Exoscopic microneurosurgery in pediatric brain tumors: an ideal tool for complex and peculiar anatomo-topographic scenarios?

PURPOSE: Since its introduction in the 1950s, the microsurgical paradigm has revolutionized neurosurgery. New technologies have been introduced over the years trying to overcome limits of the classical operating microscope. The recently developed 3D exoscopes represent a potential new paradigm for micro-neurosurgery. We analyzed our own experience with a 4 K-3D exoscope in a series of pediatric brain tumors to verify its advantages and limitations in comparison to the operating microscope and in light of the literature. METHODS: Twenty-five pediatric patients with brain tumors underwent surgery at our Institute; the population has been analyzed and described. A score to evaluate the exoscopes and compare it to the operating microscope was considered and postoperatively applied to each single case. RESULTS: The exoscope appears to be at least comparable to the operating microscope (OM) in all analyzed aspects. In the case of deep-seated or fourth ventricle tumors, the exoscope seems to be superior to the microscope. A surgeon-dependent learning curve is necessary for neurosurgeons to be confident with the exoscope. CONCLUSION: Exoscopes appear to be as safe and effective as operating microscopes in pediatric neuro-oncological surgery. They have some advantages that make them superior to microscopes, particularly regarding surgeon ergonomics and fatigue, visual field qualities, and higher choice of intraoperative viewing angles.

Double Myelomeningocele Repair by Fetal Surgery with a Single Micro-Hysterotomy.

INTRODUCTION: Open spina bifida (OSB) is the most common congenital anomaly of the central nervous system. It is associated with severe neurodevelopmental delay, motor impairment, hydrocephalus, and bowel and bladder dysfunction. In selected cases, intrauterine spina bifida repair has been shown to improve neonatal outcomes. Rarely, the spine can have a double defect compromising two different segments and there is a lack of evidence on the feasibility and benefits of intrauterine repair in these cases. CASE PRESENTATION: We present a case with both cervicothoracic and lumbosacral myelomeningocele, Arnold-Chiari malformation type II and bilateral ventriculomegaly, that was treated successfully at 25 weeks with open micro-neurosurgery. Double myelomeningocele was successfully treated through a single 2-cm micro-hysterotomy, by performing external versions to sequentially expose and repair both defects. Weekly postoperative follow-up showed no progression of ventriculomegaly or complications attributable to the procedure. Preterm rupture of membranes prompted a conventional cesarean delivery at 32 weeks of gestation. Neurodevelopmental outcome at 20 months was within normal ranges, having achieved ambulation without orthopedic support and with no need for ventriculoperitoneal shunting. CONCLUSION: This report demonstrates for the first time the feasibility of double OSB repair through a single 2-cm micro-hysterotomy, suggesting that selected isolated cases of double myelomeningocele could be candidates for fetal intervention. Further prospective studies should be carried out to assess the potential benefit of double OSB intrauterine open repair.

Temporal sylvian fissure arachnoid cyst in children: treatment outcome following microsurgical cyst fenestration with special emphasis on cyst reduction and subdural collection.

OBJECTIVES: Controversy remains regarding surgical managements of sylvian fissure arachnoid cyst (SFAC). This review presents our experience in the microsurgical fenestration of pediatric patients with SFAC to define surgical indication, and risks and benefits with special emphasis on postoperative subdural fluid collection (SDFC) and cyst size reduction. METHODS: Thirty-four children with SFAC who underwent microsurgical cyst fenestration at a single institution over a 10-year period were retrospectively reviewed for their clinical presentation, neuroimaging findings, and postsurgical course. The SFACs were classified by a novel grading system based on the degree of arachnoid cyst extension from the sylvian fissure to the insular cistern shown on MR images: grade 0 - little or no prominence of sylvian fissure, grade I - SFAC confined to the sylvian fissure, grade II - SFAC partially extending to the insular cistern, grade III - SFAC extending to the entire insular cistern. RESULTS: There were 26 males and 8 females. SFAC was present in the left side in 24. Twelve patients presented with cyst rupturing to the subdural space. Cyst grading did not show significant difference compared with rupture status (p > 0.9). All patients underwent microsurgical cyst fenestration. Postoperative SDFC is common but often resolved overtime in two-thirds of the cases with the mean average of 6 months. However, 3 patients had symptomatic postoperative SDFC and needed reoperation shortly after the first operation. Microsurgical cyst fenestrations for SFAC effectively resolved the presenting symptoms and often showed restorations of intracranial structures on follow-up imaging. Cyst resolution or reduction greater than 75% was noted in 61.8% of the patients postoperatively which was noted in a half of the SFAC of children even with age of 11 years or older. During the follow-up, no cyst recurrence or SDFC was noted. Patients with greater surgical reduction of cyst size tended to occur in younger children, and those with lower MR grade. CONCLUSION: Our results showed a high reduction rate of SFAC and brain re-expansion after microsurgical fenestration together with symptomatic improvements regardless the patient's age. Considering the developing CNS during childhood, reductions of a large space-occupying lesion followed by restorations of the structural integrity of the developing brain are very desirable. However, a multi-center cooperative prospective longitudinal study on long-term comparative data of those treated and untreated of neuro-psychological outcome and cyst rupture incidence is needed.

