Diagnosis and management of neurosarcoidosis.

Sarcoidosis is a multisystemic disorder characterised by the presence of multiple noncaseating granulomas. Clinically recognisable nervous system involvement occurs in 5-16% of patients with sarcoidosis. However, the incidence of subclinical neurosarcoidosis may be higher. The following article presents a review of the disease, including its pathophysiology, clinical and radiological characteristics and treatment. Neurosarcoidosis should be included in the differential diagnosis of infectious and noninfectious neurological syndromes.

The spontaneous resorption of herniated cervical discs.

The spontaneous resolution of herniated cervical discs has not been previously well documented. The authors analysed four cases who underwent spontaneous resolution of herniated cervical discs, and all other cases reported in the literature. A complex physiopathologic mechanism that includes the release of basic fibroblast grow factors, endothelial cell proliferation, chemotaxis of inflammatory cells into the disc fragment, foreign body inflammatory reaction, neovascularization and phagocytosis and accounts for the resorption of herniated discs is reviewed.

Hyperacute measurement of intracranial pressure, cerebral perfusion pressure, jugular venous oxygen saturation, and laser Doppler flowmetry, before and during removal of traumatic acute subdural hematoma.

OBJECT: The poor prognosis for traumatic acute subdural hematoma (ASDH) might be due to underlying primary brain damage, ischemia, or both. Ischemia in ASDH is likely caused by increased intracranial pressure (ICP) leading to decreased cerebral perfusion pressure (CPP), but the degree to which these phenomena occur is unknown. The authors report data obtained before and during removal of ASDH in five cases. METHODS: Five patients who underwent emergency evacuation of ASDH were monitored. In all patients, without delaying treatment, a separate surgical team (including the senior author) placed an ICP monitor and a jugular bulb catheter, and in two patients a laser Doppler probe was placed. The ICP prior to removing the bone flap in the five patients was 85, 85, 50, 59, and greater than 40 mm Hg, resulting in CPPs of 25, 3, 25, 56, and less than 50 mm Hg, respectively. Removing the bone flap as well as opening the dura and removing the blood clot produced a significant decrease in ICP and an increase in CPP. Jugular venous oxygen saturation (SjvO2) increased in four patients and decreased in the other during removal of the hematoma. Laser Doppler flow also increased, to 217% and 211% compared with preevacuation flow. CONCLUSIONS: Intracranial pressure is higher than previously suspected and CPP is very low in patients with ASDH. Removal of the bone flap yielded a significant reduction in ICP, which was further decreased by opening the dura and evacuating the hematoma. The SjvO2 as well as laser Doppler flow increased in all patients but one immediately after removal of the hematoma.

Microsurgical anatomy of the Liliequist's membrane and surrounding neurovascular territories.

Since the original description by Liliequist only a few microanatomical studies of the Liliequist membrane have been performed. These studies contain some discrepancies in the description, boundaries, and attachments of the membrane. Using a surgical microscope the authors examined the microsurgical anatomy of Liliequist's membrane and surrounding neurovascular structures in twenty adult brains injected with silicone rubber, with special emphasis given to the analysis of controversial details. This description is intended as an aid for neurosurgeons performing neuroendoscopic procedures.

Spinal cord sarcoidosis: a diagnostic dilemma.

Sarcoidosis is a chronic disorder of unknown etiology characterized by the development of non-caseating granulomas with derangement of the normal tissue architecture. Compromise of the spinal cord is one of the rarest neurologic manifestations of the disease, which may be clinically and radiologically indistinguishable from a spinal cord malignant tumor. However, neurosarcoidosis can be treated with steroids. This study reviews the clinical, radiological, and pathological features of the sarcoid compromise of the spinal cord, emphasizing the difficulties commonly encountered in making a diagnosis.

Safety and feasibility of craniectomy with duraplasty as the initial surgical intervention for severe traumatic brain injury.

