Outpatient Versus Inpatient Anterior Lumbar Spine Surgery: A Multisite, Comparative Analysis of Patient Safety Measures.

BACKGROUND: The frequency and complexity of spinal surgery performed in an ambulatory surgery center (ASC) is increasing. However, safety and efficacy data of most spinal procedures adapted to the ASC are sparse and have focused on anterior cervical surgery. The purpose of this study was to compare the 90-day complication and readmission rates of anterior lumbar spine surgery performed in an ASC or inpatient setting. METHODS: We performed a retrospective comparative analysis of 226 consecutive anterior lumbar surgeries (283 levels treated) completed in an ASC (n = 124) or in an inpatient tertiary care hospital (n = 102) over a 3-year period. These included anterior lumbar interbody fusion (ALIF), artificial disc replacement (ADR), and hybrids. Patients undergoing simultaneous or staged posterior procedures within 3 months were excluded. Patient demographics and surgical parameters between the two surgical settings were compared. Ninety-day medical complications and readmission rates were assessed. One-way analysis of variance and Chi-square analysis were used. A P value of less than .05 was considered statistically significant. RESULTS: The two study groups had similar baseline characteristics. While there was a trend toward fewer complications, reoperations, and readmissions for the ASC cohort, the differences were not statistically significant. There were 7 intraoperative complications (5.6% minor vascular injury) in the inpatient cohort and 0 in the ASC cohort. The overall 90-day postoperative complication rate was 5.6% for the inpatient cohort and 0.9% for the ASC cohort. The 90-day readmission rate was 1.9% in the ASC cohort and 1.6% in the inpatient cohort. The 90-day reoperation rate was 0.8% for the inpatient cohort and 0% in the ASC cohort. The average hospital stay was 2.3 ± 1.5 days for the inpatient cohort. CONCLUSION: The 90-day readmission rates were lower for outpatients than for inpatients, while the complication and reoperation rates were similar. Our results demonstrate that anterior lumbar procedures, including single-level and multilevel ALIF, ADR, and hybrid procedures, can be performed safely in an ASC. This has significant cost savings implications for the ASC setting.

Adjacent Segment Disease in the Cervical and Lumbar Spine.

Adjacent segment disease (ASD) is disappointing long-term outcome for both the patient and clinician. In contrast to adjacent segment degeneration, which is a common radiographic finding, ASD is less common. The incidence of ASD in both the cervical and lumbar spine is between 2% and 4% per year, and ASD is a significant contributor to reoperation rates after spinal arthrodesis. The etiology of ASD is multifactorial, stemming from existing spondylosis at adjacent levels, predisposed risk to degenerative changes, and altered biomechanical forces near a previous fusion site. Numerous studies have sought to identify both patient and surgical risk factors for ASD, but a consistent, sole predictor has yet to be found. Spinal arthroplasty techniques seek to preserve physiological biomechanics, thereby minimizing the risk of ASD, and long-term clinical outcome studies will help quantify its efficacy. Treatment strategies for ASD are initially nonoperative, provided a progressive neurological deficit is not present. The spine surgeon is afforded many surgical strategies once operative treatment is elected. The goal of this manuscript is to consider the etiologies of ASD, review its manifestations, and offer an approach to treatment.

Predictors of 30- and 90-Day Survival Following Surgical Intervention for Spinal Metastases: A Prognostic Study Conducted at Four Academic Centers.

STUDY DESIGN: A retrospective review. OBJECTIVE: We sought to use data from 4 tertiary medical centers to explore surgical, medical, and demographic factors that influence survival within the first 90 days following surgery for spinal metastases. SUMMARY OF BACKGROUND DATA: Over the last 2 decades, patients with spinal metastases have become more likely to receive surgical intervention. The impact of surgical intervention and its potential benefits must be weighed against the risk of complications and peri-operative mortality. Risk factors that elevate the risk of mortality in the acute postoperative period are not well understood. METHODS: All records of patients who underwent surgery for metastatic spinal disease at 1 of 4 academic medical centers in New England from 2007 to 2013 were obtained. Patient demographics, tumor characteristics, medical comorbidities, nutritional and functional status, as well as surgical variables were abstracted. Mortality was assessed for patients at 30 and 90 days following the procedure. Factors predictive of survival were assessed using bivariate logistic regression. Those factors with P values < 0.20 in the bivariate assessment were included in a final multivariable model that adjusted for confounders. RESULTS: Between 2007 and 2013, 318 patients received surgical intervention for metastatic disease involving the spine. Cancer type did not influence the odds of survival at 30 days, while nutritional status and ambulatory capacity increased survival. Lung cancer significantly decreased the odds of survival at 90 days following surgery (odds ratio 0.36; 95% confidence interval 0.18-0.72), while ambulatory function and nutritional status remained significantly associated with improved survival. CONCLUSION: This effort is one of the first to identify predictors of acute postoperative survival in a large series of patients treated for spinal metastases. Improved nutritional status and ambulatory function may enhance postoperative survival among individuals who undergo surgical intervention for spinal metastases. LEVEL OF EVIDENCE: 3.

