The impact of the Florida law HB21 on opioid prescribing patterns after spine surgery.

Background: The opioid epidemic represents a major public health issue in the United States and has led to significant morbidity and mortality. On July 1 2018, Florida implemented state-law House Bill 21 (HB21), limiting opioid prescriptions to a 3-day supply for acute pain or 7 days if an exception is documented. The purpose of this study is to evaluate the effects of HB21 on opioid prescribing patterns after spine surgery. Methods: Patients 18 years and older who underwent spine surgery between January 2017 and January 2021 were eligible for inclusion. Information including demographics, pills, days, and morphine milligram equivalents (MMEs) was obtained via retrospective chart review using the Florida Prescription Drug Monitoring Program and Epic Chart Review. Student's t tests and Fisher's exact tests were used for comparison of continuous variables. Multiple logistic regression was utilized to determine which variables were associated with postoperative opioid prescriptions. p<.05 was considered significant. Results: We reviewed 114 patients who underwent spine surgery from January 2017 to July 2018 and 264 patients from July 2018 to January 21. There were no significant differences between the groups in age, sex, ethnicity, body mass index, number of levels fused, or preoperative opioid use. The average number of MMEs, pills prescribed and days in the first postoperative prescription decreased significantly after HB21. Multiple logistic regression revealed that the variable most predictive of MMEs and number of pills in the first postoperative prescription was postlaw status (p=.002, p=.50). Conclusions: Florida law HB21 was successful in decreasing postoperative opioid prescriptions after spine surgery, however, the need for additional progress remains. Legislation should be combined with multimodal pain regimens, as well as patient and provider education in order to further decrease postoperative opioid requirements. Future studies should include a larger number of patients treated by multiple spine surgeons across multiple institutions in order to further evaluate the effects of HB21 on postoperative opioid prescriptions.

Effects of Anticoagulant Medication on Bone-Healing.

¼: A substantial proportion of patients undergoing orthopaedic care are prescribed some form of anticoagulant medication, whether for perioperative venous thromboembolism prophylaxis or chronic anticoagulation in the setting of a cardiac or other condition. ¼: An abundance of preclinical data suggests that many commonly used anticoagulant medications may have a harmful effect on bone-healing. ¼: The orthopaedic surgeon should be informed and mindful of the added variable that anticoagulation may play in the outcomes of fracture treatment and bone-healing. ¼: Heparin and warfarin appear to have a greater detrimental impact than low-molecular-weight heparin. Factor Xa inhibitors may confer the least risk, with some studies even suggesting the potential for enhancement of bone-healing.

Transport of Vancomycin and Cefepime Into Human Intervertebral Discs: Quantitative Analyses.

STUDY DESIGN: Simulation of antibiotics transport into human intervertebral disc with intravenous infusion. OBJECTIVE: The objective of this study was to quantitatively investigate antibiotic concentrations in the disc. SUMMARY OF BACKGROUND DATA: Intravenous infusion of antibiotics is typically used to treat intervertebral disc infection in clinics. However, it is difficult to evaluate the drug concentrations within discs in vivo. METHODS: A computational model was used in this study. The variation of drug charge with pH was considered in the model. Thirty-minute infusions of two commonly used antibiotics in clinic-vancomycin and cefepime-were numerically investigated. Spatial and temporal concentration distributions of these drugs in both nondegenerated and moderately degenerated discs were calculated. RESULTS: For intravenous infusion of 1 g vancomycin and 2 g cefepime in 30 minutes repeated every 12 hours, it was predicted that vancomycin concentration in the disc fluctuated between 17.0 and 31.0 times of its minimum inhibitory concentration (1 ug/mL) and cefepime concentration fluctuated between 1.1 and 4.2 times of its minimum inhibitory concentration (i.e., 8 ug/mL) in about 2 days. It was also found that vancomycin concentration in moderately degenerated disc was lower than that in the nondegenerated disc. CONCLUSION: This study provides quantitative guidance on selecting proper dosage for treating disc infection. The method used in this study could be used to provide quantitative information on transport of other antibiotics and drugs in discs as well. LEVEL OF EVIDENCE: N/A.

Effects of diurnal loading on the transport of charged antibiotics into intervertebral discs.

