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1. Daily oscillations of neuronal membrane capacitance

Author

Daniel Severin, Cristián Moreno, Trinh Tran, Christian Wesselborg, Sofia Shirley, Altagracia Contreras, Alfredo Kirkwood, and Jorge Golowasch

Subjects
CP: Neuroscience, Biology (General), QH301-705.5
Abstract

Summary: Capacitance of biological membranes is determined by the properties of the lipid portion of the membrane as well as the morphological features of a cell. In neurons, membrane capacitance is a determining factor of synaptic integration, action potential propagation speed, and firing frequency due to its direct effect on the membrane time constant. Besides slow changes associated with increased morphological complexity during postnatal maturation, neuronal membrane capacitance is considered a stable, non-regulated, and constant magnitude. Here we report that, in two excitatory neuronal cell types, pyramidal cells of the mouse primary visual cortex and granule cells of the hippocampus, the membrane capacitance significantly changes between the start and the end of a daily light-dark cycle. The changes are large, nearly 2-fold in magnitude in pyramidal cells, but are not observed in cortical parvalbumin-expressing inhibitory interneurons. Consistent with daily capacitance fluctuations, the time window for synaptic integration also changes in pyramidal cells.

Published
2024
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3. Dipolar spin-waves and tunable band gap at the Dirac points in the 2D magnet ErBr3

Author

Christian Wessler, Bertrand Roessli, Karl W. Krämer, Uwe Stuhr, Andrew Wildes, Hans B. Braun, and Michel Kenzelmann

Subjects
Astrophysics, QB460-466, Physics, QC1-999
Abstract

Magnonic devices, based on the physics of spin-waves, are a potential alternative to process and store information that consume less energy and van der Waals crystals are candidate materials for such applications. Here, the authors investigate the magnetic ground state and spin-wave spectrum of ErBr3 finding that the dipolar interactions play a dominant role and allow for continuous control of topological excitations.

Published
2022
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4. Bioabsorbable instrumentation for single-level cervical degenerative disc disease: a radiological and clinical outcome study

Author

Christian Wess, Andre Tomasino, Harry Gebhard, Karishma Parikh, and Roger Härtl

Subjects
medicine.medical_specialty, business.industry, medicine.medical_treatment, Kyphosis, Anterior cervical discectomy and fusion, General Medicine, medicine.disease, Degenerative disc disease, Surgery, Intervertebral disk, Myelopathy, Radiological weapon, Discectomy, Cervical spondylosis, Medicine, business
Abstract

Object The authors present the radiological and clinical outcome data obtained in patients who underwent single-level anterior cervical discectomy and fusion (ACDF) for cervical spondylosis and/or disc herniation; bioabsorbable plates were used for instrumentation. The use of metallic plates in ACDF has gained acceptance as a stabilizing part of the procedure to increase fusion rates, but when complications occur with these devices, the overall effectiveness of the procedure is compromised. As a possible solution, bioabsorbable implants for ACDF have been developed. This study investigates the feasibility and radiological and clinical outcomes of the bioabsorbable plates for ACDF. Methods The radiological and clinical outcomes of 30 patients were investigated retrospectively. All patients presented with cervical radiculopathy or myelopathy and underwent single-level ACDF in which a bioabsorbable anterior cervical plate and an allograft bone spacer were placed at a level between C-3 and C-7. Radiological outcome was assessed based on the fusion rate, subsidence, and Cobb angle of the surgical level. Clinical outcome was determined by using a visual analog scale, the Neck Disability Index, and the Odom criteria. Results There were no intraoperative complications, and no hardware failure was observed. No signs or symptoms of adverse tissue reaction caused by the implant were seen. Two reoperations were necessary due to postoperative blood collections. The overall complication rate was 16.7%. After 6 months, radiographic fusion was seen in 92.3% of patients. Subsidence at 11.3 ± 7.2 months was 3.1 ± 5.8 mm (an 8.2% change over the immediately postoperative results), and the change in the sagittal curvature was –2.7 ± 2.7°. The visual analog scale score for neck and arm pain and Neck Disability Index improved significantly after surgery (p < 0.001). Overall at 19.5 months postoperatively, 83% of the patients had favorable outcomes based on the Odom criteria. Conclusions Absorbable instrumentation provides better stability than the absence of a plate but graft subsidence and deformity rates may be higher than those associated with metal implants. There were no device-related complications, but adverse late effects cannot be excluded. The fusion rate and outcome are comparable to the results achieved with metallic plates. The authors were satisfied with the use of bioabsorbable plates as a reasonable alternative to metal, avoiding the need for lifelong metallic implants.

