Three-Dimensional Printing for Preoperative Planning and Pedicle Screw Placement in Adult Spinal Deformity: A Systematic Review

A novel guide device for pedicle screw insertion using three-dimensional preoperative planning in open lumbar spinal surgery: a comparative retrospective study

OBJECTIVE

Pedicle screw stabilization (PSS) surgeries for spinal instability are still the most effective treatment approach. The use of preoperative planning can minimize the complications related to transpedicular screw (TPS) misplacement. The study aimed to evaluate the surgical outcomes of a guide device developed to improve the accuracy of the free-hand technique using three-dimensional planning in PSS.

PATIENTS AND METHODS

Patients with degenerative spinal diseases who underwent open PSS between 2019 and 2022 were evaluated retrospectively. FG group included patients who were operated on using the fluoroscopy alone with preoperative two-dimensional planning. AFG group included patients who were operated on using a guide advice-assisted technique with preoperative 3DP. Between-group comparisons were performed.

RESULTS

A total of 143 patients with a mean age of 59.6 years were included in the study. 71 patients were assessed in the FG group and 72 patients in the AFG group. Between-group comparisons regarding demographics, etiologies, radiation exposure, and functional improvements showed no significant differences (p > 0.05). Although the accuracy of TPSs positioning was 94.2% and 96.5% in the 2DG and 3DG, the difference between the groups was not statistically significant. The statistically significant differences regarding the upper-level facet joint violation and pedicle breach rates were lower in the AFG group (p < 0.0001; X2 = 19.57) and (p < 0.0001; X2 = 25.3), respectively.

CONCLUSION

Using a guide device associated with preoperative 3PD reduced the upper-level facet joint violation and pedicle breach rates in open PSS surgeries performed by free-hand technique for degenerative spinal diseases.

Clinical outcomes of 20 brachycephalic dogs with thoracolumbar spinal deformities causing neurological signs treated with spinal stabilization using 3D-printed patient-specific drill guides

OBJECTIVE

To describe the clinical outcomes for pugs and French bulldogs with congenital vertebral malformations, undergoing thoracolumbar spinal stabilization surgery using 3D-printed patient-specific drill guides. To evaluate the accuracy of pedicle screw placement in this group of dogs.

STUDY DESIGN

Retrospective descriptive study.

ANIMALS

Twenty dogs (12 pugs and eight French bulldogs).

METHODS

Medical records searched between August 2018 and March 2021 for pugs and French bulldogs diagnosed with congenital vertebral abnormalities via magnetic resonance imaging (MRI) scan and computed tomography (CT) scan causing T3-L3 myelopathy signs that underwent spinal stabilization surgery using 3D-printed patient-specific drill guides followed by a postoperative CT scan. The short-term outcome was based on the neurological grade (modified Frankel score-MFS) on the day after surgery, day of discharge, and at the follow-up examination at 4 to 6 weeks after surgery. The mid-term outcome was obtained via an online questionnaire (or direct examination in one case).

RESULTS

Twenty dogs met the inclusion criteria (19/20 grade 2 MFS, 1/20 grade 4 MFS). No complications were reported in the immediate postoperative period and optimal pedicle screw placement was obtained in 169/201 of screws. Twenty-four hours after surgery 16/20 dogs displayed an unchanged neurological grade. Short-term outcomes revealed a static (17/20) or improved (2/20) neurological grade. Ten owners participated in the online questionnaire. All patients were reported to be ambulatory; however, 7/10 dogs displayed abnormal gait. Neurological signs had remained static (6/10) or improved (3/10) in comparison with the dogs' preoperative status at a median of 883.5 days from the surgery.

CONCLUSION

Dogs in this study had a favorable short-term outcome and mid-term outcome evaluation revealed a static/improved neurological status.

CLINICAL SIGNIFICANCE

Thoracolumbar spinal stabilization surgery using 3D-printed patient-specific drill guides showed a favorable outcome in brachycephalic breeds affected by vertebral deformities.

