Directional deep brain stimulation in the management of Parkinson's disease: efficacy and constraints-an analytical appraisal.

Deep brain stimulation (DBS) is a widely employed treatment for Parkinson's disease. However, conventional DBS utilizing ring-shaped leads can often result in undesirable side effects by stimulating nearby brain structures, thus limiting its effectiveness. To address this issue, a novel DBS electrode was developed to allow for directional stimulation, avoiding neighboring structures. This literature review aims to analyze the disparities between conventional and directional DBS and discuss the benefits and limitations associated with this innovative electrode design, focusing on the stimulation-induced side effects it can or cannot mitigate. A comprehensive search was conducted in MEDLINE/PubMed, ScienceDirect, and EBSCO databases using the Boolean search criteria: "Deep brain stimulation" AND "Parkinson" AND "Directional." Following the application of inclusion and exclusion criteria, the selected articles were downloaded for full-text reading. Subsequently, the results were organized and analyzed to compose this article. Numerous studies have demonstrated that directional DBS effectively reduces side effects associated with brain stimulation, prevents the stimulation of non-targeted structures, and expands the therapeutic window, among other advantages. However, it has been observed that directional DBS may be more challenging to program and requires higher energy consumption. Furthermore, there is a lack of standardization among different manufacturers of directional DBS electrodes. Various stimulation-induced side effects, including dysarthria, dyskinesia, paresthesias, and symptoms of pyramidal tract activation, have been shown to be mitigated with the use of directional DBS. Moreover, directional electrodes offer a wider therapeutic window and a reduced incidence of undesired effects, requiring the same or lower minimum current for symptom relief compared to conventional DBS. The utilization of directional leads in DBS offers numerous advantages over conventional electrodes without significant drawbacks for patients undergoing directional DBS therapy.

Lacrimal gland pleomorphic adenoma: a narrative review / Adenoma pleomórfico de glândula lacrimal: uma revisão narrativa

ABSTRACT We present a literature review of 57 publications describing this pathology, published from the year 2012. In all these studies patients were reported to depict a slow-growing, motionless mass, which is painless at most times. All cases were managed by total excision, except for one report where adjuvant radiotherapy was applied. Among the several therapeutic strategies, the total tumor resection, preserving the tumor pseudocapsule intact, appears to be a consensus in treating the disease efficiently. Furthermore, fine-needle aspiration biopsy, including the assessment of genetic alterations, has proved to be a valuable tool in the diagnosis of challenging cases. Our literature survey also suggests that an incisional biopsy before the surgery may lead to the pseudocapsule disruption, thus considerably increasing the chances of adenoma recurrence, enabling its malignization. At present, genetics studies indicate that the molecular aberrations involved in the adenoma are similar to those represented in the salivary gland tumor pathogenesis. Further, in the recurrent cases, the pathology becomes difficult to treat and multiple surgeries may be required, occasionally, leading to radical surgery treatment.

RESUMO Uma revisão narrativa da literatura de 57 publicações que descrevem esta patologia, publicada a partir de 2012. Os pacientes têm uma massa de crescimento lento e imóvel, que na maioria das vezes é indolor. Todos os casos foram tratados por excisão total, com exceção de um relatório de radioterapia adjuvante. Entre as estratégias terapêuticas encontradas, a ressecção total do tumor, preservando a pseudocápsula tumoral intacta, parece ser um consenso. Alternativamente, a biópsia por aspiração de agulha fina incluindo a avaliação de alterações genéticas pode representar uma ferramenta valiosa nos casos diagnósticos desafiadores. Uma biópsia incisional antes da cirurgia não é recomendada, pois a ruptura da pseudocápsula aumenta consideravelmente a recorrência do adenoma, permitindo até mesmo sua malignização. Com relação à genética, estudos atuais indicam que as aberrações moleculares envolvidas no adenoma são semelhantes às da patogênese do tumor da glândula salivar. Para casos de recorrência, a patologia torna-se difícil de tratar e múltiplas cirurgias podem ser necessárias, às vezes levando a um tratamento cirúrgico radical.

