Pelvic Retroperitoneal Dissection: A Hands-on Primer.

This article is a personal perspective of female surgical pelvic anatomy and recommended surgical dissection techniques.

Persistent pneumocystis colonization leads to the development of chronic obstructive pulmonary disease in a nonhuman primate model of AIDS.

Human immunodeficiency virus (HIV)-infected patients are at increased risk for development of pulmonary complications, including chronic obstructive pulmonary disease (COPD). Inflammation associated with subclinical infection has been postulated to promote COPD. Persistence of Pneumocystis is associated with HIV infection and COPD, although a causal relationship has not been established. We used a simian/human immunodeficiency virus model of HIV infection to study pulmonary effects of Pneumocystis colonization. Simian/human immunodeficiency virus-infected/Pneumocystis-colonized monkeys developed progressive obstructive pulmonary disease characterized by increased emphysematous tissue and bronchial-associated lymphoid tissue. Increased levels of T helper type 2 cytokines and proinflammatory mediators in bronchoalveolar lavage fluid coincided with Pneumocystis colonization and a decline in pulmonary function. These results support the concept that an infectious agent contributes to the development of HIV-associated lung disease and suggest that Pneumocystis colonization may be a risk factor for the development of HIV-associated COPD. Furthermore, this model allows examination of early host responses important to disease progression, thus identifying potential therapeutic targets for COPD.

The nature of small-airway obstruction in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major public health problem associated with long-term exposure to toxic gases and particles. We examined the evolution of the pathological effects of airway obstruction in patients with COPD. METHODS: The small airways were assessed in surgically resected lung tissue from 159 patients--39 with stage 0 (at risk), 39 with stage 1, 22 with stage 2, 16 with stage 3, and 43 with stage 4 (very severe) COPD, according to the classification of the Global Initiative for Chronic Obstructive Lung Disease (GOLD). RESULTS: The progression of COPD was strongly associated with an increase in the volume of tissue in the wall (P<0.001) and the accumulation of inflammatory mucous exudates in the lumen (P<0.001) of the small airways. The percentage of the airways that contained polymorphonuclear neutrophils (P<0.001), macrophages (P<0.001), CD4 cells (P=0.02), CD8 cells (P=0.038), B cells (P<0.001), and lymphoid aggregates containing follicles (P=0.003) and the absolute volume of B cells (P=0.03) and CD8 cells (P=0.02) also increased as COPD progressed. CONCLUSIONS: Progression of COPD is associated with the accumulation of inflammatory mucous exudates in the lumen and infiltration of the wall by innate and adaptive inflammatory immune cells that form lymphoid follicles. These changes are coupled to a repair or remodeling process that thickens the walls of these airways.

Changing the way we train gynecologic surgeons.

To ensure the integrity of gynecologic surgical practices and patient safety, changes need to be made in the training of gynecologic surgeons, both in residency and continuing surgical education. Although society demands competency in the training and continuing education of airline pilots, little is done in comparison to ensure competency in the training and continuing education of gynecologic surgeons. Both professions rely on safe performance to protect the well-being of individuals. It is now time for medical and surgical education to move from the shadows of its "trust me" attitude into the light of a "test me and prove me" criterion.

Use of CT morphometry to detect changes in lung weight and gas volume.

STUDY OBJECTIVES: CT estimates of lung density have been used to estimate the extent and severity of emphysema. The present study was designed to test the hypothesis that quantitative CT can track the changes that occur in diffuse lung disease. DESIGN: The study was based on five patients with pulmonary alveolar proteinosis (PAP) who underwent lung lavage. Pulmonary function was measured before and after each individual lung lavage, and the CT scans before and after lavage were used to compare total lung volume, airspace volume, lung weight, and regional lung inflation. The dry weight of proteinaceous material lavaged from the lung was measured and compared to the change in CT lung weight. RESULTS: All the patients showed improvements in dyspnea, percentage of predicted diffusion capacity of the lung for carbon monoxide, and FVC. There was no change in CT-measured total lung volume or airspace volume, but there was a reduction in lung weight following lavage (p = 0.001), which correlated with the dry weight of the lavage effluent (R(2) = 0.73). Therefore, there was a shift in the regional lung inflation toward a more inflated lung with a corresponding increase in the mean lung inflation (p = 0.001). CONCLUSION: These data show that quantitative CT can objectively track the changes in lung weight and airspace inflation produced by a standard intervention in PAP, and we postulate that it can provide similar information about the progression of other diffuse lung diseases.

Training the gynecologic surgeon.

