Correlating SPECT-CT activity in lumbar facet joints with response to lumbar medial branch and L5 dorsal ramus blocks.

Introduction: Lumbar facet arthritis is a significant source of back pain and impaired function that is amenable to treatment with medial branch radiofrequency neurotomy (RFN). Identifying appropriate patients for this treatment requires integration of information from the history, physical exam, and diagnostic imaging, but the current diagnostic standard for facet-mediated pain is positive comparative medial branch blocks (MBBs). Lumbar SPECT-CT has recently been evaluated as a potential predictor of positive MBBs with mixed results. The purpose of this retrospective analysis was to determine if the level of concordance between SPECT-CT uptake and facet joints targeted with MBB was associated with a positive block. Methods: A retrospective review was performed to identify all patients undergoing lumbar MBB within 12 months after having a lumbar SPECT-CT. Each procedure was classified into one of four categories based on the level of concordance between facet joints demonstrating increased 99mTc uptake on SPECT-CT and those being blocked: 1) Complete Concordance (all joints demonstrating increased uptake were blocked and no additional joints blocked); 2) Partial Concordance (all joints demonstrating increased uptake were blocked, with at least one joint not demonstrating increased uptake blocked); 3) Partial Discordance (at least one but not all joints demonstrating increased uptake were blocked); 4) Complete Discordance (all blocks performed at joints not demonstrating increased uptake). Statistical analysis was performed to determine if the level of concordance between increased uptake on SPECT-CT and joints undergoing MBB was associated with a positive block using cutoffs of 50 % and 80 % pain relief. Results: A total of 180 procedures were analyzed (23 % Complete Concordance, 22 % Partial Concordance, 31 % Partial Discordance, 24 % Complete Discordance) and all groups demonstrated improvement in pain Numeric Rating Scale (NRS) scores. There was no significant association between level of concordance and having a positive block using thresholds of 50 % pain relief, χ 2(3, N = 180) = 4.880, p = .181; or 80 % pain relief, χ 2(3, N = 180) = 1.272, p = .736. Conclusion: SPECT-CT findings do not accurately predict positive lumbar MBB but may provide valuable information that can be considered with other factors when deciding which joints to treat.

Correlating SPECT-CT activity in cervical facet joints with positive response to cervical medial branch blocks.

Introduction: Cervical facet arthritis is a significant source of neck pain and impaired function that is amenable to treatment with medial branch radiofrequency neurotomy (RFN). Identifying appropriate patients for this treatment requires integration of information from the history, physical exam and diagnostic imaging, but the current diagnostic standard for facet-mediated pain is positive comparative medial branch blockade (MBB). SPECT-CT has recently been evaluated as a potential predictor of positive medial branch blocks with mixed results. The purpose of this retrospective analysis was to determine if a relationship exists between increased uptake on SPECT-CT of a given cervical facet joint and a positive MBB. Methods: A retrospective review was performed to identify all patients undergoing cervical MBB within 12 months after having a cervical SPECT-CT. Each procedure was categorized as either Concordant (all facet joints demonstrating increased 99mTc uptake on SPECT-CT were blocked) or Discordant (at least one facet joint demonstrating increased 99mTc uptake on SPECT-CT was not blocked or block was performed in a patient that had no increased uptake on SPECT-CT). Statistical analysis was performed to determine if concordance between facet joints demonstrating increased uptake on SPECT-CT and those undergoing MBB was associated with a positive block using cutoffs of 50% and 80% pain relief. Results: A total of 43 procedures were analyzed (25% Concordant, 75% Discordant) and both groups demonstrated improvement in pain Numeric Rating Scale (NRS) scores. No significant association between concordance and positive MBB was identified at thresholds of 50% (p = .481) and 80% (p = 1.000) pain relief. Conclusion: SPECT-CT findings do not accurately predict positive cervical MBB but may provide valuable information that can be considered with other factors when deciding which joints to treat.

Best of Both Worlds: Use of Robotic Principles for Placing Navigated Cervical and Difficult Upper Thoracic Pedicle Screws, a Technical Nuance.

