i low back ache under evaluation with ivdp l5 s1 ivdp

backache under evaluation

1. IVDP Dr Shinoj Saseendran Dept. of Orthopedic Surgery

2. Anatomy Disc composition Annulus fibrosis Composed of type I collagen, water, and proteoglycans 15-25 sheets of lamellae Characterized by extensibility and tensile strength High collagen / low proteoglycan ratio Nucleus pulposus Composed of type II collagen, water, and proteoglycans Characterized by compressibility Low collagen / high proteoglycan ratio Proteoglycans interact with water and resist compression A hydrated gel due to high polysaccharide content and high water content (88%) Disc height dependent on the degree of hydration  Avascular structure – nutrition by diffusion from end plates

3. Nerve root anatomy Key difference between cervical and lumbar spine is  pedicle/nerve root mismatch Cervical spine C6 nerve root travels under C5 pedicle (mismatch) Lumbar spine L5 nerve root travels under L5 pedicle (match) Extra C8 nerve root (no C8 pedicle) allows transition Horizontal (cervical) vs. Vertical (lumbar) anatomy of nerve root Because of vertical anatomy of lumbar nerve root a paracentral and foraminal disc will affect different nerve roots Because of horizontal anatomy of cervical nerve root a central and foraminal disc will affect the same nerve root

4. Epidemiology Peak incidence is 4th and 5th decades Lifetime prevalence of 10% Only ~5% become symptomatic 3:1 = male:female ratio L5/S1 most common level 95% involve L4/5 or L5/S1 levels

5. Pathoanatomy Recurrent torsional strain leads to tears of the outer annulus which leads to herniation of nucleus pulposis Lateral edge of posterior longitudinal ligament weakest region - common site for posterolateral / paracentral disc herniations Sinuvertebral nerves provide pain innervation to posterior annulus Mediate vertebrogenic back pain that precedes or accompanies disc herniation  

6. Pathophysiology Cellular senescence of fibrochondrocytes leads to loss of proteoglycan production leading to disc height loss  Loss of height causes increased strain on the annulus fibrosus Increased strain leads to fissures of the annulus fibrils  Nucleus pulposus herniates through tear Younger, well-hydrated discs more likely to herniate Older, desiccated discs less likely to herniate Sciatica symptoms result from combined mechanical compression and associated inflammation Not all patients with mechanical compression develop symptoms 

7. Classification Location Central prolapse Often associated with back pain only May present with cauda equina syndrome which is a surgical emergency Posterolateral ( paracentral )  Most common (90-95%) PLL is weakest here Affects the traversing/descending/lower nerve root   At L4/5 affects L5 nerve root  Foraminal (far lateral, extraforaminal )    Less common (5-10%) Affects exiting/upper nerve root   At L4/5 affects L4 nerve root 

8. Morphology Protrusion Eccentric bulging with an intact annulus Extrusion Disc material herniates through annulus but remains continuous with disc space Sequestered fragment (free) Disc material herniates through annulus and is no longer continuous with disc space Prone to proximal or distal migration Containment Contained  Disc material is contained beneath the posterior longitudinal ligament Uncontained Disc material passes dorsal to the posterior longitudinal ligament

9. Timing Acute Herniations present < 3-6 months Chronic Herniations present >6 months

10. Presentation History Sudden onset of pain after lifting a heavy object Prolonged sitting with lateral bending and rotation in the presence of vibrational energy Symptomatic improvement lying supine with knees and hips flexed Especially with lower lumbar disc herniations Symptoms  Axial back pain (low back pain) May be discogenic or mechanical in nature Can precede herniation   Radicular pain (buttock and leg pain) Often worse with sitting, improves with standing Symptoms worsened by coughing, valsalva , sneezing etc.

11. Cauda equina syndrome (present in 1-10%) Bilateral leg pain Saddle anesthesia Bowel/bladder symptoms

12. Physical examination  Inspection Limited lumbar range of motion Often the pain is the limiting factor Patient leaning away from side of radiculopathy Effort to increase the size of the neuroforamen Palpation Spasms of the paraspinal musculature Nonspecific Associated tenderness in the paraspinal musculature  

13. Motor exam & reflexes L3 radiculopathy Hip adduction weakness   Knee extension weakness Dermatomal pain in the anteromedial thigh L4 radiculopathy   Ankle dorsiflexion weakness (L4 > L5) Decreased patellar reflex Dermatomal pain in the lateral thigh, crossing the knee, to medial foot

