Complications Have Not Improved With Newer Generation Robots.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose of this study was to see whether upgrades in newer generation robots improve safety and clinical outcomes following spine surgery. METHODS: All patients undergoing robotic-assisted spine surgery with the Mazor X Stealth EditionTM (Medtronic, Minneapolis, MN) from 2019 to 2022 at a combined orthopedic and neurosurgical spine service were retrospectively reviewed. Robot related complications were recorded. RESULTS: 264 consecutive patients (54.1% female; age at time of surgery 63.5 ± 15.3 years) operated on by 14 surgeons were analyzed. The average number of instrumented levels with robotics was 4.2 ± 2.7, while the average number of instrumented screws with robotics was 8.3 ± 5.3. There was a nearly 50/50 split between an open and minimally invasive approach. Six patients (2.2%) had robot related complications. Three patients had temporary nerve root injuries from misplaced screws that required reoperation, one patient had a permanent motor deficit from the tap damaging the L1 and L2 nerve roots, one patient had a durotomy from a misplaced screw that required laminectomy and intra-operative repair, and one patient had a temporary sensory L5 nerve root injury from a drill. Half of these complications (3/6) were due to a reference frame error. In total, four patients (1.5%) required reoperation to fix 10 misplaced screws. CONCLUSION: Despite newer generation robots, robot related complications are not decreasing. As half the robot related complications result from reference frame errors, this is an opportunity for improvement.

Catastrophic acute failure of pelvic fixation in adult spinal deformity requiring revision surgery: a multicenter review of incidence, failure mechanisms, and risk factors.

OBJECTIVE: There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS: Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS: Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence-lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5-S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS: Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Trends and Long-term Health Care Utilization of Computer-assisted Neuronavigation in Spine Fusions: An Exact Matched Analysis of National Administrative Database.

BACKGROUND: Computer-assisted neuronavigation (CAN) during spine fusions has increasingly been utilized in the United States. The aim of this study was to analyze the trends, health care utilization, and clinical outcomes associated with CAN use. METHODS: The MarketScan database was queried using the ICD-9/10 and CPT 4th edition, from 2003 to 2019. We included patients aged ≥18 years with at least 2 years of follow-up. Outcomes were repeat/new fusions, length of stay (LOS), discharge disposition, hospital re-admissions, outpatient services, and medication refills for up to 24 months. RESULTS: Of 183,620 patients who underwent spine fusions, 5046 (2.75%) were identified to have CAN utilized. CAN is increasingly being utilized for spine fusions since 2010, reaching 10.76% of all fusions in 2017, compared to 0.38% in 2010. CAN had no impact on LOS, home discharge, or complications at index hospitalization and 30-days post discharge. CAN was associated with lower rates of repeat fusions at 6 months (1% vs. 2%) and 24 months (5% vs. 6%), P < 0.05. Patients who underwent CAN had lower payments at 6 months ($5186 vs. $5527, P = 0.0159), 12 months ($10,267 v.s $11,262, P = 0.0207), and 24 months ($21,453 vs. $24,355, P = 0.0021). CONCLUSIONS: CAN is increasing being used for spine fusions primarily for thoracolumbar procedures. No difference in complications, discharge disposition, and LOS were noted across the cohorts at index hospitalization, with higher index payments with CAN use. CAN was associated with lower rates of repeat fusions and corresponding health care utilization for up to 24 months.

Extensive spontaneous cervical epidural hematoma due to oral anticoagulant (dabigatran) successfully treated with reversal agent idarucizumab alone.

Background: Dabigatran is an anticoagulant (novel oral anticoagulant) that is a direct thrombin inhibitor and only recently has a reversal agent, idarucizumab, been made available (2015). Case Description: An 86-year-old male taking dabigatran for atrial fibrillation, acutely presented with the spontaneous onset of neck pain and quadriparesis. When the MRI demonstrated a C2-T2 spinal epidural hematoma, the patient was given the reversal agent idarucizumab. Due to his attendant major comorbidities, he was managed nonoperatively. Over the next 7 days, the patient's neurological deficits resolved, and within 2 weeks, he had regained normal neurological function. Conclusion: In this case, a C2-T2 epidural cervical hematoma attributed to dabigatran that was responsible for an acute, spontaneous quadriparesis was successfully treated with the reversal agent idarucizumab without surgical intervention being warranted.

