Tumour growth control: analysis of alternative approaches

In this work we address the problem of tumour growth control by properly exploiting a low-dimensional model that grounds on the Chemical Reaction Network (CRN) formalism. Originally conceived to work both in deterministic and stochastic frameworks, it is shown that, except for the case of very low number of tumour cells, the deterministic approach is appropriate to characterize the system behaviour, especially for control planning purposes. Two alternative control approaches are here investigated. One trivially assumes a constant infusion of external drug administration, the other is designed according to a state-feedback control scheme, with complete or partial knowledge of the state. Pros and cons of both control laws are investigated, showing that the tumour size at the beginning of the therapy plays a role of paramount importance for fixed infusion therapies, whilst only state-feedback laws can eradicate arbitrarily large tumours.

ARDS after Pneumonectomy: How to Prevent It? Development of a Nomogram to Predict the Risk of ARDS after Pneumonectomy for Lung Cancer

(1) Background: The cause of ARDS after pneumonectomy is still unclear, and the study of risk factors is a subject of debate. (2) Methods: We reviewed a large panel of pre-, peri- and postoperative data of 211 patients who underwent pneumonectomy during the period 2014−2021. Univariable and multivariable logistic regression was used to quantify the association between preoperative parameters and the risk of developing ARDS, in addition to odds ratios and their respective 95% confidence intervals. A backward stepwise selection approach was used to limit the number of variables in the final multivariable model to significant independent predictors of ARDS. A nomogram was constructed based on the results of the final multivariable model, making it possible to estimate the probability of developing ARDS. Statistical significance was defined by a two-tailed p-value < 0.05. (3) Results: Out of 211 patients (13.3%), 28 developed ARDS. In the univariate analysis, increasing age, Charlson Comorbidity Index and ASA scores, DLCO < 75% predicted, preoperative C-reactive protein (CRP), lung perfusion and duration of surgery were associated with ARDS; a significant increase in ARDS was also observed with decreasing VO2max level. Multivariable analysis confirmed the role of ASA score, DLCO < 75% predicted, preoperative C-reactive protein and lung perfusion. Using the nomogram, we classified patients into four classes with rates of ARDS ranking from 2.0% to 34.0%. (4) Conclusions: Classification in four classes of growing risk allows a correct preoperative stratification of these patients in order to quantify the postoperative risk of ARDS and facilitate their global management.

Characterizing Fractal Genetic Variation in the Human Genome from the Hapmap Project

Over the last decades, the exuberant development of next-generation sequencing has revolutionized gene discovery. These technologies have boosted the mapping of single nucleotide polymorphisms (SNPs) across the human genome, providing a complex universe of heterogeneity characterizing individuals worldwide. Fractal dimension (FD) measures the degree of geometric irregularity, quantifying how "complex" a self-similar natural phenomenon is. We compared two FD algorithms, box-counting dimension (BCD) and Higuchi's fractal dimension (HFD), to characterize genome-wide patterns of SNPs extracted from the HapMap data set, which includes data from 1184 healthy subjects of eleven populations. In addition, we have used cluster and classification analysis to relate the genetic distances within chromosomes based on FD similarities to the geographical distances among the 11 global populations. We found that HFD outperformed BCD at both grand average clusterization analysis by the cophenetic correlation coefficient, in which the closest value to 1 represents the most accurate clustering solution (0.981 for the HFD and 0.956 for the BCD) and classification (79.0% accuracy, 61.7% sensitivity, and 96.4% specificity for the HFD with respect to 69.1% accuracy, 43.2% sensitivity, and 94.9% specificity for the BCD) of the 11 populations present in the HapMap data set. These results support the evidence that HFD is a reliable measure helpful in representing individual variations within all chromosomes and categorizing individuals and global populations.

A comparison among three maximal mathematical models of the glucose-insulin system

The most well-known and widely used mathematical representations of the physiology of a diabetic individual are the Sorensen and Hovorka models as well as the UVAPadova Simulator. While the Hovorka model and the UVAPadova Simulator only describe the glucose metabolism of a subject with type 1 diabetes, the Sorensen model was formulated to simulate the behaviour of both normal and diabetic individuals. The UVAPadova model is the most known model, accepted by the FDA, with a high level of complexity. The Hovorka model is the simplest of the three models, well documented and used primarily for the development of control algorithms. The Sorensen model is the most complete, even though some modifications were required both to the model equations (adding useful compartments for modelling subcutaneous insulin delivery) and to the parameter values. In the present work several simulated experiments, such as IVGTTs and OGTTs, were used as tools to compare the three formulations in order to establish to what extent increasing complexity translates into richer and more correct physiological behaviour. All the equations and parameters used for carrying out the simulations are provided.