Preoperative Robotics Planning Facilitates Complex Construct Design in Robot-Assisted Minimally Invasive Adult Spinal Deformity Surgery-A Preliminary Experience

(1) Background: The correction of adult spinal deformity (ASD) can require long, complex constructs with multiple rods which traverse important biomechanical levels to achieve multi-pelvic fixation. Minimally invasive (MIS) placement of these constructs has historically been difficult. Advanced technologies such as spinal robotics platforms can facilitate the design and placement of these constructs and further enable these surgical approaches in MIS deformity surgery. (2) Methods: A retrospective study was performed on a series of ASD patients undergoing MIS deformity correction with ≥eight fusion levels to the lower thoracic spine with preoperative robotic construct planning and robot-assisted pedicle screw placement. (3) Results: There were 12 patients (10 female, mean age 68.6 years) with a diagnosis of either degenerative scoliosis (8 patients) or sagittal imbalance (4 patients). All underwent preoperative robotic planning to assist in MIS robot-assisted percutaneous or transfascial placement of pedicle and iliac screws with multiple-rod constructs. Mean operative values per patient were 9.9 levels instrumented (range 8-11), 3.9 interbody cages (range 2-6), 3.3 iliac fixation points (range 2-4), 3.3 rods (range 2-4), 18.7 screws (range 13-24), estimated blood loss 254 cc (range 150-350 cc), and operative time 347 min (range 242-442 min). All patients showed improvement in radiographic sagittal, and, if applicable, coronal parameters. Mean length of stay was 5.8 days with no ICU admissions. Ten patients ambulated on POD 1 or 2. Of 224 screws placed minimally invasively, four breaches were identified on intraoperative CT and repositioned (three lateral, one medial) for a robot-assisted screw accuracy of 98.2%. (4) Conclusions: Minimally invasive long-segment fixation for adult spinal deformity surgery has historically been considered laborious and technically intensive. Preoperative robotics planning facilitates the design and placement of even complex multi-rod multi-pelvic fixation for MIS deformity surgery.

Three-Dimensional Printing Applications in Pediatric Spinal Surgery: A Systematic Review

STUDY DESIGN

Systematic Review.

OBJECTIVE

3DP technology use has become increasingly more common in the field of medicine and is notable for its growing utility in spine surgery applications. Many studies have evaluated the use of pedicle screw placement guides and spine models in adult spine patients, but there is little evidence assessing its efficacy in pediatric spine patient populations. This systematic review identifies and evaluates the current applications and surgical outcomes of 3-Dimensional Printing (3DP) technology in pediatric spinal surgery.

METHODS

A search of publications was conducted using literature databases and relevant keywords in concordance with PRISMA guidelines. Inclusion criteria consisted of original studies, and studies focusing on the use of 3DP technology in pediatric spinal surgery. Studies with a focus on adult populations, non-deformity surgery, animal subjects, systematic or literature reviews, editorials, or non-English studies were excluded from further analysis.

RESULTS

After application of inclusion/exclusion criteria, we identified 25 studies with 3DP applications in pediatric spinal surgery. Overall, the studies found significantly improved screw placement accuracy using 3DP pedicle screw placement guides but did not identify significant differences in operative time or blood loss. All studies that utilized 3D spine models in preoperative planning found it helpful and noted an increased screw placement accuracy rate of 89.9%.

CONCLUSIONS

3DP applications and techniques are currently used in pre-operative planning using pedicle screw drill guides and spine models to improve patient outcomes in pediatric spinal deformity patients.

Systematic review of the utility and limits of 3D printing in spine surgery

OBJECTIVE

The main objective of this study has been to demonstrate why additive printing allows to make complex surgical pathological processes that affect the spine more visible and understandable, increasing precision, safety and reliability of the surgical procedure.

METHODS

A systematic review of the articles published in the last 10 years on 3D printing-assisted spinal surgery was carried out, in accordance with PRISMA 2020 declaration. Keywords "3D printing" and "spine surgery" were searched in Pubmed, Embase, Cochrane Database of Systematic Reviews, Google Scholar and Opengrey databases, which was completed with a manual search through the list of bibliographic references of the articles that were selected following the defined inclusion and exclusion criteria.

RESULTS

From the analysis of the 38 selected studies, it results that 3D printing is useful in surgical planning, medical teaching, doctor-patient relationship, design of navigation templates and spinal implants, and research, optimizing the surgical process by focusing on the patient, offering magnificent support during the surgical procedure.

