Effect of guided implant placement learning experiences on freehand skills: A pilot study

OBJECTIVES

Guided implant systems can be used as a training approach for placing implants. This in vitro prospective randomized pilot study evaluated the learning progression and skill development in freehand placement of two implants supporting a three-unit fixed prosthesis on a simulation model among novice operators.

MATERIAL AND METHODS

Four senior dental students with no prior implant placement experience participated in the study. As a baseline, each student placed two mandibular and two maxillary implants by freehand technique on a simulation model. Sixteen consecutive guided placements using a static guide, dynamic navigation, and template-based guide followed totaling 32 guided implant placements into maxillary and mandibular models. Freehand implant placements before and after the various guided navigation attempts were compared to assess their impact on freehand skill. Metrics compared included surgical time, horizontal, vertical, and angulation discrepancies between the planned and placed implant positions measured on superimposed CBCT scans and analyzed with repeated measures regression with Tukey's adjusted pairwise comparisons (α = .05).

RESULTS

Before training with guided techniques, the average baseline freehand implant placement took 10.2 min and decreased to 8.2 after training but this difference was not statistically significant (p = .1670) There was marginal evidence of a significant difference in the 3D apex deviation with an average improvement of 0.89 mm (95% CI: -0.38, 2.16, p = .1120); and marginal evidence of a significant improvement in the overall angle with an average improvement of 3.74° (95% CI: -1.00, 8.48, p = .0869) between baseline and final freehand placement attempts.

CONCLUSIONS

Within the limitations of this pilot study, guided implant placement experiences did not significantly benefit or hinder freehand placement skills. Dental students should be exposed to various placement techniques to prepare them for clinical practice and allow them to make informed decisions on the best technique based on their skills and a given clinical scenario.

Comparing the accuracies of freehand, static computer-assisted and robot-assisted dental implant placements: an in vitro study

OBJECTIVE

To compare the accuracies among three oral implant surgical techniques: freehand (FH), static computer-assisted implant surgery (sCAIS), and robotic computer-assisted implant surgery (rCAIS).

METHODS

The polyurethane and bovine femur implant models were fabricated, and 126 and 96 implant sites were designed on them. The implant sites were divided into three groups: FH, sCAIS, and rCAIS, according to the implantation method. The deviation between the actual implant position and the planned position was analyzed and compared by cone beam computed tomography.

RESULTS

In the polyurethane model test, the entry deviation, entry-level deviation, apical deviation, apical level deviation, and angle deviation in sCAIS and rCAIS groups were significantly reduced compared with those in the FH group (P<0.05). No significant differences were observed in all kinds of deviations between the sCAIS and rCAIS groups (P>0.05). In the bovine femur model test, the entry deviation, entry-level deviation, apical deviation, apical level deviation, and angle deviation in both sCAIS and rCAIS groups were significantly reduced compared with those in the FH group (P<0.05). No significant differences were observed in all kinds of deviations between the sCAIS and rCAIS groups (P>0.05).

CONCLUSION

This in vitro study shows that the rCAIS technique is superior to the freehand, but has the same accuracy as the sCAIS.

Influence of different education approaches on the implantation performance of dental practitioners in aesthetic zone

PURPOSE

To investigate the influence of different education approaches on the implantation performance (operation time, three-dimensional deviation) of inexperienced operators.

METHODS

Eighteen students who met the inclusion criteria were randomly assigned to traditional training group or digital training group. After training, the average operation time and implant deviation (platform deviation, apex deviation, and angle deviation) of the two groups were calculated by Student's t-test. A self-developed questionnaire was used to evaluate the students' grasp of clinical knowledge and skill.

RESULT

Compared with the traditional training group, the duration of implant installation and temporary prosthesis placement of the digital training group decreased significantly (p < 0.05). The implant deviation of the digital training group was lower than that of the traditional training group. The apex deviation (p = 0.015) and angle deviation (p = 0.015) significantly improved with digital training, but differences in platform deviation (p = 0.065) were not statistically significant. The questionnaire survey showed that the overall perception of the inexperienced operators in the digital training group was better than that in the traditional training group.

CONCLUSION

In the hands of inexperienced operators, digital training reduced the operation time and improved the implant accuracy in comparison with traditional training.

Freehand S2-Alar-Iliac Screw Placement Technique in Lumbosacral Spinal Tumors: A Preliminary Study

OBJECTIVE

S2-alar-iliac (S2AI) screw technique is widely used in spinal surgery, but it is rarely seen in the field of spinal tumors. The aim of the study is to report the preliminary outcomes of the freehand S2AI screw fixation after lumbosaral tumor resection.

METHODS

The records of patients with lumbosacral tumor who underwent S2AI screw fixation between November 2016 to November 2020 at our center were reviewed retrospectively. Outcome measures included operative time, blood loss, complications, accuracy of screws, screw breach, and overall survival. Mean ± standard deviation or range was used to present continuous variables. Kaplan-Meier curve was used to present postoperative survival.