The objective of this study was to quantitatively analyze the effect of diurnal loading on the transport of various charged antibiotics into negatively charged human intervertebral disc (IVD). Transport of charged antibiotics into a human lumbar disc was analyzed using a 3D finite element model. The valence (z) of the electrical charge of antibiotics varied from z = +2 (positively charged) to z = -2 (negatively charged). An uncharged antibiotic (z = 0) was used as a control. Cases with transient antibiotic concentration at disc boundaries [to mimic intravenous (IV) infusion] were simulated. Our results showed that diurnal compression increased the concentrations in the nucleus pulposus (NP) region, but degreased the concentrations in the annulus fibrosus (AF) region for all charged or non-charged drugs. The overall concentration (averaged over disc) increased with diurnal compression. The diurnal compression had more effects on negatively charged antibiotics than positively charged ones. For example, at day 5 with diurnal compression, the diurnal compression increased the concentration of negatively charged drug (z = -1) in NP by 18.3%, but only by 6.6% for positively charged one (z = +1). In AF, diurnal compression decreased the concentration by 13.2% for negatively charged drug (z = -1) versus 1.2% for positively charged one (z = +1). Note these percentages are the averaged values over day 5. This study provides quantitative information on understanding the mechanisms of charged drug transport in human IVDs.

The effect of surgically implanted metallic bullet fragments on the intervertebral disc using a canine model☆.

PURPOSE: To characterize the gross, histologic, and systemic changes caused by implantation of metal fragments commonly used in commercial bullets into the intervertebral disc. BACKGROUND CONTEXT: Long-term complications of retained bullet fragments in the spine have been documented in the literature; however, the impact of different metal projectiles on the intervertebral disc has not been described. This study was performed to assess the local effects of the metallic bullet fragments on the intervertebral disc and their systemic effects regarding metal ion concentrations in serum and solid organs. STUDY DESIGN: Animal Model Study. METHODS: Funding for this project was provided by the Cervical Spine Research Society in the amount of $10,000. Copper, lead, and aluminum alloys from commercially available bullets were surgically implanted into sequential intervertebral discs in the lumbar spine of six canines. Kirschner wire implantation and a sham operation were performed as controls. Radiographs were performed to confirm the location of the bullets. Animals were sacrificed at 4, 6, and 9 months postimplantation. Whole blood, plasma, cerebrospinal fluid, kidney tissue, and liver tissue samples were analyzed for copper and lead concentrations. Histologic and gross samples were examined at the time of sacrifice. RESULTS: Significant tissue reactions were noted in the discs exposed to copper and lead. Copper resulted in significantly more severe disc degeneration than either the lead or aluminum alloy. In the short interval follow-up of this study, no statistically significant trend was observed in whole blood, plasma, cerebrospinal fluid, and tissue levels. CONCLUSION: This study demonstrates that the canine intervertebral disc is differentially susceptible to metallic fragments depending on the composition. Trends were noted for increasing levels of lead and copper in liver tissue samples although statistical significance could not be reached due to short time interval and small sample size. The metallic composition of retained fragments can be a determining factor in deciding on surgical intervention.

An epidural steroid injection in the 6 months preceding a lumbar decompression without fusion predisposes patients to post-operative infections.

BACKGROUND: To determine if the timing of a lumbar epidural steroid injection (LESI) effects rates of post-operative infection in patients receiving a non-fusion lumbar decompression (LDC) due to degenerative disc disease (DDD). Lumbar pain due to DDD can frequently be temporized or definitively treated with epidural injections. While there is ample literature regarding the infection risks associated with corticosteroid injections prior to hip/knee replacements, there are few studies relating to the spine. METHODS: A nationwide insurance database was queried to identify those who underwent LDC for DDD without instrumentation [2005-2014]. Lumbar fusion procedures were excluded. From this group those with a history of a LESI were identified and matched to a control group without a history of LESI. Four separate cohorts were examined: (I) LDC and no LESI within 6 months (control); (II) LDC performed within 0-1 month after LESI; (III) LDC between 1 and 3 months after LESI; (IV) LDC performed between 3 and 6 months after LESI. RESULTS: There was an increased odds of a 90-day postoperative infection if the LESI was within the 1-3 months (OR =4.69; P<0.001) and 3-6 months (OR =5.33; P<0.001) interval prior to the LDC. CONCLUSIONS: While LESI is helpful for possibly delaying or avoid lumbar surgery, it may predispose patients to higher infection rates following lumbar decompressions without fusion. Surgeons and pain management specialist should counsel patients on these risks and.