Navigated pedicle screw placement can be particularly challenging for cervical and upper thoracic levels in obese patients. This technical challenge can be compounded by smaller-diameter tools, which can be flexible and therefore confound navigation. It is imperative to avoid excessive manipulation of surrounding tissues to maintain navigation accuracy in the mobile cervical spine.1 Robotic-assisted spinal approaches use firm guides to aid drilling and screw placement but are hindered by high costs with equipment acquisition.2,3 Here, we propose a technical nuance that combines robotic surgical principles with tools that are more readily available in many surgical departments (Video 1). We present the case of a 64-year-old woman with a chief complaint of neck pain, irradiating to the left worse than right arm and prior history of C5-7 anterior cervical diskectomy and fusion. Imaging showed multilevel degenerative disease and a solid prior C5-7 anterior cervical diskectomy and fusion with grade I anterolisthesis at C7-T1 due to severe facet degeneration with severe left-sided foraminal stenosis. Given failure of conservative management, the patient was brought to the operating room for left C7-T1 foraminotomy and C7-T1 posterior instrumented fusion. Here, we show the use of a tubular retractor fixed to the surgical bed for solid and reproducible trajectory for all tools to minimize the risk of surrounding tissue manipulation and its effect on navigation accuracy.

Single-Photon Emission Computed Tomography (SPECT-CT) as a Predictor of Pain Generators in Patients Undergoing Anterior Cervical Discectomy and Fusion (ACDF) for Axial Cervical Pain.

BACKGROUND: Axial neck pain is often associated with cervical instability, and surgical options are often reserved for patients with either neurological compromise or deformity of the spine. However, cervical facet arthropathy is often implicated with instability and the location of painful generators is often difficult to ascertain. Single-photon emission computed tomography (SPECT-CT) presents an adjunct to conventional imaging in the workup of patients with suspected facetogenic pain. We aimed to report our experience with patients undergoing anterior cervical discectomy and fusion (ACDF) guided by SPECT-CT for axial cervical pain. METHODS: We retrospectively identified all cases undergoing ACDF that presented with axial neck pain where correlating SPECT-CT high metabolism areas were identified. Patients were treated at a tertiary care institution between January 2018 and January 2021. Patients with positive radiotracer uptake pre-operatively were compared with patients undergoing ACDF without uptake on SPECT-CT. The pre- and post-operative patients who reported neck pain at one year were compared. RESULTS: Thirty-five patients were included in this retrospective cohort. The median pre- and post-intervention (at one-year follow-up) visual analog score (VAS) of patients undergoing ACDF without uptake on SPECT-CT was 7 and 3 (p<0.01), while the pre- and post-VAS for patients undergoing surgery with positive uptake on SPECT-CT was 8.5 and 0 (p<0.01). Improvement was significantly larger for patients undergoing SPECT-CT-guided ACDF (p=0.02). At one year after surgery, none of the assessed patients required additional surgical intervention. CONCLUSION: This case series represents the experience of our group to date with patients undergoing SPECT-CT-guided ACDF with results suggesting potential benefit in guiding fusion.

Frailty as a Predictor of Postoperative Morbidity and Mortality in Patients Aged 80 Years and Older Undergoing Instrumented Fusion.

