Far-lateral Transcondylar Approach Research Articles

Endoscope-assisted far-lateral transcondylar approach for craniocervical junction chordomas: a retrospective case series and cadaveric dissection.

Craniocervical junction (CCJ) chordomas are a neurosurgical challenge because of their deep localization, lateral extension, bone destruction, and tight relationship with the vertebral artery and lower cranial nerves. In this study, the authors present their surgical experience with the endoscope-assisted far-lateral transcondylar approach (EA-FLTA) for the treatment of CCJ chordomas, highlighting the advantages of this corridor and the integration of the endoscope to reach the anterior aspect and contralateral side of the CCJ and the possibility of performing occipitocervical fusion (OCF) during the same stage of surgery. Nine consecutive cases of CCJ chordomas treated with the EA-FLTA between 2013 and 2020 were retrospectively reviewed. Preoperative characteristics, surgical technique, postoperative results, and clinical outcome were analyzed. A cadaveric dissection was also performed to clarify the anatomical landmarks. The male/female ratio was 1.25, and the median age was 36 years (range 14-53 years). In 6 patients (66.7%), the lesion showed a bilateral extension, and 7 patients (77.8%) had an intradural extension. The vertebral artery was encased in 5 patients. Gross-total resection was achieved in 5 patients (55.6%), near-total resection in 3 (33.3%), and subtotal resection 1 (11.1%). In 5 cases, the OCF was performed in the same stage after tumor removal. Neither approach-related complications nor complications related to tumor resection occurred. During follow-up (median 18 months, range 5-48 months), 1 patient, who had already undergone treatment and radiotherapy at another institution and had an aggressive tumor (Ki-67 index of 20%), showed tumor recurrence at 12 months. The EA-FLTA provides a safe and effective corridor to resect extensive and complex CCJ chordomas, allowing the surgeon to reach the anterior, lateral, and posterior portions of the tumor, and to treat CCJ instability in a single stage.

The Glossopharyngo-Cochlear Triangle-Part II: Case Series Highlighting the Clinical Application to High-Riding Posterior Inferior Cerebellar Artery Aneurysms Exposed Through the Extended Retrosigmoid Approach.

Use of the far lateral transcondylar (FL) approach and vagoaccessory triangle is the standard exposure for clipping most posterior inferior cerebellar artery (PICA) aneurysms. However, a distal PICA origin or high-lying vertebrobasilar junction can position the aneurysm beyond the vagoaccessory triangle, making the conventional FL approach inappropriate. To demonstrate the utility of the extended retrosigmoid (eRS) approach and a lateral trajectory through the glossopharyngo-cochlear triangle as the surgical corridor for these cases. High-riding PICA aneurysms treated by microsurgery were retrospectively reviewed, comparing exposure through the eRS and FL approaches. Clinical, surgical, and outcome measures were evaluated. Distances from the aneurysm neck to the internal auditory canal (IAC), jugular foramen, and foramen magnum were measured. Six patients with PICA aneurysms underwent clipping using the eRS approach; 5 had high-riding PICA aneurysms based on measurements from preoperative computed tomography angiography (CTA). Mean distances of the aneurysm neck above the foramen magnum, below the IAC, and above the jugular foramen were 27.0 mm, 3.7 mm, and 8.2 mm, respectively. Distances were all significantly lower versus the comparison group of 9 patients with normal or low-riding PICA aneurysms treated using an FL approach (P<.01). All 6 aneurysms treated using eRS were completely occluded without operative complications. The eRS approach is an important alternative to the FL approach for high-riding PICA aneurysms, identified as having necks more than 23 mm above the foramen magnum on CTA. The glossopharyngo-cochlear triangle is another important anatomic triangle that facilitates microsurgical dissection.

Far-Lateral Transcondylar Approach to a Right Cervicomedullary Dural Arteriovenous Fistula of the Posterior Fossa.

