Vertebral Artery Injury during Routine Posterior Cervical Exposure: Case Reports and Review of Literature

An anatomical investigation of the suboccipital- and inferior suboccipital triangles

The suboccipital triangle (ST) is a clinically relevant landmark in the posterior aspect of the neck and is used to locate and mobilize the horizontal segment of the third part of the vertebral artery before it enters the cranium. Unfortunately, this space is not always a viable option for vertebral artery exposition, and consequently a novel triangle, the inferior suboccipital triangle (IST) has been defined. This alternative triangle will allow surgeons to locate the artery more proximally, where its course is more predictable. The purpose of this study was to better define the anatomy of both triangles by measuring their borders and calculating their areas. Ethical clearance was obtained from the University of Pretoria (reference number: 222/2021) and both triangles were subsequently dissected out on both the left and right sides of 33 formalin-fixed human adult cadavers. The borders of each triangle were measured using a digital calliper and the areas were calculated using Herons Formula. The average area of the ST is 969.82±153.15 mm2, while the average area of the IST is 307.48±41.31 mm2. No statistically significant differences in the findings were observed between the sides of the body, ancestry, or sex of the cadavers. Measurement and analysis of these triangles provided important anatomical information and speak to their clinical relevance as surgical landmarks with which to locate the vertebral artery. Of particular importance here is the IST, which allows for mobilisation of this artery more proximally, should the ST be occluded.

Rating the incidence of iatrogenic vascular injuries in thoracic and lumbar spine surgery as regards the approach: A PRISMA-based literature review

PURPOSE

To assess the rate, timing of diagnosis, and repairing strategies of vascular injuries in thoracic and lumbar spine surgery as their relationship to the approach.

METHODS

PubMed, Medline, and Embase databases were utilized for a comprehensive literature search based on keywords and mesh terms to find articles reporting iatrogenic vascular injury during thoracic and lumbar spine surgery. English articles published in the last ten years were selected. The search was refined based on best match and relevance.

RESULTS

Fifty-six articles were eligible, for a cumulative volume of 261 lesions. Vascular injuries occurred in 82% of instrumented procedures and in 59% during anterior approaches. The common iliac vein (CIV) was the most involved vessel, injured in 49% of anterior lumbar approaches. Common iliac artery, CIV, and aorta were affected in 40%, 28%, and 28% of posterior approaches, respectively. Segmental arteries were injured in 68% of lateral approaches. Direct vessel laceration occurred in 81% of cases and recognized intraoperatively in 39% of cases.

CONCLUSIONS

Incidence of iatrogenic vascular injuries during thoracic and lumbar spine surgery is low but associated with an overall mortality rate up to 65%, of which less than 1% for anterior approaches and more than 50% for posterior ones. Anterior approaches for instrumented procedures are at risk of direct avulsion of CIV. Posterior instrumented fusions are at risk for injuries of iliac vessels and aorta. Lateral routes are frequently associated with lesions of segmental vessels. Suture repair and endovascular techniques are useful in the management of these severe complications.

Percutaneous Full-Endoscopic C2 Ganglionectomy for the Treatment of Intractable Occipital Neuralgia: Technical Note

BACKGROUND

The C-2 dorsal root ganglionectomy procedure can provide effective treatment for intractable occipital neuralgia (ON). However, the traditional microsurgery of C2 ganglionectomy needs a wide incision and significant paraspinous muscle dissection for adequate visualization. The indications of endoscopic spine surgery are ever expanding, with the development of endoscopic armamentaria and technological innovations.

OBJECTIVE

To validate the feasibility of the approach and describe several operative nuances based on the authors' experience. In this paper, the authors describe a patient with intractable ON who was successfully treated with a percutaneous full-endoscopic C2 ganglionectomy.

METHODS

We describe the case of an 83-yr-old female with a 2-yr history of left ON who did not respond to a series of treatments, including physical therapy, drug therapy, injection therapy, and radiofrequency therapy. After careful examination, we performed a percutaneous, full-endoscopic left C2 ganglionectomy.

RESULTS

The patient was successfully treated with a percutaneous full-endoscopic ganglionectomy. Afterwards, her intractable and constant pain was relieved. There was no cerebrospinal fluid leakage, incision infection, neck deformity, or other complications.

CONCLUSION

C2 ganglionectomy can be accomplished successfully using a full-endoscopic uniportal surgical technique under continuous irrigation, which has the advantages of excellent illumination and visualization, reduced surgery-related trauma, and reduced bleeding.

