Iatrogenic Vascular Injury Research Articles

Relationship Between the Middle Genicular Artery and the Posterior Structures of the Knee: A Cadaveric Study.

Background:The middle genicular artery (MGA) is responsible for the blood supply to the cruciate ligaments and synovial tissue. Traumatic sports injuries and surgical procedures (open and arthroscopic) can cause vascular damage. Little attention has been devoted to establish safe parameters for the MGA.Purpose:To investigate the anatomy of the MGA and its relation to the posterior structures of the knees, mainly the posterior capsule and femoral condyles, and to establish safe parameters to avoid harming the MGA.Study Design:Descriptive laboratory study.Methods:Dissection of the MGA was performed in 16 fresh, unpaired adult human cadaveric knees with no macroscopic degenerative or traumatic changes and no previous surgeries. The specimens were meticulously evaluated with emphasis on preservation of the MGA. The distances from the MGA to the medial and lateral femoral condyles were measured. The Mann-Whitney test was used for statistical analysis.Results:In all specimens, the MGA emerged from the anterior aspect of the popliteal artery, distal to the superior genicular arteries, and had a short distal trajectory toward the posterior capsule where it entered proximal to the oblique popliteal ligament. The artery lay in the midportion between the condyles. The distance between the posterior aspect of the tibia and the point of entry of the MGA into the posterior joint capsule was 23.8 ± 7.3 mm (range, 14.72-35.68 mm). There was no correlation between an individual’s height and the distance of the entrance point of the MGA into the posterior joint capsule to the posterior superior corner of the tibia.Conclusion:The middle genicular artery lies in the midportion between the medial and lateral femoral condyles.Clinical Relevance:This knowledge is important for the preservation of the blood supply during posterior knee surgical procedures and to settle a secure distance between the posterior aspect of the tibia and the MGA input. This could decrease and prevent iatrogenic vascular injury risk to the MGA.

Closure Devices for Iatrogenic Thoraco-Cervical Vascular Injuries

IntroductionThe unintentional arterial placement of a central venous line can have catastrophic complications. The purpose of this systematic review is to assess and analyse the available evidence regarding the use of the various vascular closure devices (VCDs) for the management of iatrogenic thoraco-cervical arterial injuries (ITCAI).MethodsA systematic review was performed according to PRISMA guidelines.ResultsThirty-two relevant case series and case reports were identified with a total of 69 patients having being studied. In the majority of the studies, plug-based VCDs were used (81%) followed by suture-based devices (19%). The majority of studies reported successful outcomes from the use of VCDs in terms of achieving immediate haemostasis without any acute complications. Long-term follow-up data were only available in nine studies with only one case of carotid pseudoaneurysm being reported after 1-month post-procedure. All other cases had no reported long-term complications. Five studies performed direct or indirect comparisons between VCDs and other treatments (open surgery or stent grafting) suggesting no significant differences in safety or effectiveness.ConclusionAlthough there is limited evidence, VCDs appear to be safe and effective for the management of ITCAIs. Further research is warranted regarding the effectiveness of this approach in comparison to surgery and in order to identify those patients who are more likely to benefit from this minimally invasive approach.

Review of Surgical Iatrogenic Vascular Injuries and Their Management

Review of Surgical Iatrogenic Vascular Injuries and Their Management

Anatomical differences in patients with lumbosacral transitional vertebrae and implications for minimally invasive spine surgery.

