Strategies for prevention and operative treatment of aortic lesions related to spinal interventions

Aortic Impingement in Displaced Traumatic Spine Fracture with Complete Spinal Cord Transection: A Case Report

Aortic impingement associated with traumatic thoracic spinal fractures is a rare and potentially lethal complication that creates management challenges in an already complex clinical problem. Traumatic aortic injury is one of the leading causes of death in blunt trauma. Magerl divided thoracic and lumbar fractures into 3 categories; the primary focus of this report, type C fractures, describes rotational injury and is one of the less common types, especially associated with aortic impingement as such. In this case, a young man was admitted following a near-fatal fall resulting in blunt force trauma to the midthoracic region. Emergency CT revealed a type C complete transection at the level of T11 and a grade I aortic injury. Definitive fixation of the spinal injury was delayed in favor of preventing further vascular injury by prioritizing the securing of hemodynamic stability. In traumatic thoracolumbar injuries, blunt traumatic aortic injury is often managed conservatively. However, blunt thoracic aortic injury is one of the leading causes of death from trauma, and each case requires its own case-by-case multidisciplinary management. In this occasion, management of the vascular insult was paramount to ensuring patient survival and favorable outcome.

Aortic injury in spine surgery……What a spine surgeon needs to know

Aortic injury is a rare, yet underreported and underestimated complication of spine surgery. Anatomical relation between the aorta and the spine changes under physiological (positional) as well as pathological (deformity) conditions, which puts the aorta at risk of injury during spine surgery. Clinical presentation of aortic injury ranges from asymptomatic perforation of the aorta to acute fatal bleeding. Although several diagnostic methods have been reported, CT-angiography remains an important diagnostic study. Several advancements in the open and the endovascular surgical management have been reported to be successfully used in the management of aortic injury following spine surgery. Management approach of malpositioned screws abutting the aorta is still controversial. Anatomical knowledge and understanding of the previously reported mechanisms of aortic injury are important to be integrated in the preoperative planning process. If the complication occurs, time-to- recognition and to-appropriate-management are important factors for predicting mortality. If unrecognized and untreated in the acutely injured patients, mortality can approach 100%.

Delayed Presentation of Thoracic Aortic Pseudoaneurysm Following Pedicle Screw Implantation: A Case Report

Background

Pedicle screw insertion has been known to have several complications even in the most skilled surgical hands. However, injury to the thoracic aorta during pedicle screw insertion is rare, delayed presentation secondary to pseudoaneurysm is even rarer, the pseudoaneurysm formation caused by a series of malpositioned pedicle screws has perhaps not been reported so far.

Case presentation

In this paper, we report here a case in which inadvertent injury to the thoracic aorta resulted in pseudoaneurysm, its manifestation was initially vague, resulting in a delayed diagnosis. Delayed aortic pseudoaneurysm or injury can be asymptomatic for a long time. Patients with renewed or continued back pain should alert orthopaedic surgeons regarding the possibility of pseudoaneurysms, regardless of the period that has elapsed after pedicle screw implantation.

Malpositioned pedicle screw in spine deformity surgery endangering the aorta: report of two cases, review of literature, and proposed management algorithm

STUDY DESIGN

Case reports and review of the literature with a proposed management algorithm.

OBJECTIVES

To report two cases of a potential vascular complication due to an incorrectly placed pedicle screw (PS) during spine deformity surgery. Relevant literature regarding the management of vascular complications is reviewed, and an evidence-based management algorithm is proposed. Aortic lesions represent a rare but potentially life-threatening complications with spine deformity and revision surgery, significantly increasing the risk. A management algorithm for an aortic lesion in the case of a malpositioned PS has not yet been published.

METHODS

Case 1: An 18-year-old female with proximal thoracic spinal non-instrumented fusion underwent a revision corrective procedure due to a progressive right-sided thoracolumbar compensatory curve. However, postoperative computed tomography (CT) performed to evaluate the position of the PS revealed malposition of the left T9 PS, which was abutting the descending aorta with CT angiography excluding the perforation of the aorta. Case 2: A 17-year-old male was scheduled for correction of Lenke 3-C-N adolescent idiopathic scoliosis. Postoperative routine evaluation with low-dose CT revealed a left T9 PS paravertebral malposition, and subsequent CTA demonstrated that the thread of the PS was in contact with the descending thoracic aorta and an unlikely hemodynamically significant vessel injury.