RESULTS

A total of 23 patients were identified in this study, including 12 males and 11 females, with an average age of 47.3 ± 14.5 (range,15-73). The mean operation time was 224.6 ± 54.1 (range, 155-370 min). The average estimated blood loss was 1560.9 ± 887.0 (600-4000 ml). A total of 46 S2AI screws were implanted by freehand technique. CT scans showed three (6.5%) screws had penetrated the iliac cortex, indicating 93.5% implantation accuracy rate. No complications of iatrogenic neurovascular or visceral structure were observed. The average follow-up time was 31.6 ± 15.3 months (range, 13-60 months). Two patients' postoperative plain radiography showed lucent zone around the screw. One patient underwent reoperation for wound delayed infection. At the latest follow-up, eight patients had tumor-free survival, 11 had survival with tumor, and four died of disease.

CONCLUSION

The freehand S2AI screw technique is reproducible, safe, and reliable in the management of lumbosacral spinal tumors.

Robotic laser position versus freehand in CT-guided percutaneous microwave ablation for single hepatocellular carcinoma (diameter < 3 cm): a preliminary study

PURPOSE

To compare the accuracy and safety of robotic laser position (RLP) versus freehand for antenna CT-guided microwave ablation (MWA) of single hepatocellular carcinoma (HCC) (diameter < 3 cm).

MATERIALS AND METHODS

This retrospective study was conducted between May 2020 and June 2021. A total of 40 patients with early HCC who underwent CT-guided MWA were divided into two groups: a freehand group (n = 20) and a RLP group (n = 20). Based on in-plane and out-of-plane data, the actual puncture point error (APPE), number of repositioning procedures, and operative duration were compared using the Mann-Whitney U test. Ablation-related complications were compared using the Chi-squared test.

RESULTS

The mean diameter of HCC patients who received MWA was 2.4 ± 0.5 cm. For in-plane APPE, APPE was comparable between the two groups (p = 0.299). However, for the out-of-plane position, the APPE in the freehand group was higher than that in the RLP group (p = 0.027). The number of repositioning procedures was 0 (range, 0-0) for RLP-guided procedures and 3 (range, 2-5) for freehand procedures, showing a statistically significant difference between the two groups (p < 0.001). The mean operative duration for freehand procedures was 39 min, compared with 26 min for RLP-guided procedures, showing a significant difference (p = 0.013). No deaths or major complications were directly related to MWA. Minor complications in the freehand group were comparable with those in the RLP group (p = 0.313).

CONCLUSION

RLP guidance significantly reduces the number of antenna repositioning procedures in MWA and improves puncture accuracy for target HCC out-of-plane. In addition, the operative duration of robotic guidance was shorter than that of freehand guidance.

Freehand Transperineal Prostate Biopsy with Three-Dimensional Ultrasound Organ-Based Tracking

Transperineal prostate biopsy carries a significantly lower risk of infectious complications compared with the transrectal approach. We provide a step-by-step description of our current procedural technique for performing transperineal prostate biopsy under local anesthesia. A key component of our technique is the use of a disposable, probe-mounted needle guide that minimizes the number punctures to the perineal skin and allows for continuous needle visualization throughout the procedure. We have paired this device with a novel fusion biopsy platform that utilizes three-dimensional transrectal ultrasound to enable targeting of suspicious lesions found prebiopsy MRI as well as allows for mapping of biopsy core locations for postprocedure review and use at the time of subsequent prostate biopsy or ablation procedures.

The effect of augmented reality on the accuracy and learning curve of external ventricular drain placement

OBJECTIVE

The traditional freehand technique for external ventricular drain (EVD) placement is most frequently used, but remains the primary risk factor for inaccurate drain placement. As this procedure could benefit from image guidance, the authors set forth to demonstrate the impact of augmented-reality (AR) assistance on the accuracy and learning curve of EVD placement compared with the freehand technique.

METHODS

Sixteen medical students performed a total of 128 EVD placements on a custom-made phantom head, both before and after receiving a standardized training session. They were guided by either the freehand technique or by AR, which provided an anatomical overlay and tailored guidance for EVD placement through inside-out infrared tracking. The outcome was quantified by the metric accuracy of EVD placement as well as by its clinical quality.

RESULTS

The mean target error was significantly impacted by either AR (p = 0.003) or training (p = 0.02) in a direct comparison with the untrained freehand performance. Both untrained (11.9 ± 4.5 mm) and trained (12.2 ± 4.7 mm) AR performances were significantly better than the untrained freehand performance (19.9 ± 4.2 mm), which improved after training (13.5 ± 4.7 mm). The quality of EVD placement as assessed by the modified Kakarla scale (mKS) was significantly impacted by AR guidance (p = 0.005) but not by training (p = 0.07). Both untrained and trained AR performances (59.4% mKS grade 1 for both) were significantly better than the untrained freehand performance (25.0% mKS grade 1). Spatial aptitude testing revealed a correlation between perceptual ability and untrained AR-guided performance (r = 0.63).