OBJECTIVE The objective of this study was to investigate the neurovascular and anatomical differences in patients with lumbosacral transitional vertebrae (LSTV) and the associated risk of neurovascular injury in minimally invasive spine surgery. METHODS The authors performed a retrospective study of CT and MR images of the lumbar spine obtained at their institution between 2010 and 2014. The following characteristics were evaluated: level of the iliac crest in relation to the L4-5 disc space, union level of the iliac veins and arteries in relation to the L4-5 disc space, distribution of the iliac veins and inferior vena cava according to the different Moro zones (A, I, II, III, IV, P) at the L4-5 disc space, and the location of the psoas muscle at the L4-5 disc space. The findings were compared with findings on images obtained in 28 age- and sex-matched patients without LSTV who underwent imaging studies during the same time period. RESULTS Twenty-eight patients (12 male, 16 female) with LSTV and the required imaging studies were identified; 28 age- and sex-matched patients who had undergone CT and MRI studies of the thoracic and lumbar spine imaging but did not have LSTV were selected for comparison (control group). The mean ages of the patients in the LSTV group and the control group were 52 and 49 years, respectively. The iliac crest was located at a mean distance of 12 mm above the L4-5 disc space in the LSTV group and 4 mm below the L4-5 disc space in the controls. The iliac vein union was located at a mean distance of 8 mm above the L4-5 disc space in the LSTV group and 2.7 mm below the L4-5 disc space in the controls. The iliac artery bifurcation was located at a mean distance of 23 mm above the L4-5 disc space in the LSTV group and 11 mm below the L4-5 disc space in controls. In patients with LSTV, the distribution of iliac vein locations was as follows: Zone A, 7.1%; Zone I only, 78.6%; Zone I encroaching into Zone II, 7.1%; and Zone II only, 7.1%. In the control group, the distribution was as follows: Zone A only, 17.9%; Zone A encroaching into Zone I, 75%; and Zone I only, 7.1%. There were no iliac vessels in Zone II in the control group. The psoas muscle was found to be rising away laterally and anteriorly from the vertebral body more often in patients with LSTV, resulting in the iliac veins being found in the "safe zone" only 14% of the time, greatly increasing the risk of vascular injury. CONCLUSIONS In patients with LSTV, the iliac crest is more likely to be above the L4-5 disc space, which increases the technical challenges of a lateral approach. The location of the psoas muscle rising away laterally and ventrally in patients with LSTV compared with controls and with the union of the iliac veins occurring more often above the L4-5 disc space increases the risk for iatrogenic vascular injury at the L4-5 level in this patient population.

Neurological outcomes following iatrogenic vascular injury during posterior atlanto-axial instrumentation

BackgroundIatrogenic vascular injury is a feared complication of posterior atlanto-axial instrumentation. A better understanding of clinical outcome and management options following this injury will allow surgeons to better care for these patients. The object of the study was to systematically review the neurologic outcomes after iatrogenic vascular injury during atlanto-axial posterior instrumentation. MethodsWe performed a systematic review of the Medline database following PRISMA guidelines. In our analysis, we included any retrospective cohort studies, prospective cohort studies, case reports, cases series, or systematic reviews with patients who had undergone posterior atlanto-axial fusion via screw rod constructs (SRC) or transarticular screws (TAS) that reported a patient with an injury to an arterial vessel directly attributable to the surgical procedure. ResultsSixty cases of vascular injury were reported in 2078 (2.9%) patients over 27 publications. The average age for this patient population was 55.7+/−17.9. Vascular injury following posterior C1/2 instrumentation resulted in ipsilateral stroke in 10.0% (n=6/60) and non-persistent neurologic deficit in 6.7% (n=4/60) of cases with the deficit being permanent (not including death) in 1.7% (n=1/60) of cases. Four patients (6.7%) died. Arteriovenous fistula or pseudoaneurysm occurred in 8.3% (n=5/60) and 3.3% (n=2/60) of cases, respectively. Eight patients (13.3%) underwent endovascular repair of the injury with no permanent deficit. ConclusionNeurological morbidity after iatrogenic vascular injury during posterior C1/2 fixation is higher than previously reported in literature. Some patients may benefit from endovascular treatment. Surgeons should be aware of normal and anomalous vertebral artery anatomy to avoid this potentially catastrophic complication.

Neurological Outcomes following Iatrogenic Vascular Injury during Posterior Atlanto-axial Instrumented Fusion

