Evaluating osteoporosis and bone quality in the aging spine: modern considerations for surgical management in the geriatric population.

Surgical management paradigms of spinal pathologies in the aging population carry inherent substantial risks, with surgical complications being more prevalent among patients with osteoporosis compared to those with normal bone mineral density. In this narrative review, we aim to highlight important clinical understanding and considerations in perioperative evaluation and management of patients elected to undergo spinal surgery. Osteoporosis is a well-defined risk factor for mechanical complications following spinal surgery, and as such, perioperative optimization of bone health in the setting of surgery for geriatric patients remains a critical research area alongside intraoperative surgical augmentation techniques. Surgical techniques to circumvent challenges with instrumentation of poor bone mineral density have included augmentation of pedicle screw fixation, including segmental bicortical screw fixation techniques, cement augmentation with fenestrated screws, or use of expandable pedicle screws to improve bone-implant interface. Judicious selection of treatment modalities and subsequent perioperative optimization is paramount to minimize surgical complications. Contemporary guidelines and evolving paradigms in perioperative evaluation, optimization, and management of the aging spine include the advent of quantitatively evaluating computed tomography (CT) via assessment of the magnitude of Hounsfield units. Prescribing pharmacotherapeutic agents and monitoring bone health requires a multidisciplinary team approach, including endocrinologists and geriatricians to coordinate high-quality care for advanced-age patients who require surgical management of their spinal disorders.

The use of Microsurgical Exploration of the External Carotid Artery for Removal of a Retained Microcatheter After Middle Meningeal Artery Embolization Using Live Fluoroscopy: A Technical Note.

BACKGROUND: Fragmentation, disconnection, or entrapment of an in-use microcatheter during neuro-endovascular procedures is a known risk. Often a benign entity, retained catheters are not infrequently observed, but severe complications including thrombus, thromboembolic events, pseudoaneurysm, and limb ischemia have been described, necessitating retrieval. This technical case report demonstrates the safe use of an external carotid artery (ECA) approach for ligation and removal of a retained microcatheter after middle meningeal artery (MMA) embolization. This article also demonstrates the use of live intraoperative fluoroscopy as a surgical adjunct to ensure that the catheter is fully removed without any injury, shearing, or breakage during removal. METHODS: A 66-year-old male patient presented with bilateral subdural hematomas to an outside hospital. He subsequently underwent evacuation of the hematomas followed by a right-sided MMA embolization, complicated by Onyx (Medtronic, Minneapolis, MN) entrapment of the microcatheter in the MMA. The patient was asymptomatic, but there was significant concern about continuing antiplatelet/anticoagulation therapy in the presence of the subdural hematoma. We proceeded with an open surgical approach for catheter retrieval. As the catheter was withdrawn, intraoperative fluoroscopy demonstrated complete removal without any retained fragments. RESULTS: The patient recovered without event and was discharged on postoperative day 1. On follow-up the patient continued to do well without any complications from the fragment that remained in the external carotid circulation. CONCLUSIONS: This case and accompanying video demonstrates the effective use of open ECA surgical approach to retrieve the retained microcatheter after an MMA embolization. This approach allowed for safe and effective removal of the microcatheter while significantly reducing complication risks.

Image-localized biopsy mapping of brain tumor heterogeneity: A single-center study protocol.