BACKGROUND: Decompressive craniectomy has historically served as a salvage procedure to control intracranial pressure after severe traumatic brain injury. We assessed the safety and feasibility of performing craniectomy as the initial surgical intervention. METHODS: Of 29 consecutive patients undergoing emergent decompression for severe traumatic brain injury with horizontal midline shift greater than explained by a removable hematoma, 17 had traditional craniotomy with or without brain resection and 12 underwent craniectomy. RESULTS: The craniectomy group had lower Glasgow Coma Scale scores at surgery (median, 4 vs. 7; p = 0.04) and more severe radiographic injuries (using specific measures). Mortality, Glasgow Outcome Scale scores, Functional Independence Measures, and length of stay in both the acute care setting and the rehabilitation phase were similar between the surgical groups. CONCLUSION: Despite more severe injury severity, patients undergoing initial craniectomy had outcomes similar to those undergoing traditional surgery. A randomized evaluation of the effect of early craniectomy on outcome is warranted.

Bedside invasive monitoring techniques in severe brain-injured patients.

In patients with severe brain injury, brain edema, elevated intracranial pressure, and cerebral ischemia are accountable for a significant morbidity and mortality. New invasive methods of monitoring attempt to foresee the physiopathological mechanisms responsible for the production of secondary brain injuries. The available methods for monitoring severely brain-injured patients, their potential usefulness, advantages, and disadvantages are reviewed.

Spontaneous resolution of a syrinx.

Syrinx are often related to trauma, tumours or abnormalities of the craniocervical junction. Only a few cases of spontaneous resolution have been reported in the literature. The authors present a case of spontaneous resolution of a cervical syrinx, and analyse the possible physiopathological mechanisms leading to resolution. Other similar cases reported in the literature were collected and analysed.

Impaired cerebral mitochondrial function after traumatic brain injury in humans.

OBJECT: Oxygen supply to the brain is often insufficient after traumatic brain injury (TBI), and this results in decreased energy production (adenosine triphosphate [ATP]) with consequent neuronal cell death. It is obviously important to restore oxygen delivery after TBI; however, increasing oxygen delivery alone may not improve ATP production if the patient's mitochondria (the source of ATP) are impaired. Traumatic brain injury has been shown to impair mitochondrial function in animals; however, no human studies have been previously reported. METHODS: Using tissue fractionation procedures, living mitochondria derived from therapeutically removed brain tissue were analyzed in 16 patients with head injury (Glasgow Coma Scale Scores 3-14) and two patients without head injury. Results revealed that in head-injured patients mitochondrial function was impaired, with subsequent decreased ATP production. CONCLUSIONS: Decreased oxygen metabolism due to mitochondrial dysfunction must be taken into account when clinically defining ischemia and interpreting oxygen measurements such as jugular venous oxygen saturation, arteriovenous difference in oxygen content, direct tissue oxygen tension, and cerebral blood oxygen content determined using near-infrared spectroscopy. Restoring mitochondrial function might be as important as maintaining oxygen delivery.

Improvement in mitochondrial dysfunction as a new surrogate efficiency measure for preclinical trials: dose-response and time-window profiles for administration of the calcium channel blocker Ziconotide in experimental brain injury.

OBJECT: Determining the efficacy of a drug used in experimental traumatic brain injury (TBI) requires the use of one or more outcome measures such as decreased mortality or fewer neurological and neuropsychological deficits. Unfortunately, outcomes in these test batteries have a fairly large variability, requiring relatively large sample sizes, and administration of the tests themselves is also very time consuming. The authors previously demonstrated that experimental TBI and human TBI induce mitochondrial dysfunction. Because mitochondrial dysfunction is easy to assess compared with neurobehavioral endpoints, it might prove useful as an outcome measure to establish therapeutic time windows and dose-response curves in preclinical drug testing. This idea was tested in a model of TBI in rats. METHODS: Animals treated with the selective N-type voltage-sensitive calcium channel blocker Ziconotide (also known as SNX-111 and CI-1009) after cortical impact displayed significant improvement in brain mitochondrial function. When a single intravenous bolus injection of 4 mg/kg Ziconotide was given at different time intervals, ranging from 15 minutes before injury to 10 hours after injury, mitochondrial function was improved at all time points, but more so between 2 and 6 hours postinjury. The authors evaluated the effects on mitochondrial function of Ziconotide at different doses by administering 0.5 to 6 mg/kg as a single bolus injection 4 hours after injury, and found 4 mg/kg to be the optimum dose. CONCLUSIONS: The authors established these time-window profiles and dose-response curves on the basis of mitochondrial outcome measures in a total of 42 rats because there were such low standard deviations in these tests. Establishing similar time-window profiles and dose-response curves by using neurobehavioral endpoints would have required using 114 rats in much more elaborate experiments.

