The management of vertebral artery injury in anterior cervical spine operation: a systematic review of published cases

Unilateral C1-C2 Posterior Fusion in a Patient With Right Vertebral Artery Anomaly With Intracanal Trajectory: A Case Report

CASE

A 59-year-old woman presented with progressively worsening neck pain and radicular symptoms. Cervical radiographs revealed C1-C2 dynamic instability. Magnetic resonance imaging and computed tomographic angiogram revealed an anomalous right vertebral artery with intracanal trajectory at C1. A unilateral left C1-C2 fusion with a C1 lateral mass screw and C2 transarticular screw placement was performed due to the anomalous artery. At 14-month follow-up, the patient's cervical symptoms had resolved.

CONCLUSION

In this patient with an aberrant vertebral artery who was indicated for C1-C2 fusion, a unilateral contralateral fusion with a C1 lateral mass screw and C2 transarticular screw was a satisfactory treatment option.

Preventing Iatrogenic Injury to the Vertebral Artery in Cervical Spine Surgery: A Case Report

SUMMARY OF BACKGROUND DATA

Iatrogenic injury of the vertebral artery (VA) in the context of surgical approaches to the cervical spine has been cited as a relatively rare complication with varying degrees of severity ranging from minimal injury to acute stroke and can result in death. It is estimated that ~50% of cases of iatrogenic VA injury are preventable after postoperatively examining a patient's preoperative imaging. Despite the low incidence (<2%) of this complication, the potential associated morbidity demonstrates the importance of meticulous preoperative vascular consideration.

OBJECTIVE

This study aims to emphasize the importance of preoperative vascular screening during anterior cervical access planning visualized through a rare case of a VA aberration in a 47-year-old patient.

STUDY DESIGN

This study is designed as a retrospective case report.

METHODS

A thorough chart review was performed for this subject including all prior medical records, imaging studies, imaging reports, operative notes, and communication records.

RESULTS

The subject was found to have a history of patent foramen ovale (PFO) repair with a rare vertebral artery malformation described as a medial transposition of the vertebral artery out of the vertebral artery foramen between C3 and C4.

CONCLUSIONS

Consideration of cervical anatomy, particularly the VA, is key to minimizing the risk of adverse surgical outcomes in both anterior and posterior approaches to the cervical spine. During the workup process, the patient's primary care providers, radiologists, and surgeons should be aware of the potential variations of the VA with particular attention given to the course of the VA on MR imaging.

LEVEL OF EVIDENCE

Level IV.

Intraoperative Stereotactic Arteriography in Complex Cervical Spine Surgery

Intra-operative navigation has revolutionized spinal instrumentation. The O-arm (a mobile X-ray system; Medtronic, Minneapolis, MN) is uniquely capable of enabling visualization of the spine in axial planes. The application of this technology is wide yet underutilized in terms of its capacity to image spinal vascular anatomy. We completed a retrospective chart review of the following case studies. A 24-year-old neurologically intact female presented with a Jefferson fracture without vertebral artery dissection after a motor vehicle accident. After the failure of conservative management due to pseudoarthrosis, the patient opted for fusion. Prior to the procedure, bilateral 5 French femoral sheaths were placed. After exposure, intraarterial (IA) contrast was injected prior to the O-arm spin to visualize both vertebral arteries, which were stretched and adjacent to a mobile boney segment. In the second case, a 71-year-old male presented with right shoulder pain and a flaccid left deltoid secondary to a large enhancing epidural lesion spanning C4-C7. Further work-up confirmed a diagnosis of metastatic intrahepatic cholangiocarcinoma. Prior to resection with cervical spinal stabilization, a right radial artery 4 French Glidesheath was placed. Prior to the O-arm spin, the right vertebral artery was selected, and intravenous contrast was injected to permit visualization of the vertebral artery, which was encased within the tumor and at significant risk for iatrogenic injury. Both patients tolerated the endovascular and spinal procedures well without vertebral artery injury. This is the first series to report the effective use of the O-arm for improved visualization of vascular anatomy during surgery for cervical spinal trauma and oncology.

Incidence of vertebral artery injury in patients undergoing cervical spine trauma surgery in correlation with surgical approach: A review

Spinal cord injuries at the cervical spine level represent the most consequential of the related injuries at all levels of the spine. They can trigger permanent unilateral or bilateral damage with conspicuous disability. Regarding unstable injuries, the gold standard approach is open reduction and osteosynthesis, which can select between anterior and posterior surgical access. Each of the aforementioned approaches demonstrates both advantages and disadvantages; thus, it is up to the surgeon to determine the optimal option concerning the patient's safety. Diligent intraoperative control of anatomical reduction is pivotal to obtaining the best feasible postoperative outcomes. Literature data delineate copious complications following surgical intervention in the cervical spine. Indubitably, the most crucial intraoperative complication accounts for vascular injuries, with the most preponderant being the corrosion of the vertebral artery, as it is potentially life-threatening. This paper aims to provide a succinct and compendious review of the existing literature regarding cervical spinal cord injuries and to deduce many inferences concerning the incidence of iatrogenic vertebral artery injuries in relation to the surgical approach for fracture reduction.

VertebralArtery Injury with Anterior Cervical Spine Operations: A Systematic Review of Risk Factors, Clinical Outcomes, and Management Strategies

OBJECTIVE

Anterior cervical spine operations are commonly performed on cervical spine pathologies and to a large extent are safe and successful. However, these surgical procedures expose the vertebral artery, posing a risk of harm to it.

