Object. There is considerable debate among spine surgeons regarding whether fusion should be used to augment decompressive surgery in patients with symptomatic lumbar spinal stenosis involving Grade I degenerative spondylolisthesis. The authors prospectively evaluated the outcomes of patients treated between 2000 and 2002 at two institutions to determine whether fusion improves functional outcome 1 year after surgery. Methods. Patients ranged in age from 50 to 81 years. They presented with degenerative Grade I (3- to 14-mm) spondylolisthesis and lumbar stenosis without gross instability (< 3 mm of motion at the level of subluxation). Those in whom previous surgery had been performed at the level of subluxation were excluded. Each patient completed Oswestry Disability Index (ODI) and Short Form—36 (SF-36) questionnaires preoperatively and at 6 to 12 months postoperatively. Some patients underwent decompression alone (20 cases), whereas others underwent decompression and posterolateral instrumentation-assisted fusion (14 cases), at the treating surgeon's discretion. Baseline demographic data, radiographic features, and ODI and SF-36 scores were similar in both groups. The 1-year fusion rate was 93%. Both forms of surgery independently improved outcome compared with baseline status, based on ODI and SF-36 physical component summary (PCS) results (p < 0.001). Decompression combined with fusion led to an improvement in ODI scores of 27.5 points, whereas decompression alone was associated with a 13.6-point increase (p = 0.02). Analysis of the SF-36 PCS data also demonstrated a significant intergroup difference (p = 0.003). Conclusions. Surgery substantially improved 1-year outcomes based on established outcomes instruments in patients with Grade I spondylolisthesis and stenosis. Fusion was associated with greater functional improvement.

Peritumoral vasogenic brain edema (PVBE) is a common accompaniment of malignant gliomas. It results from microvascular extravasation of plasma fluid and proteins through the interendothelial spaces. Tumor-associated cysts (TACs) are observed more commonly with benign gliomas that are not associated with PVBE. This study investigates the hypothesis that these morphologically distinct epiphenomena of microvascular extravasation are linked by a common pathophysiological mechanism involving vascular endothelial growth/permeability factor (VEG/PF), which has been implicated in vascular leak phenomena including ascites, malignant effusions, and brain edema. Furthermore, VEG/PF has been isolated from cultured glioma cells, and both VEG/PF protein and messenger RNA transcripts are expressed in brain tumor tissue. To further elucidate the relationship of VEG/PF to PVBE and TACs, the authors examined 34 pathological specimens for VEG/PF expression. Nineteen primary low-grade tumors, 11 primary high-grade tumors, and four gliosis controls were immunostained with a polyclonal anti-VEG/PF immunoglobulin G antibody. Magnetic resonance imaging was used to quantitate PVBE and to determine the presence of TACs and tumor enhancement. The study revealed that eight VEG/PF-negative specimens exhibited no significant edema, whereas 26 VEG/PF-positive tumors exhibited either significant PVBE or TACs. Notably, eight of nine benign TACs that were not associated with PVBE immunostained positive for VEG/PF. These data indicate a high degree of correlation between VEG/PF expression by gliomas and the occurrence of PVBE or TACs, irrespective of tumor grade, thus supporting VEG/PF's pivotal role as the common pathophysiological link between these processes.

Metastatic brain tumors are almost always associated with vasogenic brain edema, which in turn plays a pivotal role in the evolution of neurological morbidity associated with these lesions. Attention has recently focused on a group of proteinaceous vascular permeability factors (VPF's) that are capable of inducing angiogenesis and promoting increased capillary permeability. To test the hypothesis that metastatic brain tumors expressing VPF's are associated with peritumoral cerebral edema, a rabbit polyclonal immunoglobulin (Ig) G anti-VPF was used to immunostain pathological specimens of metastatic cerebral tumors obtained from 22 patients who underwent surgery at Yale-New Haven Hospital. Magnetic resonance (MR) imaging was used to correlate VPF staining in tumor tissue with the occurrence of peritumoral brain edema. A histological study of the microvasculature was then conducted by immunostaining the specimens for endothelial cell factor VIII surface antigen, using two gliosis specimens as controls. Results revealed 21 of 22 tumors stained positively for VPF's; the negative-VPF tumor was a melanoma that exhibited no peritumoral edema. Twenty of 22 tumors had MR imaging-evident vasogenic edema. The presence and intensity of VPF immunostaining of microvascular features were noted and compared. Factor VIII staining demonstrated tumor vascularity to be most abundant in VPF-rich regions of tumor. The authors therefore report a high correlation between the presence of VPF's and the occurrence of peritumoral brain edema associated with cerebral metastases.

Gas within the brain parenchyma, known as intracerebral pneumocephalus, has been infrequently reported. Head trauma is the most common cause. A case of intracerebral pneumocephalus resulting from a golf club injury and a review of the literature are presented.

A 31-year-old man who had been shot with a nail gun was unresponsive at presentation, with unequal, nonreactive pupils. The frontal sinus and right frontal pole were debrided emergently. The 6.5-cm nail was left in the midbrain and cerebellar vermis. He extubated himself on day 3, was verbally responsive, and was alert but confused. CT angiogram showed the nail entering the midbrain just above the basilar bifurcation (figure 1), with its initial trajectory just above the circle of Willis (figure 2). One month later, he exhibited slow mentation, dysarthria, and internuclear ophthalmoplegia, but was infection free, fully awake, alert, oriented, and ambulating with assistance.