Objectives Dural arteriovenous fistulas (DAVFs) at the cervicomedullary junction are uncommon and often accompanied by subarachnoid hemorrhage (SAH). We aim to illustrate in detail the microsurgical procedure for treating a DAVF located at the cervicomedullary junction. Design We present a two-dimensional operative video that includes clinical history, preoperative imaging, surgical strategy, still images with labels, clinical course, and postoperative imaging. Setting The microsurgery was performed at an academic medical center. Participant The patient is a 55-year-old female who presented with SAH, acute onset headache, nausea, and vomiting. Angiography demonstrated right vertebral artery vasospasm and a persistent arteriovenous shunt at the cervicomedullary junction supplied by small perforating arteries of the right vertebrobasilar junction ( Fig. 1 ). Main Outcome Measures The patient was placed in the park-bench position with the head turned to the contralateral side. A hockey stick incision was made, followed by a right-side far-lateral transcondylar approach. Indocynanine green videoangiography was performed to help identify the areas of arteriovenous shunting. Multiple clips were placed to interrupt vessels that corresponded to arterial feeders at the level of the C1 and C2 nerve root sleeves ( Fig. 2 ). The dura was closed in a water tight fashion and the posterior fossa was reconstructed with a titanium mesh. Results Postoperative imaging showed no evidence of continued arteriovenous shunting. The patient was discharged in good clinical condition with an uneventful postoperative course. Conclusion A deep understanding of the microsurgical vascular anatomy is necessary for successful occlusion of a cervicomedullary DAVF. The link to the video can be found at: https://youtu.be/-LfOcNB05BY .

Far Lateral Transcondylar Approach for Anterior Foramen Magnum Lesions

Objective: To study the efficacy and safety of far-lateral transcondylar approach for anterior foramen magnum lesions with early experience at our Institute.&#x0D; Material and Methods: We treated six patients, with lesion anterior to the foramen magnum and posterior to the brainstem and cervical cord in a period of 2 years, March 2017 to March 2018.Initial assessment was made by history and examination followed by CT scan and contrast MRI. All were treated using far-lateral transcondylar approach.&#x0D; Result: Among six patients, there were two were male and four were female. Three of these patients had a meningioma while two patients had neurofibromas and one clival chordoma. Total excision was achieved in five neoplastic cases, while subtotal excision was done in one case. There were no fresh postoperative deficits in any of the other patients. One patient had an unexplained sudden cardiorespiratory arrest 18h after the surgery and succumbed. One patient had cerebrospinal fluid (CSF) discharge from the wound, which was satisfactorily managed by lumber CSF drainage.&#x0D; Conclusion: This approach provides an excellent approach to lesions located anterior to foramen magnum posterior to the brainstem and upper cervical cord. Gross total excision of these benign and malignant lesions is safely possible through this approach.&#x0D; Keywords: Craniovertebral Junction, Far-Lateral Transcondylar Approach, Anterior Foramen Magnum, Brain Stem, Chordoma.

Aggressive, Multidisciplinary Staged Microsurgical Resection of a Giant Cervicomedullary Junction Chordoma.

Chordomas of the cranial base are locally destructive tumors since they are surrounded by significant complex neurovascular structures. Thus, their surgical removal is challenging, recurrence rates are high, and their therapeutic strategies remain controversial.In this video, we present a 47-year-old man with a recent onset of swallowing difficulties, hoarseness, and weight loss for several weeks. In the neurological examination, he had complete paralysis of the 9th, 10th, 11th, and 12th cranial nerves. Magnetic resonance imaging (MRI) showed a heterogeneously enhancing expansile invasive mass lesion centered within the clivus and involving the C1, the occipitocervical junction, the retropharynx, and the hypoglossal canal. The decision was made to proceed with multiple staged surgeries. In the first surgical stage, we performed a mastoidectomy with the infralabyrinthine approach to perform a test clip ligation of the sigmoid sinus and to resect the tumor component that extended into the infralabyrinthine space. In the second stage, we performed a far-lateral transcondylar approach for tumor resection and occipitocervical fusion. In the third stage, we used a transoral approach with endoscopic assistance to complete the excision of the remaining tumor in the retropharyngeal space and anterior aspect of C1 and C2 bodies that were not accessible in the first two stages.The surgeries and postoperative course were uneventful. Postoperative MRI showed a gross total resection of the tumor. Histopathology indicated a chordoma. The patient subsequently received proton radiotherapy and has continued to do well without recurrence at 14 months' follow-up. The link to the video can be found at: https://youtu.be/uP9OSlKg_rE .