METHODS

A systematic review was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to critically assess primary articles discussing treatment strategies "vertebral artery injury" AND "anterior cervical spine" and develop a management strategy based on our experience and meta-analysis of the literature. In addition, we present an illustrative case of iatrogenic vertebral artery injury presenting with 6 to 7 months' history of progressive dysphagia was transferred to our care from an outside institution.

RESULTS

Included and analyzed were 43 articles that detailed 75 cases involving vertebral artery injury (VAI) in anterior cervical spine operations. Preoperatively, frequent clinical findings reported were sensory deficit (26 patients [63.41%]), motor deficit (20 patients [48.78%]), and pain (17 patients [41.46%]). In total, 32 patients (50.00%) endured injury of their left VA, and 30 patients had a right VAI. The 2 common causes of VAI were drilling (24 patients [40.00%]) and instrumentation (8 patients [13.33%]).

CONCLUSIONS

Altogether, our review recommends repair or tamponade packing with a hemostatic agent for primary management. Should tamponade packing with a hemostatic agent be used for primary management, secondary management should entail either repair, stenting occlusion, embolization, anticoagulants, or ligation. Further examination of this treatment strategy based on a larger cohort is necessary.

The diagnostic accuracy of MRI and nonenhanced CT for high-risk vertebral artery anatomy for subaxial anterior cervical spine surgery safety

OBJECTIVE

Medial migration of the vertebral artery (VA) can be a risk factor for injury during anterior procedures. CT angiography (CTA) has been considered the gold standard for the evaluation of various areas of the arterial anatomy. MRI and nonenhanced CT are more commonly used as routine preoperative imaging studies, but it is unclear if these modalities can safely exclude the anomalous course of the VA. The aims of this cross-sectional observational study were to investigate risk factors for medially migrated VA on CTA and to evaluate the diagnostic accuracy of MRI and nonenhanced CT for high-risk VA anatomy in the subaxial cervical spine.

METHODS

The records of 248 patients who underwent CTA for any reason at a single academic institution between 2007 and 2018 were reviewed. The authors included MRI and nonenhanced CT taken within 1 year before or after CTA. An axial VA position classification was used to grade VA anomalies in the subaxial cervical spine. The multivariable linear regression analysis with mixed models was performed to identify the risk factors for medialized VA. The sensitivity and specificity of MRI and nonenhanced CT for high-risk VA positions were calculated.

RESULTS

A total of 175 CTA sequences met the inclusion criteria. The mean age was 63.8 years. Advanced age, disc and pedicle levels, lower cervical levels, and left side were independent risk factors for medially migrated VA. The sensitivities of MRI and nonenhanced CT for the detection of grade 1 or higher VA position were only fair, and the sensitivity of MRI was lower than that of nonenhanced CT (0.31 vs 0.37, p < 0.001), but the specificities were similarly high for both modalities (0.97 vs 0.97). With the combination of MRI and nonenhanced CT, the sensitivity significantly increased to 0.50 (p < 0.001 vs MRI and vs CT alone) with a minimal decrease in specificity.

CONCLUSIONS

Axial images of MRI and nonenhanced CT demonstrated high specificities but only fair sensitivities. Nonenhanced CT demonstrated better diagnostic value than MRI. When combining both modalities the sensitivity improved, but a substantial proportion of medialized VAs could not be diagnosed.

Anastomosis and Endovascular Treatment of Iatrogenic Vertebral Artery Injury

Iatrogenic vertebral artery injury (VAI) that occurs during cervical spine surgery can cause life-threatening complications, such as arteriovenous fistulas, catastrophic bleeding, neurological impairment, cerebral ischemia, and death. We report a case of dominant VAI during surgery and the treatment of a 60-year-old man diagnosed with a C1-2-3 metastatic spine tumor from urothelial carcinoma. Active bleeding occurred during tumor resection using pituitary forceps, immediately followed by gauze packing and manual compression. Post further resection, we found that the vertebral artery (VA) was completely severed. After temporary clamping on both sides of the damaged VA, an artificial graft anastomosis was performed. After verifying that the flow was intact using Doppler Sonography, Occiput-C1-4-5-6 posterolateral fusion was performed. Angiography was performed immediately after surgery. We found a thrombus occluding the left VA, and performed mechanical thrombectomy and stent insertion. The final angiography showed good VA flow with no emboli. In this case, VA anastomosis and endovascular treatment were performed within a relatively short period of time post VAI, and the patient was able to recover without any neurological deficits.

Prevalence of Vertebral artery anomaly in upper cervical and its surgical implications: a systematic review

BACKGROUND

The presence vertebral artery (VA) abnormalities in the upper cervical may be a potential cause of catastrophic complication in the posterior approach of the upper cervical spine surgery. The aim of this study was to demonstrate the real incidence of the V3 segment anomaly in patients who need upper cervical surgery, and tried to find out the risk factors of V3 segment anomaly to evaluate the necessary of computed tomographic angiography (CTA) for upper cervical surgery.

METHOD

This systematic review was conducted following the preferred reporting items for systematic reviews and meta-Analyses (PRISMA). Retrospective studies and reports of case series involving human subjects with data on anomalies of vertebral artery in upper cervical spine were included. Data on the prevalence of persistent first intersegmental artery (PIA), fenestration of the VA (FA), posterior inferior cerebellar artery (PICA) were extracted.

