25. Low Back Pain

Paracentral extrusion affects which nerve root?

*Descending* nerve root (ex: btwn L4 & L5 → affects L5)

Foraminal extrusion affects which nerve root?

*Exiting* nerve root (ex: btwn L4 & L5 → affects L4)

Radiculopathy sx?

- LMN dysfunction (affects nerve roots as they exit the spinal cord) - Weakness - Hyporeflexia

Myelopathy sx?

- UMN dysfunction (affects the spinal cord itself) - Hyperreflexia - Loss of coordination - Clonus (spasticity)

A 35-year-old construction worker is brought to the emergency department following a fall from a significant height at a construction site. He landed on his feet, and immediately after the fall, he experienced severe mid-back pain. On examination, the patient is found to have tenderness over the thoracic spine, and there is noticeable paraspinal muscle spasm. Neurological examination reveals weakness in the lower extremities, with decreased sensation and reflexes. An urgent CT scan of the thoracic spine is performed, showing a fracture involving the vertebral body with *retropulsion* of bony fragments into the *central canal*, and involves the *middle column*.

Burst fracture

A 40-year-old man presents to the emergency department with sudden-onset severe low back pain. He reports associated numbness in the *perianal region* and bilateral *radicular leg pain*. He mentions *difficulty initiating urination* and recalls a recent episode of *fecal incontinence*. On examination, there is *profound weakness* in ankle dorsiflexion and plantarflexion bilaterally, and he has *absent ankle reflexes*. The perianal sensation is markedly reduced, and there is *laxity of the anal sphincter* on digital rectal examination. Urgent MRI of the lumbar spine reveals a *large herniated disc* at the L4-L5 level. Tx?

Cauda equina syndrome Tx? Urgent/emergent surgical decompression

A 55-year-old man presents to your clinic with complaints of progressive *weakness and clumsiness* in his hands. He has noticed a gradual deterioration in handwriting and frequent dropping of small objects. Additionally, he reports difficulty with *balance, occasional tripping*, and a feeling of stiffness in his legs. On examination, you observe *hyperreflexia* in the upper and lower extremities, with sustained *clonus* at the ankles. There is also bilateral hand clumsiness, impaired fine motor skills, and brisk deep tendon reflexes in the upper limbs. An MRI of the cervical spine reveals multilevel degenerative changes with spinal cord compression, particularly at the *C5-C6* level.

Cervical myelopathy

A *70-year-old postmenopausal* woman presents to the emergency department with a complaint of sudden-onset mid-back pain. She reports that the pain began after she slipped and fell in her kitchen earlier in the day. The pain is localized to the thoracic spine and *radiates around her ribs*. On exam, there is tenderness over the thoracic spine, and she winces with palpation. Neurological examination reveals no focal deficits, and the patient is able to ambulate without difficulty. An X-ray of the thoracic spine is obtained, which shows a *wedge-shaped* deformity involving one of the thoracic vertebrae. Dx? Tx?

Compression / Wedge Fracture Dx? XR usu sufficient Tx? No complications → observation, bracing. Persistent pain or other dysfunx → operative (kyphoplasty, vertebroplasty, or decompression.)

Degrees of abnormal curvature and when to monitor?

Curvature > 50º → usu progresses Closely monitor anything > 15-20º

A 50-year-old office worker presents to your clinic with complaints of *chronic low back pain* that has been progressively worsening over the past few years. She describes the pain as dull and achy, primarily localized to the lower back, with intermittent radiation down the back of her right thigh. The pain is *exacerbated by prolonged sitting and bending*, and she notes some relief when lying down. On exam, there is tenderness over the lumbar spine, and the patient exhibits reduced lumbar spine flexibility. *Neuro examination is unremarkable*, with *no signs of radiculopathy*. Imaging studies, including X-rays and an MRI, reveal *disc space narrowing* at the L4-L5 level with evidence of degenerative changes such as disc desiccation and the presence of osteophytes.

Degenerative Disc Disease

A 55-year-old man with a history of diabetes mellitus and recent dental procedures presents to your office with complaints of severe back pain over the past few weeks. He describes the pain as constant, localized to the lower back, and exacerbated by movement. The pain is not relieved with over-the-counter analgesics. On examination, there is tenderness over the lower lumbar spine, and the patient is reluctant to move due to pain. He denies any recent trauma or fever. Laboratory tests reveal an elevated ESR and CRP. MRI of the lumbar spine shows disc space narrowing, vertebral endplate erosions, and increased signal intensity in the affected disc.

Discitis

A 60-year-old male with a history of *intravenous drug use* presents to the emergency department with a two-day history of *severe back pain and fever*. He reports progressive *weakness and numbness* in his lower limbs, and on examination, there are signs of bilateral lower extremity weakness and loss of sensation below the *T10* level. The patient also mentions recent skin abscesses on his arms. Laboratory studies show an elevated white blood cell count and an increased CRP.

