lower back and leg pain approaches

lower back and leg pain approaches

1. Bradly 2016 32: Lower Back and Lower Limb Pain

2. ANATOMY AND PHYSIOLOGY * The lumbosacral spinal cord terminates in the conus medullaris at the level of the body of the L1 vertebra * The motor and sensory nerve roots from the lumbosacral cord form the cauda equina . From there, the motor and sensory nerve roots unite at the dorsal root ganglion to form the individual spinal nerves . * These anastomose in the lumbosacral plexus from which run the major nerves supplying the leg * Pain in the lower back can have many origins. A good beginning for the differential diagnosis is determining whether the leg also has pain. * A complicating factor in this consideration is that local spine pain can be referred—that is, felt at a distance—because of the common nerve root innervation of the proximal spinal nerves and peripheral nerves supplying distal parts of the leg.

3. # Causes of lower back pain without leg pain include : • Ligamentous strain • Muscle strain • Facet pain • Bony destruction • Inflammation # Causes of lower back plus lower limb pain include: • Radiculopathy • Plexopathy # Important causes of leg pain without low back pain include : • Sciatic neuropathy • Femoral neuropathy • Peroneal neuropathy • Meralgia paresthetica • Peripheral polyneuropathies

4. * Isolated tibial neuropathy is uncommon. * Individual peripheral nerve lesions usually are caused by local trauma , entrapment by connective tissue, or involvement with mass lesions . # Lower back pain caused by non-neurological and nonskeletal lesions are : • Urolithiasis • Ovarian cysts and carcinoma • Endometriosis • Bladder or kidney infection • Abdominal aortic aneurysm • Visceral ischemia or other aortic ischemic disease.

5. History and Examination Focus first on • Mode of onset • Character • Distribution • Associated motor and sensory symptoms • Bladder and bowel control • Exacerbating and remitting factors • History of predisposing factors (e.g., trauma, cancer, osteoporosis ) * The acute onset of lower back pain radiating down the leg suggests a lumbosacral radiculopathy . * Onset with exertion suggests a herniated disk as a cause of the radiculopathy. * Progressive symptom development can be from any expanding lesion, such as a tumor, infection, or expanding disk extrusion.

6. # Muscle groups that can be tested include: 1- Hip–girdle muscles : • Hip flexors (psoas, sartorius ) • Hip extensors (gluteus maximus , semitendinosus, semimembranosus, biceps femoris ) • Hip adductors (adductor group: longus , brevis , magnus ) • Hip abductors (gluteus medius , gluteus minimus , piriformis ) 2- Knee muscles: • Knee extension (quadriceps) • Knee flexion ( semitendinosus , semimembranosus , biceps femoris ) 3- Ankle and foot muscles: • Foot plantar flexion (gastrocnemius) • Foot dorsiflexion ( tibialis anterior) • Foot everters (peronei) • Foot inverters ( tibialis posterior) • Toe extension (extensor digitorum ) • Great toe extension (extensor hallucis longus ) • Toe plantar flexion (flexor digitorum longus ) • Great toe flexion (flexor hallucis longus )

7. # Sensory examination should include the important nerve roots and peripheral nerve distributions: the femoral , peroneal , tibial , and lateral femoral cutaneous , lumbar roots L2– L5 , and sacral root S1 . # Reflexes to be studied include the Achilles , patellar , and plantar reflexes . * Exacerbation of pain with some maneuvers also can be revealing. * Stretch of damaged nerves results in increased pain by deforming the axon membrane, thereby increasing membrane conductance, depolarizing the nerve, and producing repetitive action potentials. * Straight leg raising augments pain in a lumbosacral radiculopathy . * Hip extension exacerbates pain of upper lumbar radiculopathy or that due to damage to the upper parts of the lumbar plexus, such as from carcinomatous infiltration or inflammation.

8. # Differential Diagnosis of Lower Back and Leg Pain * Some basic guidelines : • Pain confined to the lower back generally is caused by a low back disorder . • Pain confined to the leg usually is caused by a leg disorder, although neuropathic pain from lumbar spine disease can radiate down the leg without back pain in a minority of patients. • Pain in both is caused by lumbar radiculopathy or, less commonly, lumbosacral plexopathy . • Clinical abnormalities confined to one nerve root distribution usually are caused by intervertebral disk disease or lumbosacral spondylosis producing radiculopathy .

9. • Clinical abnormalities that involve several nerve distributions usually are caused by plexus lesions , with cauda equina lesions being the alternative diagnosis . • Bilateral lesions suggest proximal damage in the spinal canal affecting the roots of the cauda equina . • Impairment of bladder control indicates either a cauda equina lesion or, less commonly, a bilateral sacral plexopathy • Multiple lesions can make the differential diagnosis more difficult. For example, radiculopathies at two or more levels may look like a plexopathy or peripheral neuropathic process.