14. L5 radiculopathy EHL weakness (L5) Ankle dorsiflexion weakness (L4 > L5 contribution) Test by having patient walk on heels Ankle inversion weakness   Hip abduction weakness (L5)   Have patient lie on side on exam table and abduct leg against resistance Dermatomal pain in anterolateral leg and dorsum of foot   S1 radiculopathy Ankle plantar flexion weakness (S1) Have patient do 10 single leg toes stands Decreased achilles tendon reflex Dermatomal pain in posterior calf and lateral foot

15. Provocative tests Straight leg raise ( lasegue's sign) A tension sign for L4, L5 and S1 nerve root Can be done sitting or supine Reproduces pain and paresthesia in leg at 30-70 degrees hip flexion Contralateral SLR Crossed straight leg raise is less sensitive but more specific Femoral nerve stretch test Tension sign for L2 and L3 Performed in prone position Knee flexed and hip extended Reproduction of pain in anterior thigh is considered positive

16. Braggard's sign Perform SLR to the point of exacerbation Lower leg just to the point where pain recedes Ankle dorsiflexion causes exacerbated pain Bowstring sign SLR aggravated by compression on popliteal fossa Gait analysis Trendelenburg gait Due to gluteus medius weakness which is innervated by L5

17. Lower Extremity Spine and Neuro Exam Nerve root Primary Motion Primary muscles  Sensory Reflex L1 Iliac crest and groin  Cremasteric reflex  (L1 and L2) L2 Hip flexion and adduction Iliopsoas (lumbar plexus, femoral n.) Hip adductors (obturator n.) Anterior and inner thigh  Cremasteric reflex  (L1 and L2) L3 Knee extension ( also L4 ) Quadriceps (femoral n.) Anterior thigh, medial thigh and medial knee  - L4 Ankle dorsiflexion ( also L5) Tibialis anterior (deep peroneal n.) Lateral thigh, anterior knee, and medial leg  Patellar L5 Foot inversion Toe dorsiflexion Hip Extension Hip abduction Tibialis posterior (tibial n.) EHL (DPN), EDL (DPN) Hamstrings (tibial) & gluteus max (inf. gluteal n.) Gluteus medius (sup. gluteal n.) Lateral leg & dorsal foot  - S1 Foot plantar flexion Foot eversion Gastroc-soleus (tibial n.) Peroneals (SPN) Posterior leg  Achilles S2 Toe plantarflexion FHL (tibial n.), FDL (tibial) Plantar foot  - S3 & S4 Bowel & bladder function Bladder Perianal  -

18. Radiographs AP and lateral radiographs Flexion-extension - identifies instability Abnormal findings Loss of lordosis (spasm)  Loss of disc height  Lumbar spondylosis (degenerative changes) Facet hypertrophy Disc space collapse Peridiscal osteophytes Sciatic scoliosis More often used as a screening tool for other pathology prior to proceeding with MRI

19. CT myelogram   Patients unable to obtain MRI  Pacemaker MRI without gadolinium Pain lasting > one month and not responding to nonoperative management  or    Red flags are present Infection (IV drug user, h/o of fever and chills) Tumor (h/o or cancer) Trauma (h/o car accident or fall) Cauda equina syndrome (bowel/bladder changes) Modality of choice for diagnosis of lumbar disc herniations Highly sensitive and specific Helpful for preoperative planning

20. Treatment Nonoperative Rest and physical therapy, anti-inflammatory medications, and limited narcotics    First line of treatment for most patients with disc herniation New-onset radicular pain No significant motor weakness Absence of cauda equina syndrome No bowel/bladder incontinence 90% improve without surgery

21. Selective nerve root corticosteroid injections    Second line of treatment if therapy and medications fail Usually after 6 weeks Leads to long lasting improvement in ~ 50% (compared to ~90% with surgery) Results best in patients with extruded discs as opposed to contained discs No difference in pain relief using lidocaine with and without steroids

22. Operative Laminotomy and discectomy  ( microdiscectomy ) Far lateral microdiskectomy   Stabilization  

23. Summary Lumbar Disc Herniation is a very common cause of low back pain and unilateral leg pain, known as radiculopathy . Diagnosis is made clinically and confirmed with an MRI studies of the lumbar spine. Treatment for radicular leg pain is initially non-operative with oral medications and physical therapy.  Surgical microdiscectomy is indicated for severe pain and/or motor deficit that have failed to respond to non-operative management. Treatment for Cauda Equina Syndrome in contrast is emergent microdiscectomy within 48 hours.