RESULTS

A total of 16 articles involving 5927 subjects met the inclusion criteria. The total incidence of V3 segment anomaly in the patients with bony abnormalities was 25.9% (74/286): PIA was 17.5%, FA was 6.6% and PICA was 1.8%. The total incidence of V3 segment anomaly in the patients without bony abnormalities was 2.7% (152/5671): PIA was 1.76%, FA was 0.4% and PICA was 0.5%. The total incidence of V3 segment anomaly in Asian population without bony abnormalities was 5.8%, while in European and American population was 0.8 and 0.6%, respectively.

CONCLUSION

Patients with bone abnormalities are high risk factor for VA abnormalities, CTA is of paramount importance to evaluate the variant VA anatomy. However, regarding to the low incidence of V3 variation in normal population, we do not recommend preoperative CT angiography as mandatory part of preoperative.

A quantitative analysis of the dimensions and content of the vertebral triangle

PURPOSE

The vertebral triangle (VT) located in the root of the neck most commonly contains the vertebral artery (VA), cervical sympathetic chain and certain roots of the brachial plexus. Although other structures have been reported, few studies have reported on the overall content of this space. Based on the current literature, there is a general paucity of anatomical information pertaining to the dimensional anatomy of the VT and specifically the structures related to it. Therefore, this study aimed to quantitatively analyze the size, position, content, and anatomical structures in relation to the vertebral triangle in a South African sample.

METHODS

Forty-three VTs were dissected on bodies donated to science. Measurements taken include the dimensions of the triangle, as well as distances between prominent structures and landmarks of the VT. Observations were made on the presence/absence of the varying neurovascular structures within the VT.

RESULTS

Mean height was 30.1 ± 1.51 mm (R) and 32.9 ± 1.78 mm (L). Mean width was 18.3 ± 0.74 mm (R) and 19.3 ± 0.98 mm (L). The C8 spinal nerve was found on average approximately halfway [16.4 ± 0.74 mm (R) and 15.9 ± 0.95 mm (L)] in the VT. The VA was present in the VT in 100% of the sample and the C7 spinal nerve and inferior sympathetic ganglia were present in more than 80% of the sample.

CONCLUSION

Understanding the VT and the content is of the utmost importance and of great interest to neurosurgeons, to avoid these important neurovascular structures and prevent iatrogenic complications during surgery.

Vertebral Artery Injury in the Cervical Spine: Anatomy, Diagnosis, and Management

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Although rare, injury to the vertebral artery (VA) can occur after blunt trauma or iatrogenically during surgery. Clinicians should be aware of the anatomic variants of the VA, the presence of which may increase the risk of iatrogenic VA injury (VAI).

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If VAI is suspected following blunt trauma, rapid identification via advanced imaging modalities, such as computed tomography angiography, can help clarify the site of injury and guide management.

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VAI can be classified according to the Denver grading scale for blunt cerebrovascular injury, ranging from grade I to grade V, which includes intimal narrowing, pseudoaneurysm formation, complete occlusion, and arterial transection.

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Treatment modalities remain controversial and include anticoagulation, endovascular interventions, surgical tamponade, ligation, and microvascular repair. The choice of treatment is influenced by the setting of the injury (iatrogenic injury in the operating room versus blunt trauma in the field) and the laterality of the dominant VA with respect to brain perfusion.

Management of Asymptomatic Vertebral Artery Injury Caused by a Cervical Pedicle Screw Malposition: Two Case Reports

Iatrogenic vertebral artery (VA) injury in cervical fusion is an extremely rare complication but can lead to serious sequelae. We present two successful cases of internal trapping for preventing delayed-onset ischemic stroke after iatrogenic VA stenosis caused by a cervical pedicle screw. A 34-year-old female underwent posterior cervical fusion for C4/C5 dislocation fracture. No neurological deficits were observed after the operation. However, the postoperative images revealed that the left C5 pedicle screw perforated the transverse foramen, and the left VA was suspected to be occluded at the screw insertion site. Before revision surgery, we tried to embolize the injured VA with coils. A microcatheter could be navigated from the ipsilateral VA to the distal of the screw, and internal trapping was performed with coils. Another case is that of a 50-year-old male with cervical spondylosis, who underwent posterior decompression and cervical fusion. The neurological symptoms did not deteriorate after the operation. However, the postoperative computed tomography images revealed the perforation of the right C3 transverse foramen by the pedicle screw. In right vertebral angiography, about 70% stenosis was observed at the screw insertion site. Although revision surgery was not planned due to good stability, we embolized the right VA after balloon occlusion test, to prevent the delayed-onset thromboembolic complications. Both the patients recovered without any neurological deficits. Iatrogenic VA injuries, even if asymptomatic immediately after surgery, can lead to serious sequelae in case of delayed-onset ischemic stroke. Therefore, careful attention should be paid when the screw perforates the transverse foramen.

Computed tomographic angiography to analyze dangerous vertebral artery anomalies at the craniovertebral junction in patients with basilar invagination

OBJECTIVE

Failure to detect dangerous anatomic vertebral artery anomalies (AVAAs) and dangerous functional vertebral artery anomalies (FVAAs) at the craniovertebral junction (CVJ) in patients with basilar invagination (BI) can result in major complications such as intraoperative vertebral artery injury, brain infarctions, and even death. Iatrogenic vertebral artery injury is a rare but severe complication of cervical spine surgery. We aimed to evaluate dangerous vertebral artery anomalies at the CVJ in patients with BI using computed tomographic angiography (CTA).