Educators in obstetrics and gynecology are concerned that the surgical training of residents is not sufficient to meet the needs of new graduates. Since the current standards for time and requirements in training were established, our specialty has greatly increased its body of knowledge, expanded the number and variety of procedures performed, and become more business oriented. With the current emphasis on evidence-based decision making, shouldn't this same philosophy guide the education of future gynecologic physicians and surgeons? This presentation discusses resident teaching, curriculum, and time in training and challenges educational leaders to apply the same robust standards appropriate for scientific investigation to resident education.

Quantitative computed tomography of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is described as airflow limitation that is not fully reversible. Quantitative assessment of structural changes within the lung that are responsible for this airflow limitation has relied on the examination of tissue obtained from surgical or postmortem specimens. However, in the past two decades, researchers have developed novel and robust tools to measure the structure of the lung parenchyma and airway wall by using computed tomographic (CT) scans, which do not require the removal of lung tissue. These techniques are extremely important because they allow longitudinal studies of the pathogenesis of COPD and the assessment of therapeutic interventions. Another application of this approach is that it potentially allows phenotyping of individuals who predominately have emphysema or small-airway disease, which may be important for the evaluation of pathogenesis and prescription of treatment options. This review describes some of these CT techniques for quantitative assessment of lung structure.

Furuncular myiasis secondary to Dermatobia hominis.

Dermatobia homininis is the most common cause of furuncular myiasis in Central and South America. It is diagnosed based on a history of travel to an endemic region and the characteristic cutaneous lesion. We present a 54-year-old patient who presented with both a travel history and cutaneous findings of furuncular myiasis.

Enhanced alveolar clearance with chest percussion therapy and positional changes during whole-lung lavage for alveolar proteinosis.

Pulmonary alveolar proteinosis has traditionally been treated with whole-lung lavage (WLL). The literature describes a variety of techniques used in performing the WLL, including mechanical vs manual chest percussion, use of prone positioning, and variances in lavage volume. We have quantified and compared the effective alveolar clearance for each component of the lavage by measuring the dry weight of material in the lavage effluent. We measured this in five patients who underwent six consecutive WLLs at the University of Pittsburgh Medical Center. We performed the lavage in the following three stages: stage I, passive drainage; stage II, assisted clearance; and stage III, positional clearance. Aliquots of lavage effluent were centrifuged to determine the dry weight of material present in sequentially recorded bottles within each stage. At the initiation of each augmentation, there was a statistically significant improvement in the clearance of material (stage II, p = 0.009; stage III, p = 0.012). Furthermore, we show that lipoproteinaceous material is present in the lavage effluent in all stages of latter portions of the lavage. The effective removal of material would be expected to have an impact on the physiologic and clinical response to WLL. This finding emphasizes the importance of performing an adequate and standardized lavage.

Automated lung segmentation in X-ray computed tomography: development and evaluation of a heuristic threshold-based scheme.

RATIONALE AND OBJECTIVES: To develop and evaluate a reliable, fully-automated lung segmentation scheme for application in X-ray computed tomography. MATERIALS AND METHODS: The automated scheme was heuristically developed using a slice-based, pixel-value threshold and two sets of classification rules. Features used in the rules include size, circularity, and location. The segmentation scheme operates slice-by-slice and performs three key operations: (1) image preprocessing to remove background pixels, (2) computation and application of a pixel-value threshold to identify lung tissue, and (3) refinement of the initial segmented regions to prune incorrectly detected airways and separate fused right and left lungs. RESULTS: The performance of the automated segmentation scheme was evaluated using 101 computed tomography cases (91 thick slice, 10 thin slice scans). The 91 thick cases were pre- and post-surgery from 50 patients and were not independent. The automated scheme successfully segmented 94.0% of the 2,969 thick slice images and 97.6% of the 1,161 thin slice images. The mean difference of the total lung volumes calculated by the automated scheme and functional residual capacity plus 60% inspiratory capacity was -24.7 +/- 508.1 mL. The mean differences of the total lung volumes calculated by the automated scheme and an established, commonly used semi-automated scheme were 95.2 +/- 52.5 mL and -27.7 +/- 66.9 mL for the thick and thin slice cases, respectively. CONCLUSION: This simple, fully-automated lung segmentation scheme provides an objective tool to facilitate lung segmentation from computed tomography scans.

The core of a competent surgeon: a working knowledge of surgical anatomy and safe dissection techniques.

The competent gynecologic surgeon has a sure, working knowledge of the anatomy in the field of pelvic dissection and is expert in the techniques and in the millimeter by millimeter progression of surgical dissections. When operating in the pelvis, the surgeon always asks several questions. The first is, "In what anatomic area am I dissecting?" This question defines the anatomy to be dissected out. The second is,"What dissection techniques will I use here?" The measured steps of surgical dissection give the surgeon the confidence to proceed with the operation, while safeguarding the integrity of the surrounding anatomic structures. With less blood loss and less trauma to the tissues and anatomic structures, the surgeon may expect a better surgical outcome for the patient.

