Starting late does not increase the risk of post-operative complications in patients undergoing common general surgical procedures.

BACKGROUND: There is a paucity of evidence surrounding the issue of delays on the day of surgery with respect to both causes and consequences. We sought to determine whether patients whose operations started late were at increased risk of post-operative complications. METHODS: We conducted a retrospective cohort study of 1420 first-of-the-day common general surgical procedures, dividing these into "on-time start" (OTS) and "late-start" (LS) cases. Our primary outcomes were minor and major complication rate; our secondary objective was to identify factors predicting LS. Groups were compared using univariable and multivariable analysis. RESULTS: LS rate was 55.3%. On univariable analysis, LS had higher rates of major and minor complications (7.3% vs. 3.5%, p = 0.002; 3.8% vs. 1.6%, p = 0.011). On multivariable analysis, LS was not associated with increased odds of any complications. Minor complications were predicted by operative duration [OR = 1.005 (1.002-1.008)], female sex [OR = 1.78 (1.037-3.061)], and undergoing an ileostomy closure procedure [OR = 10.60 (2.791-40.246)], and were reduced in those undergoing surgery on Wednesdays [OR = 0.38 (0.166-0.876)]. Major complications were predicted by operative duration [OR = 1.007 (1.003-1.011)] and ASA class [OR = 6.73 (1.505-30.109)]. Multivariable analysis using LS as an outcome identified that anesthesia time [OR = 1.35 (1.031-1.403)], insulin-dependent diabetes [OR = 1.91 (1.128-3.246)], and dyspnea upon moderate exertion [OR = 2.52 (1.423-4.522)] were predictive of LS. CONCLUSIONS: Most cases in our study started late. While this has significant efficiency and economic costs, it is not associated with adverse patient outcomes. This topic remains incompletely described. Further research is needed to improve efficiency and patient experience by investigating the causes of operative delays.

The effect of operative duration on the outcome of colon cancer procedures.

BACKGROUND: Prolonged operative duration has been associated with increased post-operative morbidity in numerous surgical subspecialties; however, data are limited in operations for colon cancer specifically and existing literature makes unwarranted methodological assumptions of linearity. We sought to assess the effects of extended operative duration on perioperative outcomes in those undergoing segmental colectomy for cancer using a methodologically sound approach. METHODS: We conducted a retrospective cohort study of patients undergoing segmental colectomy for cancer between 2014 and 2018, logged in the National Surgical Quality Improvement Program datasets. Our primary outcome was a composite of any complication within 30 days; secondary outcomes included length of stay and discharge disposition. Our main factor of interest was operative duration. RESULTS: We analyzed 26,380 segmental colectomy cases, the majority of which were approached laparoscopically (64.95%) and were right sided (62.93%). Median operative duration was 152 (95% CI 112-206) minutes. On multivariable regression, increased operative duration was linearly associated with any complication (OR = 1.003, 95% CI 1.003-1.003, p < 0.0001) in the overall cohort, as was length of stay (p < 0.0001). All subgroups except for the laparoscopic left colectomy group were linearly associated with operative duration. In the laparoscopic left colectomy group, an inflection point in the odds of any complication was found at 176 min (OR = 1.39, 95% CI 1.20-1.61, p < 0.0001). CONCLUSIONS: This study suggests that the risk of perioperative complications increases linearly with increasing operative duration, where each additional 30 min increases the odds of complication by 10%. In those undergoing laparoscopic left colectomy, the risk of complications sharply increases after ~ 3 h, suggesting that surgeons should aim to complete these procedures within 3 h where possible.

Neoadjuvant therapy versus direct to surgery for T4 colon cancer: meta-analysis.

BACKGROUND: Despite persistently poor oncological outcomes, approaches to the management of T4 colonic cancer remain variable, with the role of neoadjuvant therapy unclear. The aim of this review was to compare oncological outcomes between direct-to-surgery and neoadjuvant therapy approaches to T4 colon cancer. METHODS: A librarian-led systematic search of MEDLINE, Embase, the Cochrane Library, Web of Science, and CINAHL up to 11 February 2020 was performed. Inclusion criteria were primary research articles comparing oncological outcomes between neoadjuvant therapies or direct to surgery for primary T4 colonic cancer. Based on PRISMA guidelines, screening and data abstraction were undertaken in duplicate. Quality assessment was carried out using Cochrane risk-of-bias tools. Random-effects models were used to pool effect estimates. This study compared pathological resection margins, postoperative morbidity, and oncological outcomes of cancer recurrence and overall survival. RESULTS: Four studies with a total of 43 063 patients met the inclusion criteria. Compared with direct to surgery, neoadjuvant therapy was associated with increased rates of margin-negative resection (odds ratio (OR) 2.60, 95 per cent c.i. 1.12 to 6.02; n = 15 487) and 5-year overall survival (pooled hazard ratio 1.42, 1.10 to 1.82, I2 = 0 per cent; n = 15 338). No difference was observed in rates of cancer recurrence (OR 0.42, 0.15 to 1.22; n = 131), 30-day minor (OR 1.12, 0.68 to 1.84; n = 15 488) or major (OR 0.62, 0.27 to 1.44; n = 15 488) morbidity, or rates of treatment-related adverse effects. CONCLUSION: Compared with direct to surgery, neoadjuvant therapy improves margin-negative resection rates and overall survival.

Interventions and Outcomes for Neoadjuvant Treatment of T4 Colon Cancer: A Scoping Review.

