Lumbar disc replacement-lesson learned

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Information about Lumbar disc replacement-lesson learned
Science-Technology

Published on April 21, 2009

Author: adukt

Source: authorstream.com

Discography findings and Lumbar Disc ReplacementLessons learned : Discography findings and Lumbar Disc ReplacementLessons learned Dr Rajendra Prasad FRCS,FRCS(SN) Senior consultant and clinical coordinator Department of neurosurgery Apollo hospital, New Delhi. Role of discography : Role of discography Discography is currently used to determine whether the disc is the source of pain in patients with predominantly back pain. Lumbar Discography : Lumbar Discography CT Scans and MRI are excellent for investigating radicular pain, but offer little in the investigation of back pain and somatic referred pain. Disks selected for treatment are those that are symptomatic on stimulation and that express loss of signal intensity on MRI. Failing to find a painful disk on discography should preclude surgery; so too should finding multiple painful disks or obtaining indeterminate results. Supporting evidence : Supporting evidence Bernard prospectively studied 250 patients with low back pain who underwent lumbar discography followed by CT scan. In 93% of the patients, the combined discogram/CT provided significant information regarding equivocal or multiple level abnormalities and type of herniation, defining surgical options, and evaluating previously operated spines. In 94% of the patients, discography/CT correctly predicted disk herniation as protruded, extruded, sequestrated, or internally disrupted. Discography provokes pain by the following mechanisms : Discography provokes pain by the following mechanisms Increase intradiscal pressure. In an abnormal disk, stretching of the annular fibers of the disk may stimulate nerve endings. The injection may result in some biochemical or neurochemical stimulation that causes pain. Increase pressure at the end plates, or pressure may be transferred to the vertebral body throughout the end plate, resulting in an increase in intravertebral pressure. The presence of pain on injection of a seemingly normal disk may be due to transfer of pressure from the injection to an abnormal, symptomatic adjacent disk. Interpretation : Interpretation Pain at low pressures is most likely due to chemical irritation. Low resistance generally is associated with a tear through the outer annulus. Pain at high pressures may be due to mechanical irritation, end-plate deflection, or stimulation of pressure receptors. Dallas classification : Dallas classification Type 1: The discogram is normal manometrically, volumetrically, and radiographically and produced no pain. The discogram/CT scan showed contrast to be located centrally in the axial and sagittal projections. Type 2: This is identical to type 1 except that it is positive for reproduction of pain. Type 1 Type 2 Slide 8: Type 3: Annular tears lead to a radial fissure. This group is subdivided further into types 3a (ie, posterior radial fissure), 3b (ie, fissure radiates posterolateral), and 3c (ie, fissure extends lateral to a line drawn from the center of the disk tangential to the lateral border of the superior articulating process). Type 4: Once the radial fissure reaches the periphery of the anulus fibrosus, nuclear material may protrude, causing the outer annulus to bulge. Type3 Type 4 Slide 9: Type 5: When the outer annular fibers rupture, nuclear material may extrude beneath the posterior longitudinal ligament and come in direct contact with either the dura or a nerve root. Type 6: When the extruded fragment is no longer in continuity with the interspace, it is said to be sequestrated. Manometrically, volumetrically, and radiographically, the discograms are always abnormal. Familiar pain may be reproduced only if enough pressure is generated against the free fragment to cause stimulation of the pain-sensitive structures. Type 5 Type 6 Slide 10: Type 7: The end stage of this degeneration is internal disc disruption, characterized by multiple annular tears. The discograms are abnormal manometrically and volumetrically, and familiar pain may or may not be reproduced. Radiographically, the contrast usually fills the entire interspace in a chaotic fashion. The discogram/CT scan shows contrast extravasation throughout multiple annular tears. Type 7 Complications : Complications Headache, meningitis, intrathecal hemorrhage, arachnoiditis, severe reaction to accidental intradural injection, damage to the disc, urticaria, retroperitoneal hemorrhage, nausea (2%) Disc herniations. Five cases of acute lumbar disk herniation precipitated by discography have been reported. New-onset or a persistent exacerbation of radicular symptoms following provocative discography merits further investigation (Poynton, 2005). Discitis - 2-3% when a single-needle technique is used and 0.7% when a double-needle technique is used. 11 patients : Provocation positive- 9 patients Dallas IIIc - 1 Dallas IV – 1 Dallas V- 1 Dallas VI- 2 Dallas VII -4 Provocation negative – 2 patients- Dallas I 11 patients History : History 58 year old male Low back pain pain since- 1999 Increased in intensity since two year Radiation to lower limbs R>L EMG NCV – bilateral chronic L5,S1 radiculopathy Slide 14: Flexion Extension No listhesis Slide 15: Modic type I Grade 0 Grade 1 Slide 17: Discogram Type IV Vaccum phenomenon Preop planning : Preop planning Slide 19: What is the amount of segmental lordosis? close to 6°? ? 