BACKGROUND AND OBJECTIVES: Degenerative spine disease is a leading cause of disability, with increasing prevalence in the older patients. While age has been identified as an independent predictor of outcomes, its predictive value is limited for similar older patients. Here, we aimed to determine the most predictive frailty score of adverse events in patients aged 80 and older undergoing instrumented lumbar fusion. METHODS: We proceeded with a multisite (3 tertiary academic centers) retrospective review including patients undergoing instrumented fusion aged 80 and older from January 2010 to present. A composite end point encompassing 30-day return to operating room, readmission, and mortality was created. We estimated the area under the receiver operating characteristic curve for frailty scores (Modified Frailty Index-5 [MFI-5], Modified Frailty Index-11 [MFI-11], and Charlson Comorbidity Index [CCI]) in relation to that composite score. In addition, we estimated the association between each score and the composite end point by means of logistic regression. RESULTS: A total of 153 patients with an average age of 85 years at the time of surgery were included. We observed a 30-day readmission rate of 11.1%, reoperation of 3.9%, and mortality of 0.6%. The overall rate of the composite end point at 30 days was 25 (15.1%). The AUC for MFI-5 was 0.597 (0.501-0.693), for MFI-11 was 0.620 (0.518-0.723), and for CCI was 0.564 (0.453-0.675). The association between the scores and composite end point did not reach statistical significance for MFI-5 (odds ratio [OR] = 1.45 [0.98-2.15], P = .061) and CCI (OR = 1.13 [0.97-1.31], P = .113) but was statistically significant for MFI-11 (OR = 1.46 [1.07-2.00], P = .018). CONCLUSION: This is the largest study comparing frailty index scores in octogenarians undergoing instrumented lumbar fusion. Our findings suggest that while MFI-11 score correlated with adverse events, the predictive ability of existing scores remains limited, highlighting the need for better approaches to identify select patients at age extremes.

Transient Neuropathic Pain Following Mechanically Assisted Manipulation of the Spine: A Clinical Case Study.

We describe the case of a patient developing acute neuropathic pain in the sciatic nerve distribution following spinal manipulation. Manipulative treatment with an Activator Adjusting Instrument (AAI) was recommended and performed. Within 24 hours, the patient developed severe 10/10 pain originating from the left gluteal area at the site of one of the activator deployments with radiation all the way down his left leg to the foot. He was able to maintain distal left leg strength and sensation. Relief was achieved with subsequent physical therapy techniques to relax his deep gluteal muscles, raising the hypothesis of temporary injury to the deep gluteal muscles, with painful contractions resulting in gluteal region pain as well as sciatic nerve inflammation as the nerve passed through that region. This clinical case illustrates some of the perils and risks of spinal manipulation, particularly in the elderly, and the need for careful patient selection.

Hybrid Minimally Invasive Endoscopic Approach for Gaseous Protrusion Causing L5 Radiculopathy.

We present an illustrative case of a hybrid approach between minimally invasive and endoscopic spine surgery techniques. We utilized this hybrid approach for the first 3 cases to help diminish the learning curve as we started a spinal endoscopy program. The patient is an 85-year-old woman with a prior history of arthrodesis at L3-5. She presented with severe leg pain and imaging evidence of degenerative disk disease with disk protrusion in the extraforaminal zone at L5-S1. Computed tomography imaging shows the disk protrusion to be gaseous in nature. Given failure of conservative management and patient refusal for extension of her prior fusion, she was offered a combined minimally invasive navigated technique and endoscopic approach for far lateral diskectomy. After obtaining the correct trajectory, with confirmation by intraoperative fluoroscopy, microscopic visualization was used to identify the protruded disk and the exiting nerve root (Video 1). Given the difficult visualization, a 30-degree endoscopic probe was used, which enabled real-time visualization of the gaseous protrusion being released in the liquid medium. After decompression, microscopic visualization was used for confirmation, with the patient obtaining a good surgical outcome and complete relief of her presenting pain. This case illustrates the synergism between endoscopic and minimally invasive spine surgery techniques and the unique advantages of enabling visualization of spinal anatomy through a liquid medium with the use of an endoscope.1-3.

International Learner Perceptions, Educational Value, and Cost Associated With the Use of Start-to-Finish Surgical Simulation Compared With Cadaveric Models.

