Return to Driving Is Safe 6 Weeks After Anterior Cervical Surgery for Symptomatic Cervical Degenerative Disc Disease.

STUDY DESIGN: Prospective Cohort Study. OBJECTIVES: This study aims to determine the timing and clinical parameters for a safe return to driving. SUMMARY OF BACKGROUND DATE: Returning to driving after cervical spine surgery remains a controversial topic, with no clear consensus on how to best assess a patient's fitness to drive. Previous studies using brake reaction time or subjective questionnaires recommend a return to driving 6 weeks after surgery. METHODS: Patients above 18 years of age who underwent anterior cervical spine surgery for symptomatic cervical degenerative disk disease and possessed a valid motorcar driving license were recruited from 2018 to 2020. Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) scores, range of motion, and functional strength of the cervical spine were collected preoperatively and at 2-, 4-, 6- and 12 weeks postsurgery. Patients underwent a standard functional driving assessment protocol at the institution to determine their fitness to drive. This comprised of a clinic-based off-road screening tests and on-road driving test in a real-world environment. RESULTS: Twenty-one patients were recruited. The mean age was 56.6±8.9 years. Eighty-one percent of the patients passed the on-road driving assessment at 6 weeks. Patients who passed the driving assessment had lower mean NDI scores, 3.4±3.1 versus 10.8±8.0 ( P =0.006), and higher mean mJOA scores 16.1±0.6 versus 15.0±1.8 ( P =0.045). Patients who passed the driving assessment also had higher functional cervical flexor strength, 21.1s±5.8s versus 13.0s±10.2s ( P =0.042) in a supine position but not correlated with a range of motion of the spine in all directions. CONCLUSION: Most patients undergoing single or dual-level anterior cervical surgery for symptomatic cervical degenerative disk disease demonstrate the ability to pass a standardized driving assessment and are safe to return to driving more than 6 weeks after surgery. Driving ability appears to be correlated with NDI scores ≤3 ( P =0.006), mJOA scores ≥16 ( P =0.045), and cervical flexion endurance of ≥21s ( P =0.042). LEVEL OF EVIDENCE: Level II.

Spinal Navigation for Cervical Pedicle Screws: Surgical Pearls and Pitfalls.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: We intend to evaluate the accuracy and safety of cervical pedicle screw (CPS) insertion under O-arm-based 3-dimensional (3D) navigation guidance. METHODS: This is a retrospective study of patients who underwent CPS insertion under intraoperative O-arm-based 3D navigation during the years 2009 to 2018. The radiological accuracy of CPS placement was evaluated using their intraoperative scans. RESULTS: A total of 297 CPSs were inserted under navigation. According to Gertzbein classification, 229 screws (77.1%) were placed without any pedicle breach (grade 0). Of the screws that did breach the pedicle, 51 screws (17.2%) had a minor breach of less than 2 mm (grade 1), 13 screws (4.4%) had a breach of between 2 and 4 mm (grade 2), and 4 screws (1.3%) had a complete breach of 4 mm or more (grade 3). Six screws were revised intraoperatively. There was no incidence of neurovascular injury in this series of patients. 59 of the 68 breaches (86.8%) were found to perforate laterally, and the remaining 9 (13.2%) medially. It was noted that the C5 cervical level had the highest breach rate of 33.3%. CONCLUSIONS: O-arm-based 3D navigation can improve the accuracy and safety of CPS insertion. The overall breach rate in this study was 22.9%. Despite these breaches, there was no incidence of neurovascular injury or need for revision surgery for screw malposition.

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

STUDY DESIGN: Retrospective review. PURPOSE: To determine the accuracy of thoracolumbar pedicle screw insertion with the routine use of three-dimensional (3D) intraoperative imaging and navigation over a large series of screws in an Asian population. OVERVIEW OF LITERATURE: The use of 3D intraoperative imaging and navigation in spinal surgery is aimed at improving the accuracy of pedicle screw insertion. This study analyzed 2,240 pedicle screws inserted with the routine use of intraoperative navigation. It is one of very few studies done on an Asian population with a large series of screws. METHODS: Patients who had undergone thoracolumbar pedicle screws insertion using intraoperative imaging and navigation between 2009 and 2017 were retrospectively analyzed. Computed tomography (CT) images acquired after the insertion of pedicle screws were analyzed for breach of the pedicle wall. The pedicle screw breaches were graded according to the Gertzbein classification. The breach rate and revision rate were subsequently calculated. RESULTS: A total of 2,240 thoracolumbar pedicle screws inserted under the guidance of intraoperative navigation were analyzed, and the accuracy of the insertion was 97.41%. The overall breach rate was 2.59%, the major breach rate was 0.94%, and the intraoperative screw revision rate was 0.7%. There was no incidence of return to the operating theater for revision of screws. CONCLUSIONS: The routine use of 3D navigation and intraoperative CT imaging resulted in consistently accurate pedicle screw placement. This improved the safety of spinal instrumentation and helped in avoiding revision surgery for malpositioned screws.