Rate and Characteristics of Vertebral Artery Injury Following C1-C2 Posterior Cervical Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Intraoperative vascular injuries in the cervical spine are rare, but carry significant morbidity and mortality when they do occur. There is a need to better characterize the risk of vertebral artery injury (VAI) after posterior C1-C2 fusion. The aim of this study was to investigate the rate of VAI in patients undergoing posterior C1-C2 cervical fusion.

METHODS

An electronic database search was performed to identify studies that reported rates of VAI following posterior cervical fusion at C1-C2 level. Patient-specific risk factors, surgical indication, surgical technique, and other data were collected for each study. Forest plots were created to outline the pooled ratios of VAI in the literature.

RESULTS

Eleven studies with 773 patients were identified. Mean age of patients was 48.47 years (range, 6-78 years), and most patients were female (61.7%, n = 399). Trauma was the most frequent indication for surgery (18.8%, n = 146), followed by inflammatory processes affecting the vertebrae (13.2%, n = 102). The rate of VAI per patient was 2% (95% confidence interval = 1%-4%) among 773 patients, while injury rate per screw was 1% (95% confidence interval = 0%-2%) among 2238 screws placed.

CONCLUSIONS

The rate of VAI after C1-C2 posterior cervical fusion was found to be 2% for each operated patient and 1% for each screw placed.

Use of O-arm With Intraoperative Arteriography for Localization and Stealth Navigation of the Vertebral Arteries During Posterior Cervical Spine Surgery

BACKGROUND

Vertebral artery injury (VAI) can be a devastating complication during cervical spine surgery. Although considered a rare occurrence overall, incidences of VAI have been reported in the ranges of 0.07% to 8%. Such injuries have the potential for catastrophic consequences, including blood loss, permanent morbid neurologic injury, and even death. The introduction of intraoperative navigation using either preoperative or intraoperative imaging has now been widely adopted in current practice so as to try and minimize adverse outcomes while giving real-time, dynamic information of the operative field. The use of the O-arm Surgical Imaging System during cervical spine surgery allows one to obtain high-resolution, accurate intraoperative imaging, and when used in concert with forms of intraoperative navigation, it can help with instrumentation and safety. However, patients undergoing cervical spine surgery do not routinely undergo preoperative vascular imaging, particularly with regard to anterior cervical or posterior high-cervical surgeries, where the incidence of VAI, in comparison with other cervical surgeries, has been reported to be the highest.

METHODS

Here we present the use of intraoperative O-arm-based arteriography for integration with navigation for vertebral artery localization during C1 to C3 posterior instrumentation and fusion of an unstable C2 fracture in a 54-year-old man.

RESULTS

The patient did not experience any intraoperative VAI and was subsequently discharged with no focal neurologic deficits.

CONCLUSIONS

Detailed in our report is our protocol and procedure for obtaining and using intraoperative angiographic images.

CLINICAL RELEVANCE

Case report detailing O arm for intraoperative identification of vertebral arteries during C1-C3 posterior instrumentation and fusion with pre-operative unilateral vertebral artery injury.

Three-Dimensional Evaluation and Classification of the Anatomy Variations of Vertebral Artery at the Craniovertebral Junction in 120 Patients of Basilar Invagination and Atlas Occipitalization

BACKGROUND

Patients with basilar invagination and atlas occipitalization usually present abnormal anatomy of the vertebral arteries (VAs) at the craniovertebral junction (CVJ).

OBJECTIVE

To describe and further classify different types of VA variations at the CVJ with 3D visualization technology.

METHODS

One hundred twenty patients with basilar invagination and atlas occipitalization who had undergone 3-dimensional computed tomographic angiography (3D-CTA) were retrospectively studied. Imaging data were processed via the separating, fusing, opacifying, and false-coloring-volume rendering technique. Abnormal anatomy of the VA at the CVJ was categorized and related anatomic parameters were measured.

RESULTS

Seven different types were classified. Type I, VAs enter the cranium after leaving VA groove on the posterior arch of atlas (26.7% of 240 sides); Type II, VAs enter an extraosseous canal created in the assimilated atlas lateral mass-occipital condyle complex before reaching the cranium (53.3%); Type III, VA courses above the axis facet or curves below the atlas lateral mass then enter the cranium (11.7%); Type IV, VAs enter the spinal canal under the axis lamina (1.3%); Type V, high-riding VA (31.3%); Type VI, fenestrated VA (2.9%); Type VII, absent VA (4.2%). Distance from the canal of Type II VA to the posterior facet surface of atlas lateral mass (5.51 ± 2.17 mm) means a 3.5-mm screw can be safely inserted usually. Shorter distance from the midline (13.50 ± 4.35) illustrates potential Type III VA injury during exposure. Decreased height and width of axis isthmus in Type V indicate increased VA injury risks.

