Cerebrospinal Fluid and Hydrocephalus: Physiology, Diagnosis, and Treatment.

BACKGROUND: Cerebrospinal fluid (CSF) is found around and inside the brain and vertebral column. CSF plays a crucial role in the protection and homeostasis of neural tissue. METHODS: Key points on the physiology of CSF as well as the diagnostic and treatment options for hydrocephalus are discussed. RESULTS: Understanding the fundamentals of the production, absorption, dynamics, and pathophysiology of CSF is crucial for addressing hydrocephalus. Shunts and endoscopic third ventriculostomy have changed the therapeutic landscape of hydrocephalus. CONCLUSIONS: The treatment of hydrocephalus in adults and children represents a large part of everyday practice for the neurologist, both in benign cases and cancer-related diagnoses.

Robotics in Neurosurgery: Evolution, Current Challenges, and Compromises.

BACKGROUND: Advances in technology have pushed the boundaries of neurosurgery. Surgeons play a major role in the neurosurgical field, but robotic systems challenge the current status quo. Robotic-assisted surgery has revolutionized several surgical fields, yet robotic-assisted neurosurgery is limited by available technology. METHODS: The literature on the current robotic systems in neurosurgery and the challenges and compromises of robotic design are reviewed and discussed. RESULTS: Several robotic systems are currently in use, but the application of these systems is limited in the field of neurosurgery. Most robotic systems are suited to assist in stereotactic procedures. Current research and development teams focus on robotic-assisted microsurgery and minimally invasive surgery. The tasks of miniaturizing the current tools and maximizing control challenge manufacturers and hinder progress. Furthermore, loss of haptic feedback, proprioception, and visualization increase the time it takes for users to master robotic systems. CONCLUSIONS: Robotic-assisted surgery is a promising field in neurosurgery, but improvements and breakthroughs in minimally invasive and endoscopic robotic-assisted surgical systems must occur before robotic assistance becomes commonplace in the neurosurgical field.

Spinal neoplastic instability: biomechanics and current management options.

BACKGROUND: Often the spine is afflicted from primary or metastatic neoplastic disease, which can lead to instability. Instability can cause deformity, pain, and spinal cord compression and is an indication for surgery. Although overt instability is uniformly agreed upon, it is sometimes difficult for specialists to agree on subtle degrees of instability due to lack of objective criteria. METHODS: In this article, treatment options and the spine instability neoplastic system are discussed and the neoplastic instability literature is reviewed. RESULTS: The Spinal Instability Neoplastic Score helps specialists determine whether instability is present and when surgery may be indicated. However, other parameters such as spinal cord compression and extent of disease dictate whether surgery is the most appropriate option. A wide range of fusion techniques exists, each one tailored to the location of the lesion and goals for surgery. CONCLUSIONS: To optimize results, expert knowledge on the techniques and patient selection is of importance. Furthermore, a multidisciplinary approach is required because treatment of neoplastic disease is multimodal.

Underwater versus Closed Drainage System for Surgical Treatment of Chronic Subdural Hematoma.

OBJECTIVES: Chronic subdural hematoma (CDH) is a prevalent condition in neurosurgery. Standard care includes surgical evacuation with drainage of residual subdural cavity. We hypothesized that effective and timely drainage of subdural space may improve clinical and radiological outcomes. This study was conducted to compare the effectiveness of standard closed drainage and underwater drainage. METHODS: Medical data of 300 surgically treated chronic subdural hematoma CDH patients were retrospectively collected and analyzed. The patients were divided into two 2 groups: Group I with underwater drainage, and Group II with closed drainage. Groups were compared in terms of gender, age, complication rates, recurrence rates, seizure rates, and length of hospital stay. RESULTS: Underwater drainage was found superior to closed system by all clinical and radiographic parameters. The recurrence rate was significantly lower in Group I (2%) compared to with Group II (10%). Subdural empyema was observed in 10 patients in Group II and none in Group I. The seizure rate was higher in Group II (18%) compared to with Group I (5%). Postoperative pneumocephalus rates was were 20% in Group I and 54% in Group II. The length of hospital stay was 6±2.6 days in Group I and 8.9±6.1 days in Group II. The length of intensive care unit (ICU) stay was 0.6±1.12 days in Group I and 2.7±5 days in Group II. A minority (5%) of the patients in Group II required reoperation due to recurrence. CONCLUSIONS: The use of underwater system significantly the reduces the rates of pneumocephalus, seizures, infection, and recurrence. Additional benefits are shorter intensive care unit ICU and total hospital stays.

