Upregulation of inflammatory gene transcripts in periosteum of chronic migraineurs: Implications for extracranial origin of headache.

OBJECTIVE: Chronic migraine (CM) is often associated with chronic tenderness of pericranial muscles. A distinct increase in muscle tenderness prior to onset of occipital headache that eventually progresses into a full-blown migraine attack is common. This experience raises the possibility that some CM attacks originate outside the cranium. The objective of this study was to determine whether there are extracranial pathophysiologies in these headaches. METHODS: We biopsied and measured the expression of gene transcripts (mRNA) encoding proteins that play roles in immune and inflammatory responses in affected (ie, where the head hurts) calvarial periosteum of (1) patients whose CMs are associated with muscle tenderness and (2) patients with no history of headache. RESULTS: Expression of proinflammatory genes (eg, CCL8, TLR2) in the calvarial periosteum significantly increased in CM patients attesting to muscle tenderness, whereas expression of genes that suppress inflammation and immune cell differentiation (eg, IL10RA, CSF1R) decreased. INTERPRETATION: Because the upregulated genes were linked to activation of white blood cells, production of cytokines, and inhibition of NF-κB, and the downregulated genes were linked to prevention of macrophage activation and cell lysis, we suggest that the molecular environment surrounding periosteal pain fibers is inflamed and in turn activates trigeminovascular nociceptors that reach the affected periosteum through suture branches of intracranial meningeal nociceptors and/or somatic branches of the occipital nerve. This study provides the first set of evidence for localized extracranial pathophysiology in CM. Ann Neurol 2016;79:1000-1013.

Abdominal insufflation for laparoscopy increases intracranial and intrathoracic pressure in human subjects.

BACKGROUND: Laparoscopy has emerged as an alternative to laparotomy in select trauma patients. In animal models, increasing abdominal pressure is associated with an increase in intrathoracic and intracranial pressures. We conducted a prospective trial of human subjects who underwent laparoscopic-assisted ventriculoperitoneal shunt placement (lap VPS) with intraoperative measurement of intrathoracic, intracranial and cerebral perfusion pressures. METHODS: Ten patients undergoing lap VPS were recruited. Abdominal insufflation was performed using CO2 to 0, 8, 10, 12 and 15 mmHg. ICP was measured through the ventricular catheter simultaneously with insufflation and with desufflation using a manometer. Peak inspiratory pressures (PIP) were measured through the endotracheal tube. Blood pressure was measured using a noninvasive blood pressure cuff. End-tidal CO2 (ETCO2) was measured for each set of abdominal pressure level. Pressure measurements from all points of insufflation were compared using a two-way ANOVA with a post hoc Bonferroni test. Mean changes in pressures were compared using t test. RESULTS: ICP and PIP increased significantly with increasing abdominal pressure (both p < 0.01), whereas cerebral perfusion pressure (CPP) and mean arterial pressure did not significantly change with increasing abdominal pressure over the range tested. Higher abdominal pressure values were associated with decreased ETCO2 values. CONCLUSION: Increased ICP and PIP appear to be a direct result of increasing abdominal pressure, since ETCO2 did not increase. Though CPP did not change over the range tested, the ICP in some patients with 15 mmHg abdominal insufflation reached values as high as 32 cmH2O, which is considered above tolerance, regardless of the CPP. Laparoscopy should be used cautiously, in patients who present with baseline elevated ICP or head trauma as abdominal insufflation affects intracranial pressure.

Three-dimensional brain MRI for DBS patients within ultra-low radiofrequency power limits.