While adjuvant treatment of colon cancers that penetrate the serosa (T4) have been well-established, neoadjuvant strategies have yet to be formally evaluated. Our objective was to perform a scoping review of eligibility criteria, treatment regimens, and primary outcomes for neoadjuvant approaches to T4 colon cancer. A librarian-led, systematic search of MEDLINE, Embase, Cochrane Library, Web of Science, and CINAHL up to 11 February 2020 was performed. Primary research evaluating neoadjuvant treatment in T4 colon cancer were included. Screening and data abstraction were performed in duplicate; analyses were descriptive or thematic. A total of twenty studies were included, most of which were single-arm, single-center, and retrospective. The primary objectives of the literature to date has been to evaluate treatment feasibility, tumor response, disease-free survival, and overall survival in healthy patients. Conventional XELOX and FOLFOX chemotherapy were the most commonly administered interventions. Rationale for selecting a specific regimen and for treatment eligibility criteria were poorly documented across studies. The current literature on neoadjuvant strategies for T4 colon cancer is overrepresented by single-center, retrospective studies that evaluate treatment feasibility and efficacy in healthy patients. Future studies should prioritize evaluating clear selection criteria and rationale for specific neoadjuvant strategies. Validation of outcomes in multi-center, randomized trials for XELOX and FOLFOX have the most to contribute to the growing evidence for this poorly managed disease.

Limitations of analytical dose calculations for small field proton radiosurgery.

The purpose of the work was to evaluate the dosimetric uncertainties of an analytical dose calculation engine and the impact on treatment plans using small fields in intracranial proton stereotactic radiosurgery (PSRS) for a gantry based double scattering system. 50 patients were evaluated including 10 patients for each of 5 diagnostic indications of: arteriovenous malformation (AVM), acoustic neuroma (AN), meningioma (MGM), metastasis (METS), and pituitary adenoma (PIT). Treatment plans followed standard prescription and optimization procedures for PSRS. We performed comparisons between delivered dose distributions, determined by Monte Carlo (MC) simulations, and those calculated with the analytical dose calculation algorithm (ADC) used in our current treatment planning system in terms of dose volume histogram parameters and beam range distributions. Results show that the difference in the dose to 95% of the target (D95) is within 6% when applying measured field size output corrections for AN, MGM, and PIT. However, for AVM and METS, the differences can be as great as 10% and 12%, respectively. Normalizing the MC dose to the ADC dose based on the dose of voxels in a central area of the target reduces the difference of the D95 to within 6% for all sites. The generally applied margin to cover uncertainties in range (3.5% of the prescribed range + 1 mm) is not sufficient to cover the range uncertainty for ADC in all cases, especially for patients with high tissue heterogeneity. The root mean square of the R90 difference, the difference in the position of distal falloff to 90% of the prescribed dose, is affected by several factors, especially the patient geometry heterogeneity, modulation and field diameter. In conclusion, implementation of Monte Carlo dose calculation techniques into the clinic can reduce the uncertainty of the target dose for proton stereotactic radiosurgery. If MC is not available for treatment planning, using MC dose distributions to adjust the delivered doses level can also reduce uncertainties below 3% for mean target dose and 6% for the D95.

Marker-based technique for visualizing radiolucent implant components in radiographic imaging.

Radiography is the predominant imaging modality used for the in-vivo analysis of orthopaedic implants. A major disadvantage of radiography is that the articulating joint components that are composed of radiolucent polyethylene cannot be directly visualized. Current strategies attempt to circumvent this limitation by estimating component positions and simplifying the joint system, however, these approaches lead to a number of associated errors. Thus, this study provides a method to enable the visualization of the polyethylene component of total knee replacements in radiographic images. This was achieved through the repeatable insertion of markers and accompanying registration process, which were evaluated in this study for reproducibility and accuracy. An insertion guide was developed to insert tantalum beads into polyethylene tibial surface liners. The bead-inserted liners were micro-CT scanned to obtain 3D surface geometries. An in-vivo mimicking phantom RSA experiment was then used to test the 3D to 2D registration process. The guide positioned the beads consistently to ±0.21 mm. The 3D to 2D registration demonstrated a repeatability of -0.014 ± 0.008 mm. Registration of different bead-inserted tibial liners to the phantom revealed an average error of 0.026 ± 0.047 mm for this visualization method. This visualization approach provides greatly improved registration and inter-component measurements than current alternative strategies. This process is suitable for a number of other joints and would greatly benefit procedures that analyze component interactions and implant performance over time. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2017-2022, 2017.

Radiostereometric analysis using clinical radiographic views: Validation measuring total hip replacement wear.

Radiostereometric analysis (RSA) is a stereo X-ray technique used in clinical research studies to evaluate micro-motion and wear of orthopaedic implants within bone. While highly accurate and precise, its adoption has been limited due to technical requirements such as the need for implanted marker beads and radiograph view angles determined by a calibration cage. We propose a new technique that separates the calibration procedure from the patient examination, enabling clinical radiograph views to be used for RSA measurements. The concept of a reference plate was adapted to establish the link between calibration procedure and patient examination procedure for cassette radiography, which may not be necessary for digital radiography. A hip wear phantom was used to validate this technique by comparing the error and repeatability of the novel procedure with that of conventional RSA. Femoral head penetration was measured versus the acetabular cup (head/cup) and marker beads in the acetabular liner (head/liner). Conventional RSA had lower inferior-superior average error (p = 0.03 for head/cup) while the modified RSA had lower anterior-posterior average error (p = 0.01). Average error was greater but not significantly so for the medial-lateral (p = 0.06) and 3D (p = 0.97) measurements. The head/liner method had lower average errors (p < 0.0001) for both procedures, but did not affect repeatability, which was similar between techniques. The novel procedure's average error and repeatability was therefore, similar to conventional RSA. This new technique could be applied to any joint with two clinical radiograph view angles pending further validation in subjects. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1521-1528, 2016.