الفهرس 
Review of the motor systemOnly 14 pages are availabe for public view
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Abstract
Summary
Foot DROP is usually caused by LMN pathology, commonly due to disruption of conduction from the deep peroneal nerve (L4-L5). L4-L5 radiculopathy is the most common recognized cause of foot drop, usually caused by herniated nucleus pulposus or foraminal stenosis. Peripheral peroneal neuropathy is the next most common and is brought on by neurogenic and non-neurogenic causes such as nerve entrapment, diabetes mellitus, inflammatory neuropathy, trauma, masses or pressure near the fibular head, intraneural tumors, and vascular pathology. Central or UMN causes are extremely rare but must be considered. Therefore the first step in clinical evaluation of foot DROP is to exclude cord or other CNS pathology and to examine for other peripheral nervous system involvement.
A herniated lumbar disc is a condition in which there is protrusion of the intervertebral disc. Herniations occur most commonly through a posterolateral defect, but midline herniations may occur. Resulting compression of the spinal nerve root causes inflammation and pain, often along the anatomic course of the nerve. In the lumbar spine, this most often occurs at the L4-L5 and L5-S1 disc levels, causing involvement of the corresponding L5 and S1 nerve roots. As a result of both mechanical and biochemical changes around the nerve root, the patient will experience pain, paresthesia, and possibly weakness in one or both lower extremities (Foot Drop).
The term ”foot drop” refers to paralysis or weakness of the ankle dorsiflexors. The Degenerative lumbar spinal disorders (disc herniation or spinal stenosis) are known causes of nerve root dysfunction resulting in ankle dorsiflexor muscle weakness (tibialis anterior, extensor digitorum, peroneus tertius, extensor hallucis longus) which are innervated by the L4 and L5 roots.
With DROP foot, these muscles are inhibited from performing several functions during a normal walking stride, including swinging the toes up from the ground at the start of a stride and controlling the foot after the heel is planted near the end of a stride. Consequently, the most recognized foot DROP symptom occurs: high steppage gait.
The purpose of this study was to determine recovery rates of foot DROP after microdiscectomy and to evaluate possible factors that may affect recovery.
Few studies have described the incidence of foot DROP and its recovery after conventional surgery or microsurgery for herniated lumbar disc. Even fewer investigations, carried out on patients who had conventional surgery, there have been contradictory results concerning the proportion of patients who recover and the degree of recovery. Little and conflicting information is available on the factors which may affect the postoperative restoration of muscle strength (foot drop).therefore the studies had attempted to evaluate the results of microsurgical discectomy in patients with a herniated disc in the lumbar spine in order to determine the rate and degree of recovery after surgery, to investigate possible factors which may affect the recovery, and to analyse whether the persistent muscle deficit (foot drop) is associated with any subjective risk factors.
These studies indicates that in patients with herniated lumbar disc, which causes mild or severe weakness of muscles (foot drop) supplied by the L4 -- L5 nerve roots, a complete or almost complete recovery of strength will occur after microdiscectomy. The chance of complete recovery is better the less severe the neural deficit is and the less delayed (beyond two months) the operation. Even if the recovery is incomplete, the patient’s subjective functional capacity is not significantly impaired. By contrast, in patients with a severe deficit of L4 or L5 roots, surgery may lead to recovery of muscle strength, or alternatively, to no recovery and marked functional disability. In these patients with no recovery at all, no factor emerges as predictive of whether a good or a poor recovery of neurological function will follow surgery except for Diabetes.
In conclusion the recovery of foot DROP due to prolapsed lumbar disc after lumbar discectomy is generally favorable, with significant improvement occurring regardless of age, gender, history of smoking, duration of weakness or weakness grade. Prognostic factors related to worse outcome were history of diabetes. Foot DROP recovery was superior in the group of patients presenting with acute foot DROP and operated upon within 24-48 hours of weakness onset, as opposed to foot DROP recovery in the group of patients with a chronic progressive weakness.