Prolonged retraction on the normal common carotid artery induced lethal stroke after cervical spine surgery

Postoperative Stroke Following Anterior Cervical Spine Surgery: A Case Report

Vascular complications succeeding anterior cervical spine surgery are rare, but their consequences represent a major burden for the patient. Cerebral infarction following anterior cervical discectomy and fusion (ACDF) is uncommon. However, screening for risk factors before surgery should become mandatory. We present the case of a patient with no significant medical history who underwent ACDF for a C5/C6 herniated disc with myelopathy. Although the surgery was uneventful, after the surgery, partial right palpebral ptosis and miosis were noted, suggestive of Horner syndrome. On the fifth postoperative day, the patient experienced left hemiplegia and drowsiness. An emergency CT scan and cerebral MRI revealed ischemia in the right middle cerebral artery territory. The patient was transferred to a neurology center for mechanical thrombectomy, which revealed a complete occlusion of the right internal carotid artery. The procedure had to be halted due to blood extravasation at the internal carotid artery bifurcation to prevent further complications. An angio-CT examination of the cervical arteries exposed a soft atheromatous plaque on the right internal carotid artery, immediately after the bifurcation. Despite the patient having no significant medical history, blood tests indicated dyslipidemia. At the two-month follow-up, the patient remained hemiplegic, with mild dysphasia. Performing carotid and vertebral Doppler ultrasound before cervical spine surgery might be useful, whenever possible, to assess high-risk factors for ischemic events and avoid such debilitating complications.

Contralateral Middle Cerebral Artery Territory Infarction After Anterior Cervical Diskectomy and Fusion: A Case Report

CASE

A 70-year-old man underwent anterior cervical diskectomy and fusion (ACDF) of the C3/4 and C4/5 levels by a left-sided approach to address canal stenosis causing right arm weakness. Intraoperative neuromonitoring demonstrated an intermittent decrease in left-sided motor signals. Postoperatively, the patient experienced a right middle cerebral artery stroke. At the 1-year follow-up, right arm strength had improved, but there was persistent left-sided weakness due to stroke.

CONCLUSION

Although rare, possible intraoperative stroke should be considered when there are changes in motor or sensory evoked potentials. In addition, considerations should be given to pursue carotid stenosis screening in patients undergoing ACDF with known atherosclerosis or stroke history.

Ischemic stroke following neck dissection in the elderly

Objective:

Despite the known association of perioperative stroke with perioperative mortality, the prevalence of stroke following neck dissection in elderly patients remains unclear. This study compared the incidence of neck dissection-associated perioperative stroke in elderly and younger patients.

Materials and Methods:

Totally, 1057 patients receiving neck dissection for head and neck cancers between June 2012 and July 2016 were reviewed at a single center. The patients were divided into elderly (age ≥65 years, n = 177) and younger (age <65 years, n = 880) groups (mean age: 72.3 ± 6.1 and 53.3 ± 7.6, respectively). Patient, anthropometric, and clinical characteristics including diagnoses, comorbidities, length of hospitalization, and incidence of perioperative stroke were compared.

Results:

Younger patients were more likely to be male (P = 0.001) and to have received radiotherapy (P = 0.013). The prevalence of predisposing factors was higher in the elderly, including history of cerebral vascular accident (P = 0.002), hypertension (P < 0.001), diabetes (P < 0.001), and coronary artery disease (P < 0.001). Elderly patients also had longer hospitalizations (P < 0.001) for which previous radiotherapy was identified as a risk factor (adjusted odds ratio = 3.79, P = 0.0078). Postoperative ischemic stroke was diagnosed in two elderly patients (1.1%), whereas no ischemic strokes occurred in the younger group (P = 0.028). The overall incidence of perioperative stroke was 0.19%.

Conclusion:

The incidence of perioperative stroke was higher in the elderly than in the younger group. Furthermore, the prevalence of ischemic stroke in elderly patients associated with neck dissection was higher than that previously reported in the aged population after general head and neck operations, highlighting an increased risk of stroke in elderly patients receiving extensive neck surgery.

