Radiation exposure to the surgeon during minimally invasive spine procedures is directly estimated by patient dose

Radiation Exposure and Dose Estimates of Robot-Guided Versus Fluoroscopy-Guided Spinal Fusion: A Meta-Analysis of Randomized Controlled Trials

STUDY DESIGN

Systematic review and meta-analysis.

SUMMARY OF BACKGROUND DATA

Robot-guided (RG) pedicle screw placement offers several advantages over fluoroscopy-guided (FG) surgery to patients undergoing spinal fusion. Radiation exposure and detrimental risks associated with RG surgery are poorly described in the literature.

OBJECTIVES

We perform a systematic review and meta-analysis of randomized controlled trials comparing RG to FG spinal fusion to assess radiation exposure to patients and clinicians.

METHODS

MEDLINE, Embase, Web of Science, and Cochrane Central were systematically queried. Inclusion was restricted to RCTs in adults. Version 2 of the Cochrane risk-of-bias tool for RCTs (RoB 2) was used to evaluate risk of bias and quality was appraised using the GRADE assessment tool. Continuous data were pooled across trials with inverse variance weighting to mean difference (MD) and dichotomous data were pooled with Mantel-Haenszel weighting to odds ratio (OR) with corresponding 95% CI.

RESULTS

A total of 1042 patients (RG: 651; FG: 391) from 8 RCTs were included. Radiation time was reduced in the RG group by 39.6% (MD: -25.65 seconds, 95% CI: -51.07 to -0.22) with an estimated anteroposterior and lateral dose-area product in the RG group measuring 123.85±73.12 and 241.08±142.33 cGycm2, respectively. Estimated cancer risk and detrimental hereditary disorder risk were reduced by 40.2% in the RG group (3.60×10-5±2.12×10-5 and 1.31×10-6±7.72×10-7, respectively). Intraoperative bleeding volume was reduced in the RG group (MD: -61.52 mL, 95% CI: -100.16 to -22.87, P=0.002, I2=48%). However, surgical duration was significantly higher in the RG group (MD: 12.01 min, 95% CI: 1.63-22.39). Pedicle screw accuracy and length of hospital stay differences were not significant.

CONCLUSIONS

Radiation exposure to patients undergoing spinal fusion is lower in RG surgery compared with FG surgery. These findings can be supported with long-term studies that better characterize radiation dosages associated with these procedures.

LEVEL OF EVIDENCE

Level I.

Minimally Invasive Surgery for Adolescent Idiopathic Scoliosis: A Systematic Review

Background: Minimally invasive surgical (MIS) techniques have gained popularity as a safe and effective alternative to open surgery for degenerative, traumatic, and metastatic spinal pathologies. In adolescent idiopathic scoliosis, MIS techniques comprise anterior thoracoscopic surgery (ATS), posterior minimally invasive surgery (PMIS), and vertebral body tethering (VBT). In the current systematic review, the authors collected and analyzed data from the available literature on MIS techniques in AIS. Methods: The articles were shortlisted after a thorough electronic and manual database search through PubMed, EMBASE, and Google Scholar. Results: The authors included 43 studies for the review; 14 described the outcomes with ATS, 13 with PMIS, and 16 with VBT. Conclusions: While the efficacy of the ATS approach is well-established in terms of comparable coronal and sagittal correction to posterior spinal fusion, the current use of ATS for instrumented fusion has become less popular due to a steep learning curve, high pulmonary and vascular complication rates, implant failures, and increased non-union rates. PMIS is an effective alternative to the standard open posterior spinal fusion, with a steep learning curve and longer surgical time being potential disadvantages. The current evidence, albeit limited, suggests that VBT is an attractive procedure that merits consideration in terms of radiological correction and clinical outcomes, but it has a high complication and re-operation rate, while the most appropriate indications and long-term outcomes of this technique remain unclear.

