Surgeons' exposure to radiation in single- and multi-level minimally invasive transforaminal lumbar interbody fusion; a prospective study

A Novel Intraoperative CT Navigation System for Spinal Fusion Surgery in Lumbar Degenerative Disease: Accuracy and Safety of Pedicle Screw Placement

Background: In recent years, intraoperative computed tomography (CT) navigation has become widely used for the insertion of pedicle screws in spinal fusion surgery. However, conventional intraoperative CT navigation may be impaired by infrared interference between the infrared camera and surgical instruments, which can lead to the misplacement of pedicle screws. Recently, a novel intraoperative CT navigation system, NextAR, has been developed. It uses a small infrared camera mounted on surgical instruments within the surgical field. NextAR navigation can minimize the problem of infrared interference and be expected to improve the accuracy of pedicle screw placement. Methods: This study investigated the accuracy of pedicle screw insertion under NextAR navigation in spinal fusion surgery for lumbar degenerative diseases. The accuracy of pedicle screw placement was evaluated in 15 consecutive patients using a CT grading scale. Results: Screw perforation occurred in only 1 of the total 70 screws (1.4%). Specifically, there was one grade 1 perforation within 2 mm, but no perforations larger than 2 mm. There were no reoperations or neurological complications due to screw misplacement. Conclusions: NextAR navigation can provide high accuracy for pedicle screw insertion and help ensure safe spinal fusion surgery for lumbar degenerative diseases.

Eye lens dose in spine surgeons during myelography procedures: a dosimetry study

To determine the eye lens dose (3 mm dose equivalent [Hp(3)]) received by spine surgeons during myelography and evaluate the effectiveness of radiation-protective glasses and x-ray tube system positioning in reducing radiation exposure. This study included spine surgeons who performed myelography using over- or under-table x-ray tube systems. Hp(3) was measured for each examination using a radio-photoluminescence glass dosimeter (GD-352M) mounted on radiation-protective glass. This study identified significantly high Hp(3) levels, especially in the right eye lens in spinal surgeons. The median Hp(3) values in the right eye were 524 (391-719) and 58 (42-83)μSv/examination for over- and under-table x-ray tube systems, respectively. Further, Hp(3)AK, which was obtained by dividing the cumulative air kerma from Hp(3), was 8.09 (6.69-10.21) and 5.11 (4.06-6.31)μSv mGy-1for the over- and under-table x-ray tube systems, respectively. Implementing radiation-protective glasses resulted in dose reduction rates of 54% (50%-57%) and 54% (51%-60%) for the over- and under-table x-ray tube systems, respectively. The use of radiation protection glasses significantly reduced the radiation dose in the eye lens during myelography, with the most effective measures being the combination of using radiation protection glasses and an under-table x-ray tube system.

Free-Hand MIS TLIF without 3D Navigation-How to Achieve Low Radiation Exposure for Both Surgeon and Patient

BACKGROUND

Transforaminal lumbar interbody fusion (TLIF) is one of the most frequently performed spinal fusion techniques, and this minimally invasive (MIS) approach has advantages over the traditional open approach. A drawback is the higher radiation exposure for the surgeon when conventional fluoroscopy (2D-fluoroscopy) is used. While computer-assisted navigation (CAN) reduce the surgeon's radiation exposure, the patient's exposure is higher. When we investigated 2D-fluoroscopically guided and 3D-navigated MIS TLIF in a randomized controlled trial, we detected low radiation doses for both the surgeon and the patient in the 2D-fluoroscopy group. Therefore, we extended the dataset, and herein, we report the radiation-sparing surgical technique of 2D-fluoroscopy-guided MIS TLIF.

METHODS

Monosegmental and bisegmental MIS TLIF was performed on 24 patients in adherence to advanced radiation protection principles and a radiation-sparing surgical protocol. Dedicated dosemeters recorded patient and surgeon radiation exposure. For safety assessment, pedicle screw accuracy was graded according to the Gertzbein-Robbins classification.

RESULTS

In total, 99 of 102 (97.1%) pedicle screws were correctly positioned (Gertzbein grade A/B). No breach caused neurological symptoms or necessitated revision surgery. The effective radiation dose to the surgeon was 41 ± 12 µSv per segment. Fluoroscopy time was 64 ± 34 s and 75 ± 43 radiographic images per segment were performed. Patient radiation doses at the neck, chest, and umbilical area were 65 ± 40, 123 ± 116, and 823 ± 862 µSv per segment, respectively.

CONCLUSIONS

Using a dedicated radiation-sparing free-hand technique, 2D-fluoroscopy-guided MIS TLIF is successfully achievable with low radiation exposure to both the surgeon and the patient. With this technique, the maximum annual radiation exposure to the surgeon will not be exceeded, even with workday use.

Intraoperative Fluoroscopy Radiation Using OEC 9900 Elite C-arm: Risk and Method for Decreasing Exposure

ABSTRACT

The use of intraoperative fluoroscopy in surgery produces scattered radiation that can expose all operating room personnel to measurable and, in some cases, substantial radiation doses. The goal of this work is to assess and document potential radiation doses to various staff positions in a simulated standard operating room environment. Adult-sized mannequins wearing standard lead protective aprons were placed at seven positions around large and small BMI cadavers. Doses were recorded in real time at thyroid level with Bluetooth-enabled dosimeters for a variety of fluoroscope settings and imaging views. A total of 320 images were acquired, resulting in 2,240 dosimeter readings from the seven mannequins. Doses were compared to cumulative air kerma (CAK) calculations provided by the fluoroscope. There was a strong correlation between the CAK and the recorded scattered radiation doses ( P < 0.001). Radiation doses could be reduced by manipulating C-arm manual technique settings [e.g., turning off the automatic exposure control (AEC) and using pulse (PULSE) or low dose (LD) settings]. Staff position and patient size also affected the recorded doses. The highest radiation doses were recorded across all settings for the mannequin positioned immediately adjacent to the C-arm x-ray tube. The larger BMI cadaver generated greater scattered radiation than the smaller BMI cadaver for all views and settings. This work provides suggestions for reducing exposure to operating room personnel beyond standard techniques of reducing beam-on time, increasing the distance from the radiation source, and use of shielding. Simple changes in C-arm settings (turning AEC off, avoiding DS setting, use of PULSE or LD settings) can markedly reduce dose to staff.

Marker Screw Utilization for Minimally Invasive Transforaminal Lumbar Interbody Fusion (MS-MIS TLIF): Promises and Advantages

Background and Objective: Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) has been investigated and shown excellent short- and long-term outcomes. In this paper, we describe a new MIS-TLIF technique and pedicle screw insertion using a marker screw as a guidance method. Moreover, we report perioperative, postoperative, and patient-related outcomes. In addition, this paper outlines major differences in radiation exposure, cost effectiveness and accuracy of Marker Screw Minimally Invasive Transforaminal Interbody Fusion (MS-MIS TLIF) compared to other techniques. We report our technique to share our knowledge and experience with the aim of achieving a better MIS-TLIF that would help both surgeons and patients. Materials and Methods: A prospective case series was conducted between October 2018 and February 2021. Patients undergoing MS-MIS TLIF with marker screws were consecutively included. The surgery did not exceed two levels. The patients’ medical records were reviewed, and the included patients were asked to complete two outcome-questionnaires before surgery and at the six-month visit. The surgical technique is described in this paper. Results: A total of 37 patients were recruited. The mean age was 57.35 ± 12.8 years, and more than half of the patients were females. The most common indications for surgery were degenerative disc disease and spondylolisthesis, with the typical level at L4–5. The operative time was 3.02 ± 0.83 h, while the estimated blood loss was 127.7 ± 71.1 mL. The average time for ambulation and hospitalization was 1 ± 1.1 and 2.84 ± 1.4 days, respectively. The patients described significant improvement in both questionnaires. No screw-related complications or screw revisions were needed up to two years of follow-up. Conclusions: The use of marker screws for pedicle screw placement through a minimally invasive fashion is shown to be a promising technique that can overcome many drawbacks, including cost, operative time, and radiation exposure. Performing MS-MIS TLIF can achieve a 360- degree fusion compared to percutaneous MIS-TLIF.

