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.

White Cord Syndrome and Acute Tetraplegia After Posterior Cervical Decompression: A Case Report.

CASE: A 55-year-old man undergoes posterior cervical decompression and instrumentation for progressive cervical myelopathy and develops white cord syndrome (WCS) postoperatively with acute tetraplegia. CONCLUSION: WCS is a rare complication of spinal surgery that is thought to be due to reperfusion injury. We diagnosed WCS in our patient through postoperative examination consisting of acute tetraplegia and magnetic resonance imaging revealing increased signal in the cord. In this case, we used intravenous dexamethasone and mean arterial pressure above 90 mm Hg resulting in markedly improved clinical examination.

Spine Infections Reduced at Dedicated Orthopaedics and Spine Hospital.

BACKGROUND: Previous studies stratified postoperative infection risk by patient comorbidities. However, it is unclear whether the incidence varies by surgical approach in a specialized orthopaedic setting. This study aims to compare infection rates and microbiologic characteristics of postoperative spine infections requiring return to the operating room for debridement by hospital setting: a dedicated orthopaedic and spine hospital versus a general hospital serving multiple surgical specialties. METHODS: The study is a retrospective review of prospectively collected data. Procedures performed between March 2006 and August 2008 at the multispecialty university hospital were compared with cases at an orthopaedic specialty hospital from September 2008 through August 2016. The surgeons, residents, and patients were similar, but the operative venue changed in 2008. RESULTS: The overall general university hospital infection rate was 2.03%, higher than the overall infection rate at the dedicated orthopaedic and spine hospital of 1.31% (P < .0104). The general university infection rate was 2.27% in the final years of practice, compared with 0.91% at the dedicated orthopaedic and spine hospital (P < .0001) during a recent 2-year time frame. Demographic variables did not significantly differ between the 2 settings. The overall proportion of Gram-negative infection rates was not statistically different (21.7% vs 18.6%), despite an increased proportion of Gram-negative infections at the general university hospital following surgery from an anterior approach. Most of the organisms isolated in both facilities were Staphylococcus species. There was no difference in the seasonality of postoperative spine infections in either setting. CONCLUSIONS: In transitioning from a multispecialty university hospital to a dedicated orthopaedic hospital, the incidence of postoperative spine infections was significantly reduced to 0.91%. Despite the change in venue, the proportion of Gram-negative infections (∼20%) following spine surgery did not significantly change. These results suggest improved infection rates during the course of the last 10 years with consistent proportions of Gram-negative infections. LEVEL OF EVIDENCE: 3.

Spontaneous Spinal Epidural Hematoma: An Atypical Clinical Presentation and Discussion of Management.

INTRODUCTION: Spontaneous spinal epidural hematoma (SSEH) is a rare but potentially devastating condition if not appropriately identified and managed. A few case series exist regarding SSEH and certain risk factors have been described; however, much continues to be unknown regarding the pathophysiology and optimal management. CASE PRESENTATION: We present the case of SSEH in a healthy 33-year-old African American woman with no identifiable risk factors who initially presented with significant neurologic compromise. This case reports discusses pertinent clinical presentation, imaging findings, and surgical management. The patient demonstrated near-complete neurologic recovery, highlighting the need for prompt identification and intervention. CONCLUSIONS: We believe this case adds to the limited literature surrounding the topic, particularly in regard to diagnosis and surgical management. It is essential for clinicians to be cognizant of SSEH for timely diagnosis and treatment, even in patients without obvious risk factors.

Anterior Column Realignment (ACR) With and Without Pre-ACR Posterior Release for Fixed Sagittal Deformity.

