Intrathoracic Prosthetic Implants |
| Pneumonectomy
remains one of the most physiologically consequential thoracic surgical
interventions, not only because of the immediate loss of pulmonary
parenchyma but also because of the anatomical reorganization that
follows in the weeks and months after surgery. Once the pleural space
is evacuated and the stump heals, the mediastinum—no longer
buttressed by the resected lung—begins a gradual shift toward the
empty hemithorax. In susceptible individuals, this displacement
progresses to the point of producing postpneumonectomy syndrome, a
condition defined by the compression of the residual airway and
mediastinal vascular structures as they are drawn into the operated
side. The resulting rotational deformity of the tracheobronchial tree
causes progressive obstructive ventilatory impairment, dyspnea on
exertion, recurrent pulmonary infections, and, in the most severe
cases, respiratory failure. Children and adolescents are
disproportionately affected due to the greater compliance of the
developing thoracic cage, which offers less resistance to mediastinal
migration, and the same syndrome can arise in patients with congenital
unilateral lung agenesis or severe hypoplasia even without prior
surgery. The pathophysiology of mediastinal displacement is not uniform across patients. While bronchial compression is the dominant mechanism in most cases, a distinct variant exists in which elevation of the ipsilateral hemidiaphragm is the primary driver of symptoms. In this presentation, the diaphragm ascends into the thoracic cavity and compresses the heart from below, producing a predominantly cardiogenic picture characterized by reduced stroke volume, near-syncope, exertional dyspnea, and hemodynamic instability that may initially be misattributed to primary cardiac disease if the surgical history is not carefully considered. Accurate diagnosis of postpneumonectomy syndrome requires cross-sectional imaging with multiplanar computed tomography reconstructions to quantify the degree of mediastinal rotation, delineate sites of airway or vascular compromise, and estimate the volume of the vacant hemithorax that will need to be occupied by a prosthetic implant. Flexible bronchoscopy provides complementary functional information by visualizing dynamic airway collapse during the respiratory cycle. Pulmonary function testing, when feasible, documents the obstructive or mixed ventilatory pattern and establishes a functional baseline against which postoperative recovery can be measured. Surgical correction through intrathoracic prosthetic implantation has become the standard of care for symptomatic patients who fail conservative management. The therapeutic rationale is straightforward: restoring volume to the empty hemithorax repositions the mediastinum toward the midline, relieves compression on the airway and great vessels, and reestablishes a more physiologically normal thoracic geometry. The operative approach involves a lateral thoracotomy with meticulous lysis of pleural adhesions that have formed since the original pneumonectomy, followed by pericardiopexy—a suture fixation of the pericardium to the mediastinal pleura that anchors the heart in a more anatomical position and substantially reduces the risk of postoperative cardiac herniation or dislocation. After achieving adequate exposure and mobilization within the hemithorax, the implant is introduced and filled incrementally under continuous hemodynamic monitoring. Central venous pressure serves as the primary guide for intraoperative filling: an increase of more than five millimeters of mercury above baseline, or an absolute value exceeding ten millimeters of mercury, signals that further volume addition risks venous compression and hemodynamic collapse and that filling should be suspended. The selection of implant type is among the most clinically significant decisions in procedural planning and has evolved considerably since the technique was first described. Tissue expanders fabricated from silicone with a percutaneously accessible injection port have emerged as the preferred option in pediatric patients for a mechanistically important reason: they allow incremental volume adjustments as the child grows without requiring additional surgery. Because the thoracic cage continues to develop for years into adolescence, the volume that optimally repositions the mediastinum at the time of implantation may become insufficient as the chest expands, and the ability to add saline through the port on an outpatient basis makes the tissue expander a dynamic, adaptable device uniquely suited to this population. Fixed-volume implants—whether saline-filled or silicone gel—offer the clinical advantage of a definitive single-stage implant requiring no subsequent manipulation, a consideration that favors their use in adult patients whose thoracic growth has ceased and in whom volumetric predictability is more reliably achievable. The body of evidence regarding clinical outcomes of intrathoracic prosthetic implantation demonstrates rates of symptomatic improvement exceeding eighty percent across reported series, with complete resolution of the syndrome achieved in approximately two-thirds of cases. Comparative analyses between implant types have not demonstrated statistically significant differences in clinical efficacy, which effectively positions implant selection as a decision based on patient-specific factors, institutional experience, and logistical considerations rather than on differential therapeutic benefit. The pediatric surgical context introduces additional complexity, as many children present with dense adhesions from prior interventions, significant