Aortoiliac Vascular Injuries After Misplacement of Fixation Screws

CTA Imaging of Peripheral Arterial Injuries

Traumatic vascular injuries consist of direct or indirect damage to arteries and/or veins and account for 3% of all traumatic injuries. Typical consequences are hemorrhage and ischemia. Vascular injuries of the extremities can occur isolated or in association with major trauma and other organ injuries. They account for 1-2% of patients admitted to emergency departments and for approximately 50% of all arterial injuries. Lower extremities are more frequently injured than upper ones in the adult population. The outcome of vascular injuries is strictly correlated to the environment and the time background. Treatment can be challenging, notably in polytrauma because of the dilemma of which injury should be prioritized, and treatment delay can cause disability or even death, especially for limb vascular injury. Our purposes are to discuss the role of computed tomography angiography (CTA) in the diagnosis of vascular trauma and its optimized protocol to achieve a definitive diagnosis and to assess the radiological signs of vascular injuries and the possible pitfalls.

A photoacoustics-enhanced drilling probe for radiation-free pedicle screw implantation in spinal surgery

This article proposes a novel intra-operative navigation and sensing system that optimizes the functional accuracy of spinal pedicle screw implantation. It does so by incorporating radiation-free and multi-scale macroscopic 3D ultrasound (US) imaging and local tissue-awareness from in situ photoacoustic (PA) sensing at a clinically relevant mesoscopic scale. More specifically, 3D US imaging is employed for online status updates of spinal segment posture to determine the appropriate entry point and coarse drilling path once non-negligible or relative patient motion occurs between inter-vertebral segments in the intra-operative phase. Furthermore, a sophisticated sensor-enhanced drilling probe has been developed to facilitate fine-grained local navigation that integrates a PA endoscopic imaging component for in situ tissue sensing. The PA signals from a sideways direction to differentiate cancellous bone from harder cortical bone, or to indicate weakened osteoporotic bone within the vertebrae. In so doing it prevents cortical breaches, strengthens implant stability, and mitigates iatrogenic injuries of the neighboring artery and nerves. To optimize this PA-enhanced endoscopic probe design, the light absorption spectrum of cortical bone and cancellous bone are measured in vitro, and the associated PA signals are characterized. Ultimately, a pilot study is performed on an ex vivo bovine spine to validate our developed multi-scale navigation and sensing system. The experimental results demonstrate the clinical feasibility, and hence the great potential, for functionally accurate screw implantation in complex spinal stabilization interventions.

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.

Does Three-dimensional Printing Plus Pedicle Guider Technology in Severe Congenital Scoliosis Facilitate Accurate and Efficient Pedicle Screw Placement?

BACKGROUND

Three-dimensional (3-D) printing offers the opportunity to create patient-specific guides for pedicle screw placement based on CT-generated models. This technology might allow for more-accurate placement of pedicle screws in patients with severe congenital scoliosis who have rotated vertebrae and small pedicles, but to our knowledge, this premise has not been tested.

QUESTIONS/PURPOSES

(1) Is the use of 3-D printing and pedicle guider technology as or more accurate than the use of the freehand technique for pedicle-screw placement in patients with severe congenital scoliosis? (2) Does surgical time differ with the use of these guiders? (3) Are complications less common in patients treated with this new approach to pedicle-screw placement?

METHODS

A prospective controlled study was conducted of patients with severe congenital scoliosis (major curve ≥ 90°) from June 2016 to June 2018. During this period, we treated 93 patients with congenital scoliosis; 32 had severe scoliosis with a major curve ≥ 90°. The patients were divided into a pedicle guider group (n = 15) and a control group (n = 17) based on their willingness to use pedicle guider technology, which was considered a research technology. With the numbers available, there were no between-group differences in terms of age, sex, BMI, or parameters related to curve severity or flexibility, and all patients in both groups had severe curves. Preoperative and postoperative low-dose CT scans were performed in the two groups. In the pedicle guider group, custom software was used to design the pedicle guider, and a 3-D printer was used to print a physical spinal model and pedicle guiders. The pedicle guiders were tested on the surface of the physical spinal model before surgery to ensure proper fit, and then used to assist pedicle screw placement during surgery. A total of 244 screws were implanted with the help of 127 pedicle guiders (254 guiding tunnels) during surgery in the PG group. Five predesigned pedicle guiders were abandoned due to an unstable match, and the success rate of assisted screw placement using a pedicle guider was 96% (244 of 254). The freehand technique was used in the control group, which relied on anatomic localization to place pedicle screws. The accuracy of pedicle screw placement was evaluated with CT scans, which revealed whether screws had broken through the pedicle cortex. We compared the groups in terms of accuracy (defined as unanticipated breaches less than 2 mm), surgical time, time to place pedicle screws, and screw-related complications.