Lacrimal gland pleomorphic adenoma: a narrative review.

We present a literature review of 57 publications describing this pathology, published from the year 2012. In all these studies patients were reported to depict a slow-growing, motionless mass, which is painless at most times. All cases were managed by total excision, except for one report where adjuvant radiotherapy was applied. Among the several therapeutic strategies, the total tumor resection, preserving the tumor pseudocapsule intact, appears to be a consensus in treating the disease efficiently. Furthermore, fine-needle aspiration biopsy, including the assessment of genetic alterations, has proved to be a valuable tool in the diagnosis of challenging cases. Our literature survey also suggests that an incisional biopsy before the surgery may lead to the pseudocapsule disruption, thus considerably increasing the chances of adenoma recurrence, enabling its malignization. At present, genetics studies indicate that the molecular aberrations involved in the adenoma are similar to those represented in the salivary gland tumor pathogenesis. Further, in the recurrent cases, the pathology becomes difficult to treat and multiple surgeries may be required, occasionally, leading to radical surgery treatment.

Treatment of Hemichoreoathetosis with Arrhythmic Proximal Tremor after Stroke: The Role of Zona Incerta as a Target for Deep Brain Stimulation.

Deep brain stimulation (DBS) of the zona incerta has shown promising results in the reduction of medically refractory movement disorders. However, evidence supporting its efficacy in movement disorders secondary to hemorrhagic stroke or hemichoreoathetosis is limited. We describe a 48-year-old man who developed progressive hemichoreoathetosis with an arrhythmic, proximal tremor in his right arm following a thalamic hemorrhagic stroke. Pharmacological treatment was carried out with no change in the Abnormal Involuntary Movement Scale (AIMS) score after 4 weeks (14). After six sessions of botulinum toxin treatment, a subtle improvement in the AIMS score (13) was registered, but no clinical improvement was noted. The arrhythmic proximal movements were significantly improved after DBS of the zona incerta with a major decrease in the patient's AIMS score (8). The response to DBS occurring after the failure of pharmacological and botulinum toxin treatments suggests that zona incerta DBS may be an alternative for postthalamic hemorrhage movement disorders.

Spinal cord stimulation in the treatment of complex regional pain syndrome type 1: Is trial truly required?

OBJECTIVE: Spinal cord stimulation has been proven highly effective in the treatment of Complex Regional Pain Syndrome (CRPS). The definitive implantation of a neurostimulator is usually preceded by a therapeutic test (trial), which has the purpose of identifying whether the patient would respond positively to neuromodulation or not. The present study aims to analyze the surgical results of spinal cord stimulation in type 1 CRPS patients who have not undergone trial. PATIENTS AND METHODS: From January 2011 to August 2017, 160 patients underwent implantation of spinal cord neurostimulator. Out of that total number of surgeries, 33 patients were unequivocally diagnosed with type 1 Complex Regional Pain Syndrome and selected for this study. The efficacy of the surgical procedure concerning pain improvement was analyzed through the application of the Pain Disability Index and the Visual Analog Pain Scale. RESULTS: The mean sample age was 48.08 years. The majority of the study subjects were female (66.66%). In respect to the Pain Disability Index, a 65% improvement in disability was observed subsequently to the neurostimulator implantation; in addition, the means of the scores for preoperative and postoperative periods were, respectively, 55 ±â€¯8.69 (p < 0.0001) and 18.90 ±â€¯11.58 (p < 0.0001). Regarding the Visual Analogue Scale, the mean pain in the preoperative period was 9.43 ±â€¯0.77 (p < 0.0001), while the mean in postoperative period was 2.86 ±â€¯2.08 (p < 0.0001). Thus, an average reduction of 70% of painful symptoms was observed after the surgical procedure. CONCLUSION: Implantation of a spinal cord neurostimulator presented significant improvement in pain and disability of patients with type 1 CRPS in all cases. These results were obtained following the criteria: 1) patients presenting unequivocal diagnosis of type 1 CRPS; 2) submitted to constant current spinal cord neurostimulator implant; 3) underwent intraoperative tests for precise location of the spinal cord electrode implantation. Therefore, it is possible to suggest that a trial may be unnecessary in that subgroup of patients. Further studies would be required to confirm these findings.