Brain cancers pose a novel set of difficulties due to the limited accessibility of human brain tumor tissue. For this reason, clinical decision-making relies heavily on MR imaging interpretation, yet the mapping between MRI features and underlying biology remains ambiguous. Standard (clinical) tissue sampling fails to capture the full heterogeneity of the disease. Biopsies are required to obtain a pathological diagnosis and are predominantly taken from the tumor core, which often has different traits to the surrounding invasive tumor that typically leads to recurrent disease. One approach to solving this issue is to characterize the spatial heterogeneity of molecular, genetic, and cellular features of glioma through the intraoperative collection of multiple image-localized biopsy samples paired with multi-parametric MRIs. We have adopted this approach and are currently actively enrolling patients for our 'Image-Based Mapping of Brain Tumors' study. Patients are eligible for this research study (IRB #16-002424) if they are 18 years or older and undergoing surgical intervention for a brain lesion. Once identified, candidate patients receive dynamic susceptibility contrast (DSC) perfusion MRI and diffusion tensor imaging (DTI), in addition to standard sequences (T1, T1Gd, T2, T2-FLAIR) at their presurgical scan. During surgery, sample anatomical locations are tracked using neuronavigation. The collected specimens from this research study are used to capture the intra-tumoral heterogeneity across brain tumors including quantification of genetic aberrations through whole-exome and RNA sequencing as well as other tissue analysis techniques. To date, these data (made available through a public portal) have been used to generate, test, and validate predictive regional maps of the spatial distribution of tumor cell density and/or treatment-related key genetic marker status to identify biopsy and/or treatment targets based on insight from the entire tumor makeup. This type of methodology, when delivered within clinically feasible time frames, has the potential to further inform medical decision-making by improving surgical intervention, radiation, and targeted drug therapy for patients with glioma.

Surgical treatment of spinal cord compression due to Hirayama disease: illustrative case.

BACKGROUND: Hirayama disease (HD), also known as juvenile spinal muscular atrophy, is a rare condition in which flexion of the cervical neck causes compression and ischemic changes to the anterior horns of the spinal cord. Here the authors presented the first reported case of HD in North America that was successfully treated via surgical intervention. OBSERVATIONS: The patient was a 15-year boy with insidious onset upper limb weakness and atrophy. His findings were a classic presentation of HD although his complex history and relative rarity of the disease caused him to remain undiagnosed for months. After conservative management via cervical collar failed, the patient was successfully treated via C5-C7 anterior cervical discectomy and fusion. The patient's symptoms stabilized by the 3-month follow-up. LESSONS: The diagnosis of HD is easy to miss because of the lack of reporting and widespread knowledge of this condition in North America. Thus, when presented with a case of insidious onset limb weakness in a juvenile patient, HD should be placed on the differential list and verified with cervical flexion magnetic resonance imaging. Additionally, surgical intervention should be considered a safe and effective option for HD when conservative methods have failed.

Anterior Thoracic Diskectomy and Fusion: Surgical Technique and Anatomic Considerations.

Ossification of the posterior longitudinal ligament (OPLL) is a rare condition that can lead to progressive spinal cord compression.1 Currently, surgical decompression remains the optimal treatment in symptomatic patients.2,3 In cases with significant thoracic stenosis and concern for ventral erosion of the dura, an anterior approach may be necessary for direct decompression.4 In Video 1, we demonstrate the successful application of a multidisciplinary approach for surgical resection of a large OPLL lesion located at the T2-3 disk space. A 37-year-old female with medical history significant for rickets presented a year after a fall with bilateral lower extremity paraparesis and saddle anesthesia. Exposure consisted of a manubrial window, followed by thoracic diskectomy and fusion with drilling of the calcified posterior longitudinal ligament. Major steps within this video include 1) a summary of the patient presentation and preoperative imaging, 2) exposure of thoracic vertebrae via a manubrial window approach, 3) thoracic diskectomy and fusion with take-down of calcified posterior longitudinal ligament, and 4) a review of the postoperative imaging. The patient tolerated the procedure well with immediate relief of symptoms and was subsequently discharged on postoperative day 1 with no complications. This operative video illustrates the technical steps and capabilities of an anterior approach, achieving near-complete gross total resection of an OPLL lesion using a multidisciplinary approach. The patient consented to this procedure.

Clinical outcomes of first- and second-generation hydrogel coils compared with bare platinum coils: a systematic literature review.

