Axonova Medical

Axonova Medical

https://axonovamed.com/

Functional restoration following major peripheral nerve injury (PNI) is challenging, given slow axon growth rates and eventual regenerative pathway degradation in the absence of axons. Smith et al. from the Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of MedicineAxonova Medical are developing tissue-engineered nerve grafts (TENGs) to simultaneously “bridge” missing nerve segments and “babysit” regenerative capacity by providing living axons to guide host axons and maintain the distal pathway. TENGs were biofabricated using porcine neurons and “stretch-grown” axon tracts. TENG neurons survived and elicited axon-facilitated axon regeneration to accelerate regrowth across both short (1 cm) and long (5 cm) segmental nerve defects in pigs. TENG axons also closely interacted with host Schwann cells to maintain pro-regenerative capacity. TENGs drove regeneration across 5-cm defects in both motor and mixed motor-sensory nerves, resulting in dense axon regeneration and electrophysiological recovery at levels similar to autograft repairs. This approach of accelerating axon regeneration while maintaining the pathway for long-distance regeneration may achieve recovery after currently unrepairable PNIs 1).


Burrell JC, Das S, Laimo FA, Katiyar KS, Browne KD, Shultz RB, Tien VJ, Vu PT, Petrov D, Ali ZS, Rosen JM, Cullen DK. Engineered neuronal microtissue provides exogenous axons for delayed nerve fusion and rapid neuromuscular recovery in rats. Bioact Mater. 2022 Mar 24;18:339-353. doi: 10.1016/j.bioactmat.2022.03.018. PMID: 35415305; PMCID: PMC8965778.


Wofford KL, Shultz RB, Burrell JC, Cullen DK. Neuroimmune interactions and immunoengineering strategies in peripheral nerve repair. Prog Neurobiol. 2022 Jan;208:102172. doi: 10.1016/j.pneurobio.2021.102172. Epub 2021 Sep 4. PMID: 34492307; PMCID: PMC8712351.


Shultz RB, Katiyar KS, Laimo FA, Burrell JC, Browne KD, Ali ZS, Cullen DK. Biopreservation of living tissue engineered nerve grafts. J Tissue Eng. 2021 Aug 11;12:20417314211032488. doi: 10.1177/20417314211032488. PMID: 34394908; PMCID: PMC8361542.


O’Donnell JC, Purvis EM, Helm KVT, Adewole DO, Zhang Q, Le AD, Cullen DK. An implantable human stem cell-derived tissue-engineered rostral migratory stream for directed neuronal replacement. Commun Biol. 2021 Jul 15;4(1):879. doi: 10.1038/s42003-021-02392-8. PMID: 34267315; PMCID: PMC8282659.


Katiyar KS, Burrell JC, Laimo FA, Browne KD, Bianchi JR, Walters A, Ayares DL, Smith DH, Ali ZS, Ledebur HC, Cullen DK. Biomanufacturing of Axon-Based Tissue Engineered Nerve Grafts Using Porcine GalSafe Neurons. Tissue Eng Part A. 2021 Oct;27(19-20):1305-1320. doi: 10.1089/ten.TEA.2020.0303. Epub 2021 Apr 9. PMID: 33514288; PMCID: PMC8610031.


1)

Smith DH, Burrell JC, Browne KD, Katiyar KS, Ezra MI, Dutton JL, Morand JP, Struzyna LA, Laimo FA, Chen HI, Wolf JA, Kaplan HM, Rosen JM, Ledebur HC, Zager EL, Ali ZS, Cullen DK. Tissue-engineered grafts exploit axon-facilitated axon regeneration and pathway protection to enable recovery after 5-cm nerve defects in pigs. Sci Adv. 2022 Nov 4;8(44):eabm3291. doi: 10.1126/sciadv.abm3291. Epub 2022 Nov 4. PMID: 36332027.

Vagus nerve stimulation complications

Vagus nerve stimulation complications

The most common side effects associated with Vagus nerve stimulation are hoarsenessthroat pain and coughingCardiac arrhythmia has been reported during lead tests performed during implantation of the device, but few cases during regular treatment.

After implanting vagus nerve electrodes to the cervical vagus nerve, side effects such as voice alterations and dyspnea or missing therapeutic effects are observed at different frequencies. Cervical vagus nerve branching might partly be responsible for these effects.

Adverse events (AEs) are generally associated with implantation or continuous on-off stimulation. Infection is the most serious implantation-associated AE. Bradycardia and asystole have also been described during implantation, as has vocal cord paresis, which can last up to 6 months and depends on surgical skill and experience. The most frequent stimulation-associated AEs include voice alteration, paresthesia, cough, headache, dyspnea, pharyngitis and pain, which may require a decrease in stimulation strength or intermittent or permanent device deactivation. Newer non-invasive VNS delivery systems do not require surgery and permit patient-administered stimulation on demand. These non-invasive VNS systems improve the safety and tolerability of VNS, making it more accessible and facilitating further investigations across a wider range of uses.

