The utility of internal spinal marking for intraoperative localisation: A systematic review.

BACKGROUND: Incorrect level spinal surgery is an avoidable complication, with significant ramifications. Several pre-operative spinal marking techniques have been described to aid intraoperative localisation. METHODS: A systematic search of Ovid MEDLINE, and EMBASE was performed from inception to July 2022. All publications describing cases of internal spinal marking were included for further analysis. 22 articles describing 503 patients satisfied our eligibility criteria. RESULTS: A number of localisation techniques, including endovascular coiling (n = 16), fiducials (n = 177), dye (n = 109), needle/fixed wire (n = 199), cement (n = 4), and gadolinium tubes (n = 1) were described. The highest rates of technical success were observed with endovascular coiling, fiducials, cement and dye (100 %), and complication rates were lowest with endovascular coiling, fiducials and cement (0 %). CONCLUSIONS: Overall, internal spinal marking was effective and safe. When considering practicality and efficacy, fiducial marking appears the optimal technique, as it can be performed in the outpatient setting under local anaesthesia. This review demonstrates the need for more targeted investigation into localisation methods in spinal surgery.

Clinical and financial burden of spinal infections in people who inject drugs.

BACKGROUND: People who inject drugs (PWID) are known to be at increased risk of infectious diseases including bacterial and blood-borne viral infections. However, there is limited literature surrounding the burden of spinal infections as a complication of injecting drug use (IDU). AIMS: To quantify the clinical and financial burden of IDU-related spinal infections. METHODS: Retrospective chart review of adult PWID with spinal infections requiring hospital admission to a tertiary health service in Melbourne, Australia between 2011 and 2019. RESULTS: Fifty-seven PWID with 63 episodes of spinal infections were identified with a median hospital stay of 47 days (interquartile range (IQR) 16; range 4-243 days). One-third of episodes required neurosurgical intervention and 11 (17%) episodes required intensive care unit admission (range 2-17 days). Staphylococcus aureus was the most common causative pathogen, present in three-quarters of all episodes (n = 47). The median duration of antibiotic regime was 59 days (IQR 42) and longer courses were associated with known bacteraemia (P = 0.048), polymicrobial infections (P = 0.001) and active IDU (P = 0.066). Predictors of surgery include neurological symptoms at presentation (relative risk (RR) 2.6; P = 0.010), inactive IDU status (RR 3.0; P = 0.002), a diagnosis of epidural abscess (RR 4.1; P = 0.001) and spinal abscess (RR ∞; P < 0.001). Completion of planned antimicrobial therapy was reported in 51 (82%) episodes. Average expenditure per episode was  A$61 577. CONCLUSIONS: Spinal infections in PWID are an underreported serious medical complication of IDU. Although mortality is low, there is significant morbidity with prolonged admissions, large antimicrobial requirements and surgical interventions generating a substantial cost to the health system.

Influence of comorbidities on treatment of unruptured intracranial aneurysms in the elderly.

Current evidence does not conclusively justify conservative management of unruptured intracranial aneurysms (UIA) in the elderly (age ≥ 65 years). To rationalise intervention, the authors investigated the role of age and comorbidity burden on treatment outcomes. A retrospective chart review for consecutive cases of UIAs treated in the elderly between 2007 and 2018 was performed. Preoperative Charlson Comorbidity Index (CCI) and Neurovascular Comorbidities Index (NCI) were calculated. Standard statistical methods with univariate and multiple logistic regression were used. A total of 123 patients (46 surgery, 77 endovascular) with 131 UIAs were treated. The mean age was 70.6 ±â€¯4.1 years, and 90 patients were female (73.1%). The mean aneurysm size was 8.6 ±â€¯5.0 mm, and the mean follow up period was 22.9 ±â€¯21.3 months. The rates of poor outcome (mRS > 1) at discharge, 6 weeks and 6 months were 9.8%, 5.8% and 3.6%, respectively. There was no difference in outcomes between surgical and endovascular treatment. Correlation and regression analyses revealed that aneurysm size, higher preoperative comorbidity index (CCI > 4), and endovascular treatment with a stent or flow diverter (p = 0.009, 0.02, and 0.005, respectively) were associated with a poor outcome. When adjusted in a multivariate analysis, only high comorbidity burden (CCI > 4) predicted unfavourable outcome (p = 0.01). Elderly patients who undergo treatment for UIAs are at high risk of postoperative deterioration. Careful preoperative case selection based on comorbidity burden, rather than chronological age, would be useful for improved risk stratification.

Interobserver Reliability of Spinal Adverse Events Severity System - Neuro (SAVES-N): A Prospective Adverse Event Reporting System for Neurosurgical Cases.