BACKGROUND: For patients with deep brain stimulators (DBS), local absorbed radiofrequency (RF) power is unknown and is much higher than what the system estimates. We developed a comprehensive, high-quality brain magnetic resonance imaging (MRI) protocol for DBS patients utilizing three-dimensional (3D) magnetic resonance sequences at very low RF power. METHODS: Six patients with DBS were imaged (10 sessions) using a transmit/receive head coil at 1.5 Tesla with modified 3D sequences within ultra-low specific absorption rate (SAR) limits (0.1 W/kg) using T2 , fast fluid-attenuated inversion recovery (FLAIR) and T1 -weighted image contrast. Tissue signal and tissue contrast from the low-SAR images were subjectively and objectively compared with routine clinical images of six age-matched controls. RESULTS: Low-SAR images of DBS patients demonstrated tissue contrast comparable to high-SAR images and were of diagnostic quality except for slightly reduced signal. CONCLUSIONS: Although preliminary, we demonstrated diagnostic quality brain MRI with optimized, volumetric sequences in DBS patients within very conservative RF safety guidelines offering a greater safety margin.

Factors Associated with Extended Hospitalization in Patients Who Had Adjuvant Middle Meningeal Artery Embolization After Conventional Surgery for Chronic Subdural Hematomas.

BACKGROUND: This study aims to evaluate the length of stay (LOS) in patients who had adjunct middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH) after conventional surgery and determine the factors influencing the LOS in this population. METHODS: A retrospective review of 107 cases with MMAE after conventional surgery between September 2018 and January 2024 was performed. Factors associated with prolonged LOS were identified through univariable and multivariable analyses. RESULTS: The median LOS for MMAE after conventional surgery was 9 days (IQR = 6 - 17), with a 3-day interval between procedures (IQR = 2 - 5). Among 107 patients, 58 stayed ≤9 days, while 49 stayed longer. Univariable analysis showed the interval between procedures, type of surgery, MMAE sedation, and the number of complications associated with prolonged LOS. Multivariable analysis confirmed longer intervals between procedures (OR=1.52; p<0.01), ≥ 2 medical complications (OR=13.34; p=0.01), and neurological complications (OR=5.28; p=0.05) were independent factors for lengthier hospitalizations. There was a trending association between general anesthesia during MMAE and prolonged LOS (p=0.07). Subgroup analysis revealed diabetes (OR=5.25; p=0.01) and ≥ 2 medical complications (OR=5.21; p=0.03) correlated with a LOS over 20 days, the 75th percentile in our cohort. CONCLUSION: The interval between procedures and the number of medical and neurological complications were strongly associated with prolonged LOS in patients who had adjunct MMAE after open surgery. Reducing the interval between the procedures and potentially performing both under one anesthetic may decrease the burden on patients and shorten their hospitalizations.

Public health insurance, frailty, and lack of home support predict rehab discharge following elective anterior cervical discectomy and fusion.

BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) is a commonly-performed and generally well-tolerated procedure used to treat cervical disc herniation. Rarely, patients require discharge to inpatient rehab, leading to inconvenience for the patient and increased healthcare expenditure for the medical system. PURPOSE: The objective of this study was to create an accurate and practical predictive model for, as well as delineate associated factors with, rehab discharge following elective ACDF. STUDY DESIGN: This was a retrospective, single-center, cohort study. PATIENT SAMPLE: Patients who underwent ACDF between 2012 and 2022 were included. Those with confounding diagnoses or who underwent concurrent, staged, or nonelective procedures were excluded. OUTCOME MEASURES: Primary outcomes for this study included measurements of accuracy for predicting rehab discharge. Secondary outcomes included associations of variables with rehab discharge. METHODS: Current Procedural Terminology codes identified patients. Charts were reviewed to obtain additional demographic and clinical characteristics on which an initial univariate analysis was performed. Two logistic regression and two machine learning models were trained and evaluated on the data using cross-validation. A multimodel logistic regression was implemented to analyze independent variable associations with rehab discharge. RESULTS: A total of 466 patients were included in the study. The logistic regression model with minimum corrected Akaike information criterion score performed best overall, with the highest values for area under the receiver operating characteristic curve (0.83), Youden's J statistic (0.71), balanced accuracy (85.7%), sensitivity (90.3%), and positive predictive value (38.5%). Rehab discharge was associated with a modified frailty index of 2 (p=.007), lack of home support (p=.002), and having Medicare or Medicaid insurance (p=.007) after correction for multiple hypotheses. CONCLUSIONS: Nonmedical social determinants of health, such as having public insurance or a lack of support at home, may play a role in rehab discharge following elective ACDF. In combination with the modified frailty index and other variables, these factors can be used to predict rehab discharge with high accuracy, improving the patient experience and reducing healthcare costs.