Pediatric Intra-Articular Localized Tenosynovial Giant Cell Tumor Presenting as an Acutely Irritable Hip: A Case Report.

CASE: An otherwise healthy 9-year-old girl developed a fever and atraumatic right hip pain with inability to bear weight and exquisite pain with any motion. Her peripheral white blood-cell count was 9.85 × 10/µL, erythrocyte sedimentation rate was 18 mm/hr, and C-reactive protein level was 7.56 mg/L. Aspiration yielded bloody fluid with 611,932 red blood cells/µL, 49,529 white blood cells/µL (92% neutrophils), negative Gram stain, and no crystals. Magnetic resonance imaging revealed an intracapsular lesion anterior to the femoral neck. The joint was irrigated and the lesion was excised. Microscopic examination showed neutrophils interspersed within an otherwise histologically classic tenosynovial giant cell tumor. CONCLUSION: Tenosynovial giant cell tumor may rarely present as an acutely irritable hip.

Modeling 1-year survival after surgery on the metastatic spine.

BACKGROUND CONTEXT: Choosing appropriate surgical patients in the setting of spinal metastases can be challenging. Existing scoring systems focus primarily on patient selection or operative techniques. These scores are limited in their capacity to predict postoperative survival. PURPOSE: The aim was to model survival after spine surgery for metastastic disease. STUDY DESIGN: This was a retrospective multicenter study. PATIENT SAMPLE: All patients who had undergone surgery for the treatment of metastatic spinal disease at one of four tertiary care centers between 2007 and 2013 were included. OUTCOME MEASURE: The outcome measure was 1-year survival after surgery. METHODS: Demographic, medical, oncologic, surgical, and survival data were abstracted from medical records. The effect of predictor variables on survival was evaluated alone and in combination using stepwise logistic regression. Multivariable logistic regression was subsequently used to adjust for confounders. A predictive score was then developed and compared against that of the modified Bauer score alone in terms of prognosticating 1-year survival after surgery. RESULTS: In the time period under investigation, 318 patients underwent surgical intervention for metastastic disease involving the spine, with 307 having data available for analysis. The survival rate at 1 year was 48% (n=142), with a median survival of 10 months. In final adjusted analysis, preoperative modified Bauer score (odds ratio [OR] 3.00; 95% confidence interval [CI] 1.80-5.01; p<.001), ambulatory status (OR 2.47; 95% CI 1.48-4.14; p=.001), and serum albumin (OR 2.80; 95% CI 1.66-4.72; p<.001) were all independent predictors of 1-year survival. The most parsimonious model weighted the modified Bauer score with 2 points and intact ambulatory status and normal serum albumin level with 1 point each, with a ceiling score of 3. The final model using the predictive score was able to explain 74% of the variation in 1-year survival. In contrast, the modified Bauer score alone was only able to explain 64% of the variation in 1-year survival. CONCLUSIONS: This study demonstrates the importance of including factors related to the overall health of a patient, in addition to parameters surrounding their cancer diagnosis, to better prognosticate survival. Our predictive score performed better than the modified Bauer alone and may be used to predict survival after surgical intervention for metastatic disease. LEVEL OF EVIDENCE: III.

Factors Associated With the Failure of Surgical Treatment for Femoroacetabular Impingement: Review of the Literature.

