Minimally invasive multiple-rod constructs with robotics planning in adult spinal deformity surgery: a case series.

PURPOSE: Multiple-rod constructs (MRCs) are often used in deformity correction for increased stability and rigidity. There are currently no reports showing minimally invasive placement of MRCs in adult deformity surgery and its technical feasibility through preoperative software planning. METHODS: Data were collected retrospectively from medical records of six consecutive patients who underwent minimally invasive MRCs with robotics planning by a single surgeon at an academic center between March-August 2020. RESULTS: A total of six patients (4 females, mean age 69.7 years) underwent minimally invasive long-segment (6 +) posterior fixation with multiple rods (3 +) using the Mazor X Stealth Edition robotics platform. Average follow-up was 14.3 months. All patients underwent oblique lumbar interbody fusion (OLIF) as a first stage, followed by second stage posterior fixation in the same day. The mean number of levels posteriorly instrumented was 8.8. One patient underwent 3 rod fixation (1 iliac, 2 S2AI) and 5 patients underwent quad rod fixation (2 iliac, 2 S2AI). The mean time to secure all rods was 8 min 36 s. Mean improvement in spinopelvic parameters was -4.9 cm sagittal vertical axis, 18.0° lumbar lordosis, and -10.7° pelvic tilt with an average pelvic incidence of 62.5°. Estimated blood loss (EBL) was 100-250 cc with no blood transfusions, and all but one patient ambulated on postoperative day 1 or 2. CONCLUSION: Spinal robotics brings us into a new era of minimally invasive construct design. To our knowledge, this is the first description of the technical feasibility of MRCs in minimally invasive adult spinal deformity surgery.

The effect of anterior lumbar interbody fusion staging order on perioperative complications in circumferential lumbar fusions performed within the same hospital admission.

OBJECTIVE: Anterior lumbar interbody fusion (ALIF) is a powerful technique that provides wide access to the disc space and allows for large lordotic grafts. When used with posterior spinal fusion (PSF), the procedures are often staged within the same hospital admission. There are limited data on the perioperative risk profile of ALIF-first versus PSF-first circumferential fusions performed within the same hospital admission. In an effort to understand whether these procedures are associated with different perioperative complication profiles, the authors performed a retrospective review of their institutional experience in adult patients who had undergone circumferential lumbar fusions. METHODS: The electronic medicals records of patients who had undergone ALIF and PSF on separate days within the same hospital admission at a single academic center were retrospectively analyzed. Patients carrying a diagnosis of tumor, infection, or traumatic fracture were excluded. Demographics, surgical characteristics, and perioperative complications were collected and assessed. RESULTS: A total of 373 patients, 217 of them women (58.2%), met the inclusion criteria. The mean age of the study cohort was 60 years. Surgical indications were as follows: degenerative disease or spondylolisthesis, 171 (45.8%); adult deformity, 168 (45.0%); and pseudarthrosis, 34 (9.1%). The majority of patients underwent ALIF first (321 [86.1%]) with a mean time of 2.5 days between stages. The mean number of levels fused was 2.1 for ALIF and 6.8 for PSF. In a comparison of ALIF-first to PSF-first cases, there were no major differences in demographics or surgical characteristics. Rates of intraoperative complications including venous injury were not significantly different between the two groups. The rates of postoperative ileus (11.8% vs 5.8%, p = 0.194) and ALIF-related wound complications (9.0% vs 3.8%, p = 0.283) were slightly higher in the ALIF-first group, although the differences did not reach statistical significance. Rates of other perioperative complications were no different. CONCLUSIONS: In patients undergoing staged circumferential fusion with ALIF and PSF, there was no statistically significant difference in the rate of perioperative complications when comparing ALIF-first to PSF-first surgeries.

Cervical disc arthroplasty: tips and tricks.

Cervical disc arthroplasty (CDA) is a powerful, motion-sparing treatment option for managing cervical radiculopathy or myelopathy. While CDA can be an excellent surgery for properly indicated patients, it is also less forgiving than cervical fusion. Optimally resolving patient symptoms while maintaining range of motion relies on near perfection in the surgical technique. Different CDA options exist on the market, with some having long-term proven success and others in early stages of clinical trials. We discuss the different options available for use, as well as strategies of positioning, approach, disc space preparation, implantation, and fusion prevention that we believe can help improve performance and outcomes of CDA.