BACKGROUND: Multiple studies have demonstrated a strong correlation between sagittal malalignment and health-related quality of life measures. Thus, correction of sagittal vertical axis (SVA), pelvic tilt (PT), lumbar lordosis-pelvic incidence (LL-PI), and T1 spinopelvic inclination (T1SPi) have become a primary objective of adult spinal deformity surgery. Anterior column realignment (ACR) has emerged as a less invasive technique and while the addition of posterior osteotomies has shown greater correction in ACR, it is unknown if a pre-ACR posterior release is necessary for optimal correction. The purpose of this study was to determine if pre-ACR posterior release allows for greater sagittal deformity correction. METHODS: Seventeen patients were identified that underwent minimum 1-level ACR. Ten patients underwent an anterior-posterior surgical sequence without a pre-ACR posterior release, and 7 underwent a posterior-anterior-posterior (PAP) sequence with a pre-ACR posterior release. Radiographic outcomes at final follow-up and complications were compared. RESULTS: Both groups saw significant improvements in LL, LL-PI, PT, SVA, and T1SPi but the correction was not significantly different between cohorts. With the exception of PT in the PAP group, the improvements in LL-PI, PT, and SVA correlated to improvement in Scoliosis Research Society-Schwab classification. The correction achieved at the ACR level, represented by motion segment angle, was greater in the PAP group by a degree that approached statistical significance. Five patients (29%) had 6 complications. CONCLUSIONS: Both techniques achieved meaningful improvements in overall sagittal alignment. Our results suggest that a pre-ACR posterior release may allow for greater correction specifically at the ACR level but may not always be necessary to achieve clinically meaningful correction of sagittal plane deformity. LEVEL OF EVIDENCE: 3. CLINICAL RELEVANCE: We present our experience with and without pre-ACR posterior release. To our knowledge, this is the first study to show that pre-ACR posterior release may achieve greater correction at the ACR level.

The 5-Item Modified Frailty Index Is Predictive of 30-Day Postoperative Complications in Patients Undergoing Kyphoplasty Vertebral Augmentation.

BACKGROUND: Vertebral compression fractures are the most common spine injury seen in elderly patients. Vertebral augmentation is considered a safe and effective treatment. The ability to predict outcomes based on comorbidities is lacking. The modified frailty index has been used to predict complications after orthopedic and surgical procedures. We hypothesized that despite a low rate of adverse outcomes, postoperative complications after kyphoplasty would be greater in patients who are frail. METHODS: The National Surgical Quality Improvement Program database was queried for patients who underwent kyphoplasty between 2006 and 2015. Complication data including 30-day complications, life-threatening complications, reoperation and readmission rate, and length of stay data was recorded, and 5-item modified frailty index (5i-mFI) scores were calculated. Univariate and multivariate logistic regression analyses were then conducted to analyze frailty as a predictor of postoperative complications after kyphoplasty. RESULTS: In total, 2465 patients were identified (mean age = 73.98). As 5i-mFI increased from 0 to ≥2, the rate of overall complications increased nearly 3-fold from 3.7% to 10.4% (P < 0.001) and the rate of life-threatening complications increased from 0.8% to 2.4% (P = 0.042). In addition, 30-day readmission increased from 8.9% to 12.9% (P = 0.005), adverse hospital discharge increased from 7.6% to 25.6% (P < 0.001), and length of stay increased from 1.66 days to 3.75 days (P < 0.001). Frailty was associated with increased total complications, Clavien-Dindo IV complications, length of stay, and 30-day readmission rates. CONCLUSIONS: The 5i-mFI is a straightforward assessment tool that correlates with outcomes after kyphoplasty. It can be used to help clinicians predict adverse events and facilitate informed discussions with their patients.

Epidemiology and treatment of central cord syndrome in the United States.

BACKGROUND: The objective of this study is to demonstrate the epidemiology and trends in management of patients with central cord syndrome (CCS) who present to the emergency department. Recent literature has reported that surgical treatment for CCS have increased over the previous decades. METHODS: The National Emergency Department Sample (NEDS) was queried from 2009 through 2012 to generate national estimates of patients who presented to the emergency department in the United States and were diagnosed with CCS. RESULTS: From 2009 through 2012, there were 11,975 emergency room visits for CCS (mean age 60 years). The two most common injury mechanisms were: fall (55%) and motor vehicle accident (15%). Concomitant cervical fractures were found in 10% patients. Ninety-three percent of patients were admitted to the hospital directly or after transfer to another facility, and 7% were discharged home. Fifty-five percent of patients were treated non-operatively, 39% were treated with cervical fusion surgery and 6% were treated with laminoplasty. Of patients who underwent cervical fusion, 62% received anterior decompression and fusion, 32% received posterior decompression and fusion, and 6% received combined anterior-posterior decompression and fusion. The incidence of in-hospital mortality was 2.6%. Mortality was associated with older patient age (OR 1.06, P<0.001) and greater comorbidities (OR 1.72, P<0.001). CONCLUSIONS: Majority of patients who presented to the emergency room for CCS in the United States were treated non-operatively. Advanced age and greater comorbidities were the factors that were most associated with increased risk of in-hospital mortality in patients with CCS.