Is navigation beneficial for transforaminal endoscopic lumbar foraminotomy? A preliminary comparison study with fluoroscopic guidance

PURPOSE

The primary purpose of this study was to determine radiation exposure of the surgeon during transforaminal endoscopic lumbar foraminotomy (TELF). Secondary purpose of this study was to compare clinical and radiologic outcomes between TELF under C-arm fluoroscopic guidance (C-TELF) and O-arm navigation-guided TELF (O-TELF).

METHODS

The author reviewed patients' medical records who underwent TELF at our institute from June 2015 to November 2022. A total of 40 patients were included (18 patients with C-TELF and 22 with O-TELF). Basic demographic data were collected. Preoperative/postoperative visual analog scale (VAS) and Oswestry Disability Index (ODI) were recorded at the outpatient clinic. Radiologic features were compared on X-rays at each follow-up. The degree of foraminal expansion was measured/compared through MRI. In the C-TELF group, the amount of exposure was calculated with a dosimeter.

RESULTS

Average surgeon's effective dose in the C-TELF group was 0.036 mSv. In the case of the O-TELF group, there was no radiation exposure during operation. However, the operation time in the O-TELF group was about 37 min longer than that in the C-TELF group. There were significant improvements in VAS/ODI after operation in both groups. Complications were identified in three patients.

CONCLUSION

O-TELF showed similarly favorable clinical and radiologic outcomes to C-TELF in lumbar foraminal stenosis, including complication rate. Compared to C-TELF, O-TELF has an advantage of not wearing a lead apron since the operator is not exposed to radiation. However, the operation time was longer with O-TELF due to O-arm setting time. Because there are pros and cons, the choice of surgical method depends on the surgeon's preference.

Effects of robot-assisted minimally invasive surgery on osteoporotic vertebral compression fracture: a systematic review, meta-analysis, and meta-regression of retrospective study

OBJECTIVE

To conduct a systematic review on the effect of robot-assisted minimally invasive surgery (R-MIS) on the clinical outcomes and complications of patients with osteoporotic vertebral compression fractures (OVCFs).

METHODS

The researchers searched the papers published on PubMed, The Cochrane Library, Web of Science, Embase, Scopus, Ovid MEDLINE, Wiley Online Library, China National Knowledge Infrastructure (CNKI), Chinese biomedical literature service system (SinoMed), and China Medical Association Data. The standardized mean difference (SMD) or mean difference (MD), relative risk (RR), and 95% confidence interval (CI) were calculated. Besides, the data was merged through the random-effect model or common-effect model. A meta-regression mixed-effects single-factor model was utilized to analyze the sources of heterogeneity.

RESULTS

Twelve studies were included, involving 1042 OVCFs cases. The prognosis of patients treated with R-MIS was significantly improved, such as Oswestry disability index (ODI) score (MD = -0.65, P = 0.0171), Cobb's angles (MD = -1.03, P = 0.0027), X-ray fluoroscopy frequency (SMD = -2.41, P < 0.0001), Length of hospital stay (MD = -0.33, P = 0.0002), and Cement leakage (RR = 0.37, P < 0.0001). However, no obvious improvement was found in the results of Visual analog scale (VAS) score (MD = -0.16, P = 0.1555), Volume of bone cement (MD = 0.22, P = 0.8339), and Operation time (MD = -3.20, P = 0.3411) after being treated by R-MIS. The meta-regression analysis demonstrated that R-MIS presented no significant impact on the covariates of VAS and Operation time.

CONCLUSION

R-MIS can significantly reduce the patients' ODI, Cobb's angles, X-ray fluoroscopy frequency, and Cement leakage ratio, and shorten the Length of hospital stay. Therefore, R-MIS may be an effective method to promote the patients' functional recovery, correct spinal deformity, reduce the X-ray fluoroscopy frequency, shorten the Length of hospital stay, and reduce the complications of OVCFs bone Cement leakage.