RESULTS

A higher proportion of the screws placed using pedicle guider technology were positioned accurately than were in the control group (93% [227 of 244] versus 78% [228 of 291]; odds ratio, 3.69 [95% CI, 2.09-6.50]; p<0.001). With pedicle guider use, operative time (296 ± 56 versus 360 ± 74; 95% CI, -111 to -17; p = 0.010), time to place all screws (92 ± 17 versus 118 ± 21; 95% CI, -39 to -12; p = 0.001), and mean time to place one screw (6 ± 1 versus 7 ± 1; 95% CI, -2 to 0; p = 0.011) decreased. One patient in the pedicle guider group and four in the control group experienced screw-related complications; the sample sizes and small number of complications precluded statistical comparisons.

CONCLUSIONS

In this small, preliminary study, we showed that the accuracy of the surgical technique using spinal 3-D printing combined with pedicle guider technology in patients with severe congenital scoliosis was higher than the accuracy of the freehand technique. In addition, the technique using pedicle guider technology appeared to shorten operative time. If these findings are confirmed in a larger study, pedicle guider technology may be helpful for situations in which intraoperative CT or O-arm navigation is not available.

LEVEL OF EVIDENCE

Level II, therapeutic study.

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.

Fluoroscopy-guided pedicle screw accuracy with a mini-open approach: a tomographic evaluation of 470 screws in 125 patients

BACKGROUND

Transpedicular screws are currently placed with open free hand and minimally invasive techniques assisted with either fluoroscopy or navigation. Screw placement accuracy had been investigated with several methods reaching accuracy rates from 71.9% to 98.8%. The objective of this study was to assess the accuracy and safety for 2-D fluoroscopy-guided screw placement assisted with electrophysiological monitoring and the inter-observer agreement for the breach classification.

METHODS

A retrospective review was performed on 125 consecutive patients who underwent minimally invasive transforaminal lumbar interbody fusion and transpedicular screws placement between the levels of T-12 and S-1. Screw accuracy was evaluated using a postoperative computed tomography by three independent observers. Pedicle breach was documented when there was a violation in any direction of the pedicle. Inter-observer agreement was assessed with the Kappa coefficient.

RESULTS

A total of 470 transpedicular screws were evaluated between the levels of T-12 and S-1. In 57 patients the instrumentation was bilateral and in 68 unilateral. A substantial degree of agreement was found between the observers AB (κ=0.769) and A-C (κ=0.784) and almost perfect agreement between observers B-C (κ=0.928). There were a total of 427.33 (90.92%) screws without breach, 39.33 (8.37%) minor breach pedicles and 3.33 (0.71%) major breach pedicles. The pedicle breach rate was 9.08% Trajectory pedicle breach percentages were as follows: minor medial pedicle breach 4.68%, minor lateral pedicle breach 3.47%, minor inferior pedicle breach 0.22%, and major medial breach 0.70%. No intraoperative instrumentation-related or postoperative clinical complications were encountered and no surgical revision was needed.

CONCLUSIONS

Our study demonstrated a high accuracy (90.2%) for 2-D fluoroscopy-guided pedicle screw using electromonitoring. Only 0.71% of the 470 screws had a major breach. Knowing the radiological spine pedicle anatomy and the correct interpretation of EMG are the key factors for this technique.

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.

Position of the aorta relative to the spine in patients with thoracolumbar/lumbar kyphosis secondary to ankylosing spondylitis

STUDY DESIGN

A computed tomographic study.

OBJECTIVE

To explore the anatomic relationship between the aorta and the spine in patients with thoracolumbar/lumbar kyphosis secondary to ankylosing spondylitis (AS).

SUMMARY OF BACKGROUND DATA

The lumbar spinal osteotomy has been widely adopted for the correction of thoracolumbar/lumbar kyphosis caused by AS. During this procedure, the aorta may be stretched at the osteotomized level and in proximity to the tip of the pedicle screw, both of which imply a potential risk of the aortic injury. To date, no reports have been specifically published for describing the position of the aorta relative to the spine in patients with AS with fixed thoracolumbar/lumbar kyphosis.