Mini-open lateral retroperitoneal lumbar spine approach using psoas muscle retraction technique. Technical report and initial results on six patients.

PURPOSE: The main aim of this paper was to report reproducible method of lumbar spine access via a lateral retroperitoneal route. METHODS: The authors conducted a retrospective analysis of the technical aspects and clinical outcomes of six patients who underwent lateral multilevel retroperitoneal interbody fusion with psoas muscle retraction technique. The main goal was to develop a simple and reproducible technique to avoid injury to the lumbar plexus. RESULTS: Six patients were operated at 15 levels using psoas muscle retraction technique. All patients reported improvement in back pain and radiculopathy after the surgery. The only procedure-related transient complication was weakness and pain on hip flexion that resolved by the first follow-up visit. CONCLUSIONS: Psoas retraction technique is a reliable technique for lateral access to the lumbar spine and may avoid some of the complications related to traditional minimally invasive transpsoas approach.

Safety and Efficacy of Posterior Upper Rib Excision and Decompression Technique for Surgical Treatment of Neurogenic Thoracic Outlet Syndrome.

BACKGROUND: There are several approaches used for surgical treatment of neurogenic thoracic outlet syndrome (n-TOS). The posterior upper rib excision and decompression technique is a novel technique that was developed and used by the author for the past 8 years. The purpose of this paper is to report clinical outcomes of patients treated with this approach. METHODS: All patients with n-TOS operated by single surgeon from 2015 to 2023 were retrospectively analyzed. Demographic, clinical, radiologic, surgical, and postoperative data were collected and reported with emphasis on efficacy and complications. The surgical success was evaluated subjectively as excellent, good, fair, poor, and bad. Radiologic data were analyzed to assess the extent of accessory/first rib removal. RESULTS: Eighty procedures were performed in 61 patients with a mean follow-up of 1153 (87-3048) days. The majority (60.7%) of patients were women, with 39.3% being men. In 11 cases (18%) causative factor was bone abnormality. Two patients were previously operated at another centers (3.3%). Total mean subjective improvement rate was 91.5%. More than half (55) of the patients reported "excellent" (>75%) and 6 "good" improvements (50%-75%); no fair, poor, and worse outcomes were reported. Patients reporting "good" outcome had statistically significant shorter follow-ups than the "excellent" group (P < 0.001). Complications included pleural opening, Horner syndrome, and apical hematoma, none of which were permanent. CONCLUSIONS: The posterior upper rib excision and decompression approach provides excellent clinical outcomes in patients with n-TOS. It allows better intraoperative visualization and removal of the first rib and full decompression of the neurovascular bundle.

Inter-Specimen Analysis of Diverse Finite Element Models of the Lumbar Spine.

Over the past few decades, there has been a growing popularity in utilizing finite element analysis to study the spine. However, most current studies tend to use one specimen for their models. This research aimed to validate multiple finite element models by comparing them with data from in vivo experiments and other existing finite element studies. Additionally, this study sought to analyze the data based on the gender and age of the specimens. For this study, eight lumbar spine (L2-L5) finite element models were developed. These models were then subjected to finite element analysis to simulate the six fundamental motions. CT scans were obtained from a total of eight individuals, four males and four females, ranging in age from forty-four (44) to seventy-three (73) years old. The CT scans were preprocessed and used to construct finite element models that accurately emulated the motions of flexion, extension, lateral bending, and axial rotation. Preloads and moments were applied to the models to replicate physiological loading conditions. This study focused on analyzing various parameters such as vertebral rotation, facet forces, and intradiscal pressure in all loading directions. The obtained data were then compared with the results of other finite element analyses and in vivo experimental measurements found in the existing literature to ensure their validity. This study successfully validated the intervertebral rotation, intradiscal pressure, and facet force results by comparing them with previous research findings. Notably, this study concluded that gender did not have a significant impact on the results. However, the results did highlight the importance of age as a critical variable when modeling the lumbar spine.