CONCLUSION

Seven types of VA variations were described, together with valuable information helpful to minimize VA injury risk intraoperatively.

Analysis of Risk Factors for Posterior C1 Screw-Related Complication: A Retrospective Study of 358 Posterior C1 Screws

BACKGROUND

Although C1 screw fixation is becoming popular, only a few studies have discussed about the risk factors and the patterns of C1 screw complications.

OBJECTIVE

To investigate the incidence of C1 screw complications and analyze the risk factors of the C1 screw complications.

METHODS

A total of 358 C1 screws in 180 consecutive patients were analyzed for C1 screw complications. Screw malposition, occipital neuralgia, major complications, and total C1 screw complications were analyzed.

RESULTS

The distribution of C1 screw entry point is as follows: inferior lateral mass, 317 screws (88.5 %); posterior arch (PA), 38 screws (10.7 %); and superior lateral mass, 3 screws (0.8 %). We sacrificed the C2 root for 127 screws (35.5 %). C1 instrumentation induced 3.1 % screw malposition, 6.4 % occipital neuralgia, 0.6 % vascular injury, and 3.4 % major complications. In multivariate analysis, deformity (odds ratio [OR]: 2.10, P = .003), traumatic pathology (OR: 4.97, P = .001), and PA entry point (OR: 3.38, P = .001) are independent factors of C1 screw malposition. C2 root resection can decrease the incidence of C1 screw malposition (OR: 0.38, P = .012), but it is a risk factor of occipital neuralgia (OR: 2.62, P = .034). Advanced surgical experience (OR: 0.09, P = .020) correlated with less major complication.

CONCLUSION

The incidence of C1 screw complications might not be uncommon, and deformity or traumatic pathology and PA entry point could be the risk factors to total C1 screw complications. The PA screw induces more malposition, but less occipital neuralgia. C2 root resection can reduce screw malposition, but increases occipital neuralgia.

Iatrogenic Acute Ischemic Necrosis Due to Emergent Bleeding Control in Ventral Foramen Magnum Meningioma with Spinal Instability

Meningiomas are the most common benign intracranial tumors. They often require surgical resection and postoperative radiation/chemotherapy based on their histologic grade. While necrosis caused by preoperative embolization and spontaneous tumor infarction is appreciated by pathologists when staging meningiomas, intraoperative events including large bore artery occlusion may also alter the histopathologic picture of a benign meningioma. Hence, they should be considered when signs of unexpected ischemia and necrosis are found, as these same phenotypes are also hallmarks of a higher-grade disease. We describe a case of a man with a large ventral foramen magnum meningioma who underwent temporary intraoperative occlusion of the vertebral artery, leading to ischemic tumor necrosis with abundant neutrophil invasion when the tumor was eventually examined histologically.

Surgical Interventions for Cervical Radiculopathy Caused by a Vertebral Artery Loop: A Case Report and Review of the Literature

BACKGROUND

Aberrant vertebral artery loops are a rare clinical condition, with sparse data regarding the optimal treatment guidelines for individual patients. The heterogeneity of treatment options in the literature creates a problem when tailoring treatments to individual patients. In this review of the literature, multiple surgical treatments for cervical vertebral artery loops were analyzed and compared. In addition, this article provides a clinical case of a patient with a vertebral artery loop.

METHODS

A literature review was conducted to identify studies investigating surgical treatments for a vertebral artery loop. Different surgical techniques were examined and the involved techniques and approaches described. The outcomes were assessed for each study and the effectiveness of the treatment determined.

RESULTS

Twelve articles met the inclusion criteria for this review. Six types of surgical interventions were found in the literature. Each intervention had similar postoperative results, leading to either a significant improvement or a complete resolution of symptoms.

CONCLUSIONS

Multiple successful surgical interventions have been described in the medical literature. However, because of the lack of evidence-based studies, no surgical intervention protocol could be determined. Treatment should therefore be tailored to individual patients' characteristics. Because not every radiologically detected vertebral artery loop is the main reason for a patient's symptoms, a thorough multidisciplinary approach is justified and advocated in patients with an atypical presentation, before a neurosurgical intervention takes place. More deliberate clinical decisions can be made once the understanding of the pathogenesis of this rare disease entity has been established and treatment protocols formulated.

