Operative time and learning curve between fluoroscopy-based instrument tracking and robot-assisted instrumentation for patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF)

Learning curve analyses in spine surgery: a systematic simulation-based critique of methodologies

BACKGROUND CONTEXT

Various statistical approaches exist to delineate learning curves in spine surgery. Techniques range from dividing cases into intervals for metric comparison, to employing regression and cumulative summation (CUSUM) analyses. However, their inherent inconsistencies and methodological flaws limit their comparability and reliability.

PURPOSE

To critically evaluate the methodologies used in existing literature for studying learning curves in spine surgery and to provide recommendations for future research.

STUDY DESIGN

Systematic literature review.

METHODS

A comprehensive literature search was conducted using PubMed, Embase, and Scopus databases, covering articles from January 2010 to September 2023. For inclusion, articles had to evaluate the change in a metric of performance during human spine surgery across time/a case series. Results had to be reported in sufficient detail to allow for evaluation of individual performance rather than group/institutional performance. Articles were excluded if they included cadaveric/nonhuman subjects, aggregated performance data or no way to infer change across a number of cases. Risk of bias was assessed using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool. Surgical data were simulated using Python 3 and then examined via multiple commonly used analytic approaches including division into consecutive intervals, regression and CUSUM techniques. Results were qualitatively assessed to determine the effectiveness and limitations of each approach in depicting a learning curve.

RESULTS

About 113 studies met inclusion criteria. The majority of the studies were retrospective and evaluated a single-surgeon's experience. Methods varied considerably, with 66 studies using a single proficiency metric and 47 using more than 1. Operating time was the most commonly used metric. Interval division was the simplest and most commonly used method yet inherent limitations prevent collective synthesis. Regression may accurately describe the learning curve but in practice is hampered by sample size and model choice. CUSUM analyses are of widely varying quality with some being fundamentally flawed and widely misinterpreted however, others provide a reliable view of the learning process.

CONCLUSION

There is considerable variation in the quality of existing studies on learning curves in spine surgery. CUSUM analyses, when correctly applied, offer the most reliable estimates. To improve the validity and comparability of future studies, adherence to methodological guidelines is crucial. Multiple or composite performance metrics are necessary for a holistic understanding of the learning process.

Comparison of robot-assisted versus fluoroscopy-guided transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative diseases: a systematic review and meta-analysis of randomized controlled trails and cohort studies

BACKGROUND

As an emerging technology in robot-assisted (RA) surgery, the potential benefits of its application in transforaminal lumbar interbody fusion (TLIF) lack substantial support from current evidence.

OBJECTIVE

We aimed to investigate whether the RA TLIF is superior to FG TLIF in the treatment of lumbar degenerative disease.

METHODS

We systematically reviewed studies comparing RA versus FG TLIF for lumbar degenerative diseases through July 2022 by searching PubMed, Embase, Web of Science, CINAHL (EBSCO), Chinese National Knowledge Infrastructure (CNKI), WanFang, VIP, and the Cochrane Library, as well as the references of published review articles. Both cohort studies (CSs) and randomized controlled trials (RCTs) were included. Evaluation criteria included the accuracy of percutaneous pedicle screw placement, proximal facet joint violation (FJV), radiation exposure, duration of surgery, estimated blood loss (EBL), and surgical revision. Methodological quality was assessed using the Cochrane risk of bias and ROBINS-I Tool. Random-effects models were used, and the standardized mean difference (SMD) was employed as the effect measure. We conducted subgroup analyses based on surgical type, the specific robot system used, and the study design. Two investigators independently screened abstracts and full-text articles, and the certainty of evidence was graded using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach.

