Ten techniques for improving navigated spinal surgery

Spine Surgery with Electronic Conductivity Device: A Prospectively Multicenter Randomized Clinical Trial and Literature Review

OBJECTIVE

Improving accuracy and safety of pedicle screw placement is of great clinical importance. Electronic conductivity device (ECD) can be a promising technique with features of affordability, portability, and real-time detection capabilities. This study aimed to validate the safety and effectiveness of a modified ECD.

METHODS

The ECD underwent a modification where six lamps of various colors, and it was utilized in a prospectively multicenter randomized controlled clinical trial involving 96 patients across three hospitals from June 2018 to December 2018. The trial incorporated a self-control randomization with an equal distribution of left or right side of vertebral pedicle among two groups: the free-hand group and the ECD group. A total of 496 pedicle screws were inserted, with 248 inserted in each group. The primary outcomes focused on the accuracy of pedicle screw placement and the frequency of intraoperative X-rays. Meanwhile, the secondary indicator measured the time required for pedicle screw placement. Results were presented as means ± SD. Paired samples t-test and χ2 -test were used for comparison. Furthermore, an updated review was conducted, which included studies published from 2006 onwards.

RESULTS

Baseline patient characteristics were recorded. The primary accuracy outcome revealed a 96.77% accuracy rate in the ECD group, compared to a 95.16% accuracy rate in the free-hand group, with no significant differences noted. In contrast, ECD demonstrated a significant reduction in radiation exposure frequency when compared to the free-hand group (1.11 ± 0.32 vs. 1.30 ± 0.53; p < 0.001), resulting in a 14.6% reduction. Moreover, ECD displayed a decrease of 30.38% in insertion time (70.88 ± 30.51 vs. 101.82 ± 54.00 s; p < 0.001). According to the results of the 21 studies, ECD has been utilized in various areas of the spine such as the atlas, thoracic and lumbar spine, as well as sacral 2-alar-iliac. The accuracy of ECD ranged from 85% to 100%.

CONCLUSION

The prospectively randomized trial and the review indicate that the use of ECD presents a secure and precise approach to the placement of pedicle screws, with the added benefit of reducing both procedure time and radiation exposure.

Impact of Navigation on 30-Day Outcomes for Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective database study.

OBJECTIVE

Navigation has been increasingly used to treat degenerative disease, with positive radiographic and clinical outcomes and fewer adverse events and reoperations, despite increased operative time. However, short-term analysis on treating adult spinal deformity (ASD) surgery with navigation is limited, particularly using large nationally represented cohorts. This is the first large-scale database study to compare 30-day readmission, reoperation, morbidity, and value-per-operative time for navigated and conventional ASD surgery.

METHODS

Adults were identified in the National Surgical Quality Improvement Program (NSQIP) database. Multivariate regression was used to compare outcomes between navigated and conventional surgery and to control for predictors and baseline differences.

RESULTS

3190 ASD patients were included. Navigated and conventional patients were similar. Navigated cases had greater operative time (405 vs 320 min) and mean RVUs per case (81.3 vs 69.7), and had more supplementary pelvic fixations (26.1 vs 13.4%) and osteotomies (50.3 vs 27.7%) (P <.001).In univariate analysis, navigation had greater reoperation (9.9 vs 5.2%, P = .011), morbidity (57.8 vs 46.8%, P = .007), and transfusion (52.2 vs 41.8%, P = .010) rates. Readmission was similar (11.9 vs 8.4%). In multivariate analysis, navigation predicted reoperation (OR = 1.792, P = .048), but no longer predicted morbidity or transfusion. Most reoperations were infectious and hardware-related.

CONCLUSIONS

Despite controlling for patient-related and procedural factors, navigation independently predicted a 79% increased odds of reoperation but did not predict morbidity or transfusion. Readmission was similar between groups. This is explained, in part, by greater operative time and transfusion, which are risk factors for infection. Reoperation most frequently occurred for wound- and hardware-related reasons, suggesting navigation carries an increased risk of infectious-related events beyond increased operative time.