Protective Attitudes toward Occupational Radiation Exposure among Spine Surgeons in Japan: An Epidemiological Description from the Survey by the Society for Minimally Invasive Spinal Treatment

Background and Objectives: The global trend toward increased protection of medical personnel from occupational radiation exposure requires efforts to promote protection from radiation on a societal scale. To develop effective educational programs to promote radiation protection, we clarify the actual status and stage of behavioral changes of spine surgeons regarding radiation protection. Materials and Methods: We used a web-based questionnaire to collect information on the actual status of radiation protection and stages of behavioral change according to the transtheoretical model. The survey was administered to all members of the Society for Minimally Invasive Spinal Treatment from 5 October to 5 November 2020. Results: Of 324 members of the Society for Minimally Invasive Spinal Treatment, 229 (70.7%) responded. A total of 217 participants were analyzed, excluding 12 respondents who were not exposed to radiation in daily practice. A trunk lead protector was used by 215 (99%) participants, while 113 (53%) preferred an apron-type protector. Dosimeters, thyroid protector, lead glasses, and lead gloves were used by 108 (50%), 116 (53%), 82 (38%), and 64 (29%) participants, respectively. While 202 (93%) participants avoided continuous irradiation, only 120 (55%) were aware of the source of the radiation when determining their position in the room. Regarding the behavioral change stage of radiation protection, 134 (62%) participants were in the action stage, while 37 (17%) had not even reached the contemplation stage. Conclusions: We found that even among the members of the Society for Minimally Invasive Spinal Treatment, protection of all vulnerable body parts was not fully implemented. Thus, development of educational programs that cover the familiar risks of occupational radiation exposure, basic protection methods in the operating room, and the effects of such protection methods on reducing radiation exposure in actual clinical practice is warranted.

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.

Occupational ionizing radiation-induced skin injury among orthopedic surgeons: A clinical survey

BACKGROUND

This study aimed to assess orthopedic surgeons' attitudes and behaviors toward occupational radiation exposure and investigate the prevalence of occupational radiation-induced skin injury among orthopedic surgeons. Similarly, risk factors for the presence of radiation-induced skin injury were investigated.

METHODS

Overall, 108 orthopedic surgeons were administered self-reported questionnaires about occupational radiation exposure, and their hands were then photographed. Their fields of expertise were classified into spine, arthroplasty, sports medicine, hand, oncology, rheumatoid arthritis, pediatric orthopedic, and resident. Dermatologists evaluated the surgeons' skin conditions and classified into 3 grades of injury: grade 0, no clinical symptoms; grade 1, careful observation required; and grade 2, detailed examination required. Logistic regression analysis was performed to investigate the factors related to the presence of radiation-induced skin injury. Crude and adjusted logistic regression analysis using the backward stepwise selection method was similarly conducted. Receiver operating characteristic curve (ROC) analysis was performed to estimate the predictive power of exposure time, occupational period, and accumulated annual exposure time for radiation-induced skin injury.

RESULTS

In total, 93.5% of the surgeons were careful about occupational radiation exposure, of which 76.8% used a dosimeter. Skin changes in the hands were self-reported by 42.5% of the surgeons, and radiation-induced skin injury was diagnosed in 31.4%. The accuracy of the self-reported skin changes was 100% for grade 2 and 61.5% for grade 1. Adjusted regression analysis showed that dermatologists' diagnosis-related factors were self-reported skin changes (odds ratio [OR] 3.1) and spine surgeons (OR 3.2). ROC analysis demonstrated that an occupational period >21 years and an accumulated exposure time >6696 min were considered risk factors, with ORs of 4.07 and 5.99, respectively.

CONCLUSIONS

Orthopedic surgeons, particularly spine surgeons, should be regularly examined by dermatologists early in their careers for early detection of radiation-induced skin injury on the hands.

Association between occupational testicular radiation exposure and lower male sex ratio of offspring among orthopedic surgeons

Background

Exposure to occupational radiation can lower the male sex ratio. However, specific radiation exposure to the testes has not been evaluated.

Objective

This study aimed to examine the association between testicular radiation exposure and lower male sex ratio in children.

Methods

A comprehensive questionnaire survey was administered to 62 full-time male doctors with children aged < 10 years at 5 hospitals. Based on the possibility of testicular radiation exposure 1 year before the child’s birth, participants were assigned to 3 groups as follows: RT (orthopedic surgery), RNT (cardiology/neurosurgery), and N (others). Intergroup differences in the proportion of female children were ascertained, and the female sex ratio (number of female/total number) of each group was compared against the standard value of 0.486. Multivariate logistic regression analysis with a generalized estimating equation was used to model the effects on the probability of female birth while controlling for the correlation among the same fathers.

Results

The study population included 62 fathers and 109 children, 49 were female: 19/27, 11/30, and 19/52 in the RT, RNT, and N group, respectively; the RT group had the highest proportion of females (p = 0.009). The p values for comparisons with the standard sex ratio (0.486) were 0.02, 0.19, and 0.08 for the RT, RNT, and N groups, respectively. Based on the N group, the adjusted odds ratios for the child to be female were 4.40 (95% confidence interval 1.60–2.48) and 1.03 (0.40–2.61) for the RT and RNT groups, respectively.

Conclusions

Our results imply an association between testicular radiation exposure and low male sex ratio of offspring. Confirmatory evidence is needed from larger studies which measure the pre-conceptional doses accumulated in various temporal periods, separating out spermatogonial and spermatid effects.

Comparison of Radiation Exposure Between Anterior, Lateral, and Posterior Interbody Fusion Techniques and the Influence of Patient and Procedural Factors

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

The aim of this study was to elucidate the relative influence of multiple factors on radiation usage for anterior, lateral, and posterior based lumbar interbody fusion techniques.

SUMMARY OF BACKGROUND DATA

There has been substantial global growth in the performance of lumbar interbody fusions, due to evolution of techniques and approaches and increased attention to sagittal alignment. Utilization of intraoperative imaging guidance has similarly expanded, with a predominance of fluoroscopy and consequent increased radiation exposure. There have been no larger-scale studies examining the role of patient and procedural factors in driving radiation exposure across different interbody techniques.

METHODS

We used a clinical registry to review all single-level lumbar interbody fusions performed between January 2016 and October 2020. Operative records were reviewed for the amount of radiation exposure during the procedure. Patient age, biologic sex, body mass index (BMI), operative surgeon, surgical level, surgical time, and fusion technique were recorded. Multivariable adjusted analyses using negative binomial regression were used to account for confounding.

RESULTS

We included 134 interbody fusions; 80 performed with a posterior approach (TLIF/PLIF), 43 via an anterior approach (ALIF) with posterior pedicle fixation, and 9 performed with a lateral approach (LLIF/XLIF). Average radiation per case was 136.4 mGy (SE 17.3) for ALIF, 108.6 mGy (16.9) for LLIF/XLIF, and 60.5 mGy (7.4) for TLIF/PLIF. We identified lateral approaches, increased BMI, minimally invasive techniques, and more caudal operative levels as significantly associated with increased radiation exposure.

CONCLUSION

We identified several novel drivers of radiation exposure during interbody fusion procedures, including the relative importance of technique and the level at which the fusion is performed. More caudal levels of intervention and lateral based techniques had significantly greater radiation exposure.Level of Evidence: 4.

Minimising radiation exposure to the surgeon in minimally invasive spine surgeries: A systematic review of 15 studies

BACKGROUND

Intraoperative imaging in minimally invasive spinal surgeries is associated with significant radiation exposure to surgeons, which overtime can lead to serious health hazards including malignancy. In this study, the authors conducted a systematic review to evaluate the efficacy of navigation assisted fluoroscopy methods on radiation exposure to the surgeon in minimally invasive spine surgeries, percutaneous endoscopic lumbar discectomy/percutaneous endoscopic transforaminal discectomy versus minimally invasive spine transforaminal lumbar interbody fusion (PELD/PETD versus MIS-TLIF).

METHODS

A systematic literature search was conducted using PUBMED/MEDLINE on 20th July, 2020. Inclusion criteria were applied according to study design, surgical technique, spinal region, and language. Data extracted included lumbar segment, average operation time (min), fluoroscopic time (s), and radiation dose (μSV), efficacy of modified navigation versus conventional techniques; on reducing operation, fluoroscopy times and effective radiation dose.