Introduction Iatrogenic vascular injury is a feared complication of posterior atlanto-axial instrumented fusion. A better understanding of clinical course following this injury will allow surgeons to better care for these patients. The object of the study was to systematically review the neurologic outcomes after iatrogenic vascular injury during atlanto-axial posterior instrumented fusion. Methods A systematic review of the PubMed database was performed, following the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The extracted data was recorded in an excel spreadsheet. To be included, the patients must have undergone fusion of the C1/C2 joint using posterior instrumentation with injury to an arterial vessel directly attributable to the surgical procedure. Results 86 incidences of vascular injury were found in 41 articles with 11200 patients. The average age of included patients was 46.4 +/− 24.1 for the screw rod construct (SRC) group and 36.2 +/− 28.2 for the transarticular screw (TAS) group. Vascular injury in SRC cases resulted in ipsilateral stroke in 15.9% ( n = 7/44) of patients and neurologic deficit in 22.7% ( n = 10/44) of patients with a permanent neurologic deficit occurring in 11.4% ( n = 5/44) of patients. Vascular injury following TAS fixation resulted in ipsilateral stroke in 11.9% of cases ( n = 5/42) and neurologic deficit in 23.8% of cases with the deficit being permanent in 9.5% ( n = 4/42) of cases. Death was the result of injury in 9.1% ( n = 4/44) of SRC cases and 7.1% ( n = 3/42) of TAS cases. Conclusions Neurological morbidity after iatrogenic vascular injury during posterior C1/2 fixation is higher than previously reported in literature. There has been no large-volume studies aimed at identifying a rate of neurologic complications after iatrogenic injury. Surgeons should be aware of the normal and anomalous vertebral artery anatomy to avoid this potentially catastrophic injury.

Injury to the Obturator Artery During Periacetabular Osteotomy: A Case Report.

We describe a middle-aged woman who had undergone periacetabular osteotomy (PAO) on both hips successively within a two-year period. Although the first PAO was successfully performed on the right hip without any complications, injury to the obturator artery occurred during the subsequent PAO on the left hip. In this case, the obturator artery seemed to be injured at the medial base of the iliopectineal eminence during osteotomy. PAO has been employed as a reconstructive surgery for acetabular dysplasia. However, given the proximity of intrapelvic vascular structures, there is a risk of iatrogenic vascular injury.

Endovascular Management of Iatrogenic Vascular Injury in the Craniocervical Region.

To evaluate iatrogenic vascular injuries in the craniocervical region and their endovascular management. Twenty-one patients (9 women, 12 men) with a mean age of 53.6 years (range 16-87 years), who underwent endovascular embolization for iatrogenic vascular injury in the craniocervical region between December 2000 and October 2015, were included in this retrospective study. Types of iatrogenic injuries, etiologies that caused these injuries and details of endovascular managements were reported. The etiologies of the vascular injuries were as follows: transsphenoidal surgery (n=9), skull-base surgery (n=2), cholesteatoma surgery (n=1), tracheostomy (n=2), central venous catheterization (n=2), oropharyngeal tumor operation (n=1), endovascular treatment of internal carotid artery (ICA) stenosis (n=1), suprasellar epidermoid tumor operation (n=1), sphenoid sinus tumor surgery (n=1), and speech prosthesis device placement (n=1). The types of vascular injuries diagnosed at the time of angiography were; 2 occlusions, 2 stenoses, 2 dissections, 1 carotid cavernous fistula, 8 artery rupture with extravasation, and 9 pseudoaneurysms. Endovascular management of these vascular injuries were; parent artery occlusion (PAO) (n=15), aneurysm occlusion (n=3), covered stent (n=1) and conservative management (n=2). All patients except two were successfully treated. No patient had bleeding within a 30-day period after angiography. Long-term follow-up was available in all patients without occurrence of re-bleeding. One patient died due to complications related to primary vascular injury. Although iatrogenic vascular injuries are rare, early diagnosis and management may be lifesaving. Endovascular techniques are reliable and safe in most of the patients.

Morphometric Analysis of Lumbar Disc Space in the Turkish Population and Safe Discectomy Distance in Lumbar Disc Surgery.