CONCLUSIONS

Compared with the freehand technique, AR guidance for EVD placement yielded a higher outcome accuracy and quality for procedure novices. With AR, untrained individuals performed as well as trained individuals, which indicates that AR guidance not only improved performance but also positively impacted the learning curve. Future efforts will focus on the translation and evaluation of AR for EVD placement in the clinical setting.

Robot-assisted vs freehand cannulated screw placement in femoral neck fractures surgery: A systematic review and meta-analysis

BACKGROUND

Several studies have reported that medical robot-assisted method (RA) might be superior to conventional freehand method (FH) in orthopedic surgery. Yet the results are still controversial, especially in terms of femoral neck fractures surgery. Here, 2 methods were assessed based on current evidence.

METHODS

Electronic databases including Cochrane Library, PubMed, Web of Science. and EMBASE were selected to retrieved to identify eligible studies between freehand and RAs in femoral neck fractures, with 2 reviewers independently reviewing included studies as well as collecting data.

RESULTS

A total of 5 studies with 331 patients were included. Results indicated that 2 surgical methods were equivalent in terms of surgical duration, Harris score, fracture healing time, fracture healing proportion and complications, while RA showed clinical benefits in radiation exposure, intraoperative bleeding, total drilling times, and screw parallelism.

CONCLUSIONS

Current literature revealed significantly difference between 2 techniques and suggested that RA might be beneficial for patients than freehand method.

Factors Influencing the Accuracy of Freehand Implant Placement: A Prospective Clinical Study

(1) Background: The objective of implant prosthetic restoration is to ensure the best possible rehabilitation of function and esthetics. Optimal positioning of the implant with regard to the bone availability, surrounding soft tissue, and prosthetic sustainability should be strived for during implant placement. The factors influencing freehand implant placement and the accuracy achieved with this procedure are investigated in this prospective clinical study. (2) Methods: Implants were placed in the single-tooth edentulous sites of the premolar and molar areas in 52 patients. Three-dimensional (3D)-planning was performed virtually prior to the freehand implant operation, and the desired position of the implant was provided to the surgeon. (3) Results: The deviations between the planned and the actually achieved position with freehand implant placement showed the following mean values and standard deviations: angle 8.7 ± 4.8°, 3D deviation at the implant shoulder 1.62 ± 0.87 mm, mesiodistal deviation 0.87 ± 0.75 mm, buccolingual deviation 0.70 ± 0.66 mm, and apiocoronal deviation 0.95 ± 0.61 mm. The type of jaw had a significant influence on accuracy. Major deviations were observed in the lower jaw. Furthermore, the timing of implant placement influenced the mesiodistal deviation and angular deviation; (4) Conclusions: Freehand implant placement demonstrated a higher level of deviation between the planned and actually achieved implant positions. In particular, the ranges showed a large spread. From a prosthetic point of view, there may be complications during the restoration of the prosthetic crown if the implant exit point is not optimally located or if the implants show a high angular deviation.

Accuracy and deviation analysis of robot-assisted spinal implants: A retrospective overview of 105 cases and preliminary comparison to open freehand surgery in lumbar spondylolisthesis

BACKGROUND

Whether the accuracy of robot-assisted spinal screw placement is significantly higher than that of freehand and the source of robotic deviation remain unclear.

METHODS

Clinical data of 105 patients who underwent robot-assisted spinal surgery was collected, and screw accuracy was evaluated by computed tomography according to the modified Gertzbein-Robbins classification. Patients were grouped by percutaneous and open surgery. Intergroup comparisons of clinical and screw accuracy parameters were performed. Reasons for deviation were determined. Thirty-one patients with lumbar spondylolisthesis undergoing open robot-assisted surgery and the same number of patients treated by open freehand surgery were compared for screw accuracy.

RESULTS

Screw accuracy was not significantly different between the percutaneous and open groups in both intra- and postoperative evaluations. Tool skiving was identified as the main cause of deviation. The proportion of malpositioned screws (grade B + C + D) was significantly higher in the freehand group than in the robot-assisted group. However, remarkably malpositioned (grade C + D) screws showed no significant differences between the groups. No revision surgery was necessary.

CONCLUSIONS

Robot-assisted spinal instrumentation manifests high accuracy and low incidence of nerve injury. Tool skiving is a major cause of implant deviation.