Outcome of Chronic Subdural Hematoma Intervention in Patients on Long-Term Antiplatelet Therapy-A Propensity Score Matched Analysis.

BACKGROUND: Patients presenting with chronic subdural hematomas (cSDHs) and on antiplatelet medications for various medical conditions often complicate surgical decision making. OBJECTIVE: To evaluate risks of preprocedural and postprocedural antiplatelet use in patients with cSDHs. METHODS: Patients with cSDH who were treated between January 2006 and February 2022 at a single institution with surgical intervention were identified. A propensity score matching analysis was then performed analyzing length of hospitalization, periprocedural complications, reintervention rate, rebleeding risk, and reintervention rates. RESULTS: Preintervention, 178 patients were on long-term antiplatelet medication and 298 were not on any form of antiplatelet. Sixty matched pairs were included in the propensity score analysis. Postintervention, 88 patients were resumed on antiplatelet medication, whereas 388 patients did not have resumption of antiplatelets. Fifty-five pairs of matched patients were included in the postintervention propensity score analysis. No significant differences were found in length of hospitalization (7.8 ± 4.2 vs 6.8 ± 5.4, P = .25), procedural complications (3.3% vs 6.7%, P = .68), or reintervention during the same admission (3.3% vs 5%, P = 1). No significant differences were seen in recurrence rate (9.1% vs 10.9%, P = 1) or reintervention rate after discharge (7.3% vs 9.1%, P = 1) in the postintervention group. CONCLUSION: Preintervention antiplatelet medications before cSDH treatment do not affect length of hospitalization, periprocedural complications, or reintervention. Resumption of antiplatelet medication after cSDH procedures does not increase the rebleeding risk or reintervention rate.

Effect of long-term anticoagulant therapy on the outcome of chronic subdural hematoma: a propensity score-matched analysis.

OBJECTIVE: Chronic subdural hematomas (cSDHs) are particularly common in older adults who have increased risk of falls and the conditions that require anticoagulants (ACs). In such cases, clinicians are often left with the dilemma of co-managing the cSDH and the ongoing need for ACs. METHODS: Patients who underwent surgical management for cSDH at the authors' institution between January 2006 and June 2022 were identified. Propensity score-matched analysis was used to obtain a balance in patients who were on ACs before the procedure versus those who were not, and in patients who were on ACs postprocedure versus those who were not. Length of hospitalization, periprocedural complications, reintervention rate during the same admission, rebleeding risk, and reintervention rates after discharge were compared. RESULTS: In total, 104 patients were on long-term ACs before the procedure, whereas 372 were not. After matching, 55 pairs were included in the analysis. Postprocedure, 74 patients were started on long-term ACs; the rest were not. A total of 49 patients in each group were then included in the analysis after matching. Comparing the preprocedure AC group with the non-AC group, no significant differences were found in length of hospitalization (8.5 ± 6.7 days vs 8.1 ± 7.7 days, p = 0.75), periprocedural complications (7.3% vs 7.3%, p > 0.99), or reintervention during the same admission (1.8% vs 5.5%, p = 0.31). In the comparison of postprocedure AC and non-AC groups, no significant differences were seen in recurrence rate (8.2% vs 14.3%, p = 0.52), reintervention rate after discharge (4.1% vs 14.3%, p = 0.16), or disability (i.e., mRS ≤ 2; 83.7% vs 89.8%, p = 0.55). CONCLUSIONS: Being treated with long-term ACs before cSDH procedures does not affect length of hospitalization, periprocedural complications, or reintervention during the same admission. Similarly, administration of long-term ACs after a procedure for cSDH does not increase rebleeding risk or reintervention rate. Patients who are on long-term ACs can have similar interventions to those who are not on ACs. In addition, it is safe to restart patients on AC agents in a 7- to 14-day window after admission for cSDH with or without acute/subacute components.