METHODS

CTA images of 61 BI patients were retrospectively analyzed to evaluate AVAAs and FVAAs at the CVJ. Dangerous AVAAs include a persistent first intersegmental artery (FIA), fenestration of the vertebral artery (FEN), and posterior inferior cerebellar artery with an extradural C1/2 origin (PICA-C1/2). Dangerous FVAAs include a dominant vertebral artery (DVA) and hypoplastic vertebral artery ending in the PICA (HVA-PICA) without joining the basilar artery.

RESULTS

Overall, 31 female and 30 male patients (mean age, 42.3 years) were included. The incidences of FIA, FEN, and PICA-C1/2 were 29.5 % (18/61), 3.3 % (2/61), and 3.3 % (2/61), respectively, whereas the incidences of DVA and HVA-PICA were 36.1 % (22/61) and 1.65 % (1/61), respectively.

CONCLUSION

Dangerous vertebral artery anomalies at the CVJ have a high incidence in patients with BI. Preoperative CTA is highly recommended in such patients to identify anomalous vertebral arteries and reduce the risk of intraoperative injury.

A Novel and Reproducible Classification of the Vertebral Artery in the Subaxial Cervical Spine

BACKGROUND

An injury of the vertebral artery (VA) is one of the most catastrophic complications in the setting of cervical spine surgery. Anatomic variations of the VA can increase the risk of iatrogenic lacerations.

OBJECTIVE

To propose a novel and reproducible classification system that describes the position of the VA based on a 2-dimensional map on computed tomography angiographs (CTA).

METHODS

This cross-sectional retrospective study reviewed 248 consecutive CTAs of the cervical spine at a single academic institution between 2007 and 2018. The classification consists of a number that characterizes the location of the VA from the medio-lateral (ML) aspect of the vertebral body. In addition, a letter describes the VA location from the anterior-posterior (AP) aspect. The reliability and reproducibility were assessed by 2 independent raters on 200 VAs.

RESULTS

The inter- and intrarater reliability values showed the classification's reproducibility. The inter-rater reliability weighted κ-value for the ML aspect was 0.93 (95% CI: 0.93-0.93). The unweighted κ-value was 0.93 (95% CI: 0.86-1.00) for "at-risk" positions (ML grade ≥1), and 0.87 (95% CI: 0.75-1.00) for "high-risk" positions (ML grade ≥2). The weighted κ-value for the intrarater reliability was 0.94 (95% CI: 0.95-0.95). The unweighted κ-values for the intrarater reliability were 0.95 (95% CI: 0.91-0.99) for "at-risk" positions, and 0.87 (95% CI: 0.78-0.96) for "high-risk" positions.

CONCLUSION

The proposed classification is reliable, reproducible, and independent of individual anatomic size variations. The use of this novel grading system could improve the understanding and interdisciplinary communication about VA anomalies.

Posterior Inferior Cerebellar Artery Infarction Originating at C1-2 after C1-2 Fusion

Vertebral artery injuries associated with C1 lateral mass screw insertion rarely occur during C1-2 fusion. The posterior inferior cerebellar artery (PICA) is uncommonly located at the C1 lateral mass insertion position. A 71-year-old woman with atlanto-axial subluxation and cord compression underwent C1-2 fusion. Sixth nerve palsy and diplopia were detected postoperatively, and decreased consciousness occurred on postoperative day 4. Brain magnetic resonance image (MRI) and computed tomography (CT) revealed PICA infarction. In the preoperative CT angiography, the PICA originated between the C1 and C2 level. In the postoperative CT scan, the PICA was not visible. The patient was treated conservatively for two weeks and recovered. PICA originating between the C1 and C2 level comprises 1.1–1.3% of cases. Therefore, vertebral artery anomalies should be evaluated prior to C1-2 fusion to prevent vessel injuries.

Safe and bloodless exposure of the third segment of the vertebral artery: a step-by-step overview based on over 50 personal cases

Craniovertebral junction surgery usually requires the exposure of the third segment of the vertebral artery (V3). However, the complexity of musculature, a relatively high incidence of anomalies in the course of the vertebral artery (VA), and the presence of a rich venous plexus in this region make the V3 exposure challenging with a high risk of serious complications while taking down the suboccipital muscles in a single layer. A muscle dissection in interfascial layers, however, overcomes the drawbacks inherent in a blind dissection of the V3 as each of the muscles represents substantial landmark aiding subsequent step of the procedure and thus helping identify underlying anatomical structure early and safely. Moreover, along with a bloodless VA dissection off its surrounding venous plexus, it permits a safe and comfortable V3 exposure during the surgically demanding procedures.

Airway management in a displaced comminuted fracture of the mandible and atlas with a vertebral artery injury: A case report

Complex cervical spine fractures are a serious complications of maxillofacial trauma and associated with high mortality and neurological morbidity. Strict vigilance in preventing further insult to the cervical spine is a crucial step in managing patients who are at risk for neurologic compromise. We report a rare case of a right transverse process of atlas fracture with right-sided vertebral artery injury that was associated with a comminuted fracture of the body and angle of the mandible, which restricted mouth opening. Airway management was performed by an awake fiber-optic nasotracheal intubation, where neck movement was avoided with a cervical collar. Vertebral artery injuries may have disastrous consequences, such as basilar territory infarction and death, and should be suspected in patients with head and neck trauma. After mandibular plating, the patient was on cervical collar immobilization for 12 weeks and anti-coagulant therapy.

