1	"John C" John C. Chiu, M.D., FRCS (US), D.Sc. Chief, Neurospine Surgery California Spine Institute Thousand Oaks, California, USA President, ISMISS/SICOT
2	Overview: This presentation is to demonstrate the minimally invasive spinal surgery (MISS) of minimally invasive spinal technique (MIST) for treatment of post spinal fusion - junctional disc herniation syndrome (JDHS) or adjacent segmental disease (ASD) To preserve spinal segmental motion
3	Introduction: The biomechanical alteration, additional mobility and stress placed on intervertebral segments adjacent to fused cervical and lumbar spinal segments, resulting in degeneration and protrusion of adjacent discs, i.e. Post Spinal Fusion - Junctional Disc Herniation Syndrome (JDHS) or adjacent segmental disease (ASD) Its incidence is 25 to 40% of post fusion cases, within four years At times such degenerative herniated JDHS can proceed up or down the spine from an original level to eventually total four or five levels, especially at cervical spine and also at lumbar spine
4	Materials and Methods: A series of 300 patients (436 discs) with JDHS; 178 males, 122 females 59% cervical, 41% lumbar post fusion occurrence of JDHS Aged 38 to 77; average 47.8 Interval to occurrence – 6 months to 11 yrs (average 4.1 yrs) All were treated with endoscopic microdecompressive spinal discectomy and laser thermodiskoplasty
5	Indications: Post ACF fusion C4 – C6 JDHS MRI showing junctional discs at C3-4 and C7-T1 Anterior endoscopic cervical microdiscectomy (AECD) provides relief
6	Indications:
7	Surgical Instruments and Equipment: Video digital endoscopy tower and spinal endoscopic instruments
8	Materials and Methods: Familiarity and experience in the use of various endoscopic surgical systems including, Spinoscope (Storz) and CMIS transforaminal decompressive tubular system To facilitate endoscopic spine surgery To avoid potential complications
9	Materials and Methods:
10	Surgical Instruments and Equipment: Including Holmium YAG laser digital equipment for Laser Thermodiskoplasty (LTD), radiofrequency, and others
11	Surgical Instruments and Equipment: Continuous intra-operative EMG monitoring prevents undue trauma to the spinal nerve to be decompressed Continuous conscious EEG monitoring with the newest computerized SNAP device (SNAP index) improves anesthesia and reduces drug requirement
12	Surgical Procedure/Technique: To facilitate endoscopic spine surgery
13	Surgical Procedure/Technique: MISS decompression of spinal canal with various approaches With posterolateral (transforaminal) approach for lateral stenosis - PLLD With paramedium approach for lateral and central stenosis – TSLD With paraspinal approach - PSpLD With cross canal decompression - CCDF
14	Surgical Procedure/Technique: The patient is positioned in lateral decubitus position if unilateral and prone for bilateral approach The dilator and then a duck bill tubular retractor/cannula are passed over the stylette Foraminoplasty and decompressive discectomy performed with trephines, forceps, discectome and Holmium laser
15	Surgical Procedure/Technique:
16	Surgical Procedure/Technique: Endoscopic lumbar discectomy with lumbar nerve root in close proximity
17	Surgical Procedure/Technique: The bendable tip in situ
18	Surgical Procedure/Technique: Anterior endoscopic cervical microdiscectomy technique for anterior medial approach for needle and stylette placement into the disc
19	Surgical Procedure/Technique: Mechanical discectomy decompression Forceps, discectome, trephine under fluoroscopy
20	Surgical Procedure/Technique: Endoscopic microdiscectomy – intraoperative video recording
21	Surgical Procedure/Technique: Surgical technique of LTD, fan sweep maneuver and endoscopic views of disc shrinkage
22	Surgical Procedure/Technique: Absorbed by water A pear shaped cavitation bubble formed by vaporization of water molecules, undergoes expansion and collapse - resulting in acoustic and shock wave emission Simultaneously a vapor channel is formed that effectively conducts laser energy to the target “MOSES EFFECT” Requiring continuous irrigation and open channel for release of vaporized bubbles and secondary pressure
23	Surgical Procedure/Technique:
24	Surgical Procedure/Technique: Minimally invasive spine surgery (MISS) offers a method of treatment for these protruded discs MISS does not require reopening an old wound, wide dissection of muscle, scar tissue and bone, or further bone grafting
25	MISS Decompression of Neuro Foramen in JDHS MISS is to avoid morbidity associated with open lumbar spinal surgery and can be performed in IV conscious state Posterior lateral transforaminal technique can visualize and treat extra foraminal, foraminal, and lateral recess pathology, related to JDHS Interpretation of endoscopic findings of foraminal surgical anatomy and avoidance of trauma to the dorsal root ganglion are of prime importance in treatment
26	Neuro-foraminal Surgical Anatomy: It is a tubular 3D structure Four zones: lateral recess (osteum internum), the pedicle zone (mid- zone), exit zone (osteum externum) and far lateral zone Internal zone of the foramen: the superior notch, inferior notch and sub-articular zone (bonded by disc and facet joint) Success or failure for endoscopic surgical procedure depends on the dynamics on the foraminal size, shape and contents
27	Neuro-foraminal Surgical Anatomy: The pedicles, facet joints, intravertebral disc, and the vertebra These border the foramen which is endoscopically divided into three zones: Superior notch (from the junction of proximal tip of superior facet to the posterior margin of vertebral body of superior vertebra) Sub-articular zone (ventral to the facet joint and disc) Inferior notch (caudal to an imaginary line projecting posteriorly from the superior margin of the inferior vertebral body to the ascending articular process
