Number Of Instrumented Levels Research Articles

Distal Junctional Failure: A Feared Complication of Multilevel Posterior Spinal Fusions.

Objectives: Distal junctional failure (DJF) is less commonly described than proximal junctional failure following posterior spinal fusion, and particularly adult spinal deformity (ASD) surgery. We describe a case series of patients with DJF, taking into account sagittal spinopelvic alignment, and suggest potential risk factors in light of the current literature. Methods: We performed a single-center, retrospective review of posterior spinal fusion patients with DJF who underwent subsequent revision surgery between June 2009 and January 2019. Demographics and surgical details were collected. Radiographical measurements included the following: preoperative and postoperative sagittal and coronal alignment for each index or revision surgery. The upper-instrumented vertebra (UIV), lower instrumented vertebra (LIV), and fusion length were recorded. Results: Nineteen cases (64.7 ± 13.5 years, 12 women, seven men) were included. The mean follow-up was 4.7 ± 2.4 years. The number of instrumented levels was 6.79 ± 2.97. Among the patients, 84.2% (n = 16) presented at least one known DJF risk factor. LIV was frequently L5 (n = 10) or S1 (n = 2). Six patients had an initial circumferential fusion at the distal end. Initial DJFs were vertebral fracture distal to the fusion (n = 5), screw pull-out (n = 9), spinal stenosis (n = 4), instability (n = 4), and one early DJK. The distal mechanical complications after a first revision included screw pull-out (n = 4), screw fracture (n = 3), non-union (n = 2), and an iatrogenic spondylolisthesis. Conclusions: In this case series, insufficient sagittal balance restoration, female gender, osteoporosis, L5 or S1 LIV in long constructs were associated with DJF. Restoring spinal balance and circumferentially fusing the base of constructs represent key steps to maintain correction and prevent revisions.

Effectiveness of a Preoperative Bowel Preparation Protocol for Patients With Adolescent Idiopathic Scoliosis to Decrease Postoperative Gastrointestinal Morbidities and the Hospital Length of Stay.

Randomised controlled trial. This study aimed to determine the effectiveness of a preoperative bowel preparation protocol comprising bisacodyl to minimize postoperative gastrointestinal morbidities and the hospital length of stay for patients with adolescent idiopathic scoliosis. Patients who undergo scoliosis correction surgery frequently experience postoperative gastrointestinal morbidities and a prolonged hospital length of stay. Emesis, paralytic ileus and constipation are the most common gastrointestinal morbidities. Opioid medication is a well-known risk factor for gastrointestinal complications after scoliosis correction surgery. Eighty-seven patients (22 boys [25.3%] and 65 girls [74.7%]) with a mean age of 17.7years (standard deviation [SD], ±2.2 years) diagnosed with adolescent idiopathic scoliosis were enrolled in this study and randomized into 2 groups. Group A comprised 44 patients who received a preoperative bowel preparation comprising bisacodyl. Group B comprised 43 patients who did not receive any preoperative medication. Demographic data, height, weight, medical and surgical comorbidities, Risser status, number of instrumented levels and preoperative opioid consumption of all patients were evaluated. Group A experienced fewer postoperative abdominal symptoms than group B. The mean hospital length of stay was 4.1 days (SD, ±.6 days; median, 4days; range, 3-5days) for group A; however, it was 5.3days (SD, ±.8 days; median, 5days; range, 4-7days) for group B (P = .01). The use of a bowel preparation protocol before scoliosis correction surgery for patients with adolescent idiopathic scoliosis can effectively decrease postoperative gastrointestinal morbidities and the hospital length of stay.

Outcomes of Dorsolumbar and Lumbar Spinal Tuberculosis Treated by MinimallyInvasive and Open Techniques: A Prospective Comparative Study.

To compare the outcomes of minimally invasive and open techniques in the surgical management of dorsolumbar and lumbar spinal tuberculosis (STB). Skeletally mature patients with active STB involving thoracolumbar and lumbar region confirmed by radiology (X-ray, MRI) and histopathological examination were included. Healed and mechanically stable STB, patients having severe hepatic and renal impairment, coexisting spinal conditions such as ankylosing spondylitis and rheumatoid arthritis, and patients unwilling to participate were excluded from the study. The patients were divided in to two groups, group A consisted of patients treated by MIS techniques and group B consisted of patients treated by open techniques. All the patients had a minimum follow-up of 24months. A total of 42 patients were included in the study. MIS techniques were used in 18 patients and open techniques were used in 24 patients. On comparison between the two groups, blood loss (234ml vs 742ml), and immediate post-operative VAS score (5.26 vs 7.08) were significantly better in group A, whereas kyphotic correction (16° vs 33.25°) was significantly better in group B. Rest of the parameters such as duration of surgery, VAS score, ODI score and number of instrumented levels did not show significant difference between the two groups. MIS stabilization when compared to open techniques is associated with significant improvement in immediate post-operative VAS scores. The MIS approaches at 2-year follow-up have functional results similar to open techniques. MIS is inferior to open techniques in kyphosis correction and may be associated with complications.

