MINISTRY OF EDUCATION AND TRANING MINISTRY OF HEALTH HANOI MEDICAL UNIVERSITY Specialism: Orthopaedic and Trauma Code: 62720129 MEDICAL DOCTORAL THESIS HA NOI - 2013 The thesis has been completed at: HANOI MEDICAL UNIVERSITY Supervisor: Ass prof NGUYEN CONG TO Ass prof NGUYEN VAN THACH Reviewer 1: Ass prof VU VAN HOE Reviewer 2: Prof LE DUC HINH Reviewer 3: Ass prof CAO MINH CHAU The Thesis will be present in front of board of university examiner and reviewer level hold at Hanoi Medical University At …………, on …… , 2013 The thesis can be found at: - National Library - National Medical Informatic Library - Library of Hanoi Medical University THE LIST OF WORKS RELATED TO THE THESIS THAT HAS BEEN PUBLISHED Dinh Ngoc Son, Nguyen Van Thach (2010),"A result of transforaminal endoscopic discectomy for lumbar disc herniation ", Vietnam Medical Journal, October, (2), pp 5-10 Dinh Ngoc Son, Nguyen Van Thach, Nguyen Thi Ngoc Lan, Nguyen Van Chuong, Pham Xuan Phong, Nguyen Le Bao Tien, Hoang Gia Du, Nguyen Hoang Long, Do Manh Hung (2011), "Summarize results of some methods in treatment of lumbar disc herniation ”, Vietnam Medical Journal 7/2011, pp 64-69 Nguyen Van Thach, Dinh Ngoc Son, Nguyen Le Bao Tien, Nguyen Hoang Long, Do Manh Hung, Dinh Manh Hai, Tran Quoc Khanh (2012), "Researching on applying device interspinous assisted motion into laminotomie to treat lumbar stenosis disease", Journal of surgery, 61(1, 2, 3), pp 351-356 Nguyen Van Thach, Dinh Ngoc Son, Nguyen Le Bao Tien, Hoang Gia Du, Nguyen Hoang Long, Tran Dinh Toan, Dinh Manh Hai, Do Manh Hung (2012),"Minimal invasive lumbar spine surgery: Treatment and outcomes", Journal of the Vietnam Orthopeadic Association, (1), pp 1-5 Dinh Ngoc Son, Nguyen Van Thach (2013), "Research on morphologic of the triangular working zone for the current practice of endoscopic lumbar discectomy through cadaver workshop”, Journal of the Vietnam Orthopeadic Association, (3), pp 31-35 INTRODUCTION The importance of the study Disc herniation refers to the displacement of disc material beyond the limits of the intervertebral disc space A herniated disc may engage the nucleus, the cartilage, the gristle, or annulous fibrosus A spinal specialist provides the definitive determination of the herniated disc position With the application of MRI today, it has become easier to find and classify a herniated disc Two methods of treating lumbar disc heniation include conservative treatment and surgical treatment Surgical treatment is laid out with a herniated disc causing nerve root compression or when conservative treatment fails after months Currently, in the world, open surgical procedure only applies to the case of large herniated disc and migrated disc herniation accompanied by other conditions of the spine such as spinal instability, spinal stenosis and alternative methods are minimally invasive discectomy Endoscopic surgery with access via a natural opening outside the spinal canal - the intervertebral foramen - to remove the herniated disc is a minimally invasive discectomy overcoming the disadvantages of posterior elements – the yellow ligament is not removed; it does not affect the rear part of the spine including the lamina, the spinal process, and the posterior longitudinal ligament; virtually no organized nerve fibers stick Endoscopic surgery is more favourable with distinctive features such as local anesthesia, small incision of 0.7 cm, 1-2 days in hospital after surgery, lower costs, and fewer complications According to some authors, the success rate is 85-95% However, this method can be only applied for lateral, foraminal and extra-foraminal herniation Endoscopy is commonly used in the U.S, Korea, Japan, Europe and has some applied anatomical research In Vietnam ,transforaminal endoscopic surgery is performed in the center of Saigon EXSon from 10/2007 and the Vietnam-Germany