VNS battery replacement, revisions, and removals account for almost one-half of all VNS procedures. The findings suggest important long-term expectations for VNS including expected complications, battery life, and other surgical issues. Review of the literature suggests that the first large review of VNS revisions by a single center was done by Couch et al. The findings are important to better characterize long-term surgical expectations of VNS therapy. A significant portion of patients undergoing VNS therapy will eventually require revision 1).


In a retrospective study over an 8-year period, 13 patients underwent revision surgery due to lead failure. Lead failure was classified as either lead intrinsic damage or lead pin disengagement from the generator header. In the X-ray image, Zhou et al., defined an RC ratio that represented the portion of rear lead connector in the header receptacle. It was used to quantitatively evaluate the mechanical failure of the lead-header interface. Optimal procedures to identify and manage lead failure were established.

All 13 patients presented with high lead impedance ≥ 9 kOhms at the time of revision. Seven of ten patients with lead damage presented with increased seizure frequency after a period of seizure remission. In contrast to lead damages occurring relatively late (> 15 months), lead pin disengagement was usually found within the early months after device implantation. A significant association was found between an elevated RC ratio (≥ 35%) and lead pin disengagement. The microsurgical technique permitted the removal or replacement of the lead without adverse effects.

The method of measuring the RC ratio developed in this study is feasible for identifying lead disengagement at the generator level. Lead revision was an effective and safe procedure for patients experiencing lead failure 2).

Main risk of surgery is transient or permanent vocal cord paralysis.


Endotracheal Tube Electrode Neuromonitoring represents a safe adjunctive tool that can help localize the vagus nerve, particularly in the setting of varying anatomy or hazardous dissections. It may help reduce the potential for vagal trunk damage or electrode misplacement and potentially improve clinical outcomes 3).


1)

Couch JD, Gilman AM, Doyle WK. Long-term Expectations of Vagus Nerve Stimulation: A Look at Battery Replacement and Revision Surgery. Neurosurgery. 2016 Jan;78(1):42-6. doi: 10.1227/NEU.0000000000000985. PubMed PMID: 26678088.
2)

Zhou H, Liu Q, Zhao C, Ma J, Ye X, Xu J. Lead failure after vagus nerve stimulation implantation: X-ray examination and revision surgery. World Neurosurg. 2018 Dec 26. pii: S1878-8750(18)32893-6. doi: 10.1016/j.wneu.2018.12.070. [Epub ahead of print] PubMed PMID: 30593965.
3)

Katsevman GA, Josiah DT, LaNeve JE, Bhatia S. Endotracheal Tube Electrode Neuromonitoring for Placement of Vagal Nerve Stimulation for Epilepsy: Intraoperative Stimulation Thresholds. Neurodiagn J. 2022 Feb 28:1-12. doi: 10.1080/21646821.2022.2022911. Epub ahead of print. PMID: 35226831.

Woven EndoBridge (WEB)

Woven EndoBridge (WEB)

The Woven EndoBridge (WEB) (Sequent Medical, Aliso Viejo, California), is a ellipsoid braided-wire embolization device designed to provide flow disruption along the aneurysm neck 1).

Placed in the aneurysm, the device will modify the blood flow at the level of the neck and induce aneurysmal thrombosis. The WEB shape was designed to treat wide necked aneurysm. The device has been developed progressively from a dual-layer version (WEB DL) to single-layer versions (WEB SL and WEB SLS [single-layer spherical]).

This device does not require long-term antiplatelet use.

For the treatment of both ruptured and unruptured aneurysms. The WEB has received the CE mark and to date has been used to treat a wide variety of more than 1,400 aneurysms in Europe, Latin America and New Zealand. The WEB is not available for sale or use in the United States.

The WEB is a self-expanding, oblate, braided nitinol mesh.

The device is composed of an inner and outer braid held together by proximal, middle, and distal radiopaque markers, creating 2 compartments: 1 distal and 1 proximal. Depending on the device diame- ter, the inner and outer braids are 108 wires or 144 wires. Therefore, blood flow into a WEB-embolized aneurysm initially encounters 2 layers of wires comprising 216 or 288 wires, with the largest interwire distance ranging from 106 to 181 􏰅m, respectively, depending on the device size. The WEB implant is deployed—or retrieved before de- tachment—in a manner similar to that in endovascular coil systems, through microcatheters with an internal diameter 􏰆0.027 inch. For devices with a diameter of 􏰇7 mm, microcatheters with an internal diameter of 0.027 inch are used; and for devices with a diameter 􏰁7 mm, microcatheters with an internal diameter 0.032 inch are used. The detachment system is electrothermal and instantaneous. 2).


In a study, there was no difference in the early clinical course between those treated with WEB embolization, coil embolization, or neurosurgical clipping. Since WEB embolization is a valuable treatment alternative to coiling, it seems not justified to exclude this procedure from upcoming clinical SAH trials, yet the clinical long-term outcome, aneurysm occlusion, and retreatment rates have to be analyzed in further studies 3).