Correlation Between Rod Fracture and Shear Stress: A Novel Parameter

We sought to assess the accuracy of a novel parameter proportional to the rod shear stress (RSS) in identifying patients at risk of rod fracture (RF) after surgery for correction of adult spinal deformity. We performed a retrospective medical record review of patients aged ≥18 years treated for adult spinal deformity between 2004 and 2014 with ≥24 months of follow-up. The primary outcome was RFs identified radiographically. Patient weight (w), number of instrumented levels (N), and minimum rod diameter (d) were recorded and used to calculate the RSS parameter (RSS=Nwd2). Receiver operating characteristic curves were produced and the area under the curve (AUC ± 95% confidence interval [CI]) was calculated to compare this parameter's discriminative accuracy to that of its constituent variables. The sensitivity, specificity, and likelihood ratios (LRs) were calculated. A total of 28 RF-positive and 154 RF-negative patients were included. The average age was 59.2 ± 9.6 years, and 93.4% were women. The RSS parameter produced the greatest AUC (0.73 ± 0.11). At an RSS cutoff of 30.1, it achieved a sensitivity of 71.4% and specificity of 71.4% (LR, 2.5; 95% CI, 1.8-3.5). The number of instrumented levels produced the next-greatest AUC (0.65 ± 0.12), with a sensitivity of 78.6% and specificity of 50.0% at a cutoff of 15 (LR, 1.6; 95% CI, 1.2-2.0). The RSS is calculated using easily obtainable information and shows potential as a tool for predicting patient-specific risk of RF after spinal fusion. The number of instrumented levels also correlates strongly with the occurrence of RFs and is not significantly less accurate than the RSS. A larger sample size and prospective validation would be useful in determining with greater confidence which parameter is superior for predicting RFs after spinal fusion.

Radiation doses and accuracy of navigated pedicle screw placement in cervical and thoracic spine surgery: a comparison of sliding gantry CT and mobile cone-beam CT in a homogeneous cohort.

Multiple solutions for navigation-guided pedicle screw placement are currently available. Intraoperative imaging techniques are invaluable for spinal surgery, but often there is little attention paid to patient radiation exposure. This study aimed to compare the applied radiation doses of sliding gantry CT (SGCT)- and mobile cone-beam CT (CBCT)-based pedicle screw placement for spinal instrumentation. The authors retrospectively analyzed 183 and 54 patients who underwent SGCT- or standard CBCT-based pedicle screw placement, respectively, for spinal instrumentation at their department between June 2019 and January 2020. SGCT uses an automated radiation dose adjustment. Baseline characteristics, including the number of screws per patient and the number of instrumented levels, did not significantly differ between the two groups. Although the accuracy of screw placement according to Gertzbein-Robbins classification did not differ between the two groups, more screws had to be revised intraoperatively in the CBCT group (SGCT 2.7% vs CBCT 6.0%, p = 0.0036). Mean (± SD) radiation doses for the first (SGCT 484.0 ± 201.1 vs CBCT 687.4 ± 188.5 mGy*cm, p < 0.0001), second (SGCT 515.8 ± 216.3 vs CBCT 658.3 ± 220.1 mGy*cm, p < 0.0001), third (SGCT 531.3 ± 237.5 vs CBCT 641.6 ± 177.3 mGy*cm, p = 0.0140), and total (SGCT 1216.9 ± 699.3 vs CBCT 2000.3 ± 921.0 mGy*cm, p < 0.0001) scans were significantly lower for SGCT. This was also true for radiation doses per scanned level (SGCT 461.9 ± 429.3 vs CBCT 1004.1 ± 905.1 mGy*cm, p < 0.0001) and radiation doses per screw (SGCT 172.6 ± 110.1 vs CBCT 349.6 ± 273.4 mGy*cm, p < 0.0001). The applied radiation doses were significantly lower using SGCT for navigated pedicle screw placement in spinal instrumentation. A modern CT scanner on a sliding gantry leads to lower radiation doses, especially through automated 3D radiation dose adjustment.

A multicenter study of the 5-year trends in robot-assisted spine surgery outcomes and complications.