Cost-effectiveness development for the postoperative care of craniotomy patients: a safe transitions pathway in neurological surgery.

OBJECTIVE The authors' institution is in the top 5th percentile for hospital cost in the nation, and the neurointensive care unit (NICU) is one of the costliest units. The NICU is more expensive than other units because of lower staff/patient ratio and because of the equipment necessary to monitor patient care. The cost differential between the NICU and Neuro transitional care unit (NTCU) is $1504 per day. The goal of this study was to evaluate and to pilot a program to improve efficiency and lower cost by modifying the postoperative care of patients who have undergone a craniotomy, sending them to the NTCU as opposed to the NICU. Implementation of the pilot will expand and utilize neurosurgery beds available on the NTCU and reduce the burden on NICU beds for critically ill patient admissions. METHODS Ten patients who underwent craniotomy to treat supratentorial brain tumors were included. Prior to implementation of the pilot, inclusion criteria were designed for patient selection. Patients included were less than 65 years of age, had no comorbid conditions requiring postoperative intensive care unit (ICU) care, had a supratentorial meningioma less than 3 cm in size, had no intraoperative events, had routine extubation, and underwent surgery lasting fewer than 5 hours and had blood loss less than 500 ml. The Safe Transitions Pathway (STP) was started in August 2016. RESULTS Ten tumor patients have utilized the STP (5 convexity meningiomas, 2 metastatic tumors, 3 gliomas). Patients' ages ranged from 29 to 75 years (median 49 years; an exception to the age limit of 65 years was made for one 75-year-old patient). Discharge from the hospital averaged 2.2 days postoperative, with 1 discharged on postoperative day (POD) 1, 7 discharged on POD 2, 1 discharged on POD 3, and 1 discharged on POD 4. Preliminary data indicate that quality and safety for patients following the STP (moving from the operating room [OR] to the neuro transitional care unit [OR-NTCU]) are no different from those of patients following the traditional OR-NICU pathway. No patients required escalation in level of nursing care, and there were no readmissions. This group has been followed for greater than 1 month, and there were no morbidities. CONCLUSIONS The STP is a new and efficient pathway for the postoperative care of neurosurgery patients. The STP has reduced hospital cost by $22,560 for the first 10 patients, and there were no morbidities. Since this pilot, the authors have expanded the pathway to include other surgical cases and now routinely schedule craniotomy patients for the (OR-NTCU) pathway. The potential cost reduction in one year could reach $500,000 if we reach our potential of 20 patients per month.

Familial gliomas: cases in two pairs of brothers.

The majority of gliomas are sporadic in origin. Familial gliomas have been reported, though they are exceptionally rare. Several familial cancer syndromes are associated with autosomal dominant glioma risk, typically with incomplete penetrance. When two siblings are affected in the absence of a known dominantly inherited cancer syndrome, an autosomal recessive condition may be suspected (e.g. constitutional mismatch repair syndrome). We present two separate sets of siblings, one set with low grade gliomas, and the other with high grade gliomas. Histology for all tumors were either oligodendroglioma or had features of oligodendroglioma. Interestingly, there is a nearly identical histopathology and anatomical localization noted in these clinical presentations. For one family, genetic testing and family inquiry have resulted in no identifiable genetic pattern of disease. High-penetrance familial mutations and common low-penetrance susceptibility loci (e.g. single-nucleotide polymorphism (SNPs)) may contribute to familial glioma risk. We present two instances of familial glioma without an identifiable genetic cause. These cases implicate a potential heritable etiology for glioma families in which Mendelian disorders have not been identified. Further investigation should focus on identifying the potential genetic links involved with cases such as the ones presented here.

Ultrasound-guided percutaneous injection of methylene blue to identify nerve pathology and guide surgery.

