Lateral Popliteal Nerve Research Articles

Bullous erythema nodosum leprosum: a case report from Nepal

A patient with lepromatous leprosy, while on WHO multidrug therapy (MDT) for multibacillary disease, was diagnosed as having dapsone syndrome with recurrent episodes of bullous lesions on the lower extremities for 4-5 years. The lesions were associated with high-grade fever. Examination revealed multiple hypopigmented macules on the limbs. Multiple atrophic scars were also found on the buttocks and lower limbs. Bilateral ulnar, radial cutaneous and lateral popliteal nerves were thickened. On day 10 of WHO-MB-MDT he developed a flaccid bulla on the lower leg. Skin slit smear showed a bacterial index (BI) of 3+ and the histopathology was consistent with type II reaction. High dose corticosteroid therapy was started but he continued to have new lesions, and was therefore referred to a centre where thalidomide was available. Clinical response was good and he remained symptom-free after gradual reduction in dosage. ENL should be differentiated from bullous drug reactions, pemphigus vulgaris, bullous pemphigoid and other blistering diseases.

Lateral approach to the sciatic nerve in the popliteal fossa: a comparison between 1.5% mepivacaine and 0.75% ropivacaine

Background and Objectives: Ropivacaine and mepivacaine are commonly used local anesthetics for peripheral nerve blockade. The purpose of the present study was to compare onset time, quality of anesthesia, and duration of analgesia with ropivacaine 0.75% and mepivacaine 1.5% for lateral popliteal nerve block. Methods: Fifty American Society of Anesthesiologists (ASA) physical status I or II patients scheduled for foot and ankle surgery with calf tourniquet under lateral popliteal sciatic nerve block were randomly assigned to receive 30 mL of either ropivacaine 0.75% or mepivacaine 1.5%. Time required for onset of sensory and motor block, resolution of motor blockade, onset of postsurgical pain, and time of first analgesic medication were recorded. Results: The 2 groups were similar with regard to demographic variables and duration of surgery. Onset of sensory and motor block was significantly shorter in the mepivacaine group (9.9 ± 3.3 min and 14.7 ± 3.6 min, respectively) than in the ropivacaine group (18.1 ± 6.1 min and 23.6 ± 5.5 min, respectively) ( P < 0.001). Resolution of motor block occurred later in the ropivacaine group than in the mepivacaine group ( P < 0.001), and duration of postoperative analgesia was significantly longer in the ropivacaine group (19 ± 3.4 h) compared with the mepivacaine group (5.9 ± 1.1 h) ( P < 0.001). Analgesic requirements were higher in mepivacaine group than in the ropivacaine group ( P < 0.001). There were 2 failed blocks, one in each group. Conclusions: Both ropivacaine and mepivacaine provided effective sciatic nerve blockade. Mepivacaine 1.5% displayed a significantly shorter onset time than ropivacaine 0.75%. Postoperatively, ropivacaine 0.75% resulted in longer-lasting analgesia and less need for oral pain medication.

Lateral approach to the sciatic nerve block in the popliteal fossa: correlation between evoked motor response and sensory block

Background and objectives: The purpose of this study was to identify which of two motor responses of the foot (plantar flexion versus dorsiflexion) best predicts complete sensory blockade of the sciatic nerve when is used for lateral popliteal sciatic nerve block. Methods: Thirty American Society of Anesthesiologist physical status I or II patients scheduled for foot and ankle surgery under lateral popliteal sciatic nerve block were enrolled in the study. During each block, the needle was placed to evoke one of the following motor responses of the foot: plantar flexion or dorsiflexion. Thirty milliliters of 0.75% ropivacaine was injected after the motor response was elicited at <0.5 mA. The sequence of elicited motor response was randomized. Sensory blockade of the areas of the foot innervated by the deep peroneal, superficial peroneal, posterior tibial, and sural nerves was checked in a blinded manner. Time required for onset of sensory and motor block of the foot was recorded. Results: The 2 groups were similar with regard to demographic variables and type of surgery. The total of nerves blocked (deep and superficial peroneal, posterior tibial, and sural nerves) after elicited plantar flexion was greater (complete sensory block in 58 of 60 nerve distributions) than after elicited dorsiflexion (34 of 60 nerve distributions) ( P < .05). Onset of complete sensory and motor blockade of the foot was faster after elicited plantar flexion (16.6 ± 5.1 minutes, 20.1 ± 5.1 minutes, respectively) than after elicited dorsiflexion (24.3 ± 5.1 minutes, 28.1 ± 5.0 min, P < .05). Conclusions: After stimulation of the sciatic nerve, plantar flexion better predicts complete sensory blockade of the foot than dorsiflexion when using the lateral approach to the popliteal fossa. The findings of the present study apply to a single injection of 30 mL of ropivacaine 0.75%.