Hospital from 9/2008 In order to put a new method in practice, it is important to carry out the basic research, which is the applied anatomical research and using its results in clinical practice Therefore, “The applied research of endoscopic discectomy transforamen to treat lumbar herniated disc” is carried out with two goals: Identify the anatomical measurements through surgery on cadavers to determine the safety approach of transforaminal lumbar endoscopic discectomy Evaluate the results of transforaminal endoscopic surgery in lumbar herniated disc Practical values: The study shows the practical value of applied anatomical research to identify the safe access path in endoscopic surgery The study also shows the effectiveness of transforaminal lumbar endoscopic discectomy Contributions: - The first study of applied anatomy through the foramen in Vietnam, proposing some new points compared with previous studies in the world; it is the scientific basis for the implementation of the surgical method through the foramen - The first study in Vietnam on a new surgical method: transforaminal endoscopic discectomy Layout: The thesis consists of 149 pages, including: introduction (2 pages), overview (page 46), subjects and research methods (33 pages), results (35 pages), discussion (30 pages), conclusion (2 pages), proposal (1 page) Thesis has 45 tables, 82 images Reference materials in both Vietnamese and English Chapter OVERVIEW 1.1 APPLIED ANATOMY THROUGH THE FORAMEN * The foramen: the access path of endoscopic surgery + The intervertebral foramen is the aperture that gives exit to the segmental spinal nerves and entrance to the vessels and nerve branches that supply the bone and soft tissues of the vertebral canal It is superiorly and inferiorly bounded by the respective pedicles of the adjacent vertebrae Its ventral and dorsal components involve the two major intervertebral articulations The dorsum of the intervertebral disc, covered by the lateral expansion of the posterior longitudinal ligament, provides a large part of its ventral boundary, whereas the joint capsule of the articular facets and the ligamentum flavum contribute the major parts of its dorsal limitation Along with the root, the remaining space is filled with loose areolar tissue and fat + The internal structure of the foramen: nerve root, stem branch of the artery, the connection between the venous plexus TM inside and outside, the organization surrounding tissue structures Image 1.1 Foramen * The safety triangle: Dr Parviz Kambin defined this area as “a right triangle over the dorsolateral disc The hypotenuse is the exiting nerve root, the base (width) is the superior border of the caudal vertebra and the height is the dura/traversing nerve root.’ (Kambin P, Sampson S Clin Orthop Relat Res 1986 Jun; (207):37-43) In practice, approximately around the pedicle and disc are selected milestones identified in the surgical process because it is expressed on a fluorescent screen sang Understanding of the safety zone is important in entering the endoscope into a surgical field Image 1.2 and 1.3 The surgical triangle , (the safety triangle) A Hypotenuse B Inside edge C Dura/traversing nerve root D inferior edge E Pedicle slide F Safety triangle 1.2 CLINICAL 1.2.1 Clinical symptoms: - Spinal syndrome: back pain, scoliosis - Nerve root syndrome: pain, disorders of sensation along the dominant roots, reduced tendon reflexes, muscle atrophy - Irritation nerve root sign: good diagnosis * LassÌgue Test: Positive >60° * Pushing bell sign: pain along the leg * Valleix pain point: Using the thumb to push deeply on the points through the way of nerve root Patient can feel pain at the pushing points - Lesions of nerve root sign: disorders of sensation, moving, reduction of reflex, bladder disorder 1.2.2 Diagnostic imaging Conventional X-ray: Take lumbosacral spine straight, tilt