BACKGROUND: Graduate surgical education is highly variable across regions and institutions regarding case volume and degree of trainee participation in each case. Dedicated educational curriculum using cadaveric tissue has been shown to enhance graduate surgical training, however with associated financial and utility burden to the institution. OBJECTIVE: To investigate the utility of educational and cost applications of a novel method of combining mixed organic hydrogel polymers and 3-dimensional printed anatomic structures to create a complete "start-to-finish" simulation for resident education in spinal anatomy, instrumentation, and surgical techniques. METHODS: This qualitative pilot study investigated 14 international participants on achievement of objective and personal learning goals in a standardized curriculum using biomimetic simulation compared with cadaveric tissue. A questionnaire was developed to examine trainee evaluation of individual anatomic components of the biomimetic simulators compared with previous experience with cadaveric tissue. RESULTS: A total of 210 responses were acquired from 14 participants. Six participants originated from US residency education programs and 8 from transcontinental residency programs. Survey results for the simulation session revealed high user satisfaction. Score averages for each portion of the simulation session indicated learner validation of anatomic features for the simulation compared with previous cadaveric experience. Cost analysis resulted in an estimated savings of $10 833.00 for this single simulation session compared with previous cadaveric tissue sessions. CONCLUSION: The results of this study indicate a strong potential of establishing biomimetic simulation as a cost-effective and high-quality alternative to cadaveric tissue for the instruction of fundamental spine surgical techniques.

Interactive Neurosurgery Lecture Series: A Global Education Platform of Tele-Teaching During the Coronavirus Disease 2019 Pandemic and Beyond.

OBJECTIVE: To explore the worldwide impact of a virtual neurosurgery-neuroscience lecture series on optimizing neurosurgical education with tele-teaching. METHODS: A retrospective analysis was performed from our Zoom database to collect data from October 15, 2020, to December 14, 2020, and from September 27, 2021, to December 13, 2021. A comparative analysis of participants in the 2 different time frames was performed to investigate the impact of tele-teaching on neurosurgical education worldwide. To evaluate participant satisfaction, the yearly continuing medical education reports of 2020-2021 were analyzed. Data related to the distribution of lectures by subspecialties were also described. RESULTS: Among the 11 lectures of the first period, 257 participants from 17 countries in 4 different continents were recorded, with a mean of 64 (standard deviation = 9.30) participants for each meeting; 342 attendees participated from 19 countries in 5 continents over the 11 lectures of the second part, with an average of 82.8 (standard deviation = 14.04) attendees; a statistically significant increase in participation between the 2 periods was identified (P < 0.001) A total of 19 (2020) and 21 (2021) participants submitted the continuing medical education yearly survey. More than 86.4% of overall responses considered the lectures "excellent." The main topics reported during lectures in 2020-2021 were related to brain tumors (33.7%) and education (22.1%). CONCLUSIONS: The COVID-19 pandemic has increased the need to introduce new educational approaches for teaching novel ways to optimize patient care. Our multidisciplinary Web-based virtual lecture series could represent an innovative tele-teaching platform in neurosurgical training.

SPECT-CT as a Predictor of Pain Generators in Patients Undergoing Intra-Articular Injections for Chronic Neck and Back Pain.

BACKGROUND: The ability to accurately predict pain generators for chronic neck and back pain remains elusive. OBJECTIVE: We evaluated whether injections targeted at foci with uptake on single-photon emission computerized tomography-computed tomography (SPECT-CT) were associated with improved outcomes in patients with chronic neck and back pain. METHODS: A retrospective review was completed on patients undergoing SPECT-CT for chronic neck and back pain between 2016 and 2020 at a tertiary academic center. Patients' records were reviewed for demographic, clinical, imaging, and outcomes data. Only those patients who had facet injections after SPECT-CT were included in this evaluation. Patients undergoing injections targeted at foci of abnormal radiotracer uptake were compared with patients without uptake concerning immediate positive response, visual analog scale, and the need for additional injection or surgery at the target level. RESULTS: A total of 2849 patients were evaluated with a SPECT-CT for chronic neck and back pain. Of those, 340 (11.9%) patients received facet joint injections after SPECT-CT. A propensity score regression analysis adjusted for age, gender, body mass index, hypertension, multiple target injections, and injection location showed uptake targeted injections not being associated with an improved immediate positive response (odds ratio: 0.64; 95% confidence interval: 0.34-1.21; P = 0.172). In patients with a failed facet injection preceding SPECT-CT, adding SPECT-CT to guide facet injections was associated with a decrease in visual analog scale pain scores 2 weeks after injection (P = 0.018), particularly when changes were made to the facets being targeted (P = 0.010). CONCLUSION: This study suggests that there is benefit with SPECT-CT specially to guide facet injections after failed prior facet injections.