CONCLUSIONS

The use of three-dimensional printing biomodels allows: making complex surgical pathological processes that affect the spine more visible and understandable; increase the accuracy, precision and safety of the surgical procedure, and open up the possibility of implementing personalized treatments, mainly in tumor surgery.

Comparing Three-dimensional and Two-dimensional Preoperative Planning for Lumbar Transpedicular Screw Placement: A Retrospective Study

BACKGROUND

 Transpedicular screw (TPS) misplacement is still a nightmare for spine surgeons. Preoperative planning is one of the methods that a surgeon could use to minimize this complication. This study aims to compare the efficacy of three-dimensional (3D) and two-dimensional (2D) preoperative planning in posterior lumbar TPSs placement performed using the freehand technique.

PATIENTS AND METHODS

 Patients who underwent posterior TPSs placement for degenerative lumbar spondylolisthesis or spinal stenosis using the freehand technique between November 2021 and October 2022 were evaluated retrospectively. In total, 33 and 30 patients who met the inclusion criteria were consecutively operated on with preoperative 2D and 3D planning, respectively. The patients were divided into the 2D preoperative planning group (2DG) and 3D preoperative planning group (3DG) and the two groups were compared.

RESULTS

 Sixty-three patients were operated during the study period. There was no significant difference between the groups regarding blood transfusion, operation time, and radiation exposure. Although the accuracy of TPSs positioning was 94.2 and 96.5% in the 2DG and 3DG, respectively, the difference between the groups was not statistically significant. The upper facet joint violation rate was 12.8% (n = 20) in the 2DG versus 3.5% (n = 5) in the 3DG (p = 0.006). All L4 TPSs were inserted with their standard entry points without any modification (p < 0.0001; relative/risk ratio = 0.64). The modification rate was higher in L1, L2, and L5 TPSs (p < 0.0001; χ 2 = 24.7).

CONCLUSION

 For patients with degenerative lumbar diseases, 3D preoperative planning in posterior lumbar instrumentation surgeries performed with the freehand technique decreased the upper facet joint violation rate.

3D printed pedicle screw guides reduce the rate of intraoperative screw revision in adolescent idiopathic scoliosis surgery

BACKGROUND CONTEXT

Pedicle screw fixation has become common in the treatment of adolescent idiopathic scoliosis (AIS). Malpositioned pedicle screws have significant complications and identifying surgical techniques to optimize screw placement accuracy is imperative.

PURPOSE

To compare the rate of intraoperative revision, replacement, or removal of pedicle screws placed utilizing 3D printed guides compared with pedicle screws placed utilizing a freehand technique.

STUDY DESIGN/SETTING

Retrospective cohort study/single academic center.

PATIENT SAMPLE

Thirty-two patients aged 10 to 18 with AIS.

OUTCOME MEASURES

Revision rate of pedicle screws and operative time between groups.

METHODS

A retrospective study was performed on patients 10 to 18 years of age who underwent posterior spinal instrumented fusion for AIS from February 2021 to July 2022. The study received an IRB exemption. Patient demographics, intraoperative measures, and outcome variables were recorded. Intraoperatively, all patients underwent a 3-dimensional fluoroscopic "check scan," which included axial, sagittal, and coronal images, to assess for screw accuracy. A secondary outcome of operative time was compared between groups. The p-values <.05 were considered significant.

RESULTS

A total of 32 patients were included in this study. There were 17 cases in the 3D guided and 15 cases in fluoroscopy-guided freehand cohort. There was a total of 254 pedicle screws using 3D guides and 402 screws using freehand technique. Between cohorts, there were no significant differences in a number of levels fused (p=.54) or length of surgery (p=.36). The total revision rate of 3D guided screw placement was 5.5% and that of the freehand technique was 8.5%. The freehand screw placement group had significantly higher revision rates per vertebral level compared with 3D guided (p=.0096). Notably, 3D printed guides had fewer screws that were removed/revised for being too anterior (7.1%) compared with freehand (23.5%). Surgical time was not significantly different between the 3D guided and freehand cohort (p=.35).

CONCLUSIONS

3D printed guides reduce intraoperative revision rate compared with freehand techniques. Total operative time is comparable to freehand technique.

