COVID-19 and Surgical Practice in Slovenia: Managing the Crisis in Neurosurgery during the COVID-19 Pandemic.

Worldwide, the novel coronavirus disease 2019 (COVID-19) has become a significant threat to global health. Worldwide, COVID-19 has affected the health service also in Slovenia. During this time, neurosurgery is facing difficulties in its service, both in emergency and elective surgeries. In the article, we describe the anti-COVID-19 measures taken at our neurosurgical department in a medical centre in Ljubljana, Slovenia, and analysed and compared the number of emergency and elective neurosurgical procedures during the time of the pandemic.

Awake craniotomy for operative treatment of brain gliomas - experience from University Medical Centre Ljubljana.

BACKGROUND: Awake craniotomy is a neurosurgical technique that allows neurophysiological testing with patient cooperation during the resection of brain tumour in regional anaesthesia. This allows identification of vital functional (i.e. eloquent) brain areas during surgery and avoidance of their injury. The aim of the study was to present clinical experience with awake craniotomy for the treatment of gliomas at the University Medical Centre Ljubljana from 2015 to 2019. PATIENTS AND METHODS: Awake craniotomy was considered in patients with a gliomas near or within the language brain areas, in all cases of insular lesions and selected patients with lesions near or within primary motor brain cortex. Each patient was assessed before and after surgery. RESULTS: During the 5-year period, 24 awake craniotomies were performed (18 male and 6 female patients; average age 41). The patient's cooperation, discomfort and perceived pain assessed during the awake craniotomy were in majority of the cases excellent, slight, and moderate, respectively. After surgery, mild neurological worsening was observed in 13% (3/24) of patients. Gross total resection, in cases of malignant gliomas, was feasible in 60% (6/10) and in cases of low-grade gliomas in 29% (4/14). The surgery did not have important negative impact on functional status or quality of life as assessed by Karnofsky score and Short-Form 36 health survey, respectively (p > 0.05). CONCLUSIONS: The results suggest that awake craniotomy for treatment of gliomas is feasible and safe neurosurgical technique. The proper selection of patients, preoperative preparation with planning, and cooperation of medical team members are necessary for best treatment outcome.

Continuous Dynamic Mapping of the Corticospinal Tract in Motor Eloquent Tumor Surgery: Our Experience and Evaluation of the Method.

OBJECTIVE: The aim of this article is to present our experience with continuous dynamic mapping (CDM) of the corticospinal tract (CST) when removing tumors in motor eloquent regions. METHODS: We studied 44 patients with a brain tumor adjacent to the CST where CDM was used. The mapping probe was integrated at the tip of the suction device. Thresholds for eliciting MEPs were recorded. In all patients, along with CDM, MEPs to direct cortical stimulation were also monitored throughout the operation. Motor function was assessed preoperatively, after the procedure and on discharge. RESULTS: In the series, there were 37 patients with gliomas, six with brain metastasis, and one with cavernoma. The threshold to elicit MEPs in CDM was >20 mA in 17 cases, 16-20 mA in six cases, 11-15 mA in six cases, 6-10 mA in nine cases and 2-5 mA in six cases. MEPs to direct cortical stimulation were preserved in all patients. In three cases a new temporary motor deficit was noted. No new permanent motor deficit occurred. Gross total resection was reached in 57% of cases. CONCLUSIONS: From our experience, the combined use of CDM and MEPs to direct cortical stimulation improves the safety of surgery in the proximity of the CST, and at the same time offers the possibility of higher rates of gross total resection.

Concurrent intradural meningioma and schwannoma at the same lumbar level in a patient without neurofibromatosis: a case report.

Spinal schwannomas coexisting with meningiomas in patient without neurofibromatosis are extremely rare lesions. Here we present a case of 59-year-old patient with concurrent spinal meningioma and schwannoma at L1-L2 spinal level. This is the first case of the concurrent intradural tumours at the same lumbar level.