A mathematical model of cardiovascular dynamics for the diagnosis and prognosis of hemorrhagic shock

A variety of mathematical models of the cardiovascular system have been suggested over several years in order to describe the time-course of a series of physiological variables (i.e. heart rate, cardiac output, arterial pressure) relevant for the compensation mechanisms to perturbations, such as severe haemorrhage. The current study provides a simple but realistic mathematical description of cardiovascular dynamics that may be useful in the assessment and prognosis of hemorrhagic shock. The present work proposes a first version of a differential-algebraic equations model, the model dynamical ODE model for haemorrhage (dODEg). The model consists of 10 differential and 14 algebraic equations, incorporating 61 model parameters. This model is capable of replicating the changes in heart rate, mean arterial pressure and cardiac output after the onset of bleeding observed in four experimental animal preparations and fits well to the experimental data. By predicting the time-course of the physiological response after haemorrhage, the dODEg model presented here may be of significant value for the quantitative assessment of conventional or novel therapeutic regimens. The model may be applied to the prediction of survivability and to the determination of the urgency of evacuation towards definitive surgical treatment in the operational setting.

Modeling continuous glucose monitoring with fractional differential equations subject to shocks

Continuous Glucose Monitoring (CGM) produces long time-series of noisy observations of a single variable (tissue glucose concentration), whose evolution may be explained by a dynamical model. In order to represent the unknown mixture of possible control mechanisms of different orders affecting the measured variable, a fractional differential approach seems justified. In any case, variations in food intake and/or physical activity ought to be taken into account if a plausible interpretation of the dynamics is to be obtained. In the present work, the mathematical construction and the numerical implementation of a Fractional Differential Equations (FDE) initial value problem are systematically reviewed, with the intent of offering the reader a concise and mathematically rigorous description of this approach. An FDE model for CGM is formulated: the model includes compartments for stomach and intestinal glucose contents and for blood and tissue (subcutaneous) glucose concentrations, as well as the shock effects of food ingestion and of increased glucose consumption due to physical activity. The model parameters, including the (non-integer) order of differentiation, are estimated from CGM observations on six Type 1 diabetic patients. The best-fit fractional orders for the six subjects range from 1.59 to 2.13. For comparison, best fits have also been computed for all subjects using an average fractional order of 1.9 and integer orders of 1 and 2.The results indicate that in the case of CGM the fractional differential model, which should be physiologically more appropriate, in fact fits the data much better than the first-order model and also better than the 2nd-order model.

A quasi-equilibrium reduced model of pancreatic insulin secretion

Much attention has been devoted in the last few decades to mathematical models of insulin secretion, in order to better understand the regulation of glycemia and its derangements. The glucose-insulin homeostatic mechanism is so complex and gives rise to such diverse behavior following perturbations that different models had been published, which reproduced the results of single experiments. More recently, a unifying model of pancreatic insulin secretion was proposed, which is able to account, with a single value of the (meta)parameters, for the wide array of clinically observed behavior. This model explicitly represented the pulsatile nature of the many pancreatic hormone-secreting firing units: the price to pay for its flexibility and performance is the very high dimensionality (hundreds of thousand equations) of the corresponding dynamical system. Clearly, it would be desirable to reduce this model to a much simpler form while retaining its power to reproduce heterogeneous phenomena. The present work reviews the qualitative behavior of this pancreas pulsatile model and offers some insight into its reduction in equilibrium and quasi-equilibrium conditions, also considering single-shot (non-repeated) glucose jumps from an approximately resting condition (such as would occur in standard Intra-Venous bolus dosing of glucose during diabetes diagnostic maneuvers). The resulting quasi-steady-state model can be further endowed with additional lower-order dynamics to also approximate transient behavior. Although a more accurate reduction of the original pulsatile model is left to further investigation, numerical results confirm the biomedical applicability of the formulation already obtained.

Optimal design of lock-down and reopening policies for early-stage epidemics through SIR-D models

The diffusion of COVID-19 represents a real threat for the health and economic system of a country. Therefore the governments have to adopt fast containment measures in order to stop its spread and to prevent the related devastating consequences. In this paper, a technique is proposed to optimally design the lock-down and reopening policies so as to minimize an aggregate cost function accounting for the number of individuals that decease due to the spread of COVID-19. A constraint on the maximal number of concomitant infected patients is also taken into account in order to prevent the collapse of the health system. The optimal procedure is built on the basis of a simple SIR model that describes the outbreak of a generic disease, without attempting to accurately reproduce all the COVID-19 epidemic features. This modeling choice is motivated by the fact that the containing measurements are actuated during the very first period of the outbreak, when the characteristics of the new emergent disease are not known but timely containment actions are required. In fact, as a consequence of dealing with poor preliminary data, the simplest modeling choice is able to reduce unidentifiability problems. Further, the relative simplicity of this model allows to compute explicitly its solutions and to derive closed-form expressions for the maximum number of infected and for the steady-state value of deceased individuals. These expressions can be then used to design static optimization problems so to determine the (open-loop) optimal lock-down and reopening policies for early-stage epidemics accounting for both the health and economic costs.