RESULTS

Our search identified 539 articles, of which 21 met the inclusion criteria for quantitative analysis. Meta-analysis revealed that RA had 1.03-folds higher "clinically acceptable" accuracy than FG (RR: 1.0382, 95% CI: 1.0273-1.0493). And RA had 1.12-folds higher "perfect" accuracy than FG group (RR: 1.1167, 95% CI: 1.0726-1.1626). In the case of proximal FJV, our results indicate a 74% reduction in occurrences for patients undergoing RA pedicle screw placement compared to those in the FG group (RR: 0.2606, 95%CI: 0.2063- 0.3293). Seventeen CSs and two RCTs reported the duration of time. The results of CSs suggest that there is no significant difference between RA and FG group (SMD: 0.1111, 95%CI: -0.391-0.6131), but the results of RCTs suggest that the patients who underwent RA-TLIF need more surgery time than FG (SMD: 3.7213, 95%CI: 3.0756-4.3669). Sixteen CSs and two RCTs reported the EBL. The results suggest that the patients who underwent RA pedicle screw placement had fewer EBL than FG group (CSs: SMD: -1.9151, 95%CI: -3.1265-0.7036, RCTs: SMD: -5.9010, 95%CI: -8.7238-3.0782). For radiation exposure, the results of CSs suggest that there is no significant difference in radiation time between RA and FG group (SMD: -0.5256, 95%CI: -1.4357-0.3845), but the patients who underwent RA pedicle screw placement had fewer radiation dose than FG group (SMD: -2.2682, 95%CI: -3.1953-1.3411). And four CSs and one RCT reported the number of revision case. The results of CSs suggest that there is no significant difference in the number of revision case between RA and FG group (RR: 0.4087,95% CI 0.1592-1.0495). Our findings are limited by the residual heterogeneity of the included studies, which may limit the interpretation of the results.

CONCLUSION

In TLIF, RA technology exhibits enhanced precision in pedicle screw placement when compared to FG methods. This accuracy contributes to advantages such as the protection of adjacent facet joints and reductions in intraoperative radiation dosage and blood loss. However, the longer preoperative preparation time associated with RA procedures results in comparable surgical duration and radiation time to FG techniques. Presently, FG screw placement remains the predominant approach, with clinical surgeons possessing greater proficiency in its application. Consequently, the integration of RA into TLIF surgery may not be considered the optimal choice.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023441600.

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.

Proficiency Development and Learning Curve in Robot-Assisted Spine Surgery Using the ExcelsiusGPS® System: Experience From a Single Institution

STUDY DESIGN

Retrospective Cohort Study Objectives: Robot-assisted spine surgery (RASS) is a rapidly evolving technique with potential benefits for improving surgical outcomes. A number of studies on RASS learning curve have focused on early iterations of the Mazor robot. Limited research exists on the learning curve associated with using the Globus Medical ExcelsiusGPS® system. In this retrospective study, we aimed to evaluate the learning curve of RASS using the ExcelsiusGPS® system at a single institution.

METHODS

A total of 95 patients (541 screws) who underwent RASS between 2021 and 2022 were included. Variables including operative time, robot registration time, screw placement time, fluoroscopy utilization, and complications were analyzed. Statistical analysis was performed using descriptive statistics and two-sample t-tests.

RESULTS

The average operative time significantly decreased after the first 14 cases, indicating a learning curve. However, no significant improvement was observed in robot registration time. Notably, screw placement time significantly improved after approximately 13 cases. When controlling for the number of levels fused, the trends remained consistent.

CONCLUSIONS

Our study confirmed the presence of a learning curve in RASS using the ExcelsiusGPS® system and demonstrated rapid proficiency development. Our findings highlight the relatively quick learning curve of 1 RASS system.

Effectiveness and safety of robot-assisted minimally invasive transforaminal lumbar interbody fusion for degenerative lumbar spinal diseases: a systematic review and meta-analysis