10. # Non-neurological causes of lower back pain : 1- Urolithiasis 2- Ovarian cysts 3- Endometriosis 4- Pelvic carcinoma 5- Bladder infection 6- Other retroperitoneal lesions including tumor, abscess , abdominal aortic aneurysm, visceral ischemia, and hematoma . * These conditions produce pain that does not radiate unless neural structures are involved. * Neural involvement in the abdomen and pelvis can produce radiating pain that can be clinically differentiated from radiculopathy only if multiple nerve roots are involved. * Early involvement of bowel or bladder function together with abdominal pain suggests one of these non-neurological conditions .

11. Evaluation 1- Magnetic Resonance Imaging * to assess the lumbosacral spine and lumbosacral plexus . * It also can be used to evaluate the peripheral nerves in the pelvis and lower limbs. * Intraspinal disorders that may not be revealed by MRI without contrast enhancement include neoplastic meningitis, epidural abscess, diskitis , and some chronic infectious meningitides 2- Myelography and Postmyelographic Computed Tomography * If adequate information is not obtained from noninvasive studies, myelography occasionally may be indicated. * Postmyelographic computed tomography (CT ) is performed in most instances.

12. 3- Nerve Conduction Studies and Electromyography They are performed for four principal purposes : • Assist localization of the lesion(s) • Assist in evaluating the severity of the lesion(s) • Determine whether the lesion is acute, subacute , or chronic • Determine whether the lesion is neuropathic, axonal, or Demyelinating * Axonal damage seen with radiculopath y or entrapment neuropathy suggests consideration of surgical decompression. * Signs of denervation may not appear on EMG until up to 4 weeks after onset of axonal damage.

13. * Entrapment neuropathy , or nerve root compression which can be responsible for lower limb pain, is likely to slow conduction velocity across the region of compression. * Conduction velocities proximal and distal to the compression usually are normal, so conduction across the affected nerve segment must be studied . * Radiculopathy typically is associated with normal NCS findings in the peripheral branches of the nerves but with slowing of the F-wave. * Absence of abnormalities on NCSs and EMG does not rule out the presence of a radiculopathy . * Mechanical lower back pain is associated with no EMG or NCS alterations ,

14. 4- Radiography Among the potential findings are degenerative joint disease , vertebral body collapse , bony erosion , subluxation , and fracture . 5- Bone Scan *Bone scan is especially important for examining multiple bone regions in cases of suspected neoplastic bone involvement . * Multifocal involvement makes a neoplastic cause more likely than an infectious cause for the destruction.

15. # CLINICAL SYNDROMES A - Lower Back and Leg Pain 1- Lumbar Spine Stenosis * affects mainly late middle-aged and older adults. * The cause is multifactorial ,with disk disease , bony hypertrophy , and thickening of the ligamentum flavum being the most important. * Some of the symptoms are undoubtedly caused by direct pressure of these tissues on the cauda equina and exiting nerve roots, but a major contributor appears to be compression of the vascular supply of the nerve roots . * Standing is associated with extension of the lumbar spine, which causes anterior bulging of the ligamentum flavum that lies posteriorly. * Compression of the vascular supply creates nerve root ischemia , which can produce severe pain and weakness with exertion .

16. * Presents with leg pain that is exacerbated by standing and walking and relieved promptly by sitting . * Lying down , especially in the prone position , may exacerbate the low back pain , again through lumbar extension, a feature that helps differentiate lumbar spine stenosis from lumbar radiculopathy . * This neurogenic pain is called pseudoclaudication or neurogenic claudication * Patients suffering from spinal stenosis exhibit a simian posture ( with a forward-flexed trunk and slightly bent knees when walking, to decrease the symptoms) * Extension of the spine may cause an increase in symptoms . * Weakness and lack of coordination in the affected extremity may be noted.

17. * Patients often have a positive stoop test for spinal stenosis. * Decreased sensation, weakness, and reflex changes are demonstrated on physical examination . * Occasionally, patients suffering from spinal stenosis experience compression of the lumbar spinal nerve roots and cauda equina , with resulting lumbar myelopathy or cauda equina syndrome. * These patients experience varying degrees of lower extremity weakness and bowel and bladder symptoms (neurosurgical emergency) * Mimics of spinal stenosis include low back strain , lumbar bursitis , lumbar fibromyositis , inflammatory arthritis , and disorders of the lumbar spinal cord, roots, plexus, and nerves, including diabetic femoral neuropathy .

18. Figure 78-4 Acquired degenerative spinal stenosis. A and B, Sagittal T2- and T1-weighted magnetic resonance imaging (MRI) demonstrates severe disk degeneration at L3-4 and L4-5, with disk desiccation, disk space narrowing, irregularity of the adjacent vertebral end plates , and posterior bulging disks. The nerve roots of the cauda equina have an undulating or wavy appearance because of the marked constriction at L3-4. C and D, On axial T2-weighted MRI, the combination of posterior bulging disks , facet hypertrophy, and thickened ligamenta flava causes severe spinal canal stenosis at L3-4 and moderate stenosis at L4-5. Also note severe compromise of the lateral recesses at L3-4 bilaterally.