Effect of perioperative steroids on dysphagia after anterior cervical spine surgery: A systematic review.

BACKGROUND: Dysphagia following anterior cervical spine surgery is common. Steroids potentially reduce post-operative inflammation that leads to dysphagia; however, the efficacy, optimal dose and route of steroid administration have not been fully elucidated. OBJECTIVE: The purpose of this systematic review is to evaluate the effect of peri-operative steroids on the incidence and severity of dysphagia following anterior cervical spine surgery. METHODS: A PubMed search adherent to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed to include clinical studies reporting use of steroids in adult patients following anterior cervical spine surgery. Data regarding steroid dose, route and timing of administration were abstracted. Incidence and severity of post-operative dysphagia were pooled across studies. RESULTS: Seven of 72 screened articles met inclusion criteria for a total of 246,298 patients that received steroids. Patients that received systemic and local steroids had significant reductions in rate and severity of dysphagia postoperatively. Reduction of dysphagia severity was more pronounced in patients undergoing multilevel procedures in both groups. There was no difference in infectious complications among patients that received steroids compared with controls. There was no difference in fusion rates at long-term follow-up. CONCLUSIONS AND CLINICAL RELEVANCE: Steroids may reduce dysphagia after anterior cervical spinal procedures in the early post-operative period without increasing complications. This may be especially beneficial in patients undergoing multilevel procedures. Future studies should further define the optimal dose and route of steroid administration, and the specific contraindications for use.

Laminoplasty versus laminectomy with fusion for the treatment of spondylotic cervical myelopathy: short-term follow-up.

BACKGROUND CONTEXT: Laminoplasty and laminectomy with fusion are two common procedures for the treatment of cervical spondylotic myelopathy. Controversy remains regarding the superior surgical treatment. PURPOSE: To compare short-term follow-up of laminoplasty to laminectomy with fusion for the treatment of cervical spondylotic myelopathy. STUDY DESIGN/SETTING: Retrospective review comparing all patients undergoing surgical treatment for cervical spondylotic myelopathy by a single surgeon. PATIENT SAMPLE: All patients undergoing laminoplasty or laminectomy with fusion by a single surgeon over a 5-year period (2007-2011). OUTCOME MEASURES: Cervical alignment and range of motion on pre- and post-operative radiographs and clinical outcome measures including Japanese Orthopaedic Association (JOA) scores, neck disability index (NDI), short form-12 mental (SF-12M) and physical (SF-12P) composite scores and visual analog pain scores for neck (VAS-N) and arm (VAS-A). METHODS: Patients undergoing laminoplasty or laminectomy with fusion by a single surgeon were reviewed. Cohorts of 41 laminoplasty patients and 31 laminectomy with fusion patients were selected based on strict criteria. The cohorts were well matched based on pre-operative clinical scores, radiographic measurements, and demographics. The average follow-up was 19.2 months for laminoplasty and 18.2 months for laminectomy with fusion. Evaluated outcomes included Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), short form-12 (SF-12), visual analog pain scores (VAS), cervical sagittal alignment, cervical range of motion, length of stay, cost and complications. RESULTS: The improvement in JOA, SF-12 and VAS scores was similar in the two cohorts after surgery. There was no significant change in cervical sagittal alignment in either cohort. Range-of-motion decreased in both cohorts, but to a greater degree after laminectomy with fusion. C5 nerve root palsy and infection were the most common complications in both cohorts. Laminectomy with fusion was associated with a higher rate of C5 nerve root palsy and overall complications. The average hospital length of stay and cost were significantly less with laminoplasty. CONCLUSIONS: This study provides evidence that laminoplasty may be superior to laminectomy with fusion in preserving cervical range of motion, reducing hospital stay and minimizing cost. However, the significance of these differences remains unclear, as laminoplasty clinical outcome scores were generally comparable to laminectomy with fusion.

Where should a laminoplasty start? The effect of the proximal level on post-laminoplasty loss of lordosis.