Anterior cervical spine surgery-associated complications in a retrospective case-control study

Anterior cervical spine procedures have been associated with satisfactory outcomes. However, the occurrence of troublesome complications, although uncommon, needs to be taken into consideration. The purpose of our study was to assess the actual incidence of anterior cervical spine procedure-associated complications and identify any predisposing factors. A total of 114 patients undergoing anterior cervical procedures over a 6-year period were included in our retrospective, case-control study. The diagnosis was cervical radiculopathy, and/or myelopathy due to degenerative disc disease, cervical spondylosis, or traumatic cervical spine injury. All our participants underwent surgical treatment, and complications were recorded. The most commonly performed procedure (79%) was anterior cervical discectomy and fusion (ACDF). Fourteen patients (12.3%) underwent anterior cervical corpectomy and interbody fusion, seven (6.1%) ACDF with plating, two (1.7%) odontoid screw fixation, and one anterior removal of osteophytes for severe Forestier's disease. Mean follow-up time was 42.5 months (range, 6-78 months). The overall complication rate was 13.2%. Specifically, we encountered adjacent intervertebral disc degeneration in 2.7% of our cases, dysphagia in 1.7%, postoperative soft tissue swelling and hematoma in 1.7%, and dural penetration in 1.7%. Additionally, esophageal perforation was observed in 0.9%, aggravation of preexisting myelopathy in 0.9%, symptomatic recurrent laryngeal nerve palsy in 0.9%, mechanical failure in 0.9%, and superficial wound infection in 0.9%. In the vast majority anterior cervical spine surgery-associated complications are minor, requiring no further intervention. Awareness, early recognition, and appropriate management, are of paramount importance for improving the patients' overall functional outcome.

Anterior cervical distraction and screw elevating-pulling reduction for traumatic cervical spine fractures and dislocations: A retrospective analysis of 86 cases

Treatment of cervical fracture and dislocation by improving the anterior cervical technique.Anterior cervical approach has been extensively used in treating cervical spine fractures and dislocations. However, when this approach is used in the treatment of locked facet joints, an unsatisfactory intraoperative reduction and prying reduction increases the risk of secondary spinal cord injury. Thus, herein, the cervical anterior approach was improved. With distractor and screw elevation therapy during surgery, the restoration rate is increased, and secondary injury to the spinal cord is avoided.To discuss the feasibility of the surgical method of treating traumatic cervical spine fractures and dislocations and the clinical application.This retrospective study included the duration of patients' hospitalization from January 2005 to June 2015. The potential risks of surgery (including death and other surgical complications) were explained clearly, and written consents were obtained from all patients before surgery.The study was conducted on 86 patients (54 males and 32 females, average age of 40.1 ± 5.6 years) with traumatic cervical spine fractures and dislocations, who underwent one-stage anterior approach treatment. The effective methods were evaluated by postoperative follow-up.The healing of the surgical incision was monitored in 86 patients. The follow-up duration was 18 to 36 (average 26.4 ± 7.1) months. The patients achieved bones grafted fusion and restored spine stability in 3 to 9 (average 6) months after the surgery. Statistically, significant improvement was observed by Frankel score, visual analog scale score, Japanese Orthopedic Association score, and correction rate of the cervical spine dislocation pre- and postoperative (P < .01).The modified anterior cervical approach is simple with a low risk but a good effect in reduction. In addition, it can reduce the risk of iatrogenic secondary spinal cord injury and maintain optimal cervical spine stability as observed during follow-ups. Therefore, it is suitable for clinical promotion and application.

Intraoperative Death During Cervical Spinal Surgery: A Retrospective Multicenter Study

STUDY DESIGN

A retrospective multicenter study.

OBJECTIVE

Routine cervical spine surgeries are typically associated with low complication rates, but serious complications can occur. Intraoperative death is a very rare complication and there is no literature on its incidence. The purpose of this study was to determine the intraoperative mortality rates and associated risk factors in patients undergoing cervical spine surgery.

METHODS

Twenty-one surgical centers from the AOSpine North America Clinical Research Network participated in the study. Medical records of patients who received cervical spine surgery from January 1, 2005, to December 31, 2011, were reviewed to identify occurrence of intraoperative death.

RESULTS

A total of 258 patients across 21 centers met the inclusion criteria. Most of the surgeries were done using the anterior approach (53.9%), followed by posterior (39.1%) and circumferential (7%). Average patient age was 57.1 ± 13.2 years, and there were more male patients (54.7% male and 45.3% female). There was no case of intraoperative death.

CONCLUSIONS

Death during cervical spine surgery is a very rare complication. In our multicenter study, there was a 0% mortality rate. Using an adequate surgical approach for patient diagnosis and comorbidities may be the reason how the occurrence of this catastrophic adverse event was prevented in our patient population.

Epidemiology and Outcomes of Vertebral Artery Injury in 16 582 Cervical Spine Surgery Patients: An AOSpine North America Multicenter Study

STUDY DESIGN

A multicenter retrospective case series was compiled involving 21 medical institutions. Inclusion criteria included patients who underwent cervical spine surgery between 2005 and 2011 and who sustained a vertebral artery injury (VAI).

