Application of discrete cosine transform to assess the effect of tumor motion variations on the definition of ITV in lung and liver SBRT.

PURPOSE: To use Discrete Cosine Transform to include tumor motion variations on ITV definition of SBRT patients. METHODS: Data from 66 patients was collected. 2D planar fluoroscopy images (FI) were available for 54 patients. Daily CBCT projections (CBCTp) from 29 patients were employed to measure interfraction amplitude variability. Systematic amplitude variations were obtained from 17 patients with data from both FI and CBCTp. Tumor motion curves obtained from FI were characterized with a Cosine model (CM), based on cosine functions to the power of 2, 4 or 6, and DCT. Performance of both models was evaluated by means of R2 coefficient and by comparing their results on Internal Target Volume (ITV) margins against those calculated from original tumor motion curves. Amplitude variations from CBCTp, as well as estimations of baseline shift variations were added to the DCT model to account for their effect on ITV margins. RESULTS: DCT replicated tumor motion curves with a mean R2 values for all patients of 0.86, 0.91 and 0.96 for the lateral (LAT), anterior-posterior (AP) and cranio-caudal (CC) directions respectively. CM yielded worst results, with R2 values of 0.64, 0.61 and 0.74 in the three directions. Interfraction amplitude variation increased ITV margins by a 9%, while baseline shift variability implied a 40% and 80-100% increase for normalized values of baseline shift of 0.2 and 0.4 respectively. CONCLUSIONS: Probability distribution functions of tumor positions can be successfully characterized with DCT. This permits to include tumor motion variablilities obtained from patient population into patient specific ITVs.

Predictors of outcome in 101 patients requiring emergent thoracotomy for penetrating pulmonary injuries.

BACKGROUND: Operative interventions are uncommonly required for penetrating pulmonary injuries. Similarly, because their incidence is low, few series appear sporadically in the literature. Objectives of this study are to identify predictors of outcome for patients requiring emergent thoracotomy for penetrating pulmonary injuries and evaluate the use of tissue sparing versus resective techniques for their management. STUDY DESIGN: This is a retrospective 169-month study of all patients with penetrating pulmonary injuries requiring thoracotomy. The main outcome measures are: physiologic parameters, AAST-OIS injury grade, surgical procedures and mortality. Statistical analysis includes univariate and stepwise logistic regression. RESULTS: 101 patients required thoracotomy for penetrating pulmonary injuries. Mechanism of injury includes: gunshot wounds (GSW)-73 (72%), stab wounds (SW)-28 (33%). Mean systolic BP 97 ± 47, mean HR 92 ± 47, and mean admission pH 7.22 ± 0.17. Mean RTS 6.25 ± 2.7, mean ISS 36 ± 22. The mean estimated blood loss (EBL) was 5277 ± 4955 mls. Predictors of outcome are: admission pH (p = 0.0014), admission base deficit (p < 0.0001), packed red blood cells (PRBCs) transfused (p = 0.023), whole blood transfused (p < 0.01). A total of 143 procedures were required in 101 patients: tissue sparing 114 (80%) versus resective procedures 29 (20%). Only pneumonectomy (p = 0.024) predicted outcome. Overall survival 64/101-64%. American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) injury grades I-III versus IV-VI predicts survival (p < 0.001). Stepwise logistic regression identified AAST-OIS injury grades IV-VI (p = 0.007; OR 6.38 [95% CI 1.64-24.78]), intraoperative dysrhythmias (p = 0.003; OR 17.38 [95% CI 2.59-116.49]) and associated cardiac injuries (p = 0.02; OR 8.74 [95% CI 1.37-55.79]) as independent predictors of outcome. CONCLUSIONS: Predictors of outcome for penetrating pulmonary injuries requiring thoracotomy are identified and must be taken into account in their operative management. Tissue sparing techniques-stapled pulmonary tractotomy is once again validated, and it remains effective as the mainstay for their management; however, only pneumonectomy predicts outcome. AAST-OIS injury grades IV-VI predict outcome with higher injury grades requiring resective procedures.

[Laparoscopic cholecystectomy in situs inversus: the disadvantage of being right-handed.]. / Colecistectomía laparoscópica en situs inversus: la desventaja de ser diestro.

OBJECTIVE: To expose our institutional experience on biliary tract surgery in patients with situs inversus. BACKGROUND: Situs inversus is a rare condition of genetic origin, which leads mandatory the modification of surgical technique in laparoscopic cholecystectomy. METHODS: Report of two cases of laparoscopic cholecystectomy in patients with situs in versus. CONCLUSIONS: Laparoscopic cholecystectomy would seem to be the first-line surgical procedure for the treatment of patients with symptomatic gall bladder stones and situs inversus; albeit it imposes special technical demands, it provides the same outcomes of the patients with normal anatomy.