Intraneural Hematoma: A Proposed Anatomic Classification with Potential Treatment Implications.

Intraneural hematoma is a rare entity with fewer than 20 cases reported in the literature. There is no consensus on surgical treatment due to its rarity. We present a novel classification for intraneural hematomas based on a review of the literature and illustrated by 4 cases that were treated in our 3 centers. This classification system localizes the hematoma to the different connective tissue layers that compose the nerve: the paraneurium, epineurium, and perineurium. We believe that this classification has consequences for surgical treatment and can form the foundation for future research into the natural history of these types of lesions.

Clock face model applied to tibial intraneural ganglia in the popliteal fossa.

BACKGROUND: Tibial intraneural ganglia occurring in the popliteal fossa are often misdiagnosed because of their relative rarity. Their joint connection is typically not recognized and therefore not treated, leading to recurrence. STUDY DESIGN: This is a retrospective clinical study. MATERIALS AND METHODS: Magnetic resonance images (MRIs) of six patients with confirmed tibial intraneural ganglia arising from the superior tibiofibular joint were analyzed and were compared to ten individuals with normal tibial nerves who were imaged with MRI. All studies were interpreted as left-sided. A previously designed clock face model introduced for peroneal intraneural ganglia was used to describe the superior tibiofibular joint connection (tail sign). A single axial image was sought to determine the normal anatomic and pathologic relationships of the tibial nerve and tibial articular branch to the superior tibiofibular joint. RESULTS: In all patients with intraneural ganglia, a single conventional axial image at the mid-fibular head level could reliably demonstrate: (1) intraneural cyst within the articular branch at the superior tibiofibular joint connection (tail sign) between 8 and 9 o'clock and intraneural cyst within the tibial nerve, (2) the central location of the tibial nerve posterior to the tibia, and (3) popliteus muscle denervation changes and atrophy (popliteus sign). CONCLUSIONS: This technique can provide radiologists and surgeons with rapid and reproducible information for diagnosis and treatment planning of tibial intraneural ganglia. Similar to its use with the clock face model in peroneal intraneural ganglia, a standard axial image at the mid-fibular head level can be used to interpret key features of tibial intraneural ganglia and identify the joint connection. Improved identification of the presence of a joint connection will change the therapeutic approach of this pathology and reduce cyst recurrences.

Erythropoietin as a neuroprotective agent in traumatic brain injury Review.

BACKGROUND: In the United States, TBI remains a major cause of morbidity and mortality in children and young adults. A total of 1.5 million Americans experience head trauma every year, and the yearly economic cost of this exceeds $56 billion. The magnitude of this problem has generated a great deal of interest in elucidating the complex molecular mechanism underlying cell death and dysfunction after TBI and in the development of neuroprotective agents that will reduce morbidity and mortality. METHODS: A review of recent literature on EPO, TBI, and apoptosis is conducted with analysis of pathophysiologic mechanisms of TBI. In addition, animal experiments and clinical trials pertaining to mechanisms of cell death in TBI and EPO as a neuroprotective agent are reviewed. CONCLUSION: The literature and evidence for EPO as a potent inhibitor of apoptosis and promising therapeutic agent in a variety of neurological insults, including trauma, are mounting. With the recent interest in clinical trials of EPO in human stroke, it is both timely and prudent to consider the use of this pharmaceutical avenue in TBI in man.

Hemorrhagic complications of external ventricular drainage.