Advances in robotics and pediatric spine surgery

PURPOSE OF REVIEW

Robotic-assisted surgical navigation for placement of pedicle screws is one of the most recent technological advancements in spine surgery. Excellent accuracy and reliability results have been documented in the adult population, but adoption of robotic surgical navigation is uncommon in pediatric spinal deformity surgery. Pediatric spinal anatomy and the specific pediatric pathologies present unique challenges to adoption of robotic assisted spinal deformity workflows. The purpose of this article is to review the safety, accuracy and learning curve data for pediatric robotic-assisted surgical navigation as well as to identify "best use" cases and technical tips.

RECENT FINDINGS

Robotic navigation has been demonstrated as a safe, accurate and reliable method to place pedicle screws in pediatric patients with a moderate learning curve. There are no prospective studies comparing robotically assisted pedicle screw placement with other techniques for screw placement, however several recent studies in the pediatric literature have demonstrated high accuracy and safety as well as high reliability. In addition to placement of pediatric pedicle screws in the thoracic and lumbar spine, successful and safe placement of screws in the pelvis and sacrum have also been reported with reported advantages over other techniques in the setting of high-grade spondylolisthesis as well as pelvic fixation utilizing S2-alar iliac (S2AI) screws.

SUMMARY

Early studies have demonstrated that robotically assisted surgical navigation for pedicle screws and pelvic fixation for S2AI screws is safe, accurate, and reliable in the pediatric population with a moderate learning curve.

3D Visualisation of the Spine

The 3D visualisation of the spine is thought of from multiple viewpoints. Firstly, radiological imaging is considered, with plain radiography, CT and MRI imaging discussed in detail with relevant applications to spinal surgery.3D printing can be used in spinal surgery with multiple applications including education, pre-operative planning for complex cases and making patient-specific guides and implants. The rapidly growing field of intraoperative navigation and robotics have been discussed, in addition to their benefits and limitations within spinal surgery, as well as some technical tips.An understanding of relevant anatomy and biomechanics is necessary for any surgeon, and so this chapter describes the key concepts to be familiar with, particularly the spinal motion segment and the different methods for classifying spinal injuries and how that relates to stability. The concepts discussed have been brought together by applying this knowledge to some interesting clinical cases. They highlight the importance of 3D visualisation of the spine, which must be considered throughout the decision-making process when managing patients. Spinal surgeons use multiple imaging modalities, knowledge of anatomy and biomechanics, as well as considering the need for navigation in more complex cases, all on a daily basis. With the advancement of technology available for 3D visualisation of the spine, we will be able to improve patient outcomes even further in the future.

Sacroiliac joint fusion navigation: how accurate is pin placement?

OBJECTIVE

Sacroiliac joint (SIJ) fusion utilizing intraoperative navigation requires a standard reference frame, which is often placed using a percutaneous pin. Proper placement ensures the correct positioning of SIJ fusion implants. There is currently no grading scheme for evaluation of pin placement into the pelvis. The purpose of this study was to evaluate the occurrence of ideal percutaneous pin placement into the posterior ilium during navigated SIJ fusion.

METHODS

After IRB approval was obtained, electronic medical records and intraoperative computed tomography images of patients who underwent navigated SIJ fusion by the senior author between October 2013 and January 2020 were reviewed. A pin placement grading scheme and the definition of "ideal" placement were developed by the authors and deemed acceptable by fellow attending surgeons. Six attending surgeons completed two rounds of pin placement grading, and statistical analysis was conducted.

RESULTS

Of 90 eligible patients, 73.3% had ideal pin placement, 17.8% medial/lateral breach, and 8.9% complete miss. Male patients were 3.7 times more likely to have ideal placement than females (p < 0.05). There was no relationship between BMI, SIJ fusion laterality, or pin placement laterality and ideal placement. Interobserver reliability was 0.72 and 0.70 in the first and second rounds, respectively, and defined as "substantial agreement." Intraobserver reliability ranged from 0.74 (substantial agreement) to 0.92 (almost perfect agreement).

