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Biomedical subjects

Thomas J Errico

Publications and source records attributed to Thomas J Errico.

10 recordsLinked to original sources
PubMed2006

Clinical and radiographically/neuroimaging documented outcome in transforaminal lumbar interbody fusion.

OBJECT: Although transforaminal lumbar interbody fusion (TLIF) is an increasingly popular surgical technique, there are a limited number of studies in which investigators have stratified outcome data with respect to surgical indications or documented radiographically proven and clinical results with respect to disc space height (DSH). The authors conducted a study to evaluate the long-term outcomes after TLIF with respect to surgical indication and radiographic/neuroimaging results. METHODS: Thirty-three consecutive TLIF-treated patients underwent follow-up investigation for a mean of 37 months. Isthmic spondylolysis was present in eight patients, recurrent disc herniation in 14, and degenerative disc disease (DDD) in 11. The operative technique involved the placement of interbody structural allograft, pedicle screw instrumentation, and morcellized autograft in the anterior interbody space and the contralateral intertransverse gutter. Surgery was performed at L4-5 in 16 patients, L5-S1 in 14, L3-4 in two, and both L4-5 and L5-S1 in one patient. Preoperative symptoms were back pain (in 91% of cases), leg pain (in 94%), sensory loss (in 67%), and motor deficits (in 30%). Postoperatively, back pain was improved in 67% of the patients, unchanged in 27%, and worsened in 7%. Leg pain improved in 80% of patients, was unchanged in 10%, and worsened in 10%. Outcome, as measured using the Prolo Functional and Economic Scales, improved from a score of 4.9 to 7. In patients with spondylolysis and recurrent disc herniation outcomes were better than in those with DDD only. There was no correlation of outcome with symptom duration, patient age, or level of surgery. In an independent review of pre- and late postoperative radiographs no significant differences in lordosis angles, Cobb angles, or DSHs were found. Fusion occurred in all cases. CONCLUSIONS: The TLIF procedure was associated with good clinical outcomes and a high fusion rate but no change in the DSH. Patients who present with spondylolysis and recurrent herniations experience better outcome than those with degenerative disease alone.

Adult↗
PubMed2005

Lumbar disc arthroplasty.

Degenerative disc disease is the leading cause of pain and disability in adults in North America, and spinal fusion is the standard treatment. Despite this, it has been discussed among surgeons that (1) spinal fusion deserves reexamination in terms of its long-term consequences and benefits and (2) modern clinical research and development in disc arthroplasty strongly supports its emergence as an alternative. The ability to relieve pain by maintaining motion may be a critical factor in obtaining not only greater pain relief but in preventing adjacent segment degeneration. Early research in arthroplasty devices was promising but cut short. New knowledge in the functional anatomy and biomechanics of the spine has made possible the development of modern arthroplasty devices (eg, Charite Artificial Disc, ProDisc, Maverick device, FlexiCore device) of different constructions and materials (metal-on-plastic, metal-on-metal) and various ranges of motion/mobility that provide a basis for a classification of spinal mode and an assistance in implant selection. Current research also is confronting the critical obstacles of wear and tear and axial compression. Several devices currently are in clinical trials. A detailed review of their characteristics shows the exciting progress of a new treatment era of total disc replacement in spine-lumbar disc arthroplasty.

Arthroplasty, Replacement↗
PubMedDate not supplied

Why a mechanical disc?

Low back pain secondary to degenerative disc disease is an overwhelming and growing problem in the United States and Western countries. Most degenerative disc disease can be treated nonoperatively. There are, however, substantial numbers of patients who have not benefited from exhaustive nonoperative treatments and subsequently seek surgical solutions to their incapacitating back pain. Lumbar fusion for back pain and/or leg pain associated with degenerative disc disease is considered the gold standard by which other treatments are judged. A challenge to spinal fusion for degenerative disc disease is now being offered in the form of the artificial disc. The implantation of an artificial lumbar disc allows for maintenance or restoration of physiologic movement at affected segments. A major long-term complication of spinal fusion is degeneration of a disc adjacent to the fused segments. Theoretically, the maintenance of motion could minimize development of adjacent disc degeneration as seen with spinal fusion. It is interesting to note that fusion of the hip or knee is not considered a primary procedure, but fusion is a primary procedure for the lumbar spine. Four artificial lumbar discs are discussed in this article. Early results are promising in terms of clinical results and movement, but long-term follow-up clinical trials must be done in order to gain an accurate comparison with spinal fusion. Trials are currently ongoing. The clinical results up to now and the potential for maintaining lumbar mobility throughout life warrant continuation of this surgical procedure.