Far-lateral Transcondylar Approach to Anterior Foramen Magnum Lesions - Our Experience.

Background:Initial surgical management of the anterior foramen magnum lesions through the posterior approaches was fraught with unacceptable morbidity, mortality, and incomplete removal. The far-lateral approach provides excellent exposure and access to these lesions resulting in complete excision of these lesions with reduced frequency of unwanted complications.Materials and Methods:Eight patients with lesions anterior to the brainstem and upper cervical cord were surgically treated using the far-lateral transcondylar approach. Two of these patients had a meningioma while three patients had “white epidermoid.” One patient had a vertebral artery (VA) aneurysm while another was a rare case of lower brainstem compression by the VA and the last was a clival chordoma. The technical aspects of this surgical procedure are briefly illustrated in this article.Results:Total excision was achieved in five neoplastic cases while subtotal excision was done in one case. The VA aneurysm was satisfactorily clipped while in the brainstem compression patient, microvascular decompression was done. The VA aneurysm patient developed postoperative lower cranial nerve palsies. There were no fresh postoperative deficits in any of the other patients. One patient had an unexplained sudden cardiorespiratory arrest 18 h after the surgery and succumbed. One patient had cerebrospinal fluid (CSF) otorrhea which was satisfactorily managed by intrathecal CSF drainage.Conclusion:The far-lateral transcondylar approach provides excellent approach to lesions located anterior to the brainstem and upper cervical cord. Total excision of these benign lesions is safely possible through this approach.

How I do it: surgical clipping of vertebrobasilar junction aneurysms through a far-lateral transcondylar approach

Vertebrobasilar junction aneurysms occur rarely, but have a higher rupture rate than supratentoral aneurysms, and higher morbidity and mortality. Their location ventral to the neuroaxis makes them a challenging surgical lesion. In this paper, we share our experience with the surgical technique for the management of these complex aneurysms. An in-depth understanding of the anatomy of these aneurysms, careful preoperative planning, and a meticulous surgical technique, including knowledge of every detail of the procedure-positioning, an advanced skull base technique, and careful aneurysm dissection and clipping-is essential for a successful outcome of the surgery.

Occipitocervical Instability After Far-Lateral Transcondylar Surgery: A Biomechanical Analysis.

After a far-lateral transcondylar approach, patients may maintain neutral alignment in the immediate postoperative period, but severe occipitoatlantal subluxation may occur gradually with cranial settling and possible neurological injury. Previous research is based on assumptions regarding the extent of condylar resection and the change in biomechanics that produces instability. To quantify the extent of bone removal during a far-lateral transcondylar approach, determine the changes in range of motion (ROM) and stiffness that occur after condylar resection, and identify the threshold of condylar resection that predicts alterations in occipitocervical biomechanics. Nine human cadaveric specimens were biomechanically tested before and after far-lateral transcondylar resection extending into the hypoglossal canal (HC). The extent of condylar resection was quantified using volumetric comparison between pre- and postresection computed tomography scans. ROM and stiffness testing were performed in intact and resected states. The extent of resection that produced alterations in occipitocervical biomechanics was assessed with sensitivity analysis. Bone removal during condylar resection into the HC was 15.4%-63.7% (mean 35.7%). Sensitivity analysis demonstrated that changes in biomechanics may occur when just 29% of the occipital condyle was resected (area under the curve 0.80-1.00). Changes in occipitocervical biomechanics may be observed if one-third of the occipital condyle is resected. During surgery, the HC may not be a reliable landmark to guide the extent of resection. Patients who undergo condylar resections extending into or beyond the HC require close surveillance for occipitocervical instability.