6° prosthesis close to 11°? ? 11° prosthesis close to 0°? ? 3° prosthesis What is the inclination of the segment? less than 15°? ? 0° inferior plate more than15°? ? angled inferior plate Slide 20: Disc line Border line Corridor line Incison Sacral promontory Disc space Border line Disc line 2cm Slide 21: Discectomy Midline Parallel distraction Keel cutting Implant insertion Slide 23: Metal on Polyethylene Slide 24: Mobilised day1 Contraindications : Contraindications Spondylolisthesis at affected level or adjacent level. Posterior facet joint damage and or disease at affected level, including facet osteoarthritis, pars fracture, prior laminectomy. Smoking? Slide 26: Spinal canal stenosis Overlying thoracolumbar khyphosis or kyphosis at level of replacement ? Severe Osteopenia , osteoporosis, or osteomalacia Patient selection-Discussion : Patient selection-Discussion Central disc herniation Patients with listhesis Not suitable for disc replacement Post discectomy patients : Post discectomy patients Rule out discitis and epidural fibrosis, give facet block. Adjacent segment degenerative disease : Adjacent segment degenerative disease Spinal stenosis : Spinal stenosis Neurogenic claudication associated with central canal stenosis or lateral recess stenosis(Bony) is an absolute contraindication for total disc replacement. Foraminal stenosis - Functional foraminal or soft-tissue–induced foraminal stenosis (with or without radicular symptoms) are good candidates for total disc replacement. Opening up of foramen Facet joint hypertrophy : Facet joint hypertrophy Grade 0 Grade 1 Grade 2 Grade 3 Slide 32: T2-weighted axial MR image shows thin, well-demarcated hyperintense line (straight arrows), presumably caused by combination of intraarticular fluid and superficial parts of articular cartilage. Hypointense line (curved arrows), in part, represents subchondral bone and deep layers of articular cartilage. Findings suggestive of subchondral sclerosis, osteophytes, and cysts are absent. Grade 0 normal width of the facet joint space (2-4 mm) Slide 33: Axial T2-weighted MR image shows almost no visible cartilage (arrows). Beginning facet joint hypertrophy (arrowheads) can be seen on left side. Grade 1 narrowing of the facet joint space (< 2 mm) Slide 34: Axial T2-weighted MR image shows joint space narrowing, subchondral sclerosis (curved arrows), and small cyst formation (straight arrow), indicating moderate facet joint degeneration. Grade 2 Slide 35: T2-weighed axial MR image shows facet joint hypertrophy with osteophytes (large straight arrows), subchondral erosions (curved arrow), and hypertrophy of ligamentum flavum (small straight arrows). Grade 3 MODIC-SIGNS (valid only in black discs) : MODIC-SIGNS (valid only in black discs) MODIC I – EDEMA- T1Low intensity , T2 high intensity MODIC II –FAT- High intensity on T1 andT2 MODIC III- SCLEROSIS - Low intensity on T1 and T2 Role of discography : Role of discography Level of bifurcation of vessels : Level of bifurcation of vessels Oblique maverick disc Excessive retraction Metal on metal L4-5 Disc replacementcharite : L4-5 Disc replacementcharite Metal on Polyethylene Slide 40: L5-S1 Disc replacement charite David T Long-term results of one-level lumbar arthroplasty: minimum 10-year follow-up of the CHARITE artificial disc in 106 patients.Spine. 2007 Mar 15;32(6):661-6. : David T Long-term results of one-level lumbar arthroplasty: minimum 10-year follow-up of the CHARITE artificial disc in 106 patients.Spine. 2007 Mar 15;32(6):661-6. 82.1% had either an excellent or good clinical outcome. 89.6%, including 77.8% of patients with hard labor level returning to the same level of work. The mean ROM in flexion-extension was 10.1 degrees , in lateral bending it was 4.4 degrees 90.6% of implanted prostheses were still mobile. Eight patients (7.5%) required posterior instrumented fusion. 5 cases (4.6%) of postoperative facet arthrosis 3 cases (2.8%) of subsidence 3 cases (2.8%) of adjacent-level disease 2 cases (1.9%) of core subluxation. Decision making : Decision making Type II modic change Grade II facet arthropathy Posterior osteophtes Slide 43: Faulty implant holders Morbidity of anterior procedure : Morbidity of anterior procedure Incidence of vascular injury and retrograde ejaculation- Risks of ALIF surgery include damage to large blood vessels and in males, retrograde ejaculation in around 1% of cases (Fowler, Dall et al., 1995). Slide 45: Thank you

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