Arthroplasty, Replacement↗
PubMedDate not supplied

Design and evaluation of the FlexiCore metal-on-metal intervertebral disc prosthesis.

BACKGROUND CONTEXT: The technical difficulties associated with the development of an intervertebral disc prosthesis include endurance demands on the device, lack of consensus concerning the biomechanical principles governing the articulation of the spinal joint and the performance of materials available for implantation. PURPOSE: Although biologically based disc prostheses and augmentations may be the endpoint of spinal disc replacements, these devices and associated technologies will still require decades of work in order to achieve fruition. The more immediate solution will require a durable, biocompatible device capable of restoring range of motion. The evaluation of such a device must include failure testing of critical components as well as a series of fatigue experiments under overloaded conditions. STUDY DESIGN/SETTING: Recent literature citing adjacent level degeneration associated with segmental mobilization and a lack of correlation between successful fusion and clinical success has prompted the need for a dynamic intervertebral disc prosthesis. METHODS: Combined with a better understanding of the biomechanics and the prospect of an increasing percentage of more elderly patients, the future of spinal fusion for pain and instability may need to be reexamined. The authors propose a novel metal-on-metal design for an intervertebral device that features a fixed center of rotation, a mechanical torsional limit, a unique feature to allow for the location of the device in a patient-specific manner, and means by which the device may be implanted directly anterior or anterolaterally. RESULTS: Physiological ranges of motion are retained by the prosthesis. In addition, initial and long-term fixations are achieved through spines and bone ingrowth coating. The device comprises a retained ball and socket positioned between two baseplates. The ball and socket joint permits articulation through the appropriate physiological range of motion and center of rotation as the baseplates provide a stable platform for implantation. CONCLUSIONS: An intervertebral disc prosthesis has been designed and has demonstrated mechanical performance beyond what is required physiologically under preliminary testing.

Alloys↗
PubMedDate not supplied

The effect of end screw orientation on the stability of anterior instrumentation in cyclic lateral bending.

BACKGROUND CONTEXT: Screw pullout at the proximal or distal end of multilevel anterior instrumentation can occur clinically. Previous laboratory studies have shown that angulation of vertebral body screws increases screw pullout strength and stability in toggling. PURPOSE: To determine the effect of end screw angulation on instrumentation construct stability after cyclic, lateral bending. STUDY DESIGN: A biomechanical study in calf spines comparing two anterior spinal instrumentation constructs, one with parallel polyaxial screws and the other with angled polyaxial end screws. METHODS: Sixteen instrumented constructs were made from eight thoracic (T8-T12) and eight lumbar calf spines (L1-L5). Eight (four lumbar specimens and four thoracic specimens) had five bicortical screws inserted mid-body and parallel to the end plates. The other eight specimens had two screws angled toward the superior end plates of the top two vertebrae; the middle vertebra had a mid-body screw parallel to the end plate, and the bottom two vertebrae had screws angled towards their inferior end plates. The constructs were then cycled in lateral bending, and the displacements of the two instrumentations with a 10 N-m bending load were compared. RESULTS: After 10,000 cycles, constructs with parallel end screws exhibited twice the average displacement than those with angled screws: 5.4 mm versus 2.9 mm (p=.031). CONCLUSION: The use of angled screws at the ends of anterior constructs demonstrated increased construct stability after cycling compared with traditional transverse screws. Although angled screw insertion is technically more difficult and is possible only with specific screw designs, its use might increase instrumentation longevity.

Animals↗
PubMedDate not supplied

Paraplegia after lumbosacral nerve root block: report of three cases.