Endovascular coiling has revolutionized intracranial aneurysm treatment; however, recurrence continues to represent a major limitation. The hydrogel coil was developed to increase packing density and improve neck healing and therefore decrease recurrence rates. In this paper, we review treatment outcomes of first- (1HCs) and second-generation (2HCs) hydrogel coils and compare them to those of bare platinum coils (BPC). A query of multiple databases was performed. Articles with at least 10 aneurysms treated with either 1HC or 2HC were selected for analysis. Collected data included aneurysm size, rupture status, initial occlusion, initial residual neck/aneurysm, packing density, mortality, morbidity, recurrence, and retreatment rates. The primary endpoint was recurrence at final follow-up. Secondary endpoints included residual neck and dome rates as well as procedure-related complications and functional dependence at final follow-up. Studies that compared 1HC to BPC showed significant lower recurrence (24% vs. 30.8%, p = 0.02) and higher packing density (58.5% vs. 24.1%, p < 0.001) in 1HC but no significant difference in initial occlusion rate (p = 0.08). Studies that compared 2HC to BPC showed lower recurrence (6.3% vs. 14.3%, p = 0.007) and retreatment rates (3.4% vs. 7.7%, p = 0.010) as well as higher packing density (36.4% vs. 29.2%, p = 0.002) in 2HC, with similar initial occlusion rate (p = 0.86). The rate of complications was not statistically different between HC (25.5%) and BPC (22.6%, p = 0.06). Based on our review, the 1HC and 2HC achieved higher packing density and lower recurrence rates compared to BPC. The safety profile was similar between both groups.

A comparison of treating physician versus independent core lab assessments of post-aneurysm treatment imaging outcomes: an analysis of prospectively collected data from a randomized trial.

OBJECTIVE: Aneurysm occlusion has been used as surrogate marker of aneurysm treatment efficacy. Aneurysm occlusion scales are used to evaluate the outcome of endovascular aneurysm treatment and to monitor recurrence. These scales, however, require subjective interpretation of imaging data, which can reduce the utility and reliability of these scales and the validity of clinical studies regarding aneurysm occlusion rates. Use of a core lab with independent blinded reviewers has been implemented to enhance the validity of occlusion rate assessments in clinical trials. The degree of agreement between core labs and treating physicians has not been well studied with prospectively collected data. METHODS: In this study, the authors analyzed data from the Hydrogel Endovascular Aneurysm Treatment (HEAT) trial to assess the interrater agreement between the treating physician and the blinded core lab. The HEAT trial included 600 patients across 46 sites with intracranial aneurysms treated with coiling. The treating site and the core lab independently reviewed immediate postoperative and follow-up imaging (3-12 and 18-24 months, respectively) using the Raymond-Roy occlusion classification (RROC) scale, Meyer scale, and recanalization survey. A post hoc analysis was performed to calculate interrater reliability using Cohen's kappa. Further analysis was performed to assess whether degree of agreement varied on the basis of various factors, including scale used, timing of imaging, size of the aneurysm, imaging modality, location of the aneurysm, dome-to-neck ratio, and rupture status. RESULTS: Minimal interrater agreement was noted between the core lab reviewers and the treating physicians for assessing aneurysm occlusion using the RROC grading scale (k = 0.39, 95% CI 0.38-0.40) and Meyer scale (k = 0.23, 95% CI 0.14-0.38). The degree of agreement between groups was slightly better but still weak for assessing recanalization (k = 0.45, 95% CI 0.38-0.52). Factors that significantly improved degree of agreement were scales with fewer variables, greater time to follow-up, imaging modality (digital subtraction angiography), and wide-neck aneurysms. CONCLUSIONS: Assessment of aneurysm treatment outcome with commonly used aneurysm occlusion scales suffers from risk of poor interrater agreement. This supports the use of independent core labs for validation of outcome data to minimize reporting bias. Use of outcome tools with fewer point categories is likely to provide better interrater reliability. Therefore, the outcome assessment tools are ideal for clinical outcome assessment provided that they are sensitive enough to detect a clinically significant change.

Quality of Life of Patients with Unruptured Intracranial Aneurysms Before and After Endovascular Coiling: A HEAT Trial Secondary Study and Systematic Review of the Literature.

