Acta Neurochirurgica最新文献

Background

Structured laboratory-based microsurgical training is considered beneficial for junior residents before they begin to work in a neurosurgical operating room. The optimal duration of such training remains unclear. We studied the effect of a 40-h microsurgical laboratory course on the development of basic microsurgical skills among novices.

Methods

A total of 27 medical students participated in the study. Seven students (5 men, 2 women) underwent a structured microsurgical laboratory training program over four weeks. 20 students (10 women, 10 men) served as an untrained control group. None of the students had prior experience in microsuturing or working under magnification. The intervention group practiced for two hours per day, five days per week, over a four-week period. Skill development was assessed at baseline, after two weeks, and after four weeks of training with a microsuturing test task, and was monitored continuously throughout the training period with a microscraping test task. Microsurgical performance was compared between the intervention and the control groups using a test task performed under a surgical exoscope after two weeks of training. This task assessed complex depth perception and hand–eye coordination through the precise placement of a microneedle into small, concealed targets.

Results

For the microsuturing task the median time improved throughout the training (baseline: 44 min (interquartile range IQR = 22), 20 h training: 21 min (IQR = 6), 40 h training: 14 min (IQR = 4)). Similarly, the duration of the scraping task improved (baseline: 40 min (IQR 2), 20 h training: 15 min (IQR = 7), 40 h training: 13 min (IQR = 7)). The quality of work, including scraping accuracy, suture tightness and spacing, remained consistent in both tasks. In the exoscope task, the intervention group outperformed the control group (median task duration 6 min 54 s, IQR = 3 min vs 9 min 24 s, IQR = 6 min; p = 0.04).

Conclusions

Novices demonstrated rapid improvement during a 40-h microsurgical laboratory training course. Even less than 40 h of structured practice might be enough for surgical novices, such as neurosurgery residents, to learn the most basic microsurgical skills prior to assisting in the operating room.

Purpose

Surgeons’ visual and ergonomical challenges are long-standing concerns since the use of microscopes in surgical procedures. Although devices have been improved in the last few decades, the problem of narrow visual fields in high magnification surgeries persists. This study aims to identify the visual ergonomics challenges among microsurgeons and assess the need for novel assistive surgical solutions.

Methods

The study consisted of two parts: a survey and a hands-on experiment. Sixteen surgeons from neurosurgery and otolaryngology (ENT) specialties were invited to semi-structured interviews on challenges encountered when using surgical microscopes and evaluation of the two proposed technological solutions: CPM (context-preserving magnification) and IT (instrument transparency). Following a demonstration of these software solutions, a survey utilizing a Likert scale was administered. The second part of the study involved twelve practicing neurosurgeons who performed a task using a novel solution and compared it to a standard operative microscope setting.

Results

The most common challenges reported were visual obstruction of field by instruments (93.75%), blurring of structures and light reflection (81.25%), and loss of context (68.75%). 50% of surgeons agreed that adjusting zoom and focus takes a considerable amount of time from surgery and 56% stated that they had at least one episode of difficulty seeing depth. Notably, 69% of respondents expressed interest in testing prototypes of both proposed solutions in real surgery, with a particular preference for instrument transparency. Furthermore, the context-preserving magnification solution hands-on trial demonstrated a 40% reduction in task completion time for 60% of participants. However, one participant found no advantage, and others took longer to complete tasks with the solution compared to standard settings.

Conclusion

Our solution addresses the top visual challenges and instrument obstruction remains a top challenge in high magnification microsurgery. We showed that surgeons are highly likely to use novel assistive technologies that provide wider visual field and transparent instruments.

Purpose

Delayed cerebral ischaemia (DCI) and cerebral vasospasm (CVS) remain major causes of poor outcome in survivors of aneurysmal subarachnoid haemorrhage (aSAH). We aimed to investigate the safety and efficacy of intracisternal administration of nimodipine in patients suffering from symptomatic CVS refractory to treatment with induced hypertension and endovascular vasodilator therapy.

