5-ALA induced PpIX fluorescence spectroscopy in neurosurgery: a review.

The review begins with an overview of the fundamental principles/physics underlying light, fluorescence, and other light-matter interactions in biological tissues. It then focuses on 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence spectroscopy methods used in neurosurgery (e.g., intensity, time-resolved) and in so doing, describe their specific features (e.g., hardware requirements, main processing methods) as well as their strengths and limitations. Finally, we review current clinical applications and future directions of 5-ALA-induced protoporphyrin IX (PpIX) fluorescence spectroscopy in neurosurgery.

Coexistence of flavum ligament ossification with diffuse idiopathic skeletal hyperostosis in the cervical spine: Review of literature and technical note starting from a rare case.

BACKGROUND: Cervical flavum ligament ossification (C-OLF) is very rare source of myeloradiculopathy. Less than 100 cases have been reported in modern English literature up to 2020. Association between C-OLF and Diffuse Idiopathic Skeletal Hyperostosis (DISH) at cervical level has never been described. METHODS: In this article we performed a systematic review about epidemiology, physiopathology, clinical and surgical management of C-OLF. Moreover, we research its possible association with other cervical spine ligament ossification and in particular with anterior longitudinal ligament ossification. We report a case of 73 years-old woman experiencing mild cervical myeloradiculopathy caused by C6-C7 C-OLF compression and coexistence of DISH at cervico-thoracic level. A brief technical note about intraoperative management of C-OLF has also been described. RESULT: Our research found 81 previous reported case of C-OLF. The coexistence of Posterior longitudinal ligament ossification has been reported in 21.3% of C-OLF case. Conversely, we reported the first case describing the association between DISH and C-OLF. Posterior surgical decompression is the only useful treatment providing good long-term functional outcome. Instrumentation should be tailored according to pre-operative findings. CONCLUSIONS: C-OLF is a rare source of myeloradiculopathy and it may coexists with DISH probably due to alteration in the cervical mechanical stress and tendency of bone formation in patients harboring coexistent ligament ossifications. According to our result, skip en-bloc microsurgical laminectomy is safe and less invasive method to avoid complication and to provide optimal cervical spinal cord and nerve decompression avoiding CSF-leak.

Intraoperative cerebral blood flow monitoring in neurosurgery: A review of contemporary technologies and emerging perspectives.

Intraoperative monitoring of cerebral blood flow (CBF) has become an invaluable adjunct to vascular and oncological neurosurgery, reducing the risk of postoperative morbidity and mortality. Several technologies have been developed during the last two decades, including laser-based techniques, videomicroscopy, intraoperative MRI, indocyanine green angiography, and thermography. Although these technologies have been thoroughly studied and clinically applied outside the operative room, current practice lacks an optimal technology that perfectly fits the workflow within the neurosurgical operative room. The different available technologies have specific strengths but suffer several drawbacks, mainly including limited spatial and/or temporal resolution. An optimal CBF monitoring technology should meet particular criteria for intraoperative use: excellent spatial and temporal resolution, integration in the operative workflow, real-time quantitative monitoring, ease of use, and non-contact technique. We here review the main contemporary technologies for intraoperative CBF monitoring and their current and potential future applications in neurosurgery.

Positional cranial deformation in children: A plea for the efficacy of the cranial helmet in children.

BACKGROUND: Cranial deformations have historically aroused the interest of people worldwide. One of the more debated points about positional plagiocephaly is the choice of the treatment. In this article, the senior author (CM) shares his experience on almost 30 years of use of the helmet molding therapy in children with deformation plagiocephaly. METHODS AND POPULATION: We retrospectively and systematically reviewed the cases of 2188 patients (75% males and 25% females) presenting positional head deformity and treated between 1991 and 2013 with a cranial helmet. To assess the effectiveness of the helmet, we compared the cranial index in bilateral plagiocephaly and the Cranial Diagonals Difference (CDD) in unilateral plagiocephaly at the beginning and at the end of the treatment. RESULTS: The cranial indexes ranged between 94.4% and 124.2% before the treatment and decreased significantly between 86.8% and 121.4% after the treatment (P<0.01). The CDD ranged between 0.3 cm and 4.5 cm with an average of 1.50±0.54 cm before the treatment and decreased significantly between 0.1 cm and 2.5 cm with an average of 0.72±0.37 cm after the treatment (P<0.01). For unilateral plagiocephaly, at the beginning of the treatment, 2.5% children presented a mild plagiocephaly, 19.6% a moderate plagiocephaly and 77.9% a severe plagiocephaly. At the end of the treatment, the deformation was classified as mild in 40.2% children, moderate in 44.3% children and severe in 15.5% children with significantly less children in the most severe subgroups (P<0.01) Facial symmetry pre-existed before the treatment in 13.7% of children. This rate was significantly increased at the end of the treatment to 66.7% (P<0.01). In only 8 cases (0.2%), the helmet therapy did not allow to obtain correct clinical results and a surgical posterior cranial remodeling was performed. CONCLUSIONS: The results observed in this series confirms that cranial helmet is a simple and well tolerated alternative which bring satisfying results. Its success implies a good collaboration with parents and a management both by orthoptist, physiotherapist and doctor. Nevertheless, it remains many controversies in the literature concerning in particular long-term cosmetic and functional outcomes. A long-term multicentric prospective study could enable to remove doubts.