Can intraoperative radiation dose in percutaneous posterior thoracolumbar internal fixation be reduced by impedancemetry-guided pedicle sighting? A prospective randomized study

INTRODUCTION

Percutaneous spine surgery is on the rise; the main drawback is iterative irradiation of the care team in theater. The aim of the present study was to compare intraoperative radiation dose in percutaneous posterior thoracolumbar internal fixation (PPTLIF) using impedancemetry-guided pedicle sighting by the PediGuard device (SpineGuard®) versus gold-standard free-hand sighting.

MATERIAL AND METHODS

A single-center, single-surgeon continuous prospective randomized study was conducted from September 2017 to April 2018. Dose-area product (DAP, in cGy.cm²) was recorded at the end of pedicle sighting and end of surgery in the free-hand control group and the impedancemetry group. Pedicle screw position was studied on postoperative CT scan.

RESULTS

Sixteen patients were included in either group after 2 had been excluded. The groups were comparable for age, gender, body-mass index (BMI), indication and number of instrumented levels. Mean DPA at end of sighting and end of procedure was respectively 147.4 cGy.cm² and 230.9 cGy.cm² in the control group and 171.1 cGy.cm² and 280.7 cGy.cm² in the PediGuard group (p> 0.05). Screw positioning on CT was comparable in the 2 groups.

CONCLUSION

In the present study, the PediGuard device did not reduce intraoperative radiation dose. The correlation between radiation dose and BMI was confirmed.

LEVEL OF EVIDENCE

II; prospective randomized study.

Bone conductivity and spine fluoroscopy, Hand-Eye-Ear dialogue, during pedicle screw positioning: a new human cognitive system for precision and radiation-decrease; better than artificial intelligence and machine learning system?

PURPOSE

There is an increasing need for pedicle screw positioning while decreasing radiation exposure. This study compares intra-operative radiation dose using posterior internal fixation using impedancemetry-guided pedicle positioning by the Pediguard system versus standard free-hand sighting when surgery was performed with a trainee or expert surgeon.

MATERIAL AND METHODS

Using the electrical properties of bone, the Pediguard detects iatrogenic penetration of the pedicle wall and gives auditory feedback to the surgeon. A single centre, two surgeons (one experienced and the other novice) conducted a continuous prospective randomized study for one year. Twenty patients were randomized into one group (free-hand control group) receiving pedicle instrumentation without the use of the Pediguard and the second group receiving pedicle instrumentation with the use of the Pediguard. The total screw placement times and fluoroscopic times for each screw was recorded and pedicle screw position was analyzed on post-operative CT scan.

RESULTS

Among the 104 screwed pedicles, 22 unrecognized perforations were detected by CT scan, while no perforation signal was observed intra-operatively. Only one perforation was greater than 2 mm. The overall screwing time was 4.33 ± 1.2 minutes per screw for experienced surgeon and 5.84 ± 2.5 minutes per screw for the novice. Pediguard did not increased significantly the time (0.3 mn per screw) for the experienced surgeon, but the time with Pediguard was longer (2 mn more per screw) for the novice surgeon, particularly at the thoracic level. The overall fluoroscopic average time per screw for the experienced surgeon is 5.8 ± 2.3 s and 10.4 ± 4.5 s for the novice surgeon. For the novice surgeon, radiation time reduced from 12 (without Pediguard) to 6 s (with Pediguard). There was no significant difference for the experienced surgeon in terms of improvement in radiation time with the use of Pediguard.

CONCLUSION

The overall time was longer for the novice surgeon with the Pediguard system, but allowed to decrease by 50% the fluoroscopy time.

Comparing radiation dose of image-guided techniques in lumbar fusion surgery with pedicle screw insertion; A systematic review

Background Context

Fluoroscopic devices can be used to visualize subcutaneous and osseous tissue, a useful feature during pedicle screw insertion in lumbar fusion surgery. It is important that both patient and surgeon are exposed as little as possible, since these devices use potential harmful ionizing radiation.

Purpose

This study aims to compare radiation exposure of different image-guided techniques in lumbar fusion surgery with pedicle screw insertion.