RESULTS

Fifteen studies (ten prospectives, and five retrospectives) were included for quantitative analysis. PELD recorded a shorter operation time (by 126.3min, p<0.001) and fluoroscopic time (by 22.9s, p=0.3) than MIS-TLIF. The highest radiation dose/case (μSV) for both techniques were recorded at the surgeon's: finger, chest, neck and eye. The effective dose for MIS-TLIF was 30μSV higher than PELD. Modified navigation techniques recorded a shorter operation time (by 15.9min, p=0.3); fluoroscopy time (by 289.8s, p=0.3); effective radiation dose (by 169.5μSV, p=0.3) than conventional fluoroscopy methods.

DISCUSSION

This systematic literature review showed that although navigation assisted fluoroscopy techniques are superior to conventional methods in minimising radiation exposure, lack of statistical significance warrants future randomised controlled trials, to solidify their efficacy in reducing radiation related hazards.

Association of occupational direct radiation exposure to the hands with longitudinal melanonychia and hand eczema in spine surgeons: a survey by the society for minimally invasive spinal treatment (MIST)

PURPOSE

To investigate the association between occupational direct radiation exposure to the hands and longitudinal melanonychia (LM) and hand eczema in spine surgeons.

METHODS

A web-based questionnaire survey of the Society for Minimally Invasive Spinal Treatment (MIST) in Japan was conducted. The proportion of LM and hand eczema in hands with high and low-radiation exposure was compared using Fisher's exact test. The odds ratios (ORs) and their 95% confidence intervals (CIs) for the prevalence of LM and hand eczema in the high-radiation exposure hands were calculated using generalized estimating equations for logistic regression as control for the correlation of observations among the same individuals and possible confounders.

RESULTS

Among 324 members of the society, responses were received from 229 members (70.7%). A total of 454 hands from 227 participants were analysed. The prevalence of LM and hand eczema was 43% and 29%, respectively. In a hand-by-hand comparison, more hands had LM in the high-radiation exposure group than the low-radiation exposure group (90 [40%] vs. 39 [17%], respectively, p < 0.001). A similar trend was observed for hand eczema (63 [28%] vs. 33 [15%], respectively, p = 0.001). The adjusted OR for high-radiation exposure hands was 3.18 (95% CI: 2.24-4.52). Consistent results were obtained for hand eczema, with an adjusted OR of 2.26 (95% CI: 1.67-3.06).

CONCLUSION

The present study suggests that direct radiation exposure to physician's hands is associated with LM and hand eczema. Those with LM and radially biased hand eczema may have had high direct radiation exposure.

Radiation Exposure in Minimally Invasive Lumbar Fusion Surgery: A Randomized Controlled Trial Comparing Conventional Fluoroscopy and 3D Fluoroscopy-based Navigation

STUDY DESIGN

Randomized controlled trial.

OBJECTIVE

The aim of this study was to compare the dosemetrically determined radiation exposure of surgeon and patient during minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) using conventional 2D fluoroscopy (FLUORO) or 3D fluoroscopy-based navigation (NAV).

SUMMARY OF BACKGROUND DATA

MIS TLIF was shown to exhibit higher radiation exposures compared to open techniques. In particular, the routinely exposed surgeon encounters the risks of increased radiation doses. With the additional use of intraoperative 3D navigation, major steps of the operation can be performed without exposing the operating room staff to ionizing radiation.

METHODS

Forty-four patients undergoing monosegmental MIS TLIF were randomized into the two intraoperative imaging technique groups (FLUORO or NAV). The primary endpoint was the radiation exposure of the surgeon; the secondary endpoints were the radiation exposure of the patient and C-arm readings.

RESULTS

After exclusion of three patients, 41 patients were analyzed. In general, the average radiation exposure of the surgeon was lower in the NAV group without being statistically significant. The radiation exposure of the patient was significantly higher in the NAV group at all dosemeter sites. The average fluoroscopy time was 63 ± 36 versus 109 ± 31 sec (FLUORO versus NAV group, P < 0.001).

CONCLUSION

The additional use of intraoperative 3D fluoroscopy-based navigation compared to conventional 2D fluoroscopy alone showed a nonsignificant reduction of the radiation exposure of the surgeon in monosegmental MIS TLIF, while increasing the radiation exposure of the patient.

LEVEL OF EVIDENCE

1.

Ultrasound-guided total dorsal ramus block for the treatment of chronic low back pain

Background:

To reduce the risk of radiation exposure, we explored whether the total dorsal ramus block can be performed under ultrasound guidance. We evaluated the accuracy and effect of ultrasound-guided total dorsal ramus block for chronic low back pain.

Methods:

Accuracy of ultrasound guidance after total dorsal ramus block to the L4–L5 level was evaluated using fluoroscopy ( n = 5). A second group was assigned into two groups: ultrasound-guided group ( n = 19) or fluoroscopy-guided group ( n = 18). The effects and adverse events were compared.

Results:

In all cases, the fluoroscopic findings revealed an accurate injection at the L5 level. Significant alleviation of pain was observed after ultrasound-guided total dorsal ramus block, and comparable effectiveness was observed with both ultrasound guidance and fluoroscopic guidance. There were no complications.

Conclusions:

The ultrasound-guided total dorsal ramus block may sufficiently block all three branches of the lumbar dorsal ramus at the targeted level resulting in significant pain reduction.

C-Arm-Free Circumferential Minimally Invasive Surgery for Adult Spinal Deformity: Technical Note

BACKGROUND

Circumferential minimally invasive surgery (cMIS), as a technique for reducing the complications of adult spinal deformity surgery, is receiving considerable attention. Conventional cMIS is performed using intraoperative fluoroscopy. In this work, we describe a new cMIS technique without using C-arm fluoroscopy for correcting adult spinal deformities.

CASE DESCRIPTION

A 70-year-old woman with symptomatic adult spinal deformity was referred to our hospital. The patient's daily life has been affected by severe low back pain for more than 4 years. The surgery was performed without C-arm fluoroscopy. The percutaneous pedicle screws and intervertebral cages were inserted only under navigation guidance. The patient was successfully treated with surgery, and her low back pain was well controlled. Her clinical outcomes were as follows: Oswestry Disability Index improved from 64% to 14% and the low back pain visual analog scale score improved from 75 mm to 24 mm at 1 year of final follow-up.

CONCLUSIONS

C-arm-free cMIS for adult spinal deformity is a useful technique that reduces percutaneous screw and cage misplacement. With this new technique, the surgeons and the operation room staff can avoid the risk of an adverse event of intraoperative radiation.

Effect of Instrument Navigation on C-arm Radiation and Time during Spinal Procedures: A Clinical Evaluation

Introduction

As minimally invasive spine surgery gains popularity, a focused effort must be made to reduce intraoperative radiation exposure to levels as low as reasonably achievable. Here, we demonstrate the clinical efficacy of a novel technology to aid in instrument navigation that aims to reduce intraoperative radiation exposure, number of fluoroscopic images, and time required to perform the most radiation intensive portions of a multitude of spinal procedures.

Methods

An internally randomized controlled study was performed over a 1-month period in order to clinically evaluate the effect of the C-arm assisted instrument tracking system, TrackX, on surgeon workflow, time, and radiation emitted. Three surgeons performed multiple spinal procedures on a total of 10 study patients and an additional 3 control patients. The surgeries encompassed minimally invasive spinal techniques and spanned extreme lateral interbody fusion, oblique lumbar interbody fusion, transforaminal lumbar interbody fusion along with percutaneous iliac screw placement, hardware removal, and kyphoplasty. The tasks studied included skin marking, first dilator insertion, localization for hardware placement and hardware removal.

Results

Overall radiation reduction was 83% (P < .0001). Overall reduction in x-rays taken was 78% (P < .0001). Overall time reduction was 81% (P = .0003). Statistical significance held for each surgeon studied and for nearly every procedure type. In these 10 study procedures, over 2 hours of overall operating room time was saved, all while requiring negligible set up time and no system calibration or supplementary x-rays to be taken. There were no adverse outcomes for any study patient, and there was no case where TrackX was not able to successfully complete a given portion of a procedure.

Conclusions

TrackX instrument navigation is a clinically efficacious and accurate instrument tracking modality. This is the first instrument navigational technology that reduces radiation exposure and images required to complete a procedure while decreasing operative time. TrackX thus allows increased surgical efficiency while increasing operative efficiency and improving intraoperative safety.

