Patient knowledge regarding radiation exposure from spinal imaging

Advances in Imaging (Intraop Cone-Beam Computed Tomography, Synthetic Computed Tomography, Bone Scan, Low-Dose Protocols)

Spine surgery has seen a rapid advance in the refinement and development of 3-dimensional and nuclear imaging modalities in recent years. Cone-beam CT has proven to be a valuable tool for improving the accuracy of pedicle screw placement. The use of synthetic CT and low-dose CT have also emerged as modalities which allow for little to no radiation while streamlining imaging workflows. Bone scans also serve to provide functional information about bone metabolism in both the preoperative and postoperative monitoring phases.

Patient's knowledge regarding radiation exposure from various imaging modalities: a pilot study

To determine patients' knowledge about ionising radiation used in diagnostic imaging and whether they were adequately informed about the procedure they were referred to. A cross-sectional study was conducted at the University Hospital Merkur, Zagreb, Croatia during 2019-20. A questionnaire with 14 questions was given to patients in waiting rooms for imaging examinations. Statistical analysis was conducted using the standard software package. Chi-square with Yates correction was used to determine differences in patients' answers between those who received the explanation about the procedure and those who did not. The differences depending on the educational level were also evaluated. The survey was completed by 374 participants (200 women, 174 men) with a mean age of 55.45 ± 15.92 y. Of all patients, 8.63% had no formal education or only finished elementary school, 52.83% had finished high school and 38.55% had a college or a higher degree. The referring physicians informed 63.66% of participants about the radiological exam they were being referred to, and 226 thought that the given explanation was sufficient. Most patients knew that some radiological procedures use ionising radiation. Only 47.37% of respondents correctly identified MRI as a non-ionising method, whereas 37.40% of participants recognised chest X-ray as the modality with the lowest radiation dose. Higher-educated patients had better knowledge of radiological procedures and the potential risks. The study demonstrated suboptimal patients' knowledge about ionising radiation, and additional efforts in their education are needed.

The Use of Intraoperative CT Hounsfield Unit Values for the Assessment of Bone Quality in Patients Undergoing Lumbar Interbody Fusion

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

To evaluate the accuracy of intraoperatively measured computed tomography (CT) Hounsfield unit (HU) values by comparison with preoperative CT HU values and to compare the radiation exposure between preoperative and intraoperative CT scans.

METHODS

HU values of lumbar vertebrae were measured and compared between preoperative and intraoperative CT scans in patients undergoing lumbar interbody fusion. In patient group one, Canon CT scanners were used preoperatively and the AIRO CT scanner was used intraoperatively. In patient group two, Canon CT scanners were used preoperatively and the O-arm Cone Beam CT (CBCT) scanner was used intraoperatively. In a subgroup analysis of patient group one, radiation by means of CT Dose Index (CTDI) was compared between Canon and AIRO CT scanners.

RESULTS

In the first patient group, a total of 250 vertebrae were analysed in 74 patients showing a strong Pearson correlation of >.94 between pre- and intraoperative HU values. Bland-Altman analysis indicated consistency and equivalence with a bias of 3.9 and 95% limits of agreement from -27.17 to 34.97 when comparing all pre- and intraoperative HU values of L1-5. In the second patient group, a total of 27 vertebrae were analysed in 10 patients showing weak Pearson correlation and Bland-Altman analysis indicated no equivalence. CTDI did not differ between Canon and AIRO CT scanners.

CONCLUSION

Correct and reliable CT HU measurement as mandatory key factor for the intraoperative assessment of bone quality and robotic-assisted surgery is feasible with intraoperative AIRO CT imaging without increase of radiation exposure.

Knowledge of radiation exposure associated with common trauma imaging modalities among orthopaedic surgeons, emergency medicine physicians, and general surgeons in the United States

BACKGROUND

Few contemporary studies have assessed physicians' knowledge of radiation exposure associated with common imaging studies, especially in trauma care. The purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal (MSK) imaging studies routinely utilized in the trauma setting.

METHODS

An electronic survey was distributed to United States orthopaedic surgery, general surgery, and emergency medicine (EM) residency programs. Participants were asked to estimate the radiation dose for common imaging modalities of the pelvis, lumbar spine, and lower extremity, in terms of chest X-ray (CXR) equivalents. Physician estimates were compared to the true effective radiation doses. Additionally, participants were asked to report the frequency of discussing radiation risk with patients.