Postoperative stroke after anterior cervical discectomy and fusion in patients with carotid artery stenosis: a statewide database analysis

BACKGROUND

Carotid artery injury and stroke secondary to prolonged retraction remains an extremely rare complication in anterior cervical discectomy and fusion (ACDF). However, multiple studies have demonstrated that carotid artery retraction during the surgical approach may alter the normal blood flow, leading to a significant reduction in the cross-sectional area of the vessel. Others have suggested that dislodgment of atherosclerotic plaques following manipulation of the carotid artery can be a potential risk for intracranial embolus and stroke.

PURPOSE

We aimed to evaluate: (1) the incidence of postoperative stroke following ACDF and (2) incidence of other postoperative complications in a cohort of patients who had a diagnosis of carotid artery stenosis (CAS) versus those who did not.

PATIENT SAMPLE

This study utilized the Statewide Planning and Research Cooperative System database from January 1, 2009 to December 31, 2013. All patients who underwent (ACDF) and had a preoperative diagnosis of CAS were identified using the International Classification of Disease, ninth revision codes. Those who had a previous history of stroke were excluded. Patients who had CAS were propensity score matched to patients without history of CAS for demographics and Charlson/Deyo comorbidity scores.

OUTCOME MEASURES

Incidence of postoperative stroke and other complications were compared between the cohorts. The threshold for statistical significance was set at a p<.05. This study received no funding. The authors report no conflict of interests relevant to this study.

RESULTS

There were 34,975 patients who underwent an ACDF in the study time period. After excluding those under the age of 18 and with history of previous stroke, there were 61 patients who had CAS that were compared with a propensity-matched cohort. The CAS cohort had a significantly higher incidence of postoperative stroke during their hospitalization (6.6% vs 0%, p<.042). The CAS cohort also had higher rates of acute renal failure (27.9% vs 4.9%, p = .01) and sepsis (18% vs 4.9%, p = .023). There were no stroke related deaths.

CONCLUSIONS

Patients with CAS who underwent ACDF had a statistically significant greater incidence of developing a postoperative stroke. To the best of our knowledge, no previous study has evaluated the development of postoperative stroke in patients with CAS undergoing ACDF. Larger, multicenter studies are needed to estimate the true incidence of stroke in this specific patient population. However, our results may illustrate the importance of preoperative optimization, approach-selection, and postoperative stroke surveillance in patients with a history of CAS who undergoes ACDF.

Bithalamic Infarction (Artery of Percheron Occlusion) after Anterior Cervical Discectomy and Fusion

Bithalamic infarction resulting from occlusion of the artery of Percheron after cervical spine surgery is a rare pathological entity. Diagnosis and early detection are challenging. Prompt management may help to improve the outcome. We present a case of a 39-year-old male patient, smoker, diagnosed with multiple cervical disc herniations, who underwent Anterior Cervical Discectomy and Fusion (ACDF) for C3-C4, C4-C5, and C5-C6. During the 2-hour and 50-minute surgery, the patient was lying supine with his neck hyperextended. The intraoperative procedure was uneventful. During surgery, blood pressure ranged around 110 mmHg∖50 mmHg. At the end of surgery, the patient's recovery from general anesthesia was normal with no delaying or complication; on next the day, patient developed a sudden loss of consciousness. Urgent brain computed tomography (CT) was normal; two days later, follow-up CT and CT Angiography (CTA) revealed bilateral thalamic infarction with right vertebral artery occlusion from its origin. Intraoperative surgical manipulation, hypotensive anesthesia, and prolonged neck hyperextension might have contributed to stroke in this patient. ACDF carries a potential risk for posterior circulation stroke. Artery of Percheron infarction should be considered in the differential diagnosis of patients developing a sudden loss of consciousness after ACDF. Vertebral artery thrombosis should be taken into account as an important possible cause of embolism.

Manual preoperative tracheal retraction exercise decreases the occurrence of postoperative oropharyngeal dysphagia after anterior cervical discectomy and fusion

OBJECTIVE

Preoperative tracheal retraction exercise (TRE) to minimize the occurrence of postoperative oropharyngeal dysphagia after anterior cervical spine surgery.