Diffusion of antibiotics in intervertebral disc.

Delivering charged antibiotics to the intervertebral disc is challenging because of the avascular, negatively charged extracellular matrix (ECM) of the tissue. The purpose of this study was to measure the apparent diffusion coefficient of two clinically relevant, charged antibiotics, vancomycin (positively charged) and oxacillin (negatively charged) in IVD. A one-dimensional steady state diffusion experiment was employed to measure the apparent diffusion coefficient of the two antibiotics in bovine coccygeal annulus fibrosus (AF) tissue. The averaged apparent diffusion coefficient for vancomycin under 20% compressive strain was 7.94 ±â€¯2.00 × 10-12 m2/s (n = 10), while that of oxacillin was 2.26 ±â€¯0.68 × 10-10 m2/s (n = 10). A student's t-test showed that the diffusivity of vancomycin was significantly lower than that of oxacillin. This finding may be attributed to two factors: solute size and possible binding effects. Vancomycin is approximately 3 times larger in molecular weight than oxacillin, meaning that steric hindrance likely plays a role in the slower transport. Reversible binding between positive vancomycin and the negative ECM could also slow down the rate of diffusion. Therefore, more investigation is necessary to determine the specific relationship between net charge on antibiotic and diffusion coefficients in IVD. This study provides essential quantitative information regarding the transport rates of antibiotics in the IVD, which is critical in using computational modeling to design effective strategies to treat disc infection.

The most influential publications in cervical myelopathy.

Management of cervical myelopathy (CM) has continued to evolve through a better understanding of the long-term outcomes of this diagnosis as well as improved diagnostic guidelines. More recent literature continues to expand the field, but certain publications can be distinguished from others due to their lasting impact. Using the Clarivate Analytics Web of Science, search phrases were used to identify publications pertaining to CM. The fifty most cited articles were isolated. The frequency of citations, year of publication, country of origin, journal of publication, level of evidence (LOE), article type, as well as contributing authors and institutions were recorded. We also highlighted the five most cited articles (per year) from the past 10 years. Publications included ranged from 1952-2011, with the plurality of articles published during 2000-2009 (n=21; 42%). The most cited paper was Hillibrand's 1999 reporting of adjacent segment disease rates following cervical fusions, followed by Hirabayashi's 1983 review of his cervical laminoplasty outcomes. The third most cited was Brain's 1952 review of the manifestations of cervical spondylosis. Spine contributed the most publications (n=26; 52%). A LOE of III was the most common (n=30; 60%). Clinical outcome articles were the most frequent type (n=28; 56%). Osaka University (Japan) and Kazou Yonenobu had the most contributions. Ames or Fehlings were the first or last author in each of the five most influential articles from the past 10 years. This bibliometric citation analysis identifies the most influential articles regarding CM. There are few publications with a high LOE, and more high powered studies are needed. Knowledge of these "classic" publications allows for a better overall understanding of the diagnosis, treatment, and future direction of research of CM.

Kinetics of charged antibiotic penetration into human intervertebral discs: A numerical study.

Little quantitative information exists on the kinetics of charged antibiotic penetration into human intervertebral discs (IVD). This information is crucial for determining the dosage to use, timing of administration, and duration of treatment for infected IVDs. The objective of this study was to quantitatively analyze the transport of various charged antibiotics into human lumbar IVDs. Penetration of charged and uncharged antibiotics into a human lumbar disc was analyzed using a 3D finite element model. The valence (z) of the electrical charge of antibiotics varied from z=+2 (positively charged) to z=-2 (negatively charged). An uncharged antibiotic (z=0) was used as a control. Cases with intravenous (IV) administrations of different charged antibiotics were simulated. Our results showed that the electrical charge had great effects on kinetics of an antibiotic penetration into the IVD; with higher concentrations and uptakes for positively charged antibiotics than those for negatively charged ones. This study provides quantitative information on selecting antibiotics for treating intervertebral disc infections.