A revised Sorensen model: Simulating glycemic and insulinemic response to oral and intra-venous glucose load

In 1978, Thomas J. Sorensen defended a thesis in chemical engineering at the University of California, Berkeley, where he proposed an extensive model of glucose-insulin control, model which was thereafter widely employed for virtual patient simulation. The original model, and even more so its subsequent implementations by other Authors, presented however a few imprecisions in reporting the correct model equations and parameter values. The goal of the present work is to revise the original Sorensen's model, to clearly summarize its defining equations, to supplement it with a missing gastrio-intestinal glucose absorption and to make an implementation of the revised model available on-line to the scientific community.

Laparoscopic vaginal lateral suspension: technical aspects and initial experience

BACKGROUND

Pelvic organ prolapse (POP) etiology is a combination of anatomical, physiological, genetic, lifestyle, and reproductive factors determine pelvic floor dysfunction. POP is very common across all ages women worldwide and has become an increasing socioeconomic problem with public health consequences, with symptoms that could lead to a significant decrease in quality of life.

METHODS

This study retrospectively analyzes a small case series of our initial experience of laparoscopic vaginal suspension with mesh focusing on the technical aspects of the technique. Although sacrocolpopexy and sacrohysteropexy are the most performed surgical techniques, they are associated with serious complications. Laparoscopic vaginal suspension appears reproducible and safe to learn.

RESULTS

Between November 2017 and January 2020, fifteen patients underwent laparoscopic vaginal suspension for pelvic organ prolapse repair. Despite the small number, for a minimally invasive skilled surgeon, we notice a significative reduction of the learning curve to become proficient in this procedure.

CONCLUSIONS

The diagnosis and management of pelvic organ prolapse are further complicated by what is considered "successful" treatment. Laparoscopic vaginal suspension is a feasible surgical procedure for one-stage treatment of pelvic organ prolapse.

Laparoscopic vaginal lateral suspension: technical aspects and initial experience

BACKGROUND

Pelvic organ prolapse (POP) etiology is a combination of anatomical, physiological, genetic, lifestyle, and reproductive factors determine pelvic floor dysfunction. POP is very common across all ages women worldwide and has become an increasing socioeconomic problem with public health consequences, with symptoms that could lead to a significant decrease in quality of life.

METHODS

This study retrospectively analyzes a small case series of our initial experience of laparoscopic vaginal suspension with mesh focusing on the technical aspects of the technique. Although sacrocolpopexy and sacrohysteropexy are the most performed surgical techniques, they are associated with serious complications. Laparoscopic vaginal suspension appears reproducible and safe to learn.

RESULTS

Between November 2017 and January 2020, fifteen patients underwent laparoscopic vaginal suspension for pelvic organ prolapse repair. Despite the small number, for a minimally invasive skilled surgeon, we notice a significative reduction of the learning curve to become proficient in this procedure.

CONCLUSIONS

The diagnosis and management of pelvic organ prolapse are further complicated by what is considered "successful" treatment. Laparoscopic vaginal suspension is a feasible surgical procedure for one-stage treatment of pelvic organ prolapse.

Pleural catheters after thoracoscopic treatment of malignant pleural effusion: a randomized comparative study on quality of life

Background

Malignant pleural effusion (MPE) complicates many neoplasms and its incidence is expected to rise in parallel with the aging population and longer survival of cancer patients. Although a clear consensus exists on indwelling catheters in patients with poor performance status, no study has hitherto compared different devices in patients requiring temporary or definitive drainage following talc poudrage.

Methods

This is a prospective, two-arm, pilot study on patients with MPE undergoing talc poudrage, comparing two different catheters (PleurX^® versus Pleurocath^®) positioned because of the inefficacy of the procedure or the high risk of short-term failure. End points of the study were quality of life (QoL), median dyspnea and chest pain assessment by EORTC questionnaires and a 100 mm visual analog scale, total in-hospital length of stay and frequency of serious adverse events.

Results

No difference was observed between the two groups in in mean dyspnea and mean chest pain in any questions of the EORTC QLQ-C30 and QLQ-LC13 questionnaires. Duration of the procedure was significantly longer in the PleurX^® group versus the Pleurocath^® group (72±33 versus 44±13 minutes; P=0.03). No difference was observed between the two groups in total length of hospital stay (P=1.00) or complication rate (P=1.00).

Conclusions

For the cohort of patients still needing indwelling pleural catheters (PC) after thoracoscopic talc poudrage, PleurX^® is suggested when drain removal is unlikely due to short life expectancy or the high chance of pleurodesis failure. Conversely, Pleurocath^® should be recommended in all other patients as it is faster to place and easier to remove.

Keywords

Malignant pleural effusion (MPE); talc poudrage; indwelling pleural catheter (indwelling PC).