METHODS

Thirty-three patients with AS with thoracolumbar/lumbar kyphosis and 38 age- and sex-matched patients with a normal spine were included in this study. For each subject, the left pedicle-aorta angle and distance were measured from T9 to L3 on the computed tomographic scans. Radiographs were analyzed to measure the global kyphosis, lumbar lordosis, and to record the apex of the kyphotic curve.

RESULTS

At T9-L3 levels, patients with AS with thoracolumbar/lumbar kyphosis exhibited significantly smaller left pedicle-aorta angles (from 10.23° to -11.56°) and larger distances (from 39.0 to 55.5 mm) than those with a normal spine. With increased global kyphosis, the aorta shifted more laterally to the right at periapical levels (L1 and L2, P < 0.05). Notably, the aorta was located at the middle front of the vertebrae at T12-L1 levels and far away from the vertebrae at L2 and L3 levels.

CONCLUSION

In patients with AS with thoracolumbar/lumbar kyphosis, the aorta is positioned more anteromedially relative to the vertebral body than that in the normal subjects. The aorta is far away from the vertebral body at L2 and L3 levels, thus it could be much safer to perform osteotomy below L1.

LEVEL OF EVIDENCE

4.

Delayed presentation of a thoracic aortic injury with a vertebral pedicle screw

Iatrogenic aortic injuries by pedicle screws are rare but serious complications of spinal fixation surgery. We report the case of a 55-year-old man who underwent surgical correction of traumatic thoracic vertebral fractures at another institution. At 6-month follow-up, computed tomography revealed a nonhealing of the fractures, and a T4 misplaced pedicle screw penetrating the descending thoracic aorta. The patient underwent open aortic repair associated with the anterior vertebral column reconstruction and posterior arthrodesis revision by a vascular and orthopedic surgery team simultaneously.

Treatment of iatrogenic IVC occlusion with implantation of a stent of a new shape dedicated to aortic aneurysms

Background:

Successful treatment of chronic occlusion of inferior vena cava (IVC) and iliocaval confluence with angioplasty and stent implantation is very rare.

Case Report:

We present a case of a 59-year-old patient with iatrogenic occlusion of IVC following L3/L4 discectomy. The wall of the ventral IVC was ruptured during the operation.

Results:

The torn wall was treated by patch angioplasty, resulting in a permanent IVC occlusion, as confirmed by angiography. Iatrogenic permanent occlusion of IVC was successfully treated with recanalization and implantation of a non-covered aortic stent.

Clinically relevant complications related to pedicle screw placement in thoracolumbar surgery and their management: a literature review of 35,630 pedicle screws

OBJECT

The technique of pedicle screw insertion is a mainstay of spinal instrumentation. Some of its potential complications are clinically relevant and may require reoperation or further postoperative care.

METHODS

A literature search was performed using MEDLINE (between 1999 and June 2011) for studies on pedicle screw placement in thoracolumbar surgery. The authors included randomized controlled trials, case-control studies, and case series (≥ 20 patients) from the English-, German-, and French-language literature. The authors assessed study type, the number of patients, the anatomical area, the number of pedicle screws, duration of follow-up, type of pedicle screw placement, incidence of complications, and type of complication. The management of specific complications is discussed.

RESULTS

Thirty-nine articles with 46 patient groups were reviewed with a total of 35,630 pedicle screws. One study was a randomized controlled trial, 8 were case-control studies, and the remaining articles were case series. Dural lesions and irritation of nerve roots were reported in a mean of 0.18% and 0.19% per pedicle screws, respectively. Thirty-two patients in 10 studies (of 5654 patients from all 39 studies) required further revision surgeries for misplaced pedicle screws causing neurological problems. None of the analyzed studies reported vascular complications, and only 2 studies reported visceral complications of clinical significance.

CONCLUSIONS

Pedicle screw placement in the thoracolumbar region is a safe procedure with an overall high accuracy and a very low rate of clinically relevant complications.

The position of the aorta changes with altered body position in single right thoracic adolescent idiopathic scoliosis: a magnetic resonance imaging study

STUDY DESIGN

A prospective clinical magnetic resonance imaging study.

OBJECTIVE

To explore the differences in the position of the aorta relative to the spine in patients with single right thoracic adolescent idiopathic scoliosis (RT-AIS) in 2 different body positions (supine and prone).