Methods

We performed a single-centre, retrospective, observational study including all patients diagnosed with refractory CVS after aSAH treated at our tertiary centre between January 2018 and December 2021 who received continuous intracisternal nimodipine. For nimodipine administration, a catheter was inserted in the optico-carotid cistern via supraorbital craniotomy. Our primary outcome was functional independence measured by the modified Rankin Scale (mRS) at 6 months. Secondary outcomes included treatment related complications and neurological outcome.

Results

We included 15 patients in total. Clinical outcome measured by the mRS at 6 months was good with 93.3% of patients showing mRS ≤ 1 (median mRS 1; range 1–4) Eight patients (53%) developed a new CVS-related neurological deficit during intrathecal nimodipine treatment and additionally received bolus intra-arterial nimodipine. Two patients (13%) developed acute subdural/epidural hematoma postoperatively, which was treated surgically in one patient. In two patients (13%), accidental dislocation of the intrathecal catheter occurred, which warranted re-operation.

Conclusion

Continuous intracisternal administration of nimodipine may be a viable rescue therapy option for patients with refractory CVS but is associated with an increased risk of treatment related complications.

Background

Common carotid artery (CCA) occlusion frequently results in compromised hemodynamics of the ipsilateral hemisphere with risk of infarction but also a lack of blood flow in the ipsilateral superficial temporal artery (STA), requiring a more complex revascularization strategy than a standard extracranial-intracranial (EC-IC) bypass when indicated.

Method

We describe the performance of a “Bonnet bypass” using a radial artery interposition graft (RAIG) from the contralateral STA to the ipsilateral middle cerebral artery (MCA). A groove is drilled in the skullcap to position the RAIG and reduce risk of mobilization and compression.

Conclusion

The “Bonnet bypass” enables a revascularization procedure when the ipsilateral STA is not available as donor vessel.

Background

Stereo-electroencephalography (SEEG) is an invasive electroencephalography method to precisely locate a seizure onset zone (SOZ). While today´s armamentarium allows any compromise between the historically strict orthogonal and oblique trajectories, the following aspects limit its effectiveness and safety. The shorter the distance from entry to the brain and target the less deviation of the electrode. The closer to orthogonal to the scull the more stable the anchor sits in the scull and deviation can be better controlled. Beyond that, limitations due to the stereotactic frame must be considered. In certain cases, a conflict between frame setup and entry point of the trajectory can arise. This conflict spurred us to explore the limits of stereotactic frame and the associated equipment needed for SEEG.

Methods

We utilize the Elekta Leksell Vantage frame (LVF) and surgical SEEG-instruments of the company AD-Tech. Planning of the trajectories is performed with a software based on MRI scans. After co-registration with stereotactical CT-angiogram coordinates for the centre-of-arc-principle to set up the LVF are generated. The frame setup focuses on the orientation of the ring-shaped z-axis, which impact SEEG electrode placement. Key factors, such as arc-angle and x-coordinate, influence instrument positioning and potential interference with the frame. Various combinations of ring-scale direction, arc alignment, arc-angle, and x-coordinate were attempted, along with the limitations of the ring angle in relation to y- and z-axis.

Results

Since 2018 our department performed 19 SEEG-implantations of in total 188 SEEG-electrodes. The average age at presentation of the 15 male and 4 female patients was 42 years (range 28 to 58). In 6 of the 19 implantation the ZD Inomed frame was used, while the other 13 cases were performed with the LVF. An average of 9 electrodes were applied using the ZD Inomed frame compared to 11 electrodes with the LVF. Both approaches aimed for bihemispheric targets. The average time of implantation of a single electrode using the ZD Inomed frame was 20,7 min, while the LVF took 4 min less (16,6 min). Other factors such as electrode repositioning or deviation and postoperative complications occurred very rarely. In at least 12 cases concerning 19 out of 188 (10.1%) electrodes an intraoperative trajectory replanning became necessary because of conflict between frame setup and entry point of the trajectory.

