|Year : 2018 | Volume
| Issue : 2 | Page : 116-122
Percutaneous endoscopic interlaminar lumbar discectomy for high-grade inferiorly migrated L5-S1 disc: A case report with technical review
Manish Raj1, Hyeun S Kim2, Kailash Kothari3, Anurag Agarwal4, Santosh Tripathi5, Shobhit Bharadwaj6
1 Department of Interventional Spine and Pain Medicine, Yatharth Super Speciality Hospital, Noida, India
2 Department of Neurosurgery, Nanoori Hospital, Seoul, South Korea
3 Department of Interventional Spine and Pain, Pain Clinic of India, Mumbai, India
4 Department of Anaesthesiology and Pain Management, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India
5 Department of Neuroscience, Metro Neuro Hospital, Gwalior, India
6 Department of Orthopedic Surgery, Yatharth hospital, Noida, India
|Date of Web Publication||31-Aug-2018|
Dr. Manish Raj
Department of Interventional Spine and Pain Medicine, Yatharth Super Speciality Hospital, Sector 110, Noida, Uttar Pradesh,
Source of Support: None, Conflict of Interest: None
L5-S1 disc has always been a difficult disc to target by rigid endoscope because of anatomical limitations. In this study, we have described the technique to overcome difficulty faced during endoscopic disc decompression of high-grade inferior migrated disc at L5-S1. We performed percutaneous endoscopic inter-laminar lumbar discectomy (PEILD) for removal of high grade inferiorly migrated disc and preserved the functional structures. After institutional review board approval, details of the patient with high-grade inferior migration at L5-S1 disc were reviewed. The patient was operated by a single specialist with use of the percutaneous endoscopic inter-laminar technique for high-grade inferior migrated extruded disc. Description of our technique & result is the focus of this study. The average VAS score was reduced from 9 pre-operatively to 3 post-operatively & to 1-2 within 2 weeks. Post-operative plantar flexion of foot improved from 2 to 4 immediately and up to 5 within 2 weeks. Ankle jerk reflex improved from 1+ to 2+. The pain severity score on BPI reduced from 9 to 3 postoperatively. Post-operative MRI showed that the high grade inferiorly ruptured disc had been successfully removed. We obtained excellent results in treating inferior extruded disc at L5-S1 using endoscopic inter-laminar approach. Inter-laminar endoscopic discectomy can be used as a safe yet minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a high grade inferior migrated lumbar disc herniation.
Keywords: Endoscopic disc discectomy, high-grade inferior migration, interlaminar endoscopic discectomy
|How to cite this article:|
Raj M, Kim HS, Kothari K, Agarwal A, Tripathi S, Bharadwaj S. Percutaneous endoscopic interlaminar lumbar discectomy for high-grade inferiorly migrated L5-S1 disc: A case report with technical review. Indian J Pain 2018;32:116-22
|How to cite this URL:|
Raj M, Kim HS, Kothari K, Agarwal A, Tripathi S, Bharadwaj S. Percutaneous endoscopic interlaminar lumbar discectomy for high-grade inferiorly migrated L5-S1 disc: A case report with technical review. Indian J Pain [serial online] 2018 [cited 2018 Dec 19];32:116-22. Available from: http://www.indianjpain.org/text.asp?2018/32/2/116/240282
| Introduction|| |
Since Dandy and Mixter in the early 1900s first described the operative treatment of lumbar disc herniation, it has become the most common disease of the spine requiring surgical treatment., Among the operative methods used for lumbar discectomy, the microdiscectomy technique is considered to be the gold standard procedure for symptomatic lumbar disc herniation that has not improved with conservative management. However, due to development of relevant equipment such as high-resolution rigid rod lens, endoscopic forceps, drill, burr, radio-frequency probe, and laser, it has now become possible to treat most lumbar disc herniation with percutaneous endoscopic discectomy.