WEB Intrasaccular Therapy Study (WEB-IT)


The WEB Clinical Assessment of Intrasaccular Aneurysm Therapy (WEBCAST) trial is a prospective European trial evaluating the safety and efficacy of WEB in wide necked aneurysm of the bifurcation.

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It does not immediately secure the aneurysm in most subarachnoid hemorrhage cases. Second, it may not be suitable for embolization of wide-neck aneurysms with an unfavorable aspect ratio. To overcome these limitations, Zanaty et al., used the WEB device in conjunction with stenting and/or coiling.

They presented a technical note with an illustrated case-series, and provide a detailed step-by-step description on how the WEB device can be used in adjunct to coiling and/or stenting to achieve successful angiographic results. Accurate sizing of the WEB device before deployment is critical. Larger case-series are required to further assess the safety and success of these combined techniques 4).

Zhang et al. searched the PubMedOvid MEDLINE, and EMBASE databases between December 1, 2012 and June 30, 2018.

Studies that included five or more patients undergoing WEB for Wide necked intracranial aneurysms, reported an angiographic or clinical outcome and risk factors, and were published after December 1, 2012 were eligible.

Major outcomes included initial or short-term complete and adequate occlusion. Secondary outcomes included treatment failure, recanalizationmortalitymorbidity, and complication (e.g., thromboembolism or intraoperative rupture) rates. A random-effect model was used to pool the data. To assess risk factors for short-term angiographic outcomes and the most common complications, they conducted subgroup analyses and obtained odds ratios with 95% confidence intervals.

They included 36 studies (1759 patients with 1749 aneurysms). The initial complete and adequate occlusion rates were 35% and 77%, respectively. After a mean follow-up of 9.34 months, the short-term complete and adequate occlusion rates were 53% and 80%, respectively. Thromboembolism and recanalization were the most common complications (both 9%), followed by mortality (7%), morbidity (6%), failure (5%) and intraoperative rupture (3%). The following factors were related to higher short-term obliteration rates: unruptured status, in the anterior circulation, a medium neck (4-9.9 mm), newer-generation WEB and treatment without additional devices. Ruptured status, anterior circulation, preoperative antiplatelet therapy and newer-generation WEB were not significantly related to withto thromboembolism.

WEB has a satisfactory safety profile and shows promising efficacy in treating wide-neck intracranial aneurysms. They preliminarily identified several risk factors for short-term angiographic outcomes 5).

Woven EndoBridge case series.

A case of a shallow basilar tip aneurysm treated with the WEB device that required stabilization with Y-stent through radial access 6).


1)

Ding YH, Lewis DA, Kadirvel R, Dai D, Kallmes DF. The Woven EndoBridge: a new aneurysm occlusion device. AJNR Am J Neuroradiol. 2011 Mar;32(3):607-11. doi: 10.3174/ajnr.A2399. Epub 2011 Feb 17. PubMed PMID: 21330397.
2)

Pierot L, Liebig T, Sychra V, Kadziolka K, Dorn F, Strasilla C, Kabbasch C, Klisch J. Intrasaccular flow-disruption treatment of intracranial aneurysms: preliminary results of a multicenter clinical study. AJNR Am J Neuroradiol. 2012 Aug;33(7):1232-8. doi: 10.3174/ajnr.A3191. Epub 2012 Jun 7. PubMed PMID: 22678844.
3)

Sauvigny T, Nawka MT, Schweingruber N, Mader MM, Regelsberger J, Schmidt NO, Westphal M, Czorlich P. Early clinical course after aneurysmal subarachnoid hemorrhage: comparison of patients treated with Woven EndoBridge, microsurgical clipping, or endovascular coiling. Acta Neurochir (Wien). 2019 Jul 6. doi: 10.1007/s00701-019-03992-4. [Epub ahead of print] PubMed PMID: 31280480.
4)

Zanaty M, Roa JA, Dandapat S, Samaniego EA, Jabbour P, Hasan D. Diverse Use of the WEB Device: A Technical Note on WEB Stenting and WEB Coiling of Complex Aneurysms. World Neurosurg. 2019 Jul 10. pii: S1878-8750(19)31933-3. doi: 10.1016/j.wneu.2019.07.027. [Epub ahead of print] PubMed PMID: 31301439.
5)

Zhang SM, Liu LX, Ren PW, Xie XD, Miao J. Effectiveness, safety and risk factors of Woven EndoBridge device in the treatment of wide-neck intracranial aneurysms : systematic review and meta-analysis. World Neurosurg. 2019 Aug 13. pii: S1878-8750(19)32175-8. doi: 10.1016/j.wneu.2019.08.023. [Epub ahead of print] PubMed PMID: 31419591.
6)

Nordmann NJ, Weber MW, Dayoub H. Woven Endobridge (WEB) augmented by Y-stent in a shallow basilar tip aneurysm. J Cerebrovasc Endovasc Neurosurg. 2022 Feb 17. doi: 10.7461/jcen.2022.E2021.08.006. Epub ahead of print. PMID: 35172073.
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