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Biomedical subjects

Daniel K Resnick

Publications and source records attributed to Daniel K Resnick.

42 records · Page 3Linked to original sources

Anterior cervicothoracic junction corpectomy and plate fixation without sternotomy.

OBJECT: Exposure of the lower cervical and upper thoracic spinal regions through a cervical incision without sternotomy has been described in cases of anterior decompression and methylmethacrylate vertebral body reconstruction. The use of anterior instrumentation and structural bone grafts in this procedure has not been well described. METHODS: Twenty-one patients underwent anterior cervicothoracic decompression, fusion, and fixation via a low cervical approach. Eight of these patients underwent lower cervical or upper thoracic corpectomy (C7-T4) through the cervical incision. The decompressive procedure was followed by placement of an allograft bone strut and an anterior locking plate system. No patient developed new neurological deficit related to the spinal cord or exiting nerve roots. Three of four patients with preoperative neurological deficits improved dramatically. Two patients developed recurrent laryngeal nerve palsy, of which one was permanent. There was one case of instrumentation-related failure, and two patients developed a superficial wound infection related to a posterior incision made as part of a 360 degrees fusion. Patients were followed for a mean of 18.5 months (range 2-30 months). Two patients died (of metastatic cancer, and a motor vehicle accident, respectively) during the follow-up period. CONCLUSIONS: Anterior decompression, fusion, and fixation is feasible via a cervical incision. This procedural approach spares the patient the morbidity associated with sternotomy or the lateral extracavitary approach. A thorough preoperative assessment of mediastinal anatomy is essential for the safe execution of these procedures.

Aged↗

C1-C2 pedicle screw fixation with rigid cantilever beam construct: case report and technical note.

OBJECTIVE AND IMPORTANCE: Transarticular screw fixation of the C1-C2 complex provides immediate rigid fixation of the unstable spine. The technique is not feasible in a certain proportion of patients because of the position of the vertebral artery or the patient's body habitus. CLINICAL PRESENTATION: The authors describe a rigid screw technique for the surgical treatment of a woman who was excluded as a candidate for C1-C2 transarticular screw fixation. TECHNIQUE: C1-C2 pedicle screw fixation was achieved using a fixed moment arm cantilever beam system. This system provided immediate rigid fixation of the C1-C2 complex in a patient who was not a candidate for transarticular screw fixation. CONCLUSION: This technique is technically more forgiving than posterior transarticular screw fixation and may be applied to a broader spectrum of patients.

Bone Screws↗

Measuring the axial rotation of lumbar vertebrae in vivo with MR imaging.

BACKGROUND AND PURPOSE: Flexion-extension radiography is neither sensitive nor specific in the diagnosis of degenerative spinal instability, a presumed cause of back pain and an indication for spinal fusion. We tested the hypothesis that with MR imaging and a device to rotate the torso, axial rotations of lumbar vertebrae can be measured with sufficient accuracy and that significantly different rotations can be detected between lumbar segments with degenerated disks and those with normal disks. METHODS: We studied five volunteers without back pain (group 1), five patients who underwent MR imaging because of back pain but were not considered candidates for fusion (group 2), and five patients in whom diskography identified one or more disks with concordant pain (group 3). Each participant was placed on a specially built table that provided separate supports for the torso and for the hips and legs. Series of sagittal images were acquired with a T2-weighted fast spin-echo sequence, with the torso rotated clockwise and then counterclockwise. The amount of rotation was calculated from axial images with use of an automated program. RESULTS: In the five volunteers, rotations of the lumbar motion segments varied between -1.8 degrees and 5.7 degrees, with an average of 0.8 degrees. The abnormal disks in five patients in group 2 rotated from -0.9 degrees to 5.6 degrees, with an average of 3.2 degrees. In group 3, the disks in which concordant pain was elicited rotated from 0.8 degrees to 4.4 degrees, with an average of 2.2 degrees. Difference in rotation between abnormal and normal disks was statistically significant. CONCLUSION: Measurements of rotations of lumbar vertebrae with MR imaging may have value for determining levels that move abnormally in axial rotation.

Adult↗

Cervical laminoplasty.

Laminoplasty was developed to treat multilevel pathology of the cervical spine, namely ossification of the posterior longitudinal ligament and cervical spondylotic myelopathy. Laminoplasty was popularized in the 1980s, and since then many variations on the theme have been developed. All are similar in that they expand the cervical canal while leaving the protective dorsal elements in place. Advocates claim that this prevents the formation of the "postlaminectomy" membrane, maintains spinal alignment, and should aid in maintaining cervical range of motion. The aforementioned are all potential shortcomings of laminectomy or laminectomy and fusion. The procedure has proven to be essentially equal to other cervical decompressive procedures in the neutral or lordotic spine, and outcome has been shown to be durable.

Cervical Vertebrae↗