There are certain advantages of endoscopic discectomy over open surgery, including clear visualization and targeted fragmentectomy under the guidance of an endoscope and fluoroscope, less damage to the paraspinal muscles and other normal tissues leading to early rehabilitation and return to work, and the procedure can be performed under local anesthesia. Posterolateral working channel transforaminal endoscopic discectomy is one of the widely used endoscopic procedure, but the application of the transforaminal approach to the L5-S1 disc space is limited because of the anatomic constraints in certain individuals. A high iliac crest, a large L5 transverse process, a large facetal mass, or a narrowed neural foramen all serve to limit clinical access to the L5-S1 disc space., In such situations, the interlaminar endoscopy for decompression combines the advantages of posterolateral endoscopy with good visualization of the pathology.
Though few authors have published work on the transiliac endoscopic approach for superiorly and interlaminar approach for inferiorly migrated disc herniation, very less work on high-grade down migration via interlaminar approach is carried out., In our view, a safe and less destructive approach with technical modification to address the high-grade down migrated disc herniation at L5-S1 is available., We performed an interlaminar axillary approach to reach the extruded disc and adequate decompression was carried out.
| Case Report|| |
A 40-year-old woman presented with complaints of severe low backache radiating to right leg since 15 days with numbness and weakness in the right leg. The lesion of the patient was high-grade inferiorly extruded disc lying posterior of S1 vertebrae causing lumbar canal stenosis. According to preoperative sagittal magnetic resonance imaging (MRI), disc migration was classified into four zones depending on the direction and distance from the disc space [Figure 1]. The origin for extrusion seems to be L5-S1 disc, which was confirmed radiologically [Figure 2],[Figure 3],[Figure 4]. The patient underwent percutaneous endoscopic interlaminar lumbar discectomy (PEILD) via an ipsilateral interlaminar axillary approach. Outcomes were evaluated using visual analog scale (VAS) score, brief pain inventory (BPI) and adequate decompression were checked by preoperative and immediate postoperative MRI.
|Figure 1: Grades of migration. Up-migrated Zone H: from the inferior margin of upper pedicle to 3 mm below of the inferior margin of upper pedicle, up-migrated Zone L: from 3 mm below of the inferior margin of upper pedicle to the inferior margin of upper vertebral body, down-migrated Zone L: from the superior margin of lower vertebral body to the center of the lower pedicle, and down-migrated Zone H: from the center to the inferior margin of lower pedicle|
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|Figure 2: T2-weighted sagittal view of arrow showing high grade inferiorly migrated disc|
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| Operative Technique|| |
Before the surgery, anatomical structures in the pathway of instruments were evaluated on preoperative MRI. Interlaminar distance from the lower border of L5 lamina and superior border of S1 lamina was measured and it was found out to be 22 mm. With 22-mm interlaminar distance, we can easily insert 8-mm working sleeve, but we had to confirm the angle of trajectory inferiorly as the disc was lying posterior to the sacral vertebrae and compressing dural sheath.
The patient received preoperative intravenous (IV) antibiotic injection cephazolin (1–2 g IV) 60 min before the procedure and was placed in prone position on a radiolucent table. The operative area was cleaned and draped. The whole procedure was performed with conscious sedation using midazolam and fentanyl. The patient received interlaminar epidural anesthesia at L2-L3 with continuous infusion of an analgesic dose of ropivacaine (0.25%) at 5–10 mL/h with a catheter in situ, and the procedure proceeded with continuous feedback from the patient as she was fully conscious.
Fluoroscopic guidance was used to identify the L5-S1 disc space. A vertical midline was drawn on the skin, followed by a horizontal line across the center of the targeted disc under C-arm. The skin was marked at midpoint of the sacral lamina of ipsilateral side (half distance between midline and lateral most part of flavum or superior articular process of S1 in posteroanterior C-arm view). Evocative discography was performed with a solution (indigo carmine 3 mL + 3 mL of radiopaque dye Omnipaque 300, Wipro ge health care, India) after putting needle further inside the disc.