Intraoperative Doppler ultrasound as a means of preventing vertebral artery injury during Goel and Harms C1-C2 posterior arthrodesis: technical note

Vertebral artery injury (VAI) is a potential catastrophic complication of Goel and Harms C1-C2 posterior arthrodesis. Meticulous study of preoperative spinal CT angiography together with neuronavigation plays a fundamental role in avoiding VAI. Doppler ultrasonography may be an additional intraoperative tool, providing real-time identification of the vertebral artery (VA) and thus helping its preservation.Thirty-three consecutive patients with unstable odontoid fractures underwent Goel and Harms C1-C2 posterior arthrodesis. Surgery was performed with the aid of lateral fluoroscopic control in 16 cases (control group) that was supplemented by Doppler ultrasonography in 17 cases (Doppler group). Two patients in each group had a C1 ponticulus posticus. In the Doppler group, Doppler probing was performed during lateral subperiosteal muscle dissection, stepwise drilling, and tapping. Blood flow velocity in the V3 segment of the VA was recorded before and after posterior arthrodesis. All patients had a 12-month outpatient follow-up, and outcome was assessed using the Smiley-Webster Pain Scale. Neither VAI nor postoperative neurological impairments were observed in the Doppler group. In the control group, VAIs occurred in the 2 patients with C1 ponticulus posticus. In the Doppler group, 1 patient needed intra- and postoperative blood transfusions, and no difference in terms of Doppler signal or VA blood flow velocity was detected before and after C1-C2 posterior arthrodesis. In the control group, 3 patients needed intra- and postoperative blood transfusions.Useful in supporting fluoroscopy-assisted procedures, intraoperative Doppler may play a significant role even during surgeries in which neuronavigation is used, reducing the chance of a mismatch between the view on the neuronavigation screen and the actual course of the VA in the operative field and supplying the additional data of blood flow velocity.

Cervical Laminectomy With or Without Lateral Mass Instrumentation: A Comparison of Outcomes

STUDY DESIGN

Narrative review.

BACKGROUND

Cervical decompressive laminectomy is a common posterior approach for addressing multilevel cervical spondylotic myelopathy. However, there is a concern that cervical laminectomy can lead to kyphotic deformity with subsequent neurological decline. In this context, cervical laminectomy with fusion using lateral mass instrumentation has become increasingly utilized with the aim of reducing the risk of developing postoperative kyphotic deformity, which is thought to predispose to poorer neurological outcomes in the long term.

OBJECTIVE

To compare the evidence for stand-alone cervical laminectomy with laminectomy with posterior fusion in terms of clinical outcomes and the incidence of adverse events, particularly the development of postoperative cervical kyphosis.

MATERIAL AND METHODS

Initial Medline search using MeSH terms yielded 226 articles, 23 of which were selected. An additional PubMed search and the reference list of individual papers were utilized to identify the remaining papers of relevance.

RESULTS

Cervical laminectomy both with and without fusion offers effective decompression for symptomatic multilevel cervical spondylotic myelopathy. The incidence of postlaminectomy kyphosis is lower following posterior fusion; however, there seems to be no clinical-radiologic correlation given that patients who develop postoperative kyphosis often do not progress to clinical myelopathy. Furthermore, there are specific additional risks of posterior instrumentation that need to be considered.

CONCLUSION

In carefully selected patients with normal preoperative cervical sagittal alignment, stand-alone cervical laminectomy may offer acceptably low rates of postoperative kyphosis. In patients with preoperative loss of cervical lordosis and/or kyphosis, posterior fusion is recommended to reduce the risk of progression to postoperative kyphotic deformity, bearing in mind that radiologic evidence of kyphosis may not necessarily correlate with poorer clinical outcomes. Furthermore, the specific risks associated with posterior fusion (instrumentation failure, pseudarthrosis, infection, C5 nerve root palsy, and vertebral artery injury) need to be considered and weighed up against potential benefits.

Posterior identification and exposure of the V3 segment of the vertebral artery

Objective:

The purpose of this study was to define the anatomy of the V3 segment of the vertebral artery (VA) from the posterior approach.

Methods:

Ten formalin-fixed cadavers were carefully dissected bilaterally using landmark features to identify and safely expose the VA from the posterior. Measurements regarding morphometric characteristics of landmark features and feasible resection quantifications were obtained and analyzed. The C2 pars was resected completely in all cadavers, averaging 15.03 ± 1.06 mm in thickness.