Is vertebral augmentation the right choice for cancer patients with painful vertebral compression fractures?

Cancer-related fractures of the spine are different from osteoporotic ones, not only in pathogenesis but also in natural history and treatment. Higher class evidence now supports offering balloon kyphoplasty to a patient with cancer, provided that the pain is significant in intensity, has a positional character, and correlates to the area of the fractured vertebrae. Absence of clinical spinal cord compression and overt instability are paramount. Because of the frequent disruption of the posterior vertebral body cortex in these patients, the procedure should be performed by experienced operators who could also quickly perform an open decompression if cement extravasation occurs. Patients will benefit from vertebral augmentation, even in chronic malignant fractures. A biopsy should be routinely performed and a combination with radiation treatment would be beneficial in most cases.

Comparing effects of kyphoplasty, vertebroplasty, and non-surgical management in a systematic review of randomized and non-randomized controlled studies.

PURPOSE: To determine if differences in safety or efficacy exist between balloon kyphoplasty (BKP), vertebroplasty (VP) and non-surgical management (NSM) for the treatment of osteoporotic vertebral compression fractures (VCFs). METHODS: As of February 1, 2011, a PubMed search (key words: kyphoplasty, vertebroplasty) resulted in 1,587 articles out of which 27 met basic selection criteria (prospective multiple-arm studies with cohorts of ≥ 20 patients). This systematic review adheres to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. RESULTS: Pain reduction in both BKP (-5.07/10 points, P < 0.01) and VP (-4.55/10, P < 0.01) was superior to that for NSM (-2.17/10), while no difference was found between BKP/VP (P = 0.35). Subsequent fractures occurred more frequently in the NSM group (22 %) compared with VP (11 %, P = 0.04) and BKP (11 %, P = 0.01). BKP resulted in greater kyphosis reduction than VP (4.8º vs. 1.7°, P < 0.01). Quality of life (QOL) improvement showed superiority of BKP over VP (P = 0.04), along with a trend for disability improvement (P = 0.08). Cement extravasation was less frequent in the BKP (P = 0.01). Surgical intervention within the first 7 weeks yielded greater pain reduction than VCFs treated later. CONCLUSIONS: BKP/VP provided greater pain relief and fewer subsequent fractures than NSM in osteoporotic VCFs. BKP is marginally favored over VP in disability improvement, and significantly favored in QOL improvement. BKP had a lower risk of cement extravasation and resulted in greater kyphosis correction. Despite this analysis being restricted to Level I and II studies, significant heterogeneity suggests that the current literature is delivering inconsistent messages and further trials are needed to delineate confounding variables.

Aquaporin-4 expression is not elevated in mild hydrocephalus.

BACKGROUND: Aquaporin-4 (aqp-4) is a member of water channel family proteins primarily expressed in the central nervous system. Physiologically it is the main channel providing water transport into the nervous system water compartments and across the blood-brain barrier. Several studies demonstrated its compensatory role in severe hydrocephalus. However, its role is not clear during the initial stages of hydrocephalus. OBJECTIVE: This study was designed to investigate aqp-4 expression in less severe forms of hydrocephalus and to determine its role in disease progression. METHODS: Twenty-five male Wistar-Hannover rats, were distributed into experimental (n = 20) and control (n = 5) groups. Hydrocephalus was induced in the experimental group by injection of 5 µl 25% kaolin suspension into the cisterna magna. Control animals received an injection of 5 µl normal saline. Eight weeks later, the animals were killed by the perfusion-fixation method. Immunohistochemical and Western blot analysis were performed. RESULTS: Ventricular dilatations were noted in all experimental animals. Both groups demonstrated positive immunoreactive signals to aqp-4. Immunohistochemically there were no changes in aqp-4 pattern and expression intensity between experimental and control animals. Similarly, Western blot analysis revealed mean aqp-4 values in experimental and control groups as 0.3436 and 0.3917, respectively, and the difference did not reach statistical significance (p > 0.05). CONCLUSION: Our results indicate that aqp-4 is not up-regulated during the initial stages of hydrocephalus. This implies that aqp-4 may not play a significant role in hydrocephalus compensation until severe ventricular dilatation occurs.