Robot-assisted (RA) technology has been widely used in spine surgery. This analysis aimed to compare the effectiveness and safety of RA minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and fluoroscopy-assisted (FA) MIS-TLIF for degenerative lumbar spinal diseases (DLSD). PubMed, Web of Science, Cochrane Library, and China National Knowledge Infrastructure were systematically searched, and the outcomes included surgical parameters [operation time, blood loss, number of fluoroscopic, accuracy of pedicle screw position, superior facet joint violation (FJV)], and clinical indexes (Visual Analog Scale (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) score, clinical efficacy, hospital stays, complications). Eleven articles involving 1066 patients were included. RA group produced better results than the FA group in operation time (WMD = - 6.59; 95% CI - 12.79 to - 0.40; P = 0.04), blood loss (WMD = - 34.81; 95% CI - 50.55 to - 19.08; P < 0.0001), number of fluoroscopic (WMD = - 18.24; 95% CI - 30.63 to - 5.85; P = 0.004), accuracy of pedicle screw position: Grade A (OR = 3.16; 95% CI 2.36-4.23; P < 0.00001), Grade B (OR = 0.39; 95% CI 0.28-0.54; P < 0.00001), Grade C (OR = 0.27; 95% CI 0.13-0.54; P = 0.0002), and Grade D (OR = 0.17; 95% CI 0.03-0.98; P = 0.05), FJV: Grade 0 (OR = 3.27; 95% CI 1.34-8.02; P = 0.010), Grade 1 (OR = 0.24; 95% CI 0.16-0.38; P < 0.00001), Grade 2 (OR = 0.24; 95% CI 0.12-0.51; P = 0.0002), and Grade 3 (OR = 0.26; 95% CI 0.07-0.93; P = 0.04). But no significant differences in VAS score, ODI, JOA score, clinical efficacy, hospital stays, and complications. These results demonstrate a significant improvement in the intraoperative course of the RA technique. However, RA-MIS-TLIF has not yet demonstrated significant advantages in terms of postoperative symptom relief and functional improvement. Future research and clinical practice should further explore the efficacy of this technique to optimize outcomes and quality of life for patients with DLSD. The study was registered in the PROSPERO (CRD42023454405).

Evaluation of learning curve with Indocyanine Green (IcG) versus blue dye for sentinel lymph node biopsy in breast cancer

BACKGROUND

Indocyanine green (IcG) is an alternative to isosulfan blue (IB) for sentinel lymph node (SLN) mapping in breast cancer (BC). IcG carries improved cost and safety, but oncologic data upon implementation in practice is limited. We evaluated the learning curve defined as oncologic yield and operative (OR) time for IcG in SLN mapping in BC.

METHODS

Retrospective review of patients >18 years with cTis-2 cN0 BC undergoing surgery first with SLN biopsy using IB or IcG. Analysis compared IB versus IcG across three time cohorts.

RESULTS

Of 278 patients, 77 received IB and 201 received IcG. OR time was longer for IcG (p ​= ​0.022). There was no difference in oncologic yield between groups (p ​= ​0.35, p ​= ​0.61).

CONCLUSIONS

Surgeons may be able to safely transition from IB to IcG for patients with early-stage breast cancer undergoing surgery first. Individuals should track their own data to confirm safety of the technique.

Improving Surgeon Well-Being: Ergonomics in Neurosurgery

BACKGROUND

Musculoskeletal disorders are common among surgeons, and affect most neurosurgeons over the course of their career. Although all subspecialist neurosurgeons may be affected by physical strain, spine surgeons and skull base surgeons have a high propensity for workplace injury as a result of long procedures with repetitive movements in strained physical positions.

METHODS

In this review, the prevalence of musculoskeletal disorders in neurosurgery, the state of innovation to improve ergonomics in the operating room for neurosurgeons, and potential limitations in advancing technology with the goal of maximizing neurosurgeon longevity are discussed.

RESULTS

Innovations such as robotics, the exoscope, and handheld devices with more degrees of freedom have allowed surgeons to maneuver instruments without exerting excessive effort, all while maintaining neutral body positioning, avoiding joint and muscle strain.

CONCLUSIONS

As new technology and innovation in the operating room develop, there has been a larger emphasis placed on maximizing surgeon comfort and neutral positioning, by minimizing force exertion and fatigue.

Opportunities and challenges for robotic-assisted spine surgery: feasible indications for the MAZOR™ X Stealth Edition

The clinical use of new technologies has several potential benefits including improved accuracy, precision and efficiency. Robotic assistance during surgery is one such technology and it is making its way into neurosurgical operating rooms with increasing frequency. The Mazor X™ Stealth robot was first used in Canada for spine surgery during July 2022 and since then multiple indications for its use have been identified and evaluated.The outcomes of robot-assisted spine surgery have been promising but there is a lack of supportive studies which would serve to refine indications, establish protocols and disseminate practical information. To begin filling this gap we gathered a list of use-cases for which this new technology was successfully employed. In combination with cases that took place in our Centre, we reviewed the existing reported uses of the Mazor X™ Stealth for spine surgery and recorded their respective procedures and outcomes for patients and surgeons.Through this review we identified common uses of the Mazor X™ Stealth for spine surgery. Usage of robotic-assisted technology had a net positive impact on outcomes for patients as well as surgeons (e.g., improved accuracy of pedicle screw placement and reduced radiation burden). This curation remains a dynamic list, and we foresee the addition of more indications in the future.Clinical Relevance- Enabling the use of technology including robotic systems has the potential to attract clinical research expertise, reduce resource usage and to improve surgical outcomes.