RESULTS

A total of 218 physicians completed the survey; 102 (46.8%) were EM physicians, 88 (40.4%) were orthopaedic surgeons, and 28 (12.8%) were general surgeons. Physicians underestimated the effective radiation doses of nearly all imaging modalities, most notably for pelvic computed tomaography (CT) (median 50 CXR estimation vs. 162 CXR actual) and lumbar CT (median 50 CXR estimation vs. 638 CXR actual). There was no difference between physician specialties regarding estimation accuracy (P=0.133). Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure (P=0.007).

CONCLUSION

The knowledge among orthopaedic and general surgeons and EM physicians regarding the radiation exposure associated with common MSK trauma imaging is lacking. Further investigation with larger scale studies is warranted, and additional education in this area may improve care.

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.

Emerging Issues Questioning the Current Treatment Strategies for Lumbar Disc Herniation

Lumbar disc herniation is among the common phenotypes of degenerative lumbar spine diseases, significantly affecting patients' quality of life. The practice pattern is diverse. Choosing conservative measures or surgical treatments is still controversial in some areas. For those who have failed conservative treatment, surgery with or without instrumentation is recommended, causing significant expenditures and frustrating complications, that should not be ignored. In the article, we performed a literature review and summarized the evidence by subheadings to unravel the cons of surgical intervention for lumbar disc herniation. There are tetrad critical issues about surgical treatment of lumbar disc herniation, i.e., favorable natural history, insufficient evidence in a recommendation of fusion surgery for patients, metallosis, and implant removal. Firstly, accumulating evidence reveals immune privilege and auto-immunity hallmarks of human lumbar discs within the closed niche. Progenitor cells within human discs further expand the capacity with the endogenous repair. Clinical watchful follow-up studies with repeated diagnostic imaging reveal spontaneous resolution for lumbar disc herniation, even calcified tissues. Secondly, emerging evidence indicates long-term complications of lumbar fusion, such as adjacent segment disease, pseudarthrosis, implant failure, and sagittal spinal imbalance, which get increasing attention. Thirdly, systemic and local reactions (metallosis) for metal instrumentation have been noted with long-term health concerns and toxicity. Fourthly, the indications and timing for spinal implant removal have not reached a consensus. Other challenging issues include postoperative lumbar stiffness. The review provided evidence from a negative perspective for surgeons and patients who attempt to choose surgical treatment. Collectively, the emerging underlying evidence questions the benefits of traditional surgery for patients with lumbar disc herniation. Therefore, the long-term effects of surgery should be closely observed. Surgical decisions should be made prudently for each patient.

Effect of a discordant opinion offered by a second opinion physician on the patient's decision for management of spinal disc disease

BACKGROUND

Factors that influence a patient's decision for spinal surgery and selection of the spine surgeon have not been studied in the context of a Second Opinion (SO). Providing insight into these factors will guide surgeons in their discussion of treatment options with patients.

OBJECTIVE

This study aims to assess the impact of a discordant SO on the final decision of patients as compared to their initial preference regarding spinal disc disease treatment for chronic neck and low back pain.

PATIENT INVOLVEMENT

Patients in this study engage in clinical vignettes designed to induce decisional conflict.

METHODS

A cross-sectional study using clinical vignette-based questionnaires was presented to patients at the Family Medicine, Orthopedic, and Neurosurgery clinics at a university-based tertiary academic medical center.

RESULTS

A total of 246 patients participated in the study (response rate, 66.8%). Irrespective of the initial offered treatment, most patients wanted to consult a SO (64.2%). Most patients preferred conservative treatment to surgery after getting the initial recommendation (78.5%) and after getting a discordant SO (56.5%). There was an association between the agreement of the patient with the initial recommendation and the effect of the SO on the final decision of patients (p < 0.001). Patients who disagreed with the initially offered treatment were more likely to abide by their initial decision after the SO (80.8%) as compared to those who were in agreement (17.7%), while those who agreed with the initially offered treatment were more likely to change their decision (39.5%) or to take a third opinion (42.9%).

DISCUSSION

A discordant SO may validate patients' wishes when they disagree with the initially offered treatment and may lead to confusion when they agree with the initial physicians' recommendations.

PRACTICAL VALUE

As patients tend to abide by their initial preference, physicians should explicitly consider patients' wishes when discussing options for management of spinal disc disease.