METHODS

A total of 220 patients admitted for elective anterior cervical spine surgery from January 2013 to December 2014 were retrospectively reviewed. The patients were allocated into two groups: TRE group and control group (without TRE). Modified dysphagia scoring system (MDSS) was used for evaluating the presence and severity of dysphagia symptoms at 1 week and 1, 3, and 6 months after surgery. Demographics such as age, gender, smoking, type of procedure, number of levels operated, duration of surgery, intraoperative blood loss, and instrumentation were analyzed. The clinical outcomes in both groups were compared with Neck Disability Index (NDI), Visual Analogue Scale (VAS) for arm and neck pain, and Odom's criteria for global outcome.

RESULTS

In the first week postoperatively, 86 patients (39.1%) developed dysphagia, which decreased to 72 (32.7%), 5 (2.3%), and 4 (1.8%) after 1, 3, and 6 months, respectively. The patients who received the TRE prior to surgery had significantly better MDSS scores ( p = 0.032 for second-level, 0.022 for third-level, and 0.009 for fourth-level fusions) than control group patients who did not receive TRE at the first week of surgery. At the 1-month follow-up, the followed-up patients for second- to fourth-level fusions in the TRE group had improved MDSS scores than those in the control group ( p = 0.041 for second-level, 0.025 for third-level, and 0.0011 for fourth-level fusions). MDSS scores showed no significant difference between both the groups at 1 and 3 months postoperatively for single level anterior cervical fusion. NDI and VAS scores didn't yield any significant difference. Global outcome by Odom's criteria was 88.6%.

CONCLUSION

Preoperative TRE can significantly reduce the occurrence of postoperative dysphagia after ACDF surgery. During follow-up, the incidence of postoperative dysphagia was significantly lower and had resolved at 3 months in all patients.

Cerebral Thromboembolic Events During Anterior Cervical Spine Surgery: Retrospective Case Series Study With Diffusion-Weighted Magnetic Resonance Imaging Follow-up in the Immediate Postoperative Period

Objective

We evaluated the efficacy of diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting perioperative cerebral thromboembolic events after anterior cervical discectomy and fusion (ACDF).

Methods

This retrospective case series included 51 consecutive patients that underwent ACDF. To assess baseline presence of plaque or stenosis, all patients were assessed for risk factors of cerebrovascular events and underwent carotid ultrasound preoperatively and cerebral DW-MRI was performed in all patients postoperatively, with areas of high signal intensity interpreted as a cerebral thromboembolic event.

Results

One male patient who underwent a C4/5 ACDF had a focal diffusion abnormality on DW-MRI concerning for cerebral thromboembolic events in the right posterior cerebral artery territory. He remained asymptomatic and did not display related neurological symptoms, such as visual deficits.

Conclusion

Asymptomatic cerebral thromboembolic events can be detected by DW-MRI after ACDF. The incidence of such events remains very rare despite the direct manipulation and associated alteration of common carotid artery flow dynamics.

Perioperative Retinal Artery Occlusion: Incidence and Risk Factors in Spinal Fusion Surgery From the US National Inpatient Sample 1998-2013

BACKGROUND

Retinal artery occlusion (RAO) is a rare but devastating complication of spinal fusion surgery. We aimed to determine its incidence and associated risk factors.

METHODS

Hospitalizations involving spinal fusion surgery were identified by searching the National Inpatient Sample, a database of hospital discharges, from 1998 to 2013. RAO cases were identified using ICD-9-CM codes. Using the STROBE guidelines, postulated risk factors were chosen based on literature review and identified using ICD-9-CM codes. Multivariate logistic models with RAO as outcome, and risk factors, race, age, admission, and surgery type evaluated associations.