Spinal Fusion Versus Repeat Discectomy for Recurrent Lumbar Disc Herniation: A Systematic Review and Meta-Analysis

OBJECTIVE

Recurrent lumbar disc herniation (RLDH) is one of the major causes of failure for primary surgery. Repeat discectomy (RD) and spinal fusion (SF) are 2 surgical options for RLDH. The objective of our study is to compare the effectiveness of SF compared with RD in the treatment of RLDH.

METHODS

We systematically searched PubMed, Embase, Cochrane Library, Web of Science, and Ovid Medline for studies (published between Jan 1, 1959 and July 8, 2022; no language restriction) comparing SF and RD for the RLDH. Odds ratio and weighted mean difference were calculated for binary outcomes and continuous outcomes. The quality of each outcome was graded using the Grading of Recommendations, Assessment, Development and Evaluations criteria.

RESULTS

We identified 5029 studies, of which 11 studies were included. There were 2 randomized controlled trials and the remaining were observational studies. Comparing SF and RD groups, no differences were found in visual analog scales for leg and back and Oswestry Disability Index. Furthermore, the Japanese Orthopaedic Association scores of SF were significantly higher than the RD group. In terms of complications, the incidence of neurological deficit, segmental instability, and re-recurrence is significantly lower with SF than with the RD group. Lastly, the SF group was associated with longer hospital stays and operation time, and more blood loss.

CONCLUSIONS

The pooled evidence suggests that fusion achieves better results than RD for RLDH. The results of this review should be further confirmed by future high-quality randomized controlled trials.

A Comparison of Percutaneous Pedicle Screw Accuracy Between Robotic Navigation and Novel Fluoroscopy-Based Instrument Tracking for Patients Undergoing Instrumented Thoracolumbar Surgery

BACKGROUND

The accuracy of pedicle screws placed with instrument tracking and robotic navigation are individually comparable or superior to placement using standard fluoroscopy, however head-to-head comparisons between these adjuncts in a similar surgical population have yet to be performed.

METHODS

Consecutive patients undergoing percutaneous thoracic and lumbosacral spinal instrumentation were retrospectively enrolled. Instrumentation was performed using either fluoroscopy-based instrument tracking system (TrackX, TrackX Technologies) or robotic-navigation (ExcelsiusGPS, Globus Medical). Postinstrumentation computed tomography scans were graded for breach according to the Gertzbein-Robbins scale, with "acceptable" screws deemed as Grade A or B and "unacceptable" screws deemed as Grades C through E. Accuracy data was compared between both instrumentation modalities.

RESULTS

Fifty-three patients, comprising a total of 250 screws (167 robot, 83 instrument tracking) were included. The overall accuracy between both modalities was similar, with 96.4% and 97.6% of screws with acceptable accuracy between instrument tracking and robotic navigation, respectively (I-squared 0.30, df = 1, P = 0.58). Between instrument tracking and robotic navigation, 92.8% and 95.8% of screws received Grade A, 3.6% and 1.8% a Grade B, 1.2% and 1.2% a Grade C, 1.2% and 0.6% a Grade D, and 1.2% and 0.6% a Grade E, respectively. The robot was abandoned intraoperatively in 2 cases due to unrecoverable registration inaccuracy or software failure, leading to abandonment of 8 potential screws (4.8%).

CONCLUSIONS

In a similar patient population, there is a similarly high degree of instrumentation accuracy between fluoroscopy-based instrument tracking and robotic navigation. There is a rare chance for screw breach with either surgical adjunct.

