The Legend of the Buffalo Chest.

BACKGROUND: The "buffalo chest" is a condition in which a simultaneous bilateral pneumothorax occurs due to a communication of both pleural cavities caused by an iatrogenic or idiopathic fenestration of the mediastinum. This rare condition is known by many clinicians because of a particular anecdote which stated that Native Americans could kill a North American bison with a single arrow in the chest by creating a simultaneous bilateral pneumothorax, due to the animal's peculiar anatomy in which there is one contiguous pleural space due to an incomplete mediastinum. RESEARCH QUESTION: What evidence is there for the existence of buffalo chest? STUDY DESIGN AND METHODS: The term "buffalo chest" and its anecdote were first mentioned in a ''personal communication'' by a veterinarian in the Annals of Surgery in 1984. A mixed method research was performed on buffalo chest and its etiology. A total of 47 cases of buffalo chest were identified in humans. RESULTS: This study found that all authors were referring to the article from 1984 or to each other. Evidence was found for interpleural communications in other mammal species, but no literature on the anatomy of the mediastinum of the bison was found. The main reason for this research was fact-checking the origin of the anecdote and search for evidence for the existence of buffalo chest. Autopsies were performed on eight bison, and four indeed were found to have had interpleural communications. INTERPRETATION: We hypothesize that humans can also have interpleural fenestrations, which can be diagnosed when a pneumothorax occurs.

Pleural function and lymphatics.

The pleural space plays an important role in respiratory function as the negative intrapleural pressure regimen ensures lung expansion and in the mean time maintains the tight mechanical coupling between the lung and the chest wall. The efficiency of the lung-chest wall coupling depends upon pleural liquid volume, which in turn reflects the balance between the filtration of fluid into and its egress out of the cavity. While filtration occurs through a single mechanism passively driving fluid from the interstitium of the parietal pleura into the cavity, several mechanisms may co-operate to remove pleural fluid. Among these, the pleural lymphatic system emerges as the most important one in quantitative terms and the only one able to cope with variable pleural fluid volume and drainage requirements. In this review, we present a detailed account of the actual knowledge on: (a) the complex morphology of the pleural lymphatic system, (b) the mechanism supporting pleural lymph formation and propulsion, (c) the dependence of pleural lymphatic function upon local tissue mechanics and (d) the effect of lymphatic inefficiency in the development of clinically severe pleural and, more in general, respiratory pathologies.

Anatomy and pathophysiology of the pleura and pleural space.

Pleural effusions are most often secondary to an underlying condition and may be the first sign of the underlying pathologic condition. The balance between the hydrostatic and oncotic forces dictates pleural fluid homeostasis. The parietal pleura has a more significant role in pleural fluid homeostasis. Its vessels are closer to the pleural space compared with its visceral counterpart; it contains lymphatic stomata, absent on visceral pleura, which are responsible for a bulk clearance of fluid. The diagnosis and successful treatment of pleural effusions requires a mixture of imaging techniques and pleural fluid analysis.

Anatomy of the pleura.

The pleura is a monolayer of mesothelial cells covering the lung and inner surface of the chest cavity, creating the pleural space. The mesothelial cells rest on a matrix of collagen, elastic fibers, blood vessels, and lymphatics, which allow the lung and chest to expand and contract, protected from friction by the pleural fluid and properties of the mesothelial cells. With a rich blood supply and lymphatic system just deep to the mesothelial layer, the pleura is a dynamic layer protecting the lung and pleural cavity from infection while transmitting the forces of respiration without damage to the underlying lung parenchyma.

Correlative anatomy of the pleura and pleural spaces.

Although pleural disorders are commonly encountered in the daily practices of thoracic surgeons, their assessment can be difficult. Being able to correlate normal and abnormal anatomy with imaging characteristics provides additional information that can be useful not only to accurately locate pleuropulmonary lesions but also to characterize abnormalities, such as pleural thickening or malignant processes.

Left costomediastinal recess of the pleura, the potential pleural space anterior to the heart.

OBJECTIVE: To investigate clinical implications of the left costomediastinal recess of the pleura. METHODS: The left anterior pleural anatomy was studied in 12 cadavers. Chest computed tomography (CT) scans of 68 healthy/near-healthy patients were reviewed for the recess. Twenty pleural lesions in the recess were analyzed on CT. Eight cases of left paracardiac pericardiocentesis were analyzed for pleural complications. RESULTS: Two fresh cadavers showed the recess to be wider downward, measuring 75 and 55 mm in width at the sixth intercostal space. None of the 68 healthy/near- healthy CT scans displayed the recess. Twenty recess lesions were connected to similar pleural lesions surrounding the left lung (n = 19) or showed an isolated lesion therein only partly facing the left lung (n = 1). Ipsilateral pleural effusion complicated 3 of 7, successful left paracardiac pericardiocentesis. CONCLUSION: Regardless of their contiguity with the lung, the differential diagnosis of precordial lesions should include pleural diseases in the recess. Left anterior pericardiocentesis unavoidably violates the intervening recess, sometimes causing pleural effusion.