19. * EMG can also distinguish plexopathy from radiculopathy and can identify a coexistent entrapment neuropathy that may confuse the diagnosis. * MRI or CT of the lumbar spine shows obliteration of the subarachnoid space at the level of the lesion. * The hypertrophied ligamentum flavum and osteophyte formation usually are evident on these studies. * If doubt about the diagnosis exists, myelography with postmyelographic CT scanning can be performed. * Weakness of the legs or sphincter disturbance indicates a need for decompression . * If the diagnosis is in question, send for CBC , ESR , antinuclear antibody testing , human leukocyte antigen (HLA)-B27 antigen screening , and automated blood chemistry should be performed to rule out other causes of the patient's pain.

20. * Treatment: * Physical therapy , combined with nonsteroidal antiinflammatory drugs and skeletal muscle relaxants * If necessary, caudal or lumbar epidural nerve blocks can be added. * Caudal epidural blocks with local anesthetic and steroid are extremely effective in the treatment of spinal stenosis. * Underlying sleep disturbance and depression are best treated with a tricyclic antidepressant such as nortriptyline , which can be started at a single bedtime dose of 25 mg .

21. 2- Cauda Equina Syndrome and Conus Medullaris Syndrome * Lesions of the lumbar spine can result in damage to the conus medullaris , cauda equina , or both. Cauda equina syndrome * is compression of the nerve roots below the termination of the spinal cord . * Nerve root dysfunction is due to direct compression by surrounding structures. * Important causes include acute trauma , chronic degenerative bony disease with retropulsion of fragments into the spinal canal, lumbar disk disease , infections such as abscess, intraspinal and meningeal tumor , and intraspinal hematoma .

22. * This syndrome can be a rare complication of minor and major spinal procedures * Cauda equina syndrome usually develops as an insidious chronic process unless due to acute trauma. * Symptoms can include back pain , leg pain , and weakness and cramps in the legs . * Sensory symptoms can be sensory loss as well as neuropathic pain . * Sphincter disturbance is common , especially with progression .

23. Conus medullaris syndrome * is due to damage to the terminus of the spinal cord above most of the cauda equina and therefore at a higher spinal level. * Etiology can be compression from all the conditions listed above plus occasional infiltrating lesions of the conus medullaris itself, especially by tumor. * Conus medullaris syndrome is usually more rapidly progressive , associated with earlier back pain and sphincter disturbance , and is more likely to be associated with preservation of some lower extremity reflexes , usually patellar. *If MRI cannot be performed, many causes of both syndromes can be identified on CT of the spine but contrast may be required.

24. 3- Lumbosacral Radiculopathy ( sciatica) * Lumbar radiculopathy is a constellation of symptoms including neurogenic back and lower extremity pain emanating from the lumbar nerve roots. * Causes : herniated disk , foraminal stenosis , tumor , osteophyte formation , and, rarely, infection . * Herniated disk is more common in young patients ; osteophyte formation is more common in older patients . * Signs and Symptoms : * pain , numbness , tingling , and paresthesias in the distribution of the affected nerve root or roots * Patients may also note weakness and lack of coordination in the affected extremity. * Muscle spasms and back pain, as well as pain referred into the buttocks, are common.

25. * Decreased sensation, weakness, and reflex changes * They may experience a reflex shifting of the trunk to one side, called list * Lasègue's straight leg raising sign is almost always positive * Occasionally,patients suffering from lumbar radiculopathy experience compression of the lumbar spinal nerve roots and cauda equina that results in lumbar myelopathy or cauda equina syndrome ; if so, they experience varying degrees of lower extremity weakness and bowel and bladder symptoms .

26. Testing: 1- MRI , CT or MYelography 2- Diskography may also help clarify the diagnosis in difficult cases 3- Radionuclide bone scanning and plain radiography are indicated if fracture or a bony abnormality , such as metastatic disease, is being considered. 4- EMG and nerve conduction velocity testing provide neurophysiologic information about the actual status of each individual nerve root and the lumbar plexus . * EMG can also distinguish plexopathy from radiculopathy and can identify a coexistent entrapment neuropathy , such as tarsal tunnel syndrome , which may confuse the diagnosis.

27. * NCS findings usually are norma l in patients with lumbosacral radiculopathy, although F-waves may be delayed in the affected root. * EMG can reveal evidence of denervation in a nerve root distribution and usually can differentiate peripheral neuropathic processes from radiculopathy. * This study also can determine whether denervation is present with radiculopathy . 5- other lab tests as for lumbar spinal stenosis Management : as for lumbar spinal stenosis * Surgery indications: intractable pain refractory to conservative care; when weakness is prominent , especially if it is unresponsive to conservative management; and when sphincter disturbance is present . * Sphincter disturbance caused by lumbar disk disease or spondylosis necessitates consideration of urgent surgery.

