Retrosigmoid Craniectomy Research Articles

Retrosigmoid Intradural Suprameatal Approach: 2-Dimensional Operative Video

INDICATIONS: CORRIDOR AND LIMITS OF EXPOSURE: The retrosigmoid intradural suprameatal approach is mostly indicated for tumors in the cerebellopontine angle extending toward the Meckel cave and supratentorial regions, most frequently meningiomas and schwannomas. This approach was first established by the senior author in 1982. ANATOMIC ESSENTIALS: NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Nervous structures: cranial nerves III to XII, cerebellum, and brainstem. Vascular structures: anterior inferior cerebellar artery, posterior inferior cerebellar artery, superior cerebellar artery, basilar artery, vertebral artery, transverse, sigmoid, and petrous sinus, petrosal vein/veins, basilar plexus, and the mastoid emissary vein. Bony structures: petrous bone with internal auditory canal, jugular foramen and suprameatal tubercle, petrous apex, dorsum sellae, and posterior clinoid process. Structures within the petrous bone: vestibule, semicircular canals, and jugular bulb. ESSENTIALS STEPS OF THE PROCEDURE: After a suboccipital retrosigmoid craniectomy in the semisitting position and debulking of the tumor mass in the cerebellopontine angle, extension is achieved by drilling suprameatal tubercle above cranial nerve VII and VIII toward the petrous apex. The extent of bone drilling is tailored for each patient. PITFALLS/AVOIDANCE OF COMPLICATIONS: Avoid damage to cranial nerves, arteries, and veins during drilling, dissection, and tumor removal or by retraction. VARIANTS AND INDICATIONS FOR THEIR USE: In case of extreme supratentorial extensions laterally and dorsally, the opening of the tentorium may be helpful. For inferior extensions toward the upper spinal canal, opening of the foramen magnum and hemilaminectomy of C1 may be necessary. The patient consented to the procedure and to the publication of his/her image. Institutional logo in title slide, © 2023, INI Hannover. Used with permission.

Ondine's curse: clinical presentation with diaphragmatic pacing and spontaneous respiratory recovery. Illustrative case.

The complexity of posterior fossa surgery can often lead to rare complications due to the anatomy involved. Vestibular schwannoma resection is a common pathology in the posterior fossa, often requiring surgical intervention. Given the proximity of this space to the brainstem, cranial nerve VII/VIII complex, and posterior inferior cerebellar artery (PICA), neurovascular complications are not infrequent. A rare vascular complication from this surgical approach is a lateral medullary infarction from injury to the lateral medullary segment of the proximal PICA, leading to central hypoventilation syndrome (CHS). This report presents a unique case of a 51-year-old man who underwent a retrosigmoid craniectomy for resection of a vestibular schwannoma. Following surgery, the patient was unable to be weaned off the ventilator and was noted to become apneic while he slept, a clinical picture consistent with Ondine's curse. This report discusses the anatomical considerations of this surgical corridor leading to this complication and the management of a patient with acquired Ondine's curse and reviews the scarce literature on this uncommon cause of acquired CHS.

Nervus intermedius: Microsurgical and anatomic relationships to the cerebellopontine angle neurovascular complex.

The nervus intermedius (NI) comprises fibers originating from the trigeminal, superior salivary, and solitary tract nuclei, which join the facial nerve (cranial nerve [CN] VII). Neighboring structures include the vestibulocochlear nerve (CN VIII), the anterior inferior cerebellar artery (AICA), and its branches. Microsurgical procedures at the cerebellopontine angle (CPA) benefit from understanding NI anatomy and relationships, especially for the microsurgical treatment of geniculate neuralgia, where the NI is transected. This study sought to characterize common relationships between the NI rootlets, CN VII, CN VIII, and the meatal loop of AICA at the internal auditory canal (IAC). Seventeen cadaveric heads underwent retrosigmoid craniectomy. Following complete unroofing of the IAC, the NI rootlets were individually exposed to identify their origins and insertion points. The AICA and its meatal loop were traced to assess their relationship with the NI rootlets. Thirty-three NIs were identified. The median number of NI rootlets was 4 per NI (interquartile range, 3-5). The rootlets mainly originated from the proximal premeatal segment of CN VIII (81 of 141, 57%) and inserted onto CN VII at the IAC fundus (89 of 141, 63%). When crossing the acoustic-facial bundle, the AICA most frequently passed between the NI and CN VIII (14 of 33, 42%). Five composite patterns of neurovascular relationships were identified regarding NI. Although certain anatomical trends can be identified, the NI has a variable relationship with the adjacent neurovascular complex at the IAC. Therefore, anatomical relationships should not be used as the sole method of NI identification during CPA surgery.