Optimizing Surgical Performance Using Preoperative Virtual Reality Planning: A Systematic Review

BACKGROUND

Surgery is often a complex process that requires detailed 3-dimensional anatomical knowledge and rigorous interplay between team members to attain ideal operational efficiency or "flow." Virtual Reality (VR) represents a technology by which to rehearse complex plans and communicate precise steps to a surgical team prior to entering the operating room. The objective of this study was to evaluate the use of VR for preoperative surgical team planning and interdisciplinary communication across all surgical specialties.

METHODS

A systematic review of the literature was performed examining existing research on VR use for preoperative surgical team planning and interdisciplinary communication across all surgical fields in order to optimize surgical efficiency. MEDLINE, SCOPUS, CINAHL databases were searched from inception to July 31, 2022 using standardized search clauses. A qualitative data synthesis was performed with particular attention to preoperative planning, surgical efficiency optimization, and interdisciplinary collaboration/communication techniques determined a priori. Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines were followed. All included studies were appraised for their quality using the Medical Education Research Study Quality Instrument (MERSQI) tool.

RESULTS

One thousand and ninety-three non-duplicated articles with abstract and full text availability were identified. Thirteen articles that examined preoperative VR-based planning techniques for optimization of surgical efficiency and/or interdisciplinary communication fulfilled inclusion and exclusion criteria. These studies had a low-to-medium methodological quality with a MERSQI mean score of 10.04 out of 18 (standard deviation 3.61).

CONCLUSIONS

This review demonstrates that time spent rehearsing and visualizing patient-specific anatomical relationships in VR may improve operative efficiency and communication across multiple surgical specialties.

PreOperative Planning for Adult Spinal Deformity Goals: Level Selection and Alignment Goals

Adult Spinal Deformity (ASD) is a complex pathologic condition with significant impact on quality of life, including pain, loss of function, and fatigue. Achieving realignment goals is crucial for long-term results. Reliable preoperative planning strategies, including nomograms, measurement tools, and level selection, are key to maximizing the likelihood of achieving a good outcome following ASD corrective surgery. This review covers recent literature on such strategies, including review of the different targets for realignment and their association with outcomes (both patients-reported outcomes and complications), selection of upper and lower instrumented vertebrae, and the latest innovation in preoperative planning for deformity surgery.

Personalized Medicine in Orthopaedic Surgery: The Case of Spine Surgery

Personalized medicine has made a tremendous impact on patient care. Although initially, it revolutionized pharmaceutical development and targeted therapies in oncology, it has also made an important impact in orthopaedic surgery. The field of spine surgery highlights the effect of personalized medicine because the improved understanding of spinal pathologies and technological innovations has made personalized medicine a key component of patient care. There is evidence for several of these advancements to support their usage in improving patient care. Proper understanding of normative spinal alignment and surgical planning software has enabled surgeons to predict postoperative alignment accurately. Furthermore, 3D printing technologies have demonstrated the ability to improve pedicle screw placement accuracy compared with free-hand techniques. Patient-specific, precontoured rods have shown improved biomechanical properties, which reduces the risk of postoperative rod fractures. Moreover, approaches such as multidisciplinary evaluations tailored to specific patient needs have demonstrated the ability to decrease complications. Personalized medicine has shown the ability to improve care in all phases of surgical management, and several of these approaches are now readily available to orthopaedic surgeons.

3D-Printed Guide Plate System-Assisted Thoracolumbar Kyphosis Osteotomy: A Technical Case Series

OBJECTIVE

This paper reports a new three-dimensional (3D)-printed osteotomy guidance system to assist thoracolumbar kyphosis osteotomy and describe the guide plate design, surgical procedure, and short-term clinical results.

METHODS

The computer-aided design software reconstructs the 3D model of the spinal deformity region using the computed tomography data of the patient and plans the correction angle according to the deformity. The guide plate design described in previous experimental studies was used and optimized before clinical application. The lamina positioning, lamina osteotomy, and vertebral osteotomy guides were designed, and three 3D guides with different functions were used to assist osteotomy.