Spinal aspergillus osteomyelitis.

Aspergillus species are uncommon etiologic agents of vertebral osteomyelitis. We describe two patients with lumbar vertebral aspergillosis precipitated by the use of corticosteroids and review 39 cases in the literature. The mean age of the population was 40.04 years. There was male predominance (78% of cases), mainly lumbar involvement (53.7%), and monomicrobial nature of infection; 65.8% of the patients had predisposing factors, while 34.1% had none. Back pain (53.6% of cases) was the predominant symptom, while neurological deficits were present in 29.2% of the patients. White blood cell counts were elevated in 12.2% of the patients, and erythrocyte sedimentation rates were >40 mm/h in 39%. The overall recovery rate was 68.3%, and the mortality rate was 26.8%. Although aspergillus osteomyelitis is primarily treated medically, certain cases may require surgical intervention.

Evaluation of expanded polytetrafluoroethylene (ePTFE) versus polydioxanone (PDS) for the repair of dura mater defects.

A comparative animal experimental study was performed to test the potential application of expanded polytetrafluoroethylene (ePTFE) vs. polydioxanone (PDS) as dural substitutes. Sixty male Sprague-Dawley rats underwent a right frontoparietal craniotomy, opening of the dura mater, and a small cortical lesion. The dural defect was covered with a piece of ePTFE or PDS. Animals were sacrificed at 30 days or 90 days. Following decalcification, heads including scalp, skull, and underlying brain were sectioned, stained with hematoxylin-eosin, and histologically analyzed. Dural defects repaired with ePTFE, showed minimal reactive changes and no adhesions to the brain surface. No foreign body type giant cell reaction was seen, and the graft became enclosed in a thin sheet of connective tissue. Dural defects repaired with PDS, showed some giant cell infiltration and ingrowth of collagen fibers. Both substitutes provided satisfactory biological function and biocompatibility. Expanded PTFE advantages included relative suppression of tissue ingrowth, ensheathment by connective tissue, and a high tearing strength. Although both materials show promise for use in dural grafting, further clinical studies are necessary to determine their potential applications as a human dural substitute.

Temperature distribution produced in brain tissue and other media by a radiofrequency hyperthermia generator.

The temperature distribution produced in living brain tissue by a radiofrequency, Neuro N-50, hyperthermia probe was measured as a function of probe temperature, heating duration, and distance from the heating probe by a sensor containing five thermocouples for durations up to 2 min. Brain sections were examined to determine the effects of heating at various temperatures. It was found that a simple theoretical conductive heat transfer model predicted the steady-state temperature distributions quite well. At distances up to 7.4 mm from the heating probe, a heating time of 20 s was sufficient to produce about 90% of the temperature rise measured at 120 s. The equilibrium temperature at any distance from the center of the probe was a linear function of the reciprocal of this distance. The time constant for heating was approximately 3 s at 0. 95 mm from the heating probe and about 10 s at 7.4 mm for brain tissue, while these values are about 5-20 s in egg white. For a given probe size, higher probe temperatures increased the size of the region of cell death. According to the heat transfer model, the diameter of the region of tissue that attains a given temperature is proportional to the diameter of the probe. The use of probe temperatures up to 90 degrees C would enable an increase in the volume of the region of cell death, or the use of a smaller diameter probe to produce a lesion of a given size.

Magnetic resonance imaging of intercranial plasmocytic granuloma.

The objective of this study is to determine characteristic magnetic resonance imaging (MRI) features of intracranial plasmocytic granulomas. Pathological confirmation of three patients with intracranial pathologically confirmed plasmocytic granuloma are presented. Clinical records as well pre- and postgadolinium-enhanced images from each patient are reviewed. The location of the abnormalities is compared with previous reported cases of plasmocytic granulomas, to determine if there is a characteristic finding in this disense. The predominance of this abnormality in the pediatric and young adult patient was striking. On T(1)-weighted MRI, plasmocytic granulomas appear as hypointense lesions, with isointense appearance on T(2) images, and significant, variable patterns of enhancement after the infusion of gadolinium. Typically, the lesion is infiltrating, and causes little mass effect. A dural based lesion, as well as a sellar region abnormality and an infiltrating cortical lesion with little mass effect in the pediatric or young adult age group may lead the observer to suspect the diagnosis of plasmocytic granuloma.