Low Radiation X-rays: Benefiting People Globally by Reducing Cancer Risks

Modern medical imaging facilitates the diagnosis and treatment of human diseases. However, few people are aware of the cons of radiation exposure from medical imaging. Emerging evidence reveals that cumulative doses of radiation exposure will increase the morbidity and mortality of pertaining cancer. As a special young population, patients with adolescent idiopathic scoliosis (AIS) suffer more radiation harms from repeated diagnostic imaging, most of which can be avoided in clinical practice. Accumulating evidence highlights reduced cancer risks of radiation exposure for AIS patients with low/zero radiation imaging modalities proposed, amongst which easy conversion from anterior-posterior (AP) to posterior-anterior (PA) projection for whole-spine radiographs should be stressed. It can greatly reduce radiation doses without compromising the quality of diagnostic imaging. Tight collimation combined with PA projection can further reduce radiation harms, and need to be spread to benefit people globally.

Magnetic resonance imaging-based synthetic computed tomography of the lumbar spine for surgical planning: a clinical proof-of-concept

OBJECTIVE

Computed tomography scanning of the lumbar spine incurs a radiation dose ranging from 3.5 mSv to 19.5 mSv as well as relevant costs and is commonly necessary for spinal neuronavigation. Mitigation of the need for treatment-planning CT scans in the presence of MRI facilitated by MRI-based synthetic CT (sCT) would revolutionize navigated lumbar spine surgery. The authors aim to demonstrate, as a proof of concept, the capability of deep learning-based generation of sCT scans from MRI of the lumbar spine in 3 cases and to evaluate the potential of sCT for surgical planning.

METHODS

Synthetic CT reconstructions were made using a prototype version of the "BoneMRI" software. This deep learning-based image synthesis method relies on a convolutional neural network trained on paired MRI-CT data. A specific but generally available 4-minute 3D radiofrequency-spoiled T1-weighted multiple gradient echo MRI sequence was supplemented to a 1.5T lumbar spine MRI acquisition protocol.

RESULTS

In the 3 presented cases, the prototype sCT method allowed voxel-wise radiodensity estimation from MRI, resulting in qualitatively adequate CT images of the lumbar spine based on visual inspection. Normal as well as pathological structures were reliably visualized. In the first case, in which a spiral CT scan was available as a control, a volume CT dose index (CTDIvol) of 12.9 mGy could thus have been avoided. Pedicle screw trajectories and screw thickness were estimable based on sCT findings.

CONCLUSIONS

The evaluated prototype BoneMRI method enables generation of sCT scans from MRI images with only minor changes in the acquisition protocol, with a potential to reduce workflow complexity, radiation exposure, and costs. The quality of the generated CT scans was adequate based on visual inspection and could potentially be used for surgical planning, intraoperative neuronavigation, or for diagnostic purposes in an adjunctive manner.

Patients' and Physicians' Knowledge of Radiation Exposure Related to Spine Surgery

STUDY DESIGN

Cross-sectional survey.

OBJECTIVE

Examine patients' and physicians' estimates of radiation exposure related to spine surgery.

SUMMARY OF BACKGROUND DATA

Patients are commonly exposed to radiation when undergoing spine surgery. Previous studies suggest that patients and physicians have limited knowledge about radiation exposure in the outpatient setting. This has not been assessed for intraoperative imaging.

METHODS

A questionnaire was developed to assess awareness/knowledge of radiation exposure in outpatient and intraoperative spine care settings. Patients and surgeons estimated chest radiograph (CXR) equivalent radiation from: cervical and lumbar radiographs (anterior-posterior [AP] and lateral), computed tomography (CT), magnetic resonance imaging (MRI), intraoperative fluoroscopy, and intraoperative CT (O-arm). Results were compared to literature-reported radiation doses.

RESULTS

Overall, 100 patients and 26 providers completed the survey. Only 31% of patients were informed about outpatient radiation exposure, and only 23% of those who had undergone spine surgery had been informed about intraoperative radiation exposure. For lumbar radiographs, patients and surgeons underestimated CXR-equivalent radiation exposures: AP by five-fold (P < 0.0001) and seven-fold (P < 0.0001), respectively, and lateral by three-fold (P < 0.0001) and four-fold (P = 0.0002), respectively. For cervical CT imaging, patients and surgeons underestimated radiation exposure by 18-fold (P < 0.0001) and two-fold (P = 0.0339), respectively. For lumbar CT imaging, patients and surgeons underestimated radiation exposure by 31-fold (P < 0.0001) and three-fold (P = 0.0001), respectively. For intraoperative specific cervical and lumbar imaging, patients underestimated radiation exposure for O-arm by 11-fold (P < 0.0001) and 22-fold (P = 0.0002), respectively. Surgeons underestimated radiation exposure of lumbar O-arm by three-fold (P = 0.0227).