Epidural Abscess

35-year-old woman presents to your clinic with complaints of acute lower back pain that *radiates* down her right leg. She reports that the pain started suddenly after *lifting a heavy box* at work. The pain is sharp and shooting, following the path from her lower back *down to the back of her right thigh and into her calf*. She notes *tingling* sensations and occasional *numbness* in her right foot. On examination, there is tenderness over the lower lumbar spine, and straight leg raising reproduces the pain and tingling sensations along the right leg. Her pain is *worse with flexion* and *relieved with extension*. Neurological examination reveals weakness in ankle plantarflexion and decreased sensation in the S1 dermatome on the right side. Tx?

Herniated disc Tx? Conservative if no red flags or motor weakness. Surgery if neuro sx or no improvement

Central extrusion affects which nerve root?

If at level of a spinal cord: various effects Below conus medularis: LMN effect, affect more centralized nerve roots - Ex: if L4/L5, unlikely to effect L5 but could compress sacral roots

What type of curvature? Hump/hunchback, increased convexity of thoracic curvature

Kyphosis

What type of curvature? Swayback, exaggeration of normal lumbar curvature

Lordosis

Tx of Non-specific LBP

NSAIDs, education, posture, stretching, PT, ice therapy Resolves w/i 4-6 wks

A 12-year-old boy is brought to the emergency department by his parents due to complaints of severe pain in his right leg. The parents report that the pain started insidiously a few days ago, and the child is now refusing to bear weight on the affected limb. On examination, the boy *appears ill*, and there is localized tenderness, warmth, and swelling over the proximal right tibia. He has a low-grade fever, and blood tests show an *elevated white blood cell count*. X-rays reveal lytic changes and *periosteal* reaction in the proximal tibia.

Osteomyelitis (pyogenic)

S1 dermatome?

Pain in lateral leg and foot Motor weakness in plantarflexion of great toe & foot (peroneus longus & brevis) Reflex? Achilles reflex (ankle jerk diminished)

L4 dermatome?

Pain in medial calf & foot, and big toe Motor weakness in extending quads Reflex: patellar reflex

L5 dermatome?

Pain in top of foot, anterolateral calf Motor weakness in dorsiflexion of great toe & foot (extensor hallucis longus) Reflex? None

A 45-year-old male presents to your office with complaints of sharp, shooting pain and *numbness radiating* down his left leg. He reports that the pain *originates in his lower back* and travels down the back of his thigh and into the calf. The patient mentions that coughing or sneezing exacerbates the pain, and he occasionally experiences tingling sensations and *weakness* in the affected leg. Physical examination reveals decreased sensation in the L5 dermatome and *weakness in ankle dorsiflexion*. Straight leg raising test reproduces the pain along the lateral aspect of the left leg.

Radiculopathy / Radicular pain

What type of curvature? Lateral curvature of spine, rotational component

Scoliosis

A 45-year-old immigrant from a *tuberculosis-endemic region* presents to your clinic with complaints of back pain and stiffness that have been progressively worsening over the past few months. He reports unintentional weight loss and occasional night sweats. On examination, there is tenderness over the *lower thoracic and upper lumbar spine*. The patient demonstrates a reduced range of motion and there is visible *kyphosis*. Neurological examination is unremarkable. Chest X-ray reveals apical lung infiltrates, and an MRI of the spine shows vertebral destruction and paravertebral abscess formation.

Spinal TB (Pott Disease)

A 65-year-old male presents to your office with complaints of *bilateral* leg pain and numbness that worsens with walking. He describes the pain as crampy and aching, mainly located in his thighs and buttocks. The symptoms typically start after *walking* for a few minutes and are *relieved by rest or forward bending*. Over the past several months, he has noticed a decrease in his ability to walk longer distances, and often has to *lean on his cart* while shopping. On exam, there is no significant back pain, and neurologic exam reveals no weakness. The patient demonstrates a stooped posture while walking. Imaging studies, including an MRI of the lumbar spine, show significant *degenerative changes* with disc bulging and ligamentous hypertrophy.

Spinal stenosis

A 55-year-old male presents to your primary care clinic with complaints of chronic low back pain that has been bothering him for the past several months. He describes the pain as dull and achy, primarily concentrated in the lower back. The pain is *worse in the morning*. There is no history of trauma or recent injuries. On examination, there is reduced lumbar spine flexibility, and the patient experiences discomfort during lumbar extension. Neurological examination is unremarkable, with no signs of radiculopathy. Imaging studies, including X-rays and MRI, reveal *degenerative changes* in the *intervertebral discs*.

Spondylosis (local arthropathy)

A *30*-year-old woman presents to your neurology clinic with complaints of *progressive loss of sensation* and weakness in her hands. She reports that the symptoms have been *developing gradually* over the past few years. On examination, you note muscle atrophy in the hands, particularly involving the intrinsic muscles. On exam, you notice that her *arms are weaker than her legs*. Deep tendon reflexes are normal. An MRI of the cervical spine shows a *fluid-filled cavity within the spinal cord* extending from the cervical to the thoracic region.

Syringomyelia