Robotics in spine surgery: systematic review of literature

PURPOSE

Over 4.83 million spine surgery procedures are performed annually around the world. With the considerable caseload and the precision needed to achieve optimal spinal instrumentation, technical progress has helped to improve the technique's safety and accuracy with the development of peri-operative assistance tools. Contrary to other surgical applications already part of the standard of care, the development of robotics in spine surgery is still a novelty and is not widely available nor used. Robotics, especially when coupled with other guidance modalities such as navigation, seems to be a promising tool in our quest for accuracy, improving patient outcomes and reducing surgical complications. Robotics in spine surgery may also be for the surgeon a way to progress in terms of ergonomics, but also to respond to a growing concern among surgical teams to reduce radiation exposure.

METHOD

We present in this recent systematic review of the literature realized according to the PRISMA guidelines the place of robotics in spine surgery, reviewing the comparison to standard techniques, the current and future indications, the learning curve, the impact on radiation exposure, and the cost-effectiveness.

RESULTS

Seventy-six relevant original studies were identified and analyzed for the review.

CONCLUSION

Robotics has proved to be a safe help for spine surgery, both for the patient with a decrease of operating time and increase in pedicular screw accuracy, and for the surgical team with a decrease of radiation exposure. Medico-economic studies demonstrated that despite a high buying cost, the purchase of a robot dedicated for spine surgery is cost-effective resulting in lesser revision, lower infection, reduced length of stay, and shorter surgical procedure.

Learning curves in robotic neurosurgery: a systematic review

The transition to performing procedures robotically generally entails a period of adjustment known as a learning curve as the surgeon develops a familiarity with the technology. However, no study has comprehensively examined robotic learning curves across the field of neurosurgery. We conducted a systematic review to characterize the scope of literature on robotic learning curves in neurosurgery, assess operative parameters that may involve a learning curve, and delineate areas for future investigation. PubMed, Embase, and Scopus were searched. Following deduplication, articles were screened by title and abstract for relevance. Remaining articles were screened via full text for final inclusion. Bibliographic and learning curve data were extracted. Of 746 resultant articles, 32 articles describing 3074 patients were included, of which 23 (71.9%) examined spine, 4 (12.5%) pediatric, 4 (12.5%) functional, and 1 (3.1%) general neurosurgery. The parameters assessed for learning curves were heterogeneous. In total, 8 (57.1%) of 14 studies found reduced operative time with increased cases, while the remainder demonstrated no learning curve. Six (60.0%) of 10 studies reported reduced operative time per component with increased cases, while the remainder indicated no learning curve. Radiation time, radiation time per component, robot time, registration time, setup time, and radiation dose were assessed by ≤ 4 studies each, with 0-66.7% of studies demonstrated a learning curve. Four (44.4%) of 9 studies on accuracy showed improvement over time, while the others indicated no improvement over time. The number of cases required to reverse the learning curve ranged from 3 to 75. Learning curves are common in robotic neurosurgery. However, existing studies demonstrate high heterogeneity in assessed parameters and the number of cases that comprise the learning curve. Future studies should seek to develop strategies to reduce the number of cases required to reach the learning curve.

Prone Transpsoas Lateral Lumbar Interbody Fusion for Degenerative Lumbar Spine Disease: Case Series With an Operative Video Using Fluoroscopy-Based Instrument Tracking Guidance

BACKGROUND

Lateral lumbar interbody fusion has inherent limitations, such as the necessity to reposition the patient. To overcome this limitation, the prone transpsoas (PTP) approach for lateral lumbar interbody fusion has been developed.

OBJECTIVE

To report clinical and radiographic outcome measures of a series of patients who underwent PTP at our hospital.

METHODS

A retrospective chart review was conducted to identify patients who underwent PTP for degenerative lumbar spine disease between September 2019 and August 2021. A thorough analysis of clinical and radiographic outcome measures for these patients was conducted.

RESULTS

Our search resulted in the identification of 15 consecutive patients. Four patients were operated using the assistance of fluoroscopy-based instrument tracking. Overall, the mean follow-up duration was 11.9 ± 7.9 months. Radiographically, the PTP approach resulted in significant postoperative improvement of lumbar lordosis ( P = .03) and pelvic incidence minus lumbar lordosis ( P &lt; .005). No significant difference was found postoperatively in other regional sagittal alignment parameters, including pelvic tilt, sacral slope, or pelvic incidence. Clinically, the patients' Oswestry Disability Indices ( P = .002) and Short Form Survey-12 Physical Scores improved significantly ( P = .01). The estimated mean blood loss for patients who underwent the PTP procedure was 137.7 ± 96.4 mL, the mean operative time was 212.5 ± 77.1 minutes, and the mean hospital stay was 2.7 ± 1.4 days. One patient each had superficial wound infection, transient paralytic ileus, transient pulmonary embolism, transient urinary retention, or required revision lumbar surgery.