CONCLUSIONS

Nonideal pin placement occurred in 26.7% of cases, but a true "miss" into the sacrum was rare. Ideal pin placement was more likely in males and was not associated with BMI, SIJ fusion laterality, or pin placement laterality. The grading scheme developed has high intraobserver and interobserver reliability, indicating that it is reproducible and can be used for future studies. When placing percutaneous pins, surgeons must be aware of factors that can decrease placement accuracy, regardless of location.

Assessing the influence of modifiable patient-related factors on complication rates after adult spinal deformity surgery

Aims

Postoperative complication rates remain relatively high after adult spinal deformity (ASD) surgery. The extent to which modifiable patient-related factors influence complication rates in patients with ASD has not been effectively evaluated. The aim of this retrospective cohort study was to evaluate the association between modifiable patient-related factors and complications after corrective surgery for ASD.

Methods

ASD patients with two-year data were included. Complications were categorized as follows: any complication, major, medical, surgical, major mechanical, major radiological, and reoperation. Modifiable risk factors included smoking, obesity, osteoporosis, alcohol use, depression, psychiatric diagnosis, and hypertension. Patients were stratified by the degree of baseline deformity (low degree of deformity (LowDef)/high degree of deformity (HighDef): below or above 20°) and age (Older/Younger: above or below 65 years). Complication rates were compared for modifiable risk factors in each age/deformity group, using multivariable logistic regression analysis to adjust for confounders.

Results

A total of 480 ASD patients met the inclusion criteria. By two years, complication rates were 72% ≥ one complication, 28% major, 21% medical, 27% surgical, 11% major radiological, 8% major mechanical, and 22% required reoperation. Younger LowDef patients with osteoporosis were more likely to suffer either a major mechanical (odds ratio (OR) 5.9 (95% confidence interval (CI) 1.1 to 36.9); p = 0.048) or radiological complication (OR 7.0 (95% CI 1.9 to 25.9); p = 0.003). Younger HighDef patients were much more likely to develop complications if obese, especially major mechanical complications (OR 2.8 (95% CI 1.1 to 8.6); p = 0.044). Older HighDef patients developed more complications when diagnosed with depression, including major radiological complications (OR 3.5 (95% CI 1.1 to 10.6); p = 0.033). Overall, a diagnosis of depression proved to be a risk factor for the development of major radiological complications (OR 2.4 (95% CI 1.3 to 4.5); p = 0.005).

Conclusion

Certain modifiable patient-related factors, especially osteoporosis, obesity, and mental health status, are associated with an increased risk of complications after surgery for spinal deformity. Surgeons should look for these conditions when assessing a patient for surgery, and optimize them to the fullest extent possible before proceeding to surgical correction so as to minimize the prospect of postoperative morbidity. Cite this article: Bone Joint J 2022;104-B(11):1249–1255.

Safety and risk factors of TINAVI robot-assisted percutaneous pedicle screw placement in spinal surgery

Objective

To determine the rates and risk factors of pedicle screw placement accuracy and the proximal facet joint violation (FJV) using TINAVI robot-assisted technique.

Methods

Patients with thoracolumbar fractures or degenerative diseases were retrospectively recruited from June 2018 and June 2020. The pedicle penetration and proximal FJV were compared in different instrumental levels to identify the safe and risk segments during insertion. Moreover, the factors were also assessed using univariate and multivariate analyses.

