The “Spacemaker”: a novel scopic approach facilitating minimally invasive cardiothoracic surgery
Paul F. Grundeman, MD, PhD1, Pieter W. J. Lozekoot, MD2, Gerard Pasterkamp, MD, PhD1, Jos G. Maessen, MD, PhD2, Paul B. Kwant, PhD2.
1Utrecht University Medical Center, The Netherlands, Utrecht, Netherlands, 2Maastricht University Medical Center, The Netherlands, Maastricht, Netherlands.
OBJECTIVE: Minimally invasive cardiothoracic surgical approaches, like keyhole ablation surgery and left atrial appendix exclusion, currently require CO2-overpressure insufflation and/or alternate left/right sided single lung ventilation. These techniques create an oversized surgical corridor which may coincide with a firm drop in blood pressure, depressed cardiac output, over-infusion, shunting, loss of arterial oxygen saturation and prolonged ventilation time which is not well tolerated in the aging frail patient with compromised heart and lung function. We invented an inflatable lung retractor called “Spacemaker” that circumvents homeostatic downsides of traditional space creating methods, and also excludes the use of a double lumen ventilation tube.
METHODS: The retractor was tested in >5 anesthetized pigs (85-100 kg) placed on standard endotracheal ventilation. The “Spacemaker” is constructed out of two sealed sheets of poly-urethane. Packed in deflated condition, the retractor was introduced into the right or the left chest, upon choice of intervention, via an incision of 3x2cm in the fifth intercostal space and positioned anteriorly of the lung lobes prior to expansion. Two additional 10 mm trocar-ports were placed in the fourth and seventh posterior axillar line, respectively, to be used as instrumental ports.
RESULTS: Introduction was easy and unhindered. Under thoracoscopic vision, the "Spacemaker" was inflated up to 0,5 bar thereby pushing the lung tissue gently away cranially, posteriorly and caudally without interfering with diastolic filling of the heart. Blood pressure, cardiac output and oxygen saturation did not change. The “Spacemaker” created an ovally shaped tunnel sizing roughly 5 x 10 cm allowing unhindered feeding and maneuvering of instruments. Different closed chest surgical procedures such as left atrial appendage exclusion, pulmonary vein exposure, pacemaker lead placement and endoscopic stabilization for coronary surgery, were successfully performed in stable hemodynamic and respiratory conditions without damaging tissue or bleedings. Removal was quick and complete in all cases and lung tissue showed no remnant atelectasis.
CONCLUSIONS: In the normally ventilated pig, the "Spacemaker" created succesfully a surgical corridor for keyhole surgical procedures to the heart, lung and blood vessels without hemodynamic and respiratory compromise. Currently, the “Spacemaker” is prepared for first use in humans.
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