Optimization of high-grade glioma resection using 5-ALA fluorescence-guided surgery: A literature review and practical recommendations from the neuro-oncology club of the French society of neurosurgery.

BACKGROUND: When feasible, the surgical resection is the standard first step of the management of high-grade gliomas. 5-ALA fluorescence-guided-surgery (5-ALA-FGS) was developed to ease the intra-operative delineation of tumor borders in order to maximize the extent of resection. METHODS: A Medline electronic database search was conducted. English language studies from January 1998 until July 2018 were included, following the PRISMA guidelines. RESULTS: 5-ALA can be considered as a specific tool for the detection of tumor remnant but has a weaker sensibility (level 2). 5-ALA-FGS is associated with a significant increase in the rate of gross total resection reaching more than 90% in some series (level 1). Consistently, 5-ALAFGS improves progression-free survival (level 1). However, the gain in overall survival is more debated. The use of 5-ALA-FGS in eloquent areas is feasible but requires simultaneous intraoperative electrophysiologic functional brain monitoring to precisely locate and preserve eloquent areas (level 2). 5-ALA is usable during the first resection of a glioma but also at recurrence (level 2). From a practical standpoint, 5-ALA is orally administered 3 hours before the induction of anesthesia, the recommended dose being 20 mg/kg. Intra-operatively, the procedure is performed as usually with a central debulking and a peripheral dissection during which the surgeon switches from white to blue light. Provided that some precautions are observed, the technique does not expose the patient to particular complications. CONCLUSION: Although 5-ALA-FGS contributes to improve gliomas management, there are still some limitations. Future methods will be developed to improve the sensibility of 5-ALA-FGS.

Is fluorescence-guided surgery with 5-ala in eloquent areas for malignant gliomas a reasonable and useful technique?

INTRODUCTION: High-grade gliomas surgery in eloquent areas must achieve two pivotal aims: oncological efficacy and preservation of unimpaired neurological functions or improvement of impaired neurological functions. Here, we evaluated the safety and the usefulness of 5-ALA fluorescence-guided surgery in eloquent areas. MATERIAL AND METHODS: Single center, retrospective and consecutive series of adult patients operated on for a supratentorial glioblastoma between November 2012 and November 2015. RESULTS: Fifty-one patients with a glioblastoma located within an eloquent area were included: 24 patients operated on with 5-ALA (5-ALA group), and 27 patients operated on under white light (control group). Preoperative motor and language deficits were similar in the 5-ALA group (50%, 37.5%) as in the control group (59.3%, 55.6%) (P=0.510; P=0.200). Three-month postoperative motor and language deficits rates were similar in the 5-ALA group (12.5%, 12.5%) as in the control group (29.6%, 14.8%) (P=0.180; P=0.990). The extent of resection did not significantly vary between groups (P=0.280). The overall survival did not significantly vary between groups (P=0.080) but the progression-free survival was significantly higher in the 5-ALA group than in the control group (P=0.020). The 12-month progression-free survival was significantly higher in 5-ALA group (60%) than in control group (21%; P=0.006). In multivariate analysis, the 5-ALA was an independent prognostic factor associated with progression-free survival (P=0.030). CONCLUSION: 5-ALA fluorescence-guided surgery for glioblastoma located in eloquent areas is effective to improve progression-free survival. To preserve functional outcomes, it requires the routine use of intraoperative functional mapping to respect functional boundaries.