Robotic-Assisted vs Nonrobotic-Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Cost-Utility Analysis.

BACKGROUND: Management of degenerative disease of the spine has evolved to favor minimally invasive techniques, including nonrobotic-assisted and robotic-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Value-based spending is being increasingly implemented to control rising costs in the US healthcare system. With an aging population, it is fundamental to understand which procedure(s) may be most cost-effective. OBJECTIVE: To compare robotic and nonrobotic MIS-TLIF through a cost-utility analysis. METHODS: We considered direct medical costs related to surgical intervention and to the hospital stay, as well as 1-yr utilities. We estimated costs by assessing all cases involving adults undergoing robotic surgery at a single institution and an equal number of patients undergoing nonrobotic surgery, matched by demographic and clinical characteristics. We adopted a willingness to pay of $50 000/quality-adjusted life year (QALY). Uncertainty was addressed by deterministic and probabilistic sensitivity analyses. RESULTS: Costs were estimated based on a total of 76 patients, including 38 undergoing robot-assisted and 38 matched patients undergoing nonrobot MIS-TLIF. Using point estimates, robotic surgery was projected to cost $21 546.80 and to be associated with 0.68 QALY, and nonrobotic surgery was projected to cost $22 398.98 and to be associated with 0.67 QALY. Robotic surgery was found to be more cost-effective strategy, with cost-effectiveness being sensitive operating room/materials and room costs. Probabilistic sensitivity analysis identified robotic surgery as cost-effective in 63% of simulations. CONCLUSION: Our results suggest that at a willingness to pay of $50 000/QALY, robotic-assisted MIS-TLIF was cost-effective in 63% of simulations. Cost-effectiveness depends on operating room and room (admission) costs, with potentially different results under distinct neurosurgical practices.

Minimally Invasive Transforaminal Lumbar Interbody Fusion: Cost of a Surgeon's Learning Curve.

BACKGROUND: Minimally invasive transforaminal interbody fusion has become an increasingly common approach in adult degenerative spine disease but is associated with a steep learning curve. We sought to evaluate the impact of the learning experience on mean procedure time and mean cost associated with each procedure. METHODS: We studied the first 100 consecutive minimally invasive transforaminal interbody fusion procedures of a single surgeon. We performed multivariable linear regression models, modeling operating time, and costs in function of the procedure order adjusted for patients' age, sex, and number of surgical levels. The number of procedures necessary to attain proficiency was determined through a k-means cluster analysis. Finally, the total excess operative time and total excess cost until obtaining proficiency was evaluated. RESULTS: Procedure order was found to impact procedure time and mean costs, with each successive case being associated with progressively less procedure time and cost. On average, each successive case was associated with a reduction in procedure time of 0.97 minutes (95% confidence interval 0.54-1.40; P < 0.001) and an average adjusted reduction in overall costs of $82.75 (95% confidence interval $35.93-129.57; P < 0.001). An estimated 58 procedures were needed to attain proficiency, translating into an excess procedure time of 2604.2 minutes (average of 45 minutes per case), overall costs associated with the learning experience of $226,563.8 (average of $3974.80 per case), and excess surgical cost of $125,836.6 (average of $2207.66 per case). CONCLUSIONS: Successive cases were associated with progressively less procedure time and mean overall and surgical costs, until a proficiency threshold was attained.

Initial Results of Precision Treatment of Postoperative Cerebrospinal Fluid Leak with Ultrasound-Guided Epidural Blood Patch.