The skin incision was made with 11-number knife parallel to midline for 6–7 mm. Single obturator was inserted till ligament flavum with the maintenance of trajectory 15 degree in the coronal plane towards posterior mid of S1 vertebral body and confirmed in antero-posterior (AP) and lateral view of C-arm. A working channel was inserted over the obturator. The obturator was removed and the endoscope was inserted. The ligament flavum was split with a probe and the flavectomy was carried out [Figure 5].
Once entered in the spinal canal, the epidural fat was dissected with a radio-frequency electrode and forceps, and all intracanal structures such as exiting S1 nerve root, dural sheath, lateral recess, and articular processes were visualized. The bevel of the working channel was penetrated through the split point of the ligament flavum and was rotated protecting the nerve root and surrounding structures. A partially stained extruded disc compressing an exiting nerve root and dural sleeve was identified. The ruptured disc was removed with endoscopic forceps through the axillary route [Figure 6]. To find the remnant disc, working channel angled about 45 degrees from caudal to cranial toward the lower part of the ruptured disc [Figure 7]. With use of radio-frequency cautery, annular sealing was carried out. After decompression of the lesion and hemostasis, the scope was removed and skin sutures were applied. The adequate discectomy of the lesion was confirmed with immediate postoperative MRI [Figure 8],[Figure 9],[Figure 10].
|Figure 6: Artistic image showing caudal angulation through S1 lamina into axillary region|
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|Figure 7: Endoscope direction from cranial (CR) to caudal (CAU), in some cases partial laminectomy may be required for correct angulation|
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|Figure 9: Postoperative T2-weighted sagittal view showing complete removal of extruded disc fragment|
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|Figure 10: Postoperative T2-weighted axial view showing complete removal of extruded disc fragment and free thecal sac|
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| Results|| |
The average VAS score was reduced from 9 preoperatively to 3 postoperatively and to 1–2 within 2 weeks. Postoperative plantar flexion of foot improved from 2 to 4 immediately and up to 5 within 2 weeks. Ankle jerk reflex improved from 1+ to 2+. The pain severity score on BPI reduced from 9 to 3 postoperatively. Postoperative MRI showed that the high-grade inferiorly ruptured disc had been successfully removed [Figure 11], [Figure 12], [Figure 13]. No complications such as dysesthesia, hematoma, or infection were reported. The patient did not require any additional procedure.
|Figure 11: Postoperative T2-weighted axial view showing complete removal of extruded disc fragment & free right S1 nerve root|
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|Figure 12: Pre-operative sagittal & axial T2 MRI for comparative analysis, showing high grade inferior migration in sagittal view & axillary herniation compressing thecal sac & nerve in axial view|
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|Figure 13: Post-operative sagittal & axial T2 MRI for comparative analysis, showing complete removal of extruded fragment, free dural sheath & nerve root|
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| Discussion|| |
Performing a lumbar discectomy for a patient with incapacitating sciatica can be one of the most dramatically successful procedures in modern medicine. Disc herniation is an unfortunate event that can occur during the natural history of degeneration of all discs.
Since Kambin and Sampson first introduced lumbar disc decompression via a posterolateral approach, remarkable advances in percutaneous endoscopic lumbar disc procedures have been reported. With the development of various instruments related to spinal endoscopic procedures, now nearly all symptomatic lumbar disc herniation can be treated via endoscope in expert hands.
As L5-S1 level has considerable anatomical features, such as high iliac crest, facet joint hypertrophy, relatively narrow foramen, and wide interlaminar space, several approaches to the ruptured disc at the L5-S1 level have been considered, such as transforaminal, interlaminar, and transiliac approaches.,,
For high-grade inferior migration at L5-S1, Choi et al. while performing transforaminal approach observed that properly visualization of inferiorly migrated fragment requires resection of the superior articular process of the lower vertebra and sometimes even medial pediculectomy is performed where the upper and medial border of that pedicle is removed to gain access to the fragment. Lee et al. have also mentioned the requirement of anterior facet removal for zone 4 herniation.