Epidural hematoma in patients with ankylosing spondylitis requiring surgical stabilization: a single-institution retrospective review with literature analysis.

OBJECTIVE: Ankylosing spondylitis (AS) is a chronic inflammatory disease affecting the sacroiliac joints and axial spine that is closely linked with human leukocyte antigen-B27. There appears to be an increased frequency of associated epidural hematomas in spine fractures in patients with AS. The objective was to review the incidence within the literature and a single-institution experience of the occurrence of epidural hematoma in the context of patients with AS requiring spine surgery. METHODS: Deep 6 AI software was used to search the entire database of patients at a single level I trauma center (since the advent of the institution's modern electronic health record system) to look at all patients with AS who underwent spinal surgery and who had a diagnosis of epidural hematoma. Additionally, a systemic literature review was performed of all papers evaluating the incidence of epidural hematoma in patients with spine fractures. RESULTS: A single-institution, retrospective review of records from 2009 to 2020 yielded a total of 164 patients with AS who underwent spine surgery. Of those patients, 17 (10.4%) had epidural hematomas on imaging, with the majority requiring surgical decompression. These spine fractures occurred close to the cervicothoracic or thoracolumbar junction. The patients ranged in age from 51 to 88 years, and there were 14 males and 3 females in the cohort. Eight patients were administered an antiplatelet and/or anticoagulant agent, and the rest were not. All patients required surgical stabilization, with 64.7% of patients also requiring decompressive laminectomies for evacuation of the hematoma and spinal cord decompression. Only 1 death was reported in the series. There was a tendency toward neurological improvement after surgical intervention. CONCLUSIONS: AS has been a well-described pathologic process that leads to an increased risk of three-column injury in spine fracture, with an increased incidence of symptomatic epidural hematoma compared with patients without AS. Early recognition of this entity is important to ensure that appropriate surgical management includes addressing compression of the neural elements in addition to surgical stabilization.

Video-assisted thoracoscopic image-guided spine surgery: evolution of 19 years of experience, from endoscopy to fully integrated 3D navigation.

OBJECTIVE: The purpose of this study was to describe the evolution of thoracoscopic spine surgery from basic endoscopic procedures using fluoroscopy and anatomical localization through developmental iterations to the current technology use in which endoscopy and image-guided surgery are merged with intraoperative CT scanning. METHODS: The authors provided detailed explanations of their thoracoscopic spine surgery techniques, beginning with their early-generation endoscopy with fluoroscopic localization, which was followed with point surface matching techniques and early image guidance. The authors supplanted this with the modern era of image guidance, thoracoscopic spine surgery, and seamless integration that has reached its current level of refinement. RESULTS: A retrospective review of single-institution thoracoscopic procedures performed by the senior author over the course of 19 years yielded a total of 160 patients, including 73 women and 87 men. The mean patient age was 55 years, and the range included patients 16-94 years of age. There were no patients with worsened neurological function. One hundred sixteen patients underwent surgery for thoracic disc herniation, 18 for underlying neoplasms with spinal cord compression, 14 for osteomyelitis and discitis, 12 for thoracic deformity with neurological changes, and 8 for traumatic etiologies. CONCLUSIONS: More than 19 years of experience has revealed the benefits of integrating thoracoscopic spine surgery with intraoperative CT scanning and image-guided surgery, including direct decompression without manipulation of neural elements, superior 3D spatial orientation, and localization of complex spinal anatomy. With the exponential growth of machine learning, robotics, artificial intelligence, and advances in imaging techniques and endoscopic imaging, there may be further refinements of this technique on the horizon.