Published
2009
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5. Trigeminal and occipital peripheral nerve stimulation for craniofacial pain: a single-institution experience and review of the literature

Author

Naureen Munawar, Christian Wess, Colpan Me, Hrachya Nersesyan, and Konstantin V. Slavin

Subjects
Adult, Male, medicine.medical_specialty, Migraine Disorders, Peripheral nerve stimulation, Neuralgia, Postherpetic, Electric Stimulation Therapy, Facial Pain, Recurrence, medicine, Humans, Peripheral Nerves, Prospective Studies, Trigeminal Nerve, Craniofacial, Prospective cohort study, Device Removal, Aged, Aged, 80 and over, Trigeminal nerve, business.industry, Patient Selection, General Medicine, Middle Aged, medicine.disease, Neuromodulation (medicine), Electrodes, Implanted, Surgery, Treatment Outcome, Anesthesia, Neuropathic pain, Neuralgia, Female, Occipital nerve stimulation, Neurology (clinical), Analgesia, business, Follow-Up Studies
Abstract

Object Treatment of chronic neuropathic pain in the region of the head and face presents a challenge for pain specialists; patients who do not respond to conventional treatment modalities usually continue to suffer from pain due to the lack of reliable medical and surgical approaches. Peripheral nerve stimulation (PNS) has been used to treat neuropathic pain for many decades, but only recently has it been applied systematically to the craniofacial region. To advance the study of this treatment option, the authors present their initial experience with this approach, summarize published data on the use of PNS in treatment of craniofacial pain, and discuss some technical details of the craniofacial PNS procedure. Methods A review of prospectively collected data in 30 patients who underwent PNS surgery for craniofacial pain was performed. The pain location, duration, cause, and previous treatments were analyzed, along with the surgical details, initial and long-term results, complications, and repeated operations. Stimulated nerves in this group included supraorbital (seven patients), infraorbital (six), and occipital (21); in 19 patients more than one nerve was stimulated. Twenty-two patients proceeded with implantation of a permanent system after the trial. Of these, at the time of the latest evaluation (mean follow-up duration 35 months), in two patients the devices had been removed because of pain improvement over time, in three the devices were removed due to loss of effectiveness (two cases) or late infection (one), and the rest are enjoying either complete (15 patients) or partial (two patients) pain relief. Three patients underwent repeated operation due to lead erosion, infection, or migration. Conclusions Peripheral nerve stimulation appears to be a safe and effective approach in the treatment of craniofacial neuropathic pain. The growing body of literature supports a wider acceptance of this approach in the field of pain surgery.

Published
2006
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6. Trigeminal Branch Stimulation for Intractable Neuropathic Pain: Technical Note

Author

Konstantin V. Slavin and Christian Wess

Subjects
Trigeminal nerve, medicine.medical_specialty, business.industry, Stimulation, Technical note, General Medicine, Neuromodulation (medicine), Peripheral, Surgery, Peripheral nerve field, Anesthesiology and Pain Medicine, Neurology, Anesthesia, Neuropathic pain, Medicine, Intractable pain, Neurology (clinical), business
Abstract

Intractable neuropathic facial pain resulting from injury to the peripheral branches of the trigeminal nerve presents a significant challenge for neurologists, pain specialists, and neurosurgeons. In this paper, we describe our technique of peripheral nerve stimulation of the infraorbital and supraorbital nerves to treat patients with medically intractable facial pain. Stimulation of the infraorbital and supraorbital nerves is performed using percutaneously inserted electrodes that are positioned in the epifascial plane, traversing the course of the infraorbital or supraorbital nerves. The temporary electrodes are inserted under fluoroscopic guidance and are anchored to the skin. A trial lasting a few days is followed, if successful, by insertion of a permanent electrode that is tunneled under the skin behind the ear toward the infraclavicular pocket, which houses the implantable pulse generator. Our technique of electrode insertion to stimulate the infraorbital or supraorbital nerves has been successfully used in several patients with neuropathic trigeminal pain of various etiologies. In patients who underwent permanent electrode implantation, stimulation resulted in long lasting pain relief; complications were rare and minor. We conclude that trigeminal branch stimulation is a simple technique that can be used in selected patients with neuropathic pain in the distribution of the infraorbital or supraorbital nerves. This procedure may provide relief of medically intractable pain, without the need for destructive procedures or more central modulation approaches.

Published
2005
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8. Contributors

