Introduction Defined as spondylolisthesis in an adult caused by a defect in the pars interarticularis (spondylolysis) pars defects usually acquired and caused by microtrauma Epidemiology incidence spondylolysis is seen in 4-6% of population increased prevalence in sports that involve repetitive hyperextension (gymnasts, weightlifters, football linemen) location 82% occur at L5/S1 11% occurs L4/5 (11%) due to forces in the lumbar spine being greatest at these levels and the facet being more coronal Pathophysiology foraminal stenosis adult isthmic spondylolisthesis at L5/S1 often leads to radicular symptoms caused by compression of the exiting L5 nerve root in the L5-S1 foramen compression can be caused by hypertrophic fibrous repair tissue of the pars defect uncinate spur formation of the posterior L5 body bulging of the L5/S1 disc lateral recess stenosis caused by facet arthrosis and hypertrophic ligamentum flavum central stenosis rare due to fact that these slips are usually only Grade I or II Prognosis relatively few patients (5%) with spondylolysis with develop spondylolisthesis slip progression more common in females slip progression usually occurs in adolescence and rare after skeletal maturity Classification Wiltse-Newman Classification Type I • Dysplastic: a congenital defect in pars Type II-A • Isthmic - pars fatigue fx Type II-B • Isthmic - pars elongation due to multiple healed stress fx Type II-C • Isthmic - pars acute fx Type III • Degenerative: facet instability without a pars fx Type IV • Traumatic: acute posterior arch fx other than pars Type V • Neoplastic: pathologic destruction of pars Myerding Classification Grade I • < 25% Grade II • 25-50% Grade III • 50-75% Grade IV • 75-100% Grade V • spondyloptosis Physical Exam Symptoms axial back pain most common presentation pain usually has a long history with periodic episodes that vary in intensity and duration leg pain usually a L5 radiculopathy usually caused by foraminal stenosis at the L5-S1 level neurogenic claudication caused by spinal stenosis characterized by buttock and leg pain worse with walking symptoms of neurogenic claudication rare because these slips rarely progress beyond Grade II cauda equina syndrome rare because these slips rarely progress beyond Grade II Physical exam L5 radiculopathy ankle dorsiflexion and EHL weakness Imaging Radiographs recommended views obtain AP, lateral, obliques, and flexion-extension views findings AP deformity in coronal plane lateral will see spondylolisthesis and pars defect flexion-extension instability defined as 4 mm of translation or 10° of angulation of motion compared to adjacent motion segment measurements pelvic incidence pelvic incidence = pelvic tilt + sacral slope a line is drawn from the center of the S1 endplate to the center of the femoral head a second line is drawn perpendicular to a line drawn along the S1 endplate, intersecting the point in the center of the S1 endplate the angle between these two lines is the pelvic incidence (see angle X in figure above) correlates with severity of disease pelvic incidence has direct correlation with the Meyerding–Newman grade pelvic tilt sacral slope = pelvic incidence - pelvic tilt a line is drawn from the center of the S1 endplate to the center of the femoral head a second vertical line (parallel with side margin of radiograph) line is drawn intersecting the center of the femoral head the angle between these two lines is the pelvic tilt (see angle Z in figure above) sacral slope pelvic tilt = pelvic incidence - sacral slope a line is drawn parallel to the S1 endplate a second horizontal line (parallel to the inferior margin of the radiograph) is drawn the angle between these two lines is the sacral slope (see angle Y in the figure above) MRI views T2 parasagittal images are best study to evaluate for foraminal stenosis and compression of neural elements Treatment Nonoperative oral medications, lifestyle modifications, therapy indications most patients can be treated nonoperatively techniques activity restriction NSAID role of injections unclear bracing may be beneficial especially in the acute phase Operative L5-S1 decompression and instrumented fusion +/- reduction indications L5-S1 low-grade spondylolisthesis with persistent and incapacitating pain that has failed 6 months of nonoperative management (most common) progressive neurologic deficit slip progression cauda equina syndrome reduction improved sagittal balance with reduction risk of stretch injury to L5 nerve root with reduction L4-S1 decompression and instrumented fusion +/- reduction indications L5-S1 high-grade spondylolithesis with persistent and incapacitating pain that has failed 6 months of nonoperative management ALIF indications can be used successfully to treat low-grade isthmic spondylolisthesis even when radicular symptoms are present cannot be used to treat high grade isthmic spondylolisthesis due to translational and angular deformity outcomes studies have shown good to excellent results in 87-94% at 2 years Surgical Techniques L5/S1 wide decompression and instrumented fusion approach posterior midline decompression indicated in adult with leg pain below knee usually involves Gill laminectomy and foraminal decompression removal of loose lamina and scared pars defect allows decompression of nerve root a Gill decompression is destabilizing and should be combined with fusion fusion posterolateral fusion is standard interbody fusion (PLIF/TLIF) commonly performed posterior lumbar interbody fusion (PLIF) involves insertion of device medial to facets transforaminal lumbar interbody fusion (TLIF) requires facetectomy and more lateralized and transforaminal approach to the disc space cons interbody fusion has increased operative time with greater blood loss and longer hospitalizations Anterior Lumbar Interbody Fusion (ALIF) approach usually done through trans-retroperitoneal approach decompression decompression of nerve root done indirectly by foraminal distraction via restoration of disc height fusion grafts used include autologous iliac crest, structural allograft, and cages of various materials pros may increase chance of union by more complete discectomy and endplate preparation allows improved restoration of disc height cons retrograde ejaculation and sexual dysfunction persistent radiculopathy due to inadequate indirect foraminal decompression persistent low back pain may be caused by nociceptive pain fibers in pars defect that are not removed in an anterior procedure alone preferred treatment is surgeon dependent with each technique having similar outcomes Complications Psuedoarthrosis Dural Tear
Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. Posterior Laminectomy and Instrumented Fusion Andrew Hsu Spine - Adult Isthmic Spondylolisthesis Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. Single Level Lumbar Decompression and Fusion (TLIF) Orthobullets Team Spine - Adult Isthmic Spondylolisthesis
QUESTIONS 1 of 12 1 2 3 4 5 6 7 8 9 10 11 12 Previous Next You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ12SP.63) Figures A and B show a 33-year-old man with axial back pain and bilateral leg pain. Which of the following is the cause of this type of spondylolisthesis? Review Topic QID: 3761 FIGURES: A B Type & Select Correct Answer 1 L5 arch congenital abnormality 16% (250/1597) 2 Fatigue fracture of the pars interarticularis 70% (1116/1597) 3 Degenerative instability with intact pars interarticularis 4% (60/1597) 4 Traumatic fracture with intact pars interarticularis 9% (142/1597) 5 Pathologic local bone disease 1% (18/1597) L 3 Select Answer to see Preferred Response SUBMIT RESPONSE 2 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ12SP.3) A 64-year old female presents with severe low back pain and bilateral leg pain, worse on the right. An AP and lateral radiograph in extension are shown in Figures A and B respectively. After extensive nonoperative management fails to provide any significant pain relief, surgical intervention is performed. A laminectomy and instrumented fusion is performed and shown in Figure C. What would be the most likely neurologic deficit found in the postoperative period? Review Topic QID: 3701 FIGURES: A B C Type & Select Correct Answer 1 Weakness to ankle plantar flexion. 14% (701/4882) 2 Weakness to great toe extension 81% (3962/4882) 3 Weakness to Hip Flexion 1% (34/4882) 4 Loss of the patellar reflex 1% (32/4882) 5 Bowel and bladder dysfunction saddle anesthesia 3% (126/4882) L 2 Select Answer to see Preferred Response SUBMIT RESPONSE 2 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ11.169) A correlation has been found between Pelvic Incidence (PI) and spondylolisthesis. Based on the angles X,Y, and Z shown in Figure A, B, and C, which of the following most accurately determines the Pelvic Incidence (PI) in this patient? Review Topic QID: 3592 FIGURES: A B C Type & Select Correct Answer 1 Angle Z + Angle Y 64% (1706/2665) 2 Angle X - Angle Y 7% (193/2665) 3 Angle X - Angle Z 13% (348/2665) 4 Angle Z 12% (316/2665) 5 Angle Y 3% (72/2665) L 4 Select Answer to see Preferred Response SUBMIT RESPONSE 1 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ10.8) Studies have shown a direct relationship between pelvic incidence and isthmic spondylolisthesis, suggesting that pelvic anatomy has a direct influence on the development of this condition. Which angle in Figure A-E best illustrates the measurement of pelvic incidence. Review Topic QID: 3096 FIGURES: A B C D E Type & Select Correct Answer 1 Angle E (Figure A) 3% (73/2835) 2 Angle X (Figure B) 76% (2142/2835) 3 Angle Z (Figure C) 14% (388/2835) 4 Angle Y (Figure D) 4% (126/2835) 5 Angle V (Figure E) 3% (92/2835) L 3 Select Answer to see Preferred Response SUBMIT RESPONSE 2 You have 100% on this question. Just skip this one for now. Take This Question Anyway This is an AAOS Self assessment question. Orthobullets was not involved into the editorial process, and does not have the ability to alter. If you prefer to hide SAE questions on topics simply turn them off in your Content Settings (SAE09SN.23) An adult patient with a grade I isthmic spondylolisthesis at L5-S1 is most likely to have weakness of the Review Topic QID: 6811 Type & Select Correct Answer 1 flexor hallucis longus. 6% (11/182) 2 quadriceps. 2% (3/182) 3 gastrocsoleus. 13% (24/182) 4 extensor hallucis longus. 78% (142/182) 5 iliopsoas. 1% (1/182) L 2 Select Answer to see Preferred Response SUBMIT RESPONSE 4 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ09.124) You are seeing a 28-year-old female for lower back pain after she fell off a horse 2 days ago. She has no neurologic deficits. A lateral radiograph and axial CT scan are shown in Figures A and B, respectively. What is the most appropriate first line of treatment? Review Topic QID: 2937 FIGURES: A B Type & Select Correct Answer 1 Observation, mobilization, and further treatment based on symptoms 68% (2088/3082) 2 Spinal casting and bed rest for 6 weeks 0% (9/3082) 3 Thoracolumbosacral orthosis for 6-8 weeks 25% (769/3082) 4 Open reduction and internal fixation 2% (55/3082) 5 L5 to S1 posterior spinal fusion with instrumentation 5% (145/3082) L 3 Select Answer to see Preferred Response SUBMIT RESPONSE 1 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ06.106) A 26-year-old male presents with chronic back and bilateral leg pain that has not improved with extensive nonoperative management including physical therapy, oral medications, and corticosteroid injections. Radiographs are shown in Figure A. What is the most appropriate next step in treatment? Review Topic QID: 292 FIGURES: A Type & Select Correct Answer 1 Placement of epidural spinal stimulator 0% (12/2406) 2 Lumbar decompression alone 0% (8/2406) 3 Lumbar decompression with L5 to S1 posterior lumbar fusion 31% (754/2406) 4 Lumbar decompression, L4 to S1 posterior lumbar fusion, and anterior column support 67% (1602/2406) 5 Minimally invasive direct lateral interbody fusion with percutaneous pedicle screw placement 1% (23/2406) L 3 Select Answer to see Preferred Response SUBMIT RESPONSE 4
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