Reduced recurrence of chronic subdural hematomas treated with open surgery followed by middle meningeal artery embolization compared to open surgery alone: a propensity score-matched analysis.

OBJECTIVE: Middle meningeal artery embolization (MMAE) is an emerging endovascular treatment technique with proven promising results for chronic subdural hematomas (cSDHs). MMAE as an adjunct to open surgery is being utilized with the goal of preventing the recurrence of cSDH. However, the efficacy of MMAE following surgical evacuation of cSDH has not been clearly demonstrated. The authors sought to compare the outcomes of open surgery followed by MMAE versus open surgery alone. METHODS: Patients who underwent surgical evacuation alone (open surgery-alone group) or MMAE along with open surgery for cSDH (adjunctive MMAE group) were identified at the authors' institution. Two balanced groups were obtained through propensity score matching. Primary outcomes included recurrence risk and reintervention rate. Secondary outcomes included decrease in hematoma size and modified Rankin Scale (mRS) score at last follow-up. Variables in the two groups were compared by use of the Mann-Whitney U-test, paired-sample t-test, and Fisher's exact test. RESULTS: A total of 345 cases of open surgery alone and 52 cases of open surgery with adjunctive MMAE were identified. After control for subjective confounders, 146 patients treated with open surgery alone and 41 with adjunctive MMAE following open surgery with drain placement were included in the analysis. Before matching, the rebleeding risk and reintervention rate for open surgery trended higher in the open surgery alone than the open surgery plus MMAE group (14.4% vs 7.3%, p = 0.18; and 11.6% vs 4.9%, p = 0.17, respectively). No significant differences were seen in duration of radiographic or clinical follow-ups or decreases in hematoma size and mRS score at last follow-up. After one-to-one nearest neighbor propensity score matching, 26 pairs of cases were compared for outcomes. Rates of recurrence (7.7% vs 30.8%, p = 0.038) and overall reintervention (3.8% vs 23.1%, p = 0.049) after open surgery were found to be significantly lower in the adjunctive MMAE group than the open surgery-alone group. With one-to-many propensity score matching, 76 versus 37 cases were compared for open surgery alone versus adjunctive MMAE following open surgery. Similarly, the adjunctive MMAE group had significantly lower rates of recurrence (5.4% vs 19.7%, p = 0.037) and overall reintervention (2.7% vs 14.5%, p = 0.049). CONCLUSIONS: Adjunctive MMAE following open surgery can lower the recurrence risks and reintervention rates for cSDH.

Sustained dyskinesias following elective cessation and reactivation of chronic subthalamic nucleus deep brain stimulation for a surgical procedure.

OBJECTIVES: Subthalamic nucleus deep brain stimulation (STN DBS) is effective for treatment of levodopa-induced dyskinesias in patients with Parkinson's disease (PD). Medical or surgical procedures requiring electrocautery may require inactivation of the pulse generators to avoid damage to the lead or extension wire or possible reprogramming of the stimulators. This generally causes only mild and temporary disability. We report a patient with previously well-controlled dyskinesias who had severe and prolonged dyskinesias following reactivation of deep brain stimulation (DBS) following an orthopedic procedure. MATERIALS AND METHODS: Retrospective chart review. RESULTS: The patient underwent two orthopedic procedures, each requiring inactivation of DBS. After reactivation of DBS, the patient experienced severe dyskinesias that ultimately required sedation and ventilation to control large-amplitude dyskinesias. CONCLUSIONS: Clinicians caring for PD patients treated with STN DBS should be aware of the possible reappearance of severe dyskinesias arising from routine inactivation and reactivation of pulse generators for medical or surgical procedures.

Automated Lateral Ventricular and Cranial Vault Volume Measurements in 13,851 Patients Using Deep Learning Algorithms.