Lumbar discectomy is a common surgical intervention in neurosurgical practice. Iatrogenic vascular injury during this surgery is a rare, but serious complication. In this study, our aim was to review the average safe depth of discectomy for both sexes. This study involved a total of 56 patients between 21 and 79 years old (28 male and 28 female) who had no surgical pathology as documented by lumbar magnetic resonance imaging study. Measurements at L3-4, L4-5, and L5-S1 were performed for both sexes as follows: 1 < sup > st < /sup > measurement, from the furthest lateral part of the dura to the end of the disc (right-left); 2 < sup > nd < /sup > measurement, the anteroposterior length of the cross-section passing through the midline of the disc; 3rd measurement; from the furthest lateral part of the dura to the furthest lateral part of the disc (right-left); 4th measurement, the length from right to left of the cross-section passing through the midline of the disc. Measurement 1 at L3-4, L4-5, and L5-S1, this value was estimated to be 35.9 and 36.7 mm, 35.9 and 36.9, and 34 and 34.9 mm in the right and left sides respectively, for female subjects. The corresponding values for males were 41.4 and 42.1, 40.6 and 40.9, and 37.4 and 37.7 mm at L3-4, L4-5, and L5-S1, respectively. Measurement 3 in L3-4, L4-5, and L5-S1 disc spaces on the right and left sides in female subjects were 14.8 and 16.3 mm, 15.7 and 17.2 mm, and 14.9 and 17.1 mm, respectively, with corresponding figures of 18.6 and 19.5, 19.7 and 20.6, and 18.2 and 18.6 mm among male participants. Measurement 2 and 4 in females for L3-4, L4-5, and L5-S1 were 38.4 and 52.3 mm, 38.9 and 53.4 mm, and 37 and 51.8 mm, respectively. The corresponding figures for males were 43.2 and 57.6 mm, 43.2 and 58.9 mm, and 40.1 and 56.7 mm, respectively. Determination of the safe discectomy depth in both males and females, as well as the use of marking disc punches to indicate the safe margins may help clinicians to avoid this unwanted complication.

Iatrogenic iliac arteriovenous fistula with aortic pseudoaneurysm formation post lumbar (L4-L5) laminectomy and pedicular screw fixation.

Nowadays lumbar laminectomy is a common surgery in daily practice and a very safe procedure, but it can result in sudden life threatening though infrequent vascular complications with greater than 50% mortality [1]. Such events usually require immediate intervention, so it is essential that anesthesiologists and surgeons be aware of this potential complication, its manifestation and treatment. The incidence of iatrogenic vascular complications in lumbar spine surgery is reported to be 0.01%-0.17% [1]. Although reported cases are few, unrecognised events are more than expected. However when one such event does occur, it can cause fatality in an otherwise healthy patient. We present a case of a 55-years-old male, American Society of Anesthesiologists physical status I with low backache since 10 years, underwent laminectomy and screw fixation for the same. On the ninth postoperative day he started developing right lower limb swelling associated with pain. Deep vein thrombosis was ruled out on venous doppler. On postoperative day 15, he started developing dyspnea, and generalized edema. Abdominal bruit was present and neck veins were engorged. On postoperative day 16, facial edema increased and hypotension developed. CT angiogram of chest and abdomen revealed distal right common iliac artery fistulous communication with common iliac vein with prominent inferior vena cava and hepatic vein, pseudo-aneurysm arising from site of fistula (4.2 × 3.8 × 3.1 cc), neck of aneurysm measuring 18.5 mm (Fig. 1). CT chest showed bilateral pleural effusion with ground glass opacities. Emergency aneurysm repair was done on the same day. Postoperatively he was shifted to the surgical intensive care unit for elective ventilation and monitoring due to massive fluid shifts intra-operatively and massive hemorrhage. He was later hemodynamically stable and kept in intensive care unit for 3 more days and subsequently shifted to ward on postoperative day 4. Further course in ward was uneventful and the patient was discharged on postoperative day 7. Fig. 1 (A) Three dimensional computerized tomography reconstruction shows right common iliac arteriovenous fistula with pseudoaneurysm (Arrow). (B) Computerized tomography Angiogram shows a right common iliac arteriovenous fistula with pseudo-aneurysm (Arrow). ... The L4-5 disc space is the most common site for a herniation of intervertebral disc [2]. Bifurcation of the aorta and inferior vena cava lies just anterior to this disc space, separated from it only by the anterior spinal ligament. The pathogenesis of iatrogenic vascular injury after spinal injury relates to the anatomical complexity of the aortic bifurcation and inferior vena cava confluence occurring at or below L4. They may present immediately in the intraoperative period or remain subclinical for days to years [3]. Bleeding from the wound is not a reliable sign as the self-sealing effect of the anterior annulus fibrosus and anterior longitudinal ligament may prevent any bleeding to be seen posteriorly. These tissues are tough and elastic, leading to blood leakage in the retroperitoneal space rather than the operating field. Signs and symptoms are equally wide ranging and include intra-operative and postoperative hypotension, associated fall in hematocrit, acute ischemia, distal pulse deficit, bruit, thrill, pulsatile abdominal mass, abdominal pain, expanding hematoma, limb edema and non-healing wounds. As the arterial injury drain directly into the low pressure venous system, hemorrhage is an uncommon presentation with arteriovenous fistula and hence it becomes very difficult to identify such injuries. An arteriovenous fistula should be suspected in a patient with a history of lower lumbar disc surgery followed by progressive swelling of a lower limb and associated bruit [4]. Thus, a high index of suspicion is needed amongst anesthesiologists given the rarity of complications and wide range of presentations.