Author

Bizhan Aarabi, Rick Abbott, Saleem I. Abdulrauf, Frank L. Acosta, John R. Adler, Nzhde Agazaryan, Manish Aghi, Edward S. Ahn, Ali Alaraj, Gregory W. Albert, Leland Albright, Felipe C. Albuquerque, Tord D. Alden, Michael J. Alexander, Andrei V. Alexandrov, Ossama Al-Mefty, Ron L. Alterman, Lázaro Álvarez, Nduka M. Amankulor, Peter S. Amenta, Christopher P. Ames, Sepideh Amin-Hanjani, Mario Ammirati, Carryn Anderson, Richard C.E. Anderson, William S. Anderson, Peter D. Angevine, Hiba Arif, Jeffrey E. Arle, Rocco Armonda, Paul M. Arnold, Kaveh Asadi-Moghaddam, Ferhan A. Asghar, William W. Ashley, Sabri Aydin, Nafi Aygun, Joachim M. Baehring, Jacob H. Bagley, Diaa Bahgat, Julian E. Bailes, Jonathon R. Ball, Gordon H. Baltuch, Nicholas C. Bambakidis, Scott C. Baraban, Igor J. Barani, Nicholas M. Barbaro, Frederick G. Barker, Gene H. Barnett, Stanley L. Barnwell, Constance M. Barone, Daniel L. Barrow, Fabrice Bartolomei, Juan Bartolomei, Tracy T. Batchelor, H. Hunt Batjer, Andrew M. Bauer, Joel A. Bauman, Thomas K. Baumann, James E. Baumgartner, John Bayouth, Andrew Beaumont, Joshua B. Bederson, Rudolf Beisse, Randy S. Bell, Allan Belzberg, Alim Louis Benabid, Eduardo E. Benarroch, Abdelhamid Benazzouz, Bernard R. Bendok, Edward C. Benzel, Alejandro Berenstein, Mitchel S. Berger, Marvin Bergsneider, Helmut Bertalanffy, Tarun Bhalla, Dani S. Bidros, José Biller, Mark H. Bilsky, Devin K. Binder, William Bingaman, Rolfe Birch, Allen T. Bishop, Peter M. Black, Jeffrey P. Blount, Peter C. Blumbergs, Leif-Erik Bohman, Zackary E. Boomsaad, Frederick A. Boop, Pascal Bou-Haidar, Daniel R. Boué, Blaise F.D. Bourgeois, Robin M. Bowman, Oliver Bozinov, Helen M. Bramlett, Henry Brem, Steven Brem, Gavin W. Britz, Douglas L. Brockmeyer, David J. Brooks, Samuel R. Browd, Paul D. Brown, Robert D. Brown, Jeffrey N. Bruce, Janice E. Brunstrom-Hernandez, John Buatti, M. Ross Bullock, Kim J. Burchiel, Peter C. Burger, Marc R. Bussière, Mohamad Bydon, Richard W. Byrne, Maria Elisa Calcagnotto, Victoria A. Campbell, William Campbell, George M. Cannon, Louis P. Caragine, Benjamin S. Carson, Gregory D. Cascino, Ethan Cascio, Frédéric Castinetti, C. Michael Cawley, Justin S. Cetas, Stéphan Chabardès, Edward F. Chang, Eric C. Chang, Eric L. Chang, Steven D. Chang, Steven W. Chang, Susan M. Chang, Kevin Chao, Paul H. Chapman, Fady T. Charbel, Patrick Chauvel, Grace Chen, Boyle C. Cheng, Joseph S. Cheng, Joshua J. Chern, E. Antonio Chiocca, Ondrej Choutka, Shakeel A. Chowdhry, Cindy W. Christian, Kathy Chuang, Jan Claassen, Richard E. Clatterbuck, Elizabeth B. Claus, Daniel R. Cleary, Robert J. Coffey, Alan R. Cohen, Andrew J. Cole, E. Sander Connolly, Patrick J. Connolly, Anne G. Copay, Jeroen R. Coppens, James J. Corbett, Daniel M. Corcos, Domagoj Coric, Garth Rees Cosgrove, William T. Couldwell, Stirling Craig, Neil R. Crawford, Peter B. Crino, R. Webster Crowley, Bradford A. Curt, Marek Czosnyka, Zofia Czosnyka, Vladimir Y. Dadashev, Andrew T. Dailey, Deepa Danan, Shabbar F. Danish, Shervin R. Dashti, Carlos A. David, David J. David, Arthur L. Day, Antonio A.F. De Salles, Amir R. Dehdashti, Oscar H. Del Brutto, Johnny B. Delashaw, Bradley Delman, Mahlon R. DeLong, Franco DeMonte, Sanjay S. Dhall, Mark S. Dias, Curtis A. Dickman, W. Dalton Dietrich, Michael L. DiLuna, Francesco Di Meco, Peter Dirks, C. Edward Dixon, Jacob A. Donoghue, Ian G. Dorward, Amish H. Doshi, James Drake, Dan Drzymalski, Rose Du, Andrew Ducruet, Ann-Christine Duhaime, Aaron