Two-level cervical disc arthroplasty in patients with Klippel-Feil syndrome: A case report and review of the literature.

BACKGROUND: Klippel-Feil syndrome (KFS) is defined by multiple abnormal segments of the cervical spine with congenital synostosis of two or more cervical vertebrae. KFS patients who demonstrate progressive symptomatic instability and/or neurologic sequelae are traditionally managed with operative decompression and arthrodesis. CASE DESCRIPTION: A 44-year-old female with chronic neck pain and radiculopathy and a C7-T1 KFS presented with adjacent segment degenerative disc disease at the C5-6 and C6-7 levels. She was successfully managed with a two-level cervical disc arthroplasty (CDA). CONCLUSION: Patients with KFS and disease at two contiguous, adjacent levels (e.g., cervical disc disease) may be safely and effectively managed with two-level CDA.

Is magnetic resonance imaging becoming the new computed tomography for cervical spine clearance? Trends in magnetic resonance imaging utilization at a Level I trauma center.

BACKGROUND: Increasing evidence supports the limited use of magnetic resonance imaging (MRI) for cervical spine (C-spine) clearance following blunt trauma. We sought to characterize the utilization of MRI of the C-spine at a Level I trauma center. METHODS: All blunt trauma patients undergoing a computed tomography (CT) of the C-spine between January 2009 and December 2018 were reviewed. The CT and MRI results, demographics, clinical presentation, subspecialty consultations, and interventions were recorded. The MRI results were considered clinically significant if they resulted in cervical thoracic orthosis/halo placement or surgical intervention. Linear regression models were utilized to identify trends. RESULTS: There were 9,101 patients that underwent a CT of the C-spine, with 513 (5.6%) being positive for an acute injury. MRI was obtained for 375 (4.1%) of patients. A linear increase in the proportion of patients undergoing an MRI was noted, from 0.9% in 2009 to 5.6% in 2018 (p < 0.01). Of the 513 patients with a positive CT, 290 (56.5%) had an MRI. In 40 (13.8%) of them, the CT demonstrated a minor injury. Clinically significant MRI findings were noted only in two (5.0%) of the 40 patients, and both had a neurologic deficit on initial examination. Of the 8,588 patients with a negative CT, 85 (1.0%) underwent an MRI. Of those, 9 (10.6%) had a clinically significant MRI with all but one presenting with a neurological deficit. CONCLUSION: MRI is increasingly utilized for C-spine clearance following blunt trauma. MRI was exceedingly unlikely to demonstrate a clinically significant finding in the absence of a neurological deficit, when the CT was negative or included minor injuries. Trauma centers are encouraged to constantly evaluate their own practices and intervene with education and collaboration to limit the excessive use of unnecessary resources. LEVEL OF EVIDENCE: Therapeutic/Care Management Study, Level III or IV. Diagnostic test, level IV.

Severe Chin-on-Chest Cervical Spine Deformity in the Setting of Stiff-Person Syndrome: A Case Report.

CASE: Stiff-person syndrome (SPS) presents with progressive muscle rigidity, postural instability, and periodic debilitating spasms. Reports of axial hyperextension exist, but kyphotic deformities have not been described. We surgically treated a patient with debilitating SPS and severe cervicothoracic hyperkyphosis with posterior spinal fusion and instrumentation. At 1-year follow-up, the patient displayed better upright gait and forward gaze, 18° cervical lordosis, and improved patient-reported outcome scores. CONCLUSION: SPS can lead to extreme spinal deformity and disease, including hyperkyphosis of the cervicothoracic spine, and can successfully be managed with a multidisciplinary team and a posterior-only correction with spinal instrumentation and fusion.

Intraoperative navigation-guided resection of anomalous transverse processes in patients with Bertolotti's syndrome.