BACKGROUND: No large dataset-derived standard has been established for normal or pathologic human cerebral ventricular and cranial vault volumes. Automated volumetric measurements could be used to assist in diagnosis and follow-up of hydrocephalus or craniofacial syndromes. In this work, we use deep learning algorithms to measure ventricular and cranial vault volumes in a large dataset of head computed tomography (CT) scans. METHODS: A cross-sectional dataset comprising 13,851 CT scans was used to deploy U-Net deep learning networks to segment and quantify lateral cerebral ventricular and cranial vault volumes in relation to age and sex. The models were validated against manual segmentations. Corresponding radiologic reports were annotated using a rule-based natural language processing framework to identify normal scans, cerebral atrophy, or hydrocephalus. RESULTS: U-Net models had high fidelity to manual segmentations for lateral ventricular and cranial vault volume measurements (Dice index, 0.878 and 0.983, respectively). The natural language processing identified 6239 (44.7%) normal radiologic reports, 1827 (13.1%) with cerebral atrophy, and 1185 (8.5%) with hydrocephalus. Age-based and sex-based reference tables with medians, 25th and 75th percentiles for scans classified as normal, atrophy, and hydrocephalus were constructed. The median lateral ventricular volume in normal scans was significantly smaller compared with hydrocephalus (15.7 vs. 82.0 mL; P < 0.001). CONCLUSIONS: This is the first study to measure lateral ventricular and cranial vault volumes in a large dataset, made possible with artificial intelligence. We provide a robust method to establish normal values for these volumes and a tool to report these on CT scans when evaluating for hydrocephalus.

Middle Meningeal Artery Embolization Versus Conventional Treatment of Chronic Subdural Hematomas.

BACKGROUND: Middle meningeal artery (MMA) embolization is an emerging minimally invasive endovascular technique for chronic subdural hematoma (cSDH). Currently, limited literature exists on its safety and efficacy compared with conventional treatment (open-surgical-evacuation-only). OBJECTIVE: To compare MMA embolization to conventional treatment. METHODS: Retrospective analysis of patients with cSDHs treated with MMA embolization in a single center from 2018 to 2019 was performed. Comparisons were made with a historical conventional treatment cohort from 2006 to 2016. Propensity score matching analysis was used to assemble a balanced group of subjects. RESULTS: A total of 357 conventionally treated cSDH and 45 with MMA embolization were included. After balancing with propensity score matching, a total of 25 pairs of cSDH were analyzed. Comparing the embolization with the conventional treatment group yielded no significant differences in complications (4% vs 4%; P > .99), clinical improvement (82.6% vs 83.3%; P = .95), cSDH recurrence (4.3% vs 21.7%; P = .08), overall re-intervention rates (12% vs 24%; P = .26), modified Rankin scale >2 on last follow-up (17.4% vs 32%; P = .24), as well as mortality (0% vs 12%; P = .09). Radiographic improvement at last follow-up was significantly higher in the open surgery cohort (73.9% vs 95.6%; P = .04). However, there was a trend for lengthier last follow-up for the historical cohort (72 vs 104 d; P = .07). CONCLUSION: There was a trend for lower recurrence and mortality rates in the embolization era cohort. There were significantly higher radiological improvement rates on last follow-up in the surgical only cohort era. There were no significant differences in complications and clinical improvement.

Intramedullary-Extramedullary Breast Metastasis to the Caudal Neuraxis Two Decades after Primary Diagnosis: Case Report and Review of the Literature.

