Michael D. Daubs

Adult spinal deformity surgery : Complications and outcomes in patients over age 60

Study Design. A retrospective analysis, including prospectively collected patient outcomes data. Objective. To determine the rate of complications and outcomes in patients ≥60 years of age who underwent major spinal deformity surgery requiring a minimum 5-level arthrodesis procedure. Summary of Background Data. As the population ages, an increasing number of older patients are presenting with spinal deformity disorders that may require major reconstructive procedures. Previous studies have reported complication rates as high as 80% in this age group for 1- and 2-level fusion procedures. The prevalence of complications was found to increase with the greater number of levels fused. Methods. Forty-six patients who were 60 years of age or older underwent a thoracic or lumbar arthrodesis procedure consisting of 5 levels or greater. Diagnosis, comorbidities, operative data, hospital data, major and minor complications, and deaths were recorded. Oswestry Disability Index (ODI) Scores were used to evaluate clinical outcomes. Results. Thirty-eight females and 8 males with a mean age of 67 years (range, 60–85 years) and a mean follow-up of 4.2 years (range, 2–11 years) had complete records. Thirty-six (78%) patients had at least 1 comorbidity. Twenty-nine (63%) patients had at least 1 prior spinal surgery. A mean of 9 levels (range, 5–16 levels) were fused in each patient. The overall complication rate was 37%. The major complication rate was 20%. ODI improved from 49 to 25 for a mean improvement of 24 (49%) (P < 0.0001). Conclusion. The overall complication rate was 37% and the major complication rate was 20%. Increasing age was a significant factor (P < 0.05) in predicting the presence of a complication. Patients older than 69 years had more complications. The presence of a comorbidity had no association with complication rates and neither had an effect on final patient reported outcomes, which showed significant improvement (ODI preoperative, 49; postoperative, 25) (P < 0.0001).

Adjacent segment disease followinglumbar/thoracolumbar fusion with pedicle screw instrumentation: a minimum 5-year follow-up.

Study Design. Retrospective radiographic outcomes analysis. Objective. We had 3 hypotheses: 1) a longer fusion; 2) a more proximal instrumented vertebra, and 3) circumferential fusion versus posterior-only fusion would increase the likelihood of adjacent segment disease (ASD). Summary of Background Data. The literature analyzing risk factors, prevalence, and presentation of patients with ASD is varied and without clear consensus. Methods. A total of 188 patients with minimum 5-year follow-up who had lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative disorders were included. Radiographic ASD was defined by: 1) development of spondylolisthesis >4 mm, 2) segmental kyphosis >10°, 3) complete collapse of disc space, or 4) more than 2 grades worsening of Weiner classification. Clinical ASD was defined as 1) symptomatic spinal stenosis, 2) intractable back pain, or 3) subsequent sagittal or coronal imbalance. Results. Radiographic ASD occurred in 42.6% (80 of 188) of patients. Patients with radiographic ASD had worse Oswestry scores (20.3 vs. 12.5; P = 0.001) at ultimate follow-up than those without ASD. Clinical ASD developed in 30.3% (57 of 188) of patients. Clinical ASD manifested as spinal stenosis (n = 47), instability-type back pain (n = 5), and sagittal or coronal imbalance (n = 5). Age at surgery over 50 years and length of fusion were significant risk factors for the development of ASD in the lumbar spine. Fusion to L1–L3 proximally increased the risk of ASD when compared with L4 and L5. Circumferential fusion versus posterior fusion was not a significant factor in the development of ASD. Conclusion. Patients over the age of 50 were at higher risk of developing clinical ASD than those 50 years old or younger. Length of fusion was a significant risk factor in the development of ASD in the lumbar spine. Fusion up to L1–L3 increased the risk of ASD when compared with L4 and L5. Circumferential fusion, as opposed to posterolateral fusion, was not a statistically significant risk factor for the development of ASD.