BACKGROUND CONTEXT: Lumbar nerve root blocks and epidural steroid injections are frequently employed in the management of degenerative conditions of the lumbar spine, but relatively few papers have been published that address the complications associated with these interventions. Serious complications include epidural abscess, arachnoiditis, epidural hematoma, cerebrospinal fluid fistula and hypersensitivity reaction to injectate. Although transient paraparesis has been described after inadvertent intrathecal injection, an immediate and lasting deficit has not been previously described as sequelae of a nerve root block. PURPOSE: We present three cases in which either persisting paraplegia or paraparesis occurred immediately after administration of a lumbar nerve root block and propose a mechanism for this devastating but previously unreported complication. STUDY DESIGN/SETTING: Case reports of three patients. PATIENT SAMPLE: Three patients, two women and one man ranging in age from 42 to 64 years, underwent three procedures performed at three different facilities, in the hands of two different injectionists. In each instance, penetration of the dura was not thought to have occurred. In two procedures the needles were placed transforamenally, one at L3-4 on the left and one at L3-4 on the right, and in the third the needle tip was placed immediately lateral to the S1 nerve root. OUTCOME MEASURES: Patient follow-up data from medical office records. METHODS: In each case, needle placement was verified with injection of a contrast media in conjunction with either computerized tomography or biplanar fluoroscopy. No backbleeding or cerebrospinal fluid was encountered upon aspiration in any of the procedures. Magnetic resonance imaging (MRI) was performed within 48 hours of injury in all patients. RESULTS: In each patient, paraplegia suddenly ensued after instillation of the steroid solution and, in each instance, postprocedure MRI revealed increased signal in the low thoracic spinal cord on T2-weighted imaging consistent with edema. The sudden onset of neurological deficit and the imaging changes noted in the spinal cord point to a vascular explanation for these injuries. We postulate that in these patients the spinal needle either penetrated or caused injury to an abnormally low dominant radiculomedullary artery, a recognized anatomical variant. This vessel, also known as the artery of Adamkiewicz, in 85% of individuals arises between T9 and L2, usually from the left, but in a minority of people may arise from the lower lumbar spine and rarely even from as low as S1. The artery of Adamkiewicz travels with the nerve root through the neural foramen and irrigates the anterior spinal artery. Injury of it or injection of particulate matter into it, as what may happen with the commonly used epidural steroid injectates, may result in infarction of the lower thoracic spinal cord, producing the clinical and imaging findings seen in these three patients. CONCLUSIONS: We present the cases of three patients who had lasting paraplegia or paraparesis after the performance of a nerve root block. We propose that the mechanism for this rare but devastating complication is the concurrence of two uncommon circumstances, the presence of an unusually low origin of the artery of Adamkiewicz and an undetected intraarterial penetration of the procedure needle.

Adult↗
PubMedDate not supplied

Orthopaedic management of ankylosing spondylitis.

Ankylosing spondylitis is an inflammatory disease of unknown etiology that affects an estimated 350,000 persons in the United States and 600,000 in Europe, primarily Caucasian males in the second through fourth decades of life. Worldwide, the prevalence is 0.9%. Genetic linkage to HLA-B27 has been established. Ankylosing spondylitis primarily affects the axial skeleton and is characterized by inflammation and fusion of the sacroiliac joints, spine, and hips. The resultant deformity leads to severe functional impairment in approximately 30% of patients. Orthopaedic management primarily involves correction of hip deformity through total hip arthroplasty and, less frequently, correction of spinal deformity with spine osteotomy. Closing wedge osteotomies have the lowest incidence of complications. Whether patients with ankylosing spondylitis are at increased risk for heterotopic ossification remains controversial, but comparison with age- and sex-matched counterparts suggests no dramatically higher risk. Because of the high rate of missed fractures and complications after minor trauma in patients with ankylosing spondylitis, plain radiographs are usually not sufficient for evaluation. Thorough patient assessment should include a comprehensive history, physical examination, and laboratory studies.

Anti-Inflammatory Agents, Non-Steroidal↗