Versatile Low-Cost Volumetric 3D Ultrasound Imaging Using Gimbal-Assisted Distance Sensors and an Inertial Measurement Unit

This study aims at creating low-cost, three-dimensional (3D), freehand ultrasound image reconstructions from commercial two-dimensional (2D) probes. The low-cost system that can be attached to a commercial 2D ultrasound probe consists of commercial ultrasonic distance sensors, a gimbal, and an inertial measurement unit (IMU). To calibrate irregular movements of the probe during scanning, relative position data were collected from the ultrasonic sensors that were attached to a gimbal. The directional information was provided from the IMU. All the data and 2D ultrasound images were combined using a personal computer to reconstruct 3D ultrasound image. The relative position error of the proposed system was less than 0.5%. The overall shape of the cystic mass in the breast phantom was similar to those from 2D and sections of 3D ultrasound images. Additionally, the pressure and deformations of lesions could be obtained and compensated by contacting the probe to the surface of the soft tissue using the acquired position data. The proposed method did not require any initial marks or receivers for the reconstruction of a 3D ultrasound image using a 2D ultrasound probe. Even though our system is less than $500, a valuable volumetric ultrasound image could be provided to the users.

A Novel Intraoperative Technique to Determine Cranio-Caudal Angulation of Pedicle Screws in Thoracolumbar Spine: A Prospective Computerized Tomography-Based Analysis of 428 Screws

BACKGROUND

We report a novel technique of directing the sagittal profile of thoracic and lumbar pedicle screws using a freehand technique without the use of intraoperative monitoring.

METHODS

This is a prospective computerized tomography (CT)-based evaluation of pedicle screw insertion in the thoracic and lumbar spine of 64 patients operated upon for varied etiologies. All the patients were operated upon independently by 2 young surgeons with 1 year of spinal-fellowship experience. Intraoperatively, a right-angle retractor was positioned to determine the sagittal inclination of the pedicle screw. Postoperatively, sagittal CT scans were analyzed for the sagittal profile of the screw. The vertebral bodies were divided into 3 equidistant zones (A, B, and C) from the superior to inferior endplates, and the positions of the screw tips were noted.

RESULTS

There were 41 men and 23 women (mean age = 45.5 years). A total of 428 screws were inserted. There were 2 cases of superior pedicle wall violation in D1 and D5. The majority (96.97%) of the pedicle screws were inserted into zones A and B.

CONCLUSIONS

We introduced a simple, accurate, and safe method of directing the sagittal inclination of the pedicle screw in the thoracic and lumbar spine without intraoperative image guidance.

The impact of robot-assisted spine surgeries on clinical outcomes: A systemic review and meta-analysis

BACKGROUND

Medical robotics has enabled a significant advancement in the field of modern spine surgery, especially in pedicle screw fixation. A plethora of studies focused on the accuracy of pedicle fixation in robotic-assisted (RA) technology. However, it is not clear whether RA techniques can improve patients' clinical outcomes.

METHODS

We retrieved relevant studies that compare the differences between RA and freehand (FH) techniques in spine surgeries from the following databases: PubMed, Embase, Cochrane Library and Web of Science. The perioperative outcomes of this technology were measured with parameters including radiation exposure, operative time, the length of hospital stay, complication rates and revision rates. Two reviewers independently reviewed the studies in our sample, assessed their validity and extracted relevant data.

RESULTS

Our search resulted in a sample of 23 eligible studies, which involved 1247 patients (5042 pedicle screws) in the RA group and 1273 patients (4830 pedicle screws) in the FH group. With regard to the radiation exposure, the fluoroscopy time was less in surgeries assisted by Mazor robots (standard mean difference [SMD] = -0.96, 95% CI = -1.60 to -0.31) but more in Tianji robots (SMD = 0.91, 95% CI = 0.17 to 1.66) and ROSA robots (SMD = 2.57, 95% CI = 2.01 to 3.13). For radiation dose, a decrease was observed in Tianji robots (SMD = -1.59, 95% CI = -2.13 to -1.05). In the lumbar subgroup, the use of robots increased the operative time (SMD = 0.53, 95% CI = 0.19 to 0.86). In the degenerative diseases (DG) group, there was a significant decrease in the length of hospital stay when robots were introduced (SMD = -0.30, 95% CI = -0.48 to -0.12). While in the DF (deformity) and DG group, a significant increase was found (SMD = 0.17, 95% CI = 0.02 to 0.32). The complication (OR = 0.41, 95% CI = 0.26 to 0.66) and the revision rates (OR = 0.38, 95% CI = 0.24 to 0.60) showed a significant decrease in the RA group compared to the conventional FH group.

CONCLUSIONS

This study suggests that RA spine surgeries would result in fewer complications, a lower revision rate and shorter length of hospital stay. As the technology continues to evolve, we may expect more applications of robotic systems in spine surgeries.