BACKGROUND: Incidental durotomy, a known complication of spinal surgery, can lead to persistent cerebrospinal fluid leak and pseudomeningocele if unrecognized or incompletely repaired. We describe the use of ultrasound to visualize the site of durotomy, observe the aspiration of the pseudomeningocele, and guide the precise application of an ultrasound-guided epidural blood patch (US-EBP), under direct visualization in real time. METHODS: A retrospective review was performed to determine demographic, procedural, and outcome characteristics for patients who underwent US-EBP for symptomatic postoperative pseudomeningocele. RESULTS: Overall, 48 patients who underwent 49 unique episodes of care were included. The average age and body mass index were 60.5 (±12.6) years and 27.8 (±4.50) kg/m2, respectively. The most frequent index operation was laminectomy (24.5%), and 36.7% of surgeries were revision operations. Durotomy was intended or recognized in 73.4% of cases, and the median time from surgery to symptom development was 7 (interquartile range 4-16) days. A total of 61 US-EBPs were performed, with 51.0% of patients experiencing resolution of their symptoms after the first US-EBP. An additional 20.4% were successful with multiple US-EBP attempts. Complications occurred in 14.3% of cases, and the median clinical follow-up was 4.3 (interquartile range 2.4-14.5) months. CONCLUSIONS: This manuscript represents the largest series in the literature describing US-EBP for the treatment of postoperative pseudomeningocele. The success rate suggests that routine utilization of US-guided EBP may allow for targeted treatment of pseudomeningoceles, without the prolonged hospitalization associated with lumbar drains or the risks of general anesthesia and impaired wound healing associated with surgical revision.

Image-Guided Right T10 Costotransverse Joint Resection for Costotransversitis: Operative Technique and Nuances: 2-Dimensional Operative Video.

We describe the operative approach and management for costotransverse joint inflammation in a 49-yr-old man with worsening midthoracic pain radiating to the right paraspinal area. He underwent physical therapy with no relief of his symptoms. Thoracic spine magnetic resonance imaging (MRI) revealed severe arthritic changes involving the right T10 costotransverse joint. Scoliosis X-rays showed a dextroconvex curvature in the midthoracic spine, without any significant imbalance. Single-photon emission computed tomography (SPECT) scan revealed focal increased uptake of the right T10 costotransverse joint. T10 costotransverse joint lidocaine injection did not provide any relief. We performed a computed tomography (CT)-guided biopsy, which was negative for malignancy and also cultures were negative. MRI revealed a significant enhancement in this area and the patient's C-reactive Protein was elevated. Decision was made to perform open biopsy and costotransverse joint resection. We present a case of minimally invasive, image-guided costotransverse joint resection, which has not been described in the literature. The right T10 costotransverse joint was dissected out with the image-guided dilator, and tubular retractors were inserted. Under the microscope, using the image-guided drill, the right T10 costotransverse joint was drilled out. The lateral aspect of the right T10 process was drilled out as well as the medial-dorsal aspect of the right T10 rib. The patient recovered from surgery well with abatement of his preoperative thoracic pain, which remained abated at 6-mo follow-up. This case highlights the complex technical nuances of this procedure, and the importance of a thorough preoperative evaluation with a bone SPECT scan to help localize the pain generator. Patient consented for the procedures and for the publication of the video.

Perioperative Comparison of Robotic-Assisted Versus Fluoroscopically Guided Minimally Invasive Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: Robotic surgical systems have been developed to improve spine surgery accuracy. Studies have found significant reductions in screw revision rates and radiation exposure with robotic assistance compared with open surgery. The aim of the present study was to compare the perioperative outcomes between robot-assisted (RA) and fluoroscopically guided (FG) minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF) performed by a single surgeon. METHODS: The present retrospective cohort study analyzed all patients with lumbar degenerative disease who had undergone MI-TLIF by a single surgeon from July 2017 to March 2020. One group had undergone FG MI-TLIF and one group had undergone RA MI-TLIF. RESULTS: Of the 101 patients included in the present study, 52 had undergone RA MI-TLIF and 49, FG MI-TLIF. We found no statistically significant differences in the operative time (RA, 241 ± 69.3 minutes; FG, 246.2 ± 56.3 minutes; P = 0.681). The mean radiation time for the RA group was 32.8 ± 28.8 seconds, and the mean fluoroscopy dose was 31.5 ± 30 mGy. The RA radiation exposure data were compared with similar data for the FG MI-TLIF group in a previous study (59.5 ± 60.4 mGy), with our patients' radiation exposure significantly lower (P = 0.035). The postoperative complications and rates of surgical revision were comparable. CONCLUSIONS: Our results have demonstrated that RA MI-TLIF provides perioperative outcomes comparable to those with FG MI-TLIF. A reduced radiation dose to the patient was observed with RA compared with FG MI-TLIF. No differences were noted between the RA and FG cohorts in operative times, complication rates, revision rates, or length of stay.

