Cost-effectiveness of image-guided spine surgery

Higher Accuracy and Better Clinical Outcomes in Navigated Thoraco-Lumbar Pedicle Screw Fixation Versus Conventional Techniques : A Systematic Review and Meta-Analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

This study aims to compare pedicle screw accuracy, clinical outcomes, and complications between navigated and conventional techniques.

SUMMARY OF BACKGROUND DATA

In the last decades, intraoperative navigation has been introduced in spinal surgery to prevent risks and complications.

MATERIALS AND METHODS

The search was executed on Cochrane Central Library, PubMed, and Scopus on April 30, 2023. Randomized controlled trials, prospective and retrospective studies that compared pedicle screw accuracy in the thoracic-lumbar-sacral segments, blood loss, operative time, hospital stay, intraoperative and postoperative revision of screws, neurological and systemic complications, Visual Analogue Scale (VAS), and Oswestry Disability Index (ODI) between navigated and freehand or fluoroscopy-assisted techniques were included in this study. The meta-analysis was performed using Review Manager software. Clinical outcomes were assessed as continuous outcomes with mean difference, while pedicle screw accuracy and complications were assessed as dichotomous outcomes with odds ratio, all with 95% CIs. The statistical significance of the results was fixed at P <0.05.

RESULTS

This meta-analysis included 30 studies for a total of 17,911 patients and 24,600 pedicle screws. Statistically significant results in favor of the navigated technique were observed for the accuracy of pedicle screws ( P =0.0001), hospital stay ( P =0.0002), blood loss ( P <0.0001), postoperative revision of pedicle screws ( P <0.00001), and systemic complications ( P =0.0008). In particular, the positioning of the screws was clinically acceptable in 96.2% of the navigated group and 94.2% with traditional techniques. No significant differences were found in VAS, ODI, and operative time between the two groups.

CONCLUSION

Navigated pedicle screw fixation has been demonstrated to be a safe and effective technique with high improvement in clinical outcomes and accuracy in patients undergoing spinal fusion compared with conventional techniques.

LEVEL OF EVIDENCE

Level III.

What is the Marginal Cost of Using Robot Assistance or Navigation for Transforaminal Lumbar Interbody Fusion? A Time-Driven Activity-Based Cost Analysis

BACKGROUND AND OBJECTIVE

Our primary objective was to compare the marginal intraoperative cost of 3 different methods for pedicle screw placement as part of transforaminal lumbar interbody fusions (TLIFs). Specifically, we used time-driven activity-based costing to compare costs between robot-assisted TLIF (RA-TLIF), TLIF with intraoperative navigation (ION-TLIF), and freehand (non-navigated, nonrobotic) TLIF.

METHODS

Total cost was divided into direct and indirect costs. We identified all instances of RA-TLIF (n = 20), ION-TLIF (n = 59), and freehand TLIF (n = 233) from 2020 to 2022 at our institution. Software was developed to automate the extraction of all intraoperatively used personnel and material resources from the electronic medical record. Total costs were determined through a combination of direct observation, electronic medical record extraction, and interdepartmental collaboration (business operations, sterile processing, pharmacy, and plant operation departments). Multivariable linear regression analysis was performed to compare costs between TLIF modalities, accounting for patient-specific factors as well as number of levels fused, surgeon, and hospital site.

RESULTS

The average total intraoperative cost per case for the RA-TLIF, ION-TLIF, and freehand TLIF cohorts was $24 838 ± $10 748, $15 991 ± $6254, and $14 498 ± $6580, respectively. Regression analysis revealed that RA-TLIF had significantly higher intraoperative cost compared with both ION-TLIF (β-coefficient: $7383 ± $1575, P < .001) and freehand TLIF (β-coefficient: $8182 ± $1523, P < .001). These cost differences were primarily driven by supply cost. However, there were no significant differences in intraoperative cost between ION-TLIF and freehand TLIF ( P = .32).

CONCLUSION

We demonstrate a novel use of time-driven activity-based costing methodology to compare different modalities for executing the same type of lumbar fusion procedure. RA-TLIF entails significantly higher supply cost when compared with other modalities, which explains its association with higher total intraoperative cost. The use of ION, however, does not add extra expense compared with freehand TLIF when accounting for confounders. This might have implications as surgeons and hospitals move toward bundled payments.

Navigation and Robotic Single-Position Prone LLIF: First Cases in Brazil

OBJECTIVE

has been rapid technological advancement in navigation-guided minimally invasive surgery over the past two decades, making these advancements an invaluable aid for surgeons by essentially providing real-time virtual reconstruction of patient anatomy. The objectives of these navigation- and robot-guided procedures are to reduce the likelihood of neural and vascular injury, minimize hospitalization time, decrease bleeding and postoperative pain, shorten healing time, and lower infection rates.

METHODS

A unicentric, retrospective cohort study was conducted to evaluate the preoperative and postoperative clinical and radiographic outcomes of the first Latin American patients diagnosed with lumbar degenerative disease who underwent lumbar interbody fusion at the L4-L5 level via prone-position lateral lumbar interbody fusion-single position prone access.

RESULTS

A total of 80 patients (40 assisted by fluoroscopy, 40 assisted by robotics) with 320 percutaneous pedicle screws were evaluated. The primary outcomes analyzed and compared were radiation exposure per screw (seconds), skin-to-skin operative time (minutes), and recovery time (days). Secondary outcomes included lumbar pain intensity (visual analog scale), reported functional disability (Oswestry Disability Index), and any potential complications. All secondary outcomes were collected at the postoperative time.

CONCLUSION

Comparing minimally invasive spine interventions with free-hand instrumentation and robotic instrumentation, a statistically significant difference was identified in radiation exposure per screw and surgical time. The literature on Cirq Robotic is limited; however, minimally invasive spine surgery with robotic assistance appears advantageous in terms of radiation exposure and surgical time.

Feasibility of a novel augmented reality overlay for cervical screw placement in phantom spine models

STUDY DESIGN

Feasibility study.

PURPOSE

A phantom model was used to evaluate the accuracy of a novel augmented reality (AR) system for cervical screw placement.

OVERVIEW OF LITERATURE

The use of navigation systems is becoming increasingly common in spine procedures. However, numerous factors limit the feasibility of regular and widespread use of navigation tools during spine surgery. AR is a new technology that has already demonstrated utility as a navigation tool during spine surgery. However, advancements in AR technology are needed to increase its adoption by the medical community.

METHODS

AR technology that uses a fiducial-less registration system was tested in a preclinical cervical spine phantom model study for accuracy during spinal screw placement. A three-dimensional reconstruction of the spine along with trajectory lines was superimposed onto the phantom model using an AR headset. Participants used the AR system to guide screw placement, and post-instrumentation scans were compared for accuracy assessment.

RESULTS

Twelve cervical screws were placed under AR guidance. All screws were placed in an acceptable anatomic position. The average distance error for the insertion point was 2.73±0.55 mm, whereas that for the endpoint was 2.71±0.69 mm. The average trajectory angle error for all insertions was 2.69°±0.59°.

CONCLUSIONS

This feasibility study describes a novel registration approach that superimposes spinal anatomy and trajectories onto the surgeon's real-world view of the spine. These results demonstrate reasonable accuracy in the preclinical model. The results of this study demonstrate that this technology can assist with accurate screw placement. Further investigation using cadaveric and clinical models is warranted.

Risk Factors of Screw Malposition in Robot-Assisted Cortical Bone Trajectory: Analysis of 1344 Consecutive Screws in 256 Patients

STUDY DESIGN

Retrospective single-center study using prospectively collected data.

OBJECTIVE

To describe the incidence of and identify risk factors for intraoperative screw malposition secondary to skive or shift during robot-assisted cortical bone trajectory (RA-CBT) insertion.

SUMMARY OF BACKGROUND DATA

RA-CBT screw malposition occurs through 2 distinct modes, skive or shift. Skive occurs when a downward force applied to the cannula, drill, tap, or screw, causes the instrument to deflect relative to its bony landmark. Shift is a change in the position of the RA system relative to the patient after registration.

PATIENTS AND METHODS

A consecutive series of patients older than 18 years who underwent RA-CBT screw placement between January 2019 and July 2022 were enrolled. Baseline demographic and surgical data, Hounsfield Units (HUs) at L1, and vertebral shape related to screw planning were collected. Skive or shift was recorded in the operating room on a data collection form.

RESULTS

Of 1344 CBT screws in 256 patients, malposition was recognized intraoperatively in 33 screws (2.4%) in 27 patients (10.5%); 19 through skive in 17 and 14 through shift in 10 patients. These patients had higher body mass index than patients without malposition (33.0 vs. 30.5 kg/m 2 , P = 0.037). Patients with skive had higher HU (178.2 vs . 145.2, P = 0.035), compared with patients with shift (139.2 vs . 145.2, P = 0.935) and patients without screw malposition. More than half of the screw malposition was observed at the upper instrumented vertebra. At the upper instrumented vertebra, if the screw's overlap to the bone surface at the insertion point was decreased, skive was more likely (57% vs . 87%, P < 0.001). No patients were returned to the operating room for screw revision.