RESULTS

Seven patients successfully underwent osteotomy under the guidance of a 3D guide plate. Kyphosis was corrected to different degrees without serious complications. At the last follow-up, the back pain and nerve function of 7 patients were improved to varying degrees and the internal fixation without displacement and fracture.

CONCLUSIONS

The preliminary clinical application of the new 3D osteotomy guidance system shows that it provides an effective connection between the guide plates and a clinically operative visual field. The use of a 3D guide plate system for positioning and guidance is helpful to complete preoperative planning of anterior and middle column vertebral body osteotomy. However, the efficacy of this method should be compared to that of the free-hand technique with long-term follow-up.

Clinical Application of Personalized Digital Surgical Planning and Precise Execution for Severe and Complex Adult Spinal Deformity Correction Utilizing 3D Printing Techniques

(1) Background: The three-dimensional printing (3DP) technique has been reported to be of great utility in spine surgery. The purpose of this study is to report the clinical application of personalized preoperative digital planning and a 3DP guidance template in the treatment of severe and complex adult spinal deformity. (2) Methods: eight adult patients with severe rigid kyphoscoliosis were given personalized surgical simulation based on the preoperative radiological data. Guidance templates for screw insertion and osteotomy were designed and manufactured according to the planning protocol and used during the correction surgery. The perioperative, and radiological parameters and complications, including surgery duration, estimated blood loss, pre- and post-operative cobb angle, trunk balance, and precision of osteotomy operation with screw implantation were collected retrospectively and analyzed to evaluate the clinical efficacy and safety of this technique. (3) Results: Of the eight patients, the primary pathology of scoliosis included two adult idiopathic scoliosis (ADIS), four congenital scoliosis (CS), one ankylosing spondylitis (AS), and one tuberculosis (TB). Two patients had a previous history of spinal surgery. Three pedicle subtraction osteotomies (PSOs) and five vertebral column resection (VCR) osteotomies were successfully performed with the application of the guide templates. The main cobb angle was corrected from 99.33° to 34.17°, and the kyphosis was corrected from 110.00° to 42.00°. The ratio of osteotomy execution and simulation was 97.02%. In the cohort, the average screw accuracy was 93.04%. (4) Conclusions: The clinical application of personalized digital surgical planning and precise execution via 3D printing guidance templates in the treatment of severe adult rigid deformity is feasible, effective, and easily generalizable. The preoperative osteotomy simulation was executed with high precision, utilizing personalized designed guidance templates. This technique can be used to reduce the surgical risk and difficulty of screw placement and high-level osteotomy.

Research relating to three-dimensional (3D) printing in spine surgery: a bibliometric analysis

PURPOSE

Although numerous publications on three-dimensional printing (3DP) in spine surgery have been published, bibliometric analysis studies are scarce. Thus, this study aimed to present a bibliometric analysis of the status, hot spots, and frontiers of 3DP in spine surgery and associated research disciplines.

METHODS

All publications relating to the utilization of 3DP in spine surgery from 1999 to May 9, 2022, were retrieved from the Web of Science. The bibliometric analysis was performed using CiteSpace software, and information on the country, institution, author, journal, and keywords for each publication was collected.

RESULTS

A total of 270 articles were identified. From 2016 onward, a significant increase in publications on spinal surgery was observed. China was the most productive and influential country (98 publications) and H-index (22), followed by the USA and Australia. The most productive institution was Capital Medical University (9 publications). P. S. D'urso (8 publications, 46 citations) and R. J. Mobbs (8 publications, 39 citations) were the most prolific authors. European Spine Journal contributed the highest number of publications. The eight main clusters were: "rapid prototyping" #0, "3D printed" #1, "spine fusion" #2, "scoliosis" #3, "spine surgery" #4, "patient-specific" #5, "nervous system" #6, and "neuronavigation" #7. The strongest keyword bursts in 3DP in spine surgery were "fixation," "drill template," "instrumentation," "fusion," "complication," and "atlantoaxial instability."

CONCLUSION

This analysis provides information on research trends and frontiers in the application of 3DP in spine surgery, as well as research and collaboration partners, institutions, and countries.