Adult intradural primary spinal cord tumors.

Primary spinal cord tumors represent 4.5% of all central nervous system neoplasms. They are either intradural intramedullary or intradural extramedullary. Intramedullary tumors are predominantly intrinsic gliomas (astrocytomas and ependymomas). Spinal ependymomas can usually be completely removed by separating the tumor from the spinal cord and, when complete, no further therapy is required. Astrocytomas, by contrast, infiltrate the myelon, and therefore surgery is frequently incomplete. Intradural extramedullary tumors are mostly benign (WHO grade 1) and comprise either peripheral nerve sheath tumors (neurofibromas and schwannomas) or meningiomas. Complete resection can be performed on both lesions and is often curative. Radiotherapy is indicated for primary malignant tumors (WHO grade 3 and higher) and for patients in whom surgery is contraindicated. For grade 1 and 2 tumors, the role of radiotherapy is controversial. Chemotherapy is reserved for recurrent primary spinal cord tumors with no other options. However, the lack of clinical trials for these tumors is problematic. Consequently, treatment is similar to that for intracranial histologies. Early recognition of the signs and symptoms of primary spinal cord tumors facilitates early treatment, potentially minimizes neurologic morbidity, and improves outcome. Primary treatment for almost all spinal cord tumors is surgery, with predictors of outcome being preoperative functional status, grade of tumor, and extent of resection.

Surgical Anatomy of the Posterior Intermuscular Approach to the Brachial Plexus.

Background: First rib resection and scalenectomy is a well-established treatment option for thoracic outlet syndrome. The posterior approach is rarely used due to extensive muscle sacrifice resulting in significant procedural morbidity. In this paper, we report the surgical anatomy of modified and less-invasive muscle-sparing posterior approach. Methods: Eleven human cadavers were used in this study. With specific care to preserve muscles' integrity, the brachial plexus was exposed by dissecting through the posterior neck musculature. A muscular triangle was found under the trapezius muscle, which provided direct access to deeper structures. Four anatomical reference points were identified to denote a 3-dimensional space enclosing proximal brachial plexus. Results: A muscular triangle was found under the trapezius muscle in all cadavers. It was bordered infero-medially by rhomboid minor, supero-medially by splenius capitis, and laterally by levator scapula muscles. The inferomedial border (rhomboid) was 55 mm (48-80), superomedial border (splenius capitis) was 60.5 mm (42-89), and the lateral border (levator scapulae) was 99 mm (60-130). A consistent vein was present inside the triangle and could be used as an anatomical landmark. The 4 reference points were C5, T1 intervertebral foramina, transverse tubercle, and scalene tubercle of the first rib. Removal of the first rib could be performed without brachial plexus retraction. The latter was exposed from neural foramina to lateral border of the first rib. Conclusions: The posterior approach provides ample space to for exposure and manipulation with the first rib and proximal brachial plexus.

Risk of intervertebral disc joint puncture during lumbar puncture.

OBJECTIVE: Penetration of intervertebral disc joint during lumbar puncture might be unnoticed during procedure. However, accelerated degeneration of the disc joint is a long-term consequence of inadvertent penetration. In this paper, we aimed to demonstrate and evaluate the risk of disc puncture during standard lumbar puncture. PATIENTS AND METHODS: 50 human cadavers were used in this study. Disc puncture risk was assessed by using worst case scenario model. Lumbar puncture was performed in a standard fashion using midline route at L3-4, L4-5 and L5-S1 levels. The needle was advanced until it hit resistance from the bone. Lateral X-ray was used to visualize the needle position. Needle ended up in two possible locations - posterior vertebral body wall and intervertebral disc space. RESULTS: The probability of puncturing the joint was 20 % for L3-4, 38 % for L4-5, 16 % for L5-S1. Total probability of disc penetration was 25 %. Statistical analysis revealed significantly increased risk for performing LP at L4-5 level in comparison with L5-S1 (p = 0.023). CONCLUSION: Lumbar puncture carries significant risk of intervertebral disc penetration. This complication is not realized during the procedure and lead to accelerated joint degeneration.