CONCLUSIONS

Intraoperative screw malposition occurred in 2.4% of RA-CBT. High body mass index was associated with screw malposition, regardless of etiology. Skive was associated with high HU and decreased screw overlap to the bone surface at the insertion point.

Pushing the Limits of Minimally Invasive Spine Surgery-From Preoperative to Intraoperative to Postoperative Management

The introduction of minimally invasive surgery ushered in a new era of spine surgery by minimizing the undue iatrogenic injury, recovery time, and blood loss, among other complications, of traditional open procedures. Over time, technological advancements have further refined the care of the operative minimally invasive spine patient. Moreover, pre-, and postoperative care have also undergone significant change by way of artificial intelligence risk stratification, advanced imaging for surgical planning and patient selection, postoperative recovery pathways, and digital health solutions. Despite these advancements, challenges persist necessitating ongoing research and collaboration to further optimize patient care in minimally invasive spine surgery.

Navigation-Guided/Robot-Assisted Spinal Surgery: A Review Article

The development of minimally invasive spinal surgery utilizing navigation and robotics has significantly improved the feasibility, accuracy, and efficiency of this surgery. In particular, these methods provide improved accuracy of pedicle screw placement, reduced radiation exposure, and shortened learning curves for surgeons. However, research on the clinical outcomes and cost-effectiveness of navigation and robot-assisted spinal surgery is still in its infancy. Therefore, there is limited available evidence and this makes it difficult to draw definitive conclusions regarding the long-term benefits of these technologies. In this review article, we provide a summary of the current navigation and robotic spinal surgery systems. We concluded that despite the progress that has been made in recent years, and the clear advantages these methods can provide in terms of clinical outcomes and shortened learning curves, cost-effectiveness remains an issue. Therefore, future studies are required to consider training costs, variable initial expenses, maintenance and service fees, and operating costs of these advanced platforms so that they are feasible for implementation in standard clinical practice.

Advancing Prone-Transpsoas Spine Surgery: A Narrative Review and Evolution of Indications with Representative Cases

The Prone Transpsoas (PTP) approach to lumbar spine surgery, emerging as an evolution of lateral lumbar interbody fusion (LLIF), offers significant advantages over traditional methods. PTP has demonstrated increased lumbar lordosis gains compared to LLIF, owing to the natural increase in lordosis afforded by prone positioning. Additionally, the prone position offers anatomical advantages, with shifts in the psoas muscle and lumbar plexus, reducing the likelihood of postoperative femoral plexopathy and moving critical peritoneal contents away from the approach. Furthermore, operative efficiency is a notable benefit of PTP. By eliminating the need for intraoperative position changes, PTP reduces surgical time, which in turn decreases the risk of complications and operative costs. Finally, its versatility extends to various lumbar pathologies, including degeneration, adjacent segment disease, and deformities. The growing body of evidence indicates that PTP is at least as safe as traditional approaches, with a potentially better complication profile. In this narrative review, we review the historical evolution of lateral interbody fusion, culminating in the prone transpsoas approach. We also describe several adjuncts of PTP, including robotics and radiation-reduction methods. Finally, we illustrate the versatility of PTP and its uses, ranging from 'simple' degenerative cases to complex deformity surgeries.

Mixed Reality Surgical Navigation System; Positional Accuracy Based on Food and Drug Administration Standard

BACKGROUND

Computer assisted surgical navigation systems are designed to improve outcomes by providing clinicians with procedural guidance information. The use of new technologies, such as mixed reality, offers the potential for more intuitive, efficient, and accurate procedural guidance. The goal of this study is to assess the positional accuracy and consistency of a clinical mixed reality system that utilizes commercially available wireless head-mounted displays (HMDs), custom software, and localization instruments.

METHODS

Independent teams using the second-generation Microsoft HoloLens© hardware, Medivis SurgicalAR© software, and localization instruments, tested the accuracy of the combined system at different institutions, times, and locations. The ASTM F2554-18 consensus standard for computer-assisted surgical systems, as recognized by the U.S. FDA, was utilized to measure the performance. 288 tests were performed.

RESULTS

The system demonstrated consistent results, with an average accuracy performance that was better than one millimeter (.75 ± SD .37 mm).

CONCLUSION

Independently acquired positional tracking accuracies exceed conventional in-market surgical navigation tracking systems and FDA standards. Importantly, the performance was achieved at two different institutions, using an international testing standard, and with a system that included a commercially available off-the-shelf wireless head mounted display and software.

An Integrated 3-Dimentional Navigation System Increases the Accuracy, Efficiency, and Safety of Percutaneous Thoracolumbar Pedicle Screw Placement in Minimally Invasive Approaches: A Randomized Cadaveric Study

STUDY DESIGN

Cadaveric study.

OBJECTIVES

The purpose of this study was to compare a novel, integrated 3D navigational system (NAV) and conventional fluoroscopy in the accuracy, efficiency, and radiation exposure of thoracolumbar percutaneous pedicle screw (PPS) placement.

METHODS

Twelve skeletally mature cadaveric specimens were obtained for twelve individual surgeons. Each participant placed bilateral PS at 11 segments, from T8 to S1. Prior to insertion, surgeons were randomized to the sequence of techniques and the side (left or right). Following placement, a CT scan of the spine was obtained for each cadaver, and an independent reviewer assessed the accuracy of screw placement using the Gertzbein grading system. Outcome metrics of interest included a comparison of breach incidence/severity, screw placement time, total procedure time, and radiation exposure between the techniques. Bivariate statistics were employed to compare outcomes at each level.

RESULTS

A total of 262 screws (131 using each technique) were placed. The incidence of cortical breaches was significantly lower with NAV compared to FG (9% vs 18%; P = .048). Of breaches with NAV, 25% were graded as moderate or severe compared to 39% in the FG subgroup (P = .034). Median time for screw placement was significantly lower with NAV (2.7 vs 4.1 min/screw; P = .012), exclusive of registration time. Cumulative radiation exposure to the surgeon was significantly lower for NAV-guided placement (9.4 vs 134 μGy, P = .02).

CONCLUSIONS

The use of NAV significantly decreased the incidence of cortical breaches, the severity of screw breeches, screw placement time, and radiation exposure to the surgeon when compared to traditional FG.

Design of an ultrasound-emitting drill guide for freehand pedicle screw navigation

BACKGROUND

Accurate pedicle screw placement in spinal surgery is critical as inaccuracies can lead to morbidity and suboptimal outcomes. Navigation and robotics have reduced malplacement rates, but their adoption is limited by high costs, learning curves, surgical time, and radiation. The authors propose an ultrasound-emitting and self-localising drill guide for precise screw placement that overcomes the limitations of current techniques.

MATERIALS AND METHODS

The preliminary configuration analysis involves systematically varying design parameters and assessing localization performance using lumbar spine MRI based simulations. The authors evaluate localization techniques based on accuracy and optimization capture range.

RESULTS

Results suggest that feasible designs can accurately estimate position. A promising design features a 5 mm radius cannula with ten 35mm-long ultrasound strips, 32 elements per strip, and a fanned-out emission profile. A multi-start active-set optimization algorithm with six initial estimates ensures reliable and efficient localization.

CONCLUSIONS

The simulation suggests that the proposed design can achieve sufficient localization accuracy for pedicle screw navigation. These findings will guide the fabrication of a novel ultrasound-emitting drill guide for further evaluation and physical testing.

Virtual and Augmented Reality in Spine Surgery: An Era of Immersive Healthcare

In the dynamic realm of spinal surgery, the integration of virtual reality (VR) and augmented reality (AR) technologies is heralding a transformative era. These cutting-edge tools are not only reshaping the training landscape for surgical trainees, offering immersive and interactive experiences but are also enhancing the surgical precision of seasoned professionals in the operating room. While the potential of VR and AR is vast, their adoption is tempered by significant costs and challenges in seamless integration. As the spinal surgery community looks ahead, it becomes imperative to emphasize the validation, reliability, and thorough cost-benefit analysis of these technologies. This article delves into the current applications, benefits, challenges, and future trajectories of VR and AR in spinal surgery, underscoring their pivotal role in the evolution of immersive healthcare.

Comparing Efficacy of Lumbar Disc Space Preparation via an Anterior-to-Psoas Approach Between Intraoperative Conventional Fluoroscopy and Computed Tomographic-Based Navigation System: A Cadaveric Study

OBJECTIVE

To compare the efficacy of intervertebral disc space preparation via an anterior-to-psoas (ATP) approach using conventional fluoroscopy (Flu) and computer tomography (CT)-based navigation by evaluating the disc remaining area.

METHODS

We equally assigned 24 lumbar disc levels from 6 cadavers into Flu and CT-based navigation (Nav) groups. Two surgeons performed disc space preparation using the ATP approach in both groups. Digital images of each vertebral endplate were obtained, and the remaining disc tissue was calculated in total and in quadrants. Operative time, number of attempts at disc removal, endplate violation area, number of endplate violation segments, and access angle were recorded.

RESULTS

The overall percentage of remaining disc tissue was significantly less in the Nav group than in the Flu group (32.7% vs. 43.3% respectively, P < 0.001). A significant difference was found in the posterior-ipsilateral (4.2% vs. 7.1%, P = 0.005) and posterior-contralateral (6.1% vs. 10.9%, P = 0.002) quadrants, respectively. No significant between-group difference was found concerning operative time, number of attempts at disc removal, endplate violation area, number of endplate violation segments, or access angle.

