Endoscopic endonasal approach to the ventral brainstem: anatomical feasibility and surgical limitations.

OBJECTIVE Sporadic cases of endonasal intraaxial brainstem surgery have been reported in the recent literature. The authors endeavored to assess the feasibility and limitations of endonasal endoscopic surgery for approaching lesions in the ventral portion of the brainstem. METHODS Five human cadaveric heads were used to assess the anatomy and to record various measurements. Extended transsphenoidal and transclival approaches were performed. After exposing the brainstem, white matter dissection was attempted through this endoscopic window, and additional key measurements were taken. RESULTS The rostral exposure of the brainstem was limited by the sella. The lateral limits of the exposure were the intracavernous carotid arteries at the level of the sellar floor, the intrapetrous carotid arteries at the level of the petrous apex, and the inferior petrosal sinuses toward the basion. Caudal extension necessitated partial resection of the anterior C-1 arch and the odontoid process. The midline pons and medulla were exposed in all specimens. Trigeminal nerves were barely visible without the use of angled endoscopes. Access to the peritrigeminal safe zone for gaining entry into the brainstem is medially limited by the pyramidal tract, with a mean lateral pyramidal distance (LPD) of 4.8 ± 0.8 mm. The mean interpyramidal distance was 3.6 ± 0.5 mm, and it progressively decreased toward the pontomedullary junction. The corticospinal tracts (CSTs) coursed from deep to superficial in a craniocaudal direction. The small caliber of the medulla with very superficial CSTs left no room for a safe ventral dissection. The mean pontobasilar midline index averaged at 0.44 ± 0.1. CONCLUSIONS Endoscopic endonasal approaches are best suited for pontine intraaxial tumors when they are close to the midline and strictly anterior to the CST, or for exophytic lesions. Approaching the medulla is anatomically feasible, but the superficiality of the eloquent tracts and interposed nerves limit the safe entry zones. Pituitary transposition after sellar opening is necessary to access the mesencephalon.

The rectus capitis lateralis and the condylar triangle: important landmarks in posterior and lateral approaches to the jugular foramen.

OBJECTIVE The rectus capitis lateralis (RCL) is a small posterior cervical muscle that originates from the transverse process of C-1 and inserts onto the jugular process of the occipital bone. The authors describe the RCL and its anatomical relationships, and discuss its utility as a surgical landmark for safe exposure of the jugular foramen in extended or combined skull base approaches. In addition, the condylar triangle is defined as a landmark for localizing the vertebral artery (VA) and occipital condyle. METHODS Four cadaveric heads (8 sides) were used to perform far-lateral, extended far-lateral, combined transmastoid infralabyrinthine transcervical, and combined far-lateral transmastoid infralabyrinthine transcervical approaches to the jugular foramen. On each side, the RCL was dissected, and its musculoskeletal, vascular, and neural relationships were examined. RESULTS The RCL lies directly posterior to the internal jugular vein-only separated by the carotid sheath and in some cases cranial nerve (CN) XI. The occipital artery travels between the RCL and the posterior belly of the digastric muscle, and the VA passes medially to the RCL as it exits the C-1 foramen transversarium and courses posteriorly toward its dural entrance. CNs IX-XI exit the jugular foramen directly anterior to the RCL. To provide a landmark for identification of the occipital condyle and the extradural VA without exposure of the suboccipital triangle, the authors propose and define a condylar triangle that is formed by the RCL anteriorly, the superior oblique posteriorly, and the occipital bone superiorly. CONCLUSIONS The RCL is an important surgical landmark that allows for early identification of the critical neurovascular structures when approaching the jugular foramen, especially in the presence of anatomically displacing tumors. The condylar triangle is a novel and useful landmark for identifying the terminal segment of the hypoglossal canal as well as the superior aspect of the VA at its exit from the C-1 foramen transversarium, without performing a far-lateral exposure.

Posterior Cervical Transfacet Fusion with Facetal Spacer for the Treatment of Single-Level Cervical Radiculopathy: A Randomized, Controlled Prospective Study.

BACKGROUND: Single-level cervical radiculopathy may be treated conservatively with cervical tractions. Posterior cervical transfacet fusion with a facetal spacer is a viable option. The aim of the present study is to compare posterior cervical transfacet fusion with conservative physical treatment in single-level cervical radiculopathy. METHODS: A total of 80 patients were randomized in 2 groups, a surgical group in which patients were given posterior cervical transfacet fusion and a traction group in which patients were treated conservatively with mechanical cervical tractions. Visual analog scale for arm and neck, Neck Disability Index, and Short Form-36 (SF-36) questionnaires were administered preoperatively and after treatment up to 12 months. RESULTS: After treatment, visual analog scale arm scores were greater in traction group (4.7 vs. 1.5 the day after treatment) and at follow-up controls (traction group vs. surgical group: 5.3 vs. 0.6 at 1 month, 3.6 vs. 0.3 at 6 months, 1.8 vs. 0.2 at 12 months). Neck Disability Index scores were lower in the surgical group (surgical group vs. traction group: 4.4 vs. 20.3 at 1 month, 1.3 vs. 10.5 at 6 months). SF-36 scores were greater in the surgical group (surgical group vs. traction group: 96 vs. 70 at 1 month, 96.5 vs. 82.6 at 6 months). Neck disability index and SF-36 scores were superimposable between the groups at 12-month follow-up. No adjacent-segment arthrosis or late complications were reported at 1-year follow-up in the surgical group. CONCLUSIONS: posterior cervical transfacet fusion is a safe and effective procedure to treat single-level cervical radiculopathy.