Prospective Evaluation of the Time Required for Insertion of 380 Lumbar and Sacral Pedicle Screws Using Navigation with an Intraoperative 3-Dimensional Imaging System.

BACKGROUND: The aim of this study was to evaluate the time required for various parts of the procedure to insert lumbar and sacral pedicle screws using navigation with an intraoperative, 3-dimensional imaging system. Comparison of these timings was carried out for different surgical indications. METHODS: This was a single-surgeon prospective cohort study of 69 consecutive patients (between August 2013 and June 2018) who underwent insertion of 380 pedicle screws into the lumbar and sacral vertebrae. Surgical indications, average time required for surgical exposure and attachment of the reference frame, average time required until completion of the first pedicle screw insertion, and average time required for insertion of a single pedicle screw were evaluated. RESULTS: The average time required from skin incision to reference frame attachment was 28.3 ± 20.4 (mean ± SD) minutes, and the average time required from reference frame attachment to completion of first pedicle screw insertion was 22.3 ± 9.6 minutes. The average time required for insertion of a single pedicle screw was 7.8 ± 2.7 minutes. When surgical indications were compared, the average time required for insertion of a single pedicle screw was 7.7 ± 2.6 minutes in surgery for spondylosis-related stenosis, 8.1 ± 2.8 minutes for degenerative scoliosis, and 8.2 ± 3.6 minutes for metastatic tumor (P = .89). There were no significant changes in these timings over consecutive 6-month periods. CONCLUSIONS: There is no significant learning curve and no significant difference in navigation setup and pedicle screw insertion timings with intraoperative 3-dimensional navigation systems for surgeries of different pathologies and levels of surgery. LEVEL OF EVIDENCE: 2.

Reliability of the new modified Moro's classification and oblique corridor grading to assess the feasibility of oblique lumbar interbody fusion.

INTRODUCTION: The modified Moro's classification (MMC) of psoas morphology and oblique corridor (OC) grading were recently proposed. Their reliability needs to be tested. METHODS: T2 weighted lumbar disc level axial-cut MRI images of patients with degenerative spondylosis were distributed to five spine surgeons. The inter and intra-rater reliability of MMC and OC grading were calculated based on their ratings. RESULTS: Based on kappa statistics, we inferred that both MMC and OC grading are reliable measures. CONCLUSION: Both MMC and OC grading, in combination, can be used to predict the feasibility of oblique lumbar interbody fusion and aid in patient selection.

The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws.

STUDY DESIGN: A retrospective study of radiographic parameters of patients who underwent lumbar spinal pedicle screw insertion. PURPOSE: The optimal length of pedicle screws is often determined by the lateral radiograph during minimally invasive surgery (MIS). Compared with open techniques, measuring the precise length of screws or assessing the cortical breach is challenging. This study aims to ascertain the optimal pedicle screw lengths on intraoperative lateral radiographs for L1-L5. OVERVIEW OF LITERATURE: Research has revealed that optimal pedicle screw length is essential to optimize fixation, especially in osteoporotic patients; however, it must be balanced against unintentional breach of the anterior cortex, risking injury to adjacent neurovascular structures as demonstrated by case reports. METHODS: We reviewed intra- and postoperative computed tomography scans of 225 patients who underwent lumbar pedicle screw insertion to ascertain which of the inserted screws were 'optimal screws.' The corresponding lengths of these screws were analyzed on postoperative lateral radiographs to ascertain the ideal position that a screw should attain (expressed as a percentage of the entire vertebral body length). RESULTS: We reviewed 880 screws of which 771 were optimal screws. We noted a decreasing trend in average optimal percentages of insertion into the vertebral body for pedicle screws going from L1 (average=87.60%) to L5 (average=78.87%). The subgroup analysis revealed that there was an increasing percentage of screws directed in a straight trajectory from L1 to L5, compared to a medially directed trajectory. CONCLUSIONS: During MIS pedicle screw fixation, this study recommends that pedicle screws should not exceed 85% of the vertebral body length on the lateral view for L1, 80% for L2-L4, and 75% for L5; this will minimize the risk of anterior cortical breach yet maximize pedicle screw purchase for fixation stability.

Spinal Navigation during Orthopedic Residency Training: A Double-Edged Sword?