Impact of negative feedback in metabolic noise propagation

Synthetic biology combines different branches of biology and engineering aimed at designing synthetic biological circuits able to replicate emergent properties useful for the biotechnology industry, human health and environment. The role of negative feedback in noise propagation for a basic enzymatic reaction scheme is investigated. Two feedback control schemes on enzyme expression are considered: one from the final product of the pathway activity, the other from the enzyme accumulation. Both schemes are designed to provide the same steady-state average values of the involved players, in order to evaluate the feedback performances according to the same working mode. Computations are carried out numerically and analytically, the latter allowing to infer information on which model parameter setting leads to a more efficient noise attenuation, according to the chosen scheme. In addition to highlighting the role of the feedback in providing a substantial noise reduction, our investigation concludes that the effect of feedback is enhanced by increasing the promoter sensitivity for both schemes. A further interesting biological insight is that an increase in the promoter sensitivity provides more benefits to the feedback from the product with respect to the feedback from the enzyme, in terms of enlarging the parameter design space.

Peripheral Paraneoplastic Neuropathy, an Uncommon Clinical Onset of Sigmoid Cancer. Case Report and Review of the Literature

A case of a 76-year-old man presenting with weakness of the lower legs and bilateral steppage gait is described. Neurological examination revealed a sensorimotor neuropathy with axonopathy and myelinic aspects. At the time of the diagnostic workup an episode of rectal bleeding occurred. Colonoscopy demonstrated an exophytic cancer of the sigmoid colon at 40 cm from the anal verge. At surgery the tumor adhered to the ileum, so a left hemicolectomy and ileo-ileal resection were performed. Tumor stage was Dukes' B, Jass III, Astler-Coller B2, T3N0M0. The patient underwent postoperative chemotherapy and was followed for the past three years. At present he is free of disease and the neuropathy has completely regressed without any dedicated therapy.

As reported in the literature the appearance of a paraneoplastic neurological syndrome (PNS) may be the first sign of a malignancy that is occult at the time of clinical presentation. The most widely supported theory about its etiology is that of an autoimmune origin. The paraneoplastic neurological syndrome is considered to be at a point of intersection between tumor immunology, autoimmune neurological disease, and basic neurobiology. Previous experience has resulted in a pathogenic model and in a definition of a group of autoantibodies related to the disease. Small cell lung cancer (SCLC) is the neoplasm most frequently associated with PNS; other malignancies include lymphomas and various hematological malignancies. Some authors reported also that the percentage of patients with a high titer of neuronal autoantibodies is small and several of the autoantibodies are present at low levels without any accompanying clinical manifestation. In a clinical retrospective study of the Mayo Clinic Group 115,081 patients were examined over the period 1984-1993 and only 58 patients (0.05%) could be defined as being affected by a paraneoplastic neurological syndrome. Only five of these patients had colon tumors. The number of patients is so small and so widely scattered among publications that no statistical analysis is possible. Probably the only possibility for early identification of such a syndrome is a high degree of suspicion. In fact, these patients are usually first admitted and studied in a neurological unit, and the diagnosis of a tumor-associated disease is a delayed event.

Ten Years' Experience in Robotic-Assisted Thoracic Surgery for Early Stage Lung Cancer

BACKGROUND

 This study analyzed the short- and long-term outcomes of robotic-assisted thoracic surgery (RATS) for early stage non-small cell lung cancer (NSCLC).

METHODS

 From November 2006 to December 2016, we performed 363 RATS procedures. This study retrospectively reviewed 339 patients who underwent RATS for clinical stages I (n = 318) or II (n = 21) NSCLC.

RESULTS

 Twenty-nine patients underwent segmentectomy, 307 lobectomy, and 3 pneumonectomy. Conversion occurred in 22 patients (6.5%): 15 (4.4%) due to technical issues, 4 (1.2%) for oncological reasons, and 3 (0.9%) for bleeding. The median number of N1 and N2 stations resected was 2 and 3, respectively, and the median number of N1 and N2 lymph nodes resected was 9 and 6, respectively. Median operative time was 192 minutes for lobectomy, 172 minutes for segmentectomy, and 275 minutes for pneumonectomy. Median length of hospital stay was 5 days (2-191). The most common postoperative complication was prolonged air leak (12.1%). Major complications occurred in eight patients (2.4%). The 30-day and 90-day operative mortality was 0% and 0.3%, respectively. Two and 5-year cancer-specific survival rate was 96.1% and 91.5%, respectively. Five-year survival rate was 96.2% for patients who underwent segmentectomy, and 89.1% for lobectomy. All three patients who underwent pneumonectomy were alive at 5 years with no disease.

CONCLUSIONS

 Besides the well-known short-term outcomes showing very low morbidity and mortality rates, mediastinal lymph node dissection during RATS adequately assesses lymph node stations detecting occult lymph node metastasis and leading to excellent oncologic results. However, these results await longer follow-up studies.