28. 4- Arachnoiditis * is inflammation of the arachnoid membranes surrounding the spinal cord. * The inflammation can be caused by a number of processes including trauma to the spinal canal by injury or surgery, chronic compression of spinal nerves, chemicals such as intrathecal chemotherapy or contrast agents, blood products from subarachnoid hemorrhage, infections, or neoplasms. * There is chronic inflammation of the motor and sensory nerve roots. * The inflammation results in fibrinous adhesions between the membranes and nerve roots and between adjacent nerve roots.

29. * Common symptoms include pain in the back and legs which typically has a neuropathic character. * Sensory symptoms can be loss of sensation or dysesthesias . * Muscle symptoms can include twitching and cramps, and in severe cases, weakness or even paralysis can develop. * Diagnosis of arachnoiditis is suspected in patients with low back and leg pain who have radiological studies which suggest the diagnosis; * arachnoiditis is seldom a diagnosis of first consideration during initial evaluation. * MRI shows thickened and clumped nerve roots. * Careful examination of the imaging shows nerve roots adherent to each other and to the dura . * myelography can show the same overall appearance.

30. * EMG can identify denervation spanning single root distributions and document motor dysfunction, but no EMG findings are specific for arachnoiditis . * CSF analysis is performed if the differential diagnosis includes meningeal infection or tumor . * Treatment of arachnoiditis is usually symptomatic since the underlying cause is either remote or unknown . *Preventing this disorder is the best approach and can be achieved by avoiding injury and sometimes by administering steroids with intrathecal medications.

31. 5- Plexopathy One: Neoplastic Lumbosacral Plexopathy * Neoplasms affecting the lumbosacral plexus can be solid or infiltrating. * Both can produce severe neuropathic pain affecting one or both sides of the lumbosacral plexus. * Diagnosis is suspected when a patient with known cancer presents with pain and often weakness of one or both legs. * Diagnosis might be stumbled upon if there is no known cancer, with paravertebral tumor identified on lumbar spine MRI or other scan of the abdomen and pelvis. * The differential diagnosis might include radiation plexopathy , EMG can be helpful with that differentiation

32. * MRI is diagnostic * Treatment depends on the tumor type and stage: -- If there is no known cancer diagnosis then biopsy with or without excision is usually performed. -- Complete excision of some solid tumors is possible. -- Otherwise , radiation therapy is given initially. * Pain often is relieved shortly after the radiation therapy has begun. During initial treatment, anticonvulsants can be used to relieve the neuropathic pain. Pure analgesics also may be used and sustained-release opiate formulations are effective in treating this condition.

33. Two :Plexus Injury from Retroperitoneal Abscess * is caused by peritonitis from gastrointestinal neoplasms or following surgery. * Retroperitoneal abscess can affect the lumbosacral plexus. *Patients present with abdominal and flank pain, often with overt signs of systemic infection , with fever, malaise, elevated white blood cell counts, and elevated C-reactive protein (CRP) concentration. * The diagnosis is confirmed by CT of the abdomen. * Management typically begins with surgical drainage followed by prolonged antibiotic treatment. * Narcotics usually are needed for the pain of retroperitoneal abscess.

34. Three :Plexus Injury from Retroperitoneal Hematoma . *is caused by a bleeding disorder, a pelvic fracture, or abdominal surgery. * Occasionally , bleeding from the site of arteriography puncture can result in tracking of blood into the region of the lumbosacral plexus, especially after thrombolytic therapy or anticoagulation. * Hematoma has also been described in patients after lumbar plexus block and may be delayed * This diagnosis should be suspected in patients with leg motor and sensory symptoms who are at risk for intraabdominal hemorrhage; abdomen and leg pain are common. * Confirmation of the diagnosis is by CT of the abdomen, which can show blood in the region of the plexus. * Treatment of plexus hematoma is supportive. * Evacuation of the hematoma is seldom needed, and surgery commonly is reserved for patients with continued blood loss, which must be arrested.

35. B- Leg Pain without Lower Back Pain 1- Peripheral Nerve Syndromes * is commonly the result of sustained compression . * Peroneal palsy is the most common lower extremity syndrome, usually caused by pressure at the fibular neck . * Femoral neuropathy commonly results from intraabdominal causes and can be difficult to differentiate from upper lumbar plexopathy . * The diagnosis of peripheral nerve palsy is clinical, with symptoms and signs confined to one neural distribution. * Patients usually present with neuropathic pain and sensory loss. * Dysesthesias and paresthesias in the affected distribution are common. * Reflex abnormalities depend on the individual nerves affected.

36. * Definitive treatment of peripheral nerve entrapment is surgical release . * Tumor compression of peripheral nerves can be treated surgically, but radiation therapy can shrink the tumor, thereby relieving pain. One: Femoral Neuropathy : The femoral nerve usually is injured in the pelvis as it passes beneath the inguinal ligament or in the leg. * Intra-abdominal disorders including mass lesions and hematoma are commonly implicated. * Femoral artery puncture for angiography also may be a cause, either directly or via resultant hematoma. * Patients present with weakness that is most easily detected in the psoas, because the quadriceps are so strong. * Sensory loss is over the anterior thigh and medial aspect of the calf and has a saphenous nerve distribution (the terminal sensory branch of the femoral nerve).