BACKGROUND: The reporting of adverse events (AEs) in neurosurgery uses inconsistent definitions and subjective grading systems. A standardized system for recording and describing AEs would allow valid comparisons to be drawn between different institutions, using different technologies, at different times. The Spinal Adverse Events Severity System - Neuro (SAVES-N) system is a modification of the well-validated SAVES-V2 system that encompasses complications from both cranial and spinal surgery. The objective of this study was to assess the interobserver reliability of SAVES-N in spinal and cranial neurosurgery. METHODS: Ten vignettes, including cranial and spinal neurosurgical cases, were assessed by groups of consultant neurosurgeons (n = 5) and neurosurgical registrars (n = 5) using the SAVES-N system. Interobserver reliability for the presence of AEs, the type of AE, and the SAVES severity grade of the AE were calculated using Gwet's AC2 and Fleiss' kappa and were interpreted using the thresholds described by Landis and Koch. RESULTS: Neurosurgeons had almost-perfect agreement (Gwet AC2 = 0.93), whereas registrars had substantial agreement (Gwet's AC2 = 0.74) in determining the presence or absence of AEs. Both neurosurgeons (Fleiss' kappa = 0.78) and registrars (Fleiss' kappa = 0.70) demonstrated substantial agreement within their groups as to the type of AE. Similarly, neurosurgeons (Gwet's AC2 = 0.94) and registrars (Gwet's AC2 = 0.81) both graded the severity of the AE with almost perfect agreement. CONCLUSIONS: The results of this study demonstrate that the scope of the well-validated SAVES-V2 system may be broadened to cranial neurosurgical cases by SAVES-N with substantial to almost-perfect interobserver reliability.

Utility of plain radiographs and MRI in cervical spine clearance in symptomatic non-obtunded pediatric patients without high-impact trauma.

PURPOSE: The optimal imaging modality for evaluating cervical spine trauma and optimizing management in the pediatric population is controversial. In pediatric populations, there are no well-established guidelines for cervical spine trauma evaluation and treatment. Currently, there is virtually no literature regarding imaging and management of symptomatic pediatric patients who present with cervical spine trauma without high-impact mechanism. This study aims to establish an optimal imaging strategy for this subgroup of trauma patients. METHODS: We performed a retrospective review of pediatric patients (aged below 18 years) who were admitted to Monash Medical Centre, Melbourne, Australia between July 2011 and June 2015, who did not suffer a high-impact trauma but were symptomatic for cervical spine injury following cervical trauma. Imaging and management strategies were reviewed and results compared. RESULTS: Forty-seven pediatric patients were identified who met the inclusion criteria. Of these patients, 46 underwent cervical spine series (CSS) plain radiograph imaging. Thirty-four cases underwent magnetic resonance imaging (MRI) and 9 patients underwent CT. MRI was able to detect 4 cases of ligamentous injury, which were not seen in CSS imaging and was able to facilitate cervical spine clearance in a further two patients whose CSS radiographs were abnormal. CONCLUSION: In this study, MRI has a greater sensitivity and specificity when compared to CSS radiography in a symptomatic pediatric low-impact trauma population. Our data call in to question the routine use of CSS radiographs in children.

Improved efficacy and reduced toxicity of doxorubicin encapsulated in sulfatide-containing nanoliposome in a glioma model.

As a glycosphingolipid that can bind to several extracellular matrix proteins, sulfatide has the potential to become an effective targeting agent for tumors overexpressing tenasin-C in their microenvironment. To overcome the dose-limiting toxicity of doxorubicin (DOX), a sulfatide-containing nanoliposome (SCN) encapsulation approach was employed to improve treatment efficacy and reduce side effects of free DOX. This study analysed in vitro characteristics of sulfatide-containing nanoliposomal DOX (SCN-DOX) and assessed its cytotoxicity in vitro, as well as biodistribution, therapeutic efficacy, and systemic toxicity in a human glioblastoma U-118MG xenograft model. SCN-DOX was shown to achieve highest drug to lipid ratio (0.5∶1) and a remarkable in vitro stability. Moreover, DOX encapsulated in SCN was shown to be delivered into the nuclei and displayed prolonged retention over free DOX in U-118MG cells. This simple two-lipid SCN-DOX nanodrug has favourable pharmacokinetic attributes in terms of prolonged circulation time, reduced volume of distribution and enhanced bioavailability in healthy rats. As a result of the improved biodistribution, an enhanced treatment efficacy of SCN-DOX was found in glioma-bearing mice compared to the free drug. Finally, a reduction in the accumulation of DOX in the drug's principal toxicity organs achieved by SCN-DOX led to the diminished systemic toxicity as evident from the plasma biochemical analyses. Thus, SCN has the potential to be an effective and safer nano-carrier for targeted delivery of therapeutic agents to tumors with elevated expression of tenascin-C in their microenvironment.

Long-term MRI findings of muslin-induced foreign body granulomas after aneurysm wrapping. A report of two cases and literature review.