Although a growing amount of literature that suggests robots are safe and can achieve comparable outcomes to conventional techniques, much of this literature is limited by small sample sizes and single-surgeon or single center series. Furthermore, it is unclear what the impact of robotic technology has made on operative and clinical outcomes over time. This is the first and largest multicenter study to examine the trends in outcomes and complications after robot-assisted spine surgery over a 5-year period. Adult (≥18 years old) patients who underwent spine surgery with robot-assistance between 2015 and 2019 at four unique spine centers. The robotic systems used included the Mazor Renaissance, Mazor X, and Mazor Stealth Edition. Patients with incomplete data were excluded from this study. The minimum follow-up was 90 days. A total of 722 adult patients were included (117 Renaissance, 477 X, 128 Stealth). Most patient and operative factors (e.g., sex, tobacco status, total instrumented levels, and pelvic fixation,) were similar across the years. Mean ± standard deviation Charlson comorbidity index (CCI) was 1.5±1.5. The most commonly reported diagnoses included high grade spondylolisthesis (40.6%), degenerative disc disease (18.4%), and degenerative scoliosis (17.6%). Mean (standard deviation) number of instrumented levels was 3.8±3.4. From 2015 to 2019, average robot time per screw improved from 7.2 to 5.5 minutes (P=0.004, R2=0.649). Average fluoroscopy time per screw improved from 15.2 to 9.4 seconds (P=0.002). Rates of both intraoperative screw exchange for misplaced screw (2015-2016: 2.7%, 2019: 0.8%, P=0.0115, R2=0.1316) and robot abandonment (2015-2016: 7.1%, 2019: 1.1%, P=0.011, R2=0.215) improved significantly over time. The incidence of other intraoperative complications (e.g., dural tear, loss of motor/sensory function, blood transfusion) remained consistently low, but similar throughout the years. The length of stay (LOS) decreased by nearly 1 day from 2015 to 2019 (P=0.007, R2=0.779). 90-day reoperation rates did not change significantly. At four institutions among seven surgeons, we demonstrate robot screw accuracy, reliability, operative efficiency, and radiation exposure improved significantly from 2015 to 2019. 90-day complication rates remained low and LOS decreased significantly with time. These findings further validate continued usage of robot-assisted spine surgery and the path toward improved value-based care.

The relationship between S1 screw loosening and postoperative outcome in patients with degenerative lumbar scoliosis

BackgroundWhen choosing S1 as the lowest level of instrumentation, there are many complications may come out such as S1 screw loosening. Facing this problem, there has been various techniques for the protection of S1 screw including sacropelvic fixation, bicortical or tricortical insertion of S1 screw.ObjectiveThis study aimed to explore the risk factors for the S1 screw loosening, then to demonstrate the relationship between S1 screw loosening and postoperative outcome for patients with degenerative lumbar scoliosis (DLS).MethodsPatients who underwent lumbosacral fixation for DLS were evaluated retrospectively. They were divided into two groups according to the S1 pedicle screw at the follow-up. Age, gender, bone mineral density, body mass index, history of smoking, the number of instrumented levels, comorbidities, complications and radiological parameters were collected. We established logistic regression analysis to determine independent risk factors for S1 screw loosening and multiple linear regression to identify whether S1 screw loosening would influence postoperative clinical outcome.ResultsS1 screw loosening rate was up to 41.0% (32/78). Patients were older in the S1 screw loosening group than those in the control group (P < 0.05). Compared with the control group, the rate of osteoporosis was higher in screw loosening group than that in the control group (P < 0.05). Older age and osteoporosis were independent risk factors for S1 screw loosening (P < 0.05). In the screw loosening group, the rate of hypertension was higher than that in the control group (P < 0.05). The relationship of S1 screw loosening and ODI was not significant in the multiple linear regression (P > 0.05). The clinical outcome was similar in the S1 screw loosening group and control group (P > 0.05).ConclusionOlder age and osteoporosis are independent risk factors for the S1 screw loosening. Patients with complication of S1 screw loosening are not always along with worse clinical outcome. We should consider potential benefit, complications and medical cost when choosing the lowest instrumented vertebrae for patients with DLS.

Can intraoperative radiation dose in percutaneous posterior thoracolumbar internal fixation be reduced by impedancemetry-guided pedicle sighting? A prospective randomized study

IntroductionPercutaneous spine surgery is on the rise; the main drawback is iterative irradiation of the care team in theater. The aim of the present study was to compare intraoperative radiation dose in percutaneous posterior thoracolumbar internal fixation (PPTLIF) using impedancemetry-guided pedicle sighting by the PediGuard device (SpineGuard®) versus gold-standard free-hand sighting. Material and methodsA single-center, single-surgeon continuous prospective randomized study was conducted from September 2017 to April 2018. Dose-area product (DAP, in cGy.cm2) was recorded at the end of pedicle sighting and end of surgery in the free-hand control group and the impedancemetry group. Pedicle screw position was studied on postoperative CT scan. ResultsSixteen patients were included in either group after 2 had been excluded. The groups were comparable for age, gender, body-mass index (BMI), indication and number of instrumented levels. Mean DPA at end of sighting and end of procedure was respectively 147.4 cGy.cm2 and 230.9 cGy.cm2 in the control group and 171.1 cGy.cm2 and 280.7 cGy.cm2 in the PediGuard group (p> 0.05). Screw positioning on CT was comparable in the 2 groups. ConclusionIn the present study, the PediGuard device did not reduce intraoperative radiation dose. The correlation between radiation dose and BMI was confirmed. Level of evidenceII; prospective randomized study.

