A patient demonstrating a barrel chest is most likely suffering from which cardiopulmonary disease?

Chest Wall Deformity

Chest wall deformity has been mentioned by some authors, but did not draw much attention compared with forearm and elbow deformities (Figure 20.9). Arundel et al. described it as a bell-shaped chest wall,42 and Fleming et al. described the upper five ribs on both sides as showing acute angulation medially close to the costovertebral junction.43 Kim et al. counted a pyramidal-shaped chest as one of the characteristic radiographic signs of OI type V, and reported a distinctly abnormal course of ribs in 14 of 16 mutation-confirmed OI type V patients.29

Preprocedural Chest Radiography

Preprocedural posteroanterior (PA) and lateral chest radiographs provide essential information about patient anatomy and help identify the location, type, and integrity of implanted lead and device hardware in patients with preexisting pacing and defibrillation systems.

Chest Wall Deformities

Chest wall deformities, such as kyphoscoliosis, result in hypoventilation that is caused by a decrease in chest wall compliance from the restriction of the chest wall due to the abnormal spinal curvature. The work of breathing, therefore, tends to be higher than normal. This eventually leads to muscle fatigue and alveolar hypoventilation.12 In addition, the deformity of the chest wall also likely contributes to suboptimal function of the diaphragm owing to its mechanical disadvantage. In fact, Lisboa and colleagues measured transdiaphragmatic pressures in nine patients with kyphoscoliosis and demonstrated a positive correlation with inspiratory muscle weakness and resulting ventilatory failure.13

Ultimately, the end result of reduced chest wall compliance and ineffectiveness of the diaphragm is diminished tidal volume that leads to a reduction in ventilation. Although alveolar dead space is unchanged, the ratio of dead space to tidal volume (Vd/Vt) is increased as a result of the decreased tidal volumes. Most patients with kyphoscoliosis are asymptomatic, except when the curvature of the spine is most severely deformed. It remains unclear whether or not the degree of spinal curvature or muscle strength is a better determinant of disease severity.14

24 What is pectus excavatum?

Pectus (chest) deformities occur as commonly as 1:300 live births. Pectus excavatum (funnel chest) is the most common chest wall deformity. The depression of the anterior chest wall usually begins at the sternal angle (angle of Louis) and reaches its deepest point at the level of the xiphoid. The concave deformity occasionally is so severe that the sternum contacts the vertebral bodies or passes to one side of the vertebral bodies into the paravertebral gutter, accounting for the associated cardiopulmonary and physiologic abnormalities. This anomaly is believed to result from overgrowth of the costal cartilages, which forces the sternum posteriorly in the case of pectus excavatum and anteriorly in the case of pectus carinatum (see Question 26).

Thoracic Deformities

Treatment of thoracic deformities is usually done to manage progression of deformity and/or cosmesis and sometimes pain. The techniques that are employed are similar to those used for adolescent scoliosis. In adults, however, thoracic curves are particularly stiff related to degenerative changes, not only in the discs but also in the facet joints. The effects of progressive fibrotic changes in chronically shortened muscles in the concavity of long-standing curvatures is unknown. Overcoming forces that are resistant to correction and then maintaining the correction to the point of successful fusion is the primary challenge to the adult deformity surgeon. Because of the inherent stiffness of the curves and the difficulty in obtaining and holding powerful corrections, the use of thoracoplasty to improve the cosmetic result for the patient is not uncommon. Stiff curves with significant hypokyphosis may benefit from an anterior release if pulmonary function is adequate; otherwise, the use of wide facetectomies and rod contouring to improve thoracic kyphosis is the technique preferred.

Multiple strategies currently exist for the specific application of hooks, sublaminar wires, or pedicle screws. In the older adult, the use of pedicle screws sometimes supplemented with a sublaminar wire or cable has diminished the problem of hook pullout or fracture of laminae in the upper thoracic spine. It is important, in an effort to prevent kyphosis proximal to the instrumentation, to generally carry the proximal instrumentation to T2. One of the complications in the upper thoracic spine of the older adult is the development of junctional kyphosis due to loss of the posterior tension band immediately proximal to the instrumentation (Fig. 20-8). The use of pedicle screws at the upper level has one further theoretical advantage that might help to prevent this complication. For pedicle screw insertion in the upper spine, there is no need to destroy the superiormost ligamentum flavum or the interspinous ligaments, which is often necessary with hooks, particularly when downward-going hooks are used at the top of a construct.