Emergency drain for post pneumonectomy bronchopleural fistula: a drain placement technique based on the siphon principle

Post pneumonectomy bronchopleural fistula (BPF) is a life-threatening complication requiring pleural cavity drainage to avoid acute mediastinal shift and contralateral aspiration pneumonia. Chest drain insertion in this situation may be technically difficult because of drastic anatomical changes such as mediastinal dislocation, diaphragm elevation and, sometimes, massive subcutaneous emphysema. In addition, the most important part of the pleural cavity to be drained is the costophrenic recess that is scarcely drained by a standard chest tube with its tip aiming high and upwards. We propose a safe, simple and effective technique based on the siphon principle to drain the lowest part of the pleural cavity.

Single-Incision Versus Three-Port Laparoscopic Appendectomy: Short- and Long-Term Outcomes

AIM

To compare the outcome of patients who had undergone single-incision laparoscopic appendectomy (SILA) with others who had undergone three-port laparoscopic appendectomy (3-PORT).

MATERIALS AND METHODS

Data from all adults with uncomplicated appendicitis treated by laparoscopic appendectomy between June 2012 and December 2015 were prospectively collected. Patients with chronic pain, appendix malignancy, at least two previous laparotomies, and those undergoing concomitant surgery for different condition were excluded from analysis. Postoperative pain was assessed by a visual analog scale (VAS). Patients were reviewed postoperatively at 7 days and 1 month in the outpatient clinic. Late complications were assessed with a telephonic interview.

RESULTS

A total of 91 patients were included (46 SILA; 45 3-PORT). There were 16 males and 30 females in the SILA group (mean age = 26.76 ± 10.58 years) and 18 males and 27 females in the 3-PORT group (mean age = 26.84 ± 10.79 years). The mean operative time for SILA was 48.54 ± 12.80 min, for the 3-PORT group the mean operative time was 46.33 ± 15.54 min (P = 0.46). No case required conversion. Mean postoperative hospital length of stay was 1.87 ± 0.69 days for SILA and 2.38 ± 1.11 days for 3-PORT (P = 0.01). VAS value of 3.91 ± 1.96 and mean ketorolac usage of 0.38 ± 0.65 in 3-PORT group and SILA patients reported 3.70 ± 1.58 and 0.39 ± 0.58, respectively (P = 0.91). Our mean follow-up in SILA group was 25.75 ± 10.82 months, for 3-PORT group the mean follow-up was 26.9 ± 11.8 months. Eleven patients missed long-term follow-up. No incisional hernia was found. There is a statistically significant difference in cosmetic evaluation in favor of SILA (P < 0.005).

CONCLUSIONS

There was no difference in operative time, early complications, postoperative pain, analgesia requirement between SILA and 3-PORT laparoscopic appendectomy, but after SILA procedure discharge was quicker and long-term cosmetic satisfaction was superior.

New stapling devices in robotic surgery

Minimally invasive thoracic surgery is rapidly diffusing worldwide. Robotic anatomic pulmonary resection is gaining popularity and acceptance in the thoracic community for the reported feasibility, safety, and good outcomes. The last available robotic system, da Vinci Xi System, added new technical improvements on robotic device allowing best performances in robotic lung resection. We report our initial experience in the use of EndoWrist Stapler during robotic anatomic surgery for lung cancer.

Volatile signature for the early diagnosis of lung cancer

Exhaled breath contains hundreds of volatile organic compounds (VOCs). Several independent researchers point out that the breath of lung cancer patients shows a characteristic VOC-profile which can be considered as lung cancer signature and, thus, used for diagnosis. In this regard, the analysis of exhaled breath with gas sensor arrays is a potential non-invasive, relatively low-cost and easy technique for the early detection of lung cancer. This clinical study evaluated the gas sensor array response for the identification of the exhaled breath of lung cancer patients. This study involved 146 individuals: 70 with lung cancer confirmed by computerized tomography (CT) or positron emission tomography-(PET) imaging techniques and histology (biopsy) or with clinical suspect of lung cancer and 76 healthy controls. Their exhaled breath was measured with a gas sensor array composed of a matrix of eight quartz microbalances (QMBs), each functionalized with a different metalloporphyrin. The instrument produces, for each analyzed sample, a vector of signals encoding the breath (breathprint). Breathprints were analyzed with multivariate analysis in order to correlate the sensor signals to the disease. Breathprints of the lung cancer patients were differentiated from those of the healthy controls with a sensitivity of 81% and specificity of 91%. Similar values were obtained in patients with and without metabolic comorbidities, such as diabetes, obesity and dyslipidemia (sensitivity 85%, specificity 88% and sensitivity 76%, specificity 94%, respectively). The device showed a large sensitivity to lung cancer at stage I with respect to stage II/III/IV (92% and 58% respectively). The sensitivity for stage I did not change for patients with or without metabolic comorbidities (90%, 94%, respectively). Results show that this electronic nose can discriminate the exhaled breath of the lung cancer patients from those of the healthy controls. Moreover, the largest sensitivity is observed for the subgroup of patients with a lung cancer at stage I.