SUMMARY OF BACKGROUND DATA

Pedicle screws are used widely in scoliosis surgery. With an increase in the incidence of vascular complications that result from misplaced pedicle screws, studies regarding the spatial relationship of the aorta and the vertebral body have also gradually increased and show that the aorta is positioned more posteriorly in patients with RT-AIS than in normal subjects. In these imaging studies, the patients received computed tomographic or magnetic resonance (MR) scans in the supine position. Recent studies of subjects without a spinal deformity found that the aorta moves from a posterolateral to an anteromedial position when the subject changes from a supine position to a prone position. However, no studies investigated aorta shifting with changing body position in patients with AIS.

METHODS

Twenty-six patients with single RT-AIS were recruited into this study. Each patient received an axial MR scan from T5 through L3 in both the supine and prone positions. In the Cartesian coordinate system, the left pedicle-aorta (LtP-Ao) angle, LtP-Ao distance, and vertebral rotation angle were measured from T5 through L3 in the axial plane MR images. We also simulated misplacement of the pedicle screw with commonly used length and 20° direction error, and the potential risk of aorta impingement was defined as the virtual pedicle screw crossing the aorta. The paired sample t test was used to compare these parameters between the 2 body positions.

RESULTS

The mean LtP-Ao angle and mean LtP-Ao distance differed between the body positions at each level. At the T5-T10 levels, the patients in the prone position exhibited significantly smaller LtP-Ao angles (26.2° vs. 38.8°; P, 0.01) and distances (27.0 vs. 30.7 mm; P, 0.01) than those in the supine position. The vertebral rotation angle was larger in the prone position than in the supine position at periapical levels, although this difference did not reach statistical significance (P . 0.05). The percentage of potential risk of aorta impingement was significantly higher in the prone position than in the supine position at the T5-T10 levels (19.7% vs. 6.6%, respectively; P, 0.05). CONCLUSION.: The aorta shifts more anteromedially and more closely to the spine at the T5-T10 levels when patients with RT-AIS change from the supine to the prone position. Thus, in the prone position, the aorta is potentially at a higher risk for injury from anterior and lateral cortex penetration by the left pedicle screws. The spinal surgeon should be aware of these altered conditions to avoid injury to the aorta during pedicle screw insertion in patients with RT-AIS who are in the prone position.

Endovascular treatment in emergency setting of acute arterial injuries after orthopedic surgery

PURPOSE

To assess the feasibility and effectiveness of emergency endovascular treatment of acute arterial injuries after orthopedic surgery.

MATERIALS AND METHODS

Fifteen patients (mean age 68.3 years) with acute arterial injuries after orthopedic surgery were observed, in particular, 5 patients with pseudoaneurysm, 9 patients with active bleeding, and 1 patient with arterial dissection. Transarterial embolization (TAE) and positioning of covered and noncovered stents were the treatments performed. Follow-up after stent implantation (mean 36 months) was performed with color Doppler US (CDU) at 1, 3, 6, and 12 months and yearly thereafter. Plain X-ray was performed to evidence dislodgment or fracture of the graft. A minimum of 12 months' follow-up is available after TAE.

RESULTS

Immediate technical success was obtained in all cases. No major complications occurred. Overall clinical success rate was 100%. During mean follow-up, stent-graft occlusions did not occurred. No recurrence and/or consequence of TAE was registered during a minimum follow-up of 12 months.

CONCLUSIONS

Percutaneous treatment is a feasible and safe tool for treating arterial injuries because it can provide fast and definitive resolution of the damage. This low-invasiveness approach can be proposed as first-line treatment in patients with acute injuries after orthopedic surgery.

Embolisation for vascular injuries complicating elective orthopaedic surgery

OBJECTIVES

The study aims to present the indications and emphasise the role of embolisation for vascular injuries in orthopaedic surgery.

METHODS

Thirty-one patients with vascular injuries complicating elective orthopaedic surgery had embolisation from 2003 to 2010. N-2-butyl cyano-acrylate (NBCA) was used as embolic agent in 28 patients, gelatin sponge in three and coil embolisation in addition to NBCA or gelatin sponge in two patients. The mean follow-up period was 37 months (range, 4-96 months).

RESULTS

The most common orthopaedic operations associated with vascular injuries amenable to embolisation were hip-joint procedures; and the most common injuries were arterial tears of branch vessels or non-critical axial vessels, most commonly of the superior glutaeal artery. In all cases, angiography showed the bleeding point, and a single embolisation session effectively stopped bleeding. Embolisation-related complications were not observed.

CONCLUSIONS

Embolisation should be considered the treatment of choice for vascular injuries of branch vessels or non-critical axial vessels following elective orthopaedic surgery because of the advantages of minimally invasive therapy and the lack of complications.