Using a modified far-lateral approach to remove hypoglossal neurilemmomas: notes on technique

In this paper the authors describe a modified far-lateral transcondylar approach to remove hypoglossal neurilemmomas (HGNs). Between September 2008 and June 2011, 11 consecutive patients with HGNs underwent tumor removal via a modified far-lateral transcondylar approach. The average age at presentation, tumor characteristics, cranial nerve (CN) deficits, and outcomes were assessed. The modified far-lateral transcondylar approach comprises several important steps. The first step is to remove the limited posterior aspect of the condylar facet to open the hypoglossal canal. The second step is to expose the posterior arch and the transverse process of C-1. A fat layer covers the venous plexus of the vertebral artery, and careful dissection along this surface of the fat layer is important to protect the vertebral artery from damage. The neck muscles are dissected caudally to expose the extracranial component of the tumor, which is located in front of the transverse process of C-1. Eleven cases of HGNs were treated during the study period. The mean patient age was 47.4 ± 8.9 years (range 31-59 years); there were 3 men and 8 women. The mean follow-up period was 14.1 ± 9 months. All patients presented with hypoglossal nerve deficits; other commonly observed deficits included glossopharyngeal and vestibular/cochlear nerve deficits. Gross-total resection of the tumor was achieved in 10 patients. A subtotal resection of the tumor was achieved in the remaining patient. Two patients had transient postoperative facial nerve palsies, 1 patient developed a new CN XI palsy postoperatively, and 5 patients experienced transient hoarseness and difficulty swallowing. Two patients required a tracheotomy because they demonstrated dysfunction of the caudal CNs and subsequently developed postoperative pneumonia. Postoperatively, 5 patients required the temporary placement of a nasogastric feeding tube. There were no surgery-related deaths in this series. The modified far-lateral transcondylar approach is an effective treatment for HGNs, yielding a high total tumor removal rate with an acceptable rate of morbidity.

Microsurgical Excision of the Craniocervical Neurenteric Cysts by the Far-Lateral Transcondylar Approach: Case Report and Review of the Literature

Neurenteric cysts in the anterior craniocervical junction (CCJ) region can be found in extremely rare cases. We report one case with craniocervical neurenteric cyst that was excised by the far-lateral transcondylar (FLT) approach. A 43-year-old man presented with a history of recurrent episodes of mild neck pain and dysesthesia in his bilateral hands of 2 years' duration with rapid deterioration 3 weeks prior to admission. Magnetic resonance imaging (MRI) of the CCJ region revealed a well-defined intradural cystic lesion located ventral from the pontomedullary junction to C1 vertebra with medulla and C1 cord compression. This patient underwent total excision of the lesion via the FLT approach without any postoperative neurological deficits, and the histopathologic diagnosis was neurenteric cyst. Follow-up MRI has revealed no evidence of recurrence. The clinical features, imaging studies, and surgical approach options involved in resecting craniocervical neurenteric cysts are discussed, along with a review of the literature.