Protocol-driven early tracheal extubation in patients with flaccid neuromuscular scoliosis and pre-existing lung disease.

To review the results of a postoperative respiratory pathway for patients with muscular dystrophy (MD) and spinal muscular atrophy (SMA) undergoing spinal surgery. With IRB approval, a retrospective review was done on all patients with SMA and MD undergoing spinal surgery on a neuromuscular protocol. Baseline demographics, perioperative results, and long-term outcomes were collected. Per the protocol, patients remained intubated after surgery and were transported to the intensive care unit (ICU) for extubation. We present the results of protocol implementation and compare patients with MD to those with SMA. Twenty-four patients were treated using the protocol. Average age was 13.1years. Severe restrictive lung disease was present in 75% of patients. Nocturnal BiPAP was required in 68% of patients. Average number of instrumented levels was 17. All patients were immediately extubated upon entering the ICU. There were three respiratory complications and only was patient was re-intubated. Average ICU stay was 1.8days and average hospital length of stay was 6.7days. No differences in postoperative inspiratory or expiratory positive airway pressures were observed between the MD and SMA groups. Through a multidisciplinary neuromuscular protocol, excellent clinical outcomes were achieved in patients with neuromuscular scoliosis and restrictive lung disease, with complication rates and length of stay significantly lower than previously published data. IV.

P16. Is there a difference in screw accuracy, robot time per screw, robot abandonment, and radiation exposure between the Mazor X and the renaissance? A propensity-matched analysis of 1,179 robot-assisted screws

P16. Is there a difference in screw accuracy, robot time per screw, robot abandonment, and radiation exposure between the Mazor X and the renaissance? A propensity-matched analysis of 1,179 robot-assisted screws

43. The trends in robot related complications, operative efficiency, radiation exposure, and clinical outcomes after robot-assisted spine surgery: a multicenter study of 722 patients and 5,005 screws from 2015 to 2019

<h3>BACKGROUND CONTEXT</h3> Although there has been a growing amount of literature that suggests robots are safe and can achieve comparable outcomes to conventional techniques, much of this literature is limited by small sample sizes and single-surgeon or single center series. Furthermore, it is unclear what the impact of robotic technology has made on operative and clinical outcomes over time. This is the first and largest multicenter study to examine the trends in outcomes and complications after robot-assisted spine surgery over a 5-year period. <h3>PURPOSE</h3> To examine trends in outcomes and complications after robot-assisted spine surgery from 2015-2019. <h3>STUDY DESIGN/SETTING</h3> Multicenter cohort. <h3>PATIENT SAMPLE</h3> Adult (≥18 years old) patients who underwent robot-assisted (Mazor Renaissance, X, and Stealth) spine surgery from 2015 to 2019. <h3>OUTCOME MEASURES</h3> Outcomes of interest included operative efficiency (robot time per screw), radiation exposure (fluoroscopy time per screw), robot complications (eg, screw exchange, robot abandonment), clinical outcomes (eg, length of stay, 90-day reoperations), and other nonrobot-related complications (eg, dural tear, loss of motor/sensory function, blood transfusion). <h3>METHODS</h3> In this multicenter study, we included adult (≥18 years old) patients who underwent robot-assisted spine surgery between 2015 and 2019 at four geographically diverse institutions. The robotic systems used included the Mazor Renaissance, Mazor X, and Mazor Stealth Edition. Patients with missing data were excluded from this study. The minimum follow-up was 90 days after the index surgery. This study was approved by the institutional review board. Chi-square/fisher exact test and t-test/ANOVA were used for categorical and continuous variables, respectively. The Cochran-Armitage test was used to examine statistically significant trends. Statistical significance was defined as a P-value <0.05. SAS Studio Version 3.4 (SAS Institute Inc, Cary, NC) was used for all statistical analyses. <h3>RESULTS</h3> 722 adult patients were included (117 Renaissance, 477 X, 128 Stealth). Mean (standard deviation) Charlson comorbidity index (CCI) was 1.5 (1.5). The most common diagnoses included high grade spondylolisthesis (grade>2) (40.6%), degenerative disc disease (18.4%), and degenerative scoliosis (17.6%). Mean (standard deviation) number of instrumented levels was 3.8(3.4). Most patient and operative factors (eg, gender, smoking status, total instrumented levels, and pelvic fixation,) were similar across the years. From 2015-2019, mean robot time per screw decreased from 7.2 minutes to 5.5 minutes (P=0.004, R2=0.65). Mean fluoroscopy time per screw decreased from 15.2 seconds to 9.4 seconds (P=0.002, R2=0.83). Rates of both intraoperative screw exchange for misplaced screw (2015-2016: 2.7%, 2019: 0.8%, P=0.0115, R2=0.13) and robot abandonment (2015-2016: 7.1%, 2019: 1.1%, P=0.011, R2=0.22) improved significantly over time. The incidence of other intraoperative nonrobot related complications (eg, dural tear, loss of motor/sensory function, blood transfusion) remained consistently low, but similar between years. The LOS decreased by nearly 1 day from 2015-2019(P=0.007, R2=0.78). 90-day reoperation rates did not change significantly. <h3>CONCLUSIONS</h3> Current trends demonstrate that robot screw accuracy, reliability, operative efficiency, and radiation exposure have improved significantly over the last five years. This is likely the result of increased surgeon experience with robots and the recent advances in robotic technology. The 90-day surgical complication rates remain consistently low and the mean length of stay has reduced significantly with time, which may offset the cost of robot-assisted spine surgery; however, future work specifically focusing on cost analyses are needed. Nevertheless, these findings further validate the continued usage of robot-assisted spine surgery and the potential path toward improved value-based care. <h3>FDA DEVICE/DRUG STATUS</h3> Medtronic Renaissance, Mazor X and Mazor X stealth are FDA approved in the US.