S. Dumont, Christopher D. Duntsch, Joshua R. Dusick, Suzan Dyve, James Eberwine, Paula Eboli, Robert D. Ecker, Richard J. Edwards, Marc E. Eichler, Doortje C. Engel, Nancy E. Epstein, Matthew G. Ewend, Hamad Farhat, Christopher J. Farrell, Michael G. Fehlings, Iman Feiz-Erfan, Neil A. Feldstein, Richard G. Fessler, Juan J. Figueroa, Aaron G. Filler, J. Max Findlay, Michael A. Finn, David J. Fiorella, James L. Fisher, Robert S. Fisher, Eugene S. Flamm, James D. Fleck, Kelly D. Flemming, John C. Flickinger, Laura Flores-Sarnat, Kenneth A. Follett, Kelly D. Foote, Daryl R. Fourney, Valerie Fraix, James L. Frazier, Itzhak Fried, Allan H. Friedman, William A. Friedman, Gerhard M. Friehs, Donald E. Fry, Gregory N. Fuller, Hector H. Garcia, Paul A. Gardner, Mark Garrett, Hugh Garton, Cormac G. Gavin, Alisa D. Gean, Thomas A. Gennarelli, Venelin Gerganov, Anand V. Germanwala, Massimo Gerosa, Elizabeth R. Gerstner, Peter C. Gerszten, Saadi Ghatan, Samer Ghostine, Steven Giannotta, Paul R. Gigante, Frank Gilliam, Holly Gilmer-Hill, Albert Gjedde, Roberta P. Glick, Ziya L. Gokaslan, Yakov Gologorsky, Kiarash Golshani, Nestor R. Gonzalez, James Tait Goodrich, Tessa Gordon, Alessandra A. Gorgulho, Liliana C. Goumnerova, M. Sean Grady, Jordan Grafman, Sylvie Grand, Gerald A. Grant, Gregory P. Graziano, Benjamin Greenberg, James Guest, Abhijit Guha, Murat Günel, Gaurav Gupta, Nalin Gupta, Jorge Guridi, Barton L. Guthrie, Georges F. Haddad, Michael M. Haglund, Regis W. Haid, Stephen J. Haines, Clement Hamani, Bronwyn E. Hamilton, D. Kojo Hamilton, Todd C. Hankinson, Leo T. Happel, Ihtsham Ul Haq, Raqeeb Haque, Robert E. Harbaugh, Ciara D. Harraher, Leo Harris, James S. Harrop, Wael Hassaneen, Cynthia Hawkins, Gregory W.J. Hawryluk, Neal G. Haynes, Robert F. Heary, Amy B. Heimberger, Mary M. Heinricher, Thomas M. Hemmen, Jaimie M. Henderson, Roberto C. Heros, Karl Herrup, Shawn L. Hervey-Jumper, Gregory G. Heuer, Lawrence J. Hirsch, Robert Hirschl, Brian L. Hoh, Daniel J. Hoh, Eric C. Holland, Paul E. Holtzheimer, L. Nelson Hopkins, Philip J. Horner, David A. Hovda, Matthew A. Howard, Patrick Hsieh, Yin C. Hu, Sherwin E. Hua, Jason H. Huang, Judy Huang, Samuel A. Hughes, Thierry A.G.M. Huisman, Matthew A. Hunt, R. John Hurlbert, Robert W. Hurst, Anita Huttner, Steven W. Hwang, Ioannis U. Isaias, Bermans J. Iskandar, Arun Jacob, Kurt A. Jaeckle, Jay Jagannathan, Regina I. Jakacki, George I. Jallo, John A. Jane, Ryan Janicki, Damir Janigro, N u Owase Jeelani, Kurt A. Jellinger, Arthur L. Jenkins, Sarah Jernigan, David F. Jimenez, Conrad E. Johanson, J. Patrick Johnson, Matthew D. Johnson, G. Alexander Jones, Rajni K. Jutla, Koijan Singh Kainth, Michael G. Kaiser, U. Kumar Kakarla, Iain H. Kalfas, Aleksandrs Uldis Kalnins, Hideyuki Kano, Yucel Kanpolat, Adam S. Kanter, Reza J. Karimi, Amin B. Kassam, Bruce A. Kaufman, Christian B. Kaufman, Hiroto Kawasaki, Brian C. Kelley, Christopher P. Kellner, Nicole C. Keong, John R.W. Kestle, Alexander A. Khalessi, Nadia Khan, Vini G. Khurana, Daniel H. Kim, Dong Gyu Kim, Dong H. Kim, Jong Hyun Kim, Louis J. Kim, Paul K. Kim, Thomas Aquinas Kim, Won Kim, James A.J. King, Ryan S. Kitagawa, Neil D. Kitchen, Paul Klimo, David G. Kline, Kazutaka Kobayashi, Patrick M. Kochanek, Douglas Kondziolka, Paul N. Kongkham, Tyler R. Koski, Thomas Kosztowski, Paul Krack, Joachim K. Krauss, Michael A. Kraut, Niklaus Krayenbühl, Thomas Kretschmer, Ajit Krishnaney, Charles Kuntz, Jeffrey V. Kuo, Brian K. Kwon, Nadia N. Issa Laack, Shivanand