Bilateral primary spontaneous pneumothorax: buffalo chest.

A case of bilateral primary spontaneous pneumothorax ("buffalo chest") in a previously healthy man is described. The clinical presentation and treatment options are discussed.

In vivo three-dimensional imaging of normal tissue and tumors in the rabbit pleural cavity using endoscopic swept source optical coherence tomography with thoracoscopic guidance.

The purpose of this study was to develop a dynamic tunable focal distance graded-refractive-index lens rod-based high-speed 3-D swept-source (SS) optical coherence tomography (OCT) endoscopic system and demonstrate real-time in vivo, high-resolution (10-microm) imaging of pleural-based malignancies in an animal model. The GRIN lens-based 3-D SS OCT system, which images at 39 fps with 512 A-lines per frame, was able to capture images of and detect abnormalities during thoracoscopy in the thoracic cavity, including the pleura, chest wall, pericardium, and the lungs. The abnormalities were confirmed by histological evaluation and compared to OCT findings. The dynamic tunable focal distance range and rapid speed of the probe and SS prototype OCT system enabled this first-reported application of in vivo 3-D thoracoscopic imaging of pleural-based malignancies. The imaging probe of the system was found to be easily adaptable to various sites within the thoracic cavity and can be readily adapted to other sites, including rigid airway endoscopic examinations.

Potential foramen to allow communication between the pleural cavity and retroperitoneal space during laparoscopic surgery: a cadaver study of Bochdalek's triangle.

The indications for laparoscopic retroperitoneal surgery have recently been greatly extended and the technique has become popular, but concomitant pleural injury or pneumothorax has been reported from numerous hospitals in Japan. Which anatomical information is useful to avoid surgical injury of the suggested weak portion of the diaphragm? We identified a diaphragm-free triangular area or Bochdalek's triangle in 90.1% of elderly Japanese cadavers (100/111 cadavers), comprising about 622.8 mm(2) in area (height 47.9 mm, base 25.0 mm). In most cases (80.1%; 129/161), the entire triangle was restricted to the superior side of the 12th rib in addition to the medial side of the distal end of the rib. A "potential foramen" (PF) was defined as the diaphragm-free triangle >100 mm(2) in area on the parietal pleura. Most triangles (77.6%, 125/161) met this criterion. The PF was often covered by the kidney (93.3%), and had a mean area of 318.9 mm(2). The PF was located 42.3 mm from the distal end of the 12th rib, while the inferior pleural margin was 27.8 mm superior to the rib end. When the triangle was large, the PF was also large, with the PF often occupying >50% of the triangle area (62/125; 49.6%). To avoid the distal end of the 12th rib, in laparoscopic retroperitoneal surgery, we recommend making a transverse skin incision at the midpoint between the end of the 12th rib and the iliac crest.

[Computed tomographic anatomy of the intercostal space and the pleura. Pleural plaques: positive and differential diagnosis]. / Anatomie tomodensitométrique de l'espace intercostal et de la plèvre. Plaques pleurales: diagnostic positif et diagnostic différentiel.

Diagnosis of pleural plaques depends on adequate knowledge of the normal anatomy of the pleura and intercostals spaces which is indispensable for understanding the normal computed tomographic images of the thorax and anatomic variants.

Sentinel lymph node mapping of the pleural space.

STUDY OBJECTIVES: Although the sentinel lymph node (SLN) concept has traditionally been applied to solid organs, we hypothesized that the pleural space might drain into a specific SLN group. The identification of such a nodal group could assist in the staging and treatment of pleural-based diseases, such as mesothelioma, or other lung cancers with visceral pleural invasion. The purpose of this study was to determine whether the pleural space has an SLN group. DESIGN: Sixteen rats underwent right or left pleural space injection of a novel lymph tracer, quantum dots (QDs), which have a hydrodynamic diameter of 15 nm and fluoresce in the near-infrared (NIR) spectrum. Nodal uptake of the entire thorax was imaged with a custom system that simultaneously acquired color video, NIR fluorescence of the QDs, and a merged picture of the two in real-time. Six pigs underwent right or left pleural space injection of QDs and similar imaging. MEASUREMENTS AND RESULTS: In the rat, the QDs drained solely to the highest superior mediastinal lymph node group, corresponding to lymph node station 1, according the regional lymph node classification for lung of the American Joint Committee on Cancer. In one rat, the injection of QDs in the left pleural space resulted in migration to the contralateral station 1 lymph node group. The injection of QDs in the right or left pleural space of the pig resulted in migration solely to the ipsilateral highest superior mediastinal lymph node group. CONCLUSIONS: NIR fluorescence imaging in two species demonstrated that the highest superior mediastinal lymph nodes of station 1 are the SLNs of the pleural space. This study also provides intraoperative feasibility and proof of the concept for identifying lymph nodes communicating with the pleural space on a patient-specific basis, in real-time, and with high sensitivity.