Dispersed Bone Spicules as a Cause of Postoperative Headache after Retrosigmoid Vestibular Schwannoma Surgery: A Myth?

Objectives Dispersion of bone dust in the posterior fossa during retrosigmoid craniectomy for vestibular schwannoma (VS) resection could be a source of meningeal irritation and lead to development of persistent postoperative headaches (POH). We aim to determine risk factors, including whether the presence of bone spicules that influence POH after retrosigmoid VS resection. Design Present study is a retrospective case series. Setting The study was conducted at a tertiary skull-base referral center. Participants Adult patients undergoing VS resection via a retrosigmoid approach between November 2017 and February 2020 were included for this study. Main Outcome Measures Development of POH lasting ≥ 3 months is the primary outcome of this study. Results Of 64 patients undergoing surgery, 49 had complete data (mean age, 49 years; 53% female). Mean follow-up time was 2.4 years. At latest follow up, 16 (33%) had no headaches, 14 (29%) experienced headaches lasting <3 months, 19 (39%) reported POH lasting ≥3 months. Twenty-seven (55%) patients had posterior fossa bone spicules detectable on postoperative computed tomography (CT). Age, gender, body mass index, length of stay, tumor diameter, size of craniectomy, the presence of bone spicules, or the amount of posterior petrous temporal bone removed from drilling did not differ significantly between patients with POH and those without. On multivariate logistic regression, patients with POH were less likely to have preoperative brainstem compression by the tumor (odds ratio [OR] = 0.21, p = 0.028) and more likely to have higher opioid requirements during hospitalization (OR = 1.023, p = 0.045). Conclusion The presence of bone spicules in the posterior fossa on postoperative CT did not contribute to headaches following retrosigmoid craniectomy approach for VS resection.

Retrosigmoid Craniectomy and Suprameatal Drilling-3-Dimensionally Printed Microneurosurgical Simulation: 2-Dimensional Operative Video.

Neurosurgical training is being challenged by rigorous work-hour restrictions and the COVID-19 pandemic.1 Now, more than ever, surgical simulation plays a pivotal role in resident education and psychomotor skill development. Three-dimensional (3D) printing technologies enable the construction of inexpensive, patient-specific, anatomically accurate physical models for a more convenient and realistic simulation of complex skull base approaches in a safe environment.2 All stages of the surgical procedure can be simulated, from positioning and exposure to deep microdissection, which has an unparalleled educational value. The complex approach-specific anatomy, narrow working angles, and pathoanatomic relationships can be readily explored from the surgeon's perspective or point of view.2,3 Furthermore, different thermoplastic polymers can be utilized to replicate the visual and tactile feedback of bone (cortical/cancellous), neurological, and vascular tissues.4 Retrosigmoid craniectomies are widely used in neurosurgery with various applications, including microvascular decompressions in patients with trigeminal neuralgia.5-7 Removal of the suprameatal tubercle (SMT) extends the retrosigmoid approach superiorly to the middle fossa and Meckel's cave, and anteriorly to the clivus.8,9 This maneuver may be necessary in patients with prominent SMTs obstructing the view of the trigeminal nerve and in patients with a more anterosuperior neurovascular conflict. This video illustrates a microsurgical training tool for learning and honing the technique of retrosigmoid craniectomy and suprameatal drilling using an affordable (29.00 USD) biomimetic 3D-printed simulator that closely recapitulates not only the anatomy but also the tactile feedback of drilling and manipulating neurological tissues (see Table and Graph 1; minute 07:11) as it happens at the time of surgery.

Selective Neurectomy of the Vestibular nerve through a Retrosigmoid approach for the Treatment of vertigo in Ménière's Disease

Ménière's disease (also known as Ménière's vertigo) is a condition characterized by disabling recurrent vertigo, sensorineural hearing loss, otic fullness, and tinnitus. There are various treatments to manage this entity, however, in certain cases, the lack of improvement with less aggressive strategies and the great impact on the quality of life of the patient requires radical procedures such as vestibular neurectomy. By means of a lateral suboccipital approach (retrosigmoid craniectomy) the best exposure of the vestibular nerve, its selective isolation and section is obtained, also allowing to preserve hearing and the entire facial nerve supported with neurophysiological monitoring techniques.