RESULTS

Successful removal of both malpositioned PS was performed. In the first case, a cardiovascular surgeon attended the operation if an urgent thoracotomy was needed, and in the second case, additional video-assisted thoracoscopic control of the aorta was performed during PS removal.

CONCLUSIONS

Preoperative imaging in spinal surgery is essential to avoid major vascular and other complications when placing PS, especially in thoracic deformities. When a potential major vessel complication emerges, an interdisciplinary approach and an appropriate management algorithm are mandatory to make the best clinical decisions.

LEVEL OF EVIDENCE

4.

Delayed presentation of infected common iliac artery pseudoaneurysm caused by malpositioned pedicle screw after minimally invasive scoliosis surgery

PURPOSE

To report delayed onset common iliac artery perforation and infected pseudoaneurysm caused by malpositioned pedicle screw after minimally invasive scoliosis surgery (MISS).

METHODS

A 21-year-old female was referred to our hospital with a 1-week history of abrupt right-sided low back pain, lower abdominal pain, and fever with a history of MISS using cannulated pedicle screws 18 months earlier. Paravertebral arterial erosion with pseudoaneurysm and retroperitoneal and paraspinal abscess were suspected.

RESULTS

We performed resection of the pseudoaneurysm, vascular repair of right common iliac artery by angioplasty with a bovine patch and removal of implant. At 6 months after the last surgery, she had no limitations or problems in her daily activities with no recurrence of low back pain, abdominal pain, or fever as well as without loss of deformity.

CONCLUSIONS

Our case showed that misplaced pedicle screws can cause potentially fatal complications, such as infected pseudoaneurysm, even in the late postoperative period.

Unstable thoracic spine fracture with aortic encroachment: A potentially fatal association and a suggested treatment

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The association of unstable spinal fractures and pending aortic injuries is a therapeutic dilemma.

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Inappropriate treatment can lead to catastrophic consequences.

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A multidisciplinary, case-by-case evaluation is mandatory.

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Vascular lesions must be treated first.

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We suggest “best but safest” procedure sequence: endovascular aortic repair and then posterior spinal cord reconstruction.

Background

The coexistence of an unstable spinal fracture with a pending aortic lesion is potentially catastrophic and a therapeutic challenge as to timing of treatment, assigning priorities and selecting the best approach.

Case report

A 41 year-old healthy male victim of bike accident. Imaging revealed a fracture of 6th and 7th thoracic vertebrae with a bone fragment in close proximity to the descending thoracic aorta. After consultation with spine/vascular surgeons and interventional radiologists it was decided to secure the potential aortic injury with an endovascular stent-graft followed by posterior vertebral instrumentation for fracture’s reduction.

Discussion/conclusion

A multi-specialists teamwork approach is mandatory. Vascular lesion is priority, followed by vertebral surgery. As to the treatment options, we suggest a “best but still safest” philosophy: endovascular repair and posterior spinal instrumentation should be considered first in the acute stage.

Anterior cage dislodgement in posterior lumbar interbody fusion: a review of 12 patients