Study Design

Systematic review.

Methods

Cochrane, Embase, PubMed and Web of Science databases were used to acquire relevant studies. Eligibility criteria were lumbar and/or sacral spine, pedicle screw, mGray and/or Sievert and/or mrem, radiation dose and/or radiation exposure. Image-guided techniques were divided in five groups: conventional C-arm, C-arm navigation, C-arm robotic, O-arm navigation and O-arm robotic. Comparisons were made based on effective dose for patients and surgeons, absorbed dose for patients and surgeons and exposure. Risk of bias was assessed using the 2017 Cochrane Risk of Bias tool on RCTs and the Cochrane ROBINS-I tool on NRCTs. Level of evidence was assessed using the guidelines of Oxford Centre for Evidence-based Medicine 2011.

Results

A total of 1423 studies were identified of which 38 were included in the analysis and assigned to one of the five groups. Results of radiation dose per procedure and per pedicle screw were described in dose ranges. Conventional C-arm appeared to result in higher effective dose for surgeons, higher absorbed dose for patients and higher exposure, compared to C-arm navigation/robotic and O-arm navigation/robotic. Level of evidence was 3 to 4 in 29 studies. Risk of bias of RCTs was intermediate, mostly due to inadequate blinding. Overall risk of bias score in NRCTs was determined as 'serious'.

Conclusions

Ranges of radiation doses using different modalities during pedicle screw insertion in lumbar fusion surgery are wide. Based on the highest numbers in the ranges, conventional C-arm tends to lead to a higher effective dose for surgeons, higher absorbed dose for patients and higher exposure, compared to C-arm-, and O-arm navigation/robotic. The level of evidence is low and risk of bias is fairly high. In future studies, heterogeneity should be limited by standardizing measurement methods and thoroughly describing the image-guided technique settings.

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.

Posterior minimally invasive scoliosis surgery versus the standard posterior approach for the management of adolescent idiopathic scoliosis: an updated meta-analysis

Background

Surgical management of adolescent idiopathic scoliosis (AIS) can be performed using standard posterior spinal fusion (PSF) or with a posterior minimally invasive approach. Minimally invasive scoliosis surgery (MISS) has several theoretical advantages, such as less tissue dissection, less blood loss, and earlier recovery. However, the difference in safety and effectiveness between MISS and PSF still needs to be clarified. This updated meta-analysis aimed to compare the outcomes of MISS and standard PSF for the management of AIS.

Methods

A comprehensive literature search of PubMed, EMBASE, MEDLINE, and Cochrane Library without time restriction was performed to identify relevant studies. MISS and PSF were compared in terms of radiographic parameters, estimated blood loss (EBL), blood transfusion rate, operative time (ORT), length of hospital stay (LOS), overall Scoliosis Research Society-22 (SRS-22) score, postoperative pain, and complication rate.

Results

A total of seven studies comprising 767 patients (329 MISS and 438 PSF) with AIS were included. MISS and PSF yielded comparable deformity correction at the last follow-up. There were no significant differences in the overall SRS-22 scores or complication rates between the groups. Nevertheless, greater restoration of thoracic kyphosis (WMD, 2.98; 95% CI 0.58 to 5.37, P = 0.015), less EBL (WMD, −218.76; 95% CI −256.41 to −181.11, P < 0.001), a lower blood transfusion rate (RR, 0.31; 95% CI 0.20 to 0.48, P < 0.001), a shorter LOS (WMD, −1.48; 95% CI −2.48 to −0.48, P = 0.004), less postoperative pain (WMD, 0.57; 95% CI 0.16 to 0.98, P = 0.006), and a longer ORT (WMD, 84.85; 95% CI 33.30 to 136.40, P = 0.001) were observed in the MISS group.