Origin and make up of the human sural nerve.

The dissection of 37 cadavers has shown that in only a third of cases, the sural nerve comes from the communication between the medial cutaneous nerve, derived from the tibial nerve, and the communicating branch of the lateral cutaneous nerve of the leg which comes from the lateral popliteal nerve. The communication is most often at the junction between the proximal two-thirds and distal third of the leg, on average 2 mm below the transverse crease of the popliteal fossa. The medial cutaneous nerve was absent in only one case. On the other hand, in 11 cases the lateral cutaneous nerve or its communicating branch was missing. In 12 cases without any anastomoses, the route of the sural nerve was followed by the medial cutaneous nerve of the leg in 9 cases and by the lateral cutaneous nerve in 3 cases. The majority of branches to the proximal half of the calf came from the lateral cutaneous nerve. In the lower part of the leg, the sural nerve and/or the medial cutaneous nerve gave numerous branches to the Achilles' tendon and to the integuments of the lateral aspect of the heel and lateral malleolus.

Safe meniscal suturing: observations from a cadaver study

Our aim in this article was to determine which combinations of portals and cannulae were safe to use for suturing menisci with an `inside out' technique. A series of sutures were placed arthroscopically into the menisci of 12 cadaver knees using different combinations of portals, cannulae and positions of the knee. All popliteal fossae were then dissected. The lateral popliteal nerve was never endangered providing that the needles exited anterior to the biceps tendon. Medially the saphenous vein and nerve need to be protected as they were always at risk by whatever route was used. The popliteal vessels and tibial nerve were never endangered provided the needles were directed away from the mid-line of the limb. Both menisci should be sutured with the knee flexed and with the capsule exposed. A suture catcher is recommended. It is concluded that `inside out' meniscal suturing is a safe technique provided that the above anatomical constraints are recognised.

A painful subcutaneous neurilemmoma attached to a peripheral nerve

Neurilemmomas are relatively uncommon encapsulated tumors derived from Schwann cells of peripheral and cranial nerves. In the skin, they can occur intradermally or subcutaneously. Although the dermal lesions are typically small asymptomatic nodules or papules that can be simply removed without significant sequelae, neurilemmomas in a subcutaneous location may be attached to a major nerve trunk; they require careful surgical dissection to preserve the nerve. We describe a painful, subcutaneous neurilemmoma attached to a cutaneous branch of the lateral popliteal nerve.

Prediction of infusion rates of vecuronium using the bolus test dose technique

Fifty neurosurgical patients were given loading doses of vecuronium 0.1 mg kg-1 followed by boluses of 1, 2 or 4 mg after return of T1 of the train-of-four. Neuromuscular function was assessed simultaneously by palpation of the great toe after peripheral nerve stimulation of the lateral popliteal nerve using a handheld nerve stimulator and also using a Relaxograph attached to one arm. The time taken for the return of T1 after the bolus dose was recorded and an infusion of vecuronium was begun and subsequently adjusted to maintain steady state neuromuscular block. It was possible to predict the infusion rate of vecuronium from the duration of action of a 2-mg or 4-mg but not a 1-mg bolus dose using the handheld stimulator. The infusion rate could also be predicted from the duration of action of the initial loading dose.

Lateral popliteal sciatic nerve block compared with subcutaneous infiltration for analgesia following foot surgery

A new lateral approach to blocking the sciatic nerve in the popliteal fossa is described. In a prospective study, 40 patients scheduled for foot surgery involving osteotomies were allocated randomly into one of two groups following induction of general anaesthesia: group PS (n = 21) received a lateral popliteal sciatic nerve block and group SC (n = 19) received subcutaneous infiltration of the wound. Both groups received 20 ml bupivacaine 0.5% plain. The lateral approach to the popliteal sciatic nerve was found to be an effective, quick, and easy to perform, block. Postoperative analgesia in groups PS lasted a median of 18.0 hr and in group SC lasted 6.3 hr (P < 0.05). The lateral popliteal sciatic nerve block provided effective analgesia following foot surgery and had a high level of patient satisfaction.