Conclusion

Our clinical experience confirmed that the complex planning of SEEG trajectories occasionally leads to a conflict between frame setup and entry points. The systematic analysis of the utilized stereotactic frame and SEEG-instruments can prevent replanning during surgery and improves patient’s safety and quality management.

Background

Paraclinoid aneurysms represent a challenge for neurosurgeons due to the anatomical complexity of this region and the technical difficulties involved in accessing this location.

Methods

In this work, we describe the surgical technique used to manage paraclinoid aneurysms, as exemplified through a clinical case. The distal dural ring (DDR) is exposed after the anterior clinoid process is resected extradurally. Then, the DDR is cut around the dorsal part of the carotid artery, moving toward the dura covering the optic nerve (ON). After, the lateral and ventral part of the ring is cut until the artery is freed from the dural attachment. The space between the proximal and DDR is visible and can be used as a proximal vascular control site if needed.

Conclusion

Microsurgical clipping of paraclinoid aneurysms through a pterional or a keyhole approach, combined with a systematic technique for opening the carotid rings, is an excellent strategy for exposing and clipping paraclinoid aneurysms, yielding favorable clinical and surgical outcomes.

Objective

Gross total resection is strived for in intramedullary spinal cord lesion surgery. Intraoperative neurophysiological monitoring (IONM) is the gold standard, but there is no consensus on the optimal IONM workflow. This study details our institutional workflow.

Methods

We retrospectively reviewed all adults who underwent intramedullary resection at Karolinska University Hospital, 2007–2021 (n = 70). Continuous multimodal IONM (somatosensory-evoked potentials (SSEP), motor-evoked potentials (MEP) and epidural D-waves) was conducted by an in-room neurophysiologist. Alarm thresholds were preset (≥ 50% SSEP amplitude drop/10% latency rise; ≥ 80% MEP reduction; ≥ 50% D-wave loss) and triggered a standardized four-step rescue protocol (halt manipulation, raise MAP to 80–90 mm Hg, topical papaverine, observation). Motor/sensory function, modified McCormick (mMC) grade, pain, and sphincter control were documented pre-operatively, at 3 months, and ≥ 12 months.

Results

Seventy patients were included. Most harboured ependymoma (51%), hemangioblastoma (18%) and cavernoma (8.5%). A neurophysiologist was present during every procedure. A ≥ 50% intra-operative SSEP-amplitude decrease was not followed by a sensory deficit (OR:3.0, 95% CI 0.86–10.6; p = 0.085) or mMC deterioration (OR:1.6, 0.33–7.5; p = 0.57) at either short- or long-term follow-up. In contrast, complete SSEP loss markedly increased the risk of postoperative sensory deficit (3-months-OR:25.2, 4.7–135; p < 0.001; long-term-OR 11.0, 2.8–43.8; p < 0.001) and poorer mMC grade (3-months-OR:7.8, 2.0–31; p = 0.004; long-term-OR:11.0, 2.8–43.8; p < 0.001). Loss of MEPs predicted a decline in mMC at long-term follow-up (OR:4.0, 1.06–15.1; p = 0.041).

Conclusions

Live data from continuous intraoperative neurophysiological monitoring, expertly interpreted in the OR, could potentially be used to make surgical and anesthesiologic adjustments with the goal of minimizing the risk of negative neurological outcomes. Significant associations were found between decreased or lost IONM signals and poorer sensorimotor function and mMC score at short- and long-term follow-up. Implementation of the IONM workflow is suggested in all intramedullary surgery.

Background

Many patients who suffer an aneurysmal subarachnoid hemorrhage (aSAH) are active smokers that may experience nicotine withdrawal following hospital admission. Nicotine replacement therapy (NRT) could alleviate abstinence and delirium but may have unwanted side-effects. Cerebral vasospasm (VS) is a feared complication of aSAH that can worsen outcome. The impact of NRT on VS, complications and outcome is still not fully delineated.