Posterior cervical laminoplasty in the North American Population: A minimum of two year follow-up.

BACKGROUND: The efficacy of expansile cervical laminoplasty for cervical spondylotic myelopathy has been validated in the literature. To date, however, the majority of large, long-term data in the literature have originated in Japan. Few studies have originated from North America that include follow up greater than one year, and none of these includes a single surgeon's experience. This paper presents the retrospective results of a single surgeon with an average follow up of 47 months in a large population of North American patients. METHODS: A single surgeon's series of 80 consecutive patients who underwent expansile open-door laminoplasty for cervical myelopathy was reviewed. The severity of disability was graded using the Nurick Functional Disability Score and the Miami Upper Extremity Function (MUEF) score. Patients were evaluated preoperatively, six months postoperatively, and at a minimum of 24 months postoperatively. All examinations were performed by a single physician. MRI scans of the cervical spine were obtained at four months postoperatively in all patients. Radiographs were used to evaluate postoperative lordosis. RESULTS: Average length of follow up was 47 months. Nurick scores improved from an average of 2.3 preoperatively to postoperative scores of 1.5 (p>.05) at six months and 1.4 (p>.05) at two years. MUEF scores also improved at both the six month and two year intervals. All patients had improved canal diameter on post-operative MRI scan evaluation obtained four months post-operatively. CONCLUSION: This study confirms that laminoplasty is a safe and effective treatment of cervical spondylotic myelopathy in the North American population. LEVEL OF EVIDENCE: Case Series Level IV.

National Trends in Ambulatory Surgery for Intervertebral Disc Disorders and Spinal Stenosis: A 12-Year Analysis of the National Surveys of Ambulatory Surgery.

STUDY DESIGN: A descriptive epidemiology study. OBJECTIVE: The aim of this study is to investigate changes in the utilization of ambulatory surgical procedures performed for intervertebral disc disorders and spinal stenosis between 1994 and 2006 in the United States. SUMMARY OF BACKGROUND DATA: Understanding trends in the utilization of ambulatory spine surgery may improve health care delivery in the Unites States. Epidemiologic studies evaluating national practice patterns for ambulatory spine surgery are limited. METHODS: The National Survey of Ambulatory Surgery conducted in 1994, 1996, and 2006 by the Centers for Disease Control and Prevention was analyzed to identify surgically managed patients with intervertebral disc disorders and spinal stenosis. Patients were divided into 1 of 3 groups: discectomy, laminectomy, or fusion. The data were analyzed for trends in demographics, treatment, and utilization. RESULTS: Between 1994 and 2006, the number of procedures increased by 540% for intervertebral disc disorders (6.1/100 000 capita to 34.2/100 000 capita) and 926% for spinal stenosis (0.38/100 000 capita to 3.46 per 100 000 capita). Intervertebral fusions increased from 5% of outpatient spine surgeries in 1994 to 17% in 2006. The utilization of freestanding ambulatory facilities as the location of surgery increased 340% for intervertebral disc disorders and more than 2000% for stenosis. Private insurance was the largest compensator, representing 91% of cases in 2006. An increasing proportion of females underwent surgery for intervertebral disc disorders and stenosis at these ambulatory facilities over this time period. Lumbar disc displacement remained the most common diagnosis at each time point. CONCLUSIONS: The rate of ambulatory surgery for intervertebral disc disorders and spinal stenosis increased dramatically between 1994 and 2006 based upon the National Survey of Ambulatory Surgery data, which are the most up-to-date ambulatory surgery data available. These findings may aid policy-makers and caregivers in allocating health care resources to ensure the delivery of quality patient care. LEVEL OF EVIDENCE: N/A.

Fungal Infections of the Spine.