Disseminated Cerebrospinal Embryonal Tumor in the Adult.

Introduction. According to the 2016 World Health Organization classification of Tumors of the Central Nervous System, the term Primitive Neuroectodermal Tumor has been replaced by the term Embryonal Tumor (ET). We present a case of disseminated cerebrospinal ET presenting in an adult patient. Illustrative Case. A 49-year-old male presenting with low back pain, dysuria, and hypoesthesia of the lower extremities referred to our emergency department. Brain and whole spine contrast-enhanced MRI documented a diffusively disseminated heterogeneous neoplasm with intradural extra- and intramedullary involvement of the cervicothoracic tract and cauda equina. A primary biopsy of the lumbosacral localization was performed through L5 bilateral laminectomy. Histologic diagnosis was Embryonal Tumor Not Otherwise Specified. The patient underwent chemotherapy with postoperative adjuvant alternating Vincristine-Doxorubicin-Ifosfamide (VAI) and Ifosfamide-Etoposide (IE). Discussion. Spinal ETs are exceedingly rare especially when presenting in the adult patient. Neurosurgical and oncologic management is still unclear. When feasible, surgical removal should always be performed to obtain a histologic diagnosis. Postoperative adjuvant therapy might entail both chemo- and radiotherapy; however a consensus on this matter is still lacking.

Delayed Intraparenchymal Hematoma Following Diagnostic Lumbar Puncture.

Lumbar puncture is a safe and commonly performed procedure, with an overall complication rate of 0.1% to 0.5%. Well-known contraindications to lumbar puncture are an intracranial tumor, noncommunicating hydrocephalus, coagulopathy, and ruptured aneurysm with subarachnoid hemorrhage. We report a case of a young man with epilepsy who, after a lumbar puncture performed for research purposes, presented with an intracerebral hematoma and neurological deficits. To the best of our knowledge, post-tap intraparenchymal hematoma is extremely rare and only 1 case has been reported previously. In consideration, all patients undergoing a lumbar puncture should be informed about this possible rare complication, even in the absence of documented hemorrhagic risk factors.

Endoscopic interlaminar approach for intracanal L5-S1 disc herniation: Classification of disc prolapse in relation to learning curve and surgical outcome.

INTRODUCTION: The full endoscopic interlaminar approach (FEILA) is a minimally invasive procedure to treat intracanal lumbar disc herniation not approachable by endoscopic transforaminal access. Disc prolapses have been classified into three categories according to their position and passing nerve root displacement: (i) type A, in which the nerve root is displaced medially; (ii) type B, in which the nerve root is displaced laterally; and (iii) type C, in which the nerve root is ventrally displaced. We focused on the FEILA technique because it was likely to involve few complications and that provided the advantages of the endoscopic approach. METHODS: We prospectively evaluated 100 consecutive cases of L5-S1 disc herniations operated on with FEILA, including 85 type A cases, 13 type B, and 2 type C. Patients were evaluated at discharge, 3 months, 6 months and 2 years. RESULTS: The operating time varied from 15 to 40 min. The use of drills and burrs was necessary to treat type B disc herniations; thus, it was preferable that these cases were operated on later in the learning curve. After surgery, 90% of neurological deficits improved. The Oswestry Disability Index and visual analog scale leg at last follow-up were 15 and 9, respectively. There were no major complications. There were five cases of recurrence; four of which were treated with same technique and with good results. CONCLUSION: FEILA is a safe procedure for the removal of intracanal L5-S1 disc herniations. The late follow-up confirms the stability of the results. We suggest treating type A prolapse at the beginning of the learning curve and type B herniations after sufficient experience in the use of the burrs has been achieved.

Preparation of nasoseptal flap in trans-sphenoidal surgery using 2-µ thulium laser: technical note.

