• SPINAL CORD SIZE AND SHAPE FOLLOWING CERVICAL LAMINOPLASTY

    PURPOSE: To determine the effect of cervical laminoplasty on the cross-sectional morphology of the spinal cord. METHODS: Cervical laminoplasty with neolamina reconstruction was performed in 40 patients with cervical spondylotic myelopathy from 1992 to 1995. The average age at the time of surgery was 61 years. The average follow-up was 36 months. Spinal cord cross-sectional area and sagittal and coronal cord sizes were measured using an image analysis program pre-operatively, three months and one year postoperatively on axial MRI scans. Interobserver variability was assessed. The data were analyzed using nonparametric statistical tests.
  • CERVICAL CORD NEURAPRAXIA: CLASSIFICATION, PATHOMECHANICS, MORBIDITY, AND MANAGEMENT GUIDELINES

    INTRODUCTION: One hundred ten cases of the transient neurological phenomenon, cervical cord neurapraxia (CCN), are presented. METHOD: The authors established a classification system for CCN, developed a new computerized measurement technique for magnetic resonance (MR) imaging, investigated the relationship of the cervical cord to the canal, and analyzed clinical, x-ray, and MR data. One hundred nine males and one female were included in the study; the average age of the participants was 21 years (range 13-33 years). All episodes occurred during sports participation; 87% occurred while the patient was playing football. Follow-up review lasting an average of 3.3 years was available for 105 patients (95%).
  • CHARACTERISTICS OF UNICORTICAL AND BICORTICAL LATERAL MASS SCREWS IN THE CERIVICAL SPINE

    INTRODUCTION: Lateral mass plating for posterior cervical spine fusion is an effective method for the treatment of traumatic and degenerative instability. The stability of the cervical spine plating system is dependent on a number of factors. One of these factors is the strength that the screw has in terms of bony purchase. The initial description of the technique utilized bicortical screw purchase. The challenge to the surgeon is balancing what is safe versus what is biomechanically sound. The added benefit of bicortical purchase must be weighted against the increased risk of injury to nerve roots and the vertebral artery. The purpose of this study was to analyze the safety, pullout strength and radiographic characteristics of unicortical and bicortical screws within cadaveric specimens and to evaluate the influence of level of training on the positioning of these screws.
  • A META-ANALYSIS OF AUTOGRAFT VERSUS ALLOGRAFT IN ANTERIOR CERVICAL FUSION

    INTRODUCTION. Robinson Smith anterior cervical fusion (ACF) is a common procedure for cervical radiculopathy. Published studies comparing autograft and allograft have not conclusively demonstrated the superiority of either choice of graft. A meta-analysis of published, peer-reviewed journal articles was performed to determine if there is a difference in fusion rate, graft complications, or clinical outcome in patients undergoing anterior cervical fusion using autograft or a log raft. METHODS. A thorough search of the medical literature from 1955 was made using the National Library of Medicine online service, as well as manual searches through the orthopaedic and neurosurgery literature.
  • OBSERVATIONS ON THE EFFECT OF SURGICALLY IMPLANTED METALLIC BULLET FRAGMENTS ON THE SPINAL CORD: AN ANIMAL MODEL

    PURPOSE: There have been many clinical studies regarding bullet injuries to the spine, but very little basic research has been done to evaluate the local effects of bullets exposed to the spinal cord, contamination of the cerebrospinal fluid and systemic absorption. This study was performed with an animal model using three types of bullets in order to answer these questions. METHODS: Three commercially available bullets were studied: uncovered lead core bullet, the copper jacket from a lead core bullet, and the SilvertipĀ® (an aluminum alloy) jacket. 18 New Zealand rabbits underwent implantation of these metallic fragments within the spinal canal. Half were placed in the extradural space and half were placed in the intradural space. The animals in both groups were observed for radiographic changes and serological evidence of heavy metal toxicity for up to 12 months.
  • EFFECT OF AN ANTERIOR CERVICAL LOCKING PLATE ON FUSION RATE FOLLOWING MULTI LEVEL DECOMPRESSION

    INTRODUCTION: The success rate for spine fusion declines as the number of attempted fusion levels increases. Strategies to enhance cervical fusion rates have included halo immobilization, anterior and posterior fusions, as well as anterior instrumentation. The purpose of this study was to evaluate the effectiveness of an anterior cervical locking plate on fusion rates after multi level decompression. METHODS: The results of anterior cervical decompression and fusion with instrumentation of three or more levels were reviewed. Clinical and radiographic results were evaluated. Radiographic fusion was defined as lack of motion on flexion-extension radiographs and bridging trabeculae at each graft-host junction. Radiographs were also reviewed for any evidence of plate instability.
  • BONE-MARROW-PIT OF THE PEDICLE INSIDE OF VERTEBRAL BODY: ITS UTILITY AS ANATOMICAL LANDMARK FOR ANTERIOR APPROACH TO THE CERVICAL SPINAL CANAL

    INTRODUCTION: Vertebral artery laceration by the penetration of the lateral wall of the cervical vertebral body has been known as a serious complication of the anterior approach to the cervical spinal canal. The base of uncinate process has been recommended as an anatomical landmark to designate the location of the lateral corner of the spinal canal, however, it can not become a definitely reliable landmark because it does not locate on the covering roof, i.e. the posterior wall, of the spinal canal. The purpose of this study is to obtain a reliable anatomical landmark in entering the lateral corner of the cervical spinal canal in the anterior approach, definitely avoiding vertebral artery laceration by penetration of the lateral wall of the vertebral body.
  • EFFECTS OF DIFFERENT ORIENTATIONS OF SMITH-ROBINSON ILIAC CREST GRAFTS

    INTRODUCTION: The width of the vertebral body between uncovertebral joints is significantly greater than the depth. The Smith-Robinson graft has a limited width but variable depth when placed in a traditional manner. Rotating the graft 90 degrees in the axial plane may better match the diskectomy site and allow for a larger and possibly stronger graft to be placed. The purpose of this study was to determine if a rotated Smith-Robinson graft is significantly larger and/or stronger than a traditional graft. METHODS: Six embalmed cadaveric cervical spines and matching bilateral iliac crests were dissected and the C5-C6 disc was removed. Beginning 2 cm posterior to the anterior superior iliac spine four sequential Smith-Robinson grafts were taken from each iliac crest allowing for four matched pairs for each cadaver.