Value in Scoliosis Surgery: Coordinated Surgical and Anesthetic Techniques Avoid Blood Transfusion without Fibrinolytic Medications or Red Blood Cell Salvage.

Retrospective chart review. The aim of this study was to document the impact of coordinated surgical and anesthetic techniques on estimated blood loss (EBL) and subsequent need for transfusion. Scoliosis surgery is typically associated with large quantities of blood loss, and consequently blood transfusion may be necessary. Many strategies have been employed to minimize blood loss, including blood collection with reinfusion ("cell-saver") and the use of antifibrinolytic drugs. We reviewed our experience with methods to minimize blood loss to show that transfusion should be a rare event. One hundred and thirty consecutive cases of spine fusion for adolescent idiopathic scoliosis utilizing pedicle screw fixation were reviewed from March 2013 to October 2019. The senior author was the primary surgeon for all cases. Data were collected from the electronic medical record, including age, sex, weight, number of instrumented levels, EBL, total fluids administered during surgery, pre- and postoperative hemoglobin, and procedure duration. The average EBL was 232 ± 152 mL (range 37-740 mL). The average preoperative hemoglobin was 13.4 ± 1.2 g/dL and the average postoperative hemoglobin (last measured before discharge) was 9.0 ± 1.2 g/dL. One patient received a transfusion of 270 mL homologous blood. Blood salvage and reinfusion ("cell-saver") was not used. No patient was managed with antifibrinolytic drugs. Minimizing blood loss using a combination of surgical and anesthesia techniques can effectively eliminate the need for blood transfusion. The elimination of costly adjuncts increases the value of a complex orthopedic procedure.Level of Evidence: 5.

Preoperative CT Angiography Informs Instrumentation in Anterior Spine Surgery for Idiopathic Scoliosis

Introduction:The objective of this study is to evaluate whether the artery of Adamkiewicz localization with preoperative CT angiography influences anterior spinal instrumentation.Methods:Children with idiopathic scoliosis who underwent anterior instrumentation and with a preoperative CT angiography were evaluated retrospectively. Data included curve type, artery of Adamkiewicz level/laterality, surgical approach laterality, number of instrumented levels and segmental vessels ligated, intraoperative neuromonitoring changes, and postoperative neural complications.Results:Thirty-nine girls and eight boys (mean age 12 years [6.7 to 16.8 years]) were analyzed. Instrumented curves indicate 28 thoracic, 14 thoracolumbar, and seven double major. The artery of Adamkiewicz: T6 (left-1), T8 (left-1), T9 (left-4/right-2), T10 (left-11/right-4), T11 (left-4/right-4), T12 (left-1/right-2), L1 (left-2/right-1), and L2 (left-3/right-2). Four had bilateral dominant segmentals, whereas in nine patients, none was identified. T10 (32%) and left side (57%) were most frequent. On average, 7.1 (4 to 11) segmentals were ligated per case (total 355). Dominant vessels were ipsilateral to/within instrumentation levels in 30%.Discussion:In children with idiopathic scoliosis who underwent anterior instrumentation, the artery of Adamkiewicz was identified on the left in >50% and at T10 in 32%. In one-third of the patients, the artery was within intended surgical levels and resulted in instrumentation modification.