OBJECT The objective of this study was to provide a technique that could be used in the preoperative period to facilitate the surgical exploration of peripheral nerve pathology. METHODS The authors describe a technique in which 1) ultrasonography is used in the immediate preoperative period to identify target peripheral nerves, 2) an ultrasound-guided needle electrode is used to stimulate peripheral nerves to confirm their position, and then 3) a methylene blue (MB) injection is performed to mark the peripheral nerve pathology to facilitate surgical exploration. RESULTS A cohort of 13 patients with varying indications for peripheral nerve surgery is presented in which ultrasound guidance, stimulation, and MB were used to localize and create a road map for surgeries. CONCLUSIONS Preoperative ultrasound-guided MB administration is a promising technique that peripheral nerve surgeons could use to plan and execute surgery.

Mismatch Between Pelvic Incidence and Lumbar Lordosis After Personalized Interbody Fusion: The Importance of Preoperative Planning and Alignment in Degenerative Spine Diseases.

BACKGROUND: Emerging data have highlighted the significance of planning and aligning total and segmental lumbar lordosis with pelvic morphology when performing short-segment fusion with the goal of reducing the risk of adjacent segment disease while also decreasing spine-related disability. This study evaluates the impact of personalized interbody implants in restoring pelvic incidence-lumbar lordosis (PI-LL) mismatch compared with a similar study using stock interbody implants. METHODS: This multicenter retrospective analysis assessed radiographic pre- and postoperative spinopelvic alignment (PI-LL) in patients who underwent 1- or 2-level lumbar fusions with personalized interbody implants for degenerative (nondeformity) indications. The aim was to assess the incidence of malalignment (PI-LL ≥ 10°) both before and after fusion surgery and to determine the rate of alignment preservation and/or correction in this population. RESULTS: There were 135 patients included in this study. Of 83 patients who were aligned preoperatively, alignment was preserved in 76 (91.6%) and worsened in 7 (8.4%). Among the 52 preoperatively malaligned patients, alignment was restored in 23 (44.2%), and 29 (55.8%) were not fully corrected. Among patients who were preoperatively aligned, there was no statistically significant difference in either the "preserved" or "worsened" groups between stock devices and personalized interbody devices. In contrast, among patients who were preoperatively malaligned, there was a statistically significant increase in the "restored" group (P = 0.046) and a statistically significant decrease in the "worsened" groups in patients with personalized interbodies compared with historical stock device data (P < 0.05). CONCLUSIONS: Compared with a historical cohort with stock implants, personalized interbody implants in short-segment fusions have shown a statistically significant improvement in restoring patients to normative PI-LL. Using 3-dimensional preoperative planning combined with personalized implants provides an important tool for planning and achieving improvement in spinopelvic parameters.

Patient-specific rods in adult spinal deformity: a systematic review.

PURPOSE: The purpose of this review was to evaluate the effectiveness of patient-specific rods for adult spinal deformity. METHODS: A systematic review of the literature was performed through an electronic search of the PubMed, Scopus, and Web of Science databases. Human studies between 2012 and 2023 were included. Sample size, sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis (PI-LL), pelvic tilt (PT), operation time, blood loss, follow-up duration, and complications were recorded for each study when available. RESULTS: Seven studies with a total of 304 adult spinal deformity patients of various etiologies were included. All studies reported SVA, and PT; two studies did not report PI-LL. Four studies reported planned radiographic outcomes. Two found a significant association between preoperative plan and postoperative outcome in all three outcomes. One found a significant association for PI-LL alone. The fourth found no significant associations. SVA improved in six of seven studies, PI-LL improved in all five, and three of seven studies found improved postoperative PT. Significance of these results varied greatly by study. CONCLUSION: Preliminary evidence suggests potential benefits of PSRs in achieving optimal spino-pelvic parameters in ASD surgery. Nevertheless, conclusions regarding the superiority of PSRs over traditional rods must be judiciously drawn, given the heterogeneity of patients and study methodologies, potential confounding variables, and the absence of robust randomized controlled trials. Future investigations should concentrate on enhancing preoperative planning, standardizing surgical methodologies, isolating specific patient subgroups, and head-to-head comparisons with traditional rods to fully elucidate the impact of PSRs in ASD surgery.