Conclusion

Despite its inherent technical challenges, MISS is a feasible and effective alternative to standard PSF for AIS patients with moderate and flexible curves. MISS was associated with adequate deformity correction, better restoration of sagittal alignment, less EBL, fewer transfusions, shorter LOS, and better pain management compared to PSF. Further research is required to determine the detailed indications for the MISS procedure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-02954-4.

Effectiveness of Tirobot-assisted vertebroplasty in treating thoracolumbar osteoporotic compression fracture

Background

Percutaneous kyphoplasty is the main method in the treatment of thoracolumbar osteoporotic compression fractures. However, much radiation exposure during the operation harms the health of surgeons and patients. In addition, the accuracy of this surgery still needs to be improved. This study aimed to assess the radiation exposure and clinical efficacy of Tirobot-assisted vertebroplasty in treating thoracolumbar osteoporotic compression fracture.

Methods

Included in this retrospective cohort study were 60 patients (60–90 years) who had undergone unilateral vertebroplasty for thoracolumbar osteoporotic compression fracture at our hospital between June 2019 and June 2020. All showed no systemic diseases and were assigned to Tirobot group (treated with Tirobot-assisted approach) and control group (treated with traditional approach). Fluoroscopic frequency, operative duration, length of stay (LOS), post-operative complications (cement leakage, infection, and thrombosis), and pre-operative and pre-discharge indexes (VAS score, JOA score, and Cobb’s angle) were compared.

Results

The fluoroscopic frequency (P < 0.001) and post-operative complications (P = 0.035) in Tirobot group were significantly lower than those in control group. The operative duration and LOS in the Tirobot group were shorter than those in the control group, but the differences were not statistically significant (P = 0.183). Pre-discharge VAS score and Cobb’s angle decreased, and JOA increased after surgeries in both groups. These three indexes showed a significant difference after surgery in each group (P < 0.001), but not between groups (P_VAS = 0.175, P_Cobb’s = 0.585, P_JOA = 0.448).

Conclusion

The Tirobot-assisted vertebroplasty can reduce surgery-related trauma, post-operative complications, and patients’ and operators’ exposure to radiation. As a safe and effective strategy, this surgery can realize the quick recovery from thoracolumbar osteoporotic compression fracture.

Keyhole Foraminotomy via a Percutaneous Posterior Full-endoscopic Approach for Cervical Radiculopathy: An Advanced Procedure and Clinical Study

Endoscopic cervical foraminotomy is increasingly used for cervical spondylotic radiculopathy (CSR), but there is great concern about radiation exposure because of the heavy dependence of this surgical method on fluoroscopy. The objective of this study was to introduce in detail an advanced surgical technique of keyhole foraminotomy via a percutaneous posterior full-endoscopic approach as a treatment for CSR and investigate its clinical outcomes. We retrospectively reviewed 33 consecutive patients with CSR who underwent keyhole foraminotomy via a percutaneous posterior full-endoscopic approach from October 2015 to April 2017. The patients' general characteristics, including operative time, blood loss, hospital stay, complications, and recurrence, were obtained. Clinical outcomes were evaluated using the visual analogue scale (VAS) for radicular pain, the neck disability index (NDI) for functional assessment, and the modified MacNab criteria for patient satisfaction. All operations were successfully performed (mean operation time, 62 min), with no measurable blood loss or severe related complications. The mean follow-up was 25 months. The VAS and NDI scores were significantly improved as compared with those in the preoperative period (preoperative vs. final follow-up: 7.6±1.6 vs. 3.83±7.34 for VAS, P<0.01; 69.5%±10.5% vs. 17.54%±13.40% for NDI, P<0.01). Of the 33 patients, 32 (97.0%) had good-to-excellent global outcomes and all patients obtained symptomatic improvement. In conclusion, keyhole foraminotomy via a percutaneous posterior full-endoscopic approach is an efficient, safe, and feasible procedure for the treatment of CSR. Its simplified single-step blunt incision for localization appears to decrease radiation exposure risks.