Freehand Trans-Perineal Biopsy in Chinese Patients With PSA < 20 ng/ml: Similar Cancer Detection Rate but Different Lesion Detection Rate

The present study aimed to investigate the diagnostic efficacy and the regional location of prostate cancer (PCa) as well as the accuracy of assessment between trans-perineal template-guided mapping biopsy (TTMB) and freehand trans-perineal biopsy (FTPB) for men with PSA < 20 ng/ml. Thus, we evaluated 623 consecutive patients with PSA < 20 ng/ml who had prostate biopsies in our institute between July 2017 and September 2018. Patients were divided into two groups based on different biopsy methods: 217 (34.83%) patients with TTMB and 406 (65.17%) with FTPB. Thirty six patients with TTMB and 80 with FTPB had continued undergone radical prostatectomy after a cancer diagnosis. Then the Gleason score of the biopsy and the post-radical prostatectomy specimens in each patient were compared. Overall, the PCa detection rate was 34.35%. There was no significant difference in PCa detection rate between TTMB and FTPB (35.48 vs. 33.74%, respectively; p = 0.663). Besides, the detection rate of significant PCa (Gleason score ≥ 7) in TTMB was 29.03% while FTPB was 23.89% (p = 0.162). The detection rate at the apex of the prostate was higher than the detection rate at the base of the prostate (9.80 vs. 5.79%; p < 0.01) when performing the TTMB. The FTPB would miss 10% of the positive diagnosis and almost half of the lesions. The upgraded of Gleason score from biopsy to post-radical prostatectomy was 16.67% with the TTMB and 36.25% with the FTPB (p = 0.034). The TTMB had a similar cancer detection rate, but a higher lesion detection rate and more accuracy in assess the actual Gleason score when comparing to FTPB for men with PSA < 20 ng/ml. By performing a 20-core TTMB, the cancer detection rate at the apex of the prostate was higher than the base.

Comparison of Freehand Sagittal Trajectories for Inserting Pedicle Screws Between C7 and T5

STUDY DESIGN

Anatomic study using computed tomographic scans.

OBJECTIVE

The purpose of this paper was to determine the trajectory of pedicle screw insertions, in regard to posterior bony landmarks encountered during standard posterior exposure of the spine between the seventh cervical (C7) and the fifth thoracic (T5) vertebrae, when lateral fluoroscopic and radiographic guidance may be obstructed by the scapula and shoulders.

SUMMARY OF BACKGROUND DATA

Only a few studies have evaluated the intraoperative sagittal trajectory of pedicle screw insertion.

MATERIALS AND METHODS

We assessed 64 participants of a health screening program using whole-spine computed tomographic scans. On the basis of 5 previously reported methods, we designed 3 freehand trajectories: lamina surface method (angle between the superior vertebral endplate and the surface of the lamina), spinous process method (angle between the superior vertebral endplate and a line connecting the tips of the index spinous process and the one cephalad to it), and facet tilt method (angle between the superior endplate and the superior facet tilt). We calculated each of the angles for the C7-T5 vertebrae and determined the most reliable method using coefficients of variation (CV) and intraobserver and interobserver reliability.

RESULTS

The lamina surface method had the smallest CVs for C7 and T1, and the mean angles were larger than 90 degrees (range, 94.7-102.4 degrees). The spinous process method had the smallest CVs between T2 and T5, and the mean angles were <90 degrees (range, 85.0-87.0 degrees). The intraobserver and interobserver reliabilities were good or excellent for both methods.

CONCLUSIONS

The ideal sagittal trajectories for pedicle screw insertion are nearly orthogonal to the lamina surface or the line connecting the spinous processes, but were different for each of the vertebrae. The lamina surface method was the most reliable for C7 and T1, whereas the spinous process method was most reliable between T2 and T5.

LEVEL OF EVIDENCE

Level III.

The posterior superior iliac spine and sacral laminar slope: key anatomical landmarks for freehand S2-alar-iliac screw placement

OBJECTIVE

The S2-alar-iliac (S2AI) screw is an increasingly popular method for spinopelvic fixation. The technique of freehand S2AI screw placement has been recently described. The purpose of this study was to demonstrate, through a CT imaging study of patients with spinal deformity, that screw trajectories based on the posterior superior iliac spine (PSIS) and sacral laminar slope result in reliable freehand S2AI trajectories that traverse safely above the sciatic notch.

METHODS

Fifty consecutive patients (age ≥ 18 years) who underwent primary spinal deformity surgery were included in the study. Simulated S2AI screw trajectories were analyzed with 3D visualization software. The cephalocaudal coordinate for the starting point was 15 mm cephalad to the PSIS. The mediolateral coordinate for the starting point was in line with the lateral border of the dorsal foramina. The cephalocaudal screw trajectory was perpendicular to the sacral laminar slope. Screw trajectories, lengths, and distance above the sciatic notch were measured.