Radiographic Alignment in Deformity Patients Treated With Personalized Interbody Devices: Early Experience From the COMPASS Registry.

BACKGROUND: Literature supports the need for improved techniques to achieve spinopelvic alignment and reduce complication rates in patients with adult spinal deformity (ASD). Personalized interbody devices were developed to address this need and are under evaluation in the multicenter Clinical Outcome Measures in Personalized aprevo (circle R superscript) Spine Surgery (COMPASS (TM suprascript) registry. This report presents interim COMPASS pre- and postoperative sagittal alignment results and complication rates for a subcohort of COMPASS patients diagnosed and surgically treated for spinal deformity. METHODS: COMPASS is a postmarket observational registry of patients enrolled either before or after index surgery and then followed prospectively for 24 months. Sagittal alignment was assessed with SRS-Schwab modifiers for pelvic incidence minus lumbar lordosis, pelvic tilt, and T1 pelvic angle. Summed SRS-Schwab modifiers were utilized to assign overall deformity status as mild, moderate, or severe. Complications were extracted from patient medical records. RESULTS: The study included 67 patients from 9 centers. Preoperative severe deformity was observed in 66% of patients. Index surgeries included implantation of a median of 2 personalized interbody devices by anterior, lateral, or transforaminal approaches and with a median of 8 posteriorly instrumented levels. Overall postoperative sagittal alignment improved with a significant decrease in the mean sum of SRS-Schwab modifiers that correlated strongly to improvements in pelvic incidence minus lumbar lordosis. Among 44 patients with preoperative severe overall deformity, 16 improved to moderate and 9 to mild deformity. Complications occurred for 13 patients (19.4%), including 1 mechanical complication requiring revision 9 months after surgery and none related to personalized interbody devices. CONCLUSIONS: This study demonstrates that ASD patients whose treatment included personalized interbody devices can obtain favorable postoperative alignment status comparable to published results and with no complications related to the personalized interbody devices. CLINICAL RELEVANCE: This study contributes to growing evidence that personalized interbody devices contribute to improved sagittal alignment in ASD patients by directly adjusting the orientation of adjacent vertebra.

Predictability in Achieving Target Intervertebral Lordosis Using Personalized Interbody Implants.

BACKGROUND: Lumbar lordosis distribution has become a pivotal factor in re-establishing the foundational alignment of the lumbar spine. This can directly influence overall sagittal alignment, leading to improved long-term outcomes for patients. Despite the wide availability of hyperlordotic stock cages intended to achieve optimal postoperative alignment, there is a lack of correlation between the lordotic shape of a cage and the resultant intervertebral alignment. Recently, personalized spine surgery has witnessed significant advancements, including 3D-printed personalized interbody implants, which are customized to the surgeon's treatment and alignment goals. This study evaluates the reliability of 3D-printed patient-specific interbody implants to achieve the planned postoperative intervertebral alignment. METHODS: This is a retrospective study of 217 patients with spinal deformity or degenerative conditions. Patients were included if they received 3D-printed personalized interbody implants. The desired intervertebral lordosis (IVL) angle was prescribed into the device design for each personalized interbody (IVL goal). Standing postoperative radiographs were measured, and the IVL offset was calculated as IVL achieved minus IVL goal. RESULTS: In this patient population, 365 personalized interbodies were implanted, including 145 anterior lumbar interbody fusions (ALIFs), 99 lateral lumbar interbody fusions (LLIFs), and 121 transforaminal lumbar interbody fusions. Among the 365 treated levels, IVL offset was 1.1° ± 4.4° (mean ± SD). IVL was achieved within 5° of the plan in 299 levels (81.9%). IVL offset depended on the approach of the lumbar interbody fusion and was achieved within 5° for 85.9% of LLIF, 82.6% of transforaminal lumbar interbody fusions and 78.6% of ALIFs. Ten levels (2.7%) missed the planned IVL by >10°. ALIF and LLIF levels in which the plan was missed by more than 5° tended to be overcorrected. CONCLUSIONS: This study supports the use of 3D-printed personalized interbody implants to achieve planned sagittal intervertebral alignment. CLINICAL RELEVANCE: Personalized interbody implants can consistently achieve IVL goals and potentially impact foundational lumbar alignment.