RESULTS

Of an estimated 4,784,275 spine fusions in the United States from 1998 to 2013, there were 363 (CI: 291-460) instances of RAO (0.76/10,000 spine fusions, CI: 0.61-0.96). Incidence ranged from 0.35/10,000 (CI: 0.11-1.73) in 2001-2002 to 1.29 (CI: 0.85-2.08) in 2012-2013, with no significant trend over time (P = 0.39). Most strongly associated with RAO were stroke, unidentified type (odds ratio, OR: 14.33, CI: 4.54-45.28, P < 0.001), diabetic retinopathy (DR) (OR: 7.00, CI: 1.18-41.66, P = 0.032), carotid stenosis (OR: 4.94, CI: 1.22-19.94, P = 0.025), aging (OR for age 71-80 years vs 41-50 years referent: 4.07, CI: 1.69-10.84, P = 0.002), and hyperlipidemia (OR: 2.96, CI: 1.85-4.73, P < 0.001). There was an association between RAO and transforaminal lumbar interbody fusion (OR: 2.95, CI: 1.29-6.75, P = 0.010). RAO was more likely to occur with spinal surgery performed urgently or emergently compared with being done electively (OR: 0.40, CI: 0.23-0.68, P < 0.001).

CONCLUSIONS

Patient-specific associations with RAO in spinal fusion include aging, carotid stenosis, DR, hyperlipidemia, stroke, and specific types of surgery. DR may serve as an observable biomarker of heightened risk of RAO in patients undergoing spine fusion.

Carotid Artery Injury in Anterior Cervical Spine Surgery: Multicenter Cohort Study and Literature Review

STUDY DESIGN

Retrospective study and literature review.

OBJECTIVE

To provide more comprehensive data about carotid artery injury (CAI) or cerebrovascular accident (CVA) related to anterior cervical spine surgery.

METHODS

We conducted a retrospective, multicenter, case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network. Medical records of 17 625 patients who went through cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were analyzed. Also, we performed a literature review using Medline and PubMed databases. The following terms were used alone, and in combination, to search for relevant articles: cervical, spine, surgery, complication, iatrogenic, carotid artery, injury, cerebrovascular accident, CVA, and carotid stenosis.

RESULTS

Among 17 625 patients that were analyzed, no cases were reported to experienced CAI or CVA after cervical spine surgery. Nevertheless, in our PubMed search we found 157 articles, but only 5 articles matched our study objective criteria; 2 cases were reported to present CAI and 3 cases presented CVA.

CONCLUSIONS

CAI and CVA related to anterior cervical spine surgeries are extremely rare. We were not able to find neither in our retrospective study nor in our literature research a correlation between the type or length of anterior cervical spine procedure with CVA or CAI complications. However, surgeons should be aware of the possibility of vascular complications and minimize intraoperative direct vascular manipulations or retraction. Preoperative screening for underlying vascular pathology and risk factors is also important.

Delayed cerebral infarct following anterior cervical diskectomy and fusion

Background:

Ischemic stroke following anterior cervical diskectomy and fusion (ACDF) is an exceedingly rare complication. There are only three previous cases focusing on this problem in the literature; here, we present the fourth case.

Case Description:

A patient, cared for at an outside institution, developed a delayed ischemic stroke 3 days following an ACDF. This complication was attributed to carotid manipulation precipitating vascular injury in the setting of multiple comorbid vascular and coagulopathic risk factors, including previously undiagnosed carotid atherosclerosis, a prior history of pulmonary embolus requiring Warfarin anticoagulation (held perioperatively), acute dehydration, and atrial fibrillation.

Conclusions:

This case demonstrates the importance of focused history and examination in appropriate patients prior to ACDF, with special consideration given to the significance of age, comorbidities including coagulopathy and arrhythmia, and potential underlying vascular disease as markers for increased risk of perioperative thrombotic stroke associated with carotid manipulation. Patients at higher risk warrant comprehensive preoperative assessment, including medical evaluation, carotid imaging, and consideration for alternative surgical approaches.