BACKGROUND: Bertolotti's syndrome is characterized by enlargement of the transverse process at the most caudal lumbar vertebra with a pseudoarticulation between the transverse process and sacral ala. Here, we describe the use of intraoperative three-dimensional image-guided navigation in the resection of anomalous transverse processes in two patients with Bertolotti's syndrome. CASE DESCRIPTIONS: Two patients diagnosed with Bertolotti's syndrome who had undergone the above-mentioned procedure were identified. The patients were 17- and 38-years-old, and presented with severe, chronic low back pain that was resistant to conservative treatment. Imaging revealed lumbosacral transitional vertebrae at the level of L5-S1, which was consistent with Bertolotti's syndrome. Injections of the pseudoarticulations resulted in only temporary symptomatic relief. Thus, the patients subsequently underwent O-arm neuronavigational resection of the bony defects. Both patients experienced immediate pain resolution (documented on the postoperative notes) and remained asymptomatic 1 year later. CONCLUSION: Intraoperative three-dimensional imaging and navigation guidance facilitated the resection of anomalous transverse processes in two patients with Bertolotti's syndrome. Excellent outcomes were achieved in both patients.

National trends following decompression, discectomy, and fusion in octogenarians and nonagenarians.

BACKGROUND: The National Inpatient Sample (NIS) database is used to evaluate a wide variety of surgical procedures across a range of specialties. The authors of this study assess national trends of the three commonest spine procedures performed (decompression, fusion, and discectomy) in patients between the ages of 80 and 100 years (octogenarians and nonagenarians). METHODS: The NIS database was queried to identify patients between the ages of 80 and 100 with a primary diagnosis of spinal stenosis, disk herniation without myelopathy, or protrusion due to degeneration of spine/disk disorders and who have undergone spinal decompression, fusion, or discectomy between the years 1998 and 2011. Variables of concern included length-of-stay (LOS), non-routine discharge, average total charges, in-hospital complications, and mortality rate. RESULTS: Decompression was the most common procedure performed (n = 113,267, 50.5%). Fusion (n = 60,345, 26.9%) was associated with the longest LOS (5.1 days), highest in-hospital complication and mortality rates (n = 13,170, 21.8% and n = 449, 0.7%, respectively), most non-routine discharges (n = 42,662, 70.7%), and highest mean for average total charges ($69,295) (p < 0.001). Discectomy (n = 50,740, 22.6%), had the shortest LOS (3.7 days), lowest complication and mortality rates (n = 6823, 13.4% and n = 102, 0.2%, respectively), fewest non-routine discharges (n = 22,861, 45.1%), and lowest mean for average total charges ($22,787) (p < 0.001). CONCLUSIONS: Decompression was most common. Fusion had the longest LOS, highest complication and mortality rates, most non-routine discharges, and was most expensive. Discectomy was least commonly performed, had the shortest LOS, lowest complication and mortality rates, fewest non-routine discharges, and was least expensive.

Image-guided resection of aggressive sacral tumors.

OBJECTIVE The aim of this study was to identify and discuss operative nuances utilizing image guidance in the surgical management of aggressive sacral tumors. METHODS The authors report on their single-institution, multi-surgeon, retrospective case series involving patients with pathology-proven aggressive sacral tumors treated between 2009 and 2016. They also reviewed the literature to identify articles related to aggressive sacral tumors, their diagnosis, and their surgical treatment and discuss the results together with their own experience. Information, including background, imaging, treatment, and surgical pearls, is organized by tumor type. RESULTS Review of the institutional records identified 6 patients with sacral tumors who underwent surgery between 2009 and 2016. All 6 patients were treated with image-guided surgery using cone-beam CT technology (O-arm). The surgical technique used is described in detail, and 2 illustrative cases are presented. From the literature, the authors compiled information about chordomas, chondrosarcomas, giant cell tumors, and osteosarcomas and organized it by tumor type, providing a detailed discussion of background, imaging, and treatment as well as surgical pearls for each tumor type. CONCLUSIONS Aggressive sacral tumors can be an extremely difficult challenge for both the patient and the treating physician. The selected surgical intervention varies depending on the type of tumor, size, and location. Surgery can have profound risks including neural compression, lumbopelvic instability, and suboptimal oncological resection. Focusing on the operative nuances for each type can help prevent many of these complications. Anecdotal evidence is provided that utilization of image-guided surgery to aid in tumor resection at our institution has helped reduce blood loss and the local recurrence rate while preserving function in both malignant and aggressive benign tumors affecting the sacrum.