Changes in Alignment at Untreated Vertebral Levels Following Short-Segment Fusion Using Personalized Interbody Cages: Leveraging Personalized Medicine to Reduce the Risk of Reoperation.

BACKGROUND: An abnormal postoperative lordosis distribution index (LDI), which quantifies the ratio between the lordosis at L4 to S1 and the lordosis at L1 to S1, contributes to the development of adjacent segment disease and increased revision rates in patients undergoing short-segment lumbar intervertebral fusions. Incorporating preoperative spinopelvic parameters and LDI into the surgical plan for short-segment fusion is important for guiding alignment restoration and preserving normal preoperative alignment in unfused segments. This study examined changes in LDI, segmental lordosis, and lordosis of the unfused levels in patients treated with personalized interbody cage (PIC) implants. METHODS: This retrospective study evaluated radiographic measurements from 111 consecutively treated patients diagnosed with degenerative spinal conditions and treated with a short-segment fusion of L4 to L5, L5 to S1, or L4 to S1 using PIC implant(s) within 6 months of the fusion procedure. Comparisons of intervertebral lordosis for treated and untreated levels as well as LDI pre- and postoperatively were performed. RESULTS: In patients with a preoperative hypolordotic distribution (LDI < 50%), statistically significant increases were found in LDI postoperatively, approaching the normal LDI range (LDI 50%-80%). Likewise, patients with hyperlordotic distribution preoperatively (LDI > 80%) experienced a decrease in LDI postoperatively, trending toward the normal range, although the changes were not statistically significant. Intervertebral lordosis for the L5 to S1 level increased significantly following the placement of a PIC in the normal and hypolordotic LDI groups. Changes in intervertebral lordosis for L5 to S1 were not significant for patients with preoperative hyperlordotic LDI. Reciprocal changes in intervertebral lordosis at L1 to L4 were not observed in any groups. CONCLUSIONS: PIC implants may provide a benefit for patients, particularly those with hypolordotic distributions preoperatively. They have the potential to further improve patient outcomes by helping surgeons to achieve patient-specific lordosis goals, which may help to reduce the risk of adjacent segment disease and revisions in patients undergoing short-segment lumbar intervertebral fusions. CLINICAL RELEVANCE: Personalized implants can help surgeons achieve patient-specific alignment goals, potentially prevent adjacent segment disease, and reduce long-term reinterventions.

Assessing the Fractional Curve for Proper Management of Adult Degenerative Scoliosis.

Adult degenerative scoliosis (ADS) is a coronal plane deformity often accompanied by sagittal plane malalignment. Surgical correction may involve the major and/or distally-located fractional curves (FCs). Correction of the FC has been increasingly recognized as key to ameliorating radicular pain localized to the FC levels. The present study aims to summarize the literature on the rationale for FC correction in ADS. Three databases were systematically reviewed to identify all primary studies reporting the rationale for correcting the FC in ADS. Articles were included if they were English full-text studies with primary data from ADS ( ≥ 18 years old) patients. Seventy-four articles were identified, of which 12 were included after full-text review. Findings suggest FC correction with long-segment fusion terminating at L5 increases the risk of distal junctional degeneration as compared to constructs instrumenting the sacrum. Additionally, circumferential fusion offers greater FC correction, lower reoperation risk, and shorter construct length. Minimally invasive surgery (MIS) techniques may offer effective radiographic correction and improve leg pain associated with foraminal stenosis on the FC concavity, though experiences are limited. Open surgery may be necessary to achieve adequate correction of severe, highly rigid deformities. Current data support major curve correction in ASD where the FC concavity and truncal shift are concordant, suggesting that the FC contributes to the patient's overall deformity. Circumferential fusion and the use of kickstand rods can improve correction and enhance the stability and durability of long constructs. Last, MIS techniques show promise for milder deformities but require further investigation.