Level of Evidence

2.

Vertebroplasty with posterior spinal fusion for osteoporotic vertebral fracture using computer-assisted rod contouring system: A new minimally invasive technique

•

Surgical treatment of osteoporotic vertebral fracture (OVF) is challenging.

•

A new minimally invasive technique of posterior spinal fusion was performed for OVF.

•

This technique would be beneficial for elderly or immunocompromised patients.

Introduction

Surgical treatment of osteoporotic vertebral fracture (OVF) has been challenging for spine surgeons, because there are potential risks of instrumentation failure; such as screw loosening, loss of correction, or pseudarthrosis, due to bone fragility in elderly patients with several comorbidities.

Presentation of case

A 68-year-old female presented with a severe low back pain and bilateral thigh pain. She had a history of systemic scleroderma, which was complicated by interstitial lung disease. Although she initially underwent non-surgical treatment with bracing for 7 months, her symptoms had progressively deteriorated, and her radiographs showed non-union at L1 and progressive kyphotic deformity at the thoracolumbar spine. Because an anterior approach was inadvisable due to interstitial lung disease, vertebroplasty with posterior spinal fusion was performed using percutaneous pedicle screws (PPS) at the upper most and lowest instrumented vertebra combined with sublaminar taping and computer-assisted rod contouring system. Good bony union was achieved with no screw loosening at 1-year follow-up.

Discussion

Various surgical procedures have been applied according to the fracture type or medical condition of the patient. Minimally invasive posterior spinal fusion would be a less invasive approach in patients with poor medical condition. PPS can prevent the excessive dissection of paravertebral muscles, and this is especially advantageous at the proximal and distal end of long constructs. A recent computer-assisted rod contouring system accurately matches each screw head resulting in reduced strength of the screw-bone interface.

Conclusion

This technique would be beneficial in the elderly or immunocompromised patients with OVF.

Surgeon and staff radiation exposure in minimally invasive spinal surgery: prospective series using a personal dosimeter

OBJECTIVE

The level of radiation awareness by surgeons and residents in spinal surgery does not match the ubiquity of fluoroscopy in operating rooms in the United States. The present method of monitoring radiation exposure may contribute to the current deficiency in radiation awareness. Current dosimeters involve a considerable lag from the time that the surgical team is exposed to radiation to the time that they are provided with that exposure data. The objective of the current study was to assess the feasibility of monitoring radiation exposure in operating room personnel during lateral transpsoas lumbar interbody fusion (LLIF) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) procedures by using a wearable personal device with real-time feedback.

METHODS

Operating room staff participating in minimally invasive surgical procedures under a single surgeon during a 6-month period were prospectively enrolled in this study. All radiation dose exposures were recorded for each member of the surgical team (surgeon, assistant surgeon, scrub nurse, and circulating nurse) using a personal dosimeter (DoseAware). Radiation doses were recorded in microsieverts (μSv). Comparisons between groups were made using ANOVA with the Tukey post hoc test and Student t-test.

RESULTS

Thirty-nine patients underwent interbody fusions: 25 underwent LLIF procedures (14 LLIF alone, 11 LLIF with percutaneous screw placement [PSP]) and 14 underwent MI-TLIF. For each operative scenario per spinal level, the surgeon experienced significantly higher (p < 0.035) average radiation exposure (LLIF: 167.9 μSv, LLIF+PSP: 424.2 μSv, MI-TLIF: 397.9 μSv) than other members of the team, followed by the assistant surgeon (LLIF: 149.7 μSv, LLIF+PSP: 242.3 μSv, MI-TLIF: 274.9 μSv). The scrub nurse (LLIF: 15.4 μSv, LLIF+PSP: 125.7 μSv, MI-TLIF: 183.0 μSv) and circulating nurse (LLIF: 1.2 μSv, LLIF+PSP: 9.2 μSv, MI-TLIF: 102.3 μSv) experienced significantly lower exposures. Radiation exposure was not correlated with the patient's body mass index (p ≥ 0.233); however, it was positively correlated with increasing patient age (p ≤ 0.004).

CONCLUSIONS

Real-time monitoring of radiation exposure is currently feasible and shortens the time between exposure and the availability of information regarding that exposure. A shortened feedback loop that offers more reliable and immediate data would conceivably raise the level of concern for radiation exposure in spinal surgeries and could alter patterns of behavior, leading to decreased exposures. Further studies are ongoing to determine the effect of real-time dosimetry in spinal surgery.

C-arm fluoroscopy for tracheal intubation in a patient with severe cervical spine pathology

Tracheal intubation is challenging in patients with severe cervical spine pathology. In such cases, awake fiberoptic intubation is the gold standard and safest option for tracheal intubation. However, this technique requires the patient's understanding and cooperation, and therefore, may be contraindicated in patients with refusal or poor tolerance. Herein, we report successful orotracheal intubation in a patient with limited mouth opening and severe cervical spine rigidity under general anesthesia using an extraglottic airway device and a gum-elastic bougie under C-arm fluoroscopic guidance.

A protective method to reduce radiation exposure to the surgeon during endoscopic lumbar spine surgery

BACKGROUND

Endoscopic lumbar spine surgery is a minimally invasive technique that requires intraoperative fluoroscopic imaging. Fluoroscopy is a source of ionizing radiation, and exposure of the surgeon to this radiation has a risk for radiation-induced morbidities. To reduce this radiation exposure, we developed a protective method that can be used during endoscopic lumbar spine surgery. The purpose of the study was to determine the effectiveness of this method.

METHODS

A prospective interventional study was performed, in which the primary outcome was radiation exposure to the surgeon [Sievert (Sv)] per case. This was measured using a radiation badge at the levels of the neck, chest, and abdomen on the surface of a protector for the surgeon in 18 endoscopic lumbar spine surgeries, including 9 each with the radiation protection method and the conventional method. Data were also collected for age, gender, body mass index, operative side, and total fluoroscopy time. Primary outcomes were compared in cases that used the radiation protection method and the conventional method.

RESULTS

The mean radiation exposures to the surgeon at the neck, chest, and abdomen were 1.0, 0.8 and 0.7 µSv, respectively, using the radiation protection method, and 3.2, 10.8, and 10.2 µSv, respectively, using the conventional method. The differences in exposure at all three points were significant (P=0.013, P<0.001, P<0.001, respectively).

CONCLUSIONS

These results show the effectiveness of the radiation protection method developed to reduce exposure of the surgeon to radiation during endoscopic lumbar spine surgery.

Does nonexistent of your hands on the screen guarantee no radiation exposure to your body? - Study on exposure of the practitioner's hands to radiation during C-arm fluoroscopy-guided injections and effectiveness of a new shielding device

Observational phantom study.This study aimed to evaluate the radiation exposure dose of practitioner's hands when performing C-arm guided procedures and to determine the usefulness of our newly designed radiation shielding device.C-arm guided procedures including lumbar transforaminal epidural steroid injections (TFESIs) are commonly used for pain control induced by lumbar radiculopathy. The practitioner's hands are vulnerable to radiation exposure because of the long exposure time and short distance from the radiation resource. No studies to date have reported the cumulative exposure of the physician's hands according to location and exposure time.Using a chest phantom irradiated with X-rays under lumbar TFESI conditions, cumulative scatter radiation dose was measured at 36 points using a dosimeter. The measurements were checked at 1, 3, 5, 10 minutes of radiation exposure. The experiment was repeated using our newly designed shielding device.Significant radiation accumulation was observed in the field where the practitioner's hands might be placed during C-arm guided procedures. The further the distance from the radiation resource and the shorter the exposure time, the smaller was the cumulative radiation expose dose. The new shielding device showed an excellent shielding rate (66.0%-99.9%) when the dosimeter was within the shielding range. However, at some points, increased accumulated radiation exposure dose was observed, although the dosimeter was within the range of the shielding device.To reduce radiation exposure of the practitioner's hands when performing C-arm-guided procedures, the radiation exposure time should be decreased and a greater distance from the radiation resource should be maintained. When using our shielding device, placing the hand close to the device surface and minimizing the time using fluoroscopy minimized the radiation exposure of the hand.

Clinical and Radiographic Evaluation of Multilevel Lateral Lumbar Interbody Fusion in Adult Degenerative Scoliosis

STUDY DESIGN

Retrospective review of prospective data.