The advances of Deep Brain Stimulation (DBS) for treatment of Parkinson's disease (PD)

Advanced Parkinson's disease (PD) is characterized by the presence of motor fluctuations, various degrees of dyskinesia, and disability with functional impact on daily living and independence. Therapeutic management aims to extend levodopa (L-DOPA) benefit while minimizing motor complications and includes, in selected cases, the implementation of drug infusion and surgical techniques. The concept of deep brain stimulation (DBS) for PD was introduced over 20 years ago, but our understanding of the nuances of this procedure continues to improve. This review aims to demonstrate the advances of DBS in the treatment of PD patients. (AU)

The role of the trigeminocardiac reflex in postoperative hearing function in non-vestibular schwannoma cerebellopontine angle tumors.

The trigeminocardiac reflex (TCR) is a common event during skull base surgery that can lead to intraoperative arterial hypotension and bradycardia. Arterial hypotension associated with TCR can be a negative prognostic factor for postoperative auditory function and ipsilateral tinnitus in patients undergoing surgery for vestibular schwannoma (VS). In this study, the contribution of TCR to postoperative auditory function in non-VS cerebellopontine angle (CPA) tumor surgery was investigated. From a consecutive series of 102 patients with CPA tumors, we studied the occurrence of TCR and its influence on postoperative auditory function in patients with non-VS tumors. Pre- and postoperative auditory function, pre- and intraoperative mean arterial blood pressure, as well as preoperative medication, tumor size, and occurrence of TCR were evaluated. Of the 35 patients evaluated, four developed intraoperative TCR, of whom one was preoperatively deaf. Preoperative functional hearing was detected in 30/35 patients (85.7%): preoperative deafness was documented in one patient in the TCR group and in four patients in the non-TCR group. Of the 30 patients with preoperative functional hearing, 1/3 (33.3%) patients in the TCR group and 23/27 (85.2%) patients in the non-TCR group had functional hearing postoperatively. When patients with large tumors and functional, hearing were considered, only 33.3% of patients in the TCR group and 77.8% of patients in the non-TCR group remained within the same hearing classes following surgical treatment (p=0.1573). TCR may be a negative prognostic factor for postoperative auditory function in patients with large, non-VS CPA tumors.

Intraoperative brainstem auditory evoked potential observations after trigeminocardiac reflex during cerebellopontine angle surgery.

BACKGROUND: The occurrence of trigeminocardiac reflex (TCR) is known to be a negative prognostic factor for hearing preservation in cerebellopontine angle tumor surgery. Our study was conducted to investigate brainstem auditory evoked potential (BAEP) changes after this reflex in cerebellopontine angle tumor surgery and to evaluate their impact on postoperative hearing function. METHODS: Five of 102 consecutive patients had an intraoperative TCR (4.9%) and were retrospectively evaluated for the intraoperative BAEP changes after TCR and postoperative auditory function (7 to 10 d after surgery). One of the 5 patients was preoperatively deaf and therefore excluded from this analysis. RESULTS: Four patients with preoperative functional hearing developed one or more episodes of TCR. Intraoperative BAEP was maintained in 1 patient, whereas in 3 cases an acute intraoperative BAEP deterioration occurred within 2:04 to 3:27 minutes (mean 2:44 min) after TCR with increased wave latency, decreased wave amplitude, and even wave loss. Two patients had deteriorated BAEP waves until the surgical completion and were postoperatively deaf. CONCLUSIONS: Although no direct cause-effect relationship has yet been shown, we suggest TCR as an additional event that may cause BAEP changes. The observed BAEP alterations occurred minutes rather than seconds after the TCR incident leading to both temporary and permanent wave deterioration. This association of BAEP deterioration and TCR occurrence, however, remains yet to be proven justifying further study in the field.

The trigemino-cardiac reflex: an update of the current knowledge.