Surgical treatment of traumatic thoracolumbar fractures: a retrospective review of 101 cases.

To evaluate the outcomes of vertebral stabilisation after acute traumatic thoracolumbar fractures, correlating the outcome with patient clinical data, type and location of fracture, presence of neurological damage, timing of surgical intervention and number of instrumented levels. The results have been evaluated also through the AO classification and AOSIS score. Retrospective analysis of 101 patients with traumatic thoracolumbar injuries from T3 to L5 operated 2011-2016 by posterior or antero-posterior fixation. The demographic data, trauma dynamics, number and type of fractures, associated lesions, timing of surgery, hospital stay, AOSIS score, RKA, SF-36 and ODI scores, pre- and post-operative neurological condition (ASIA grade), possible complications and re-interventions were evaluated for each patient. Fractures mainly involved the region between T11 and L2. The probability of medullary involvement increases with the increase in severity of the main fracture type with no relation with the vertebral region. Type B and C fractures were common in the thoracic region and rare in the thoracolumbar junction. ODI and SF-36 scores were significantly better in patients with a lower AOSIS score, specifically in lesions classified as type A, amyelic and with no comorbidity. No difference was found in the clinical scores between thoracic, thoracolumbar and lumbar fractures, nor between male and female patients. None of the 10 patients with ASIA A lesion at presentation achieved any degree of recovery: 50% of them had a thoracic lesion. Re-intervention rate was 15%. Hospital stay was significantly higher in patients with type C fractures, and complication rate was on average 14% (7% in type A fractures, 16% in B and 25% in C). This study confirmed the validity of the posterior approach in the surgical treatment of thoracolumbar fractures. Outcomes and complication risks are related to fracture severity. Surgical treatment can be recommended even with an AOSIS score of two or three. The combined antero-posterior approach could be useful in cases with LSC > 8, especially in the thoracolumbar region. The degree of neurological recovery depends on fracture type, location, ASIA score and presence of comorbidities. Early intervention in myelic patients allows for a better prognosis. Level of evidence III retrospective case series.

Inpatient Outcomes of Surgical Treatment for Spinal Tuberculosis: 10-Year Results from the US National Inpatient Sample.

To evaluate the association between in-hospital outcomes of patients with spinal tuberculosis and different surgical approaches. This population-based, retrospective observational study analyzed data of hospitalized patients undergoing surgical treatment for spinal tuberculosis in the United States who were identified in the US Nationwide Inpatient Sample (NIS) between 2005 and 2014. The study cohort was stratified by posterior-only, anterior-only, and combined surgical approaches. Logistic and linear regression analyses were performed to evaluate associations between surgical approaches and patient outcomes. Significant differences were found in postoperative complications, number of instrumented levels, and comorbidity scores (all p ? 0.033) between patients who received different surgical approaches. A univariate analysis demonstrated the combined approach was associated with significantly increased odds of postoperative complications compared with the posterior-only approach. This association remained significant when following multivariate analysis after adjustments. For patients who received surgery at the lumbosacral level, the anterior-only approach and combined approach were both associated with significantly increased odds of postoperative complications compared with the posterior-only approach. Among patients who received surgery at the lumbosacral level, multivariate analysis showed that anterior-only and combined approaches were associated with significantly longer length of stay. Among patients with spinal tuberculosis who are undergoing surgical treatment, a posterior-only approach was associated with fewer complications and shorter length of stay compared with an anterior-only or combination approaches when performed at the lumbo-sacral spinal level.

The clinical and radiological outcomes of multilevel posterior lumbar interbody fusion in the treatment of degenerative scoliosis: a consecutive case series with minimum 2 years follow up.