P. Lad, Alim M. Ladha, Amos K. Ladouceur, Arthur M. Lam, Frederick F. Lang, Giuseppe Lanzino, Sean D. Lavine, Edward R. Laws, Michael T. Lawton, Adrian W. Laxton, Tuong H. Le, Jean François LeBas, Brett D. Lebed, Richard L. Lebow, Amy Lee, Ian Lee, Seon-Kyu Lee, Emily Lehmann, James W. Leiphart, Gregory P. Lekovic, Frederick A. Lenz, Jeffrey R. Leonard, Peter D. LeRoux, Marc Lévêque, Allan D. Levi, Elad I. Levy, Linda M. Liau, Jason Liauw, Roger Lichtenbaum, Terry Lichtor, David D. Limbrick, Hester Lingsma, Michael J. Link, Mark E. Linskey, Brian Litt, Zachary N. Litvack, James K.C. Liu, Kenneth C. Liu, Jay S. Loeffler, Christopher M. Loftus, Russell R. Lonser, Angeliki Louvi, Andres M. Lozano, Daniel C. Lu, Rimas V. Lukas, L. Dade Lunsford, Neal Luther, Pedro Lylyk, Andrew I.R. Maas, R. Loch Macdonald, Andre Machado, Raul Macias, Robert J. Maciunas, Brian N. Maddux, Pierre Magistretti, Martijn J.A. Malessy, Neil R. Malhotra, Donald A. Malone, Adam N. Mamelak, Christopher E. Mandigo, Francesco T. Mangano, Allen H. Maniker, Geoffrey T. Manley, Daniel Marchac, Anthony Marmarou, Joseph C. Maroon, Lawrence F. Marshall, Neil A. Martin, Timothy J. Martin, Alexander M. Mason, Marlon S. Mathews, Helen S. Mayberg, James P. McAllister, J. Gordon McComb, Paul C. McCormick, Ian E. McCutcheon, Michael W. McDermott, Cameron G. McDougall, Matthew McGehee, Cameron C. McIntyre, Guy M. McKhann, M. Sean McKisic, David F. Meaney, Minesh P. Mehta, Vivek Mehta, William P. Melega, Arnold H. Menezes, Patrick Mertens, Fredric B. Meyer, Scott A. Meyer, Philip M. Meyers, Costas Michaelides, Karine Michaud, Rajiv Midha, Vincent J. Miele, Jonathan Miller, Matthew L. Miller, Neil R. Miller, John Mitrofanis, Kevin Y. Miyashiro, J. Mocco, Michael T. Modic, Parham Moftakhar, Avinash Mohan, Stephen J. Monteith, Jacques J. Morcos, Michael Morgan, David E. Morris, S. David Moss, J. Paul Muizelaar, Karim Mukhida, Praveen V. Mummaneni, Gregory J.A. Murad, Karin Muraszko, Antônio C.M. Mussi, Imad Najm, Peter Nakaji, Sandra Narayanan, David W. Newell, M. Kelly Nicholas, Yasunari Niimi, Shahid M. Nimjee, Ajay Niranjan, Richard B. North, Josef Novotny, Turo Nurmikko, Samuel E. Nutt, W. Jerry Oakes, José A. Obeso, Alfred T. Ogden, Lissa Ogieglo, Christopher S. Ogilvy, David O. Okonkwo, Michael S. Okun, Edward H. Oldfield, Alessandro Olivi, Stephen E. Olvey, David Omahen, Brent O'Neill, Rod J. Oskouian, Robert Owen, Koray Özduman, Ali Kemal Ozturk, M. Necmettin Pamir, Dachling Pang, Jamie Pardini, Andrew D. Parent, T.S. Park, Michael D. Partington, Aman B. Patel, Parag G. Patil, Nicola Pavese, Richard D. Penn, Noel I. Perin, John A. Persing, Erika A. Petersen, Anthony L. Petraglia, Brigitte Piallat, Joseph H. Piatt, John D. Pickard, Joseph M. Piepmeier, Webster H. Pilcher, José Pineda, Joseph D. Pinter, Mary L. Pisculli, Thomas Pittman, Ian F. Pollack, Pierre Pollak, Bruce E. Pollock, Francisco A. Ponce, Alyx B. Porter, Randall W. Porter, Kalmon D. Post, Alexander K. Powers, Mark R. Proctor, Robert W. Prost, Jeffrey Pugh, Alfredo Quiñones-Hinojosa, Corey Raffel, Sharad Rajpal, Leonardo Rangel-Castilla, Ganesh Rao, Ahmed Raslan, Peter A. Rasmussen, Dibyendu K. Ray, Shaan M. Raza, Davis L. Reames, Chandan G. Reddy, Andy J. Redmond, Jean Régis, Peter L. Reilly, Dominique Renier, Daniel K. Resnick, Renee Reynolds, Ali R. Rezai, Laurence D. Rhines, Albert L. Rhoton, Teresa Ribalta, R. Mark Richardson, Daniele Rigamonti, Gregory J. Riggins, Jay Riva-Cambrin, Paolo Rizzo, David