Intraoperative risks of radiation exposure for the surgeon and patient

Intraoperative radiological imaging serves an essential role in many spine surgery procedures. It is critical that patients, staff and physicians have an adequate understanding of the risks and benefits associated with radiation exposure for all involved. In this review, we briefly introduce the current trends associated with intraoperative radiological imaging. With the increased utilization of minimally invasive spine surgery (MIS) techniques, the benefits of intraoperative imaging have become even more important. Less surgical exposure, however, often equates to an increased requirement for intraoperative imaging. Understanding the conventions for radiation measurement, radiological fundamental concepts, along with deterministic or stochastic effects gives a framework for conceptualizing how radiation exposure relates to the risk of various sequela. Additionally, we describe the various options surgeons have for intraoperative imaging modalities including those based on conventional fluoroscopy, computer tomography, and magnetic resonance imaging. We also describe different ways to prevent unnecessary radiation exposure including dose reduction, better education, and use of personal protective equipment (PPE). Finally, we conclude with a reflection on the progress that has been made to limit intraoperative radiation exposure and the promise of future technology and policy.

PATIENT SIZE INDICES AND DOSE IN FLUOROSCOPICALLY GUIDED LUMBAR DISCECTOMY AND FUSION: A PRELIMINARY STUDY

Patient dose values varied significantly during interventional procedures, mainly due to the patient size, operators' choices and clinical complexity. In this study, the effect of applying a previously described and validated size-correction method to normalise kerma-area product (KAP) and average KAP rate values of the whole procedure (KAP rate) and isolate variations in dose due to the patient size and complexity, during lumbar discectomy and fusion (LDF) procedures, was investigated. Fluoroscopy time (FT), KAP, KAP rate and patient size data (weight, height and equivalent diameter) were recorded, for 96 patients who underwent single or multilevel LDF procedures by three senior neurosurgeons, defining three different patient groups (surgeon 1, surgeon 2, surgeon 3). Simple linear regression and coefficients of determination were used to investigate the relationship between uncorrected and corrected KAP and KAP rate values and patient size indices in these groups. The results showed that the size correction decreased the influence of patient size and could contribute to the isolation of the variations in patient dose due to the patient size. From this point of view, dose surveys during lumbar spine interventions may include dosimetric data from all patients independently of their body size and not only for standard-sized patients, providing the advantage of accessible data collection for the establishment of local dose reference levels and optimisation purposes, within the framework of the radiation protection program in the Neurosurgery Department.