CONCLUSIONS

Intraoperative CT-based navigation may improve vertebral endplate preparation quality for an ATP approach, especially in the posterior quadrants. This technique may offer an effective alternative disc space and endplate preparation methods and may help enhance the fusion rates.

Trends and Long-term Health Care Utilization of Computer-assisted Neuronavigation in Spine Fusions: An Exact Matched Analysis of National Administrative Database

BACKGROUND

Computer-assisted neuronavigation (CAN) during spine fusions has increasingly been utilized in the United States. The aim of this study was to analyze the trends, health care utilization, and clinical outcomes associated with CAN use.

METHODS

The MarketScan database was queried using the ICD-9/10 and CPT 4th edition, from 2003 to 2019. We included patients aged ≥18 years with at least 2 years of follow-up. Outcomes were repeat/new fusions, length of stay (LOS), discharge disposition, hospital re-admissions, outpatient services, and medication refills for up to 24 months.

RESULTS

Of 183,620 patients who underwent spine fusions, 5046 (2.75%) were identified to have CAN utilized. CAN is increasingly being utilized for spine fusions since 2010, reaching 10.76% of all fusions in 2017, compared to 0.38% in 2010. CAN had no impact on LOS, home discharge, or complications at index hospitalization and 30-days post discharge. CAN was associated with lower rates of repeat fusions at 6 months (1% vs. 2%) and 24 months (5% vs. 6%), P < 0.05. Patients who underwent CAN had lower payments at 6 months ($5186 vs. $5527, P = 0.0159), 12 months ($10,267 v.s $11,262, P = 0.0207), and 24 months ($21,453 vs. $24,355, P = 0.0021).

CONCLUSIONS

CAN is increasing being used for spine fusions primarily for thoracolumbar procedures. No difference in complications, discharge disposition, and LOS were noted across the cohorts at index hospitalization, with higher index payments with CAN use. CAN was associated with lower rates of repeat fusions and corresponding health care utilization for up to 24 months.

The accuracy and learning curves of active and passive dynamic navigation-guided dental implant surgery: An in vitro study

OBJECTIVES

Infrared dynamic navigation principles can be categorized into active and passive navigation systems based on whether the surgical instruments can emit or only reflect light, respectively. This in vitro study aimed to compare the accuracy of implant placement and the learning curves of both active and passive dynamic navigation systems using different registration methods.

METHODS

Implants (n=704) were placed in 64 sets of models and divided into active (Yizhime, DCARER, Suzhou, China) and passive (Iris-Clinic, EPED, Kaohsiung, China) dynamic navigation groups. Both marker point-based registration (M-PBR) and feature point-based registration (F-PBR) were employed by two groups mentioned above. Based on preoperative and postoperative cone-beam computed tomography imaging, the coronal, midpoint, apical, and angular deviations were analyzed from 2D and 3D views. The operation time was recorded for each group.

RESULTS

The active dynamic navigation group exhibited significantly greater accuracy than the passive dynamic navigation group for outcome variables (angular deviation, 4.13 ± 2.39° and 4.62 ± 3.32°; coronal global deviation, 1.48 ± 0.60 and 1.86 ± 1.12 mm; apical global deviation, 1.75 ± 0.81 and 2.20 ± 1.68 mm, respectively). Significant interaction effects were observed for both registration methods and four quadrants with different dynamic navigation systems. Learning curves for the two dynamic navigation groups approached each other after 12 procedures, and finally converged after 27 procedures.

CONCLUSIONS

The accuracy of active dynamic navigation system was superior to that of passive dynamic navigation system. Different combinations of dynamic navigation systems, registration methods, and implanted quadrants displayed various interactions.

CLINICAL SIGNIFICANCE

Our findings could provide guidance for surgeons in choosing an appropriate navigation system use in various implant surgeries. Furthermore, the time required by surgeons to master the technique was calculated for reference. Nevertheless, there are certain limitations to this in vitro study, and therefore further research is required.

Radiation Dose Reduction and Surgical Efficiency Improvement in Endoscopic Transforaminal Lumbar Interbody Fusion Assisted by Intraoperative O-arm Navigation: A Retrospective Observational Study

Objective: Endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) has gained increasing popularity among spine surgeons. However, with the use of fluoroscopy, intraoperative radiation exposure remains a major concern. Here, we aim to introduce Endo-TLIF assisted by O-arm-based navigation and compare the results between O-arm navigation and fluoroscopy groups.Methods: Sixty-four patients were retrospectively analyzed from May 2019 to September 2020; the nonnavigation group comprised 34 patients, and the navigation group comprised 30 patients. Data on radiation dose, blood loss, postoperative drains, surgery time, complications, and length of hospital stay (LOS) were collected. Clinical outcomes were evaluated from postoperative data such as fusion rate, Oswestry Disability Index (ODI), and visual analogue scale (VAS). Radiation dose and surgery time were selected as primary outcomes; the others were second outcomes.Results: All patients were followed up for at least 12 months. No significant differences were detected in intraoperative hemorrhage, postoperative drains, hospital LOS, or complications between the 2 groups. The radiation dose was significantly lower in the navigation group compared with the nonnavigation group. The time of cannula placement and pedicle screw fixation was significantly reduced in the navigation group. No significant differences were detected between the clinical outcomes in the 2 groups (VAS and ODI scores).Conclusion: The present study demonstrates that O-arm-assisted Endo-TLIF is efficient and safe. Compared with fluoroscopy, O-arm navigation could reduce the radiation exposure and surgical time in Endo-TLIF surgery, with similar clinical outcomes. However, the higher doses exposed to patients remains a negative effect of this technology.

Pre- and intraoperative thoracic spine localization techniques: a systematic review

OBJECTIVE

In the era of modern medicine with an armamentarium full of state-of-the art technologies at our disposal, the incidence of wrong-level spinal surgery remains problematic. In particular, the thoracic spine presents a challenge for accurate localization due partly to body habitus, anatomical variations, and radiographic artifact from the ribs and scapula. The present review aims to assess and describe thoracic spine localization techniques.

METHODS

The authors performed a literature search using the PubMed database from 1990 to 2020, compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A total of 27 articles were included in this qualitative review.

RESULTS

A number of pre- and intraoperative strategies have been devised and employed to facilitate correct-level localization. Some of the more well-described approaches include fiducial metallic markers (screw or gold), metallic coils, polymethylmethacrylate, methylene blue, marking wire, use of intraoperative neuronavigation, intraoperative localization techniques (including using a needle, temperature probe, fluoroscopy, MRI, and ultrasonography), and skin marking.

CONCLUSIONS

While a number of techniques exist to accurately localize lesions in the thoracic spine, each has its advantages and disadvantages. Ultimately, the localization technique deployed by the spine surgeon will be patient-specific but often based on surgeon preference.

Pedicle Screw Placement Using Intraoperative Computed Tomography and Computer-Aided Spinal Navigation Improves Screw Accuracy and Avoids Postoperative Revisions: Single-Center Analysis of 1400 Pedicle Screws

OBJECTIVE

Intraoperative computed tomography and navigation (iCT-Nav) is increasingly used to aid spinal instrumentation. We aimed to document the accuracy and revision rate of pedicle screw placement across many screws placed using iCT-Nav. We also assess patient-level factors predictive of high-grade pedicle breach.

METHODS

Medical records of patients who underwent iCT-Nav pedicle screw placement between 2015 and 2017 at a single center were retrospectively reviewed. Screw placement accuracy was individually assessed for each screw using the 2-mm incremental grading system for pedicle breach. Predictors of high-grade (>2 mm) breach were identified using multiple logistic regression.

RESULTS

In total, 1400 pedicle screws were placed in 208 patients undergoing cervicothoracic (29; 13.9%), thoracic (30; 14.4), thoracolumbar (19; 9.1%) and lumbar (130; 62.5%) surgeries. iCT-Nav afforded high-accuracy screw placement, with 1356 of 1400 screws (96.9%) being placed accurately. In total, 37 pedicle screws (2.64%) were revised intraoperatively during the index surgery across 31 patients, with no subsequent returns to the operating room because of screw malpositioning. After correcting for potential confounders, males were less likely to have a high-grade breach (odds ratio [OR] 0.21; 95% confidence interval [CI] 0.10-0.59, P = 0.003) whereas lateral (OR 6.21; 95% CI 2.47-15.52, P < 0.001) or anterior (OR 5.79; 95% CI2.11-15.88, P = 0.001) breach location were predictive of a high-grade breach.

CONCLUSIONS

iCT-Nav with postinstrumentation intraoperative imaging is associated with a reduced need for costly postoperative return to the operating room for screw revision. In comparison with studies of navigation without iCT where 1.5%-1.7% of patients returned for a second surgery, we report 0 revision surgeries due to screw malpositioning.