left or right with three positions: lowered maximum, intermediate and maximum hyperextension; angling three quarters to the left or aim to eliminate damage loss strong, physically waist Computerized tomography (CT scan): to assess bone lesions suspected on X-ray, calcified discs Magnetic resonance imaging (MRI): the best diagnostic method available Classification by MRI: -By Fardon 2001: +Stage 1: Protrusion occurs when the outermost layers of the annulus fibrosus of the intervertebral discs are intact, but bulge when one or more of the discs are under pressure MRI vertical slices show that the distance between the edges of the disc herniation is less than the distance between the edges of the base +Stage 2: Extrusion occurs when the outer part of the spinal disc ruptures, allowing the inner, gelatinous part of the disc to squeeze out MRI vertical slices show the distance between the edges of the disc material is greater the distance at the base Image 1.4: Stage and Stage A : Protrusion B,C : Extrusion 11 lumbar using the surface rule and the Insize angle rule + The index relates exiting nerve root and superior facet join: The length indicates the suitability of endoscopic instruments * The distance from the inferior margin of the exiting nerve root to the superior margin of the spinous process at the coronal layer through superior face of vertebrae * The distance between anterisuperior facet join, the conection of superior facet join and pedicle to the inside edge of nerve root + Kambin triangle measurements: The hypotenuse, the base, the angle of the exiting nerve and the superior border of the caudal vertebra, and the height of the triangle + The index relates triangle through superior pedicle: inside edge, inferior edge and root-superior vertebral + Determine the area of two angles and compare to the circle slide through endoscopic instruments (Canule , tube) + The distance between two transverse nerve roots and the parallel line through the inferior vertebra 2.2.2 Clinical Study: a longitunal study to assess the outcomes of endoscopic surgery transforamen 2.2.2.1 Evaluation the clinical and MRI image of lumbar herniation - Evaluation the clinical: age, gender, onset symptoms… + Examination to find the lumbar-sacrum nerve root symtom + Caudal equinal syndrome: sphincter disorder - Diagnostic imaging: +Conventional X-ray: * Anterior-posterior and lateral X-ray: all patients * Moving X-ray: To exclude spinal instability, spondylolisthesis + CT scan: when bone damage is suspected 12 + MRI: applied to all of the patients *Determine herniation level: for example L34, L45… *Classify herniations: lateral, paramedian, and foraminal herniations *Classify herniations based on Lee SH’s zones: Near-migrated herniations: zones and 3; Far-migrated herniations: zones and *Herniation staging: Stage 1: protrusion, Stage 2: extrusion, Stage 3: migration, Stage 4: sequestration 2.2.2.2 Transforaminal endoscopic surgery -Instruments: Joimax endoscopic system, guide line system, canule, remove dics instrument, bleeding control tools -Patients: lying on the side with pillows supporting lumbar region -Surgical Procedures: Image 2.2 Endoscopic system Step 1: Determine the access Step 2: Put the needle inside the disc, check the disc by antiradiolucent Step 3: Open the incision Step 4: Widen the foramen Step 5: Put the canule Step 6: Enter the endoscope into the surgical field Step 7: Remove the herniation Step 8: Check the exiting nerve root and its mobility as well as patients’ clinical syndrom 13 Image 2.2.ABC The image of canule and instruments intraoperation 2A A-P film Midline of pedicle Anti-radiolucent inside the herniation 2C.Endoscopic image: Herniation Exiting nerve root 2.2.2.3 Outcome assessment -Pain level measured by VAS -Spinal dysfunction evaluation ODI -By modified Macnab criteria: +Excellent: No pain and