Rigid, severely rotated spines of 70 or more degrees, which are able to be corrected only minimally on side bending and which have been progressive, might require anterior releases prior to posterior segmental instrumentation. More recently, the use of multiple osteotomies in conjunction with thoracic screw fixation has decreased the need for anterior-posterior techniques.

B CLINICAL SIGNIFICANCE

Evidence linking the barrel chest deformity with chronic obstructive lung disease is conflicting. Two studies did find a significant correlation between the barrel chest deformity and more severe airflow obstruction,21,22 although another two studies found no relationship between the finding and measures of obstruction.18,23 Additional problems with this physical sign are that the barrel chest is not specific for obstruction and also occurs in elderly persons without lung disease18 and that, in some patients, the large anteroposterior dimension of the barrel chest is an illusion: The actual anteroposterior dimension is normal but it appears to be abnormally large because it contrasts with an abnormally thin abdominal dimension, caused by weight loss (Fig. 25-2).24

B Clinical Significance

Evidence linking the barrel chest deformity with chronic obstructive lung disease is conflicting. Two studies did find a significant correlation between the barrel chest deformity and more severe airflow obstruction,29,30 although another two studies found no relationship between the two conditions.28,31 Additional problems with this physical sign are that the barrel chest is not specific for obstruction but also occurs in elderly persons without lung disease.28 In some patients the large anteroposterior dimension of the barrel chest is an illusion; the actual anteroposterior dimension is normal but it appears to be abnormally large because it contrasts with an abnormally thin abdominal dimension caused by weight loss (Fig. 28.2).32

In a single study the presence of a barrel chest, defined either as clinician’s global impression of barrel chest or more precisely as a thoracic ratio greater than or equal to 0.9, modestly increased the probability of obstructive disease (LRs = 1.5 to 2.0, EBM Box 28.2).

Complications

The complications associated with thoracic deformity correction are related to the chosen surgical approach. Posterior, segmental pedicle screw fixation is the most common surgical approach to deformity correction in AS. This approach has been repeatedly demonstrated to be safe and biomechanically superior, with higher fusion rates and increased pullout resistance, to hook and wire constructs.91,100-102 Using proper technique, the incidence of spinal cord or nerve root injury, pneumothorax, and injury to the great vessels is negligible.92-95,103,104 The rate of pedicle screw revision is decreasing sharply since the introduction of the intraoperative O-arm

Neurophysiologic monitoring is another means by which to reduce the incidence of neurologic injury during deformity correction.105 One meta-analysis validated multimodal neuromonitoring as both a sensitive and specific tool whereby the surgeon may be alerted to neurologic injury.96 One study that reviewed more than two decades of deformity correction outcomes data, albeit in the pediatric AIS population, reported a less than 0.25% risk of postoperative neurologic deficit in patients with no change from baseline neurophysiologic monitoring during their operation.97

Pectus Excavatum

Abstract

Pectus excavatum is a congenital chest wall deformity characterized by a sternal depression, which typically begins at the manubrium and ends toward the xiphoid. At young age, the pectus excavatum causes no complaints, but as children become more active when they grow up, symptoms of shortness of breath on exertion, lack of endurance, and exercise tolerance appears. A frequent reason to seek medical attention is cosmetic concern. The most common surgical treatments are the Nuss procedure and the Ravitch procedure. Several modifications of the original operation exists. Compared with the Ravitch operation, the Nuss operation duration is much shorter and had lower blood loss. Length of hospital stay was similar. The overall anesthesia and surgery-related complication rate of the Nuss procedure is between 15% and 20%. A common complication is a small pneumothorax and pleural effusion. Chest tube drainage is not always necessary. Life-threatening complications are estimated to be 0.1%. The most devastating complication, cardiac perforation, is rather seldom. Anesthesiologists should be aware of this. Adequate pain therapy is essential to prevent discomfort and allow coughing, which is important to prevent pulmonary complications. Thoracic epidural is most frequently used as a primary analgesic modality. Compared with Ravitch, Nuss patients also had higher average daily pain scores and received more opioids, although both groups received an thoracic epidural. It is unique that a minimally invasive technique produces more pain. Many alternative pain therapies are possible. A hospital protocol should be established for optimal postoperative care.