Computed Tomography-Based Navigation System in Current Spine Surgery: A Narrative Review

The number of spine surgeries using instrumentation has been increasing with recent advances in surgical techniques and spinal implants. Navigation systems have been attracting attention since the 1990s in order to perform spine surgeries safely and effectively, and they enable us to perform complex spine surgeries that have been difficult to perform in the past. Navigation systems are also contributing to the improvement of minimally invasive spine stabilization (MISt) surgery, which is becoming popular due to aging populations. Conventional navigation systems were based on reconstructions obtained by preoperative computed tomography (CT) images and did not always accurately reproduce the intraoperative patient positioning, which could lead to problems involving inaccurate positional information and time loss associated with registration. Since 2006, an intraoperative CT-based navigation system has been introduced as a solution to these problems, and it is now becoming the mainstay of navigated spine surgery. Here, we highlighted the use of intraoperative CT-based navigation systems in current spine surgery, as well as future issues and prospects.

Propensity-Matched Comparison of 90-Day Complications in Robotic-Assisted Versus Non-Robotic Assisted Lumbar Fusion

STUDY DESIGN

Retrospective single center propensity-matched observational cohort study that included patients who underwent 1- to 3-level lumbar fusion surgery for degenerative conditions.

OBJECTIVE

To compare 90-day complication rates between robotic-assisted and non-robotic-assisted lumbar spinal fusions in propensity-matched cohorts.

SUMMARY OF BACKGROUND DATA

A recent administrative database (PearlDiver) study reported increased 30-day complications with the utilization of robotic-assisted enabling technology.

METHODS

Of 146 robotic-assisted cases that met inclusion criteria, 114 were successfully propensity matched to 114 patients from 214 cases who had 1 to 3 level lumbar fusion without robotic assistance based on age, sex, body mass index, smoking status, American Society of Anesthesiologist grade, number of surgical levels, primary versus revision, and surgical approach (posterior-only or anterior-posterior). We excluded tumor, trauma, infection, or deformity cases. Outcomes included surgical and medical (major/minor) complications at intraoperative, immediately postoperative, 30- and 90-day postoperative intervals, including reoperations, and readmissions within 90 days.

RESULTS

All cause intraoperative complication rates were similar between non-robotic-assisted (5.3%) and robotic-assisted groups (10.5%, P = 0.366). Immediate postoperative medical complication rate was also similar between non-robotic-assisted (6.1%) and robotic-assisted groups (1.8%, P = 0.089). Thirty-day complication rates, 90-day complication rates, reoperation rates, and readmission rates showed no difference between non-robotic-assisted and robotic-assisted groups. There was no difference between return to OR for infection between the cohorts (non-robotic-assisted: 6 [5%] vs. robotic-assisted: 1 [0.8%], P = 0.119). There was however improved length of stay (LOS) in the robotic-assisted group compared with non-robotic-assisted group (2.5 vs. 3.17 days, P = 0.018).

CONCLUSION

In propensity-matched cohorts, patients undergoing 1- to 3-level robotic-assisted posterior lumbar fusion for degenerative conditions did not have increased 90-day complication rate, and had a shorter length of stay compared with non-robotic-assisted patients. There findings differ from a prior administrative database study as the robotic-assisted group in the current study had 0% return to OR for malpositioned screws and 0.8% return to OR for infection.Level of Evidence: 2.

Intraoperative Navigation in Spine Surgery: Effects On Complications and Reoperations

INTRODUCTION

Intraoperative navigation during spine surgery improves pedicle screw placement accuracy. However, limited studies have correlated navigation with clinical factors including operative time and safety. This study compares complications and reoperations between surgeries with and without navigation.

METHODS

Posterior cervical and lumbar fusions and deformity surgeries from 2011-2018 were queried from the NSQIP database and divided by navigation use. Patients aged >89, deformity patients aged <25, and patients undergoing surgery for tumors, fractures, infections, or non-elective indications were excluded. Demographics and perioperative factors were compared with univariate analysis. Outcomes were compared with multivariable logistic regression adjusting for age, sex, BMI, ASA class, surgical region, and multiple levels. Outcomes were also compared stratifying by revision status.

RESULTS

Navigated surgery patients had higher ASA status (p<0.0001), more multiple-level surgeries (p<0.0001), and longer operations (p<0.0001). Adjusted analysis revealed navigated lumbar surgeries had lower odds of complications (OR=0.82, 95%CI=0.77-0.90, p<0.0001), blood transfusion (OR=0.79, 95%CI=0.72-0.87, p<0.0001), and wound debridement/drainage (OR=0.66, 95%CI=0.44-0.97, p=0.04) compared to non-navigated procedures. Navigated cervical fusions had increased odds of transfusion (OR=1.53, 95%CI=1.06-2.23, p=0.02). Navigated primary fusions had decreased odds of complications (OR=0.91, 95%CI=0.85-0.98, p=0.01); no difference was found in revisions (OR=0.89, 95%CI=0.69-1.14, p=0.34).

CONCLUSIONS

Navigated surgery patients experienced longer operations due to a combination of time using navigation, more multi-level procedures and larger comorbidity burden, without differences in infections. There were fewer complications and wound washouts in navigated lumbar surgeries due to a higher percentage of minimally invasive cases. Co-utilization of navigation and minimally invasive surgery may benefit properly indicated patients.

Utilization trends and outcomes of computer-assisted navigation in spine fusion in the United States

BACKGROUND CONTEXT

Computer-assisted navigation (CAN) has emerged in spine surgery as an approach to improve patient outcomes. While there is substantial evidence demonstrating improved pedicle screw accuracy in CAN as compared to conventional spinal fusion (CONV), there is limited data regarding clinical outcomes and utilization trends in the United States.

PURPOSE

The purpose of this study was to determine the utilization rates of CAN in the United States, identify patient and hospital trends associated with both techniques, and to compare their results.

STUDY DESIGN

Retrospective review of national database.

PATIENT SAMPLE

Nationwide Inpatient Sample (NIS), United States national database.

OUTCOME MEASURES

CAN utilization, mortality, medical complications, neurologic complications, discharge destination, length of hospital stay, cost of hospital stay.

METHODS

The NIS database was queried to identify patients undergoing spinal fusion with CAN or CONV. CAN and CONV utilization were tracked by year and anatomic location (cervical, thoracic, lumbar/lumbosacral). Patient demographics, hospital characteristics, index length of stay (LOS), and cost of stay (COS) were compared between the cohorts. After multivariate adjustment, index hospitalization clinical outcomes were compared.

RESULTS

A total of 4,275,413 patients underwent spinal fusion surgery during the study period (2004 to 2014). CONV was performed in 98.4% (4,208,068) of cases and CAN was performed in 1.6% (67,345) of cases. The utilization rate of CAN increased from 0.04% in 2004 to 3.3% in 2014. Overall, CAN was performed most commonly in the lumbar/lumbosacral region (70.4%) compared to the cervical (20.4%) or thoracic (9.2%) regions. When normalized to region-specific rates of fusion with any technique, the proportional utilization of CAN was highest in the thoracic spine (2.7%), followed by the lumbar/lumbosacral (2.2%) and cervical (0.9%) regions. CAN utilization was positively correlated with patient factors including increasing age and number of medical comorbidities. Multivariate adjusted clinical outcomes demonstrated that compared to CONV, CAN was associated with a statistically significant decreased risk of mortality (0.28% vs 0.31%, OR=0.67, 95% CI: 0.46-0.97, p=.035) and increased risk of blood transfusions (9.1% vs 6.7%, OR=1.19, 95% CI: 1.02-1.39, p=.032). However, there was no difference in risk of neurologic complications. CAN patients had an increased average LOS (4.44 days vs. 3.97 days, p<.0001) and average COS ($34,669.49 vs $26,784.62, p<.0001) compared to CONV patients.

CONCLUSIONS

CAN utilization increased in the United States from 2004-2014. Use of CAN was proportionately higher in the thoracic and lumbar/lumbosacral regions and in older patients with more comorbidities. Given the continued trend towards increased CAN utilization, large-scale studies are needed to determine the impact of this technology on long-term clinical outcomes.

Prevalence of spine surgery navigation techniques and availability in Africa: A cross-sectional study

Background

Africa has a large burden of spine pathology but has limited and insufficient infrastructure to manage these spine disorders. Therefore, we conducted this e-survey to assess the prevalence and identify the determinants of the availability of spine surgery navigation techniques in Africa.

Materials and methods

A two-part questionnaire was disseminated amongst African neurological and orthopedic surgery consultants and trainees from January 24 to February 23, 2021. The Chi-Square, Fisher Exact, and Kruskal-Wallis tests were used to evaluate bivariable relationships, and a p-value <0.05 was considered statistically significant.

Results

We had 113 respondents from all regions of Africa. Most (86.7 %) participants who practiced or trained in public centers and centers had an annual median spine case surgery volume of 200 (IQR = 190) interventions. Fluoroscopy was the most prevalent spine surgery navigation technique (96.5 %), followed by freehand (55.8 %), stereotactic without intraoperative CT scan (31.9 %), robotic with intraoperative CT scan (29.2 %), stereotactic with intraoperative CT scan (8.8 %), and robotic without intraoperative CT scan (6.2 %). Cost of equipment (94.7 %), lack of trained staff to service (63.7 %), or run the equipment (60.2 %) were the most common barriers to the availability of spine instrumentation navigation. In addition, there were significant regional differences in access to trained staff to run and service the equipment (P = 0.001).

