Static and dynamic periosteal elevation: a pilot study in a pig model.

The osteoinductive potential of periosteum and bone can be stimulated by elevating the periosteum in a distraction-like modus, but also by an ad-hoc elevation. This was tested and proved in an experiment in 9 Goettingen mini-pigs with elevation heights of 5, 10 and 15mm. Specially designed and perforated titanium meshes were implanted subperiosteally to compare the dynamic elevation procedure with static shielding. The cumulative results for bone formation underneath the mesh were 66% in dynamic and 67% in non-dynamic elevation. The cumulative results for mineralization of the bone regenerates in comparison with the underlying basal bone of the skull showed independently from the technique applied no difference bigger than 5%. No major difference in bone formation could be observed in this pilot study. The main advantages of dynamic periosteal elevation and static shielding are minimal invasion and morbidity. Periosteal elevation could be applied in cranio-maxillofacial surgery, in preimplantological augmentation and in reconstructive surgery of the skull; applications in other specialties may be possible.

Minimally invasive neck surgery. Surgical feasibility and physiological effects of carbon dioxide insufflation in a unilateral subplatysmal approach.

Endoscopically assisted, minimally invasive techniques to regions without a natural cavity require insufflation with carbon dioxide (CO2). In the neck region this may impair hemodynamics, blood gas homoeostasis, cerebral blood circulation and increase the intracranial pressure. An exclusively endoscopic unilateral subplatysmal approach to the submandibular region was investigated in nine mini-pigs randomized to three groups. On both neck sides, within a 14 day interval, the subplatysmal space was inflated with CO2 at 10 mmHg, 20 mmHg (1.33/2.66 x 10 (3)Pa) or 20 mmHg (2.66 x 10 (3)Pa) combined with mechanical suspension. Data for hemodynamic and blood gas parameters, gas volumes, and intracranial pressure were obtained preoperatively, 30 min after onset and 10 min postopeatively. In a pocket created by insufflation of 20 mmHg (2.66 x 10 (3)Pa), exposition and resection of the submandibular gland were accomplished easily. The elevation procedure had technical disadvantages. The mean operation time was 48.9 min. Unilateral subplatysmal carbon dioxide insufflation of the submandibular neck region up to 20 mmHg (2.66 x 10 (3)Pa) did not affect physiological parameters. As an exclusive endoscopical approach for unilateral surgery of the submandibular region, the use of inflation pressures of up to 20 mmHg (2.66 x 10 (3)Pa) might be considered.