Using an excessive cranial-to-caudal skin entry point because of the high iliac crest increases the possibility of encountering an existing nerve root injury. Discography was performed via transforaminal approach as it is not advisable to do discography by interlaminar approach as the exact location of dural sleeve and exiting S1 root is not known, though few authors promote interlaminar discography for shoulder type L5-S1 herniation. We performed the transforaminal approach for evocative discography with 3 mL of indigo carmine mixed with radiopaque contrast Omnipaque in 3:3 mL concentration. Indigo carmine as basic agent, stains the acidic degenerated nucleus pulposus. We performed discography to observe if there is any track of ruptured material with the L5-S1 disc and observed inferiorly leaking discography solution to anterior epidural space in lateral fluoroscopic view.
As insertion of the working channel at a sharp angle may cause injury to the thecal sac, it is important to dock the working channel lateral to dural sheath and medial to exiting root (axillary approach) after identification of neural structures; failure to identify canalicular structure can lead to the dural tear. In addition, splitting a ligament flavum without clarifying the boundaries of the bone and ligament flavum may cause exiting nerve root injury, thereby requiring attention.
Lee et al. showed that a satisfactory outcome was obtained in 78.9% (30/38) of the patients with highly migrated disc herniation with the percutaneous endoscopic transforaminal lumbar discectomy technique, but it was limited to mid-grade inferiorly migrated disc. Lee et al. recommended that open surgery should be considered for far-migrated disc herniation. But the open discectomy, such as paramedian Wiltse approach hemilaminectomy, need extensive resection of the lamina especially in the region of the pars interarticularis. This may result in iatrogenic instability and increased postoperative morbidity. Microscopic lumbar discectomy also requires partial facetectomy; if more than 40%–50% of the facet is removed, instability may arise, inducing postoperative pain., The discs, facet joints, supraspinous ligaments, and paraspinal muscles of the lumbar spine are important structures that maintain the stability of segmental motion. Instability increases when surrounding structures are damaged. PEILD via ipsilateral interlaminar approach can maximally preserve these structures.
Choi et al. used the interlaminar technique for intracanal herniation via shoulder and axillary approach; though good results were observed for axillary type herniation, the grade of herniation could not be established. Raj et al. have demonstrated the use of interlaminar approach for superiorly migrated high-grade sequestration at L5-S1 without causing any iatrogenic instability.
Interlaminar approach not only renders us direct visualization and removal of extruded fragment but also helps in annular sealing after fragmentectomy. Kim et al. mentioned this technique, resulting in a lower early recurrence rate compared to the transforaminal approach without annular sealing. This new operative technique may be helpful in reducing the early recurrence of the lumbar disc.
If the interlaminar space is relatively narrow, it might render an approach to inferior migration difficult, as the laminar would block the trajectory [Figure 7]. In such a case, an approach trajectory can be acquired by undercutting the superior margin of the lesion-side facet and lamina using an endoscopic drill. Fortunately, in this case, we were able to approach the extrusion site without using an endoscopic drill. The outcomes were satisfying; however, further study will be needed with more number of cases to establish the effectiveness of PEILD for high-grade inferiorly extruded disc at L5-S1.
The advantages of the standard open surgery over endoscopic discectomy for highly migrated disc or sequestrated disc herniation are the direct approach to the distal end of the migrated fragment and less risk of disc residue. However, compared with the conventional open surgery, PEILD offers several advantages such as normal paraspinal structure preservation, minimal postoperative pain, and lower risk of postoperative epidural scar formation and iatrogenic instability. Hence, if trajectory permits, ipsilateral PEILD is a safe option for an inferiorly migrated high-grade disc herniation at L5-S1.
| Conclusion|| |
This study achieved the good result through an interlaminar axillary endoscopic approach for high-grade L5-S1 disc herniation with inferior migration. Excellent results can be achieved without removal of the anterior facet, medial pedicle, and other anatomical structures, which is necessary for transforaminal approach targeting high-grade migrated disc. This can be a considerable option for the treatment of high-grade migrated ruptured discs that had previously been difficult to approach with a rigid endoscope.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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