Advances in CSF shunt devices and their assessment for the treatment of hydrocephalus.

INTRODUCTION: Hydrocephalus is a neurological disorder caused by excessive accumulation of the cerebrospinal fluid (CSF) in the ventricles of the brain. It can be treated by diverting the extra fluid to different parts of the body using a device called a shunt. This paper reviews different shunt devices that are used for this purpose. AREAS COVERED: Shunts have high failure rates either due to infection or mechanical failure, therefore there is still ongoing work to address these two main handicaps. They require additional devices for performance assessment. Here, the paper also reviews different approaches for assessing shunt limitations. Moreover, future prospects are also discussed. EXPERT OPINION: This study shows that shunt devices still remain an important treatment option for hydrocephalus. However, further efforts are required to design more advanced shunts, to eliminate high failure rates in clinical use. Sophisticated sensor systems that can accurately detect and regulate changes in CSF drainage to optimize drainage for individual needs. Moreover, shunt infection problem is still present despite recent improvements such as antibiotic impregnated catheters.

Endoscopic Endonasal Approach to Giant Pituitary Adenomas: Surgical Outcomes and Review of the Literature.

OBJECTIVE: To present the outcomes of endoscopic endonasal surgery for giant pituitary adenomas and discuss the extent of resection to minimize morbidity and mortality. METHODS: We retrospectively reviewed medical records of 44 patients with giant pituitary adenomas who underwent endoscopic endonasal surgery. Clinical presentation, laboratory results, imaging studies, clinical outcomes, extent of resection, and complications were collected and analyzed. Factors affecting long-term outcome according to surgical technique were identified and analyzed. RESULTS: Radical resection (RR) was defined as either gross total resection or near-total resection (90%-100% of the tumor). There were 28 patients (63.6%) who underwent RR, 10 patients (22.7%) who underwent subtotal resection, and 6 patients (13.6%) who underwent partial resection. Visual improvement was achieved in 27 patients (81.8%). Thirteen patients (72.2%) with pituitary dysfunction had improvement in at least 1 preoperative endocrinological dysfunction. RR rates for dumbbell and multilobular tumors were 44.4% and 28.6%, respectively. Surgical complications were observed in 14 (31.8%) patients. Major vascular injury occurred in 3 patients (6.8%). Mean follow-up period was 38.5 months (range, 1-70 months). No patients with RR had recurrence or residual tumor progression. Ten patients (22.7%) received adjuvant radiation therapy after resection. Two patients were reoperated on for tumor regrowth, and 3 patients (including the 2 patients with tumor regrowth) were lost to follow-up. CONCLUSIONS: Long-term follow-up results and low recurrence rate of tumors indicate that RR is effective to decrease morbidity and mortality.

Overview of vascular complications of pituitary surgery with special emphasis on unexpected abnormality.

Arterial bleeding during transsphenoidal surgery for pituitary adenoma is known complication. This usually happens due to rupture of intracavernous carotid or delayed hemorrhage due to the carotico-cavernous fistula and/or pseudoaneurysm. There is also evidence that cavernous carotid aneurysms may occur with pituitary tumors, yet largest series failed to demonstrate any link between aneurysm formation and pituitary tumors. Usually such an aneurysm rupture results in formation of carotico-cavernous fistula. However, pituitary apoplexy and even epistaxis have been reported. In this paper we present a patient with recurrent pituitary adenoma and cavernous carotid artery aneurysm, which caused significant hemorrhage during the surgery. Although retrospective analysis of MRI disclosed that the patient had the aneurysm before the first surgery, it remained silent until the second operation. Therefore neurosurgeons should be very susceptive to any signal changes on preoperative MR images, especially in recurrent cases, where normal anatomical relations are disturbed by fibrotic tissue. Also, we reviewed the vascular complication of pituitary surgery based on the literature.