Scoliosis surgery in the elderly: Complications, readmissions, reoperations and mortality.

The operative management of scoliosis in the elderly remains controversial. The authors of this study sought to evaluate outcomes in elderly patients with scoliosis undergoing deformity correction. Patient data was obtained from a 5% sample of the Medicare Provided Analysis and Review database (MEDPAR). Patients over 65years of age with scoliosis undergoing corrective surgery were identified between the years 2005 to 2011. A total of 453 patients were analyzed: 262 (57%) between ages 66 to 74years, and 191 (42%) over the age of 75years. Female predominance (78%) was observed in this sample. Pre-diagnosis follow-up averaged 118months. Post-surgery follow-up averaged 33months. Patients between 66 and 74years old were mostly discharged home, while patients over the age of 75years were discharged to skilled nursing facilities (SNFs) (38.55% versus 34.04%, p value=0.0011). Readmission rates were lower in patients between 66 and 74years old when compared to patients over the age of 75years (9.92% versus 17.28%, p value=0.0217). Complication rates 30-days after discharge were less in patients between 66 and 74years, compared to those over 75years (21% versus 26.6%, respectively), but this was not statistically significant. These findings suggest varying outcomes following scoliosis surgery in the elderly, but interpretation of these results is weakened by the inherent limitations of database utilization. Future prospective studies are needed to understand risk factors and other confounding variables, such as discharge disposition, that may influence outcomes.

Resection of spinal column tumors utilizing image-guided navigation: a multicenter analysis.

OBJECTIVE The use of intraoperative stereotactic navigation has become more available in spine surgery. The authors undertook this study to assess the utility of intraoperative CT navigation in the localization of spinal lesions and as an intraoperative tool to guide resection in patients with spinal lesions. METHODS This was a retrospective multicenter study including 50 patients from 2 different institutions who underwent biopsy and/or resection of spinal column tumors using image-guided navigation. Of the 50 cases reviewed, 4 illustrative cases are presented. In addition, the authors provide a description of surgical technique with image guidance. RESULTS The patient group included 27 male patients and 23 female patients. Their average age was 61 ± 17 years (range 14-87 years). The average operative time (incision to closure) was 311 ± 188 minutes (range 62-865 minutes). The average intraoperative blood loss was 882 ± 1194 ml (range 5-7000 ml). The average length of hospitalization was 10 ± 8.9 days (range 1-36 days). The postoperative complications included 2 deaths (4.0%) and 4 radiculopathies (8%) secondary to tumor burden. CONCLUSIONS O-arm 3D imaging with stereotactic navigation may be used to localize lesions intraoperatively with real-time dynamic feedback of tumor resection. Stereotactic guidance may augment resection or biopsy of primary and metastatic spinal tumors. It offers reduced radiation exposure to operating room personnel and the ability to use minimally invasive approaches that limit tissue injury. In addition, acquisition of intraoperative CT scans with real-time tracking allows for precise targeting of spinal lesions with minimal dissection.

Outcomes and National Trends for the Surgical Treatment of Lumbar Spine Trauma.