Investigation of a three-dimensional printed dynamic cervical spine model for anatomy and physiology education.

INTRODUCTION: Three-dimensional (3D) printing of anatomical structures is a growing method of education for students and medical trainees. These models are generally produced as static representations of gross surface anatomy. In order to create a model that provides educators with a tool for demonstration of kinematic and physiologic concepts in addition to surface anatomy, a high-resolution segmentation and 3D-printingtechnique was investigated for the creation of a dynamic educational model. METHODS: An anonymized computed tomography scan of the cervical spine with a diagnosis of ossification of the posterior longitudinal ligament was acquired. Using a high-resolution thresholding technique, the individual facet and intervertebral spaces were separated, and models of the C3-7 vertebrae were 3D-printed. The models were placed on a myelography simulator and subjected to flexion and extension under fluoroscopy, and measurements of the spinal canal diameter were recorded and compared to in-vivo measurements. The flexible 3D-printed model was then compared to a static 3D-printed model to determine the educational benefit of demonstrating physiologic concepts. RESULTS: The canal diameter changes on the flexible 3D-printed model accurately reflected in-vivo measurements during dynamic positioning. The flexible model also was also more successful in teaching the physiologic concepts of spinal canal changes during flexion and extension than the static 3D-printed model to a cohort of learners. CONCLUSIONS: Dynamic 3D-printed models can provide educators with a cost-effective and novel educational tool for not just instruction of surface anatomy, but also physiologic concepts through 3D ex-vivo modeling of case-specific physiologic and pathologic conditions.

Establishing a Cost-Effective 3-Dimensional Printing Laboratory for Anatomical Modeling and Simulation: An Institutional Experience.

SUMMARY STATEMENT: Three-dimensional (3D) printing is rapidly growing in popularity for anatomical modeling and simulation for medical organizations across the world. Although this technology provides a powerful means of creating accurately representative models of anatomic structures, there remains formidable financial and workforce barriers to understanding the fundamentals of technology use, as well as establishing a cost- and time-effective system for standardized incorporation into a workflow for simulator design and anatomical modeling. There are many factors to consider when choosing the appropriate printer and accompanying software to succeed in accomplishing the desired goals of the executing team. The authors have successfully used open-access software and desktop fused deposition modeling 3D printing methods to produce more than 1000 models for anatomical modeling and procedural simulation in a cost-effective manner. It is our aim to share our experience and thought processes of implementing 3D printing into our anatomical modeling and simulation workflow to encourage other institutions to comfortably adopt this technology into their daily routines.

Postoperative Restrictions After Anterior Cervical Discectomy and Fusion.