W. Roberts, Claudia Robertson, Lawrence Robinson, Shenandoah Robinson, Pierre-Hugues Roche, Mark A. Rockoff, Gerald E. Rodts, Pantaleo Romanelli, Mark L. Rosenblum, Joshua M. Rosenow, Michael K. Rosner, Eric S. Rovner, Christina L. Runge-Samuelson, Stephen M. Russell, James T. Rutka, Oren Sagher, Eric G. St. Clair, Madjid Samii, Prakash Sampath, Srinath Samudrala, Nader Sanai, Robert A. Sanford, Paul Santiago, Teresa Santiago-Sim, Harvey B. Sarnat, Raymond Sawaya, W. Michael Scheld, Wouter I. Shirzadi, Nicholas D. Schiff, Clemens M. Schirmer, David Schlesinger, Meic H. Schmidt, Joost W. Schouten, Johannes Schramm, Thomas C. Schuler, James M. Schuster, Theodore H. Schwartz, Judith A. Schwartzbaum, Patrick M. Schweder, R. Michael Scott, Eric Seigneuret, Nathan R. Selden, Warren R. Selman, Christopher I. Shaffrey, Manish N. Shah, Kiarash Shahlaie, William R. Shapiro, Deepak Sharma, Jason P. Sheehan, Jonas M. Sheehan, Arun K. Sherma, James M. Shiflett, Helen A. Shih, Jay L. Shils, Alexander Y. Shin, Ali Shirzadi, Adnan H. Siddiqui, Marc Sindou, Konstantin V. Slavin, Edward R. Smith, Justin S. Smith, Yoland Smith, Matthew D. Smyth, Penny K. Sneed, Brian J. Snyder, Kenneth V. Snyder, Robert A. Solomon, Volker K.H. Sonntag, Leif Sørensen, Sulpicio G. Soriano, Mark M. Souweidane, Julian Spears, David Spencer, Dennis D. Spencer, Robert F. Spetzler, Robert J. Spinner, Brett R. Stacey, William C. Stacey, Robert M. Starke, Philip A. Starr, Gary K. Steinberg, Frederick L. Stephens, Barney J. Stern, Charles B. Stevenson, Eric Stiner, Scellig Stone, Nicole L. Stroud, Robert Morgan Stuart, Brian R. Subach, Patrick A. Sugrue, Dima Suki, Wale A.R. Sulaiman, Daniel L. Surdell, William W. Sutherling, Leslie N. Sutton, Omar N. Syed, Michele Tagliati, Yasushi Takagi, Rafael J. Tamargo, Caroline C. Tan, Nitin Tandon, Marcos Tatagiba, Michael D. Taylor, Steven A. Telian, Charles Teo, Jeffrey M. Tessier, Khoi D. Than, Kamal Thapar, Nicholas Theodore, B. Gregory Thompson, Robert Tiel, Tarik Tihan, Ann Tilton, Shelly D. Timmons, Maria Toledo, Tadanori Tomita, Nestor D. Tomycz, Napoleon Torres, Charles P. Toussaint, Bruce D. Trapp, Vincent C. Traynelis, R. Shane Tubbs, Luis M. Tumialán, Allan R. Tunkel, Atsushi Umemura, Alexander R. Vaccaro, Koen van Besien, Jerrold L. Vitek, Kenneth P. Vives, Timothy W. Vogel, Michael A. Vogelbaum, Dennis G. Vollmer, Gretchen K. Von Allmen, Kajetan L. von Eckardstein, P. Ashley Wackym, Mark Wainwright, Ben Waldau, Marion L. Walker, M. Christopher Wallace, Brian Walsh, Huan Wang, Michael Y. Wang, Vincent Y. Wang, Ronald E. Warnick, Sharon Webb, Ralf Weigel, Robert J. Weil, Jon D. Weingart, Bryce Weir, Martin Weiss, Nirit Weiss, William C. Welch, John C. Wellons, Hung Tzu Wen, Christian Wess, G. Alexander West, Nicholas M. Wetjen, Robert G. Whitmore, Louis A. Whitworth, Thomas Wichmann, Joseph L. Wiemels, Eelco F.M. Wijdicks, Adam C. Wilberger, Jack Wilberger, David M. Wildrick, Jason Wilson, Christopher J. Winfree, H. Richard Winn, Christopher Wolfla, Eric T. Wong, Peter J. Wormald, Margaret Wrensch, Neill M. Wright, Zachary Wright, David Yam, Shinya Yamada, Yoshiya Yamada, Isaac Yang, Victor X.D. Yang, Tom Yao, Chun-Po Yen, H. Kwang Yeoh, Yasuhiro Yonekawa, Alice Yoo, David M. Yousem, Eric C. Yuen, Joseph M. Zabramski, Andrew C. Zacest, J. Christopher Zacko, Gabriel Zada, Ross Zafonte, Eric L. Zager, Hasan A. Zaidi, Hekmat Zarzour, Vasilios A. Zerris, Justin A. Zivin, John G. Zovickian, Alexander Y. Zubkov, and Marike Zwienenberg-Lee