Proximal junctional kyphosis and failure after spinal deformity surgery: A systematic review of the literature as a background to classification development

Study Design. Systematic review of literature. Objective. To perform a comprehensive English language systematic literature review of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), concentrating on incidence, risk factors, health related quality of life impact, prevention strategy, and classification systems. Summary of Background Data. PJK and PJF are well described clinical pathologies and are a frequent cause of revision surgery. The development of a PJK classification that correlates with clinical outcomes and guides treatment decisions and possible prevention strategies would be of significant benefit to patients and surgeons. Methods. The phrases “proximal junctional,” “proximal junctional kyphosis,” and “proximal junctional failure” were used as search terms in PubMed for all years up to 2014 to identify all articles that included at least one of these terms. Results. Fifty-three articles were identified overall. Eighteen articles assessed for risk factors. Eight studies specifically reviewed prevention strategies. There were no randomized prospective studies. There were 3 published studies that have attempted to classify PJK. The reported incidence of PJK ranged widely, from 5% to 46% in patients undergoing spinal instrumentation and fusion for adult spinal deformity. It is reported that 66% of PJK occurs within 3 months and 80% within 18 months after surgery. The reported revision rates due to PJK range from 13% to 55%. Modifiable and nonmodifiable risk factors for PJK have been characterized. Conclusion. PJK and PJF affect many patients after long segment instrumentation after the correction of adult spinal deformity. The epidemiology and risk factors for the disease are well defined. A PJK and PJF scoring system may help describe the severity of disease and guide the need for revision surgery. The development and prospective validation of a PJK classification system is important considering the prevalence of the problem and its clinical and economic impact. Level of Evidence: N/A

Spinopelvic parameters in postfusion flatback deformity patients

BACKGROUND CONTEXT Fixed sagittal imbalance (FSI) may result from loss of adequate lumbar lordosis (LL) after spinal fusion. Pelvic incidence (PI) is a fixed anatomical parameter that determines LL and overall spinal sagittal alignment. PURPOSE We describe the spinopelvic parameters in a series of patients with postfusion FSI. We hypothesize that patients who develop postfusion FSI may have a high PI and are thus more at risk from a loss of adequate LL. STUDY DESIGN Retrospective chart and image review. PATIENT SAMPLE Consecutive patients with degenerative spine disease with clinically significant postoperative FSI after fusion. METHODS/OUTCOME MEASURES: We evaluated 36-in full spine films for PI, LL, pelvic tilt (PT), thoracic kyphosis (TK), and C7 plumb line. RESULTS Fifteen patients with clinically significant FSI were identified: 13 women and 2 men (mean age, 63.3 years). They had undergone a mean of 2.9 prior spine surgeries. The mean PI was elevated at 66.7 degrees (normal 48-55 degrees ), mean PT was elevated at 35.5 degrees (normal 12-18 degrees ), mean LL was reduced at 11.8 degrees (normal 43-61 degrees ), mean TK was reduced at 19.3 degrees (normal 41-48 degrees ), and mean C7 plumb line was elevated at 13.1cm (normal <3cm). CONCLUSIONS In the current series, patients with FSI after spinal fusion had an elevated PI and inadequate LL. They attempted to compensate for FSI with reduced TK and with increased pelvic retroversion (PT). Overall, it is important to identify sagittal spinopelvic parameters and promote sagittal balance when performing lumbar fusions.

Early failures following cervical corpectomy reconstruction with titanium mesh cages and anterior plating

Study Design. Retrospective case series. Objective. To evaluate the use of titanium mesh cages in the reconstruction of the cervical spine following corpectomy. Summary of Background Data. Previous studies have shown high successful fusion rates and low failure rates with this technique. Similar reconstruction techniques using anterior strut bone grafting and anterior plating have shown higher failure rates following multilevel corpectomies. Methods. A retrospective review was performed of 23 consecutive patients who underwent anterior cervical corpectomy reconstructed with a titanium mesh cage, local autograft, and fixed anterior plating. Medical records and radiographs were reviewed. Average follow-up was 28 months. Results. Seven patients (30%) had reconstruction failures. There was 1 failure (6%) in the 1-level corpectomy group and 6 (75%) in the multilevel corpectomy group. All failures occurred before 12 weeks after surgery. The remaining patients had successful fusion (70%). Conclusion. There is a high early failure rate (75%) with the use of a titanium mesh cage and fixed anterior plating for reconstruction of multilevel corpectomies. Posterior fusion and instrumentation should be considered when using this technique for multilevel reconstructions.