A glycemia-structured population model

Structured models are population models in which the individuals are characterized with respect to the value of some variable of interest, called the structure variable. In the present paper, we propose a glycemia-structured population model, based on a linear partial differential equation with variable coefficients. The model is characterized by three rate functions: a new-adult population glycemic profile, a glycemia-dependent mortality rate and a glycemia-dependent average worsening rate. First, we formally analyze some properties of the solution, the transient behavior and the equilibrium distribution. Then, we identify the key parameters and functions of the model from real-life data and we hypothesize some plausible modifications of the rate functions to obtain a more beneficial steady-state behavior. The interest of the model is that, while it summarizes the evolution of diabetes in the population in a completely different way with respect to previously published Monte Carlo aggregations of individual-based models, it does appear to offer a good approximation of observed reality and of the features expected in the clinical setting. The model can offer insights in pharmaceutical research and be used to assess possible public health intervention strategies.

Operative rigid bronchoscopy: indications, basic techniques and results

Palliative airway treatments are essential to improve quality and length of life in lung cancer patients with central airway obstruction. Rigid bronchoscopy has proved to be an excellent tool to provide airway access and control in this cohort of patients. The main indication for rigid bronchoscopy in adult bronchology remains central airway obstruction due to neoplastic or non-neoplastic disease. We routinely use negative pressure ventilation (NPV) under general anaesthesia to prevent intraoperative apnoea and respiratory acidosis. This procedure allows opioid sparing, a shorter recovery time and avoids manually assisted ventilation, thereby reducing the amount of oxygen needed, while maintaining optimal surgical conditions. The major indication for NPV rigid bronchoscopy at our institution has been airway obstruction by neoplastic tracheobronchial tissue, mainly treated by laser-assisted mechanical dissection. When strictly necessary, we use silicone stents for neoplastic or cicatricial strictures, reserving metal stents to cover tracheo-oesophageal fistulae. NPV rigid bronchoscopy is an excellent tool for the endoscopic treatment of locally advanced tumours of the lung, especially when patients have exhausted the conventional therapeutic resources. Laser-assisted mechanical resection and stent placement are the most effective procedures for preserving quality of life in patients with advanced stage cancer.

Operative rigid bronchoscopy: indications, basic techniques and results

Palliative airway treatments are essential to improve quality and length of life in lung cancer patients with central airway obstruction. Rigid bronchoscopy has proved to be an excellent tool to provide airway access and control in this cohort of patients. The main indication for rigid bronchoscopy in adult bronchology remains central airway obstruction due to neoplastic or non-neoplastic disease. We routinely use negative pressure ventilation (NPV) under general anaesthesia to prevent intraoperative apnoea and respiratory acidosis. This procedure allows opioid sparing, a shorter recovery time and avoids manually assisted ventilation, thereby reducing the amount of oxygen needed, while maintaining optimal surgical conditions. The major indication for NPV rigid bronchoscopy at our institution has been airway obstruction by neoplastic tracheobronchial tissue, mainly treated by laser-assisted mechanical dissection. When strictly necessary, we use silicone stents for neoplastic or cicatricial strictures, reserving metal stents to cover tracheo-oesophageal fistulae. NPV rigid bronchoscopy is an excellent tool for the endoscopic treatment of locally advanced tumours of the lung, especially when patients have exhausted the conventional therapeutic resources. Laser-assisted mechanical resection and stent placement are the most effective procedures for preserving quality of life in patients with advanced stage cancer.

Anterior approach for Pancoast tumor resection

Tumors arising anteriorly in the apex of the chest were long considered unresectable because of early invasion of vascular structures limiting radical resection through the conventional Paulson approach. These tumors became operable in 1993 when Dartevelle popularized the cervico-thoracic transclavicular technique for resecting these neoplasms. Since then several different surgical approaches to anterior Pancoast tumors have been proposed, drastically improving the rate of radical resections of these tumors. However, there is no consensus on which anterior surgical approach provides the best access to all of the apical non-small cell lung cancers of the thoracic inlet. Moreover, it is still unclear if integrated neoadjuvant and adjuvant treatments can improve the rates of complete resection, local recurrence and long-term survival.

Bronchovascular reconstruction for lung cancer: does induction chemotherapy influence the outcomes?

BACKGROUND

Bronchoangioplastic interventions (BAIs) for lung cancer are challenging procedures associated with a high risk of postoperative morbidity and mortality. The role of induction chemotherapy (IC) in these patients is debated.