Results

A total of 72 patients with 332 pedicle screws were included in the current study. The optimal and clinically acceptable screw positions were 85.8% and 93.4%. Of the 332 screws concerning the intra-pedicular accuracy, 285 screws (85.8%) were evaluated as Grade A according to the Gertzbein and Robbins scale, with the remaining 25 (7.6%), 10 (3.0%), 6 (1.8%), and 6 screws (1.8%) as Grades B, C, D, and E. Moreover, in terms of the proximal FJV, 255 screws (76.8%) screws were assessed as Grade 0 according to the Babu scale, with the remaining 34 (10.3%), 22 (6.6%), and 21 screws (6.3%) as Grades 1, 2, and 3. Furthermore, the univariate analysis showed significantly higher rate of penetration for patients with age < 61 years old, sex of female, thoracolumbar insertion, shorter distance from skin to insertion point, and smaller facet angle. Meanwhile, the patients with the sex of female, BMI < 25.9, grade I spondylolisthesis, lumbosacral insertion, longer distance from skin to insertion point, and larger facet angle had a significantly higher rate of proximal FJV. The outcomes of multivariate analyses showed that sex of male (adjusted OR 0.320, 95% CI 0.140–0.732; p = 0.007), facet angle ≥ 45° (adjusted OR 0.266, 95% CI 0.090–0.786; p = 0.017), distance from skin to insertion point ≥ 4.5 cm (adjusted OR 0.342, 95% CI 0.134–0.868; p = 0.024), and lumbosacral instrumentation (adjusted OR 0.227, 95% CI 0.091–0.566; p = 0.001) were independently associated with intra-pedicular accuracy; the L5 insertion (adjusted OR 2.020, 95% CI 1.084–3.766; p = 0.027) and facet angle ≥ 45° (adjusted OR 1.839, 95% CI 1.026–3.298; p = 0.041) were independently associated with the proximal FJV.

Conclusion

TINAVI robot-assisted technique was associated with a high rate of pedicle screw placement and a low rate of proximal FJV. This new technique showed a safe and precise performance for pedicle screw placement in spinal surgery. Facet angle ≥ 45° is independently associated with both the intra-pedicular accuracy and proximal FJV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03271-6.

Posterior Surgery in the Treatment of Craniovertebral Junction Deformity with Torticollis

OBJECTIVE

To investigate the clinical effect of posterior surgery in the treatment of craniovertebral junction (CVJ) deformities with torticollis and methods for preventing and treating complications in order to obtain a reasonable treatment strategy.

METHODS

From January 2007 to December 2017, 78 patients who suffered from CVJ deformities with torticollis treated by posterior surgery were analyzed. The surgical techniques were all posterior correction and fusion to restore the anatomical alignment of the craniovertebral junction. The visual analog score (VAS) and Short Form-36 (SF-36) health survey questionnaire were utilized to evaluate preoperative and postoperative neck pain, and changes in the torticollis angle and atlas-dens interval (ADI) were evaluated through anteroposterior X-ray and computed tomography. Intra- and postoperative complications were all recorded. One-way ANOVA, LSD-t test, and χ² test were performed to evaluate the difference between the preoperative and postoperative data.

RESULTS

The mean follow-up time was 37.4 ± 15.7 months, the average operation time was 115.6 ± 12.8 min, and the average blood loss was 170.8 ± 26.3 mL. According to the deformity site, the range of posterior correction and fusion was as follows: 38 cases of C₁ -C₂ , 33 cases of C₀ -C₂ , and seven cases of C₀ -C₃ . The preoperative SF-36, VAS, torticollis angle, and ADI were 42.6 ± 8.8, 4.8 ± 1.1, 37.2 ± 11.2°, and 4.9 ± 2.3 mm, respectively. The difference was significant at 3 months post operation (p < 0.05), and there was no significant difference at the final follow-up compared with 3 months post operation (p > 0.05).

CONCLUSION

It can objectively achieve favorable correction and satisfactory clinical effects under posterior correction and fixation for CVJ deformities with torticollis. Intra- and postoperative complications can be settled by proper management.

Intraoperative 3D Imaging Reduces Pedicle Screw Related Complications and Reoperations in Adolescents Undergoing Posterior Spinal Fusion for Idiopathic Scoliosis: A Retrospective Study

Widely used surgical treatment for adolescent idiopathic scoliosis (AIS) is posterior spinal fusion using pedicle screw instrumentation (PSI). Two-dimensional (2D) or three-dimensional (3D) navigation is used to track the screw positioning during surgery. In this study, we evaluated the screw misplacement, complications, and need for reoperations of intraoperative 3D as compared to 2D imaging in AIS patients. There were 198 adolescents, of which 101 (51%) were evaluated with 2D imaging and 97 (49%) with 3D imaging. Outcome parameters included radiographic correction, health-related quality of life (HRQOL), complications, and reoperations. The mean age was 15.5 (SD 2.1) years at the time of the surgery. Forty-four (45%) patients in the 3D group and 13 (13%) patients in the 2D group had at least one pedicle screw repositioned in the index operation (p < 0.001). Six (6%) patients in the 2D group, and none in the 3D group had a neurological complication (p = 0.015). Five (5%) patients in the 2D group and none in the 3D group required reoperation (p = 0.009). There were no significant differences in HRQOL score at two-year follow-up between the groups. In conclusion, intraoperative 3D imaging reduced pedicle screw-related complications and reoperations in AIS patients undergoing PSI as compared with 2D imaging.

