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

Endovascular repair for thoracic aortic pseudoaneurysm induced by pedicle screw implantation: a case report with 8 years follow-up

BACKGROUND

Pedicle screw instrument surgeries can result in the development of aortic pseudoaneurysm, which is a rare yet potentially severe complication; therefore, the purpose of this work is to describe the case of pseudoaneurysm of the thoracic aorta caused by the severe migration of a pedicle screw after surgery.

CASE PRESENTATION

We herein report a patient who underwent endovascular repair for the pseudoaneurysm of the descending thoracic aorta following thoracic vertebral fixation surgery. A 28-80 mm covered stent was initially inserted through the right femoral artery, and intraoperative aortography revealed a minor extravasation of contrast material. Subsequently, an additional 28-140 mm covered stent was implanted. The patient recovered well during the 8-year follow-up period.

CONCLUSIONS

Vascular complications resulting from spinal surgery are severe and rare, necessitating early diagnosis and intervention.

Tips and pitfalls to improve accuracy and reduce radiation exposure in intraoperative CT navigation for pediatric scoliosis: a systematic review

BACKGROUND CONTEXT

An increasing number of medical centers are adopting an intraoperative computed tomography (iCT) navigation system (iCT-Navi) to provide three-dimensional navigation for pediatric scoliosis surgery. While iCT-Navi has been reported to provide higher pedicle screw (PS) insertion accuracy, it may also result in higher radiation exposure to the patient. What innovations and studies have been introduced to reduce radiation exposure and further improve PS insertion?

PURPOSE

Evaluate the level of evidence and quality of papers while categorizing the tips and pitfalls regarding pediatric scoliosis surgery using iCT-Navi. Compare iCT-Navi with other methods, including preoperative CT navigation.

STUDY DESIGN

Systematic review.

PATIENT SAMPLE

Articles on pediatric scoliosis surgery with iCT-Navi published through to June 2022.

OUTCOME MEASURES

PS perforation rate and patient intraoperative radiation dose.

METHODS

Following PRISMA guidelines, the Cochrane Library, Google Scholar, and PubMed databases were searched for articles satisfying the criteria of iCT-Navi use and pediatric scoliosis surgery. The level of evidence and quality of the articles meeting the criteria were evaluated according to the guidelines of the North American Spine Society and American Academy of Orthopedic Surgeons, respectively. The articles were also categorized by theme and summarized in terms of PS insertion accuracy and intraoperative radiation dose. The origins and characteristics of five major classification methods of PS perforation grade were summarized as well.

RESULTS

The literature search identified 811 studies, of which 20 papers were included in this review. Overall, 513 pediatric scoliosis patients (381 idiopathic, 44 neuromuscular, 39 neurofibromatosis type 1, 28 congenital, 14 syndromic, seven other) were evaluated for PS perforations among 6,209 iCT-Navi insertions. We found that 232 (3.7%) screws were judged as major perforations (G2 or G3), 55 (0.9%) screws were judged as dangerous deviations (G3), and seven (0.1%) screws were removed. There were no reports of neurovascular injury caused by PSs. The risk factors for PS perforation included more than six vertebrae distance from the reference frame, more than nine consecutive insertions, upper thoracic level, thinner pedicle, upper instrumented vertebra proximity, short stature, and female. The accuracy of PS insertion did not remarkably decrease when the radiation dose was reduced to 1/5 or 1/10 by altering the iCT-Navi protocol.

CONCLUSIONS

iCT-Navi has the potential to reduce PS perforation rates compared with other methods. The use of low-dose radiation protocols may not significantly affect PS perforation rates. Although several risk factors for PS perforation and measures to reduce radiation dose have been reported, the current evidence is limited by a lack of consistency in classifying PS perforation and evaluating patient radiation dose among studies. The standardization of several outcome definitions is recommended in this rapidly developing field.

