tailieunhanh - Chapter 016. Back and Neck Pain (Part 5)

Laboratory, Imaging, and EMG Studies Routine laboratory studies are rarely needed for the initial evaluation of nonspecific acute ( | Chapter 016. Back and Neck Pain Part 5 Laboratory Imaging and EMG Studies Routine laboratory studies are rarely needed for the initial evaluation of nonspecific acute 3 months duration low back pain ALBP . If risk factors for a serious underlying cause are present then laboratory studies complete blood count CBC erythrocyte sedimentation rate ESR urinalysis are indicated. CT scanning is superior to routine x-rays for the detection of fractures involving posterior spine structures craniocervical and craniothoracic junctions C1 and C2 vertebrae bone fragments within the spinal canal or malalignment CT scans are increasingly used as a primary screening modality for moderate to severe trauma. In the absence of risk factors these imaging studies are rarely helpful in nonspecific ALBP. MRI and CT-myelography are the radiologic tests of choice for evaluation of most serious diseases involving the spine. MRI is superior for the definition of soft tissue structures whereas CT-myelography provides optimal imaging of the lateral recess of the spinal canal and bony lesions and is tolerated by claustrophobic patients. While the added diagnostic value of modern neuroimaging is significant there is concern that these studies may be overutilized in patients with ALBP. Electrodiagnostic studies can be used to assess the functional integrity of the peripheral nervous system Chap. e30 . Sensory nerve conduction studies are normal when focal sensory loss is due to nerve root damage because the nerve roots are proximal to the nerve cell bodies in the dorsal root ganglia. The diagnostic yield of needle EMG is higher than that of nerve conduction studies for radiculopathy. Denervation changes in a myotomal segmental distribution are detected by sampling multiple muscles supplied by different nerve roots and nerves the pattern of muscle involvement indicates the nerve root s responsible for the injury. Needle EMG provides objective information about motor nerve fiber injury when the .