37. * This distribution of sensory loss is helpful to differentiate femoral neuropathy from lumbar radiculopathy. * The patellar reflex usually is depressed . * The diagnosis can be supported by EMG evidence of denervation in the quadriceps but not in the lower leg or posterior thigh muscles. * The adductors are especially important to test because they are innervated by the same nerve roots that supply the femoral nerve but instead are innervated by the obturator nerve. * Normal EMG findings cannot rule out this diagnosis , because many patients do not have active or chronic denervation. * NCS of the femoral nerve is difficult, especially in large patients, who are predisposed to development of femoral neuropathy.

38. ** Treatment is seldom surgical, except for the removal of a massive psoas or iliacus hematoma or mass lesion. ** Weight loss and avoidance of marked hip flexion can reduce the chance of persistent damage. ** Physical therapy will aid recovery of motor power. Femoral neuropathy in the absence of marked damage usually resolves .

39. Two: Meralgia Paresthetica : Dysfunction of the lateral femoral cutaneous nerve commonly is caused by compression as it passes beneath the inguinal ligament . * Obesity and pregnancy predispose to this disorder, as does intra-abdominal surgery of a variety of types. * Meralgia paresthetica is the sensory syndrome of pain and sensory loss on the lateral thigh. * Patients present with numbness and often pain on the lateral thigh. * Motor deficits are not a feature. * Meralgia paresthetica is differentiated from femoral neuropathy by the lateral distribution of the sensory findings and the absence of motor and reflex abnormalities.

40. * Nerve conduction testing of the lateral femoral cutaneous nerve, although feasible, is technically difficult even in the best circumstances . It is even more difficult in obese patients, who are at particular risk for entrapment of the nerve. * Treatment is conservative. Weight loss usually is effective in preventing recurrence. * Medications and blocks for neuropathic pain are sometimes helpful.

41. Three: Sciatic Neuropathy : * The sciatic nerve is most likely to be injured as it leaves the sciatic notch and descends into the upper leg. * Compression can occur in patients in prolonged coma , especially those who are very thin. * The sciatic nerve also is susceptible to injury from pelvic and sacral fractures, hip surgery or dislocation, needle injection injuries, and any penetrating injury . * Patients present with pain that usually is localized close to the level of the sciatic nerve lesion, although substantial radiation of the pain may be a feature. * Loss of sensation is prominent below the knee, sparing the medial lower leg (the territory of the saphenous branch of the femoral nerve). *Weakness can affect all muscles of the lower leg, but peroneal -innervated muscles are more likely to demonstrate weakness for two reasons .

42. * First , tibial -innervated foot extensors are so strong that substantial weakness would have to be present for weakness to be evident on examination. * Second , the peroneal division of the sciatic nerve is more susceptible to compression injury than the tibial division, even high in the thigh. * Sciatic neuropathy is usually diagnosed clinically but can be supported by EMG evidence of denervation in sciatic innervated muscles; signs of denervation may not be seen until 4 weeks after injury. * Treatment of sciatic compression is supportive, with avoidance of recurrent compression. Medications for neuropathic pain are often used. Surgical exploration and decompression are performed only in patients with clear evidence of a structural lesion.

43. Four: Piriformis Syndrome: * is an uncommon * the sciatic nerve is compressed by the piriformis muscle in the posterior gluteal area (sciatic notch) * The piriformis muscle's primary function is to rotate the femur externally at the hip joint; this muscle is innervated by the sacral plexus . * With internal rotation of the femur, the tendinous insertion and belly of the muscle can compress the sciatic nerve ; if this compression persists, it can cause entrapment of the nerve. * * Hypertrophy of the piriformis muscle and other anatomical variants predispose affected persons to development of the syndrome.

44. The pain of piriformis syndrome can be exacerbated by lifting.

45. * This condition may affect not only the main sciatic trunk but also the superior gluteal nerve. * Patients present with pain in the buttock that radiates down the leg and foot and is exacerbated by adduction and flexion of the hip . * Pain tends to be aggravated by prolonged sitting, climbing steps, and other maneuvers that irritate the piriformis muscle . * Patients suffering from piriformis syndrome may develop an altered gait, leading to coexistent sacroiliac , back, and hip pain that confuses the clinical picture. * Physical findings include tenderness over the sciatic notch. Palpation of the piriformis muscle reveals tenderness and a swollen, indurated muscle belly . * A positive Tinel sign over the sciatic nerve as it passes beneath the piriformis muscle is often present.

46. * A positive straight leg raising test result suggests sciatic nerve entrapment. * Lifting or bending at the waist and hips increases the pain in most patients suffering from piriformis syndrome * Weakness of the affected gluteal muscles and lower extremity and, ultimately, muscle wasting are seen in patients with advanced, untreated cases of piriformis syndrome . * ( EMG) can distinguish lumbar radiculopathy from piriformis syndrome. * Plain radiographs of the back, hip , and pelvis are indicated in all patients who present with piriformis syndrome, to rule out occult bony disorders . * additional testing including a complete blood count, uric acid level, erythrocyte sedimentation rate , and antinuclear antibody testing.