BACKGROUND CONTEXT: Open-door laminoplasty is a useful operation in the surgical management of cervical myelopathy with favorable outcomes and relatively low complications. One potential undesirable outcome is a decrease in cervical lordosis postoperatively. It is unknown whether the most proximal level undergoing laminoplasty affects the magnitude of loss of lordosis. PURPOSE: This study aimed to compare the loss of cervical lordosis postoperatively in patients for whom the most proximal level undergoing laminoplasty is C3 versus C4. STUDY DESIGN/SETTING: A retrospective radiographic review at an academic center was carried out. PATIENT SAMPLE: A total of 65 patients at a single institution who underwent plated open door laminoplasty for cervical myelopathy by multiple surgeons over a 5-year period were included. OUTCOME MEASURES: The primary outcome was change in cervical lordosis, which was the difference in C2-T1 Cobb angle between the postoperative and preoperative films. METHODS: Patients were divided into two groups based on the most proximal vertebral level undergoing laminoplasty. There were 49 patients who underwent laminoplasty beginning at C3, whereas 16 patients underwent laminoplasty beginning at C4. The C2-T1 Cobb angle was measured on the preoperative film and on the final postoperative follow-up film. The difference between these values was calculated for each patient, and the mean of the differences for the C3 group was compared with that of the C4 group. RESULTS: When C3 was the proximal plated laminoplasty level, loss of lordosis averaged 9°. In contrast, when C4 was the proximal plated level, loss of lordosis was significantly less and averaged only 3° (p=.047). In the group as a whole, mean preoperative lordosis was 18° compared with 11° postoperatively, for an overall 7° loss of lordosis. CONCLUSIONS: Starting the laminoplasty at C4 led to significantly less loss of lordosis than starting at C3. When the pattern of spinal cord compression does not require laminoplasty at C3, consideration should be given to making C4 the most cephalad laminoplasty level rather than C3 to better preserve lordosis.

N-Cadherin-Mediated Signaling Regulates Cell Phenotype for Nucleus Pulposus Cells of the Intervertebral Disc.

Juvenile nucleus pulposus (NP) cells of the intervertebral disc (IVD) are large, vacuolated cells that form cell clusters with strong cell-cell interactions. With maturation and aging, NP cells lose their ability to form these cell clusters, with aging-associated changes in NP cell phenotype, morphology, and proteoglycan synthesis that may contribute to IVD degeneration. Therefore, it is important to understand the mechanisms governing juvenile NP cell cluster behavior towards the goal of revealing factors that can promote juvenile, healthy NP cell phenotypes. N-cadherin has been identified as a cell-cell adhesion marker that is present in juvenile NP cells, but disappears with age. The goal of this study was to reveal the importance of N-cadherin in regulating cell-cell interactions in juvenile NP cell cluster formation and test for a regulatory role in maintaining a juvenile NP phenotype in vitro. Juvenile porcine IVD cells, of notochordal origin, were promoted to form cell clusters in vitro, and analyzed for preservation of the juvenile NP phenotype. Additionally, cadherin-blocking experiments were performed to prevent cluster formation in order to study the importance of cluster formation in NP cell signaling. Findings reveal N-cadherin-mediated cell-cell contacts promote cell clustering behavior and regulate NP cell matrix production and preservation of NP-specific markers. Inhibition of N-cadherin-mediated contacts resulted in loss of all features of the juvenile NP cell. These results establish a regulatory role for N-cadherin in juvenile NP cells, and suggest that preservation of the N-cadherin mediated cell-cell contact is important for preserving juvenile NP cell phenotype and morphology.

Extreme lateral interbody fusion for the treatment of adult degenerative scoliosis.

Extreme lateral interbody fusion (XLIF; NuVasive Inc., San Diego, CA, USA) is a minimally invasive lateral transpsoas approach to the thoracolumbar spine. Though the procedure is rapidly increasing in popularity, limited data is available regarding its use in deformity surgery. We aimed to evaluate radiographic correction using XLIF in adults with degenerative lumbar scoliosis. Thirty consecutive patients were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Plain radiographs were obtained on all patients preoperatively, postoperatively, and at most recent follow-up. Plain radiographic measurements of coronal Cobb angle, apical vertebral translation, segmental lordosis, global lordosis, disc height, neuroforaminal height and neuroforaminal width were made at each time point. CT scans were obtained for all patients 1 year after surgery to evaluate for fusion. There was significant improvement in multiple radiographic parameters from preoperative to postoperative. Cobb angle corrected 72.3%, apical vertebral translation corrected 59.7%, neuroforaminal height increased 80.3%, neuroforaminal width increased 7.4%, and disc height increased 116.7%. Segmental lordosis at L4-L5 increased 14.1% and global lordosis increased 11.5%. There was no significant loss of correction from postoperative to most recent follow-up. There was an 11.8% pseudoarthrosis rate at levels treated with XLIF. Complications included lateral incisional hernia (n=1), rupture of anterior longitudinal ligament (n=2), wound breakdown (n=2), cardiac instability (n=1), pedicle fracture (n=1), and nonunion requiring revision (n=1). XLIF significantly improves coronal plane deformity in patients with adult degenerative scoliosis. XLIF has the ability to correct sagittal plane deformity, although it is most effective at lower lumbar levels.