Retrosigmoid Craniectomy with a Layered Soft Tissue Dissection and Hydroxyapatite Reconstruction: Technical Note, Surgical Video, Regional Anatomy, and Outcomes.

Introduction There are many reported modifications to the retrosigmoid approach including variations in skin incisions, soft tissue dissection, bone removal/replacement, and closure. Objective The aim of this study was to report the technical nuances developed by two senior skull base surgeons for retrosigmoid craniectomy with reconstruction and provide anatomic dissections, surgical video, and outcomes. Methods The regional soft tissue and bony anatomy as well as the steps for our retrosigmoid craniectomy were recorded with photographs, anatomic dissections, and video. Records from 2017 to 2019 were reviewed to determine the incidence of complications after the authors began using the described approach. Results Dissections of the relevant soft tissue, vascular, and bony structures were performed. Key surgical steps are (1) a retroauricular C-shaped skin incision, (2) developing a skin and subgaleal tissue flap of equal thickness above the fascia over the temporalis and sub-occipital muscles, (3) creation of subperiosteal soft tissue planes over the top of the mastoid and along the superior nuchal line to expose the suboccipital region, (4) closure of the craniectomy defect with in-lay titanium mesh and overlay hydroxyapatite cranioplasty, and (5) reapproximation of the soft tissue edges during closure. Complications in 40 cases were pseudomeningocele requiring shunt ( n = 3, 7.5%), wound infection ( n = 1, 2.5%), and aseptic meningitis ( n = 1, 2.5%). There were no incisional cerebrospinal fluid leaks. Conclusion The relevant regional anatomy and a revised technique for retrosigmoid craniectomy with reconstruction have been presented with acceptable results. Readers can consider this technique when using the retrosigmoid approach for pathology in the cerebellopontine angle.

Bone Cement Cranioplasty Reduces Cerebrospinal Fluid Leak Rate after Microvascular Decompression: A Single-Institutional Experience.

Background Microvascular decompression (MVD) is a common surgical treatment for cranial nerve compression, though cerebrospinal fluid (CSF) leak is a known complication of this procedure. Bone cement cranioplasty may reduce rates of CSF leak. Objective To compare rates of CSF leak before and after implementation of bone cement cranioplasty for the reconstruction of cranial defects after MVD. Methods Retrospective chart review was performed of patients who underwent MVD through retrosigmoid craniectomy for cranial nerve compression at a single institution from 1998 to 2017. Study variables included patient demographics, medical history, type of closure, and postoperative complications such as CSF leak, meningitis, lumbar drain placement, and ventriculoperitoneal shunt insertion. Cement and noncement closure groups were compared, and predictors of CSF leak were assessed using a multivariate logistic regression model. Results A total of 547 patients treated by 10 neurosurgeons were followed up for more than 20 years, of whom 288 (52.7%) received cement cranioplasty and 259 (47.3%) did not. Baseline comorbidities were not significantly different between groups. CSF leak rate was significantly lower in the cement group than in the noncement group (4.5 vs. 14.3%; p < 0.001). This was associated with significantly fewer patients developing postoperative meningitis (0.7 vs. 5.2%; p = 0.003). Multiple logistic regression model demonstrated noncement closure as the only independent predictor of CSF leak (odds ratio: 3.55; 95% CI: 1.78-7.06; p < 0.001). Conclusion CSF leak is a well-known complication after MVD. Bone cement cranioplasty significantly reduces the incidence of postoperative CSF leak and other complications. Modifiable risk factors such as body mass index were not associated with the development of CSF leak.

Balancing Operative Efficiency and Surgical Education: A Functional Neurosurgery Model.

Attending surgeons have dual obligations to deliver high-quality health care and train residents. In modern healthcare, lean principles are increasingly applied to processes preceding and following surgery. However, surgeons have limited data regarding variability and waste during any given operation. To measure variability and waste during the following key functional neurosurgery procedures: retrosigmoid craniectomy (microvascular decompression [MVD] and internal neurolysis) and deep brain stimulation (DBS). Additionally, we correlate variability with residents' self-reported readiness for the surgical steps. The aim is to guide surgeons as they balance operative safety and efficiency with training obligations. For each operation (retrosigmoid craniectomy and DBS), a standard workflow, segmenting the operation into components, was defined. We observed a representative sample of operations, timing the components, with a focus on variability. To assess perceptions of safety and risk among surgeons of various training levels, a survey was administered. Survey results were correlated with operative variability, attempting to identify areas for increasing value without compromising trainee experience. A sampling of each operation (n=36) was observed during the study period. For MVD, craniectomy had the highest mean duration and standard deviation, whereas the MVD itself had the lowest mean duration and standard deviation. For DBS, the segments with largest standard deviation in duration were registration and electrode placement. For many steps of both procedures, there was a statistically significant relationship between increasing level of training and increasing perception of safety. This proof-of-concept study introduces an educational and process-improvement tool that can be used to aid surgeons in increasing the efficiency of patient care.