The trigemino-cardiac reflex (TCR) is clinically defined as the sudden onset of parasympathetic activity, sympathetic hypotension, apnea, or gastric hypermotility during central or peripheral stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported to occur during craniofacial surgery, manipulation of the trigeminal nerve/ganglion and during surgery for lesion in the cerebellopontine angle, cavernous sinus, and the pituitary fossa. Apart from the few clinical reports, the physiologic function of this brainstem reflex has not yet been fully explored. The manifestation of the TCR can vary from bradycardia and hypotension to asystole. From the experimental findings, the TCR represents an expression of a central reflex leading to rapid cerebrovascular vasodilatation generated from excitation of oxygen-sensitive neurons in the rostral ventro-lateral medulla oblongata. By this physiologic response, the systemic and cerebral circulations may be adjusted in a way that augments cerebral perfusion. This review summarizes the current state of knowledge about TCR.

Microsurgical and endoscopic anatomy of the retrosigmoid intradural suprameatal approach to lesions extending from the posterior fossa to the central skull base.

This article evaluates the accessibility of the posterior part of the central skull base via the extended retrosigmoid intradural suprameatal approach. In formaldehyde-fixed specimens, the retrosigmoid intradural suprameatal approach was performed, and the feasibility of reaching central skull base structures was analyzed. Microscopic and endoscopic techniques were used. The main outcome measures were digital films and screenshots, which were analyzed regarding quantitative and qualitative aspects of visual structures. By drilling off the suprameatal tubercle and part of the petrous apex, Meckel's cave may be opened, the trigeminal nerve mobilized, and the tentorium divided. Thus the parasellar area may be exposed and the posterosuperior space of the cavernous sinus approached. Using an endoscope-assisted technique and following cisternal anatomy, the sellar and parasellar region may be explored even if the working space is narrow. The retrosigmoid intradural suprameatal approach provides optimal accessibility to medially located central skull base structures, in particular to the posterior part of the cavernous sinus. Use of the endoscope may remarkably optimize the accessibility.

Auditory rehabilitation after long-term deafness.

OBJECTIVE: The duration of preexisting profound deafness in patients with bilateral retrocochlear lesions is known to correlate negatively to the extent of auditory restoration after auditory brainstem implantation. There is, therefore, a lack of information regarding the potential of the central auditory system to mediate hearing perception after long-term deafness. METHODS: The authors evaluated auditory perception in a case of auditory brainstem implantation after 35 years of deafness. RESULTS: Electrically evoked auditory brainstem potentials could be elicited by both stimulus polarities and were consistent with auditory brainstem origin. Discrimination between temporal and spectral patterns in speech could be achieved. This permitted us to distinguish various voice qualities, especially of familiar speakers in quiet surroundings. CONCLUSION: The potential of the deafferentiated central auditory system to mediate auditory brainstem implant-induced hearing perception even after very long-term deafness has been demonstrated. Those patients with complete dysfunction of Cranial Nerve VIII for a long period may be considered as candidates for auditory brainstem implantation in the future.

Predictive factors for beneficial application of high-frequency electromagnetics for tumour vaporization and coagulation in neurosurgery.

OBJECTIVE: To identify preoperative and intraoperative factors and conditions that predicts the beneficial application of a high-frequency electromagnetic field (EMF) system for tumor vaporization and coagulation. METHODS: One hundred three subsequent patients with brain tumors were microsurgically treated using the EMF system in addition to the standard neurosurgical instrumentarium. A multivariate analysis was performed regarding the usefulness (ineffective/useful/very helpful/essential) of the new technology for tumor vaporization and coagulation, with respect to tumor histology and location, tissue consistency and texture, patients' age and sex. RESULTS: The EMF system could be used effectively during tumor surgery in 83 cases with an essential contribution to the overall success in 14 cases. In the advanced category of effectiveness (very helpful/essential), there was a significant difference between hard and soft tissue consistency (50 of 66 cases vs. 3 of 37 cases). The coagulation function worked well (very helpful/essential) for surface (73 of 103 cases) and spot (46 of 103 cases) coagulation when vessels with a diameter of less than one millimeter were involved. The light-weight bayonet hand piece and long malleable electrodes made the system especially suited for the resection of deep-seated lesions (34 of 52 cases) compared to superficial tumors (19 of 50 cases). The EMF system was less effective than traditional electrosurgical devices in reducing soft glial tumors. Standard methods where also required for coagulation of larger vessels. CONCLUSION: It is possible to identify factors and conditions that predict a beneficial application of high-frequency electromagnetics for tumor vaporization and coagulation. This allows focusing the use of this technology on selective indications.

