Given the high cost of sealants and the results of this study, we advocate a critical attitude toward sealant application as an adjunct to classic dural closure.

Background Liqoseal consists of a watertight layer of poly(ester)ether urethane and an adhesive layer containing polyethylene glycol‐N‐hydroxysuccinimide (PEG‐NHS). It is designed to prevent cerebrospinal fluid (CSF) leakage after intradural surgery. This study assessed the safety and biodegradability of Liqoseal in a porcine craniotomy model. Methods In 32 pigs a craniotomy plus durotomy was performed. In 15 pigs Liqoseal was implanted, in 11 control pigs no sealant was implanted and in 6 control pigs a control dural sealant (Duraseal or Tachosil) was implanted. The safety of Liqoseal was evaluated by clinical, MRI and histological assessment. The degradation of Liqoseal was histologically estimated. Results Liqoseal, 2 mm thick before application, did not swell and significantly was at maximum mean thickness of 2.14 (±0.37) mm at one month. The foreign body reaction induced by Liqoseal, Duraseal and Tachosil were comparable. Liqoseal showed no adherence to the arachnoid layer and was completely resorbed between 6 and 12 months postoperatively. In one animal with Liqoseal, an epidural fluid collection containing CSF could not be excluded. Conclusion Liqoseal seems to be safe for intracranial use and is biodegradable. The safety and performance in humans needs to be further assessed in clinical trials.

Cerebrospinal fluid leakage is a frequent complication after cranial and spinal surgery. To prevent this complication and seal the dura watertight, we developed Liqoseal, a dural sealant patch comprising a watertight polyesterurethane layer and an adhesive layer consisting of poly(DL-lactide-co-ε-caprolactone) copolymer and multiarmed N-hydroxylsuccinimide functionalized polyethylene glycol. We compared acute burst pressure and resistance to physiological conditions for 72 h of Liqoseal, Adherus, Duraseal, Tachosil, and Tisseel using computer-assisted models and fresh porcine dura. The mean acute burst pressure of Liqoseal in the cranial model (145 ± 39 mmHg) was higher than that of Adherus (87 ± 47 mmHg), Duraseal (51 ± 42 mmHg) and Tachosil (71 ± 16 mmHg). Under physiological conditions, cranial model resistance test results showed that 2 of 3 Liqoseal sealants maintained dural attachment during 72 hours as opposed to 3 of 3 for Adherus and Duraseal and 0 of 3 for Tachosil. The mean burst pressure of Liqoseal in the spinal model (233 ± 81 mmHg) was higher than that of Tachosil (123 ± 63 mmHg) and Tisseel (23 ± 16 mmHg). Under physiological conditions, spinal model resistance test results showed that 2 of 3 Liqoseal sealants maintained dural attachment for 72 hours as opposed to 3 of 3 for Adherus and 0 of 3 for Duraseal and Tachosil. This novel study showed that Liqoseal is capable of achieving a strong watertight seal over a dural defect in ex vivo models.

BackgroundThe excimer laser-assisted non-occlusive anastomosis (ELANA) has been developed for intracranial bypass without the need for temporary recipient occlusion. We designed and tested a sutureless variant of the ELANA—the SELANA slide (SEsl).ObjectiveThis study aims to evaluate the SEsl preclinical results and describe its first clinical application.MethodsFirst, in a cadaver study, 28 SEsl anastomoses were compared with 28 ELANA anastomoses. Second, in an acute rabbit model, 90 SEsl anastomoses were compared with 30 ELANA anastomoses. Finally, in a surviving pig model, 38 SEsl bypasses were created. To evaluate the clinical efficacy of the SEsl, we then treated one patient with a giant, right-sided middle cerebral artery (MCA) aneurysm with an intracranial–intracranial SEsl bypass and parent vessel occlusion.ResultsIn preclinical studies, the SEsl anastomosis was shown to be equivalent or superior to the ELANA in terms of associated ease, patency, and bleeding complications. However, clinical application in rigid and arteriosclerotic receiving arteries was problematic. Although bypass creation and aneurysm occlusion were technically successful and the patient was postoperatively well, a pseudoaneurysm formed postoperatively at the internal carotid artery anastomosis and bled. Subsequent treatment failed and the patient did not survive.ConclusionThe SEsl showed promising preclinical results across three models. However, in its present form, it is not suitable for clinical application.Trial numberIRB UMCU 10/154.

Background A safe, effective, and ethically sound animal model is essential for preclinical research to investigate spinal medical devices. We report the initial failure of a porcine spinal survival model and a potential solution by fixating the spine. Methods Eleven female Dutch Landrace pigs underwent a spinal lumbar interlaminar decompression with durotomy and were randomized for implantation of a medical device or control group. Magnetic resonance imaging (MRI) was performed before termination. Results Neurological deficits were observed in 6 out of the first 8 animals. Three of these animals were terminated prematurely because they reached the predefined humane endpoint. Spinal cord compression and myelopathy was observed on postoperative MRI imaging. We hypothesized postoperative spinal instability with epidural hematoma, inherent to the biology of the model, and subsequent spinal cord injury as a potential cause. In the subsequent 3 animals, we fixated the spine with Lubra plates. All these animals recovered without neurological deficits. The extent of spinal cord compression on MRI was variable across animals and did not seem to correspond well with neurological outcome. Conclusion This study shows that in a porcine in vivo model of interlaminar decompression and durotomy, fixation of the spine after lumbar interlaminar decompression is feasible and may improve neurological outcomes. Additional research is necessary to evaluate this hypothesis.