METHODS

We reviewed clinical records of patients who underwent a BAI between 1998 and 2009 using a prospective clinical and operative database.

RESULTS

Among 47 patients (39 men; mean age, 66 years) who underwent BAI, 26 (55.3%) received IC for N2 disease or for locally advanced lung cancer. We performed 35 pulmonary artery (PA) sleeve resections (31 partial and 4 circumferential), 10 PA reconstructions with a pericardial patch (8 autologous, and 2 heterologous), and 2 PA reconstructions using heterologous conduit. The 30-day mortality rate was 4.2% (n=2). Morbidity occurred in 19 (40.4%) patients; 5 patients (10.6%) had major complications (3 [6.4%] patients with fatal bronchovascular fistulas and 1 patient each with cardiac dislocation and acute respiratory distress syndrome) (2.2%). Fourteen patients (29.8%) had minor complications: 6 (12.7%) cardiac, 7 (14.9%) pulmonary, and 1 (2.2%) stroke. IC did not influence the complication rate. Overall 5-year survival and disease-free survival was 39.2% and 36.9%, respectively. Early pathologic stage and the absence of nodal involvement significantly influenced survival (p=0.005 and p=0.002, respectively). Patients receiving IC had a better prognosis (62.7% versus 10.7%; p=0.0003). At multivariate analysis, IC influenced long-term survival (p=0.003 [95% CI, 2.92-8.56]).

CONCLUSIONS

BAIs are feasible and effective surgical procedures with acceptable morbidity and mortality. IC does not influence morbidity and allows good long-term outcomes.

Robotic anatomic segmentectomy of the lung: technical aspects and initial results

BACKGROUND

Robotic lobectomy with radical lymph node dissection is a new frontier of minimally invasive thoracic surgery. Series of sublobar anatomic resection for primary initial lung cancers or for metastasis using video-assisted thoracic surgery have been reported but no cases have been so far reported using the robot-assisted approach. We present the technique and surgical outcome of our initial experience.

METHODS

Clinical data of patients undergoing robotic lung anatomic segmentectomy were retrospectively reviewed. All cases were done using the DaVinci System. A 3- or 4-incision strategy with a 3-cm utility incision in the anterior fourth or fifth intercostal space was performed. Individual ligation and division of the hilar structures was performed using Hem-o-Lok (Teleflex Medical, Research Triangle Park, NC) or endoscopic staplers. The parenchyma was transected with endovascular staplers introduced by the bedside assistant mainly through the utility incision. Systematic mediastinal lymph node dissection or sampling was performed.

RESULTS

From 2008 to 2010, 17 patients underwent a robot-assisted lung anatomic segmentectomy in two centers. There were 10 women and 7 men with a mean age of 68.2 years (range, 32 to 82). Mean duration of surgery was 189 minutes. There were no major intraoperative complications. Conversion to open procedure was never required. Postoperative morbidity rate was 17.6% with pneumonia in 1 case and prolonged air leaks in 2 patients. Median postoperative stay was 5 days (range, 2 to 14), and postoperative mortality was 0%. Final pathology was non-small cell lung cancer in 8 patient, typical carcinoids in 2, and lung metastases in 7.

CONCLUSIONS

Robotic anatomic lung segmentectomy is feasible and safe procedure. Robotic system, by improving ergonomic, surgeon view and precise movements, may make minimally invasive segmentectomy easier to adopt and perform.

Modified Blalock clamp: a single-hand autostatic device for pulmonary vessel occlusion during lung cancer resection

Vascular clamping during lung cancer resection may be difficult in patients with short vessels or large neoplasms preventing adequate and safe exposure. In addition, the physiological vicinity of some vessels to rigid structures like the bronchi may interfere with ideal clamp positioning even in ordinary procedures. We have modified the original Blalock clamp to facilitate the control of pulmonary vessels and physiologically compress the vessel walls, thereby allowing optimal vascular resection and reconstruction during lung cancer surgery. This clamp allows easy, safe and physiological control of pulmonary vessels thanks to its double-branched guillotine mechanism.

Perioperative blood transfusion practices in oncologic thoracic surgery: when, why, and how

INTRODUCTION

Available information on perioperative blood transfusion practices in oncologic thoracic surgery is scant and outdated. The purpose of this study was to investigate transfusion requirements in patients undergoing curative resection for lung cancer and to identify possible factors predictive of perioperative blood transfusion in our cohort of patients.

METHODS

From 1st January 2009 to 31st December 2009, 317 patients underwent anatomic pulmonary resection. Patients who received at least 1 unit of red blood cells comprised the "transfused" group. Each case in this group was matched for surgical procedure with a control subject who did not require blood transfusion and was operated on during the same year; these patients comprised the "not transfused" group.