OBJECTIVE Interbody fusion cages are widely used to achieve initial fixation and secure spinal fusion; however, there are certain technique-related complications. Although anterior cage dislodgement can cause major vascular injury, the incidence is extremely rare. Here, the authors performed a review of anterior cage dislodgement following posterior lumbar interbody fusion (PLIF) surgery. METHODS The authors retrospectively reviewed the cases of 4625 patients who had undergone PLIF at 6 institutions between December 2007 and March 2015. They investigated the incidence and causes of surgery-related anterior cage dislodgement, salvage mechanisms, and postoperative courses. RESULTS Anterior cage dislodgement occurred in 12 cases (0.26%), all of which were caused by technical errors. In 9 cases, excessive cage impaction resulted in dislodgement. In 2 cases, when the cage on the ipsilateral side was inserted, it interacted and pushed out the other cage on the opposite side. In 1 case, the cage was positioned in an extreme lateral and anterior part of the intervertebral disc space, and it postoperatively dislodged. In 3 cases, the cage was removed in the same operative field. In the remaining 9 cases, CT angiography was performed postoperatively to assess the relationship between the dislodged cage and large vessels. Dislodged cages were conservatively observed in 2 cases. In 7 cases, the cage was removed because it was touching or compressing large vessels, and an additional anterior approach was selected. In 2 patients, there was significant bleeding from an injured inferior vena cava. There were no further complications or sequelae associated with the dislodged cages during the follow-up period. CONCLUSIONS Although rare, iatrogenic anterior cage dislodgement following a PLIF can occur. The authors found that technical errors made by experienced spine surgeons were the main causes of this complication. To prevent dislodgement, the surgeon should be cautious when inserting the cage, avoiding excessive cage impaction and ensuring cage control. Once dislodgement occurs, the surgeons must immediately address this difficult complication. First, the possibility of a large vessel injury should be considered. If the patient's vital signs are stable, the surgeon should continue with the surgery without cage removal and perform CT angiography postoperatively to assess the cage location. Blind maneuvers should be avoided when the surgical site cannot be clearly viewed. When the cage compresses or touches the aortic artery or vena cava, it is better to remove the cage to avoid late-onset injury to major vessels. When the cage does not compress or touch vessels, its removal is controversial. The risk factors associated with performing another surgery should be evaluated on a case-by-case basis.

Delayed Presentation of Aortic Injury by a Thoracic Pedicle Screw

Delayed presentation of a thoracic aortic injury is an extremely rare complication after spine surgery. We report a case of delayed presentation of a thoracic aortic injury with a vertebral pedicle screw after posterior spinal surgery without periaortic hematoma, hemorrhage or pseudoaneurysm formation and review the relevant literature.

Endovascular repair of thoracic aortic injury after spinal instrumentation

Aortic injury after thoracic spinal instrumentation is a rare complication that carries significant potential morbidity and mortality if it is not appropriately managed. We report a patient successfully treated in an endovascular manner, thereby applying minimally invasive techniques to avoid the morbidity of open thoracotomy. Decreased short-term morbidity with the endovascular approach offers significant advantage over open repair, thereby omitting aortic cross-clamping, thoracotomy, and increased risk from the patient's comorbidities. An endovascular approach to this potentially devastating complication of thoracic spinal instrumentation can be both safe and effective in selected patients and not exclusively performed in cases of hemorrhage, hematoma, or pseudoaneurysm.

Novel posterior technique to temporize life-threatening hemorrhage after great vessel laceration during posterior osteotomy

PURPOSE

Great vessel injury during posterior 3-column osteotomy is rare, but potentially fatal. Literature review revealed limited data guiding spine surgeons during this major catastrophe. In this study our aim was first, to present our case of mortality; second, to discuss a novel technique that can be performed to temporize hemorrhage in a life-threatening situation where an iatrogenic great vessel injury occurs and hemodynamic stability cannot be achieved through usual means of hemostasis; third, a cadaveric study to determine if this novel technique is feasible.

METHODS

Three fresh cadavers including thoracic, lumbar, and pelvis were used. A thoraco-abdominal approach was used to access great vessels at the level of L3. The aorta and vena cava were identified and tagged. The cadavers were turned prone; a pedicle subtraction osteotomy was performed at the level of L3. A novel posterior peri-vertebral approach was used to reach the great vessels. The aorta and vena cava were occluded digitally with this approach and success confirmed visually through the thoraco-abdominal incision. Timing of the procedure and structures at risk were recorded.

RESULTS

In all three cadavers, we were able to successfully occlude the great vessels from a prone position. The average amount of time it took to digitally occlude the great vessels was less than a minute. Structures at risk included the L1 and L2 nerve roots, lumbosacral plexus, and the sympathetic trunk.

CONCLUSIONS

The posterior peri-vertebral approach can potentially be used by a spine surgeon during a life-threatening situation to temporarily occlude great vessel hemorrhage while waiting for the assistance of a vascular/trauma team.