Surgically Treated Epilepsy due to Developmental Venous Anomaly of the Brain: Case Report and Review of the Literature.

BACKGROUND: A congenital malformation of the brain vessels, developmental venous anomaly (DVA) is considered a benign lesion, requiring no intervention unless symptomatic. Epilepsy is a well-known clinical manifestation of DVA. Successful surgery for DVA-associated epilepsy with has been sporadically reported in the literature; however, in all published cases, the anomaly was left intact along with the accompanying lesion. Here we present a surgical case of DVA located in the vicinity of the motor cortex causing drug-resistant simple partial epilepsy. CASE DESCRIPTION: A 34-year-old man was referred due to medically intractable simple partial seizures. He was found to have DVA anterior to the motor cortex that was surgically removed. Following the surgical resection, the patient's seizures stopped, and there were no long-term complications of the procedure. CONCLUSIONS: DVA removal can be performed in selected cases, but more studies are needed to assess the complication rate.

U-shaped Dural Flap: A Simple Method for Transcranial Skull Base Defect Repair-Technical Report.

Accidental anterior skull base defects associated with surgery are difficult to treat. There are several methods for the repair, yet postoperative rhinorrhea can occur despite the closure. A 56-year-old female patient was admitted for the treatment of a paraclinoid internal carotid artery aneurysm. The surgery included removal of the anterior clinoid process, unroofing the optic canal, decompressing the optic nerve, and clipping the aneurysm. During the surgery, the planum sphenoidale was accidentally drilled and the nasal cavity exposed. The dural defect was repaired using a U-flap technique. No postoperative cerebrospinal fluid (CSF) rhinorrhea occurred in the patient, and she was discharged on postoperative day 3. On follow-up examination the patient did not have evidence of CSF leakage.

Cranial and spinal injuries in motorcycle accidents: A hospital-based study.

BACKGROUND: Injuries caused by motorcycle accidents have been reported in several studies with an examination from a general trauma point of view. However, to our knowledge, there is no detailed study specific to central nervous system injuries. This research was focused on central nervous system injuries associated with motorcycle accidents. METHODS: The medical records of 540 patients who were admitted to the emergency department between 2008 and 2016 as the result of a motorcycle accident were retrospectively evaluated. Data were collected from electronic medical records, follow-up forms, and radiological images. Information on patient age, gender, type and site of injury, helmet use, alcohol level, Glasgow Coma Scale score on admission, length of stay in the intensive care unit and hospital, neurological status on discharge, and follow-up was collected and analyzed. RESULTS: A total of 486 of 540 patients (90%) were male, 54 (10%) were female, and the mean age was 31+-18 years (range: 2-85 years, median: 25 years). Cranial injuries were detected in 320 cases (59%). The distribution of cranial injuries was: epidural hemorrhage (12.6%), subdural hemorrhage (15.2%), depressed fracture (10.4%), linear fracture (23%), skull base fracture (5.5%), diffuse axonal injury (9.3%), subarachnoid hemorrhage (25.2%), intracerebral hemorrhage (13.5%), and contusion (26.3%). Spinal fractures were detected in 52 cases (9.6%). Twenty-two (4.07%) of the spinal fractures were observed in the cervical region, 10 (1.85%) in the thoracic region, and 20 (3.7%) in the lumbar region. The mean length of stay in the hospital was 8.2+-4 days and 7 days in the intensive care unit. Sixty-eight patients (12.6%) died. Traumatic cranial entities other than linear fracture were associated with an elevated level of mortality. A Glasgow Coma Scale score of 6 or less was associated with significant mortality (68%). CONCLUSION: A detailed report of motorcycle accident-associated central nervous system injuries is provided. The use of protective equipment, such as helmets, significantly reduced the rate of cerebral injury and death.