Microsurgical treatment of foramen magnum meningiomas

Objective To report the clinical and radiological features as well as the surgical findings and outcomes for foramen magnum meningiomas (FFM) patients treated in the department of neurosurgery in Beijing Tiantan hospital over the last 15 years. Methods 114 consecutive cases of FFM operated between May 1993 and June 2008 were reviewed and followed up. Results Cervieo-occipital pain (80.7%), headache and dizziness (42.1%) were the most common symptoms. The mean duration of preoperative process was 11.7 months. The preoperative KPS was 72.5±8.3.All the FFMs were classified as anterior (80 cases), anterolateral (24 cases) and posterolateral (10 cases) types. The mean maximum diameter of tumors on MRI was (3.35±5.6)cm.The posterior midline approach was performed in 10 cases, far-lateral transcondylar or retrocondylar approach in 97 cases and extended far-lateral approach in 7 cases.Gross total resection was achieved in 86.0% of patients, and subtotal resection in 14.0%.Surgical mortality was 1.8%.Follow-up data were available for 93 patients, with a mean follow-up duration of 90.3 months (from 1 to 180 months). 59 (63.4%) patients lived a normal life (KPS, 80～100).Conclusions Most anterior and anteriolateral FFMs can be completely resected by far-lateral transcondylar or retrocondylar approach. Total removal of tumors should be attempted to achieved at the first operation. Postoperative management of FFM is important for prognosis. Key words: Foramen magnum; Meningioma; Microsurgery; Prognosis

Microsurgical anatomy of the posterior spinal artery via a far-lateral transcondylar approach

The posterior spinal artery (PSA) is a clinically significant vessel that may frequently be encountered during the far-lateral transcondylar approach. There have been a limited number of reports on the specific origin of the PSA in the literature. The aim of this study was to demonstrate the origin of the PSA. Thirteen cadaveric heads (26 sides) were injected with colored silicon. A bilateral far-lateral transcondylar approach was performed on each side. In every specimen the site of the origin of the PSAs, as well as their course, branching pattern and anastomoses, external diameters, and neighboring vascular and nervous structures were recorded. Microanatomical dissections were performed using the surgical microscope. In addition, 8 surgical cases in which the far-lateral approach was used were collected prospectively to record the course and origin of the PSA. Altogether, a total of 34 sides were analyzed for their PSA origin and course. In the cadaveric specimens, the PSA was found to originate from the vertebral artery (VA) in 25 sides (96%). In 13 specimens (50%) the PSA originated from the V(4) segment of the VA intradurally. In 12 specimens (46%) the PSA originated from the V(3) segment of the VA extradurally. In 1 specimen (4%), in whom the posterior inferior cerebellar artery (PICA) had an early origin from the VA extradurally at the C-1 level, the PSA originated from the PICA. Of the 8 surgical cases, 2 patients had extradural origin of the PSA from the V(3) segment of the VA, whereas 6 patients had intradural origin of the PSA from the V(4) segment. Although the usual origin of the PSA is from the VA either intra- or extradurally, its origin is closely related to the origin of the PICA. The PSA originates from the PICA in cases in which the PICA originates extradurally from the VA. In the far-lateral transcondylar approach, the dura is opened in close proximity to the VA. Knowledge of the origin and course of the PSA is critically important when executing the far-lateral approach to avoid its injury.

Microsurgical Anatomy of the Posterior Spinal Artery

Objectives: The goal of this study was to demonstrate the origin of the posterior spinal artery and its anatomical relationship to the other structures of the posterior fossa. This artery may be frequently encountered during the far-lateral transcondylar approach to the anterior portion of the posterior fossa. To our knowledge, there have been no previous microanatomic studies delineating the specific origin of the posterior spinal artery. Knowledge of this anatomy may provide for safer dural opening during the far-lateral approach and lesser incidence of posterior spinal artery syndrome.

Dural arteriovenous fistula of the anterior condylar confluence and hypoglossal canal mimicking a jugular foramen tumor