Conclusion

There is a need to increase access to more advanced navigation techniques, and we identified the determinants of availability.

•

African spine surgery has regional disparities in navigation techniques.

•

Fluoroscopy is the most prevalent navigation technique.

•

Cost and lack of trained personnel are the most significant barriers.

Incorporating New Technologies to Overcome the Limitations of Endoscopic Spine Surgery: Navigation, Robotics, and Visualization

Recently, spine surgery has gradually evolved from conventional open surgery to minimally invasive surgery, and endoscopic spine surgery (ESS) has become an important procedure in minimally invasive spine surgery. With improvements in the optics, spine endoscope, endoscopic burr, and irrigation pump, the indications of ESS are gradually widening from lumbar to cervical and thoracic spine. ESS was not only used previously for disc herniations that were contained without migration but is also used currently for highly migrated disc herniations and spinal stenosis; thus, the indications of ESS will be further expanded. Although ESS has certain advantages such as less soft tissue dissection and muscle trauma, reduced blood loss, less damage to the epidural blood supply and consequent less epidural fibrosis and scarring, reduced hospital stay, early functional recovery, and improvement of quality of life as well as better cosmesis, several obstacles remain for ESS to be widespread because it has a steep learning curve and surgical outcome is strongly dependent on the surgeon's skillfulness. A solid surgical technique requires reproducibility and ensured safety in addition to surgical outcomes. In this review article, how to improve ESS was investigated by grafting novel technologies such as navigation, robotics, and 3-dimensional and ultraresolution visualization.

Anterior Cervical Osteophyte Resection for Treatment of Dysphagia

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVES

When anterior cervical osteophytes become large enough, they may cause dysphagia. There is a paucity of work examining outcomes and complications of anterior cervical osteophyte resection for dysphagia.

METHODS

Retrospective review identified 19 patients who underwent anterior cervical osteophyte resection for a diagnosis of dysphagia. The mean age was 71 years and follow-up, 4.7 years. The most common level operated on was C3-C4 (13, 69%).

RESULTS

Following anterior cervical osteophyte resection, 79% of patients had improvement in dysphagia. Five patients underwent cervical fusion; there were no episodes of delayed or iatrogenic instability requiring fusion. Fusion patients were younger (64 vs 71 years, P = .05) and had longer operative times (315 vs 121 minutes, P = .01). Age of 75 years or less trended toward improvement in dysphagia (P = .09; OR = 18.8; 95% CI 0.7-478.0), whereas severe dysphagia trended toward increased complications (P = .07; OR = 11.3; 95% CI = 0.8-158.5). Body mass index, use of an exposure surgeon, diffuse idiopathic skeletal hyperostosis diagnosis, surgery at 3 or more levels, prior neck surgery, and fusion were not predictive of improvement or complication.

CONCLUSIONS

Anterior cervical osteophyte resection improves swallowing function in the majority of patients with symptomatic osteophytes. Spinal fusion can be added to address stenosis and other underlying cervical disease and help prevent osteophyte recurrence, whereas intraoperative navigation can be used to ensure complete osteophyte resection without breaching the cortex or entering the disc space. Because of the relatively high complication rate, patients should undergo thorough multidisciplinary workup with swallow evaluation to confirm that anterior cervical osteophytes are the primary cause of dysphagia prior to surgery.

Posterior hemivertebra resection and short-segment fusion with lateral mass screws in congenital scoliosis: a novel strategy for the resource-limited setting

Background

Posterior hemivertebra resection and short-segment fusion with pedicle screws are an established treatment in congenital scoliosis, which require pediatric-specific instrumentation. The purpose of this study was to report the results of utilizing cervical lateral mass screws instead of pedicle screws in the treatment of congenital scoliosis in children younger than 5 years old.

Methods

In an IRB-approved retrospective chart review study, patients <5 years old with congenital scoliosis who underwent posterior hemivertebra resection and fusion with lateral mass screws from 2013 to 2017 were included. Demographic information, pre- and post-operative radiographs, complications, and outcomes were extracted from the charts.

Results

Twenty-three patients were included in the final analysis with a mean age of 40 months, of which 14 were female. Patients were followed for a mean of 51.3±13.2 months. The mean blood loss was 210ml, and patients were hospitalized for a mean of 4 days post-operatively. The correction rate of the main coronal curve, compensatory cranial curve, compensatory caudal curve, and segmental sagittal curve was 74.8%, 68%, 65.2%, and 68.9%, respectively. Three complications were observed: one intra-operative pedicle fracture, one case of implant failure, and one deep surgical-site infection, all of which were successfully managed.

Conclusions

Our findings suggest that adult lateral mass screws can be used for transpedicular fixation of the thoracic and lumbar vertebrae in low-resource settings where pediatric-specific pedicle instruments are not readily available. The correction rate, outcomes, and complications are similar and comparable to pediatric-specific pedicle screws, in addition to being low-profile and less bulky compared to adult implants.

Augmented Reality in Orthopedic Surgery Is Emerging from Proof of Concept Towards Clinical Studies: a Literature Review Explaining the Technology and Current State of the Art

PURPOSE OF REVIEW

Augmented reality (AR) is becoming increasingly popular in modern-day medicine. Computer-driven tools are progressively integrated into clinical and surgical procedures. The purpose of this review was to provide a comprehensive overview of the current technology and its challenges based on recent literature mainly focusing on clinical, cadaver, and innovative sawbone studies in the field of orthopedic surgery. The most relevant literature was selected according to clinical and innovational relevance and is summarized.

RECENT FINDINGS

Augmented reality applications in orthopedic surgery are increasingly reported. In this review, we summarize basic principles of AR including data preparation, visualization, and registration/tracking and present recently published clinical applications in the area of spine, osteotomies, arthroplasty, trauma, and orthopedic oncology. Higher accuracy in surgical execution, reduction of radiation exposure, and decreased surgery time are major findings presented in the literature. In light of the tremendous progress of technological developments in modern-day medicine and emerging numbers of research groups working on the implementation of AR in routine clinical procedures, we expect the AR technology soon to be implemented as standard devices in orthopedic surgery.

Use of intraoperative navigation for posterior spinal fusion in adolescent idiopathic scoliosis surgery is safe to consider

PURPOSE

The use of image-guided stereotactic navigation is increasing in use in treating AIS; however, no studies have investigated perioperative outcomes and short-term adverse events compared with non-navigated procedures. The aim of the present study is to use a large national pediatric database to assess the rate of utilization of intraoperative navigation in pediatric patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis (AIS) and to compare thirty-day outcomes of navigated vs. non-navigated surgery.

METHODS

The NSQIP-Pediatric database was queried for cases of posterior fusion for AIS. Patients were stratified by whether or not a concurrent code for stereotactic navigation was used (CPT 61,783). Year of procedure, demographics, comorbidities, operative variables and perioperative adverse outcomes were abstracted and assessed using univariate and multivariate analysis.

RESULTS

Overall, 12,739 non-navigated patients and 340 navigated patients were identified. The use of navigation increased from 0.5% of cases in 2012 to 5.2% of cases in 2018. Demographics, comorbidities, and number of levels fused did not differ between navigated and non-navigated patients. Navigated cases were on average 41 min longer than non-navigated cases (268.6 vs. 309.6 min p < 0.001), with 9.84% more cases requiring transfusion (65.0% vs 75.6%, p < 0.001). Hospital stay for navigated cases was an average of 0.4 days shorter (3.9 days vs 4.3 days, p = 0.001). On multivariate analysis, navigated cases had higher odds of prolonged surgery (OR = 2.13, p < 0.001) and lower odds of prolonged length of stay (OR = 0.28, p < 0.001).

CONCLUSION

Although the use of navigation for AIS posterior fusion was associated with longer operative time, post-operative hospital stay was shorter and other perioperative adverse outcomes were not significantly different between groups.

The Nottingham radiation protocol for O-arm navigation in paediatric deformity patients: a feasibility study

BACKGROUND

O-arm assisted pedicle screw placement has been proven to be more accurate than free-hand technique. Radiation exposure remains the primary drawback. We determined the feasibility and safety of a reduced radiation protocol in paediatric patients undergoing scoliosis correction.

METHODS

A reduced radiation protocol for a medtronic O-arm navigational system was devised. 3D CT reconstructions of an anthropomorphic pelvic phantom indicated adequate image quality after reduction to 14% of current manufacturer default factors. A feasibility study to test the image quality was undertaken on four patients, one with syndromic and three with idiopathic scoliosis each receiving progressively reducing radiation exposure of 60%, 50%, 40% and 14% of what would have been delivered using the manufacturer default protocol. This represented 32% of the mayo clinic protocol. It was achieved by reducing the x-ray tube current to 10 mA while keeping the tube potential at 90 kVp.

RESULTS

A low dose O-arm protocol was able to generate adequate image quality while delivering as little as 14% (for lumbar region reconstructions) of the recommended protocol radiation dose. The total radiation dose delivered with this protocol was approximately 0.8 milliSieverts for a single spin. This effective dose represents < 1/3 of average UK and < 1/6 average US annual radiation exposure. There were no neurological or implant-related complications.