RESULTS

The mean sagittal screw angle (cephalocaudal angulation) was 44.0° ± 8.4° and the mean transverse angle (mediolateral angulation) was 37.3° ± 4.3°. The mean starting point was 5.9 ± 5.8 mm distal to the caudal border of the S1 foramen. The mean screw length was 99.9 ± 18.6 mm. Screw trajectories were on average 8.5 ± 4.3 mm above the sciatic notch. A total of 97 of 100 screws were placed above the sciatic notch. In patients with transitional lumbosacral anatomy, the starting point on the lumbarized/sacralized side was 3.4 mm higher than on the contralateral unaffected side.

CONCLUSIONS

The PSIS and sacral laminar slope are two important anatomical landmarks for freehand S2AI screw placement.

Utilization of the 3D-printed spine model for freehand pedicle screw placement in complex spinal deformity correction

Background

We aim to demonstrate the safety and efficacy of utilizing 3D-printed spine models to facilitate freehand pedicle screw placement in complex spinal deformity correction. Currently there is no data on using 3D-printed models for freehand pedicle screw placement spinal deformity correction.

Methods

All patients undergoing spinal deformity correction over a 16-month period (September 2015 - December 2016) at the Spine Hospital of Columbia University Medical Center by the senior surgeon were reviewed. 3D-printed spine models were used to facilitate intraoperative freehand pedicle screw placement in patients with severe spinal deformities. Intraoperative O-arm imaging was obtained after pedicle screw placement in all patients. Screws were graded as intrapedicular, <2 mm breach, 2-4 mm breach, and >4 mm breach; anterior breaches >4 mm were also recorded. Screw accuracy was compared to a historical cohort (not using 3D-printed models) using SPSS 23.0 (Chicago, IL, USA).

Results

A total of 513 freehand pedicle screws were placed from T1 to S1 in 23 patients. Overall, 494 screws (96.3%) were placed in acceptable positions according to the pre-operative plan, which had no statistically significant difference (P=0.99) compared to a historical cohort with less severe deformities. There were 84.2% screw that were intrapedicular or <2 mm breach; among the 81 screws (15.8%) with >2 mm breach, 67 were lateral breaches (most are intended juxtapedicular placement), whereas 14 were medial breaches. There were 11 screws (2.1%) that required repositioning due to pedicle violation, and eight screws (1.6%) had >4 mm anterior breach and required shortening. There was no neuromonitoring change or any other complications directly or indirectly related to freehand pedicle screw placement.

Conclusions

The 3D-printed spinal model can make freehand pedicle screw placement safer in severe spinal deformity cases with acceptable accuracy, and no neurological or vascular complications.

Image guidance and improved accuracy of external ventricular drain tip position particularly in patients with small ventricles

OBJECTIVEExternal ventricular drain (EVD) insertion is one of the most common emergency neurosurgical procedures. EVDs are traditionally inserted freehand (FH) in an emergency setting, but often result in suboptimal positioning. Image-guided surgery (IGS) is selectively used to assist placement. However, the accuracy and practicality of IGS use is yet to be reported. In this study, the authors set out to assess if IGS is practical and improves the accuracy of EVD placement.METHODSCase notes and images obtained in patients who underwent frontal EVD placement were retrospectively reviewed. Ventriculomegaly was determined by the measurement of the Evans index. EVD location was classified as optimal (ipsilateral frontal horn) or suboptimal (any other location). Propensity score matching of the two groups (IGS vs FH) for the Evans index was performed. Data were analyzed for patient age, diagnosis, number of EVDs, and complications. Those without postoperative CT scans were excluded.RESULTSA total of 607 patients with 760 EVDs placed were identified; 331 met inclusion criteria. Of these, 287 were inserted FH, and 44 were placed with IGS; 60.6% of all unmatched FH EVDs were optimal compared with 75% of the IGS group (p = 0.067). The IGS group had a significantly smaller Evans index (p < 0.0001). Propensity score matching demonstrated improved optimal position in the IGS group when compared with the matched FH group (75% vs 43.2%, OR 4.6 [1.5-14.6]; p = 0.002). Patients with an Evans index of ≥ 0.36 derived less benefit (75% in IGS vs 66% in FH, p = 0.5), and those with an Evans index < 0.36 derived more benefit (75% in IGS vs 53% in FH, p = 0.024). The overall EVD complication rate was 36% in the FH group versus 18% in the IGS group (p = 0.056). Revision rates were higher in the FH group (p = 0.035), and the operative times were similar (p = 0.69). Long intracranial EVD catheters were associated with tip malposition irrespective of the group.CONCLUSIONSImage guidance is practical and improves the accuracy of EVD placement in patients with small ventricles; thus, it should be considered for these patients.

