Acta Neurochirurgica最新文献

Background: Various instruments are used in microvascular decompression (MVD) to mobilize offending vessels. Most instruments have straight tips for safety but provide limited ability to retract vessels toward the surgeon. To address this limitation, we developed a double-faced microprobe, designated as the "SWAN probe," to enhance maneuverability in confined operative spaces.

Methods: The instrument has a 2.5-mm upward-bending tip (1.0-mm width) with multiple curved surfaces for controlled vessel manipulation. The inner face (angled at 45° with a narrow hollow) allows secure vessel capture and retraction, whereas the outer face (angled at 60° with a broader hollow) is optimized for advancing the vessel away from the nerve. Flat lateral surfaces enable gentle lateral displacement. The sandblasted surface reduces slippage and minimizes light reflection. The microprobe was used in 51 MVD procedures for trigeminal neuralgia (TN) and hemifacial spasm (HFS). Its utility and safety were assessed based on intraoperative performance across key maneuvers.

Results: Usability scores were consistently higher than the theoretical baseline representing procedures achievable with conventional straight-tip instruments. Benefits were most apparent during proximal retraction ("pull-out") maneuvers of the superior cerebellar artery. The probe also aided Teflon sling handling and controlled arachnoid incision. No procedure-related complications attributable to the instrument were observed.

Conclusions: The double-faced microprobe allows both retraction and displacement of offending vessels, improving intraoperative maneuverability in selected situations. Within the limits of this study, the SWAN probe appears to be a safe and useful adjunct for MVD and may have broader applicability in microsurgery.

Background: Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disease characterized by ventriculomegaly and Hakim's triad. At present, symptoms can be alleviated only by cerebrospinal fluid (CSF) shunt surgery. Yet, various complications after shunting may occur, occasionally requiring repeated shunt revisions. In this retrospective, population-based study, our objective was to compare revision rates and causes for revision surgeries between adjustable shunt valve and fixed-pressure valves in iNPH patients.

Methods: Altogether 1220 patients were evaluated for possible iNPH at Kuopio University Hospital between 1991 and 2023. Probable iNPH was diagnosed in 809 patients who received their first ventriculoperitoneal shunt (VPS). Of the patient cohort, 566 were shunted using an adjustable valve (2008-2023) and 243 received a fixed pressure valve (1991-2012). Hospital records and nationwide registries were used to construct a timeline for each patient from the shunt insertion and until death (n = 430) or the end of 2023.

Results: Overall revision rate was lower in iNPH patients receiving an adjustable valve (14% vs. 30%, p < .001, 95% CI 0.27-0.56). The incidence of multiple revisions was also lower in the adjustable valve group (27% vs. 32% p = 0.002, 95% CI 0.21-0.71). The most common cause for revision was peritoneal catheter malposition in the adjustable valve group (44%) and shunt underdrainage in the fixed-pressure valve group (25%).

Conclusions: Adjustable shunt valves have decreased the need for shunt revision surgeries due to under- and overdrainage.

Purpose: Unilateral biportal endoscopy (UBE) has expanded as a minimally invasive option for spinal decompression, but complication profiles and their optimal management remain inconsistently reported. This review aimed to synthesize evidence on the incidence, prevention, and management of UBE-related complications and to propose practical management algorithms.

Methods: A PRISMA-aligned search of PubMed, Scopus, Web of Science, and Ovid identified studies (2020-2025) reporting perioperative complications in UBE. Primary inclusion criteria were biportal endoscopic spinal procedures with ≥ 50 patients and extractable complication data; secondary reviews were included for contextual synthesis. Levels of evidence (Oxford CEBM) and risk of bias (Newcastle-Ottawa Scale) were assessed for primary cohorts. Crude pooled incidences were calculated from primary cohorts only; secondary literature was analyzed qualitatively.

Results: Eighteen studies met inclusion criteria: eight primary UBE cohorts (3,433 lumbar cases) and ten secondary reviews. Across nine lumbar cohorts, crude pooled incidences were 2.4% for dural tear, about 2% for symptomatic epidural hematoma and lesion recurrence, 2.5% for incomplete decompression, 0.09% for surgical site infection, and 1.4% for reoperation, with higher rates early in the learning curve. Cervical and thoracic applications were sparsely reported and not suitable for pooled analysis. Algorithms were constructed for dural tear, epidural hematoma, incomplete decompression, and neural complications.

Conclusion: Lumbar UBE decompression appears safe and reproducible in experienced hands when standardized technical strategies are applied, but the evidence base is limited by retrospective design, heterogeneity, and concentration in high-volume centers. The proposed algorithms should be regarded as evidence-informed guidance requiring prospective validation in multicenter cohorts.

PURPOSE : Idiopathic normal pressure hydrocephalus (iNPH) is characterised by Hakim's tetrade comprising gait, balance, cognitive and urinary disturbance. As gait deteriorates early, 10-m walking tests (10MWT) before and after lumbar tap or extended lumbar drainage tests have been used to identify patients who may benefit from permanent cerebrospinal fluid diversion in the form of a ventriculoperitoneal (VP) shunt. Whether 10MWT should be performed at fast or normal pace to best predict benefit from shunting has been unclear so far. METHODS : We included 125 iNPH patients into a retrospective, longitudinal, single-centre cohort study and performed 10MWT before and after 72-h lumbar drainage, immediately after VP shunt insertion and at the 6-month, 1-year, 2-year, 3-year, 5-year and 8-year marks postoperatively. RESULTS : We found that time and step count improvements of normal and fast 10MWT before and after lumbar drainage were maintained in the first two to three years postoperatively. Furthermore, fast pace 10MWT time and step count better predicted postoperative gait improvement than normal pace 10MWT. Early responders of fast gait measures (walking pace improved by ≥ 0.1 m/s or step count improvement > 10% after lumbar drainage) were 3.91 (pace) and 6.29 (steps) times more likely to benefit from surgery as opposed to 2.64 (pace) and 1.93 (steps) times for normal walking pace. CONCLUSIONS : Our study suggests that the 10MWT should be performed at fast pace (maximum speed), and when normal and fast pace results are contradictory, the fast pace outcome should take priority.

Rosette-forming glioneuronal tumors (RGNT) are rare and novel World Health Organization grade I neoplasms that typically arise in the fourth ventricle and progress slowly. Surgical resection is the standard treatment. However, owing to their adherence to critical structures, complete resection is often not possible. The role of stereotactic radiosurgery (SRS) in the management of RGNT remains inconclusive. We present a case of tissue-confirmed RGNT successfully treated with SRS. A 24-year-old woman presented with diplopia and dysequilibrium and was subsequently diagnosed with a fourth ventricular tumor. Subtotal resection was performed at another hospital, and a tissue-based diagnosis of RGNT was made. After a multidisciplinary discussion and following the patient's willingness, single-session SRS was prescribed at a marginal dose of 12 Gy. During the subsequent 66-month follow-up period, radiologic regression of the tumor with corresponding resolution of symptoms was noted. She remained neurologically intact at her last official visit. The treatment paradigm for residual RGNT remains elusive due to its scarcity and varied presentation. We have presented our preliminary experience with a residual RGNT that was managed with SRS, attaining long-term freedom from tumor progression. SRS may be a safe, effective, and durable treatment modality for patients with RGNT.