Lumbar facet cyst resolution following anterior interbody fusion.

Facet cysts are a relatively common source of neural compression in the lumbar spine. Open decompression and fusion are frequently used to treat the stenosis and instability associated with this pathology. Recently, anterior lumbar interbody fusion (ALIF) has increased in popularity for the treatment of lumbar degenerative conditions. ALIF may achieve indirect decompression of the neural elements with less surgical morbidity than conventional open approaches. To date, there are no published reports describing the use of indirect decompression or interbody fusion for the treatment of facet cysts. We report a patient who developed an L4-L5 facet cyst secondary to degenerative changes and spondylolisthesis. ALIF with posterior instrumentation was used to address his condition. Six months after surgery, the patient had complete resolution of his symptoms. MRI revealed complete resolution of the facet cyst. This patient provides previously unreported evidence that interbody fusion alone may result in facet cyst resolution. Clinical studies are needed to evaluate if interbody fusion can consistently relieve the symptoms associated with facet cysts without the use of direct decompression.

Distant Harrington rod migration 35 years after implantation.

Harrington rods have been successfully implanted in thousands of patients for the correction of scoliotic deformity since the 1950s. An exceedingly rare complication of Harrington rod placement is loosening with resultant migration. The authors present a 50-year-old woman who had a single Harrington rod placed when she was 15 years old. Thirty-five years later, she presented with acute sensory changes in her lower extremities. Imaging revealed rod failure and migration of the hardware distally, resulting in penetration of the wall of the rectum. Due to the unique anatomical position of the migrated hardware, sigmoidoscopy was used to directly visualize and remove the rod. The patient ultimately made a full recovery. Rod migration is an exceedingly rare complication that has been described only a few times since the introduction of Harrington rods over 60 years ago. The case herein is particularly unique given the extensive period of time that passed before migration (35 years) and the use of sigmoidoscopy for hardware removal.

Risk factors for infection after orthopaedic spine surgery at a high-volume institution.

Surgical site infections are associated with increased morbidity, mortality, and resource utilization. To identify risk factors for infection, the authors reviewed all orthopaedic spine operations at Duke University Medical Center from 2005 to 2010. Of the 3138 patients treated during the study period, 115 developed a surgical site infection (3.7%). Demographics, comorbidities, and perioperative blood glucose levels were analyzed in the infected and uninfected cohorts. History of myocardial infarction, congestive heart failure, renal disease, pneumonia, urinary tract infection, and diabetes mellitus (DM) were associated with a higher risk of infection. Notably, a diagnosis of DM nearly doubled the risk of infection. Even in patients without DM, perioperative blood glucose levels greater than 140 mg/dL doubled the risk of infection. The authors propose that strict blood glucose control in both DM and non-DM patients may significantly reduce the risk of infection after spinal surgery.

Clinical outcomes of extreme lateral interbody fusion in the treatment of adult degenerative scoliosis.

INTRODUCTION: The use of extreme lateral interbody fusion (XLIF) and other lateral access surgery is rapidly increasing in popularity. However, limited data is available regarding its use in scoliosis surgery. The objective of this study was to evaluate the clinical outcomes of adults with degenerative lumbar scoliosis treated with XLIF. METHODS: Thirty consecutive patients with adult degenerative scoliosis treated by a single surgeon at a major academic institution were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Validated clinical outcome scores were obtained on patients preoperatively and at most recent follow-up. Complications were recorded. RESULTS: The study group demonstrated improvement in multiple clinical outcome scores. Oswestry Disability Index scores improved from 24.8 to 19.0 (P < 0.001). Short Form-12 scores improved, although the change was not significant. Visual analog scores for back pain decreased from 6.8 to 4.6 (P < 0.001) while scores for leg pain decreased from 5.4 to 2.8 (P < 0.001). A total of six minor complications (20%) were recorded, and two patients (6.7%) required additional surgery. CONCLUSIONS: Based on the significant improvement in validated clinical outcome scores, XLIF is effective in the treatment of adult degenerative scoliosis.