Published
2011
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9. Bioabsorbable instrumentation for single-level cervical degenerative disc disease: a radiological and clinical outcome study

Author

Andre, Tomasino, Harry, Gebhard, Karishma, Parikh, Christian, Wess, and Roger, Härtl

Subjects
Adult, Male, Intervertebral Disc Degeneration, Middle Aged, Radiography, Postoperative Complications, Spinal Fusion, Treatment Outcome, Absorbable Implants, Humans, Female, Kyphosis, Diskectomy, Follow-Up Studies, Retrospective Studies
Abstract

The authors present the radiological and clinical outcome data obtained in patients who underwent single-level anterior cervical discectomy and fusion (ACDF) for cervical spondylosis and/or disc herniation; bioabsorbable plates were used for instrumentation. The use of metallic plates in ACDF has gained acceptance as a stabilizing part of the procedure to increase fusion rates, but when complications occur with these devices, the overall effectiveness of the procedure is compromised. As a possible solution, bioabsorbable implants for ACDF have been developed. This study investigates the feasibility and radiological and clinical outcomes of the bioabsorbable plates for ACDF.The radiological and clinical outcomes of 30 patients were investigated retrospectively. All patients presented with cervical radiculopathy or myelopathy and underwent single-level ACDF in which a bioabsorbable anterior cervical plate and an allograft bone spacer were placed at a level between C-3 and C-7. Radiological outcome was assessed based on the fusion rate, subsidence, and Cobb angle of the surgical level. Clinical outcome was determined by using a visual analog scale, the Neck Disability Index, and the Odom criteria.There were no intraoperative complications, and no hardware failure was observed. No signs or symptoms of adverse tissue reaction caused by the implant were seen. Two reoperations were necessary due to postoperative blood collections. The overall complication rate was 16.7%. After 6 months, radiographic fusion was seen in 92.3% of patients. Subsidence at 11.3 +/- 7.2 months was 3.1 +/- 5.8 mm (an 8.2% change over the immediately postoperative results), and the change in the sagittal curvature was -2.7 +/- 2.7 degrees . The visual analog scale score for neck and arm pain and Neck Disability Index improved significantly after surgery (p0.001). Overall at 19.5 months postoperatively, 83% of the patients had favorable outcomes based on the Odom criteria.Absorbable instrumentation provides better stability than the absence of a plate but graft subsidence and deformity rates may be higher than those associated with metal implants. There were no device-related complications, but adverse late effects cannot be excluded. The fusion rate and outcome are comparable to the results achieved with metallic plates. The authors were satisfied with the use of bioabsorbable plates as a reasonable alternative to metal, avoiding the need for lifelong metallic implants.

Published
2009

10. Spectral iEEG markers precede SSEP events during surgery for subarachnoid hemorrhage

Author

Christian Wess, Ekkehard Kunze, Johannes Sarnthein, Jürgen Meixensberger, Niklaus Krayenbühl, Markus Scholz, University of Zurich, and Sarnthein, J

Subjects
Adult, Male, medicine.medical_specialty, Subarachnoid hemorrhage, Early detection, 610 Medicine & health, Electroencephalography, Vascular occlusion, 10180 Clinic for Neurosurgery, 2809 Sensory Systems, 2737 Physiology (medical), Predictive Value of Tests, Physiology (medical), Evoked Potentials, Somatosensory, Monitoring, Intraoperative, Occlusion, medicine, Reaction Time, Humans, Electrodes, Aged, medicine.diagnostic_test, business.industry, Spectrum Analysis, Middle Aged, Subarachnoid Hemorrhage, medicine.disease, Predictive value, Sensory Systems, Electric Stimulation, Surgery, 2728 Neurology (clinical), Neurology, Somatosensory evoked potential, Anesthesia, 2808 Neurology, Feasibility Studies, Female, Neurology (clinical), medicine.symptom, Tibial Nerve, business, Cerebrovascular surgery
Abstract

Objective During neurosurgical intracranial vascular manipulations, surgeons need early feed-back on the effects of temporary vascular occlusion. In surgical practice, commonly the amplitude of somatosensory evoked potentials (SSEP) is monitored. However, the latency between an ischemic event and the drop of SSEP amplitude may amount to several minutes. Therefore intracranial electroencephalogram (iEEG) is tested for its predictive value. Methods During surgery in 13 patients, SSEP was recorded simultaneously with iEEG. iEEG was analyzed real-time in the frequency domain. Spectral observables of the iEEG were validated on the basis of SSEP by computing the statistical correlation first for the whole data set, then for salient events occurring in the SSEP in the group of patients, and finally for salient events occurring in single patients. Results Placement of subdural strip electrodes was compatible with standard surgical routine. Maximal correlation between time series of iEEG and SSEP was found for relative alpha power, which preceded the drop of SSEP by 7 min. Conclusions iEEG is feasible during neurosurgical intracranial vascular manipulations. Monitoring relative alpha power detects salient events earlier than SSEP. Significance Early detection of salient events facilitates early reaction of the surgeon and may thereby aid to further reduce intraoperative morbidity.

Published
2009

11. Continuous hypertonic saline therapy and the occurrence of complications in neurocritically ill patients

Author

Christian Wess, Igor Ougorets, Quanhong Ni, Roger Härtl, and Matteus Froelich

Subjects
Male, medicine.medical_specialty, Subarachnoid hemorrhage, Critical Illness, Critical Care and Intensive Care Medicine, Kidney, law.invention, law, Intensive care, medicine, Humans, Stroke, Retrospective Studies, Saline Solution, Hypertonic, integumentary system, business.industry, Glasgow Coma Scale, Middle Aged, Subarachnoid Hemorrhage, medicine.disease, Intensive care unit, Hypertonic saline, Surgery, Anesthesia, Brain Injuries, Female, Hypernatremia, business, Kidney disease
Abstract