Incidence and clinical significance of vascular encroachment resulting from freehand placement of pedicle screws in the thoracic and lumbar spine: analysis of 6816 consecutive screws

STUDY DESIGN

Retrospective case series.

OBJECTIVE

Evaluate the incidence and clinical significance of vascular encroachment resulting from freehand placement of pedicle screws in the thoracic and lumbosacral spine.

SUMMARY OF BACKGROUND DATA

Pedicle screws are routinely used to effectively stabilize all 3 columns of the spine but can be technically demanding to place in the setting of variable anatomy. There is a paucity of data regarding iatrogenic major vascular injuries during posterior instrumentation procedures.

METHODS

We retrospectively reviewed the records of all patients undergoing freehand pedicle screw placement without image guidance in the thoracic or lumbar spine during a 7-year period. The incidence and extent of vascular encroachment by a pedicle screw was determined by review of routine postoperative computed tomographic scans obtained within 24 hours of all surgical procedures. Vascular encroachment was defined as a pedicle screw that was touching or deforming the wall of a major vessel.

RESULTS

A total of 964 patients received 6816 freehand-placed pedicle screws in the thoracolumbar spine. Fifteen (0.22%) screws that encroached a major vascular structure were identified. Ten (0.29%) thoracic pedicle screws encroached on the aorta, 4 (0.14%) lumbar screws on the common iliac vein, and 1 S1 screw (0.19%) on the internal iliac vein. In consultation with vascular surgery, it was determined whether revision surgery and the technique/approach for the revision procedure should be recommended. Two (0.21%) patients required revision surgery to remove the encroaching pedicle screw (T5 and T8) due to concern for vascular injury. Both patients were asymptomatic and recovered without further complications after revision surgery.

CONCLUSION

Vascular encroachment of major vessels occurs rarely in the setting of freehand pedicle screw placement in the thoracolumbar spine. Although rare, delayed vascular injury from errant pedicle screw placement has been reported in the literature. The aorta seems to be the vessel at the highest risk of injury. Routine intraoperative or postoperative computed tomographic scanning allows for early identification of pedicle screws encroaching on vascular structures thereby facilitating early revision surgery.

LEVEL OF EVIDENCE

4.

Aortic dissection associated with penetration of a spinal pedicle screw: a case report and review of the literature

A 30-year-old male underwent a corrective posterior instrumented spinal fusion for scoliosis. Six years later, he was found to have an aortic dissection after aortic penetration of a spinal pedicle screw. We review the literature, including diagnostic modalities, and treatment decision-making for this unusual complication.

An endovascular treatment of a thoracic aortic injury caused by a misplaced pedicle screw: Case report and review of the literature

Aortic injuries are devastating complications after spinal surgery. We here would like to share our experience with a successful endovascular treatment of an iatrogenic thoracic aortic injury caused by misplaced pedicle screw after spinal surgery. A patient underwent posterior spinal surgery for L1 burst fracture was transferred to our department for instrumentation removal. An iatrogenic thoracic aortic injury at T11 level caused by a pedicle screw was recognized after routine CT scans. Complete screw extraction and instrumentation removal were performed after the placement of a thoracic aortic stent graft covering the injured region. The patient had an uneventful postoperative period and no complications were observed in the 1 and 12-month follow-up by contrast-enhanced CT scans. For the delayed thoracic aortic injuries which usually were usually shown on CT scans as pseudoaneurysm or penetration of the aorta, stent graft implantation would provide a preferred solution with high-effectiveness, low-invasiveness and fewer complications compared with conventional open surgery.

Spinal screw penetration of the aorta

Aortic injury is a complication of spinal instrumentation with treatment challenges, especially with hardware infection. We present two cases of spinal screws penetrating the descending thoracic aorta (DTA). Case 1 had pain after T6-T7 fusion with screw penetration of the DTA causing pseudoaneurysm. Case 2 had perforation of the DTA by a T4 screw with infected pseudoaneurysm. Neither was an endovascular candidate and both underwent open repair. Although endovascular approaches have benefits in aortic aneurysm repair, the techniques of open thoracic aortic repair remain relevant.

