Background: The article presents results of systematic review focusing on clinical effectiveness and safety of interferon β-1b use in patients with multiple sclerosis and its direct comparison with interferon β-1a. Material and methods: The assessment is based on meta-analysis of the results of clinical trials identified in the systematic review that followed Cochrane Collaboration methodology. Primary endpoints related to therapy effectiveness and some secondary endpoints which may indirectly reflect intervention efficacy have been analyzed. Major electronic databases (incl. EMBASE, MEDLINE, CENTRAL) have been searched. Results: Interferon β-1b administered subcutaneously in a dose of 8 MIU each other day (e.o.d.) was found to have confirmed effectiveness with regard to analyzed primary endpoints and also an acceptable safety profile in relapsing-remitting multiple sclerosis during a period of 2-5 years and in secondary progressive multiple sclerosis during a period of 3 years. The potency of intervention is regarded as clinically significant. Effectiveness of interferon β-1b in primary multiple sclerosis has not been confirmed. On the basis of the results of a single clinical trial (INCOMIN) it is concluded that interferon β-1b administered subcutaneously in the dose of 8 MIU e.o.d. might have higher efficacy compared to 6 MIU once weekly intramuscular interferon β-1a in relapsing-remitting multiple sclerosis during a period of 2 years. Conclusions: The results show that interferon β-1b is a medication with confirmed effectiveness in multiple sclerosis with relapsing activity and could be more effective than interferon β-1a given once a week.
Peripheral nerve entrapment is a condition of chronic injury of a nerve passing through a narrow, noncompliant anatomical canal. This leads to clinically apparent entrapment neuropathy with pain and paresthesias in distribution of the affected nerve, progressing to motor weakness and muscle atrophy. The most common peripheral nerve entrapment is carpal tunnel syndrome found in 0.5 to 3% of the population. In the US, patients with entrapment neuropathies make up 10 to 20% of all neurosurgical cases. Deformities resulting from bone fractures or arthritis may account for chronic nerve compression as found in the classic tardy ulnar palsy. Not unusually, nerves are compressed by atypical anatomical structures such as Struthers ligament (median nerve), arcades of Struthers (ulnar nerve) or arcade of Fröhse (radial nerve). Superficially located nerves are vulnerable to direct trauma during the routine daily activities as this is the case with the ulnar nerve at the elbow and with the superficial lateral femoral nerve in patients wearing tight jeans. Entrapment neuropathies are frequently associated with pregnancy and acromegaly, with metabolic disorders (diabetes mellitus, alcoholism, chronic hemodialyses) and with hereditary neuropathy with liability to pressure palsies (HNPP), the condition showing autosomal dominant inheritance and caused by the deletion of a segment of chromosome 17p11.2-12 which contains peripheral myelin protein-22 gene (PMP22). Following general considerations, the clinical symptoms and etiology of carpal tunnel syndrome, pronator teres syndrome, anterior interosseous nerve syndrome, entrapment of the ulnar nerve at the elbow and at the wrist and hand, posterior interosseous nerve syndrome, Wartenberg syndrome, thoracic outlet syndrome, entrapment of the suprascapular and musculocutaneous nerves, Roth syndrome, tarsal and anterior tarsal tunnel syndromes, neuropathies of peroneal nerves and saphenous nerve as well as Morton’s neuroma were reviewed in detail.
The paper reviews the pathophysiology of both acute and chronic peripheral nerve entrapments. Factors influencing susceptibility of the nerve fibers to such an injury were presented. Pathophysiological mechanisms influencing extent of the injury of the nerve were looked at, taking into consideration cases of double crush syndrome. Moreover, pathological changes occuring in the instances of short-lasting acute compression of the nerve were described, namely metabolic conduction block and segmental, local perinodal demyelinisation with partial or complete conduction block. Furthermore, microscopic and ultrastructural changes found in chronically compressed nerves were presented in detail, explaining the mechanisms of demyelinisation injury in the early phase of entrapment neuropathy and demyelinisation-axonal injury in the advanced stage of the disease. This paper reviews two best known grading systems of peripheral nerve injuries i.e. Seddon’s and Sunderland’s classifications which assess the functional condition of the nerve and ongoing histological changes. These classifications were explained along with neurophysiological data in order to facilitate understanding of neurography and EMG tests results as the guide for therapy and prognosis.
The paper describes in detail electrophysiological studies (i.e. neurography and EMG) necessary to establish diagnosis in entrapment mononeuropathies. Neurophysiological criteria of diagnosing segmental demyelinization in entrapment neuropathies as well as axonal injury, denervation and reinnervation, allowing assessment of the degree of damage and therefore useful in choosing appropriate management were presented. Furthermore, concise anatomical knowledge on the peripheral nerves of the upper and lower limbs was reviewed pointing out distribution of motor and sensory innervation and the most frequently encountered nerve anomalies. Moreover, this paper gives a list of electroneurophysiological tests (taking into consideration the comparative techniques applied in certain cases) mandatory in establishing diagnosis in each of entrapment neuropathies of the upper and lower limb as well as in the thoracic outlet syndrome. Consequently, a detailed account of interpretation of both neurography and EMG results was given along with necessary criteria for diagnosis of each of the entrapment neuropathies. Differential diagnosis was carefully considered both in terms of localizing the compression and ruling out other entities such as radiculopathy or plexopathy.
The diagnosis of nerve entrapment at osteofibrous tunnels relies primarily on clinical and electrodiagnostic findings. However, while electrodiagnostic studies are sensitive, they lack specificity and do not display the anatomic detail needed for precise localization and treatment planning. The radiological study of peripheral nerve disorders initially was limited to secondary skeletal changes on plain radiographs and CT. Plain radiographs are useful for evaluating bones for trauma and fractures, severe osteoarthritis, and other arthropathies. Routine CT is useful for its ability to display and evaluate the cross-sectional volume of the tunnel and for detecting subtle calcification in the tendons within the canal. CT also provides an excellent tool for evaluating bones through multiplanar and 3-dimensional reconstructions. MR imaging have been useful to exclude mass lesions in the vicinity of a peripheral nerve. Recent technical improvements in MRI have resulted in improved visualization of both normal and abnormal peripheral nerves. The refinement of high frequency broadband transducers with a range of 5-15 MHz, sophisticated focusing in the near field, and sensitive color and power Doppler technology have improved the ability to evaluate peripheral nerve entrapment in osteofibrous tunnels with ultrasonography (US).
This paper reviews current knowledge on management of entrapment neuropathies. An attempt of conservative therapy is appropriate in patients showing no motor deficit, particularly if entrapment neuropathy is associated with an endocrine disorder, potentially avoidable physical activity or with external compression of the nerve. Even though the natural history of entrapment neuropathies is poorly understood, it is well known that their course is not necessarily progressive and spontaneous remissions are not exceptional. This advocates conservative treatment in patients with mild symptoms in early stages of the disease. Such a treatment must ensure getting rid of the factors responsible for development of the neuropathy and usually includes temporary immobilization of the affected limb. Currently available data do not support the value of local steroid injections. Management problems encountered in patients with diabetes mellitus and in the cases of double or multiple crush syndrome were also discussed. Basing on the most recently published clinical data the author reviews indications to surgical treatment in each of the entrapment neuropathies. Operative techniques and strategies were presented and briefly assessed. Attention was drawn to the possible advantages and disadvantages of endoscopic surgery for carpal tunnel syndrome as compared with the open surgery. The results of operative treatment were looked at pointing out typical side effects and complications.