CONCLUSION

This study demonstrates that the PTP approach is associated with significant improvement in radiographic and clinical outcomes.

Application and thinking of minimally invasive transforaminal lumbar interbody fusion in degenerative lumbar diseases

Background

This study sought to investigate the clinical efficacy and safety of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of lumbar degenerative diseases.

Methods

The clinical data of 55 patients with lumbar degenerative diseases treated at our hospital from January 2018 to January 2020 were analyzed retrospectively. Of the 55 patients, 35 who underwent MIS-TLIF were included in the MIS-TLIF group, and 20 who underwent posterior lumbar interbody fusion (PLIF) were included in the PLIF group. The visual analogue scale (VAS) score, Oswestry disability index (ODI) score, operation time, incision length, intraoperative bleeding, postoperative drainage, postoperative landing time, postoperative hospital stay, postoperative interbody fusion rate, and complications were compared between the two groups.

Results

The patients in both groups were followed-up for at least 1.5 years (range, 18–30 months; with an average of 27.5±2.6 months). There was no significant difference in the operation time, incision length, intraoperative bleeding, VAS score for low back and leg pain, ODI score, interbody fusion rate, hospitalization expenses, and complication rate between the two groups (P>0.05). One patient had nail failure in the MIS-TLIF group, 1 patient in each group had nerve root irritation, and 1 patient in each group had superficial incision infection and local suture dehiscence. The postoperative drainage volume, postoperative landing time, and postoperative hospital stay of the MIS-TLIF group were less than those of the PLIF group (P<0.05).

Conclusions

Compared to PLIF, the use of MIS-TLIF in the treatment of lumbar degenerative diseases has a number of advantages, including more complete intraoperative hemostasis, less postoperative drainage, earlier landing, and faster discharge, and also significantly improves postoperative lumbar discomfort.

Learning curves in robot-assisted spine surgery: a systematic review and proposal of application to residency curricula

OBJECTIVE

Spine robots have seen increased utilization over the past half decade with the introduction of multiple new systems. Market research expects this expansion to continue over the next half decade at an annual rate of 20%. However, because of the novelty of these devices, there is limited literature on their learning curves and how they should be integrated into residency curricula. With the present review, the authors aimed to address these two points.

METHODS

A systematic review of the published English-language literature on PubMed, Ovid, Scopus, and Web of Science was conducted to identify studies describing the learning curve in spine robotics. Included articles described clinical results in patients using one of the following endpoints: operative time, screw placement time, fluoroscopy usage, and instrumentation accuracy. Systems examined included the Mazor series, the ExcelsiusGPS, and the TiRobot. Learning curves were reported in a qualitative synthesis, given as the mean improvement in the endpoint per case performed or screw placed where possible. All studies were level IV case series with a high risk of reporting bias.

RESULTS

Of 1579 unique articles, 97 underwent full-text review and 21 met the inclusion and exclusion criteria; 62 articles were excluded for not presenting primary data for one of the above-described endpoints. Of the 21 articles, 18 noted the presence of a learning curve in spine robots, which ranged from 3 to 30 cases or 15 to 62 screws. Only 12 articles performed regressions of one of the endpoints (most commonly operative time) as a function of screws placed or cases performed. Among these, increasing experience was associated with a 0.24- to 4.6-minute decrease in operative time per case performed. All but one series described the experience of attending surgeons, not residents.

CONCLUSIONS

Most studies of learning curves with spine robots have found them to be present, with the most common threshold being 20 to 30 cases performed. Unfortunately, all available evidence is level IV data, limited to case series. Given the ability of residency to allow trainees to safely perform these cases under the supervision of experienced senior surgeons, it is argued that a curriculum should be developed for senior-level residents specializing in spine comprising a minimum of 30 performed cases.