OBJECTIVE

The objective of this study was to describe the clinical, radiographic, and complication-related outcomes through ≥1-year of 27 patients who underwent lateral lumbar interbody fusion (LLIF) with posterior instrumentation to treat ≥3 contiguous levels of degenerative lumbar scoliosis.

SUMMARY OF BACKGROUND DATA

Multilevel disease has traditionally been treated with open posterior fusion. Literature on multilevel LLIF is limited. We present our experience with utilizing LLIF to treat multilevel degenerative scoliosis.

METHODS

Clinical outcomes were evaluated using VAS, SF-12, and ODI. Radiographic outcomes included pelvic tilt, pelvic incidence, lumbar lordosis, pelvic incidence-lumbar lordosis mismatch, Cobb angle, and cage subsidence. Perioperative and long-term complications through the ≥1-year final-postoperative visit were reviewed; transient neurological disturbances were assessed independently. Demographic, comorbidity, operative, and recovery variables, including opioid use, were explored for association with primary outcomes.

RESULTS

Mean time to final-postoperative visit was 22.5 months; levels treated with LLIF per patient, 3.7; age, 66 years; and lateral operative time, 203 minutes. EBL was ≤100 mL in 74% of cases. Clinical outcomes remained significantly improved at ≥1-year. Cobb angle was corrected from 21.1 to 7.9 degrees (P<0.001), lordosis from 47.3 to 52.6 degrees (P<0.001), and mismatch from 11.4 to 6.4 degrees (P=0.003). High-grade subsidence occurred in 3 patients. Subsidence did not significantly impact primary outcomes. In total, 11.1% returned to the operating room for complication-related intervention over nearly 2-years; 37% experienced complications. Experiencing a complication was associated with having an open-posterior portion (P=0.048), but not with number of LLIF levels treated, or with clinical or radiographic outcomes. No patients experienced protracted neurological deficits; psoas weakness was associated with increased lateral operative time (P=0.049) and decreased surgeon experience (P=0.028).

CONCLUSIONS

Patients who underwent multilevel LLIF with adjunctive posterior surgery had significant clinical and radiographic improvements. Complication rates were similar compared to literature on single-level LLIF. LLIF is a viable treatment for multilevel degenerative scoliosis.

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.

The Use of Bone Morphogenetic Protein in the Intervertebral Disk Space in Minimally Invasive Transforaminal Lumbar Interbody Fusion: 10-year Experience in 688 Patients

STUDY DESIGN

Retrospective Cohort.

OBJECTIVE

The objective of this study was to characterize one surgeon's experience over a 10-year period using rhBMP-2 in the disk space for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

SUMMARY OF BACKGROUND DATA

MIS TLIF has been utilized as a technique for decreasing patients' immediate postoperative pain, decreasing blood loss, and shortened hospital stays. Effectiveness and complications of rhBMP-2's use in the disk space is limited because of its off-label status.

METHODS

Retrospective analysis of consecutive MIS TLIFs performed by senior author between 2004 and 2014. rhBMP-2 was used in the disk space in all cases. Patients were stratified based on the dose of rhBMP-2 utilized. Patients had 9 to 12 month computerized tomography scan to evaluate for bony fusion and continued follow-up for 18 months.

RESULTS

A total of 688 patients underwent a MIS TLIF. A medium kit of rhBMP-2 was utilized in 97 patients, and small kit was used in 591 patients. Fusion rate was 97.9% and this was not different between the 2 groups with 96/97 patients fusing in the medium kit group and 577/591 patients fusing in the small kit group. Five patients taken back to the operating room for symptomatic pseudoarthrosis, 4 reoperated for bony hyperostosis, and 10 radiographic pseudoarthroses that did not require reoperation. A statistically significant difference in the rate of foraminal hyperostosis was found when using a medium sized kit of rhBMP-2 was 4.12% (4/97 patients), compared with a small kit (0/591 patients, P=0.0004).

CONCLUSIONS

Utilization of rhBMP-2 in an MIS TLIF leads to high fusion rate (97.9%), with an acceptable complication profile. The development of foraminal hyperostosis is a rare complication that only affected 0.6% of patients, and seems to be a dose related complication, as this complication was eliminated when a lower dose of rhBMP-2 was utilized.

LEVEL OF EVIDENCE

Level IV.

Protecting Surgeons' Fingers from Radiation Exposure during Lumbosacral Selective Nerve Root Block

Introduction

Fluoroscopy-guided selective nerve root block (SNRB) is useful for the diagnosis and treatment of nerve root pain. However, the procedure exposes the surgeon's hands to radiation. Therefore, the purpose of this randomized prospective study was to assess the radiation exposure per unit time of the surgeon's fingers during performance of a lumbosacral SNRB and to calculate the annual exposure time limits for four hand-protection methods.

Methods

We prospectively recruited patients scheduled for an SNRB and measured the radiation exposure using a ring-type passive radiation dosimetry device attached to the distal phalanx of the index finger of the hand performing the needle placement. Patients were randomly divided into the following four groups: a) the direct exposure group, b) the 0.03-mmPb glove group, c) the 0.25-mmPb glove group, and d) the forceps group (in which the needle was held using forceps such that the fingers did not enter the irradiation field).

Results

We recruited 40 consecutive patients (16 men and 24 women), with a mean age of 69 years. In all cases, SNRB was successfully performed without complications. The average exposure per hour for each of the four groups was as follows: 0.67 ± 0.56 mSv/s in the direct exposure group, 0.12 ± 0.07 mSv/s in the 0.03-mmPb glove group, 0.019 ± 0.02 mSv/s in the 0.25-mmPb glove group, and 0.001 ± 0.004 mSv/s in the forceps group (p < 0.01). The average annual exposure time limit was 12.4 min in the direct exposure group, 67.9 min in the 0.03-mmPb glove group, 7.5 h in the 0.25-mmPb glove group, and 5.0 days in the forceps group.

Conclusions

Using a radiation reduction glove or forceps greatly decreased the radiation exposure and increased the annual exposure time limit for SNRB.

A randomized controlled trial with ≥5 years of follow-up comparing minimally invasive and open transforaminal lumbar interbody fusion in disc herniation at single level

Minimally invasive transforaminal lumbar interbody fusion (m-TLIF) using transpedicular screws has various advantages over classical open (c-) TLIF. Up to date, comparative analyses of the TLIF procedures were following patients for <5 years. The objective of the present study was to compare the clinical effectiveness and complications of m- and c-TLIF in patients with single-level disc herniation with ≥5 years follow-up. Between June 2008 to July 2010, 91 patients with single-level lumbar degeneration were recruited and were randomly divided into two groups: m-TLIF and c-TLIF. The analyzed outcome measurements included: Surgery duration, intraoperative blood loss, X-ray exposure time, T2 relaxation time in magnetic resonance imaging (MRI), visual analogue scale (VAS) scores, Japanese orthopedic association (JOA) scores, fusion rate and complications during follow-up. No significant differences between m- and c-TLIF were observed with respect to surgery duration (P=0.077), volume of blood loss (P=0.115), complications and the need for an additional surgery (P=0.632). Significant differences between the groups were observed for X-ray exposure time (P<0.001) and MRI T2 relaxation times at 3 months post-surgery (P<0.001). At day 7 post surgery, recorded VAS and JOA scores were significantly improved in the m-TLIF compared with the c-TLIF group and non-significant differences between the groups were observed at >1 month follow-up. m-TLIF was a safe and effective tool in treating single-level lumbar disc herniation. However, careful attention to the surgical technique and precise anatomical knowledge were required. Further studies and refinement of the surgical techniques are necessary prior to treating multiple or more extensive lesions using the m-TLIF method.

Utilization of Spinal Intra-operative Three-dimensional Navigation by Canadian Surgeons and Trainees: A Population-based Time Trend Study

Background

Computer-assisted navigation (CAN) improves the accuracy of spinal instrumentation in vertebral fractures and degenerative spine disease; however, it is not widely adopted because of lack of training, high capital costs, workflow hindrances, and accuracy concerns. We characterize shifts in the use of spinal CAN over time and across disciplines in a single-payer health system, and assess the impact of intra-operative CAN on trainee proficiency across Canada.