Iloprost reduces leukocyte adhesion in skeletal muscle venules following ischaemia in a rat model of femorodistal bypass

Intraarterial bolus treatment with the prostacyclin analogue iloprost appears to have a prolonged beneficial effect on femorodistal bypass graft flow which extends beyond the duration of its vasodilator properties. The effect of iloprost on the microcirculation rendered ischaemic over the time course of a distal bypass operation was investigated in this study without the use of fluorescent light. A rat model was designed to allow prolonged direct observation of leukocyte-venular endothelial adhesion in a femorodistal bypass simulation. The extensor digitorum longus (EDL) muscle of 10 rats was subjected to two 30 minute periods of ischaemia by a non-venous occluding tourniquet and to simulate some of the changes of chronic ischaemia the adverse effect of ischaemia was accentuated by indirect electrical stimulation via the lateral popliteal nerve. Intraarterial bolus treatment with iloprost significantly reduced the total numbers of leukocytes observed in EDL venules, and the numbers exhibiting evidence of adhesion by rolling or sticking to venule endothelium compared with saline controls at one hour post ischaemia. Ischaemia induced vasodilatation and reduced shear stress by a similar and significant amount in both groups. Two periods of ischaemia and reperfusion similar to those which occur during bypass grafting resulted in changes in the distal microcirculation consistent with reperfusion injury. Intraarterial bolus treatment with iloprost prevented these leucocyte-endothelial changes. It appears iloprost may have a role in reducing leukocyte-induced reperfusion injury in femorodistal bypass surgery.

The effect of partial denervation of tibialis anterior (TA) muscle on the number and sizes of motorneurons in TA motornucleus of normal and dystrophic (C57BL dy2j/dy2j) mice

The tibialis anterior (TA) muscle in one leg of normal (C57BL) and dystrophic (dy2j) mice was partially denervated by resection of a part of the lateral popliteal nerve. Two months later the muscle was injected with horseradish peroxidase to permit visualization of the motorneurons that survived. Partial denervation in both C57 and dy2j mice resulted in reduction of the number of motorneurons that supplied the muscle to approximately one-half the normal complement. The surviving motorneurons were found to be significantly larger (about 25%) than their contralateral counterparts. This condition persisted up to 18 months and is not considered to be a transient response to the trauma associated with the partial denervation. When the size of the target tissue was also reduced by extirpation of one-half of TA together with partial denervation, motorneuron size was not found to increase. It is suggested that the increase in size is a response to the metabolic demands placed upon the motorneuron by an increase in the size of the motor unit.

The role of blood flow and/or muscle hypoxia in capillary growth in chronically stimulated fast muscles

Capillary supply, the proportion of oxidative fibres and blood flow were studied in fast rat muscles (tibialis anterior, TA, and extensor digitorum, EDL) made ischaemic by ligation of the common iliac artery, in chronically stimulated muscles and in ischaemic chronically stimulated muscles. Stimulation was carried out for 6 h/day at 10 Hz (three periods of 2 h with 90-120-min intervals between stimulations) for 10-12 days using electrodes implanted in the vicinity of the lateral popliteal nerve. Blood flow (measured by radioactive microspheres) was 3.62 +/- 0.52 ml.100 g-1.min-1 at rest and 78.4 +/- 14.6 ml.100 g-1.min-1 (mean +/- SEM) during isometric contractions at 4 Hz. Ischaemic muscles had significantly lower blood flow at rest as well as during contractions (72 +/- 14% and 25 +/- 4% of the values in contralateral muscles respectively). Stimulated muscles had significantly higher flow than contralateral control muscles during contractions; stimulated ischaemic muscles had normal blood flow at rest, but the increase in flow during contractions was limited to a similar extent to that in ischaemic muscles alone. Of all anatomically present capillaries (staining for alkaline phosphatase in frozen sections) the capillary/fibre ratio increased by 36% in stimulated tibialis anterior, but was not significantly different from control muscles in stimulated ischaemic TA and was even lower than in control muscles in stimulated ischaemic EDL. The proportion of fast oxidative fibres (estimated on the basis of histochemical staining for myosin ATPase and succinate dehydrogenase) increased from 53.2 +/- 3.2% in normal EDL to 82.0 +/- 2.3% in chronically stimulated EDL and to 100% in chronically stimulated ischaemic muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of reinnervation on the distribution of muscle fibre types in the tibialis anterior muscle of the mouse

The distribution of fibre types in the tibialis anterior (TA) muscle of adult mice was examined by means of an immunohistochemical approach, using monoclonal antibodies that recognize different myosin heavy chain isoforms. As has been reported previously, the superficial portion of TA contains almost exclusively type IIB fibres and is almost entirely glycolytic in nature. Following section of the lateral popliteal nerve and rotation of the proximal stump to prevent rematching, it was found that the original pattern was virtually restored within 2 months. One possible explanation for this observation is that the activity pattern of peripheral and deep muscle fibres differs and that this aids in specification of muscle fibre type. Alternatively, the muscle fibres of the superficial portion of TA may be inherently resistant to an alteration of their phenotype with regard to expression of myosin heavy chain.