Somatosensory evoked potential monitoring detection of carotid compression during ACDF surgery in a patient with a vascularly isolated hemisphere

The authors report herein a case of anterior cervical discectomy and fusion (ACDF) surgery in which findings on somatosensory evoked potential (SSEP) monitoring led to the correction of carotid artery compression in a patient with a vascularly isolated hemisphere (no significant collateral blood vessels to the carotid artery territory). The amplitude of the cortical SSEP component to left ulnar nerve stimulation progressively decreased in multiple runs, but there were no changes in the cervicomedullary SSEP component to the same stimulus. When the lateral (right-sided) retractor was removed, the cortical SSEP component returned to baseline. The retraction was then intermittently relaxed during the rest of the operation, and the patient suffered no neurological morbidity. Magnetic resonance angiography demonstrated a vascularly isolated right hemisphere. During anterior cervical spine surgery, carotid artery compression by the retractor can cause hemispheric ischemia and infarction in patients with inadequate collateral circulation. The primary purpose of SSEP monitoring during ACDF surgery is to detect compromise of the dorsal column somatosensory pathways within the cervical spinal cord, but intraoperative SSEP monitoring can also detect hemispheric ischemia. Concurrent recording of cervicomedullary SSEPs can help differentiate cortical SSEP changes due to hemispheric ischemia from those due to compromise of the dorsal column pathways. If there are adverse changes in the cortical SSEPs but no changes in the cervicomedullary SSEPs, the possibility of hemispheric ischemia due to carotid artery compression by the retractor should be considered.

Postoperative complications of spine surgery

A variety of surgical approaches are available for the treatment of spine diseases. Complications can arise intraoperatively, in the immediate postoperative period, or in a delayed fashion. These complications may lead to severe or even permanent morbidity if left unrecognized and untreated [1-4]. Here we review a range of complications in the early postoperative period from more benign complications such as postoperative nausea and vomiting (PONV) to more feared complications leading to permanent loss of neurological function or death [5]. Perioperative pain management is covered in a separate review (Chapter 8).

Perioperative stroke in patients undergoing elective spinal surgery: a retrospective analysis using the Japanese diagnosis procedure combination database

BACKGROUND

Although a few studies on perioperative stroke following spinal surgery have been reported, differences in the incidence of perioperative stroke among various surgical procedures have not been determined. The purpose of this retrospective analysis was to investigate the incidence of perioperative stroke during hospitalization in patients undergoing elective spinal surgery, and to examine whether the incidence varied according to the surgical procedure.

METHODS

A retrospective analysis of data from the Diagnosis Procedure Combination database, a nationwide administrative impatient database in Japan, identified 167,106 patients who underwent elective spinal surgery during 2007-2012. Patient information extracted included age, sex, preoperative comorbidity, administration of blood transfusion, length of hospitalization, and type of hospital. Clinical outcomes included perioperative stroke during hospitalization, and in-hospital death.

RESULTS

The overall incidence of perioperative stroke was 0.22 % (371/167,106) during hospitalization. A logistic regression model fitted with a generalized estimating equation showed perioperative stroke was associated with advanced age, a history of cardiac disease, an academic institution, and resection of a spinal tumor. Patients who underwent resection of a spinal cord tumor (reference) had a higher risk of stroke compared with those undergoing discectomy (odds ratio (OR), 0.29; 95 % confidence interval (CI), 0.14-0.58; p = 0.001), decompression surgery (OR, 0.44; 95 % CI, 0.26-0.73; p = 0.001), or arthrodesis surgery (OR, 0.55; 95 % CI, 0.34-0.90); p = 0.02). Advanced age (≥80 years; OR, 5.66; 95 % CI, 3.10-10.34; p ≤ 0.001), history of cardiac disease (OR, 1.58; 95 % CI, 1.10-2.26; p = 0.01), diabetes (OR, 1.73; 95 % CI, 1.36-2.20; p ≤ 0.001), hypertension (OR, 1.53; 95 % CI, 1.18-1.98; p = 0.001), cervical spine surgery (OR, 1.44; 95 % CI, 1.09-1.90; p = 0.01), a teaching hospital (OR, 1.36; 95 % CI, 1.01-1.82; p = 0.04), and length of stay (OR, 1.008; 95 % CI, 1.005-1.010; p ≤ 0.001) were also risk factors for perioperative stroke.

