Khalil I Issa M.D Spine-Ortho. Nablus-Palestine UWO-London-ON-Canada

1. Decompressing and Fixing Symptomatic High Grade Dysplastic spondylolisthesis with S1 pedicular screws crossing into the inferior portion of L5 Case report. Khalil I Issa M.D Spine-Ortho. Nablus-Palestine UWO-London-ON-Canada T.Carey FRCS(C), C.Bailey FRCS(C)

2. Introduction • Spondylolisthesis is a radiographic/anatomic description which describes the anterolisthesis ( slip ) of a vertebra on the one immediately caudal (inferior) to it. • The degree of anterolisthesis can be defined by grade ranging from 1 to 5 with each additional grade representing an additional 25% of the distance from normal alignment to the stage of spondyloptosis (grade 5 or complete slip).

3. Introduction • Spondylolisthesis is usually classified by its etiology. • The most common classification is that by Wiltse: Dysplastic, Isthmic (Spondylolysis, lytic defect of the pars), Degenerative, Traumatic, Pathologic, and Post-Surgical.

4. Discussion • Dysplastic Spondylolisthesisis due to congenital dysplastic change of the facet producing the anterolisthesis. • This usually occurs at L5-S1. • The facet dysplasia can occur in the axial or sagital plane, or can be due to an elongation of the facets (Wiltse sub classification).

5. Discussion • The L5-S1 facet joint is oblique to the sagital and axial plane. The facets of the upper lumbar spine most closely parallel the sagital plane. As we descend caudally down the lumbar spine the facets close to the sagital plane. • Normally, the S1 superior facet is approximately 45 degrees to the sagital plane. The S1 facet is also oblique to the coronal and axial plane. Therefore, dysplasia in the sagital or axial plane implies the S1 facet is more parallel to the sagital or axial plane respectively, allowing the L5 inferior facet to “slide” anterior because the S1 facet is no longer acting like a buttress.

6. Discussion • Of all the spondylolisthesis types, congenital is most likely to produce neurological deficit by virtue of the anterolisthesis alone. • This is because the grade of the listhesis can often progresses greater than two and the posterior ring of L5 remains attached to its anteriorly displaced body. • The canal becomes narrowed between the posterior, superior corner of S1 and the anteriorly displaced L5 posterior elements resulting in subacute or acute cauda equina syndrome.

7. Discussion • Congenital spondylolisthesis is relatively rare. • It typically presents in children, adolescents, or young adults. • It more commonly presents with neurological symptoms or leg pain as opposed to back pain. • May require urgent treatment if it presents as cauda equina syndrome. • Some sort of decompression of the L5 lamina is required in association with a fusion, possible instrumentation procedure.

8. Case Presented as: • 11-year-old girl • A lot of growth over the last year • Tightness in her lower extremities. • Toe walking, particularly on the left • Underwent some stretching and massage-type exercises in an effort to address this. • Her symptoms didn’t resolve. • Referred on for assessment.

9. Presentation • She has been continuing to be active in sports including skating and hockey with discomfort. • Clinical examination showed a very dramatic picture with a standing position with flexion at the knee and the hip on the left side. • Unable to fully straighten her left leg without discomfort.

10. Presentation • She has an obvious step-off at the lumbosacral region with a flattened appearance to her buttocks. • Significant tightness in her lower extremities. • Straight leg raising on the left side was about 5 or 10 degrees and on the right side about 40 degrees with crossover pain onto her left leg

11. X-Ray • Full length as well as focused spine views. • Confirmed the clinical suspicion of a spondylolisthesis. • She had a dysplastic spondylolisthesis with a significant forward displacement of at least grade 3. • She had the changes associated with a dysplastic spondylolisthesis with a dome shaped top of S1 and a trapezoidal L5. • She had a significant slip angle of 24 degrees. • No other abnormalities are detected.

14. MRI • MRI showed an extremely tight stenosis.

17. Assessment • This young lady has a high-grade spondylolisthesis of the dysplastic variety. • She is getting compression of the nerve root at this area that accounts for her lower extremity symptoms. • She didn’t seem to have a frank radiculopathy at the moment but thought that it is certainly headed that way.

18. Assessment • She denied any bowel or bladder issues. • Assessed to need a fairly urgent intervention for this. • Requiring a posterior decompression followed by an in situ fusion likely from L4 to S1. • The necessity for careful monitoring of cauda equina syndrome.

19. Operative TechniqueDecompression • Jackson frame on the OSI table, prone. • We exposed from L4 to S1 there appeared to be a significant deformity with a marked forward displacement of L5/S1. • laminectomy of L5 and of L4 for decompression,the neural elements identified and followed out. • Significant tightness of both the L5 and S1 roots was seen.

20. Operative TechniqueDecompression • It was felt that it would be necessary to do an anterior decompression and therefore, by careful retraction of the thecal sac, we were able to do a removal of the posterior aspect of the sacral dome which resulted in a decreased pressure over the thecal sac. • It was felt that a reduction of this lip would be ill-advised due to the moderate tightness noted at the L5 root.

21. Operative TechniqueFixation • We used 5.5mm polyaxial screws and we ensured pedicle screws in L4 pedicles bilaterally. • We then placed 6.5 mm screws into S1 pedicle. Image intensification was used to help with the placement of the screws and we were able to place the S1 screws through the superior endplate of S1 across the 5-1 disc space into the inferior portion of the body of L5. • Then rods were contoured to appropriately fit between the screws and they were locked into place. • Allograft bone inserted. • She had neuromonitoring performed throughout the case and this was maintained within normal ranges at all times.

22. Post Operative Course • She did well postoperatively. • She was held over night in ICU and did quite well. • She was discharged to the floor the following day and gradually mobilized. She was seen by Physiotherapy and did well with mobilization. • She was discharged home on 4 days post operatively.

23. Post Operative2 weeks • Improving from a neurological point of view, and has less abnormal gait according • She still had some tightness • Physiotherapy to work on her hamstrings and heel cords. • TLSO with a hip extension to support her surgical site in an effort to ensure she does not get in to a pseudoarthrosis type situation.

24. Post Operative2 Months • Her incision is well healed. • Overall she is quite comfortable. • She has been working on trying to regain range of motion as she had quite tight hamstrings and heel cords. • 5 degrees above dorsiflexion on her right heel cord and about 5 below on her left side.

25. Post Operative2 Months • Her straight leg raising is about 50 to 60 degrees on the right and about 45 to 50 on the left, and she has popliteal angles about -45. • On and to continue TLSO to keep her restricted in her activities. • X-rays were obtained today and these show maintenance of the instrumentation with no interval changes since her postoperative films.

28. Post Operative4 Months • Doing quite well ,continued to attend physiotherapy once every two weeks but does physiotherapy approximately three times a day at home. She has minimal to no discomfort as well. • TLSO full time as well. • Able to dorsiflex to about 5-10 degrees bilaterally. Her straight leg raise has improved from previous and now is up to about 70 degrees bilaterally.

29. Post Operative4 Months • X-rays today as though her lumbar fusion looked good, however it is always difficult 100% to accurately find this via x-ray. • Overall she was doing quite well. • Allowed to get back to some activity as tolerated. • Allowed to ride a bike, skip and such. • Allowed to start to discontinue the use of her brace.

30. Results • It secures fixation when combining L5 to S1 keeping L5 in the construct • It gives the ability to skip the so much technically difficult L5 pedicular screws • It augments graft healing • It is safe and stable

31. Thank You