Utilizing preprocedural CT scans to identify patients at risk for suboptimal external ventricular drain placement with the freehand insertion technique

OBJECTIVEFreehand insertion of external ventricular drains (EVDs) using anatomical landmarks is considered the primary method for placement, although alternative techniques have shown improved accuracy in positioning. The purpose of this study was to retrospectively evaluate which features of the baseline clinical history and preprocedural CT scan predict EVD positioning into suboptimal and unsatisfactory locations when using the freehand insertion technique.METHODSA retrospective chart review was performed evaluating 189 consecutive adult patients who received an EVD via freehand technique through an anterior burr hole between January 1, 2014, and December 31, 2015, at a Level 1 trauma facility in Edmonton, Alberta, Canada. The primary outcome measures included features associated with suboptimal positioning (Kakarla grade 1 vs Kakarla grades 2 and 3). The secondary outcome measures were features associated with unsatisfactory positioning (Kakarla grades 1 and 2 vs Kakarla grade 3).RESULTSFifty-one EVDs (27%) were suboptimally positioned. Fifteen (8%) EVDs were placed into eloquent cortex or nontarget CSF spaces. Admitting diagnosis, head height-to-width ratio in axial plane, and side of predominant pathology were found to be significantly associated with suboptimal placement (p = 0.02, 0.012, and 0.02, respectively). A decreased height-to-width ratio was also associated with placement into only eloquent cortex and/or nontarget CSF spaces (p = 0.003).CONCLUSIONSFreehand insertion of an EVD is associated with significant suboptimal positioning into parenchyma and nontarget CSF spaces. The likelihood of inaccurate EVD placement can be predicted with baseline clinical and radiographic features. The patient's height-to-width ratio represents a novel potential radiographic predictor for malpositioning.

Use of 3D Navigation in Subaxial Cervical Spine Lateral Mass Screw Insertion

Objective  Cervical spine can be stabilized by different techniques. One of the common techniques used is the lateral mass screws (LMSs), which can be inserted either by freehand techniques or three-dimensional (3D) navigation system. The purpose of this study is to evaluate the difference between the 3D navigation system and the freehand technique for cervical spine LMS placement in terms of complications. Including intraoperative complications (vertebral artery injury [VAI], nerve root injury [NRI], spinal cord injury [SCI], lateral mass fracture [LMF]) and postoperative complications (screw malposition, screw complications).

Methods  Patients who had LMS fixation for their subaxial cervical spine from January 2014 to April 2015 at the Ottawa Hospital were included. A total of 284 subaxial cervical LMS were inserted in 40 consecutive patients. Surgical indications were cervical myelopathy and fractures. The screws' size was 3.5 mm in diameter and 8 to 16 mm in length. During the insertion of the subaxial cervical LMS, the 3D navigation system was used for 20 patients, and the freehand technique was used for the remaining 20 patients. We reviewed the charts, X-rays, computed tomography (CT) scans, and follow-up notes for all the patients pre- and postoperatively.

Results  Postoperative assessment showed that the incidence of VAI, SCI, and NRI were the same between the two groups. The CT scan analysis showed that the screw breakage, screw pull-outs, and screw loosening were the same between the two groups. LMF was less in the 3D navigation group but statistically insignificant. Screw malposition was less in the 3D navigation group compared with the freehand group and was statistically significant. The hospital stay, operative time, and blood loss were statistically insignificant between the two groups.

Conclusions  The use of CT-based navigation in LMS insertion decreased the rate of screw malpositions as compared with the freehand technique. Further investigations and trials will determine the effect of malpositions on the c-spine biomechanics. The use of navigation in LMS insertion did not show a significant difference in VAI, LMF, SCI, or NRI as compared with the freehand technique.

Robot-assisted vs freehand pedicle screw fixation in spine surgery - a systematic review and a meta-analysis of comparative studies

BACKGROUND

Medical robotics has progressively become more compelling in modern orthopaedic surgery. Several studies comparing robot-assisted (RA) and freehand (FH) conventional techniques for pedicle screw fixation have been published, but the results are unclear. Here, we assessed current evidence regarding the efficiency, safety and accuracy of RA compared with FH techniques.

METHODS

A literature search of PubMed, Embase, the Cochrane Library and Web of Science was performed to compare the differences between RA and FH in spine surgery. Two reviewers independently reviewed included studies, conducted a risk of bias assessment, and extracted data.

RESULTS

Three randomized controlled trials (RCTs) and six retrospective comparative studies included a total of 750 patients (3625 pedicle screws). No significant differences were noted between RA and FH in pedicle screw accuracy (95.5% compared with 92.9%; odds ratio: 1.35; 95% confidence interval [CI], 0.55 to 3.30; P=0.51), overall complication rate (1.33% compared with 3.45%; odds ratio: 0.46; 95% CI, 0.15 to 1.43; P=0.18) and radiation exposure time (weighted mean difference [WMD]:8.49; 95% CI, -15.43 to 32.40; P=0.49). While RA was associated with a longer operative time (WMD: 39.63; 95% CI, 5.27 to 73.99; P= 0.02), percutaneous or minimal robot-assisted pedicle screw fixation (M-RA) had a shorter radiation exposure time than FH (WMD: -33.10; 95% CI, -38.18 to -28.02; P=0.00) CONCLUSIONS: The current literature did not prove that RA supersedes FH, although several studies are more optimistic about this procedure. Future well-designed RCTs assessing RA and FH are needed to confirm and update the findings of this analysis.