Radiation exposure during the treatment of spinal deformities

AIMS

To benchmark the radiation dose to patients during the course of treatment for a spinal deformity.

METHODS

Our radiation dose database identified 25,745 exposures of 6,017 children (under 18 years of age) and adults treated for a spinal deformity between 1 January 2008 and 31 December 2016. Patients were divided into surgical (974 patients) and non-surgical (5,043 patients) cohorts. We documented the number and doses of ionizing radiation imaging events (radiographs, CT scans, or intraoperative fluoroscopy) for each patient. All the doses for plain radiographs, CT scans, and intraoperative fluoroscopy were combined into a single effective dose by a medical physicist (milliSivert (mSv)).

RESULTS

There were more ionizing radiation-based imaging events and higher radiation dose exposures in the surgical group than in the non-surgical group (p < 0.001). The difference in effective dose for children between the surgical and non-surgical groups was statistically significant, the surgical group being significantly higher (p < 0.001). This led to a higher estimated risk of cancer induction for the surgical group (1:222 surgical vs 1:1,418 non-surgical). However, the dose difference for adults was not statistically different between the surgical and non-surgical groups. In all cases the effective dose received by all cohorts was significantly higher than that from exposure to natural background radiation.

CONCLUSION

The treatment of spinal deformity is radiation-heavy. The dose exposure is several times higher when surgical treatment is undertaken. Clinicians should be aware of this and review their practices in order to reduce the radiation dose where possible. Cite this article: Bone Joint J 2021;103-B(4):1-7.

Accuracy of Pedicle Screw Placement and Four Other Clinical Outcomes of Robotic Guidance Technique versus Computer-Assisted Navigation in Thoracolumbar Surgery: A Meta-Analysis

BACKGROUND

Robotic guidance (RG) pedicle screw placement has been increasingly used to improve the rate of insertion accuracy. However, the superiority of the RG technique over computer-assisted navigation (CAN) remains debatable.

OBJECTIVE

To determine whether the Mazor RG technique is superior to CAN in terms of the rate of insertion accuracy and 4 other clinical indices, namely, intraoperative time, blood loss, complications and revision surgery caused by malposition.

METHODS

A search of PubMed, Embase, Cochrane, Web of Science, CNKI, and WanFang was conducted. We mainly aimed to evaluate the accuracy of pedicle screw placement between the Mazor RG and CAN techniques. The secondary objectives were intraoperative time, blood loss, complications, and revision surgery caused by malposition. The meta-analysis was conducted using the RevMan 5.3 and Stata 15.1 software.

RESULTS

A randomized controlled trial and 5 comparative cohort studies consisting of 529 patients and 4081 pedicle screws were included in this meta-analysis. The RG technique has a significantly higher accuracy than CAN in terms of optimal (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.85-2.76; P < 0.01) and clinically acceptable (OR, 1.69; 95% CI, 1.22-2.34; P = 0.002) pedicle screw insertions. Furthermore, the RG technique showed significantly less blood loss (mean difference, -42.49; 95% CI, -78.38 to -6.61; P = 0.02) than did the CAN technique but has equivalent intraoperative time (mean difference, 0.75; 95% CI, -5.89 to 7.40; P = 0.82), complications (OR, 0.65; 95% CI, 0.32-1.33, P = 0.24), and revision surgery caused by malposition (OR, 0.46; 95% CI, 0.15-1.43, P = 0.18).

CONCLUSIONS

The Mazor RG technique is superior to CAN concerning the accuracy of pedicle screw placement. Thus, the Mazor RG technique is accurate and safe in clinical application.