47. * It is a clinical diagnosis. * A patient with symptoms of sciatic neuropathy has no signs of radiculopathy or spinal stenosis on imaging. * MRI neurography may show the lesion in many patients ## Differential Diagnosis * Lumbar radiculopathy * primary hip disease ; radiographs of the hip and EMG can make the distinction . - In addition, most patients with lumbar radiculopathy have back pain associated with reflex, motor , and sensory changes, whereas patients with piriformis syndrome have only secondary back pain and no reflex changes . ## Lumbar radiculopathy and sciatic nerve entrapment may coexist as the double-crush syndrome .

48. * it is managed with anti-inflammatory agents and sometimes local injections of steroids . * The local application of heat and cold may also be beneficial. * If the patient sleeps on his or her side, placing a pillow between the legs may be helpful. * If the patient is suffering from significant paresthesias , gabapentin may be added. * For patients who do not respond to these treatment modalities, injection of local anesthetic and methylprednisolone in the region of the sciatic nerve at the level of the piriformis muscle is a reasonable next step . * Surgical treatment is rarely performed

49. Five: Peroneal (Fibular) Neuropathy * Peroneal neuropathy commonly is caused by compression of the nerve as it passes from the popliteal fossa across the fibular neck into the anterior compartment of the lower leg. * Patients often present with foot drop from weakness of the tibialis anterior muscle. * The diagnosis is confirmed by NCS and EMG, with slowing of peroneal nerve conduction across the region of entrapment, usually across the fibular neck . * The EMG shows evidence of active and chronic denervation in many patients, in keeping with the axonal damage indicated by the foot drop * Peroneal neuropathy can develop in a variety of conditions which predispose to mechanical compression such as prolonged bed rest, hyperflexion of the knee, sitting with crossed legs , and lower leg cast. * Peroneal neuropathy is of increased incidence in patients with peripheral neuropathy, those with a neurofibrous band attached to the peroneus longus , and ballet dancers

50. Six: Polyneuropathy: * Peripheral neuropathy is a common cause of lower-extremity pain. * Among the most important causes are diabetes mellitus , familial neuropathy , metabolic neuropathies, and vasculitis . * Pain is the presenting manifestation and differs in character according to the type of neuropathy. * Small-fiber neuropathies manifest with burning pain that often is worse in the evening. * Large-fiber neuropathies manifest with dysesthesias and paresthesias , often with electric shock-like pains . * Diagnosis usually is confirmed by NCS and EMG. * Axonal neuropathy is more common than demyelinating neuropathy. * Occasionally , patients with a predominantly small-fiber sensory neuropathy have normal NCS findings.

51. * Treatment is with tricyclic antidepressants or anticonvulsants. Amitriptyline commonly is used for patients with smallfiber neuropathic pain. * Anticonvulsants are used predominantly for patients with large-fiber neuropathic pain. * When patients have symptoms of both, treatment with gabapentin, pregabalin , or oxcarbazepine can be helpful. * Combination therapy with a tricyclic and anticonvulsant may be beneficial. * Pure analgesics occasionally are used on a nightly basis to assist with sleep

52. 3- Plexopathy One: Lumbosacral Plexitis * It is similar to brachial plexitis , a presumed autoimmune process, but is less common . * This entity is differentiated from radiculitis , which can be an inflammatory disorder of autoimmune or infectious origin * Management of idiopathic lumbosacral plexitis is supportive, with no medical intervention known to alter the course of the disease. * Anticonvulsants commonly are used for pain management. * Corticosteroids and high-dose intravenous immunoglobulin also are used occasionally, although it is not clear that their benefits outweigh the risks. * The relatively short duration of the pain makes opiates appropriate for some patients if needed.

53. Two: Diabetic Amyotrophy : * Diabetic amyotrophy is lumbosacral plexopathy occurring in persons with diabetes mellitus. * The disorder is thought to be an inflammatory vasculopathy , with damage that probably is immune mediated. * Patients present with pain in the hip and thigh associated with weakness of the quadriceps, psoas, and adductors. * The plexopathy is more often unilateral than bilateral. * Diagnosis is suspected by proximal pain and weakness of a leg in a patient with known diabetes. * This disorder must be differentiated from lumbar radiculopathy and other structural lesions in the region of the plexus. * NCSs and EMG show coexistent peripheral polyneuropathy plus denervation in proximal muscles including quadriceps, psoas, and adductors. * MRI and CT do not show a structural lesion. * Treatment is symptomatic. Immune-modulating treatments have been tried but are not standard. Most patients improve , although recovery is usually incomplete. The pain abates before recovery of muscle strength.

