title: Functional and physical outcomes following use of a flexible CO2 laser fiber and bipolar electrocautery in close proximity to the rat sciatic nerve with correlation to an in vitro thermal profile model.
abstract: This study compared functional and physical collateral damage to a nerve when operating a Codman MALIS Bipolar Electrosurgical System CMC-III or a CO2 laser coupled to a laser, with correlation to an in vitro model of heating profiles created by the devices in thermochromic ink agarose. Functional damage of the rat sciatic nerve after operating the MALIS or CO2 laser at various power settings and proximities to the nerve was measured by electrically evoked nerve action potentials, and histology of the nerve was used to assess physical damage. Thermochromic ink dissolved in agarose was used to model the spatial and temporal profile of the collateral heating zone of the electrosurgical system and the laser ablation cone. We found that this laser can be operated at 2 W directly above the nerve with minimal damage, while power settings of 5 W and 10 W resulted in acute functional and physical nerve damage, correlating with the maximal heating cone in the thermochromic ink model. MALIS settings up to 40 (11 W) did not result in major functional or physical nerve damage until the nerve was between the forceps tips, correlating with the hottest zone, localized discretely between the tips.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Northwestern University, 303 E. Chicago Avenue, Searle 12-561, Chicago, IL 60611, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Robinson
authors.affiliation: Cadence Neuroscience Institute at Northwestern Medicine, 25 N. Winfield Road, Winfield, IL 60190, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Fishman
authors.affiliation: Department of Neurological Surgery, Northwestern University, 676 North St. Clair, Chicago, IL 60611, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Bendok
authors.affiliation: Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL 60208, USA ; The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Drive, Evanston, IL 60208, USA ; Department of Otolaryngology Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Searle Building 12-470, 303 E. Chicago Avenue, Chicago, IL 60611-3008, USA.
authors.forename: C-P
authors.initials: CP
authors.lastname: Richter
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000627:therapeutic use*; D004564:Electrocoagulation / Q000379:methods; D005260:Female; D005336:Fiber Optic Technology / Q000379:methods; D053685:Laser Therapy / Q000379:methods; D007834:Lasers; D054020:Lasers, Gas / Q000627:therapeutic use*; D008297:Male; D051381:Rats; D012584:Sciatic Nerve / Q000601:surgery*; D013525:Surgical Instruments
chemical_list: D002245:Carbon Dioxide