BACKGROUND: The study of quality of life (QOL) in patients with asymptomatic diseases receiving interventional treatment provides an essential metric for the assessment of procedural benefits in the surgical patient population. In this study, we analyzed QOL data collected from patients with unruptured intracranial aneurysms (UIAs) before and after endovascular coiling in the HEAT Trial, alongside a systematic review on QOL in unruptured brain aneurysms. METHODS: HEAT was a randomized controlled trial comparing recurrence rates in aneurysms treated with either bare platinum coils or hydrogel coils. Patients enrolled in this trial completed a short form-36 (SF-36) QOL questionnaire before treatment and at the 3- to 12- and 18- to 24-month follow-ups. The change in QOL before and after treatment was assessed. Regression analysis evaluated the effect of select baseline characteristics on QOL change. RESULTS: A total of 270 patients were eligible for analysis. There was an increase in the role physical (P = 0.043), vitality (P = 0.022), and emotional well-being (P < 0.001) QOL components at the 18- to 24-month follow-up compared with baseline scores. Regression analysis showed that age younger than 60 and absence of serious adverse events were associated with improved social functioning and vitality. The literature review showed a mixed effect of intervention on QOL in patients with UIAs. CONCLUSIONS: Our analysis has revealed that patients with 3- to 14-mm UIAs had improvements in some physical and emotional components of QOL at 18-24 months following aneurysm coiling in the HEAT study. The literature remains indeterminate on this issue. Further studies are needed to better understand the effects of the diagnosis of UIAs and their treatment on QOL.

Investigation of ventriculoperitoneal shunt disconnection for hydrocephalus treatment.

OBJECTIVE: This investigation is aimed at gaining a better understanding of the factors that lead to mechanical failure of shunts used for the treatment of hydrocephalus, including shunt catheter-valve disconnection and shunt catheter fracture. METHODS: To determine the root cause of mechanical failure, the authors created a benchtop mechanical model to mimic mechanical stressors on a shunt system. To test shunt fracture, cyclical loading on the catheter-valve connection site was tested with the shunt catheter held perpendicular to the valve. Standard methods were used to secure the catheter and valves with Nurolon. These commercial systems were compared to integrated catheters and valves (manufactured as one unit). To test complete separation/disconnection of the shunt catheter and valve, a parallel displacement test was conducted using both Nurolon and silk sutures. Finally, the stiffness of the catheters was assessed. All mechanical investigations were conducted on shunts from two major shunt companies, assigned as either company A or company B. RESULTS: Cyclical loading experiments found that shunts from company B fractured after a mean of 4936 ± 1725 cycles (95% CI 2990-6890 cycles), while those of company A had not failed after 8000 cycles. The study of parallel displacement indicated complete disconnection of company B's shunt catheter-valve combination using Nurolon sutures after being stretched an average 32 ± 5.68 mm (95% CI 25.6-38.4 mm), whereas company A's did not separate using either silk or Nurolon sutures. During the stiffness experiments, the catheters of company B had statistically significantly higher stiffness of 13.23 ± 0.15 N compared to those of company A, with 6.16 ± 0.29 N (p < 0.001). CONCLUSIONS: Mechanical shunt failure from shunt catheter-valve disconnection or fracture is a significant cause of shunt failure. This study demonstrates, for the first time, a correlation between shunt catheters that are less mechanically stiff and those that are less likely to disconnect from the valve when outstretched and are also less likely to tear when held at an angle from the valve outlet. The authors propose an intervention to the standard of care wherein less stiff catheters are trialed to reduce disconnection.

Comorbidity of diabetes mellitus in idiopathic normal pressure hydrocephalus: a systematic literature review.

Idiopathic normal pressure hydrocephalus (iNPH) is a subtype of hydrocephalus that occurs more often in the elderly population. It is usually characterized by gait disturbance, dementia and urinary incontinence. Epidemiological studies indicate that 15.7-17.8% of iNPH patients present with type-2 diabetes mellitus (DM). A review of the primary literature shows that these occurrence rates are higher than age- and cohort-matched non-iNPH controls. This suggests that this already vulnerable patient group has an increased risk for presenting with DM compared to their non-iNPH counterparts. Postoperative outcome when treating iNPH patients is inversely related to the number of patient comorbidities and a lower comorbidity status is correlated with better outcomes. This review highlights the need for further research into the relationship between iNPH and DM and speculates on a possible mechanism for an association between the development of ventriculomegaly and the development of DM and iNPH.