CONCLUSIONS

Our low dose O-arm radiation protocol significantly reduces the radiation exposure compared to the manufacturer recommended Mayo clinic protocol providing operational image quality to allow accurate screw placement in spinal deformity.

Use of an inertial measurement unit sensor in pedicle screw placement improves trajectory accuracy

Ascertaining the accuracy of the pedicle screw (PS) trajectories is important as PS malpositioning can cause critical complications. We aimed to determine the angle range over which estimation is unreliable; build a low-cost PS placement support system that uses an inertial measurement unit (IMU) to enable the monitoring of surgical tools and PS trajectories, and determine the situations where IMU support would be most beneficial. In PS insertion experiments, we used cadaver samples that included lumbar porcine spines. Computed tomography images obtained before and after PS insertion were viewed. Offsets between the planned and implanted PS trajectories in the freehand and IMU-assisted groups were analyzed. The PS cortical bone breaches were classified according to the Gertzbein and Robbins criteria (GRC). Added head-down tilted sample experiments were repeated wherein we expected a decreased rostro-caudal rotational accuracy of the PS according to the angle estimation ability results. Evaluation of the PS trajectory accuracy revealed no significant advantage of IMU-assisted rostro-caudal rotational accuracy versus freehand accuracy. According to the GRC, IMU assistance significantly increased the rate of clinically acceptable PS positions (RoCA) than the freehand technique. In the head-down tilted sample experiments, IMU assist provided increased accuracies with both rostro-caudal and medial rotational techniques when compared with the freehand technique. In the freehand group, RoCA was significantly decreased in samples with rostral tilting relative to that in the samples without. However, In the IMU-assisted group, no significant difference in RoCA between the samples with and without head-down tilting was observed. Even when the planned PS medial and/or rostro-caudal rotational angle was relatively large and difficult to reproduce manually, IMU-support helped maintain the PS trajectory accuracy and positioning safety. IMU assist in PS placement was more beneficial, especially for larger rostro-caudal and/or medial rotational pedicle angles.

Three-dimensional Printed Drill Guides Versus Fluoroscopic-guided Freehand Technique for Pedicle Screw Placement: A Systematic Review and Meta-analysis of Radiographic, Operative, and Clinical Outcomes

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

The objective of this study was to compare surgical, clinical, and radiographic outcomes of 3-dimensional printed (3DP) drill guides to the fluoroscopic-guided, freehand placement of pedicle screws in the spine.

SUMMARY OF BACKGROUND DATA

3DP is a budding technology in spine surgery and has recently been applied to patient-specific drill guides for pedicle screw placement. Several authors have reported the benefits of these drill guides, but no clear consensus exists on their utility.

MATERIALS AND METHODS

A comprehensive search of the literature was conducted and independent reviewers assessed eligibility for included studies. Outcomes analyzed included: total operation time, estimated blood loss, screw accuracy, pain score, Japanese Orthopedic Association score, and postoperative complications. Weighted mean differences (WMD) and weighted risk differences were calculated using a random-effects model.

RESULTS

Six studies with a total of 205 patients were included. There were significantly lower operation times [WMD=-32.32 min, 95% confidence interval (CI)=-53.19 to -11.45] and estimated blood loss (WMD=-51.42 mL, 95% CI=-81.12 to -21.72) in procedures performed with 3DP drill guides as compared with freehand technique. The probability of "excellent" screw placement was significantly higher in 3DP guides versus freehand (weighted risk difference=-0.12, 95% CI=-0.17 to 0.07); however, no differences were observed in "poor" or "good" screw placement. There were no significant differences between groups in pain scores or Japanese Orthopedic Association scores. No difference in the rate of surgical complications was noted between the groups.

CONCLUSIONS

Pedicle screws placed with 3DP drill guides may result in shorter operative time, less blood loss, and a greater probability of excellent screw placement as compared with those placed with freehand techniques. We conclude that 3DP guides may potentially develop into an efficient and accurate option for pedicle screw placement. However, more prospective, randomized controlled trials are needed to strengthen the confidence of these conclusions.

LEVEL OF EVIDENCE

Level III.

Is it mandatory to routinely use image intensifier during scoliosis surgery? – Results of an email survey

Background

Methods

Results

Conclusions

Accuracy of Thoracolumbar Pedicle Screw Insertion Based on Routine Use of Intraoperative Imaging and Navigation

Study Design

Retrospective review.

Purpose

To determine the accuracy of thoracolumbar pedicle screw insertion with the routine use of three-dimensional (3D) intraoperative imaging and navigation over a large series of screws in an Asian population.

Overview of Literature

The use of 3D intraoperative imaging and navigation in spinal surgery is aimed at improving the accuracy of pedicle screw insertion. This study analyzed 2,240 pedicle screws inserted with the routine use of intraoperative navigation. It is one of very few studies done on an Asian population with a large series of screws.

Methods

Patients who had undergone thoracolumbar pedicle screws insertion using intraoperative imaging and navigation between 2009 and 2017 were retrospectively analyzed. Computed tomography (CT) images acquired after the insertion of pedicle screws were analyzed for breach of the pedicle wall. The pedicle screw breaches were graded according to the Gertzbein classification. The breach rate and revision rate were subsequently calculated.

Results

A total of 2,240 thoracolumbar pedicle screws inserted under the guidance of intraoperative navigation were analyzed, and the accuracy of the insertion was 97.41%. The overall breach rate was 2.59%, the major breach rate was 0.94%, and the intraoperative screw revision rate was 0.7%. There was no incidence of return to the operating theater for revision of screws.

Conclusions

The routine use of 3D navigation and intraoperative CT imaging resulted in consistently accurate pedicle screw placement. This improved the safety of spinal instrumentation and helped in avoiding revision surgery for malpositioned screws.

The effect of simulation training on resident proficiency in thoracolumbar pedicle screw placement using computer-assisted navigation

OBJECTIVE

Residency work-hour restrictions necessitate efficient, reproducible training. Simulation training for spinal instrumentation placement shows significant benefit to learners' subjective and objective proficiency. Cadaveric laboratories are most effective but have high cost and low availability. The authors' goal was to create a low-cost, efficient, reproducible spinal instrumentation placement simulation curriculum for neurosurgery and orthopedic surgery residents using synthetic models and 3D computer-assisted navigation, assessing subjective and objective proficiency with placement of thoracolumbar pedicle screws.

METHODS

Fifteen neurosurgery and orthopedic surgery residents participated in a standardized curriculum with lecture followed by two separate sessions of thoracolumbar pedicle screw placement in a synthetic spine model utilizing 3D computer-assisted navigation. Data were collected on premodule experience, time and accuracy of screw placement, and both subjective and objective ratings of proficiency.

RESULTS

Fifteen of 15 residents demonstrated improvement in subjective (Physician Performance Diagnostic Inventory Scale [PPDIS]) and 14 in objective (Objective Structured Assessment of Technical Skills [OSATS]) measures of proficiency in navigated screw placement with utilization of this curriculum (p < 0.001 for both), regardless of the number of cases of previous experience using thoracolumbar spinal instrumentation. Fourteen of 15 residents demonstrated decreased time per screw placement from session 1 to session 2 (p = 0.006). There was no significant difference in pedicle screw accuracy between session 1 and session 2.

CONCLUSIONS

A standardized curriculum using synthetic simulation training for navigated thoracolumbar pedicle screw placement results in significantly improved resident subjective and objective proficiency. Development of a nationwide competency curriculum using simulation training for spinal instrumentation placement should be considered for safe, efficient resident training.

Conventional versus stereotactic image guided pedicle screw placement during spinal deformity correction: a retrospective propensity score-matched study of a national longitudinal database

PURPOSE/AIM

To compare complications, readmissions, revisions, and payments between navigated and conventional pedicle screw fixation for treatment of spine deformity.

METHODS

The Thomson Reuters MarketScan national longitudinal database was used to identify patients undergoing osteotomy, posterior instrumentation, and fusion for treatment of spinal deformity with or without image-guided navigation between 2007-2016. Conventional and navigated groups were propensity-matched (1:1) to normalize differences between demographics, comorbidities, and surgical characteristics. Clinical outcomes and charges were compared between matched groups using bivariate analyses.

RESULTS

A total of 4,604 patients were identified as having undergone deformity correction, of which 286 (6.2%) were navigated. Propensity-matching resulted in a total of 572 well-matched patients for subsequent analyses, of which half were navigated. Rate of mechanical instrumentation-related complications was found to be significantly lower for navigated procedures (p = 0.0371). Navigation was also associated with lower rates of 90-day unplanned readmissions (p = 0.0295), as well as 30- and 90-day postoperative revisions (30-day: p = 0.0304, 90-day: p = 0.0059). Hospital, physician, and total payments favored the conventional group for initial admission (p = 0.0481, 0.0001, 0.0019, respectively); however, when taking into account costs of readmissions, hospital payments became insignificantly different between the two groups.

CONCLUSIONS

Procedures involving image-guided navigation resulted in decreased instrumentation-related complications, unplanned readmissions, and postoperative revisions, highlighting its potential utility for the treatment of spine deformity. Future advances in navigation technologies and methodologies can continue to improve clinical outcomes, decrease costs, and facilitate widespread adoption of navigation for deformity correction.