anatomical distortion, and greater intraoperative hemodynamic lability—all of which demand meticulous surgical planning and an anesthesia team with specific expertise in complex pediatric thoracic procedures. The complication profile associated with intrathoracic implants warrants careful attention and informs both implant selection and postoperative surveillance strategies. Content leakage, reported in approximately twelve percent of cases, affects exclusively saline-filled devices and typically manifests as gradual symptomatic recurrence without systemic consequences, since the saline is reabsorbed by surrounding tissues. Management involves implant replacement or conversion to a silicone device. Overfilling symptoms—dyspnea, thoracic discomfort, and restriction of contralateral lung expansion—occur more commonly with fixed-volume implants that cannot be partially deflated after placement, and their resolution requires either partial aspiration where the device permits or implant exchange. Device infection, though infrequent, constitutes a serious complication that may necessitate removal of the implant and prolonged antimicrobial therapy. A distinct clinical entity associated specifically with silicone gel implants, termed silicone incompatibility syndrome, presents with recurrent fevers, arthralgias, night sweats, and fatigue—a systemic inflammatory response to the prosthetic material. This diagnosis, reached by exclusion, resolves completely following removal, confirming its reactive rather than infectious nature. A consistent finding across studies is the volumetric relationship between implant size and complication rate: patients who experience complications have mean implant volumes significantly greater than those who do not, suggesting that oversizing the prosthesis represents an independent modifiable risk factor and that conservative volumetric planning is preferable to aggressive filling. From an anesthesiologic standpoint, intrathoracic implant surgery presents challenges that distinguish it from other thoracic procedures and demand a tailored perioperative approach. Patients with significant mediastinal displacement are highly preload-dependent, and the transition to positive-pressure mechanical ventilation at induction can precipitate cardiovascular collapse if adequate intravascular volume has not been established beforehand. Anesthetic agents with minimal cardiovascular depression are preferred, and vasopressors must be immediately available throughout the induction sequence. Lung isolation using a double-lumen endotracheal tube optimizes the operative field and protects the functioning lung from contamination, but placement may be technically demanding in patients with distorted airway anatomy and often requires bronchoscopic guidance for confirmation of position. Ventilatory strategy for the single remaining lung must prioritize protection: reduced tidal volumes, plateau pressure limitation, and individualized positive end-expiratory pressure titration minimize the risk of ventilator-induced injury to the parenchyma on which the patient's entire gas exchange depends. The real-time central venous pressure monitoring during the intraoperative filling phase integrates seamlessly into this anesthetic framework, providing an objective and continuously updated hemodynamic endpoint that allows the surgical team to maximize implant volume without incurring acute circulatory compromise. The totality of available evidence supports intrathoracic prosthetic implantation as an effective and acceptably safe intervention for postpneumonectomy syndrome across its clinical variants, from classic bronchial compression to the less common cardiac compression phenotype. Long-term follow-up confirms the durability of functional benefit and the feasibility of volume adjustment in response to clinical changes or somatic growth. Structured periodic surveillance incorporating clinical assessment and cross-sectional imaging is essential for early detection of late complications, particularly the silent rupture of silicone gel implants, whose absence of acute clinical manifestations can result in delayed diagnosis and prolonged exposure to intrathoracic silicone extravasation. Ultimately, optimal outcomes depend on the integration of appropriate implant selection tailored to patient characteristics, precise surgical execution with continuous hemodynamic monitoring, anesthetic management aligned to the specific pathophysiology of each case, and a structured long-term follow-up protocol that sustains the functional gains achieved at surgery. References: 1- Gardner L, Franklin A, Menser C: Anesthetic Care of a Child With Congenital Pulmonary Agenesis and Indwelling Intrathoracic Tissue Expander Undergoing Posterior Spinal Fusion. J Cardiothorac Vasc Anesth. 31(5):e70-e71, 2017 2- Merlo A, McDermott C, Wilson H, Haithcock B: Inflammatory State After Intrathoracic Breast Implant Placement for Postpneumonectomy Syndrome. Ann Thorac Surg. 110(4):e275-e277, 2020 3- Quong WL, Bulstrode N, Beeman A, Ramaswamy M, Sivakumar B, Wallis C, Elliott MJ, Muthialu N: Intrathoracic prosthesis in children in preventing post pneumonectomy syndrome: Its role in congenital single lung and post pneumonectomy situations. J Pediatr Surg. 57(4):581-585, 2022 4- Holmes K, Agko M, Kuckelman J, Miller D: Cardiac Postpneumonectomy Syndrome. Ann Thorac Surg Short Rep. 3(4):886-888, 2025 5- Hancock M, Skochdopole AJ, Trevino M, Orozco-Sevilla V, Ripley RT, Winocour SJ: Intrathoracic breast implants for postpneumonectomy syndrome: A systematic review of safety and efficacy. J Plast Reconstr Aesthet Surg. 115:33-46, 2026 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|