Results:

The average diameter of the VA at the midline of C2 on the right side was 4.66 ± 0.51 mm compared to the left 5.2 ± 0.49 mm (P = 0.002). The distance of the VA from the midline increased from caudal to rostral. The distance between the VA to the lateral edge of the dura in the middle of the window of approach was 9.67 ± 0.81 mm. The rostral-caudal length of the window of approach was 21.94 ± 1.60 mm. The percentage of C2 body removal was 28.04% ± 6.09% through each side (249.55 ± 55.5/898.2 ± 146.17 mm²). While carefully exposing the VA, a posterior approach can be feasible in cases of injury during C1–C2 instrumentation or during resection of tumors of the C2 pars with or without extension into the C2 body.

Discussion:

The posterior approach for a C2 partial corpectomy can also be used as an adjunct to anterior approaches when necessary to widen the extent of bone resection.

Conclusion:

Exposure of the V3 segment of the vertebral artery was defined as well as the extent of C2 corpectomy through the posterior approach.

Anatomical study of occipital triangles: the 'inferior' suboccipital triangle, a useful vertebral artery landmark for safe postero-lateral skull base surgery

BACKGROUND

Vertebral artery (VA) identification within the suboccipital triangle is a key step in craniocervical junction surgery. Often VA exposition at this level is arduous (space-occupying lesions, previous surgery); to identify VA more proximally may prove useful in complex cases. An alternative triangle is present just below the suboccipital one, where VA can be easily controlled; we named it the inferior suboccipital triangle (IST). The aim of the study is to identify IST anatomical relations and VA space orientation and evaluate its practical utility in surgery.

METHODS

An anatomical study was performed on ten sides of five injected cadaverdic specimens. Relevant anatomical data were databased.

RESULTS

The IST is limited superiorly by the inferior oblique muscle, inferolaterally by the posterior intertransversarii muscle and inferomedially by the C2 lamina; VA at this level has a vertical course with a slight medial to lateral direction (mean 10.8°) and minor posterior to anterior inclination (mean 3.4°). VA within the IST has a constant course without significant loops or kinkings; periarterial venous plexus is less represented at this level. The IST measures an average of 1.89 cm², and VA at this level has an average length of 98 mm.

CONCLUSIONS

IST is a significantly large anatomical space where the VA course is rather regular, and its length is sufficient for vascular proximal control purposes. Periarterial venous plexus is less evident at this level, easing the surgical exposure. VA exposition within the IST can be used as an alternative option when space-occupying lesions, scars and stabilisation devices make arterial dissection hazardous in more cranial V3 segments.

Vertebral artery loops in surgical perspective

PURPOSE

Vertebral artery loop is a congenital or acquired anomaly. Vertebral artery loops are incidentally diagnosed during evaluation of neck problems and trauma. We aimed to present the incidence of VA loops using magnetic resonance angiography in consecutive patients and discuss epidemiological data including the gender, age, location, signs and symptoms, treatment approaches and outcomes of VA loops via analyzing literature.

METHODS

In the first leg of our two-legged study, consecutive patients were evaluated using magnetic resonance angiography to detect any medial loop of vertebral arteries. The study period was from October 2015 to March 2016. In the second leg, academic databases about medial loop of vertebral artery were screened. Case reports, case series, abstracts and references of relevant literature were searched manually to avoid any missing cases.

RESULTS

We evaluated 239 consecutive patients using magnetic resonance angiography. Twenty-one patients were excluded from the study due to inadequate image acquisition, aplastic vertebral artery and/or concomitant vertebral artery stenosis. Medial loop of V2 vertebral artery was observed in 13 patients (5.9 %): 9 with left, 2 with right and 2 with bilateral medial V2 loop. Patients with medial V2 loop were significantly older than patients with straight vertebral arteries (70.30 vs. 62.36, p = 0.028). In the literature analysis, VA loops were more commonly observed at V2 segment (90.5 %). Vertebral artery loops were mostly diagnosed at the 5th and 6th decades of life predominantly in females. The most common signs and symptoms were radiculopathy and/or neck pain, and signs and symptoms of vertebrobasilar insufficiency.

CONCLUSIONS

Concise pre-operative evaluation of the vertebral arteries is essential to avoid the injury of undiagnosed VA loops during surgery, which might result in catastrophic circumstances. Further evaluation of the vertebral arteries using MR angiography is required, especially in elder age, before cervical spine surgeries.