Is surgery effective for treating hypothalamic hamartoma causing isolated central precocious puberty? A systematic review.

The aim of this review was to determine the role of surgery in treating hypothalamic hamartoma (HH) causing isolated central precocious puberty (CPP). Literature review was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Patients with isolated CPP due to HH, managed with surgical resection, were included. We found 33 studies, reporting 103 patients (76 pedunculated, 27 sessile). Patients were considered "cured" if the symptoms of PP had regressed and the hormone profile had normalized after surgery. Indications for surgery included hamartoma deemed surgically resectable (n-12), for the purpose of tissue diagnosis (n-3), partial response/failure of preoperative therapy (n-9), and unable to afford/to avoid long-term medical therapy (n-7). The extent of resection was total (TR) (n-39), near total/subtotal (NTR/STR) (n-20), partial (PR) (n-35), or unspecified (n-9). On follow-up (range: 3 months-16 years), 73.6% (56/76) of patients with pedunculated HH were cured, while 17.1% (13/76) had partial relief. Only 3/27 (11.1%) of patients with sessile HH were cured. All patients with a pedunculated hamartoma who underwent TR (n=36) improved, with 88.88% cured of the symptoms. Surgery had no effect in 17/23 (73.9%) patients with sessile HH who underwent PR. Psychological symptoms improved in 10/11 patients. There was no mortality. Permanent complications, in the form of 3rd nerve palsy, occurred in 3.7% (2/54) of the patients. To conclude, in the current era of availability of GnRH analogs, surgical resection in a subset of patients may be acceptable especially for small pedunculated hamartomas.

Beyond magnification and illumination: preliminary clinical experience with the 4K 3D ORBEYE™ exoscope and a literature review.

BACKGROUND: The operating microscope (OM) is an invaluable tool in neurosurgery but is not without its flaws. The ORBEYE™ (Olympus, Tokyo, Japan) is a 4K 3D exoscope aspiring to offer similar visual fidelity but with superior ergonomics. 2D visualisation was a major limitation of previous models which newer 3D exoscopes attempt to overcome. Here, we present our initial experience using a 4K 3D exoscope for neurosurgical procedures. OBJECTIVE: To evaluate the feasibility of the ORBEYE™ exoscope in performing neurosurgery and review of the literature. METHODS: All patients undergoing neurosurgery performed by a single surgeon, using the ORBEYE™, were assessed. Descriptive statistics and data relating to complications and operative time were recorded and analysed. An anecdotal literature review was performed for the experience of other authors using 4K 3D exoscopes in neurosurgery and compared to our subjective experience with the ORBEYE™. RESULTS: 18 patients underwent surgery using the ORBEYE™. There were no 30-day post-operative complications observed. Our experience and that of other authors suggests that the ORBEYE™ offers comparable visualisation to the traditional OM, with superior ergonomics and an enhanced experience for assistants and observers. CONCLUSION: Neurosurgery can be performed safely and effectively with the ORBEYE™, with improved ergonomics and educational benefit. There appears to be a short learning curve provided one has experience with endoscopic surgery and the use of a foot pedal.

Pediatric brain tumor care in a Sub-Saharan setting: current poise of a precariously loaded dice.

OBJECTIVE: To evaluate the current status of pediatric brain tumor (PBT) care and identify determinants and profiles of survival and school attendance. METHODS: An 8-year institution-based prospective longitudinal study. All cases investigated with neuroimaging and treated were enrolled. Data was analyzed with SPSS (Inc) Chicago IL, USA version 23. Chi Square test, One-way ANOVA and confidence limits were used to evaluate associations at the 95% level of significance. Ethical approval for our study was obtained Health Research Ethics Committee of our hospital. RESULTS: Among 103 patients enrolled, 92 satisfied our study criteria. There were 45 males and 39 females, M: F = 0.8. The mean age was 9.5 ± 2.1 years 95%CI with a range of 7 months to 16 years. The most common symptom was headache for supratentorial lesions (73%) and gait disturbance (80.2%) for infratentorial lesions. More tumors were supratentorial in location 51 (55.4%), 35 (38.1%) were infratentorial and 6 (6.5%) were transtentorial. Craniopharyngiomas (n = 23), medulloblastomas (n = 22) and astrocytomas (n = 15) were the most common tumors. Hemoglobin genotype (AA and AS) had some influence on tumor phenotype FT, P = 0.033. 76 cases were microsurgically resected while 16 patients were treated with radiotherapy alone. The 30-day mortality for operated cases is 7.2 ± 0.7%. Overall 1-year and 5-year survival was 66.7 and 52.3%, respectively. School attendance, performance and outcome varied among treatment subgroups. CONCLUSION: Survival profile in this series suggests some improvement in comparison to previous studies from our region, Hemoglobin genotype profiles may signature paediatric brain tumor phenotypes in our setting.