Methods

A prospectively maintained Ontario database of patients undergoing spinal instrumentation from 2005 to 2014 was reviewed retrospectively. Data were collected on treated pathology, spine region, surgical approach, institution type, and surgeon specialty. Trainee proficiency with CAN was assessed using an electronic questionnaire distributed across 15 Canadian orthopedic surgical and neurosurgical programs.

Results

In our provincial cohort, 16.8% of instrumented fusions were CAN-guided. Navigation was used more frequently in academic institutions (15.9% vs. 12.3%, p<0.001) and by neurosurgeons than orthopedic surgeons (21.0% vs. 12.4%, p<0.001). Of residents and fellows 34.1% were fully comfortable using spinal CAN, greater for neurosurgical than orthopedic surgical trainees (48.1% vs. 11.8%, p=0.008). The use of CAN increased self-reported proficiency in thoracic instrumentation for all trainees by 11.0% (p=0.036), and in atlantoaxial instrumentation for orthopedic trainees by 18.0% (p=0.014).

Conclusions

Spinal CAN is used most frequently by neurosurgeons and in academic centers. Most spine surgical trainees are not fully comfortable with the use of CAN, but report an increase in technical comfort with CAN guidance particularly for thoracic instrumentation. Increased education in spinal CAN for trainees, particularly at the fellowship stage and, specifically, for orthopedic surgery, may improve adoption.

Evidence Based Medicine Review of Posterior Thoracolumbar Minimally Invasive Technology

Background

Evaluate the current evidence in meta-analyses on posterior thoracolumbar minimally invasive surgery techniques and outcomes for degenerative conditions.

Methods

A systematic review of the literature from 1950 to 2015.

Results

The review of the literature yielded 34 meta-analysis studies evaluating posterior thoracolumbar minimally invasive techniques and outcomes for degenerative conditions. There were 11 studies included which investigated minimally invasive surgery (MIS) versus open posterior lumbar decompressions. There were 14 studies included which investigated MIS versus open posterior lumbar interbody fusions. Finally, there were 9 studies focused on navigation techniques and radiation safety within MIS procedures.

Conclusions

There are 34 meta-analysis studies evaluating minimally invasive to open thoracolumbar surgery for degenerative disease. The studies show a trend toward decreased estimated blood loss, decreased length of stay, decreased complications, similar fusion rates, improved accuracy, and decreased radiation when minimally invasive techniques are used.

Radiation Exposure to the Surgeons and Patients in Fluoroscopic-Guided Segmental Pedicle Screw Placement for Pediatric Scoliosis

STUDY DESIGN

Prospective case series.

OBJECTIVE

To analyze the radiation exposure to the surgeons and patients in fluoroscopic-guided segmental pedicle screw placement for pediatric scoliosis.

SUMMARY OF BACKGROUND DATA

Fluoroscopic-guided pedicle screw placement is a safer technique for pedicle screw placement in spinal deformity. However, radiation exposure is a concern, particularly for spine surgeons due to the requirement of multiple pedicle screws in spinal deformity surgery.

METHODS

We measured radiation dose to the surgeons and pediatric patients undergoing scoliosis surgery by a team of two surgeons (S1 and S2) from March 2016 to December 2017. Surgery was performed using fluoroscopic-guided segmental pedicle screw placement. The dosimeters were placed at the forehead, inside and outside thyroid shield, both hands, back, and suprapubic under lead apron for each surgeon; and at the thyroid and gonads for patients.

RESULTS

Thirty patients were included in the study. The mean numbers of pedicle screws per case were 23.2 ± 3.4. The mean dose (mrem) per case for the two surgeons S1 and S2 was 0.07 and 0.47 at forehead, 0.07 and 0.37 at outside thyroid shield, 0.00 and 0.30 at inside thyroid shield, 16.87 and 13.73 at right hand, 6.07 and 11.37 at left hand, 0.50 and 0.00 at back, and 0.00 and 0.00 at suprapubic under lead apron, respectively. The mean dose (mrem) per case for the male and female patient was 3.67 and 14.71 for thyroid and 3.83 and 3.17 for gonads, respectively.

CONCLUSION

The results of this study demonstrated that radiation exposure to the spine surgeons and patients is low using fluoroscopic-guided segmental pedicle screw technique for pediatric scoliosis surgery. Both hands of the surgeons received much higher doses compared to other body areas and, and thus radiation-reducing gloves and careful attention to surgeon's hands need to be considered for this procedure.

LEVEL OF EVIDENCE

2.

Effectiveness of using low rate fluoroscopy to reduce an examiner's radiation dose during lumbar nerve root block

BACKGROUND

Long-term exposure to radiation can lead to gene mutations and increase the risk of cancer. Low rate fluoroscopy has the potential to reduce the radiation exposure for both the examiner and the patient during various fluoroscopic procedures. The purpose of this study was to evaluate the impact of low rate fluoroscopy on reducing an examiner's radiation dose during nerve root block.

METHODS

A total of 101 lumbar nerve root block examinations were performed at our institute during a 6-month period. During the first 3 months, low rate fluoroscopy was performed at 7.5 frames/s (FPS) in 54 examinations, while 47 were performed at 15 FPS during the last 3 months. The examiner wore a torso protector, a neck protector, radiation protection gloves, and radiation protection glasses. Optically stimulated luminescence (OSL) dosimeter badges were placed on both the inside and the outside of each protector. The dosimeters were exchanged every month. Radiation doses (mSv) were measured as the integrated radiation quantity every month from the OSL dosimeters. The effective and equivalent doses for the hands, skin, and eyes were investigated.

RESULTS

The mean monthly equivalent doses were significantly lower both inside and outside the hand protector for the 7.5 FPS versus 15 FPS (inside; P = 0.021, outside; P = 0.024). There were no significant differences between the two groups for the mean monthly calculated effective dose for each protector's condition.

CONCLUSIONS

Radiation exposure was significantly reduced for the skin on the examiner's hand when using low rate fluoroscopy at 7.5 FPS, with no noticeable decrease in image quality or prolonged fluoroscopy time.

Surgeon's and patient's radiation exposure during percutaneous thoraco-lumbar pedicle screw fixation: A prospective multicenter study of 100 cases

HYPOTHESIS

Percutaneous pedicle screw fixations (PPSF) are increasingly used in spine surgery, minimizing morbidity through less muscle breakdown but at the cost of intraoperative fluoroscopic guidance that generates high radiation exposure. Few studies have been conducted to measure them accurately.

MATERIAL AND METHODS

The objective of our study is to quantify, during a PPSF carried out in different experimented centers respecting current radiation protection recommendations, this irradiation at the level of the surgeon and the patient. We have prospectively included 100 FPVP procedures for which we have collected radiation doses from the main operator. For each procedure, the doses of whole-body radiation, lens and extremities were measured.

RESULTS

Our results show a mean whole body, extremity and lens exposure dose per procedure reaching 1.7±2.8μSv, 204.7±260.9μSv and 30.5±25.9μSv, respectively. According to these values, the exposure of the surgeon's extremities and lens will exceed the annual limit allowed by the International Commission on Radiological Protection (ICRP) after 2440 and 4840 procedures respectively.

CONCLUSION

Recent European guidelines will reduce the maximum annual exposure dose from 150 to 20mSv. The number of surgical procedures to not reach the eye threshold, according to our results, should not exceed 645 procedures per year. Pending the democratization of neuronavigation systems, the use of conventional fluoroscopy exposes the eyes in the first place. Therefore they must be protected by leaded glasses.

LEVEL OF PROOF

IV, case series.

Percutaneous pedicle screw placement under single dimensional fluoroscopy with a designed pedicle finder-a technical note and case series

BACKGROUND CONTEXT

Minimally invasive spine surgery has become increasingly popular in clinical practice, and it offers patients the potential benefits of reduced blood loss, wound pain, and infection risk, and it also diminishes the loss of working time and length of hospital stay. However, surgeons require more intraoperative fluoroscopy and ionizing radiation exposure during minimally invasive spine surgery for localization, especially for guidance in instrumentation placement. In addition, computer navigation is not accessible in some facility-limited institutions.

PURPOSE

This study aimed to demonstrate a method for percutaneous screws placement using only the anterior-posterior (AP) trajectory of intraoperative fluoroscopy.

STUDY DESIGN

A technical report (a retrospective and prospective case series) was carried out.