STUDY DESIGN: Review of the literature. OBJECTIVE: To retrospectively examine the frequency of published fungal infections by species and the treatment algorithms used to eradicate the disease. SUMMARY OF BACKGROUND DATA: Fungal infections of the spine present unique challenges to the modern multispecialty treatment team. Although rare in comparison with bacterial infections, fungal infections have been increasing in incidence over the past several decades. Evidences-based practice is limited to referencing smaller case series. METHODS: MEDLINE, Scopus, and EMBASE searches were carried out by one of the authors as well as by the research desk at the University of Miami/Calder Memorial Library. We included peer-reviewed articles published between 1948 and September 2010; case reports, series, and reviews were all examined and compiled into a database. RESULTS: A total of 130 articles, representing 157 cases, were included in the review. Aspergillus (60 cases, 38.2% of the total) and Candida species (36 cases, 22.9% of the total) were the 2 most common organisms. Surgery was associated with a greater survival rate than medical management alone in patients with Aspergillus (26.9% mortality in surgical patients; 60% in medically treated patients) and Candida (0% vs. 28.6%). Overall mortality was 19.3%. The overall recurrence rate was 7.4%. Amphotericin use was associated with a higher mortality rate than azoles. CONCLUSION: Aspergillus is the most common published pathogen in fungal infections of the spine. Recent publications depicting the use of newer antifungal medications such as azoles report higher survival rates. Surgically treated patients in combination with antifungal therapy showed highest frequencies of patient survival in Aspergillus and Candida infections. LEVEL OF EVIDENCE: 3.

Characteristics and Patterns of Metastatic Disease from Chordoma.

Chordoma is a rare, slow-growing malignant tumor arising from notochordal remnants. A retrospective review of patient records at two major referral centers was undertaken to assess the incidence, location, and prognostic factors of metastatic disease from chordoma. 219 patients with chordoma (1962-2009) were identified. 39 patients (17.8%) developed metastatic disease, most frequently to lung (>50%). Median survival from the time of initial diagnosis was 130.4 months for patients who developed metastatic disease and 159.3 months for those who did not (P = 0.05). Metastatic disease was most common in the youngest patients (P = 0.07), and it was 2.5 times more frequent among patients with local recurrence (26.3%) than in those without (10.8%) (P = 0.003). Patient survival with metastatic disease was highly variable, and it was dependent on both the location of the tumor primary and the site of metastasis. Metastasis to distal bone was the most rapid to develop and had the worst prognosis.

Case reviews of infections of the spine in patients with a history of solid organ transplantation.

STUDY DESIGN: Retrospective clinical case series. OBJECTIVE: To report on the epidemiological, microbiological, and clinical characteristics of spinal infections in patients who have undergone solid organ transplantation. SUMMARY OF BACKGROUND DATA: Spine infections remain a therapeutic challenge, particularly in patients who are immunocompromised. Solid organ transplant patients represent a growing population of immunocompromised hosts. To our knowledge, no previous reports have examined the clinical characteristics spinal infections in this at-risk population in a systematic fashion. METHODS: The records of patients with a history of solid organ transplantation from January 2007 through December 2012 were identified using Current Procedural Terminology procedure codes. Patients with spine infections who have received transplants were then identified using International Classification of Diseases, Ninth Revision codes for spine infection. In addition to demographic data, we recorded medical comorbidities, immunosuppressant medications, laboratory results, culture data, treatment received, and short-term results. RESULTS: During this 6-year period, 2764 solid organ transplants were performed at our institution. Of this cohort, 6 patients (0.22%) were treated for a spinal infection. Patient's age ranged from 51 to 80 years (mean, 63 yr). All spine infections occurred within 1 year after organ transplantation. All patients had an elevated erythrocyte sedimentation rate. Only 1 patient had an elevated white blood cell count. The most common organisms were Escherichia coli and Staphylococcus. Four patients required surgical treatment. All patients had complete resolution of symptoms. CONCLUSION: Our data suggest that patients with a history of solid organ transplantation may be more susceptible to developing spine infections than the general population. The most common organisms in our cohort were E. coli and Staphylococcus. Spine infections caused by atypical organisms do also occur in the organ transplant population, as is the case in other immunocompromised patients. The identification of these organisms and timely institution of treatment remains critical in the management of this at-risk population. LEVEL OF EVIDENCE: 4.

Surgical management of lumbar degenerative spondylolisthesis.

Lumbar degenerative spondylolisthesis (DS) is a common cause of low back pain, radiculopathy, and/or neurogenic claudication. Treatment begins with a trial of nonsurgical methods, including physical therapy, NSAIDs, and epidural corticosteroid injections. Surgical treatment with decompression and fusion is recommended for patients who do not respond to this initial regimen. Although much has been published in the past two decades on the surgical management of DS, the optimal method remains controversial. Interbody fusion may improve arthrodesis rates and can be performed via numerous surgical approaches. Minimally invasive techniques continue to be developed. Particular attention to surgical management of DS in the elderly is warranted given the increasing numbers of elderly persons. Healthcare utilization in the future must take into account evidence-based medicine that establishes clinically effective practices while simultaneously being cost effective.