BACKGROUND: Orthopedic residents in our institute have the opportunity to participate in navigation-assisted spine surgery during their residency training. This paves the way for a new dimension of learning spine surgery, which the previous generation was not exposed to. To study this in detail, we conducted a cross-sectional descriptive survey among our residents to analyse their perception, understanding, and competency regarding pedicle screw application using spinal navigation. METHODS: We selected orthopedic residents (n = 20) who had completed 3 years of training that included at least one rotation (4-6 months) in our spine division. They were asked to respond to a four-part questionnaire that included general and Likert scale-based questions. The first two parts dealt with various parameters regarding spinal navigation and free-hand technique for applying pedicle screws. The third part dealt with residents' opinion regarding the advantages and disadvantages of spinal navigation. The final part was an objective analysis of residents' ability to identify the pedicle screw entry points in selected segments. RESULTS: We found that our residents were better trained to apply pedicle screws using spinal navigation. The mean Likert scale score for perception regarding their competency to apply pedicle screws using spinal navigation was 3.65 ± 0.81, compared to only 2.8 ± 0.77 when using the free-hand technique. All residents agreed that spinal navigation is an excellent teaching tool with higher accuracy and greater utility in anatomically critical cases. However, 35% of the residents were not able to identify the entry points correctly in the given segments. CONCLUSIONS: All selected residents were perceived to be competent to apply pedicle screws using spinal navigation. However, some of them were not able to identify the entry points correctly, probably due to overreliance on spinal navigation. Therefore, we encourage residents to concentrate on surface anatomy and tactile feedback rather than completely relying on the navigation display monitor during every screw placement. In addition, incorporating cadaveric and saw bone workshops as a part of teaching program can enhance better understanding of surgical anatomy.

Factors Impacting Mortality in Geriatric Patients with Acute Spine Fractures: A 12-Year Study of 613 Patients in Singapore.

Study Design: Retrospective database analysis. Purpose: To identify risk factors that predict mortality following acute spine fractures in geriatric patients of Singapore. Overview of Literature: Acute geriatric spinal fractures contribute significantly to local healthcare costs and hospital admissions. However, geriatric mortality following acute spine fractures is scarcely assessed in the Asian population. Methods: Electronic records of 3,010 patients who presented to our hospital's emergency department and who were subsequently admitted during 2004-2015 with alleged history of traumatic spine fractures were retrospectively reviewed, and 613 patients (mean age, 85.7±4.5 years; range, 80-101 years; men, 108; women, 505) were shortlisted. Mortality rates were reviewed up to 1 year after admission and multivariate analyses were performed to identify independent risk factors correlating with mortality. Results: Women were more susceptible to spine fractures (82.4%), with falls (77.8%) being the most common mechanism of injury. Mortality rates were 6.0%, 8.2%, and 10.4% at 3, 6, and 12 months, respectively. The most common causes of death at all 3 time points were pneumonia and ischemic heart disease. Based on the multivariate analysis at 1-year follow-up, elderly women had a lower mortality rate compared to men (p<0.001); mortality rates increased by 6.3% (p=0.024) for every 1-year increase in the patient's age; and patients with an American Spinal Injury Association (ASIA) score of A-C had a much higher mortality rate compared to those with an ASIA score of D-E (p<0.001). Conclusions: An older age at presentation, male sex, and an ASIA score of A-C were identified as independent factors predicting increased mortality among geriatric patients who sustained acute spine fractures. The study findings highlight at-risk groups for acute spine fractures, thereby providing an opportunity to develop strategies to increase the life expectancy of these patients.

Routine spinal navigation for thoraco-lumbar pedicle screw insertion using the O-arm three-dimensional imaging system improves placement accuracy.

Modern image-guided spinal navigation employs high-quality intra-operative three dimensional (3D) images to improve the accuracy of spinal surgery. This study aimed to assess the accuracy of thoraco-lumbar pedicle screw insertion using the O-arm (Breakaway Imaging, LLC, Littleton, MA, USA) 3D imaging system. Ninety-two patients underwent insertion of thoraco-lumbar pedicle screws guided by O-arm navigation over a 27 month period. Intra-operative scans were retrospectively reviewed for pedicle breach. The operative time of patients where O-arm navigation was used was compared to a matched control group where fluoroscopy was used. A total of 467 pedicle screws were inserted. Four hundred and forty-five screws (95.3%) were placed within the pedicle without any breach (Gertzbein classification grade 0). Sixteen screws (3.4%) had a pedicle breach of less than 2mm (Gertzbein classification grade 1), and six screws (1.3%) had a pedicle breach between 2mm and 4mm (Gertzbein classification grade 2). The grade 2 screws were revised intra-operatively. There was no incidence of neurovascular injury in this series of patients. The mean operative time for O-arm patients was 5.25 hours. In a matched control group of fluoroscopy patients, the mean operative time was 4.75 hours. The difference in the mean operative time between the two groups was not statistically significant (p=0.15, paired t-test). Stereotactic navigation based on intra-operative O-arm 3D imaging resulted in high accuracy in thoraco-lumbar pedicle screw insertion.