RESULTS

A total of 75 patients (23.6%) received at least 1 unit of red blood cells during the perioperative period. Factors conditioning perioperative blood transfusion were: preoperative hemoglobin level (p < 0.0001); procedure duration (p = 0.017); body mass index (p < 0.001); induction therapies (p = 0.017); redo procedure (p = 0.021). Age, sex, histology, stage, ASA score, side, intraoperative blood loss, and fluid infusion did not affect perioperative blood transfusion practices.

CONCLUSIONS

Preoperative hemoglobin level is the major risk factor for perioperative blood transfusion practices in oncologic thoracic surgery; procedure duration, body mass index, induction therapies, and redo procedure may condition transfusional needs, although they were actually not predictive on multivariate analysis.

The impact of preoperative body mass index on respiratory complications after pneumonectomy for non-small-cell lung cancer. Results from a series of 154 consecutive standard pneumonectomies

OBJECTIVE

Although it may seem intuitive that obesity is an additional risk factor for surgical patients, few studies have correlated this condition with lung cancer resection. The only data currently available suggest that obesity does not increase the rate of complications after anatomic resection for non-small-cell lung cancer (NSCLC).

METHODS

We enrolled 154 consecutive patients undergoing standard pneumonectomy for NSCLC at the Department of Thoracic Surgery of the European Institute of Oncology from January 2004 to April 2008. To determine the influence of preoperative body mass index (BMI) on postoperative complications, patients were classified into two groups: (1) BMI ≥ 25 kg m⁻²; n = 93 (60.4%); and (2) BMI < 25 kg m⁻²; n = 61 (39.6%). Data on sex, age, cigarette smoking, preoperative albumin, total proteins and creatinine values, forced expiratory volume in 1s percentage (FEV1%), diffusion lung capacity for carbon monoxide/alveolar volume percentage (DLCO/AV%) and histology and pathological stage were collected. Information on total postoperative complications, 30-day mortality rate, specific pulmonary and cardiac complications, intensive care unit (ICU) admission and hospital stay was collected and analysed for the BMI group.

RESULTS

Among the 154 operated patients, 30 (19.5%) were women with a mean age of 63.4 years (range: 36-82). As many as 136 (88.3%) patients were smokers or former smokers; 80 patients (51.9%) received presurgical treatment. A total of 64 (41.6%) right pneumonectomy procedures were performed. Mean ± SD for preoperative variables were FEV1%: 83.5 ± 19.2, DLCO/AV: 85.4% ± 20.3, albumin: 4.07 ± 0.44 g dl(-1), total proteins: 7.23 ± 0.59 g dl⁻¹, creatinine: 0.81 ± 0.23 mg dl⁻¹. Ten patients died within the first 30 days (30-day mortality: 6.5%). The male sex was significantly more prevalent in the high BMI group (p=0.039). The preoperative mean creatinine value was significantly higher in the high BMI group (0.86 mg dl(-1) vs 0.75 mg dl⁻¹, p=0.002) and preoperative DLCO/AV values were better in the high BMI group than in the BMI group < 25 kg m⁻² (79.9 vs 88.8, p = 0.009). The high BMI group had a higher incidence of respiratory complications (21.5% vs 4.9% p = 0.005, odds ratio (OR) = 5.3, 95% confidence interval (CI): 1.5, 18.7). No significant differences were observed between the two groups regarding ICU admission, hospital stay, 30-day mortality and total and specific cardiac complications.

CONCLUSIONS

The risk of respiratory complications in patients with BMI higher than 25 kg m⁻² undergoing pneumonectomy for lung cancer is 5.3 times higher than that of patients with BMI < 25 kg m⁻². Thoracic surgeons and anaesthesiologists should be aware of this information before planning elective pneumonectomy in overweight and especially in obese patients.

Synchronous pleuro - renal solitary fibrous tumors: a new clinical-pathological finding

Solitary fibrous tumors of the pleura (SFTP) are rare mesenchymal neoplasms usually originating from the visceral pleura, but sometimes found in other sites like the orbit, dura, paranasal sinus, upper respiratory tract, thyroid, sublingual gland, lung, periosteum, cauda equina, ovary, scrotum and testicular tunica vaginalis. Solitary fibrous tumor of the kidney is extremely rare with fewer than 15 reported cases in modern English literature. To the best of our knowledge, this report describes the first known case of synchronous SFTP in the left parietal pleura and left kidney. The SFTP of the pleura, widely compressing and displacing the left lower lung lobe, was resected via left thoracotomy, whereas the renal SFTP, diagnosed by echo-guided histological biopsy, was closely monitored by computed tomography scan and ultrasound. After a one-year follow-up no recurrence was detected in the left hemithorax and the renal lesion remained stable.

Vascular catheter mimicking persistent left superior vena cava

We report the case of a 42-year-old woman with a double vascular catheter mimicking a false persistent left superior vena cava on a chest X-ray. Physicians should be aware of the correct course of these catheters in order to avoid serious clinical consequences.