OBJECTIVE

To report the frequency, risk factors, outcomes, and management goals of VAI in patients who have undergone cervical spine surgery.

METHODS

Patients were evaluated on the basis of condition-specific functional status using the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) score, the Nurick scale, and the 36-Item Short-Form Health Survey (SF-36).

RESULTS

VAIs were identified in a total of 14 of 16 582 patients screened (8.4 per 10 000). The mean age of patients with VAI was 59 years (±10) with a female predominance (78.6%). Patient diagnoses included myelopathy, radiculopathy, cervical instability, and metastatic disease. VAI was associated with substantial blood loss (770 mL), although only 3 cases required transfusion. Of the 14 cases, 7 occurred with an anterior-only approach, 3 cases with posterior-only approach, and 4 during circumferential approach. Fifty percent of cases of VAI with available preoperative imaging revealed anomalous vessel anatomy during postoperative review. Average length of hospital stay was 10 days (±8). Notably, 13 of the 14 (92.86%) cases resolved without residual deficits. Compared to preoperative baseline NDI, Nurick, mJOA, and SF-36 scores for these patients, there were no observed changes after surgery (P = .20-.94).

CONCLUSIONS

Vertebral artery injuries are potentially catastrophic complications that can be sustained from anterior or posterior cervical spine approaches. The data from this study suggest that with proper steps to ensure hemostasis, patients recover function at a high rate and do not exhibit residual deficits.

Long-term clinical outcomes following 3- and 4-level anterior cervical discectomy and fusion

OBJECTIVE The purpose of this study was to report the long-term clinical outcomes following 3- and 4-level anterior cervical discectomy and fusion (ACDF). METHODS A retrospective review of all adult neurosurgical patients undergoing elective ACDF for degenerative disease at a single institution between 1996 and 2013 was performed. Patients who underwent first-time 3- or 4-level ACDF were included; patients with previous cervical spine surgery, those undergoing anterior/posterior approaches, and those with corpectomy were excluded. Outcome measures included perioperative complication rates, fusion rates, need for revision surgery, Nurick Scores, Odom's criteria, symptom resolution, neck visual analog scale (VAS) pain score, and persistent narcotics usage. RESULTS Seventy-one patients who underwent 3-level ACDF and 26 patients who underwent 4-level ACDF were identified and followed for an average of 7.6 ± 4.2 years. There was 1 case (3.9%) of deep wound infection in the 4-level group and 1 case in the 3-level group (1.4%; p = 0.454). Postoperatively, 31% of patients in the 4-level group complained of dysphagia, compared with 12.7% in the 3-level group (p = 0.038). The fusion rate was 84.6% after 4-level ACDF and 94.4% after 3-level ACDF (p = 0.122). At last follow-up, a significantly higher proportion of patients in the 4-level group continued to have axial neck pain (53.8%) than in the 3-level group (31%; p = 0.039); the daily oral morphine equivalent dose was significantly higher in the 4-level group (143 ± 97 mg/day) than in the 3-level group (25 ± 10 mg/day; p = 0.030). Outcomes based on Odom's criteria were also different between cohorts (p = 0.044), with a significantly lower proportion of patients in the 4-level ACDF group experiencing an excellent/good outcome. CONCLUSIONS In this study, patients who underwent 4-level ACDF had significantly higher rates of dysphagia, postoperative neck pain, and postoperative narcotic usage when compared with patients who underwent 3-level ACDF. Pseudarthrosis and deep wound infection rates were also higher in the 4-level group, although this did not reach statistical significance. Additionally, a smaller proportion of patients achieved a good/excellent outcome in the 4-level group than in the 3-level group. These findings suggest a significant increase of perioperative morbidity and worsened outcomes for patients who undergo 4- versus 3-level ACDF.

Risks for Vascular Injury During Anterior Cervical Spine Surgery: Prevalence of a Medial Loop of Vertebral Artery and Internal Carotid Artery

STUDY DESIGN

Observational study using a retrospective single-institute database.

OBJECTIVE

To investigate the prevalence of a medial loop (ML) of the vertebral artery (VA) and internal carotid artery (ICA), which might be an anatomical risk factor for arterial injury in anterior cervical surgeries.

SUMMARY OF BACKGROUND DATA

Anterior cervical spine surgeries are generally considered to be safe and effective. VA injury is one of the most serious complications during anterior procedures. Several articles have reported this complication, which might be because of the anomalous course of VA at V2 segment. The prevalence and anatomical features of those high-risk cases were, however, not investigated.

METHODS

Consecutive Japanese subjects, who underwent contrast-enhanced computed tomography (CT) or computed tomographic angiography (CTA) for reasons other than evaluation of cervical artery disease from November 2011 to October 2012 in our institution, were reviewed. Exclusion criteria included poor images, past surgery, and endovascular intervention of cervical spine and its vessels. The definition of ML was set as the course of VA and ICA extended medially inside the uncovertebral joint. We also investigated whether those anomalous courses were detectable by plain CT.

RESULTS

A total of 1251 subjects with age ranging from 14 to 93 years with a mean of 56.1 years were surveyed. Among them, 1054 subjects were eligible and the others were excluded. A total of 421 subjects were male, and 633 were female. There were 10 cases (1%) with an ML of the VA, and 2 (0.2%) cases with a medial loop of internal carotid artery. Five of the 10 cases with a medial loop of vertebral artery were aberrant into the vertebral body, which were detectable by plain CT. Importantly, the other five cases could not be seen on the CT.