The application of additive manufacturing technology in pelvic surgery: A bibliometrics analysis

With the development of material science, additive manufacturing technology has been employed for pelvic surgery, addressing the challenges, such as the complex structure of the pelvis, difficulty in exposing the operative area, and poor visibility, of the traditional pelvic surgery. However, only limited studies have been done to review the research hotspots and trends of the additive manufacturing technology applied for pelvic surgery. In this study, we comprehensively analyzed the literatures related to additive manufacturing technology in pelvic surgery by a bibliometrics analysis and found that additive manufacturing technology is widely used in several aspects of preoperative diagnosis, preoperative planning, intraoperative navigation, and personalized implants for pelvic surgery. Firstly, we searched and screened 856 publications from the Web of Science Core Collection (WoSCC) with TS = (3D printing OR 3D printed OR three-dimensional printing OR additive manufacturing OR rapid prototyping) AND TS = (pelvis OR sacrum OR ilium OR pubis OR ischium OR ischia OR acetabulum OR hip) as the search strategy. Then, 565 of these were eliminated by evaluating the titles and abstracts, leaving 291 pieces of research literature whose relevant information was visually displayed using VOSviewer. Furthermore, 10 publications with high citations were selected by reading all publications extensively for carefully evaluating their Titles, Purposes, Results, Limitations, Journal of affiliation, and Citations. Our results of bibliometric analysis demonstrated that additive manufacturing technology is increasingly applied in pelvic surgery, providing readers with a valuable reference for fully comprehending the research hotspots and trends in the application of additive manufacturing technology in pelvic surgery.

Pedicle screw placement safety with the aid of patient-specific guides in a case series of patients with thoracic scoliosis

PURPOSE

Pedicle screw (PS) placement in thoracic scoliotic deformities can be challenging due to altered vertebral anatomy; malposition can result in severe functional disability or inferior construct stability. Three-dimensional (3D) printed patient-specific guides (PSGs) have been recently used to supplement other PS placement techniques. We conducted a single-center, retrospective observational study to assess the accuracy of PS placement using PSGs in a consecutive case series of pediatric and adult patients with thoracic scoliosis.

METHODS

We analyzed the data of patients with thoracic scoliosis who underwent PS placement using 3D-printed PSG as a vertebral cannulation aid between June 2013 and July 2018. PS positions were determined via Gertzbein-Robbins (GR) and Heary classifications on computed tomography images. We determined the concordance of actual and preoperatively planned PS positions and defined the technique learning curve using a receiver-operating characteristic (ROC) curve.

RESULTS

We performed 362 thoracic PS placement procedures in 39 consecutive patients. We classified 352 (97.2%), 2 (0.6%), and 8 (2.2%) screws as GR grades 0 (optimal placement), I, and II, respectively. The average instrumented PS entry point offsets on the X- and Y-axes were both 0.8 mm, and the average differences in trajectory between the planned and the actual screw placements on the oblique sagittal and oblique transverse planes were 2.0° and 2.4°, respectively. The learning process was ongoing until the first 12 PSs were placed.

CONCLUSIONS

The accuracy of PS placement using patient-specific 3D templates in our case series exceeds the accuracies of established thoracic PS placement techniques.

3D printing in spine care: A review of current applications

3D printing (3DP) has been brought to medical use since the early part of this century- but it has been widely researched on and publicized only in the last few years. Amongst patients with spinal disorders, 3DP has been utilized in various facets of patient care. These include pre-operative aspects - such as patient education, resident training, pre-operative planning and simulations, intra-operative assistance in the form of customized jigs for pedicle screw insertion, patient specific interbody cages and vertebral body substitutes in complex malignancies and spinal infections. It has also been utilized in deformity surgeries and has opened new avenues in minimally invasive spine care. Guidelines have now been drafted by various organizations including the FDA with a prime focus on quality control measures applicable to this new technology. There has been a recent surge in publications supporting the use of 3DP in spinal disorders, reporting an improvement in various aspects of patient care. As the technology spreads out its wings further, more innovations and applications are expected to unfold in the coming years. Considering the rapid advances that 3DP has made, having a basic understanding of this technology is imperative for all spine surgeons. Despite promising preliminary results, there still exist a few pitfalls of the technology which have hindered the universal application of 3DP. Most importantly, there is a dearth of data related to long term outcomes supporting its clinical use. The prohibitive cost of 3D models, the specialized manpower it necessitates and the need for specific instrumentation are major deterrents to widespread use of this technology, particularly in small-scale healthcare setups. With further advancements in technology, the goal must be to make it more accurate and affordable to hospitals and patients so that the benefits of the technology can reach a wider patient population.