BACKGROUND: Intramedullary metastases to the caudal neuraxis with exophytic extension to the extramedullary space are rare. We describe the unique case of a patient with locally recurrent breast cancer who developed an intramedullary-extramedullary metastasis to the conus medullaris and cauda equina 22 years after primary diagnosis, the longest interval between primary breast cancer and intramedullary spread to date. We also reviewed the published literature on focal breast metastases to the conus medullaris or cauda equina. CASE DESCRIPTION: A 66-year-old woman with a history of node-positive estrogen receptor/progesterone receptor-positive, infiltrating ductal carcinoma diagnosed in 1997 and locally recurrent in 2007. Initial treatment included lumpectomy and targeted chemoradiation with mastectomy and hormonal therapy at recurrence. Twelve years later, she developed 6 weeks of bilateral buttock and leg pain without motor or sphincter compromise. Magnetic resonance imaging of the total spine revealed a 2 x 1.7 cm bilobed intradural, intramedullary-extramedullary, homogenously enhancing, T1-and T2-isointense lesion involving the conus medullaris and cauda equina. She underwent subtotal resection of a hormone receptor-positive breast metastasis. Her pain improved postoperatively and she was stable at 5 months. CONCLUSIONS: We provide evidence that patients who present with symptoms of spinal neurologic disease and a history of hormone receptor-positive breast cancer require high suspicion for metastatic pathology, despite significant time lapse from primary diagnosis. The tumor may involve both the intramedullary and extramedullary space, complicating resection. Symptom relief and quality of life should guide resection of metastatic lesions to the caudal neuraxis.

Risk Factors for Wire Fracture or Tethering in Deep Brain Stimulation: A 15-Year Experience.

BACKGROUND: In deep brain stimulation (DBS), tunneled lead and extension wires connect the implantable pulse generator to the subcortical electrode, but circuit discontinuity and wire revision compromise a significant portion of treatments. OBJECTIVE: To identify factors predisposing to fracture or tethering of the lead or extension wire in patients undergoing DBS. METHOD: Retrospective review of wire-related complications was performed in a consecutive series of patients treated with DBS at a tertiary academic medical center over 15 yr. RESULTS: A total of 275 patients had 513 extension wires implanted or revised. There were 258 extensions of 40 cm implanted with a postauricular connector (50.3%), 229 extensions of 60 cm with a parietal connector (44.6%), and 26 extensions 40 cm with a parietal connector (5.1%). In total, 26 lead or extension wires (5.1%) were replaced for fracture. Fracture rates for 60 cm extensions with a parietal connector, 40 cm wires with a postauricular connector, and 40 cm extensions with a parietal connector were 0.2, 1.4, and 12.9 fractures per 100 wire-years, significantly different on log-rank test. Total 16 (89%) 40 cm extension wires with a postauricular connector had fracture implicating the lead wire. Tethering occurred only in patients with 60 cm extensions with parietal connectors (1.14 tetherings per 100 wire-years). Reoperation rate correlated with younger age, dystonia, and target in the GPI. CONCLUSION: The 40 cm extensions with parietal connectors have the highest fracture risk and should be avoided. Postauricular connectors risk lead wire fracture and should be employed cautiously. The 60 cm parietal wires may reduce fracture risk but increase tethering risk.

Prognostic Factors for Adjacent Segment Disease After L4-L5 Lumbar Fusion.

BACKGROUND: Adjacent segment disease (ASD) is an important consideration during decision making for lumbar spinal fusion. OBJECTIVE: To identify risk factors for development of ASD after L4-L5 fusion and differences in incidence between rostral and caudal ASD. METHODS: We retrospectively reviewed all consecutive patients at a single institution who underwent first-time spinal fusion at the L4-L5 level for degenerative spinal disease over a 10-yr period, using posterolateral pedicular screw fixation with or without posterior interbody fusion. ASD was defined as clinical and radiographic evidence of degenerative spinal disease requiring reoperation at the level rostral (L3-L4) or caudal (L5-S1) to the index fusion. RESULTS: Among 131 identified patients, the incidence of ASD requiring reoperation was 25.2% (n = 33). Twenty-four cases (18.3% of the entire cohort) developed rostral ASD (segment L3-L4), 3 cases (2.3%) developed caudal (L5-S1), and 6 cases (4.6%) developed bilateral ASD (both rostral and caudal). Cumulatively, the incidence of caudal ASD was significantly lower than rostral ASD (P < .001). Following multivariate logistic regression for factors associated with ASD reoperation, decompression of segments outside the fusion construct was associated with higher ASD rates (odds ratio [OR] = 2.68, P = .039), as was female gender (OR = 3.55, P = .011), whereas older age was associated with lower ASD incidence (OR = 0.95, P = .011). CONCLUSION: When considering posterior L4-L5 fusion, surgeons should refrain from prophylactic procedures in the L5-S1 level, without clinical indications, because ASD incidence on that segment is reassuringly low.