Surgical treatment for adult degenerative scoliosis (ADS) is a complex undertaking and is associated with a high complication rate. Our aim was to evaluate the clinical and radiological outcomes, mortality and morbidity of multilevel posterior lumbar interbody fusion (MPLIF) in the treatment in ADS based on the experience of a single tertiary referral center for spinal surgery. We performed a retrospective analysis of prospectively collected data of consecutive patients who had undergone multi-level posterior interbody fusion for degenerative scoliosis. We prospectively recorded patients' demographics, co-morbidities; coronal and sagittal plane deformity assessment and surgical details: number of instrumented levels, and intra-operative and postoperative complications. Functional outcomes and patient-reported complications were entered in our local spine surgery database (part of the Eurospine Spine Tango Registry) and used to collect data on functional scores and patient-reported complications preoperatively and at 6, 12 and 24 months' follow-up. Our study involved 13 males and 51 females with a mean age of 70.26 (range 49-90, SD 8.9). MPLIF was performed at five levels in one patient, four levels in 29 patients, three levels in 20 patients, and two levels in 14 patients. There were a total of 14 (21.87%) major, minor and mechanical complications. There were no procedure-related mortalities. The average COMI and Eq5d scores improved significantly post-surgery, and this improvement was maintained at a mean follow-up of up to two years. Multilevel posterior interbody fusion is a safe procedure, and in selected cases can result in good clinical and radiological outcomes with improvement in patient quality of life.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P86. ROTEM-guided transfusion during pedicle subtraction osteotomy for adult spinal deformity: a propensity score-matched cohort analysis

BACKGROUND CONTEXT Surgical correction of adult spinal deformity (ASD) is often associated with significant blood loss and coagulopathy. Optimal intraoperative transfusion algorithm remains debatable. Rotational thromboelastometry (ROTEM), a functional viscoelastometric method for real-time hemostasis testing, may allow early identification of coagulopathy, and hence improve transfusion practices during surgery. PURPOSE To investigate the effects of ROTEM-guided therapy on intraoperative estimated blood loss (EBL) and transfusion requirements in patients who underwent pedicle subtraction osteotomy (PSO) for ASD. STUDY DESIGN/SETTING Retrospective chart review of a prospectively maintained, single-center, multisurgeon database. PATIENT SAMPLE Consecutive ASD patients. OUTCOME MEASURES Primary outcomes: intraoperative EBL and total volume of blood product transfused. Secondary outcomes: packed red blood cells (pRBC), platelets, cryoprecipitate, and fresh frozen plasma (FFP) transfused during surgery. METHODS All ASD patients who underwent single-level lumbar PSO with ROTEM-guided transfusion at our institution were matched in a 1:1 ratio to a historical cohort with the conventional clinical and point-of-care (POC) transfusion algorithm. Covariates for matching were age, body mass index, revision operation status, number of instrumented levels, number of transforaminal lumbar interbody fusions, number of Smith-Petersen osteotomies, and preoperative hemoglobin. RESULTS The matched groups comprised 17 patients each, and comparison of baseline demographic and surgical parameters demonstrated more women (p=.04) and a higher total intraoperative dose of intravenous tranexamic acid (TXA) administered (p=.03) in the ROTEM group. Although not significant, EBL was lower in the ROTEM group (3200.00±2106.24vs. 3874.12±2224.22 mL; p=.36), with small-to-medium effect size (Cohen's d=0.31). Prior to adjusting for TXA, ROTEM-based transfusion was associated with lower volume of total blood products transfused (1624.18±1774.79vs. 2810.88±1847.46 mL; p=.02), with medium-to-large effect size (Cohen's d=0.66). This difference was no longer significant after adjustment for TXA (β=−0.18; 95% CI [−1995.78 to 671.64]; p=.32). pRBC and platelet transfusions were comparable between the matched cohorts. The ROTEM group was associated with greater number of cryoprecipitate units (1.24±1.20vs. 0.53±1.01 units; p=.03) and lower FFP (119.76±230.82vs. 673.06±627.08 mL; p CONCLUSIONS Compared to the conventional transfusion criteria, the use of ROTEM-guided transfusion algorithm in lumbar PSO for surgical correction of ASD was associated with greater number of cryoprecipitate units and lower FFP volume transfused. ROTEM-guided transfusion allowed early identification and treatment of hypofibrinogenemia, and aggressive management of this complication may reduce intraoperative EBL and total volume of blood products transfused.

Construct Levels to Anchored Levels Ratio and Rod Diameter Are Associated With Implant-Related Complications in Traditional Growing Rods