BACKGROUND: With the recent increased recognition of femoroacetabular impingement (FAI) as a cause of hip pain and early osteoarthritis, surgical treatment has proliferated. There is a growing body of literature on outcomes of surgical intervention for FAI, but factors associated with inferior surgical outcomes have not been reviewed systematically. PURPOSE: To review the available literature and identify factors associated with the failure of open or arthroscopic surgery for FAI. STUDY DESIGN: Systematic review. METHODS: Using the PubMed database, we searched for relevant English-language articles published from January 1966 through August 2012. Inclusion criteria were a primary focus on the surgical treatment of FAI, measurement of functional or pain outcomes, identification of treatment failures, and statistical analysis of factors leading to failure. Exclusion criteria were review articles, technique-only articles, and studies of nonoperative management. Two definitions of failure were considered: (1) a lack of statistically significant improvement in validated measures of pain, function, or satisfaction postoperatively; and (2) revision surgery or conversion to hip arthroplasty because of persistent symptoms. The consistency of association between preoperative variables and clinical outcomes was reported across all studies. RESULTS: Thirteen studies were included. Three were retrospective; there were no randomized controlled trials. Many studies had important methodological limitations. Preoperative cartilage damage or osteoarthritis had the strongest and most consistent relationship with conversion to hip arthroplasty and with a lack of improvement in pain or function. Greater age at the index operation, worse preoperative modified Harris Hip Score, and longer duration of symptoms preoperatively (>1.5 years) were associated with conversion to hip arthroplasty. CONCLUSION: Older age, presence of arthritic changes, longer duration of symptoms, and worse preoperative pain and functional scores are associated with poor outcomes of surgery for FAI. Incorporation of these data into discussions with patients may facilitate informed, shared decision making about the surgical treatment of FAI.

Bilateral simultaneous anterior cruciate ligament injury: a case report and national survey of orthopedic surgeon management preference.

Unilateral anterior cruciate ligament (ACL) tear is a common injury seen by sports medicine orthopedic surgeons. However, a bilateral simultaneous ACL injury is extremely rare and has been reported only three times in the literature. We present a young female skier with simultaneous bilateral ACL tears that were managed with staged ACL reconstruction. We then conducted a nationwide survey (United States) to determine the prevalence of simultaneous bilateral ACL tear and preferred management strategies by sports medicine orthopedic surgeons. Sports medicine fellowship directors were contacted and asked to send an 8-item survey to colleagues (sports medicine fellowship trained surgeons) asking about overall number of ACL reconstructions performed, number of bilateral simultaneous ACL injuries seen and optimal management strategies of such an injury. Out of 43 responses, only 22 (51.2%) surgeons had seen a bilateral simultaneous ACL injury. Of these, 16 (76.2%) preferred staged reconstruction. Graft choice was mixed between autograft and allograft, but a large majority preferred either patellar tendon autograft (58%) or hamstring autograft (41%) were the most common choice. Staged reconstruction is the treatment of choice by surgeons surveyed in our study.

Mechanism of disease in early osteoarthritis: application of modern MR imaging techniques -- a technical report.

The application of biomolecular magnetic resonance imaging becomes increasingly important in the context of early cartilage changes in degenerative and inflammatory joint disease before gross morphological changes become apparent. In this limited technical report, we investigate the correlation of MRI T1, T2 and T1ρ relaxation times with quantitative biochemical measurements of proteoglycan and collagen contents of cartilage in close synopsis with histologic morphology. A recently developed MRI sequence, T1ρ, was able to detect early intracartilaginous degeneration quantitatively and also qualitatively by color mapping demonstrating a higher sensitivity than standard T2-weighted sequences. The results correlated highly with reduced proteoglycan content and disrupted collagen architecture as measured by biochemistry and histology. The findings lend support to a clinical implementation that allows rapid visual capturing of pathology on a local, millimeter level. Further information about articular cartilage quality otherwise not detectable in vivo, via normal inspection, is needed for orthopedic treatment decisions in the present and future.

Is an algorithmic approach to the treatment of recurrent dislocation after THA effective?

