title: Modified skin incision for avoiding the lesser occipital nerve and occipital artery during retrosigmoid craniotomy: potential applications for enhancing operative working distance and angles while minimizing the risk of postoperative neuralgias and intraoperative hemorrhage.
abstract: Chronic postoperative neuralgias and headache following retrosigmoid craniotomy can be uncomfortable for the patient. We aimed to better elucidate the regional nerve anatomy in an effort to minimize this postoperative complication. Ten adult cadaveric heads (20 sides) were dissected to observe the relationship between the lesser occipital nerve and a traditional linear versus modified U incision during retrosigmoid craniotomy. Additionally, the relationship between these incisions and the occipital artery were observed. The lesser occipital nerve was found to have two types of course. Type I nerves (60%) remained close to the posterior border of the sternocleidomastoid muscle and some crossed anteriorly over the sternocleidomastoid muscle near the mastoid process. Type II nerves (40%) left the posterior border of the sternocleidomastoid muscle and swung medially (up to 4.5cm posterior to the posterior border of the sternocleidomastoid muscle) as they ascended over the occiput. The lesser occipital nerve was near a midpoint of a line between the external occipital protuberance and mastoid process in all specimens with the type II nerve configuration. Based on our findings, the inverted U incision would be less likely to injure the type II nerves but would necessarily cross over type I nerves, especially more cranially on the nerve at the apex of the incision. As the more traditional linear incision would most likely transect the type I nerves and more so near their trunk, the U incision may be the overall better choice in avoiding neural and occipital artery injury during retrosigmoid approaches.
authors.affiliation: Seattle Science Foundation, Seattle, WA 98122, USA; Department of Anatomical Sciences, St. George's University, Grenada; Centre of Anatomy and Human Identification, University of Dundee, DD1 4HN, Scotland, UK.
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.affiliation: Saarland University Medical Center and Saarland University Faculty of Medicine, D66424 Homburg, Germany.
authors.forename: Fabian N
authors.initials: FN
authors.lastname: Fries
authors.affiliation: Goodman Campbell Brain and Spine, Department of Neurological Surgery, Indiana University School of Medicine, 355 W. 16th Street, Suite #5100, Indianapolis, IN 46202, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Kulwin
authors.affiliation: California Brain Institute, Los Robles Hospital and Medical Center, Thousand Oaks, CA 91360, USA.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Mortazavi
authors.affiliation: Department of Anatomical Sciences, St. George's University, Grenada.
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
authors.affiliation: Goodman Campbell Brain and Spine, Department of Neurological Surgery, Indiana University School of Medicine, 355 W. 16th Street, Suite #5100, Indianapolis, IN 46202, USA. Electronic address: acohenmd@gmail.com.
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Cohen-Gadol
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D002536:Cerebral Arteries / Q000473:pathology / Q000601:surgery*; D003399:Craniotomy / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000209:etiology / Q000517:prevention & control*; D009777:Occipital Bone / Q000473:pathology / Q000601:surgery; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control*; D013127:Spinal Nerves / Q000473:pathology / Q000601:surgery; D000072836:Surgical Wound / Q000209:etiology / Q000517:prevention & control
keywords: Anatomy; Lesser occipital nerve; Nerves; Occiput; Retrosigmoid craniotomy