Surgical Outcomes After Microvascular Decompression With Internal Neurolysis and Partial Neurectomy for Patients With Trigeminal Neuralgia and Negative Neurovascular Compression

Abstract INTRODUCTION Microvascular decompression (MVD) is an effective and durable treatment for patients with trigeminal neuralgia (TN) due to neurovascular compression (NVC). In the absence of NVC, the traditional MVD is less effective in achieving long-term pain relief. Internal neurolysis at the root entry zone (REZ) of the trigeminal nerve has been described in the literature; however, there are few reports of long-term outcome after this procedure. Furthermore, this is the first study to combine this procedure with additional partial neurectomy. METHODS This is a retrospective review of the senior author's patients with TN who underwent retrosigmoid craniectomy for MVD with internal neurolysis and partial neurectomy. Primary indications were patients with TN and no evidence of NVC intraoperatively. A total of 9 patients were included in the analysis. Three cases were of recurrent TN. The technique was performed with an 11-blade or arachnoid knife to open the perineurium in a longitudinal fashion at the REZ. A disc dissector was used to comb the fascicles along the longitudinal course, and a partial neurectomy was performed with a microscissors to make three selective cuts into the fascicles at the REZ. Barrow Neurological Institute (BNI) facial pain and numbness scales were used as postoperative assessment. RESULTS At median follow up of 12 mo (range: 2 to 34), 8 of 9 patients (89%) had a BNI-pain score of I (no trigeminal pain, no medications). Two of nine patients (22%) had a BNI-numbness score of I (no numbness); seven (78%) had a BNI-numbness score of II (mild facial numbness that is not bothersome). CONCLUSION Internal neurolysis with partial neurectomy appears to be an effective and potentially durable treatment option for patients with TN (primary or recurrent) without NVC. Larger series with longer follow-up is indicated to further evaluate the utility of this procedure.

Symptom: Postauricular Mass

Symptom: Postauricular Mass

Posterior Approach to Meckel's Cave: Retrosigmoid Craniectomy with Endoscopic Assistance.

Background Meckel's cave involvement in tumors pose a challenge due to their surrounding neurovascular structure and deep location. Case Review A 24-year-old male presented with progressive headaches and right sided trigeminal neuralgia with a large epidermoid. The tumor extended from the ambient cistern to the cerebellomedullary cistern and involved Meckel's cave ( Fig. 1 ). Technical Note/Video Description A retrosigmoid craniectomy was performed. Cranial nerves 3, 4, 6, 7, and 10, and auditory brainstem responses were monitored. Once the craniectomy was completed the dura was opened and cerebrospinal fluid (CSF) was released from the cisterna magna to allow for the tumor resection to be done without the use of any retractors ( Fig. 2 ). Care was taken to ensure that cranial nerves in the posterior fossa were detethered to prevent any traction injury. Using ring curettes the pearly white epidermoid tumor was able to be debulked. After all the possible tumor was resected with the microscope, the 30-degree endoscope was used to identify the porus trigeminus. Malleable ring curettes and a malleable suction were used to remove the soft tumor from this location. The patient transiently had loss of hearing but this returned within 2 weeks after surgery. Conclusions The retrosigmoid approach is familiar to all neurosurgeons and with the adjunct of an angled endoscope, the posterior Meckel's cave can be easily reached. This is particularly useful for tumors with soft consistency. The assistance of the endoscope allows Meckel's cave visualization without additional drilling while still allowing safe resection of tumor from around the trigeminal nerve. The link to the video can be found at: https://youtu.be/01aqOyUmSW0 .

Cranioplasty Using Polymethylmethacrylate Cement Following Retrosigmoid Craniectomy Decreases the Rate of Cerebrospinal Fluid Leak and Pseudomeningocele.