OBJECTIVE: Despite the widespread use of external ventricular drainage (EVD), the frequency of associated hemorrhagic complications remains unclear. This retrospective study examined the frequency of hemorrhagic complications of EVD and attempted to discern associated risk factors. METHODS: Treatment records from 160 patients admitted during a 2.5-year period who required EVD placement were reviewed. Indications for placement of EVD included acute complications of cerebrovascular disease (n = 94), traumatic brain injury (n = 36), primary hydrocephalus (n = 16), and tumor (n = 14). Patients received either a 3.0 or 2.5-mm outer diameter ventricular catheter (n = 82 and 78, respectively). Postinsertion computed tomographic scans were obtained within 24 hours on all patients and were analyzed for any new hemorrhage related to the ventricular catheter. Patient age, sex, catheter type, and dimensions of hemorrhage were also analyzed. RESULTS: The incidence of EVD-related hemorrhage was 33 +/- 0.04%. However, the incidence of detectable change in the clinical neurological examination was 2.5%. A significant proportion of EVD-related hemorrhages were small (<4 cm), punctate, intraparenchymal hematomas. Patients with cerebrovascular disease exhibited an increased incidence (39%) of hemorrhage. The mean volume of intraparenchymal hemorrhage was larger in patients who received the 2.5-mm ventricular catheter, as well as those admitted for cerebrovascular disease. CONCLUSION: Hemorrhagic complications of EVD placement are more common than previously suspected. Admitting diagnosis seems to have an effect on the development of an associated hemorrhage and its size. Catheter gauge has an effect on hematoma volume. Most of the hemorrhages seen on postinsertion computed tomographic scans do not cause detectable changes in the clinical examination.

Cranial surgery with an expanded compact intraoperative magnetic resonance imager. Technical note.

In this article the authors report the implementation of an expanded compact intraoperative magnetic resonance (iMR) imager that is designed to overcome significant limitations of an earlier unit. The PoleStar N20 iMR imager has a stronger magnetic field than its predecessor (0.15 tesla compared with 0.12 tesla), a wider gap between magnet poles, and an ergonomically improved gantry design. The additional time needed in the operating room (OR) for use of iMR imaging and the number of sessions per patient were recorded. Stereotactic accuracy of the integrated navigational tool was assessed using a water-covered phantom. Of the 55 patients who have undergone surgery in the PoleStar N20 device, diagnoses included glioma in 13, meningioma in 12, pituitary adenoma in nine, other skull base lesions in seven, and miscellaneous other diagnoses. The extra time required for use of the system averaged 1.1 hours (range 0.5-2 hours). Imaging sessions averaged 2.3 per surgery (range one-six sessions). Measurement of stereotactic accuracy revealed that T1-weighted images were the most accurate. Thinner slices yielded measurably greater accuracy, although this was of questionable clinical significance (all sequences < or =4 mm had a mean error of < or = 1.8 mm). The position of the phantom in the center compared with the periphery of the magnetic field did not affect accuracy (mean error 0.9 mm for each). The PoleStar N20 appears to make intraoperative neuroimaging with a low-field-strength magnet much more practical than it was with the first-generation device. Greater ease of positioning resulted in a decrease in added time in the OR and encouraged a larger number of imaging sessions.

Diagnostic steps, imaging, and electrophysiology.

The patient with a peripheral nerve tumor can present with a variety of signs and symptoms, including pain, motor weakness, sensory deficit, a palpable mass, and even as an asymptomatic incidental finding. Although most tumors that arise from nerve are solitary tumors associated with a single nerve, they may also be associated with global diseases, such as neurofibromatosis type I (von Recklinghausen's), in which case, there maybe multiple masses involving several nerves. Most peripheral nerve tumors are histologically benign; however, they may experience malignant degeneration, especially in the setting of neurofibromatosis. Treatment in the form of gross total surgical removal is therefore indicated in most nerve tumors for histologic diagnosis as well as for relief of symptoms. The goals of the initial diagnostic steps, imaging and electrophysiology, are to determine baseline clinical neurologic function, define anatomic location and extent of the tumor, and record baseline electromyographic parameters. Once these elements are defined, the surgeon may proceed to the operating room with a level of confidence as to how to approach the lesion and remove it safely. Biopsy of peripheral nerve tumors is to be discouraged over gross total removal, and this can be avoided by proper preoperative diagnostic workup.