Integrating navigation assistance for redirecting freehanded spinal instrumentation: experience and technique.

Retrospective review of all spinal fusions > 3 levels involving the thoracolumbar and/or sacroiliac at a single institution, by a single surgeon between 3/12/2020 and 8/13/2021 were reviewed. All screws that were secondarily navigated after identified as misdirected on intraoperative CT scan were included. Neuromonitoring reports were culled for mA threshold to triggered EMG response for all redirected screws. Intraoperative, post-de novo screw placement images (fluoroscopy scout and intraoperative CT) and post-redirection intraoperative scoliosis films and post-operative scoliosis films were independently reviewed by a senior neuroradiologist. Fifty redirected screws in the thoracic, lumbar, sacral, and ilium were identified as misdirected and redirected via navigation. The new trajectory of all screws was confirmed satisfactory by independent review between a senior neuroradiologist and neurosurgeon. Four screws could not be verified by post-operative imaging (4/50, 8%). All triggered EMG stimulated > 15 mA. No screws required return to the operating room for revision. No patients experienced a post-operative deficit. Redirection of misdirected thoracolumbar and sacroiliac screws can be performed using intraoperative CT and navigation as a means to detect and directly visualize appropriate placement.

Analysis of Personalized Interbody Implants in the Surgical Treatment of Adult Spinal Deformity.

STUDY DESIGN: Multicenter cohort. OBJECTIVES: A report from the International Spine Study Group (ISSG) noted that surgeons failed to achieve alignment goals in nearly two-thirds of 266 complex adult deformity surgery (CADS) cases. We assess whether personalized interbody spacers are associated with improved rates of achieving goal alignment following adult spinal deformity (ASD) surgery. METHODS: ASD patients were included if their surgery utilized 3D-printed personalized interbody spacer(s) and they met ISSG CADS inclusion criteria. Planned alignment was personalized by the surgeon during interbody planning. Planned vs achieved alignment was assessed and compared with the ISSG CADS series that used stock interbodies. RESULTS: For 65 patients with personalized interbodies, 62% were women, mean age was 70.3 years (SD = 8.3), mean instrumented levels was 9.9 (SD = 4.1), and the mean number of personalized interbodies per patient was 2.2 (SD = .8). Segmental alignment was achieved close to plan for levels with personalized interbodies, with mean difference between goal and achieved as follows: intervertebral lordosis = .9° (SD = 5.2°), intervertebral coronal angle = .1° (SD = 4.7°), and posterior disc height = -0.1 mm (SD = 2.3 mm). Achieved pelvic incidence-to-lumbar lordosis mismatch (PI-LL) correlated significantly with goal PI-LL (r = .668, P < .001). Compared with the ISSG CADS cohort, utilization of personalized interbodies resulted in significant improvement in achieving PI-LL <5° of plan (P = .046) and showed a significant reduction in cases with PI-LL >15° of plan (P = .012). CONCLUSIONS: This study supports use of personalized interbodies as a means of better achieving goal segmental sagittal and coronal alignment and significantly improving achievement of goal PI-LL compared with stock devices.

A New Objective Radiographic Criteria for Diagnosis of Adult Idiopathic Scoliosis: Apical Pedicle Diameter Asymmetry.

OBJECTIVE: We sought to test the hypothesis that a difference of ≥1 mm in pedicle diameter between the convex and concave pedicles at the apex of a lumbar curve is a sensitive and/or specific criteria for adult idiopathic scoliosis (AdIS). METHODS: Thirty-nine operative patients with adult deformity and lumbar major curves were identified. A chart review was performed. Radiographic measurements included lumbar Cobb, curve apex, and Cobb levels involved. Apical pedicle diameter at the concavity and convexity of the curve apex were measured. RESULTS: Among these 39 patients, the average Cobb angle was 48.3 degrees. Curve apex averaged at L1/2 (range L1-L3). The curves spanned 4.7 levels (range 3-7). Twenty-five curves had the apex to the left, while 14 had the apex to the right. The average pedicle diameter at the apex was 6.1 mm. Fourteen patients had apical pedicle diameter asymmetry (APDA) >1 mm. Most (7 of 8, or 87.5%) of the patients with a history of adult idiopathic scoliosis had APDA >1 mm. A minority (7 of 31, 22.5%) of patients without known history of adult idiopathic scoliosis had APDA >1 mm (P < 0.01). CONCLUSIONS: Apical pedicle diameter asymmetry is among the sensitive diagnostic criteria for AdIS and may be useful for differentiating lumbar major AdIS from degenerative lumbar scoliosis. The sensitivity of APDA >1 mm is 87.5%, with specificity of 77.4%. We propose a new, sensitive radiographic criterion for adult idiopathic scoliosis. A difference of ≥1 mm in pedicle diameter between the convex and concave pedicles at that apex of a lumbar curve has a sensitivity of 87.5% and specificity of 77.4% for patient-reported history of adolescent scoliosis. It can be a useful tool as exclusion criteria for studies on AdIS.