Thoracolumbar spine trauma classification: the Thoracolumbar Injury Classification and Severity Score system and case examples

OBJECT The aim of this study was to review the Thoracolumbar Injury Classification and Severity Score (TLICS) and to demonstrate its application through a series of spine trauma cases. METHODS The Spine Trauma Study Group collaborated to create and report the TLICS system. The TLICS system is reviewed and applied to 3 cases of thoracolumbar spine trauma. RESULTS The TLICS system identifies 3 major injury characteristics to describe thoracolumbar spine injuries: injury morphology, posterior ligamentous complex integrity, and neurological status. In addition, minor injury characteristics such as injury level, confounding variables (such as ankylosing spondylitis), multiple injuries, and chest wall injuries are also identified. Each major characteristic is assigned a numerical score, weighted by severity of injury, which is then summated to yield the injury severity score. The TLICS system has demonstrated initial success and its use is increasing. Limitations of the TLICS system exist and, in some instances, have yet to be addressed. Despite these limitations, the severity score may provide a basis to judge spinal stability and the need for surgical intervention. CONCLUSIONS By addressing both the posterior ligamentous integrity and the patients neurological status, the TLICS system attempts to overcome the limitations of prior thoracolumbar classification systems. The TLICS system has demonstrated both validity and reliability and has also been shown to be readily learned and incorporated into clinical practice.

Loss of spinal cord monitoring signals in children during thoracic kyphosis correction with spinal osteotomy: why does it occur and what should you do?

Study Design. A retrospective review of pediatric kyphosis patients undergoing a spinal cord-level osteotomy for correction. Objective. To evaluate the prevalence, etiology, timing, and intervention related to loss of spinal cord monitoring data during surgical correction of pediatric kyphosis in the spinal cord region. Summary of Background Data. Although much has been written regarding the risks inherent to scoliosis surgery, there is less literature available regarding the neurologic outcomes of pediatric kyphosis surgery. As more surgeons contemplate posterior-only kyphosis correction with spinal cord-level osteotomies, the importance of maintaining spinal cord neurologic function is paramount. Methods. Forty-two patients with pediatric kyphosis undergoing a posterior-only spinal reconstruction with a spinal cord level osteotomy or posterior-based vertebral column resection performed were reviewed. Patients were categorized by diagnosis, type and incidence of osteotomies, and loss of neurogenic mixed-evoked potential (NMEP) data. Interventions required to regain data and postoperative neurologic outcomes were also reviewed. Results. Of the 42 patients, 9 (21.4%) demonstrated a complete loss of NMEP data sometime during surgery while concomitant somatosensory sensory-evoked potentials (SSEP) remained within acceptable limits of baseline values. All 9 patients had intraoperative intervention including: blood pressure elevation (n = 1), release of corrective forces (n = 2), blood pressure elevation and correction release (n = 3), malalignment/subluxation adjustment (n = 1), further bony decompression (n = 1), or restoration of anterior column height via a titanium cage along with further posterior decompression (n = 1). In all cases, SSEPs were unchanged and NMEPs returned varying from 8 to 20 minutes after loss, with all patients having a normal wake-up test intraoperatively and a normal neurologic examination after surgery. Conclusion. Intraoperative multimodality monitoring with some form of motor tract assessment is a fundamental component of kyphosis correction surgery in the spinal cord region in order to create a safer, optimal environment and to minimize neurologic deficit. The surgeon must be able to trust the information monitoring provides and act on it accordingly.

Trends in the surgical treatment of lumbar spine disease in the United States

BACKGROUND CONTEXT There is a lack of agreement among spine surgeons as to the best surgical treatment modality for many degenerative lumbar diseases. Although there are many studies examining trends in spinal surgery, specific studies reporting the variations in surgical treatment in the United States for these diseases are lacking. PURPOSE The aim of this study was to analyze trends in lumbar spinal fusion methods for common lumbar pathologies in the United States. STUDY DESIGN/SETTING National insurance database review: 2004-2009. PATIENT SAMPLE Data is taken from United Healthcare and represents more than 25 million patients. OUTCOME MEASURES No outcomes were measured in this study. METHODS Using a private insurance database, we identified patients who underwent one of five types of instrumented single-level lumbar spinal fusion for the 10 most common primary diagnoses. Surgery rates were reviewed from 2004 to 2009 and were stratified according to patient age, patient gender, and region in the United States. Poisson regression analysis was performed to determine regional and demographic differences in treatment modality. The authors received no funds in support of this work. RESULTS A total of 23,986 patients met our search criteria. Of the five fusion types, posterior lumbar interbody fusion (PLIF) with posterolateral fusion (PLF) was the most common (45%), followed by PLF (19%), anterior lumbar interbody fusion (ALIF, 16%), PLIF (10%), and ALIF with PLF (9%). There was a significant increase in PLIF with PLF (p<.0001), PLIF (p<.0001), PLF (p=.012), ALIF (p<.0001), and ALIF with PLF (p<.0001) from 2004 to 2009. After controlling for gender, there were significant differences between regions for all fusion types (p<.0001). The likelihood of a posterior fusion increased with age. Anterior fusions were more common in the 30- to 49-year-old age range than in patents older than 50. For patients in age groups older than 30, there was an increased number who underwent a circumferential fusion or an ALIF (p<.022). Fusion types were significantly different between genders (p<.026). Both genders had an overall increase in the number of fusions (p<.001) over the time period studied. CONCLUSIONS There are large differences in the United States for surgical treatment methods for lumbar spine pathology. These differences are likely multifactorial, with both patient and surgeon traits playing a role. Illustrating these differences will hopefully lead to outcomes research to determine the indications, efficacy, and appropriateness of these surgical methods, an important step on the path toward standardization of care.

