Acta Neurochirurgica最新文献

Background

Suboptimal improvement or secondary deterioration is frequently observed in patients with shunted normal pressure hydrocephalus (NPH). The non-invasive tap test (“pumping-test") performed via the flushing reservoir of shunts may represent an alternative to invasive diagnostic procedures for detecting underdrainage. The aim of this study was to demonstrate its efficacy and potential to reduce the need for invasive diagnostic tests.

Methods

A prospective study was conducted on 25 NPH patients who had been shunted with a “Sprung-Reservoir” and a proGAV 2.0 and in whom underdrainage was suspected. By performing 100 pumps, approximately 20 ml of cerebrospinal fluid (CSF) was withdrawn from the ventricles. Immediate effects were assessed through gait examinations after 10 min, and changes over one week were evaluated using observation sheets completed by patients and/or caregivers. Based on the results and subsequent clinical decisions, the extent to which invasive tests could be avoided was determined.

Results

The test was feasible in all patients. It was well tolerated, with no side effects or discomfort in 21 patients. Temporary headaches occurred in 1 patient, and dizziness lasting less than 5 min was reported in 3 patients. Improvement after 10 min was observed in 11 patients; in 8 of these cases, the shunt valve was immediately downregulated. The remaining 17 patients were provided with observation sheets: 6 showed no improvement, 7 reported temporary improvement, and 4 experienced sustained improvement. Patients with temporary improvement were offered valve downregulation, while those with sustained improvement were advised to return only if new symptoms developed. Patients with no improvement were put to further follow-up and possibly offered invasive tests for further clarification. Consequently, the pumping test enabled avoidance of invasive testing in 19 cases (76%).

Conclusion

The pumping test proved to be safe, effective, and capable of providing rapid clinical feedback. The additional use of observation sheets supports the monitoring of delayed effects. More invasive and costly tests can often be avoided—76% in this study. This non-invasive tap test should be considered a first-line diagnostic procedure in cases of suspected underdrainage, at least in NPH patients, before pursuing invasive diagnostics. However, not all flushing reservoirs are suitable for this “pumping test.”

Purpose

Understanding the adverse effects of an intervention is important for evaluating its overall effect. Clinical trials mainly focus on the benefits of interventions with a risk of overlooking potential harms. Additionally, patients with severe acute brain injury frequently experience adverse events from other causes, which complicates the recording of harms in trials involving such participants. In this study, we developed a standardized registration form for recording adverse events in trial participants with severe acute brain injury using a structured Delphi process.

Methods

After developing the tool, we employed a Delphi process comprising two rounds of feedback from clinical experts in Nordic countries. In the first round, the Delphi panel received a questionnaire with a preliminary registration form, consisting of a list of 25 suggested definitions for adverse events relevant in the context of intensive care and severe acute brain injury. Based on feedback from the Delphi panel, we revised the tool and sent the revised registration form as a questionnaire in the second Delphi round.

Results

The Delphi panel consisted of 10 specialist physicians with experience in intensive care, neurosurgery or neurology. Consensus on the definition of an adverse event (defined as ≥ 70% agreement) was achieved for 27 out of the resulting 28 adverse events; for one adverse event, delirium, the level of agreement did not reach consensus in the second Delphi round; however, following revision, it was retained in the registration tool. The final version of the registration tool consisted of 28 adverse events for patients with severe acute brain injury.

Conclusion

A new tool for registration of adverse events and reactions in trial participants with severe acute brain injury was reviewed and refined by a Delphi panel of 10 Nordic neurocritical-care experts. The intention is to enhance the transparency, accuracy and consistency of reporting harms in clinical trials. Through thorough and standardized recording, the tool has the potential to improve the overall quality of clinical trials.

Purpose

Since the COVID-19 pandemic, olfactory loss has been recognized as a highly prevalent condition that greatly impacts the quality of life. Similar to other sensory implants, the idea of an olfactory implant has emerged. Evidence indicates that electrical stimulation of specific olfactory structures can evoke smell sensations. However, debates on the most appropriate anatomical target and surgical technique for implantation are still ongoing. By extrapolating data from other surgical indications, transcranial approaches appear to carry a lower risk of cerebrospinal fluid leakage and infection compared with endoscopic endonasal routes. The aim of this study was to compare two electrode placements (dorsal olfactory bulb and ventral olfactory tract) through a supraorbital keyhole craniotomy in human cadavers.

Method

Four fresh human cadavers were dissected in a staged manner. Supraorbital keyhole craniotomy was performed through an eyebrow incision and the frontal lobe was slightly retracted to allow angled (30°) endoscope insertion. An auditory brainstem implant (ABI) from MED-EL was used for electrode placement.