PATIENT SAMPLE

Patients who received posterior fixation with percutaneous pedicle screws for thoracolumbar degenerative disease or trauma comprised the patient sample.

METHOD

We retrospectively reviewed the charts of consecutive 670 patients who received 4,072 pedicle screws between December 2010 and August 2015. Another case series study was conducted prospectively in three additional hospitals, and 88 consecutive patients with 413 pedicle screws were enrolled from February 2014 to July 2016. The fluoroscopy shot number and radiation dose were recorded. In the prospective study, 78 patients with 371 screws received computed tomography at 3 months postoperatively to evaluate the fusion condition and screw positions.

RESULTS

In the retrospective series, the placement of a percutaneous screw required 5.1 shots (2-14, standard deviation [SD]=2.366) of AP fluoroscopy. One screw was revised because of a medialwall breach of the pedicle. In the prospective series, 5.8 shots (2-16, SD=2.669) were required forone percutaneous pedicle screw placement. There were two screws with a Grade 1 breach (8.6%), both at the lateral wall of the pedicle, out of 23 screws placed at the thoracic spine at T9-T12. Forthe lumbar and sacral areas, there were 15 Grade 1 breaches (4.3%), 1 Grade 2 breach (0.3%), and 1 Grade 3 breach (0.3%). No revision surgery was necessary.

CONCLUSION

This method avoids lateral shots of fluoroscopy during screw placement and thus decreases the operation time and exposes surgeons to less radiation. At the same time, compared with the computer-navigated procedure, it is less facility-demanding, and provides satisfactory reliability and accuracy.

Radiation reduction of minimally invasive transforaminal lumbar interbody fusion with localisation system in overweight patients: practical technique

AIMS

Minimally invasive transforaminal lumbar interbody fusion (MITLIF) has been well validated in overweight and obese patients who are consequently subject to a higher radiation exposure. This prospective multicentre study aimed to investigate the efficacy of a novel lumbar localisation system for MITLIF in overweight patients.

PATIENTS AND METHODS

The initial study group consisted of 175 patients. After excluding 49 patients for various reasons, 126 patients were divided into two groups. Those in Group A were treated using the localisation system while those in Group B were treated by conventional means. The primary outcomes were the effective radiation dosage to the surgeon and the exposure time.

RESULTS

There were 62 patients in Group A and 64 in Group B. The mean effective dosage was 0.0217 mSv (standard deviation (sd) 0.0079) in Group A and 0.0383 mSv (sd 0.0104) in Group B (p < 0.001). The mean fluoroscopy exposure time was 26.42 seconds (sd 5.91) in Group A and 40.67 seconds (sd 8.18) in Group B (p < 0.001). The operating time was 175.56 minutes (sd 32.23) and 206.08 minutes (sd 30.15) (p < 0.001), respectively. The mean pre-operative localisation time was 4.73 minutes (sd 0.84) in Group A and 7.03 minutes (sd 1.51) in Group B (p < 0.001). The mean screw placement time was 47.37 minutes (sd 10.43) in Group A and 67.86 minutes (sd 14.15) in Group B (p < 0.001). The pedicle screw violation rate was 0.35% (one out of 283) in Group A and 2.79% (eight out of 287) in Group B (p = 0.020).

CONCLUSION

The study shows that the localisation system can effectively reduce radiation exposure, exposure time, operating time, pre-operative localisation time, and screw placement time in overweight patients undergoing MITLIF. Cite this article: Bone Joint J 2017;99-B:944-50.

Effects of Preoperative Simulation on Minimally Invasive Hybrid Lumbar Interbody Fusion

OBJECTIVE

The main focus of this study was to evaluate how preoperative simulation affects the surgical work flow, radiation exposure, and outcome of minimally invasive hybrid lumbar interbody fusion (MIS-HLIF).

METHODS

A total of 132 patients who underwent single-level MIS-HLIF were enrolled in a cohort study design. Dose area product was analyzed in addition to surgical data. Once preoperative simulation was established, 66 cases (SIM cohort) were compared with 66 patients who had previously undergone MIS-HLIF without preoperative simulation (NO-SIM cohort).

RESULTS

Dose area product was reduced considerably in the SIM cohort (320 cGy·cm² NO-SIM cohort: 470 cGy·cm²; P < 0.01). Surgical time was shorter for the SIM cohort (155 minutes; NO-SIM cohort, 182 minutes; P < 0.05). SIM cohort had a better outcome in Numeric Rating Scale back at 6 months follow-up compared with the NO-SIM cohort (P < 0.05).

CONCLUSIONS

Preoperative simulation reduced radiation exposure and resulted in less back pain at the 6 months follow-up time point. Preoperative simulation provided guidance in determining the correct cage height. Outcome controls enabled the surgeon to improve the procedure and the software algorithm.

Radiation Exposure to the Surgeon During Ultrasound-Assisted Transforaminal Percutaneous Endoscopic Lumbar Discectomy: A Prospective Study

OBJECTIVE

To determine the radiation dose to the surgeon during ultrasound-assisted transforaminal percutaneous endoscopic lumbar discectomy (PELD) for lumbar disc herniation, and to investigate whether the usage of ultrasonography could reduce the radiation exposure to the surgeon.

METHODS

The stages of needle insertion and foraminal plasty for transforaminal PELD were performed under ultrasound guidance and confirmed by fluoroscopy according to the standard technique by 2 spinal surgeons separately in 25 transforaminal PELDs (25 levels). The radiation exposure dose of the surgeons' chest above and below the shielding and the fluoroscopy time were recorded. The effective dose and number of possible levels per year within the yearly occupational exposure limit (OEL) were calculated. The radiation dose per level and fluoroscopy time between ultrasound-assisted PELD and fluoroscopy-assisted PELD were compared.

RESULTS

The mean operation time and fluoroscopy time were 67.6 ± 14.6 minutes and 2.9 ± 0.7 seconds, respectively. The mean effective dose to the surgeons per level was 1.3 ± 0.6 μSv. One surgeon could perform PELDs at 38,462 levels per year without exceeding the OEL for whole-body radiation wearing a lead apron, and 1938 levels per year without using any shielding devices. Ultrasound-assisted PELD had significantly less radiation dose per level at the chest below and above apron, effective dose per level, and fluoroscopy time, compared with fluoroscopy-assisted PELD (all P < 0.05).

CONCLUSIONS

The method of ultrasound-assisted needle insertion and foraminal plasty in transforaminal PELD can reduce radiation exposure to the surgeons compared with fluoroscopy-assisted PELD.

Exposure of the examiner to radiation during myelography versus radiculography and root block: A comparative study

BACKGROUND

Exposure to radiation over many years prompts concerns regarding potential health-related effects, particularly the incidence of cataracts and the development of cancer. The purpose of this study was to examine and compare the exposure of the examiner to radiation during myelography versus radiculography and root block.

METHODS

A total of 114 examinations were performed in our institute in the 6 months. Sixty-two examinations were performed during myelography in the first 3 months (MG group), while 52 were performed during radiculography and root block in the last 3 months (RB group). The examiner wore a torso protector, a neck protector, radiation protection gloves, and radiation protection glasses. Optically stimulated luminescence (OSL) dosimeter badges were placed on both the inside and the outside of each protector. The dosimeters were exchanged every month. Radiation doses (mSv) were measured as the integrated radiation quantity every month from the OSL dosimeters. The effective dose and the equivalent doses of hand, skin, and eyes were investigated.

RESULTS

The mean equivalent doses were significantly lower outside the neck, torso, eye protectors, and inside the torso protector in the RB group than in the MG group. Conversely, the mean equivalent dose was significantly lower outside the hand protector in the MG group than in the RB group. The use of a neck protector significantly decreased the effective dose compared to the non-use of a neck protector in the RB group.

CONCLUSIONS

The present study showed the standard radiation exposure to the examiner during myelography, radiculography, and root block. Receiving full protection including a neck protector and protection gloves is an easy and reliable means to reduce radiation exposure.

Modified Mini-open Transforaminal Lumbar Interbody Fusion: Description of Surgical Technique and Assessment of Free-hand Pedicle Screw Insertion

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To describe a modified technique for mini-open transforaminal lumbar interbody fusion (TLIF) that improves visualization for decompression, fusion, and freehand pedicle screw insertion. Accuracy of freehand pedicle screw placement with this technique was assessed.