Image-Guided Navigation and Robotics in Spine Surgery

Image guidance (IG) and robotics systems are becoming more widespread in their utilization and can be invaluable intraoperative adjuncts during spine surgery. Both are highly reliant upon stereotaxy and either pre- or intraoperative radiographic imaging. While user-operated IG systems have been commercially available longer and subsequently are more widely utilized across centers, robotics systems provide unique theoretical advantages over freehand and IG techniques for placing instrumentation within the spine. While there is a growing plethora of data showing that IG and robotic systems decrease the incidence of malpositioned screws, less is known about their impact on clinical outcomes. Both robotics and IG may be of particular value in cases of substantial deformity or complex anatomy. Indications for the use of these systems continue to expand with an increasing body of literature justifying their use in not only guiding thoracolumbar pedicle screw placement, but also in cases of cervical and pelvic instrumentation as well as spinal tumor resection. Both techniques also offer the potential benefit of reducing occupational exposures to ionizing radiation for the operating room staff, the surgeon, and the patient. As the use of IG and robotics in spine surgery continues to expand, these systems' value in improving surgical accuracy and clinical outcomes must be weighed against concerns over cost and workflow. As newer systems incorporating both real-time IG and robotics become more utilized, further research is necessary to better elucidate situations where these systems may be particularly beneficial in spine surgery.

Evolving Navigation, Robotics, and Augmented Reality in Minimally Invasive Spine Surgery

Innovative technology and techniques have revolutionized minimally invasive spine surgery (MIS) within the past decade. The introduction of navigation and image-guided surgery has greatly affected spinal surgery and will continue to make surgery safer and more efficient. Eventually, it is conceivable that fluoroscopy will be completely replaced with image guidance. These advancements, among others such as robotics and virtual and augmented reality technology, will continue to drive the value of 3-dimensional navigation in MIS. In this review, we cover pertinent features of navigation in MIS and explore their evolution over time. Moreover, we aim to discuss the key features germane to surgical advancement, including technique and technology development, accuracy, overall health care costs, operating room time efficiency, and radiation exposure.

3D-printed model-guided endoscopic evacuation for basal ganglia hemorrhage

The purpose of this study was to investigate the effectiveness and practicality of 3D-printed model-guided endoscopic surgery for the treatment of basal ganglia hemorrhage. The authors retrospectively analyzed the data of all patients who underwent endoscopic evacuation of basal ganglia hemorrhage in the Department of Neurosurgery at Dalang Hospital and Shipai Hospital between December 2017 and February 2019. Twelve patients, in whom the 3D-printed model guidance was used for endoscopic evacuation, were included in this investigation. Using 3D reconstructed technology, we designed the appropriate surgical approach. Then, an individualized facial model with the guide orifice was printed by a 3D printer. Further, the 3D-printed model was employed to guide the insertion of the endoscope sheath. As a result, the average evacuation rate was 97.2% (range 90.1-100.0%). The GCS and mRS score were improved in each patient from admission to discharge examination. All patients had a good prognosis based on their functional independence measure (FIM) scores at the 6-month follow-up. The 3D-printed model-guided endoscopic evacuation was effective and safe for basal ganglia hemorrhage. This technique deserves further investigation to determine its role in intracerebral hemorrhage management.

Computer-assisted navigation in complex cervical spine surgery: tips and tricks

Stereotactic navigation is quickly establishing itself as the gold standard for accurate placement of spinal instrumentation and providing real-time anatomic referencing. There have been substantial improvements in computer-aided navigation over the last decade producing improved accuracy with intraoperative scanning while shortening registration time. The newest iterations of modeling software create robust maps of the anatomy while tracking software localizes instruments in multiple display modes. As a result, stereotactic navigation has become an effective adjunct to spine surgery, particularly improving instrumentation accuracy in the setting of atypical anatomy. This article provides an overview of stereotactic navigation applied to complex cervical spine surgery, details the means for registration and direct referencing, and shares our preferred methods to implement this promising technology.

[Scatter Radiation Intensities during Transforaminal Lumbar Interbody Fusion Using a Mobile C-arm System]

The purpose of this study was to measure the scatter radiation intensity during transforaminal lumbar interbody fusion using a mobile C-arm system (Arcadis Orbic 3D; Siemens) and minimize radiation exposure. Dosimetry was performed with anterior-posterior and lateral continuous fluoroscopy, and cone beam computed tomography (CT). A scaffold tower (L: 300 cm×W: 200 cm×H: 150 cm) was built with radiation-resistant paper cylinders at intervals of 50 cm and plastic joints over the bed, and 100 optically stimulated luminescence dosimeters (nanoDot; Nagase Landauer) were placed on each joint. A human torso phantom from head to pelvis (Kyoto Kagaku) was positioned on the bed in a prone position. The scatter radiation dose in a lateral view was highest on the X-ray tube side at the height of 100 cm (170.5 μGy/min). The scatter radiation dose increased significantly on the X-ray tube side during lateral continuous fluoroscopy. Continuous change of surgeons' standing positions is important to minimize radiation exposure received by a specific surgeon.

Conventional Versus Stereotactic Image-guided Pedicle Screw Placement During Posterior Lumbar Fusions: A Retrospective Propensity Score-matched Study of a National Longitudinal Database

STUDY DESIGN

Retrospective 1:1 propensity score-matched analysis on a national longitudinal database between 2007 and 2016.

OBJECTIVE

The aim of this study was to compare complication rates, revision rates, and payment differences between navigated and conventional posterior lumbar fusion (PLF) procedures with instrumentation.

SUMMARY OF BACKGROUND DATA

Stereotactic navigation techniques for spinal instrumentation have been widely demonstrated to improve screw placement accuracies and decrease perforation rates when compared to conventional fluoroscopic and free-hand techniques. However, the clinical utility of navigation for instrumented PLF remains controversial.

METHODS

Patients who underwent elective laminectomy and instrumented PLF were stratified into "single level" and "3- to 6-level" cohorts. Navigation and conventional groups within each cohort were balanced using 1:1 propensity score matching, resulting in 1786 navigated and conventional patients in the single-level cohort and 2060 in the 3 to 6 level cohort. Outcomes were compared using bivariate analysis.

RESULTS

For the single-level cohort, there were no significant differences in rates of complications, readmissions, revisions, and length of stay between the navigation and conventional groups. For the 3- to 6-level cohort, length of stay was significantly longer in the navigation group (P < 0.0001). Rates of readmissions were, however, greater for the conventional group (30-day: P = 0.0239; 90-day: P = 0.0449). Overall complications were also greater for the conventional group (P = 0.0338), whereas revision rate was not significantly different between the 2 groups. Total payments were significantly greater for the navigation group in both the single level and 3- to 6-level cohorts (P < 0.0001).

CONCLUSION

Although use of navigation for 3- to 6-level instrumented PLF was associated with increased length of stay and payments, the concurrent decreased overall complication and readmission rates alluded to its potential clinical utility. However, for single-level instrumented PLF, no differences in outcomes were found between groups, suggesting that the value in navigation may lie in more complex procedures.

LEVEL OF EVIDENCE

3.

The European Robotic Spinal Instrumentation (EUROSPIN) study: protocol for a multicentre prospective observational study of pedicle screw revision surgery after robot-guided, navigated and freehand thoracolumbar spinal fusion

INTRODUCTION

Robotic guidance (RG) and computer-assisted navigation (NV) have seen increased adoption in instrumented spine surgery over the last decade. Although there exists some evidence that these techniques increase radiological pedicle screw accuracy compared with conventional freehand (FH) surgery, this may not directly translate to any tangible clinical benefits, especially considering the relatively high inherent costs. As a non-randomised, expertise-based study, the European Robotic Spinal Instrumentation Study aims to create prospective multicentre evidence on the potential comparative clinical benefits of RG, NV and FH in a real-world setting.

METHODS AND ANALYSIS

Patients are allocated in a non-randomised, non-blinded fashion to the RG, NV or FH arms. Adult patients that are to undergo thoracolumbar pedicle screw instrumentation for degenerative pathologies, infections, vertebral tumours or fractures are considered for inclusion. Deformity correction and surgery at more than five levels represent exclusion criteria. Follow-up takes place at 6 weeks, as well as 12 and 24 months. The primary endpoint is defined as the time to revision surgery for a malpositioned or loosened pedicle screw within the first postoperative year. Secondary endpoints include patient-reported back and leg pain, as well as Oswestry Disability Index and EuroQOL 5-dimension questionnaires. Use of analgesic medication and work status are recorded. The primary analysis, conducted on the 12-month data, is carried out according to the intention-to-treat principle. The primary endpoint is analysed using crude and adjusted Cox proportional hazards models. Patient-reported outcomes are analysed using baseline-adjusted linear mixed models. The study is monitored according to a prespecified monitoring plan.

ETHICS AND DISSEMINATION

The study protocol is approved by the appropriate national and local authorities. Written informed consent is obtained from all participants. The final results will be published in an international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Clinical Trials.gov registry NCT03398915; Pre-results, recruiting stage.