The anterior condylar confluence (ACC) is located on the external orifice of the canal of the hypoglossal nerve and provides multiple connections with the dural venous sinuses of the posterior fossa, internal jugular vein, and the vertebral venous plexus. Dural arteriovenous fistulas (DAVFs) of the ACC and hypoglossal canal (anterior condylar vein) are extremely rare. The authors present a case involving an ACC DAVF and hypoglossal canal that mimicked a hypervascular jugular bulb tumor. This 53-year-old man presented with right hypoglossal nerve palsy. A right pulsatile tinnitus had resolved several months previously. Magnetic resonance imaging demonstrated an enhancing right-sided jugular foramen lesion involving the hypoglossal canal. Cerebral angiography revealed a hypervascular lesion at the jugular bulb, with early venous drainage into the extracranial vertebral venous plexus. This was thought to represent either a glomus jugulare tumor or a DAVF. The patient underwent preoperative transarterial embolization followed by surgical exploration via a far-lateral transcondylar approach. At surgery, a DAVF was identified draining into the ACC and hypoglossal canal. The fistula was surgically obliterated, and this was confirmed on postoperative angiography. The patient's hypoglossal nerve palsy resolved. Dural arteriovenous fistulas of the ACC and hypoglossal canal are rare lesions that can present with isolated hypoglossal nerve palsies. They should be included in the differential diagnosis of hypervascular jugular bulb lesions. The authors review the anatomy of the ACC and discuss the literature on DAVFs involving the hypoglossal canal.

Far-lateral transcondylar approach: surgical technique and its application in neurenteric cysts of the cervicomedullary junction

Neurenteric cysts are rare benign lesions of the central nervous system that are lined by endodermal cell-derived epithelium. Although they occur mostly in the spine, they can occur intracranially, most often in the posterior fossa. Neurenteric cysts that are located in the anterior cervicomedullary junction are even rarer and often require a skull base approach for adequate resection. The authors describe two cases of neurenteric cysts arising from the cervicomedullary junction that were resected via a far-lateral transcondylar approach. They discuss the surgical approach and operative nuances involved in removing these lesions, and review the clinical presentation of neurenteric cysts in this region as well as the neuroimaging characteristics, histopathological findings, and surgical management. Intraoperative videos are presented.

Endoscope-assisted far-lateral transcondylar approach to the skull base.

The far-lateral transcondylar approach was used in this cadaveric study in an attempt to evaluate the usefulness of endoscope-assisted microsurgery in this region of the skull base. The study was carried out using 4 latex-injected, formalin-fixed cadaver heads. After initial examination of intradural structures under an operating microscope, a zero degree 4 mm diameter solid-rod endoscope lens was introduced and guided into position under the direction of the operating microscope. Photographs of the regional anatomy were taken through this lens and through a 30 degree angled lens and compared to photographs of the anatomy taken through the microscope. Clear close-up views of the dural portals and intradural course of the cranial nerves were obtained using the endoscope. The endoscope was introduced through three corridors enclosed with cranial nerves, providing the surgeon with panoramic views of the vertebrobasilar arteries and anterior brainstem surface. The endoscope can be guided through narrow corridors and placed immediately adjacent to a region of interest at the skull base. It enables the surgeon to look around blind corners and work behind structures that are hidden from microscopic view.

The transcondylar approach

The transcondylar approach is a skull-base technique that enables neurosurgeons to access the anterior brain stem and foramen magnum region with minimum retraction. This extension of the unilateral suboccipital approach optimizes the surgical treatment of lesions in this region, including benign tumors, bony and locally invasive tumors, and vascular lesions. Many variations of the lateral skull-base approach to the anterior craniovertebral junction, which include variable resection of the condyle, have been published. This article summarizes some of these variations and describes the far-lateral transcondylar approach as performed at our institution. It also reviews the indications, advantages, and disadvantages of the approach.

Glossopharyngeal Nerve Schwannoma: Report of a Case Operated on by the Far-Lateral Transcondylar Approach

Complete resection with conservation of cranial nerves is the primary goal of contemporary surgery for lower cranial nerve tumors. We describe the case of a patient with a schwannoma of the left glossopharyngeal nerve, operated on in our Neurosurgical Unit. The far lateral approach combined with laminectomy of the posterior arch of C1 was done in two steps. The procedure allowed total tumor resection and was found to be better than classic unilateral suboccipital or combined supra- and infratentorial approaches. The advantages and disadvantages of the far lateral transcondylar approach, compared to the other more common approaches, are discussed.