2026 Poster Presentations
P095: KEYHOLE RETROSIGMOID APPROACH - SURGICAL TECHNIQUE AND TECHNICAL NUANCES
Lydia Kaoutazani, MD; Christopher Carr, MD; David Baker, MD; Fernando Vale-Enrique; Luca Debs, MD; Shannon Derthick; Fernando Vale, MD; M. Salman Ali, MD; Medical College of Georgia at Augusta University
Introduction: Numerous variations of retrosigmoid approach (RSA) have been described previously including incisions, craniotomies and closures. Here, we describe our minimally invasive keyhole RSA to treat various pathologies ranging from microvascular decompression to large tumors.
Methods: Cases performed by senior author in first 18 months since the completion of the fellowship were reviewed. Surgical approach and outcomes were reviewed.
Results: Surgical approach (Figure 1) – Patients are placed in supine position with or without a shoulder bump. Somatosensory evoked potentials are used pre and post-positioning. Head is turned to the contralateral side and translated superiorly to clear the shoulders. Neuro-navigation is used in all cases. Mannitol is used in all cases, administered at the time of incision. A linear or slightly curvilinear incision is made two finger breadth posterior to the external auditory canal. The length of the incision ranges from 2-4 inches based on the proximity of the lesion to the surface. The rostro-caudal location of the incision is determined by the location of the pathology. Incision is made with the blade down to the bone. Sub-periosteal dissection is performed with a Penfield-1. Use of electrocautery is minimized to prevent damage to the muscle layers. Hooks are used retract the myocutaneous flaps medial and lateral. A single burrhole is made at the transverse-sigmoid junction. Using a craniotome, bone flap is elevated. We never perform craniectomy. Further drilling is performed to expose at least 1/3rd of sigmoid sinus. Transverse sinus exposure depends on the rostral location of the pathology and is usually performed along with the original craniotomy after careful extradural dissection. The dura is opened at the caudal end first, enough to pass a 1x3 cottonoid. Cerebellomedulary cistern is opened with sharp dissection to release cerebrospinal fluid. Remaining dura is opened in a C-shaped fashion with the base towards the sigmoid sinus. No fixed retraction was used in any case. Endoscope was frequently used. Closure is performed either primarily or with the help of bovine pericardium. A piece of onlay dural substitute is placed. Bone is replaced to tamponade the closure. Circumferential bony defect is filled with Surgicel. Hemostatic sealants are never used. Wound is closed in a multi-layered fashion.
Outcomes – 27 patients were identified who underwent this approach. Demographics, indications and complications are listed in figure 2. No CSF leaks, infections or pseudomeningoceles were identified in our series (Figure 3). All facial palsies resolved 3 months post-op.
Limitations – Our approach is based on keyhole concept. Use of endoscope is essential in majority of the cases.
Conclusions: This minimally invasive keyhole and retractorless approach provides adequate exposure to handle even large tumors coupled with excellent cosmetic results. Use of endoscope is necessary in some cases. Familiarity with surgical anatomy and comfort with working in a small surgical corridor is essential.