Evolution of evidence in spinal surgery – past, present and future Scientometric analysis of randomized controlled trials in spinal surgery

BACKGROUND

Spine surgery is evolving and in the due course of its evolution, it is useful to have a comprehensive summary of the process to have a greater understanding to refine our future directives. With the multiple domains of research in the spine, it has become difficult for a surgeon to find the potential hotspots in research or identify the emerging research frontiers.

AIM

To analyze RCTs (1990–2019) for potential research domains along with their research networks and identify the hot topics for future research.

METHODS

A comprehensive and systematic analysis of all the RCTs published on spinal surgery from 1990 to 2019 retrieved from the Web of Science Core Collection database. Scientometric and visual analysis of their characteristics, cooperation networks, keywords, and citations were made using CiteSpace software. Journal and article impact index were retrieved from Reference Citation Analysis (RCA) Database.

RESULTS

A total of 696 RCTs were published on spinal surgery from 1990 to 2019; of which, the United States (n = 263) and China (n = 71) made a significant contribution. Thomas Jefferson University (n = 16) was the leading contributor to RCTs on spinal surgery. Weinstein JN was the most cited author in the field followed by Deyo RA. Spine (n = 559) remained the top-cited journal for RCTs on spinal surgery. On literature co-citation analysis, spinal stenosis, anterior cervical discectomy and fusion, degenerative disc disease, and minimally invasive decompression were identified as the hotspots and potential research frontiers.

CONCLUSION

The identified hotspots that extending the frontiers in the management of degenerative disorders of the spine through further research holds the potential for advancement in spinal care.

Feasibility Analysis of 3D Printing-Assisted Pedicle Screw Correction Surgery for Degenerative Scoliosis

Objective. To explore the feasibility of 3D printing-assisted pedicle screw correction surgery for degenerative scoliosis. Methods. From January 1, 2015 to January 31, 2020, patients with degenerative scoliosis who received corrective surgery in our hospital were retrospectively analyzed. Patients were grouped based on the fixation methods. Patients in the control group received traditional pedicle screw internal fixation, while those in the study group received 3D printing-assisted pedicle screw fixation. The therapeutic effects were compared. Results. There were 78 cases in the control group and 82 cases in the study group. There were no significant differences in scoliotic Cobb’s angle, pelvic incidence-lumbar lordosis (PI-LL), VAS score, JOA score, social function, physical function, role function, or cognitive function between the study group and the control group before the surgery, but there were differences in the above parameters between the two groups after surgery. The incidence of postoperative complications in the study group was also significantly lower in the study group. Conclusion. 3D printing-assisted pedicle screw correction surgery provides a strong 3D correction force with reliable effect and fewer complications, and is a good treatment choice for degenerative scoliosis.

Three-dimensional printing versus freehand surgical techniques in the surgical management of adolescent idiopathic spinal deformity

Background

Three-dimensional (3D) printed guides are finding increasing applications in the field of orthopaedic surgery and more recently spine surgery. This retrospective cohort study compares benefits and costs of 3D printed guides in surgical treatment of adolescent idiopathic scoliosis (AIS) compared to freehand techniques.

Methods

Intraoperative screw placement was conducted either with 3D printed guides (3D cohort) or traditional freehand technique (freehand cohort) for AIS patients undergoing spinal fusion at a single institution. Patient and perioperative data include: screw placement time, length of surgery, blood loss, hospital stay, spinal curvature correction, total implant costs and training level of surgical assist. Multivariate analysis assessed for confounding and effect modification. P-values <0.05 were considered significant.

