Study Design:Cadaver study.Objective:To determine the bone density of lumbar vertebral anatomic subregions. Bone mineral density (BMD) is a major factor in osseous fixation construct strength. The standard region for implant fixation of the spine is the pedicle; however, other regions may be more viable options with higher bone quality.Methods:Using computed tomography images, the spine was digitally isolated by applying a filter for adult bone. The spine model was separated into 5 lumbar vertebrae, followed by segmentation of each vertebra into 7 regions and determination of average Hounsfield units (HU). HU was converted to BMD with calibration phantoms of known BMD.Results:Overall mean BMD in vertebral regions ranged from 172 to 393 mg/cm3 with the highest and lowest BMD in the lamina and vertebral body, respectively. Vertebral regions formed 3 distinct groups (P < .03). The vertebral body and transverse processes represent one group with significantly lower BMD than other regions. Spinous process, pedicles, and superior articular processes represent a second group with moderate BMD. Finally, inferior articular process (IAP) and lamina represent a third group with significantly higher BMD than other regions.Conclusions:Standard lumbar fusion currently uses the vertebral body and pedicles as primary locations for fixation despite their relatively low BMD. Utilization of posterior elements, especially the lamina and IAP, may be advantageous as a supplement to modern constructs or the primary site for fixation, possibly mitigating construct failures due to loosening or pullout.

OBJECTIVEAnterior cervical discectomy and fusion (ACDF) with or without partial uncovertebral joint resection (UVR) and posterior keyhole foraminotomy are established operative procedures to treat cervical disc degeneration and radiculopathy. Studies have demonstrated reliable results with each procedure, but none have compared the change in neuroforaminal area between indirect and direct decompression techniques. The purpose of this study was to determine which cervical decompression method most consistently increases neuroforaminal area and how that area is affected by neck position.METHODSEight human cervical functional spinal units (4 each of C5–6 and C6–7) underwent sequential decompression. Each level received the following surgical treatment: bilateral foraminotomy, ACDF, ACDF + partial UVR, and foraminotomy + ACDF. Multidirectional pure moment flexibility testing combined with 3D C-arm imaging was performed after each procedure to measure the minimum cross-sectional area of each foramen in 3 different neck positions: neutral, flexion, and extension.RESULTSNeuroforaminal area increased significantly with foraminotomy versus intact in all positions. These area measurements did not change in the ACDF group through flexion-extension. A significant decrease in area was observed for ACDF in extension (40 mm2) versus neutral (55 mm2). Foraminotomy + ACDF did not significantly increase area compared with foraminotomy in any position. The UVR procedure did not produce any changes in area through flexion-extension.CONCLUSIONSAll procedures increased neuroforaminal area. Foraminotomy and foraminotomy + ACDF produced the greatest increase in area and also maintained the area in extension more than anterior-only procedures. The UVR procedure did not significantly alter the area compared with ACDF alone. With a stable cervical spine, foraminotomy may be preferable to directly decompress the neuroforamen; however, ACDF continues to play an important role for indirect decompression and decompression of more centrally located herniated discs. These findings pertain to bony stenosis of the neuroforamen and may not apply to soft disc herniation. The key points of this study are as follows. Both ACDF and foraminotomy increase the foraminal space. Foraminotomy was most successful in maintaining these increases during neck motion. Partial UVR was not a significant improvement over ACDF alone. Foraminotomy may be more efficient at decompressing the neuroforamen. Results should be taken into consideration only with stable spines.

Introduction of iodinated contrast into the intact colon is not expected to result in imaging-visible renal excretion of this contrast and is a phenomenon that has only rarely been described. We present a case in which such vicarious renal excretion was misinterpreted as a recto-vesical fistula which resulted in unnecessary delay in the patient's management.

Bone mineral density (BMD) has been identified as a major factor in spine construct strength, with failures resulting in pedicle screw loosening and pullout2. Computed tomography (CT) scans have been shown to effectively measure BMD1,4. Previous research has utilized this linear correlation of CT Hounsfield Units (HU) to BMD in order to determine BMD as a function of anatomic location within cervical vertebrae1; however, the lumbar spine has not yet been reported on. The goal of this study was to describe BMD of anatomical regions within lumbar vertebrae using the correlation between HU and BMD. It was hypothesized that posterior elements of the spine would exhibit significantly different BMD than the vertebral body. This was tested through means comparison of BMD for each anatomical region.

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