Right Hepatic Artery: A Cadaver Investigation and Its Clinical Significance.

The right hepatic artery is an end artery and contributes sole arterial supply to right lobe of the liver. Misinterpretation of normal anatomy and anatomical variations of the right hepatic artery contribute to the major intraoperative mishaps and complications in hepatobiliary surgery. The frequency of inadvertent or iatrogenic hepatobiliary vascular injury rises with the event of an aberrant anatomy. This descriptive study was carried out to document the normal anatomy and different variations of right hepatic artery to contribute to existing knowledge of right hepatic artery to improve surgical safety. This study conducted on 60 cadavers revealed aberrant replaced right hepatic artery in 18.3% and aberrant accessory right hepatic artery in 3.4%. Considering the course, the right hepatic artery ran outside Calot's triangle in 5% of cases and caterpillar hump right hepatic artery was seen in 13.3% of cases. The right hepatic artery (normal and aberrant) crossed anteriorly to the common hepatic duct in 8.3% and posteriorly to it in 71.6%. It has posterior relations with the common bile duct in 16.7% while in 3.4% it did not cross the common hepatic duct or common bile duct. The knowledge of such anomalies is important since their awareness will decrease morbidity and help to keep away from a number of surgical complications.

Iatrogenic vascular injuries during arthroplasty of the hip.

Vascular injuries during total hip arthroplasty (THA) are rare but when they occur, have serious consequences. These have traditionally been managed with open exploration and repair, but more recently there has been a trend towards percutaneous endovascular management. We performed a systematic review of the literature to assess if this change in trend has led to an improvement in the overall reported rates of morbidity and mortality during the last 22 years in comparison with the reviews of the literature published previously. We found a total of 61 articles describing 138 vascular injuries in 124 patients. Injuries because of a laceration were the most prevalent (n = 51, 44%) and the most common presenting feature, when recorded, was bleeding (n = 41, 53.3%). Delay in diagnosis was associated with the type of vascular lesion (p < 0.001) and the clinical presentation (p = 0.002). Open exploration and repair was the most common form of management, however percutaneous endovascular intervention was used in one third of the injuries and more constantly during the last 13 years. The main overall reported complications included death (n = 9, 7.3%), amputation (n = 2, 1.6%), and persistent ischaemia (n = 9, 7.3%). When compared with previous reviews there was a similar rate of mortality but lower rates of amputation and permanent disability, especially in patients managed by endovascular strategies.

The terminal branches of the medial femoral circumflex artery: the arterial supply of the femoral head.

This study investigates and defines the topographic anatomy of the medial femoral circumflex artery (MFCA) terminal branches supplying the femoral head (FH). Gross dissection of 14 fresh-frozen cadaveric hips was undertaken to determine the extra and intracapsular course of the MFCA's terminal branches. A constant branch arising from the transverse MFCA (inferior retinacular artery; IRA) penetrates the capsule at the level of the anteroinferior neck, then courses obliquely within the fibrous prolongation of the capsule wall (inferior retinacula of Weitbrecht), elevated from the neck, to the posteroinferior femoral head-neck junction. This vessel has a mean of five (three to nine) terminal branches, of which the majority penetrate posteriorly. Branches from the ascending MFCA entered the femoral capsular attachment posteriorly, running deep to the synovium, through the neck, and terminating in two branches. The deep MFCA penetrates the posterosuperior femoral capsular. Once intracapsular, it divides into a mean of six (four to nine) terminal branches running deep to the synovium, within the superior retinacula of Weitbrecht of which 80% are posterior. Our study defines the exact anatomical location of the vessels, arising from the MFCA and supplying the FH. The IRA is in an elevated position from the femoral neck and may be protected from injury during fracture of the femoral neck. We present vascular 'danger zones' that may help avoid iatrogenic vascular injury during surgical interventions about the hip.