Tactics for the treatment of potential and true thoracic aorta injuries by pedicle screws in the absence of acute bleeding: analysis of a small clinical series and literature data

Objective. To analyse the results of treatment of patients in whom, after fixation of the thoracic spine, contact of screws with the aorta with its wall injury was revealed.Material and Methods. Three own observations and literature data were analysed.Results. Three patients with potential (1 case) and true (2 cases) injury to the thoracic aorta by a transpedicular screw underwent simultaneous surgical intervention including thoracic endovascular aortic repair (TEVAR) followed by remounting (2 cases) or removal of the transpedicular fixation system. An analysis of publications on this topic is presented.Conclusion. Intramural hematoma caused by screw malposition is an indication for aortic repair due to the risk of its dissection or rupture.It is advisable to give preference to endovascular methods of treating vascular injuries under conditions of local anesthesia as the first stage, and then to perform the revision of transpedicular fixation system under anesthesia.

Reduction in Radiation Exposure in Minimally Invasive Pedicle Screw Placement Using a Tubular Retractor: A Pilot Study

BACKGROUND AND OBJECTIVES

Percutaneous pedicle screw (PPS) placement is a minimally invasive spinal procedure that has been rapidly adopted over the last decade. However, PPS placement has elicited fear of increased radiation exposure from some surgeons, medical staff, and patients. This is because PPS placement is performed using a K-wire, and the operator must perform K-wire insertion into the pedicle under fluoroscopy. In order to prevent erroneous insertion, there are many occasions when direct insertion is required during radiation exposure, and the amount of radiation exposure to hands and fingers in particular increases. Although these problems are being addressed by navigation systems, these systems are still expensive and not widely available. Attempts have been made to address this situation using instrumentation commonly used in spinal surgery. First, it was considered to visualize anatomical bone markers using a tubular retractor and a microscope. In addition, the use of a self-drilling pin was adopted to locate the pedicle in a narrower field of view. Based on these considerations, a minimally invasive and highly accurate pedicle screw placement technique was developed while avoiding direct radiation exposure. This study evaluated radiation exposure and accuracy of pedicle screw placement using this new procedure in one-level, minimally invasive, transforaminal lumbar interbody fusion (MIS-TLIF).

MATERIALS AND METHODS

Data were collected retrospectively to review pedicle screw placement in single-level MIS TLIFs using a tubular retractor under a microscope. The total fluoroscopy time, radiation dose, and screw placement accuracy were reviewed. Extension of operating time was also evaluated.

RESULTS

Twenty-four patients underwent single-level MIS TLIFs, with placement of 96 pedicle screws. There were 15 females and 9 males, with an average age of 64.8 years and a mean body mass index of 25.5 kg/m². The mean operating time was 201.8 min. The mean fluoroscopic time was 26.8 s. The mean radiation dose of the area dose product was 0.0706 mGy∗m². The mean radiation dose of air kerma was 6.0 mGy. The mean radiation dose of the entrance skin dose was 11.31 mGy. Postoperative computed tomography scans demonstrated 93 pedicle screws confined to the pedicle (97%) and three pedicle screw breaches (3.2%; two lateral, one medial). A patient with screw deviation of the medial pedicle wall developed right-foot numbness necessitating reoperation. There were no complications after reoperation. The average added time with this combined procedure was 39 min (range 16-69 min) per patient.

CONCLUSIONS

This novel pedicle screw insertion technique compares favorably with other reports in terms of radiation exposure reduction and accuracy and is also useful from the viewpoint of avoiding direct radiation exposure to hands and fingers. It is economical because it uses existing spinal surgical instrumentation.

Design, Fabrication, and Accuracy of a Novel Noncovering Lock-Mechanism Bilateral Patient-Specific Drill Guide Template for Nondeformed and Deformed Thoracic Spines