External Validation of the Global Alignment and Proportion Score as Prognostic Tool for Corrective Surgery in Adult Spinal Deformity: A Systematic Review and Meta-Analysis.

BACKGROUND: Since its proposal, the Global Alignment and Proportion (GAP) score has been the topic of several external validation studies, which have yielded conflicting results. Given the lack of consensus regarding this prognostic tool, the authors aim to assess the accuracy of GAP scores for predicting mechanical complications following adult spinal deformity correction surgery. METHODS: A systematic search was performed using PubMed, Embase, and Cochrane Library for the purpose of identifying all studies evaluating the GAP score as a predictive tool for mechanical complications. GAP scores were pooled using a random-effects model to compare patients reporting mechanical complications after surgery versus those reporting no complications. Where receiver operator curves were provided, the area under the curve (AUC) was pooled. RESULTS: A total of 15 studies featuring 2092 patients were selected for inclusion. Qualitative analysis using Newcastle-Ottawa criteria revealed moderate quality among all included studies (5.99/9). With respect to sex, the cohort was predominantly female (82%). The pooled mean age among all patients in the cohort was 58.55 years, with a mean follow-up of 33.86 months after surgery. Upon pooled analysis, we found that mechanical complications were associated with higher mean GAP scores, albeit minimal (mean difference = 0.571 [ 95% confidence interval: 0.163-0.979]; P = 0.006, n = 864). Additionally, age (P = 0.136, n = 202), fusion levels (P = 0.207, n = 358), and body mass index (P = 0.616, n = 350) were unassociated with mechanical complications. Pooled AUC revealed poor discrimination overall (AUC = 0.69; n = 1206). CONCLUSIONS: GAP scores may have a minimal-to-moderate predictive capability for mechanical complications associated with adult spinal deformity correction.

Safety and Efficacy of High-Dose Tranexamic Acid in Spine Surgery: A Retrospective Single-Institution Series.

OBJECTIVE: Currently, tranexamic acid (TXA) is the most widely used antifibrinolytic agent in spine surgery and has been proven to reduce perioperative blood loss. However, the safety of high-dose regimens remains in established. METHODS: A retrospective chart review was performed to identify all adult patients who underwent spine surgery with high-dose TXA (50 mg/kg loading dose, mg/kg/h maintenance dose) between September 2019 and March 2020. RESULTS: Thirty-six patients were treated with intraoperative high-dose TXA during the study period. The mean age was 56.6 (range: 22-82). Average body mass index was 27.2 (5.1) kg/m2. Average preoperative Charlson Comorbidity Index was 3.0 (2.7). The mean number of spinal levels operated on was 6.9 (4.3). Seven cases (19.4%) were revision surgeries. The mean intraoperative blood loss was 587.1 (900.0) mL, and total blood loss was 623.8 (991.9) mL. Postoperatively, time to ambulation was on average 1.7 (1.7) days. The mean total length of stay was 9.8 days (7.9, range 2-41). The most common indication for surgery was tumor (n = 9, 25%), followed by fracture (n = 8, 22.2%), deformity (n = 7, 19.4%), pseudarthrosis (n = 6, 16.7%), and symptomatic lumbar disc herniation (n = 2, 5.6%). There were no thromboembolic or other significant complications among the 36 patients. CONCLUSIONS: This retrospective case series demonstrates that the use of high-dose TXA provides is potentially safe and efficacious in adult patients undergoing complex spine surgeries. However, further investigations are required before the true safety and optimal dosing can be determined for high-dose TXA.