CONCLUSION

One percent of all subjects showed higher anatomical risk for VA and ICA injury during anterior surgery, half of which were undetectable by plain CT. Preoperative evaluation for vascular anatomy may be necessary for safer surgical treatment.

LEVEL OF EVIDENCE

4.

Comparison between anterior cervical discectomy with fusion and anterior cervical corpectomy with fusion for the treatment of cervical spondylotic myelopathy: a meta-analysis

BACKGROUND

Whether anterior cervical discectomy with fusion (ACDF) or anterior cervical corpectomy with fusion (ACCF) is superior in the treatment of cervical spondylotic myelopathy remains controversial. Therefore, we conducted a meta-analysis to quantitatively compare the efficacy and safety of ACDF and ACCF in the treatment of cervical spondylotic myelopathy.

METHODS

PubMed, Embase, Web of Science, SinoMed (Chinese BioMedical Literature Service System, People's Republic of China), and CNKI (China National Knowledge Infrastructure, People's Republic of China) were systematically searched to identify all available studies comparing efficacy and safety between patients receiving ACDF and ACCF. The weighted mean difference (WMD) was pooled to compare the Japanese Orthopaedic Association scores, visual analog scale scores, hospital stay, operation time, and blood loss. The risk ratio was pooled to compare the incidence of complications and fusion rate. Pooled estimates were calculated by using a fixed-effects model or a random-effects model according to the heterogeneity among studies.

RESULTS

Eighteen studies (17 observational studies and one randomized controlled trial) were included in this meta-analysis. Our results suggest that hospital stay (WMD =-1.33, 95% confidence interval [CI]: -2.29, -0.27; P=0.014), operation time (WMD =-26.9, 95% CI: -46.13, -7.67; P=0.006), blood loss (WMD =-119.36, 95% CI: -166.94, -71.77; P=0.000), and incidence of complications (risk ratio =0.51, 95% CI: 0.33, 0.80; P=0.003) in the ACDF group were significantly less than that in the ACCF group. However, other clinical outcomes, including post-Japanese Orthopaedic Association score (WMD =-0.27, 95% CI: -0.57, 0.03; P=0.075), visual analog scale score (WMD =0.03, 95% CI: -1.44, 1.50; P=0.970), and fusion rate (risk ratio =1.04, 95% CI: 0.99, 1.09; P=0.158), between the two groups were not significantly different.

CONCLUSION

Evidence from the meta-analysis of 18 studies demonstrated that surgical options of cervical spondylotic myelopathy using ACDF or ACCF seemed to have similar clinical outcomes. However, ACDF was found to be superior to ACCF in terms of hospital stay, operation time, blood loss, and incidence of complications.

Anterior cervical discectomy and fusion may be more effective than anterior cervical corpectomy and fusion for the treatment of cervical spondylotic myelopathy

BACKGROUND

This meta-analysis explored the efficacy and safety of anterior cervical corpectomy and fusion (ACCF) comparing to anterior cervical discectomy and fusion (ACDF) in treating cervical spondylotic myelopathy (CSM) patients.

METHODS

Several electronic databases were searched combined with manually searching. Thirteen randomized controlled studies were enrolled with 1,062 CSM patients, including 468 patients and 594 patients in the in the ACCF and ACDF group, respectively. The meta-analysis was then performed using the STATA 12.0 software. Crude standard mean difference (SMD) or odds ratio (OR) with their 95% confidence intervals (CI) were calculated.

RESULTS

Our meta-analysis results revealed that CSM patients in ACDF group showed less blood loss than those in ACCF group (SMD = 1.21, 95% CI = 1.03 ~ 1.39, P < 0.001). The operation time of CSM patients in the ACDF group was also obviously shorter than those in ACCF group (SMD = 0.40, 95% CI = 0.23 ~ 0.57, P < 0.001). Furthermore, CSM patients in ACDF group had shorter hospital time than those in ACCF group (SMD = 0.45, 95% CI = 0.21 ~ 0.69, P < 0.001).

CONCLUSION

Our findings provide empirical evidence that ACDF may be more effective than ACCF for CSM treatment.

Optimal measurement for "posterolateral protrusion" of the vertebral artery at the craniovertebral junction using computed tomography angiography

PURPOSE

Among extraosseous abnormalities of the vertebral artery (VA) at the craniovertebral junction (CVJ), available evidence regarding "posterolateral protrusion," the VA running distant from the groove over the superior surface of the posterior arch of the atlas, is limited. The purpose of this study was to determine the optimal measurement to indicate posterolateral protrusion of the VA.

MATERIALS AND METHODS

Computed tomography angiography (CTA) images of 40 consecutive patients with cervical disease were reviewed. Ultimately, 66 arteries were included in this study. Five parameters predicted to indicate posterolateral protrusion of the VA were defined (A-E) and measured by two surgeons twice over a 2-week interval. Intraclass correlation coefficients (ICC) were used to examine intra-observer reproducibility and inter-observer reliability. Receiver operating characteristic (ROC) curve analysis was performed to determine the most optimal parameter to predict posterolateral protrusion of the VA.