28	Neuro-foraminal Surgical Anatomy: Intervertebral disc with degenerative changes and reduction in height and secondary disc bulge or protrusion Spinal ligaments Ligamentum flavum Joint capsule Posterior longitunal ligamen Pathophysiology of hypertrophic ligaments
29	Neuro-foraminal Surgical Anatomy: Intraspinal neuro structures – lig attachments: Midline ligament (Hofmann) Lateral ligament (Hofmann) Lateral root ligament Neural attachments The lateral root ligament Foraminal complex Transforaminal ligaments (superior, intermedial, inferior types) and the corporotransverse ligaments (seldom recognized endoscopically) Patho genesis of hypertrophic ligaments with secondary structural compression
30	Neuro-foraminal Surgical Anatomy: Anterior intervertebral venous plexus (AIVVP) which receive basi vertebral veins, avoiding the disc and also runs in the lateral gutter of the spinal canal Posterior internal vertebral venous plexus (PIVVP) in the epidural space posteriorly and traversing adjacent segments, reaching out through the foramen into external venous plexus and lateral longitudinal intravertebral venous plexus The segmental artery supplies anterior longitudinal arterial system of the epidural space anterior to PLL Connected to posterior longitudinal arterial system
31	Neuro-foraminal Surgical Anatomy: Three types of arterial supply to the spinal nerves: Radiculomedullary a. Radicular arteries T-shape branches of articular artery
32	Neuro-foraminal Surgical Anatomy: Segmental nerve supply to the spine – ascending facet branch, ascending sinu vertebral (SV), SV branch of facet, descending facet branch, branch to disc, gray ramus, and branches to all, and posterior primary ramus Autonomic nervous system – sympathetic chain, related to sympathetic back pain Lumbar dura – by sympathetic system
33	Neuro-foraminal Surgical Anatomy: Dorsal root ganglion in the superior notch – substance P. L4 and L5 DRG locates intra foraminally, while L1 to L3 , and S1 DRG intraspinally Spinal content Several membranes have been identified Internal vertebral nerve supplies Recurrent meningeal nerve Communicating filaments Sacral Iliac Joints Nerve supplies from L4-S3 inclusive
34	Neuro-foraminal Surgical Anatomy: Degenerative spondylolisthesis may compromise the foramen causing compression of exit nerve root Bony overgrowth may occur: Diffuse idiopathic skeletal hyperostosis (Dish) Paget's disease Ankylosing spondylosis Acromegaly Hyperparathyroidism Fluorosis
35	Neuro-foraminal Surgical Anatomy: Foraminal and lateral recess stenosis may result from foraminal narrowing caused by: Disc herniation Dish Synovial cyst or tumor Spondylolisthesis Subarticular lateral recess stenosis due to facet hypotrophy, Dish, and Paget’s disease
36	Neuro-foraminal Surgical Anatomy: From any bony margins of spinal foramen and spinal canal Endoscopically the lesions and deviation of exiting nerve are visualized Shoulder osteophytes often displace the nerve medially or laterally and the nerve is often found adherent to them Facet and lamina hypertrophy causing spinal stenosis Transforaminal ligament of Hofmann may cause pain Calcified ligaments causing compression of the nerve during spinal movements Superior foraminal ligament, can be classified requiring decompression for foraminoplasty
37	Neuro-foraminal Surgical Anatomy: Spondylolisthesis – anterior or retro Neural anomalies: Conjoined nerve in 14% Claudication: Secondary to spinal stenosis
38	Neuro-foraminal Surgical Anatomy:
39	Neuro-foraminal Surgical Anatomy:
40	Discussion and Comment: The success of endoscopic MISS for treatment of JDHS depends on careful analysis of all factors causing pain Causation (inter related factors) of pain and sciatica are: Mechanical and physical factors Tissue changes – neo-vascularisation and neo-neuralisation Biochemical factors: cytokines, pain mediators, alteration in PH, ionic changes etc… Endoscopic MISS surgeon needs to consider the effect of JDHS alteration of the foraminal anatomy in order to treat the pathology effectively
41	Post Operative Care: Ambulatory within one hour and discharged subsequently May shower the following day May use a cervical collar in a vehicle or on a flight as needed (cervical discectomy) Ice pack is helpful Mild analgesics and muscle relaxant are required at times Progressive spine exercise second post operative day on Allowed to return to work in one to two weeks, provided heavy labor and prolonged sitting are not involved
42	Post Operative Care: At CSI before and after MISS for post-op care A physical medicine and rehabilitation unit with computerized assistance Motorized pool and hydro therapy equipped with video camera for monitoring and assessment
43	Result:
44	Discussion: MISS can treat the problem of Post Spinal Fusion - Junctional Disc Herniation Syndrome (JDHS) or Adjacent Segmental Disease (ASD), as an outpatient procedure with ease and with segmental motion preservation No likelihood of a similar progression of future disc protrusions as in post Spinal Fusion - JDHS or ASD
45	Conclusion: Minimally invasive spinal surgery (MISS) of minimally invasive spinal technique (MIST) is the treatment of choice over spinal fusion and instrumentation, for all post spinal fusion - JDHS or ASD above or below the fusion segment It is an outpatient procedure performed with ease and efficacy Best of all, it preserves the spinal segmental motion
46	Hope you enjoyed this presentation!