Introduction: Retrosigmoid craniotomy has been shown to carry a small risk of post-operative headache that can often be severe and refractory to medication. Previous literature on etiology hypothesized intra-dural bone drilling, injury to the occipital nerve, and cranioplasty technique to be potential causes. A minimally invasive keyhole retrosigmoid craniectomy with anatomic muscle dissection works to minimize the extradural contributors of post-operative headache.

Methods: A retrospective chart review was performed. 12 patients, average age 59 years (range 35-83 years) underwent retrosigmoid craniotomy, with the pathologies listed in Table 1. In the operating room, each patient was placed in the lateral position and a curvilinear incision was made within three centimeters posterior to the ear. A galeocutaneous flap is elevated and retracted anteriorly along the plane superficial to the spenius capitus muscle. Special attention was made to avoid cutting across the sternocleidomastoid as this is elevated along with the flap. The splenius capitus muscle is elevated separately and retracted posteriorly (Figure 1). A craniectomy was performed, and reconstructed with titanium mesh on closure. The splenius is then reapproximated and the galea is closed.

Results: The follow-up period ranged from 1-8 months. There were no incidents of intracranial bleeding, infection or wound complications, including CSF leak or pseudomeningocele formation. There were no new cranial nerve deficits. On telephone follow-up, all patients reported no headache and were given a Grade 0 as described by Catalano. All patients reported satisfactory cosmetic benefit, with no evidence of muscle atrophy in the scalp or neck area.

Conclusions: Using minimally invasive approaches to the posterior fossa has promising results when considering patient’s incidence of new post-operative headache. Respecting the muscle attachments coursing deep to a retroauricular incision may contribute to the benefit of this approach.

Patient Care: Despite many hypothesized etiologies that contribute to post-operative headache, it still occurs following the retrosigmoid approach and may be resistant to medication. Our research attempts to minimize these hypothesized contributors to post-operative headache to determine if our technique is associated with better clinical outcomes in patients.

Learning Objectives: By the conclusion of this session, participants should be able to 1) Understand the extradural factors hypothesized to contribute to post-operative headache following retrosigmoid craniotomy 2) Discuss the variety of pathologies served by a retrosigmoid approach 3) Identify methods of minimizing trauma to the muscular attachments that underlie a retroauricular incision

References: 1. Ducic I, Felder JM, 3rd, Endara M. Postoperative headache following acoustic neuroma resection: occipital nerve injuries are associated with a treatable occipital neuralgia. Headache 2012;52:1136-1145. 2. Catalano PJ, Jacobowitz O, Post KD. Prevention of headache after retrosigmoid removal of acoustic tumors. Am J Otol 1996;17:904-908.