CONCLUSIONS

Perioperative stroke occurred in 0.22 % of patients undergoing spinal surgery. Resection of a spinal cord tumor was associated with increased risk of perioperative stroke as well as advanced age, comorbidities at admission, cervical spine surgery, surgery in a teaching hospital, and length of stay.

Anterior Cervical Spine Surgery for Degenerative Disease: A Review

Anterior cervical spine surgery is an established surgical intervention for cervical degenerative disease and high success rate with excellent long-term outcomes have been reported. However, indications of surgical procedures for certain conditions are still controversial and severe complications to cause neurological dysfunction or deaths may occur. This review is focused mainly on five widely performed procedures by anterior approach for cervical degenerative disease; anterior cervical discectomy, anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, anterior cervical foraminotomy, and arthroplasty. Indications, procedures, outcomes, and complications of these surgeries are discussed.

Internal carotid artery dissection after anterior cervical disc replacement: first case report and literature review of vascular complications of the approach

We report the case of a 41-year-old woman who underwent cervical total disc replacement at C4C5 and C5C6 levels and fusion at C6C7 level through an anterior right-side approach. After anesthesia recovery, the patient presented left hemiparesia and facial palsy due to large right hemispheric stroke. Diffusion-weighted magnetic resonance imaging was performed as soon as the patient developed neurologic symptoms of stroke and revealed a right internal carotid artery dissection. Digital substraction angiography, endovascular stenting, angioplasty and thrombectomy were performed. Six months after treatment, clinical examination showed mild left-arm spasticity. To the best of our knowledge, only two cases of internal carotid artery stroke without dissection or thrombosis are reported. In conclusion, although vascular complications are rare after anterior cervical spine procedure, internal carotid artery dissection can occur. Suspected risk factors are prolonged retraction of the carotid artery and neck extension.

Postoperative cervical haematoma complicated by ipsilateral carotid thrombosis and aphasia after anterior cervical fusion: a case report

Hematoma alone is the most common vascular complication reported after anterior cervical decompression and fusion (ACDF). We present this case to report the occurrence of postoperative cervical hematoma complicated by ipsilateral carotid thrombosis and aphasia after an uncomplicated C4-6 ACDF. This is a case of a 65-year-old woman who underwent revision fusions of the C4-5 and C6-7 levels complicated by postoperative cervical hematoma and carotid thrombosis. The patient's history, clinical examination, imaging findings, and treatment are reported. The revision fusions were performed and deemed routine. Approximately eight hours later 200 mL of blood was evacuated from a postoperative cervical hematoma. The patient became unresponsive and disoriented a few hours after evacuating the hematoma. Computed tomography and magnetic resonance imaging of the brain were normal, but magnetic resonance angiography demonstrated total occlusion of the left carotid artery. Thrombectomy was performed and the patient was discharged without residual deficits. At the latest followup she is fully functional and asymptomatic in her neck. We suggest, after evacuating a cervical hematoma, an evaluation of the carotids be made with MRA or cerebral angiography, as this may demonstrate a clot before the patient develops symptoms.

Brown-Sequard-type myelopathy due to cervical disc herniation associated with severe carotid stenosis prompting rapid combined corpectomy and carotid endarterectomy under deep anticoagulant therapy

BACKGROUND CONTEXT

The risk of stroke because of carotid retraction during an anterior cervical spine surgery as well as the risk of bleeding complications after an anterior cervical corpectomy under deep anticoagulation and antiplatelet therapy is a surgical issue poorly addressed in the literature.

PURPOSE

To describe the feasibility and safety of a simultaneous carotid endarterectomy and anterior corpectomy and fusion under deep anticoagulation in a patient with a cervical spinal cord compression and a severe carotid artery stenosis.

STUDY DESIGN

Case report.

METHODS

The authors describe the case of a 79-year-old man who had a 1-month history of progressive pain in the neck and left arm, associated with progressive weakness in the left arm and leg. He also presented a history of coronaropathy and bilateral severe carotid stenosis for which he was receiving a regimen of antiplatelet therapy.