Cerebrospinal fluid (CSF) leak frequently occurs after retrosigmoid craniectomy. The present study investigated the effects of cranioplasty using polymethylmethacrylate (PMMA) cement to reduce the incidence of CSF leak following retrosigmoid craniectomy as compared with the autologous bone flap combined with titanium plates. Two hundred forty-three patients underwent surgeries via retrosigmoid approach for microvascular decompression or tumor resection. Of these, 107 patients underwent craniotomy, and incomplete cranioplasty was performed with autologous bone flap fixed with titanium plates, while 136 patients underwent craniectomy and complete cranioplasty was performed with PMMA cement. Variables including the incidence of CSF leak, pseudomeningocele formation, wound infection, rejection reaction were compared retrospectively based on the clinical data between the 2 groups. In the autologous bone group, 9 patients had postoperative CSF leaks, and 11 patients had pseudomeningoceles, while 3 CSF leaks and 2 pseudomeningoceles were found in the PMMA group. Statistical analysis showed that PMMA significantly decreased the incidence of postoperative CSF leaks (P = 0.03) and pseudomeningocele formation (P = 0.002). Wound infections were observed in 2 and 1 patients between the autologous bone and PMMA group, respectively, which did not differ significantly (P = 0.58). None of the patients in both groups developed a rejection reaction of artificial materials. Complete cranioplasty with PMMA cement following retrosigmoid craniectomy could decrease the incidence of CSF leak and pseudomeningocele formation as compared with the autologous bone flap combined with titanium plates. Thus, PMMA cement is preferable for bone reconstruction with excellent biocompatibility and without increasing the rate of wound infection.

Retrosigmoid Craniectomy for Resection of Epidermoid causing Trigeminal Neuralgia.

The differential diagnosis for trigeminal neuralgia like-symptoms includes cerebellopontine angle lesions causing regional mass effect upon the trigeminal nerve ( Fig. 1 ). Here we present an operative video manuscript of a patient experiencing trigeminal neuralgia, secondary to an epidermoid cyst, in which a retrosigmoid craniectomy was performed to resect the epidermoid and decompress the trigeminal nerve ( Fig. 2 ). This video highlights the operative nuances to achieving a successful surgery, including appropriate patient positioning, dural exposure to the transverse-sigmoid sinus junction, arachnoid dissection, and decompression of cranial nerves. A gross total resection was achieved; the patient reported immediate relief of facial pain postoperatively and has been pain free at the ten month follow-up. The link to the video can be found at: https://youtu.be/Ja2eE0uGk4E .

Microvascular Decompression for Geniculate Neuralgia through a Retrosigmoid Approach.

Objectives To describe a retrosigmoid approach for the microvascular sectioning of the nervus intermedius and decompression of the 5th and 9th cranial nerves, with emphasis on microsurgical anatomy and technique. Design A retrosigmoid craniectomy is performed in the lateral decubitus position. The dura is opened and cerebrospinal fluid (CSF) is released from the cisterna magna and cerebellopontine cistern. Dynamic retraction without rigid retractors is performed. Subarachnoid dissection of the cerebellopontine angle exposes the 7th to 8th nerve complex. A neuromonitoring probe is used with careful inspection of the microsurgical anatomy to identify the facial nerve and the nervus intermedius as they enter the internal auditory meatus. The nervus intermedius is severed. A large vein coursing superiorly across cranial 9th nerve was coagulated and cut. A Teflon pledget is inserted between a small vessel and the 5th nerve. Photographs of the region are borrowed from Dr. Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The senior author performed the surgery. The video was edited by Drs. V.N. and J.B. Outcome Measures Outcome was assessed by postoperative neurological function. Results The nervus intermedius was successfully cut and the 5th and 9th nerves were decompressed. The patient's pain resolved after surgery and at later follow-up. Conclusions Understanding the microsurgical anatomy of the cerebellopontine angle is necessary to identify the cranial nerves involved in facial pain syndromes. Subarachnoid dissection and meticulous microsurgical techniques are key elements for a successful microvascular decompression. The link to the video can be found at: https://youtu.be/pV5Wip7WusE .

Retrosigmoid Craniectomy for Vestibular Schwannoma with Hearing Preservation.

Objectives To describe a retrosigmoid craniectomy, hearing-preservation approach for resection of vestibular schwannoma. Design/Setting/Participants A video of a single patient undergoing the above approach at a tertiary care skull base surgery program. Results This video demonstrates a retrosigmoid craniectomy approach for resection of an enlarging intracanalicular vestibular schwannoma in a patient with normal hearing. The video highlights the pertinent surgical anatomy and outlines in a step-by-step fashion the surgical steps. The patient obtained a gross total resection with preservation of hearing. Conclusion A retrosigmoid craniectomy approach for vestibular schwannoma offers a potentially hearing preservation approach for selected tumors. The link to the video can be found at: https://youtu.be/VM663XztRZw .