no limitation of normal life +Good: Occasional pain or paresthesia, but no need of medication, and no limitation of normal life +Fair: Pain is somewhat improved but needs medication, and some limitation of normal life +Poor: No improvement or worsening, additional operation is needed due to incomplete decompression, development of instability -Postoperative MRI: -Complications: recorded -Recurrent hernia: not recorded as a complication 14 2.3 DATA PROCESSING: SPSS 13.5 2.4 ETHICS IN RESEARCH: The study information is confidential and serves the research purposes only Chapter RESEARCH RESULTS 3.1.RESULTS ON CADAVERS Table 3.1.The index relates the guide line of needle intraoperation: Anatomy index Mean SD Distance of the needle put inside edge of pedicle (mm) 64.24 21.542 Distance of the needle put middle edge of pedicle (mm) 48.38 14.257 Distance of the needle put outside edge of pedicle (mm) 35.42 10.560 The angle of inside edge pedicle needle (degree) 44.97 11.698 The angle of middle edge pedicle needle (degree) 57.08 10.531 The angle of outside edge pedicle needle (degree) 70.08 12.747 Distance between needle and exiting nerve root (mm) 1.85 0.964 Table 3.2 The index between exiting nerve root and superior facet joint Anatomy index Mean SD Distance between nerve root and outside edge of facet join (mm) 14.03 2.652 15 Distance between nerve root and anterior edge of facet join (mm) 6.77 1.599 Table 3.3 Kambin triangle measurements Kambin index Inside edge (mm) Inferior edge (mm) Height (mm) Nevre root - superior facet angle (degree) Triangle in area (mm square) Mean 16.55 12.59 9.66 52.48 107.08 SD 4.819 2.466 1.753 8.837 44.604 Table 3.4 The index relates the angle through superior pedicle Triangle of superior pedicle Mean SD Inside edge (mm) 19.20 5.041 Inferior edge (mm) 14.44 2.600 Height (mm) 11.66 1.812 Nevre root - superior facet angle (degree) 52.48 8.837 Triangle in area (mm square) 141.14 50.589 Table 3.5 Classify the triangle area due to the slide of endoscopic instruments Triangle Slide through canule (mm square) Slide through tube (mm square) S≤38.46 S≤44.15 S>38.46 S>44.15 N Rate N Rate N Rate N Rate Kambin 0.8% 119 99.2% 3.3% 116 96.7% Superior pedicle 0 120 100% 0 120 100% 3.2 CLINICAL OUTCOMES: 3.2.1.General characteristics: 16 -Gender: 52 males and 28 females Males/females is 1.85 -Age: 36.84 ± 12,02 on average The youngest is 19, and the oldest 71 -Past operative history: patients had past disc herniation operation 3.2.2.Clinical syndromes: -Spinal syndromes: 100% had mechanical back pain 26.5% spinal muscle spasm, 4.9% scoliosis - Nerve root syndrom Table 3.6 Lumbar sacrum nerve root syndrom Symptoms N Rate Lasseque sign positive 74 92.5% Oblique Lasseque sign 32 40% Touching bell sign 10% Valeix points system 10 12.8% Reduce or disappear the sensation base on nerve root 72 90% Reflex disorder: Patella tendon, heel 31 38.75% Moving disorder depend on nerve root 12 15% Nutrition disorders, amyotrophy 29 36.25% Radicular pain 79 98.75% Mean VAS leg pain 6.26 ± 1.202 3.2.3.MRI imaging: -Herniation level: L5S1: 43 patients (53.8%) L4L5: 36 patients (45%) L3L4: 01 patient -Location: Lateral : patients (11.3%), sub-articular : 61 17 patients (76.2%), foraminal: patients (10%), extra-foraminal: 02 patients (2.5%) -Herniation stage: Extrusion: 75 patients Migration: 05 patients 3.2.4.Surgical Treatment: -Surgical time: 99.7 minutes ±34.37 The longest is 250 minutes, and shortest 40 minutes -Difficulties: put the needle again:06 BN, put the canule again:02BN, difficult in drilling:02 BN, bleeding intra-operation: 01BN -In hospital: minimum 01 day, maximum 03 days Average: 02 days 3.2.5.Surgical outcomes: Table 3.7 VAS score before and after operation Preoperatio n 1-month follow-up 6-month follow-up 24-month follow-up N 80 80 79 65 Mean 6.3 2.96 2.04 1.23 1.195 1.427 0.953 1.057 53% 67.61% 80.47% VAS (score) SD Average improvemen t rate Table 3.8 ODI score before and after operation Preoperatio n 1-month follow-up 6-month follow-up 24-month follow-up 80 80 79 65 Mean (%) 60.58 33.20 19.35 10.49 SD 12.444 13.887 12.000 8.958 Time N 18 Average improvement rate 45.2% 68.1% 82.68% Table 3.9 ODI rate at different time pre and post operation ODI Preoperation (N) 1-month follow-up (N) 6-month follow-up (N) 24-month follow-up (N) Level 15 50 56 Level 46 26 Level 47 15 Level 26 0 Level 5 0 Total 80 80 79 65 Table 3.10 Outcome assessment based on Macnab criteria Macnab month follow-up N % >24 month follow-up N % Excellent 19 23.75 40 60.6 Good 58 72.5 21 31.8 Fair 2.5 6.1 Poor 1.25 1.5 Total 80 100 66 100 -Postoperative MRI: 29 patients taken One patient needed additional surgery due to recurrent disc herniation Two patients 19 needed follow-up on disc protrusion -Postoperative complications: Sensation disorders: patients (1.25%); Pseudocysts: 01/29 patients (3.5%) 01/80 -Recurrence: one patient needed additional surgery after months Chapter DISCUSSION 4.1 Result of cadaver research 4.1.1.Index relates approach of endoscopic surgery: - When the needle position is inside edge pedicle, the distance form starting point to midline: 64.24mm ±21.542 (Table 3.1) Depend on Kambin, The final position of needle is inside edge pedicle, The distance from starting point to midline is about 110-120 mm Yeung TA publish the general technique for all kind of hernation with the distance is about 120 ±20mm Our results are lower due to the smaller measeares of Vietnamese - When the needle is in middle of pedicle: The mean distance is about 48.38mm ±14.257 Theo Kim HD, fluctuate from 50-80mm - When the needle is in outside edge of pedicle: We think that the distance from exiting nerve root to annulus fibrous is mean about 1.85mm ±0.964 So with the 7mm canule we have 95% cases let to nerve root injury For that reason, we think that the distance safety for needle entry point is the mean distance between medial edge of pedicle and middle pedicle 4.1.2 The index relates exiting nerve root and superior facet joint -The distance from medial edge of nerve root and lateral facet 20 joint: Depend on table 3.2, The mean distance is 4.03mm± 2.652 So, it is easy for the procedure when the canule is 7mm and the tube is 5mm - The distance from anterior of superior facet join to exiting nerve root is about 6.77mm±1.599 This is the anatomy diameter when endoscopic instrument is used with migration herniation So with 8mm canule, we need to drill the foramen That is the most important point of endosopic transforamen technique 4.1.3.Kambin triangle: When the needle is parallel with the disc relate to the inferior triangle, and when the needle goes down, it relates to the height of triangle Depend on table 3.3, the length mean of inside edge is 16.55mm±4.819 and the height is 9.66mm±1.753, and also easy for 7.5mm instruments 4.1.4 Safety Kambin area and superior triangle compare with the slide of tube and canule: When compare with the slide of canule (table 3.5), we had a case with smaller area (0.8%) With 7.5mm tube, we had cases with smaller area (3.3%) But, all of triangle areas through superior pedicle are bigger than the slide of endoscopic instruments For that reason, we think that drilling facet join will help to easier touching to superior pedicle and easier for safety endocsopis systems 4.2.Clinical outcome: 4.2.1 Pain level measured by VAS: Table 3.7 shows the mean preoperative VAS score is 6.3 ± 1.19 with 95% falling between 5.05-6.69, the lowest score is and the highest The mean postoperative score is 2.96 ± 1.427; 2.04 ± 0.953 and 1.23 ± 1.057 at 1-month, 6-month, and 24-month follow-up respectively 95% confidence intervals are: 2.73-3.41; 1.8-2.32 and 1.12-1.63 There is a significant improvement in the VAS preoperation and postoperation (p