To evaluate potential side effects of continuous hypertonic 3% saline (CHS) as maintenance fluid in patients with brain injury.Retrospective chart analysis of prospectively collected data.Patients admitted to the neurosurgical intensive care unit for4 days with traumatic brain injury, stroke, or subarachnoid hemorrhage with a Glasgow Coma Scale9 and elevated intracranial pressure (ICP) or at risk of developing elevated ICP were included. Based on physician preference, one group was treated with 3% CHS at a rate of 1.5 mL/kg/bw as maintenance fluid. The other group received 0.9% normal saline (NS). Two percent saline was used in the CHS group to wean patients off 3% CHS or when sodium was above 155. Data on serum sodium, blood urea nitrogen, creatinine, ICP, infection rate, length of stay, rates of deep vein thrombosis, and pulmonary emboli and dural thrombosis were collected prospectively.One hundred seven patients in the CHS group and 80 in the NS group met the inclusion criteria. The incidence of moderate hypernatremia (Na155 mmol/L) and severe hypernatremia (Na160 mmol/L) was significantly higher in the CHS therapy group than in the NS group. No significant relationship between CHS infusion and renal dysfunction was found. Moderate and severe hypernatremia was associated with a higher risk of elevated blood urea nitrogen and creatinine levels. Acute renal failure was not seen in these patients. A total of 53.3% in the CHS group and in 16.3% in the NS group (p0.0001) had raised ICP (25 mm Hg), consistent with the physicians decision to use CHS in patients with elevated ICP.CHS therapy was not associated with an increased rate of infection, deep vein thrombosis, or renal failure. However, there was a significant risk of developing hypernatremia. We conclude that CHS administration in patients with severe injuries is safe as long as sodium levels are carefully monitored.

Published
2009

12. Peripheral neurostimulation for treatment of intractable occipital neuralgia

Author

Christian Wess, Hrachya Nersesyan, and Konstantin V. Slavin

Subjects
Adult, Male, medicine.medical_specialty, Visual analogue scale, medicine.medical_treatment, Electric Stimulation Therapy, Neurological disorder, Occipital neuralgia, medicine, Humans, Peripheral Nerves, Neurostimulation, Device Removal, Retrospective Studies, business.industry, Retrospective cohort study, Equipment Design, Middle Aged, medicine.disease, Surgery, Electrodes, Implanted, Pain, Intractable, Peripheral nerve field, Treatment Outcome, Anesthesia, Occipital Bone, Neuralgia, Intractable pain, Female, Neurology (clinical), business
Abstract

OBJECTIVE: Medically intractable pain caused by occipital neuralgia (ON) can be very difficult to control with traditional pain management. Peripheral nerve stimulation (PNS) may serve as a good alternative to destructive surgical manipulations used currently for the treatment of severe ON. METHODS: We analyzed records of 14 consecutive patients (9 women and 5 men; mean age, 43.3 yr) with intractable ON treated with PNS during the period from April 2002 to November 2004. Five patients had unilateral and nine had bilateral PNS electrodes inserted for trial, which was considered successful if patient reported at least 50% decrease of pain on the visual analogue scale. Ten patients proceeded with system internalization, and their long-term results were analyzed. RESULTS: At the time of the last follow-up examination (5–32 mo, mean 22 mo), seven patients (70%) with implanted PNS systems continue to experience beneficial effects of stimulation, including adequate pain control, continuous employment, and decrease in oral pain medications intake. Two patients had their systems explanted because of loss of stimulation effect or significant improvement of pain, and one patient had part of his hardware removed because of infection. CONCLUSION: Overall, the beneficial effect from chronic stimulation in our series persisted in more than half of the patients for whom procedure was considered and in 80% of those who significantly improved during the trial and proceeded with internalization. Thus, chronic PNS may be a safe and relatively effective method for long-term treatment of chronic pain syndrome in patients with medically intractable ON.

Published
2005

13. Jenseits von Äpfeln und Birnen – Studienverläufe vergleichend analysieren

Author

Christian Weßels, Katharina Pletz, and Michael Koch

Subjects
Education
Abstract

Durch die einheitliche Aufbereitung der Studierenden- und Prüfungsdaten wird eine vergleichende Analyse von Studienverläufen innerhalb des Verbunds Norddeutscher Universitäten möglich. Die Gegenüberstellung fachgleicher Studiengänge anhand von Erfolgsindikatoren soll dazu dienen, fachspezifische Diskurse zur Qualitätsentwicklung an den Mitgliedsuniversitäten anzustoßen. Auf Basis eines Arbeitsmodells wird davon ausgegangen, dass sich die Studierbarkeit aus dem Zusammenwirken und der Passfähigkeit von institutionellen und individuellen Faktoren ergibt und Unterschiede zwischen den Studienorten mittelbar auf Unterschiede in der Studierbarkeit der Studienprogramme verweisen.

Published
2021
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16. Methodological Challenges by (New) Media. An Essay on Perspectives and Possible Consequences

Author

Christian Wessely

Subjects
media analysis, communication spaces, media literacy, concept of meaning, Communication. Mass media, P87-96, Religion (General), BL1-50
Abstract

The classical concept of media analysis depends to a large extent on linearity, but modern interactive media are mostly non-linear. Roger Odin has suggested a method for working with such interactive media; however, the approach he suggests creates a new problem. What would be an appropriate way to deal with the dilemma of balancing sufficient intersubjectivity and concessions to non-linearity?

Published
2015

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