scholarly journals Biomechanical evaluation of the craniovertebral junction after unilateral joint-sparing condylectomy: implications for the far lateral approach revisited

2017 ◽  
Vol 127 (4) ◽  
pp. 829-836 ◽  
Author(s):  
Varun R. Kshettry ◽  
Andrew T. Healy ◽  
Robb Colbrunn ◽  
Dylan T. Beckler ◽  
Edward C. Benzel ◽  
...  
Keyword(s):  
Axial Rotation ◽  
Craniovertebral Junction ◽  
Foramen Magnum ◽  
Lateral Approach ◽  
Occipital Condyle ◽  
Intact State ◽  
Flexion Extension ◽  
Far Lateral Approach ◽  
Far Lateral

OBJECTIVEThe far lateral transcondylar approach to the ventral foramen magnum requires partial resection of the occipital condyle. Early biomechanical studies suggest that occipitocervical (OC) fusion should be considered if 50% of the condyle is resected. In clinical practice, however, a joint-sparing condylectomy has often been employed without the need for OC fusion. The biomechanics of the joint-sparing technique have not been reported. Authors of the present study hypothesized that the clinically relevant joint-sparing condylectomy would result in added stability of the craniovertebral junction as compared with earlier reports.METHODSMultidirectional in vitro flexibility tests were performed using a robotic spine-testing system on 7 fresh cadaveric spines to assess the effect of sequential unilateral joint-sparing condylectomy (25%, 50%, 75%, 100%) in comparison with the intact state by using cardinal direction and coupled moments combined with a simulated head weight “follower load.”RESULTSThe percent change in range of motion following sequential condylectomy as compared with the intact state was 5.2%, 8.1%, 12.0%, and 27.5% in flexion-extension (FE); 8.4%, 14.7%, 39.1%, and 80.2% in lateral bending (LB); and 24.4%, 31.5%, 49.9%, and 141.1% in axial rotation (AR). Only values at 100% condylectomy were statistically significant (p < 0.05). With coupled motions, however, −3.9%, 6.6%, 35.8%, and 142.4% increases in AR+F and 27.3%, 32.7%, 77.5%, and 175.5% increases in AR+E were found. Values for 75% and 100% condyle resection were statistically significant in AR+E.CONCLUSIONSWhen tested in the traditional cardinal directions, a 50% joint-sparing condylectomy did not significantly increase motion. However, removing 75% of the condyle may necessitate fusion, as a statistically significant increase in motion was found when E was coupled with AR. Clinical correlation is ultimately needed to determine the need for OC fusion.

scholarly journals The far-lateral approach: destruction of the condyle does not necessarily result in clinically evident craniovertebral junction instability

2016 ◽  
Vol 125 (1) ◽  
pp. 196-201 ◽  
Author(s):  
Ehab Shiban ◽  
Elisabeth Török ◽  
Maria Wostrack ◽  
Bernhard Meyer ◽  
Jens Lehmberg
Keyword(s):  
Extent Of Resection ◽  
Craniovertebral Junction ◽  
Foramen Magnum ◽  
Lateral Approach ◽  
Occipitocervical Fusion ◽  
Anterior Portion ◽  
Far Lateral Approach ◽  
Clinical Instability ◽  
Craniocervical Instability ◽  
Far Lateral

OBJECT Far-lateral or extreme-lateral approaches to the skull base allow access to the lateral and anterior portion of the lower posterior fossa and foramen magnum. These approaches include a certain extent of resection of the condyle, which potentially results in craniocervical junction instability. However, it is debated what extent of condyle resection is safe and at what extent of condyle resection an occipitocervical fusion should be recommended. The authors reviewed cases of condyle resection/destruction with regard to necessity of occipitocervical fusion. METHODS The authors conducted a retrospective analysis of all patients in whom a far- or extreme-lateral approach including condyle resection of various extents was performed between January 2007 and December 2014. RESULTS Twenty-one consecutive patients who had undergone a unilateral far- or extreme-lateral approach including condyle resection were identified. There were 10 male and 11 female patients with a median age of 61 years (range 22–83 years). The extent of condyle resection was 25% or less in 15 cases, 50% in 1 case, and greater than 75% in 5 cases. None of the patients who underwent condyle resection of 50% or less was placed in a collar postoperatively or developed neck pain. Two of the patients with condyle resection of greater than 75% were placed in a semirigid collar for a period of 3 months postoperatively and remained free of pain after this period. At last follow-up none of the cases showed any clear sign of radiological or clinical instability. CONCLUSIONS The unilateral resection or destruction of the condyle does not necessarily result in craniocervical instability. No evident instability was encountered even in the 5 patients who underwent removal of more than 75% of the condyle. The far- or extreme-lateral approach may be safer than generally accepted with regard to craniocervical instability as generally considered and may not compel fusion in all cases with condylar resection of more than 75%.