Peripheral nerve function in patients with chronic bronchitis receiving almitrine or placebo.

A double blind prospective study of the effect of almitrine bismesylate and placebo on peripheral-nerve function was carried out in 12 patients with chronic bronchitis and arterial hypoxaemia (mean (SD) FEV1% predicted 38 (16), arterial oxygen tension (PaO2) 7.56 (0.76) kPa). Of the seven patients who took placebo, none developed symptoms or signs of peripheral neuropathy. One patient who had abnormal lower limb sensory nerve conduction initially showed improvement of sensory conduction but deterioration in motor conduction during the 12 month study period. Two further patients developed some slowing of motor conduction velocities in their right lateral popliteal nerve. Five patients received almitrine and all showed an improvement in PaO2 (mean from 7.0 to 7.9 kPa). None had symptoms or signs of peripheral neuropathy on entry to the study; one patient had evidence of impaired nerve conduction on electrophysiological testing. Three patients developed symptoms and signs of peripheral neuropathy during the 12 months of the study and a fourth developed peripheral neuropathy at 18 months, having continued to receive almitrine. Studies of nerve physiology showed abnormalities in the lower limbs of all four patients. Recovery was poor, possibly because of the long half life of almitrine. The studies suggest that almitrine may precipitate peripheral neuropathy in patients with chronic obstructive pulmonary disease. Patients should be warned of this potential complication so that the drug can be stopped as soon as symptoms develop.

Effects of an anabolic hormone on striated muscle growth and performance.

Chronic administration of an anabolic hormone, nandrolone phenylpropionate, in sedentary female rats for 6 weeks gave a 20% increase in body weight and the same proportional increase in all muscles sampled (heart, diaphragm, soleus, TA, EHP and EDL), such that the muscle/body weight ratio was unchanged. Cardiac muscle was unresponsive to treatment. Acute stimulation of EDL via lateral popliteal nerve gave similar values for contraction time, 1/2 relaxation time and twitch:tetanus ratio in both groups suggesting no slowing of the muscle. Fatigue resistance of EDL was improved with 0.29 +/- 0.029 vs. 0.46 +/- 0.071 of maximum isometric twitch tension being developed after 10 min repetitive stimulation at 4 Hz. This improved endurance was not accompanied by any increase in strength and could not be explained on the basis of cellular hypertrophy, but appears to reflect an increased aerobic capacity of skeletal muscle. The proportion of FOG fibres in EDL increased, 38 +/- 1.1% vs. 46 +/- 1.1%, and this was paralleled in the other skeletal muscles. Specific hypertrophy of FOG and FG fibres could be conclusively demonstrated in soleus and TA, respectively.

Lateral popliteal nerve palsy as a complication of the use of a continuous passive motion knee machine—a case report

Lateral popliteal nerve palsy as a complication of the use of a continuous passive motion knee machine—a case report

Peripheral neuropathy in tropical pancreatic diabetes.

Electrophysiological evaluation of peripheral neuropathy was done in 16 patients with tropical pancreatic diabetes (TPD) and the data compared with those of a matched group of 16 NIDDM patients. Peripheral neuropathy was present in 6 TPD and 5 NIDDM patients. Abnormal motor conduction velocity in the lateral popliteal nerve was seen in 9 TPD patients and in 8 NIDDM patients and biothesiometry was abnormal in 7 patients in each group. One TPD patient had an abnormal F wave in the lower limb. An abnormal sensory potential was recorded in the sural nerve in 6 TPD and 8 NIDDM patients. The study showed that occurrence of peripheral neuropathy in TPD was similar to that in NIDDM. Subclinical neuropathy could be detected by electromyographic recording in both groups of patients.

Reinnervation of fast and slow mammalian muscles by a superfluous number of motor axons

In this study peripheral nerves from flexor digitorum longus, (alien nerve) as well as the deep branch of the muscle's own lateral popliteal nerve were cut and connected to the distal stump ol the lateral popliteal nerve. Extensor digitorum longus and tibialis anterior muscles then became reinnervated to a similar extent by either nerve, showing no preference for its own nerve. A significant proportion of the endplates in these muscles remained permanently supplied by more than one axon, and a proportion of the muscle fibres was supplied by both nerves. No ectopic endplates were formed on fast muscle fibres. The same two nerves were also connected to the slow soleus muscle and this muscle became preferentially reinnervated by the nerve to flexor digitorum longus. In contrast to last muscles, endplates of soleus muscle Obres were only rarely contacted by more than one axon. and ectopic endplates were often found in this muscle. In both types of muscles that had an excess of motor nerves, extensive sprouting persisted for many months. Thus, (a) identical motor nerves induce different patterns of innervation in slow and fast muscles, and (b) muscle fibres do not show a preference for their own nerve.