DO THE BMI AND SURGEON INFLUENCE THE PATIENT DOSE IN FLUOROSCOPICALLY GUIDED LUMBAR DISCECTOMY AND FUSION?☆

A survey was conducted to evaluate the role of the surgeon and the patients' body size, on patient radiation dose in fluoroscopically guided lumbar discectomy and fusion (LDF) procedures. Fluoroscopy time (FT), kerma area product (KAP), cumulative dose (CD), as well as anatomical and technical data were recorded for 100 patients, who underwent single or multi-level posterior LDF, which was carried out by three senior neurosurgeons utilising a C-arm fluoroscopy system. The patients were divided into three groups based on the body mass index (BMI) values (normal, overweight, obese) and the neurosurgeon that performed each procedure (surgeon 1, surgeon 2, surgeon 3). Entrance surface dose (ESD) was estimated based on KAP values and exposure data, while the effective dose (ED) was estimated utilising the KAP values and appropriate conversion coefficients. The mean FT, KAP, CD, ESD and ED values were 11.7 s, 0.65 Gy cm2, 2.96 mGy, 11.7 mGy and 0.08 mSv for normal patients, 22.1 s, 0.94 Gy cm2, 4.27 mGy, 21.4 mGy and 0.11 mSv for overweight patients and 67.7 s, 3.59 Gy cm2, 17.79 mGy, 107.2 mGy and 0.44 mSv for obese patients. The corresponding values were 21.5 s, 0.77 Gy cm2, 3.51 mGy, 17.5 mGy, 0.09 mSv for the first, 23.0 s, 1.44 Gy cm2, 6.52 mGy, 30.2 mGy, 0.18 mSv for the second and 14.2 s, 0.64 Gy cm2, 2.91 mGy, 17.0 mGy, 0.08 mSv for the third surgeon. Overweight patients received 83% and 38% higher ESD and ED, while obese patients 816% and 450%, compared to normal patients, respectively. The CD values should be implemented with caution, as a skin dose indicator, for all patient sizes. The weight-FT product could be useful in estimating KAP during LDF procedures. The third surgeon achieved the lowest dose values. Although the first surgeon had the same FT with the second surgeon, the corresponding dose values were decreased by 50%. The differences in FT, KAP, CD and ED values among the groups of patients studied were not statistically significant (Kruskal-Wallis test, p > 0.05), although the p-values were close to the threshold of statistical significance. The pairwise comparisons showed statistically significant differences for KAP, CD and ED values between obese and normal patients and between surgeon 1 and surgeon 3 (Mann-Whitney test, p < 0.05). The ESD values showed statistically significant differences among the BMI-based groups and among the surgeon-based groups studied (Kruskal-Wallis test, p < 0.05). This fact can be attributed to the better implementation of the fluoroscopy system technical parameters concerning the patients' size, clinical conditions and complexity of the procedures. Training and awareness of neurosurgeons on radiation protection issues are of critical importance; however, further studies should be performed towards optimisation procedures regarding patient dose.

Evaluation of surgeon and patient radiation exposure by imaging technology in patients undergoing thoracolumbar fusion: systematic review of the literature

BACKGROUND CONTEXT

Minimally invasive spine techniques are becoming increasingly popular owing to their ability to reduce operative morbidity and recovery times. The downside to these new procedures is their need for intraoperative radiation guidance.

PURPOSE

To establish which technologies provide the lowest radiation exposure to both patient and surgeon.

STUDY DESIGN/SETTING

Systematic review OUTCOME MEASURES: Average intraoperative radiation exposure (in mSv per screw placed) to surgeon and patient. Average fluoroscopy time per screw placed.

METHODS

We reviewed the available English medical literature to identify all articles reporting patient and/or surgeon radiation exposure in patients undergoing image-guided thoracolumbar instrumentation. Quantitative meta-analysis was performed for studies providing radiation exposure or fluoroscopy use per screw placed to determine which navigation modality was associated with the lowest intraoperative radiation exposure. Values on meta-analysis were reported as mean ± standard deviation.

RESULTS

We identified 4956 unique articles, of which 85 met inclusion/exclusion criteria. Forty-one articles were included in the meta-analysis. Patient radiation exposure per screw placed for each modality was: conventional fluoroscopy without navigation (0.26±0.38 mSv), conventional fluoroscopy with pre-operative CT-based navigation (0.027±0.010 mSv), intraoperative CT-based navigation (1.20±0.91 mSv), and robot-assisted instrumentation (0.04±0.30 mSv). Values for fluoroscopy used per screw were: conventional fluoroscopy without navigation (11.1±9.0 seconds), conventional fluoroscopy with navigation (7.20±3.93 s), 3D fluoroscopy (16.2±9.6 s), intraoperative CT-based navigation (19.96±17.09 s), and robot-assistance (20.07±17.22 s). Surgeon dose per screw: conventional fluoroscopy without navigation (6.0±7.9 × 10^-3 mSv), conventional fluoroscopy with navigation (1.8±2.5 × 10^-3 mSv), 3D Fluoroscopy (0.3±1.9 × 10^-3 mSv), intraoperative CT-based navigation (0±0 mSv), and robot-assisted instrumentation (2.0±4.0 × 10^-3 mSv).

CONCLUSION

All image guidance modalities are associated with surgeon radiation exposures well below current safety limits. Intraoperative CT-based (iCT) navigation produces the lowest radiation exposure to surgeon albeit at the cost of increased radiation exposure to the patient relative to conventional fluoroscopy-based methods.