In vivo optical imaging of pleural space drainage to lymph nodes of prognostic significance.

BACKGROUND: Understanding the spatial and temporal drainage patterns of the pleural space could have profound impact on the treatment of lung cancer and mesothelioma. The purpose of this study was to identify the in vivo pattern of drainage from the pleural space to prognostic lymph node stations. METHODS: Fifty-six rats underwent pleural space injection of a novel lymph tracer composed of recombinant human serum albumin (HSA) covalently conjugated to the near-infrared (NIR) fluorophore IRDye78 via an amide bond (HSA-78). Nodal uptake was imaged at 10, 20, 30, and 60 minutes and 4, 12, and 24 hours after injection with a custom system that simultaneously acquires color video, NIR fluorescence of HSA-78, and a merged picture of the two. Six pigs underwent the same procedure with imaging at 30 minutes, 1 hour, and 24 hours. RESULTS: In both the rat model and the pig model, HSA-78 drained from the pleural space to superior mediastinal lymph nodes first, followed by other intrathoracic and then extrathoracic lymph nodes over the course of 24 hours. CONCLUSION: NIR fluorescence imaging in two species shows that the superior mediastinal lymph nodes are the first to drain the pleural space. Over the course of 24 hours, the pleural space also communicates with other intrathoracic and then extrathoracic lymph nodes. This study also demonstrates an intraoperative method for identifying nodes communicating with the pleural space, with potential utility in the staging and/or resection of lung cancer and mesothelioma.

Anatomical basis for a successful upper limb sympathectomy in the thoracoscopic era.

In this clinico-anatomical study, factors potentially responsible for unsuccessful upper limb sympathectomy (ULS) by the thoracoscopic route were evaluated. This study comprised two subsets: 1) in the clinical subset, 25 patients (n = 50 sides) underwent bilateral second thoracic ganglionectomy for palmar hyperhidrosis, and factors predisposing to unsuccessful ULS were identified; and 2) in the anatomical subset, the neural connections of the first and second intercostal spaces were bilaterally dissected in 22 adult cadavers (22 right, 21 left; n = 43 sides). Alternate neural pathways (ANP) were noted in 9 of 50 sides in the 25 clinical cases (18%). In three asthenic patients (5 sides), fascia overlying the longus colli muscle mimicked the sympathetic chain. The right superior intercostal vein (SIV) was located anterior to the second thoracic ganglion in 6 of 50 sides (12%) and predisposed to troublesome bleeding in 2 of 50 cases; the SIV was posterior to the ganglion in 19 of 50 sides (38%), posing no technical problem. On the left, the SIV was noted outside the field of dissection in all but one case. A successful outcome to sympathectomy was noted in all 25 patients. A spectrum of sympathetic contributions to the first thoracic ventral ramus for the first intercostal space was noted in 37 of 43 anatomical cases (86%). These were categorized according to the arrangements of the intrathoracic ramus between the second intercostal nerve and the first thoracic ventral ramus. The cervicothoracic ganglion (37/43 cases; 86%) and an independent inferior cervical ganglion (6/43 cases; 14%) were always located above the second rib. The second thoracic ganglion was consistently located in the second intercostal space. This study demonstrates that ANPs have little clinical significance when a second thoracic ganglionectomy is undertaken. Technical failures may be avoided if the surgeon is mindful of anatomical variations at surgery.

Intermittent or continuous carbon dioxide insufflation for de-airing of the cardiothoracic wound cavity? An experimental study with a new gas-diffuser.

Insufflation of carbon dioxide into the chest wound is used in open-heart surgery to de-air the heart and great vessels. In a cardiothoracic wound model, we compared the degree of air displacement achieved by a new insufflation device, a gas-diffuser, with that of a thin open-ended tube during steady-state and with carbon dioxide flows of 2.5, 5, 7.5, and 10 L/min. We also studied air displacement at the start of and after discontinuation of carbon dioxide insufflation with the gas-diffuser and evaluated the influence of an open pleura. During steady state, the gas-diffuser produced efficient air displacement in the wound cavity model at carbon dioxide flows of > or = 5 L/min (< or = 0.65% remaining air), whereas the open-ended tube was inefficient (> or = 82% remaining air) at all studied carbon dioxide flows (P < 0.001). An open pleural cavity prolonged the time needed to obtain a high degree of air displacement in the wound cavity (P = 0.001). Carbon dioxide insufflation of the cardiothoracic wound cavity should be initiated at a carbon dioxide flow of 10 L/min at least 1 min before the incision of the heart and great vessels and should be continued at a carbon dioxide flow of at least 5 L/min until surgical closure.