Results

There were 29 patients included in analyses, 18 in the 3D and 11 in the freehand (FH) cohort, for a total of 263 3D and 307 freehand screws. Between cohorts, there were no significant differences in patient age (P=0.93), gender (P=0.15), height (P=0.18) or weight (P=0.40). The 3D cohort (mean $26,215, SD =$6,374) had significantly higher implant costs than FH (mean $18,660, SD =$5,587, P=0.003) with significantly reduced intraoperative blood loss (mean 559 mL, SD =273 FH; vs. mean 357 mL, SD =123 3D; P=0.01). On multivariate analysis, surgical residents had significantly faster screw placement times when using 3D guides (P<0.001) than when placing screws freehand. There were no significant differences between cohorts in length of postoperative hospitalization, spinal levels fused, or coronal or sagittal curve correction.

Conclusions

At significant cost, 3D printed guides reduce intraoperative blood loss compared to freehand pedicle screw placement and reduce screw placement time for surgical residents.

3D printed templates improve the accuracy and safety of pedicle screw placement in the treatment of pediatric congenital scoliosis

Background

Three-dimensional (3-D) printed guidance templates are being increasingly used in spine surgery. The purpose of this study was to determine if 3D printed navigation templates can improve the accuracy of pedicle screw placement and decrease the complication rate compared to freehand screw placement in the treatment of children with congenital scoliosis.

Methods

The records of pediatric patients with congenital scoliosis treated at our hospital from January 2017 to January 2019 were retrospectively reviewed. Patients were divided into those where a 3D printed guidance templated was used and those in which the freehand method was used for pedicle screw placement. The accuracy rate of pedicle screw placement, surgical outcomes, and complications were compared between groups.

Results

A total of 67 children with congenital scoliosis were included (43 males and 24 females; mean age of 4.13 ± 2.66 years; range, 2–15 years). There were 34 children in the template-assisted group and 33 in the freehand group. The excellent accuracy rate of pedicle screw placement was significantly higher in the template-assisted group (96.10% vs. 88.64%, P = 0.007). The main Cobb angle and kyphosis angle were similar between the 2 groups preoperatively and postoperatively (all, P > 0.05), and in both groups both angles were significantly decreased after surgery as compared to the preoperative values (all, P < 0.001). The degree of change of the Cobb angle of the main curve and kyphosis angle were not significantly different between the 2 groups. There were no postoperative complications in the template group and 4 in the freehand group (0% vs. 12.12%; P = 0.009). All 4 patients with complications required revision surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04892-4.

Complicated Postoperative Flat Back Deformity Correction With the Aid of Virtual and 3D Printed Anatomical Models: Case Report

Introduction: The number of patients with iatrogenic spinal deformities is increasing due to the increase in instrumented spinal surgeries globally. Correcting a deformity could be challenging due to the complex anatomical and geometrical irregularities caused by previous surgeries and spine degeneration. Virtual and 3D printed models have the potential to illuminate the unique and complex anatomical-geometrical problems found in these patients.

Case Presentation: We present a case report with 6-months follow-up (FU) of a 71 year old female patient with severe sagittal and coronal malalignment due to repetitive discectomy, decompression, laminectomy, and stabilization surgeries over the last 39 years. The patient suffered from severe low back pain (VAS = 9, ODI = 80). Deformity correction by performing asymmetric 3-column pedicle subtraction osteotomy (PSO) and stabilization were decided as the required surgical treatment. To better understand the complex anatomical condition, a patient-specific virtual geometry was defined by segmentation based on the preoperative CT. The geometrical accuracy was tested using the Dice Similarity Index (DSI). A complex 3D virtual plan was created for the surgery from the segmented geometry in addition to a 3D printed model.

Discussion: The segmentation process provided a highly accurate geometry (L1 to S2) with a DSI value of 0.92. The virtual model was shared in the internal clinical database in 3DPDF format. The printed physical model was used in the preoperative planning phase, patient education/communication and during the surgery. The surgery was performed successfully, and no complications were registered. The measured change in the sagittal vertical axis was 7 cm, in the coronal plane the distance between the C7 plumb line and the central sacral vertical line was reduced by 4 cm. A 30° correction was achieved for the lumbar lordosis due to the PSO at the L4 vertebra. The patient ODI was reduced to 20 points at the 6-months FU.

Conclusions: The printed physical model was considered advantageous by the surgical team in the pre-surgical phase and during the surgery as well. The model was able to simplify the geometrical problems and potentially improve the outcome of the surgery by preventing complications and reducing surgical time.