Covered stents for exclusion of iatrogenic common carotid artery–internal jugular vein fistula and brachiocephalic artery pseudoaneurysm

Covered stents have rarely been used in neuroendovascular procedures. We report the case of a 74-year-old woman with a complex iatrogenic vascular injury from attempted insertion of a hemodialysis catheter:...

Iatrogenic urinary tract injuries: etiology, diagnosis, and management.

Iatrogenic injury to the urinary tract, including the kidneys, ureters, bladder, and urethra, is a potential complication of surgical procedures performed in or around the retroperitoneal abdominal space or pelvis. While both diagnostic and interventional radiologists often play a central and decisive role in the identification and initial management of a variety of iatrogenic injuries, discussions of these injuries are often directed toward specialists such as urologists, obstetricians, gynecologists, and general surgeons whose procedures are most often implicated in iatrogenic urinary tract injuries. Interventional radiologic procedures can also be a source of an iatrogenic urinary tract injury. This review describes the clinical presentation, risk factors, imaging findings, and management of iatrogenic renal vascular and urinary tract injuries, as well as the radiologist's role in the diagnosis, treatment, and cause of these injuries.

Iatrogenic percutaneous vascular injuries: clinical presentation, imaging, and management.

Vascular interventional radiology procedures are relatively safe compared with analogous surgical procedures, with overall major complication rates of less than 1%. However, major vascular injuries resulting from these procedures may lead to significant morbidity and mortality. This review will discuss the etiology, clinical presentation, diagnosis, and management of vascular complications related to percutaneous vascular interventions. Early recognition of these complications and familiarity with treatment options are essential skills for the interventional radiologist.

A twelve-year report of iatrogenic vascular injuries: Is vascular centralisation safe?

A twelve-year report of iatrogenic vascular injuries: Is vascular centralisation safe?

Ultrasound-guided surgical treatment for ulnar nerve entrapment: A cadaver study

Several open and endoscopic techniques for the surgical treatment of ulnar nerve entrapment at the elbow (cubital tunnel syndrome) have been described that provide decompression with or without anterior transposition. Based on our experience with US-guided decompression for carpal tunnel syndrome in our department, we developed a similar surgical technique for the decompression of the ulnar nerve at the elbow. Using sixteen cadaver upper limbs, we performed decompression of all the structures possibly responsible for ulnar nerve compression at the elbow. The structures involved were Struthers’ arcade, the cubital tunnel retinaculum, Osborne's fascia and Amadio-Beckenbaugh's arcade. The procedure was followed by anatomical dissection to confirm complete sectioning of the compressive structures, absence of iatrogenic vascular or nervous injuries and absence of nerve dislocation or instability. There were no remaining compressive structures after the release procedure. There was no iatrogenic damage to the nerves and no nerve dislocation was observed during elbow flexion or extension. In 3.4% cases, a thin superficial layer of one or more of the identified structures remained but these did not appear to compress the nerve based on US imaging. Using ultrasonographic visualization of the nerve and compressive structures is easy. Each procedure can be tailored according to the nerve compression sites. Our cadaveric study shows the feasibility of an US-guided percutaneous surgical release for ulnar nerve entrapment.

Lumbar artery branch injury secondary to ureteroscopic manipulation.

Iatrogenic vascular injury in ureteroscopy is relatively uncommon and typically presents as a subcapsular hematoma. We report the case of an injury to a branch of the lumbar artery secondary to ureteral trauma during ureteroscopy. In the immediate postoperative period, the patient became hypotensive and tachycardic, prompting a workup that revealed an active hemorrhage. The patient then underwent subsequent angiogram and successful coil embolization.

Incidence and Clinical Significance of Vascular Encroachment Resulting From Freehand Placement of Pedicle Screws in the Thoracic and Lumbar Spine

Retrospective case series. Evaluate the incidence and clinical significance of vascular encroachment resulting from freehand placement of pedicle screws in the thoracic and lumbosacral spine. 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. 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. 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. 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. 4.