Results

Endoscopic placement of the electrode on the dorsal side of the olfactory bulb was achieved after orbital roof drilling in all cases, but was not stable. On the contrary, endoscopic placement of an electrode under the olfactory tract was easily achieved without drilling and the electrode was stable between the olfactory tract and the planum sphenoidale, behind the olfactory bulb.

Conclusion

Ventral olfactory tract implantation posterior to the olfactory bulb using an ABI is straightforward and is associated with satisfactory electrode stability. Such a procedure could be used for clinical pilot studies evaluating the effects of various stimulation protocols on the olfactory tract in patients with long-lasting olfactory loss.

Introduction

Selective Nerve Root Block (SNRB) is widely used for managing radicular pain, serving both therapeutic and diagnostic purposes. A complete list of all reported complications associated with SNRB has never been reported.

Aim

To map the existing evidence on complications associated with lumbar SNRB.

Methods

A scoping review was conducted of peer-reviewed studies on complications associated with transforaminal or foraminal lumbar SNRB in adults with degenerative spine conditions. A systematic search was performed across six databases on 9th of September 2024. Two independent reviewers screened studies for eligibility.

Results

Of the 6,939 screened studies, 118 met the inclusion criteria, comprising a total of 15,817 patients and 72,518 SNRB procedures. A total of 145 distinct complication types and 4,439 complications were identified. Of these, 5.2% were classified as mild/moderate and 0.2% as severe according to the CTCAE grading system. The rate of complications for each study varied substantially, ranging from 0.2% to 73% calculated per procedure. Across all studies, the overall adjusted complication rate was 5.4% per procedure and 5.8% per patient. The most frequent were intravascular injection, vasovagal reactions, and central steroid effect. Severe events, including infection and paralysis, were rare (≤ 0.03%).

Discussion and conclusion

The SNRB procedure has a low complication rate, with serious complications being rare. This scoping review highlights the heterogeneous complication data in publications. Standardized guidelines for SNRB complication reporting are warranted.

Purpose

Stereotactic-guided biopsy remains the gold standard for diagnosing intracranial lesions not amenable to surgical resection. Frameless techniques, such as the VarioGuide® system (Brainlab AG, Munich, Germany), offer a minimally invasive alternative, typically using MRI-based navigation. However, MRI-based navigation may be affected by geometric distortions that impair targeting precision. CT imaging provides superior geometric fidelity. This retrospective analysis evaluates the accuracy of frameless stereotactic biopsies in clinical routine. Patients were grouped based on the imaging modality used for neuronavigation—either MRI-only or MRI-CT fusion—allowing secondary comparison between both approaches.

Methods

In this retrospective cohort study, 99 patients who underwent frameless stereotactic biopsy between February 2022 and September 2024 were analysed. Patients were grouped by neuronavigation modality: CT-MRI fusion–based (n = 18) and MRI-only (n = 81). Accuracy was assessed by measuring entry and target deviations using postoperative CT. Lesion volume, depth, procedure duration, and complication rates were also evaluated.

Results

Entry and targeting accuracy was comparable between groups (entry deviation: 5.2 ± 3.9 mm vs. 5.4 ± 3.0 mm, p = 0.84; target deviation: 4.2 ± 3.0 mm vs. 4.4 ± 2.7 mm, p = 0.85). Lesion volume and target depth showed no significant differences. No statistically significant differences in complication rates were observed between groups (27.8% vs. 11.1%, p = 0.14).

Conclusion

MRI-only and CT-MRI fusion–based frameless stereotactic biopsies showed no statistically significant difference in targeting accuracy. While CT-based registration may theoretically reduce distortion-related errors, this was not reflected in our data. The choice of imaging modality should therefore be guided by clinical context and imaging availability. Further prospective studies are needed to clarify the value of CT integration in specific clinical scenarios.

Purpose

to comprehensively and hierarchically assess risk factors for recurrence requiring reoperation (RrR) in chronic subdural hematoma (cSDH) in the era of middle meningeal artery embolization (MMAE).

Methods

Patients treated for a cSDH from January 2019 to October 2024 at Fondazione Gemelli research hospital were considered for inclusion. Clinical, coagulation, radiological, and treatment factors were recorded. MMAE was performed systematically from October 2022, using polyvinyl alcohol (PVA) particles injected directly from the main trunk of MMA.

The dataset comprised 45 quantitative and qualitative variables for each cSDH. Variables showing statistical significance (p-value < 0.05) were selected as covariates in two supervised learning frameworks to predict the RrR (outcome, Y): (i) Classification and Regression Tree (CART) and (ii) Random Forest (RF) classifier.

Results

500 patients were eligible and 233 were included, resulting in 283 treated cSDHs (mean follow-up: 119 days); 129 underwent adjuvant MMAE. 50 cSDH had a RrR (mean time to recurrence: 47 days), of which 41 (82%) in the non-embolized group and 9 (18%) in the embolized group (p-value < 0.001). Adjuvant embolization was the strongest factor associated with RrR, significantly reducing the risk for reintervention. Markwalder grading scale, preoperative cSDH volume, and platelet count (PLT) are strong predictors in non-embolized patients. A critical PLT cut-off of 229 × 10⁹/L strongly impacts RrR risk for substantial cSDH volumes.