BACKGROUND: The indications for surgical techniques for treatment of recurrent hip dislocation after THA differ, and their rates of achievement of stability may not be similar. QUESTIONS/PURPOSES: We (1) describe our indications for different approaches for recurrent dislocation, (2) outline an algorithmic approach to the management of recurrently dislocating hips after THA, and (3) determine the overall rate of restoration of stability via this algorithmic approach and for each of four procedures with our indications. PATIENTS AND METHODS: We retrospectively reviewed 66 patients (69 hips) with revision THA for symptomatic recurrent dislocation from 1993 to 2008. We determined the rate of achievement of stability for the overall patient population and with each revision technique. Minimum followup was 2.8 years (mean, 7.8 years; range, 2.8-12.7 years). RESULTS: Fifty-one of the 69 hips (74%) had no further dislocations while nine (13%) required two revisions and nine (13%) required three or more revisions. Ultimately, all of the 69 hips (100%) were stable at followup. Use of a large (36-mm-diameter) head, constrained cup, trochanteric advancement, correction of malposition, and a combination of techniques was effective in achieving stability in 67%, 68%, 86%, 91%, and 90% of cases, respectively. CONCLUSIONS: Separating the treatment of patients based primarily on the presence or absence of (1) component malposition, (2) an intact abductor mechanism, and (3) implants accommodating a large-diameter femoral head, we were able to achieve hip stability with one operation in 74% of cases. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Quantitative MRI using T1ρ and T2 in human osteoarthritic cartilage specimens: correlation with biochemical measurements and histology.

PURPOSE: A direct correlation between T(1ρ), T(2) and quantified proteoglycan and collagen contents in human osteoarthritic cartilage has yet to be documented. We aimed to investigate the orientation effect on T(1ρ) and T(2) values in human osteoarthritic cartilage and to quantify the correlation between T(1ρ), T(2) vs. biochemical composition and histology in human osteoarthritic cartilage. MATERIALS AND METHODS: Thirty-three cartilage specimens were collected from patients who underwent total knee arthroplasty due to severe osteoarthritis and scanned with a 3T MR scanner for T(1ρ) and T(2) quantification. Nine specimens were scanned at three different orientations with respect to the B(0): 0°, 90° and 54.7°. Core punches were taken after MRI. Collagen and proteoglycan contents were quantified using biochemical assays. Histology sections were graded using Mankin scores. The correlation between imaging parameters, biochemical contents and histological scores were studied. RESULTS: Both mean T(1ρ) and T(2) at 54.7° were significantly higher than those measured at 90° and 0°, with T(1ρ) showing less increase compared to T(2). R(1ρ) (1/T(1ρ)) values had a significant but moderate correlation with proteoglycan contents (R=.45, P=.002), while R(2) (1/T(2)) was not correlated with proteoglycan. No significant correlation was found between relaxation times (T(1ρ) or T(2)) and collagen contents. The T(1ρ) values of specimen sections with high Mankin scores were significantly higher than those with low Mankin scores (P<.05). CONCLUSIONS: Quantitative MRI has a great potential to provide noninvasive imaging biomarkers for cartilage degeneration in osteoarthritis.

Assessment of intervertebral disc degeneration with magnetic resonance single-voxel spectroscopy.

This study examined the feasibility of using short-echo water-suppressed point-resolved spectroscopy (PRESS) on a clinical 3T magnetic resonance (MR) scanner for evaluating biochemical changes in degenerated bovine and cadaveric human intervertebral discs. In bovine discs (N = 17), degeneration was induced with papain injections. Degeneration of human cadaveric discs (N = 27) was assessed using the Pfirrmann grading on T(2)-weighted images. Chemicals in the carbohydrate region (Carb), the choline head group (Cho), the N-acetyl region (N-acetyl), and the lipid and lactate region (Lac+Lip) were quantified using (1)H PRESS, and were compared between specimens with different degrees of degeneration. The correlation between the spectroscopic findings and glycosaminoglycan (GAG) quantification using biochemical assays was determined. Significant differences were found between the ratios (N-acetyl/Cho, N-acetyl/Lac+Lip) acquired before and after papain injection in bovine discs. For human cadaveric discs, significant differences in the ratios (N-acetyl/Carb, N-acetyl/Lac+Lip) were found between discs having high and low Pfirrmann scores. Significant correlations were found between N-acetyl/Lac+Lip and GAG content in bovine discs (R = 0.77, P = 0.0007) and cadaveric discs (R = 0.83, P < 0.0001). Significant correlation between N-acetyl/Cho and GAG content was also found in cadaver discs (R = 0.64, P = 0.0039). This study demonstrates for the first time that short-echo PRESS on a clinical 3T MR scanner can be used to noninvasively and can reproducibly quantify metabolic changes associated with degeneration of intervertebral discs.

Magnetic resonance T(1 rho) imaging of osteoarthritis: a rabbit ACL transection model.