Far Lateral Craniotomy Closure Technique for Preservation of Suboccipital Musculature

2020 ◽  
Author(s):  
Muhammad Salman Ali ◽  
Stephen T. Magill ◽  
Michael W. McDermott
Keyword(s):  
Muscle Atrophy ◽  
Craniovertebral Junction ◽  
Contralateral Side ◽  
Lateral Approach ◽  
Senior Author ◽  
Occipital Condyle ◽  
Closure Technique ◽  
Far Lateral Approach ◽  
Far Lateral ◽  
Initial Results

AbstractThe far lateral approach is used for accessing pathology at the craniovertebral junction but can be complicated by postoperative suboccipital muscle atrophy. In addition to significant cosmetic deformity, this atrophy can lead to head and neck pain and potentially could contribute to cranio-cervical instability. To address this issue, the senior author began using a single myocutaneous flap without a muscle cuff and securing it directly to the bone using predrilled holes in the bone that resemble a chevron. The method is described and illustrated with an example case. Results from seven consecutive cases are reported since the technique was adopted. Muscle atrophy was measured by calculating area at the level of the occipital condyle and compared with the contralateral side. No significant differences were noted. In conclusion, we have found this to be an excellent closure technique and wanted to present our initial results for consideration by other skull base surgeons.

Evaluating stability of the craniovertebral junction after unilateral C1 lateral mass resection: implications for the direct lateral approach

2021 ◽  
pp. 1-7
Author(s):  
Pranay Soni ◽  
Jeremy G. Loss ◽  
Callan M. Gillespie ◽  
Robb W. Colbrunn ◽  
Richard Schlenk ◽  
...  
Keyword(s):  
Axial Rotation ◽  
Craniovertebral Junction ◽  
Craniocervical Junction ◽  
Lateral Approach ◽  
Biomechanical Study ◽  
Lateral Mass ◽  
Internal Stabilization ◽  
Flexion Extension ◽  
Direct Lateral Approach

OBJECTIVE The direct lateral approach is an alternative to the transoral or endonasal approaches to ventral epidural lesions at the lower craniocervical junction. In this study, the authors performed, to their knowledge, the first in vitro biomechanical evaluation of the craniovertebral junction after sequential unilateral C1 lateral mass resection. The authors hypothesized that partial resection of the lateral mass would not result in a significant increase in range of motion (ROM) and may not require internal stabilization. METHODS The authors performed multidirectional in vitro ROM testing using a robotic spine testing system on 8 fresh cadaveric specimens. We evaluated ROM in 3 primary movements (axial rotation [AR], flexion/extension [FE], and lateral bending [LB]) and 4 coupled movements (AR+E, AR+F, LB + left AR, and LB + right AR). Testing was performed in the intact state, after C1 hemilaminectomy, and after sequential 25%, 50%, 75%, and 100% C1 lateral mass resection. RESULTS There were no significant increases in occipital bone (Oc)–C1, C1–2, or Oc–C2 ROM after C1 hemilaminectomy and 25% lateral mass resection. After 50% resection, Oc–C1 AR ROM increased by 54.4% (p = 0.002), Oc LB ROM increased by 47.8% (p = 0.010), and Oc–C1 AR+E ROM increased by 65.8% (p < 0.001). Oc–C2 FE ROM increased by 7.2% (p = 0.016) after 50% resection; 75% and 100% lateral mass resection resulted in further increases in ROM. CONCLUSIONS In this cadaveric biomechanical study, the authors found that unilateral C1 hemilaminectomy and 25% resection of the C1 lateral mass did not result in significant biomechanical instability at the occipitocervical junction, and 50% resection led to significant increases in Oc–C2 ROM. This is the first biomechanical study of lateral mass resection, and future studies can serve to validate these findings.