RESULTS

Excellent inter-observer reliability and intra-observer reproducibility were obtained for all parameters (ICC = 0.87-0.99). Among them, parameter A, defined as the maximal length from the outer surface of the VA to the outer surface of the posterior arch of the atlas, was most accurately described posterolateral protrusion of the VA. The optimal cut-off value of parameter A obtained with ROC curves was 8.3 mm (sensitivity 97.5%, specificity 100%).

CONCLUSIONS

The measurement in this study can quantitatively evaluate the posterolateral protrusion of the VA. Before posterior surgery at the CVJ, pre-operative CTA can help surgeons detect anomalous VA and reduce the risk of intra-operative VA injury.

Multimodality management of vertebral artery injury sustained during cervical or craniocervical surgery

BACKGROUND

Iatrogenic vertebral artery (VA) injury is a rare but potentially devastating complication associated with cervical and craniocervical surgery.

OBJECTIVE

To retrospectively evaluate treatment modalities and outcomes associated with iatrogenic VA injury.

METHODS

Our institutional surgical database was queried for patients who underwent cervical or craniocervical surgery from January 1997 to August 2012.

RESULTS

During this time period, 8213 patients underwent cervical or craniocervical surgery, and 17 (0.2%) cases of VA injury were identified. Eight (47%) of these injuries occurred during C1-2 instrumentation procedures. Primary microsurgical repair of the VA was performed in 5 patients. Other cases were managed by either surgical or endovascular VA occlusion. Of the 17 patients, 15 underwent immediate angiography, 9 of whom were ultimately treated by the use of endovascular techniques.

CONCLUSION

VA injury is an uncommon complication of cervical and/or skull base surgery. Standardized management recommendations may help reduce complications associated with these rare but potentially devastating injuries.

Variations in Entrance of Vertebral Artery in Korean Cervical Spine: MDCT-based Analysis

Background

Knowledge of the anatomical variation of the vertebral artery has clinical importance not only for the performance of interventional or surgical procedures itself but also to ensure their safety. We conducted a study of the anatomical variation by reviewing multi-detector computed tomography (MDCT) images of the cervical spine from 460 Korean patients.

Methods

16-row MDCT data from 460 patients were used in this study. We observed 920 vertebral arteries. Examination points included level of entrance of the artery into the transverse foramen of the cervical vertebra, origin site of the vertebral artery, course of a vertebral artery with aberrant entrance.

Result

The vertebral artery in 2 (0.2%) cases in this study entered into the transverse foramen of the 7th cervical vertebra from the left. In 45 (4.9%) cases, the vertebral artery entered into the transverse foramen of the 5th cervical vertebra. Of these, the entrance was on the right in 15 (1.6%) and on the left in 30 (3.3%). We found 17 (1.8%) cases in which the artery entered into the transverse foramen of the 4th cervical vertebra, 10 (1.1%) on the right and 7 (0.7%) on the left side. As is commonly acknowledged, the 6th cervical vertebra was the most common site of entry; the vertebral artery entered the transverse foramen of the 6th cervical vertebra in the remaining 855 (93.0%) cases, on the right in 434 (47.2%) and on the left in 421 (45.8%).

Conclusions

In conclusion, the possibility of an atypical course of the vertebral artery in segments V1 and V2 should be evaluated with magnetic resonance imaging (MRI) or CT images before carrying out procedures involving the anterior cervical vertebrae.

Sentinel events in cervical spine surgery

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

A national population-based database was queried to investigate the incidence of sentinel events in cervical spine surgery as well as the associated perioperative outcomes.

SUMMARY OF BACKGROUND DATA

Sentinel events in cervical spine surgery are potentially catastrophic complications. The incidence and perioperative outcomes associated with sentinel events in cervical spine surgery have not been well characterized.

METHODS

The Nationwide Inpatient Sample was queried from 2002 to 2011. Patients who underwent elective cervical spinal surgery were identified. Sentinel events including esophageal perforation, vascular injury, nerve injury, retention of foreign objects, and wrong-site surgery were identified. Patient demographics, comorbidities (Charlson Comorbidity Index), surgical procedures, length of stay, total hospital costs, and postoperative outcomes were assessed. The risk for in-hospital mortality associated with each complication was calculated using a 95% confidence interval (CI). Statistical analysis was performed with SPSS version 20, and a P ≤ 0.001 denoted significance.

RESULTS

A total of 251,318 cervical spine procedures were identified between 2002 and 2011, of which 123 patients (0.5 per 1000 cases) incurred sentinel events. Circumferential cervical fusion (anterior-posterior cervical fusion) demonstrated an increased risk of vascular injury (odds ratio [OR], 4.5; CI, 1.8-11.2), whereas cervical total disc replacement was associated with an increased risk of esophageal perforation (OR, 10.9; CI, 1.4-85.2) and nerve injury (OR, 36.4; CI, 1.5-892.3). Posterior cervical fusions were associated with an increased risk of wrong-site surgery (OR, 3.9; CI, 1.5-10.5). The sentinel event cohort incurred longer hospitalization, greater costs, mortality, and greater incidence of postoperative complications.

CONCLUSION

This database analysis demonstrates that sentinel events are associated with a significant increase in hospital resource utilization and worsened perioperative outcomes. The type of cervical spine procedure and the number of fusion levels significantly impact the risk of sentinel events. Further research is warranted to understand the etiology of sentinel events in cervical spine surgery and to implement protocols to mitigate the associated risk factors.

LEVEL OF EVIDENCE

4.