Survival after lung volume reduction in chronic obstructive pulmonary disease: insights from small airway pathology.

RATIONALE: COPD is associated with reduced life expectancy. OBJECTIVES: To determine the association between small airway pathology and long-term survival after lung volume reduction in chronic obstructive pulmonary disease (COPD) and the effect of corticosteroids on this pathology. METHODS: Patients with severe (GOLD-3) and very severe (GOLD-4) COPD (n = 101) were studied after lung volume reduction surgery. Respiratory symptoms, quality of life, pulmonary function, exercise tolerance, chest radiology, and corticosteroid treatment status were assessed preoperatively. The severity of luminal occlusion, wall thickening, and the presence of small airways containing lymphoid follicles were determined in resected lung tissue. Kaplan-Meier survival analysis and Cox proportional hazards models were used to determine the relationship between survival and small airway pathology. The effect of corticosteroids on this pathology was assessed by comparing treated and untreated groups. MEASUREMENTS AND MAIN RESULTS: The quartile of subjects with the greatest luminal occlusion, adjusted for covariates, died earlier than subjects who had the least occlusion (hazard ratio, 3.28; 95% confidence interval, 1.55-6.92; P = 0.002). There was a trend toward a reduction in the number of airways containing lymphoid follicles (P = 0.051) in those receiving corticosteroids, with a statistically significant difference between the control and oral +/- inhaled corticosteroid-treated groups (P = 0.019). However, corticosteroid treatment had no effect on airway wall thickening or luminal occlusion. CONCLUSIONS: Occlusion of the small airways by inflammatory exudates containing mucus is associated with early death in patients with severe emphysema treated by lung volume reduction surgery. Corticosteroid treatment dampens the host immune response in these airways by reducing lymphoid follicles without changing wall thickening and luminal occlusion.

New concepts in the radiological assessment of COPD.

Chronic obstructive pulmonary disease (COPD) is a complex genetic disorder in which environmental factors, such as tobacco smoke, interact with genetic susceptibility to cause disease. Airway obstruction in COPD is due to an exaggerated inflammatory response that ultimately destroys the lung parenchyma (emphysema) and increases airway resistance by remodeling the airway wall. Until recently, assessment of these disease processes required the examination of resected tissue. However, computed tomography (CT) now allows researchers to measure the structure of the lung parenchyma and airway wall without having to remove the tissue. This review describes some of the new CT techniques for quantitative assessment of lung structure. These techniques are extremely important to study the pathogenesis of COPD as well as differentiate patients with predominantly emphysema disease from those with airway wall remodeling, and to assess the effects of therapeutic interventions.

Size and morphology of the trachea before and after lung volume reduction surgery.

OBJECTIVE: The purpose of this investigation was to determine the effect of lung volume reduction surgery on measured tracheal features. MATERIALS AND METHODS: Twenty-four male and 19 female patients with emphysema underwent lung volume reduction surgery, pulmonary function testing, and repeated CT. The tracheal air column was segmented from axial images. The sagittal and coronal dimensions of the intrathoracic trachea were determined. Tracheal morphology was quantified using the tracheal (coronal and sagittal dimensions) and circularity indexes. The results were compared with pulmonary function test results. RESULTS: Morphologic appearance of the intrathoracic trachea was consistent before and 3 months after surgery. The group means of the tracheal length, mean area, and volume were 78.60 mm (+/- 16.88 mm), 283.84 mm(2) (+/- 61.47 mm(2)), and 22.59 cm(3) (+/- 7.69 cm(3)), respectively, before surgery and 67.53 mm (+/- 15.78 mm), 309.12 mm(2) (+/- 79.83 mm(2)), and 20.99 cm(3) (+/- 7.27 cm(3)), respectively, after surgery (p < 0.05). Mean tracheal indexes were 0.85 (+/- 0.11) before surgery and 0.82 (+/- 0.04) after surgery (p < 0.01). Mean circularity indexes were 0.91 (+/- 0.03) before surgery and 0.90 (+/- 0.04) after surgery (p < 0.05). The size of the trachea was significantly correlated with lung volume before and after surgery (p < 0.05). The changes in tracheal features and changes in pulmonary function were not correlated (p > 0.05), except for tracheal area (p < 0.05). CONCLUSION: Our data suggest that tracheal dimensions reflect the severity of emphysema as reflected by increased lung volumes. Tracheal features were poor predictors of changes in postsurgical pulmonary function parameters evaluated in this preliminary study.