Methods

Retrospective study using anonymized data from a prospective quality registry. Patients smoking status, age, sex, comorbidities, along with aSAH severity were registered. Smokers were dichotomized into non-NRT and NRT groups depending on whether they had received a nicotine patch or not and subdivided into light smokers (≤ 10 cigarettes/day) and moderate to heavy smokers (> 10 cigarettes/day). We also registered radiological/sonological and clinical VS, delayed cerebral ischemia (DCI) related infarction and other common aSAH complications. Outcome was scored in terms of mortality and modified Rankin Score (mRS) at 90 days.

Results

495 patients were included; 220 received NRT. NRT was not a predictor of radiological/ultrasonological VS or DCI-related infarction. Poor outcome was more frequent in light smokers when they had received NRT (12.49% vs 29.31%) and their length of hospitalization was longer. Moderate to heavy smokers that had received NRT developed less frequently atrial fibrillation (3.4% vs 11.7%) and their length of stay at the ICU was shorter. There was no difference in thromboembolic or epileptic events, or respiratory failure between groups. There was no difference in smoking cessation at 90 days with or without NRT.

Conclusions

NRT had no impact on vasospasm or DCI-related infarction and it did not increase the frequency of complications. It seems advisable to abstain from NRT in light smokers.

Background

Persistent primitive hypoglossal artery (PPHA) is a rare embryological variant of the cerebral circulation in which the posterior circulation is supplied through a persistent embryonic carotid–basilar anastomosis. While often discovered incidentally, PPHA may have important clinical consequences when associated with atherosclerotic disease, aneurysms, or other cerebrovascular abnormalities.

Objective

To introduce a structured clinical classification system for PPHA that captures its anatomical spectrum, pathological associations, and symptomatic presentations, with the aim of improving diagnostic precision and procedural planning.

Methods

A six-category framework was developed to stratify PPHA according to its clinical and radiological features. This classification emphasizes anatomical distinctiveness and pathological relevance to facilitate risk stratification and therapeutic decision-making.

Results

The proposed classification defines six categories: (1) isolated asymptomatic PPHA, (2) PPHA with stenosis, (3) aneurysmal PPHA, (4) PPHA with carotid artery stenosis, (5) PPHA with cranial nerve compression, and (6) PPHA associated with other vascular anomalies. Organizing PPHA into these categories provides a practical system for clinical assessment and intervention planning.

Conclusion

This novel classification addresses the current absence of a standardized clinical framework for PPHA. Its adoption may enhance physician awareness, improve patient safety during cerebrovascular interventions, and aid multidisciplinary decision-making in complex neurovascular cases. Validation in clinical practice is warranted to establish its utility.

Background

Current guidelines for the treatment of severe TBI recommend maintaining a cerebral perfusion pressure (CPP) at 60–70 mmHg. In our institution, as well as others, an alternative algorithm—originally named the Lund concept—has been used. This treatment algorithm employs metoprolol and clonidine to limit CPP, accepting levels below 60 mmHg, with the aim of reducing cerebral edema. Previous reports on this algorithm have shown promising outcome in severe TBI cohorts when compared with many contemporary practices; however, no population-based studies have been conducted to validate these findings.

Research Question:

What is the outcome in adult severe TBI using the Lund Concept algorithm in a population-based cohort and how are CPP levels lower than 60 mmHg tolerated?

Methods

The study included 135 evaluable adult patients out of 171 admitted with severe TBI over a ten-year period in the southern Swedish healthcare region. Baseline data, intracranial pressure (ICP), CPP, treatment duration, surgical interventions, and administered drugs were correlated to the Glasgow Outcome Scale Extended (GOSE).

Results

The 30-day and 6-month mortality rates were 16% and 20%, respectively. A favorable outcome (GOSE 5–8) was achieved in 48% of patients. Only increasing age was associated with inferior outcomes.

Conclusion

The use of a management protocol accepting lower CPP levels than those recommended in existing guidelines was generally well tolerated with outcome in line with comparable reports.