Retractorless Retrosigmoid Craniectomy with Endoscopic Assistance to Meckel’s Cave, Technical Video

Retractorless Retrosigmoid Craniectomy with Endoscopic Assistance to Meckel’s Cave, Technical Video

Solitary fibrous tumor of the cerebellopontine angle: A case report and literature review

Solitary fibrous tumors (SFT) are rare dura-based mesenchymal tumors of the central nervous system. SFT occurring in the cerebellopontine (CP) angle is very rare and only 21 cases have been reported in the literature until date. We present a 40-year-old male patient who presented with features of the right-sided facial and acoustic nerves paresis along with same sided cerebellar symptoms of 2 months duration. Magnetic resonance imaging revealed a T2 heterogeneously hyperintense extra-axial lesion, showing intense contrast enhancement in the right CP angle with solid and cystic areas. The lesion was not extending into the internal auditory canal. Digital subtraction angiography showed arterial feeders from vertebro-basilar system. The highly vascular lesion was excised near-totally by suboccipital retrosigmoid craniectomy. The lesion was diagnosed as SFT on histopathological examination and was positive for CD34 and bcl-2.

Hydroxyapatite bone cement application for the reconstruction of retrosigmoid craniectomy in the treatment of cranial nerves disorders.

Background:Retromastoid craniectomy (RSC) is a cardinal surgical approach used to access the posterior fossa. Hydroxyapetite bone cement (HBC) is frequently employed for cranioplasty in efforts to prevent cerebrospinal fluid (CSF) leak, whilst maintaining low complication rates and good cosmetic satisfaction. The authors aim to determine the safety and effectiveness of HBC for reconstruction RSC used for treatment of various cranial nerves disorders.Methods:The authors conducted a retrospective one-center two surgeons review of 113 patients who underwent RSC filled with HBC for the treatment of cranial nerve disorders. The study period extended from January 2011 through April 2016. Charts were reviewed for documentation of descriptors pertinent to the endpoints described above. Revisions and reoperations were excluded from analysis.Results:Ninety-three patients met the inclusion criteria; there was one case of postoperative pseudomeningocele, which was considered as CSF leak (1%), 3 (3,2%) superficial infections, and no deep infections. Cosmetic satisfaction was obtained in all but one case (98.9% satisfaction) and long-term incisional pain was problematic in 1 (1.1%) patient. Other complications (serous drainage, headache, ear pain) accounted for three cases (3.2%).Conclusions:The application of HBC in the reconstruction of RSC for the treatment of cranial nerves disorders is an effective method, yielding good cosmetic results whilst eliminating CSF leak. Additionally, it is safe due to the lack of deep-seated wound infections with low incidence of chronic incisional pain.

Intrapetrous Internal Carotid Artery: Evaluation of Exposure, Mobilization and Surgical Maneuvers Feasibility from a Retrosigmoid Approach in a Cadaveric Model

To provide a quantification of the exposure of the vertical and horizontal segments of the intrapetrous carotid artery (IPCA) and to evaluate the possibilities of its mobilization and of performing surgical maneuvers on it using the retrosigmoid approach. Twelve surgical dissections were performed bilaterally on 6 fresh cadavers. Predissection computed tomography (CT) scans with bone fiducials for intraoperative navigation were acquired. A retrosigmoid craniectomy was performed. The inframeatal space was drilled, the horizontal (HoIPCA) and vertical (VeIPCA) segments of the IPCA were exposed, and their measurements were recorded. The carotid canal was enlarged, the artery was carefully detached from the bone, and a vessel loop was inserted in order to mobilize its horizontal segment. Afterwards we performed different surgical maneuvers: We inflated a 5-French Fogarty balloon to compress the IPCA and repaired a 7-mm arteriotomy with a running suture. Specimens underwent a new CT scan to evaluate the amount of bone removal and the integrity of the inner ear structures. The HoIPCA and VeIPCA were exposed andanatomically preserved in all specimens without injuring the surrounding neurovascular structures. The HoIPCA presented an average length of 24.89 mm (range:19.41-31.47 mm), and the VeIPCA presented an average length of 10.07 mm (range: 8.92-11.58 mm). The possibility of IPCA mobilization and the feasibility of performing surgical maneuvers were demonstrated. Postdissection CT scan showed the preservation of inner ear structures. Exposure and mobilization of the IPCA using a retrosigmoid approach are feasible and could represent a viable option for the possibility of reaching a total resection of selected skull base tumors, even when involvement of the carotid canal is present.