Introduction. Operative treatment of lumbar spine compression fractures includes fusion and/or cement augmentation. Our aim was to evaluate postoperative differences in patients treated surgically with fusion, vertebroplasty, or kyphoplasty. Methods. The Nationwide Inpatient Sample Database search for adult vertebral compression fracture patients treated 2004-2011 identified 102,316 surgical patients: 30.6% underwent spinal fusion, 17.1% underwent kyphoplasty, and 49.9% underwent vertebroplasty. Univariate analysis of patient and hospital characteristics, by treatment, was performed. Multivariable analysis was used to determine factors associated with mortality, nonroutine discharge, complications, and patient safety. Results. Average patient age: fusion (46.2), kyphoplasty (78.5), vertebroplasty (76.7) (p < .0001). Gender, race, household income, hospital-specific characteristics, and insurance differences were found (p ≤ .001). Leading comorbidities were hypertension, osteoporosis, and diabetes. Risks for higher mortality (OR 2.0: CI: 1.6-2.5), nonroutine discharge (OR 1.6, CI: 1.6-1.7), complications (OR 1.1, CI: 1.0-1.1), and safety related events (OR 1.1, CI: 1.0-1.1) rose consistently with increasing age, particularly among fusion patients. Preexisting comorbidities and longer in-hospital length of stay were associated with increased odds of nonroutine discharge, complications, and patient safety. Conclusions. Fusion patients had higher rates of poorer outcomes compared to vertebroplasty and kyphoplasty cohorts. Mortality, nonroutine discharge, complications, and adverse events increased consistently with older age.

Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation.

We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy.

Simultaneous Lateral Interbody Fusion and Posterior Percutaneous Instrumentation: Early Experience and Technical Considerations.

Lumbar fusion surgery involving lateral lumbar interbody graft insertion with posterior instrumentation is traditionally performed in two stages requiring repositioning. We describe a novel technique to complete the circumferential procedure simultaneously without patient repositioning. Twenty patients diagnosed with worsening back pain with/without radiculopathy who failed exhaustive conservative management were retrospectively reviewed. Ten patients with both procedures simultaneously from a single lateral approach and 10 control patients with lateral lumbar interbody fusion followed by repositioning and posterior percutaneous instrumentation were analyzed. Pars fractures, mobile grade 2 spondylolisthesis, and severe one-level degenerative disk disease were matched between the two groups. In the simultaneous group, avoiding repositioning leads to lower mean operative times: 130 minutes (versus control 190 minutes; p = 0.009) and lower intraoperative blood loss: 108 mL (versus 93 mL; NS). Nonrepositioned patients were hospitalized for an average of 4.1 days (versus 3.8 days; NS). There was one complication in the control group requiring screw revision. Lateral interbody fusion and percutaneous posterior instrumentation are both readily accomplished in a single lateral decubitus position. In select patients with adequately sized pedicles, performing simultaneous procedures decreases operative time over sequential repositioning. Patient outcomes were excellent in the simultaneous group and comparable to procedures done sequentially.

The role of sacral slope in lumbosacral fusion: a biomechanical study.

OBJECT: Abnormal sacral slope (SS) has shown to increase progression of spondylolisthesis, yet there exists a paucity in biomechanical studies investigating its role in the correction of adult spinal deformity, its influence on lumbosacral shear, and its impact on the instrumentation selection process. This in vitro study investigates the effect of SS on 3 anterior lumbar interbody fusion constructs in a biomechanics laboratory. METHODS: Nine healthy, fresh-frozen, intact human lumbosacral vertebral segments were tested by applying a 550-N axial load to specimens with an initial SS of 20° on an MTS Bionix test system. Testing was repeated as SS was increased to 50°, in 10° increments, through an angulated testing fixture. Specimens were instrumented using a standalone integrated spacer with self-contained screws (SA), an interbody spacer with posterior pedicle screws (PPS), and an interbody spacer with anterior tension band plate (ATB) in a randomized order. Stiffness was calculated from the linear portion of the load-deformation curve. Ultimate strength was also recorded on the final construct of all specimens (n = 3 per construct) with SS of 40°. RESULTS: Axial stiffness (N/mm) of the L5-S1 motion segment was measured at various angles of SS: for SA 292.9 ± 142.8 (20°), 277.2 ± 113.7 (30°), 237.0 ± 108.7 (40°), 170.3 ± 74.1 (50°); for PPS 371.2 ± 237.5 (20°), 319.8 ± 167.2 (30°), 280.4 ± 151.7 (40°), 233.0 ± 117.6 (50°); and for ATB 323.9 ± 210.4 (20°), 307.8 ± 125.4 (30°), 249.4 ± 126.7 (40°), 217.7 ± 99.4 (50°). Axial compression across the disc space decreased with increasing SS, indicating that SS beyond 40° threshold shifted L5-S1 motion into pure shear, instead of compression-shear, defining a threshold. Trends in ultimate load and displacement differed from linear stiffness with SA > PPS > ATB. CONCLUSIONS: At larger SSs, bilateral pedicle screw constructs with spacers were the most stable; however, none of the constructs were significantly stiffer than intact segments. For load to failure, the integrated spacer performed the best; this may be due to angulations of integrated plate screws. Increasing SS significantly reduced stiffness, which indicates that surgeons need to consider using more aggressive fixation techniques.