RESULTS

The cervical magnetic resonance imaging demonstrated a C4-C5 disc herniation migrating down to C5. His condition worsened rapidly during hospitalization prompting a rapid decompression. Given the necessity of a C5 corpectomy and the risk of stroke during anterior cervical spine surgery, it was therefore decided to undertake the surgical procedure under efficient anticoagulant and antiplatelet therapy. A combined endarterectomy and spinal decompression and fusion were then performed. The postoperative course was uneventful, and the patient recovered neurologically.

CONCLUSIONS

This case suggests that such a combined carotid endarterectomy and cervical corpectomy with fusion under anticoagulant and antiplatelet therapy is feasible. However, even if the unique clinical presentation of our patient led us to undertake such a surgical strategy, therapeutic decision in patients presenting with both severe carotid stenosis and cervical spinal cord compression should rely on a case-by-case analysis.

Vascular injury and complication in neurosurgical spine surgery

Vascular injury is an uncommon, but not rare complication of spine surgery. The consequence of vascular injury may be quite devastating, but its incidence can be reduced by understanding the mechanisms of injury. Properly managing vascular injury can reduce mortality and morbidity of patients. A review of the literature was conducted to provide an update on the etiology and management of vascular injury and complication in neurosurgical spine surgery. The vascular injuries were categorized according to each surgical procedure responsible for the injury, i.e., anterior screw fixation of the odontoid fracture, anterior cervical spine surgery, posterior C1-2 arthrodesis, posterior cervical spine surgery, anterolateral approach for thoracolumbar spine fracture, posterior thoracic spine surgery, scoliosis surgery, anterior lumbar interbody fusion (ALIF), lumbar disc arthroplasty, lumbar discectomy, and posterior lumbar spine surgery. The incidence, mechanisms of injury, and reparative measures were discussed for each surgical procedure. Detailed coverage was especially given to vascular injury associated with ALIF, which may have been underestimated. The accumulation of anatomical knowledge and advanced imaging studies has made complex spine surgery safer and more reliable. It is not clear, however, whether the incidence of vascular injury has been reduced significantly in all procedures of spine surgery. Emerging new techniques, such as microendoscopic discectomy and lumbar disc arthroplasty, seem to be promising, but we need to keep in mind their safety issues, including vascular injury and complication.

Cerebral Ischemia as an Apparent Complication of Anterior Cervical Discectomy in a Patient with an Incomplete Circle of Willis

A 58-yr-old patient sustained a cerebral ischemic injury in the distribution of the carotid artery ipsilateral to retraction during an anterior cervical discectomy. Relative hypotension was permitted during the anesthetic. Angiography revealed an anatomic variant of the circle of Willis that resulted in minimal collateralizaton of the left internal carotid artery territory. The combination of that vascular variant with relative hypotension and some degree of carotid compression appears to have resulted in clinically significant cerebral ischemia.

Iatrogenic carotid artery injury in neurosurgery

Iatrogenic carotid artery injury (CAI) results from various neurosurgical procedures. A review of the literature was conducted to provide an update on the management of this potentially devastating complication. Iatrogenic CAIs are categorized according to each diagnostic or therapeutic procedure responsible for the injury, i.e., anterior cervical spine surgery, central venous catheterization, chemical substances, chiropractic manipulation, diagnostic cerebral angiography, middle-ear surgery, percutaneous procedures for trigeminal neuralgia, radiation therapy, skull-base surgery, tracheostomy, and transsphenoidal surgery. The incidence, mechanisms of injury, diagnostic imaging modalities, and reparative procedures are discussed for each procedure. Iatrogenic CAI may be more prevalent than had previously been thought, mostly because of a heightened awareness on the part of physicians and the earlier detection of asymptomatic patients owing to sophisticated and less-invasive imaging modalities. Prevention is the best treatment for every iatrogenic injury, and it is expected that further accumulation of experience with and knowledge of iatrogenic CAI will result in further reduction of this complication. Although some CAIs, such as radiation-induced carotid artery stenosis, may not be preventable, earlier intervention before the patient becomes symptomatic may favorably alter the prognosis. Following the rapid development of endovascular techniques in recent years, surgically inaccessible lesions can be treated in a more reliable and safe manner than before.