Changes in capillary distribution in rat fast muscles following nerve crush and reinnervation.

The recovery of muscle weight and contraction tension was measured in rat anterior tibialis muscle following unilateral crushing of the lateral popliteal nerve. Muscle twitch and tetanic tensions and muscle weight had recovered to control values within 6-8 weeks after the nerve was crushed. Capillary supply to each of the four types of muscle fibre present in the intact muscle, and within the groups of adjacent fibres of similar histochemical reaction for succinate dehydrogenase and myofibrillar actomyosin ATPase found in the reinnervated muscle, was computed by the method of Gray & Renkin (1978). Capillary area density (capillaries/mm2) within the grouped regions of the reinnervated muscle was not significantly different from the supply to the same fibre type in intact contralateral muscles. Capillary/fibre ratio for the more glycolytic fibre types (alpha W, alpha?) was lower than in intact muscle, while the values for both alpha R and beta R oxidative fibres agreed closely with control values. It seems that selective growth and loss of capillaries occurs during reinnervation, adjusting capillary supply to meet the changed metabolic demands of the individual fibres following regrouping.

The effect of long-term high-frequency stimulation on capillary density and fibre types in rabbit fast muscles.

Rabbit fast muscles (tibialis anterior, t.a.; extensor digitorum longus, e.d.l.; and peroneal muscles) were stimulated for up to 28 days by electrodes implanted in the vicinity of the lateral popliteal (peroneal) nerve for 8 h/day, using either intermittent high-frequency (three trains at 40 Hz/min, each 5 s duration), or continuous stimulation at 10 Hz. This did not result in muscle hypertrophy even after 28 days. Capillary density (number of capillaries/mm2) was increased in e.d.l. from 251 +/- 3 to 366 +/- 6 after 14 days of stimulation and from 251 +/- 3 to 514 +/- 13 after 28 days of stimulation at 40 Hz. In t.a., capillary density increased from 373 +/- 5 to 583 +/- 10 after 14 days of stimulation at 40 Hz. The capillary/fibre ratio increased in e.d.l. from 1.25 +/- 0.02 to 1.86 +/- 0.04 at 14 days and to 2.07 +/- 0.06 at 28 days. In t.a., capillary/fibre ratio increased from 1.40 +/- 0.03 to 1.83 +/- 0.05 at 14 days. All these changes were significant (P less than 0.0005). Analysis of capillary density, capillary/fibre ratio, fibre areas and proportion of different fibre types in muscles stimulated for shorter periods showed no changes in capillary density, capillary/fibre ratio or fibre areas in e.d.l. or t.a. stimulated for 4 days; there was a decrease in the proportion of fast glycolytic fibres from 42 to 32% (P less than 0.0025) and increase in fast oxidative from 37.6 to 41.2% in e.d.l. Muscles stimulated for 7 days showed increases in capillary density and capillary/fibre ratio in fast predominantly glycolytic fibres in e.d.l., and a decrease in capillary density in fast and slow oxidative fibres in t.a. This was partly due to the increase in fibre areas in these groups (capillary/fibre ratio in t.a. was not significantly changed). No changes were observed in fibre areas in e.d.l. Stimulation at 10 Hz produced increase in capillary/fibre ratio in the vicinity of glycolytic fibres after only 4 days. High-frequency intermittent stimulation leads to a massive capillary growth which starts first in the muscle with a higher proportion of glycolytic fibres (e.d.l.), has a later onset than continuous low-frequency stimulation, and may be due to a combination of high blood flow and metabolic factors.

Sural nerve conduction in mild polyneuropathy.

The motor conduction velocity of the lateral popliteal and tibial nerves as well as the maximal sensory conduction velocity of the sural nerve were measured in 187 patients with signs and symptoms suggestive of mild or early polyneuropathy. The maximal sural conduction velocity gave a high diagnostic yield compared to the motor conduction velocity of the nerves in the legs. In the neuropathies in which the predominant pathological abnormality is known to be axonal degeneration, the maximal sural conduction velocity was often showed in patients with normal motor conduction velocities. The amplitude of the sensory potential did not prove helpful in individual cases because it was often within the normal range.