Evidence for an Inherited Predisposition to Lumbar Disc Disease

BACKGROUND A genetic predisposition for the development of symptomatic lumbar disc disease has been suggested by several twin sibling studies and subsequent genetic marker studies. The purpose of the present study was to define population-based familial clustering among individuals with a diagnosis of, or treated for, lumbar disc herniation or disc degeneration. METHODS The Utah Population Database allows analysis of combined health and genealogic data for over one million Utah residents. We used the International Classification of Diseases, Ninth Revision, diagnosis codes entered in patient records to identify patients with a diagnosis of either lumbar disc herniation or lumbar disc degeneration and genealogic data. The hypothesis of excess relatedness (familial clustering) was tested with use of the Genealogical Index of Familiality, which compares the average relatedness of affected individuals with expected population relatedness. Relative risks in relatives were estimated by comparing rates of disease in relatives with expected population rates (estimated from the relatives of matched controls). This methodology has been previously reported for other disease conditions but not for spinal diseases. RESULTS The Genealogical Index of Familiality test for 1264 patients with lumbar disc disease showed a significant excess relatedness (p < 0.001). Relative risk in relatives was significantly elevated in both first-degree (relative risk, 4.15; p < 0.001) and third-degree relatives (relative risk, 1.46; p = 0.027). CONCLUSIONS Excess relatedness of affected individuals and elevated risks to both near and distant relatives was observed, strongly supporting a heritable contribution to the development of symptomatic lumbar disc disease.

Early proximal junctional failure in patients with preoperative sagittal imbalance.

BACKGROUND CONTEXT Proximal junctional failure (PJF) is a recognized complication of spinal deformity surgery. Acute PJF (APJF) has recently been demonstrated to be 5.6% in the adult spinal deformity (ASD) population. The incidence and rate of return to the operating room for APJF have not been specifically investigated in individuals with sagittal imbalance. PURPOSE The purpose of this study was to report the incidence of APJF in patients with preoperative sagittal imbalance and the rate of return to the operating room for APJF. STUDY DESIGN/SETTING This study is based on a retrospective review of prospectively collected database of ASD patients. PATIENT SAMPLE One hundred seventy-three consecutive patients were included with preoperative sagittal imbalance according to one of the following common parameters: sagittal vertical axis (SVA) greater than 50 mm, global sagittal alignment greater than 45°, or pelvic incidence minus lumbar lordosis greater than 10°. OUTCOME MEASURES Outcome measure was presence and/or absence of APJF defined as fracture at the upper instrumented vertebra (UIV) or UIV+1, failure of UIV fixation, 15° or more proximal junctional kyphosis, or need for extension of instrumentation within 6 months of surgery. METHODS We performed radiographic measurements on X-rays at preoperative, immediate postoperative, and 6-month follow-up visits. The APJF rate was reported for the entire patient population with preoperative sagittal imbalance. Acute PJF incidence was calculated postoperatively for each of the accepted sagittal balance parameters and/or formulas. Patients with persistent postoperative sagittal imbalance were compared with the sagittally balanced group. We also assessed for threshold values. RESULTS Acute PJF was observed in 60 of 173 patients (35%) and was least common in fusions with the UIV in the upper thoracic (UT) spine (p=.035). Of those who developed APJF, 21.7% required surgery. Proximal junctional kyphosis 15° or more was the most common form of APJF in fusions to the UT spine but least likely to need revision (p=.014). The most common mode of failure in lower thoracic (LT) or lumbar (L) fusions was UIV fracture. Postoperative SVA less than 50 mm was a significant risk factor for APJF (p=.009). CONCLUSIONS Acute PJF is more common in patients with preoperative sagittal imbalance (35%) than the general adult deformity patient population, and 37% of those with APJF require revision. It is least common when the UIV is in the UT spine, compared with the LT or L spine. Sagittal balance correction to an SVA 50 mm or less was a significant risk factor in patients with preoperative sagittal imbalance.