to microsurgeons to avoid damage to the vessel by application of excess force.     

A comparison of the effects of droperidol and the combination of droperidol and ondansetron on postoperative nausea and vomiting for patients undergoing laparoscopic cholecystectomy

STUDY OBJECTIVES: To compare the prophylactic antiemetic efficacy of the combination of ondansetron and droperidol with that of droperidol alone in patients undergoing elective laparoscopic cholecystectomy. DESIGN: Randomized, double-blind controlled trial.University affiliated teaching hospital after induction of standardized general anesthesia. PATIENTS: 64 ASA physical status I or II patients aged 18 to 80 years, undergoing elective laparoscopic cholecystectomy. INTERVENTION: Following induction of general anesthesia, patients received either droperidol 1.25 mg intravenously (IV; n = 30; Group D) or the combination of droperidol 1.25 mg IV and ondansetron 4 mg IV (n = 34; Group D+O). MEASUREMENTS: Number and severity of nausea episodes, number of emetic episodes, total analgesic consumption, and rescue antiemetic administration were assessed at 1, 3, and 24 hours after admission to the recovery room. Data were analyzed using Fisher's Exact test and unpaired Student's t-test; a p-value <0.05 was considered significant. RESULTS: The proportions of patients who experienced nausea (70% and 53% for D and D+O groups, respectively) and vomiting (30% and 19% for D and D+O groups, respectively) were similar in the two groups. The frequency of moderate and severe nausea (requiring administration of antiemetic) was less in group D + O (7%) compared with group D (19%; p < 0.05). CONCLUSIONS: Patients who received the combination of droperidol and ondansetron experienced less severe nausea compared with patients who received droperidol alone.     

The Selective Non-operative Management of Penetrating Cervical Venous Trauma is Safe and Effective

Background

This paper reviews our experience with penetrating cervical venous trauma and aims to validate the selective non-operative management (SNOM) of these injuries.

Methods

This was a retrospective review of a prospectively maintained registry. All patients presenting alive with an injury to the internal jugular vein, subclavian vein or innominate vein following a PNI were reviewed for a 6-year period.

Results

Among 817 patients admitted for the management of PNI, 76 (9.3%) had a venous injury. Of these, 37 (48.7%) patients were managed non-surgically, 20 (26.3%) required immediate surgical exploration, seven of whom had an associated arterial injury, and 19 (25%) underwent surgery following a diagnostic CTA, 16 of whom had an associated arterial or aero-digestive injury. In total, only 16 (21.1%) of the 76 patients required exploration for venous injury alone. The majority (63.2%) of patients had a history of severe bleeding or hemodynamic instability prior to arrival, but only 20 (26.3%) required immediate exploration. Two (2.6%) patients died as a result of venous injury. No patients developed complications related to the venous injury.

Conclusions

SNOM is applicable to a well-defined subset of patients with isolated penetrating cervical venous trauma to the IJV and SCV identified on CTA.

     

Isolated main pancreatic duct injuries spectrum and management

BACKGROUND: We present our experience with the rare injury of isolated major pancreatic duct disruption. METHODS: From 1997 to 2003, 3 females and 13 males whose age ranged from 4 to 46 years were identified. Stabs caused 2 and blunt trauma 14 injuries. Nine presented acutely. Delay occurred in 7 patients, 6 with pseudocysts and 1 with infected pancreatic necrosis. RESULTS: Nine cases were managed in the acute phase: 6 by splenic-preserving distal pancreatectomy and 2 by distal pancreatico-enteric anastomosis; 1 was drained. A small pseudocyst and transient pancreatic fistula were the only complications. The 6 cases with pseudocysts were managed endoscopically. Five were stented and 1 was drained without stent. Four had resolution. Two had stent cyst migration. One required a pancreaticojejunostomy and another distal pancreatectomy. One patient died of infected pancreatic necrosis. Long-term outcome could not be assessed. CONCLUSION: In the acute situation, resection or distal pancreatico-enteric anastomoses are attainable with low morbidity. Endoscopic pseudocyst management options are feasible, with good short-term resolution. Giant cysts may be better managed operatively.