IntroductionIn addition to patient characteristics, consideration of length of construct to number of anchored levels ratio and rod diameter should be a part of preoperative planning to minimize implant-related complications (IRCs). IRCs including rod breakage, anchor dislodgement, and pullout are among the most common adverse events in traditional growing rods (TGRs). The current study hypothesized that anchor type and configuration are associated with IRC. MethodsPatients with (1) age ≤10 years at surgery; (2) spine-based dual TGR; (3) minimum 2-year follow-up; and (4) available imaging. Cephalad and caudal foundations were grouped based on the number of instrumented levels and anchor type. All radiographs were reviewed. Based on the results, a “construct levels / anchored levels” (CL/AL) ratio was calculated, which is the number of levels spanned by instrumentation divided by the number of levels with bone-anchor fixation. Receiver operating characteristic curve was used to define the CL/AL threshold. Results274 patients divided into patients with complications (IRC+, n = 140) and without complications (IRC–, n = 134) groups. Mean follow-up was 6.3 years (2.1–18.0 years). No significant differences in age, gender, body mass index, ambulatory status, etiology, primary curve size, T1–S1 height, coronal and sagittal balance, and rod material were observed between the two groups. Comparative analysis showed that connector type, presence and location of crosslinks, number of levels instrumented, number and type of anchors, presence of pelvic fixation, and mirroring of cephalad and caudal foundations were not different. However, maximum kyphosis and rod diameter were significantly different. The CL/AL ratio threshold was 3.5. Multivariate analysis of kyphosis, rod diameter, and CL/AL ratio showed a significant association with IRC (p < .05). Discussion and ConclusionAlthough patient characteristics like kyphosis have been proven to be associated with instrumentation failure, it is a combination of characteristics that include rod diameter and CL/AL ratio that showed significant correlation with IRC. Validation of the CL/AL ratio is recommended.

Efficacy of Intraoperative Neurophysiologic Monitoring for Pediatric Cervical Spine Surgery

Clinical case series. To investigate the efficacy of intraoperative neuromonitoring in pediatric cervical spine surgery. Intraoperative neuromonitoring (IONM) consisting of somatosensory-evoked potentials (SSEP) and transcranial motor-evoked potentials (tcMEP) has been shown to effectively prevent permaneny neurologic injury in deformity surgery. The role of IONM during pediatric cervical spine surgery is not well documented. Advances in cervical spine instrumentation have expanded the surgical options in pediatric populations. The goal of this study is to report the ability of IONM to detect neurologic injury during pediatric cervical spine instrumentation. A single institution database was queried for pediatric-aged patients who underwent cervical spine instrumentation and fusion between 2011 and 2014. Age, diagnosis, surgical indication, number of instrumented levels, and a complete IONM were extracted. Sensitivity and specificity for the detection of neurologic deficits were calculated with exact 95% confidence intervals. Positive and negative predictive values were calculated with estimated 95% confidence intervals. Sixty-seven patients who underwent cervical spine instrumentation were identified with a mean age of 11.6 years (range 1-18). Diagnoses included instability (27), congenital (11), kyphosis (8), fracture (7), tumor (7), arthritis (4), and basilar invagination (3). Mean number of vertebral levels fused was 4 (range 2-7). All patients underwent cervical instrumentation with SSEP and tcMEP monitoring. A significant change in tcMEP monitoring was observed in 7 subjects (10%). There were no corresponding SSEP changes in these patients. The sensitivity of combined IONM was 75% [95% CI = 24.9, 98.7] and the specificity was 98.5% [92.7, 99.9]. tcMEP is a more sensitive indicator to spinal cord injury than SSEP, which is consistent with previous studies. IONM changes in 10% of a patient population are significant enough to warrant intraoperative determination if true SCI has occurred or is underway and intervene accordingly. 4.

Minimally invasive spinal surgery for the management of symptomatic spinal metastasis

Introduction: Symptomatic metastatic spinal disease is on the increase. Minimally invasive spinal surgery has been associated with a lower complication profile when compared to traditional open methods; however there is paucity of literature evaluating the place of percutaneous pedicle screw fixation (PPSF) in the management of spinal metastases. The purpose of the study is to assess the efficacy of Minimally Invasive Spine Surgery (MISS) using PPSF with or without mini-decompression in the management of symptomatic spinal metastases.Material and Methods: This is a single institution prospective study of 51 consecutive patients with metastatic spinal disease treated with PPSF. Patients presenting with pathological compression fractures and mechanical instability had PPSF, and those with radiological and/or clinical metastatic spinal cord compression (MSCC) underwent an additional mini-decompression. Data collected included patient demographics, Karnofsky’s performance status (KPS), pain scores and neurology. Other data included number and location of involved levels, number of instrumented levels, blood loss, accuracy of screw placement and complications.Results: Of the 51 patients, 49 could be successfully treated with MISS (26 females and 23 males). 26 patients (55%) required a mini-decompression. 27 patients (55%) had improvement in KPS by at least 10 points (p < 0.0005). Only 2 patients (4%) had a worsening of KPS, due to other coexisting problems. Six of the 13 patients improved their neurology by one Frankel grade following surgery and 95% reported improvement in pain. Mean blood loss was 92mls for the fixation only group and 222mls for those requiring mini-decompression, with no other differences between these two surgical groups. Screw positioning was excellent in 91%, with 98% having uncompromised bony hold. Only two patients required revision surgery for aseptic loosening.Conclusion: MISS using PPSF is a safe and reproducible technique that maintains or improves functional outcome in the vast majority of patients presenting with spinal metastases.