54. 4- Herpes Zoster * pain in a single nerve root distribution. * In most patients, a vesicular rash develops in the same cutaneous distribution usually several days after the onset of the pain. * When the rash crusts over, there is commonly pigmentary changes of variable duration. * The pain abates as the inflammation recedes, although the patient may be left with sensory or motor deficit. * Weakness can be evident in muscles innervated predominantly by the single nerve root. * Diagnosis is clinical, and with a typical presentation including rash, structural imaging usually is not necessary.

55. * EMG and imaging are usually considered if the diagnosis is uncertain or with prolonged deficit. *The differential diagnosis is broader in scope before development of the rash. * Treatment with antiviral agents such as acyclovir or famciclovir should begin within 72 hours of symptom onset. * Early treatment may help hasten recovery and reduce the incidence of postherpetic neuralgia. * Corticosteroids are often used in immuno -competent patients and especially for zoster ophthalmicus .

56. 5-Claudication of Leg Arteries * Arterial claudication is an important element in the differential diagnosis of spinal stenosis. * Vascular disease of the iliac arteries and terminal branches results in marginal perfusion of lower limb muscles. * Walking and other moderate activities exacerbate the ischemia, producing pain and weakness with exertion. * The clinical picture may resemble that of spinal stenosis, but differentiating features include the lack of back pain , lack of exacerbation of leg pain with recumbent lumbar extension , and vascular changes in the leg. * Claudication is diagnosed by vascular imaging. *Ultrasound examination can be a good screening test but angiography can provide a definitive diagnosis and in some patients can be the means for definitive treatment by angioplasty.

57. C- Lower Back Pain without Leg Pain 1- Mechanical Lower Back Pain * Mechanical lower back pain usually is caused by strain of paraspinal muscles and ligaments with local inflammation. * Muscle tears also may cause acute lower back pain. Therefore, mechanical lower back pain usually is a combination of bone, muscular , and connective tissue pain. * Patients present with pain in the lower back without radicular symptoms and show no motor, sensory, or reflex abnormalities on examination. * Any weakness or gait disturbance is due to pain and not neurological deficit .

58. * Diagnosis is based on the clinical features and exclusion of other causes. * In the absence of objective neurological deficits, imaging including spinal MRI usually is not needed initially. * In the absence of signs of bony or neural destruction, conservative management may begin . * If the patient does not respond to initial treatment, MRI may be indicated. * Mechanical lower back pain usually is treated by an initial period of rest of approximately 2 days, followed by an increase in activity including physical therapy. * Muscle relaxants and anti-inflammatories are often used. * Surgery and repetitive nerve blocks are seldom indicated for mechanical back pain.

59. 2- Sacroiliac Joint Inflammation ( Sacroilitis ) * presents with pain isolated to the back and just lateral to the spine in the region of the SI joint. * This is often a component of more generalized arthritic conditions including ankylosing spondylitis but can also be seen in psoriatic and autoimmune arthritides * Diagnosis is suspected with the local pain without radiation. MRI can show the inflammatory change * While a primary inflammatory or degenerative lesion is most common, in some cases infections and destructive processes can produce similar symptoms

60. 3- Facet Joint Pain Syndrome * Pain from the facet joints of the lumbosacral spine usually is not an isolated entity but rather a component of mechanical. back pain. * Pain results from long-term degenerative changes in the facet joints, usually caused by strain. Repetitive strenuous activity , excessive weight, and abnormal posture may predispose affected persons to the development of facet pain. * Acute trauma to the back may produce active joint inflammation that can be self-limited. * Diagnosis is suspected with pain usually lateral to the spine which is exacerbated by spine extension or bending toward the affected side. * Facet pain often is bilateral. Pain can be exacerbated by prolonged sitting or walking up steps, as well as retaining one position for a prolonged time.

61. * Patients present with pain without motor, sensory, or reflex deficit unless radiculopathy or spinal stenosis is also present. * Imaging may show chronic degenerative changes or be normal. * Facet pain usually is treated with anti-inflammatory agents, physical therapy, and avoidance of precipitating activities. *Facet blocks are usually not necessary, and effectiveness in terms of long-term relief is controversial

62. 4- Lumbar Spine Osteomyelitis * Vertebral osteomyelitis is infection of the vertebrae, usually due to Staphylococcus aureus . * This is most common in the lumbar region and may develop as a sequela of trauma or systemic infection. * Adjacent structures are often affected with diskitis often resulting from this, although the route of infection can be from infected disk to vertebra . * Diagnosis is suspected by lower back pain associated with systemic signs of infection—fever, elevated CRP, ESR, WBC * Helpful clinical features include pain with percussion over the spine, marked limitation of motion of the spine, and tightness of paraspinal muscles which is more marked than usually seen with mechanical pain.

63. * MRI shows changes in the vertebral body and often in disk and adjacent psoas muscle. * Radiographs show degeneration of the disk margin of the vertebral body and disk space narrowing. * Needle biopsy can reveal the causative organism in most cases. * The diagnosis can easily be missed initially, since it can occur in patients with pre-existing lumbar spine pain, and inflammatory signs may not be marked early on * Treatment is with antibiotics and bed rest. Surgical debridement is needed in patients who do not respond to antibiotics.