scholarly journals Foramen Magnum Meningioma: Far Lateral Approach

2019 ◽  
Vol 80 (S 04) ◽  
pp. S363-S364
Author(s):  
Ciro Vasquez ◽  
Alexander Yang ◽  
A. Samy Youssef
Keyword(s):  
Vertebral Artery ◽  
Cranial Nerves ◽  
Mass Effect ◽  
Craniocervical Junction ◽  
Foramen Magnum ◽  
Lateral Approach ◽  
Neurological Deficits ◽  
Occipital Condyle ◽  
Far Lateral Approach ◽  
Far Lateral

We present a case of a foramen magnum meningioma in a 42-year-old female who presented with headaches for 2 years, associated with decreased sensation and overall feeling of “heaviness” of the right arm. The tumor posed significant mass effect on the brainstem, and given the location of the tumor in the anterolateral region of the foramen magnum, a right far lateral approach was chosen. The approach incorporates the interfascial dissection technique to safely expose and preserve the vertebral artery in the suboccipital triangle. After drilling the posteromedial portion of the occipital condyle and opening the dura, the tumor can be entirely exposed with minimal retraction on the cerebellum. The working space offered by the far lateral approach allows careful dissection at the lateral craniocervical junction, and preservation of the V4 segment of the vertebral artery and the lower cranial nerves. Simpson's grade-2 resection was achieved with coagulation of the dural base around the vertebral artery. The postoperative course was unremarkable for any neurological deficits. At the 2-year follow-up, imaging identified no recurrence of tumor and the patient remains asymptomatic.The link to the video can be found at: https://youtu.be/IMN1O7vO5B0.

scholarly journals Resection of Foramen Magnum Meningioma through Modified Far Lateral Approach: Surgical Principles and Technical Nuances

2020 ◽  
Author(s):  
Vinayak Narayan ◽  
Fareed Jumah ◽  
Anil Nanda
Keyword(s):  
Spinal Cord ◽  
Tumor Resection ◽  
Cranial Nerves ◽  
Surgical Techniques ◽  
Foramen Magnum ◽  
Lateral Approach ◽  
Occipital Condyle ◽  
Far Lateral Approach ◽  
Far Lateral ◽  
Neurovascular Structures

Abstract Objectives Safe maximal resection is the basic principle of cranial base surgery and the grade of resection is an important factor influencing the prognostic outcome. This operative video highlights the surgical principles and technical nuances in the microsurgical resection of foramen magnum meningioma (FMM). Case Description The surgery was performed in a 45-year-old lady who presented with hoarseness of voice and spastic quadriparesis (grade 4/5). On imaging, FMM with mass effect on brainstem and spinal cord was identified. The tumor was gross totally resected through modified far lateral approach with minimal occipital condyle drilling. This video demonstrates the surgical techniques of tumor resection including early devascularization, operating in the arachnoid plane to dissect the neurovascular structures, piecemeal decompression, sharp dissection to separate tumor from lower cranial nerves (LCN), identifying the brainstem veins, and resecting the lesion from tumor–brainstem interface. Postoperatively, she had significant neurological improvement and the magnetic resonance imaging revealed excellent radiological outcome (Figs. 1 and 2). Conclusion The surgery of FMM is challenging due to the deep surgical corridor, critical location, close proximity with various neurovascular structures, firm consistency, and high vascularity of the tumor. The modified far lateral approach by preserving the occipital condyle may prevent the postoperative incidence of craniovertebral junction instability. The key operative principles to achieve the best surgical outcome include careful dissection along the arachnoid plane, gentle handling of cranial nerves, veins, and perforator vessels, avoidance of traction on brainstem and spinal cord, intraoperative neurophysiological monitoring, proper hemostasis, and meticulous dural closure.The link to the video can be found at: https://youtu.be/1qvAeUmNIUw.

Far-lateral approach to intradural lesions of the foramen magnum without resection of the occipital condyle

2002 ◽  
Vol 96 (2) ◽  
pp. 302-309 ◽  
Author(s):  
Anil Nanda ◽  
David A. Vincent ◽  
Prasad S. S. V. Vannemreddy ◽  
Mustafa K. Baskaya ◽  
Amitabha Chanda
Keyword(s):  
Craniocervical Junction ◽  
Foramen Magnum ◽  
Lateral Approach ◽  
Additional Patient ◽  
Occipital Condyle ◽  
Rheumatoid Disease ◽  
Content Type ◽  
Far Lateral Approach ◽  
Far Lateral ◽  
Fine Print