Factors Predictive of Adjacent Segment Disease After Lumbar Spinal Fusion.

OBJECTIVE: Adjacent segment disease (ASD) is a long-term complication of lumbar spinal fusion. This study aims to evaluate demographic and operative factors that influence development of ASD after fusion for lumbar degenerative pathologies. METHODS: A retrospective cohort study was performed on patients undergoing instrumented lumbar fusion for degenerative disorders (spondylolisthesis, stenosis, or intervertebral disk degeneration) with a minimum follow-up of 6 months. RESULTS: Our inclusion criteria were met by 568 patients; 29.4% of patients had developed surgical ASD. Median follow-up was 2.8 years. Multivariate logistic regression analysis showed that decompression of segments outside the fusion construct had higher ASD (odds ratio = 2.6; P < 0.001), and those undergoing fusion for spondylolisthesis had lower ASD (odds ratio = 0.47; P = 0.003). CONCLUSIONS: Results of our study show that the most important surgical factor contributing to ASD is decompression beyond fused levels. Hence caution should be exercised when decompressing spinal segments outside the fusion construct. Conversely, spondylolisthesis patients had the lowest ASD rates in our cohort.

Fate of Hardware in Spinal Infections.

Background: Removal of hardware with irrigation and debridement in patients with surgical site infections (SSIs) is performed commonly. However, the removal of hardware from patients with SSIs after spinal procedures is controversial. Moreover, primary spinal infections such as spondylodiscitis may require instrumentation along with surgical debridement. The purpose of this article was to evaluate critically and summarize the available evidence related to retention of hardware in patients with deep SSIs, and the use of instrumentation in surgical treatment of primary spinal infections. Methods: A literature search utilizing PubMed database was performed. Studies reporting the management of deep SSIs after instrumented spinal procedures, and of primary spinal infections using instrumentation published in peer-reviewed journals were included. Identified publications were evaluated for relevance, and data were extracted from the studies deemed relevant. Results: Because SSIs occur typically during the early post-operative period before stable bony fusion has been achieved, the removal of instrumentation may be associated with instability of the spinal column, pseudarthrosis, progressive deformity, pain, loss of function, and deterioration in the activities of daily living (ADL). Hence, early SSIs after spinal instrumentation are usually treated without removal of hardware. Moreover, primary spinal infections such as spondylodiscitis may require surgical debridement and instrumentation in cases with associated instability. Conclusions: Retaining or using instrumentation in patients with SSIs after spinal procedures or in patients with primary spinal infections, respectively, are commonly practiced in the field of spine surgery. Further evidence is required for the development of definitive algorithms to guide spine surgeons in decision making regarding the fate of instrumentation in the treatment of spinal infections.

Bisphosphonates and parathyroid hormone analogs for improving bone quality in spinal fusion: State of evidence.

Spinal fusion is among the most commonly performed surgical procedures for elderly patients with spinal disorders - including degenerative disc disease with spondylolisthesis, deformities, and trauma. With the large increase in the aging population and the prevalence of osteoporosis, the number of elderly osteoporotic patients needing spinal fusion has risen dramatically. Due to reduced bone quality, postoperative complications such as implant failures, fractures, post-junctional kyphosis, and pseudarthrosis are more commonly seen after spinal fusion in osteoporotic patients. Therefore, pharmacologic treatment strategies to improve bone quality are commonly pursued in osteoporotic cases before conducting spinal fusions. The two most commonly used pharmacotherapeutics are bisphosphonates and parathyroid hormone (PTH) analogs. Evidence indicates that using bisphosphonates and PTH analogs, alone or in combination, in osteoporotic patients undergoing spinal fusion, decreases complication rates and improves clinical outcomes. Further studies are needed to develop guidelines for the administration of bisphosphonates and PTH analogs in osteoporotic spinal fusion patients in terms of treatment duration, potential benefits of sequential use, and the selection of either therapeutic agents based on patient characteristics.