Spinal cord changes after the evacuation of a spinal subdural haematoma.

Spinal subdural haematoma is a rare entity. Only a few cases have been reported, mainly in patients with coagulopathies or bleeding diathesis, and also in patients undergoing anticoagulant therapy following surgery, trauma, or lumbar puncture. Symptoms of spinal cord compression produced by spinal subdural haematoma may progress rapidly causing complete and irreversible deficits. However, rapid diagnosis and surgical intervention can result in a good functional outcome for the patient. We report on a 41-year-old woman with a normal coagulation profile who developed a spinal subdural haematoma after a minor motor vehicle accident. Although initially asymptomatic, she developed a dense quadriparesis over a 36-h period. A magnetic resonance imaging study demonstrated a subdural mass compressing the spinal cord, and at surgery a spinal subdural haematoma was found. She was discharged to an inpatient rehabilitation facility. Follow-up at 1 year showed significant improvement in motor function, but absence of posterior column function. A follow-up magnetic resonance study demonstrated widening of the spinal cord, advanced myelomalacia and a large, central, multi-loculated syrinx.

Treatment of giant cystic craniopharyngiomas.

We report two patients with giant cystic craniopharyngiomas approached transsphenoidally, with continuous cyst drainage through a silastic tube, connecting the cyst with the sphenoid sinus. An innovative technique for fixation of the tube and reconstruction of the sphenoid sinus is presented which consists of the use of a combination of silk, resin and calcium carbonate. Postoperatively, although both patients developed diabetes insipidus, both patients improved neurologically. At follow-up examinations (32 and 48 months), neither patient had migration of the silastic tube, evidence of meningitis, nor cerebrospinal fluid leak. We propose this technique as a surgical alternative for large cystic craniopharyngiomas on which attempt of total resection carries a high risk of severe neurological complications.

Outcome and complications of reconstruction of the thoracolumbar spine for vertebral tumours.

Forty-six patients with progressive neurological deficits or severe pain underwent subtotal vertebrectomy and resection of thoracic and lumbar vertebral tumours. Following subtotal vertebrectomy, 22 spinal segments were reconstructed with titanium mesh cylinders, 13 with allograft struts, 7 with methyl methacrylate, one with autograft bone, and 2 patients underwent spinal reconstruction with miscellaneous materials. In one patient, 40 mm cancellous screws and a titanium mesh cylinder filled with methyl methacrylate were used. Following the reconstruction, 34 patients underwent stabilisation with anterior plates, and 5 patients with posterior rods and pedicle screws. No instrumental fixation was used in 7 patients. Postoperatively, 9 patients who had severe pain but no preoperative neurological deficits remained neurologically intact. Of 33 patients with preoperative incomplete deficit (Frankel grades C and D), 14 improved, 18 were unchanged, and one was worse. Of 3 patients in Frankel grade B, 2 improved to grade C but did not recover ambulation and the third patient remained at Frankel grade B. Other complications included 2 perioperative deaths due to respiratory failure and coagulopathy, one postoperative deterioration, and optic neuropathy in one patient. Backed out screws were seen in 2 patients. Although spinal reconstruction and instrumentation systems allow for immediate stability and mobilisation, a significant perioperative morbidity warrants a careful patient selection.

Use of interactive-intraoperative guidance during vertebrectomy and anterior spinal fusion with instrumental fixation: technical note.

Anterior decompressive procedures for the treatment of vertebral tumors have become increasingly popular in an attempt to improve the quality of life, relieve pain, and preserve or restore neurologic function. However, these procedures carry a significant rate of complications including hardware failure, due in part to technical factors. A computer-assisted system allowing for precise preoperative planning and real-time intraoperative interactive image localization has been implemented for spine instrumentation to optimize anterior instrumental fixation. We discuss our initial clinical experience and application to anterior vertebrectomy, and vertebral reconstruction with anterior instrumental fixation. We believe that computer-assisted spine surgery using infrared-based technology offers the necessary elements to make its use fast, reliable, and intuitive, providing an accurate and safe approach for optimization of spine surgery.