CONCLUSION

This study evaluated patient and physician knowledge of radiation exposure related to spine procedures. Underestimation of radiation exposure in the outpatient setting was consistent with prior study findings. The significant underestimation of intraoperative cross-sectional imaging (O-arm) is notable and needs attention in the era of increased use of such technology for imaging, navigation, and robotic spine surgery.

LEVEL OF EVIDENCE

4.

Patient Knowledge Regarding Radiation Exposure From Foot and Ankle Imaging

Foot and ankle surgeons routinely prescribe diagnostic imaging that exposes patients to potentially harmful ionizing radiation. It is unclear how well patients understand the radiation to which they are exposed. In this study, 946 consecutive new patients were surveyed regarding medical imaging and radiation exposure prior to their first appointment. Respondents compared the amount of radiation associated with chest X-rays (CXRs) with various types of foot and ankle imaging. Results were compared with actual values of radiation exposure from the published literature. Of 946 patients surveyed, 841 (88.9%) participated. Most had private insurance (82.8%) and a bachelor's degree or higher (60.6%). Most believed that foot X-ray, ankle X-ray, "low dose" foot and ankle computed tomography (CT) scan (alluding to cone-beam CT), and traditional foot and ankle CT scan contain similar amounts of ionizing radiation to CXR. This contradicts the published literature that suggests that the actual exposure to patients is 0.006, 0.006, 0.127, and 0.833 CXR equivalents of radiation, respectively. Of patients who had undergone an X-ray, 55.9% thought about the issue of radiation prior to the study, whereas 46.1% of those undergoing a CT scan considered radiation prior to the exam. Similarly, 35.2% and 27.6% reported their doctor having discussed radiation with them prior to obtaining an X-ray and CT scan, respectively. Patients greatly overestimate the radiation exposure associated with plain film X-rays and cone-beam CT scans of the foot and ankle, and may benefit from increased counseling regarding the relatively low radiation exposure associated with these imaging modalities.Level of Evidence: Level III: Prospective questionnaire.

Pedicle screw placement accuracy using ultra-low radiation imaging with image enhancement versus conventional fluoroscopy in minimally invasive transforaminal lumbar interbody fusion: an internally randomized controlled trial

OBJECTIVE A previous study found that ultra-low radiation imaging (ULRI) with image enhancement significantly decreases radiation exposure by roughly 75% for both the patient and operating room personnel during minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) (p < 0.001). However, no clinical data exist on whether this imaging modality negatively impacts patient outcomes. Thus, the goal of this randomized controlled trial was to assess pedicle screw placement accuracy with ULRI with image enhancement compared with conventional, standard-dose fluoroscopy for patients undergoing single-level MIS-TLIF. METHODS An institutional review board-approved, prospective internally randomized controlled trial was performed to compare breach rates for pedicle screw placement performed using ULRI with image enhancement versus conventional fluoroscopy. For cannulation and pedicle screw placement, surgery on 1 side (left vs right) was randomly assigned to be performed under ULRI. Screws on the opposite side were placed under conventional fluoroscopy, thereby allowing each patient to serve as his/her own control. In addition to standard intraoperative images to check screw placement, each patient underwent postoperative CT. Three experienced neurosurgeons independently analyzed the images and were blinded as to which imaging modality was used to assist with each screw placement. Screw placement was analyzed for pedicle breach (lateral vs medial and Grade 0 [< 2.0 mm], Grade 1 [2.0-4.0 mm], or Grade 2 [> 4.0 mm]), appropriate screw depth (50%-75% of the vertebral body's anteroposterior dimension), and appropriate screw angle (within 10° of the pedicle angle). The effective breach rate was calculated as the percentage of screws evaluated as breached > 2.0 mm medially or postoperatively symptomatic. RESULTS Twenty-three consecutive patients underwent single-level MIS-TLIF, and their sides were randomly assigned to receive ULRI. No patient had immediate postoperative complications (e.g., neurological decline, need for hardware repositioning). On CT confirmation, 4 screws that had K-wire placement and cannulation under ULRI and screw placement under conventional fluoroscopy showed deviations. There were 2 breaches that deviated medially but both were Grade 0 (< 2.0 mm). Similarly, 2 breaches occurred that were Grade 1 (> 2.0 mm) but both deviated laterally. Therefore, the effective breach rate (breach > 2.0 mm deviated medially) was unchanged in both imaging groups (0% using either ULRI or conventional fluoroscopy; p = 1.00). CONCLUSIONS ULRI with image enhancement does not compromise accuracy during pedicle screw placement compared with conventional fluoroscopy while it significantly decreases radiation exposure to both the patient and operating room personnel.