OBJECTIVE: The purpose of this study was to assess the feasibility of the use of the 2µ-thulium laser in harvesting nasal septal flaps. BACKGROUND DATA: Nasal septal flaps are routinely performed in almost every trans-sphenoidal surgery. The preservation of the arterial vasculature is a mainstay of the procedure. However, the margins of the flap should be sufficiently healthy to regenerate faster, reducing the risk of possible complications. MATERIALS AND METHODS: Eight patients underwent trans-sphenoidal surgery and removal of pituitary adenomas. Reparation of the defect was performed with the positioning of a rotational vascularized nasal-septal flap. The flaps were harvested with the aid of the 2µ-thulium laser. Every patient was then monitored for 6 months through seriated endoscopic endonasal controls. RESULTS: There were no complications related to the use of the laser, either intraoperatively, or postoperatively. The operative timing did not significantly differ from that of traditional techniques. CONCLUSIONS: The use of the 2µ-thulium laser for the harvesting of nasal septal vascularized flaps can be considered safe and feasible. The limited number of treated patients could be considered as the only restriction to the study. A larger study might have uncovered possible instrumentation-related complications, which were not observed in the present study.

Epidural hematoma with detachment of the dural sinuses.

Epidural hematoma (EH) is a neurosurgical emergency that requires early surgical treatment. It is rarely extended bilaterally causing a detachment of the dural sinus or sinuses. The authors present two rare cases of EH with dural sinus detachment and describe how they suspend them. In these cases it is crucial to firmly suspend the dura mater and the dural sinus to the inner skull surface to prevent postoperative rebleeding.

Pleomorphic rhabdomyosarcoma of the cerebellopontine angle in an adult: a review of literature.

Rhabdomyosarcoma (RMS) is a rare and aggressive neoplasm characterised by rapid growth and metastatic invasion. The most frequent localisation is the skeletal musculature of the limbs. The head and the neck are rarely involved. A 50-year-old woman presented to our attention because of a progressively increasing headache, ataxia and vomiting. MRI showed a lesion at the right cerebellopontine angle. Thereafter, the patient was submitted to a piece-meal removal of the neoplasm. Despite the postoperative MRI showed no signs of remnant, 7 months after the surgery, the disease recurred with multiple localisations, and the patient died a few days later. This report is the first description in the literature of a pleomorphic RMS of the cerebellopontine angle. This particular tumour carries a bad prognosis because of the vicinity of nervous structures and of the impossibility of achieving a one-piece resection. More than ever, the adjunctive treatments had to be effective against a potential remnant and in controlling recurrences.

Chordoid meningioma: a retrospective series of seven consecutive cases.

Chordoid meningioma is a rare variant of meningioma characterized by a more aggressive behavior. The present study documents the histological, radiological and clinical features of seven cases treated at the Policlinico Umberto I of Rome from 1999 to 2010. There were five males and two females. Most of the cases were located in the supratentorial space, especially the convexity. Surgical gross total resection was achieved in four cases. Of the remaining three cases, two relapsed and underwent further surgeries and adjuvant treatment. The MIB-1 index had a mean value of 7.5 (range 0.3-25.8). Tumors were composed of epithelioid cells or plump to spindle cells, forming cords, cribriforms or nests, in a mucoid matrix. All tumors showed diffuse positive immunoreactivity to vimentin and epithelial membrane antigen. Surgery is the first line of treatment for this kind of lesion. Gross total resection guaranteed a survival free from recurrences in our series. On the other hand, radiation therapy must be considered in patients submitted to a subtotal resection.

Assessment of the utility of the 2-µ thulium laser in surgical removal of intracranial meningiomas.

BACKGROUND AND OBJECTIVE: Since the 1960s, lasers have been used in neurosurgery for surgical removal of intracranial tumors. Because of its limited penetration (2 mm) through tissues and its wavelength, which is useful in water medium, the 2-µ thulium laser has been applied primarily in urology. Its features are attractive for application under microscope magnification during neurosurgical procedures. The aim of this study was to evaluate the usefulness of the 2-µ thulium laser during microsurgical removal of intracranial meningiomas. MATERIALS AND METHODS: Twenty patients with a diagnosis of intracranial meningiomas were treated with surgical intervention using a 2-µ thulium laser together with bipolar forceps, cavitron ultrasonic surgical aspirator (CUSA) and traditional microdissection instruments. Surgical removal was divided in four phases: (1) dissection from the external structures; (2) coagulation and debulking; (3) dissection from the deep structures; and (4) coagulation and removal of the basal implant. During all these steps, we evaluated the percentage of usage of the 2-µ thulium laser comparing them with bipolar forceps and ultrasonic aspirator and blunt dissection. RESULTS: Thulium laser was used mainly during phases 2 and 4 for 43% and 48.7% of the total removal, respectively. Although also useful during phases 1 and 3, it was only used for 2.2% and 31.3%, respectively: traditional dissection with scissors and forceps was preferred. CONCLUSIONS: Thulium laser seems to be a useful aid in the surgery of intracranial meningiomas, especially to debulk, shrink, and coagulate the mass and the basal implant.