Background: Pedicle screw (PS) placement has been widely used in fusion surgeries on the thoracic spine. Achieving cost-effective yet accurate placements through nonradiation techniques remains challenging. Questions/Purposes: Novel noncovering lock-mechanism bilateral vertebra-specific drill guides for PS placement were designed/fabricated, and their accuracy for both nondeformed and deformed thoracic spines was tested. Methods: One nondeformed and 1 severe scoliosis human thoracic spine underwent computed tomographic (CT) scanning, and 2 identical proportions of each were 3-dimensional (3D) printed. Pedicle-specific optimal (no perforation) drilling trajectories were determined on the CT images based on the entry point/orientation/diameter/length of each PS. Vertebra-specific templates were designed and 3D printed, assuring minimal yet firm contacts with the vertebrae through a noncovering lock mechanism. One model of each patient was drilled using the freehand and one using the template guides (96 pedicle drillings). Postoperative CT scans from the models with the inserted PSs were obtained and superimposed on the preoperative planned models to evaluate deviations of the PSs. Results: All templates fitted their corresponding vertebra during the simulated operations. As compared with the freehand approach, PS placement deviations from their preplanned positions were significantly reduced: for the nonscoliosis model, from 2.4 to 0.9 mm for the entry point, 5.0° to 3.3° for the transverse plane angle, 7.1° to 2.2° for the sagittal plane angle, and 8.5° to 4.1° for the 3D angle, improving the success rate from 71.7% to 93.5%. Conclusions: These guides are valuable, as the accurate PS trajectory could be customized preoperatively to match the patients' unique anatomy. In vivo studies will be required to validate this approach.

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%.

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.

Complications of Thoracolumbar Adult Spinal Deformity Surgery

Adult spinal deformity (ASD) is a challenging problem for spine surgeons given the high risk of complications, both medical and surgical. Surgeons should have a high index of suspicion for medical complications, including cardiac, pulmonary, thromboembolic, genitourinary and gastrointestinal, renal, cognitive and psychiatric, and skin conditions, in the perioperative period and have a low threshold for involving specialists. Surgical complications, including neurologic injuries, vascular injuries, proximal junctional kyphosis, durotomy, and pseudarthrosis and rod fracture, can be devastating for the patient and costly to the health-care system. Mortality rates have been reported to be between 1.0% and 3.5% following ASD surgery. With the increasing rate of ASD surgery, surgeons should properly counsel patients about these risks and have a high index of suspicion for complications in the perioperative period.

Delayed Penetration of the Thoracic Aorta by Pedicle Screws: A Case Report of Screws Left As-Is

STUDY DESIGN

A case report.

OBJECTIVE

Presentation of a patient diagnosed with perforation of the aorta by pedicle screws at levels T6 and T9 2 years after spinal fusion, who was advised no intervention. Review of other reported cases that did not undergo excision of the penetrating screws.

SUMMARY OF BACKGROUND DATA

More than 30 cases of aortic penetration by pedicle screws were described. Gradual penetration of the screws into the aorta rarely causes symptoms other than backache. However, only two cases were treated conservatively.

METHODS

A 65-year-old female patient underwent spinal decompression and T5-T10 posterior fusion following a spinal abscess. Two years and 8 months postoperatively, she underwent a computed tomography scan for suspicion of spinal hardware infection, which showed T6 and T10 screws penetrating the thoracic aorta.

RESULTS

Due to high morbidity, the patient was not offered an operation for screw excision.

CONCLUSION

This case report adds to the only two previous reports of patients who did not undergo revision of pedicle screws penetrating thoracic aorta.

LEVEL OF EVIDENCE

5.

The methods for inserting lumbar bicortical pedicle screws from the anatomical perspective of the prevertebral great vessels

BACKGROUND

At present, bicortical pedicle screws (BPSs) are not used clinically because they carry the potential risk of damaging the prevertebral great vessels (PGVs). The authors observed the anatomical relationship between the PGVs and simulated BPSs at different transverse screw angles (TSAs), exploring the insertion method of the BPS.

METHODS

Computed tomography angiography (CTA) images from 65 adults were collected. A total of 4-5 TSAs of the BPSs were simulated on the left and right sides of L1-L5 (L1-L3: 0°, 5°, 10°, 15°; L4-L5: 0°, 5°, 10°, 15°, 20°). There were three types of distances from the anterior vertebral cortex (AVC) to the PGVs (D_AVC-PGV); D_{AVC-PGV < 0.50 cm}, D_{AVC-PGV ≥ 0.50 cm}, and D_AVC-PGV↑; these distances represented close, distant, and noncontact PGV, respectively.