Variation of the position of the aorta relative to a kyphotic thoracic spine: safety margin for pedicle screw placement in the adult Japanese population

STUDY DESIGN

An analysis of computed tomography images of the spine in adult Japanese patients.

OBJECTIVE

To evaluate the variation of the position of the aorta relative to a spine with a thoracic kyphotic angle and to verify the safety margin for transpedicular screw fixation.

SUMMARY OF BACKGROUND DATA

Recent studies have suggested that the aorta is positioned more laterally and posteriorly in patients with idiopathic scoliosis than in normal patients; however, variation of the position of the aorta in thoracic sagittal alignment has not been performed.

METHODS

T4-T12 vertebrae were studied using computer tomography images in 58 Japanese patients (aged 31-90 years) with normal coronal alignment of the spine. Pedicle diameter, pedicle length, chord length, closest distance from the aorta, and pedicle-aorta angle (PAA) were evaluated using a Mann-Whitney U test and Spearman rank correlation analysis.

RESULTS

Pedicle diameter showed an increase in size from T4 (4.7 mm) to T12 (8.2 mm), pedicle length had an almost constant size of about 20 mm, and chord length increased from T4 (37.7 mm) to T12 (47.2 mm). Closest distance from the aorta decreased from T4 (29.6 mm) to T6 (24.6 mm) and then increased to T12 (49.3 mm). PAA increased from T4 (31.5°) to T6 (38.6°) and then decreased to T12 (5.0°). Sagittal curvature showed a correlation with PAA, with an increasing sagittal thoracic Cobb angle related to decreases in PAA at the T5 (r = -0.31, P = 0.034), T6 (r = -0.37, P = 0.008), and T7 (r = -0.29, P = 0.036) levels.

CONCLUSION

The descending aorta is positioned more medially at the T5, T6, and T7 levels in patients with a kyphotic spine. These spatial relationships should be considered when planning pedicle screw insertion for a kyphotic spine.

Combined endovascular and neurosurgical approach to the removal of an intraaortic pedicle screw

Iatrogenic aortic injuries are a potentially devastating complication of spine surgery. In instrumented cases, injuries may occur in the perioperative period due to iatrogenic vessel injury, or they may occur years later as prominent implants erode or penetrate major vessels. The authors present a case of a 71-year-old man in whom a thoracic pedicle screw was found perforating the thoracic aorta during routine follow-up 6 months after surgery. Due to the risk of future complications, the screw was removed while simultaneously delivering an endovascular aortic stent to gain vascular control. Surgical considerations and potential technical limitations are discussed.

Vascular injury in thoracolumbar spinal surgeries and role of angiography in early diagnosis and management

STUDY DESIGN

A retrospective outcomes study.

OBJECTIVE

To stress on the importance of early diagnosis with the help of angiography and proper treatment of vascular injuries occurring during thoracolumbar surgeries and to report our results.

SUMMARY OF BACKGROUND DATA

Vascular injury is a rare but dangerous complication that can develop during thoracolumbar surgeries and if not treated properly then it can lead to severe complications including the death of the patient.

METHODS

The patients included in this study were the ones who were suspected to have a possible vascular injury after a thoracolumbar surgery. Contrast enhanced computed tomography was performed for patients having clinical signs suggesting vascular injury. Among these patients, who were suspected to have active bleeding and major vessel injury on computed tomography were further subjected to angiography.

RESULTS

Of the 10 cases included in the study, vascular injury was identified to be arterial in origin in 8 cases and venous in 3 cases. Among the 8 cases of identified arterial injury, angiography was performed in 4 cases, of which 3 were found to have active bleeding and were subjected to immediate intervention. Of the 4 cases in which angiography was not performed, 3 of them expired at variable postoperative periods. Complications developed in total 5 cases including 3 cases of mortality, 1 case of infection, and 1 case of cauda equina syndrome.

CONCLUSIONS

The vascular injuries during thoracolumbar spinal surgeries need immediate and aggressive treatment. In arterial injuries, we can prevent serious consequences by subjecting the patient to an angiography as early as possible followed by a therapeutic embolization. In contrast, for venous injuries if hemostasis has been confirmed, then an immediate intervention may not be always required.