The prognostic value of histopathology on lingual nerve neurosensory recovery after micro-neurosurgery.

OBJECTIVE: Micro-neurosurgical repair is considered in permanent nerve damage but the outcome is unpredictable. We examined if histopathologic parameters of traumatic neuromas have a prognostic value for recovery in relation to lingual nerve micro-neurosurgery. MATERIALS AND METHODS: Retrospective case study on neurosensory recovery after micro-neurosurgery. Outcome variables were as follows: pain perception, two-point discrimination, and sum score of perception, before and 12 months after micro-neurosurgery. Predictive histopathology variables included size, nerve tissue, and inflammation. Statistics are as follows: logistic and correlation analyses (P < 0.05). RESULTS: Sixty-five patients with lingual nerve damage were included in the study. Improved two-point discrimination was associated with small size of resected tissue (P = 0.0275). No normal appearing distal nerve tissue was associated with improved sum score of perception (P = 0.0185), higher final sum score of perception value (P = 0.0475) and final pain perception (P = 0.0324). Foreign body reaction was associated with no final pain perception (P = 0.0492). CONCLUSIONS: Small size, absence of distal nerve tissue, and no foreign body reaction were associated with improvement of the neurosensory functions. CLINICAL RELEVANCE: Histological parameters of the traumatic neuromas in routine preparation appeared to have some prognostic value for neurosensory functions as improvement of the neurosensory functions was associated with small size of resected tissue, no distal normal appearing nerve tissue, and no foreign body reaction.

Efficacy of low-level laser therapy and microsurgery on neurosensory recovery following inferior alveolar and lingual nerve injuries: A systematic review.

Purpose: This systematic review evaluates the relative effectiveness of low-level laser therapy (LLLT) and microsurgery for neurosensory recovery following sustained iatrogenic injuries to the inferior alveolar nerve (IAN) and lingual nerve (LN) more than 6 months in Oral and Maxillofacial surgery procedures. Methods: Six articles were included. The mean age of microsurgery studies was 41.5 years and that of LLLT studies was 31.5 with female predominance in all studies. The majority of the included studies have been based on both subjective and objective assessments for neurosensory, two investigating microsurgery and four investigating LLLT following a Six-month post-IAN and LN injury. Results: Each modality demonstrated positive outcomes in both subjective and objective assessments of neurosensory function. Notably, LLLT exhibited efficacy even when employed beyond a six-month interval following the initial injury. Early intervention is generally recommended, particularly for microsurgical approaches. Conclusion: LLLT shows exciting promise as a minimally invasive approach for neurosensory rehabilitation even after six months of injury, while microsurgery studies revealed an improvement and the recommendation for early intervention post-nerve injury, the potential of LLLT and optimize its use for neurosensory rehabilitation, additional randomized controlled trials with larger sample sizes, longer follow-up periods, and blinding protocols are necessary.

Computer Assisted Objective Assessment of Micro-Neurosurgical Skills From Intraoperative Videos.

Goal: Conventionally, a surgeon's skill is assessed through visual observation by experts and by tracking patient outcomes. These techniques are very subjective and demands enormous time and effort. Hence, the aim of this study is to construct a framework for automated objective assessment of micro-neurosurgical skill. Methods: A mask region-based convolution neural network (RCNN) is trained to identify and localize instances of surgical instruments from the recorded neurosurgery videos. Then the tool motion and tool handling metrics are computed by tracking the detected instrument locations through time. Microscope adjustment patterns are also investigated via the proposed time based metrics.Results: This study highlights the metrics that could potentially emphasize the variance in expertise between a veteran and a novice. These variations include an expert exhibiting a lower velocity, lower acceleration, lower jerks, reduced path length, higher normalized angular displacement, increased bi-manual handling, shorter idle time and smaller inter tool-tip distances while handling tools accompanied with frequent microscope adjustments and reduced maximum and median intervals between adjustments when compared to a novice. Conclusions: The developed vision based framework has proven to be a reliable method to assess the degree of surgical skill objectively and offer prompt and precise feedback to the neurosurgeons.