Importance of the telemedicine network for neurosurgery in Slovenia.

The number of invasive procedures in medicine is increasing, as is the employment of new technological achievements. In the era of information-communication technology, one such achievement is also the telemedicine network. In Slovenia, it is known as the Telekap (TeleStroke) network, which was primarily designed for fast and efficient management of stroke patients. In the neurosurgical community, the system is frequently used also for conveying vital information regarding subarachnoid haemorrhage and trauma. Especially in neurosurgical emergencies, this communication system offers thorough information about the extent and location of bleeding and facilitates the preoperative planning of neurosurgical interventions. From our experience so far, the system should be expanded to other neuro-centres as well to all neurosurgery departments in order to facilitate patient management, their acute hospital care, and inter-speciality collaboration.

Influence of breaching the connective sheaths of the donor nerve on its myelinated sensory axons and on their sprouting into the end-to-side coapted nerve in the rat.

The influence of breaching the connective sheaths of the donor sural nerve on axonal sprouting into the end-to-side coapted peroneal nerve was examined in the rat. In parallel, the effect of these procedures on the donor nerve was assessed. The sheaths of the donor nerve at the coaptation site were either left completely intact (group A) or they were breached by epineurial sutures (group B), an epineurial window (group C), or a perineurial window (group D). In group A, the compound action potential (CAP) of sensory axons was detected in ~10% and 40% of the recipient nerves at 4 and 8 weeks, respectively, which was significantly less frequently than in group D at both recovery periods. In addition, the number of myelinated axons in the recipient nerve was significantly larger in group D than in other groups at 4 weeks. At 8 weeks, the number of axons in group A was only ~15% of the axon numbers in other groups (p<0.05). Focal subepineurial degenerative changes in the donor nerves were only seen after 4 weeks, but not later. The average CAP area and the total number of myelinated axons in the donor nerves were not different among the experimental groups. In conclusion, myelinated sensory axons are able to penetrate the epiperineurium of donor nerves after end-to-side nerve coaption; however, their ingrowth into recipient nerves is significantly enhanced by breaching the epiperineurial sheets at the coaptation site. Breaching does not cause permanent injury to the donor nerve.

Use of 3D visualisation of medical images for planning and intraoperative localisation of superficial brain tumours: our experience.

BACKGROUND: In the present article, we assessed the role, adequacy and application accuracy of intraoperative visual guidance based on the computer 3D visualisation of preoperative medical images in the surgery of superficial brain tumours. MATERIALS AND METHODS: For 30 consecutive patients with convexity meningioma or cortical/subcortical brain tumour, we used 3D visualisation of post-contrast fast spoiled gradient recalled (FSPGR) MR images to plan optimal positions for the trepanation opening and/or corticotomy site. At the beginning of the surgery, planned positions were transferred to the scalp and the cortical surface of the patient by visually matching the 3D surfaces with the operative field. The feasibility of visual matching was assessed by counting the number of cases in which this was possible. On the exposed cortical surface, we measured the mismatch between the centre of the actual trepanation opening and the planned corticotomy site, where possible. RESULTS: During computer-assisted 3D planning, the centre of the trepanation opening, initially defined on the basis of 2D diagnostic images, was redefined in all our cases by an average repositioning distance of 19.7 mm +/- 7.6 mm. During surgery, the transfer of the planned centre of the trepanation opening and the corticotomy site was possible in all (30/30) and in 70% (19/27) of the cases, respectively. Where assessable, the mismatch between the centre of the actual trepanation opening and the planned corticotomy site was less than 1 cm in 70% of cases (12/17) and more than 2 cm in 6% (1/17) of cases. CONCLUSIONS: Intraoperative visual guidance based on 3D visualisation proved to be adequate and accurate for locating superficial brain tumours in cases where transfer of planned surgical targets to the surgical field was possible. Decision about its use should be based on preoperative computer-assisted 3D planning, in which the feasibility of visual matching during surgery can and must be assessed.