SUMMARY OF BACKGROUND DATA

Mini-open TLIF is a minimally invasive technique that allows limited visualization of the bone and neural anatomy via an expandable tubular retractor inserted through the Wiltse plane. No significant modification that of this technique has been described in detail.

METHODS

In this study, 92 consecutive patients underwent one-level modified mini-open TLIF (MOTLIF). MOTLIF modifications consisted of (i) transmuscular dissection through the multifidus muscle rather than intermuscular dissection in the Wiltse plane; (ii) microsurgical detachment of multifidus from the facet rather than muscle dilation; (iii) en bloc total facetectomy (unilateral or bilateral, as needed for decompression); (iv) facet autograft used for interbody fusion; and (v) solid pedicle screws placed bilaterally by a freehand technique under direct vision.

RESULTS

The mean age was 53 years. Mean follow-up was 35 months (minimum 2 yrs). By 6 months, mean Visual Analog Scale for back and leg pain had improved from 51 to 19 and from 58 to 17, respectively, and mean Oswestry Disability Index (ODI) improved from 53 to 16. These improvements persisted at 2 years. Solid fusion, defined by computed tomography at 1 year, was achieved in 88.1%, whereas satisfactory fusion was achieved in 95.2% of patients. Pedicle screws were accurately placed in 335 of 336 imaged pedicles (pedicle breach grades: 91.1% grade 1; 8.6% grade 2; and 0.3% grade 3). Mean fluoroscopy time was 29.3 seconds.

CONCLUSION

MOTLIF is a safe and effective minimally invasive technique with a high fusion rate. It allows accurate pedicle screw placement by a freehand technique. By eliminating bi-planar fluoroscopy, it helps reduce radiation exposure. This is the largest published report of mini-open TLIF to date.

LEVEL OF EVIDENCE

4.

True anteroposterior view pedicle screw insertion technique

BACKGROUND

The wide use of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery in the treatment of degenerative disc disease of lumbar spine in spinal surgery highlights the gradual decrease in the use of traditional pedicle screw insertion technology. This study aims to analyze the accuracy of the true anteroposterior view pedicle screw insertion technique in MIS-TLIF surgery, compare it with conventional pedicle screw insertion technology, and discuss its clinical application value.

METHODS

Fifty-two patients undergoing true anteroposterior view (group A) and 87 patients undergoing conventional pedicle screw insertion (group B) were diagnosed with lumbar disc herniation or lumbar spinal stenosis. Time for screw placement, intraoperative irradiation exposure, accuracy rate of pedicle screw insertion, and incidence of neurovascular injury were compared between the two groups.

RESULTS

The time for screw placement and intraoperative irradiation exposure was significantly less in group A. Penetration rates of the paries lateralis of vertebral pedicle, medial wall of vertebral pedicle, and anterior vertebral wall were 1.44%, 0%, and 2.40%, respectively, all of which were significantly lower than that in group B. No additional serious complications caused by the placement of screw were observed during the follow-up period in patients in group A, but two patients with medial penetration underwent revision for unbearable radicular pain.

CONCLUSION

The application of true anteroposterior view pedicle screw insertion technique in MIS-TLIF surgery shortens time for screw placement and reduces the intraoperative irradiation exposure along with a higher accuracy rate of screw placement, which makes it a safe, accurate, and efficient technique.

MASTERS-D Study: A Prospective, Multicenter, Pragmatic, Observational, Data-Monitored Trial of Minimally Invasive Fusion to Treat Degenerative Lumbar Disorders, One-Year Follow-Up

The objective of the study is to assess effectiveness and safety of minimally invasive lumbar interbody fusion (MILIF) for degenerative lumbar disorders (DLD) in daily surgical practice and follow up with patients for one year after surgery.

A prospective, multicenter, pragmatic, monitored, international outcome study in patients with DLD causing back/leg pain was conducted (19 centers). Two hundred fifty-two patients received standard of care available in the centers. Patients were included if they were aged >18 years, required one- or two-level lumbar fusion for DLD, and met the criteria for approved device indications. Primary endpoints: time to first ambulation (TFA) and time to surgery recovery (TSR). Secondary endpoints: patient-reported outcomes (PROs)--back and leg pain (visual analog scale), disability (Oswestry Disability Index (ODI)), health status (EQ-5D), fusion rates, reoperation rates, change in pain medication, rehabilitation, return to work, patient satisfaction, and adverse events (AEs). Experienced surgeons (≥30 surgeries pre-study) treated patients with DLD by one- or two-level MILIF and patients were evaluated for one year (NCT01143324).

At one year, 92% (233/252) of patients remained in the study. Primary outcomes: TFA, 1.3 ±0.5 days and TSR, 3.2 ±2.0 days. Secondary outcomes: Most patients (83.3%) received one level MILIF; one (two-level) MILIF mean surgery duration, 128 (182) min; fluoroscopy time, 115 (154) sec; blood loss, 164 (233) mL; at one year statistically significant (P<.0001) and clinically meaningful changes from baseline were reported in all PROs--reduced back pain (2.9 ±2.5 vs. 6.2 ±2.3 at intake), reduced leg pain (2.2 ±2.6 vs. 5.9 ±2.8), and ODI (22.4% ± 18.6 vs. 45.3% ± 15.3), as well as health-related quality of life (EQ-5D index: 0.71 ±0.28 vs. 0.34 ±0.32). More of the professional workers were working at one year than those prior to surgery (70.3% vs. 55.2%). Three AEs and one serious AE were considered procedure-related; there were no deep site infections or deaths.

This is the first study evaluating MILIF for treatment of DLD in daily clinical practice. Clinically significant improvements were observed in all endpoints. Short-term post-surgery improvements (four weeks) were maintained through one year with minimal complications. Our results suggest that MILIF has good-to-excellent outcomes for the treatment of DLD in a broad patient population under different clinical conditions and healthcare delivery systems.

Radiation Exposure of Interventional Radiologists During Computed Tomography Fluoroscopy-Guided Renal Cryoablation and Lung Radiofrequency Ablation: Direct Measurement in a Clinical Setting

INTRODUCTION

Computed tomography (CT) fluoroscopy-guided renal cryoablation and lung radiofrequency ablation (RFA) have received increasing attention as promising cancer therapies. Although radiation exposure of interventional radiologists during these procedures is an important concern, data on operator exposure are lacking.

MATERIALS AND METHODS

Radiation dose to interventional radiologists during CT fluoroscopy-guided renal cryoablation (n = 20) and lung RFA (n = 20) was measured prospectively in a clinical setting. Effective dose to the operator was calculated from the 1-cm dose equivalent measured on the neck outside the lead apron, and on the left chest inside the lead apron, using electronic dosimeters. Equivalent dose to the operator's finger skin was measured using thermoluminescent dosimeter rings.

RESULTS

The mean (median) effective dose to the operator per procedure was 6.05 (4.52) μSv during renal cryoablation and 0.74 (0.55) μSv during lung RFA. The mean (median) equivalent dose to the operator's finger skin per procedure was 2.1 (2.1) mSv during renal cryoablation, and 0.3 (0.3) mSv during lung RFA.

CONCLUSION

Radiation dose to interventional radiologists during renal cryoablation and lung RFA were at an acceptable level, and in line with recommended dose limits for occupational radiation exposure.

Peri-operative radiation exposure: Are overweight patients at increased risks?

The aim of this study was to identify if there was a correlation between body mass index (BMI) and intra-operative radiation exposure. A retrospective review of 81 patients who had sliding hip screw fixation for femoral neck fractures in one year was completed, recording body mass index (BMI), screening time, dose area product (DAP), American Society of Anesthesiologists (ASA) grade, seniority of operating surgeon and complexity of the fracture configuration. There was a statistically significant correlation between dose area product and BMI. There was no statistically significant relationship between screening time and BMI. There was no statistical difference between ASA grade, seniority of surgeon, or complexity of fracture configuration and dose area product. Simulated stochastic risks were increased for overweight patients. Overweight patients are exposed to increased doses of radiation regardless of length of screening time. Surgeons and theatre staff should be aware of the increased radiation exposure during fixation of fractures in overweight patients and, along with radiographers, ensure steps are taken to minimise these risks. Whilst such radiation dosages may have little adverse effect for individual patients, these findings may be of more relevance and concern to staff that will be exposed to increased radiation.