Object. The goal of this study was to determine whether drilling out the occipital condyle facilitates surgery via the far-lateral approach by comparing data from 10 clinical cases with that from studies of eight cadaver heads. Methods. During the last 6 years at Louisiana State University Health Sciences Center—Shreveport, 10 patients underwent surgery via the far-lateral approach to the foramen magnum. Six of these patients harbored anterior foramen magnum meningiomas, one patient a dermoid cyst, two patients vertebral artery (VA) aneurysms, and an additional patient suffered from rheumatoid disease of the craniocervical junction. The surgical approach consisted of retromastoid craniectomy and C-1 laminectomy. The seven tumors and the pannus of rheumatoid disease were completely excised, and the two aneurysms were clipped without drilling the occipital condyle. In one patient a chronic subdural hematoma was found 3 months after surgery, but no patient displayed any complication associated with surgery. It is significant that in no patient was a cerebrospinal fluid leak present. All patients experienced improved neurological function postoperatively. To compare surgical visibility, eight cadaveric specimens (16 sides) were studied, including delineation of the VA and its segments around the craniocervical junction. Increase in visibility as a function of fractional removal of the occipital condyle was quantified by measuring the degrees of visibility gained by removing one third and one half of the occipital condyle. Removal of one third of the occipital condyle produced a mean increase of 15.9° visibility, and removal of one half produced a mean increase of 19.9°. Conclusions. On the basis of their findings the authors conclude that removal of the occipital condyle is not necessary for the safe and complete resection of anterior intradural foramen magnum tumors.

The far lateral/combined supra- and infratentorial approach

1994 ◽  
Vol 81 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Hillel Z. Baldwin ◽  
Christopher G. Miller ◽  
Harry R. van Loveren ◽  
Jeffrey T. Keller ◽  
C. Phillip Daspit ◽  
...  
Keyword(s):  
Brain Stem ◽  
Craniovertebral Junction ◽  
Foramen Magnum ◽  
Lateral Approach ◽  
Direct Access ◽  
Content Type ◽  
Far Lateral Approach ◽  
Far Lateral ◽  
Lower Clivus ◽  
Neurovascular Structures

✓ A far lateral approach to the ventral brain stem, lower clivus, and anterior foramen magnum is described. Methods for further exposure of the superior petroclival region by incorporating a subtemporal craniotomy and posterior petrosectomy are also demonstrated. Eight sequentially illustrated steps depict this technique. The far lateral/combined supra- and infratentorial exposure is a comprehensive surgical approach that provides direct access to the entire anterior and lateral brain stem and craniovertebral junction. It minimizes brain-stem retraction and maximizes visualization of the neurovascular structures.

scholarly journals Muscular-stage Dissection during Far Lateral Approach and Its Transcondylar Extension

2018 ◽  
Vol 79 (S 04) ◽  
pp. S356-S361 ◽  
Author(s):  
Sakyo Hirai ◽  
Yoshiki Obata ◽  
Taketoshi Maehara ◽  
Masaru Aoyagi ◽  
Akihito Sato
Keyword(s):  
Vertebral Artery ◽  
Transverse Process ◽  
Foramen Magnum ◽  
Lateral Approach ◽  
Oblique Muscle ◽  
Occipital Condyle ◽  
Artery Dissection ◽  
Posterior Arch ◽  
Far Lateral Approach ◽  
Far Lateral

Background The far lateral approach includes exposure of the C1 transverse process, vertebral artery, posterior arch of the atlas, and occipital condyle. We designed a method for systematic muscular-stage dissection and present our experience with this approach. Operative Methods We used a horseshoe scalp flap that was reflected downward and medially. The lateral muscle layers were separated layer to layer to expose the suboccipital triangle. The medial muscle layers were separated in the midline and reflected in a single layer. At this stage, the midline of the C1 process and the foramen magnum were identified. The rectus capitis posterior major muscle was reflected to expose the posterior arch of the atlas. The C1 transverse process and vertebral artery were identified by reflection of the superior oblique muscle. The occipital condyle was separated accordingly. Results We used this method of muscular dissection in 10 patients (foramen magnum meningioma, n = 5; hypoglossal schwannoma, n = 2; others, n = 3). Systematic muscular-stage dissection facilitates identification of the anatomical landmarks with no vertebral artery injury. Gross total removal was obtained in all 9 patients with complex tumors. The patient with vertebral artery dissection successfully underwent proximal clipping. Conclusion Our muscular-stage dissection could contribute to safe and effective surgery for the far lateral approach.

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