Muslin-induced foreign body granulomas are rare delayed complications after wrapping of intracranial aneurysms. Few small case series have been reported, with a paucity of documented MRI findings. In addition, there are no reports on long-term radiological appearances or temporal evolution of conservatively managed patients. We thus report on the long-term radiological and clinical follow-up of two patients with asymptomatic muslin-induced foreign body granulomas after wrapping of recurrent middle cerebral arterial aneurysms. Both patients were successfully managed conservatively and remain asymptomatic three and six years after diagnosis of their granulomas. A literature review confirms that MRI features of muslin-induced foreign body granuloma are typical. Features include focal areas of elevated T2 signal with increased diffusion-weighted signal and thin rim enhancement. To the best of our knowledge, this is the first report to confirm that there is a corresponding reduction in apparent diffusion coefficient, as typical in an intracranial abscess. Thus a history of aneurysm wrapping is critical for diagnosis. Accurate clinical recognition of this exuberant inflammatory response will avoid misdiagnosis as pyogenic abscess or tumor and prevent unnecessary or invasive treatment.

Enhanced antitumor efficacy and reduced systemic toxicity of sulfatide-containing nanoliposomal doxorubicin in a xenograft model of colorectal cancer.

Sulfatide is a glycosphingolipid known to interact with several extracellular matrix proteins, such as tenascin-C which is overexpressed in many types of cancer including that of the colon. In view of the limited success of chemotherapy in colorectal cancer and high toxicity of doxorubicin (DOX), a sulfatide-containing liposome (SCL) encapsulation approach was taken to overcome these barriers. This study assessed the in vitro cytotoxicity, biodistribution, therapeutic efficacy and systemic toxicity in vivo of sulfatide-containing liposomal doxorubicin (SCL-DOX) using human colonic adenocarcinoma HT-29 xenograft as the experimental model. In vitro, SCL-DOX was shown to be delivered into the nuclei and displayed prolonged retention compared with the free DOX. The use of this nanodrug delivery system to deliver DOX for treatment of tumor-bearing mice produced a much improved therapeutic efficacy in terms of tumor growth suppression and extended survival in contrast to the free drug. Furthermore, treatment of tumor-bearing mice with SCL-DOX resulted in a lower DOX uptake in the principal sites of toxicity of the free drug, namely the heart and skin, as well as reduced myelosuppression and diminished cardiotoxicity. Such natural lipid-guided nanodrug delivery systems may represent a new strategy for the development of effective anticancer chemotherapeutics targeting the tumor microenvironment for both primary tumor and micrometastases.

Lateral surgical approach to lumbar intervertebral discs in an ovine model.

The sheep is becoming increasingly used as a large animal model for preclinical spine surgery studies. Access to the ovine lumbar intervertebral discs has traditionally been via an anterior or anterolateral approach, which requires larger wound incisions and, at times, significant abdominal retraction. We present a new minimally invasive operative technique for a far-lateral approach to the ovine lumbar spine that allows for smaller incisions, excellent visualisation of intervertebral discs, and minimal abdominal retraction and is well tolerated by animals with minimal morbidity.

Factors affecting the accuracy of ventricular catheter placement.

Despite technological improvements, ventriculoperitoneal (VP) shunts are still often complicated by malfunction, predominantly with proximal catheter obstruction. There is evidence that accurate placement of the ventricular catheter is significantly related to shunt survival. To identify possible risk factors that might lead to suboptimal shunt placement, we retrospectively reviewed the demographic data and radiological scans of 141 patients who underwent a VP shunt operation from 2005 to 2008 at our institution. We developed and validated a novel scale to assess catheter placement. Almost half (47.9%) of the catheters were "excellently" placed with the entire tip located in the cerebrospinal fluid, and the position of 25% was considered "good". However, 26.8% were less than optimally placed ("poor", "fair" or "moderate"), with 8.5% ("poor") lying entirely outside the ventricular system. Statistical analysis demonstrated that the preoperative size of the ventricles and the age of the patient at shunt insertion were the most important predictors in determining the quality of ventricular catheter placement. Further studies are required to evaluate frameless stereotaxy in optimizing shunt placement in patients with smaller ventricles.

Duration of in vivo antimicrobial activity of antibiotic-impregnated cerebrospinal fluid catheters.

OBJECTIVE: Shunt infection is a major neurosurgical concern even after 50 years of experience with shunt surgery. Staphylococcus species are responsible for the majority of cerebrospinal fluid shunt infections. In vitro, antibiotic-impregnated cerebrospinal fluid shunt catheters (AIC) have demonstrated protection against multiple staphylococcus species and strains for reasonable periods. We aim to study the longevity of antimicrobial activity of AIC in vivo by using explanted catheters. METHODS: Twenty-five AICs (rifampicin [0.054%] and clindamycin [0.15%]) were explanted from 18 patients for noninfectious reasons, from 11 to 700 days postimplantation. The catheters were set up on standardized Staphylococcus aureus culture plates to detect antimicrobial activity. Unused fresh AIC segments were used as control in each culture plates. RESULTS: Fourteen explanted AICs demonstrated persistent antimicrobial activity against staphylococcal species. Antimicrobial activity was detected for a period of implantation up to 127 days. This is longer than that predicted by in vitro models. CONCLUSION: The persistent antimicrobial activity is likely to translate to ongoing in vivo antimicrobial protection. This period of protection exceeds that during which most shunt infections occur.