Efficacy of fluorescent tracers in retrograde labeling of cutaneous afferent neurons in the rat.

BACKGROUND: In the present study, the labeling efficacy of tracers Fluoro-ruby (FR), Fluoro-emerald (FE), True Blue (TB), Fluoro-Gold (FG), Diamidino Yellow (DY) and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) to retrogradely label the cutaneous afferent neurons in the rat was examined. METHODS: The proximal stump of the transected sural nerve was exposed for 1 hour either to one of the examined dyes (FR, FE, TB, FG, DY and DiI group) in single labeling experiments, or to mixtures of two dyes (TB-FG, FG-DiI, TB-DY and TB-DiI group) in double labeling experiments (n=5 for each group). After 10 days, dorsal root ganglia (DRGs) L3-S1 were harvested, cut to 20 microm thick longitudinal sections and all labeled neurons were counted. RESULTS: The average numbers of labeled DRG neurons in FR group (1063+/-158; mean+/-SD) and FE group (1067+/-203) were statistically significantly lower than those in TB group (2831+/-379), FG group (2802+/-134), DY group (2888+/-262) or DiI group (2900+/-278) (p<0.05). In double labeling experiments, the average number of double labeled neurons in TB-DY group (2208+/-207) was statistically significantly lower than those in TB-FG group (2775+/-316), FG-DiI group (2921+/-419), or TB-DiI group (2805+/-179) (p<0.05). CONCLUSIONS: Among examined tracers, TB, FG, DY and DiI, have the highest and similar labeling efficacy for retrograde labeling of cutaneous afferent neurons in the rat. The tracers TB, DiI and FG effectively label the same neuronal population in double labeling, therefore, their combinations are most suitable for double retrograde labeling studies of cutaneous afferent neurons in the rat.

Aging impairs collateral sprouting of nociceptive axons in the rat.

Sprouting of uninjured nociceptive axons was examined in young adult, middle aged and aged rats. Axon sprouting from the spared sural nerve, both into adjacent denervated skin and into end-to-side coapted nerve graft, was significantly higher in young rats than in aged rats. Cross-transplantations of the end-to-side coapted nerve grafts between young and aged rats demonstrated that axon sprouting from young recipient nerves into aged donor nerve grafts was significantly deteriorated, whereas the axon sprouting from aged recipient nerves into young donor nerve grafts was not statistically significantly affected. The levels of laminin polypeptides in peripheral nerves were 50-100% higher in young adult than in aged rats. However, the levels of peripherin, NGF isoforms and TrkA in skin, peripheral nerves and DRG, respectively, were not significantly reduced in aged rats. Therefore, impaired sprouting of nociceptive axons in aged rats is due rather to the alterations in peripheral neural pathways, than to the limited sprouting capacity of aged sensory neurons. Decreased levels of extracellular matrix components might be important in this respect.

Sex-related differences in the regeneration of sensory axons and recovery of nociception after peripheral nerve crush in the rat.

Sex-related differences regarding the regeneration of nociceptive axons and the recovery of nociception after sural nerve crush injury were examined in rats. The elongation rate of the fastest regenerating sensory axons in females started to increase after the first 6 days. This resulted in about 15% greater axon elongation distance at 8 days after crush in female than in male rats as determined by the nerve pinch test. The number of regenerating sensory axons in female and male rats, however, was not different. The recovery of nociception in the instep started earlier and was more extensive in females than in males during the entire 24-week recovery period, so that the pain sensitive area was finally about 20% larger in females than in males. Although ovariectomy significantly reduced plasma estradiol concentration in female rats, it did not change the elongation distance of regenerating nociceptive axons, which remained significantly greater than in male rats. Elimination of the cells in the distal nerve segment by freezing revealed that a more effective cell support in the distal nerve segment is probably responsible for faster regeneration of nociceptive axons in females than in males, rather than the circulating female sex hormones.