Biomechanical analysis of four- versus six-screw constructs for short-segment pedicle screw and rod instrumentation of unstable thoracolumbar fractures.

BACKGROUND CONTEXT: Conventionally, short-segment fusion involves instrumentation of one healthy vertebra above and below the injured vertebra, skipping the injured level. This short-segment construct places less surgical burden on the patient compared with long-segment constructs, but is less stable biomechanically, and thus has resulted in clinical failures. The addition of two screws placed in the fractured vertebral body represents an attempt to improve the construct stiffness without sacrificing the benefits of short-segment fusion. PURPOSE: To determine the biomechanical differences between four- and six-screw short-segment constructs for the operative management of an unstable L1 fracture. STUDY DESIGN: Biomechanical study of instrumentation in vertebral body cadaveric models simulating an L1 axial load injury pattern. METHODS: Thirteen intact spinal segments from T12 to L2 were prepared from fresh-frozen cadaver spines. An axial load fracture of at least 50% vertebral body height was produced at L1 and then instrumented with pedicle screws. Specimens were evaluated in terms of construct stiffness, motion, and rod strain. Two conditions were tested: a four-screw construct with no screws at the L1 fractured body (4S) and a six-screw construct with screws at all levels (6S). The two groups were compared statistically by paired Student t test. RESULTS: The mean stiffness in flexion-extension was increased 31% (p<.03) with the addition of the two pedicle screws in L1. Relative motion in terms of vertical and axial rotations was not significantly different between the two groups. The L1-L2 rod strain was significantly increased in the six-screw construct compared with the four-screw construct (p<.001). CONCLUSIONS: In a cadaveric L1 axial load fracture model, a six-screw construct with screws in the fractured level is more rigid than a four-screw construct that skips the injured vertebral body.

Sacrectomy and adjuvant radiotherapy for the treatment of sacral chordomas: a single-center experience over 27 years.

STUDY DESIGN: Retrospective cohort (case only). OBJECTIVE: To evaluate the results and survival determinants of 21 patients with sacral chordomas treated with en bloc resection and adjuvant radiotherapy. SUMMARY OF BACKGROUND DATA: There are few long-term studies on treatment of sacral chordomas with more than 20 patients, and factors related to survival are not fully understood. METHODS: Demographics, treatment, complications, and oncological outcomes were analyzed with summary statistics, hypothesis testing with Mantel-Haenszel-Cox analysis, log-rank test, Cox proportional hazard model, and Kaplan-Meier survival estimates as applicable. RESULTS: There were 12 males and 9 females with mean age of 61 years (16-79) and mean follow-up of 5.8 years (2-19.2). Tumor stage was IB in 20 and IIIB in one; mean tumor size was 10.5 cm. Fourteen patients underwent combined anterior-posterior resection and 7 posterior resection alone; 18 received adjuvant radiotherapy. After treatment, bowel and bladder control were present in 4 and 5 patients, respectively. Complications included: wound infection (4), other wound complications (9), fistula (2), deep vein thrombosis (1), and pulmonary embolism (1). Median survival was 7.2 years. Eight (40%) had local recurrence and 4 (19%) metastatic disease. Mean disease-free interval before recurrence was 2.5 years (1-5). No patient (n = 8) treated in the past 9 years has had local or distant disease. Patients treated for recurrent tumor survived 5.7 years on average (range, 0.8-9) after the first recurrence. The only risk factor for tumor recurrence was proximal tumor extent (P = 0.05) There was a statistically significant association between recurrence and survival (RR = 3.8; 95% confidence interval, 1.0-15.3; P = 0.04). CONCLUSION: Despite the complications, increased long-term survival can be achieved with treatment. Proximal tumor extent may be related to recurrence and survival. Recurrence rates have diminished over time, emphasizing the importance of an experienced multidisciplinary surgical team. LEVEL OF EVIDENCE: N/A.