No scientific evidence on restrictions for patients following an anterior cervical discectomy and fusion (ACDF) is available. The goal of this study is to assess the practice and patterns of restrictions after single-level and multilevel ACDF at an academic institution. We submitted two questionnaires, for restrictions after single-level and multilevel ACDF, to 18 spine surgeons at our institution. Questions included length of time in practice, use of cervical collar, postoperative restrictions and practices. We received 10 complete responses. Four (40%) of the respondents were in practice for less than 5 years; 3 (30%) 5 or more years, but less than 10; 1 (10%) 10 or more years, but less than 20; 2 (20%) 20 or more years. Only two (20%) surgeons recommend a cervical collar after a single-level ACDF, while seven (70%) do so after a multilevel ACDF, for an average of 9.1 weeks and standard deviation (SD) of 2.8. Nine surgeons (90%) reported providing lifting restrictions after a single-level and multilevel ACDF, with a mean of 10 kg and SD of 2.5 in both cases. 5 (50%) give driving restrictions after a single-level ACDF, eight (80%) do so after a multilevel. eight (80%) recommend physical therapy after both single-level and multilevel ACDF. three (30%) obtain a CT to confirm fusion at one year. Only two (20%) recommend a bone stimulator. Significant variability exists among surgeons in regards to restrictions following ACDF, but some areas of consensus emerged: 90% of respondents give lifting restrictions, with a mean of 10 kg, 80% recommend physical therapy for a range of motion and muscle strengthening.

Kyphosis Correction in Patients Undergoing a Four-Level Anterior Cervical Discectomy and Fusion.

Introduction Cervical kyphotic deformity can be quite debilitating. Most patients present with neck pain, but they can also present with radiculopathy, myelopathy, altered vertical gaze, swallowing problems, and even cosmetic issues from the severe kyphotic deformity. After failing conservative management, surgery remains the only option for halting symptom progression. Surgical options for cervical kyphosis have included anterior-only approaches, posterior-only approaches, or 360- and 540-degree reconstructions. This paper addresses the correction of cervical kyphotic deformity via an anterior-only approach consisting of a four-level anterior cervical discectomy and fusion (ACDF). Methods We interrogated our procedure log system and the keyword "anterior cervical discectomy and fusion (ACDF)" was typed into the search bar. All patients with an ACDF for the past five years were reviewed and patients with a four-level ACDF were selected. Chart review was performed and patients presenting with multi-level cervical stenosis with kyphosis were included in the study. Pre- and post-surgery images were reviewed, and the degrees of pre-operative kyphosis and post-operative lordosis were measured. Results  Our search produced 20 patients. All the patients had a diagnosis of multi-level cervical stenosis with or without myelopathy and were all symptomatic. Pre-operative kyphosis ranged from 2.3 to 35 (mean 11.5) degrees, and post-operative lordosis ranged from 2 to 38 (mean 16) degrees. All the patients had varying degrees of kyphosis correction post-surgery which ranged from 6 to 44 (mean 27) degrees. Significant improvement or complete resolution of symptoms post-operatively occurred in all patients. Conclusion  Four-level ACDF in carefully selected patients can be used to correct cervical alignment in patients presenting with symptomatic multi-level cervical stenosis with kyphosis.

Path to Reopening Surgery in the COVID-19 Pandemic: Neurosurgery Experience.

OBJECTIVE: To test the efficacy of an innovative coronavirus disease 2019 (COVID-19) preoperative triage protocol as a way to gradually reopen and ramp-up elective surgeries. PATIENTS AND METHODS: We reviewed clinical, radiographic, and laboratory data for all patients who underwent surgery within the neurosurgery department from March 26 through April 22, 2020. We collected data on demographic information, comorbidities, preoperative COVID-19 test results, whether COVID-19 respiratory or other symptoms were developed during hospitalization, hospital length of stay, discharge disposition, and postoperative COVID-19 test results. RESULTS: Using a combination of both preoperative outpatient COVID-19 drive-through and inpatient testing to obtain surgical clearance with selected telemedicine evaluations, 103 nonelective neurosurgical procedures were performed in 102 patients. No patients tested positive for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) 48 hours before surgery. None of the patients developed any COVID-19 symptoms during their hospitalization or were readmitted to our emergency department postoperatively for COVID-19 symptoms. CONCLUSION: We describe a multifaceted preoperative triage protocol for safely performing nonelective neurosurgical procedures during the COVID-19 pandemic, which could help other neurosurgical departments and hospitals minimize coronavirus exposure for patients and health care workers. We believe this triage strategy could be implemented at other centers to gradually restart a process toward elective surgeries in a safe way.