Combined transconjunctival-eyebrow approach providing minimally invasive access to all orbital quadrants. Technical note.

Surgical approaches to treat orbital disease should provide a good exposure of intraorbital anatomical structures, allow their functional preservation, and provide good cosmetic results. The authors describe a minimally invasive, combined transconjunctival-eyebrow approach to all orbital quadrants in a step-wise manner. The indications, advantages, and limitations of the technique are highlighted. A transconjunctival approach via the postseptal area is described. It allows exposure of the medial, inferior, and lateral parts of the orbit. Depending on the orbital space to be exposed, a lateral or a medial eyebrow incision is then made. The eyebrow and the conjunctival incisions are connected by subperiosteal dissection. This combined access provides exposure to all intraconal muscles and to the superior, medial, lateral, and inferior portions of the optic nerve. The combined transconjunctival-eyebrow approach provides an excellent orbital exposure, with minimal damage to the circumjacent structures. It requires less operative time than other approaches and yields good cosmetic results. Intracranial or intrafacial tumor extension and tumors located purely in the orbital apex are limitations for the use of this technique.

Cystic trochlear nerve schwannoma. Case report.

BACKGROUND: Twenty-six cases of pathologically verified schwannomas of the trochlear nerve have been reported in the literature. Five of them had a large cystic component and a smaller solid portion. Complex skull base approaches have been usually applied for their removal. CASE DESCRIPTION: We report on a rare case of cystic trochlear schwannoma in a 52-year-old female patient. The patient presented with double vision, facial palsy, decreased hearing, hemiparesis on the right side, and severe gait instability. Magnetic resonance imaging revealed a 2.5-cm left-sided extra-axial lesion compressing the brain stem at the lower midbrain and upper pontine level. Total resection was performed via a retrosigmoid craniotomy. After the surgery, the neurological deficit diminished considerably. At 28 months follow-up, her only complaint was mild double vision when walking down the stairs and hypesthesia in the right half of her face. CONCLUSIONS: This case represents a rare pontomesencephalic lesion removed successfully via the simple retrosigmoid route.

Preservation of function in vestibular schwannoma surgery.

The management and surgical technique for microsurgical tumor removal of vestibular schwannomas (acoustic neuroma) with the suboccipital retrosigmoid approach and semi-sitting patient positioning is described. An emphasis is placed on the preservation of auditory and facial nerve function with a stepwise description of the technical and operative nuances, including presurgical evaluation, positioning, anesthesiological and neurophysiological aspects, approach, microsurgical techniques, and postsurgical care.

The impact of petrosal vein preservation on postoperative auditory function in surgery of petrous apex meningiomas.

OBJECTIVE: The importance of preserving the superior petrosal vein has received increasing attention in the surgical treatment of pathologies involving the petrous apex. Recent reports have associated postoperative auditory nerve dysfunction with petrosal vein sacrifice. However, there is no systematic clinical study available thus far focusing on the postoperative auditory function after petrosal vein obliteration. METHODS: In 55 patients with meningiomas involving the petrous apex, pre- and intraoperative findings including petrosal vein sectioning were analyzed retrospectively concerning their impact on postoperative auditory function. RESULTS: The petrosal vein was preserved in 26 (47%) cases. In 27 (49%) cases, this vein was not preserved. Hearing loss occurred in 11% of all cases. In the preserved-vein group, postoperative hearing loss occurred in 3 of 26 (11%) cases and in the sacrificed-vein group in 3 of 27 (11%) cases. CONCLUSION: Sacrifice of the petrosal vein during surgery of petrous apex meningiomas seems not to have an impact on postoperative auditory function.