Fast instruments and tissues segmentation of micro-neurosurgical scene using high correlative non-local network.

Surgical scene segmentation provides critical information for guidance in micro-neurosurgery. Segmentation of instruments and critical tissues contributes further to robot assisted surgery and surgical evaluation. However, due to the lack of relevant scene segmentation dataset, scale variation and local similarity, micro-neurosurgical segmentation faces many challenges. To address these issues, a high correlative non-local network (HCNNet), is proposed to aggregate multi-scale feature by optimized non-local mechanism. HCNNet adopts two-branch design to generate features of different scale efficiently, while the two branches share common weights in shallow layers. Several short-term dense concatenate (STDC) modules are combined as the backbone to capture both semantic and spatial information. Besides, a high correlative non-local module (HCNM) is designed to guide the upsampling process of the high-level feature by modeling global context generated from the low-level feature. It filters out confused pixels of different classes in the non-local correlation map. Meanwhile, a large segmentation dataset named NeuroSeg is constructed, which contains 15 types of instruments and 3 types of tissues that appear in meningioma resection surgery. The proposed HCNNet achieves the state-of-the-art performance on NeuroSeg, it reaches an inference speed of 54.85 FPS with the highest accuracy of 59.62% mIoU, 74.7% Dice, 70.55% mAcc and 87.12% aAcc.

Diagnosis and Management of Lingual Nerve Injuries.

Injury to the lingual nerve is a well-recognized risk associated with certain routine dental and oral surgical procedures. The assessment and management of a patient with a traumatic lingual nerve neuropathy requires a logical and stepwise approach. The proper application and interpretation of the various neurosensory tests and maneuvers is critical to establishing an accurate diagnosis. The implementation of a surgical or nonsurgical treatment strategy is based not only on the established diagnosis, but also a multitude of variables including patient age, timing and nature of the injury, and the emotional or psychological impact.

Resection of Pontine Cavernoma Through the Anterior Transpetrosal Approach: 2-Dimensional Operative Video.

The pons is the most frequent local for brain stem cavernoma.1 Repeated hemorrhage of brainstem cavernoma is associated with significant and accumulative neurological deficits and thus requires treatment. According to the Swedish Karolinska's group of radiosurgery, "it could not be concluded whether GKRS affects the natural course of a CM. The incidence of radiation-induced complications was approximately seven times higher than that expected."2 Thus, microsurgical removal has become the mainstay of treatment. In our experience, the following details assist in obtaining favorable outcomes and avoiding postoperative complications3,4: (a) the entry into the cavernoma based on thorough knowledge of the microanatomy; (b) the detailed study of the images and the presentation of the cavernoma on or near the brain stem surface; (c) the resection of the live cavernous hemangioma and not the mere removal of the multiple aged organized hematomas; (d) the preservation of the associated venous angioma; (e) the direct and shortest access to the lesion provided by a skull base approach; and (f) the use of the available technology, such as intraoperative neuromonitoring and neuroimaging. We present the case of a 54-yr-old male with recent deterioration in year 2001, past repetitive episodes of gait imbalance, and speech difficulty over a 7-yr period from known pontine cavernoma. The anterior petrosal approach provided superb and direct exposure to the entry at the lateral pons and the cavernoma was totally removed with preservation of the venous angioma. His preoperative neurological deficit rapidly recovered. Patient consented to the procedure and photography. Images at 3:15 from Kadri et al, The anatomical basis for surgical presercation of temporal muscle. J Neurosurg. 2004;100:517-522, used with permission from JNSPG. Image at 3:27 from Al-Mefty O, Operative Atlas of Meningiomas, © LWW, 1997, with permission.

Forty years of clinical excellence at the Dr A Lakshmipathi Neurosurgical Centre and Post-Graduate Institute of Neurological Surgery, Voluntary Health Services (VHS) Hospital.

The Achanta Lakshmipathi Neurosurgical Center (ALNC) and Post Graduate Institute of Neurological Surgery is a private teaching neurosurgical institution located in the VHS (Voluntary Health Services) Hospital Chennai. It has been a leader and trendsetter among the private academic neurosurgical training institutions, and because of its unique legacy, has influenced the progress of Neurosurgery in India. The center was the second neurosurgical Institute to be created by Prof. B Ramamurthi and has trained neurosurgeons in the unique ALNC school of Neurosurgery. The Institute has grown to become a centre of excellence in microsurgery, and spinal surgery and has become a training centre for neurosurgery since 1985. The unique humanitarian aspects of the Voluntary Health Services Hospital helped in bringing the best of Neurosurgery to all strata of society. Forty years after its inception, the ALNC continues its delivery of excellence in clinical neurosurgery and academics.