OBJECTIVE: The objective of this study was to develop quantitative T(1 rho)-weighted magnetic resonance imaging methodology for the detection and characterization of cartilage degeneration in a rabbit anterior cruciate ligament (ACL) transection model. METHODS: The right knee ACLs of 18 adult female New Zealand white rabbits were transected. The left knee joint served as a sham control. The rabbits were euthanized at 3 (Group 1), 6 (Group 2) and 12 (Group 3) weeks postoperatively. High-resolution 3D fat-saturated spoiled gradient echo images and T(1 rho)-weighted images were obtained in both the sagittal and axial planes at 3 T using a quadrature wrist coil. Following MR analysis, histological slides from the lateral femoral condyle cartilage were graded using the Mankin grading system. RESULTS: For all three groups, the average overall T(1 rho) values were significantly higher in the ACL-transected knee compared to control knee, and the percentage differences in T(1 rho) values between ACL-transected and control increased with the duration of time after transection. The average Mankin score for ACL-transected knees was higher than that for control for each time point, but this difference was statistically significant only for all groups combined. CONCLUSIONS: This study demonstrates the feasibility of using T(1 rho)-weighted imaging as a useful tool in the detection and quantification of cartilage damage in all knee compartments in an ACL-transected rabbit model of cartilage degeneration.

Diagnostic performance of in vivo 3-T MRI for articular cartilage abnormalities in human osteoarthritic knees using histology as standard of reference.

The purpose of this study was (1) to evaluate the sensitivity, specificity and accuracy of sagittal in vivo 3-T intermediate-weighted fast spin-echo (iwFSE) sequences in the assessment of knee cartilage pathologies using histology as the reference standard in patients undergoing total knee replacement, and (2) to correlate MR imaging findings typically associated with osteoarthritis such as bone marrow edema pattern (BMEP) and cartilage swelling with histological findings. Tibial plateaus and femoral condyles of eight knees of seven patients were resected during surgery, and sagittal histological sections were prepared for histology. Preoperative MRI findings were compared to the corresponding region in histological sections for thickness, surface integrity and signal pattern of cartilage, and histological findings in areas of BMEP and swelling were documented. The overall sensitivity, specificity and accuracy were 72%, 69% and 70% for thickness, 69%, 74% and 73% for surface and 36%, 62% and 45% for intracartilaginous signal pattern. For all cases of BMEP on MRI subchondral ingrowth of fibrovascular tissue and increased bone remodeling were observed. MRI using fat-saturated iwFSE sequences showed good performance in assessing cartilage thickness and surface lesions, while signal changes of cartilage were not suited to characterize the severity of cartilage degeneration as validated by histology.

Long-term cyclical in vivo loading increases cartilage proteoglycan content in a spatially specific manner: an infrared microspectroscopic imaging and polarized light microscopy study.

Understanding the changes in collagen and proteoglycan content of cartilage due to physical forces is necessary for progress in treating joint disorders, including those due to overuse. Physical forces in the chondrocyte environment can affect the cellular processes involved in the biosynthesis of extracellular matrix. In turn, the biomechanical properties of cartilage depend on its collagen and proteoglycan content. To understand changes due to physical forces, this study examined the effect of 80 cumulative hours of in vivo cyclical joint loading on the cartilage content of proteoglycan and collagen in the rabbit metacarpophalangeal joint. The forepaw digits of six anesthetized New Zealand White adult female rabbits were repetitively flexed at 1 Hz with an estimated joint contact pressure of 1 to 2 MPa. Joints were collected from loaded and contralateral control specimens, fixed, decalcified, embedded, and thin-sectioned. Sections were examined under polarized light microscopy to identify and measure superficial and mid zone thicknesses of cartilage. Fourier Transform Infrared microspectroscopy was used to measure proteoglycan and collagen contents in the superficial, mid, and deep zones. Loading led to an increase in proteoglycan in the cartilage of all six rabbits. Specifically, there was a 46% increase in the cartilage deep zone (p = 0.003). The collagen content did not change with loading. Joint loading did not change the superficial and mid zone mean thicknesses. We conclude that long-term (80 cumulative hours) cyclical in vivo joint loading stimulates proteoglycan synthesis. Furthermore, stimulation is localized to cartilage regions of high hydrostatic pressure. These data may be useful in developing interventions to prevent overuse injuries or in developing therapies to improve joint function.