Freehand technique with the predrilled hole method for ulnar-shortening osteotomy

BACKGROUND

Ulnar shortening is a common and useful method for treating ulnar wrist pain from many causes. Many devices used to perform osteotomy have been introduced in the literature; however, the devices are not universally available. The standard freehand technique is still commonly used in clinical practice; however, it is associated with several complications and is time-consuming. We present a freehand technique for ulnar-shortening osteotomy using a predrilled hole method.

METHODS

From 2011 to 2013, we performed the predrilled hole method for ulnar shortening in 18 cases using the six-hole limited-contact dynamic compression plate (LC-DCP) and in two cases using the Acumed six-hole Locking Midshaft Ulna Plate.

RESULTS

All patients had uneventful union, and the average operative time was 39.7 minutes (range, 32-50 minutes). The average follow-up period was 21 months (range, 12-30 months). There were no complications except in three patients in the LC-DCP group who complained of implant irritation. Good functional outcomes were achieved with this method.

CONCLUSION

Our technique is easy and quick to use and can minimize soft-tissue manipulation. The union rate is high and complications are few.

A comparative study of pedicle screw fixation in dorsolumbar spine by freehand versus image-assisted technique: A cadaveric study

BACKGROUND

New and expensive technology such as three-dimensional computer assisted surgery is being used for pedicle screw fixation in dorsolumbar spine. Their availability, expenses and amount of radiation exposure are issues in a developing country. On the contrary, freehand technique of pedicle screw placement utilizes anatomic landmarks and tactile palpation without fluoroscopy or navigation to place pedicle screws. The purpose of this study was to analyze and compare the accuracy of freehand and image-assisted technique to place pedicle screws in the dorsolumbar spine of cadavers by an experienced surgeon and a resident. Evaluation was done using dissection of pedicle and computed tomography (CT) imaging.

MATERIALS AND METHODS

Ten cadaveric dorsolumbar spines were exposed by a posterior approach. Titanium pedicle screws were inserted from D5 to L5 vertebrae by freehand and image-assisted technique on either side by an experienced surgeon and a resident. CT was obtained. A blinded radiologist reviewed the imaging. The spines were then dissected to do a macroscopic examination. Screws, having evidence of cortical perforation of more than 2 mm on CT, were considered to be a significant breach.

RESULTS

A total of 260 pedicle screws were placed. The surgeon and the resident placed 130 screws each. Out of 130 screws, both of them placed 65 screws each by freehand and image- assisted technique each. The resident had a rate of 7.69% significant medial and 10.76% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 9.23% significant lateral breach. The expert surgeon had a rate of 6.15% significant medial and 1.53% significant lateral breach with freehand technique while with image-assisted had a rate of 3.07% significant medial and 6.15% significant lateral breach on CT evaluation.

CONCLUSION

Freehand technique is as good as the image-assisted technique. Under appropriate supervision, residents can safely learn to place freehand pedicle screws with an acceptable violation rate.

Axial relationship between dental implants and teeth/implants: a radiographic study

The relationship of dental implants with neighboring teeth will affect both occlusal relationship and distribution of forces; thus, the purpose of this study was to examine implants' axial relationship with adjacent and opposing teeth/implants. Data of dental implants patients was retrieved. Panoramic X rays were digitized. Computer-based software was used to measure the angular relationship between the implants and adjacent/opposing teeth and implants. Data was further sorted by the mode of placement and implants position. 50 patients (219 implants) were included. Mean angle to adjacent tooth/implant was 178.71° ± 9.18° (range 129.7°-206°). Implants were more parallel to adjacent teeth (180.99° ± 1.06°) than to adjacent implants (176.32° ± 0.54°; P = .0001). Mean angular relationship to opposite tooth was 167.88° ± 8.92° (range 137.7°-179.8°). Implants that were placed freehand or with positional guide had similar intra-arch relationship (178.22° and 178.81°, respectively) and similar inter-arch angulations (164.46° and 167.74°). Molars had greater deviation of the angular relationship (175.54°) compared to premolars (181.62°) and incisors (180.55°, P = .0001). Implants placed in the maxilla had smaller axial deviation compared to implants in the mandible (180.41° ± 0.64 vs 177.14° ± 1.02; P = .0081). Good axial relationship may be obtained in most implants placed by an experienced clinician, even when placed freehand. The mandibular posterior region is more prone to axial deviation and as such requires special attention.