Economics of image guidance and navigation in spine surgery.

BACKGROUND: Image-guidance and navigation in spinal surgery is becoming more widely utilized. Several studies have shown the use of this technology to increase accuracy of pedicle screw placement, decrease the rates of revision surgery, and minimize radiation exposure. In this paper, the authors analyze the economics of image-guided surgery (IGS) and navigation in spine surgery. METHODS: A literature review was performed using PubMed, the CEA Registry, and the National Health Service Economic Evaluation Database. Each article was screened for inclusion and exclusion criteria, including costs, reoperation, readmission rates, operating room time, and length of stay. RESULTS: Thirteen studies were included in the analysis. Six studies were identified to meet the inclusion criteria for reporting costs and seven met the criteria for analysis of efficacy. Average costs ranged from $17,650 to $39,643. Pedicle screw misplacement rates using IGS ranged from 1.20% to 15.07% while reoperation rates ranged from 0% to 7.42%. CONCLUSION: There is currently an insufficient amount of studies reporting on the economics of spinal navigation to accurately conclude on its cost-effectiveness in clinical practice. Although a few of these studies showed less costs associated with intraoperative imaging, none were able to establish a statistically significant difference. Preliminary findings drawn from this study indicate a possible cost-effectiveness advantage with IGS, but more comprehensive data on costs need to be reported in order to validate its utilization.

Cost-effectiveness analysis in minimally invasive spine surgery.

OBJECT: Medical care has been evolving with the increased influence of a value-based health care system. As a result, more emphasis is being placed on ensuring cost-effectiveness and utility in the services provided to patients. This study looks at this development in respect to minimally invasive spine surgery (MISS) costs. METHODS: A literature review using PubMed, the Cost-Effectiveness Analysis (CEA) Registry, and the National Health Service Economic Evaluation Database (NHS EED) was performed. Papers were included in the study if they reported costs associated with minimally invasive spine surgery (MISS). If there was no mention of cost, CEA, cost-utility analysis (CUA), quality-adjusted life year (QALY), quality, or outcomes mentioned, then the article was excluded. RESULTS: Fourteen studies reporting costs associated with MISS in 12,425 patients (3675 undergoing minimally invasive procedures and 8750 undergoing open procedures) were identified through PubMed, the CEA Registry, and NHS EED. The percent cost difference between minimally invasive and open approaches ranged from 2.54% to 33.68%-all indicating cost saving with a minimally invasive surgical approach. Average length of stay (LOS) for minimally invasive surgery ranged from 0.93 days to 5.1 days compared with 1.53 days to 12 days for an open approach. All studies reporting EBL reported lower volume loss in an MISS approach (range 10-392.5 ml) than in an open approach (range 55-535.5 ml). CONCLUSIONS: There are currently an insufficient number of studies published reporting the costs of MISS. Of the studies published, none have followed a standardized method of reporting and analyzing cost data. Preliminary findings analyzing the 14 studies showed both cost saving and better outcomes in MISS compared with an open approach. However, more Level I CEA/CUA studies including cost/QALY evaluations with specifics of the techniques utilized need to be reported in a standardized manner to make more accurate conclusions on the cost effectiveness of minimally invasive spine surgery.