RESULTS

The ratio of every type of PGV was calculated, and the appropriate TSA of the BPS was recommended. In L1, the recommended left TSA of the BPS was 0°, and the ratio of the close PGV was 7.69%, while the recommended right TSA was 0°-10°, and the ratio of the close PGV was 1.54-4.62%. In L2, the recommended left TSA of the BPS was 0° and the ratio of the close PGV was 1.54%, while the recommended right TSA was 0°-15° and the ratio of the close PGV was 3.08-9.23%. In L3, the recommended left TSA was 0°-5°, and the ratio of the close PGV was 1.54-4.62%. In L4, the recommended left TSA was 0°, and the ratio of the close PGV was 4.62%. BPS use was not recommended on the right side of either L3 or L4 or on the either side of L5.

CONCLUSIONS

From the anatomical perspective of the PGVs, BPSs were not suitable for insertion into every lumbar vertebra. Furthermore, the recommended methods for inserting BPSs were different in L1-L4.

Aortic Injury by Thoracic Pedicle Screw. When Is Aortic Repair Required? Literature Review and Three New Cases

PURPOSE

Aortic injury by pedicle screw is rare but can cause serious complications. It has not been clearly determined when aortic repair is necessary in cases of screw impingement without perforation of the aortic wall. In this article, we review the treatment and clinical course of pedicle screw aortic impingement and attempt to clarify this issue.

METHODS

Cases of aortic injury during thoracic screw procedures were found using a MEDLINE search and analyzed together with 3 new cases that we present.

RESULTS

Nineteen cases collected from the literature and 3 new cases were included in the study. In 7 of the cases, aortic impingement by the pedicle screw was detected during postoperative follow-up (day 1) radiologic examinations. In the other cases, time to presentation of aortic impingement ranged between 2 weeks and 60 months after fixation. The main indications for thoracic spinal fixation were post-traumatic vertebral fracture and kyphoscoliosis/scoliosis. Repair of the aortic damage ranged from primary repair to stent and tube graft placement by the thoracic endovascular aortic repair method.

CONCLUSIONS

In cases in which the screw impinges less than 5 mm into the aortic wall, hardware revision without aortic repair may be sufficient if recognized early and there are no sign of aortic leakage in vascular imaging. However, cases with more than 5 mm of screw impingement should undergo aortic repair first, even in the absence of aortic leakage, following by screw revision.

Endovascular retrieval of a migrating pedicle screw within the inferior vena cava after instrumented spinal surgery: case report

During L3-5 instrumented spinal surgery for degenerative spondylolisthesis in a 75-year-old woman, the right L-3 pedicle screw was accidentally pushed into the retroperitoneum and then migrated to the inferior vena cava (IVC). The patient was transferred to the surgical intensive care unit, and after careful discussion with cardiology specialists, a minimally invasive endovascular technique was used to remove the migrating pedicle screw within the IVC and thus salvage this critical case. Pedicle screw instrumentation is an effective procedure, but not risk free. Every detail should be scrutinized during surgery, even instrument construction. A minimally invasive endovascular technique should be considered in this patient population.

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.

Thoracic Aortic Injury: Embolization of the Tenth Intercostal Artery and Endovascular Treatment in a Young Woman after Posterior Spinal Instrumentation

Iatrogenic aortic injuries are rare and well-recognized complications of a variety of procedures, including spinal surgery. The placement of pedicle screws is sometimes associated with devastating consequences. Aortic perforation with rapid hematoma formation and delayed aortic trauma leading to pseudoaneurysm formation have been described in the literature. A case describing a significant time interval between iatrogenic aortic injury and diagnosis in the absence of pseudoaneurysm formation is described in this paper and, according to our knowledge, is unique in the literature. The aortic injury was successfully treated, selecting the appropriate graft and, as a consequence, normal spinal cord blood flow was achieved.