64. 5- Lumbar Spine Compression * Compression of the lumbar vertebral bodies occurs in the setting of acute trauma, osteoporosis, infection, or tumor. * Compression with minimal trauma is especially of concern for advanced osteoporosis or tumor. * Patients present with severe lower back pain, usually without radicular symptoms. * If the collapse results in impingement on nerve roots, radicular pain may develop. * Compression of the cauda equina can result in weakness of the legs and sphincter disturbance . * The diagnosis of lumbar spine compression is suggested by a clinical presentation of lower back pain that is exacerbated by movement, jarring, or certain postures such as bending or twisting. * Imaging of almost any type shows the bone deformation or destruction.

65. * MRI or bone scan may be needed to help differentiate tumor or infection from degenerative causes. * Treatment consists of immobilization of the fracture site, which may include bracing. Pure analgesics often are needed, especially at night. * Corticosteroids should be avoided if the cause is osteoporotic but can be very helpful for malignant vertebral collapse. * Vertebroplasty can be very helpful. * Surgery may be needed for unstable lesions or if there is spinal or neural compression. * Radiation therapy is used for malignant collapse

66. 6- Lumbar Diskitis * Diskitis is an inflammatory process affecting the intervertebral disks of any level, often occurring in the lumbar spine. * The organism is dependent on the infectious source, with Staphylococcus aureus and mycobacteria being among the most important causes. * Diskitis associated with recent lumbar surgery is likely to be caused by resistant bacteria. * In children, extraspinal manifestations of infection are less likely * Patients present with lower back pain with marked restriction of flexion of the spine. * Patients with postoperative diskitis usually have systemic inflammatory markers, but overt signs of infection with fever and chills may be absent.

67. * A diagnosis of lumbar diskitis is suggested by the presence of severe lower back pain without a radicular component, often with tenderness and spasm of the paravertebral muscles associated with willingness of the patient to flex the hips but not the spine * ESR and CRP concentration are usually increased. * The diagnosis can be confirmed by MRI , and often shows changes in the end-plates of the adjacent vertebrae . * Bone scan shows increased uptake in the region of the infected disk. * Biopsy often is needed to identify an organism . * Treatment begins with bed rest and antibiotics * Extensive surgery usually is not necessary; even tuberculous diskitis is successfully treated with antibiotics in more than 80% of cases * In some patients, diskectomy with fusion of the adjacent vertebral bodies may be required for relief of symptoms.

68. 7- Spinal epidural abscess * Bacterial infection of the epidural space can develop into a spinal epidural abscess. * The infectious organisms can spread from adjacent structures, the skin, or hematogenously . * There is a triad of fever, back pain, and neurologic deficits; however, the combination of all three is rarely seen. * Most patients have limited symptomatology initially. * Diagnosis is confirmed by MRI but contrast may be needed to reveal the infection. * We have even seen cases where the lesion was not initially seen, but subsequently visualized on repeat scanning. * Laboratory studies including elevated peripheral blood WBC, CRP, and ESR are frequently abnormal. * Treatment usually begins with identification of the organism from blood or surgery * An increasing proportion of patients is diagnosed by MRI when the epidural abscess is quite small. In this case, aspiration rather than open surgery or even empiric treatment may be appropriate.

69. PITFALLS Low Back Pain: Disc, Tumor, Diskitis , or Epidural Abscess * If the patient initially has signs of neurologic deficit or clinical/laboratory signs of inflammation then evaluation without delay is appropriate . * Contrast-enhanced MRI is more sensitive for looking for acute inflammatory or neoplastic changes . * CSF analysis may be needed to look for neoplastic meningitis which can present with polyradiculopathy , associated with leg as well as back pain. * Peripheral blood markers of inflammatory disease, such as ESR, CRP, and peripheral blood WBC, are often but not invariably elevated in patients with epidural abscess and spinal osteomyelitis.

70. Lower Back Pain from Intra-abdominal and Pelvic Causes * Patients with intra-abdominal and pelvic lesions can present to the neurologist with symptoms of isolated back pain or even pain which may resemble radiculopathy. * Neuropathic pain in this case developed from plexus invasion. * Abdominal and pelvic disorders which may present with back pain and/or leg pain are numerous, but include not only gynecological lesions but also renal, hepatic, pancreatic, and other gastrointestinal lesions.

71. Lower Back and Leg Pain from Arterial Insufficiency * Patients presenting to the neurologist with lower back and leg pain may be considered for lumbar spine lesion, but a peripheral arterial process also should be considered. * Rarely , patients are seen who present with saddle emboli to the femoral arteries where the clinical presentation can resemble cauda equina syndrome * If cauda equina syndrome is suspected , rapid evaluation is performed and if this does not show a clear reasonable etiology then peripheral arterial disease as well as other visceral conditions should be considered. * On initial exam, clinical signs of ischemia should be considered for further study even before spine imaging. * While peripheral ischemia usually produces leg pain without back pain , back pain can occasionally be manifest and even be unrelated to the acute leg pain.