Robotics in spinal surgery

Although the da Vinci robot system has garnered much attention in the realm of surgery over the past few decades, several new surgical robotic systems have been developed for spinal surgery with varying levels of robot autonomy and surgeon-specified input. These devices are currently being considered as potential avenues for increasing the precision of any surgical intervention. The following review will attempt to provide an overview of robotics in modern spine surgery and how these devices will continue to be employed in various sectors across the field.

Intraoperative Image-Guided Navigation in Craniofacial Surgery: Review and Grading of the Current Literature

INTRODUCTION

Image-guided navigation has existed for nearly 3 decades, but its adoption to craniofacial surgery has been slow. A systematic review of the literature was performed to assess the current status of navigation in craniofacial surgery.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) systematic review of the Medline and Web of Science databases was performed using a series of search terms related to Image-Guided Navigation and Craniofacial Surgery. Titles were then filtered for relevance and abstracts were reviewed for content. Single case reports were excluded as were animal, cadaver, and virtual data. Studies were categorized based on the type of study performed and graded using the Jadad scale and the Newcastle-Ottawa scales, when appropriate.

RESULTS

A total of 2030 titles were returned by our search criteria. Of these, 518 abstracts were reviewed, 208 full papers were evaluated, and 104 manuscripts were ultimately included in the study. A single randomized controlled trial was identified (Jadad score 3), and 12 studies were identified as being case control or case cohort studies (Average Newcastle-Ottawa score 6.8) The most common application of intraoperative surgical navigation cited was orbital surgery (n = 36), followed by maxillary surgery (n = 19). Higher quality studies more commonly pertained to the orbit (6/13), and consistently show improved results.

CONCLUSION

Image guided surgical navigation improves outcomes in orbital reconstruction. Although image guided navigation has promise in many aspects of craniofacial surgery, current literature is lacking and future studies addressing this paucity of data are needed before universal adoption can be recommended.

Economic study: an observational analysis of costs and effectiveness of an intraoperative compared with a preoperative image-guided system in spine surgery fixation: analysis of 10 years of experience

BACKGROUND

Image-guided navigation systems are well establish technologies; their use in clinical practice is growing. To date many publications have demonstrated their accuracy and safety. However, the acquisition and maintenance costs are high. In an era in which health expenditures are rising exponentially, analyses of the economic impact of new technologies are mandatory to assess their sustainability.

METHODS

A retrospective analysis to assess the overall costs of a series of patients admitted to our Neurosurgical Department for spinal instrumentation. We compared two different types of spinal navigation systems: based on preoperative CT scan (January 2003-April 2009) and on intraoperative CT-like scan (April 2009-March 2013). We used a micro-costing approach by a hospital perspective considering all the phases of the treatment process, from pre admission testing to discharge.

RESULTS

The study includes 875 patients. Baseline data, hospitalization and complications were similar for both. Mean cost was 7,305.9 € for intraoperative CT scan procedure and 7,666.2 € for preoperative image-guided system. The effectiveness, in terms of screw accuracy was similar. Higher costs were related to implanted materials, human resources, and disposable.

CONCLUSIONS

There was a statistically significant difference between the two groups in terms of costs. A break-even point for the acquisition of an intraoperative image system is calculated in almost 130 procedures. Moreover, nowadays this system is used for more than only screw insertion reducing the financial impact of this technology on a Hospital.

Computer Navigation for Pediatric Femoral ACL Tunnel Placement

BACKGROUND

To compare accuracy, time and radiation exposure of pediatric femoral tunnel placement using computer navigation with a traditional freehand technique.

METHODS

A single all-epiphyseal femoral tunnel was placed in the distal femur of 20 Sawbones™ adolescent knee models. Ten tunnels were drilled using standard fluoroscopic guidance (FG). An additional 10 tunnels were drilled using 3D fluoroscopic computer navigation (CN). Both techniques aimed to match an exact point described by the quadrant system of Bernard. Time to perform the procedure was recorded as were number of single shot fluoroscopic images and approximate effective radiation doses.

RESULTS

The deviation from ideal femoral tunnel position was on average 6.4 ± 4.2 mm for FG tunnels and 2.7 ± 3.1 mm for CN tunnels (p<0.05) . There was no violation of the femoral growth plate using either technique. The surgeon was exposed to 17 ± 5.3 and 3 ± 0.66 single fluoroscopy exposures for FG and CN guidance, respectively (p<0.05). However, the effective dose for the CN because of the acquisition of 3D images was 0.52±.003 mSv and for FG was only 0.09mSv ± .027 (p <0.001). CN however required on average 12.5 ± 3.4 min compared to 4.6 ± 1.7 for FG (p<0.05) to complete drilling of the tunnel.

CONCLUSON

CN achieves a more accurate epiphyseal femoral ACL tunnel position but requires more time to complete and has a higher effective radiation dose than FG. Whether the CN ACL tunnels can translate to improved clinical outcomes is still unknown.Level of Evidence: V.

Accuracy and revision rate of intraoperative computed tomography point-to-point navigation for lateral mass and pedicle screw placement: 11-year single-center experience in 1054 patients

High accuracy in intraoperative computed tomography (iCT) navigation utilizing an intraoperatively acquired dataset for screw placement in the spine has been reported in the literature. To further improve the accuracy and counteract any intraoperative movement of predefined registration points, we introduce an iCT point-to-point navigation, where marker screws are inserted intraoperatively to increase patient safety. In all, 1054 patients who underwent iCT point-to-point navigation for lateral mass and pedicle screw placement were retrospectively analyzed between 09/2005 and 09/2016. Implant-related complications such as screw misplacement, screw loosening, and revision rate were determined. Furthermore, we investigated the rate of complications and the clinical outcome. In total, 6059 screws were inserted in 1054 patients. There were 553 (52.5%) female and 501 (47.5%) male patients. Average age was 63.5 years, mean BMI 27.5 (SD 13.9). Here, 1427 (23.5%) screws were inserted in the cervical, 995 (16.4%) in the thoracic, 3167 (52.3%) in the lumbar, and 470 (7.8%) in the sacral spine. Eight patients required a revision procedure for screw misplacement (0.8%). Total screw misplacement rate was 0.3% (16/6059). With the use of reference markers in iCT-based, spinal, point-to-point navigation, we achieved a high accuracy of screw placement with a low revision rate (0.8%) and a total screw misplacement rate of 0.3%.

Comparison of the Clinical Accuracy Between Point-to-Point Registration and Auto-Registration Using an Active Infrared Navigation System

STUDY DESIGN

A model experiment.

OBJECTIVE

To measure and compare the clinical accuracy of point-to-point registration (PR) and auto-registration (AR) in an operative set using an active infrared navigation system.

SUMMARY OF BACKGROUND DATA

PR and AR are two major registration methods of navigation assisted spinal surgery. No previous study compared the difference between the two methods with respect to clinical accuracy.

METHODS

A novel method was used to measure the clinical accuracy of the navigation system under an operative set using a Sawbone model with titanium beads on the surface, which was essential to measure the accuracy numerically, instead of a real patient. Both the operative set and the procedure mimicked a regular surgery. The clinical accuracy was defined as the average distance between the "navigation coordinate" and the "image coordinate." The clinical accuracy of the PR using preoperative computed tomography (CT) images and the AR using intraoperative CT images was measured and compared.

RESULTS

The average clinical accuracy of PR was different among different segments. The accuracy of the most accurate segment, which provided the reference points during the PR, was 1.10 mm. In the two segments adjacent to the reference segment, the clinical accuracy deteriorated to 1.37 and 1.50 mm. The accuracy of the farther segments was worse. In comparison, the clinical accuracy of different segments of AR was of no significant difference. The average accuracy of AR was 0.74 mm, which was significantly better than the best accuracy of PR.

CONCLUSION

AR is better than PR with respect to clinical accuracy in navigation assisted spinal surgery.

LEVEL OF EVIDENCE

N/A.

High Speed, High Density Intraoperative 3D Optical Topographical Imaging with Efficient Registration to MRI and CT for Craniospinal Surgical Navigation

Intraoperative image-guided surgical navigation for craniospinal procedures has significantly improved accuracy by providing an avenue for the surgeon to visualize underlying internal structures corresponding to the exposed surface anatomy. Despite the obvious benefits of surgical navigation, surgeon adoption remains relatively low due to long setup and registration times, steep learning curves, and workflow disruptions. We introduce an experimental navigation system utilizing optical topographical imaging (OTI) to acquire the 3D surface anatomy of the surgical cavity, enabling visualization of internal structures relative to exposed surface anatomy from registered preoperative images. Our OTI approach includes near instantaneous and accurate optical measurement of >250,000 surface points, computed at >52,000 points-per-second for considerably faster patient registration than commercially available benchmark systems without compromising spatial accuracy. Our experience of 171 human craniospinal surgical procedures, demonstrated significant workflow improvement (41 s vs. 258 s and 794 s, p < 0.05) relative to benchmark navigation systems without compromising surgical accuracy. Our advancements provide the cornerstone for widespread adoption of image guidance technologies for faster and safer surgeries without intraoperative CT or MRI scans. This work represents a major workflow improvement for navigated craniospinal procedures with possible extension to other image-guided applications.