Conclusions

The present results support the routine use of MMAE and the correction of PLT in relation to cSDH volume.

Intraneural ganglion cysts (IGCs) are benign, mucinous lesions that are often found within the epineurium of peripheral nerves, causing mononeuropathy due to nerve compression. These cysts arise from synovial fluid tracking from an adjacent synovial joint along an articular nerve branch to the parent nerve, as proposed by the unifying articular theory. This theory has transformed the understanding of IGCs from their being considered as isolated nerve lesions but as joint-related pathologies. The emphasis of identifying the cyst’s origin and its connection to the neighboring joint has shifted the surgical strategy from evacuation of the cyst to addressing the origin of the cyst and its articular branch connection. The role of high resolution imaging in both detection and surgical planning is thereby critical, because in some cysts (i.e. affecting the peroneal and tibial nerves in the knee region), the cyst may be intraneural or extraneural and arise from different joints. In this article, we summarize the magnetic resonance imaging (MRI) signs for IGCs and introduce the concept of phase-based signs which are all explained by pathoanatomic and pathophysiologic principles underlying the unifying articular theory. These signs, in turn, thave expanded our understanding, changed our clinical practice, and advanced the field.

Background

The endoscopic transorbital approach (ETOA) is being established as a new corridor for the lateral portion of the anterior and middle skull base. One of the main concerns is the risk of ophthalmological complications due to orbital retraction. Removal of the lateral orbital rim (LOR) is a simple measure that widens the corridor and may diminish injuries secondary to retraction. This study analyzes the impact of LOR removal on intraorbital pressure (IORP) during the stages of ETOA.

Methods

In this prospective cadaveric study, standard ETOA to the anterior and middle fossae were performed via a superior eyelid crease incision (Fig. 2). On one side, the LOR was preserved; on the other, it was removed. IORP was recorded with an intracranial pressure (ICP) probe during the entirety procedure (Fig. 3). All specimens underwent pre- and post-procedure CT to measure bone removal volume.

Results

Four specimens were used (8 sides, 4 with LOR removal, 4 without). Mean IORP was not statistically different between groups during periorbita detachment, which was prior to LOR removal (117.4 vs 91.5 mmHg, for the LOR removal group and LOR intact group respectively p = 0.217). IORP was consistently reduced in the LOR removal group in every subsequent step (Fig. 3): meningo-orbital band cutting (105.5 to 38.9 mmHg, p < 0.002), temporal fossa drilling (85.3 to 69.5 mmHg, p = 0.232), lateral greater sphenoid wing (GSW) drilling (99.8 to 49.9 mmHg, p < 0.001), medial GSW drilling (85.6 to 17.2 mmHg, p < 0.001), cavernous sinus peeling (85.6 to 3.0 mmHg, p < 0.001). LOR removal increased total bone removal volume from 6.2 cc to 9.4 cc (p = 0.05).

Conclusion

LOR removal decreased IORP, especially when working on the GSW and cavernous sinus, and significantly increased bone removal. These results support LOR removal to reduce orbital retraction stress and widen the working corridor during ETOA.

Purpose

Radiolucent carbon fiber-reinforced PEEK (CFRP) pedicle screws have improved imaging and radiation planning in spine oncology. However, these benefits are often limited by titanium cages used in combination. This study reports our initial experience using novel CFRP cages in oncologic spine surgeries, comparing their surgical feasibility, complications, and imaging performance to titanium cages.

Methods

We retrospectively analyzed 13 patients who received CFRP cages between July 2021 and May 2023. Clinical, surgical, follow-up, and imaging data were evaluated. A matched cohort with titanium cages was used to assess postoperative MRI visibility of anatomical landmarks, rated by independent reviewers.

Results

Thirteen CFRP cages were implanted (mean age 61 ± 11 years; 54% female). Indications included spinal metastases (54%) and primary bone tumors. Most procedures involved the thoracic spine (62%), followed by lumbar (23%) and cervical (15%). Median instrumentation spanned 4 segments; 62% had two-staged surgeries. Three complications occurred: 1 cage dislocation (requiring revision), 1 wound infection, and 1 post-incisional hernia. Median radiologic follow-up was 74 days, with no further dislocations. Postoperative MRI showed significantly better visibility of key spinal landmarks with CFRP cages versus titanium (p < .05, Wilcoxon signed-rank test).

Conclusion

CFRP cages are a viable alternative to titanium in oncologic spine surgery, offering comparable usability and improved postoperative imaging. These advantages may support better radiotherapy planning and complication detection, warranting further investigation.