360 TOTUM ALIF for a Symptomatic Fractional Curve.

As patient-specific implants become a tool in the spine surgeon's arsenal, understanding how to effectively implement multiple systems in a single surgery requires careful planning. In Video 1, we describe our workflow for a total custom anterior lumbar interbody fusion, featuring patient-specific interbodies and rods. We discuss the required cross talk necessary to ensure maximum desired correction, as well as the logic for pursuing custom devices in this index case. Appropriate consent from the patient was obtained before the procedure.

Freehand Juxtapedicular Screws Placed in the Apical Concavity of Adult Idiopathic Scoliosis Patients: Technique, Computed Tomography Confirmation, and Radiographic Results.

OBJECTIVE: The purpose of this study is to highlight our technique for freehand placement of juxtapedicular screws along with intraoperative computed tomography (CT) and radiographic results. METHODS: Consecutive patients with adult idiopathic scoliosis undergoing primary surgery by the senior author were identified. All type D (absent/slit like channel) pedicles were identified on preoperative CT. Three-dimensional visualization software was used to measure screw angulation and purchase. Radiographs were measured by a fellowship trained spine surgeon. The freehand technique was used to place all screws in a juxtapedicular fashion without any fluoroscopic, radiographic, navigational or robotic assistance. RESULTS: Seventy-three juxtapedicular screws were analyzed. The most common level was T7 (9 screws) on the left and T5 (12 screws) on the right. The average medial angulation was 20.7° (range, 7.1°-36.3°), lateral vertebral body purchase was 13.4 mm (range, 0-28.9 mm), and medial vertebral body purchase was 21.1 mm (range, 8.9-31.8 mm). More than half (53.4%) of the screws had bicortical purchase. Two screws were lateral on CT scan, defined by the screw axis lateral to the lateral vertebral body cortex. No screws were medial. There was a difference in medial angulation between screws with (n = 58) and without (n = 15) lateral body purchase (22.0 ± 4.9 vs. 15.5 ± 4.5, p < 0.001). Three of 73 screws were repositioned after intraoperative CT. There were no neurovascular complications. The mean coronal cobb corrections for main thoracic and lumbar curves were 83.0% and 80.5%, respectively, at an average of 17.5 months postoperative. CONCLUSION: Freehand juxtapedicular screw placement is a safe technique for type D pedicles in adult idiopathic scoliosis patients.

Minimally Invasive L5-S1 Oblique Lumbar Interbody Fusion With Simultaneous Robotic Single Position Posterior Fixation: 2-Dimensional Operative Video.

The unique anatomy at L5-S1 presents different challenges and considerations to be made when compared to other areas in the lumbar spine. In this way, the oblique lumbar interbody fusion (OLIF) is more closely related to a supine anterior lumbar interbody fusion (ALIF) except that the former is performed in a lateral position down a smaller minimally invasive retroperitoneal corridor. This lateral positioning at L5-S1, however, provides an opportunity for single-position surgery simultaneously with posterior fixation, which is not afforded by other approaches. We present here a case of a 57-yr-old male with a prior right-sided L5-S1 microdiscectomy who presents with worsening lumbar radiculopathy and foot drop. He subsequently underwent a minimally invasive L5-S1 OLIF with posterior instrumentation placed bilaterally while remaining in a single lateral position (Mazor X Stealth Edition, Medtronic, Dublin, Ireland). Both the anterior OLIF surgeon and posterior instrumentation surgeon were able to work simultaneously. There is currently a need for further high-quality operative videos showing the L5-S1 OLIF technique, and to our knowledge, this is the first video demonstrating a 2-surgeon near-simultaneous workflow approach using a spinal robotics platform at this level. There is no identifying information in this video. A patient consent was obtained for the surgical procedure and for publishing of the material included in the video.